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