Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/binfmt_flat.c
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1 /****************************************************************************/ 2 /* 3 * linux/fs/binfmt_flat.c 4 * 5 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com> 6 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com> 7 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com> 8 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com> 9 * based heavily on: 10 * 11 * linux/fs/binfmt_aout.c: 12 * Copyright (C) 1991, 1992, 1996 Linus Torvalds 13 * linux/fs/binfmt_flat.c for 2.0 kernel 14 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com> 15 * JAN/99 -- coded full program relocation (gerg@snapgear.com) 16 */ 17 18 #include <linux/export.h> 19 #include <linux/kernel.h> 20 #include <linux/sched.h> 21 #include <linux/mm.h> 22 #include <linux/mman.h> 23 #include <linux/errno.h> 24 #include <linux/signal.h> 25 #include <linux/string.h> 26 #include <linux/fs.h> 27 #include <linux/file.h> 28 #include <linux/stat.h> 29 #include <linux/fcntl.h> 30 #include <linux/ptrace.h> 31 #include <linux/user.h> 32 #include <linux/slab.h> 33 #include <linux/binfmts.h> 34 #include <linux/personality.h> 35 #include <linux/init.h> 36 #include <linux/flat.h> 37 #include <linux/syscalls.h> 38 39 #include <asm/byteorder.h> 40 #include <asm/uaccess.h> 41 #include <asm/unaligned.h> 42 #include <asm/cacheflush.h> 43 #include <asm/page.h> 44 45 /****************************************************************************/ 46 47 #if 0 48 #define DEBUG 1 49 #endif 50 51 #ifdef DEBUG 52 #define DBG_FLT(a...) printk(a) 53 #else 54 #define DBG_FLT(a...) 55 #endif 56 57 /* 58 * User data (data section and bss) needs to be aligned. 59 * We pick 0x20 here because it is the max value elf2flt has always 60 * used in producing FLAT files, and because it seems to be large 61 * enough to make all the gcc alignment related tests happy. 62 */ 63 #define FLAT_DATA_ALIGN (0x20) 64 65 /* 66 * User data (stack) also needs to be aligned. 67 * Here we can be a bit looser than the data sections since this 68 * needs to only meet arch ABI requirements. 69 */ 70 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) 71 72 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ 73 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ 74 75 struct lib_info { 76 struct { 77 unsigned long start_code; /* Start of text segment */ 78 unsigned long start_data; /* Start of data segment */ 79 unsigned long start_brk; /* End of data segment */ 80 unsigned long text_len; /* Length of text segment */ 81 unsigned long entry; /* Start address for this module */ 82 unsigned long build_date; /* When this one was compiled */ 83 short loaded; /* Has this library been loaded? */ 84 } lib_list[MAX_SHARED_LIBS]; 85 }; 86 87 #ifdef CONFIG_BINFMT_SHARED_FLAT 88 static int load_flat_shared_library(int id, struct lib_info *p); 89 #endif 90 91 static int load_flat_binary(struct linux_binprm *); 92 static int flat_core_dump(struct coredump_params *cprm); 93 94 static struct linux_binfmt flat_format = { 95 .module = THIS_MODULE, 96 .load_binary = load_flat_binary, 97 .core_dump = flat_core_dump, 98 .min_coredump = PAGE_SIZE 99 }; 100 101 /****************************************************************************/ 102 /* 103 * Routine writes a core dump image in the current directory. 104 * Currently only a stub-function. 105 */ 106 107 static int flat_core_dump(struct coredump_params *cprm) 108 { 109 printk("Process %s:%d received signr %d and should have core dumped\n", 110 current->comm, current->pid, (int) cprm->siginfo->si_signo); 111 return(1); 112 } 113 114 /****************************************************************************/ 115 /* 116 * create_flat_tables() parses the env- and arg-strings in new user 117 * memory and creates the pointer tables from them, and puts their 118 * addresses on the "stack", returning the new stack pointer value. 119 */ 120 121 static unsigned long create_flat_tables( 122 unsigned long pp, 123 struct linux_binprm * bprm) 124 { 125 unsigned long *argv,*envp; 126 unsigned long * sp; 127 char * p = (char*)pp; 128 int argc = bprm->argc; 129 int envc = bprm->envc; 130 char uninitialized_var(dummy); 131 132 sp = (unsigned long *)p; 133 sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); 134 sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN); 135 argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0); 136 envp = argv + (argc + 1); 137 138 if (flat_argvp_envp_on_stack()) { 139 put_user((unsigned long) envp, sp + 2); 140 put_user((unsigned long) argv, sp + 1); 141 } 142 143 put_user(argc, sp); 144 current->mm->arg_start = (unsigned long) p; 145 while (argc-->0) { 146 put_user((unsigned long) p, argv++); 147 do { 148 get_user(dummy, p); p++; 149 } while (dummy); 150 } 151 put_user((unsigned long) NULL, argv); 152 current->mm->arg_end = current->mm->env_start = (unsigned long) p; 153 while (envc-->0) { 154 put_user((unsigned long)p, envp); envp++; 155 do { 156 get_user(dummy, p); p++; 157 } while (dummy); 158 } 159 put_user((unsigned long) NULL, envp); 160 current->mm->env_end = (unsigned long) p; 161 return (unsigned long)sp; 162 } 163 164 /****************************************************************************/ 165 166 #ifdef CONFIG_BINFMT_ZFLAT 167 168 #include <linux/zlib.h> 169 170 #define LBUFSIZE 4000 171 172 /* gzip flag byte */ 173 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 174 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 175 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 176 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 177 #define COMMENT 0x10 /* bit 4 set: file comment present */ 178 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 179 #define RESERVED 0xC0 /* bit 6,7: reserved */ 180 181 static int decompress_exec( 182 struct linux_binprm *bprm, 183 unsigned long offset, 184 char *dst, 185 long len, 186 int fd) 187 { 188 unsigned char *buf; 189 z_stream strm; 190 loff_t fpos; 191 int ret, retval; 192 193 DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len); 194 195 memset(&strm, 0, sizeof(strm)); 196 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); 197 if (strm.workspace == NULL) { 198 DBG_FLT("binfmt_flat: no memory for decompress workspace\n"); 199 return -ENOMEM; 200 } 201 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 202 if (buf == NULL) { 203 DBG_FLT("binfmt_flat: no memory for read buffer\n"); 204 retval = -ENOMEM; 205 goto out_free; 206 } 207 208 /* Read in first chunk of data and parse gzip header. */ 209 fpos = offset; 210 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos); 211 212 strm.next_in = buf; 213 strm.avail_in = ret; 214 strm.total_in = 0; 215 216 retval = -ENOEXEC; 217 218 /* Check minimum size -- gzip header */ 219 if (ret < 10) { 220 DBG_FLT("binfmt_flat: file too small?\n"); 221 goto out_free_buf; 222 } 223 224 /* Check gzip magic number */ 225 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 226 DBG_FLT("binfmt_flat: unknown compression magic?\n"); 227 goto out_free_buf; 228 } 229 230 /* Check gzip method */ 231 if (buf[2] != 8) { 232 DBG_FLT("binfmt_flat: unknown compression method?\n"); 233 goto out_free_buf; 234 } 235 /* Check gzip flags */ 236 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 237 (buf[3] & RESERVED)) { 238 DBG_FLT("binfmt_flat: unknown flags?\n"); 239 goto out_free_buf; 240 } 241 242 ret = 10; 243 if (buf[3] & EXTRA_FIELD) { 244 ret += 2 + buf[10] + (buf[11] << 8); 245 if (unlikely(LBUFSIZE <= ret)) { 246 DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n"); 247 goto out_free_buf; 248 } 249 } 250 if (buf[3] & ORIG_NAME) { 251 while (ret < LBUFSIZE && buf[ret++] != 0) 252 ; 253 if (unlikely(LBUFSIZE == ret)) { 254 DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n"); 255 goto out_free_buf; 256 } 257 } 258 if (buf[3] & COMMENT) { 259 while (ret < LBUFSIZE && buf[ret++] != 0) 260 ; 261 if (unlikely(LBUFSIZE == ret)) { 262 DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n"); 263 goto out_free_buf; 264 } 265 } 266 267 strm.next_in += ret; 268 strm.avail_in -= ret; 269 270 strm.next_out = dst; 271 strm.avail_out = len; 272 strm.total_out = 0; 273 274 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 275 DBG_FLT("binfmt_flat: zlib init failed?\n"); 276 goto out_free_buf; 277 } 278 279 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 280 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos); 281 if (ret <= 0) 282 break; 283 len -= ret; 284 285 strm.next_in = buf; 286 strm.avail_in = ret; 287 strm.total_in = 0; 288 } 289 290 if (ret < 0) { 291 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n", 292 ret, strm.msg); 293 goto out_zlib; 294 } 295 296 retval = 0; 297 out_zlib: 298 zlib_inflateEnd(&strm); 299 out_free_buf: 300 kfree(buf); 301 out_free: 302 kfree(strm.workspace); 303 return retval; 304 } 305 306 #endif /* CONFIG_BINFMT_ZFLAT */ 307 308 /****************************************************************************/ 309 310 static unsigned long 311 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) 312 { 313 unsigned long addr; 314 int id; 315 unsigned long start_brk; 316 unsigned long start_data; 317 unsigned long text_len; 318 unsigned long start_code; 319 320 #ifdef CONFIG_BINFMT_SHARED_FLAT 321 if (r == 0) 322 id = curid; /* Relocs of 0 are always self referring */ 323 else { 324 id = (r >> 24) & 0xff; /* Find ID for this reloc */ 325 r &= 0x00ffffff; /* Trim ID off here */ 326 } 327 if (id >= MAX_SHARED_LIBS) { 328 printk("BINFMT_FLAT: reference 0x%x to shared library %d", 329 (unsigned) r, id); 330 goto failed; 331 } 332 if (curid != id) { 333 if (internalp) { 334 printk("BINFMT_FLAT: reloc address 0x%x not in same module " 335 "(%d != %d)", (unsigned) r, curid, id); 336 goto failed; 337 } else if ( ! p->lib_list[id].loaded && 338 IS_ERR_VALUE(load_flat_shared_library(id, p))) { 339 printk("BINFMT_FLAT: failed to load library %d", id); 340 goto failed; 341 } 342 /* Check versioning information (i.e. time stamps) */ 343 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 344 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 345 printk("BINFMT_FLAT: library %d is younger than %d", id, curid); 346 goto failed; 347 } 348 } 349 #else 350 id = 0; 351 #endif 352 353 start_brk = p->lib_list[id].start_brk; 354 start_data = p->lib_list[id].start_data; 355 start_code = p->lib_list[id].start_code; 356 text_len = p->lib_list[id].text_len; 357 358 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { 359 printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)", 360 (int) r,(int)(start_brk-start_data+text_len),(int)text_len); 361 goto failed; 362 } 363 364 if (r < text_len) /* In text segment */ 365 addr = r + start_code; 366 else /* In data segment */ 367 addr = r - text_len + start_data; 368 369 /* Range checked already above so doing the range tests is redundant...*/ 370 return(addr); 371 372 failed: 373 printk(", killing %s!\n", current->comm); 374 send_sig(SIGSEGV, current, 0); 375 376 return RELOC_FAILED; 377 } 378 379 /****************************************************************************/ 380 381 void old_reloc(unsigned long rl) 382 { 383 #ifdef DEBUG 384 char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 385 #endif 386 flat_v2_reloc_t r; 387 unsigned long *ptr; 388 389 r.value = rl; 390 #if defined(CONFIG_COLDFIRE) 391 ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset); 392 #else 393 ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset); 394 #endif 395 396 #ifdef DEBUG 397 printk("Relocation of variable at DATASEG+%x " 398 "(address %p, currently %x) into segment %s\n", 399 r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]); 400 #endif 401 402 switch (r.reloc.type) { 403 case OLD_FLAT_RELOC_TYPE_TEXT: 404 *ptr += current->mm->start_code; 405 break; 406 case OLD_FLAT_RELOC_TYPE_DATA: 407 *ptr += current->mm->start_data; 408 break; 409 case OLD_FLAT_RELOC_TYPE_BSS: 410 *ptr += current->mm->end_data; 411 break; 412 default: 413 printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type); 414 break; 415 } 416 417 #ifdef DEBUG 418 printk("Relocation became %x\n", (int)*ptr); 419 #endif 420 } 421 422 /****************************************************************************/ 423 424 static int load_flat_file(struct linux_binprm * bprm, 425 struct lib_info *libinfo, int id, unsigned long *extra_stack) 426 { 427 struct flat_hdr * hdr; 428 unsigned long textpos = 0, datapos = 0, result; 429 unsigned long realdatastart = 0; 430 unsigned long text_len, data_len, bss_len, stack_len, flags; 431 unsigned long len, memp = 0; 432 unsigned long memp_size, extra, rlim; 433 unsigned long *reloc = 0, *rp; 434 struct inode *inode; 435 int i, rev, relocs = 0; 436 loff_t fpos; 437 unsigned long start_code, end_code; 438 int ret; 439 440 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 441 inode = bprm->file->f_path.dentry->d_inode; 442 443 text_len = ntohl(hdr->data_start); 444 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 445 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 446 stack_len = ntohl(hdr->stack_size); 447 if (extra_stack) { 448 stack_len += *extra_stack; 449 *extra_stack = stack_len; 450 } 451 relocs = ntohl(hdr->reloc_count); 452 flags = ntohl(hdr->flags); 453 rev = ntohl(hdr->rev); 454 455 if (strncmp(hdr->magic, "bFLT", 4)) { 456 /* 457 * Previously, here was a printk to tell people 458 * "BINFMT_FLAT: bad header magic". 459 * But for the kernel which also use ELF FD-PIC format, this 460 * error message is confusing. 461 * because a lot of people do not manage to produce good 462 */ 463 ret = -ENOEXEC; 464 goto err; 465 } 466 467 if (flags & FLAT_FLAG_KTRACE) 468 printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename); 469 470 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 471 printk("BINFMT_FLAT: bad flat file version 0x%x (supported " 472 "0x%lx and 0x%lx)\n", 473 rev, FLAT_VERSION, OLD_FLAT_VERSION); 474 ret = -ENOEXEC; 475 goto err; 476 } 477 478 /* Don't allow old format executables to use shared libraries */ 479 if (rev == OLD_FLAT_VERSION && id != 0) { 480 printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n", 481 (int) FLAT_VERSION); 482 ret = -ENOEXEC; 483 goto err; 484 } 485 486 /* 487 * fix up the flags for the older format, there were all kinds 488 * of endian hacks, this only works for the simple cases 489 */ 490 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) 491 flags = FLAT_FLAG_RAM; 492 493 #ifndef CONFIG_BINFMT_ZFLAT 494 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 495 printk("Support for ZFLAT executables is not enabled.\n"); 496 ret = -ENOEXEC; 497 goto err; 498 } 499 #endif 500 501 /* 502 * Check initial limits. This avoids letting people circumvent 503 * size limits imposed on them by creating programs with large 504 * arrays in the data or bss. 505 */ 506 rlim = rlimit(RLIMIT_DATA); 507 if (rlim >= RLIM_INFINITY) 508 rlim = ~0; 509 if (data_len + bss_len > rlim) { 510 ret = -ENOMEM; 511 goto err; 512 } 513 514 /* Flush all traces of the currently running executable */ 515 if (id == 0) { 516 result = flush_old_exec(bprm); 517 if (result) { 518 ret = result; 519 goto err; 520 } 521 522 /* OK, This is the point of no return */ 523 set_personality(PER_LINUX_32BIT); 524 setup_new_exec(bprm); 525 } 526 527 /* 528 * calculate the extra space we need to map in 529 */ 530 extra = max_t(unsigned long, bss_len + stack_len, 531 relocs * sizeof(unsigned long)); 532 533 /* 534 * there are a couple of cases here, the separate code/data 535 * case, and then the fully copied to RAM case which lumps 536 * it all together. 537 */ 538 if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) { 539 /* 540 * this should give us a ROM ptr, but if it doesn't we don't 541 * really care 542 */ 543 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n"); 544 545 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 546 MAP_PRIVATE|MAP_EXECUTABLE, 0); 547 if (!textpos || IS_ERR_VALUE(textpos)) { 548 if (!textpos) 549 textpos = (unsigned long) -ENOMEM; 550 printk("Unable to mmap process text, errno %d\n", (int)-textpos); 551 ret = textpos; 552 goto err; 553 } 554 555 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 556 len = PAGE_ALIGN(len); 557 realdatastart = vm_mmap(0, 0, len, 558 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 559 560 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 561 if (!realdatastart) 562 realdatastart = (unsigned long) -ENOMEM; 563 printk("Unable to allocate RAM for process data, errno %d\n", 564 (int)-realdatastart); 565 vm_munmap(textpos, text_len); 566 ret = realdatastart; 567 goto err; 568 } 569 datapos = ALIGN(realdatastart + 570 MAX_SHARED_LIBS * sizeof(unsigned long), 571 FLAT_DATA_ALIGN); 572 573 DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n", 574 (int)(data_len + bss_len + stack_len), (int)datapos); 575 576 fpos = ntohl(hdr->data_start); 577 #ifdef CONFIG_BINFMT_ZFLAT 578 if (flags & FLAT_FLAG_GZDATA) { 579 result = decompress_exec(bprm, fpos, (char *) datapos, 580 data_len + (relocs * sizeof(unsigned long)), 0); 581 } else 582 #endif 583 { 584 result = bprm->file->f_op->read(bprm->file, (char *) datapos, 585 data_len + (relocs * sizeof(unsigned long)), &fpos); 586 } 587 if (IS_ERR_VALUE(result)) { 588 printk("Unable to read data+bss, errno %d\n", (int)-result); 589 vm_munmap(textpos, text_len); 590 vm_munmap(realdatastart, len); 591 ret = result; 592 goto err; 593 } 594 595 reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len)); 596 memp = realdatastart; 597 memp_size = len; 598 } else { 599 600 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 601 len = PAGE_ALIGN(len); 602 textpos = vm_mmap(0, 0, len, 603 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 604 605 if (!textpos || IS_ERR_VALUE(textpos)) { 606 if (!textpos) 607 textpos = (unsigned long) -ENOMEM; 608 printk("Unable to allocate RAM for process text/data, errno %d\n", 609 (int)-textpos); 610 ret = textpos; 611 goto err; 612 } 613 614 realdatastart = textpos + ntohl(hdr->data_start); 615 datapos = ALIGN(realdatastart + 616 MAX_SHARED_LIBS * sizeof(unsigned long), 617 FLAT_DATA_ALIGN); 618 619 reloc = (unsigned long *) 620 (datapos + (ntohl(hdr->reloc_start) - text_len)); 621 memp = textpos; 622 memp_size = len; 623 #ifdef CONFIG_BINFMT_ZFLAT 624 /* 625 * load it all in and treat it like a RAM load from now on 626 */ 627 if (flags & FLAT_FLAG_GZIP) { 628 result = decompress_exec(bprm, sizeof (struct flat_hdr), 629 (((char *) textpos) + sizeof (struct flat_hdr)), 630 (text_len + data_len + (relocs * sizeof(unsigned long)) 631 - sizeof (struct flat_hdr)), 632 0); 633 memmove((void *) datapos, (void *) realdatastart, 634 data_len + (relocs * sizeof(unsigned long))); 635 } else if (flags & FLAT_FLAG_GZDATA) { 636 fpos = 0; 637 result = bprm->file->f_op->read(bprm->file, 638 (char *) textpos, text_len, &fpos); 639 if (!IS_ERR_VALUE(result)) 640 result = decompress_exec(bprm, text_len, (char *) datapos, 641 data_len + (relocs * sizeof(unsigned long)), 0); 642 } 643 else 644 #endif 645 { 646 fpos = 0; 647 result = bprm->file->f_op->read(bprm->file, 648 (char *) textpos, text_len, &fpos); 649 if (!IS_ERR_VALUE(result)) { 650 fpos = ntohl(hdr->data_start); 651 result = bprm->file->f_op->read(bprm->file, (char *) datapos, 652 data_len + (relocs * sizeof(unsigned long)), &fpos); 653 } 654 } 655 if (IS_ERR_VALUE(result)) { 656 printk("Unable to read code+data+bss, errno %d\n",(int)-result); 657 vm_munmap(textpos, text_len + data_len + extra + 658 MAX_SHARED_LIBS * sizeof(unsigned long)); 659 ret = result; 660 goto err; 661 } 662 } 663 664 if (flags & FLAT_FLAG_KTRACE) 665 printk("Mapping is %x, Entry point is %x, data_start is %x\n", 666 (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 667 668 /* The main program needs a little extra setup in the task structure */ 669 start_code = textpos + sizeof (struct flat_hdr); 670 end_code = textpos + text_len; 671 if (id == 0) { 672 current->mm->start_code = start_code; 673 current->mm->end_code = end_code; 674 current->mm->start_data = datapos; 675 current->mm->end_data = datapos + data_len; 676 /* 677 * set up the brk stuff, uses any slack left in data/bss/stack 678 * allocation. We put the brk after the bss (between the bss 679 * and stack) like other platforms. 680 * Userspace code relies on the stack pointer starting out at 681 * an address right at the end of a page. 682 */ 683 current->mm->start_brk = datapos + data_len + bss_len; 684 current->mm->brk = (current->mm->start_brk + 3) & ~3; 685 current->mm->context.end_brk = memp + memp_size - stack_len; 686 } 687 688 if (flags & FLAT_FLAG_KTRACE) 689 printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n", 690 id ? "Lib" : "Load", bprm->filename, 691 (int) start_code, (int) end_code, 692 (int) datapos, 693 (int) (datapos + data_len), 694 (int) (datapos + data_len), 695 (int) (((datapos + data_len + bss_len) + 3) & ~3)); 696 697 text_len -= sizeof(struct flat_hdr); /* the real code len */ 698 699 /* Store the current module values into the global library structure */ 700 libinfo->lib_list[id].start_code = start_code; 701 libinfo->lib_list[id].start_data = datapos; 702 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 703 libinfo->lib_list[id].text_len = text_len; 704 libinfo->lib_list[id].loaded = 1; 705 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 706 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 707 708 /* 709 * We just load the allocations into some temporary memory to 710 * help simplify all this mumbo jumbo 711 * 712 * We've got two different sections of relocation entries. 713 * The first is the GOT which resides at the beginning of the data segment 714 * and is terminated with a -1. This one can be relocated in place. 715 * The second is the extra relocation entries tacked after the image's 716 * data segment. These require a little more processing as the entry is 717 * really an offset into the image which contains an offset into the 718 * image. 719 */ 720 if (flags & FLAT_FLAG_GOTPIC) { 721 for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) { 722 unsigned long addr; 723 if (*rp) { 724 addr = calc_reloc(*rp, libinfo, id, 0); 725 if (addr == RELOC_FAILED) { 726 ret = -ENOEXEC; 727 goto err; 728 } 729 *rp = addr; 730 } 731 } 732 } 733 734 /* 735 * Now run through the relocation entries. 736 * We've got to be careful here as C++ produces relocatable zero 737 * entries in the constructor and destructor tables which are then 738 * tested for being not zero (which will always occur unless we're 739 * based from address zero). This causes an endless loop as __start 740 * is at zero. The solution used is to not relocate zero addresses. 741 * This has the negative side effect of not allowing a global data 742 * reference to be statically initialised to _stext (I've moved 743 * __start to address 4 so that is okay). 744 */ 745 if (rev > OLD_FLAT_VERSION) { 746 unsigned long persistent = 0; 747 for (i=0; i < relocs; i++) { 748 unsigned long addr, relval; 749 750 /* Get the address of the pointer to be 751 relocated (of course, the address has to be 752 relocated first). */ 753 relval = ntohl(reloc[i]); 754 if (flat_set_persistent (relval, &persistent)) 755 continue; 756 addr = flat_get_relocate_addr(relval); 757 rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1); 758 if (rp == (unsigned long *)RELOC_FAILED) { 759 ret = -ENOEXEC; 760 goto err; 761 } 762 763 /* Get the pointer's value. */ 764 addr = flat_get_addr_from_rp(rp, relval, flags, 765 &persistent); 766 if (addr != 0) { 767 /* 768 * Do the relocation. PIC relocs in the data section are 769 * already in target order 770 */ 771 if ((flags & FLAT_FLAG_GOTPIC) == 0) 772 addr = ntohl(addr); 773 addr = calc_reloc(addr, libinfo, id, 0); 774 if (addr == RELOC_FAILED) { 775 ret = -ENOEXEC; 776 goto err; 777 } 778 779 /* Write back the relocated pointer. */ 780 flat_put_addr_at_rp(rp, addr, relval); 781 } 782 } 783 } else { 784 for (i=0; i < relocs; i++) 785 old_reloc(ntohl(reloc[i])); 786 } 787 788 flush_icache_range(start_code, end_code); 789 790 /* zero the BSS, BRK and stack areas */ 791 memset((void*)(datapos + data_len), 0, bss_len + 792 (memp + memp_size - stack_len - /* end brk */ 793 libinfo->lib_list[id].start_brk) + /* start brk */ 794 stack_len); 795 796 return 0; 797 err: 798 return ret; 799 } 800 801 802 /****************************************************************************/ 803 #ifdef CONFIG_BINFMT_SHARED_FLAT 804 805 /* 806 * Load a shared library into memory. The library gets its own data 807 * segment (including bss) but not argv/argc/environ. 808 */ 809 810 static int load_flat_shared_library(int id, struct lib_info *libs) 811 { 812 struct linux_binprm bprm; 813 int res; 814 char buf[16]; 815 816 memset(&bprm, 0, sizeof(bprm)); 817 818 /* Create the file name */ 819 sprintf(buf, "/lib/lib%d.so", id); 820 821 /* Open the file up */ 822 bprm.filename = buf; 823 bprm.file = open_exec(bprm.filename); 824 res = PTR_ERR(bprm.file); 825 if (IS_ERR(bprm.file)) 826 return res; 827 828 bprm.cred = prepare_exec_creds(); 829 res = -ENOMEM; 830 if (!bprm.cred) 831 goto out; 832 833 /* We don't really care about recalculating credentials at this point 834 * as we're past the point of no return and are dealing with shared 835 * libraries. 836 */ 837 bprm.cred_prepared = 1; 838 839 res = prepare_binprm(&bprm); 840 841 if (!IS_ERR_VALUE(res)) 842 res = load_flat_file(&bprm, libs, id, NULL); 843 844 abort_creds(bprm.cred); 845 846 out: 847 allow_write_access(bprm.file); 848 fput(bprm.file); 849 850 return(res); 851 } 852 853 #endif /* CONFIG_BINFMT_SHARED_FLAT */ 854 /****************************************************************************/ 855 856 /* 857 * These are the functions used to load flat style executables and shared 858 * libraries. There is no binary dependent code anywhere else. 859 */ 860 861 static int load_flat_binary(struct linux_binprm * bprm) 862 { 863 struct lib_info libinfo; 864 struct pt_regs *regs = current_pt_regs(); 865 unsigned long p = bprm->p; 866 unsigned long stack_len; 867 unsigned long start_addr; 868 unsigned long *sp; 869 int res; 870 int i, j; 871 872 memset(&libinfo, 0, sizeof(libinfo)); 873 /* 874 * We have to add the size of our arguments to our stack size 875 * otherwise it's too easy for users to create stack overflows 876 * by passing in a huge argument list. And yes, we have to be 877 * pedantic and include space for the argv/envp array as it may have 878 * a lot of entries. 879 */ 880 #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *)) 881 stack_len = TOP_OF_ARGS - bprm->p; /* the strings */ 882 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 883 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 884 stack_len += FLAT_STACK_ALIGN - 1; /* reserve for upcoming alignment */ 885 886 res = load_flat_file(bprm, &libinfo, 0, &stack_len); 887 if (IS_ERR_VALUE(res)) 888 return res; 889 890 /* Update data segment pointers for all libraries */ 891 for (i=0; i<MAX_SHARED_LIBS; i++) 892 if (libinfo.lib_list[i].loaded) 893 for (j=0; j<MAX_SHARED_LIBS; j++) 894 (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] = 895 (libinfo.lib_list[j].loaded)? 896 libinfo.lib_list[j].start_data:UNLOADED_LIB; 897 898 install_exec_creds(bprm); 899 900 set_binfmt(&flat_format); 901 902 p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 903 DBG_FLT("p=%x\n", (int)p); 904 905 /* copy the arg pages onto the stack, this could be more efficient :-) */ 906 for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--) 907 * (char *) --p = 908 ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE]; 909 910 sp = (unsigned long *) create_flat_tables(p, bprm); 911 912 /* Fake some return addresses to ensure the call chain will 913 * initialise library in order for us. We are required to call 914 * lib 1 first, then 2, ... and finally the main program (id 0). 915 */ 916 start_addr = libinfo.lib_list[0].entry; 917 918 #ifdef CONFIG_BINFMT_SHARED_FLAT 919 for (i = MAX_SHARED_LIBS-1; i>0; i--) { 920 if (libinfo.lib_list[i].loaded) { 921 /* Push previos first to call address */ 922 --sp; put_user(start_addr, sp); 923 start_addr = libinfo.lib_list[i].entry; 924 } 925 } 926 #endif 927 928 /* Stash our initial stack pointer into the mm structure */ 929 current->mm->start_stack = (unsigned long )sp; 930 931 #ifdef FLAT_PLAT_INIT 932 FLAT_PLAT_INIT(regs); 933 #endif 934 DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n", 935 (int)regs, (int)start_addr, (int)current->mm->start_stack); 936 937 start_thread(regs, start_addr, current->mm->start_stack); 938 939 return 0; 940 } 941 942 /****************************************************************************/ 943 944 static int __init init_flat_binfmt(void) 945 { 946 register_binfmt(&flat_format); 947 return 0; 948 } 949 950 /****************************************************************************/ 951 952 core_initcall(init_flat_binfmt); 953 954 /****************************************************************************/
Cache object: 3203b2aa3dad962b2e401230d869d23a
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