The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kernel/module.c

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    1 /*
    2    Copyright (C) 2002 Richard Henderson
    3    Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
    4 
    5     This program is free software; you can redistribute it and/or modify
    6     it under the terms of the GNU General Public License as published by
    7     the Free Software Foundation; either version 2 of the License, or
    8     (at your option) any later version.
    9 
   10     This program is distributed in the hope that it will be useful,
   11     but WITHOUT ANY WARRANTY; without even the implied warranty of
   12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   13     GNU General Public License for more details.
   14 
   15     You should have received a copy of the GNU General Public License
   16     along with this program; if not, write to the Free Software
   17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   18 */
   19 #include <linux/export.h>
   20 #include <linux/moduleloader.h>
   21 #include <linux/ftrace_event.h>
   22 #include <linux/init.h>
   23 #include <linux/kallsyms.h>
   24 #include <linux/file.h>
   25 #include <linux/fs.h>
   26 #include <linux/sysfs.h>
   27 #include <linux/kernel.h>
   28 #include <linux/slab.h>
   29 #include <linux/vmalloc.h>
   30 #include <linux/elf.h>
   31 #include <linux/proc_fs.h>
   32 #include <linux/security.h>
   33 #include <linux/seq_file.h>
   34 #include <linux/syscalls.h>
   35 #include <linux/fcntl.h>
   36 #include <linux/rcupdate.h>
   37 #include <linux/capability.h>
   38 #include <linux/cpu.h>
   39 #include <linux/moduleparam.h>
   40 #include <linux/errno.h>
   41 #include <linux/err.h>
   42 #include <linux/vermagic.h>
   43 #include <linux/notifier.h>
   44 #include <linux/sched.h>
   45 #include <linux/stop_machine.h>
   46 #include <linux/device.h>
   47 #include <linux/string.h>
   48 #include <linux/mutex.h>
   49 #include <linux/rculist.h>
   50 #include <asm/uaccess.h>
   51 #include <asm/cacheflush.h>
   52 #include <asm/mmu_context.h>
   53 #include <linux/license.h>
   54 #include <asm/sections.h>
   55 #include <linux/tracepoint.h>
   56 #include <linux/ftrace.h>
   57 #include <linux/async.h>
   58 #include <linux/percpu.h>
   59 #include <linux/kmemleak.h>
   60 #include <linux/jump_label.h>
   61 #include <linux/pfn.h>
   62 #include <linux/bsearch.h>
   63 #include <linux/fips.h>
   64 #include <uapi/linux/module.h>
   65 #include "module-internal.h"
   66 
   67 #define CREATE_TRACE_POINTS
   68 #include <trace/events/module.h>
   69 
   70 #ifndef ARCH_SHF_SMALL
   71 #define ARCH_SHF_SMALL 0
   72 #endif
   73 
   74 /*
   75  * Modules' sections will be aligned on page boundaries
   76  * to ensure complete separation of code and data, but
   77  * only when CONFIG_DEBUG_SET_MODULE_RONX=y
   78  */
   79 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
   80 # define debug_align(X) ALIGN(X, PAGE_SIZE)
   81 #else
   82 # define debug_align(X) (X)
   83 #endif
   84 
   85 /*
   86  * Given BASE and SIZE this macro calculates the number of pages the
   87  * memory regions occupies
   88  */
   89 #define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ?         \
   90                 (PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) - \
   91                          PFN_DOWN((unsigned long)BASE) + 1)     \
   92                 : (0UL))
   93 
   94 /* If this is set, the section belongs in the init part of the module */
   95 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
   96 
   97 /*
   98  * Mutex protects:
   99  * 1) List of modules (also safely readable with preempt_disable),
  100  * 2) module_use links,
  101  * 3) module_addr_min/module_addr_max.
  102  * (delete uses stop_machine/add uses RCU list operations). */
  103 DEFINE_MUTEX(module_mutex);
  104 EXPORT_SYMBOL_GPL(module_mutex);
  105 static LIST_HEAD(modules);
  106 #ifdef CONFIG_KGDB_KDB
  107 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
  108 #endif /* CONFIG_KGDB_KDB */
  109 
  110 #ifdef CONFIG_MODULE_SIG
  111 #ifdef CONFIG_MODULE_SIG_FORCE
  112 static bool sig_enforce = true;
  113 #else
  114 static bool sig_enforce = false;
  115 
  116 static int param_set_bool_enable_only(const char *val,
  117                                       const struct kernel_param *kp)
  118 {
  119         int err;
  120         bool test;
  121         struct kernel_param dummy_kp = *kp;
  122 
  123         dummy_kp.arg = &test;
  124 
  125         err = param_set_bool(val, &dummy_kp);
  126         if (err)
  127                 return err;
  128 
  129         /* Don't let them unset it once it's set! */
  130         if (!test && sig_enforce)
  131                 return -EROFS;
  132 
  133         if (test)
  134                 sig_enforce = true;
  135         return 0;
  136 }
  137 
  138 static const struct kernel_param_ops param_ops_bool_enable_only = {
  139         .set = param_set_bool_enable_only,
  140         .get = param_get_bool,
  141 };
  142 #define param_check_bool_enable_only param_check_bool
  143 
  144 module_param(sig_enforce, bool_enable_only, 0644);
  145 #endif /* !CONFIG_MODULE_SIG_FORCE */
  146 #endif /* CONFIG_MODULE_SIG */
  147 
  148 /* Block module loading/unloading? */
  149 int modules_disabled = 0;
  150 core_param(nomodule, modules_disabled, bint, 0);
  151 
  152 /* Waiting for a module to finish initializing? */
  153 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
  154 
  155 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
  156 
  157 /* Bounds of module allocation, for speeding __module_address.
  158  * Protected by module_mutex. */
  159 static unsigned long module_addr_min = -1UL, module_addr_max = 0;
  160 
  161 int register_module_notifier(struct notifier_block * nb)
  162 {
  163         return blocking_notifier_chain_register(&module_notify_list, nb);
  164 }
  165 EXPORT_SYMBOL(register_module_notifier);
  166 
  167 int unregister_module_notifier(struct notifier_block * nb)
  168 {
  169         return blocking_notifier_chain_unregister(&module_notify_list, nb);
  170 }
  171 EXPORT_SYMBOL(unregister_module_notifier);
  172 
  173 struct load_info {
  174         Elf_Ehdr *hdr;
  175         unsigned long len;
  176         Elf_Shdr *sechdrs;
  177         char *secstrings, *strtab;
  178         unsigned long symoffs, stroffs;
  179         struct _ddebug *debug;
  180         unsigned int num_debug;
  181         bool sig_ok;
  182         struct {
  183                 unsigned int sym, str, mod, vers, info, pcpu;
  184         } index;
  185 };
  186 
  187 /* We require a truly strong try_module_get(): 0 means failure due to
  188    ongoing or failed initialization etc. */
  189 static inline int strong_try_module_get(struct module *mod)
  190 {
  191         BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
  192         if (mod && mod->state == MODULE_STATE_COMING)
  193                 return -EBUSY;
  194         if (try_module_get(mod))
  195                 return 0;
  196         else
  197                 return -ENOENT;
  198 }
  199 
  200 static inline void add_taint_module(struct module *mod, unsigned flag)
  201 {
  202         add_taint(flag);
  203         mod->taints |= (1U << flag);
  204 }
  205 
  206 /*
  207  * A thread that wants to hold a reference to a module only while it
  208  * is running can call this to safely exit.  nfsd and lockd use this.
  209  */
  210 void __module_put_and_exit(struct module *mod, long code)
  211 {
  212         module_put(mod);
  213         do_exit(code);
  214 }
  215 EXPORT_SYMBOL(__module_put_and_exit);
  216 
  217 /* Find a module section: 0 means not found. */
  218 static unsigned int find_sec(const struct load_info *info, const char *name)
  219 {
  220         unsigned int i;
  221 
  222         for (i = 1; i < info->hdr->e_shnum; i++) {
  223                 Elf_Shdr *shdr = &info->sechdrs[i];
  224                 /* Alloc bit cleared means "ignore it." */
  225                 if ((shdr->sh_flags & SHF_ALLOC)
  226                     && strcmp(info->secstrings + shdr->sh_name, name) == 0)
  227                         return i;
  228         }
  229         return 0;
  230 }
  231 
  232 /* Find a module section, or NULL. */
  233 static void *section_addr(const struct load_info *info, const char *name)
  234 {
  235         /* Section 0 has sh_addr 0. */
  236         return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
  237 }
  238 
  239 /* Find a module section, or NULL.  Fill in number of "objects" in section. */
  240 static void *section_objs(const struct load_info *info,
  241                           const char *name,
  242                           size_t object_size,
  243                           unsigned int *num)
  244 {
  245         unsigned int sec = find_sec(info, name);
  246 
  247         /* Section 0 has sh_addr 0 and sh_size 0. */
  248         *num = info->sechdrs[sec].sh_size / object_size;
  249         return (void *)info->sechdrs[sec].sh_addr;
  250 }
  251 
  252 /* Provided by the linker */
  253 extern const struct kernel_symbol __start___ksymtab[];
  254 extern const struct kernel_symbol __stop___ksymtab[];
  255 extern const struct kernel_symbol __start___ksymtab_gpl[];
  256 extern const struct kernel_symbol __stop___ksymtab_gpl[];
  257 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
  258 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
  259 extern const unsigned long __start___kcrctab[];
  260 extern const unsigned long __start___kcrctab_gpl[];
  261 extern const unsigned long __start___kcrctab_gpl_future[];
  262 #ifdef CONFIG_UNUSED_SYMBOLS
  263 extern const struct kernel_symbol __start___ksymtab_unused[];
  264 extern const struct kernel_symbol __stop___ksymtab_unused[];
  265 extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
  266 extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
  267 extern const unsigned long __start___kcrctab_unused[];
  268 extern const unsigned long __start___kcrctab_unused_gpl[];
  269 #endif
  270 
  271 #ifndef CONFIG_MODVERSIONS
  272 #define symversion(base, idx) NULL
  273 #else
  274 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
  275 #endif
  276 
  277 static bool each_symbol_in_section(const struct symsearch *arr,
  278                                    unsigned int arrsize,
  279                                    struct module *owner,
  280                                    bool (*fn)(const struct symsearch *syms,
  281                                               struct module *owner,
  282                                               void *data),
  283                                    void *data)
  284 {
  285         unsigned int j;
  286 
  287         for (j = 0; j < arrsize; j++) {
  288                 if (fn(&arr[j], owner, data))
  289                         return true;
  290         }
  291 
  292         return false;
  293 }
  294 
  295 /* Returns true as soon as fn returns true, otherwise false. */
  296 bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
  297                                     struct module *owner,
  298                                     void *data),
  299                          void *data)
  300 {
  301         struct module *mod;
  302         static const struct symsearch arr[] = {
  303                 { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
  304                   NOT_GPL_ONLY, false },
  305                 { __start___ksymtab_gpl, __stop___ksymtab_gpl,
  306                   __start___kcrctab_gpl,
  307                   GPL_ONLY, false },
  308                 { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
  309                   __start___kcrctab_gpl_future,
  310                   WILL_BE_GPL_ONLY, false },
  311 #ifdef CONFIG_UNUSED_SYMBOLS
  312                 { __start___ksymtab_unused, __stop___ksymtab_unused,
  313                   __start___kcrctab_unused,
  314                   NOT_GPL_ONLY, true },
  315                 { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
  316                   __start___kcrctab_unused_gpl,
  317                   GPL_ONLY, true },
  318 #endif
  319         };
  320 
  321         if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
  322                 return true;
  323 
  324         list_for_each_entry_rcu(mod, &modules, list) {
  325                 struct symsearch arr[] = {
  326                         { mod->syms, mod->syms + mod->num_syms, mod->crcs,
  327                           NOT_GPL_ONLY, false },
  328                         { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
  329                           mod->gpl_crcs,
  330                           GPL_ONLY, false },
  331                         { mod->gpl_future_syms,
  332                           mod->gpl_future_syms + mod->num_gpl_future_syms,
  333                           mod->gpl_future_crcs,
  334                           WILL_BE_GPL_ONLY, false },
  335 #ifdef CONFIG_UNUSED_SYMBOLS
  336                         { mod->unused_syms,
  337                           mod->unused_syms + mod->num_unused_syms,
  338                           mod->unused_crcs,
  339                           NOT_GPL_ONLY, true },
  340                         { mod->unused_gpl_syms,
  341                           mod->unused_gpl_syms + mod->num_unused_gpl_syms,
  342                           mod->unused_gpl_crcs,
  343                           GPL_ONLY, true },
  344 #endif
  345                 };
  346 
  347                 if (mod->state == MODULE_STATE_UNFORMED)
  348                         continue;
  349 
  350                 if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
  351                         return true;
  352         }
  353         return false;
  354 }
  355 EXPORT_SYMBOL_GPL(each_symbol_section);
  356 
  357 struct find_symbol_arg {
  358         /* Input */
  359         const char *name;
  360         bool gplok;
  361         bool warn;
  362 
  363         /* Output */
  364         struct module *owner;
  365         const unsigned long *crc;
  366         const struct kernel_symbol *sym;
  367 };
  368 
  369 static bool check_symbol(const struct symsearch *syms,
  370                                  struct module *owner,
  371                                  unsigned int symnum, void *data)
  372 {
  373         struct find_symbol_arg *fsa = data;
  374 
  375         if (!fsa->gplok) {
  376                 if (syms->licence == GPL_ONLY)
  377                         return false;
  378                 if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
  379                         printk(KERN_WARNING "Symbol %s is being used "
  380                                "by a non-GPL module, which will not "
  381                                "be allowed in the future\n", fsa->name);
  382                 }
  383         }
  384 
  385 #ifdef CONFIG_UNUSED_SYMBOLS
  386         if (syms->unused && fsa->warn) {
  387                 printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
  388                        "however this module is using it.\n", fsa->name);
  389                 printk(KERN_WARNING
  390                        "This symbol will go away in the future.\n");
  391                 printk(KERN_WARNING
  392                        "Please evalute if this is the right api to use and if "
  393                        "it really is, submit a report the linux kernel "
  394                        "mailinglist together with submitting your code for "
  395                        "inclusion.\n");
  396         }
  397 #endif
  398 
  399         fsa->owner = owner;
  400         fsa->crc = symversion(syms->crcs, symnum);
  401         fsa->sym = &syms->start[symnum];
  402         return true;
  403 }
  404 
  405 static int cmp_name(const void *va, const void *vb)
  406 {
  407         const char *a;
  408         const struct kernel_symbol *b;
  409         a = va; b = vb;
  410         return strcmp(a, b->name);
  411 }
  412 
  413 static bool find_symbol_in_section(const struct symsearch *syms,
  414                                    struct module *owner,
  415                                    void *data)
  416 {
  417         struct find_symbol_arg *fsa = data;
  418         struct kernel_symbol *sym;
  419 
  420         sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
  421                         sizeof(struct kernel_symbol), cmp_name);
  422 
  423         if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
  424                 return true;
  425 
  426         return false;
  427 }
  428 
  429 /* Find a symbol and return it, along with, (optional) crc and
  430  * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
  431 const struct kernel_symbol *find_symbol(const char *name,
  432                                         struct module **owner,
  433                                         const unsigned long **crc,
  434                                         bool gplok,
  435                                         bool warn)
  436 {
  437         struct find_symbol_arg fsa;
  438 
  439         fsa.name = name;
  440         fsa.gplok = gplok;
  441         fsa.warn = warn;
  442 
  443         if (each_symbol_section(find_symbol_in_section, &fsa)) {
  444                 if (owner)
  445                         *owner = fsa.owner;
  446                 if (crc)
  447                         *crc = fsa.crc;
  448                 return fsa.sym;
  449         }
  450 
  451         pr_debug("Failed to find symbol %s\n", name);
  452         return NULL;
  453 }
  454 EXPORT_SYMBOL_GPL(find_symbol);
  455 
  456 /* Search for module by name: must hold module_mutex. */
  457 static struct module *find_module_all(const char *name,
  458                                       bool even_unformed)
  459 {
  460         struct module *mod;
  461 
  462         list_for_each_entry(mod, &modules, list) {
  463                 if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
  464                         continue;
  465                 if (strcmp(mod->name, name) == 0)
  466                         return mod;
  467         }
  468         return NULL;
  469 }
  470 
  471 struct module *find_module(const char *name)
  472 {
  473         return find_module_all(name, false);
  474 }
  475 EXPORT_SYMBOL_GPL(find_module);
  476 
  477 #ifdef CONFIG_SMP
  478 
  479 static inline void __percpu *mod_percpu(struct module *mod)
  480 {
  481         return mod->percpu;
  482 }
  483 
  484 static int percpu_modalloc(struct module *mod,
  485                            unsigned long size, unsigned long align)
  486 {
  487         if (align > PAGE_SIZE) {
  488                 printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
  489                        mod->name, align, PAGE_SIZE);
  490                 align = PAGE_SIZE;
  491         }
  492 
  493         mod->percpu = __alloc_reserved_percpu(size, align);
  494         if (!mod->percpu) {
  495                 printk(KERN_WARNING
  496                        "%s: Could not allocate %lu bytes percpu data\n",
  497                        mod->name, size);
  498                 return -ENOMEM;
  499         }
  500         mod->percpu_size = size;
  501         return 0;
  502 }
  503 
  504 static void percpu_modfree(struct module *mod)
  505 {
  506         free_percpu(mod->percpu);
  507 }
  508 
  509 static unsigned int find_pcpusec(struct load_info *info)
  510 {
  511         return find_sec(info, ".data..percpu");
  512 }
  513 
  514 static void percpu_modcopy(struct module *mod,
  515                            const void *from, unsigned long size)
  516 {
  517         int cpu;
  518 
  519         for_each_possible_cpu(cpu)
  520                 memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
  521 }
  522 
  523 /**
  524  * is_module_percpu_address - test whether address is from module static percpu
  525  * @addr: address to test
  526  *
  527  * Test whether @addr belongs to module static percpu area.
  528  *
  529  * RETURNS:
  530  * %true if @addr is from module static percpu area
  531  */
  532 bool is_module_percpu_address(unsigned long addr)
  533 {
  534         struct module *mod;
  535         unsigned int cpu;
  536 
  537         preempt_disable();
  538 
  539         list_for_each_entry_rcu(mod, &modules, list) {
  540                 if (mod->state == MODULE_STATE_UNFORMED)
  541                         continue;
  542                 if (!mod->percpu_size)
  543                         continue;
  544                 for_each_possible_cpu(cpu) {
  545                         void *start = per_cpu_ptr(mod->percpu, cpu);
  546 
  547                         if ((void *)addr >= start &&
  548                             (void *)addr < start + mod->percpu_size) {
  549                                 preempt_enable();
  550                                 return true;
  551                         }
  552                 }
  553         }
  554 
  555         preempt_enable();
  556         return false;
  557 }
  558 
  559 #else /* ... !CONFIG_SMP */
  560 
  561 static inline void __percpu *mod_percpu(struct module *mod)
  562 {
  563         return NULL;
  564 }
  565 static inline int percpu_modalloc(struct module *mod,
  566                                   unsigned long size, unsigned long align)
  567 {
  568         return -ENOMEM;
  569 }
  570 static inline void percpu_modfree(struct module *mod)
  571 {
  572 }
  573 static unsigned int find_pcpusec(struct load_info *info)
  574 {
  575         return 0;
  576 }
  577 static inline void percpu_modcopy(struct module *mod,
  578                                   const void *from, unsigned long size)
  579 {
  580         /* pcpusec should be 0, and size of that section should be 0. */
  581         BUG_ON(size != 0);
  582 }
  583 bool is_module_percpu_address(unsigned long addr)
  584 {
  585         return false;
  586 }
  587 
  588 #endif /* CONFIG_SMP */
  589 
  590 #define MODINFO_ATTR(field)     \
  591 static void setup_modinfo_##field(struct module *mod, const char *s)  \
  592 {                                                                     \
  593         mod->field = kstrdup(s, GFP_KERNEL);                          \
  594 }                                                                     \
  595 static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
  596                         struct module_kobject *mk, char *buffer)      \
  597 {                                                                     \
  598         return sprintf(buffer, "%s\n", mk->mod->field);               \
  599 }                                                                     \
  600 static int modinfo_##field##_exists(struct module *mod)               \
  601 {                                                                     \
  602         return mod->field != NULL;                                    \
  603 }                                                                     \
  604 static void free_modinfo_##field(struct module *mod)                  \
  605 {                                                                     \
  606         kfree(mod->field);                                            \
  607         mod->field = NULL;                                            \
  608 }                                                                     \
  609 static struct module_attribute modinfo_##field = {                    \
  610         .attr = { .name = __stringify(field), .mode = 0444 },         \
  611         .show = show_modinfo_##field,                                 \
  612         .setup = setup_modinfo_##field,                               \
  613         .test = modinfo_##field##_exists,                             \
  614         .free = free_modinfo_##field,                                 \
  615 };
  616 
  617 MODINFO_ATTR(version);
  618 MODINFO_ATTR(srcversion);
  619 
  620 static char last_unloaded_module[MODULE_NAME_LEN+1];
  621 
  622 #ifdef CONFIG_MODULE_UNLOAD
  623 
  624 EXPORT_TRACEPOINT_SYMBOL(module_get);
  625 
  626 /* Init the unload section of the module. */
  627 static int module_unload_init(struct module *mod)
  628 {
  629         mod->refptr = alloc_percpu(struct module_ref);
  630         if (!mod->refptr)
  631                 return -ENOMEM;
  632 
  633         INIT_LIST_HEAD(&mod->source_list);
  634         INIT_LIST_HEAD(&mod->target_list);
  635 
  636         /* Hold reference count during initialization. */
  637         __this_cpu_write(mod->refptr->incs, 1);
  638         /* Backwards compatibility macros put refcount during init. */
  639         mod->waiter = current;
  640 
  641         return 0;
  642 }
  643 
  644 /* Does a already use b? */
  645 static int already_uses(struct module *a, struct module *b)
  646 {
  647         struct module_use *use;
  648 
  649         list_for_each_entry(use, &b->source_list, source_list) {
  650                 if (use->source == a) {
  651                         pr_debug("%s uses %s!\n", a->name, b->name);
  652                         return 1;
  653                 }
  654         }
  655         pr_debug("%s does not use %s!\n", a->name, b->name);
  656         return 0;
  657 }
  658 
  659 /*
  660  * Module a uses b
  661  *  - we add 'a' as a "source", 'b' as a "target" of module use
  662  *  - the module_use is added to the list of 'b' sources (so
  663  *    'b' can walk the list to see who sourced them), and of 'a'
  664  *    targets (so 'a' can see what modules it targets).
  665  */
  666 static int add_module_usage(struct module *a, struct module *b)
  667 {
  668         struct module_use *use;
  669 
  670         pr_debug("Allocating new usage for %s.\n", a->name);
  671         use = kmalloc(sizeof(*use), GFP_ATOMIC);
  672         if (!use) {
  673                 printk(KERN_WARNING "%s: out of memory loading\n", a->name);
  674                 return -ENOMEM;
  675         }
  676 
  677         use->source = a;
  678         use->target = b;
  679         list_add(&use->source_list, &b->source_list);
  680         list_add(&use->target_list, &a->target_list);
  681         return 0;
  682 }
  683 
  684 /* Module a uses b: caller needs module_mutex() */
  685 int ref_module(struct module *a, struct module *b)
  686 {
  687         int err;
  688 
  689         if (b == NULL || already_uses(a, b))
  690                 return 0;
  691 
  692         /* If module isn't available, we fail. */
  693         err = strong_try_module_get(b);
  694         if (err)
  695                 return err;
  696 
  697         err = add_module_usage(a, b);
  698         if (err) {
  699                 module_put(b);
  700                 return err;
  701         }
  702         return 0;
  703 }
  704 EXPORT_SYMBOL_GPL(ref_module);
  705 
  706 /* Clear the unload stuff of the module. */
  707 static void module_unload_free(struct module *mod)
  708 {
  709         struct module_use *use, *tmp;
  710 
  711         mutex_lock(&module_mutex);
  712         list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
  713                 struct module *i = use->target;
  714                 pr_debug("%s unusing %s\n", mod->name, i->name);
  715                 module_put(i);
  716                 list_del(&use->source_list);
  717                 list_del(&use->target_list);
  718                 kfree(use);
  719         }
  720         mutex_unlock(&module_mutex);
  721 
  722         free_percpu(mod->refptr);
  723 }
  724 
  725 #ifdef CONFIG_MODULE_FORCE_UNLOAD
  726 static inline int try_force_unload(unsigned int flags)
  727 {
  728         int ret = (flags & O_TRUNC);
  729         if (ret)
  730                 add_taint(TAINT_FORCED_RMMOD);
  731         return ret;
  732 }
  733 #else
  734 static inline int try_force_unload(unsigned int flags)
  735 {
  736         return 0;
  737 }
  738 #endif /* CONFIG_MODULE_FORCE_UNLOAD */
  739 
  740 struct stopref
  741 {
  742         struct module *mod;
  743         int flags;
  744         int *forced;
  745 };
  746 
  747 /* Whole machine is stopped with interrupts off when this runs. */
  748 static int __try_stop_module(void *_sref)
  749 {
  750         struct stopref *sref = _sref;
  751 
  752         /* If it's not unused, quit unless we're forcing. */
  753         if (module_refcount(sref->mod) != 0) {
  754                 if (!(*sref->forced = try_force_unload(sref->flags)))
  755                         return -EWOULDBLOCK;
  756         }
  757 
  758         /* Mark it as dying. */
  759         sref->mod->state = MODULE_STATE_GOING;
  760         return 0;
  761 }
  762 
  763 static int try_stop_module(struct module *mod, int flags, int *forced)
  764 {
  765         if (flags & O_NONBLOCK) {
  766                 struct stopref sref = { mod, flags, forced };
  767 
  768                 return stop_machine(__try_stop_module, &sref, NULL);
  769         } else {
  770                 /* We don't need to stop the machine for this. */
  771                 mod->state = MODULE_STATE_GOING;
  772                 synchronize_sched();
  773                 return 0;
  774         }
  775 }
  776 
  777 unsigned long module_refcount(struct module *mod)
  778 {
  779         unsigned long incs = 0, decs = 0;
  780         int cpu;
  781 
  782         for_each_possible_cpu(cpu)
  783                 decs += per_cpu_ptr(mod->refptr, cpu)->decs;
  784         /*
  785          * ensure the incs are added up after the decs.
  786          * module_put ensures incs are visible before decs with smp_wmb.
  787          *
  788          * This 2-count scheme avoids the situation where the refcount
  789          * for CPU0 is read, then CPU0 increments the module refcount,
  790          * then CPU1 drops that refcount, then the refcount for CPU1 is
  791          * read. We would record a decrement but not its corresponding
  792          * increment so we would see a low count (disaster).
  793          *
  794          * Rare situation? But module_refcount can be preempted, and we
  795          * might be tallying up 4096+ CPUs. So it is not impossible.
  796          */
  797         smp_rmb();
  798         for_each_possible_cpu(cpu)
  799                 incs += per_cpu_ptr(mod->refptr, cpu)->incs;
  800         return incs - decs;
  801 }
  802 EXPORT_SYMBOL(module_refcount);
  803 
  804 /* This exists whether we can unload or not */
  805 static void free_module(struct module *mod);
  806 
  807 static void wait_for_zero_refcount(struct module *mod)
  808 {
  809         /* Since we might sleep for some time, release the mutex first */
  810         mutex_unlock(&module_mutex);
  811         for (;;) {
  812                 pr_debug("Looking at refcount...\n");
  813                 set_current_state(TASK_UNINTERRUPTIBLE);
  814                 if (module_refcount(mod) == 0)
  815                         break;
  816                 schedule();
  817         }
  818         current->state = TASK_RUNNING;
  819         mutex_lock(&module_mutex);
  820 }
  821 
  822 SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
  823                 unsigned int, flags)
  824 {
  825         struct module *mod;
  826         char name[MODULE_NAME_LEN];
  827         int ret, forced = 0;
  828 
  829         if (!capable(CAP_SYS_MODULE) || modules_disabled)
  830                 return -EPERM;
  831 
  832         if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
  833                 return -EFAULT;
  834         name[MODULE_NAME_LEN-1] = '\0';
  835 
  836         if (mutex_lock_interruptible(&module_mutex) != 0)
  837                 return -EINTR;
  838 
  839         mod = find_module(name);
  840         if (!mod) {
  841                 ret = -ENOENT;
  842                 goto out;
  843         }
  844 
  845         if (!list_empty(&mod->source_list)) {
  846                 /* Other modules depend on us: get rid of them first. */
  847                 ret = -EWOULDBLOCK;
  848                 goto out;
  849         }
  850 
  851         /* Doing init or already dying? */
  852         if (mod->state != MODULE_STATE_LIVE) {
  853                 /* FIXME: if (force), slam module count and wake up
  854                    waiter --RR */
  855                 pr_debug("%s already dying\n", mod->name);
  856                 ret = -EBUSY;
  857                 goto out;
  858         }
  859 
  860         /* If it has an init func, it must have an exit func to unload */
  861         if (mod->init && !mod->exit) {
  862                 forced = try_force_unload(flags);
  863                 if (!forced) {
  864                         /* This module can't be removed */
  865                         ret = -EBUSY;
  866                         goto out;
  867                 }
  868         }
  869 
  870         /* Set this up before setting mod->state */
  871         mod->waiter = current;
  872 
  873         /* Stop the machine so refcounts can't move and disable module. */
  874         ret = try_stop_module(mod, flags, &forced);
  875         if (ret != 0)
  876                 goto out;
  877 
  878         /* Never wait if forced. */
  879         if (!forced && module_refcount(mod) != 0)
  880                 wait_for_zero_refcount(mod);
  881 
  882         mutex_unlock(&module_mutex);
  883         /* Final destruction now no one is using it. */
  884         if (mod->exit != NULL)
  885                 mod->exit();
  886         blocking_notifier_call_chain(&module_notify_list,
  887                                      MODULE_STATE_GOING, mod);
  888         async_synchronize_full();
  889 
  890         /* Store the name of the last unloaded module for diagnostic purposes */
  891         strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
  892 
  893         free_module(mod);
  894         return 0;
  895 out:
  896         mutex_unlock(&module_mutex);
  897         return ret;
  898 }
  899 
  900 static inline void print_unload_info(struct seq_file *m, struct module *mod)
  901 {
  902         struct module_use *use;
  903         int printed_something = 0;
  904 
  905         seq_printf(m, " %lu ", module_refcount(mod));
  906 
  907         /* Always include a trailing , so userspace can differentiate
  908            between this and the old multi-field proc format. */
  909         list_for_each_entry(use, &mod->source_list, source_list) {
  910                 printed_something = 1;
  911                 seq_printf(m, "%s,", use->source->name);
  912         }
  913 
  914         if (mod->init != NULL && mod->exit == NULL) {
  915                 printed_something = 1;
  916                 seq_printf(m, "[permanent],");
  917         }
  918 
  919         if (!printed_something)
  920                 seq_printf(m, "-");
  921 }
  922 
  923 void __symbol_put(const char *symbol)
  924 {
  925         struct module *owner;
  926 
  927         preempt_disable();
  928         if (!find_symbol(symbol, &owner, NULL, true, false))
  929                 BUG();
  930         module_put(owner);
  931         preempt_enable();
  932 }
  933 EXPORT_SYMBOL(__symbol_put);
  934 
  935 /* Note this assumes addr is a function, which it currently always is. */
  936 void symbol_put_addr(void *addr)
  937 {
  938         struct module *modaddr;
  939         unsigned long a = (unsigned long)dereference_function_descriptor(addr);
  940 
  941         if (core_kernel_text(a))
  942                 return;
  943 
  944         /* module_text_address is safe here: we're supposed to have reference
  945          * to module from symbol_get, so it can't go away. */
  946         modaddr = __module_text_address(a);
  947         BUG_ON(!modaddr);
  948         module_put(modaddr);
  949 }
  950 EXPORT_SYMBOL_GPL(symbol_put_addr);
  951 
  952 static ssize_t show_refcnt(struct module_attribute *mattr,
  953                            struct module_kobject *mk, char *buffer)
  954 {
  955         return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
  956 }
  957 
  958 static struct module_attribute modinfo_refcnt =
  959         __ATTR(refcnt, 0444, show_refcnt, NULL);
  960 
  961 void __module_get(struct module *module)
  962 {
  963         if (module) {
  964                 preempt_disable();
  965                 __this_cpu_inc(module->refptr->incs);
  966                 trace_module_get(module, _RET_IP_);
  967                 preempt_enable();
  968         }
  969 }
  970 EXPORT_SYMBOL(__module_get);
  971 
  972 bool try_module_get(struct module *module)
  973 {
  974         bool ret = true;
  975 
  976         if (module) {
  977                 preempt_disable();
  978 
  979                 if (likely(module_is_live(module))) {
  980                         __this_cpu_inc(module->refptr->incs);
  981                         trace_module_get(module, _RET_IP_);
  982                 } else
  983                         ret = false;
  984 
  985                 preempt_enable();
  986         }
  987         return ret;
  988 }
  989 EXPORT_SYMBOL(try_module_get);
  990 
  991 void module_put(struct module *module)
  992 {
  993         if (module) {
  994                 preempt_disable();
  995                 smp_wmb(); /* see comment in module_refcount */
  996                 __this_cpu_inc(module->refptr->decs);
  997 
  998                 trace_module_put(module, _RET_IP_);
  999                 /* Maybe they're waiting for us to drop reference? */
 1000                 if (unlikely(!module_is_live(module)))
 1001                         wake_up_process(module->waiter);
 1002                 preempt_enable();
 1003         }
 1004 }
 1005 EXPORT_SYMBOL(module_put);
 1006 
 1007 #else /* !CONFIG_MODULE_UNLOAD */
 1008 static inline void print_unload_info(struct seq_file *m, struct module *mod)
 1009 {
 1010         /* We don't know the usage count, or what modules are using. */
 1011         seq_printf(m, " - -");
 1012 }
 1013 
 1014 static inline void module_unload_free(struct module *mod)
 1015 {
 1016 }
 1017 
 1018 int ref_module(struct module *a, struct module *b)
 1019 {
 1020         return strong_try_module_get(b);
 1021 }
 1022 EXPORT_SYMBOL_GPL(ref_module);
 1023 
 1024 static inline int module_unload_init(struct module *mod)
 1025 {
 1026         return 0;
 1027 }
 1028 #endif /* CONFIG_MODULE_UNLOAD */
 1029 
 1030 static size_t module_flags_taint(struct module *mod, char *buf)
 1031 {
 1032         size_t l = 0;
 1033 
 1034         if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
 1035                 buf[l++] = 'P';
 1036         if (mod->taints & (1 << TAINT_OOT_MODULE))
 1037                 buf[l++] = 'O';
 1038         if (mod->taints & (1 << TAINT_FORCED_MODULE))
 1039                 buf[l++] = 'F';
 1040         if (mod->taints & (1 << TAINT_CRAP))
 1041                 buf[l++] = 'C';
 1042         /*
 1043          * TAINT_FORCED_RMMOD: could be added.
 1044          * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
 1045          * apply to modules.
 1046          */
 1047         return l;
 1048 }
 1049 
 1050 static ssize_t show_initstate(struct module_attribute *mattr,
 1051                               struct module_kobject *mk, char *buffer)
 1052 {
 1053         const char *state = "unknown";
 1054 
 1055         switch (mk->mod->state) {
 1056         case MODULE_STATE_LIVE:
 1057                 state = "live";
 1058                 break;
 1059         case MODULE_STATE_COMING:
 1060                 state = "coming";
 1061                 break;
 1062         case MODULE_STATE_GOING:
 1063                 state = "going";
 1064                 break;
 1065         default:
 1066                 BUG();
 1067         }
 1068         return sprintf(buffer, "%s\n", state);
 1069 }
 1070 
 1071 static struct module_attribute modinfo_initstate =
 1072         __ATTR(initstate, 0444, show_initstate, NULL);
 1073 
 1074 static ssize_t store_uevent(struct module_attribute *mattr,
 1075                             struct module_kobject *mk,
 1076                             const char *buffer, size_t count)
 1077 {
 1078         enum kobject_action action;
 1079 
 1080         if (kobject_action_type(buffer, count, &action) == 0)
 1081                 kobject_uevent(&mk->kobj, action);
 1082         return count;
 1083 }
 1084 
 1085 struct module_attribute module_uevent =
 1086         __ATTR(uevent, 0200, NULL, store_uevent);
 1087 
 1088 static ssize_t show_coresize(struct module_attribute *mattr,
 1089                              struct module_kobject *mk, char *buffer)
 1090 {
 1091         return sprintf(buffer, "%u\n", mk->mod->core_size);
 1092 }
 1093 
 1094 static struct module_attribute modinfo_coresize =
 1095         __ATTR(coresize, 0444, show_coresize, NULL);
 1096 
 1097 static ssize_t show_initsize(struct module_attribute *mattr,
 1098                              struct module_kobject *mk, char *buffer)
 1099 {
 1100         return sprintf(buffer, "%u\n", mk->mod->init_size);
 1101 }
 1102 
 1103 static struct module_attribute modinfo_initsize =
 1104         __ATTR(initsize, 0444, show_initsize, NULL);
 1105 
 1106 static ssize_t show_taint(struct module_attribute *mattr,
 1107                           struct module_kobject *mk, char *buffer)
 1108 {
 1109         size_t l;
 1110 
 1111         l = module_flags_taint(mk->mod, buffer);
 1112         buffer[l++] = '\n';
 1113         return l;
 1114 }
 1115 
 1116 static struct module_attribute modinfo_taint =
 1117         __ATTR(taint, 0444, show_taint, NULL);
 1118 
 1119 static struct module_attribute *modinfo_attrs[] = {
 1120         &module_uevent,
 1121         &modinfo_version,
 1122         &modinfo_srcversion,
 1123         &modinfo_initstate,
 1124         &modinfo_coresize,
 1125         &modinfo_initsize,
 1126         &modinfo_taint,
 1127 #ifdef CONFIG_MODULE_UNLOAD
 1128         &modinfo_refcnt,
 1129 #endif
 1130         NULL,
 1131 };
 1132 
 1133 static const char vermagic[] = VERMAGIC_STRING;
 1134 
 1135 static int try_to_force_load(struct module *mod, const char *reason)
 1136 {
 1137 #ifdef CONFIG_MODULE_FORCE_LOAD
 1138         if (!test_taint(TAINT_FORCED_MODULE))
 1139                 printk(KERN_WARNING "%s: %s: kernel tainted.\n",
 1140                        mod->name, reason);
 1141         add_taint_module(mod, TAINT_FORCED_MODULE);
 1142         return 0;
 1143 #else
 1144         return -ENOEXEC;
 1145 #endif
 1146 }
 1147 
 1148 #ifdef CONFIG_MODVERSIONS
 1149 /* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
 1150 static unsigned long maybe_relocated(unsigned long crc,
 1151                                      const struct module *crc_owner)
 1152 {
 1153 #ifdef ARCH_RELOCATES_KCRCTAB
 1154         if (crc_owner == NULL)
 1155                 return crc - (unsigned long)reloc_start;
 1156 #endif
 1157         return crc;
 1158 }
 1159 
 1160 static int check_version(Elf_Shdr *sechdrs,
 1161                          unsigned int versindex,
 1162                          const char *symname,
 1163                          struct module *mod, 
 1164                          const unsigned long *crc,
 1165                          const struct module *crc_owner)
 1166 {
 1167         unsigned int i, num_versions;
 1168         struct modversion_info *versions;
 1169 
 1170         /* Exporting module didn't supply crcs?  OK, we're already tainted. */
 1171         if (!crc)
 1172                 return 1;
 1173 
 1174         /* No versions at all?  modprobe --force does this. */
 1175         if (versindex == 0)
 1176                 return try_to_force_load(mod, symname) == 0;
 1177 
 1178         versions = (void *) sechdrs[versindex].sh_addr;
 1179         num_versions = sechdrs[versindex].sh_size
 1180                 / sizeof(struct modversion_info);
 1181 
 1182         for (i = 0; i < num_versions; i++) {
 1183                 if (strcmp(versions[i].name, symname) != 0)
 1184                         continue;
 1185 
 1186                 if (versions[i].crc == maybe_relocated(*crc, crc_owner))
 1187                         return 1;
 1188                 pr_debug("Found checksum %lX vs module %lX\n",
 1189                        maybe_relocated(*crc, crc_owner), versions[i].crc);
 1190                 goto bad_version;
 1191         }
 1192 
 1193         printk(KERN_WARNING "%s: no symbol version for %s\n",
 1194                mod->name, symname);
 1195         return 0;
 1196 
 1197 bad_version:
 1198         printk("%s: disagrees about version of symbol %s\n",
 1199                mod->name, symname);
 1200         return 0;
 1201 }
 1202 
 1203 static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 1204                                           unsigned int versindex,
 1205                                           struct module *mod)
 1206 {
 1207         const unsigned long *crc;
 1208 
 1209         /* Since this should be found in kernel (which can't be removed),
 1210          * no locking is necessary. */
 1211         if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
 1212                          &crc, true, false))
 1213                 BUG();
 1214         return check_version(sechdrs, versindex, "module_layout", mod, crc,
 1215                              NULL);
 1216 }
 1217 
 1218 /* First part is kernel version, which we ignore if module has crcs. */
 1219 static inline int same_magic(const char *amagic, const char *bmagic,
 1220                              bool has_crcs)
 1221 {
 1222         if (has_crcs) {
 1223                 amagic += strcspn(amagic, " ");
 1224                 bmagic += strcspn(bmagic, " ");
 1225         }
 1226         return strcmp(amagic, bmagic) == 0;
 1227 }
 1228 #else
 1229 static inline int check_version(Elf_Shdr *sechdrs,
 1230                                 unsigned int versindex,
 1231                                 const char *symname,
 1232                                 struct module *mod, 
 1233                                 const unsigned long *crc,
 1234                                 const struct module *crc_owner)
 1235 {
 1236         return 1;
 1237 }
 1238 
 1239 static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 1240                                           unsigned int versindex,
 1241                                           struct module *mod)
 1242 {
 1243         return 1;
 1244 }
 1245 
 1246 static inline int same_magic(const char *amagic, const char *bmagic,
 1247                              bool has_crcs)
 1248 {
 1249         return strcmp(amagic, bmagic) == 0;
 1250 }
 1251 #endif /* CONFIG_MODVERSIONS */
 1252 
 1253 /* Resolve a symbol for this module.  I.e. if we find one, record usage. */
 1254 static const struct kernel_symbol *resolve_symbol(struct module *mod,
 1255                                                   const struct load_info *info,
 1256                                                   const char *name,
 1257                                                   char ownername[])
 1258 {
 1259         struct module *owner;
 1260         const struct kernel_symbol *sym;
 1261         const unsigned long *crc;
 1262         int err;
 1263 
 1264         mutex_lock(&module_mutex);
 1265         sym = find_symbol(name, &owner, &crc,
 1266                           !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
 1267         if (!sym)
 1268                 goto unlock;
 1269 
 1270         if (!check_version(info->sechdrs, info->index.vers, name, mod, crc,
 1271                            owner)) {
 1272                 sym = ERR_PTR(-EINVAL);
 1273                 goto getname;
 1274         }
 1275 
 1276         err = ref_module(mod, owner);
 1277         if (err) {
 1278                 sym = ERR_PTR(err);
 1279                 goto getname;
 1280         }
 1281 
 1282 getname:
 1283         /* We must make copy under the lock if we failed to get ref. */
 1284         strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
 1285 unlock:
 1286         mutex_unlock(&module_mutex);
 1287         return sym;
 1288 }
 1289 
 1290 static const struct kernel_symbol *
 1291 resolve_symbol_wait(struct module *mod,
 1292                     const struct load_info *info,
 1293                     const char *name)
 1294 {
 1295         const struct kernel_symbol *ksym;
 1296         char owner[MODULE_NAME_LEN];
 1297 
 1298         if (wait_event_interruptible_timeout(module_wq,
 1299                         !IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
 1300                         || PTR_ERR(ksym) != -EBUSY,
 1301                                              30 * HZ) <= 0) {
 1302                 printk(KERN_WARNING "%s: gave up waiting for init of module %s.\n",
 1303                        mod->name, owner);
 1304         }
 1305         return ksym;
 1306 }
 1307 
 1308 /*
 1309  * /sys/module/foo/sections stuff
 1310  * J. Corbet <corbet@lwn.net>
 1311  */
 1312 #ifdef CONFIG_SYSFS
 1313 
 1314 #ifdef CONFIG_KALLSYMS
 1315 static inline bool sect_empty(const Elf_Shdr *sect)
 1316 {
 1317         return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
 1318 }
 1319 
 1320 struct module_sect_attr
 1321 {
 1322         struct module_attribute mattr;
 1323         char *name;
 1324         unsigned long address;
 1325 };
 1326 
 1327 struct module_sect_attrs
 1328 {
 1329         struct attribute_group grp;
 1330         unsigned int nsections;
 1331         struct module_sect_attr attrs[0];
 1332 };
 1333 
 1334 static ssize_t module_sect_show(struct module_attribute *mattr,
 1335                                 struct module_kobject *mk, char *buf)
 1336 {
 1337         struct module_sect_attr *sattr =
 1338                 container_of(mattr, struct module_sect_attr, mattr);
 1339         return sprintf(buf, "0x%pK\n", (void *)sattr->address);
 1340 }
 1341 
 1342 static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
 1343 {
 1344         unsigned int section;
 1345 
 1346         for (section = 0; section < sect_attrs->nsections; section++)
 1347                 kfree(sect_attrs->attrs[section].name);
 1348         kfree(sect_attrs);
 1349 }
 1350 
 1351 static void add_sect_attrs(struct module *mod, const struct load_info *info)
 1352 {
 1353         unsigned int nloaded = 0, i, size[2];
 1354         struct module_sect_attrs *sect_attrs;
 1355         struct module_sect_attr *sattr;
 1356         struct attribute **gattr;
 1357 
 1358         /* Count loaded sections and allocate structures */
 1359         for (i = 0; i < info->hdr->e_shnum; i++)
 1360                 if (!sect_empty(&info->sechdrs[i]))
 1361                         nloaded++;
 1362         size[0] = ALIGN(sizeof(*sect_attrs)
 1363                         + nloaded * sizeof(sect_attrs->attrs[0]),
 1364                         sizeof(sect_attrs->grp.attrs[0]));
 1365         size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]);
 1366         sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
 1367         if (sect_attrs == NULL)
 1368                 return;
 1369 
 1370         /* Setup section attributes. */
 1371         sect_attrs->grp.name = "sections";
 1372         sect_attrs->grp.attrs = (void *)sect_attrs + size[0];
 1373 
 1374         sect_attrs->nsections = 0;
 1375         sattr = &sect_attrs->attrs[0];
 1376         gattr = &sect_attrs->grp.attrs[0];
 1377         for (i = 0; i < info->hdr->e_shnum; i++) {
 1378                 Elf_Shdr *sec = &info->sechdrs[i];
 1379                 if (sect_empty(sec))
 1380                         continue;
 1381                 sattr->address = sec->sh_addr;
 1382                 sattr->name = kstrdup(info->secstrings + sec->sh_name,
 1383                                         GFP_KERNEL);
 1384                 if (sattr->name == NULL)
 1385                         goto out;
 1386                 sect_attrs->nsections++;
 1387                 sysfs_attr_init(&sattr->mattr.attr);
 1388                 sattr->mattr.show = module_sect_show;
 1389                 sattr->mattr.store = NULL;
 1390                 sattr->mattr.attr.name = sattr->name;
 1391                 sattr->mattr.attr.mode = S_IRUGO;
 1392                 *(gattr++) = &(sattr++)->mattr.attr;
 1393         }
 1394         *gattr = NULL;
 1395 
 1396         if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
 1397                 goto out;
 1398 
 1399         mod->sect_attrs = sect_attrs;
 1400         return;
 1401   out:
 1402         free_sect_attrs(sect_attrs);
 1403 }
 1404 
 1405 static void remove_sect_attrs(struct module *mod)
 1406 {
 1407         if (mod->sect_attrs) {
 1408                 sysfs_remove_group(&mod->mkobj.kobj,
 1409                                    &mod->sect_attrs->grp);
 1410                 /* We are positive that no one is using any sect attrs
 1411                  * at this point.  Deallocate immediately. */
 1412                 free_sect_attrs(mod->sect_attrs);
 1413                 mod->sect_attrs = NULL;
 1414         }
 1415 }
 1416 
 1417 /*
 1418  * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
 1419  */
 1420 
 1421 struct module_notes_attrs {
 1422         struct kobject *dir;
 1423         unsigned int notes;
 1424         struct bin_attribute attrs[0];
 1425 };
 1426 
 1427 static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
 1428                                  struct bin_attribute *bin_attr,
 1429                                  char *buf, loff_t pos, size_t count)
 1430 {
 1431         /*
 1432          * The caller checked the pos and count against our size.
 1433          */
 1434         memcpy(buf, bin_attr->private + pos, count);
 1435         return count;
 1436 }
 1437 
 1438 static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
 1439                              unsigned int i)
 1440 {
 1441         if (notes_attrs->dir) {
 1442                 while (i-- > 0)
 1443                         sysfs_remove_bin_file(notes_attrs->dir,
 1444                                               &notes_attrs->attrs[i]);
 1445                 kobject_put(notes_attrs->dir);
 1446         }
 1447         kfree(notes_attrs);
 1448 }
 1449 
 1450 static void add_notes_attrs(struct module *mod, const struct load_info *info)
 1451 {
 1452         unsigned int notes, loaded, i;
 1453         struct module_notes_attrs *notes_attrs;
 1454         struct bin_attribute *nattr;
 1455 
 1456         /* failed to create section attributes, so can't create notes */
 1457         if (!mod->sect_attrs)
 1458                 return;
 1459 
 1460         /* Count notes sections and allocate structures.  */
 1461         notes = 0;
 1462         for (i = 0; i < info->hdr->e_shnum; i++)
 1463                 if (!sect_empty(&info->sechdrs[i]) &&
 1464                     (info->sechdrs[i].sh_type == SHT_NOTE))
 1465                         ++notes;
 1466 
 1467         if (notes == 0)
 1468                 return;
 1469 
 1470         notes_attrs = kzalloc(sizeof(*notes_attrs)
 1471                               + notes * sizeof(notes_attrs->attrs[0]),
 1472                               GFP_KERNEL);
 1473         if (notes_attrs == NULL)
 1474                 return;
 1475 
 1476         notes_attrs->notes = notes;
 1477         nattr = &notes_attrs->attrs[0];
 1478         for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
 1479                 if (sect_empty(&info->sechdrs[i]))
 1480                         continue;
 1481                 if (info->sechdrs[i].sh_type == SHT_NOTE) {
 1482                         sysfs_bin_attr_init(nattr);
 1483                         nattr->attr.name = mod->sect_attrs->attrs[loaded].name;
 1484                         nattr->attr.mode = S_IRUGO;
 1485                         nattr->size = info->sechdrs[i].sh_size;
 1486                         nattr->private = (void *) info->sechdrs[i].sh_addr;
 1487                         nattr->read = module_notes_read;
 1488                         ++nattr;
 1489                 }
 1490                 ++loaded;
 1491         }
 1492 
 1493         notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
 1494         if (!notes_attrs->dir)
 1495                 goto out;
 1496 
 1497         for (i = 0; i < notes; ++i)
 1498                 if (sysfs_create_bin_file(notes_attrs->dir,
 1499                                           &notes_attrs->attrs[i]))
 1500                         goto out;
 1501 
 1502         mod->notes_attrs = notes_attrs;
 1503         return;
 1504 
 1505   out:
 1506         free_notes_attrs(notes_attrs, i);
 1507 }
 1508 
 1509 static void remove_notes_attrs(struct module *mod)
 1510 {
 1511         if (mod->notes_attrs)
 1512                 free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
 1513 }
 1514 
 1515 #else
 1516 
 1517 static inline void add_sect_attrs(struct module *mod,
 1518                                   const struct load_info *info)
 1519 {
 1520 }
 1521 
 1522 static inline void remove_sect_attrs(struct module *mod)
 1523 {
 1524 }
 1525 
 1526 static inline void add_notes_attrs(struct module *mod,
 1527                                    const struct load_info *info)
 1528 {
 1529 }
 1530 
 1531 static inline void remove_notes_attrs(struct module *mod)
 1532 {
 1533 }
 1534 #endif /* CONFIG_KALLSYMS */
 1535 
 1536 static void add_usage_links(struct module *mod)
 1537 {
 1538 #ifdef CONFIG_MODULE_UNLOAD
 1539         struct module_use *use;
 1540         int nowarn;
 1541 
 1542         mutex_lock(&module_mutex);
 1543         list_for_each_entry(use, &mod->target_list, target_list) {
 1544                 nowarn = sysfs_create_link(use->target->holders_dir,
 1545                                            &mod->mkobj.kobj, mod->name);
 1546         }
 1547         mutex_unlock(&module_mutex);
 1548 #endif
 1549 }
 1550 
 1551 static void del_usage_links(struct module *mod)
 1552 {
 1553 #ifdef CONFIG_MODULE_UNLOAD
 1554         struct module_use *use;
 1555 
 1556         mutex_lock(&module_mutex);
 1557         list_for_each_entry(use, &mod->target_list, target_list)
 1558                 sysfs_remove_link(use->target->holders_dir, mod->name);
 1559         mutex_unlock(&module_mutex);
 1560 #endif
 1561 }
 1562 
 1563 static int module_add_modinfo_attrs(struct module *mod)
 1564 {
 1565         struct module_attribute *attr;
 1566         struct module_attribute *temp_attr;
 1567         int error = 0;
 1568         int i;
 1569 
 1570         mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
 1571                                         (ARRAY_SIZE(modinfo_attrs) + 1)),
 1572                                         GFP_KERNEL);
 1573         if (!mod->modinfo_attrs)
 1574                 return -ENOMEM;
 1575 
 1576         temp_attr = mod->modinfo_attrs;
 1577         for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
 1578                 if (!attr->test ||
 1579                     (attr->test && attr->test(mod))) {
 1580                         memcpy(temp_attr, attr, sizeof(*temp_attr));
 1581                         sysfs_attr_init(&temp_attr->attr);
 1582                         error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr);
 1583                         ++temp_attr;
 1584                 }
 1585         }
 1586         return error;
 1587 }
 1588 
 1589 static void module_remove_modinfo_attrs(struct module *mod)
 1590 {
 1591         struct module_attribute *attr;
 1592         int i;
 1593 
 1594         for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
 1595                 /* pick a field to test for end of list */
 1596                 if (!attr->attr.name)
 1597                         break;
 1598                 sysfs_remove_file(&mod->mkobj.kobj,&attr->attr);
 1599                 if (attr->free)
 1600                         attr->free(mod);
 1601         }
 1602         kfree(mod->modinfo_attrs);
 1603 }
 1604 
 1605 static int mod_sysfs_init(struct module *mod)
 1606 {
 1607         int err;
 1608         struct kobject *kobj;
 1609 
 1610         if (!module_sysfs_initialized) {
 1611                 printk(KERN_ERR "%s: module sysfs not initialized\n",
 1612                        mod->name);
 1613                 err = -EINVAL;
 1614                 goto out;
 1615         }
 1616 
 1617         kobj = kset_find_obj(module_kset, mod->name);
 1618         if (kobj) {
 1619                 printk(KERN_ERR "%s: module is already loaded\n", mod->name);
 1620                 kobject_put(kobj);
 1621                 err = -EINVAL;
 1622                 goto out;
 1623         }
 1624 
 1625         mod->mkobj.mod = mod;
 1626 
 1627         memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
 1628         mod->mkobj.kobj.kset = module_kset;
 1629         err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
 1630                                    "%s", mod->name);
 1631         if (err)
 1632                 kobject_put(&mod->mkobj.kobj);
 1633 
 1634         /* delay uevent until full sysfs population */
 1635 out:
 1636         return err;
 1637 }
 1638 
 1639 static int mod_sysfs_setup(struct module *mod,
 1640                            const struct load_info *info,
 1641                            struct kernel_param *kparam,
 1642                            unsigned int num_params)
 1643 {
 1644         int err;
 1645 
 1646         err = mod_sysfs_init(mod);
 1647         if (err)
 1648                 goto out;
 1649 
 1650         mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
 1651         if (!mod->holders_dir) {
 1652                 err = -ENOMEM;
 1653                 goto out_unreg;
 1654         }
 1655 
 1656         err = module_param_sysfs_setup(mod, kparam, num_params);
 1657         if (err)
 1658                 goto out_unreg_holders;
 1659 
 1660         err = module_add_modinfo_attrs(mod);
 1661         if (err)
 1662                 goto out_unreg_param;
 1663 
 1664         add_usage_links(mod);
 1665         add_sect_attrs(mod, info);
 1666         add_notes_attrs(mod, info);
 1667 
 1668         kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
 1669         return 0;
 1670 
 1671 out_unreg_param:
 1672         module_param_sysfs_remove(mod);
 1673 out_unreg_holders:
 1674         kobject_put(mod->holders_dir);
 1675 out_unreg:
 1676         kobject_put(&mod->mkobj.kobj);
 1677 out:
 1678         return err;
 1679 }
 1680 
 1681 static void mod_sysfs_fini(struct module *mod)
 1682 {
 1683         remove_notes_attrs(mod);
 1684         remove_sect_attrs(mod);
 1685         kobject_put(&mod->mkobj.kobj);
 1686 }
 1687 
 1688 #else /* !CONFIG_SYSFS */
 1689 
 1690 static int mod_sysfs_setup(struct module *mod,
 1691                            const struct load_info *info,
 1692                            struct kernel_param *kparam,
 1693                            unsigned int num_params)
 1694 {
 1695         return 0;
 1696 }
 1697 
 1698 static void mod_sysfs_fini(struct module *mod)
 1699 {
 1700 }
 1701 
 1702 static void module_remove_modinfo_attrs(struct module *mod)
 1703 {
 1704 }
 1705 
 1706 static void del_usage_links(struct module *mod)
 1707 {
 1708 }
 1709 
 1710 #endif /* CONFIG_SYSFS */
 1711 
 1712 static void mod_sysfs_teardown(struct module *mod)
 1713 {
 1714         del_usage_links(mod);
 1715         module_remove_modinfo_attrs(mod);
 1716         module_param_sysfs_remove(mod);
 1717         kobject_put(mod->mkobj.drivers_dir);
 1718         kobject_put(mod->holders_dir);
 1719         mod_sysfs_fini(mod);
 1720 }
 1721 
 1722 /*
 1723  * unlink the module with the whole machine is stopped with interrupts off
 1724  * - this defends against kallsyms not taking locks
 1725  */
 1726 static int __unlink_module(void *_mod)
 1727 {
 1728         struct module *mod = _mod;
 1729         list_del(&mod->list);
 1730         module_bug_cleanup(mod);
 1731         return 0;
 1732 }
 1733 
 1734 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 1735 /*
 1736  * LKM RO/NX protection: protect module's text/ro-data
 1737  * from modification and any data from execution.
 1738  */
 1739 void set_page_attributes(void *start, void *end, int (*set)(unsigned long start, int num_pages))
 1740 {
 1741         unsigned long begin_pfn = PFN_DOWN((unsigned long)start);
 1742         unsigned long end_pfn = PFN_DOWN((unsigned long)end);
 1743 
 1744         if (end_pfn > begin_pfn)
 1745                 set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
 1746 }
 1747 
 1748 static void set_section_ro_nx(void *base,
 1749                         unsigned long text_size,
 1750                         unsigned long ro_size,
 1751                         unsigned long total_size)
 1752 {
 1753         /* begin and end PFNs of the current subsection */
 1754         unsigned long begin_pfn;
 1755         unsigned long end_pfn;
 1756 
 1757         /*
 1758          * Set RO for module text and RO-data:
 1759          * - Always protect first page.
 1760          * - Do not protect last partial page.
 1761          */
 1762         if (ro_size > 0)
 1763                 set_page_attributes(base, base + ro_size, set_memory_ro);
 1764 
 1765         /*
 1766          * Set NX permissions for module data:
 1767          * - Do not protect first partial page.
 1768          * - Always protect last page.
 1769          */
 1770         if (total_size > text_size) {
 1771                 begin_pfn = PFN_UP((unsigned long)base + text_size);
 1772                 end_pfn = PFN_UP((unsigned long)base + total_size);
 1773                 if (end_pfn > begin_pfn)
 1774                         set_memory_nx(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
 1775         }
 1776 }
 1777 
 1778 static void unset_module_core_ro_nx(struct module *mod)
 1779 {
 1780         set_page_attributes(mod->module_core + mod->core_text_size,
 1781                 mod->module_core + mod->core_size,
 1782                 set_memory_x);
 1783         set_page_attributes(mod->module_core,
 1784                 mod->module_core + mod->core_ro_size,
 1785                 set_memory_rw);
 1786 }
 1787 
 1788 static void unset_module_init_ro_nx(struct module *mod)
 1789 {
 1790         set_page_attributes(mod->module_init + mod->init_text_size,
 1791                 mod->module_init + mod->init_size,
 1792                 set_memory_x);
 1793         set_page_attributes(mod->module_init,
 1794                 mod->module_init + mod->init_ro_size,
 1795                 set_memory_rw);
 1796 }
 1797 
 1798 /* Iterate through all modules and set each module's text as RW */
 1799 void set_all_modules_text_rw(void)
 1800 {
 1801         struct module *mod;
 1802 
 1803         mutex_lock(&module_mutex);
 1804         list_for_each_entry_rcu(mod, &modules, list) {
 1805                 if (mod->state == MODULE_STATE_UNFORMED)
 1806                         continue;
 1807                 if ((mod->module_core) && (mod->core_text_size)) {
 1808                         set_page_attributes(mod->module_core,
 1809                                                 mod->module_core + mod->core_text_size,
 1810                                                 set_memory_rw);
 1811                 }
 1812                 if ((mod->module_init) && (mod->init_text_size)) {
 1813                         set_page_attributes(mod->module_init,
 1814                                                 mod->module_init + mod->init_text_size,
 1815                                                 set_memory_rw);
 1816                 }
 1817         }
 1818         mutex_unlock(&module_mutex);
 1819 }
 1820 
 1821 /* Iterate through all modules and set each module's text as RO */
 1822 void set_all_modules_text_ro(void)
 1823 {
 1824         struct module *mod;
 1825 
 1826         mutex_lock(&module_mutex);
 1827         list_for_each_entry_rcu(mod, &modules, list) {
 1828                 if (mod->state == MODULE_STATE_UNFORMED)
 1829                         continue;
 1830                 if ((mod->module_core) && (mod->core_text_size)) {
 1831                         set_page_attributes(mod->module_core,
 1832                                                 mod->module_core + mod->core_text_size,
 1833                                                 set_memory_ro);
 1834                 }
 1835                 if ((mod->module_init) && (mod->init_text_size)) {
 1836                         set_page_attributes(mod->module_init,
 1837                                                 mod->module_init + mod->init_text_size,
 1838                                                 set_memory_ro);
 1839                 }
 1840         }
 1841         mutex_unlock(&module_mutex);
 1842 }
 1843 #else
 1844 static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { }
 1845 static void unset_module_core_ro_nx(struct module *mod) { }
 1846 static void unset_module_init_ro_nx(struct module *mod) { }
 1847 #endif
 1848 
 1849 void __weak module_free(struct module *mod, void *module_region)
 1850 {
 1851         vfree(module_region);
 1852 }
 1853 
 1854 void __weak module_arch_cleanup(struct module *mod)
 1855 {
 1856 }
 1857 
 1858 /* Free a module, remove from lists, etc. */
 1859 static void free_module(struct module *mod)
 1860 {
 1861         trace_module_free(mod);
 1862 
 1863         /* Delete from various lists */
 1864         mutex_lock(&module_mutex);
 1865         stop_machine(__unlink_module, mod, NULL);
 1866         mutex_unlock(&module_mutex);
 1867         mod_sysfs_teardown(mod);
 1868 
 1869         /* Remove dynamic debug info */
 1870         ddebug_remove_module(mod->name);
 1871 
 1872         /* Arch-specific cleanup. */
 1873         module_arch_cleanup(mod);
 1874 
 1875         /* Module unload stuff */
 1876         module_unload_free(mod);
 1877 
 1878         /* Free any allocated parameters. */
 1879         destroy_params(mod->kp, mod->num_kp);
 1880 
 1881         /* This may be NULL, but that's OK */
 1882         unset_module_init_ro_nx(mod);
 1883         module_free(mod, mod->module_init);
 1884         kfree(mod->args);
 1885         percpu_modfree(mod);
 1886 
 1887         /* Free lock-classes: */
 1888         lockdep_free_key_range(mod->module_core, mod->core_size);
 1889 
 1890         /* Finally, free the core (containing the module structure) */
 1891         unset_module_core_ro_nx(mod);
 1892         module_free(mod, mod->module_core);
 1893 
 1894 #ifdef CONFIG_MPU
 1895         update_protections(current->mm);
 1896 #endif
 1897 }
 1898 
 1899 void *__symbol_get(const char *symbol)
 1900 {
 1901         struct module *owner;
 1902         const struct kernel_symbol *sym;
 1903 
 1904         preempt_disable();
 1905         sym = find_symbol(symbol, &owner, NULL, true, true);
 1906         if (sym && strong_try_module_get(owner))
 1907                 sym = NULL;
 1908         preempt_enable();
 1909 
 1910         return sym ? (void *)sym->value : NULL;
 1911 }
 1912 EXPORT_SYMBOL_GPL(__symbol_get);
 1913 
 1914 /*
 1915  * Ensure that an exported symbol [global namespace] does not already exist
 1916  * in the kernel or in some other module's exported symbol table.
 1917  *
 1918  * You must hold the module_mutex.
 1919  */
 1920 static int verify_export_symbols(struct module *mod)
 1921 {
 1922         unsigned int i;
 1923         struct module *owner;
 1924         const struct kernel_symbol *s;
 1925         struct {
 1926                 const struct kernel_symbol *sym;
 1927                 unsigned int num;
 1928         } arr[] = {
 1929                 { mod->syms, mod->num_syms },
 1930                 { mod->gpl_syms, mod->num_gpl_syms },
 1931                 { mod->gpl_future_syms, mod->num_gpl_future_syms },
 1932 #ifdef CONFIG_UNUSED_SYMBOLS
 1933                 { mod->unused_syms, mod->num_unused_syms },
 1934                 { mod->unused_gpl_syms, mod->num_unused_gpl_syms },
 1935 #endif
 1936         };
 1937 
 1938         for (i = 0; i < ARRAY_SIZE(arr); i++) {
 1939                 for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
 1940                         if (find_symbol(s->name, &owner, NULL, true, false)) {
 1941                                 printk(KERN_ERR
 1942                                        "%s: exports duplicate symbol %s"
 1943                                        " (owned by %s)\n",
 1944                                        mod->name, s->name, module_name(owner));
 1945                                 return -ENOEXEC;
 1946                         }
 1947                 }
 1948         }
 1949         return 0;
 1950 }
 1951 
 1952 /* Change all symbols so that st_value encodes the pointer directly. */
 1953 static int simplify_symbols(struct module *mod, const struct load_info *info)
 1954 {
 1955         Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
 1956         Elf_Sym *sym = (void *)symsec->sh_addr;
 1957         unsigned long secbase;
 1958         unsigned int i;
 1959         int ret = 0;
 1960         const struct kernel_symbol *ksym;
 1961 
 1962         for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
 1963                 const char *name = info->strtab + sym[i].st_name;
 1964 
 1965                 switch (sym[i].st_shndx) {
 1966                 case SHN_COMMON:
 1967                         /* We compiled with -fno-common.  These are not
 1968                            supposed to happen.  */
 1969                         pr_debug("Common symbol: %s\n", name);
 1970                         printk("%s: please compile with -fno-common\n",
 1971                                mod->name);
 1972                         ret = -ENOEXEC;
 1973                         break;
 1974 
 1975                 case SHN_ABS:
 1976                         /* Don't need to do anything */
 1977                         pr_debug("Absolute symbol: 0x%08lx\n",
 1978                                (long)sym[i].st_value);
 1979                         break;
 1980 
 1981                 case SHN_UNDEF:
 1982                         ksym = resolve_symbol_wait(mod, info, name);
 1983                         /* Ok if resolved.  */
 1984                         if (ksym && !IS_ERR(ksym)) {
 1985                                 sym[i].st_value = ksym->value;
 1986                                 break;
 1987                         }
 1988 
 1989                         /* Ok if weak.  */
 1990                         if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
 1991                                 break;
 1992 
 1993                         printk(KERN_WARNING "%s: Unknown symbol %s (err %li)\n",
 1994                                mod->name, name, PTR_ERR(ksym));
 1995                         ret = PTR_ERR(ksym) ?: -ENOENT;
 1996                         break;
 1997 
 1998                 default:
 1999                         /* Divert to percpu allocation if a percpu var. */
 2000                         if (sym[i].st_shndx == info->index.pcpu)
 2001                                 secbase = (unsigned long)mod_percpu(mod);
 2002                         else
 2003                                 secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
 2004                         sym[i].st_value += secbase;
 2005                         break;
 2006                 }
 2007         }
 2008 
 2009         return ret;
 2010 }
 2011 
 2012 static int apply_relocations(struct module *mod, const struct load_info *info)
 2013 {
 2014         unsigned int i;
 2015         int err = 0;
 2016 
 2017         /* Now do relocations. */
 2018         for (i = 1; i < info->hdr->e_shnum; i++) {
 2019                 unsigned int infosec = info->sechdrs[i].sh_info;
 2020 
 2021                 /* Not a valid relocation section? */
 2022                 if (infosec >= info->hdr->e_shnum)
 2023                         continue;
 2024 
 2025                 /* Don't bother with non-allocated sections */
 2026                 if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
 2027                         continue;
 2028 
 2029                 if (info->sechdrs[i].sh_type == SHT_REL)
 2030                         err = apply_relocate(info->sechdrs, info->strtab,
 2031                                              info->index.sym, i, mod);
 2032                 else if (info->sechdrs[i].sh_type == SHT_RELA)
 2033                         err = apply_relocate_add(info->sechdrs, info->strtab,
 2034                                                  info->index.sym, i, mod);
 2035                 if (err < 0)
 2036                         break;
 2037         }
 2038         return err;
 2039 }
 2040 
 2041 /* Additional bytes needed by arch in front of individual sections */
 2042 unsigned int __weak arch_mod_section_prepend(struct module *mod,
 2043                                              unsigned int section)
 2044 {
 2045         /* default implementation just returns zero */
 2046         return 0;
 2047 }
 2048 
 2049 /* Update size with this section: return offset. */
 2050 static long get_offset(struct module *mod, unsigned int *size,
 2051                        Elf_Shdr *sechdr, unsigned int section)
 2052 {
 2053         long ret;
 2054 
 2055         *size += arch_mod_section_prepend(mod, section);
 2056         ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
 2057         *size = ret + sechdr->sh_size;
 2058         return ret;
 2059 }
 2060 
 2061 /* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
 2062    might -- code, read-only data, read-write data, small data.  Tally
 2063    sizes, and place the offsets into sh_entsize fields: high bit means it
 2064    belongs in init. */
 2065 static void layout_sections(struct module *mod, struct load_info *info)
 2066 {
 2067         static unsigned long const masks[][2] = {
 2068                 /* NOTE: all executable code must be the first section
 2069                  * in this array; otherwise modify the text_size
 2070                  * finder in the two loops below */
 2071                 { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
 2072                 { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
 2073                 { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
 2074                 { ARCH_SHF_SMALL | SHF_ALLOC, 0 }
 2075         };
 2076         unsigned int m, i;
 2077 
 2078         for (i = 0; i < info->hdr->e_shnum; i++)
 2079                 info->sechdrs[i].sh_entsize = ~0UL;
 2080 
 2081         pr_debug("Core section allocation order:\n");
 2082         for (m = 0; m < ARRAY_SIZE(masks); ++m) {
 2083                 for (i = 0; i < info->hdr->e_shnum; ++i) {
 2084                         Elf_Shdr *s = &info->sechdrs[i];
 2085                         const char *sname = info->secstrings + s->sh_name;
 2086 
 2087                         if ((s->sh_flags & masks[m][0]) != masks[m][0]
 2088                             || (s->sh_flags & masks[m][1])
 2089                             || s->sh_entsize != ~0UL
 2090                             || strstarts(sname, ".init"))
 2091                                 continue;
 2092                         s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
 2093                         pr_debug("\t%s\n", sname);
 2094                 }
 2095                 switch (m) {
 2096                 case 0: /* executable */
 2097                         mod->core_size = debug_align(mod->core_size);
 2098                         mod->core_text_size = mod->core_size;
 2099                         break;
 2100                 case 1: /* RO: text and ro-data */
 2101                         mod->core_size = debug_align(mod->core_size);
 2102                         mod->core_ro_size = mod->core_size;
 2103                         break;
 2104                 case 3: /* whole core */
 2105                         mod->core_size = debug_align(mod->core_size);
 2106                         break;
 2107                 }
 2108         }
 2109 
 2110         pr_debug("Init section allocation order:\n");
 2111         for (m = 0; m < ARRAY_SIZE(masks); ++m) {
 2112                 for (i = 0; i < info->hdr->e_shnum; ++i) {
 2113                         Elf_Shdr *s = &info->sechdrs[i];
 2114                         const char *sname = info->secstrings + s->sh_name;
 2115 
 2116                         if ((s->sh_flags & masks[m][0]) != masks[m][0]
 2117                             || (s->sh_flags & masks[m][1])
 2118                             || s->sh_entsize != ~0UL
 2119                             || !strstarts(sname, ".init"))
 2120                                 continue;
 2121                         s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
 2122                                          | INIT_OFFSET_MASK);
 2123                         pr_debug("\t%s\n", sname);
 2124                 }
 2125                 switch (m) {
 2126                 case 0: /* executable */
 2127                         mod->init_size = debug_align(mod->init_size);
 2128                         mod->init_text_size = mod->init_size;
 2129                         break;
 2130                 case 1: /* RO: text and ro-data */
 2131                         mod->init_size = debug_align(mod->init_size);
 2132                         mod->init_ro_size = mod->init_size;
 2133                         break;
 2134                 case 3: /* whole init */
 2135                         mod->init_size = debug_align(mod->init_size);
 2136                         break;
 2137                 }
 2138         }
 2139 }
 2140 
 2141 static void set_license(struct module *mod, const char *license)
 2142 {
 2143         if (!license)
 2144                 license = "unspecified";
 2145 
 2146         if (!license_is_gpl_compatible(license)) {
 2147                 if (!test_taint(TAINT_PROPRIETARY_MODULE))
 2148                         printk(KERN_WARNING "%s: module license '%s' taints "
 2149                                 "kernel.\n", mod->name, license);
 2150                 add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
 2151         }
 2152 }
 2153 
 2154 /* Parse tag=value strings from .modinfo section */
 2155 static char *next_string(char *string, unsigned long *secsize)
 2156 {
 2157         /* Skip non-zero chars */
 2158         while (string[0]) {
 2159                 string++;
 2160                 if ((*secsize)-- <= 1)
 2161                         return NULL;
 2162         }
 2163 
 2164         /* Skip any zero padding. */
 2165         while (!string[0]) {
 2166                 string++;
 2167                 if ((*secsize)-- <= 1)
 2168                         return NULL;
 2169         }
 2170         return string;
 2171 }
 2172 
 2173 static char *get_modinfo(struct load_info *info, const char *tag)
 2174 {
 2175         char *p;
 2176         unsigned int taglen = strlen(tag);
 2177         Elf_Shdr *infosec = &info->sechdrs[info->index.info];
 2178         unsigned long size = infosec->sh_size;
 2179 
 2180         for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {
 2181                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 2182                         return p + taglen + 1;
 2183         }
 2184         return NULL;
 2185 }
 2186 
 2187 static void setup_modinfo(struct module *mod, struct load_info *info)
 2188 {
 2189         struct module_attribute *attr;
 2190         int i;
 2191 
 2192         for (i = 0; (attr = modinfo_attrs[i]); i++) {
 2193                 if (attr->setup)
 2194                         attr->setup(mod, get_modinfo(info, attr->attr.name));
 2195         }
 2196 }
 2197 
 2198 static void free_modinfo(struct module *mod)
 2199 {
 2200         struct module_attribute *attr;
 2201         int i;
 2202 
 2203         for (i = 0; (attr = modinfo_attrs[i]); i++) {
 2204                 if (attr->free)
 2205                         attr->free(mod);
 2206         }
 2207 }
 2208 
 2209 #ifdef CONFIG_KALLSYMS
 2210 
 2211 /* lookup symbol in given range of kernel_symbols */
 2212 static const struct kernel_symbol *lookup_symbol(const char *name,
 2213         const struct kernel_symbol *start,
 2214         const struct kernel_symbol *stop)
 2215 {
 2216         return bsearch(name, start, stop - start,
 2217                         sizeof(struct kernel_symbol), cmp_name);
 2218 }
 2219 
 2220 static int is_exported(const char *name, unsigned long value,
 2221                        const struct module *mod)
 2222 {
 2223         const struct kernel_symbol *ks;
 2224         if (!mod)
 2225                 ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
 2226         else
 2227                 ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
 2228         return ks != NULL && ks->value == value;
 2229 }
 2230 
 2231 /* As per nm */
 2232 static char elf_type(const Elf_Sym *sym, const struct load_info *info)
 2233 {
 2234         const Elf_Shdr *sechdrs = info->sechdrs;
 2235 
 2236         if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
 2237                 if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
 2238                         return 'v';
 2239                 else
 2240                         return 'w';
 2241         }
 2242         if (sym->st_shndx == SHN_UNDEF)
 2243                 return 'U';
 2244         if (sym->st_shndx == SHN_ABS)
 2245                 return 'a';
 2246         if (sym->st_shndx >= SHN_LORESERVE)
 2247                 return '?';
 2248         if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
 2249                 return 't';
 2250         if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
 2251             && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
 2252                 if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
 2253                         return 'r';
 2254                 else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
 2255                         return 'g';
 2256                 else
 2257                         return 'd';
 2258         }
 2259         if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
 2260                 if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
 2261                         return 's';
 2262                 else
 2263                         return 'b';
 2264         }
 2265         if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
 2266                       ".debug")) {
 2267                 return 'n';
 2268         }
 2269         return '?';
 2270 }
 2271 
 2272 static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
 2273                            unsigned int shnum)
 2274 {
 2275         const Elf_Shdr *sec;
 2276 
 2277         if (src->st_shndx == SHN_UNDEF
 2278             || src->st_shndx >= shnum
 2279             || !src->st_name)
 2280                 return false;
 2281 
 2282         sec = sechdrs + src->st_shndx;
 2283         if (!(sec->sh_flags & SHF_ALLOC)
 2284 #ifndef CONFIG_KALLSYMS_ALL
 2285             || !(sec->sh_flags & SHF_EXECINSTR)
 2286 #endif
 2287             || (sec->sh_entsize & INIT_OFFSET_MASK))
 2288                 return false;
 2289 
 2290         return true;
 2291 }
 2292 
 2293 /*
 2294  * We only allocate and copy the strings needed by the parts of symtab
 2295  * we keep.  This is simple, but has the effect of making multiple
 2296  * copies of duplicates.  We could be more sophisticated, see
 2297  * linux-kernel thread starting with
 2298  * <73defb5e4bca04a6431392cc341112b1@localhost>.
 2299  */
 2300 static void layout_symtab(struct module *mod, struct load_info *info)
 2301 {
 2302         Elf_Shdr *symsect = info->sechdrs + info->index.sym;
 2303         Elf_Shdr *strsect = info->sechdrs + info->index.str;
 2304         const Elf_Sym *src;
 2305         unsigned int i, nsrc, ndst, strtab_size = 0;
 2306 
 2307         /* Put symbol section at end of init part of module. */
 2308         symsect->sh_flags |= SHF_ALLOC;
 2309         symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
 2310                                          info->index.sym) | INIT_OFFSET_MASK;
 2311         pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
 2312 
 2313         src = (void *)info->hdr + symsect->sh_offset;
 2314         nsrc = symsect->sh_size / sizeof(*src);
 2315 
 2316         /* Compute total space required for the core symbols' strtab. */
 2317         for (ndst = i = 0; i < nsrc; i++) {
 2318                 if (i == 0 ||
 2319                     is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
 2320                         strtab_size += strlen(&info->strtab[src[i].st_name])+1;
 2321                         ndst++;
 2322                 }
 2323         }
 2324 
 2325         /* Append room for core symbols at end of core part. */
 2326         info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
 2327         info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
 2328         mod->core_size += strtab_size;
 2329 
 2330         /* Put string table section at end of init part of module. */
 2331         strsect->sh_flags |= SHF_ALLOC;
 2332         strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
 2333                                          info->index.str) | INIT_OFFSET_MASK;
 2334         pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
 2335 }
 2336 
 2337 static void add_kallsyms(struct module *mod, const struct load_info *info)
 2338 {
 2339         unsigned int i, ndst;
 2340         const Elf_Sym *src;
 2341         Elf_Sym *dst;
 2342         char *s;
 2343         Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
 2344 
 2345         mod->symtab = (void *)symsec->sh_addr;
 2346         mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
 2347         /* Make sure we get permanent strtab: don't use info->strtab. */
 2348         mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
 2349 
 2350         /* Set types up while we still have access to sections. */
 2351         for (i = 0; i < mod->num_symtab; i++)
 2352                 mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);
 2353 
 2354         mod->core_symtab = dst = mod->module_core + info->symoffs;
 2355         mod->core_strtab = s = mod->module_core + info->stroffs;
 2356         src = mod->symtab;
 2357         for (ndst = i = 0; i < mod->num_symtab; i++) {
 2358                 if (i == 0 ||
 2359                     is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) {
 2360                         dst[ndst] = src[i];
 2361                         dst[ndst++].st_name = s - mod->core_strtab;
 2362                         s += strlcpy(s, &mod->strtab[src[i].st_name],
 2363                                      KSYM_NAME_LEN) + 1;
 2364                 }
 2365         }
 2366         mod->core_num_syms = ndst;
 2367 }
 2368 #else
 2369 static inline void layout_symtab(struct module *mod, struct load_info *info)
 2370 {
 2371 }
 2372 
 2373 static void add_kallsyms(struct module *mod, const struct load_info *info)
 2374 {
 2375 }
 2376 #endif /* CONFIG_KALLSYMS */
 2377 
 2378 static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
 2379 {
 2380         if (!debug)
 2381                 return;
 2382 #ifdef CONFIG_DYNAMIC_DEBUG
 2383         if (ddebug_add_module(debug, num, debug->modname))
 2384                 printk(KERN_ERR "dynamic debug error adding module: %s\n",
 2385                                         debug->modname);
 2386 #endif
 2387 }
 2388 
 2389 static void dynamic_debug_remove(struct _ddebug *debug)
 2390 {
 2391         if (debug)
 2392                 ddebug_remove_module(debug->modname);
 2393 }
 2394 
 2395 void * __weak module_alloc(unsigned long size)
 2396 {
 2397         return vmalloc_exec(size);
 2398 }
 2399 
 2400 static void *module_alloc_update_bounds(unsigned long size)
 2401 {
 2402         void *ret = module_alloc(size);
 2403 
 2404         if (ret) {
 2405                 mutex_lock(&module_mutex);
 2406                 /* Update module bounds. */
 2407                 if ((unsigned long)ret < module_addr_min)
 2408                         module_addr_min = (unsigned long)ret;
 2409                 if ((unsigned long)ret + size > module_addr_max)
 2410                         module_addr_max = (unsigned long)ret + size;
 2411                 mutex_unlock(&module_mutex);
 2412         }
 2413         return ret;
 2414 }
 2415 
 2416 #ifdef CONFIG_DEBUG_KMEMLEAK
 2417 static void kmemleak_load_module(const struct module *mod,
 2418                                  const struct load_info *info)
 2419 {
 2420         unsigned int i;
 2421 
 2422         /* only scan the sections containing data */
 2423         kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
 2424 
 2425         for (i = 1; i < info->hdr->e_shnum; i++) {
 2426                 const char *name = info->secstrings + info->sechdrs[i].sh_name;
 2427                 if (!(info->sechdrs[i].sh_flags & SHF_ALLOC))
 2428                         continue;
 2429                 if (!strstarts(name, ".data") && !strstarts(name, ".bss"))
 2430                         continue;
 2431 
 2432                 kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
 2433                                    info->sechdrs[i].sh_size, GFP_KERNEL);
 2434         }
 2435 }
 2436 #else
 2437 static inline void kmemleak_load_module(const struct module *mod,
 2438                                         const struct load_info *info)
 2439 {
 2440 }
 2441 #endif
 2442 
 2443 #ifdef CONFIG_MODULE_SIG
 2444 static int module_sig_check(struct load_info *info)
 2445 {
 2446         int err = -ENOKEY;
 2447         const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
 2448         const void *mod = info->hdr;
 2449 
 2450         if (info->len > markerlen &&
 2451             memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
 2452                 /* We truncate the module to discard the signature */
 2453                 info->len -= markerlen;
 2454                 err = mod_verify_sig(mod, &info->len);
 2455         }
 2456 
 2457         if (!err) {
 2458                 info->sig_ok = true;
 2459                 return 0;
 2460         }
 2461 
 2462         /* Not having a signature is only an error if we're strict. */
 2463         if (err < 0 && fips_enabled)
 2464                 panic("Module verification failed with error %d in FIPS mode\n",
 2465                       err);
 2466         if (err == -ENOKEY && !sig_enforce)
 2467                 err = 0;
 2468 
 2469         return err;
 2470 }
 2471 #else /* !CONFIG_MODULE_SIG */
 2472 static int module_sig_check(struct load_info *info)
 2473 {
 2474         return 0;
 2475 }
 2476 #endif /* !CONFIG_MODULE_SIG */
 2477 
 2478 /* Sanity checks against invalid binaries, wrong arch, weird elf version. */
 2479 static int elf_header_check(struct load_info *info)
 2480 {
 2481         if (info->len < sizeof(*(info->hdr)))
 2482                 return -ENOEXEC;
 2483 
 2484         if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0
 2485             || info->hdr->e_type != ET_REL
 2486             || !elf_check_arch(info->hdr)
 2487             || info->hdr->e_shentsize != sizeof(Elf_Shdr))
 2488                 return -ENOEXEC;
 2489 
 2490         if (info->hdr->e_shoff >= info->len
 2491             || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
 2492                 info->len - info->hdr->e_shoff))
 2493                 return -ENOEXEC;
 2494 
 2495         return 0;
 2496 }
 2497 
 2498 /* Sets info->hdr and info->len. */
 2499 static int copy_module_from_user(const void __user *umod, unsigned long len,
 2500                                   struct load_info *info)
 2501 {
 2502         int err;
 2503 
 2504         info->len = len;
 2505         if (info->len < sizeof(*(info->hdr)))
 2506                 return -ENOEXEC;
 2507 
 2508         err = security_kernel_module_from_file(NULL);
 2509         if (err)
 2510                 return err;
 2511 
 2512         /* Suck in entire file: we'll want most of it. */
 2513         info->hdr = vmalloc(info->len);
 2514         if (!info->hdr)
 2515                 return -ENOMEM;
 2516 
 2517         if (copy_from_user(info->hdr, umod, info->len) != 0) {
 2518                 vfree(info->hdr);
 2519                 return -EFAULT;
 2520         }
 2521 
 2522         return 0;
 2523 }
 2524 
 2525 /* Sets info->hdr and info->len. */
 2526 static int copy_module_from_fd(int fd, struct load_info *info)
 2527 {
 2528         struct file *file;
 2529         int err;
 2530         struct kstat stat;
 2531         loff_t pos;
 2532         ssize_t bytes = 0;
 2533 
 2534         file = fget(fd);
 2535         if (!file)
 2536                 return -ENOEXEC;
 2537 
 2538         err = security_kernel_module_from_file(file);
 2539         if (err)
 2540                 goto out;
 2541 
 2542         err = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat);
 2543         if (err)
 2544                 goto out;
 2545 
 2546         if (stat.size > INT_MAX) {
 2547                 err = -EFBIG;
 2548                 goto out;
 2549         }
 2550 
 2551         /* Don't hand 0 to vmalloc, it whines. */
 2552         if (stat.size == 0) {
 2553                 err = -EINVAL;
 2554                 goto out;
 2555         }
 2556 
 2557         info->hdr = vmalloc(stat.size);
 2558         if (!info->hdr) {
 2559                 err = -ENOMEM;
 2560                 goto out;
 2561         }
 2562 
 2563         pos = 0;
 2564         while (pos < stat.size) {
 2565                 bytes = kernel_read(file, pos, (char *)(info->hdr) + pos,
 2566                                     stat.size - pos);
 2567                 if (bytes < 0) {
 2568                         vfree(info->hdr);
 2569                         err = bytes;
 2570                         goto out;
 2571                 }
 2572                 if (bytes == 0)
 2573                         break;
 2574                 pos += bytes;
 2575         }
 2576         info->len = pos;
 2577 
 2578 out:
 2579         fput(file);
 2580         return err;
 2581 }
 2582 
 2583 static void free_copy(struct load_info *info)
 2584 {
 2585         vfree(info->hdr);
 2586 }
 2587 
 2588 static int rewrite_section_headers(struct load_info *info, int flags)
 2589 {
 2590         unsigned int i;
 2591 
 2592         /* This should always be true, but let's be sure. */
 2593         info->sechdrs[0].sh_addr = 0;
 2594 
 2595         for (i = 1; i < info->hdr->e_shnum; i++) {
 2596                 Elf_Shdr *shdr = &info->sechdrs[i];
 2597                 if (shdr->sh_type != SHT_NOBITS
 2598                     && info->len < shdr->sh_offset + shdr->sh_size) {
 2599                         printk(KERN_ERR "Module len %lu truncated\n",
 2600                                info->len);
 2601                         return -ENOEXEC;
 2602                 }
 2603 
 2604                 /* Mark all sections sh_addr with their address in the
 2605                    temporary image. */
 2606                 shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
 2607 
 2608 #ifndef CONFIG_MODULE_UNLOAD
 2609                 /* Don't load .exit sections */
 2610                 if (strstarts(info->secstrings+shdr->sh_name, ".exit"))
 2611                         shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
 2612 #endif
 2613         }
 2614 
 2615         /* Track but don't keep modinfo and version sections. */
 2616         if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
 2617                 info->index.vers = 0; /* Pretend no __versions section! */
 2618         else
 2619                 info->index.vers = find_sec(info, "__versions");
 2620         info->index.info = find_sec(info, ".modinfo");
 2621         info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
 2622         info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
 2623         return 0;
 2624 }
 2625 
 2626 /*
 2627  * Set up our basic convenience variables (pointers to section headers,
 2628  * search for module section index etc), and do some basic section
 2629  * verification.
 2630  *
 2631  * Return the temporary module pointer (we'll replace it with the final
 2632  * one when we move the module sections around).
 2633  */
 2634 static struct module *setup_load_info(struct load_info *info, int flags)
 2635 {
 2636         unsigned int i;
 2637         int err;
 2638         struct module *mod;
 2639 
 2640         /* Set up the convenience variables */
 2641         info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
 2642         info->secstrings = (void *)info->hdr
 2643                 + info->sechdrs[info->hdr->e_shstrndx].sh_offset;
 2644 
 2645         err = rewrite_section_headers(info, flags);
 2646         if (err)
 2647                 return ERR_PTR(err);
 2648 
 2649         /* Find internal symbols and strings. */
 2650         for (i = 1; i < info->hdr->e_shnum; i++) {
 2651                 if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
 2652                         info->index.sym = i;
 2653                         info->index.str = info->sechdrs[i].sh_link;
 2654                         info->strtab = (char *)info->hdr
 2655                                 + info->sechdrs[info->index.str].sh_offset;
 2656                         break;
 2657                 }
 2658         }
 2659 
 2660         info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
 2661         if (!info->index.mod) {
 2662                 printk(KERN_WARNING "No module found in object\n");
 2663                 return ERR_PTR(-ENOEXEC);
 2664         }
 2665         /* This is temporary: point mod into copy of data. */
 2666         mod = (void *)info->sechdrs[info->index.mod].sh_addr;
 2667 
 2668         if (info->index.sym == 0) {
 2669                 printk(KERN_WARNING "%s: module has no symbols (stripped?)\n",
 2670                        mod->name);
 2671                 return ERR_PTR(-ENOEXEC);
 2672         }
 2673 
 2674         info->index.pcpu = find_pcpusec(info);
 2675 
 2676         /* Check module struct version now, before we try to use module. */
 2677         if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
 2678                 return ERR_PTR(-ENOEXEC);
 2679 
 2680         return mod;
 2681 }
 2682 
 2683 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 2684 {
 2685         const char *modmagic = get_modinfo(info, "vermagic");
 2686         int err;
 2687 
 2688         if (flags & MODULE_INIT_IGNORE_VERMAGIC)
 2689                 modmagic = NULL;
 2690 
 2691         /* This is allowed: modprobe --force will invalidate it. */
 2692         if (!modmagic) {
 2693                 err = try_to_force_load(mod, "bad vermagic");
 2694                 if (err)
 2695                         return err;
 2696         } else if (!same_magic(modmagic, vermagic, info->index.vers)) {
 2697                 printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
 2698                        mod->name, modmagic, vermagic);
 2699                 return -ENOEXEC;
 2700         }
 2701 
 2702         if (!get_modinfo(info, "intree"))
 2703                 add_taint_module(mod, TAINT_OOT_MODULE);
 2704 
 2705         if (get_modinfo(info, "staging")) {
 2706                 add_taint_module(mod, TAINT_CRAP);
 2707                 printk(KERN_WARNING "%s: module is from the staging directory,"
 2708                        " the quality is unknown, you have been warned.\n",
 2709                        mod->name);
 2710         }
 2711 
 2712         /* Set up license info based on the info section */
 2713         set_license(mod, get_modinfo(info, "license"));
 2714 
 2715         return 0;
 2716 }
 2717 
 2718 static void find_module_sections(struct module *mod, struct load_info *info)
 2719 {
 2720         mod->kp = section_objs(info, "__param",
 2721                                sizeof(*mod->kp), &mod->num_kp);
 2722         mod->syms = section_objs(info, "__ksymtab",
 2723                                  sizeof(*mod->syms), &mod->num_syms);
 2724         mod->crcs = section_addr(info, "__kcrctab");
 2725         mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
 2726                                      sizeof(*mod->gpl_syms),
 2727                                      &mod->num_gpl_syms);
 2728         mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
 2729         mod->gpl_future_syms = section_objs(info,
 2730                                             "__ksymtab_gpl_future",
 2731                                             sizeof(*mod->gpl_future_syms),
 2732                                             &mod->num_gpl_future_syms);
 2733         mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
 2734 
 2735 #ifdef CONFIG_UNUSED_SYMBOLS
 2736         mod->unused_syms = section_objs(info, "__ksymtab_unused",
 2737                                         sizeof(*mod->unused_syms),
 2738                                         &mod->num_unused_syms);
 2739         mod->unused_crcs = section_addr(info, "__kcrctab_unused");
 2740         mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
 2741                                             sizeof(*mod->unused_gpl_syms),
 2742                                             &mod->num_unused_gpl_syms);
 2743         mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
 2744 #endif
 2745 #ifdef CONFIG_CONSTRUCTORS
 2746         mod->ctors = section_objs(info, ".ctors",
 2747                                   sizeof(*mod->ctors), &mod->num_ctors);
 2748 #endif
 2749 
 2750 #ifdef CONFIG_TRACEPOINTS
 2751         mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
 2752                                              sizeof(*mod->tracepoints_ptrs),
 2753                                              &mod->num_tracepoints);
 2754 #endif
 2755 #ifdef HAVE_JUMP_LABEL
 2756         mod->jump_entries = section_objs(info, "__jump_table",
 2757                                         sizeof(*mod->jump_entries),
 2758                                         &mod->num_jump_entries);
 2759 #endif
 2760 #ifdef CONFIG_EVENT_TRACING
 2761         mod->trace_events = section_objs(info, "_ftrace_events",
 2762                                          sizeof(*mod->trace_events),
 2763                                          &mod->num_trace_events);
 2764         /*
 2765          * This section contains pointers to allocated objects in the trace
 2766          * code and not scanning it leads to false positives.
 2767          */
 2768         kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
 2769                            mod->num_trace_events, GFP_KERNEL);
 2770 #endif
 2771 #ifdef CONFIG_TRACING
 2772         mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
 2773                                          sizeof(*mod->trace_bprintk_fmt_start),
 2774                                          &mod->num_trace_bprintk_fmt);
 2775         /*
 2776          * This section contains pointers to allocated objects in the trace
 2777          * code and not scanning it leads to false positives.
 2778          */
 2779         kmemleak_scan_area(mod->trace_bprintk_fmt_start,
 2780                            sizeof(*mod->trace_bprintk_fmt_start) *
 2781                            mod->num_trace_bprintk_fmt, GFP_KERNEL);
 2782 #endif
 2783 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 2784         /* sechdrs[0].sh_size is always zero */
 2785         mod->ftrace_callsites = section_objs(info, "__mcount_loc",
 2786                                              sizeof(*mod->ftrace_callsites),
 2787                                              &mod->num_ftrace_callsites);
 2788 #endif
 2789 
 2790         mod->extable = section_objs(info, "__ex_table",
 2791                                     sizeof(*mod->extable), &mod->num_exentries);
 2792 
 2793         if (section_addr(info, "__obsparm"))
 2794                 printk(KERN_WARNING "%s: Ignoring obsolete parameters\n",
 2795                        mod->name);
 2796 
 2797         info->debug = section_objs(info, "__verbose",
 2798                                    sizeof(*info->debug), &info->num_debug);
 2799 }
 2800 
 2801 static int move_module(struct module *mod, struct load_info *info)
 2802 {
 2803         int i;
 2804         void *ptr;
 2805 
 2806         /* Do the allocs. */
 2807         ptr = module_alloc_update_bounds(mod->core_size);
 2808         /*
 2809          * The pointer to this block is stored in the module structure
 2810          * which is inside the block. Just mark it as not being a
 2811          * leak.
 2812          */
 2813         kmemleak_not_leak(ptr);
 2814         if (!ptr)
 2815                 return -ENOMEM;
 2816 
 2817         memset(ptr, 0, mod->core_size);
 2818         mod->module_core = ptr;
 2819 
 2820         if (mod->init_size) {
 2821                 ptr = module_alloc_update_bounds(mod->init_size);
 2822                 /*
 2823                  * The pointer to this block is stored in the module structure
 2824                  * which is inside the block. This block doesn't need to be
 2825                  * scanned as it contains data and code that will be freed
 2826                  * after the module is initialized.
 2827                  */
 2828                 kmemleak_ignore(ptr);
 2829                 if (!ptr) {
 2830                         module_free(mod, mod->module_core);
 2831                         return -ENOMEM;
 2832                 }
 2833                 memset(ptr, 0, mod->init_size);
 2834                 mod->module_init = ptr;
 2835         } else
 2836                 mod->module_init = NULL;
 2837 
 2838         /* Transfer each section which specifies SHF_ALLOC */
 2839         pr_debug("final section addresses:\n");
 2840         for (i = 0; i < info->hdr->e_shnum; i++) {
 2841                 void *dest;
 2842                 Elf_Shdr *shdr = &info->sechdrs[i];
 2843 
 2844                 if (!(shdr->sh_flags & SHF_ALLOC))
 2845                         continue;
 2846 
 2847                 if (shdr->sh_entsize & INIT_OFFSET_MASK)
 2848                         dest = mod->module_init
 2849                                 + (shdr->sh_entsize & ~INIT_OFFSET_MASK);
 2850                 else
 2851                         dest = mod->module_core + shdr->sh_entsize;
 2852 
 2853                 if (shdr->sh_type != SHT_NOBITS)
 2854                         memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
 2855                 /* Update sh_addr to point to copy in image. */
 2856                 shdr->sh_addr = (unsigned long)dest;
 2857                 pr_debug("\t0x%lx %s\n",
 2858                          (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
 2859         }
 2860 
 2861         return 0;
 2862 }
 2863 
 2864 static int check_module_license_and_versions(struct module *mod)
 2865 {
 2866         /*
 2867          * ndiswrapper is under GPL by itself, but loads proprietary modules.
 2868          * Don't use add_taint_module(), as it would prevent ndiswrapper from
 2869          * using GPL-only symbols it needs.
 2870          */
 2871         if (strcmp(mod->name, "ndiswrapper") == 0)
 2872                 add_taint(TAINT_PROPRIETARY_MODULE);
 2873 
 2874         /* driverloader was caught wrongly pretending to be under GPL */
 2875         if (strcmp(mod->name, "driverloader") == 0)
 2876                 add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
 2877 
 2878         /* lve claims to be GPL but upstream won't provide source */
 2879         if (strcmp(mod->name, "lve") == 0)
 2880                 add_taint_module(mod, TAINT_PROPRIETARY_MODULE);
 2881 
 2882 #ifdef CONFIG_MODVERSIONS
 2883         if ((mod->num_syms && !mod->crcs)
 2884             || (mod->num_gpl_syms && !mod->gpl_crcs)
 2885             || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
 2886 #ifdef CONFIG_UNUSED_SYMBOLS
 2887             || (mod->num_unused_syms && !mod->unused_crcs)
 2888             || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
 2889 #endif
 2890                 ) {
 2891                 return try_to_force_load(mod,
 2892                                          "no versions for exported symbols");
 2893         }
 2894 #endif
 2895         return 0;
 2896 }
 2897 
 2898 static void flush_module_icache(const struct module *mod)
 2899 {
 2900         mm_segment_t old_fs;
 2901 
 2902         /* flush the icache in correct context */
 2903         old_fs = get_fs();
 2904         set_fs(KERNEL_DS);
 2905 
 2906         /*
 2907          * Flush the instruction cache, since we've played with text.
 2908          * Do it before processing of module parameters, so the module
 2909          * can provide parameter accessor functions of its own.
 2910          */
 2911         if (mod->module_init)
 2912                 flush_icache_range((unsigned long)mod->module_init,
 2913                                    (unsigned long)mod->module_init
 2914                                    + mod->init_size);
 2915         flush_icache_range((unsigned long)mod->module_core,
 2916                            (unsigned long)mod->module_core + mod->core_size);
 2917 
 2918         set_fs(old_fs);
 2919 }
 2920 
 2921 int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
 2922                                      Elf_Shdr *sechdrs,
 2923                                      char *secstrings,
 2924                                      struct module *mod)
 2925 {
 2926         return 0;
 2927 }
 2928 
 2929 static struct module *layout_and_allocate(struct load_info *info, int flags)
 2930 {
 2931         /* Module within temporary copy. */
 2932         struct module *mod;
 2933         Elf_Shdr *pcpusec;
 2934         int err;
 2935 
 2936         mod = setup_load_info(info, flags);
 2937         if (IS_ERR(mod))
 2938                 return mod;
 2939 
 2940         err = check_modinfo(mod, info, flags);
 2941         if (err)
 2942                 return ERR_PTR(err);
 2943 
 2944         /* Allow arches to frob section contents and sizes.  */
 2945         err = module_frob_arch_sections(info->hdr, info->sechdrs,
 2946                                         info->secstrings, mod);
 2947         if (err < 0)
 2948                 goto out;
 2949 
 2950         pcpusec = &info->sechdrs[info->index.pcpu];
 2951         if (pcpusec->sh_size) {
 2952                 /* We have a special allocation for this section. */
 2953                 err = percpu_modalloc(mod,
 2954                                       pcpusec->sh_size, pcpusec->sh_addralign);
 2955                 if (err)
 2956                         goto out;
 2957                 pcpusec->sh_flags &= ~(unsigned long)SHF_ALLOC;
 2958         }
 2959 
 2960         /* Determine total sizes, and put offsets in sh_entsize.  For now
 2961            this is done generically; there doesn't appear to be any
 2962            special cases for the architectures. */
 2963         layout_sections(mod, info);
 2964         layout_symtab(mod, info);
 2965 
 2966         /* Allocate and move to the final place */
 2967         err = move_module(mod, info);
 2968         if (err)
 2969                 goto free_percpu;
 2970 
 2971         /* Module has been copied to its final place now: return it. */
 2972         mod = (void *)info->sechdrs[info->index.mod].sh_addr;
 2973         kmemleak_load_module(mod, info);
 2974         return mod;
 2975 
 2976 free_percpu:
 2977         percpu_modfree(mod);
 2978 out:
 2979         return ERR_PTR(err);
 2980 }
 2981 
 2982 /* mod is no longer valid after this! */
 2983 static void module_deallocate(struct module *mod, struct load_info *info)
 2984 {
 2985         percpu_modfree(mod);
 2986         module_free(mod, mod->module_init);
 2987         module_free(mod, mod->module_core);
 2988 }
 2989 
 2990 int __weak module_finalize(const Elf_Ehdr *hdr,
 2991                            const Elf_Shdr *sechdrs,
 2992                            struct module *me)
 2993 {
 2994         return 0;
 2995 }
 2996 
 2997 static int post_relocation(struct module *mod, const struct load_info *info)
 2998 {
 2999         /* Sort exception table now relocations are done. */
 3000         sort_extable(mod->extable, mod->extable + mod->num_exentries);
 3001 
 3002         /* Copy relocated percpu area over. */
 3003         percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
 3004                        info->sechdrs[info->index.pcpu].sh_size);
 3005 
 3006         /* Setup kallsyms-specific fields. */
 3007         add_kallsyms(mod, info);
 3008 
 3009         /* Arch-specific module finalizing. */
 3010         return module_finalize(info->hdr, info->sechdrs, mod);
 3011 }
 3012 
 3013 /* Is this module of this name done loading?  No locks held. */
 3014 static bool finished_loading(const char *name)
 3015 {
 3016         struct module *mod;
 3017         bool ret;
 3018 
 3019         mutex_lock(&module_mutex);
 3020         mod = find_module_all(name, true);
 3021         ret = !mod || mod->state == MODULE_STATE_LIVE
 3022                 || mod->state == MODULE_STATE_GOING;
 3023         mutex_unlock(&module_mutex);
 3024 
 3025         return ret;
 3026 }
 3027 
 3028 /* Call module constructors. */
 3029 static void do_mod_ctors(struct module *mod)
 3030 {
 3031 #ifdef CONFIG_CONSTRUCTORS
 3032         unsigned long i;
 3033 
 3034         for (i = 0; i < mod->num_ctors; i++)
 3035                 mod->ctors[i]();
 3036 #endif
 3037 }
 3038 
 3039 /* This is where the real work happens */
 3040 static int do_init_module(struct module *mod)
 3041 {
 3042         int ret = 0;
 3043 
 3044         /*
 3045          * We want to find out whether @mod uses async during init.  Clear
 3046          * PF_USED_ASYNC.  async_schedule*() will set it.
 3047          */
 3048         current->flags &= ~PF_USED_ASYNC;
 3049 
 3050         blocking_notifier_call_chain(&module_notify_list,
 3051                         MODULE_STATE_COMING, mod);
 3052 
 3053         /* Set RO and NX regions for core */
 3054         set_section_ro_nx(mod->module_core,
 3055                                 mod->core_text_size,
 3056                                 mod->core_ro_size,
 3057                                 mod->core_size);
 3058 
 3059         /* Set RO and NX regions for init */
 3060         set_section_ro_nx(mod->module_init,
 3061                                 mod->init_text_size,
 3062                                 mod->init_ro_size,
 3063                                 mod->init_size);
 3064 
 3065         do_mod_ctors(mod);
 3066         /* Start the module */
 3067         if (mod->init != NULL)
 3068                 ret = do_one_initcall(mod->init);
 3069         if (ret < 0) {
 3070                 /* Init routine failed: abort.  Try to protect us from
 3071                    buggy refcounters. */
 3072                 mod->state = MODULE_STATE_GOING;
 3073                 synchronize_sched();
 3074                 module_put(mod);
 3075                 blocking_notifier_call_chain(&module_notify_list,
 3076                                              MODULE_STATE_GOING, mod);
 3077                 free_module(mod);
 3078                 wake_up_all(&module_wq);
 3079                 return ret;
 3080         }
 3081         if (ret > 0) {
 3082                 printk(KERN_WARNING
 3083 "%s: '%s'->init suspiciously returned %d, it should follow 0/-E convention\n"
 3084 "%s: loading module anyway...\n",
 3085                        __func__, mod->name, ret,
 3086                        __func__);
 3087                 dump_stack();
 3088         }
 3089 
 3090         /* Now it's a first class citizen! */
 3091         mod->state = MODULE_STATE_LIVE;
 3092         blocking_notifier_call_chain(&module_notify_list,
 3093                                      MODULE_STATE_LIVE, mod);
 3094 
 3095         /*
 3096          * We need to finish all async code before the module init sequence
 3097          * is done.  This has potential to deadlock.  For example, a newly
 3098          * detected block device can trigger request_module() of the
 3099          * default iosched from async probing task.  Once userland helper
 3100          * reaches here, async_synchronize_full() will wait on the async
 3101          * task waiting on request_module() and deadlock.
 3102          *
 3103          * This deadlock is avoided by perfomring async_synchronize_full()
 3104          * iff module init queued any async jobs.  This isn't a full
 3105          * solution as it will deadlock the same if module loading from
 3106          * async jobs nests more than once; however, due to the various
 3107          * constraints, this hack seems to be the best option for now.
 3108          * Please refer to the following thread for details.
 3109          *
 3110          * http://thread.gmane.org/gmane.linux.kernel/1420814
 3111          */
 3112         if (current->flags & PF_USED_ASYNC)
 3113                 async_synchronize_full();
 3114 
 3115         mutex_lock(&module_mutex);
 3116         /* Drop initial reference. */
 3117         module_put(mod);
 3118         trim_init_extable(mod);
 3119 #ifdef CONFIG_KALLSYMS
 3120         mod->num_symtab = mod->core_num_syms;
 3121         mod->symtab = mod->core_symtab;
 3122         mod->strtab = mod->core_strtab;
 3123 #endif
 3124         unset_module_init_ro_nx(mod);
 3125         module_free(mod, mod->module_init);
 3126         mod->module_init = NULL;
 3127         mod->init_size = 0;
 3128         mod->init_ro_size = 0;
 3129         mod->init_text_size = 0;
 3130         mutex_unlock(&module_mutex);
 3131         wake_up_all(&module_wq);
 3132 
 3133         return 0;
 3134 }
 3135 
 3136 static int may_init_module(void)
 3137 {
 3138         if (!capable(CAP_SYS_MODULE) || modules_disabled)
 3139                 return -EPERM;
 3140 
 3141         return 0;
 3142 }
 3143 
 3144 /* Allocate and load the module: note that size of section 0 is always
 3145    zero, and we rely on this for optional sections. */
 3146 static int load_module(struct load_info *info, const char __user *uargs,
 3147                        int flags)
 3148 {
 3149         struct module *mod, *old;
 3150         long err;
 3151 
 3152         err = module_sig_check(info);
 3153         if (err)
 3154                 goto free_copy;
 3155 
 3156         err = elf_header_check(info);
 3157         if (err)
 3158                 goto free_copy;
 3159 
 3160         /* Figure out module layout, and allocate all the memory. */
 3161         mod = layout_and_allocate(info, flags);
 3162         if (IS_ERR(mod)) {
 3163                 err = PTR_ERR(mod);
 3164                 goto free_copy;
 3165         }
 3166 
 3167         /*
 3168          * We try to place it in the list now to make sure it's unique
 3169          * before we dedicate too many resources.  In particular,
 3170          * temporary percpu memory exhaustion.
 3171          */
 3172         mod->state = MODULE_STATE_UNFORMED;
 3173 again:
 3174         mutex_lock(&module_mutex);
 3175         if ((old = find_module_all(mod->name, true)) != NULL) {
 3176                 if (old->state == MODULE_STATE_COMING
 3177                     || old->state == MODULE_STATE_UNFORMED) {
 3178                         /* Wait in case it fails to load. */
 3179                         mutex_unlock(&module_mutex);
 3180                         err = wait_event_interruptible(module_wq,
 3181                                                finished_loading(mod->name));
 3182                         if (err)
 3183                                 goto free_module;
 3184                         goto again;
 3185                 }
 3186                 err = -EEXIST;
 3187                 mutex_unlock(&module_mutex);
 3188                 goto free_module;
 3189         }
 3190         list_add_rcu(&mod->list, &modules);
 3191         mutex_unlock(&module_mutex);
 3192 
 3193 #ifdef CONFIG_MODULE_SIG
 3194         mod->sig_ok = info->sig_ok;
 3195         if (!mod->sig_ok)
 3196                 add_taint_module(mod, TAINT_FORCED_MODULE);
 3197 #endif
 3198 
 3199         /* Now module is in final location, initialize linked lists, etc. */
 3200         err = module_unload_init(mod);
 3201         if (err)
 3202                 goto unlink_mod;
 3203 
 3204         /* Now we've got everything in the final locations, we can
 3205          * find optional sections. */
 3206         find_module_sections(mod, info);
 3207 
 3208         err = check_module_license_and_versions(mod);
 3209         if (err)
 3210                 goto free_unload;
 3211 
 3212         /* Set up MODINFO_ATTR fields */
 3213         setup_modinfo(mod, info);
 3214 
 3215         /* Fix up syms, so that st_value is a pointer to location. */
 3216         err = simplify_symbols(mod, info);
 3217         if (err < 0)
 3218                 goto free_modinfo;
 3219 
 3220         err = apply_relocations(mod, info);
 3221         if (err < 0)
 3222                 goto free_modinfo;
 3223 
 3224         err = post_relocation(mod, info);
 3225         if (err < 0)
 3226                 goto free_modinfo;
 3227 
 3228         flush_module_icache(mod);
 3229 
 3230         /* Now copy in args */
 3231         mod->args = strndup_user(uargs, ~0UL >> 1);
 3232         if (IS_ERR(mod->args)) {
 3233                 err = PTR_ERR(mod->args);
 3234                 goto free_arch_cleanup;
 3235         }
 3236 
 3237         dynamic_debug_setup(info->debug, info->num_debug);
 3238 
 3239         mutex_lock(&module_mutex);
 3240         /* Find duplicate symbols (must be called under lock). */
 3241         err = verify_export_symbols(mod);
 3242         if (err < 0)
 3243                 goto ddebug_cleanup;
 3244 
 3245         /* This relies on module_mutex for list integrity. */
 3246         module_bug_finalize(info->hdr, info->sechdrs, mod);
 3247 
 3248         /* Mark state as coming so strong_try_module_get() ignores us,
 3249          * but kallsyms etc. can see us. */
 3250         mod->state = MODULE_STATE_COMING;
 3251 
 3252         mutex_unlock(&module_mutex);
 3253 
 3254         /* Module is ready to execute: parsing args may do that. */
 3255         err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
 3256                          -32768, 32767, &ddebug_dyndbg_module_param_cb);
 3257         if (err < 0)
 3258                 goto bug_cleanup;
 3259 
 3260         /* Link in to syfs. */
 3261         err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
 3262         if (err < 0)
 3263                 goto bug_cleanup;
 3264 
 3265         /* Get rid of temporary copy. */
 3266         free_copy(info);
 3267 
 3268         /* Done! */
 3269         trace_module_load(mod);
 3270 
 3271         return do_init_module(mod);
 3272 
 3273  bug_cleanup:
 3274         /* module_bug_cleanup needs module_mutex protection */
 3275         mutex_lock(&module_mutex);
 3276         module_bug_cleanup(mod);
 3277  ddebug_cleanup:
 3278         mutex_unlock(&module_mutex);
 3279         dynamic_debug_remove(info->debug);
 3280         synchronize_sched();
 3281         kfree(mod->args);
 3282  free_arch_cleanup:
 3283         module_arch_cleanup(mod);
 3284  free_modinfo:
 3285         free_modinfo(mod);
 3286  free_unload:
 3287         module_unload_free(mod);
 3288  unlink_mod:
 3289         mutex_lock(&module_mutex);
 3290         /* Unlink carefully: kallsyms could be walking list. */
 3291         list_del_rcu(&mod->list);
 3292         wake_up_all(&module_wq);
 3293         mutex_unlock(&module_mutex);
 3294  free_module:
 3295         module_deallocate(mod, info);
 3296  free_copy:
 3297         free_copy(info);
 3298         return err;
 3299 }
 3300 
 3301 SYSCALL_DEFINE3(init_module, void __user *, umod,
 3302                 unsigned long, len, const char __user *, uargs)
 3303 {
 3304         int err;
 3305         struct load_info info = { };
 3306 
 3307         err = may_init_module();
 3308         if (err)
 3309                 return err;
 3310 
 3311         pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
 3312                umod, len, uargs);
 3313 
 3314         err = copy_module_from_user(umod, len, &info);
 3315         if (err)
 3316                 return err;
 3317 
 3318         return load_module(&info, uargs, 0);
 3319 }
 3320 
 3321 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 3322 {
 3323         int err;
 3324         struct load_info info = { };
 3325 
 3326         err = may_init_module();
 3327         if (err)
 3328                 return err;
 3329 
 3330         pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
 3331 
 3332         if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
 3333                       |MODULE_INIT_IGNORE_VERMAGIC))
 3334                 return -EINVAL;
 3335 
 3336         err = copy_module_from_fd(fd, &info);
 3337         if (err)
 3338                 return err;
 3339 
 3340         return load_module(&info, uargs, flags);
 3341 }
 3342 
 3343 static inline int within(unsigned long addr, void *start, unsigned long size)
 3344 {
 3345         return ((void *)addr >= start && (void *)addr < start + size);
 3346 }
 3347 
 3348 #ifdef CONFIG_KALLSYMS
 3349 /*
 3350  * This ignores the intensely annoying "mapping symbols" found
 3351  * in ARM ELF files: $a, $t and $d.
 3352  */
 3353 static inline int is_arm_mapping_symbol(const char *str)
 3354 {
 3355         return str[0] == '$' && strchr("atd", str[1])
 3356                && (str[2] == '\0' || str[2] == '.');
 3357 }
 3358 
 3359 static const char *get_ksymbol(struct module *mod,
 3360                                unsigned long addr,
 3361                                unsigned long *size,
 3362                                unsigned long *offset)
 3363 {
 3364         unsigned int i, best = 0;
 3365         unsigned long nextval;
 3366 
 3367         /* At worse, next value is at end of module */
 3368         if (within_module_init(addr, mod))
 3369                 nextval = (unsigned long)mod->module_init+mod->init_text_size;
 3370         else
 3371                 nextval = (unsigned long)mod->module_core+mod->core_text_size;
 3372 
 3373         /* Scan for closest preceding symbol, and next symbol. (ELF
 3374            starts real symbols at 1). */
 3375         for (i = 1; i < mod->num_symtab; i++) {
 3376                 if (mod->symtab[i].st_shndx == SHN_UNDEF)
 3377                         continue;
 3378 
 3379                 /* We ignore unnamed symbols: they're uninformative
 3380                  * and inserted at a whim. */
 3381                 if (mod->symtab[i].st_value <= addr
 3382                     && mod->symtab[i].st_value > mod->symtab[best].st_value
 3383                     && *(mod->strtab + mod->symtab[i].st_name) != '\0'
 3384                     && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
 3385                         best = i;
 3386                 if (mod->symtab[i].st_value > addr
 3387                     && mod->symtab[i].st_value < nextval
 3388                     && *(mod->strtab + mod->symtab[i].st_name) != '\0'
 3389                     && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
 3390                         nextval = mod->symtab[i].st_value;
 3391         }
 3392 
 3393         if (!best)
 3394                 return NULL;
 3395 
 3396         if (size)
 3397                 *size = nextval - mod->symtab[best].st_value;
 3398         if (offset)
 3399                 *offset = addr - mod->symtab[best].st_value;
 3400         return mod->strtab + mod->symtab[best].st_name;
 3401 }
 3402 
 3403 /* For kallsyms to ask for address resolution.  NULL means not found.  Careful
 3404  * not to lock to avoid deadlock on oopses, simply disable preemption. */
 3405 const char *module_address_lookup(unsigned long addr,
 3406                             unsigned long *size,
 3407                             unsigned long *offset,
 3408                             char **modname,
 3409                             char *namebuf)
 3410 {
 3411         struct module *mod;
 3412         const char *ret = NULL;
 3413 
 3414         preempt_disable();
 3415         list_for_each_entry_rcu(mod, &modules, list) {
 3416                 if (mod->state == MODULE_STATE_UNFORMED)
 3417                         continue;
 3418                 if (within_module_init(addr, mod) ||
 3419                     within_module_core(addr, mod)) {
 3420                         if (modname)
 3421                                 *modname = mod->name;
 3422                         ret = get_ksymbol(mod, addr, size, offset);
 3423                         break;
 3424                 }
 3425         }
 3426         /* Make a copy in here where it's safe */
 3427         if (ret) {
 3428                 strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
 3429                 ret = namebuf;
 3430         }
 3431         preempt_enable();
 3432         return ret;
 3433 }
 3434 
 3435 int lookup_module_symbol_name(unsigned long addr, char *symname)
 3436 {
 3437         struct module *mod;
 3438 
 3439         preempt_disable();
 3440         list_for_each_entry_rcu(mod, &modules, list) {
 3441                 if (mod->state == MODULE_STATE_UNFORMED)
 3442                         continue;
 3443                 if (within_module_init(addr, mod) ||
 3444                     within_module_core(addr, mod)) {
 3445                         const char *sym;
 3446 
 3447                         sym = get_ksymbol(mod, addr, NULL, NULL);
 3448                         if (!sym)
 3449                                 goto out;
 3450                         strlcpy(symname, sym, KSYM_NAME_LEN);
 3451                         preempt_enable();
 3452                         return 0;
 3453                 }
 3454         }
 3455 out:
 3456         preempt_enable();
 3457         return -ERANGE;
 3458 }
 3459 
 3460 int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
 3461                         unsigned long *offset, char *modname, char *name)
 3462 {
 3463         struct module *mod;
 3464 
 3465         preempt_disable();
 3466         list_for_each_entry_rcu(mod, &modules, list) {
 3467                 if (mod->state == MODULE_STATE_UNFORMED)
 3468                         continue;
 3469                 if (within_module_init(addr, mod) ||
 3470                     within_module_core(addr, mod)) {
 3471                         const char *sym;
 3472 
 3473                         sym = get_ksymbol(mod, addr, size, offset);
 3474                         if (!sym)
 3475                                 goto out;
 3476                         if (modname)
 3477                                 strlcpy(modname, mod->name, MODULE_NAME_LEN);
 3478                         if (name)
 3479                                 strlcpy(name, sym, KSYM_NAME_LEN);
 3480                         preempt_enable();
 3481                         return 0;
 3482                 }
 3483         }
 3484 out:
 3485         preempt_enable();
 3486         return -ERANGE;
 3487 }
 3488 
 3489 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 3490                         char *name, char *module_name, int *exported)
 3491 {
 3492         struct module *mod;
 3493 
 3494         preempt_disable();
 3495         list_for_each_entry_rcu(mod, &modules, list) {
 3496                 if (mod->state == MODULE_STATE_UNFORMED)
 3497                         continue;
 3498                 if (symnum < mod->num_symtab) {
 3499                         *value = mod->symtab[symnum].st_value;
 3500                         *type = mod->symtab[symnum].st_info;
 3501                         strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
 3502                                 KSYM_NAME_LEN);
 3503                         strlcpy(module_name, mod->name, MODULE_NAME_LEN);
 3504                         *exported = is_exported(name, *value, mod);
 3505                         preempt_enable();
 3506                         return 0;
 3507                 }
 3508                 symnum -= mod->num_symtab;
 3509         }
 3510         preempt_enable();
 3511         return -ERANGE;
 3512 }
 3513 
 3514 static unsigned long mod_find_symname(struct module *mod, const char *name)
 3515 {
 3516         unsigned int i;
 3517 
 3518         for (i = 0; i < mod->num_symtab; i++)
 3519                 if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
 3520                     mod->symtab[i].st_info != 'U')
 3521                         return mod->symtab[i].st_value;
 3522         return 0;
 3523 }
 3524 
 3525 /* Look for this name: can be of form module:name. */
 3526 unsigned long module_kallsyms_lookup_name(const char *name)
 3527 {
 3528         struct module *mod;
 3529         char *colon;
 3530         unsigned long ret = 0;
 3531 
 3532         /* Don't lock: we're in enough trouble already. */
 3533         preempt_disable();
 3534         if ((colon = strchr(name, ':')) != NULL) {
 3535                 *colon = '\0';
 3536                 if ((mod = find_module(name)) != NULL)
 3537                         ret = mod_find_symname(mod, colon+1);
 3538                 *colon = ':';
 3539         } else {
 3540                 list_for_each_entry_rcu(mod, &modules, list) {
 3541                         if (mod->state == MODULE_STATE_UNFORMED)
 3542                                 continue;
 3543                         if ((ret = mod_find_symname(mod, name)) != 0)
 3544                                 break;
 3545                 }
 3546         }
 3547         preempt_enable();
 3548         return ret;
 3549 }
 3550 
 3551 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 3552                                              struct module *, unsigned long),
 3553                                    void *data)
 3554 {
 3555         struct module *mod;
 3556         unsigned int i;
 3557         int ret;
 3558 
 3559         list_for_each_entry(mod, &modules, list) {
 3560                 if (mod->state == MODULE_STATE_UNFORMED)
 3561                         continue;
 3562                 for (i = 0; i < mod->num_symtab; i++) {
 3563                         ret = fn(data, mod->strtab + mod->symtab[i].st_name,
 3564                                  mod, mod->symtab[i].st_value);
 3565                         if (ret != 0)
 3566                                 return ret;
 3567                 }
 3568         }
 3569         return 0;
 3570 }
 3571 #endif /* CONFIG_KALLSYMS */
 3572 
 3573 static char *module_flags(struct module *mod, char *buf)
 3574 {
 3575         int bx = 0;
 3576 
 3577         BUG_ON(mod->state == MODULE_STATE_UNFORMED);
 3578         if (mod->taints ||
 3579             mod->state == MODULE_STATE_GOING ||
 3580             mod->state == MODULE_STATE_COMING) {
 3581                 buf[bx++] = '(';
 3582                 bx += module_flags_taint(mod, buf + bx);
 3583                 /* Show a - for module-is-being-unloaded */
 3584                 if (mod->state == MODULE_STATE_GOING)
 3585                         buf[bx++] = '-';
 3586                 /* Show a + for module-is-being-loaded */
 3587                 if (mod->state == MODULE_STATE_COMING)
 3588                         buf[bx++] = '+';
 3589                 buf[bx++] = ')';
 3590         }
 3591         buf[bx] = '\0';
 3592 
 3593         return buf;
 3594 }
 3595 
 3596 #ifdef CONFIG_PROC_FS
 3597 /* Called by the /proc file system to return a list of modules. */
 3598 static void *m_start(struct seq_file *m, loff_t *pos)
 3599 {
 3600         mutex_lock(&module_mutex);
 3601         return seq_list_start(&modules, *pos);
 3602 }
 3603 
 3604 static void *m_next(struct seq_file *m, void *p, loff_t *pos)
 3605 {
 3606         return seq_list_next(p, &modules, pos);
 3607 }
 3608 
 3609 static void m_stop(struct seq_file *m, void *p)
 3610 {
 3611         mutex_unlock(&module_mutex);
 3612 }
 3613 
 3614 static int m_show(struct seq_file *m, void *p)
 3615 {
 3616         struct module *mod = list_entry(p, struct module, list);
 3617         char buf[8];
 3618 
 3619         /* We always ignore unformed modules. */
 3620         if (mod->state == MODULE_STATE_UNFORMED)
 3621                 return 0;
 3622 
 3623         seq_printf(m, "%s %u",
 3624                    mod->name, mod->init_size + mod->core_size);
 3625         print_unload_info(m, mod);
 3626 
 3627         /* Informative for users. */
 3628         seq_printf(m, " %s",
 3629                    mod->state == MODULE_STATE_GOING ? "Unloading":
 3630                    mod->state == MODULE_STATE_COMING ? "Loading":
 3631                    "Live");
 3632         /* Used by oprofile and other similar tools. */
 3633         seq_printf(m, " 0x%pK", mod->module_core);
 3634 
 3635         /* Taints info */
 3636         if (mod->taints)
 3637                 seq_printf(m, " %s", module_flags(mod, buf));
 3638 
 3639         seq_printf(m, "\n");
 3640         return 0;
 3641 }
 3642 
 3643 /* Format: modulename size refcount deps address
 3644 
 3645    Where refcount is a number or -, and deps is a comma-separated list
 3646    of depends or -.
 3647 */
 3648 static const struct seq_operations modules_op = {
 3649         .start  = m_start,
 3650         .next   = m_next,
 3651         .stop   = m_stop,
 3652         .show   = m_show
 3653 };
 3654 
 3655 static int modules_open(struct inode *inode, struct file *file)
 3656 {
 3657         return seq_open(file, &modules_op);
 3658 }
 3659 
 3660 static const struct file_operations proc_modules_operations = {
 3661         .open           = modules_open,
 3662         .read           = seq_read,
 3663         .llseek         = seq_lseek,
 3664         .release        = seq_release,
 3665 };
 3666 
 3667 static int __init proc_modules_init(void)
 3668 {
 3669         proc_create("modules", 0, NULL, &proc_modules_operations);
 3670         return 0;
 3671 }
 3672 module_init(proc_modules_init);
 3673 #endif
 3674 
 3675 /* Given an address, look for it in the module exception tables. */
 3676 const struct exception_table_entry *search_module_extables(unsigned long addr)
 3677 {
 3678         const struct exception_table_entry *e = NULL;
 3679         struct module *mod;
 3680 
 3681         preempt_disable();
 3682         list_for_each_entry_rcu(mod, &modules, list) {
 3683                 if (mod->state == MODULE_STATE_UNFORMED)
 3684                         continue;
 3685                 if (mod->num_exentries == 0)
 3686                         continue;
 3687 
 3688                 e = search_extable(mod->extable,
 3689                                    mod->extable + mod->num_exentries - 1,
 3690                                    addr);
 3691                 if (e)
 3692                         break;
 3693         }
 3694         preempt_enable();
 3695 
 3696         /* Now, if we found one, we are running inside it now, hence
 3697            we cannot unload the module, hence no refcnt needed. */
 3698         return e;
 3699 }
 3700 
 3701 /*
 3702  * is_module_address - is this address inside a module?
 3703  * @addr: the address to check.
 3704  *
 3705  * See is_module_text_address() if you simply want to see if the address
 3706  * is code (not data).
 3707  */
 3708 bool is_module_address(unsigned long addr)
 3709 {
 3710         bool ret;
 3711 
 3712         preempt_disable();
 3713         ret = __module_address(addr) != NULL;
 3714         preempt_enable();
 3715 
 3716         return ret;
 3717 }
 3718 
 3719 /*
 3720  * __module_address - get the module which contains an address.
 3721  * @addr: the address.
 3722  *
 3723  * Must be called with preempt disabled or module mutex held so that
 3724  * module doesn't get freed during this.
 3725  */
 3726 struct module *__module_address(unsigned long addr)
 3727 {
 3728         struct module *mod;
 3729 
 3730         if (addr < module_addr_min || addr > module_addr_max)
 3731                 return NULL;
 3732 
 3733         list_for_each_entry_rcu(mod, &modules, list) {
 3734                 if (mod->state == MODULE_STATE_UNFORMED)
 3735                         continue;
 3736                 if (within_module_core(addr, mod)
 3737                     || within_module_init(addr, mod))
 3738                         return mod;
 3739         }
 3740         return NULL;
 3741 }
 3742 EXPORT_SYMBOL_GPL(__module_address);
 3743 
 3744 /*
 3745  * is_module_text_address - is this address inside module code?
 3746  * @addr: the address to check.
 3747  *
 3748  * See is_module_address() if you simply want to see if the address is
 3749  * anywhere in a module.  See kernel_text_address() for testing if an
 3750  * address corresponds to kernel or module code.
 3751  */
 3752 bool is_module_text_address(unsigned long addr)
 3753 {
 3754         bool ret;
 3755 
 3756         preempt_disable();
 3757         ret = __module_text_address(addr) != NULL;
 3758         preempt_enable();
 3759 
 3760         return ret;
 3761 }
 3762 
 3763 /*
 3764  * __module_text_address - get the module whose code contains an address.
 3765  * @addr: the address.
 3766  *
 3767  * Must be called with preempt disabled or module mutex held so that
 3768  * module doesn't get freed during this.
 3769  */
 3770 struct module *__module_text_address(unsigned long addr)
 3771 {
 3772         struct module *mod = __module_address(addr);
 3773         if (mod) {
 3774                 /* Make sure it's within the text section. */
 3775                 if (!within(addr, mod->module_init, mod->init_text_size)
 3776                     && !within(addr, mod->module_core, mod->core_text_size))
 3777                         mod = NULL;
 3778         }
 3779         return mod;
 3780 }
 3781 EXPORT_SYMBOL_GPL(__module_text_address);
 3782 
 3783 /* Don't grab lock, we're oopsing. */
 3784 void print_modules(void)
 3785 {
 3786         struct module *mod;
 3787         char buf[8];
 3788 
 3789         printk(KERN_DEFAULT "Modules linked in:");
 3790         /* Most callers should already have preempt disabled, but make sure */
 3791         preempt_disable();
 3792         list_for_each_entry_rcu(mod, &modules, list) {
 3793                 if (mod->state == MODULE_STATE_UNFORMED)
 3794                         continue;
 3795                 printk(" %s%s", mod->name, module_flags(mod, buf));
 3796         }
 3797         preempt_enable();
 3798         if (last_unloaded_module[0])
 3799                 printk(" [last unloaded: %s]", last_unloaded_module);
 3800         printk("\n");
 3801 }
 3802 
 3803 #ifdef CONFIG_MODVERSIONS
 3804 /* Generate the signature for all relevant module structures here.
 3805  * If these change, we don't want to try to parse the module. */
 3806 void module_layout(struct module *mod,
 3807                    struct modversion_info *ver,
 3808                    struct kernel_param *kp,
 3809                    struct kernel_symbol *ks,
 3810                    struct tracepoint * const *tp)
 3811 {
 3812 }
 3813 EXPORT_SYMBOL(module_layout);
 3814 #endif

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