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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 19 20 #include <linux/kernel.h> 21 #include <linux/sched.h> 22 #include <linux/sched/task_stack.h> 23 #include <linux/mm.h> 24 #include <linux/mman.h> 25 #include <linux/errno.h> 26 #include <linux/signal.h> 27 #include <linux/string.h> 28 #include <linux/fs.h> 29 #include <linux/file.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/uaccess.h> 38 #include <linux/vmalloc.h> 39 40 #include <asm/byteorder.h> 41 #include <asm/unaligned.h> 42 #include <asm/cacheflush.h> 43 #include <asm/page.h> 44 45 /****************************************************************************/ 46 47 /* 48 * User data (data section and bss) needs to be aligned. 49 * We pick 0x20 here because it is the max value elf2flt has always 50 * used in producing FLAT files, and because it seems to be large 51 * enough to make all the gcc alignment related tests happy. 52 */ 53 #define FLAT_DATA_ALIGN (0x20) 54 55 /* 56 * User data (stack) also needs to be aligned. 57 * Here we can be a bit looser than the data sections since this 58 * needs to only meet arch ABI requirements. 59 */ 60 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) 61 62 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ 63 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ 64 65 struct lib_info { 66 struct { 67 unsigned long start_code; /* Start of text segment */ 68 unsigned long start_data; /* Start of data segment */ 69 unsigned long start_brk; /* End of data segment */ 70 unsigned long text_len; /* Length of text segment */ 71 unsigned long entry; /* Start address for this module */ 72 unsigned long build_date; /* When this one was compiled */ 73 bool loaded; /* Has this library been loaded? */ 74 } lib_list[MAX_SHARED_LIBS]; 75 }; 76 77 #ifdef CONFIG_BINFMT_SHARED_FLAT 78 static int load_flat_shared_library(int id, struct lib_info *p); 79 #endif 80 81 static int load_flat_binary(struct linux_binprm *); 82 static int flat_core_dump(struct coredump_params *cprm); 83 84 static struct linux_binfmt flat_format = { 85 .module = THIS_MODULE, 86 .load_binary = load_flat_binary, 87 .core_dump = flat_core_dump, 88 .min_coredump = PAGE_SIZE 89 }; 90 91 /****************************************************************************/ 92 /* 93 * Routine writes a core dump image in the current directory. 94 * Currently only a stub-function. 95 */ 96 97 static int flat_core_dump(struct coredump_params *cprm) 98 { 99 pr_warn("Process %s:%d received signr %d and should have core dumped\n", 100 current->comm, current->pid, cprm->siginfo->si_signo); 101 return 1; 102 } 103 104 /****************************************************************************/ 105 /* 106 * create_flat_tables() parses the env- and arg-strings in new user 107 * memory and creates the pointer tables from them, and puts their 108 * addresses on the "stack", recording the new stack pointer value. 109 */ 110 111 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start) 112 { 113 char __user *p; 114 unsigned long __user *sp; 115 long i, len; 116 117 p = (char __user *)arg_start; 118 sp = (unsigned long __user *)current->mm->start_stack; 119 120 sp -= bprm->envc + 1; 121 sp -= bprm->argc + 1; 122 sp -= flat_argvp_envp_on_stack() ? 2 : 0; 123 sp -= 1; /* &argc */ 124 125 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN; 126 sp = (unsigned long __user *)current->mm->start_stack; 127 128 __put_user(bprm->argc, sp++); 129 if (flat_argvp_envp_on_stack()) { 130 unsigned long argv, envp; 131 argv = (unsigned long)(sp + 2); 132 envp = (unsigned long)(sp + 2 + bprm->argc + 1); 133 __put_user(argv, sp++); 134 __put_user(envp, sp++); 135 } 136 137 current->mm->arg_start = (unsigned long)p; 138 for (i = bprm->argc; i > 0; i--) { 139 __put_user((unsigned long)p, sp++); 140 len = strnlen_user(p, MAX_ARG_STRLEN); 141 if (!len || len > MAX_ARG_STRLEN) 142 return -EINVAL; 143 p += len; 144 } 145 __put_user(0, sp++); 146 current->mm->arg_end = (unsigned long)p; 147 148 current->mm->env_start = (unsigned long) p; 149 for (i = bprm->envc; i > 0; i--) { 150 __put_user((unsigned long)p, sp++); 151 len = strnlen_user(p, MAX_ARG_STRLEN); 152 if (!len || len > MAX_ARG_STRLEN) 153 return -EINVAL; 154 p += len; 155 } 156 __put_user(0, sp++); 157 current->mm->env_end = (unsigned long)p; 158 159 return 0; 160 } 161 162 /****************************************************************************/ 163 164 #ifdef CONFIG_BINFMT_ZFLAT 165 166 #include <linux/zlib.h> 167 168 #define LBUFSIZE 4000 169 170 /* gzip flag byte */ 171 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 172 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 173 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 174 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 175 #define COMMENT 0x10 /* bit 4 set: file comment present */ 176 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 177 #define RESERVED 0xC0 /* bit 6,7: reserved */ 178 179 static int decompress_exec( 180 struct linux_binprm *bprm, 181 unsigned long offset, 182 char *dst, 183 long len, 184 int fd) 185 { 186 unsigned char *buf; 187 z_stream strm; 188 loff_t fpos; 189 int ret, retval; 190 191 pr_debug("decompress_exec(offset=%lx,buf=%p,len=%lx)\n", offset, dst, len); 192 193 memset(&strm, 0, sizeof(strm)); 194 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); 195 if (!strm.workspace) 196 return -ENOMEM; 197 198 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 199 if (!buf) { 200 retval = -ENOMEM; 201 goto out_free; 202 } 203 204 /* Read in first chunk of data and parse gzip header. */ 205 fpos = offset; 206 ret = kernel_read(bprm->file, offset, buf, LBUFSIZE); 207 208 strm.next_in = buf; 209 strm.avail_in = ret; 210 strm.total_in = 0; 211 fpos += ret; 212 213 retval = -ENOEXEC; 214 215 /* Check minimum size -- gzip header */ 216 if (ret < 10) { 217 pr_debug("file too small?\n"); 218 goto out_free_buf; 219 } 220 221 /* Check gzip magic number */ 222 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 223 pr_debug("unknown compression magic?\n"); 224 goto out_free_buf; 225 } 226 227 /* Check gzip method */ 228 if (buf[2] != 8) { 229 pr_debug("unknown compression method?\n"); 230 goto out_free_buf; 231 } 232 /* Check gzip flags */ 233 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 234 (buf[3] & RESERVED)) { 235 pr_debug("unknown flags?\n"); 236 goto out_free_buf; 237 } 238 239 ret = 10; 240 if (buf[3] & EXTRA_FIELD) { 241 ret += 2 + buf[10] + (buf[11] << 8); 242 if (unlikely(ret >= LBUFSIZE)) { 243 pr_debug("buffer overflow (EXTRA)?\n"); 244 goto out_free_buf; 245 } 246 } 247 if (buf[3] & ORIG_NAME) { 248 while (ret < LBUFSIZE && buf[ret++] != 0) 249 ; 250 if (unlikely(ret == LBUFSIZE)) { 251 pr_debug("buffer overflow (ORIG_NAME)?\n"); 252 goto out_free_buf; 253 } 254 } 255 if (buf[3] & COMMENT) { 256 while (ret < LBUFSIZE && buf[ret++] != 0) 257 ; 258 if (unlikely(ret == LBUFSIZE)) { 259 pr_debug("buffer overflow (COMMENT)?\n"); 260 goto out_free_buf; 261 } 262 } 263 264 strm.next_in += ret; 265 strm.avail_in -= ret; 266 267 strm.next_out = dst; 268 strm.avail_out = len; 269 strm.total_out = 0; 270 271 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 272 pr_debug("zlib init failed?\n"); 273 goto out_free_buf; 274 } 275 276 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 277 ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE); 278 if (ret <= 0) 279 break; 280 len -= ret; 281 282 strm.next_in = buf; 283 strm.avail_in = ret; 284 strm.total_in = 0; 285 fpos += ret; 286 } 287 288 if (ret < 0) { 289 pr_debug("decompression failed (%d), %s\n", 290 ret, strm.msg); 291 goto out_zlib; 292 } 293 294 retval = 0; 295 out_zlib: 296 zlib_inflateEnd(&strm); 297 out_free_buf: 298 kfree(buf); 299 out_free: 300 kfree(strm.workspace); 301 return retval; 302 } 303 304 #endif /* CONFIG_BINFMT_ZFLAT */ 305 306 /****************************************************************************/ 307 308 static unsigned long 309 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) 310 { 311 unsigned long addr; 312 int id; 313 unsigned long start_brk; 314 unsigned long start_data; 315 unsigned long text_len; 316 unsigned long start_code; 317 318 #ifdef CONFIG_BINFMT_SHARED_FLAT 319 if (r == 0) 320 id = curid; /* Relocs of 0 are always self referring */ 321 else { 322 id = (r >> 24) & 0xff; /* Find ID for this reloc */ 323 r &= 0x00ffffff; /* Trim ID off here */ 324 } 325 if (id >= MAX_SHARED_LIBS) { 326 pr_err("reference 0x%lx to shared library %d", r, id); 327 goto failed; 328 } 329 if (curid != id) { 330 if (internalp) { 331 pr_err("reloc address 0x%lx not in same module " 332 "(%d != %d)", r, curid, id); 333 goto failed; 334 } else if (!p->lib_list[id].loaded && 335 load_flat_shared_library(id, p) < 0) { 336 pr_err("failed to load library %d", id); 337 goto failed; 338 } 339 /* Check versioning information (i.e. time stamps) */ 340 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 341 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 342 pr_err("library %d is younger than %d", id, curid); 343 goto failed; 344 } 345 } 346 #else 347 id = 0; 348 #endif 349 350 start_brk = p->lib_list[id].start_brk; 351 start_data = p->lib_list[id].start_data; 352 start_code = p->lib_list[id].start_code; 353 text_len = p->lib_list[id].text_len; 354 355 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { 356 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", 357 r, start_brk-start_data+text_len, text_len); 358 goto failed; 359 } 360 361 if (r < text_len) /* In text segment */ 362 addr = r + start_code; 363 else /* In data segment */ 364 addr = r - text_len + start_data; 365 366 /* Range checked already above so doing the range tests is redundant...*/ 367 return addr; 368 369 failed: 370 pr_cont(", killing %s!\n", current->comm); 371 send_sig(SIGSEGV, current, 0); 372 373 return RELOC_FAILED; 374 } 375 376 /****************************************************************************/ 377 378 static void old_reloc(unsigned long rl) 379 { 380 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 381 flat_v2_reloc_t r; 382 unsigned long __user *ptr; 383 unsigned long val; 384 385 r.value = rl; 386 #if defined(CONFIG_COLDFIRE) 387 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); 388 #else 389 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); 390 #endif 391 get_user(val, ptr); 392 393 pr_debug("Relocation of variable at DATASEG+%x " 394 "(address %p, currently %lx) into segment %s\n", 395 r.reloc.offset, ptr, val, segment[r.reloc.type]); 396 397 switch (r.reloc.type) { 398 case OLD_FLAT_RELOC_TYPE_TEXT: 399 val += current->mm->start_code; 400 break; 401 case OLD_FLAT_RELOC_TYPE_DATA: 402 val += current->mm->start_data; 403 break; 404 case OLD_FLAT_RELOC_TYPE_BSS: 405 val += current->mm->end_data; 406 break; 407 default: 408 pr_err("Unknown relocation type=%x\n", r.reloc.type); 409 break; 410 } 411 put_user(val, ptr); 412 413 pr_debug("Relocation became %lx\n", val); 414 } 415 416 /****************************************************************************/ 417 418 static int load_flat_file(struct linux_binprm *bprm, 419 struct lib_info *libinfo, int id, unsigned long *extra_stack) 420 { 421 struct flat_hdr *hdr; 422 unsigned long textpos, datapos, realdatastart; 423 u32 text_len, data_len, bss_len, stack_len, full_data, flags; 424 unsigned long len, memp, memp_size, extra, rlim; 425 u32 __user *reloc, *rp; 426 struct inode *inode; 427 int i, rev, relocs; 428 loff_t fpos; 429 unsigned long start_code, end_code; 430 ssize_t result; 431 int ret; 432 433 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 434 inode = file_inode(bprm->file); 435 436 text_len = ntohl(hdr->data_start); 437 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 438 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 439 stack_len = ntohl(hdr->stack_size); 440 if (extra_stack) { 441 stack_len += *extra_stack; 442 *extra_stack = stack_len; 443 } 444 relocs = ntohl(hdr->reloc_count); 445 flags = ntohl(hdr->flags); 446 rev = ntohl(hdr->rev); 447 full_data = data_len + relocs * sizeof(unsigned long); 448 449 if (strncmp(hdr->magic, "bFLT", 4)) { 450 /* 451 * Previously, here was a printk to tell people 452 * "BINFMT_FLAT: bad header magic". 453 * But for the kernel which also use ELF FD-PIC format, this 454 * error message is confusing. 455 * because a lot of people do not manage to produce good 456 */ 457 ret = -ENOEXEC; 458 goto err; 459 } 460 461 if (flags & FLAT_FLAG_KTRACE) 462 pr_info("Loading file: %s\n", bprm->filename); 463 464 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 465 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", 466 rev, FLAT_VERSION, OLD_FLAT_VERSION); 467 ret = -ENOEXEC; 468 goto err; 469 } 470 471 /* Don't allow old format executables to use shared libraries */ 472 if (rev == OLD_FLAT_VERSION && id != 0) { 473 pr_err("shared libraries are not available before rev 0x%lx\n", 474 FLAT_VERSION); 475 ret = -ENOEXEC; 476 goto err; 477 } 478 479 /* 480 * Make sure the header params are sane. 481 * 28 bits (256 MB) is way more than reasonable in this case. 482 * If some top bits are set we have probable binary corruption. 483 */ 484 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { 485 pr_err("bad header\n"); 486 ret = -ENOEXEC; 487 goto err; 488 } 489 490 /* 491 * fix up the flags for the older format, there were all kinds 492 * of endian hacks, this only works for the simple cases 493 */ 494 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) 495 flags = FLAT_FLAG_RAM; 496 497 #ifndef CONFIG_BINFMT_ZFLAT 498 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 499 pr_err("Support for ZFLAT executables is not enabled.\n"); 500 ret = -ENOEXEC; 501 goto err; 502 } 503 #endif 504 505 /* 506 * Check initial limits. This avoids letting people circumvent 507 * size limits imposed on them by creating programs with large 508 * arrays in the data or bss. 509 */ 510 rlim = rlimit(RLIMIT_DATA); 511 if (rlim >= RLIM_INFINITY) 512 rlim = ~0; 513 if (data_len + bss_len > rlim) { 514 ret = -ENOMEM; 515 goto err; 516 } 517 518 /* Flush all traces of the currently running executable */ 519 if (id == 0) { 520 ret = flush_old_exec(bprm); 521 if (ret) 522 goto err; 523 524 /* OK, This is the point of no return */ 525 set_personality(PER_LINUX_32BIT); 526 setup_new_exec(bprm); 527 } 528 529 /* 530 * calculate the extra space we need to map in 531 */ 532 extra = max_t(unsigned long, bss_len + stack_len, 533 relocs * sizeof(unsigned long)); 534 535 /* 536 * there are a couple of cases here, the separate code/data 537 * case, and then the fully copied to RAM case which lumps 538 * it all together. 539 */ 540 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { 541 /* 542 * this should give us a ROM ptr, but if it doesn't we don't 543 * really care 544 */ 545 pr_debug("ROM mapping of file (we hope)\n"); 546 547 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 548 MAP_PRIVATE|MAP_EXECUTABLE, 0); 549 if (!textpos || IS_ERR_VALUE(textpos)) { 550 ret = textpos; 551 if (!textpos) 552 ret = -ENOMEM; 553 pr_err("Unable to mmap process text, errno %d\n", ret); 554 goto err; 555 } 556 557 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 558 len = PAGE_ALIGN(len); 559 realdatastart = vm_mmap(NULL, 0, len, 560 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 561 562 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 563 ret = realdatastart; 564 if (!realdatastart) 565 ret = -ENOMEM; 566 pr_err("Unable to allocate RAM for process data, " 567 "errno %d\n", ret); 568 vm_munmap(textpos, text_len); 569 goto err; 570 } 571 datapos = ALIGN(realdatastart + 572 MAX_SHARED_LIBS * sizeof(unsigned long), 573 FLAT_DATA_ALIGN); 574 575 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", 576 data_len + bss_len + stack_len, datapos); 577 578 fpos = ntohl(hdr->data_start); 579 #ifdef CONFIG_BINFMT_ZFLAT 580 if (flags & FLAT_FLAG_GZDATA) { 581 result = decompress_exec(bprm, fpos, (char *)datapos, 582 full_data, 0); 583 } else 584 #endif 585 { 586 result = read_code(bprm->file, datapos, fpos, 587 full_data); 588 } 589 if (IS_ERR_VALUE(result)) { 590 ret = result; 591 pr_err("Unable to read data+bss, errno %d\n", ret); 592 vm_munmap(textpos, text_len); 593 vm_munmap(realdatastart, len); 594 goto err; 595 } 596 597 reloc = (u32 __user *) 598 (datapos + (ntohl(hdr->reloc_start) - text_len)); 599 memp = realdatastart; 600 memp_size = len; 601 } else { 602 603 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32); 604 len = PAGE_ALIGN(len); 605 textpos = vm_mmap(NULL, 0, len, 606 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 607 608 if (!textpos || IS_ERR_VALUE(textpos)) { 609 ret = textpos; 610 if (!textpos) 611 ret = -ENOMEM; 612 pr_err("Unable to allocate RAM for process text/data, " 613 "errno %d\n", ret); 614 goto err; 615 } 616 617 realdatastart = textpos + ntohl(hdr->data_start); 618 datapos = ALIGN(realdatastart + 619 MAX_SHARED_LIBS * sizeof(u32), 620 FLAT_DATA_ALIGN); 621 622 reloc = (u32 __user *) 623 (datapos + (ntohl(hdr->reloc_start) - text_len)); 624 memp = textpos; 625 memp_size = len; 626 #ifdef CONFIG_BINFMT_ZFLAT 627 /* 628 * load it all in and treat it like a RAM load from now on 629 */ 630 if (flags & FLAT_FLAG_GZIP) { 631 #ifndef CONFIG_MMU 632 result = decompress_exec(bprm, sizeof(struct flat_hdr), 633 (((char *)textpos) + sizeof(struct flat_hdr)), 634 (text_len + full_data 635 - sizeof(struct flat_hdr)), 636 0); 637 memmove((void *) datapos, (void *) realdatastart, 638 full_data); 639 #else 640 /* 641 * This is used on MMU systems mainly for testing. 642 * Let's use a kernel buffer to simplify things. 643 */ 644 long unz_text_len = text_len - sizeof(struct flat_hdr); 645 long unz_len = unz_text_len + full_data; 646 char *unz_data = vmalloc(unz_len); 647 if (!unz_data) { 648 result = -ENOMEM; 649 } else { 650 result = decompress_exec(bprm, sizeof(struct flat_hdr), 651 unz_data, unz_len, 0); 652 if (result == 0 && 653 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), 654 unz_data, unz_text_len) || 655 copy_to_user((void __user *)datapos, 656 unz_data + unz_text_len, full_data))) 657 result = -EFAULT; 658 vfree(unz_data); 659 } 660 #endif 661 } else if (flags & FLAT_FLAG_GZDATA) { 662 result = read_code(bprm->file, textpos, 0, text_len); 663 if (!IS_ERR_VALUE(result)) { 664 #ifndef CONFIG_MMU 665 result = decompress_exec(bprm, text_len, (char *) datapos, 666 full_data, 0); 667 #else 668 char *unz_data = vmalloc(full_data); 669 if (!unz_data) { 670 result = -ENOMEM; 671 } else { 672 result = decompress_exec(bprm, text_len, 673 unz_data, full_data, 0); 674 if (result == 0 && 675 copy_to_user((void __user *)datapos, 676 unz_data, full_data)) 677 result = -EFAULT; 678 vfree(unz_data); 679 } 680 #endif 681 } 682 } else 683 #endif /* CONFIG_BINFMT_ZFLAT */ 684 { 685 result = read_code(bprm->file, textpos, 0, text_len); 686 if (!IS_ERR_VALUE(result)) 687 result = read_code(bprm->file, datapos, 688 ntohl(hdr->data_start), 689 full_data); 690 } 691 if (IS_ERR_VALUE(result)) { 692 ret = result; 693 pr_err("Unable to read code+data+bss, errno %d\n", ret); 694 vm_munmap(textpos, text_len + data_len + extra + 695 MAX_SHARED_LIBS * sizeof(u32)); 696 goto err; 697 } 698 } 699 700 start_code = textpos + sizeof(struct flat_hdr); 701 end_code = textpos + text_len; 702 text_len -= sizeof(struct flat_hdr); /* the real code len */ 703 704 /* The main program needs a little extra setup in the task structure */ 705 if (id == 0) { 706 current->mm->start_code = start_code; 707 current->mm->end_code = end_code; 708 current->mm->start_data = datapos; 709 current->mm->end_data = datapos + data_len; 710 /* 711 * set up the brk stuff, uses any slack left in data/bss/stack 712 * allocation. We put the brk after the bss (between the bss 713 * and stack) like other platforms. 714 * Userspace code relies on the stack pointer starting out at 715 * an address right at the end of a page. 716 */ 717 current->mm->start_brk = datapos + data_len + bss_len; 718 current->mm->brk = (current->mm->start_brk + 3) & ~3; 719 #ifndef CONFIG_MMU 720 current->mm->context.end_brk = memp + memp_size - stack_len; 721 #endif 722 } 723 724 if (flags & FLAT_FLAG_KTRACE) { 725 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", 726 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 727 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", 728 id ? "Lib" : "Load", bprm->filename, 729 start_code, end_code, datapos, datapos + data_len, 730 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); 731 } 732 733 /* Store the current module values into the global library structure */ 734 libinfo->lib_list[id].start_code = start_code; 735 libinfo->lib_list[id].start_data = datapos; 736 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 737 libinfo->lib_list[id].text_len = text_len; 738 libinfo->lib_list[id].loaded = 1; 739 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 740 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 741 742 /* 743 * We just load the allocations into some temporary memory to 744 * help simplify all this mumbo jumbo 745 * 746 * We've got two different sections of relocation entries. 747 * The first is the GOT which resides at the beginning of the data segment 748 * and is terminated with a -1. This one can be relocated in place. 749 * The second is the extra relocation entries tacked after the image's 750 * data segment. These require a little more processing as the entry is 751 * really an offset into the image which contains an offset into the 752 * image. 753 */ 754 if (flags & FLAT_FLAG_GOTPIC) { 755 for (rp = (u32 __user *)datapos; ; rp++) { 756 u32 addr, rp_val; 757 if (get_user(rp_val, rp)) 758 return -EFAULT; 759 if (rp_val == 0xffffffff) 760 break; 761 if (rp_val) { 762 addr = calc_reloc(rp_val, libinfo, id, 0); 763 if (addr == RELOC_FAILED) { 764 ret = -ENOEXEC; 765 goto err; 766 } 767 if (put_user(addr, rp)) 768 return -EFAULT; 769 } 770 } 771 } 772 773 /* 774 * Now run through the relocation entries. 775 * We've got to be careful here as C++ produces relocatable zero 776 * entries in the constructor and destructor tables which are then 777 * tested for being not zero (which will always occur unless we're 778 * based from address zero). This causes an endless loop as __start 779 * is at zero. The solution used is to not relocate zero addresses. 780 * This has the negative side effect of not allowing a global data 781 * reference to be statically initialised to _stext (I've moved 782 * __start to address 4 so that is okay). 783 */ 784 if (rev > OLD_FLAT_VERSION) { 785 u32 __maybe_unused persistent = 0; 786 for (i = 0; i < relocs; i++) { 787 u32 addr, relval; 788 789 /* 790 * Get the address of the pointer to be 791 * relocated (of course, the address has to be 792 * relocated first). 793 */ 794 if (get_user(relval, reloc + i)) 795 return -EFAULT; 796 relval = ntohl(relval); 797 if (flat_set_persistent(relval, &persistent)) 798 continue; 799 addr = flat_get_relocate_addr(relval); 800 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1); 801 if (rp == (u32 __user *)RELOC_FAILED) { 802 ret = -ENOEXEC; 803 goto err; 804 } 805 806 /* Get the pointer's value. */ 807 ret = flat_get_addr_from_rp(rp, relval, flags, 808 &addr, &persistent); 809 if (unlikely(ret)) 810 goto err; 811 812 if (addr != 0) { 813 /* 814 * Do the relocation. PIC relocs in the data section are 815 * already in target order 816 */ 817 if ((flags & FLAT_FLAG_GOTPIC) == 0) 818 addr = ntohl(addr); 819 addr = calc_reloc(addr, libinfo, id, 0); 820 if (addr == RELOC_FAILED) { 821 ret = -ENOEXEC; 822 goto err; 823 } 824 825 /* Write back the relocated pointer. */ 826 ret = flat_put_addr_at_rp(rp, addr, relval); 827 if (unlikely(ret)) 828 goto err; 829 } 830 } 831 } else { 832 for (i = 0; i < relocs; i++) { 833 u32 relval; 834 if (get_user(relval, reloc + i)) 835 return -EFAULT; 836 relval = ntohl(relval); 837 old_reloc(relval); 838 } 839 } 840 841 flush_icache_range(start_code, end_code); 842 843 /* zero the BSS, BRK and stack areas */ 844 if (clear_user((void __user *)(datapos + data_len), bss_len + 845 (memp + memp_size - stack_len - /* end brk */ 846 libinfo->lib_list[id].start_brk) + /* start brk */ 847 stack_len)) 848 return -EFAULT; 849 850 return 0; 851 err: 852 return ret; 853 } 854 855 856 /****************************************************************************/ 857 #ifdef CONFIG_BINFMT_SHARED_FLAT 858 859 /* 860 * Load a shared library into memory. The library gets its own data 861 * segment (including bss) but not argv/argc/environ. 862 */ 863 864 static int load_flat_shared_library(int id, struct lib_info *libs) 865 { 866 struct linux_binprm bprm; 867 int res; 868 char buf[16]; 869 870 memset(&bprm, 0, sizeof(bprm)); 871 872 /* Create the file name */ 873 sprintf(buf, "/lib/lib%d.so", id); 874 875 /* Open the file up */ 876 bprm.filename = buf; 877 bprm.file = open_exec(bprm.filename); 878 res = PTR_ERR(bprm.file); 879 if (IS_ERR(bprm.file)) 880 return res; 881 882 bprm.cred = prepare_exec_creds(); 883 res = -ENOMEM; 884 if (!bprm.cred) 885 goto out; 886 887 /* We don't really care about recalculating credentials at this point 888 * as we're past the point of no return and are dealing with shared 889 * libraries. 890 */ 891 bprm.called_set_creds = 1; 892 893 res = prepare_binprm(&bprm); 894 895 if (!res) 896 res = load_flat_file(&bprm, libs, id, NULL); 897 898 abort_creds(bprm.cred); 899 900 out: 901 allow_write_access(bprm.file); 902 fput(bprm.file); 903 904 return res; 905 } 906 907 #endif /* CONFIG_BINFMT_SHARED_FLAT */ 908 /****************************************************************************/ 909 910 /* 911 * These are the functions used to load flat style executables and shared 912 * libraries. There is no binary dependent code anywhere else. 913 */ 914 915 static int load_flat_binary(struct linux_binprm *bprm) 916 { 917 struct lib_info libinfo; 918 struct pt_regs *regs = current_pt_regs(); 919 unsigned long stack_len = 0; 920 unsigned long start_addr; 921 int res; 922 int i, j; 923 924 memset(&libinfo, 0, sizeof(libinfo)); 925 926 /* 927 * We have to add the size of our arguments to our stack size 928 * otherwise it's too easy for users to create stack overflows 929 * by passing in a huge argument list. And yes, we have to be 930 * pedantic and include space for the argv/envp array as it may have 931 * a lot of entries. 932 */ 933 #ifndef CONFIG_MMU 934 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ 935 #endif 936 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 937 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 938 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); 939 940 res = load_flat_file(bprm, &libinfo, 0, &stack_len); 941 if (res < 0) 942 return res; 943 944 /* Update data segment pointers for all libraries */ 945 for (i = 0; i < MAX_SHARED_LIBS; i++) { 946 if (!libinfo.lib_list[i].loaded) 947 continue; 948 for (j = 0; j < MAX_SHARED_LIBS; j++) { 949 unsigned long val = libinfo.lib_list[j].loaded ? 950 libinfo.lib_list[j].start_data : UNLOADED_LIB; 951 unsigned long __user *p = (unsigned long __user *) 952 libinfo.lib_list[i].start_data; 953 p -= j + 1; 954 if (put_user(val, p)) 955 return -EFAULT; 956 } 957 } 958 959 install_exec_creds(bprm); 960 961 set_binfmt(&flat_format); 962 963 #ifdef CONFIG_MMU 964 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); 965 if (!res) 966 res = create_flat_tables(bprm, bprm->p); 967 #else 968 /* Stash our initial stack pointer into the mm structure */ 969 current->mm->start_stack = 970 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 971 pr_debug("sp=%lx\n", current->mm->start_stack); 972 973 /* copy the arg pages onto the stack */ 974 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack); 975 if (!res) 976 res = create_flat_tables(bprm, current->mm->start_stack); 977 #endif 978 if (res) 979 return res; 980 981 /* Fake some return addresses to ensure the call chain will 982 * initialise library in order for us. We are required to call 983 * lib 1 first, then 2, ... and finally the main program (id 0). 984 */ 985 start_addr = libinfo.lib_list[0].entry; 986 987 #ifdef CONFIG_BINFMT_SHARED_FLAT 988 for (i = MAX_SHARED_LIBS-1; i > 0; i--) { 989 if (libinfo.lib_list[i].loaded) { 990 /* Push previos first to call address */ 991 unsigned long __user *sp; 992 current->mm->start_stack -= sizeof(unsigned long); 993 sp = (unsigned long __user *)current->mm->start_stack; 994 __put_user(start_addr, sp); 995 start_addr = libinfo.lib_list[i].entry; 996 } 997 } 998 #endif 999 1000 #ifdef FLAT_PLAT_INIT 1001 FLAT_PLAT_INIT(regs); 1002 #endif 1003 1004 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", 1005 regs, start_addr, current->mm->start_stack); 1006 start_thread(regs, start_addr, current->mm->start_stack); 1007 1008 return 0; 1009 } 1010 1011 /****************************************************************************/ 1012 1013 static int __init init_flat_binfmt(void) 1014 { 1015 register_binfmt(&flat_format); 1016 return 0; 1017 } 1018 core_initcall(init_flat_binfmt); 1019 1020 /****************************************************************************/ 1021