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 == NULL) { 196 pr_debug("no memory for decompress workspace\n"); 197 return -ENOMEM; 198 } 199 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 200 if (buf == NULL) { 201 pr_debug("no memory for read buffer\n"); 202 retval = -ENOMEM; 203 goto out_free; 204 } 205 206 /* Read in first chunk of data and parse gzip header. */ 207 fpos = offset; 208 ret = kernel_read(bprm->file, offset, buf, LBUFSIZE); 209 210 strm.next_in = buf; 211 strm.avail_in = ret; 212 strm.total_in = 0; 213 fpos += ret; 214 215 retval = -ENOEXEC; 216 217 /* Check minimum size -- gzip header */ 218 if (ret < 10) { 219 pr_debug("file too small?\n"); 220 goto out_free_buf; 221 } 222 223 /* Check gzip magic number */ 224 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 225 pr_debug("unknown compression magic?\n"); 226 goto out_free_buf; 227 } 228 229 /* Check gzip method */ 230 if (buf[2] != 8) { 231 pr_debug("unknown compression method?\n"); 232 goto out_free_buf; 233 } 234 /* Check gzip flags */ 235 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 236 (buf[3] & RESERVED)) { 237 pr_debug("unknown flags?\n"); 238 goto out_free_buf; 239 } 240 241 ret = 10; 242 if (buf[3] & EXTRA_FIELD) { 243 ret += 2 + buf[10] + (buf[11] << 8); 244 if (unlikely(ret >= LBUFSIZE)) { 245 pr_debug("buffer overflow (EXTRA)?\n"); 246 goto out_free_buf; 247 } 248 } 249 if (buf[3] & ORIG_NAME) { 250 while (ret < LBUFSIZE && buf[ret++] != 0) 251 ; 252 if (unlikely(ret == LBUFSIZE)) { 253 pr_debug("buffer overflow (ORIG_NAME)?\n"); 254 goto out_free_buf; 255 } 256 } 257 if (buf[3] & COMMENT) { 258 while (ret < LBUFSIZE && buf[ret++] != 0) 259 ; 260 if (unlikely(ret == LBUFSIZE)) { 261 pr_debug("buffer overflow (COMMENT)?\n"); 262 goto out_free_buf; 263 } 264 } 265 266 strm.next_in += ret; 267 strm.avail_in -= ret; 268 269 strm.next_out = dst; 270 strm.avail_out = len; 271 strm.total_out = 0; 272 273 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 274 pr_debug("zlib init failed?\n"); 275 goto out_free_buf; 276 } 277 278 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 279 ret = kernel_read(bprm->file, fpos, buf, LBUFSIZE); 280 if (ret <= 0) 281 break; 282 len -= ret; 283 284 strm.next_in = buf; 285 strm.avail_in = ret; 286 strm.total_in = 0; 287 fpos += ret; 288 } 289 290 if (ret < 0) { 291 pr_debug("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 pr_err("reference 0x%lx to shared library %d", r, id); 329 goto failed; 330 } 331 if (curid != id) { 332 if (internalp) { 333 pr_err("reloc address 0x%lx not in same module " 334 "(%d != %d)", r, curid, id); 335 goto failed; 336 } else if (!p->lib_list[id].loaded && 337 load_flat_shared_library(id, p) < 0) { 338 pr_err("failed to load library %d", id); 339 goto failed; 340 } 341 /* Check versioning information (i.e. time stamps) */ 342 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 343 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 344 pr_err("library %d is younger than %d", id, curid); 345 goto failed; 346 } 347 } 348 #else 349 id = 0; 350 #endif 351 352 start_brk = p->lib_list[id].start_brk; 353 start_data = p->lib_list[id].start_data; 354 start_code = p->lib_list[id].start_code; 355 text_len = p->lib_list[id].text_len; 356 357 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { 358 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", 359 r, start_brk-start_data+text_len, text_len); 360 goto failed; 361 } 362 363 if (r < text_len) /* In text segment */ 364 addr = r + start_code; 365 else /* In data segment */ 366 addr = r - text_len + start_data; 367 368 /* Range checked already above so doing the range tests is redundant...*/ 369 return addr; 370 371 failed: 372 pr_cont(", killing %s!\n", current->comm); 373 send_sig(SIGSEGV, current, 0); 374 375 return RELOC_FAILED; 376 } 377 378 /****************************************************************************/ 379 380 static void old_reloc(unsigned long rl) 381 { 382 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 383 flat_v2_reloc_t r; 384 unsigned long __user *ptr; 385 unsigned long val; 386 387 r.value = rl; 388 #if defined(CONFIG_COLDFIRE) 389 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); 390 #else 391 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); 392 #endif 393 get_user(val, ptr); 394 395 pr_debug("Relocation of variable at DATASEG+%x " 396 "(address %p, currently %lx) into segment %s\n", 397 r.reloc.offset, ptr, val, segment[r.reloc.type]); 398 399 switch (r.reloc.type) { 400 case OLD_FLAT_RELOC_TYPE_TEXT: 401 val += current->mm->start_code; 402 break; 403 case OLD_FLAT_RELOC_TYPE_DATA: 404 val += current->mm->start_data; 405 break; 406 case OLD_FLAT_RELOC_TYPE_BSS: 407 val += current->mm->end_data; 408 break; 409 default: 410 pr_err("Unknown relocation type=%x\n", r.reloc.type); 411 break; 412 } 413 put_user(val, ptr); 414 415 pr_debug("Relocation became %lx\n", val); 416 } 417 418 /****************************************************************************/ 419 420 static int load_flat_file(struct linux_binprm *bprm, 421 struct lib_info *libinfo, int id, unsigned long *extra_stack) 422 { 423 struct flat_hdr *hdr; 424 unsigned long textpos, datapos, realdatastart; 425 u32 text_len, data_len, bss_len, stack_len, full_data, flags; 426 unsigned long len, memp, memp_size, extra, rlim; 427 u32 __user *reloc, *rp; 428 struct inode *inode; 429 int i, rev, relocs; 430 loff_t fpos; 431 unsigned long start_code, end_code; 432 ssize_t result; 433 int ret; 434 435 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 436 inode = file_inode(bprm->file); 437 438 text_len = ntohl(hdr->data_start); 439 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 440 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 441 stack_len = ntohl(hdr->stack_size); 442 if (extra_stack) { 443 stack_len += *extra_stack; 444 *extra_stack = stack_len; 445 } 446 relocs = ntohl(hdr->reloc_count); 447 flags = ntohl(hdr->flags); 448 rev = ntohl(hdr->rev); 449 full_data = data_len + relocs * sizeof(unsigned long); 450 451 if (strncmp(hdr->magic, "bFLT", 4)) { 452 /* 453 * Previously, here was a printk to tell people 454 * "BINFMT_FLAT: bad header magic". 455 * But for the kernel which also use ELF FD-PIC format, this 456 * error message is confusing. 457 * because a lot of people do not manage to produce good 458 */ 459 ret = -ENOEXEC; 460 goto err; 461 } 462 463 if (flags & FLAT_FLAG_KTRACE) 464 pr_info("Loading file: %s\n", bprm->filename); 465 466 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 467 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", 468 rev, FLAT_VERSION, OLD_FLAT_VERSION); 469 ret = -ENOEXEC; 470 goto err; 471 } 472 473 /* Don't allow old format executables to use shared libraries */ 474 if (rev == OLD_FLAT_VERSION && id != 0) { 475 pr_err("shared libraries are not available before rev 0x%lx\n", 476 FLAT_VERSION); 477 ret = -ENOEXEC; 478 goto err; 479 } 480 481 /* 482 * Make sure the header params are sane. 483 * 28 bits (256 MB) is way more than reasonable in this case. 484 * If some top bits are set we have probable binary corruption. 485 */ 486 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { 487 pr_err("bad header\n"); 488 ret = -ENOEXEC; 489 goto err; 490 } 491 492 /* 493 * fix up the flags for the older format, there were all kinds 494 * of endian hacks, this only works for the simple cases 495 */ 496 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) 497 flags = FLAT_FLAG_RAM; 498 499 #ifndef CONFIG_BINFMT_ZFLAT 500 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 501 pr_err("Support for ZFLAT executables is not enabled.\n"); 502 ret = -ENOEXEC; 503 goto err; 504 } 505 #endif 506 507 /* 508 * Check initial limits. This avoids letting people circumvent 509 * size limits imposed on them by creating programs with large 510 * arrays in the data or bss. 511 */ 512 rlim = rlimit(RLIMIT_DATA); 513 if (rlim >= RLIM_INFINITY) 514 rlim = ~0; 515 if (data_len + bss_len > rlim) { 516 ret = -ENOMEM; 517 goto err; 518 } 519 520 /* Flush all traces of the currently running executable */ 521 if (id == 0) { 522 ret = flush_old_exec(bprm); 523 if (ret) 524 goto err; 525 526 /* OK, This is the point of no return */ 527 set_personality(PER_LINUX_32BIT); 528 setup_new_exec(bprm); 529 } 530 531 /* 532 * calculate the extra space we need to map in 533 */ 534 extra = max_t(unsigned long, bss_len + stack_len, 535 relocs * sizeof(unsigned long)); 536 537 /* 538 * there are a couple of cases here, the separate code/data 539 * case, and then the fully copied to RAM case which lumps 540 * it all together. 541 */ 542 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { 543 /* 544 * this should give us a ROM ptr, but if it doesn't we don't 545 * really care 546 */ 547 pr_debug("ROM mapping of file (we hope)\n"); 548 549 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 550 MAP_PRIVATE|MAP_EXECUTABLE, 0); 551 if (!textpos || IS_ERR_VALUE(textpos)) { 552 ret = textpos; 553 if (!textpos) 554 ret = -ENOMEM; 555 pr_err("Unable to mmap process text, errno %d\n", ret); 556 goto err; 557 } 558 559 len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); 560 len = PAGE_ALIGN(len); 561 realdatastart = vm_mmap(NULL, 0, len, 562 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 563 564 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 565 ret = realdatastart; 566 if (!realdatastart) 567 ret = -ENOMEM; 568 pr_err("Unable to allocate RAM for process data, " 569 "errno %d\n", ret); 570 vm_munmap(textpos, text_len); 571 goto err; 572 } 573 datapos = ALIGN(realdatastart + 574 MAX_SHARED_LIBS * sizeof(unsigned long), 575 FLAT_DATA_ALIGN); 576 577 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", 578 data_len + bss_len + stack_len, datapos); 579 580 fpos = ntohl(hdr->data_start); 581 #ifdef CONFIG_BINFMT_ZFLAT 582 if (flags & FLAT_FLAG_GZDATA) { 583 result = decompress_exec(bprm, fpos, (char *)datapos, 584 full_data, 0); 585 } else 586 #endif 587 { 588 result = read_code(bprm->file, datapos, fpos, 589 full_data); 590 } 591 if (IS_ERR_VALUE(result)) { 592 ret = result; 593 pr_err("Unable to read data+bss, errno %d\n", ret); 594 vm_munmap(textpos, text_len); 595 vm_munmap(realdatastart, len); 596 goto err; 597 } 598 599 reloc = (u32 __user *) 600 (datapos + (ntohl(hdr->reloc_start) - text_len)); 601 memp = realdatastart; 602 memp_size = len; 603 } else { 604 605 len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32); 606 len = PAGE_ALIGN(len); 607 textpos = vm_mmap(NULL, 0, len, 608 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 609 610 if (!textpos || IS_ERR_VALUE(textpos)) { 611 ret = textpos; 612 if (!textpos) 613 ret = -ENOMEM; 614 pr_err("Unable to allocate RAM for process text/data, " 615 "errno %d\n", ret); 616 goto err; 617 } 618 619 realdatastart = textpos + ntohl(hdr->data_start); 620 datapos = ALIGN(realdatastart + 621 MAX_SHARED_LIBS * sizeof(u32), 622 FLAT_DATA_ALIGN); 623 624 reloc = (u32 __user *) 625 (datapos + (ntohl(hdr->reloc_start) - text_len)); 626 memp = textpos; 627 memp_size = len; 628 #ifdef CONFIG_BINFMT_ZFLAT 629 /* 630 * load it all in and treat it like a RAM load from now on 631 */ 632 if (flags & FLAT_FLAG_GZIP) { 633 #ifndef CONFIG_MMU 634 result = decompress_exec(bprm, sizeof(struct flat_hdr), 635 (((char *)textpos) + sizeof(struct flat_hdr)), 636 (text_len + full_data 637 - sizeof(struct flat_hdr)), 638 0); 639 memmove((void *) datapos, (void *) realdatastart, 640 full_data); 641 #else 642 /* 643 * This is used on MMU systems mainly for testing. 644 * Let's use a kernel buffer to simplify things. 645 */ 646 long unz_text_len = text_len - sizeof(struct flat_hdr); 647 long unz_len = unz_text_len + full_data; 648 char *unz_data = vmalloc(unz_len); 649 if (!unz_data) { 650 result = -ENOMEM; 651 } else { 652 result = decompress_exec(bprm, sizeof(struct flat_hdr), 653 unz_data, unz_len, 0); 654 if (result == 0 && 655 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), 656 unz_data, unz_text_len) || 657 copy_to_user((void __user *)datapos, 658 unz_data + unz_text_len, full_data))) 659 result = -EFAULT; 660 vfree(unz_data); 661 } 662 #endif 663 } else if (flags & FLAT_FLAG_GZDATA) { 664 result = read_code(bprm->file, textpos, 0, text_len); 665 if (!IS_ERR_VALUE(result)) { 666 #ifndef CONFIG_MMU 667 result = decompress_exec(bprm, text_len, (char *) datapos, 668 full_data, 0); 669 #else 670 char *unz_data = vmalloc(full_data); 671 if (!unz_data) { 672 result = -ENOMEM; 673 } else { 674 result = decompress_exec(bprm, text_len, 675 unz_data, full_data, 0); 676 if (result == 0 && 677 copy_to_user((void __user *)datapos, 678 unz_data, full_data)) 679 result = -EFAULT; 680 vfree(unz_data); 681 } 682 #endif 683 } 684 } else 685 #endif /* CONFIG_BINFMT_ZFLAT */ 686 { 687 result = read_code(bprm->file, textpos, 0, text_len); 688 if (!IS_ERR_VALUE(result)) 689 result = read_code(bprm->file, datapos, 690 ntohl(hdr->data_start), 691 full_data); 692 } 693 if (IS_ERR_VALUE(result)) { 694 ret = result; 695 pr_err("Unable to read code+data+bss, errno %d\n", ret); 696 vm_munmap(textpos, text_len + data_len + extra + 697 MAX_SHARED_LIBS * sizeof(u32)); 698 goto err; 699 } 700 } 701 702 start_code = textpos + sizeof(struct flat_hdr); 703 end_code = textpos + text_len; 704 text_len -= sizeof(struct flat_hdr); /* the real code len */ 705 706 /* The main program needs a little extra setup in the task structure */ 707 if (id == 0) { 708 current->mm->start_code = start_code; 709 current->mm->end_code = end_code; 710 current->mm->start_data = datapos; 711 current->mm->end_data = datapos + data_len; 712 /* 713 * set up the brk stuff, uses any slack left in data/bss/stack 714 * allocation. We put the brk after the bss (between the bss 715 * and stack) like other platforms. 716 * Userspace code relies on the stack pointer starting out at 717 * an address right at the end of a page. 718 */ 719 current->mm->start_brk = datapos + data_len + bss_len; 720 current->mm->brk = (current->mm->start_brk + 3) & ~3; 721 #ifndef CONFIG_MMU 722 current->mm->context.end_brk = memp + memp_size - stack_len; 723 #endif 724 } 725 726 if (flags & FLAT_FLAG_KTRACE) { 727 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", 728 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 729 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", 730 id ? "Lib" : "Load", bprm->filename, 731 start_code, end_code, datapos, datapos + data_len, 732 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); 733 } 734 735 /* Store the current module values into the global library structure */ 736 libinfo->lib_list[id].start_code = start_code; 737 libinfo->lib_list[id].start_data = datapos; 738 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 739 libinfo->lib_list[id].text_len = text_len; 740 libinfo->lib_list[id].loaded = 1; 741 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 742 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 743 744 /* 745 * We just load the allocations into some temporary memory to 746 * help simplify all this mumbo jumbo 747 * 748 * We've got two different sections of relocation entries. 749 * The first is the GOT which resides at the beginning of the data segment 750 * and is terminated with a -1. This one can be relocated in place. 751 * The second is the extra relocation entries tacked after the image's 752 * data segment. These require a little more processing as the entry is 753 * really an offset into the image which contains an offset into the 754 * image. 755 */ 756 if (flags & FLAT_FLAG_GOTPIC) { 757 for (rp = (u32 __user *)datapos; ; rp++) { 758 u32 addr, rp_val; 759 if (get_user(rp_val, rp)) 760 return -EFAULT; 761 if (rp_val == 0xffffffff) 762 break; 763 if (rp_val) { 764 addr = calc_reloc(rp_val, libinfo, id, 0); 765 if (addr == RELOC_FAILED) { 766 ret = -ENOEXEC; 767 goto err; 768 } 769 if (put_user(addr, rp)) 770 return -EFAULT; 771 } 772 } 773 } 774 775 /* 776 * Now run through the relocation entries. 777 * We've got to be careful here as C++ produces relocatable zero 778 * entries in the constructor and destructor tables which are then 779 * tested for being not zero (which will always occur unless we're 780 * based from address zero). This causes an endless loop as __start 781 * is at zero. The solution used is to not relocate zero addresses. 782 * This has the negative side effect of not allowing a global data 783 * reference to be statically initialised to _stext (I've moved 784 * __start to address 4 so that is okay). 785 */ 786 if (rev > OLD_FLAT_VERSION) { 787 u32 __maybe_unused persistent = 0; 788 for (i = 0; i < relocs; i++) { 789 u32 addr, relval; 790 791 /* 792 * Get the address of the pointer to be 793 * relocated (of course, the address has to be 794 * relocated first). 795 */ 796 if (get_user(relval, reloc + i)) 797 return -EFAULT; 798 relval = ntohl(relval); 799 if (flat_set_persistent(relval, &persistent)) 800 continue; 801 addr = flat_get_relocate_addr(relval); 802 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1); 803 if (rp == (u32 __user *)RELOC_FAILED) { 804 ret = -ENOEXEC; 805 goto err; 806 } 807 808 /* Get the pointer's value. */ 809 ret = flat_get_addr_from_rp(rp, relval, flags, 810 &addr, &persistent); 811 if (unlikely(ret)) 812 goto err; 813 814 if (addr != 0) { 815 /* 816 * Do the relocation. PIC relocs in the data section are 817 * already in target order 818 */ 819 if ((flags & FLAT_FLAG_GOTPIC) == 0) 820 addr = ntohl(addr); 821 addr = calc_reloc(addr, libinfo, id, 0); 822 if (addr == RELOC_FAILED) { 823 ret = -ENOEXEC; 824 goto err; 825 } 826 827 /* Write back the relocated pointer. */ 828 ret = flat_put_addr_at_rp(rp, addr, relval); 829 if (unlikely(ret)) 830 goto err; 831 } 832 } 833 } else { 834 for (i = 0; i < relocs; i++) { 835 u32 relval; 836 if (get_user(relval, reloc + i)) 837 return -EFAULT; 838 relval = ntohl(relval); 839 old_reloc(relval); 840 } 841 } 842 843 flush_icache_range(start_code, end_code); 844 845 /* zero the BSS, BRK and stack areas */ 846 if (clear_user((void __user *)(datapos + data_len), bss_len + 847 (memp + memp_size - stack_len - /* end brk */ 848 libinfo->lib_list[id].start_brk) + /* start brk */ 849 stack_len)) 850 return -EFAULT; 851 852 return 0; 853 err: 854 return ret; 855 } 856 857 858 /****************************************************************************/ 859 #ifdef CONFIG_BINFMT_SHARED_FLAT 860 861 /* 862 * Load a shared library into memory. The library gets its own data 863 * segment (including bss) but not argv/argc/environ. 864 */ 865 866 static int load_flat_shared_library(int id, struct lib_info *libs) 867 { 868 struct linux_binprm bprm; 869 int res; 870 char buf[16]; 871 872 memset(&bprm, 0, sizeof(bprm)); 873 874 /* Create the file name */ 875 sprintf(buf, "/lib/lib%d.so", id); 876 877 /* Open the file up */ 878 bprm.filename = buf; 879 bprm.file = open_exec(bprm.filename); 880 res = PTR_ERR(bprm.file); 881 if (IS_ERR(bprm.file)) 882 return res; 883 884 bprm.cred = prepare_exec_creds(); 885 res = -ENOMEM; 886 if (!bprm.cred) 887 goto out; 888 889 /* We don't really care about recalculating credentials at this point 890 * as we're past the point of no return and are dealing with shared 891 * libraries. 892 */ 893 bprm.cred_prepared = 1; 894 895 res = prepare_binprm(&bprm); 896 897 if (!res) 898 res = load_flat_file(&bprm, libs, id, NULL); 899 900 abort_creds(bprm.cred); 901 902 out: 903 allow_write_access(bprm.file); 904 fput(bprm.file); 905 906 return res; 907 } 908 909 #endif /* CONFIG_BINFMT_SHARED_FLAT */ 910 /****************************************************************************/ 911 912 /* 913 * These are the functions used to load flat style executables and shared 914 * libraries. There is no binary dependent code anywhere else. 915 */ 916 917 static int load_flat_binary(struct linux_binprm *bprm) 918 { 919 struct lib_info libinfo; 920 struct pt_regs *regs = current_pt_regs(); 921 unsigned long stack_len = 0; 922 unsigned long start_addr; 923 int res; 924 int i, j; 925 926 memset(&libinfo, 0, sizeof(libinfo)); 927 928 /* 929 * We have to add the size of our arguments to our stack size 930 * otherwise it's too easy for users to create stack overflows 931 * by passing in a huge argument list. And yes, we have to be 932 * pedantic and include space for the argv/envp array as it may have 933 * a lot of entries. 934 */ 935 #ifndef CONFIG_MMU 936 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ 937 #endif 938 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 939 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 940 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); 941 942 res = load_flat_file(bprm, &libinfo, 0, &stack_len); 943 if (res < 0) 944 return res; 945 946 /* Update data segment pointers for all libraries */ 947 for (i = 0; i < MAX_SHARED_LIBS; i++) { 948 if (!libinfo.lib_list[i].loaded) 949 continue; 950 for (j = 0; j < MAX_SHARED_LIBS; j++) { 951 unsigned long val = libinfo.lib_list[j].loaded ? 952 libinfo.lib_list[j].start_data : UNLOADED_LIB; 953 unsigned long __user *p = (unsigned long __user *) 954 libinfo.lib_list[i].start_data; 955 p -= j + 1; 956 if (put_user(val, p)) 957 return -EFAULT; 958 } 959 } 960 961 install_exec_creds(bprm); 962 963 set_binfmt(&flat_format); 964 965 #ifdef CONFIG_MMU 966 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); 967 if (!res) 968 res = create_flat_tables(bprm, bprm->p); 969 #else 970 /* Stash our initial stack pointer into the mm structure */ 971 current->mm->start_stack = 972 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 973 pr_debug("sp=%lx\n", current->mm->start_stack); 974 975 /* copy the arg pages onto the stack */ 976 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack); 977 if (!res) 978 res = create_flat_tables(bprm, current->mm->start_stack); 979 #endif 980 if (res) 981 return res; 982 983 /* Fake some return addresses to ensure the call chain will 984 * initialise library in order for us. We are required to call 985 * lib 1 first, then 2, ... and finally the main program (id 0). 986 */ 987 start_addr = libinfo.lib_list[0].entry; 988 989 #ifdef CONFIG_BINFMT_SHARED_FLAT 990 for (i = MAX_SHARED_LIBS-1; i > 0; i--) { 991 if (libinfo.lib_list[i].loaded) { 992 /* Push previos first to call address */ 993 unsigned long __user *sp; 994 current->mm->start_stack -= sizeof(unsigned long); 995 sp = (unsigned long __user *)current->mm->start_stack; 996 __put_user(start_addr, sp); 997 start_addr = libinfo.lib_list[i].entry; 998 } 999 } 1000 #endif 1001 1002 #ifdef FLAT_PLAT_INIT 1003 FLAT_PLAT_INIT(regs); 1004 #endif 1005 1006 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", 1007 regs, start_addr, current->mm->start_stack); 1008 start_thread(regs, start_addr, current->mm->start_stack); 1009 1010 return 0; 1011 } 1012 1013 /****************************************************************************/ 1014 1015 static int __init init_flat_binfmt(void) 1016 { 1017 register_binfmt(&flat_format); 1018 return 0; 1019 } 1020 core_initcall(init_flat_binfmt); 1021 1022 /****************************************************************************/ 1023