1 // SPDX-License-Identifier: GPL-2.0 2 /****************************************************************************/ 3 /* 4 * linux/fs/binfmt_flat.c 5 * 6 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com> 7 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com> 8 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com> 9 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com> 10 * based heavily on: 11 * 12 * linux/fs/binfmt_aout.c: 13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds 14 * linux/fs/binfmt_flat.c for 2.0 kernel 15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com> 16 * JAN/99 -- coded full program relocation (gerg@snapgear.com) 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/kernel.h> 22 #include <linux/sched.h> 23 #include <linux/sched/task_stack.h> 24 #include <linux/mm.h> 25 #include <linux/mman.h> 26 #include <linux/errno.h> 27 #include <linux/signal.h> 28 #include <linux/string.h> 29 #include <linux/fs.h> 30 #include <linux/file.h> 31 #include <linux/ptrace.h> 32 #include <linux/user.h> 33 #include <linux/slab.h> 34 #include <linux/binfmts.h> 35 #include <linux/personality.h> 36 #include <linux/init.h> 37 #include <linux/flat.h> 38 #include <linux/uaccess.h> 39 #include <linux/vmalloc.h> 40 41 #include <asm/byteorder.h> 42 #include <asm/unaligned.h> 43 #include <asm/cacheflush.h> 44 #include <asm/page.h> 45 #include <asm/flat.h> 46 47 #ifndef flat_get_relocate_addr 48 #define flat_get_relocate_addr(rel) (rel) 49 #endif 50 51 /****************************************************************************/ 52 53 /* 54 * User data (data section and bss) needs to be aligned. 55 * We pick 0x20 here because it is the max value elf2flt has always 56 * used in producing FLAT files, and because it seems to be large 57 * enough to make all the gcc alignment related tests happy. 58 */ 59 #define FLAT_DATA_ALIGN (0x20) 60 61 /* 62 * User data (stack) also needs to be aligned. 63 * Here we can be a bit looser than the data sections since this 64 * needs to only meet arch ABI requirements. 65 */ 66 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) 67 68 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ 69 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ 70 71 #ifdef CONFIG_BINFMT_SHARED_FLAT 72 #define MAX_SHARED_LIBS (4) 73 #else 74 #define MAX_SHARED_LIBS (1) 75 #endif 76 77 struct lib_info { 78 struct { 79 unsigned long start_code; /* Start of text segment */ 80 unsigned long start_data; /* Start of data segment */ 81 unsigned long start_brk; /* End of data segment */ 82 unsigned long text_len; /* Length of text segment */ 83 unsigned long entry; /* Start address for this module */ 84 unsigned long build_date; /* When this one was compiled */ 85 bool loaded; /* Has this library been loaded? */ 86 } lib_list[MAX_SHARED_LIBS]; 87 }; 88 89 #ifdef CONFIG_BINFMT_SHARED_FLAT 90 static int load_flat_shared_library(int id, struct lib_info *p); 91 #endif 92 93 static int load_flat_binary(struct linux_binprm *); 94 static int flat_core_dump(struct coredump_params *cprm); 95 96 static struct linux_binfmt flat_format = { 97 .module = THIS_MODULE, 98 .load_binary = load_flat_binary, 99 .core_dump = flat_core_dump, 100 .min_coredump = PAGE_SIZE 101 }; 102 103 /****************************************************************************/ 104 /* 105 * Routine writes a core dump image in the current directory. 106 * Currently only a stub-function. 107 */ 108 109 static int flat_core_dump(struct coredump_params *cprm) 110 { 111 pr_warn("Process %s:%d received signr %d and should have core dumped\n", 112 current->comm, current->pid, cprm->siginfo->si_signo); 113 return 1; 114 } 115 116 /****************************************************************************/ 117 /* 118 * create_flat_tables() parses the env- and arg-strings in new user 119 * memory and creates the pointer tables from them, and puts their 120 * addresses on the "stack", recording the new stack pointer value. 121 */ 122 123 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start) 124 { 125 char __user *p; 126 unsigned long __user *sp; 127 long i, len; 128 129 p = (char __user *)arg_start; 130 sp = (unsigned long __user *)current->mm->start_stack; 131 132 sp -= bprm->envc + 1; 133 sp -= bprm->argc + 1; 134 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) 135 sp -= 2; /* argvp + envp */ 136 sp -= 1; /* &argc */ 137 138 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN; 139 sp = (unsigned long __user *)current->mm->start_stack; 140 141 __put_user(bprm->argc, sp++); 142 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) { 143 unsigned long argv, envp; 144 argv = (unsigned long)(sp + 2); 145 envp = (unsigned long)(sp + 2 + bprm->argc + 1); 146 __put_user(argv, sp++); 147 __put_user(envp, sp++); 148 } 149 150 current->mm->arg_start = (unsigned long)p; 151 for (i = bprm->argc; i > 0; i--) { 152 __put_user((unsigned long)p, sp++); 153 len = strnlen_user(p, MAX_ARG_STRLEN); 154 if (!len || len > MAX_ARG_STRLEN) 155 return -EINVAL; 156 p += len; 157 } 158 __put_user(0, sp++); 159 current->mm->arg_end = (unsigned long)p; 160 161 current->mm->env_start = (unsigned long) p; 162 for (i = bprm->envc; i > 0; i--) { 163 __put_user((unsigned long)p, sp++); 164 len = strnlen_user(p, MAX_ARG_STRLEN); 165 if (!len || len > MAX_ARG_STRLEN) 166 return -EINVAL; 167 p += len; 168 } 169 __put_user(0, sp++); 170 current->mm->env_end = (unsigned long)p; 171 172 return 0; 173 } 174 175 /****************************************************************************/ 176 177 #ifdef CONFIG_BINFMT_ZFLAT 178 179 #include <linux/zlib.h> 180 181 #define LBUFSIZE 4000 182 183 /* gzip flag byte */ 184 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 185 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 186 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 187 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 188 #define COMMENT 0x10 /* bit 4 set: file comment present */ 189 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 190 #define RESERVED 0xC0 /* bit 6,7: reserved */ 191 192 static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst, 193 long len, int fd) 194 { 195 unsigned char *buf; 196 z_stream strm; 197 int ret, retval; 198 199 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len); 200 201 memset(&strm, 0, sizeof(strm)); 202 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); 203 if (!strm.workspace) 204 return -ENOMEM; 205 206 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 207 if (!buf) { 208 retval = -ENOMEM; 209 goto out_free; 210 } 211 212 /* Read in first chunk of data and parse gzip header. */ 213 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); 214 215 strm.next_in = buf; 216 strm.avail_in = ret; 217 strm.total_in = 0; 218 219 retval = -ENOEXEC; 220 221 /* Check minimum size -- gzip header */ 222 if (ret < 10) { 223 pr_debug("file too small?\n"); 224 goto out_free_buf; 225 } 226 227 /* Check gzip magic number */ 228 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 229 pr_debug("unknown compression magic?\n"); 230 goto out_free_buf; 231 } 232 233 /* Check gzip method */ 234 if (buf[2] != 8) { 235 pr_debug("unknown compression method?\n"); 236 goto out_free_buf; 237 } 238 /* Check gzip flags */ 239 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 240 (buf[3] & RESERVED)) { 241 pr_debug("unknown flags?\n"); 242 goto out_free_buf; 243 } 244 245 ret = 10; 246 if (buf[3] & EXTRA_FIELD) { 247 ret += 2 + buf[10] + (buf[11] << 8); 248 if (unlikely(ret >= LBUFSIZE)) { 249 pr_debug("buffer overflow (EXTRA)?\n"); 250 goto out_free_buf; 251 } 252 } 253 if (buf[3] & ORIG_NAME) { 254 while (ret < LBUFSIZE && buf[ret++] != 0) 255 ; 256 if (unlikely(ret == LBUFSIZE)) { 257 pr_debug("buffer overflow (ORIG_NAME)?\n"); 258 goto out_free_buf; 259 } 260 } 261 if (buf[3] & COMMENT) { 262 while (ret < LBUFSIZE && buf[ret++] != 0) 263 ; 264 if (unlikely(ret == LBUFSIZE)) { 265 pr_debug("buffer overflow (COMMENT)?\n"); 266 goto out_free_buf; 267 } 268 } 269 270 strm.next_in += ret; 271 strm.avail_in -= ret; 272 273 strm.next_out = dst; 274 strm.avail_out = len; 275 strm.total_out = 0; 276 277 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 278 pr_debug("zlib init failed?\n"); 279 goto out_free_buf; 280 } 281 282 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 283 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); 284 if (ret <= 0) 285 break; 286 len -= ret; 287 288 strm.next_in = buf; 289 strm.avail_in = ret; 290 strm.total_in = 0; 291 } 292 293 if (ret < 0) { 294 pr_debug("decompression failed (%d), %s\n", 295 ret, strm.msg); 296 goto out_zlib; 297 } 298 299 retval = 0; 300 out_zlib: 301 zlib_inflateEnd(&strm); 302 out_free_buf: 303 kfree(buf); 304 out_free: 305 kfree(strm.workspace); 306 return retval; 307 } 308 309 #endif /* CONFIG_BINFMT_ZFLAT */ 310 311 /****************************************************************************/ 312 313 static unsigned long 314 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) 315 { 316 unsigned long addr; 317 int id; 318 unsigned long start_brk; 319 unsigned long start_data; 320 unsigned long text_len; 321 unsigned long start_code; 322 323 #ifdef CONFIG_BINFMT_SHARED_FLAT 324 if (r == 0) 325 id = curid; /* Relocs of 0 are always self referring */ 326 else { 327 id = (r >> 24) & 0xff; /* Find ID for this reloc */ 328 r &= 0x00ffffff; /* Trim ID off here */ 329 } 330 if (id >= MAX_SHARED_LIBS) { 331 pr_err("reference 0x%lx to shared library %d", r, id); 332 goto failed; 333 } 334 if (curid != id) { 335 if (internalp) { 336 pr_err("reloc address 0x%lx not in same module " 337 "(%d != %d)", r, curid, id); 338 goto failed; 339 } else if (!p->lib_list[id].loaded && 340 load_flat_shared_library(id, p) < 0) { 341 pr_err("failed to load library %d", id); 342 goto failed; 343 } 344 /* Check versioning information (i.e. time stamps) */ 345 if (p->lib_list[id].build_date && p->lib_list[curid].build_date && 346 p->lib_list[curid].build_date < p->lib_list[id].build_date) { 347 pr_err("library %d is younger than %d", id, curid); 348 goto failed; 349 } 350 } 351 #else 352 id = 0; 353 #endif 354 355 start_brk = p->lib_list[id].start_brk; 356 start_data = p->lib_list[id].start_data; 357 start_code = p->lib_list[id].start_code; 358 text_len = p->lib_list[id].text_len; 359 360 if (r > start_brk - start_data + text_len) { 361 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", 362 r, start_brk-start_data+text_len, text_len); 363 goto failed; 364 } 365 366 if (r < text_len) /* In text segment */ 367 addr = r + start_code; 368 else /* In data segment */ 369 addr = r - text_len + start_data; 370 371 /* Range checked already above so doing the range tests is redundant...*/ 372 return addr; 373 374 failed: 375 pr_cont(", killing %s!\n", current->comm); 376 send_sig(SIGSEGV, current, 0); 377 378 return RELOC_FAILED; 379 } 380 381 /****************************************************************************/ 382 383 #ifdef CONFIG_BINFMT_FLAT_OLD 384 static void old_reloc(unsigned long rl) 385 { 386 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 387 flat_v2_reloc_t r; 388 unsigned long __user *ptr; 389 unsigned long val; 390 391 r.value = rl; 392 #if defined(CONFIG_COLDFIRE) 393 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); 394 #else 395 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); 396 #endif 397 get_user(val, ptr); 398 399 pr_debug("Relocation of variable at DATASEG+%x " 400 "(address %p, currently %lx) into segment %s\n", 401 r.reloc.offset, ptr, val, segment[r.reloc.type]); 402 403 switch (r.reloc.type) { 404 case OLD_FLAT_RELOC_TYPE_TEXT: 405 val += current->mm->start_code; 406 break; 407 case OLD_FLAT_RELOC_TYPE_DATA: 408 val += current->mm->start_data; 409 break; 410 case OLD_FLAT_RELOC_TYPE_BSS: 411 val += current->mm->end_data; 412 break; 413 default: 414 pr_err("Unknown relocation type=%x\n", r.reloc.type); 415 break; 416 } 417 put_user(val, ptr); 418 419 pr_debug("Relocation became %lx\n", val); 420 } 421 #endif /* CONFIG_BINFMT_FLAT_OLD */ 422 423 /****************************************************************************/ 424 425 static int load_flat_file(struct linux_binprm *bprm, 426 struct lib_info *libinfo, int id, unsigned long *extra_stack) 427 { 428 struct flat_hdr *hdr; 429 unsigned long textpos, datapos, realdatastart; 430 u32 text_len, data_len, bss_len, stack_len, full_data, flags; 431 unsigned long len, memp, memp_size, extra, rlim; 432 __be32 __user *reloc; 433 u32 __user *rp; 434 struct inode *inode; 435 int i, rev, relocs; 436 loff_t fpos; 437 unsigned long start_code, end_code; 438 ssize_t result; 439 int ret; 440 441 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 442 inode = file_inode(bprm->file); 443 444 text_len = ntohl(hdr->data_start); 445 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 446 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 447 stack_len = ntohl(hdr->stack_size); 448 if (extra_stack) { 449 stack_len += *extra_stack; 450 *extra_stack = stack_len; 451 } 452 relocs = ntohl(hdr->reloc_count); 453 flags = ntohl(hdr->flags); 454 rev = ntohl(hdr->rev); 455 full_data = data_len + relocs * sizeof(unsigned long); 456 457 if (strncmp(hdr->magic, "bFLT", 4)) { 458 /* 459 * Previously, here was a printk to tell people 460 * "BINFMT_FLAT: bad header magic". 461 * But for the kernel which also use ELF FD-PIC format, this 462 * error message is confusing. 463 * because a lot of people do not manage to produce good 464 */ 465 ret = -ENOEXEC; 466 goto err; 467 } 468 469 if (flags & FLAT_FLAG_KTRACE) 470 pr_info("Loading file: %s\n", bprm->filename); 471 472 #ifdef CONFIG_BINFMT_FLAT_OLD 473 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 474 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", 475 rev, FLAT_VERSION, OLD_FLAT_VERSION); 476 ret = -ENOEXEC; 477 goto err; 478 } 479 480 /* Don't allow old format executables to use shared libraries */ 481 if (rev == OLD_FLAT_VERSION && id != 0) { 482 pr_err("shared libraries are not available before rev 0x%lx\n", 483 FLAT_VERSION); 484 ret = -ENOEXEC; 485 goto err; 486 } 487 488 /* 489 * fix up the flags for the older format, there were all kinds 490 * of endian hacks, this only works for the simple cases 491 */ 492 if (rev == OLD_FLAT_VERSION && 493 (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM))) 494 flags = FLAT_FLAG_RAM; 495 496 #else /* CONFIG_BINFMT_FLAT_OLD */ 497 if (rev != FLAT_VERSION) { 498 pr_err("bad flat file version 0x%x (supported 0x%lx)\n", 499 rev, FLAT_VERSION); 500 ret = -ENOEXEC; 501 goto err; 502 } 503 #endif /* !CONFIG_BINFMT_FLAT_OLD */ 504 505 /* 506 * Make sure the header params are sane. 507 * 28 bits (256 MB) is way more than reasonable in this case. 508 * If some top bits are set we have probable binary corruption. 509 */ 510 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { 511 pr_err("bad header\n"); 512 ret = -ENOEXEC; 513 goto err; 514 } 515 516 #ifndef CONFIG_BINFMT_ZFLAT 517 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 518 pr_err("Support for ZFLAT executables is not enabled.\n"); 519 ret = -ENOEXEC; 520 goto err; 521 } 522 #endif 523 524 /* 525 * Check initial limits. This avoids letting people circumvent 526 * size limits imposed on them by creating programs with large 527 * arrays in the data or bss. 528 */ 529 rlim = rlimit(RLIMIT_DATA); 530 if (rlim >= RLIM_INFINITY) 531 rlim = ~0; 532 if (data_len + bss_len > rlim) { 533 ret = -ENOMEM; 534 goto err; 535 } 536 537 /* Flush all traces of the currently running executable */ 538 if (id == 0) { 539 ret = flush_old_exec(bprm); 540 if (ret) 541 goto err; 542 543 /* OK, This is the point of no return */ 544 set_personality(PER_LINUX_32BIT); 545 setup_new_exec(bprm); 546 } 547 548 /* 549 * calculate the extra space we need to map in 550 */ 551 extra = max_t(unsigned long, bss_len + stack_len, 552 relocs * sizeof(unsigned long)); 553 554 /* 555 * there are a couple of cases here, the separate code/data 556 * case, and then the fully copied to RAM case which lumps 557 * it all together. 558 */ 559 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { 560 /* 561 * this should give us a ROM ptr, but if it doesn't we don't 562 * really care 563 */ 564 pr_debug("ROM mapping of file (we hope)\n"); 565 566 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 567 MAP_PRIVATE|MAP_EXECUTABLE, 0); 568 if (!textpos || IS_ERR_VALUE(textpos)) { 569 ret = textpos; 570 if (!textpos) 571 ret = -ENOMEM; 572 pr_err("Unable to mmap process text, errno %d\n", ret); 573 goto err; 574 } 575 576 len = data_len + extra; 577 len = PAGE_ALIGN(len); 578 realdatastart = vm_mmap(NULL, 0, len, 579 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 580 581 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 582 ret = realdatastart; 583 if (!realdatastart) 584 ret = -ENOMEM; 585 pr_err("Unable to allocate RAM for process data, " 586 "errno %d\n", ret); 587 vm_munmap(textpos, text_len); 588 goto err; 589 } 590 datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN); 591 592 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", 593 data_len + bss_len + stack_len, datapos); 594 595 fpos = ntohl(hdr->data_start); 596 #ifdef CONFIG_BINFMT_ZFLAT 597 if (flags & FLAT_FLAG_GZDATA) { 598 result = decompress_exec(bprm, fpos, (char *)datapos, 599 full_data, 0); 600 } else 601 #endif 602 { 603 result = read_code(bprm->file, datapos, fpos, 604 full_data); 605 } 606 if (IS_ERR_VALUE(result)) { 607 ret = result; 608 pr_err("Unable to read data+bss, errno %d\n", ret); 609 vm_munmap(textpos, text_len); 610 vm_munmap(realdatastart, len); 611 goto err; 612 } 613 614 reloc = (__be32 __user *) 615 (datapos + (ntohl(hdr->reloc_start) - text_len)); 616 memp = realdatastart; 617 memp_size = len; 618 } else { 619 620 len = text_len + data_len + extra; 621 len = PAGE_ALIGN(len); 622 textpos = vm_mmap(NULL, 0, len, 623 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 624 625 if (!textpos || IS_ERR_VALUE(textpos)) { 626 ret = textpos; 627 if (!textpos) 628 ret = -ENOMEM; 629 pr_err("Unable to allocate RAM for process text/data, " 630 "errno %d\n", ret); 631 goto err; 632 } 633 634 realdatastart = textpos + ntohl(hdr->data_start); 635 datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN); 636 637 reloc = (__be32 __user *) 638 (datapos + (ntohl(hdr->reloc_start) - text_len)); 639 memp = textpos; 640 memp_size = len; 641 #ifdef CONFIG_BINFMT_ZFLAT 642 /* 643 * load it all in and treat it like a RAM load from now on 644 */ 645 if (flags & FLAT_FLAG_GZIP) { 646 #ifndef CONFIG_MMU 647 result = decompress_exec(bprm, sizeof(struct flat_hdr), 648 (((char *)textpos) + sizeof(struct flat_hdr)), 649 (text_len + full_data 650 - sizeof(struct flat_hdr)), 651 0); 652 if (datapos != realdatastart) 653 memmove((void *)datapos, (void *)realdatastart, 654 full_data); 655 #else 656 /* 657 * This is used on MMU systems mainly for testing. 658 * Let's use a kernel buffer to simplify things. 659 */ 660 long unz_text_len = text_len - sizeof(struct flat_hdr); 661 long unz_len = unz_text_len + full_data; 662 char *unz_data = vmalloc(unz_len); 663 if (!unz_data) { 664 result = -ENOMEM; 665 } else { 666 result = decompress_exec(bprm, sizeof(struct flat_hdr), 667 unz_data, unz_len, 0); 668 if (result == 0 && 669 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), 670 unz_data, unz_text_len) || 671 copy_to_user((void __user *)datapos, 672 unz_data + unz_text_len, full_data))) 673 result = -EFAULT; 674 vfree(unz_data); 675 } 676 #endif 677 } else if (flags & FLAT_FLAG_GZDATA) { 678 result = read_code(bprm->file, textpos, 0, text_len); 679 if (!IS_ERR_VALUE(result)) { 680 #ifndef CONFIG_MMU 681 result = decompress_exec(bprm, text_len, (char *) datapos, 682 full_data, 0); 683 #else 684 char *unz_data = vmalloc(full_data); 685 if (!unz_data) { 686 result = -ENOMEM; 687 } else { 688 result = decompress_exec(bprm, text_len, 689 unz_data, full_data, 0); 690 if (result == 0 && 691 copy_to_user((void __user *)datapos, 692 unz_data, full_data)) 693 result = -EFAULT; 694 vfree(unz_data); 695 } 696 #endif 697 } 698 } else 699 #endif /* CONFIG_BINFMT_ZFLAT */ 700 { 701 result = read_code(bprm->file, textpos, 0, text_len); 702 if (!IS_ERR_VALUE(result)) 703 result = read_code(bprm->file, datapos, 704 ntohl(hdr->data_start), 705 full_data); 706 } 707 if (IS_ERR_VALUE(result)) { 708 ret = result; 709 pr_err("Unable to read code+data+bss, errno %d\n", ret); 710 vm_munmap(textpos, text_len + data_len + extra); 711 goto err; 712 } 713 } 714 715 start_code = textpos + sizeof(struct flat_hdr); 716 end_code = textpos + text_len; 717 text_len -= sizeof(struct flat_hdr); /* the real code len */ 718 719 /* The main program needs a little extra setup in the task structure */ 720 if (id == 0) { 721 current->mm->start_code = start_code; 722 current->mm->end_code = end_code; 723 current->mm->start_data = datapos; 724 current->mm->end_data = datapos + data_len; 725 /* 726 * set up the brk stuff, uses any slack left in data/bss/stack 727 * allocation. We put the brk after the bss (between the bss 728 * and stack) like other platforms. 729 * Userspace code relies on the stack pointer starting out at 730 * an address right at the end of a page. 731 */ 732 current->mm->start_brk = datapos + data_len + bss_len; 733 current->mm->brk = (current->mm->start_brk + 3) & ~3; 734 #ifndef CONFIG_MMU 735 current->mm->context.end_brk = memp + memp_size - stack_len; 736 #endif 737 } 738 739 if (flags & FLAT_FLAG_KTRACE) { 740 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", 741 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 742 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", 743 id ? "Lib" : "Load", bprm->filename, 744 start_code, end_code, datapos, datapos + data_len, 745 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); 746 } 747 748 /* Store the current module values into the global library structure */ 749 libinfo->lib_list[id].start_code = start_code; 750 libinfo->lib_list[id].start_data = datapos; 751 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; 752 libinfo->lib_list[id].text_len = text_len; 753 libinfo->lib_list[id].loaded = 1; 754 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 755 libinfo->lib_list[id].build_date = ntohl(hdr->build_date); 756 757 /* 758 * We just load the allocations into some temporary memory to 759 * help simplify all this mumbo jumbo 760 * 761 * We've got two different sections of relocation entries. 762 * The first is the GOT which resides at the beginning of the data segment 763 * and is terminated with a -1. This one can be relocated in place. 764 * The second is the extra relocation entries tacked after the image's 765 * data segment. These require a little more processing as the entry is 766 * really an offset into the image which contains an offset into the 767 * image. 768 */ 769 if (flags & FLAT_FLAG_GOTPIC) { 770 for (rp = (u32 __user *)datapos; ; rp++) { 771 u32 addr, rp_val; 772 if (get_user(rp_val, rp)) 773 return -EFAULT; 774 if (rp_val == 0xffffffff) 775 break; 776 if (rp_val) { 777 addr = calc_reloc(rp_val, libinfo, id, 0); 778 if (addr == RELOC_FAILED) { 779 ret = -ENOEXEC; 780 goto err; 781 } 782 if (put_user(addr, rp)) 783 return -EFAULT; 784 } 785 } 786 } 787 788 /* 789 * Now run through the relocation entries. 790 * We've got to be careful here as C++ produces relocatable zero 791 * entries in the constructor and destructor tables which are then 792 * tested for being not zero (which will always occur unless we're 793 * based from address zero). This causes an endless loop as __start 794 * is at zero. The solution used is to not relocate zero addresses. 795 * This has the negative side effect of not allowing a global data 796 * reference to be statically initialised to _stext (I've moved 797 * __start to address 4 so that is okay). 798 */ 799 if (rev > OLD_FLAT_VERSION) { 800 for (i = 0; i < relocs; i++) { 801 u32 addr, relval; 802 __be32 tmp; 803 804 /* 805 * Get the address of the pointer to be 806 * relocated (of course, the address has to be 807 * relocated first). 808 */ 809 if (get_user(tmp, reloc + i)) 810 return -EFAULT; 811 relval = ntohl(tmp); 812 addr = flat_get_relocate_addr(relval); 813 rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1); 814 if (rp == (u32 __user *)RELOC_FAILED) { 815 ret = -ENOEXEC; 816 goto err; 817 } 818 819 /* Get the pointer's value. */ 820 ret = flat_get_addr_from_rp(rp, relval, flags, &addr); 821 if (unlikely(ret)) 822 goto err; 823 824 if (addr != 0) { 825 /* 826 * Do the relocation. PIC relocs in the data section are 827 * already in target order 828 */ 829 if ((flags & FLAT_FLAG_GOTPIC) == 0) { 830 /* 831 * Meh, the same value can have a different 832 * byte order based on a flag.. 833 */ 834 addr = ntohl((__force __be32)addr); 835 } 836 addr = calc_reloc(addr, libinfo, id, 0); 837 if (addr == RELOC_FAILED) { 838 ret = -ENOEXEC; 839 goto err; 840 } 841 842 /* Write back the relocated pointer. */ 843 ret = flat_put_addr_at_rp(rp, addr, relval); 844 if (unlikely(ret)) 845 goto err; 846 } 847 } 848 #ifdef CONFIG_BINFMT_FLAT_OLD 849 } else { 850 for (i = 0; i < relocs; i++) { 851 __be32 relval; 852 if (get_user(relval, reloc + i)) 853 return -EFAULT; 854 old_reloc(ntohl(relval)); 855 } 856 #endif /* CONFIG_BINFMT_FLAT_OLD */ 857 } 858 859 flush_icache_range(start_code, end_code); 860 861 /* zero the BSS, BRK and stack areas */ 862 if (clear_user((void __user *)(datapos + data_len), bss_len + 863 (memp + memp_size - stack_len - /* end brk */ 864 libinfo->lib_list[id].start_brk) + /* start brk */ 865 stack_len)) 866 return -EFAULT; 867 868 return 0; 869 err: 870 return ret; 871 } 872 873 874 /****************************************************************************/ 875 #ifdef CONFIG_BINFMT_SHARED_FLAT 876 877 /* 878 * Load a shared library into memory. The library gets its own data 879 * segment (including bss) but not argv/argc/environ. 880 */ 881 882 static int load_flat_shared_library(int id, struct lib_info *libs) 883 { 884 /* 885 * This is a fake bprm struct; only the members "buf", "file" and 886 * "filename" are actually used. 887 */ 888 struct linux_binprm bprm; 889 int res; 890 char buf[16]; 891 loff_t pos = 0; 892 893 memset(&bprm, 0, sizeof(bprm)); 894 895 /* Create the file name */ 896 sprintf(buf, "/lib/lib%d.so", id); 897 898 /* Open the file up */ 899 bprm.filename = buf; 900 bprm.file = open_exec(bprm.filename); 901 res = PTR_ERR(bprm.file); 902 if (IS_ERR(bprm.file)) 903 return res; 904 905 res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos); 906 907 if (res >= 0) 908 res = load_flat_file(&bprm, libs, id, NULL); 909 910 allow_write_access(bprm.file); 911 fput(bprm.file); 912 913 return res; 914 } 915 916 #endif /* CONFIG_BINFMT_SHARED_FLAT */ 917 /****************************************************************************/ 918 919 /* 920 * These are the functions used to load flat style executables and shared 921 * libraries. There is no binary dependent code anywhere else. 922 */ 923 924 static int load_flat_binary(struct linux_binprm *bprm) 925 { 926 struct lib_info libinfo; 927 struct pt_regs *regs = current_pt_regs(); 928 unsigned long stack_len = 0; 929 unsigned long start_addr; 930 int res; 931 int i, j; 932 933 memset(&libinfo, 0, sizeof(libinfo)); 934 935 /* 936 * We have to add the size of our arguments to our stack size 937 * otherwise it's too easy for users to create stack overflows 938 * by passing in a huge argument list. And yes, we have to be 939 * pedantic and include space for the argv/envp array as it may have 940 * a lot of entries. 941 */ 942 #ifndef CONFIG_MMU 943 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ 944 #endif 945 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 946 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 947 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); 948 949 res = load_flat_file(bprm, &libinfo, 0, &stack_len); 950 if (res < 0) 951 return res; 952 953 /* Update data segment pointers for all libraries */ 954 for (i = 0; i < MAX_SHARED_LIBS; i++) { 955 if (!libinfo.lib_list[i].loaded) 956 continue; 957 for (j = 0; j < MAX_SHARED_LIBS; j++) { 958 unsigned long val = libinfo.lib_list[j].loaded ? 959 libinfo.lib_list[j].start_data : UNLOADED_LIB; 960 unsigned long __user *p = (unsigned long __user *) 961 libinfo.lib_list[i].start_data; 962 p -= j + 1; 963 if (put_user(val, p)) 964 return -EFAULT; 965 } 966 } 967 968 install_exec_creds(bprm); 969 970 set_binfmt(&flat_format); 971 972 #ifdef CONFIG_MMU 973 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); 974 if (!res) 975 res = create_flat_tables(bprm, bprm->p); 976 #else 977 /* Stash our initial stack pointer into the mm structure */ 978 current->mm->start_stack = 979 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 980 pr_debug("sp=%lx\n", current->mm->start_stack); 981 982 /* copy the arg pages onto the stack */ 983 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack); 984 if (!res) 985 res = create_flat_tables(bprm, current->mm->start_stack); 986 #endif 987 if (res) 988 return res; 989 990 /* Fake some return addresses to ensure the call chain will 991 * initialise library in order for us. We are required to call 992 * lib 1 first, then 2, ... and finally the main program (id 0). 993 */ 994 start_addr = libinfo.lib_list[0].entry; 995 996 #ifdef CONFIG_BINFMT_SHARED_FLAT 997 for (i = MAX_SHARED_LIBS-1; i > 0; i--) { 998 if (libinfo.lib_list[i].loaded) { 999 /* Push previos first to call address */ 1000 unsigned long __user *sp; 1001 current->mm->start_stack -= sizeof(unsigned long); 1002 sp = (unsigned long __user *)current->mm->start_stack; 1003 __put_user(start_addr, sp); 1004 start_addr = libinfo.lib_list[i].entry; 1005 } 1006 } 1007 #endif 1008 1009 #ifdef FLAT_PLAT_INIT 1010 FLAT_PLAT_INIT(regs); 1011 #endif 1012 1013 finalize_exec(bprm); 1014 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", 1015 regs, start_addr, current->mm->start_stack); 1016 start_thread(regs, start_addr, current->mm->start_stack); 1017 1018 return 0; 1019 } 1020 1021 /****************************************************************************/ 1022 1023 static int __init init_flat_binfmt(void) 1024 { 1025 register_binfmt(&flat_format); 1026 return 0; 1027 } 1028 core_initcall(init_flat_binfmt); 1029 1030 /****************************************************************************/ 1031