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/mm.h> 23 #include <linux/mman.h> 24 #include <linux/errno.h> 25 #include <linux/signal.h> 26 #include <linux/string.h> 27 #include <linux/fs.h> 28 #include <linux/file.h> 29 #include <linux/ptrace.h> 30 #include <linux/user.h> 31 #include <linux/slab.h> 32 #include <linux/binfmts.h> 33 #include <linux/personality.h> 34 #include <linux/init.h> 35 #include <linux/flat.h> 36 #include <linux/uaccess.h> 37 #include <linux/vmalloc.h> 38 39 #include <asm/byteorder.h> 40 #include <asm/unaligned.h> 41 #include <asm/cacheflush.h> 42 #include <asm/page.h> 43 44 /****************************************************************************/ 45 46 /* 47 * User data (data section and bss) needs to be aligned. 48 * We pick 0x20 here because it is the max value elf2flt has always 49 * used in producing FLAT files, and because it seems to be large 50 * enough to make all the gcc alignment related tests happy. 51 */ 52 #define FLAT_DATA_ALIGN (0x20) 53 54 /* 55 * User data (stack) also needs to be aligned. 56 * Here we can be a bit looser than the data sections since this 57 * needs to only meet arch ABI requirements. 58 */ 59 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) 60 61 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ 62 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ 63 64 struct lib_info { 65 struct { 66 unsigned long start_code; /* Start of text segment */ 67 unsigned long start_data; /* Start of data segment */ 68 unsigned long start_brk; /* End of data segment */ 69 unsigned long text_len; /* Length of text segment */ 70 unsigned long entry; /* Start address for this module */ 71 unsigned long build_date; /* When this one was compiled */ 72 bool loaded; /* Has this library been loaded? */ 73 } lib_list[MAX_SHARED_LIBS]; 74 }; 75 76 #ifdef CONFIG_BINFMT_SHARED_FLAT 77 static int load_flat_shared_library(int id, struct lib_info *p); 78 #endif 79 80 static int load_flat_binary(struct linux_binprm *); 81 static int flat_core_dump(struct coredump_params *cprm); 82 83 static struct linux_binfmt flat_format = { 84 .module = THIS_MODULE, 85 .load_binary = load_flat_binary, 86 .core_dump = flat_core_dump, 87 .min_coredump = PAGE_SIZE 88 }; 89 90 /****************************************************************************/ 91 /* 92 * Routine writes a core dump image in the current directory. 93 * Currently only a stub-function. 94 */ 95 96 static int flat_core_dump(struct coredump_params *cprm) 97 { 98 pr_warn("Process %s:%d received signr %d and should have core dumped\n", 99 current->comm, current->pid, cprm->siginfo->si_signo); 100 return 1; 101 } 102 103 /****************************************************************************/ 104 /* 105 * create_flat_tables() parses the env- and arg-strings in new user 106 * memory and creates the pointer tables from them, and puts their 107 * addresses on the "stack", recording the new stack pointer value. 108 */ 109 110 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start) 111 { 112 char __user *p; 113 unsigned long __user *sp; 114 long i, len; 115 116 p = (char __user *)arg_start; 117 sp = (unsigned long __user *)current->mm->start_stack; 118 119 sp -= bprm->envc + 1; 120 sp -= bprm->argc + 1; 121 sp -= flat_argvp_envp_on_stack() ? 2 : 0; 122 sp -= 1; /* &argc */ 123 124 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN; 125 sp = (unsigned long __user *)current->mm->start_stack; 126 127 __put_user(bprm->argc, sp++); 128 if (flat_argvp_envp_on_stack()) { 129 unsigned long argv, envp; 130 argv = (unsigned long)(sp + 2); 131 envp = (unsigned long)(sp + 2 + bprm->argc + 1); 132 __put_user(argv, sp++); 133 __put_user(envp, sp++); 134 } 135 136 current->mm->arg_start = (unsigned long)p; 137 for (i = bprm->argc; i > 0; i--) { 138 __put_user((unsigned long)p, sp++); 139 len = strnlen_user(p, MAX_ARG_STRLEN); 140 if (!len || len > MAX_ARG_STRLEN) 141 return -EINVAL; 142 p += len; 143 } 144 __put_user(0, sp++); 145 current->mm->arg_end = (unsigned long)p; 146 147 current->mm->env_start = (unsigned long) p; 148 for (i = bprm->envc; i > 0; i--) { 149 __put_user((unsigned long)p, sp++); 150 len = strnlen_user(p, MAX_ARG_STRLEN); 151 if (!len || len > MAX_ARG_STRLEN) 152 return -EINVAL; 153 p += len; 154 } 155 __put_user(0, sp++); 156 current->mm->env_end = (unsigned long)p; 157 158 return 0; 159 } 160 161 /****************************************************************************/ 162 163 #ifdef CONFIG_BINFMT_ZFLAT 164 165 #include <linux/zlib.h> 166 167 #define LBUFSIZE 4000 168 169 /* gzip flag byte */ 170 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 171 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 172 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 173 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 174 #define COMMENT 0x10 /* bit 4 set: file comment present */ 175 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 176 #define RESERVED 0xC0 /* bit 6,7: reserved */ 177 178 static int decompress_exec( 179 struct linux_binprm *bprm, 180 unsigned long offset, 181 char *dst, 182 long len, 183 int fd) 184 { 185 unsigned char *buf; 186 z_stream strm; 187 loff_t fpos; 188 int ret, retval; 189 190 pr_debug("decompress_exec(offset=%lx,buf=%p,len=%lx)\n", offset, dst, len); 191 192 memset(&strm, 0, sizeof(strm)); 193 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); 194 if (strm.workspace == NULL) { 195 pr_debug("no memory for decompress workspace\n"); 196 return -ENOMEM; 197 } 198 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 199 if (buf == NULL) { 200 pr_debug("no memory for read buffer\n"); 201 retval = -ENOMEM; 202 goto out_free; 203 } 204 205 /* Read in first chunk of data and parse gzip header. */ 206 fpos = offset; 207 ret = kernel_read(bprm->file, offset, buf, LBUFSIZE); 208 209 strm.next_in = buf; 210 strm.avail_in = ret; 211 strm.total_in = 0; 212 fpos += ret; 213 214 retval = -ENOEXEC; 215 216 /* Check minimum size -- gzip header */ 217 if (ret < 10) { 218 pr_debug("file too small?\n"); 219 goto out_free_buf; 220 } 221 222 /* Check gzip magic number */ 223 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 224 pr_debug("unknown compression magic?\n"); 225 goto out_free_buf; 226 } 227 228 /* Check gzip method */ 229 if (buf[2] != 8) { 230 pr_debug("unknown compression method?\n"); 231 goto out_free_buf; 232 } 233 /* Check gzip flags */ 234 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 235 (buf[3] & RESERVED)) { 236 pr_debug("unknown flags?\n"); 237 goto out_free_buf; 238 } 239 240 ret = 10; 241 if (buf[3] & EXTRA_FIELD) { 242 ret += 2 + buf[10] + (buf[11] << 8); 243 if (unlikely(ret >= LBUFSIZE)) { 244 pr_debug("buffer overflow (EXTRA)?\n"); 245 goto out_free_buf; 246 } 247 } 248 if (buf[3] & ORIG_NAME) { 249 while (ret < LBUFSIZE && buf[ret++] != 0) 250 ; 251 if (unlikely(ret == LBUFSIZE)) { 252 pr_debug("buffer overflow (ORIG_NAME)?\n"); 253 goto out_free_buf; 254 } 255 } 256 if (buf[3] & COMMENT) { 257 while (ret < LBUFSIZE && buf[ret++] != 0) 258 ; 259 if (unlikely(ret == LBUFSIZE)) { 260 pr_debug("buffer overflow (COMMENT)?\n"); 261 goto out_free_buf; 262 } 263 } 264 265 strm.next_in += ret; 266 strm.avail_in -= ret; 267 268 strm.next_out = dst; 269 strm.avail_out = len; 270 strm.total_out = 0; 271 272 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 273 pr_debug("zlib init failed?\n"); 274 goto out_free_buf; 275 } 276 277 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 278 ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE); 279 if (ret <= 0) 280 break; 281 len -= ret; 282 283 strm.next_in = buf; 284 strm.avail_in = ret; 285 strm.total_in = 0; 286 fpos += ret; 287 } 288 289 if (ret < 0) { 290 pr_debug("decompression failed (%d), %s\n", 291 ret, strm.msg); 292 goto out_zlib; 293 } 294 295 retval = 0; 296 out_zlib: 297 zlib_inflateEnd(&strm); 298 out_free_buf: 299 kfree(buf); 300 out_free: 301 kfree(strm.workspace); 302 return retval; 303 } 304 305 #endif /* CONFIG_BINFMT_ZFLAT */ 306 307 /****************************************************************************/ 308 309 static unsigned long 310 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) 311 { 312 unsigned long addr; 313 int id; 314 unsigned long start_brk; 315 unsigned long start_data; 316 unsigned long text_len; 317 unsigned long start_code; 318 319 #ifdef CONFIG_BINFMT_SHARED_FLAT 320 if (r == 0) 321 id = curid; /* Relocs of 0 are always self referring */ 322 else { 323 id = (r >> 24) & 0xff; /* Find ID for this reloc */ 324 r &= 0x00ffffff; /* Trim ID off here */ 325 } 326 if (id >= MAX_SHARED_LIBS) { 327 pr_err("reference 0x%lx to shared library %d", r, id); 328 goto failed; 329 } 330 if (curid != id) { 331 if (internalp) { 332 pr_err("reloc address 0x%lx not in same module " 333 "(%d != %d)", r, curid, id); 334 goto failed; 335 } else if (!p->lib_list[id].loaded && 336 load_flat_shared_library(id, p) < 0) { 337 pr_err("failed to load library %d", id); 338 goto failed; 339 } 340 /* Check versioning information (i.e. time stamps) */ 341 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 342 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 343 pr_err("library %d is younger than %d", id, curid); 344 goto failed; 345 } 346 } 347 #else 348 id = 0; 349 #endif 350 351 start_brk = p->lib_list[id].start_brk; 352 start_data = p->lib_list[id].start_data; 353 start_code = p->lib_list[id].start_code; 354 text_len = p->lib_list[id].text_len; 355 356 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { 357 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", 358 r, start_brk-start_data+text_len, text_len); 359 goto failed; 360 } 361 362 if (r < text_len) /* In text segment */ 363 addr = r + start_code; 364 else /* In data segment */ 365 addr = r - text_len + start_data; 366 367 /* Range checked already above so doing the range tests is redundant...*/ 368 return addr; 369 370 failed: 371 pr_cont(", killing %s!\n", current->comm); 372 send_sig(SIGSEGV, current, 0); 373 374 return RELOC_FAILED; 375 } 376 377 /****************************************************************************/ 378 379 static void old_reloc(unsigned long rl) 380 { 381 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 382 flat_v2_reloc_t r; 383 unsigned long __user *ptr; 384 unsigned long val; 385 386 r.value = rl; 387 #if defined(CONFIG_COLDFIRE) 388 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); 389 #else 390 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); 391 #endif 392 get_user(val, ptr); 393 394 pr_debug("Relocation of variable at DATASEG+%x " 395 "(address %p, currently %lx) into segment %s\n", 396 r.reloc.offset, ptr, val, segment[r.reloc.type]); 397 398 switch (r.reloc.type) { 399 case OLD_FLAT_RELOC_TYPE_TEXT: 400 val += current->mm->start_code; 401 break; 402 case OLD_FLAT_RELOC_TYPE_DATA: 403 val += current->mm->start_data; 404 break; 405 case OLD_FLAT_RELOC_TYPE_BSS: 406 val += current->mm->end_data; 407 break; 408 default: 409 pr_err("Unknown relocation type=%x\n", r.reloc.type); 410 break; 411 } 412 put_user(val, ptr); 413 414 pr_debug("Relocation became %lx\n", val); 415 } 416 417 /****************************************************************************/ 418 419 static int load_flat_file(struct linux_binprm *bprm, 420 struct lib_info *libinfo, int id, unsigned long *extra_stack) 421 { 422 struct flat_hdr *hdr; 423 unsigned long textpos, datapos, realdatastart; 424 unsigned long text_len, data_len, bss_len, stack_len, full_data, flags; 425 unsigned long len, memp, memp_size, extra, rlim; 426 unsigned long __user *reloc, *rp; 427 struct inode *inode; 428 int i, rev, relocs; 429 loff_t fpos; 430 unsigned long start_code, end_code; 431 ssize_t result; 432 int ret; 433 434 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 435 inode = file_inode(bprm->file); 436 437 text_len = ntohl(hdr->data_start); 438 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 439 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 440 stack_len = ntohl(hdr->stack_size); 441 if (extra_stack) { 442 stack_len += *extra_stack; 443 *extra_stack = stack_len; 444 } 445 relocs = ntohl(hdr->reloc_count); 446 flags = ntohl(hdr->flags); 447 rev = ntohl(hdr->rev); 448 full_data = data_len + relocs * sizeof(unsigned long); 449 450 if (strncmp(hdr->magic, "bFLT", 4)) { 451 /* 452 * Previously, here was a printk to tell people 453 * "BINFMT_FLAT: bad header magic". 454 * But for the kernel which also use ELF FD-PIC format, this 455 * error message is confusing. 456 * because a lot of people do not manage to produce good 457 */ 458 ret = -ENOEXEC; 459 goto err; 460 } 461 462 if (flags & FLAT_FLAG_KTRACE) 463 pr_info("Loading file: %s\n", bprm->filename); 464 465 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 466 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", 467 rev, FLAT_VERSION, OLD_FLAT_VERSION); 468 ret = -ENOEXEC; 469 goto err; 470 } 471 472 /* Don't allow old format executables to use shared libraries */ 473 if (rev == OLD_FLAT_VERSION && id != 0) { 474 pr_err("shared libraries are not available before rev 0x%lx\n", 475 FLAT_VERSION); 476 ret = -ENOEXEC; 477 goto err; 478 } 479 480 /* 481 * Make sure the header params are sane. 482 * 28 bits (256 MB) is way more than reasonable in this case. 483 * If some top bits are set we have probable binary corruption. 484 */ 485 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { 486 pr_err("bad header\n"); 487 ret = -ENOEXEC; 488 goto err; 489 } 490 491 /* 492 * fix up the flags for the older format, there were all kinds 493 * of endian hacks, this only works for the simple cases 494 */ 495 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) 496 flags = FLAT_FLAG_RAM; 497 498 #ifndef CONFIG_BINFMT_ZFLAT 499 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 500 pr_err("Support for ZFLAT executables is not enabled.\n"); 501 ret = -ENOEXEC; 502 goto err; 503 } 504 #endif 505 506 /* 507 * Check initial limits. This avoids letting people circumvent 508 * size limits imposed on them by creating programs with large 509 * arrays in the data or bss. 510 */ 511 rlim = rlimit(RLIMIT_DATA); 512 if (rlim >= RLIM_INFINITY) 513 rlim = ~0; 514 if (data_len + bss_len > rlim) { 515 ret = -ENOMEM; 516 goto err; 517 } 518 519 /* Flush all traces of the currently running executable */ 520 if (id == 0) { 521 ret = flush_old_exec(bprm); 522 if (ret) 523 goto err; 524 525 /* OK, This is the point of no return */ 526 set_personality(PER_LINUX_32BIT); 527 setup_new_exec(bprm); 528 } 529 530 /* 531 * calculate the extra space we need to map in 532 */ 533 extra = max_t(unsigned long, bss_len + stack_len, 534 relocs * sizeof(unsigned long)); 535 536 /* 537 * there are a couple of cases here, the separate code/data 538 * case, and then the fully copied to RAM case which lumps 539 * it all together. 540 */ 541 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { 542 /* 543 * this should give us a ROM ptr, but if it doesn't we don't 544 * really care 545 */ 546 pr_debug("ROM mapping of file (we hope)\n"); 547 548 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 549 MAP_PRIVATE|MAP_EXECUTABLE, 0); 550 if (!textpos || IS_ERR_VALUE(textpos)) { 551 ret = textpos; 552 if (!textpos) 553 ret = -ENOMEM; 554 pr_err("Unable to mmap process text, errno %d\n", ret); 555 goto err; 556 } 557 558 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 559 len = PAGE_ALIGN(len); 560 realdatastart = vm_mmap(NULL, 0, len, 561 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 562 563 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 564 ret = realdatastart; 565 if (!realdatastart) 566 ret = -ENOMEM; 567 pr_err("Unable to allocate RAM for process data, " 568 "errno %d\n", ret); 569 vm_munmap(textpos, text_len); 570 goto err; 571 } 572 datapos = ALIGN(realdatastart + 573 MAX_SHARED_LIBS * sizeof(unsigned long), 574 FLAT_DATA_ALIGN); 575 576 pr_debug("Allocated data+bss+stack (%ld bytes): %lx\n", 577 data_len + bss_len + stack_len, datapos); 578 579 fpos = ntohl(hdr->data_start); 580 #ifdef CONFIG_BINFMT_ZFLAT 581 if (flags & FLAT_FLAG_GZDATA) { 582 result = decompress_exec(bprm, fpos, (char *)datapos, 583 full_data, 0); 584 } else 585 #endif 586 { 587 result = read_code(bprm->file, datapos, fpos, 588 full_data); 589 } 590 if (IS_ERR_VALUE(result)) { 591 ret = result; 592 pr_err("Unable to read data+bss, errno %d\n", ret); 593 vm_munmap(textpos, text_len); 594 vm_munmap(realdatastart, len); 595 goto err; 596 } 597 598 reloc = (unsigned long __user *) 599 (datapos + (ntohl(hdr->reloc_start) - text_len)); 600 memp = realdatastart; 601 memp_size = len; 602 } else { 603 604 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 605 len = PAGE_ALIGN(len); 606 textpos = vm_mmap(NULL, 0, len, 607 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 608 609 if (!textpos || IS_ERR_VALUE(textpos)) { 610 ret = textpos; 611 if (!textpos) 612 ret = -ENOMEM; 613 pr_err("Unable to allocate RAM for process text/data, " 614 "errno %d\n", ret); 615 goto err; 616 } 617 618 realdatastart = textpos + ntohl(hdr->data_start); 619 datapos = ALIGN(realdatastart + 620 MAX_SHARED_LIBS * sizeof(unsigned long), 621 FLAT_DATA_ALIGN); 622 623 reloc = (unsigned long __user *) 624 (datapos + (ntohl(hdr->reloc_start) - text_len)); 625 memp = textpos; 626 memp_size = len; 627 #ifdef CONFIG_BINFMT_ZFLAT 628 /* 629 * load it all in and treat it like a RAM load from now on 630 */ 631 if (flags & FLAT_FLAG_GZIP) { 632 #ifndef CONFIG_MMU 633 result = decompress_exec(bprm, sizeof(struct flat_hdr), 634 (((char *)textpos) + sizeof(struct flat_hdr)), 635 (text_len + full_data 636 - sizeof(struct flat_hdr)), 637 0); 638 memmove((void *) datapos, (void *) realdatastart, 639 full_data); 640 #else 641 /* 642 * This is used on MMU systems mainly for testing. 643 * Let's use a kernel buffer to simplify things. 644 */ 645 long unz_text_len = text_len - sizeof(struct flat_hdr); 646 long unz_len = unz_text_len + full_data; 647 char *unz_data = vmalloc(unz_len); 648 if (!unz_data) { 649 result = -ENOMEM; 650 } else { 651 result = decompress_exec(bprm, sizeof(struct flat_hdr), 652 unz_data, unz_len, 0); 653 if (result == 0 && 654 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), 655 unz_data, unz_text_len) || 656 copy_to_user((void __user *)datapos, 657 unz_data + unz_text_len, full_data))) 658 result = -EFAULT; 659 vfree(unz_data); 660 } 661 #endif 662 } else if (flags & FLAT_FLAG_GZDATA) { 663 result = read_code(bprm->file, textpos, 0, text_len); 664 if (!IS_ERR_VALUE(result)) { 665 #ifndef CONFIG_MMU 666 result = decompress_exec(bprm, text_len, (char *) datapos, 667 full_data, 0); 668 #else 669 char *unz_data = vmalloc(full_data); 670 if (!unz_data) { 671 result = -ENOMEM; 672 } else { 673 result = decompress_exec(bprm, text_len, 674 unz_data, full_data, 0); 675 if (result == 0 && 676 copy_to_user((void __user *)datapos, 677 unz_data, full_data)) 678 result = -EFAULT; 679 vfree(unz_data); 680 } 681 #endif 682 } 683 } else 684 #endif /* CONFIG_BINFMT_ZFLAT */ 685 { 686 result = read_code(bprm->file, textpos, 0, text_len); 687 if (!IS_ERR_VALUE(result)) 688 result = read_code(bprm->file, datapos, 689 ntohl(hdr->data_start), 690 full_data); 691 } 692 if (IS_ERR_VALUE(result)) { 693 ret = result; 694 pr_err("Unable to read code+data+bss, errno %d\n", ret); 695 vm_munmap(textpos, text_len + data_len + extra + 696 MAX_SHARED_LIBS * sizeof(unsigned long)); 697 goto err; 698 } 699 } 700 701 start_code = textpos + sizeof(struct flat_hdr); 702 end_code = textpos + text_len; 703 text_len -= sizeof(struct flat_hdr); /* the real code len */ 704 705 /* The main program needs a little extra setup in the task structure */ 706 if (id == 0) { 707 current->mm->start_code = start_code; 708 current->mm->end_code = end_code; 709 current->mm->start_data = datapos; 710 current->mm->end_data = datapos + data_len; 711 /* 712 * set up the brk stuff, uses any slack left in data/bss/stack 713 * allocation. We put the brk after the bss (between the bss 714 * and stack) like other platforms. 715 * Userspace code relies on the stack pointer starting out at 716 * an address right at the end of a page. 717 */ 718 current->mm->start_brk = datapos + data_len + bss_len; 719 current->mm->brk = (current->mm->start_brk + 3) & ~3; 720 #ifndef CONFIG_MMU 721 current->mm->context.end_brk = memp + memp_size - stack_len; 722 #endif 723 } 724 725 if (flags & FLAT_FLAG_KTRACE) { 726 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", 727 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 728 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", 729 id ? "Lib" : "Load", bprm->filename, 730 start_code, end_code, datapos, datapos + data_len, 731 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); 732 } 733 734 /* Store the current module values into the global library structure */ 735 libinfo->lib_list[id].start_code = start_code; 736 libinfo->lib_list[id].start_data = datapos; 737 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 738 libinfo->lib_list[id].text_len = text_len; 739 libinfo->lib_list[id].loaded = 1; 740 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 741 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 742 743 /* 744 * We just load the allocations into some temporary memory to 745 * help simplify all this mumbo jumbo 746 * 747 * We've got two different sections of relocation entries. 748 * The first is the GOT which resides at the beginning of the data segment 749 * and is terminated with a -1. This one can be relocated in place. 750 * The second is the extra relocation entries tacked after the image's 751 * data segment. These require a little more processing as the entry is 752 * really an offset into the image which contains an offset into the 753 * image. 754 */ 755 if (flags & FLAT_FLAG_GOTPIC) { 756 for (rp = (unsigned long __user *)datapos; ; rp++) { 757 unsigned long addr, rp_val; 758 if (get_user(rp_val, rp)) 759 return -EFAULT; 760 if (rp_val == 0xffffffff) 761 break; 762 if (rp_val) { 763 addr = calc_reloc(rp_val, libinfo, id, 0); 764 if (addr == RELOC_FAILED) { 765 ret = -ENOEXEC; 766 goto err; 767 } 768 if (put_user(addr, rp)) 769 return -EFAULT; 770 } 771 } 772 } 773 774 /* 775 * Now run through the relocation entries. 776 * We've got to be careful here as C++ produces relocatable zero 777 * entries in the constructor and destructor tables which are then 778 * tested for being not zero (which will always occur unless we're 779 * based from address zero). This causes an endless loop as __start 780 * is at zero. The solution used is to not relocate zero addresses. 781 * This has the negative side effect of not allowing a global data 782 * reference to be statically initialised to _stext (I've moved 783 * __start to address 4 so that is okay). 784 */ 785 if (rev > OLD_FLAT_VERSION) { 786 unsigned long __maybe_unused persistent = 0; 787 for (i = 0; i < relocs; i++) { 788 unsigned long addr, relval; 789 790 /* 791 * Get the address of the pointer to be 792 * relocated (of course, the address has to be 793 * relocated first). 794 */ 795 if (get_user(relval, reloc + i)) 796 return -EFAULT; 797 relval = ntohl(relval); 798 if (flat_set_persistent(relval, &persistent)) 799 continue; 800 addr = flat_get_relocate_addr(relval); 801 rp = (unsigned long __user *)calc_reloc(addr, libinfo, id, 1); 802 if (rp == (unsigned long __user *)RELOC_FAILED) { 803 ret = -ENOEXEC; 804 goto err; 805 } 806 807 /* Get the pointer's value. */ 808 addr = flat_get_addr_from_rp(rp, relval, flags, 809 &persistent); 810 if (addr != 0) { 811 /* 812 * Do the relocation. PIC relocs in the data section are 813 * already in target order 814 */ 815 if ((flags & FLAT_FLAG_GOTPIC) == 0) 816 addr = ntohl(addr); 817 addr = calc_reloc(addr, libinfo, id, 0); 818 if (addr == RELOC_FAILED) { 819 ret = -ENOEXEC; 820 goto err; 821 } 822 823 /* Write back the relocated pointer. */ 824 flat_put_addr_at_rp(rp, addr, relval); 825 } 826 } 827 } else { 828 for (i = 0; i < relocs; i++) { 829 unsigned long relval; 830 if (get_user(relval, reloc + i)) 831 return -EFAULT; 832 relval = ntohl(relval); 833 old_reloc(relval); 834 } 835 } 836 837 flush_icache_range(start_code, end_code); 838 839 /* zero the BSS, BRK and stack areas */ 840 if (clear_user((void __user *)(datapos + data_len), bss_len + 841 (memp + memp_size - stack_len - /* end brk */ 842 libinfo->lib_list[id].start_brk) + /* start brk */ 843 stack_len)) 844 return -EFAULT; 845 846 return 0; 847 err: 848 return ret; 849 } 850 851 852 /****************************************************************************/ 853 #ifdef CONFIG_BINFMT_SHARED_FLAT 854 855 /* 856 * Load a shared library into memory. The library gets its own data 857 * segment (including bss) but not argv/argc/environ. 858 */ 859 860 static int load_flat_shared_library(int id, struct lib_info *libs) 861 { 862 struct linux_binprm bprm; 863 int res; 864 char buf[16]; 865 866 memset(&bprm, 0, sizeof(bprm)); 867 868 /* Create the file name */ 869 sprintf(buf, "/lib/lib%d.so", id); 870 871 /* Open the file up */ 872 bprm.filename = buf; 873 bprm.file = open_exec(bprm.filename); 874 res = PTR_ERR(bprm.file); 875 if (IS_ERR(bprm.file)) 876 return res; 877 878 bprm.cred = prepare_exec_creds(); 879 res = -ENOMEM; 880 if (!bprm.cred) 881 goto out; 882 883 /* We don't really care about recalculating credentials at this point 884 * as we're past the point of no return and are dealing with shared 885 * libraries. 886 */ 887 bprm.cred_prepared = 1; 888 889 res = prepare_binprm(&bprm); 890 891 if (!res) 892 res = load_flat_file(&bprm, libs, id, NULL); 893 894 abort_creds(bprm.cred); 895 896 out: 897 allow_write_access(bprm.file); 898 fput(bprm.file); 899 900 return res; 901 } 902 903 #endif /* CONFIG_BINFMT_SHARED_FLAT */ 904 /****************************************************************************/ 905 906 /* 907 * These are the functions used to load flat style executables and shared 908 * libraries. There is no binary dependent code anywhere else. 909 */ 910 911 static int load_flat_binary(struct linux_binprm *bprm) 912 { 913 struct lib_info libinfo; 914 struct pt_regs *regs = current_pt_regs(); 915 unsigned long stack_len = 0; 916 unsigned long start_addr; 917 int res; 918 int i, j; 919 920 memset(&libinfo, 0, sizeof(libinfo)); 921 922 /* 923 * We have to add the size of our arguments to our stack size 924 * otherwise it's too easy for users to create stack overflows 925 * by passing in a huge argument list. And yes, we have to be 926 * pedantic and include space for the argv/envp array as it may have 927 * a lot of entries. 928 */ 929 #ifndef CONFIG_MMU 930 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ 931 #endif 932 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 933 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 934 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); 935 936 res = load_flat_file(bprm, &libinfo, 0, &stack_len); 937 if (res < 0) 938 return res; 939 940 /* Update data segment pointers for all libraries */ 941 for (i = 0; i < MAX_SHARED_LIBS; i++) { 942 if (!libinfo.lib_list[i].loaded) 943 continue; 944 for (j = 0; j < MAX_SHARED_LIBS; j++) { 945 unsigned long val = libinfo.lib_list[j].loaded ? 946 libinfo.lib_list[j].start_data : UNLOADED_LIB; 947 unsigned long __user *p = (unsigned long __user *) 948 libinfo.lib_list[i].start_data; 949 p -= j + 1; 950 if (put_user(val, p)) 951 return -EFAULT; 952 } 953 } 954 955 install_exec_creds(bprm); 956 957 set_binfmt(&flat_format); 958 959 #ifdef CONFIG_MMU 960 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); 961 if (!res) 962 res = create_flat_tables(bprm, bprm->p); 963 #else 964 /* Stash our initial stack pointer into the mm structure */ 965 current->mm->start_stack = 966 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 967 pr_debug("sp=%lx\n", current->mm->start_stack); 968 969 /* copy the arg pages onto the stack */ 970 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack); 971 if (!res) 972 res = create_flat_tables(bprm, current->mm->start_stack); 973 #endif 974 if (res) 975 return res; 976 977 /* Fake some return addresses to ensure the call chain will 978 * initialise library in order for us. We are required to call 979 * lib 1 first, then 2, ... and finally the main program (id 0). 980 */ 981 start_addr = libinfo.lib_list[0].entry; 982 983 #ifdef CONFIG_BINFMT_SHARED_FLAT 984 for (i = MAX_SHARED_LIBS-1; i > 0; i--) { 985 if (libinfo.lib_list[i].loaded) { 986 /* Push previos first to call address */ 987 unsigned long __user *sp; 988 current->mm->start_stack -= sizeof(unsigned long); 989 sp = (unsigned long __user *)current->mm->start_stack; 990 __put_user(start_addr, sp); 991 start_addr = libinfo.lib_list[i].entry; 992 } 993 } 994 #endif 995 996 #ifdef FLAT_PLAT_INIT 997 FLAT_PLAT_INIT(regs); 998 #endif 999 1000 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", 1001 regs, start_addr, current->mm->start_stack); 1002 start_thread(regs, start_addr, current->mm->start_stack); 1003 1004 return 0; 1005 } 1006 1007 /****************************************************************************/ 1008 1009 static int __init init_flat_binfmt(void) 1010 { 1011 register_binfmt(&flat_format); 1012 return 0; 1013 } 1014 core_initcall(init_flat_binfmt); 1015 1016 /****************************************************************************/ 1017