1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1994-1996 Søren Schmidt
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/exec.h>
35 #include <sys/fcntl.h>
36 #include <sys/imgact.h>
37 #include <sys/imgact_aout.h>
38 #include <sys/imgact_elf.h>
39 #include <sys/kernel.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/module.h>
43 #include <sys/mutex.h>
44 #include <sys/proc.h>
45 #include <sys/signalvar.h>
46 #include <sys/syscallsubr.h>
47 #include <sys/sysctl.h>
48 #include <sys/sysent.h>
49 #include <sys/sysproto.h>
50 #include <sys/vnode.h>
51
52 #include <vm/vm.h>
53 #include <vm/pmap.h>
54 #include <vm/vm_extern.h>
55 #include <vm/vm_map.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_page.h>
58 #include <vm/vm_param.h>
59
60 #include <machine/cpu.h>
61 #include <machine/cputypes.h>
62 #include <machine/md_var.h>
63 #include <machine/pcb.h>
64 #include <machine/trap.h>
65
66 #include <i386/linux/linux.h>
67 #include <i386/linux/linux_proto.h>
68 #include <compat/linux/linux_emul.h>
69 #include <compat/linux/linux_ioctl.h>
70 #include <compat/linux/linux_mib.h>
71 #include <compat/linux/linux_misc.h>
72 #include <compat/linux/linux_signal.h>
73 #include <compat/linux/linux_util.h>
74 #include <compat/linux/linux_vdso.h>
75
76 MODULE_VERSION(linux, 1);
77
78 #define LINUX_PS_STRINGS (LINUX_USRSTACK - sizeof(struct ps_strings))
79
80 static int linux_szsigcode;
81 static vm_object_t linux_shared_page_obj;
82 static char *linux_shared_page_mapping;
83 extern char _binary_linux_locore_o_start;
84 extern char _binary_linux_locore_o_end;
85
86 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
87
88 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
89
90 static int linux_fixup(uintptr_t *stack_base,
91 struct image_params *iparams);
92 static int linux_fixup_elf(uintptr_t *stack_base,
93 struct image_params *iparams);
94 static void linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
95 static void linux_exec_setregs(struct thread *td,
96 struct image_params *imgp, uintptr_t stack);
97 static int linux_copyout_strings(struct image_params *imgp,
98 uintptr_t *stack_base);
99 static bool linux_trans_osrel(const Elf_Note *note, int32_t *osrel);
100 static void linux_vdso_install(void *param);
101 static void linux_vdso_deinstall(void *param);
102
103 static int linux_szplatform;
104 const char *linux_kplatform;
105
106 #define LINUX_T_UNKNOWN 255
107 static int _bsd_to_linux_trapcode[] = {
108 LINUX_T_UNKNOWN, /* 0 */
109 6, /* 1 T_PRIVINFLT */
110 LINUX_T_UNKNOWN, /* 2 */
111 3, /* 3 T_BPTFLT */
112 LINUX_T_UNKNOWN, /* 4 */
113 LINUX_T_UNKNOWN, /* 5 */
114 16, /* 6 T_ARITHTRAP */
115 254, /* 7 T_ASTFLT */
116 LINUX_T_UNKNOWN, /* 8 */
117 13, /* 9 T_PROTFLT */
118 1, /* 10 T_TRCTRAP */
119 LINUX_T_UNKNOWN, /* 11 */
120 14, /* 12 T_PAGEFLT */
121 LINUX_T_UNKNOWN, /* 13 */
122 17, /* 14 T_ALIGNFLT */
123 LINUX_T_UNKNOWN, /* 15 */
124 LINUX_T_UNKNOWN, /* 16 */
125 LINUX_T_UNKNOWN, /* 17 */
126 0, /* 18 T_DIVIDE */
127 2, /* 19 T_NMI */
128 4, /* 20 T_OFLOW */
129 5, /* 21 T_BOUND */
130 7, /* 22 T_DNA */
131 8, /* 23 T_DOUBLEFLT */
132 9, /* 24 T_FPOPFLT */
133 10, /* 25 T_TSSFLT */
134 11, /* 26 T_SEGNPFLT */
135 12, /* 27 T_STKFLT */
136 18, /* 28 T_MCHK */
137 19, /* 29 T_XMMFLT */
138 15 /* 30 T_RESERVED */
139 };
140 #define bsd_to_linux_trapcode(code) \
141 ((code)<nitems(_bsd_to_linux_trapcode)? \
142 _bsd_to_linux_trapcode[(code)]: \
143 LINUX_T_UNKNOWN)
144
145 LINUX_VDSO_SYM_INTPTR(linux_sigcode);
146 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode);
147 LINUX_VDSO_SYM_INTPTR(linux_vsyscall);
148
149 /*
150 * If FreeBSD & Linux have a difference of opinion about what a trap
151 * means, deal with it here.
152 *
153 * MPSAFE
154 */
155 static int
156 linux_translate_traps(int signal, int trap_code)
157 {
158 if (signal != SIGBUS)
159 return (signal);
160 switch (trap_code) {
161 case T_PROTFLT:
162 case T_TSSFLT:
163 case T_DOUBLEFLT:
164 case T_PAGEFLT:
165 return (SIGSEGV);
166 default:
167 return (signal);
168 }
169 }
170
171 static int
172 linux_fixup(uintptr_t *stack_base, struct image_params *imgp)
173 {
174 register_t *base, *argv, *envp;
175
176 base = (register_t *)*stack_base;
177 argv = base;
178 envp = base + (imgp->args->argc + 1);
179 base--;
180 suword(base, (intptr_t)envp);
181 base--;
182 suword(base, (intptr_t)argv);
183 base--;
184 suword(base, imgp->args->argc);
185 *stack_base = (uintptr_t)base;
186 return (0);
187 }
188
189 static int
190 linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
191 {
192 struct proc *p;
193 Elf32_Auxargs *args;
194 Elf32_Auxinfo *argarray, *pos;
195 Elf32_Addr *uplatform;
196 struct ps_strings *arginfo;
197 int error, issetugid;
198
199 p = imgp->proc;
200 issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0;
201 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
202 uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform);
203 args = (Elf32_Auxargs *)imgp->auxargs;
204 argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
205 M_WAITOK | M_ZERO);
206
207 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR,
208 imgp->proc->p_sysent->sv_shared_page_base);
209 AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO, linux_vsyscall);
210 AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature);
211
212 /*
213 * Do not export AT_CLKTCK when emulating Linux kernel prior to 2.4.0,
214 * as it has appeared in the 2.4.0-rc7 first time.
215 * Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK),
216 * glibc falls back to the hard-coded CLK_TCK value when aux entry
217 * is not present.
218 * Also see linux_times() implementation.
219 */
220 if (linux_kernver(curthread) >= LINUX_KERNVER_2004000)
221 AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
222 AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
223 AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
224 AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
225 AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
226 AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
227 AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
228 AUXARGS_ENTRY(pos, AT_BASE, args->base);
229 AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
230 AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
231 AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
232 AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
233 AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
234 AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(uplatform));
235 AUXARGS_ENTRY_PTR(pos, LINUX_AT_RANDOM, imgp->canary);
236 if (imgp->execpathp != 0)
237 AUXARGS_ENTRY_PTR(pos, LINUX_AT_EXECFN, imgp->execpathp);
238 if (args->execfd != -1)
239 AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
240 AUXARGS_ENTRY(pos, AT_NULL, 0);
241
242 free(imgp->auxargs, M_TEMP);
243 imgp->auxargs = NULL;
244 KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
245
246 error = copyout(argarray, (void *)base,
247 sizeof(*argarray) * LINUX_AT_COUNT);
248 free(argarray, M_TEMP);
249 return (error);
250 }
251
252 static int
253 linux_fixup_elf(uintptr_t *stack_base, struct image_params *imgp)
254 {
255 register_t *base;
256
257 base = (register_t *)*stack_base;
258 base--;
259 if (suword(base, (register_t)imgp->args->argc) == -1)
260 return (EFAULT);
261 *stack_base = (uintptr_t)base;
262 return (0);
263 }
264
265 /*
266 * Copied from kern/kern_exec.c
267 */
268 static int
269 linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
270 {
271 int argc, envc, error;
272 char **vectp;
273 char *stringp;
274 uintptr_t destp, ustringp;
275 struct ps_strings *arginfo;
276 char canary[LINUX_AT_RANDOM_LEN];
277 size_t execpath_len;
278 struct proc *p;
279
280 /* Calculate string base and vector table pointers. */
281 p = imgp->proc;
282 if (imgp->execpath != NULL && imgp->auxargs != NULL)
283 execpath_len = strlen(imgp->execpath) + 1;
284 else
285 execpath_len = 0;
286 arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
287 destp = (uintptr_t)arginfo;
288
289 /* Install LINUX_PLATFORM. */
290 destp -= linux_szplatform;
291 destp = rounddown2(destp, sizeof(void *));
292 error = copyout(linux_kplatform, (void *)destp, linux_szplatform);
293 if (error != 0)
294 return (error);
295
296 if (execpath_len != 0) {
297 destp -= execpath_len;
298 destp = rounddown2(destp, sizeof(void *));
299 imgp->execpathp = (void *)destp;
300 error = copyout(imgp->execpath, imgp->execpathp, execpath_len);
301 if (error != 0)
302 return (error);
303 }
304
305 /* Prepare the canary for SSP. */
306 arc4rand(canary, sizeof(canary), 0);
307 destp -= roundup(sizeof(canary), sizeof(void *));
308 imgp->canary = (void *)destp;
309 error = copyout(canary, imgp->canary, sizeof(canary));
310 if (error != 0)
311 return (error);
312
313 /* Allocate room for the argument and environment strings. */
314 destp -= ARG_MAX - imgp->args->stringspace;
315 destp = rounddown2(destp, sizeof(void *));
316 ustringp = destp;
317
318 if (imgp->auxargs) {
319 /*
320 * Allocate room on the stack for the ELF auxargs
321 * array. It has LINUX_AT_COUNT entries.
322 */
323 destp -= LINUX_AT_COUNT * sizeof(Elf32_Auxinfo);
324 destp = rounddown2(destp, sizeof(void *));
325 }
326
327 vectp = (char **)destp;
328
329 /*
330 * Allocate room for the argv[] and env vectors including the
331 * terminating NULL pointers.
332 */
333 vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
334
335 /* vectp also becomes our initial stack base. */
336 *stack_base = (uintptr_t)vectp;
337
338 stringp = imgp->args->begin_argv;
339 argc = imgp->args->argc;
340 envc = imgp->args->envc;
341
342 /* Copy out strings - arguments and environment. */
343 error = copyout(stringp, (void *)ustringp,
344 ARG_MAX - imgp->args->stringspace);
345 if (error != 0)
346 return (error);
347
348 /* Fill in "ps_strings" struct for ps, w, etc. */
349 if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
350 suword(&arginfo->ps_nargvstr, argc) != 0)
351 return (EFAULT);
352
353 /* Fill in argument portion of vector table. */
354 for (; argc > 0; --argc) {
355 if (suword(vectp++, ustringp) != 0)
356 return (EFAULT);
357 while (*stringp++ != 0)
358 ustringp++;
359 ustringp++;
360 }
361
362 /* A null vector table pointer separates the argp's from the envp's. */
363 if (suword(vectp++, 0) != 0)
364 return (EFAULT);
365
366 if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
367 suword(&arginfo->ps_nenvstr, envc) != 0)
368 return (EFAULT);
369
370 /* Fill in environment portion of vector table. */
371 for (; envc > 0; --envc) {
372 if (suword(vectp++, ustringp) != 0)
373 return (EFAULT);
374 while (*stringp++ != 0)
375 ustringp++;
376 ustringp++;
377 }
378
379 /* The end of the vector table is a null pointer. */
380 if (suword(vectp, 0) != 0)
381 return (EFAULT);
382
383 if (imgp->auxargs) {
384 vectp++;
385 error = imgp->sysent->sv_copyout_auxargs(imgp,
386 (uintptr_t)vectp);
387 if (error != 0)
388 return (error);
389 }
390
391 return (0);
392 }
393
394 static void
395 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
396 {
397 struct thread *td = curthread;
398 struct proc *p = td->td_proc;
399 struct sigacts *psp;
400 struct trapframe *regs;
401 struct l_rt_sigframe *fp, frame;
402 int sig, code;
403 int oonstack;
404
405 sig = ksi->ksi_signo;
406 code = ksi->ksi_code;
407 PROC_LOCK_ASSERT(p, MA_OWNED);
408 psp = p->p_sigacts;
409 mtx_assert(&psp->ps_mtx, MA_OWNED);
410 regs = td->td_frame;
411 oonstack = sigonstack(regs->tf_esp);
412
413 /* Allocate space for the signal handler context. */
414 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
415 SIGISMEMBER(psp->ps_sigonstack, sig)) {
416 fp = (struct l_rt_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
417 td->td_sigstk.ss_size - sizeof(struct l_rt_sigframe));
418 } else
419 fp = (struct l_rt_sigframe *)regs->tf_esp - 1;
420 mtx_unlock(&psp->ps_mtx);
421
422 /* Build the argument list for the signal handler. */
423 sig = bsd_to_linux_signal(sig);
424
425 bzero(&frame, sizeof(frame));
426
427 frame.sf_handler = catcher;
428 frame.sf_sig = sig;
429 frame.sf_siginfo = &fp->sf_si;
430 frame.sf_ucontext = &fp->sf_sc;
431
432 /* Fill in POSIX parts. */
433 ksiginfo_to_lsiginfo(ksi, &frame.sf_si, sig);
434
435 /* Build the signal context to be used by sigreturn. */
436 frame.sf_sc.uc_flags = 0; /* XXX ??? */
437 frame.sf_sc.uc_link = NULL; /* XXX ??? */
438
439 frame.sf_sc.uc_stack.ss_sp = td->td_sigstk.ss_sp;
440 frame.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size;
441 frame.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
442 ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
443 PROC_UNLOCK(p);
444
445 bsd_to_linux_sigset(mask, &frame.sf_sc.uc_sigmask);
446
447 frame.sf_sc.uc_mcontext.sc_mask = frame.sf_sc.uc_sigmask.__mask;
448 frame.sf_sc.uc_mcontext.sc_gs = rgs();
449 frame.sf_sc.uc_mcontext.sc_fs = regs->tf_fs;
450 frame.sf_sc.uc_mcontext.sc_es = regs->tf_es;
451 frame.sf_sc.uc_mcontext.sc_ds = regs->tf_ds;
452 frame.sf_sc.uc_mcontext.sc_edi = regs->tf_edi;
453 frame.sf_sc.uc_mcontext.sc_esi = regs->tf_esi;
454 frame.sf_sc.uc_mcontext.sc_ebp = regs->tf_ebp;
455 frame.sf_sc.uc_mcontext.sc_ebx = regs->tf_ebx;
456 frame.sf_sc.uc_mcontext.sc_esp = regs->tf_esp;
457 frame.sf_sc.uc_mcontext.sc_edx = regs->tf_edx;
458 frame.sf_sc.uc_mcontext.sc_ecx = regs->tf_ecx;
459 frame.sf_sc.uc_mcontext.sc_eax = regs->tf_eax;
460 frame.sf_sc.uc_mcontext.sc_eip = regs->tf_eip;
461 frame.sf_sc.uc_mcontext.sc_cs = regs->tf_cs;
462 frame.sf_sc.uc_mcontext.sc_eflags = regs->tf_eflags;
463 frame.sf_sc.uc_mcontext.sc_esp_at_signal = regs->tf_esp;
464 frame.sf_sc.uc_mcontext.sc_ss = regs->tf_ss;
465 frame.sf_sc.uc_mcontext.sc_err = regs->tf_err;
466 frame.sf_sc.uc_mcontext.sc_cr2 = (register_t)ksi->ksi_addr;
467 frame.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
468
469 if (copyout(&frame, fp, sizeof(frame)) != 0) {
470 /*
471 * Process has trashed its stack; give it an illegal
472 * instruction to halt it in its tracks.
473 */
474 PROC_LOCK(p);
475 sigexit(td, SIGILL);
476 }
477
478 /* Build context to run handler in. */
479 regs->tf_esp = (int)fp;
480 regs->tf_eip = linux_rt_sigcode;
481 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
482 regs->tf_cs = _ucodesel;
483 regs->tf_ds = _udatasel;
484 regs->tf_es = _udatasel;
485 regs->tf_fs = _udatasel;
486 regs->tf_ss = _udatasel;
487 PROC_LOCK(p);
488 mtx_lock(&psp->ps_mtx);
489 }
490
491 /*
492 * Send an interrupt to process.
493 *
494 * Stack is set up to allow sigcode stored
495 * in u. to call routine, followed by kcall
496 * to sigreturn routine below. After sigreturn
497 * resets the signal mask, the stack, and the
498 * frame pointer, it returns to the user
499 * specified pc, psl.
500 */
501 static void
502 linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
503 {
504 struct thread *td = curthread;
505 struct proc *p = td->td_proc;
506 struct sigacts *psp;
507 struct trapframe *regs;
508 struct l_sigframe *fp, frame;
509 l_sigset_t lmask;
510 int sig, code;
511 int oonstack;
512
513 PROC_LOCK_ASSERT(p, MA_OWNED);
514 psp = p->p_sigacts;
515 sig = ksi->ksi_signo;
516 code = ksi->ksi_code;
517 mtx_assert(&psp->ps_mtx, MA_OWNED);
518 if (SIGISMEMBER(psp->ps_siginfo, sig)) {
519 /* Signal handler installed with SA_SIGINFO. */
520 linux_rt_sendsig(catcher, ksi, mask);
521 return;
522 }
523 regs = td->td_frame;
524 oonstack = sigonstack(regs->tf_esp);
525
526 /* Allocate space for the signal handler context. */
527 if ((td->td_pflags & TDP_ALTSTACK) && !oonstack &&
528 SIGISMEMBER(psp->ps_sigonstack, sig)) {
529 fp = (struct l_sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
530 td->td_sigstk.ss_size - sizeof(struct l_sigframe));
531 } else
532 fp = (struct l_sigframe *)regs->tf_esp - 1;
533 mtx_unlock(&psp->ps_mtx);
534 PROC_UNLOCK(p);
535
536 /* Build the argument list for the signal handler. */
537 sig = bsd_to_linux_signal(sig);
538
539 bzero(&frame, sizeof(frame));
540
541 frame.sf_handler = catcher;
542 frame.sf_sig = sig;
543
544 bsd_to_linux_sigset(mask, &lmask);
545
546 /* Build the signal context to be used by sigreturn. */
547 frame.sf_sc.sc_mask = lmask.__mask;
548 frame.sf_sc.sc_gs = rgs();
549 frame.sf_sc.sc_fs = regs->tf_fs;
550 frame.sf_sc.sc_es = regs->tf_es;
551 frame.sf_sc.sc_ds = regs->tf_ds;
552 frame.sf_sc.sc_edi = regs->tf_edi;
553 frame.sf_sc.sc_esi = regs->tf_esi;
554 frame.sf_sc.sc_ebp = regs->tf_ebp;
555 frame.sf_sc.sc_ebx = regs->tf_ebx;
556 frame.sf_sc.sc_esp = regs->tf_esp;
557 frame.sf_sc.sc_edx = regs->tf_edx;
558 frame.sf_sc.sc_ecx = regs->tf_ecx;
559 frame.sf_sc.sc_eax = regs->tf_eax;
560 frame.sf_sc.sc_eip = regs->tf_eip;
561 frame.sf_sc.sc_cs = regs->tf_cs;
562 frame.sf_sc.sc_eflags = regs->tf_eflags;
563 frame.sf_sc.sc_esp_at_signal = regs->tf_esp;
564 frame.sf_sc.sc_ss = regs->tf_ss;
565 frame.sf_sc.sc_err = regs->tf_err;
566 frame.sf_sc.sc_cr2 = (register_t)ksi->ksi_addr;
567 frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(ksi->ksi_trapno);
568
569 frame.sf_extramask[0] = lmask.__mask;
570
571 if (copyout(&frame, fp, sizeof(frame)) != 0) {
572 /*
573 * Process has trashed its stack; give it an illegal
574 * instruction to halt it in its tracks.
575 */
576 PROC_LOCK(p);
577 sigexit(td, SIGILL);
578 }
579
580 /* Build context to run handler in. */
581 regs->tf_esp = (int)fp;
582 regs->tf_eip = linux_sigcode;
583 regs->tf_eflags &= ~(PSL_T | PSL_VM | PSL_D);
584 regs->tf_cs = _ucodesel;
585 regs->tf_ds = _udatasel;
586 regs->tf_es = _udatasel;
587 regs->tf_fs = _udatasel;
588 regs->tf_ss = _udatasel;
589 PROC_LOCK(p);
590 mtx_lock(&psp->ps_mtx);
591 }
592
593 /*
594 * System call to cleanup state after a signal
595 * has been taken. Reset signal mask and
596 * stack state from context left by sendsig (above).
597 * Return to previous pc and psl as specified by
598 * context left by sendsig. Check carefully to
599 * make sure that the user has not modified the
600 * psl to gain improper privileges or to cause
601 * a machine fault.
602 */
603 int
604 linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
605 {
606 struct l_sigframe frame;
607 struct trapframe *regs;
608 l_sigset_t lmask;
609 sigset_t bmask;
610 int eflags;
611 ksiginfo_t ksi;
612
613 regs = td->td_frame;
614
615 /*
616 * The trampoline code hands us the sigframe.
617 * It is unsafe to keep track of it ourselves, in the event that a
618 * program jumps out of a signal handler.
619 */
620 if (copyin(args->sfp, &frame, sizeof(frame)) != 0)
621 return (EFAULT);
622
623 /* Check for security violations. */
624 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
625 eflags = frame.sf_sc.sc_eflags;
626 if (!EFLAGS_SECURE(eflags, regs->tf_eflags))
627 return (EINVAL);
628
629 /*
630 * Don't allow users to load a valid privileged %cs. Let the
631 * hardware check for invalid selectors, excess privilege in
632 * other selectors, invalid %eip's and invalid %esp's.
633 */
634 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL)
635 if (!CS_SECURE(frame.sf_sc.sc_cs)) {
636 ksiginfo_init_trap(&ksi);
637 ksi.ksi_signo = SIGBUS;
638 ksi.ksi_code = BUS_OBJERR;
639 ksi.ksi_trapno = T_PROTFLT;
640 ksi.ksi_addr = (void *)regs->tf_eip;
641 trapsignal(td, &ksi);
642 return (EINVAL);
643 }
644
645 lmask.__mask = frame.sf_sc.sc_mask;
646 linux_to_bsd_sigset(&lmask, &bmask);
647 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
648
649 /* Restore signal context. */
650 /* %gs was restored by the trampoline. */
651 regs->tf_fs = frame.sf_sc.sc_fs;
652 regs->tf_es = frame.sf_sc.sc_es;
653 regs->tf_ds = frame.sf_sc.sc_ds;
654 regs->tf_edi = frame.sf_sc.sc_edi;
655 regs->tf_esi = frame.sf_sc.sc_esi;
656 regs->tf_ebp = frame.sf_sc.sc_ebp;
657 regs->tf_ebx = frame.sf_sc.sc_ebx;
658 regs->tf_edx = frame.sf_sc.sc_edx;
659 regs->tf_ecx = frame.sf_sc.sc_ecx;
660 regs->tf_eax = frame.sf_sc.sc_eax;
661 regs->tf_eip = frame.sf_sc.sc_eip;
662 regs->tf_cs = frame.sf_sc.sc_cs;
663 regs->tf_eflags = eflags;
664 regs->tf_esp = frame.sf_sc.sc_esp_at_signal;
665 regs->tf_ss = frame.sf_sc.sc_ss;
666
667 return (EJUSTRETURN);
668 }
669
670 /*
671 * System call to cleanup state after a signal
672 * has been taken. Reset signal mask and
673 * stack state from context left by rt_sendsig (above).
674 * Return to previous pc and psl as specified by
675 * context left by sendsig. Check carefully to
676 * make sure that the user has not modified the
677 * psl to gain improper privileges or to cause
678 * a machine fault.
679 */
680 int
681 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
682 {
683 struct l_ucontext uc;
684 struct l_sigcontext *context;
685 sigset_t bmask;
686 l_stack_t *lss;
687 stack_t ss;
688 struct trapframe *regs;
689 int eflags;
690 ksiginfo_t ksi;
691
692 regs = td->td_frame;
693
694 /*
695 * The trampoline code hands us the ucontext.
696 * It is unsafe to keep track of it ourselves, in the event that a
697 * program jumps out of a signal handler.
698 */
699 if (copyin(args->ucp, &uc, sizeof(uc)) != 0)
700 return (EFAULT);
701
702 context = &uc.uc_mcontext;
703
704 /* Check for security violations. */
705 #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
706 eflags = context->sc_eflags;
707 if (!EFLAGS_SECURE(eflags, regs->tf_eflags))
708 return (EINVAL);
709
710 /*
711 * Don't allow users to load a valid privileged %cs. Let the
712 * hardware check for invalid selectors, excess privilege in
713 * other selectors, invalid %eip's and invalid %esp's.
714 */
715 #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL)
716 if (!CS_SECURE(context->sc_cs)) {
717 ksiginfo_init_trap(&ksi);
718 ksi.ksi_signo = SIGBUS;
719 ksi.ksi_code = BUS_OBJERR;
720 ksi.ksi_trapno = T_PROTFLT;
721 ksi.ksi_addr = (void *)regs->tf_eip;
722 trapsignal(td, &ksi);
723 return (EINVAL);
724 }
725
726 linux_to_bsd_sigset(&uc.uc_sigmask, &bmask);
727 kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
728
729 /* Restore signal context. */
730 /* %gs was restored by the trampoline. */
731 regs->tf_fs = context->sc_fs;
732 regs->tf_es = context->sc_es;
733 regs->tf_ds = context->sc_ds;
734 regs->tf_edi = context->sc_edi;
735 regs->tf_esi = context->sc_esi;
736 regs->tf_ebp = context->sc_ebp;
737 regs->tf_ebx = context->sc_ebx;
738 regs->tf_edx = context->sc_edx;
739 regs->tf_ecx = context->sc_ecx;
740 regs->tf_eax = context->sc_eax;
741 regs->tf_eip = context->sc_eip;
742 regs->tf_cs = context->sc_cs;
743 regs->tf_eflags = eflags;
744 regs->tf_esp = context->sc_esp_at_signal;
745 regs->tf_ss = context->sc_ss;
746
747 /* Call sigaltstack & ignore results. */
748 lss = &uc.uc_stack;
749 ss.ss_sp = lss->ss_sp;
750 ss.ss_size = lss->ss_size;
751 ss.ss_flags = linux_to_bsd_sigaltstack(lss->ss_flags);
752
753 (void)kern_sigaltstack(td, &ss, NULL);
754
755 return (EJUSTRETURN);
756 }
757
758 static int
759 linux_fetch_syscall_args(struct thread *td)
760 {
761 struct proc *p;
762 struct trapframe *frame;
763 struct syscall_args *sa;
764
765 p = td->td_proc;
766 frame = td->td_frame;
767 sa = &td->td_sa;
768
769 sa->code = frame->tf_eax;
770 sa->args[0] = frame->tf_ebx;
771 sa->args[1] = frame->tf_ecx;
772 sa->args[2] = frame->tf_edx;
773 sa->args[3] = frame->tf_esi;
774 sa->args[4] = frame->tf_edi;
775 sa->args[5] = frame->tf_ebp; /* Unconfirmed */
776
777 if (sa->code >= p->p_sysent->sv_size)
778 /* nosys */
779 sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1];
780 else
781 sa->callp = &p->p_sysent->sv_table[sa->code];
782
783 td->td_retval[0] = 0;
784 td->td_retval[1] = frame->tf_edx;
785
786 return (0);
787 }
788
789 static void
790 linux_set_syscall_retval(struct thread *td, int error)
791 {
792 struct trapframe *frame = td->td_frame;
793
794 cpu_set_syscall_retval(td, error);
795
796 if (__predict_false(error != 0)) {
797 if (error != ERESTART && error != EJUSTRETURN)
798 frame->tf_eax = bsd_to_linux_errno(error);
799 }
800 }
801
802 /*
803 * exec_setregs may initialize some registers differently than Linux
804 * does, thus potentially confusing Linux binaries. If necessary, we
805 * override the exec_setregs default(s) here.
806 */
807 static void
808 linux_exec_setregs(struct thread *td, struct image_params *imgp,
809 uintptr_t stack)
810 {
811 struct pcb *pcb = td->td_pcb;
812
813 exec_setregs(td, imgp, stack);
814
815 /* Linux sets %gs to 0, we default to _udatasel. */
816 pcb->pcb_gs = 0;
817 load_gs(0);
818
819 pcb->pcb_initial_npxcw = __LINUX_NPXCW__;
820 }
821
822 static void
823 linux_get_machine(const char **dst)
824 {
825
826 switch (cpu_class) {
827 case CPUCLASS_686:
828 *dst = "i686";
829 break;
830 case CPUCLASS_586:
831 *dst = "i586";
832 break;
833 case CPUCLASS_486:
834 *dst = "i486";
835 break;
836 default:
837 *dst = "i386";
838 }
839 }
840
841 struct sysentvec linux_sysvec = {
842 .sv_size = LINUX_SYS_MAXSYSCALL,
843 .sv_table = linux_sysent,
844 .sv_transtrap = linux_translate_traps,
845 .sv_fixup = linux_fixup,
846 .sv_sendsig = linux_sendsig,
847 .sv_sigcode = &_binary_linux_locore_o_start,
848 .sv_szsigcode = &linux_szsigcode,
849 .sv_name = "Linux a.out",
850 .sv_coredump = NULL,
851 .sv_imgact_try = linux_exec_imgact_try,
852 .sv_minsigstksz = LINUX_MINSIGSTKSZ,
853 .sv_minuser = VM_MIN_ADDRESS,
854 .sv_maxuser = VM_MAXUSER_ADDRESS,
855 .sv_usrstack = LINUX_USRSTACK,
856 .sv_psstrings = PS_STRINGS,
857 .sv_stackprot = VM_PROT_ALL,
858 .sv_copyout_strings = exec_copyout_strings,
859 .sv_setregs = linux_exec_setregs,
860 .sv_fixlimit = NULL,
861 .sv_maxssiz = NULL,
862 .sv_flags = SV_ABI_LINUX | SV_AOUT | SV_IA32 | SV_ILP32 |
863 SV_SIG_DISCIGN | SV_SIG_WAITNDQ,
864 .sv_set_syscall_retval = linux_set_syscall_retval,
865 .sv_fetch_syscall_args = linux_fetch_syscall_args,
866 .sv_syscallnames = NULL,
867 .sv_shared_page_base = LINUX_SHAREDPAGE,
868 .sv_shared_page_len = PAGE_SIZE,
869 .sv_schedtail = linux_schedtail,
870 .sv_thread_detach = linux_thread_detach,
871 .sv_trap = NULL,
872 .sv_onexec = linux_on_exec,
873 .sv_onexit = linux_on_exit,
874 .sv_ontdexit = linux_thread_dtor,
875 .sv_setid_allowed = &linux_setid_allowed_query,
876 };
877 INIT_SYSENTVEC(aout_sysvec, &linux_sysvec);
878
879 struct sysentvec elf_linux_sysvec = {
880 .sv_size = LINUX_SYS_MAXSYSCALL,
881 .sv_table = linux_sysent,
882 .sv_transtrap = linux_translate_traps,
883 .sv_fixup = linux_fixup_elf,
884 .sv_sendsig = linux_sendsig,
885 .sv_sigcode = &_binary_linux_locore_o_start,
886 .sv_szsigcode = &linux_szsigcode,
887 .sv_name = "Linux ELF32",
888 .sv_coredump = elf32_coredump,
889 .sv_imgact_try = linux_exec_imgact_try,
890 .sv_minsigstksz = LINUX_MINSIGSTKSZ,
891 .sv_minuser = VM_MIN_ADDRESS,
892 .sv_maxuser = VM_MAXUSER_ADDRESS,
893 .sv_usrstack = LINUX_USRSTACK,
894 .sv_psstrings = LINUX_PS_STRINGS,
895 .sv_stackprot = VM_PROT_ALL,
896 .sv_copyout_auxargs = linux_copyout_auxargs,
897 .sv_copyout_strings = linux_copyout_strings,
898 .sv_setregs = linux_exec_setregs,
899 .sv_fixlimit = NULL,
900 .sv_maxssiz = NULL,
901 .sv_flags = SV_ABI_LINUX | SV_IA32 | SV_ILP32 | SV_SHP |
902 SV_SIG_DISCIGN | SV_SIG_WAITNDQ,
903 .sv_set_syscall_retval = linux_set_syscall_retval,
904 .sv_fetch_syscall_args = linux_fetch_syscall_args,
905 .sv_syscallnames = NULL,
906 .sv_shared_page_base = LINUX_SHAREDPAGE,
907 .sv_shared_page_len = PAGE_SIZE,
908 .sv_schedtail = linux_schedtail,
909 .sv_thread_detach = linux_thread_detach,
910 .sv_trap = NULL,
911 .sv_onexec = linux_on_exec,
912 .sv_onexit = linux_on_exit,
913 .sv_ontdexit = linux_thread_dtor,
914 .sv_setid_allowed = &linux_setid_allowed_query,
915 };
916
917 static void
918 linux_vdso_install(void *param)
919 {
920
921 linux_szsigcode = (&_binary_linux_locore_o_end -
922 &_binary_linux_locore_o_start);
923
924 if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len)
925 panic("Linux invalid vdso size\n");
926
927 __elfN(linux_vdso_fixup)(&elf_linux_sysvec);
928
929 linux_shared_page_obj = __elfN(linux_shared_page_init)
930 (&linux_shared_page_mapping);
931
932 __elfN(linux_vdso_reloc)(&elf_linux_sysvec);
933
934 bcopy(elf_linux_sysvec.sv_sigcode, linux_shared_page_mapping,
935 linux_szsigcode);
936 elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj;
937 }
938 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY,
939 linux_vdso_install, NULL);
940
941 static void
942 linux_vdso_deinstall(void *param)
943 {
944
945 __elfN(linux_shared_page_fini)(linux_shared_page_obj,
946 linux_shared_page_mapping);
947 }
948 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
949 linux_vdso_deinstall, NULL);
950
951 static char GNU_ABI_VENDOR[] = "GNU";
952 static int GNULINUX_ABI_DESC = 0;
953
954 static bool
955 linux_trans_osrel(const Elf_Note *note, int32_t *osrel)
956 {
957 const Elf32_Word *desc;
958 uintptr_t p;
959
960 p = (uintptr_t)(note + 1);
961 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
962
963 desc = (const Elf32_Word *)p;
964 if (desc[0] != GNULINUX_ABI_DESC)
965 return (false);
966
967 /*
968 * For Linux we encode osrel using the Linux convention of
969 * (version << 16) | (major << 8) | (minor)
970 * See macro in linux_mib.h
971 */
972 *osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
973
974 return (true);
975 }
976
977 static Elf_Brandnote linux_brandnote = {
978 .hdr.n_namesz = sizeof(GNU_ABI_VENDOR),
979 .hdr.n_descsz = 16, /* XXX at least 16 */
980 .hdr.n_type = 1,
981 .vendor = GNU_ABI_VENDOR,
982 .flags = BN_TRANSLATE_OSREL,
983 .trans_osrel = linux_trans_osrel
984 };
985
986 static Elf32_Brandinfo linux_brand = {
987 .brand = ELFOSABI_LINUX,
988 .machine = EM_386,
989 .compat_3_brand = "Linux",
990 .emul_path = linux_emul_path,
991 .interp_path = "/lib/ld-linux.so.1",
992 .sysvec = &elf_linux_sysvec,
993 .interp_newpath = NULL,
994 .brand_note = &linux_brandnote,
995 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
996 };
997
998 static Elf32_Brandinfo linux_glibc2brand = {
999 .brand = ELFOSABI_LINUX,
1000 .machine = EM_386,
1001 .compat_3_brand = "Linux",
1002 .emul_path = linux_emul_path,
1003 .interp_path = "/lib/ld-linux.so.2",
1004 .sysvec = &elf_linux_sysvec,
1005 .interp_newpath = NULL,
1006 .brand_note = &linux_brandnote,
1007 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
1008 };
1009
1010 static Elf32_Brandinfo linux_muslbrand = {
1011 .brand = ELFOSABI_LINUX,
1012 .machine = EM_386,
1013 .compat_3_brand = "Linux",
1014 .emul_path = linux_emul_path,
1015 .interp_path = "/lib/ld-musl-i386.so.1",
1016 .sysvec = &elf_linux_sysvec,
1017 .interp_newpath = NULL,
1018 .brand_note = &linux_brandnote,
1019 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
1020 };
1021
1022 Elf32_Brandinfo *linux_brandlist[] = {
1023 &linux_brand,
1024 &linux_glibc2brand,
1025 &linux_muslbrand,
1026 NULL
1027 };
1028
1029 static int
1030 linux_elf_modevent(module_t mod, int type, void *data)
1031 {
1032 Elf32_Brandinfo **brandinfo;
1033 int error;
1034 struct linux_ioctl_handler **lihp;
1035
1036 error = 0;
1037
1038 switch(type) {
1039 case MOD_LOAD:
1040 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1041 ++brandinfo)
1042 if (elf32_insert_brand_entry(*brandinfo) < 0)
1043 error = EINVAL;
1044 if (error == 0) {
1045 SET_FOREACH(lihp, linux_ioctl_handler_set)
1046 linux_ioctl_register_handler(*lihp);
1047 LIST_INIT(&futex_list);
1048 mtx_init(&futex_mtx, "ftllk", NULL, MTX_DEF);
1049 linux_get_machine(&linux_kplatform);
1050 linux_szplatform = roundup(strlen(linux_kplatform) + 1,
1051 sizeof(char *));
1052 linux_dev_shm_create();
1053 linux_osd_jail_register();
1054 stclohz = (stathz ? stathz : hz);
1055 if (bootverbose)
1056 printf("Linux ELF exec handler installed\n");
1057 } else
1058 printf("cannot insert Linux ELF brand handler\n");
1059 break;
1060 case MOD_UNLOAD:
1061 for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
1062 ++brandinfo)
1063 if (elf32_brand_inuse(*brandinfo))
1064 error = EBUSY;
1065 if (error == 0) {
1066 for (brandinfo = &linux_brandlist[0];
1067 *brandinfo != NULL; ++brandinfo)
1068 if (elf32_remove_brand_entry(*brandinfo) < 0)
1069 error = EINVAL;
1070 }
1071 if (error == 0) {
1072 SET_FOREACH(lihp, linux_ioctl_handler_set)
1073 linux_ioctl_unregister_handler(*lihp);
1074 mtx_destroy(&futex_mtx);
1075 linux_dev_shm_destroy();
1076 linux_osd_jail_deregister();
1077 if (bootverbose)
1078 printf("Linux ELF exec handler removed\n");
1079 } else
1080 printf("Could not deinstall ELF interpreter entry\n");
1081 break;
1082 default:
1083 return (EOPNOTSUPP);
1084 }
1085 return (error);
1086 }
1087
1088 static moduledata_t linux_elf_mod = {
1089 "linuxelf",
1090 linux_elf_modevent,
1091 0
1092 };
1093
1094 DECLARE_MODULE_TIED(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
1095 FEATURE(linux, "Linux 32bit support");
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