1 /* 2 * linux/fs/exec.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 /* 8 * #!-checking implemented by tytso. 9 */ 10 /* 11 * Demand-loading implemented 01.12.91 - no need to read anything but 12 * the header into memory. The inode of the executable is put into 13 * "current->executable", and page faults do the actual loading. Clean. 14 * 15 * Once more I can proudly say that linux stood up to being changed: it 16 * was less than 2 hours work to get demand-loading completely implemented. 17 * 18 * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, 19 * current->executable is only used by the procfs. This allows a dispatch 20 * table to check for several different types of binary formats. We keep 21 * trying until we recognize the file or we run out of supported binary 22 * formats. 23 */ 24 25 #include <linux/slab.h> 26 #include <linux/file.h> 27 #include <linux/fdtable.h> 28 #include <linux/mm.h> 29 #include <linux/stat.h> 30 #include <linux/fcntl.h> 31 #include <linux/swap.h> 32 #include <linux/string.h> 33 #include <linux/init.h> 34 #include <linux/pagemap.h> 35 #include <linux/perf_event.h> 36 #include <linux/highmem.h> 37 #include <linux/spinlock.h> 38 #include <linux/key.h> 39 #include <linux/personality.h> 40 #include <linux/binfmts.h> 41 #include <linux/utsname.h> 42 #include <linux/pid_namespace.h> 43 #include <linux/module.h> 44 #include <linux/namei.h> 45 #include <linux/mount.h> 46 #include <linux/security.h> 47 #include <linux/syscalls.h> 48 #include <linux/tsacct_kern.h> 49 #include <linux/cn_proc.h> 50 #include <linux/audit.h> 51 #include <linux/tracehook.h> 52 #include <linux/kmod.h> 53 #include <linux/fsnotify.h> 54 #include <linux/fs_struct.h> 55 #include <linux/pipe_fs_i.h> 56 #include <linux/oom.h> 57 #include <linux/compat.h> 58 59 #include <asm/uaccess.h> 60 #include <asm/mmu_context.h> 61 #include <asm/tlb.h> 62 #include <asm/exec.h> 63 64 #include <trace/events/task.h> 65 #include "internal.h" 66 67 #include <trace/events/sched.h> 68 69 int core_uses_pid; 70 char core_pattern[CORENAME_MAX_SIZE] = "core"; 71 unsigned int core_pipe_limit; 72 int suid_dumpable = 0; 73 74 struct core_name { 75 char *corename; 76 int used, size; 77 }; 78 static atomic_t call_count = ATOMIC_INIT(1); 79 80 /* The maximal length of core_pattern is also specified in sysctl.c */ 81 82 static LIST_HEAD(formats); 83 static DEFINE_RWLOCK(binfmt_lock); 84 85 void __register_binfmt(struct linux_binfmt * fmt, int insert) 86 { 87 BUG_ON(!fmt); 88 write_lock(&binfmt_lock); 89 insert ? list_add(&fmt->lh, &formats) : 90 list_add_tail(&fmt->lh, &formats); 91 write_unlock(&binfmt_lock); 92 } 93 94 EXPORT_SYMBOL(__register_binfmt); 95 96 void unregister_binfmt(struct linux_binfmt * fmt) 97 { 98 write_lock(&binfmt_lock); 99 list_del(&fmt->lh); 100 write_unlock(&binfmt_lock); 101 } 102 103 EXPORT_SYMBOL(unregister_binfmt); 104 105 static inline void put_binfmt(struct linux_binfmt * fmt) 106 { 107 module_put(fmt->module); 108 } 109 110 /* 111 * Note that a shared library must be both readable and executable due to 112 * security reasons. 113 * 114 * Also note that we take the address to load from from the file itself. 115 */ 116 SYSCALL_DEFINE1(uselib, const char __user *, library) 117 { 118 struct file *file; 119 char *tmp = getname(library); 120 int error = PTR_ERR(tmp); 121 static const struct open_flags uselib_flags = { 122 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 123 .acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN, 124 .intent = LOOKUP_OPEN 125 }; 126 127 if (IS_ERR(tmp)) 128 goto out; 129 130 file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW); 131 putname(tmp); 132 error = PTR_ERR(file); 133 if (IS_ERR(file)) 134 goto out; 135 136 error = -EINVAL; 137 if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) 138 goto exit; 139 140 error = -EACCES; 141 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) 142 goto exit; 143 144 fsnotify_open(file); 145 146 error = -ENOEXEC; 147 if(file->f_op) { 148 struct linux_binfmt * fmt; 149 150 read_lock(&binfmt_lock); 151 list_for_each_entry(fmt, &formats, lh) { 152 if (!fmt->load_shlib) 153 continue; 154 if (!try_module_get(fmt->module)) 155 continue; 156 read_unlock(&binfmt_lock); 157 error = fmt->load_shlib(file); 158 read_lock(&binfmt_lock); 159 put_binfmt(fmt); 160 if (error != -ENOEXEC) 161 break; 162 } 163 read_unlock(&binfmt_lock); 164 } 165 exit: 166 fput(file); 167 out: 168 return error; 169 } 170 171 #ifdef CONFIG_MMU 172 /* 173 * The nascent bprm->mm is not visible until exec_mmap() but it can 174 * use a lot of memory, account these pages in current->mm temporary 175 * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we 176 * change the counter back via acct_arg_size(0). 177 */ 178 static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) 179 { 180 struct mm_struct *mm = current->mm; 181 long diff = (long)(pages - bprm->vma_pages); 182 183 if (!mm || !diff) 184 return; 185 186 bprm->vma_pages = pages; 187 add_mm_counter(mm, MM_ANONPAGES, diff); 188 } 189 190 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, 191 int write) 192 { 193 struct page *page; 194 int ret; 195 196 #ifdef CONFIG_STACK_GROWSUP 197 if (write) { 198 ret = expand_downwards(bprm->vma, pos); 199 if (ret < 0) 200 return NULL; 201 } 202 #endif 203 ret = get_user_pages(current, bprm->mm, pos, 204 1, write, 1, &page, NULL); 205 if (ret <= 0) 206 return NULL; 207 208 if (write) { 209 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; 210 struct rlimit *rlim; 211 212 acct_arg_size(bprm, size / PAGE_SIZE); 213 214 /* 215 * We've historically supported up to 32 pages (ARG_MAX) 216 * of argument strings even with small stacks 217 */ 218 if (size <= ARG_MAX) 219 return page; 220 221 /* 222 * Limit to 1/4-th the stack size for the argv+env strings. 223 * This ensures that: 224 * - the remaining binfmt code will not run out of stack space, 225 * - the program will have a reasonable amount of stack left 226 * to work from. 227 */ 228 rlim = current->signal->rlim; 229 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { 230 put_page(page); 231 return NULL; 232 } 233 } 234 235 return page; 236 } 237 238 static void put_arg_page(struct page *page) 239 { 240 put_page(page); 241 } 242 243 static void free_arg_page(struct linux_binprm *bprm, int i) 244 { 245 } 246 247 static void free_arg_pages(struct linux_binprm *bprm) 248 { 249 } 250 251 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, 252 struct page *page) 253 { 254 flush_cache_page(bprm->vma, pos, page_to_pfn(page)); 255 } 256 257 static int __bprm_mm_init(struct linux_binprm *bprm) 258 { 259 int err; 260 struct vm_area_struct *vma = NULL; 261 struct mm_struct *mm = bprm->mm; 262 263 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 264 if (!vma) 265 return -ENOMEM; 266 267 down_write(&mm->mmap_sem); 268 vma->vm_mm = mm; 269 270 /* 271 * Place the stack at the largest stack address the architecture 272 * supports. Later, we'll move this to an appropriate place. We don't 273 * use STACK_TOP because that can depend on attributes which aren't 274 * configured yet. 275 */ 276 BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); 277 vma->vm_end = STACK_TOP_MAX; 278 vma->vm_start = vma->vm_end - PAGE_SIZE; 279 vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; 280 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 281 INIT_LIST_HEAD(&vma->anon_vma_chain); 282 283 err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1); 284 if (err) 285 goto err; 286 287 err = insert_vm_struct(mm, vma); 288 if (err) 289 goto err; 290 291 mm->stack_vm = mm->total_vm = 1; 292 up_write(&mm->mmap_sem); 293 bprm->p = vma->vm_end - sizeof(void *); 294 return 0; 295 err: 296 up_write(&mm->mmap_sem); 297 bprm->vma = NULL; 298 kmem_cache_free(vm_area_cachep, vma); 299 return err; 300 } 301 302 static bool valid_arg_len(struct linux_binprm *bprm, long len) 303 { 304 return len <= MAX_ARG_STRLEN; 305 } 306 307 #else 308 309 static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) 310 { 311 } 312 313 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, 314 int write) 315 { 316 struct page *page; 317 318 page = bprm->page[pos / PAGE_SIZE]; 319 if (!page && write) { 320 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); 321 if (!page) 322 return NULL; 323 bprm->page[pos / PAGE_SIZE] = page; 324 } 325 326 return page; 327 } 328 329 static void put_arg_page(struct page *page) 330 { 331 } 332 333 static void free_arg_page(struct linux_binprm *bprm, int i) 334 { 335 if (bprm->page[i]) { 336 __free_page(bprm->page[i]); 337 bprm->page[i] = NULL; 338 } 339 } 340 341 static void free_arg_pages(struct linux_binprm *bprm) 342 { 343 int i; 344 345 for (i = 0; i < MAX_ARG_PAGES; i++) 346 free_arg_page(bprm, i); 347 } 348 349 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, 350 struct page *page) 351 { 352 } 353 354 static int __bprm_mm_init(struct linux_binprm *bprm) 355 { 356 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); 357 return 0; 358 } 359 360 static bool valid_arg_len(struct linux_binprm *bprm, long len) 361 { 362 return len <= bprm->p; 363 } 364 365 #endif /* CONFIG_MMU */ 366 367 /* 368 * Create a new mm_struct and populate it with a temporary stack 369 * vm_area_struct. We don't have enough context at this point to set the stack 370 * flags, permissions, and offset, so we use temporary values. We'll update 371 * them later in setup_arg_pages(). 372 */ 373 int bprm_mm_init(struct linux_binprm *bprm) 374 { 375 int err; 376 struct mm_struct *mm = NULL; 377 378 bprm->mm = mm = mm_alloc(); 379 err = -ENOMEM; 380 if (!mm) 381 goto err; 382 383 err = init_new_context(current, mm); 384 if (err) 385 goto err; 386 387 err = __bprm_mm_init(bprm); 388 if (err) 389 goto err; 390 391 return 0; 392 393 err: 394 if (mm) { 395 bprm->mm = NULL; 396 mmdrop(mm); 397 } 398 399 return err; 400 } 401 402 struct user_arg_ptr { 403 #ifdef CONFIG_COMPAT 404 bool is_compat; 405 #endif 406 union { 407 const char __user *const __user *native; 408 #ifdef CONFIG_COMPAT 409 compat_uptr_t __user *compat; 410 #endif 411 } ptr; 412 }; 413 414 static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) 415 { 416 const char __user *native; 417 418 #ifdef CONFIG_COMPAT 419 if (unlikely(argv.is_compat)) { 420 compat_uptr_t compat; 421 422 if (get_user(compat, argv.ptr.compat + nr)) 423 return ERR_PTR(-EFAULT); 424 425 return compat_ptr(compat); 426 } 427 #endif 428 429 if (get_user(native, argv.ptr.native + nr)) 430 return ERR_PTR(-EFAULT); 431 432 return native; 433 } 434 435 /* 436 * count() counts the number of strings in array ARGV. 437 */ 438 static int count(struct user_arg_ptr argv, int max) 439 { 440 int i = 0; 441 442 if (argv.ptr.native != NULL) { 443 for (;;) { 444 const char __user *p = get_user_arg_ptr(argv, i); 445 446 if (!p) 447 break; 448 449 if (IS_ERR(p)) 450 return -EFAULT; 451 452 if (i++ >= max) 453 return -E2BIG; 454 455 if (fatal_signal_pending(current)) 456 return -ERESTARTNOHAND; 457 cond_resched(); 458 } 459 } 460 return i; 461 } 462 463 /* 464 * 'copy_strings()' copies argument/environment strings from the old 465 * processes's memory to the new process's stack. The call to get_user_pages() 466 * ensures the destination page is created and not swapped out. 467 */ 468 static int copy_strings(int argc, struct user_arg_ptr argv, 469 struct linux_binprm *bprm) 470 { 471 struct page *kmapped_page = NULL; 472 char *kaddr = NULL; 473 unsigned long kpos = 0; 474 int ret; 475 476 while (argc-- > 0) { 477 const char __user *str; 478 int len; 479 unsigned long pos; 480 481 ret = -EFAULT; 482 str = get_user_arg_ptr(argv, argc); 483 if (IS_ERR(str)) 484 goto out; 485 486 len = strnlen_user(str, MAX_ARG_STRLEN); 487 if (!len) 488 goto out; 489 490 ret = -E2BIG; 491 if (!valid_arg_len(bprm, len)) 492 goto out; 493 494 /* We're going to work our way backwords. */ 495 pos = bprm->p; 496 str += len; 497 bprm->p -= len; 498 499 while (len > 0) { 500 int offset, bytes_to_copy; 501 502 if (fatal_signal_pending(current)) { 503 ret = -ERESTARTNOHAND; 504 goto out; 505 } 506 cond_resched(); 507 508 offset = pos % PAGE_SIZE; 509 if (offset == 0) 510 offset = PAGE_SIZE; 511 512 bytes_to_copy = offset; 513 if (bytes_to_copy > len) 514 bytes_to_copy = len; 515 516 offset -= bytes_to_copy; 517 pos -= bytes_to_copy; 518 str -= bytes_to_copy; 519 len -= bytes_to_copy; 520 521 if (!kmapped_page || kpos != (pos & PAGE_MASK)) { 522 struct page *page; 523 524 page = get_arg_page(bprm, pos, 1); 525 if (!page) { 526 ret = -E2BIG; 527 goto out; 528 } 529 530 if (kmapped_page) { 531 flush_kernel_dcache_page(kmapped_page); 532 kunmap(kmapped_page); 533 put_arg_page(kmapped_page); 534 } 535 kmapped_page = page; 536 kaddr = kmap(kmapped_page); 537 kpos = pos & PAGE_MASK; 538 flush_arg_page(bprm, kpos, kmapped_page); 539 } 540 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { 541 ret = -EFAULT; 542 goto out; 543 } 544 } 545 } 546 ret = 0; 547 out: 548 if (kmapped_page) { 549 flush_kernel_dcache_page(kmapped_page); 550 kunmap(kmapped_page); 551 put_arg_page(kmapped_page); 552 } 553 return ret; 554 } 555 556 /* 557 * Like copy_strings, but get argv and its values from kernel memory. 558 */ 559 int copy_strings_kernel(int argc, const char *const *__argv, 560 struct linux_binprm *bprm) 561 { 562 int r; 563 mm_segment_t oldfs = get_fs(); 564 struct user_arg_ptr argv = { 565 .ptr.native = (const char __user *const __user *)__argv, 566 }; 567 568 set_fs(KERNEL_DS); 569 r = copy_strings(argc, argv, bprm); 570 set_fs(oldfs); 571 572 return r; 573 } 574 EXPORT_SYMBOL(copy_strings_kernel); 575 576 #ifdef CONFIG_MMU 577 578 /* 579 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once 580 * the binfmt code determines where the new stack should reside, we shift it to 581 * its final location. The process proceeds as follows: 582 * 583 * 1) Use shift to calculate the new vma endpoints. 584 * 2) Extend vma to cover both the old and new ranges. This ensures the 585 * arguments passed to subsequent functions are consistent. 586 * 3) Move vma's page tables to the new range. 587 * 4) Free up any cleared pgd range. 588 * 5) Shrink the vma to cover only the new range. 589 */ 590 static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 591 { 592 struct mm_struct *mm = vma->vm_mm; 593 unsigned long old_start = vma->vm_start; 594 unsigned long old_end = vma->vm_end; 595 unsigned long length = old_end - old_start; 596 unsigned long new_start = old_start - shift; 597 unsigned long new_end = old_end - shift; 598 struct mmu_gather tlb; 599 600 BUG_ON(new_start > new_end); 601 602 /* 603 * ensure there are no vmas between where we want to go 604 * and where we are 605 */ 606 if (vma != find_vma(mm, new_start)) 607 return -EFAULT; 608 609 /* 610 * cover the whole range: [new_start, old_end) 611 */ 612 if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) 613 return -ENOMEM; 614 615 /* 616 * move the page tables downwards, on failure we rely on 617 * process cleanup to remove whatever mess we made. 618 */ 619 if (length != move_page_tables(vma, old_start, 620 vma, new_start, length)) 621 return -ENOMEM; 622 623 lru_add_drain(); 624 tlb_gather_mmu(&tlb, mm, 0); 625 if (new_end > old_start) { 626 /* 627 * when the old and new regions overlap clear from new_end. 628 */ 629 free_pgd_range(&tlb, new_end, old_end, new_end, 630 vma->vm_next ? vma->vm_next->vm_start : 0); 631 } else { 632 /* 633 * otherwise, clean from old_start; this is done to not touch 634 * the address space in [new_end, old_start) some architectures 635 * have constraints on va-space that make this illegal (IA64) - 636 * for the others its just a little faster. 637 */ 638 free_pgd_range(&tlb, old_start, old_end, new_end, 639 vma->vm_next ? vma->vm_next->vm_start : 0); 640 } 641 tlb_finish_mmu(&tlb, new_end, old_end); 642 643 /* 644 * Shrink the vma to just the new range. Always succeeds. 645 */ 646 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); 647 648 return 0; 649 } 650 651 /* 652 * Finalizes the stack vm_area_struct. The flags and permissions are updated, 653 * the stack is optionally relocated, and some extra space is added. 654 */ 655 int setup_arg_pages(struct linux_binprm *bprm, 656 unsigned long stack_top, 657 int executable_stack) 658 { 659 unsigned long ret; 660 unsigned long stack_shift; 661 struct mm_struct *mm = current->mm; 662 struct vm_area_struct *vma = bprm->vma; 663 struct vm_area_struct *prev = NULL; 664 unsigned long vm_flags; 665 unsigned long stack_base; 666 unsigned long stack_size; 667 unsigned long stack_expand; 668 unsigned long rlim_stack; 669 670 #ifdef CONFIG_STACK_GROWSUP 671 /* Limit stack size to 1GB */ 672 stack_base = rlimit_max(RLIMIT_STACK); 673 if (stack_base > (1 << 30)) 674 stack_base = 1 << 30; 675 676 /* Make sure we didn't let the argument array grow too large. */ 677 if (vma->vm_end - vma->vm_start > stack_base) 678 return -ENOMEM; 679 680 stack_base = PAGE_ALIGN(stack_top - stack_base); 681 682 stack_shift = vma->vm_start - stack_base; 683 mm->arg_start = bprm->p - stack_shift; 684 bprm->p = vma->vm_end - stack_shift; 685 #else 686 stack_top = arch_align_stack(stack_top); 687 stack_top = PAGE_ALIGN(stack_top); 688 689 if (unlikely(stack_top < mmap_min_addr) || 690 unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) 691 return -ENOMEM; 692 693 stack_shift = vma->vm_end - stack_top; 694 695 bprm->p -= stack_shift; 696 mm->arg_start = bprm->p; 697 #endif 698 699 if (bprm->loader) 700 bprm->loader -= stack_shift; 701 bprm->exec -= stack_shift; 702 703 down_write(&mm->mmap_sem); 704 vm_flags = VM_STACK_FLAGS; 705 706 /* 707 * Adjust stack execute permissions; explicitly enable for 708 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone 709 * (arch default) otherwise. 710 */ 711 if (unlikely(executable_stack == EXSTACK_ENABLE_X)) 712 vm_flags |= VM_EXEC; 713 else if (executable_stack == EXSTACK_DISABLE_X) 714 vm_flags &= ~VM_EXEC; 715 vm_flags |= mm->def_flags; 716 vm_flags |= VM_STACK_INCOMPLETE_SETUP; 717 718 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, 719 vm_flags); 720 if (ret) 721 goto out_unlock; 722 BUG_ON(prev != vma); 723 724 /* Move stack pages down in memory. */ 725 if (stack_shift) { 726 ret = shift_arg_pages(vma, stack_shift); 727 if (ret) 728 goto out_unlock; 729 } 730 731 /* mprotect_fixup is overkill to remove the temporary stack flags */ 732 vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; 733 734 stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ 735 stack_size = vma->vm_end - vma->vm_start; 736 /* 737 * Align this down to a page boundary as expand_stack 738 * will align it up. 739 */ 740 rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; 741 #ifdef CONFIG_STACK_GROWSUP 742 if (stack_size + stack_expand > rlim_stack) 743 stack_base = vma->vm_start + rlim_stack; 744 else 745 stack_base = vma->vm_end + stack_expand; 746 #else 747 if (stack_size + stack_expand > rlim_stack) 748 stack_base = vma->vm_end - rlim_stack; 749 else 750 stack_base = vma->vm_start - stack_expand; 751 #endif 752 current->mm->start_stack = bprm->p; 753 ret = expand_stack(vma, stack_base); 754 if (ret) 755 ret = -EFAULT; 756 757 out_unlock: 758 up_write(&mm->mmap_sem); 759 return ret; 760 } 761 EXPORT_SYMBOL(setup_arg_pages); 762 763 #endif /* CONFIG_MMU */ 764 765 struct file *open_exec(const char *name) 766 { 767 struct file *file; 768 int err; 769 static const struct open_flags open_exec_flags = { 770 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 771 .acc_mode = MAY_EXEC | MAY_OPEN, 772 .intent = LOOKUP_OPEN 773 }; 774 775 file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW); 776 if (IS_ERR(file)) 777 goto out; 778 779 err = -EACCES; 780 if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) 781 goto exit; 782 783 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) 784 goto exit; 785 786 fsnotify_open(file); 787 788 err = deny_write_access(file); 789 if (err) 790 goto exit; 791 792 out: 793 return file; 794 795 exit: 796 fput(file); 797 return ERR_PTR(err); 798 } 799 EXPORT_SYMBOL(open_exec); 800 801 int kernel_read(struct file *file, loff_t offset, 802 char *addr, unsigned long count) 803 { 804 mm_segment_t old_fs; 805 loff_t pos = offset; 806 int result; 807 808 old_fs = get_fs(); 809 set_fs(get_ds()); 810 /* The cast to a user pointer is valid due to the set_fs() */ 811 result = vfs_read(file, (void __user *)addr, count, &pos); 812 set_fs(old_fs); 813 return result; 814 } 815 816 EXPORT_SYMBOL(kernel_read); 817 818 static int exec_mmap(struct mm_struct *mm) 819 { 820 struct task_struct *tsk; 821 struct mm_struct * old_mm, *active_mm; 822 823 /* Notify parent that we're no longer interested in the old VM */ 824 tsk = current; 825 old_mm = current->mm; 826 sync_mm_rss(old_mm); 827 mm_release(tsk, old_mm); 828 829 if (old_mm) { 830 /* 831 * Make sure that if there is a core dump in progress 832 * for the old mm, we get out and die instead of going 833 * through with the exec. We must hold mmap_sem around 834 * checking core_state and changing tsk->mm. 835 */ 836 down_read(&old_mm->mmap_sem); 837 if (unlikely(old_mm->core_state)) { 838 up_read(&old_mm->mmap_sem); 839 return -EINTR; 840 } 841 } 842 task_lock(tsk); 843 active_mm = tsk->active_mm; 844 tsk->mm = mm; 845 tsk->active_mm = mm; 846 activate_mm(active_mm, mm); 847 task_unlock(tsk); 848 arch_pick_mmap_layout(mm); 849 if (old_mm) { 850 up_read(&old_mm->mmap_sem); 851 BUG_ON(active_mm != old_mm); 852 setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); 853 mm_update_next_owner(old_mm); 854 mmput(old_mm); 855 return 0; 856 } 857 mmdrop(active_mm); 858 return 0; 859 } 860 861 /* 862 * This function makes sure the current process has its own signal table, 863 * so that flush_signal_handlers can later reset the handlers without 864 * disturbing other processes. (Other processes might share the signal 865 * table via the CLONE_SIGHAND option to clone().) 866 */ 867 static int de_thread(struct task_struct *tsk) 868 { 869 struct signal_struct *sig = tsk->signal; 870 struct sighand_struct *oldsighand = tsk->sighand; 871 spinlock_t *lock = &oldsighand->siglock; 872 873 if (thread_group_empty(tsk)) 874 goto no_thread_group; 875 876 /* 877 * Kill all other threads in the thread group. 878 */ 879 spin_lock_irq(lock); 880 if (signal_group_exit(sig)) { 881 /* 882 * Another group action in progress, just 883 * return so that the signal is processed. 884 */ 885 spin_unlock_irq(lock); 886 return -EAGAIN; 887 } 888 889 sig->group_exit_task = tsk; 890 sig->notify_count = zap_other_threads(tsk); 891 if (!thread_group_leader(tsk)) 892 sig->notify_count--; 893 894 while (sig->notify_count) { 895 __set_current_state(TASK_UNINTERRUPTIBLE); 896 spin_unlock_irq(lock); 897 schedule(); 898 spin_lock_irq(lock); 899 } 900 spin_unlock_irq(lock); 901 902 /* 903 * At this point all other threads have exited, all we have to 904 * do is to wait for the thread group leader to become inactive, 905 * and to assume its PID: 906 */ 907 if (!thread_group_leader(tsk)) { 908 struct task_struct *leader = tsk->group_leader; 909 910 sig->notify_count = -1; /* for exit_notify() */ 911 for (;;) { 912 write_lock_irq(&tasklist_lock); 913 if (likely(leader->exit_state)) 914 break; 915 __set_current_state(TASK_UNINTERRUPTIBLE); 916 write_unlock_irq(&tasklist_lock); 917 schedule(); 918 } 919 920 /* 921 * The only record we have of the real-time age of a 922 * process, regardless of execs it's done, is start_time. 923 * All the past CPU time is accumulated in signal_struct 924 * from sister threads now dead. But in this non-leader 925 * exec, nothing survives from the original leader thread, 926 * whose birth marks the true age of this process now. 927 * When we take on its identity by switching to its PID, we 928 * also take its birthdate (always earlier than our own). 929 */ 930 tsk->start_time = leader->start_time; 931 932 BUG_ON(!same_thread_group(leader, tsk)); 933 BUG_ON(has_group_leader_pid(tsk)); 934 /* 935 * An exec() starts a new thread group with the 936 * TGID of the previous thread group. Rehash the 937 * two threads with a switched PID, and release 938 * the former thread group leader: 939 */ 940 941 /* Become a process group leader with the old leader's pid. 942 * The old leader becomes a thread of the this thread group. 943 * Note: The old leader also uses this pid until release_task 944 * is called. Odd but simple and correct. 945 */ 946 detach_pid(tsk, PIDTYPE_PID); 947 tsk->pid = leader->pid; 948 attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); 949 transfer_pid(leader, tsk, PIDTYPE_PGID); 950 transfer_pid(leader, tsk, PIDTYPE_SID); 951 952 list_replace_rcu(&leader->tasks, &tsk->tasks); 953 list_replace_init(&leader->sibling, &tsk->sibling); 954 955 tsk->group_leader = tsk; 956 leader->group_leader = tsk; 957 958 tsk->exit_signal = SIGCHLD; 959 leader->exit_signal = -1; 960 961 BUG_ON(leader->exit_state != EXIT_ZOMBIE); 962 leader->exit_state = EXIT_DEAD; 963 964 /* 965 * We are going to release_task()->ptrace_unlink() silently, 966 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees 967 * the tracer wont't block again waiting for this thread. 968 */ 969 if (unlikely(leader->ptrace)) 970 __wake_up_parent(leader, leader->parent); 971 write_unlock_irq(&tasklist_lock); 972 973 release_task(leader); 974 } 975 976 sig->group_exit_task = NULL; 977 sig->notify_count = 0; 978 979 no_thread_group: 980 /* we have changed execution domain */ 981 tsk->exit_signal = SIGCHLD; 982 983 exit_itimers(sig); 984 flush_itimer_signals(); 985 986 if (atomic_read(&oldsighand->count) != 1) { 987 struct sighand_struct *newsighand; 988 /* 989 * This ->sighand is shared with the CLONE_SIGHAND 990 * but not CLONE_THREAD task, switch to the new one. 991 */ 992 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); 993 if (!newsighand) 994 return -ENOMEM; 995 996 atomic_set(&newsighand->count, 1); 997 memcpy(newsighand->action, oldsighand->action, 998 sizeof(newsighand->action)); 999 1000 write_lock_irq(&tasklist_lock); 1001 spin_lock(&oldsighand->siglock); 1002 rcu_assign_pointer(tsk->sighand, newsighand); 1003 spin_unlock(&oldsighand->siglock); 1004 write_unlock_irq(&tasklist_lock); 1005 1006 __cleanup_sighand(oldsighand); 1007 } 1008 1009 BUG_ON(!thread_group_leader(tsk)); 1010 return 0; 1011 } 1012 1013 /* 1014 * These functions flushes out all traces of the currently running executable 1015 * so that a new one can be started 1016 */ 1017 static void flush_old_files(struct files_struct * files) 1018 { 1019 long j = -1; 1020 struct fdtable *fdt; 1021 1022 spin_lock(&files->file_lock); 1023 for (;;) { 1024 unsigned long set, i; 1025 1026 j++; 1027 i = j * __NFDBITS; 1028 fdt = files_fdtable(files); 1029 if (i >= fdt->max_fds) 1030 break; 1031 set = fdt->close_on_exec[j]; 1032 if (!set) 1033 continue; 1034 fdt->close_on_exec[j] = 0; 1035 spin_unlock(&files->file_lock); 1036 for ( ; set ; i++,set >>= 1) { 1037 if (set & 1) { 1038 sys_close(i); 1039 } 1040 } 1041 spin_lock(&files->file_lock); 1042 1043 } 1044 spin_unlock(&files->file_lock); 1045 } 1046 1047 char *get_task_comm(char *buf, struct task_struct *tsk) 1048 { 1049 /* buf must be at least sizeof(tsk->comm) in size */ 1050 task_lock(tsk); 1051 strncpy(buf, tsk->comm, sizeof(tsk->comm)); 1052 task_unlock(tsk); 1053 return buf; 1054 } 1055 EXPORT_SYMBOL_GPL(get_task_comm); 1056 1057 void set_task_comm(struct task_struct *tsk, char *buf) 1058 { 1059 task_lock(tsk); 1060 1061 trace_task_rename(tsk, buf); 1062 1063 /* 1064 * Threads may access current->comm without holding 1065 * the task lock, so write the string carefully. 1066 * Readers without a lock may see incomplete new 1067 * names but are safe from non-terminating string reads. 1068 */ 1069 memset(tsk->comm, 0, TASK_COMM_LEN); 1070 wmb(); 1071 strlcpy(tsk->comm, buf, sizeof(tsk->comm)); 1072 task_unlock(tsk); 1073 perf_event_comm(tsk); 1074 } 1075 1076 static void filename_to_taskname(char *tcomm, const char *fn, unsigned int len) 1077 { 1078 int i, ch; 1079 1080 /* Copies the binary name from after last slash */ 1081 for (i = 0; (ch = *(fn++)) != '\0';) { 1082 if (ch == '/') 1083 i = 0; /* overwrite what we wrote */ 1084 else 1085 if (i < len - 1) 1086 tcomm[i++] = ch; 1087 } 1088 tcomm[i] = '\0'; 1089 } 1090 1091 int flush_old_exec(struct linux_binprm * bprm) 1092 { 1093 int retval; 1094 1095 /* 1096 * Make sure we have a private signal table and that 1097 * we are unassociated from the previous thread group. 1098 */ 1099 retval = de_thread(current); 1100 if (retval) 1101 goto out; 1102 1103 set_mm_exe_file(bprm->mm, bprm->file); 1104 1105 filename_to_taskname(bprm->tcomm, bprm->filename, sizeof(bprm->tcomm)); 1106 /* 1107 * Release all of the old mmap stuff 1108 */ 1109 acct_arg_size(bprm, 0); 1110 retval = exec_mmap(bprm->mm); 1111 if (retval) 1112 goto out; 1113 1114 bprm->mm = NULL; /* We're using it now */ 1115 1116 set_fs(USER_DS); 1117 current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD); 1118 flush_thread(); 1119 current->personality &= ~bprm->per_clear; 1120 1121 return 0; 1122 1123 out: 1124 return retval; 1125 } 1126 EXPORT_SYMBOL(flush_old_exec); 1127 1128 void would_dump(struct linux_binprm *bprm, struct file *file) 1129 { 1130 if (inode_permission(file->f_path.dentry->d_inode, MAY_READ) < 0) 1131 bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; 1132 } 1133 EXPORT_SYMBOL(would_dump); 1134 1135 void setup_new_exec(struct linux_binprm * bprm) 1136 { 1137 arch_pick_mmap_layout(current->mm); 1138 1139 /* This is the point of no return */ 1140 current->sas_ss_sp = current->sas_ss_size = 0; 1141 1142 if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) 1143 set_dumpable(current->mm, 1); 1144 else 1145 set_dumpable(current->mm, suid_dumpable); 1146 1147 set_task_comm(current, bprm->tcomm); 1148 1149 /* Set the new mm task size. We have to do that late because it may 1150 * depend on TIF_32BIT which is only updated in flush_thread() on 1151 * some architectures like powerpc 1152 */ 1153 current->mm->task_size = TASK_SIZE; 1154 1155 /* install the new credentials */ 1156 if (!uid_eq(bprm->cred->uid, current_euid()) || 1157 !gid_eq(bprm->cred->gid, current_egid())) { 1158 current->pdeath_signal = 0; 1159 } else { 1160 would_dump(bprm, bprm->file); 1161 if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) 1162 set_dumpable(current->mm, suid_dumpable); 1163 } 1164 1165 /* 1166 * Flush performance counters when crossing a 1167 * security domain: 1168 */ 1169 if (!get_dumpable(current->mm)) 1170 perf_event_exit_task(current); 1171 1172 /* An exec changes our domain. We are no longer part of the thread 1173 group */ 1174 1175 current->self_exec_id++; 1176 1177 flush_signal_handlers(current, 0); 1178 flush_old_files(current->files); 1179 } 1180 EXPORT_SYMBOL(setup_new_exec); 1181 1182 /* 1183 * Prepare credentials and lock ->cred_guard_mutex. 1184 * install_exec_creds() commits the new creds and drops the lock. 1185 * Or, if exec fails before, free_bprm() should release ->cred and 1186 * and unlock. 1187 */ 1188 int prepare_bprm_creds(struct linux_binprm *bprm) 1189 { 1190 if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) 1191 return -ERESTARTNOINTR; 1192 1193 bprm->cred = prepare_exec_creds(); 1194 if (likely(bprm->cred)) 1195 return 0; 1196 1197 mutex_unlock(¤t->signal->cred_guard_mutex); 1198 return -ENOMEM; 1199 } 1200 1201 void free_bprm(struct linux_binprm *bprm) 1202 { 1203 free_arg_pages(bprm); 1204 if (bprm->cred) { 1205 mutex_unlock(¤t->signal->cred_guard_mutex); 1206 abort_creds(bprm->cred); 1207 } 1208 kfree(bprm); 1209 } 1210 1211 /* 1212 * install the new credentials for this executable 1213 */ 1214 void install_exec_creds(struct linux_binprm *bprm) 1215 { 1216 security_bprm_committing_creds(bprm); 1217 1218 commit_creds(bprm->cred); 1219 bprm->cred = NULL; 1220 /* 1221 * cred_guard_mutex must be held at least to this point to prevent 1222 * ptrace_attach() from altering our determination of the task's 1223 * credentials; any time after this it may be unlocked. 1224 */ 1225 security_bprm_committed_creds(bprm); 1226 mutex_unlock(¤t->signal->cred_guard_mutex); 1227 } 1228 EXPORT_SYMBOL(install_exec_creds); 1229 1230 /* 1231 * determine how safe it is to execute the proposed program 1232 * - the caller must hold ->cred_guard_mutex to protect against 1233 * PTRACE_ATTACH 1234 */ 1235 static int check_unsafe_exec(struct linux_binprm *bprm) 1236 { 1237 struct task_struct *p = current, *t; 1238 unsigned n_fs; 1239 int res = 0; 1240 1241 if (p->ptrace) { 1242 if (p->ptrace & PT_PTRACE_CAP) 1243 bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; 1244 else 1245 bprm->unsafe |= LSM_UNSAFE_PTRACE; 1246 } 1247 1248 /* 1249 * This isn't strictly necessary, but it makes it harder for LSMs to 1250 * mess up. 1251 */ 1252 if (current->no_new_privs) 1253 bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; 1254 1255 n_fs = 1; 1256 spin_lock(&p->fs->lock); 1257 rcu_read_lock(); 1258 for (t = next_thread(p); t != p; t = next_thread(t)) { 1259 if (t->fs == p->fs) 1260 n_fs++; 1261 } 1262 rcu_read_unlock(); 1263 1264 if (p->fs->users > n_fs) { 1265 bprm->unsafe |= LSM_UNSAFE_SHARE; 1266 } else { 1267 res = -EAGAIN; 1268 if (!p->fs->in_exec) { 1269 p->fs->in_exec = 1; 1270 res = 1; 1271 } 1272 } 1273 spin_unlock(&p->fs->lock); 1274 1275 return res; 1276 } 1277 1278 /* 1279 * Fill the binprm structure from the inode. 1280 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes 1281 * 1282 * This may be called multiple times for binary chains (scripts for example). 1283 */ 1284 int prepare_binprm(struct linux_binprm *bprm) 1285 { 1286 umode_t mode; 1287 struct inode * inode = bprm->file->f_path.dentry->d_inode; 1288 int retval; 1289 1290 mode = inode->i_mode; 1291 if (bprm->file->f_op == NULL) 1292 return -EACCES; 1293 1294 /* clear any previous set[ug]id data from a previous binary */ 1295 bprm->cred->euid = current_euid(); 1296 bprm->cred->egid = current_egid(); 1297 1298 if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) && 1299 !current->no_new_privs) { 1300 /* Set-uid? */ 1301 if (mode & S_ISUID) { 1302 if (!kuid_has_mapping(bprm->cred->user_ns, inode->i_uid)) 1303 return -EPERM; 1304 bprm->per_clear |= PER_CLEAR_ON_SETID; 1305 bprm->cred->euid = inode->i_uid; 1306 1307 } 1308 1309 /* Set-gid? */ 1310 /* 1311 * If setgid is set but no group execute bit then this 1312 * is a candidate for mandatory locking, not a setgid 1313 * executable. 1314 */ 1315 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { 1316 if (!kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) 1317 return -EPERM; 1318 bprm->per_clear |= PER_CLEAR_ON_SETID; 1319 bprm->cred->egid = inode->i_gid; 1320 } 1321 } 1322 1323 /* fill in binprm security blob */ 1324 retval = security_bprm_set_creds(bprm); 1325 if (retval) 1326 return retval; 1327 bprm->cred_prepared = 1; 1328 1329 memset(bprm->buf, 0, BINPRM_BUF_SIZE); 1330 return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); 1331 } 1332 1333 EXPORT_SYMBOL(prepare_binprm); 1334 1335 /* 1336 * Arguments are '\0' separated strings found at the location bprm->p 1337 * points to; chop off the first by relocating brpm->p to right after 1338 * the first '\0' encountered. 1339 */ 1340 int remove_arg_zero(struct linux_binprm *bprm) 1341 { 1342 int ret = 0; 1343 unsigned long offset; 1344 char *kaddr; 1345 struct page *page; 1346 1347 if (!bprm->argc) 1348 return 0; 1349 1350 do { 1351 offset = bprm->p & ~PAGE_MASK; 1352 page = get_arg_page(bprm, bprm->p, 0); 1353 if (!page) { 1354 ret = -EFAULT; 1355 goto out; 1356 } 1357 kaddr = kmap_atomic(page); 1358 1359 for (; offset < PAGE_SIZE && kaddr[offset]; 1360 offset++, bprm->p++) 1361 ; 1362 1363 kunmap_atomic(kaddr); 1364 put_arg_page(page); 1365 1366 if (offset == PAGE_SIZE) 1367 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); 1368 } while (offset == PAGE_SIZE); 1369 1370 bprm->p++; 1371 bprm->argc--; 1372 ret = 0; 1373 1374 out: 1375 return ret; 1376 } 1377 EXPORT_SYMBOL(remove_arg_zero); 1378 1379 /* 1380 * cycle the list of binary formats handler, until one recognizes the image 1381 */ 1382 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 1383 { 1384 unsigned int depth = bprm->recursion_depth; 1385 int try,retval; 1386 struct linux_binfmt *fmt; 1387 pid_t old_pid, old_vpid; 1388 1389 retval = security_bprm_check(bprm); 1390 if (retval) 1391 return retval; 1392 1393 retval = audit_bprm(bprm); 1394 if (retval) 1395 return retval; 1396 1397 /* Need to fetch pid before load_binary changes it */ 1398 old_pid = current->pid; 1399 rcu_read_lock(); 1400 old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); 1401 rcu_read_unlock(); 1402 1403 retval = -ENOENT; 1404 for (try=0; try<2; try++) { 1405 read_lock(&binfmt_lock); 1406 list_for_each_entry(fmt, &formats, lh) { 1407 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; 1408 if (!fn) 1409 continue; 1410 if (!try_module_get(fmt->module)) 1411 continue; 1412 read_unlock(&binfmt_lock); 1413 retval = fn(bprm, regs); 1414 /* 1415 * Restore the depth counter to its starting value 1416 * in this call, so we don't have to rely on every 1417 * load_binary function to restore it on return. 1418 */ 1419 bprm->recursion_depth = depth; 1420 if (retval >= 0) { 1421 if (depth == 0) { 1422 trace_sched_process_exec(current, old_pid, bprm); 1423 ptrace_event(PTRACE_EVENT_EXEC, old_vpid); 1424 } 1425 put_binfmt(fmt); 1426 allow_write_access(bprm->file); 1427 if (bprm->file) 1428 fput(bprm->file); 1429 bprm->file = NULL; 1430 current->did_exec = 1; 1431 proc_exec_connector(current); 1432 return retval; 1433 } 1434 read_lock(&binfmt_lock); 1435 put_binfmt(fmt); 1436 if (retval != -ENOEXEC || bprm->mm == NULL) 1437 break; 1438 if (!bprm->file) { 1439 read_unlock(&binfmt_lock); 1440 return retval; 1441 } 1442 } 1443 read_unlock(&binfmt_lock); 1444 #ifdef CONFIG_MODULES 1445 if (retval != -ENOEXEC || bprm->mm == NULL) { 1446 break; 1447 } else { 1448 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) 1449 if (printable(bprm->buf[0]) && 1450 printable(bprm->buf[1]) && 1451 printable(bprm->buf[2]) && 1452 printable(bprm->buf[3])) 1453 break; /* -ENOEXEC */ 1454 if (try) 1455 break; /* -ENOEXEC */ 1456 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); 1457 } 1458 #else 1459 break; 1460 #endif 1461 } 1462 return retval; 1463 } 1464 1465 EXPORT_SYMBOL(search_binary_handler); 1466 1467 /* 1468 * sys_execve() executes a new program. 1469 */ 1470 static int do_execve_common(const char *filename, 1471 struct user_arg_ptr argv, 1472 struct user_arg_ptr envp, 1473 struct pt_regs *regs) 1474 { 1475 struct linux_binprm *bprm; 1476 struct file *file; 1477 struct files_struct *displaced; 1478 bool clear_in_exec; 1479 int retval; 1480 const struct cred *cred = current_cred(); 1481 1482 /* 1483 * We move the actual failure in case of RLIMIT_NPROC excess from 1484 * set*uid() to execve() because too many poorly written programs 1485 * don't check setuid() return code. Here we additionally recheck 1486 * whether NPROC limit is still exceeded. 1487 */ 1488 if ((current->flags & PF_NPROC_EXCEEDED) && 1489 atomic_read(&cred->user->processes) > rlimit(RLIMIT_NPROC)) { 1490 retval = -EAGAIN; 1491 goto out_ret; 1492 } 1493 1494 /* We're below the limit (still or again), so we don't want to make 1495 * further execve() calls fail. */ 1496 current->flags &= ~PF_NPROC_EXCEEDED; 1497 1498 retval = unshare_files(&displaced); 1499 if (retval) 1500 goto out_ret; 1501 1502 retval = -ENOMEM; 1503 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); 1504 if (!bprm) 1505 goto out_files; 1506 1507 retval = prepare_bprm_creds(bprm); 1508 if (retval) 1509 goto out_free; 1510 1511 retval = check_unsafe_exec(bprm); 1512 if (retval < 0) 1513 goto out_free; 1514 clear_in_exec = retval; 1515 current->in_execve = 1; 1516 1517 file = open_exec(filename); 1518 retval = PTR_ERR(file); 1519 if (IS_ERR(file)) 1520 goto out_unmark; 1521 1522 sched_exec(); 1523 1524 bprm->file = file; 1525 bprm->filename = filename; 1526 bprm->interp = filename; 1527 1528 retval = bprm_mm_init(bprm); 1529 if (retval) 1530 goto out_file; 1531 1532 bprm->argc = count(argv, MAX_ARG_STRINGS); 1533 if ((retval = bprm->argc) < 0) 1534 goto out; 1535 1536 bprm->envc = count(envp, MAX_ARG_STRINGS); 1537 if ((retval = bprm->envc) < 0) 1538 goto out; 1539 1540 retval = prepare_binprm(bprm); 1541 if (retval < 0) 1542 goto out; 1543 1544 retval = copy_strings_kernel(1, &bprm->filename, bprm); 1545 if (retval < 0) 1546 goto out; 1547 1548 bprm->exec = bprm->p; 1549 retval = copy_strings(bprm->envc, envp, bprm); 1550 if (retval < 0) 1551 goto out; 1552 1553 retval = copy_strings(bprm->argc, argv, bprm); 1554 if (retval < 0) 1555 goto out; 1556 1557 retval = search_binary_handler(bprm,regs); 1558 if (retval < 0) 1559 goto out; 1560 1561 /* execve succeeded */ 1562 current->fs->in_exec = 0; 1563 current->in_execve = 0; 1564 acct_update_integrals(current); 1565 free_bprm(bprm); 1566 if (displaced) 1567 put_files_struct(displaced); 1568 return retval; 1569 1570 out: 1571 if (bprm->mm) { 1572 acct_arg_size(bprm, 0); 1573 mmput(bprm->mm); 1574 } 1575 1576 out_file: 1577 if (bprm->file) { 1578 allow_write_access(bprm->file); 1579 fput(bprm->file); 1580 } 1581 1582 out_unmark: 1583 if (clear_in_exec) 1584 current->fs->in_exec = 0; 1585 current->in_execve = 0; 1586 1587 out_free: 1588 free_bprm(bprm); 1589 1590 out_files: 1591 if (displaced) 1592 reset_files_struct(displaced); 1593 out_ret: 1594 return retval; 1595 } 1596 1597 int do_execve(const char *filename, 1598 const char __user *const __user *__argv, 1599 const char __user *const __user *__envp, 1600 struct pt_regs *regs) 1601 { 1602 struct user_arg_ptr argv = { .ptr.native = __argv }; 1603 struct user_arg_ptr envp = { .ptr.native = __envp }; 1604 return do_execve_common(filename, argv, envp, regs); 1605 } 1606 1607 #ifdef CONFIG_COMPAT 1608 int compat_do_execve(char *filename, 1609 compat_uptr_t __user *__argv, 1610 compat_uptr_t __user *__envp, 1611 struct pt_regs *regs) 1612 { 1613 struct user_arg_ptr argv = { 1614 .is_compat = true, 1615 .ptr.compat = __argv, 1616 }; 1617 struct user_arg_ptr envp = { 1618 .is_compat = true, 1619 .ptr.compat = __envp, 1620 }; 1621 return do_execve_common(filename, argv, envp, regs); 1622 } 1623 #endif 1624 1625 void set_binfmt(struct linux_binfmt *new) 1626 { 1627 struct mm_struct *mm = current->mm; 1628 1629 if (mm->binfmt) 1630 module_put(mm->binfmt->module); 1631 1632 mm->binfmt = new; 1633 if (new) 1634 __module_get(new->module); 1635 } 1636 1637 EXPORT_SYMBOL(set_binfmt); 1638 1639 static int expand_corename(struct core_name *cn) 1640 { 1641 char *old_corename = cn->corename; 1642 1643 cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); 1644 cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL); 1645 1646 if (!cn->corename) { 1647 kfree(old_corename); 1648 return -ENOMEM; 1649 } 1650 1651 return 0; 1652 } 1653 1654 static int cn_printf(struct core_name *cn, const char *fmt, ...) 1655 { 1656 char *cur; 1657 int need; 1658 int ret; 1659 va_list arg; 1660 1661 va_start(arg, fmt); 1662 need = vsnprintf(NULL, 0, fmt, arg); 1663 va_end(arg); 1664 1665 if (likely(need < cn->size - cn->used - 1)) 1666 goto out_printf; 1667 1668 ret = expand_corename(cn); 1669 if (ret) 1670 goto expand_fail; 1671 1672 out_printf: 1673 cur = cn->corename + cn->used; 1674 va_start(arg, fmt); 1675 vsnprintf(cur, need + 1, fmt, arg); 1676 va_end(arg); 1677 cn->used += need; 1678 return 0; 1679 1680 expand_fail: 1681 return ret; 1682 } 1683 1684 static void cn_escape(char *str) 1685 { 1686 for (; *str; str++) 1687 if (*str == '/') 1688 *str = '!'; 1689 } 1690 1691 static int cn_print_exe_file(struct core_name *cn) 1692 { 1693 struct file *exe_file; 1694 char *pathbuf, *path; 1695 int ret; 1696 1697 exe_file = get_mm_exe_file(current->mm); 1698 if (!exe_file) { 1699 char *commstart = cn->corename + cn->used; 1700 ret = cn_printf(cn, "%s (path unknown)", current->comm); 1701 cn_escape(commstart); 1702 return ret; 1703 } 1704 1705 pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); 1706 if (!pathbuf) { 1707 ret = -ENOMEM; 1708 goto put_exe_file; 1709 } 1710 1711 path = d_path(&exe_file->f_path, pathbuf, PATH_MAX); 1712 if (IS_ERR(path)) { 1713 ret = PTR_ERR(path); 1714 goto free_buf; 1715 } 1716 1717 cn_escape(path); 1718 1719 ret = cn_printf(cn, "%s", path); 1720 1721 free_buf: 1722 kfree(pathbuf); 1723 put_exe_file: 1724 fput(exe_file); 1725 return ret; 1726 } 1727 1728 /* format_corename will inspect the pattern parameter, and output a 1729 * name into corename, which must have space for at least 1730 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. 1731 */ 1732 static int format_corename(struct core_name *cn, long signr) 1733 { 1734 const struct cred *cred = current_cred(); 1735 const char *pat_ptr = core_pattern; 1736 int ispipe = (*pat_ptr == '|'); 1737 int pid_in_pattern = 0; 1738 int err = 0; 1739 1740 cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); 1741 cn->corename = kmalloc(cn->size, GFP_KERNEL); 1742 cn->used = 0; 1743 1744 if (!cn->corename) 1745 return -ENOMEM; 1746 1747 /* Repeat as long as we have more pattern to process and more output 1748 space */ 1749 while (*pat_ptr) { 1750 if (*pat_ptr != '%') { 1751 if (*pat_ptr == 0) 1752 goto out; 1753 err = cn_printf(cn, "%c", *pat_ptr++); 1754 } else { 1755 switch (*++pat_ptr) { 1756 /* single % at the end, drop that */ 1757 case 0: 1758 goto out; 1759 /* Double percent, output one percent */ 1760 case '%': 1761 err = cn_printf(cn, "%c", '%'); 1762 break; 1763 /* pid */ 1764 case 'p': 1765 pid_in_pattern = 1; 1766 err = cn_printf(cn, "%d", 1767 task_tgid_vnr(current)); 1768 break; 1769 /* uid */ 1770 case 'u': 1771 err = cn_printf(cn, "%d", cred->uid); 1772 break; 1773 /* gid */ 1774 case 'g': 1775 err = cn_printf(cn, "%d", cred->gid); 1776 break; 1777 /* signal that caused the coredump */ 1778 case 's': 1779 err = cn_printf(cn, "%ld", signr); 1780 break; 1781 /* UNIX time of coredump */ 1782 case 't': { 1783 struct timeval tv; 1784 do_gettimeofday(&tv); 1785 err = cn_printf(cn, "%lu", tv.tv_sec); 1786 break; 1787 } 1788 /* hostname */ 1789 case 'h': { 1790 char *namestart = cn->corename + cn->used; 1791 down_read(&uts_sem); 1792 err = cn_printf(cn, "%s", 1793 utsname()->nodename); 1794 up_read(&uts_sem); 1795 cn_escape(namestart); 1796 break; 1797 } 1798 /* executable */ 1799 case 'e': { 1800 char *commstart = cn->corename + cn->used; 1801 err = cn_printf(cn, "%s", current->comm); 1802 cn_escape(commstart); 1803 break; 1804 } 1805 case 'E': 1806 err = cn_print_exe_file(cn); 1807 break; 1808 /* core limit size */ 1809 case 'c': 1810 err = cn_printf(cn, "%lu", 1811 rlimit(RLIMIT_CORE)); 1812 break; 1813 default: 1814 break; 1815 } 1816 ++pat_ptr; 1817 } 1818 1819 if (err) 1820 return err; 1821 } 1822 1823 /* Backward compatibility with core_uses_pid: 1824 * 1825 * If core_pattern does not include a %p (as is the default) 1826 * and core_uses_pid is set, then .%pid will be appended to 1827 * the filename. Do not do this for piped commands. */ 1828 if (!ispipe && !pid_in_pattern && core_uses_pid) { 1829 err = cn_printf(cn, ".%d", task_tgid_vnr(current)); 1830 if (err) 1831 return err; 1832 } 1833 out: 1834 return ispipe; 1835 } 1836 1837 static int zap_process(struct task_struct *start, int exit_code) 1838 { 1839 struct task_struct *t; 1840 int nr = 0; 1841 1842 start->signal->flags = SIGNAL_GROUP_EXIT; 1843 start->signal->group_exit_code = exit_code; 1844 start->signal->group_stop_count = 0; 1845 1846 t = start; 1847 do { 1848 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); 1849 if (t != current && t->mm) { 1850 sigaddset(&t->pending.signal, SIGKILL); 1851 signal_wake_up(t, 1); 1852 nr++; 1853 } 1854 } while_each_thread(start, t); 1855 1856 return nr; 1857 } 1858 1859 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, 1860 struct core_state *core_state, int exit_code) 1861 { 1862 struct task_struct *g, *p; 1863 unsigned long flags; 1864 int nr = -EAGAIN; 1865 1866 spin_lock_irq(&tsk->sighand->siglock); 1867 if (!signal_group_exit(tsk->signal)) { 1868 mm->core_state = core_state; 1869 nr = zap_process(tsk, exit_code); 1870 } 1871 spin_unlock_irq(&tsk->sighand->siglock); 1872 if (unlikely(nr < 0)) 1873 return nr; 1874 1875 if (atomic_read(&mm->mm_users) == nr + 1) 1876 goto done; 1877 /* 1878 * We should find and kill all tasks which use this mm, and we should 1879 * count them correctly into ->nr_threads. We don't take tasklist 1880 * lock, but this is safe wrt: 1881 * 1882 * fork: 1883 * None of sub-threads can fork after zap_process(leader). All 1884 * processes which were created before this point should be 1885 * visible to zap_threads() because copy_process() adds the new 1886 * process to the tail of init_task.tasks list, and lock/unlock 1887 * of ->siglock provides a memory barrier. 1888 * 1889 * do_exit: 1890 * The caller holds mm->mmap_sem. This means that the task which 1891 * uses this mm can't pass exit_mm(), so it can't exit or clear 1892 * its ->mm. 1893 * 1894 * de_thread: 1895 * It does list_replace_rcu(&leader->tasks, ¤t->tasks), 1896 * we must see either old or new leader, this does not matter. 1897 * However, it can change p->sighand, so lock_task_sighand(p) 1898 * must be used. Since p->mm != NULL and we hold ->mmap_sem 1899 * it can't fail. 1900 * 1901 * Note also that "g" can be the old leader with ->mm == NULL 1902 * and already unhashed and thus removed from ->thread_group. 1903 * This is OK, __unhash_process()->list_del_rcu() does not 1904 * clear the ->next pointer, we will find the new leader via 1905 * next_thread(). 1906 */ 1907 rcu_read_lock(); 1908 for_each_process(g) { 1909 if (g == tsk->group_leader) 1910 continue; 1911 if (g->flags & PF_KTHREAD) 1912 continue; 1913 p = g; 1914 do { 1915 if (p->mm) { 1916 if (unlikely(p->mm == mm)) { 1917 lock_task_sighand(p, &flags); 1918 nr += zap_process(p, exit_code); 1919 unlock_task_sighand(p, &flags); 1920 } 1921 break; 1922 } 1923 } while_each_thread(g, p); 1924 } 1925 rcu_read_unlock(); 1926 done: 1927 atomic_set(&core_state->nr_threads, nr); 1928 return nr; 1929 } 1930 1931 static int coredump_wait(int exit_code, struct core_state *core_state) 1932 { 1933 struct task_struct *tsk = current; 1934 struct mm_struct *mm = tsk->mm; 1935 int core_waiters = -EBUSY; 1936 1937 init_completion(&core_state->startup); 1938 core_state->dumper.task = tsk; 1939 core_state->dumper.next = NULL; 1940 1941 down_write(&mm->mmap_sem); 1942 if (!mm->core_state) 1943 core_waiters = zap_threads(tsk, mm, core_state, exit_code); 1944 up_write(&mm->mmap_sem); 1945 1946 if (core_waiters > 0) { 1947 struct core_thread *ptr; 1948 1949 wait_for_completion(&core_state->startup); 1950 /* 1951 * Wait for all the threads to become inactive, so that 1952 * all the thread context (extended register state, like 1953 * fpu etc) gets copied to the memory. 1954 */ 1955 ptr = core_state->dumper.next; 1956 while (ptr != NULL) { 1957 wait_task_inactive(ptr->task, 0); 1958 ptr = ptr->next; 1959 } 1960 } 1961 1962 return core_waiters; 1963 } 1964 1965 static void coredump_finish(struct mm_struct *mm) 1966 { 1967 struct core_thread *curr, *next; 1968 struct task_struct *task; 1969 1970 next = mm->core_state->dumper.next; 1971 while ((curr = next) != NULL) { 1972 next = curr->next; 1973 task = curr->task; 1974 /* 1975 * see exit_mm(), curr->task must not see 1976 * ->task == NULL before we read ->next. 1977 */ 1978 smp_mb(); 1979 curr->task = NULL; 1980 wake_up_process(task); 1981 } 1982 1983 mm->core_state = NULL; 1984 } 1985 1986 /* 1987 * set_dumpable converts traditional three-value dumpable to two flags and 1988 * stores them into mm->flags. It modifies lower two bits of mm->flags, but 1989 * these bits are not changed atomically. So get_dumpable can observe the 1990 * intermediate state. To avoid doing unexpected behavior, get get_dumpable 1991 * return either old dumpable or new one by paying attention to the order of 1992 * modifying the bits. 1993 * 1994 * dumpable | mm->flags (binary) 1995 * old new | initial interim final 1996 * ---------+----------------------- 1997 * 0 1 | 00 01 01 1998 * 0 2 | 00 10(*) 11 1999 * 1 0 | 01 00 00 2000 * 1 2 | 01 11 11 2001 * 2 0 | 11 10(*) 00 2002 * 2 1 | 11 11 01 2003 * 2004 * (*) get_dumpable regards interim value of 10 as 11. 2005 */ 2006 void set_dumpable(struct mm_struct *mm, int value) 2007 { 2008 switch (value) { 2009 case 0: 2010 clear_bit(MMF_DUMPABLE, &mm->flags); 2011 smp_wmb(); 2012 clear_bit(MMF_DUMP_SECURELY, &mm->flags); 2013 break; 2014 case 1: 2015 set_bit(MMF_DUMPABLE, &mm->flags); 2016 smp_wmb(); 2017 clear_bit(MMF_DUMP_SECURELY, &mm->flags); 2018 break; 2019 case 2: 2020 set_bit(MMF_DUMP_SECURELY, &mm->flags); 2021 smp_wmb(); 2022 set_bit(MMF_DUMPABLE, &mm->flags); 2023 break; 2024 } 2025 } 2026 2027 static int __get_dumpable(unsigned long mm_flags) 2028 { 2029 int ret; 2030 2031 ret = mm_flags & MMF_DUMPABLE_MASK; 2032 return (ret >= 2) ? 2 : ret; 2033 } 2034 2035 int get_dumpable(struct mm_struct *mm) 2036 { 2037 return __get_dumpable(mm->flags); 2038 } 2039 2040 static void wait_for_dump_helpers(struct file *file) 2041 { 2042 struct pipe_inode_info *pipe; 2043 2044 pipe = file->f_path.dentry->d_inode->i_pipe; 2045 2046 pipe_lock(pipe); 2047 pipe->readers++; 2048 pipe->writers--; 2049 2050 while ((pipe->readers > 1) && (!signal_pending(current))) { 2051 wake_up_interruptible_sync(&pipe->wait); 2052 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 2053 pipe_wait(pipe); 2054 } 2055 2056 pipe->readers--; 2057 pipe->writers++; 2058 pipe_unlock(pipe); 2059 2060 } 2061 2062 2063 /* 2064 * umh_pipe_setup 2065 * helper function to customize the process used 2066 * to collect the core in userspace. Specifically 2067 * it sets up a pipe and installs it as fd 0 (stdin) 2068 * for the process. Returns 0 on success, or 2069 * PTR_ERR on failure. 2070 * Note that it also sets the core limit to 1. This 2071 * is a special value that we use to trap recursive 2072 * core dumps 2073 */ 2074 static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) 2075 { 2076 struct file *rp, *wp; 2077 struct fdtable *fdt; 2078 struct coredump_params *cp = (struct coredump_params *)info->data; 2079 struct files_struct *cf = current->files; 2080 2081 wp = create_write_pipe(0); 2082 if (IS_ERR(wp)) 2083 return PTR_ERR(wp); 2084 2085 rp = create_read_pipe(wp, 0); 2086 if (IS_ERR(rp)) { 2087 free_write_pipe(wp); 2088 return PTR_ERR(rp); 2089 } 2090 2091 cp->file = wp; 2092 2093 sys_close(0); 2094 fd_install(0, rp); 2095 spin_lock(&cf->file_lock); 2096 fdt = files_fdtable(cf); 2097 __set_open_fd(0, fdt); 2098 __clear_close_on_exec(0, fdt); 2099 spin_unlock(&cf->file_lock); 2100 2101 /* and disallow core files too */ 2102 current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; 2103 2104 return 0; 2105 } 2106 2107 void do_coredump(long signr, int exit_code, struct pt_regs *regs) 2108 { 2109 struct core_state core_state; 2110 struct core_name cn; 2111 struct mm_struct *mm = current->mm; 2112 struct linux_binfmt * binfmt; 2113 const struct cred *old_cred; 2114 struct cred *cred; 2115 int retval = 0; 2116 int flag = 0; 2117 int ispipe; 2118 static atomic_t core_dump_count = ATOMIC_INIT(0); 2119 struct coredump_params cprm = { 2120 .signr = signr, 2121 .regs = regs, 2122 .limit = rlimit(RLIMIT_CORE), 2123 /* 2124 * We must use the same mm->flags while dumping core to avoid 2125 * inconsistency of bit flags, since this flag is not protected 2126 * by any locks. 2127 */ 2128 .mm_flags = mm->flags, 2129 }; 2130 2131 audit_core_dumps(signr); 2132 2133 binfmt = mm->binfmt; 2134 if (!binfmt || !binfmt->core_dump) 2135 goto fail; 2136 if (!__get_dumpable(cprm.mm_flags)) 2137 goto fail; 2138 2139 cred = prepare_creds(); 2140 if (!cred) 2141 goto fail; 2142 /* 2143 * We cannot trust fsuid as being the "true" uid of the 2144 * process nor do we know its entire history. We only know it 2145 * was tainted so we dump it as root in mode 2. 2146 */ 2147 if (__get_dumpable(cprm.mm_flags) == 2) { 2148 /* Setuid core dump mode */ 2149 flag = O_EXCL; /* Stop rewrite attacks */ 2150 cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ 2151 } 2152 2153 retval = coredump_wait(exit_code, &core_state); 2154 if (retval < 0) 2155 goto fail_creds; 2156 2157 old_cred = override_creds(cred); 2158 2159 /* 2160 * Clear any false indication of pending signals that might 2161 * be seen by the filesystem code called to write the core file. 2162 */ 2163 clear_thread_flag(TIF_SIGPENDING); 2164 2165 ispipe = format_corename(&cn, signr); 2166 2167 if (ispipe) { 2168 int dump_count; 2169 char **helper_argv; 2170 2171 if (ispipe < 0) { 2172 printk(KERN_WARNING "format_corename failed\n"); 2173 printk(KERN_WARNING "Aborting core\n"); 2174 goto fail_corename; 2175 } 2176 2177 if (cprm.limit == 1) { 2178 /* 2179 * Normally core limits are irrelevant to pipes, since 2180 * we're not writing to the file system, but we use 2181 * cprm.limit of 1 here as a speacial value. Any 2182 * non-1 limit gets set to RLIM_INFINITY below, but 2183 * a limit of 0 skips the dump. This is a consistent 2184 * way to catch recursive crashes. We can still crash 2185 * if the core_pattern binary sets RLIM_CORE = !1 2186 * but it runs as root, and can do lots of stupid things 2187 * Note that we use task_tgid_vnr here to grab the pid 2188 * of the process group leader. That way we get the 2189 * right pid if a thread in a multi-threaded 2190 * core_pattern process dies. 2191 */ 2192 printk(KERN_WARNING 2193 "Process %d(%s) has RLIMIT_CORE set to 1\n", 2194 task_tgid_vnr(current), current->comm); 2195 printk(KERN_WARNING "Aborting core\n"); 2196 goto fail_unlock; 2197 } 2198 cprm.limit = RLIM_INFINITY; 2199 2200 dump_count = atomic_inc_return(&core_dump_count); 2201 if (core_pipe_limit && (core_pipe_limit < dump_count)) { 2202 printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", 2203 task_tgid_vnr(current), current->comm); 2204 printk(KERN_WARNING "Skipping core dump\n"); 2205 goto fail_dropcount; 2206 } 2207 2208 helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); 2209 if (!helper_argv) { 2210 printk(KERN_WARNING "%s failed to allocate memory\n", 2211 __func__); 2212 goto fail_dropcount; 2213 } 2214 2215 retval = call_usermodehelper_fns(helper_argv[0], helper_argv, 2216 NULL, UMH_WAIT_EXEC, umh_pipe_setup, 2217 NULL, &cprm); 2218 argv_free(helper_argv); 2219 if (retval) { 2220 printk(KERN_INFO "Core dump to %s pipe failed\n", 2221 cn.corename); 2222 goto close_fail; 2223 } 2224 } else { 2225 struct inode *inode; 2226 2227 if (cprm.limit < binfmt->min_coredump) 2228 goto fail_unlock; 2229 2230 cprm.file = filp_open(cn.corename, 2231 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 2232 0600); 2233 if (IS_ERR(cprm.file)) 2234 goto fail_unlock; 2235 2236 inode = cprm.file->f_path.dentry->d_inode; 2237 if (inode->i_nlink > 1) 2238 goto close_fail; 2239 if (d_unhashed(cprm.file->f_path.dentry)) 2240 goto close_fail; 2241 /* 2242 * AK: actually i see no reason to not allow this for named 2243 * pipes etc, but keep the previous behaviour for now. 2244 */ 2245 if (!S_ISREG(inode->i_mode)) 2246 goto close_fail; 2247 /* 2248 * Dont allow local users get cute and trick others to coredump 2249 * into their pre-created files. 2250 */ 2251 if (!uid_eq(inode->i_uid, current_fsuid())) 2252 goto close_fail; 2253 if (!cprm.file->f_op || !cprm.file->f_op->write) 2254 goto close_fail; 2255 if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) 2256 goto close_fail; 2257 } 2258 2259 retval = binfmt->core_dump(&cprm); 2260 if (retval) 2261 current->signal->group_exit_code |= 0x80; 2262 2263 if (ispipe && core_pipe_limit) 2264 wait_for_dump_helpers(cprm.file); 2265 close_fail: 2266 if (cprm.file) 2267 filp_close(cprm.file, NULL); 2268 fail_dropcount: 2269 if (ispipe) 2270 atomic_dec(&core_dump_count); 2271 fail_unlock: 2272 kfree(cn.corename); 2273 fail_corename: 2274 coredump_finish(mm); 2275 revert_creds(old_cred); 2276 fail_creds: 2277 put_cred(cred); 2278 fail: 2279 return; 2280 } 2281 2282 /* 2283 * Core dumping helper functions. These are the only things you should 2284 * do on a core-file: use only these functions to write out all the 2285 * necessary info. 2286 */ 2287 int dump_write(struct file *file, const void *addr, int nr) 2288 { 2289 return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; 2290 } 2291 EXPORT_SYMBOL(dump_write); 2292 2293 int dump_seek(struct file *file, loff_t off) 2294 { 2295 int ret = 1; 2296 2297 if (file->f_op->llseek && file->f_op->llseek != no_llseek) { 2298 if (file->f_op->llseek(file, off, SEEK_CUR) < 0) 2299 return 0; 2300 } else { 2301 char *buf = (char *)get_zeroed_page(GFP_KERNEL); 2302 2303 if (!buf) 2304 return 0; 2305 while (off > 0) { 2306 unsigned long n = off; 2307 2308 if (n > PAGE_SIZE) 2309 n = PAGE_SIZE; 2310 if (!dump_write(file, buf, n)) { 2311 ret = 0; 2312 break; 2313 } 2314 off -= n; 2315 } 2316 free_page((unsigned long)buf); 2317 } 2318 return ret; 2319 } 2320 EXPORT_SYMBOL(dump_seek); 2321