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/vmacache.h> 30 #include <linux/stat.h> 31 #include <linux/fcntl.h> 32 #include <linux/swap.h> 33 #include <linux/string.h> 34 #include <linux/init.h> 35 #include <linux/pagemap.h> 36 #include <linux/perf_event.h> 37 #include <linux/highmem.h> 38 #include <linux/spinlock.h> 39 #include <linux/key.h> 40 #include <linux/personality.h> 41 #include <linux/binfmts.h> 42 #include <linux/utsname.h> 43 #include <linux/pid_namespace.h> 44 #include <linux/module.h> 45 #include <linux/namei.h> 46 #include <linux/mount.h> 47 #include <linux/security.h> 48 #include <linux/syscalls.h> 49 #include <linux/tsacct_kern.h> 50 #include <linux/cn_proc.h> 51 #include <linux/audit.h> 52 #include <linux/tracehook.h> 53 #include <linux/kmod.h> 54 #include <linux/fsnotify.h> 55 #include <linux/fs_struct.h> 56 #include <linux/pipe_fs_i.h> 57 #include <linux/oom.h> 58 #include <linux/compat.h> 59 60 #include <asm/uaccess.h> 61 #include <asm/mmu_context.h> 62 #include <asm/tlb.h> 63 64 #include <trace/events/task.h> 65 #include "internal.h" 66 67 #include <trace/events/sched.h> 68 69 int suid_dumpable = 0; 70 71 static LIST_HEAD(formats); 72 static DEFINE_RWLOCK(binfmt_lock); 73 74 void __register_binfmt(struct linux_binfmt * fmt, int insert) 75 { 76 BUG_ON(!fmt); 77 if (WARN_ON(!fmt->load_binary)) 78 return; 79 write_lock(&binfmt_lock); 80 insert ? list_add(&fmt->lh, &formats) : 81 list_add_tail(&fmt->lh, &formats); 82 write_unlock(&binfmt_lock); 83 } 84 85 EXPORT_SYMBOL(__register_binfmt); 86 87 void unregister_binfmt(struct linux_binfmt * fmt) 88 { 89 write_lock(&binfmt_lock); 90 list_del(&fmt->lh); 91 write_unlock(&binfmt_lock); 92 } 93 94 EXPORT_SYMBOL(unregister_binfmt); 95 96 static inline void put_binfmt(struct linux_binfmt * fmt) 97 { 98 module_put(fmt->module); 99 } 100 101 #ifdef CONFIG_USELIB 102 /* 103 * Note that a shared library must be both readable and executable due to 104 * security reasons. 105 * 106 * Also note that we take the address to load from from the file itself. 107 */ 108 SYSCALL_DEFINE1(uselib, const char __user *, library) 109 { 110 struct linux_binfmt *fmt; 111 struct file *file; 112 struct filename *tmp = getname(library); 113 int error = PTR_ERR(tmp); 114 static const struct open_flags uselib_flags = { 115 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 116 .acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN, 117 .intent = LOOKUP_OPEN, 118 .lookup_flags = LOOKUP_FOLLOW, 119 }; 120 121 if (IS_ERR(tmp)) 122 goto out; 123 124 file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); 125 putname(tmp); 126 error = PTR_ERR(file); 127 if (IS_ERR(file)) 128 goto out; 129 130 error = -EINVAL; 131 if (!S_ISREG(file_inode(file)->i_mode)) 132 goto exit; 133 134 error = -EACCES; 135 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) 136 goto exit; 137 138 fsnotify_open(file); 139 140 error = -ENOEXEC; 141 142 read_lock(&binfmt_lock); 143 list_for_each_entry(fmt, &formats, lh) { 144 if (!fmt->load_shlib) 145 continue; 146 if (!try_module_get(fmt->module)) 147 continue; 148 read_unlock(&binfmt_lock); 149 error = fmt->load_shlib(file); 150 read_lock(&binfmt_lock); 151 put_binfmt(fmt); 152 if (error != -ENOEXEC) 153 break; 154 } 155 read_unlock(&binfmt_lock); 156 exit: 157 fput(file); 158 out: 159 return error; 160 } 161 #endif /* #ifdef CONFIG_USELIB */ 162 163 #ifdef CONFIG_MMU 164 /* 165 * The nascent bprm->mm is not visible until exec_mmap() but it can 166 * use a lot of memory, account these pages in current->mm temporary 167 * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we 168 * change the counter back via acct_arg_size(0). 169 */ 170 static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) 171 { 172 struct mm_struct *mm = current->mm; 173 long diff = (long)(pages - bprm->vma_pages); 174 175 if (!mm || !diff) 176 return; 177 178 bprm->vma_pages = pages; 179 add_mm_counter(mm, MM_ANONPAGES, diff); 180 } 181 182 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, 183 int write) 184 { 185 struct page *page; 186 int ret; 187 188 #ifdef CONFIG_STACK_GROWSUP 189 if (write) { 190 ret = expand_downwards(bprm->vma, pos); 191 if (ret < 0) 192 return NULL; 193 } 194 #endif 195 ret = get_user_pages(current, bprm->mm, pos, 196 1, write, 1, &page, NULL); 197 if (ret <= 0) 198 return NULL; 199 200 if (write) { 201 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; 202 struct rlimit *rlim; 203 204 acct_arg_size(bprm, size / PAGE_SIZE); 205 206 /* 207 * We've historically supported up to 32 pages (ARG_MAX) 208 * of argument strings even with small stacks 209 */ 210 if (size <= ARG_MAX) 211 return page; 212 213 /* 214 * Limit to 1/4-th the stack size for the argv+env strings. 215 * This ensures that: 216 * - the remaining binfmt code will not run out of stack space, 217 * - the program will have a reasonable amount of stack left 218 * to work from. 219 */ 220 rlim = current->signal->rlim; 221 if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { 222 put_page(page); 223 return NULL; 224 } 225 } 226 227 return page; 228 } 229 230 static void put_arg_page(struct page *page) 231 { 232 put_page(page); 233 } 234 235 static void free_arg_page(struct linux_binprm *bprm, int i) 236 { 237 } 238 239 static void free_arg_pages(struct linux_binprm *bprm) 240 { 241 } 242 243 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, 244 struct page *page) 245 { 246 flush_cache_page(bprm->vma, pos, page_to_pfn(page)); 247 } 248 249 static int __bprm_mm_init(struct linux_binprm *bprm) 250 { 251 int err; 252 struct vm_area_struct *vma = NULL; 253 struct mm_struct *mm = bprm->mm; 254 255 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 256 if (!vma) 257 return -ENOMEM; 258 259 down_write(&mm->mmap_sem); 260 vma->vm_mm = mm; 261 262 /* 263 * Place the stack at the largest stack address the architecture 264 * supports. Later, we'll move this to an appropriate place. We don't 265 * use STACK_TOP because that can depend on attributes which aren't 266 * configured yet. 267 */ 268 BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); 269 vma->vm_end = STACK_TOP_MAX; 270 vma->vm_start = vma->vm_end - PAGE_SIZE; 271 vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; 272 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 273 INIT_LIST_HEAD(&vma->anon_vma_chain); 274 275 err = insert_vm_struct(mm, vma); 276 if (err) 277 goto err; 278 279 mm->stack_vm = mm->total_vm = 1; 280 up_write(&mm->mmap_sem); 281 bprm->p = vma->vm_end - sizeof(void *); 282 return 0; 283 err: 284 up_write(&mm->mmap_sem); 285 bprm->vma = NULL; 286 kmem_cache_free(vm_area_cachep, vma); 287 return err; 288 } 289 290 static bool valid_arg_len(struct linux_binprm *bprm, long len) 291 { 292 return len <= MAX_ARG_STRLEN; 293 } 294 295 #else 296 297 static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) 298 { 299 } 300 301 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, 302 int write) 303 { 304 struct page *page; 305 306 page = bprm->page[pos / PAGE_SIZE]; 307 if (!page && write) { 308 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); 309 if (!page) 310 return NULL; 311 bprm->page[pos / PAGE_SIZE] = page; 312 } 313 314 return page; 315 } 316 317 static void put_arg_page(struct page *page) 318 { 319 } 320 321 static void free_arg_page(struct linux_binprm *bprm, int i) 322 { 323 if (bprm->page[i]) { 324 __free_page(bprm->page[i]); 325 bprm->page[i] = NULL; 326 } 327 } 328 329 static void free_arg_pages(struct linux_binprm *bprm) 330 { 331 int i; 332 333 for (i = 0; i < MAX_ARG_PAGES; i++) 334 free_arg_page(bprm, i); 335 } 336 337 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, 338 struct page *page) 339 { 340 } 341 342 static int __bprm_mm_init(struct linux_binprm *bprm) 343 { 344 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); 345 return 0; 346 } 347 348 static bool valid_arg_len(struct linux_binprm *bprm, long len) 349 { 350 return len <= bprm->p; 351 } 352 353 #endif /* CONFIG_MMU */ 354 355 /* 356 * Create a new mm_struct and populate it with a temporary stack 357 * vm_area_struct. We don't have enough context at this point to set the stack 358 * flags, permissions, and offset, so we use temporary values. We'll update 359 * them later in setup_arg_pages(). 360 */ 361 static int bprm_mm_init(struct linux_binprm *bprm) 362 { 363 int err; 364 struct mm_struct *mm = NULL; 365 366 bprm->mm = mm = mm_alloc(); 367 err = -ENOMEM; 368 if (!mm) 369 goto err; 370 371 err = __bprm_mm_init(bprm); 372 if (err) 373 goto err; 374 375 return 0; 376 377 err: 378 if (mm) { 379 bprm->mm = NULL; 380 mmdrop(mm); 381 } 382 383 return err; 384 } 385 386 struct user_arg_ptr { 387 #ifdef CONFIG_COMPAT 388 bool is_compat; 389 #endif 390 union { 391 const char __user *const __user *native; 392 #ifdef CONFIG_COMPAT 393 const compat_uptr_t __user *compat; 394 #endif 395 } ptr; 396 }; 397 398 static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) 399 { 400 const char __user *native; 401 402 #ifdef CONFIG_COMPAT 403 if (unlikely(argv.is_compat)) { 404 compat_uptr_t compat; 405 406 if (get_user(compat, argv.ptr.compat + nr)) 407 return ERR_PTR(-EFAULT); 408 409 return compat_ptr(compat); 410 } 411 #endif 412 413 if (get_user(native, argv.ptr.native + nr)) 414 return ERR_PTR(-EFAULT); 415 416 return native; 417 } 418 419 /* 420 * count() counts the number of strings in array ARGV. 421 */ 422 static int count(struct user_arg_ptr argv, int max) 423 { 424 int i = 0; 425 426 if (argv.ptr.native != NULL) { 427 for (;;) { 428 const char __user *p = get_user_arg_ptr(argv, i); 429 430 if (!p) 431 break; 432 433 if (IS_ERR(p)) 434 return -EFAULT; 435 436 if (i >= max) 437 return -E2BIG; 438 ++i; 439 440 if (fatal_signal_pending(current)) 441 return -ERESTARTNOHAND; 442 cond_resched(); 443 } 444 } 445 return i; 446 } 447 448 /* 449 * 'copy_strings()' copies argument/environment strings from the old 450 * processes's memory to the new process's stack. The call to get_user_pages() 451 * ensures the destination page is created and not swapped out. 452 */ 453 static int copy_strings(int argc, struct user_arg_ptr argv, 454 struct linux_binprm *bprm) 455 { 456 struct page *kmapped_page = NULL; 457 char *kaddr = NULL; 458 unsigned long kpos = 0; 459 int ret; 460 461 while (argc-- > 0) { 462 const char __user *str; 463 int len; 464 unsigned long pos; 465 466 ret = -EFAULT; 467 str = get_user_arg_ptr(argv, argc); 468 if (IS_ERR(str)) 469 goto out; 470 471 len = strnlen_user(str, MAX_ARG_STRLEN); 472 if (!len) 473 goto out; 474 475 ret = -E2BIG; 476 if (!valid_arg_len(bprm, len)) 477 goto out; 478 479 /* We're going to work our way backwords. */ 480 pos = bprm->p; 481 str += len; 482 bprm->p -= len; 483 484 while (len > 0) { 485 int offset, bytes_to_copy; 486 487 if (fatal_signal_pending(current)) { 488 ret = -ERESTARTNOHAND; 489 goto out; 490 } 491 cond_resched(); 492 493 offset = pos % PAGE_SIZE; 494 if (offset == 0) 495 offset = PAGE_SIZE; 496 497 bytes_to_copy = offset; 498 if (bytes_to_copy > len) 499 bytes_to_copy = len; 500 501 offset -= bytes_to_copy; 502 pos -= bytes_to_copy; 503 str -= bytes_to_copy; 504 len -= bytes_to_copy; 505 506 if (!kmapped_page || kpos != (pos & PAGE_MASK)) { 507 struct page *page; 508 509 page = get_arg_page(bprm, pos, 1); 510 if (!page) { 511 ret = -E2BIG; 512 goto out; 513 } 514 515 if (kmapped_page) { 516 flush_kernel_dcache_page(kmapped_page); 517 kunmap(kmapped_page); 518 put_arg_page(kmapped_page); 519 } 520 kmapped_page = page; 521 kaddr = kmap(kmapped_page); 522 kpos = pos & PAGE_MASK; 523 flush_arg_page(bprm, kpos, kmapped_page); 524 } 525 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { 526 ret = -EFAULT; 527 goto out; 528 } 529 } 530 } 531 ret = 0; 532 out: 533 if (kmapped_page) { 534 flush_kernel_dcache_page(kmapped_page); 535 kunmap(kmapped_page); 536 put_arg_page(kmapped_page); 537 } 538 return ret; 539 } 540 541 /* 542 * Like copy_strings, but get argv and its values from kernel memory. 543 */ 544 int copy_strings_kernel(int argc, const char *const *__argv, 545 struct linux_binprm *bprm) 546 { 547 int r; 548 mm_segment_t oldfs = get_fs(); 549 struct user_arg_ptr argv = { 550 .ptr.native = (const char __user *const __user *)__argv, 551 }; 552 553 set_fs(KERNEL_DS); 554 r = copy_strings(argc, argv, bprm); 555 set_fs(oldfs); 556 557 return r; 558 } 559 EXPORT_SYMBOL(copy_strings_kernel); 560 561 #ifdef CONFIG_MMU 562 563 /* 564 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once 565 * the binfmt code determines where the new stack should reside, we shift it to 566 * its final location. The process proceeds as follows: 567 * 568 * 1) Use shift to calculate the new vma endpoints. 569 * 2) Extend vma to cover both the old and new ranges. This ensures the 570 * arguments passed to subsequent functions are consistent. 571 * 3) Move vma's page tables to the new range. 572 * 4) Free up any cleared pgd range. 573 * 5) Shrink the vma to cover only the new range. 574 */ 575 static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) 576 { 577 struct mm_struct *mm = vma->vm_mm; 578 unsigned long old_start = vma->vm_start; 579 unsigned long old_end = vma->vm_end; 580 unsigned long length = old_end - old_start; 581 unsigned long new_start = old_start - shift; 582 unsigned long new_end = old_end - shift; 583 struct mmu_gather tlb; 584 585 BUG_ON(new_start > new_end); 586 587 /* 588 * ensure there are no vmas between where we want to go 589 * and where we are 590 */ 591 if (vma != find_vma(mm, new_start)) 592 return -EFAULT; 593 594 /* 595 * cover the whole range: [new_start, old_end) 596 */ 597 if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) 598 return -ENOMEM; 599 600 /* 601 * move the page tables downwards, on failure we rely on 602 * process cleanup to remove whatever mess we made. 603 */ 604 if (length != move_page_tables(vma, old_start, 605 vma, new_start, length, false)) 606 return -ENOMEM; 607 608 lru_add_drain(); 609 tlb_gather_mmu(&tlb, mm, old_start, old_end); 610 if (new_end > old_start) { 611 /* 612 * when the old and new regions overlap clear from new_end. 613 */ 614 free_pgd_range(&tlb, new_end, old_end, new_end, 615 vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); 616 } else { 617 /* 618 * otherwise, clean from old_start; this is done to not touch 619 * the address space in [new_end, old_start) some architectures 620 * have constraints on va-space that make this illegal (IA64) - 621 * for the others its just a little faster. 622 */ 623 free_pgd_range(&tlb, old_start, old_end, new_end, 624 vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); 625 } 626 tlb_finish_mmu(&tlb, old_start, old_end); 627 628 /* 629 * Shrink the vma to just the new range. Always succeeds. 630 */ 631 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); 632 633 return 0; 634 } 635 636 /* 637 * Finalizes the stack vm_area_struct. The flags and permissions are updated, 638 * the stack is optionally relocated, and some extra space is added. 639 */ 640 int setup_arg_pages(struct linux_binprm *bprm, 641 unsigned long stack_top, 642 int executable_stack) 643 { 644 unsigned long ret; 645 unsigned long stack_shift; 646 struct mm_struct *mm = current->mm; 647 struct vm_area_struct *vma = bprm->vma; 648 struct vm_area_struct *prev = NULL; 649 unsigned long vm_flags; 650 unsigned long stack_base; 651 unsigned long stack_size; 652 unsigned long stack_expand; 653 unsigned long rlim_stack; 654 655 #ifdef CONFIG_STACK_GROWSUP 656 /* Limit stack size */ 657 stack_base = rlimit_max(RLIMIT_STACK); 658 if (stack_base > STACK_SIZE_MAX) 659 stack_base = STACK_SIZE_MAX; 660 661 /* Make sure we didn't let the argument array grow too large. */ 662 if (vma->vm_end - vma->vm_start > stack_base) 663 return -ENOMEM; 664 665 stack_base = PAGE_ALIGN(stack_top - stack_base); 666 667 stack_shift = vma->vm_start - stack_base; 668 mm->arg_start = bprm->p - stack_shift; 669 bprm->p = vma->vm_end - stack_shift; 670 #else 671 stack_top = arch_align_stack(stack_top); 672 stack_top = PAGE_ALIGN(stack_top); 673 674 if (unlikely(stack_top < mmap_min_addr) || 675 unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) 676 return -ENOMEM; 677 678 stack_shift = vma->vm_end - stack_top; 679 680 bprm->p -= stack_shift; 681 mm->arg_start = bprm->p; 682 #endif 683 684 if (bprm->loader) 685 bprm->loader -= stack_shift; 686 bprm->exec -= stack_shift; 687 688 down_write(&mm->mmap_sem); 689 vm_flags = VM_STACK_FLAGS; 690 691 /* 692 * Adjust stack execute permissions; explicitly enable for 693 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone 694 * (arch default) otherwise. 695 */ 696 if (unlikely(executable_stack == EXSTACK_ENABLE_X)) 697 vm_flags |= VM_EXEC; 698 else if (executable_stack == EXSTACK_DISABLE_X) 699 vm_flags &= ~VM_EXEC; 700 vm_flags |= mm->def_flags; 701 vm_flags |= VM_STACK_INCOMPLETE_SETUP; 702 703 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, 704 vm_flags); 705 if (ret) 706 goto out_unlock; 707 BUG_ON(prev != vma); 708 709 /* Move stack pages down in memory. */ 710 if (stack_shift) { 711 ret = shift_arg_pages(vma, stack_shift); 712 if (ret) 713 goto out_unlock; 714 } 715 716 /* mprotect_fixup is overkill to remove the temporary stack flags */ 717 vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; 718 719 stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ 720 stack_size = vma->vm_end - vma->vm_start; 721 /* 722 * Align this down to a page boundary as expand_stack 723 * will align it up. 724 */ 725 rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; 726 #ifdef CONFIG_STACK_GROWSUP 727 if (stack_size + stack_expand > rlim_stack) 728 stack_base = vma->vm_start + rlim_stack; 729 else 730 stack_base = vma->vm_end + stack_expand; 731 #else 732 if (stack_size + stack_expand > rlim_stack) 733 stack_base = vma->vm_end - rlim_stack; 734 else 735 stack_base = vma->vm_start - stack_expand; 736 #endif 737 current->mm->start_stack = bprm->p; 738 ret = expand_stack(vma, stack_base); 739 if (ret) 740 ret = -EFAULT; 741 742 out_unlock: 743 up_write(&mm->mmap_sem); 744 return ret; 745 } 746 EXPORT_SYMBOL(setup_arg_pages); 747 748 #endif /* CONFIG_MMU */ 749 750 static struct file *do_open_exec(struct filename *name) 751 { 752 struct file *file; 753 int err; 754 static const struct open_flags open_exec_flags = { 755 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 756 .acc_mode = MAY_EXEC | MAY_OPEN, 757 .intent = LOOKUP_OPEN, 758 .lookup_flags = LOOKUP_FOLLOW, 759 }; 760 761 file = do_filp_open(AT_FDCWD, name, &open_exec_flags); 762 if (IS_ERR(file)) 763 goto out; 764 765 err = -EACCES; 766 if (!S_ISREG(file_inode(file)->i_mode)) 767 goto exit; 768 769 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) 770 goto exit; 771 772 fsnotify_open(file); 773 774 err = deny_write_access(file); 775 if (err) 776 goto exit; 777 778 out: 779 return file; 780 781 exit: 782 fput(file); 783 return ERR_PTR(err); 784 } 785 786 struct file *open_exec(const char *name) 787 { 788 struct filename tmp = { .name = name }; 789 return do_open_exec(&tmp); 790 } 791 EXPORT_SYMBOL(open_exec); 792 793 int kernel_read(struct file *file, loff_t offset, 794 char *addr, unsigned long count) 795 { 796 mm_segment_t old_fs; 797 loff_t pos = offset; 798 int result; 799 800 old_fs = get_fs(); 801 set_fs(get_ds()); 802 /* The cast to a user pointer is valid due to the set_fs() */ 803 result = vfs_read(file, (void __user *)addr, count, &pos); 804 set_fs(old_fs); 805 return result; 806 } 807 808 EXPORT_SYMBOL(kernel_read); 809 810 ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) 811 { 812 ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); 813 if (res > 0) 814 flush_icache_range(addr, addr + len); 815 return res; 816 } 817 EXPORT_SYMBOL(read_code); 818 819 static int exec_mmap(struct mm_struct *mm) 820 { 821 struct task_struct *tsk; 822 struct mm_struct *old_mm, *active_mm; 823 824 /* Notify parent that we're no longer interested in the old VM */ 825 tsk = current; 826 old_mm = current->mm; 827 mm_release(tsk, old_mm); 828 829 if (old_mm) { 830 sync_mm_rss(old_mm); 831 /* 832 * Make sure that if there is a core dump in progress 833 * for the old mm, we get out and die instead of going 834 * through with the exec. We must hold mmap_sem around 835 * checking core_state and changing tsk->mm. 836 */ 837 down_read(&old_mm->mmap_sem); 838 if (unlikely(old_mm->core_state)) { 839 up_read(&old_mm->mmap_sem); 840 return -EINTR; 841 } 842 } 843 task_lock(tsk); 844 active_mm = tsk->active_mm; 845 tsk->mm = mm; 846 tsk->active_mm = mm; 847 activate_mm(active_mm, mm); 848 tsk->mm->vmacache_seqnum = 0; 849 vmacache_flush(tsk); 850 task_unlock(tsk); 851 if (old_mm) { 852 up_read(&old_mm->mmap_sem); 853 BUG_ON(active_mm != old_mm); 854 setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); 855 mm_update_next_owner(old_mm); 856 mmput(old_mm); 857 return 0; 858 } 859 mmdrop(active_mm); 860 return 0; 861 } 862 863 /* 864 * This function makes sure the current process has its own signal table, 865 * so that flush_signal_handlers can later reset the handlers without 866 * disturbing other processes. (Other processes might share the signal 867 * table via the CLONE_SIGHAND option to clone().) 868 */ 869 static int de_thread(struct task_struct *tsk) 870 { 871 struct signal_struct *sig = tsk->signal; 872 struct sighand_struct *oldsighand = tsk->sighand; 873 spinlock_t *lock = &oldsighand->siglock; 874 875 if (thread_group_empty(tsk)) 876 goto no_thread_group; 877 878 /* 879 * Kill all other threads in the thread group. 880 */ 881 spin_lock_irq(lock); 882 if (signal_group_exit(sig)) { 883 /* 884 * Another group action in progress, just 885 * return so that the signal is processed. 886 */ 887 spin_unlock_irq(lock); 888 return -EAGAIN; 889 } 890 891 sig->group_exit_task = tsk; 892 sig->notify_count = zap_other_threads(tsk); 893 if (!thread_group_leader(tsk)) 894 sig->notify_count--; 895 896 while (sig->notify_count) { 897 __set_current_state(TASK_KILLABLE); 898 spin_unlock_irq(lock); 899 schedule(); 900 if (unlikely(__fatal_signal_pending(tsk))) 901 goto killed; 902 spin_lock_irq(lock); 903 } 904 spin_unlock_irq(lock); 905 906 /* 907 * At this point all other threads have exited, all we have to 908 * do is to wait for the thread group leader to become inactive, 909 * and to assume its PID: 910 */ 911 if (!thread_group_leader(tsk)) { 912 struct task_struct *leader = tsk->group_leader; 913 914 sig->notify_count = -1; /* for exit_notify() */ 915 for (;;) { 916 threadgroup_change_begin(tsk); 917 write_lock_irq(&tasklist_lock); 918 if (likely(leader->exit_state)) 919 break; 920 __set_current_state(TASK_KILLABLE); 921 write_unlock_irq(&tasklist_lock); 922 threadgroup_change_end(tsk); 923 schedule(); 924 if (unlikely(__fatal_signal_pending(tsk))) 925 goto killed; 926 } 927 928 /* 929 * The only record we have of the real-time age of a 930 * process, regardless of execs it's done, is start_time. 931 * All the past CPU time is accumulated in signal_struct 932 * from sister threads now dead. But in this non-leader 933 * exec, nothing survives from the original leader thread, 934 * whose birth marks the true age of this process now. 935 * When we take on its identity by switching to its PID, we 936 * also take its birthdate (always earlier than our own). 937 */ 938 tsk->start_time = leader->start_time; 939 tsk->real_start_time = leader->real_start_time; 940 941 BUG_ON(!same_thread_group(leader, tsk)); 942 BUG_ON(has_group_leader_pid(tsk)); 943 /* 944 * An exec() starts a new thread group with the 945 * TGID of the previous thread group. Rehash the 946 * two threads with a switched PID, and release 947 * the former thread group leader: 948 */ 949 950 /* Become a process group leader with the old leader's pid. 951 * The old leader becomes a thread of the this thread group. 952 * Note: The old leader also uses this pid until release_task 953 * is called. Odd but simple and correct. 954 */ 955 tsk->pid = leader->pid; 956 change_pid(tsk, PIDTYPE_PID, task_pid(leader)); 957 transfer_pid(leader, tsk, PIDTYPE_PGID); 958 transfer_pid(leader, tsk, PIDTYPE_SID); 959 960 list_replace_rcu(&leader->tasks, &tsk->tasks); 961 list_replace_init(&leader->sibling, &tsk->sibling); 962 963 tsk->group_leader = tsk; 964 leader->group_leader = tsk; 965 966 tsk->exit_signal = SIGCHLD; 967 leader->exit_signal = -1; 968 969 BUG_ON(leader->exit_state != EXIT_ZOMBIE); 970 leader->exit_state = EXIT_DEAD; 971 972 /* 973 * We are going to release_task()->ptrace_unlink() silently, 974 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees 975 * the tracer wont't block again waiting for this thread. 976 */ 977 if (unlikely(leader->ptrace)) 978 __wake_up_parent(leader, leader->parent); 979 write_unlock_irq(&tasklist_lock); 980 threadgroup_change_end(tsk); 981 982 release_task(leader); 983 } 984 985 sig->group_exit_task = NULL; 986 sig->notify_count = 0; 987 988 no_thread_group: 989 /* we have changed execution domain */ 990 tsk->exit_signal = SIGCHLD; 991 992 exit_itimers(sig); 993 flush_itimer_signals(); 994 995 if (atomic_read(&oldsighand->count) != 1) { 996 struct sighand_struct *newsighand; 997 /* 998 * This ->sighand is shared with the CLONE_SIGHAND 999 * but not CLONE_THREAD task, switch to the new one. 1000 */ 1001 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); 1002 if (!newsighand) 1003 return -ENOMEM; 1004 1005 atomic_set(&newsighand->count, 1); 1006 memcpy(newsighand->action, oldsighand->action, 1007 sizeof(newsighand->action)); 1008 1009 write_lock_irq(&tasklist_lock); 1010 spin_lock(&oldsighand->siglock); 1011 rcu_assign_pointer(tsk->sighand, newsighand); 1012 spin_unlock(&oldsighand->siglock); 1013 write_unlock_irq(&tasklist_lock); 1014 1015 __cleanup_sighand(oldsighand); 1016 } 1017 1018 BUG_ON(!thread_group_leader(tsk)); 1019 return 0; 1020 1021 killed: 1022 /* protects against exit_notify() and __exit_signal() */ 1023 read_lock(&tasklist_lock); 1024 sig->group_exit_task = NULL; 1025 sig->notify_count = 0; 1026 read_unlock(&tasklist_lock); 1027 return -EAGAIN; 1028 } 1029 1030 char *get_task_comm(char *buf, struct task_struct *tsk) 1031 { 1032 /* buf must be at least sizeof(tsk->comm) in size */ 1033 task_lock(tsk); 1034 strncpy(buf, tsk->comm, sizeof(tsk->comm)); 1035 task_unlock(tsk); 1036 return buf; 1037 } 1038 EXPORT_SYMBOL_GPL(get_task_comm); 1039 1040 /* 1041 * These functions flushes out all traces of the currently running executable 1042 * so that a new one can be started 1043 */ 1044 1045 void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) 1046 { 1047 task_lock(tsk); 1048 trace_task_rename(tsk, buf); 1049 strlcpy(tsk->comm, buf, sizeof(tsk->comm)); 1050 task_unlock(tsk); 1051 perf_event_comm(tsk, exec); 1052 } 1053 1054 int flush_old_exec(struct linux_binprm * bprm) 1055 { 1056 int retval; 1057 1058 /* 1059 * Make sure we have a private signal table and that 1060 * we are unassociated from the previous thread group. 1061 */ 1062 retval = de_thread(current); 1063 if (retval) 1064 goto out; 1065 1066 set_mm_exe_file(bprm->mm, bprm->file); 1067 /* 1068 * Release all of the old mmap stuff 1069 */ 1070 acct_arg_size(bprm, 0); 1071 retval = exec_mmap(bprm->mm); 1072 if (retval) 1073 goto out; 1074 1075 bprm->mm = NULL; /* We're using it now */ 1076 1077 set_fs(USER_DS); 1078 current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | 1079 PF_NOFREEZE | PF_NO_SETAFFINITY); 1080 flush_thread(); 1081 current->personality &= ~bprm->per_clear; 1082 1083 return 0; 1084 1085 out: 1086 return retval; 1087 } 1088 EXPORT_SYMBOL(flush_old_exec); 1089 1090 void would_dump(struct linux_binprm *bprm, struct file *file) 1091 { 1092 if (inode_permission(file_inode(file), MAY_READ) < 0) 1093 bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; 1094 } 1095 EXPORT_SYMBOL(would_dump); 1096 1097 void setup_new_exec(struct linux_binprm * bprm) 1098 { 1099 arch_pick_mmap_layout(current->mm); 1100 1101 /* This is the point of no return */ 1102 current->sas_ss_sp = current->sas_ss_size = 0; 1103 1104 if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) 1105 set_dumpable(current->mm, SUID_DUMP_USER); 1106 else 1107 set_dumpable(current->mm, suid_dumpable); 1108 1109 perf_event_exec(); 1110 __set_task_comm(current, kbasename(bprm->filename), true); 1111 1112 /* Set the new mm task size. We have to do that late because it may 1113 * depend on TIF_32BIT which is only updated in flush_thread() on 1114 * some architectures like powerpc 1115 */ 1116 current->mm->task_size = TASK_SIZE; 1117 1118 /* install the new credentials */ 1119 if (!uid_eq(bprm->cred->uid, current_euid()) || 1120 !gid_eq(bprm->cred->gid, current_egid())) { 1121 current->pdeath_signal = 0; 1122 } else { 1123 would_dump(bprm, bprm->file); 1124 if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) 1125 set_dumpable(current->mm, suid_dumpable); 1126 } 1127 1128 /* An exec changes our domain. We are no longer part of the thread 1129 group */ 1130 current->self_exec_id++; 1131 flush_signal_handlers(current, 0); 1132 do_close_on_exec(current->files); 1133 } 1134 EXPORT_SYMBOL(setup_new_exec); 1135 1136 /* 1137 * Prepare credentials and lock ->cred_guard_mutex. 1138 * install_exec_creds() commits the new creds and drops the lock. 1139 * Or, if exec fails before, free_bprm() should release ->cred and 1140 * and unlock. 1141 */ 1142 int prepare_bprm_creds(struct linux_binprm *bprm) 1143 { 1144 if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) 1145 return -ERESTARTNOINTR; 1146 1147 bprm->cred = prepare_exec_creds(); 1148 if (likely(bprm->cred)) 1149 return 0; 1150 1151 mutex_unlock(¤t->signal->cred_guard_mutex); 1152 return -ENOMEM; 1153 } 1154 1155 static void free_bprm(struct linux_binprm *bprm) 1156 { 1157 free_arg_pages(bprm); 1158 if (bprm->cred) { 1159 mutex_unlock(¤t->signal->cred_guard_mutex); 1160 abort_creds(bprm->cred); 1161 } 1162 if (bprm->file) { 1163 allow_write_access(bprm->file); 1164 fput(bprm->file); 1165 } 1166 /* If a binfmt changed the interp, free it. */ 1167 if (bprm->interp != bprm->filename) 1168 kfree(bprm->interp); 1169 kfree(bprm); 1170 } 1171 1172 int bprm_change_interp(char *interp, struct linux_binprm *bprm) 1173 { 1174 /* If a binfmt changed the interp, free it first. */ 1175 if (bprm->interp != bprm->filename) 1176 kfree(bprm->interp); 1177 bprm->interp = kstrdup(interp, GFP_KERNEL); 1178 if (!bprm->interp) 1179 return -ENOMEM; 1180 return 0; 1181 } 1182 EXPORT_SYMBOL(bprm_change_interp); 1183 1184 /* 1185 * install the new credentials for this executable 1186 */ 1187 void install_exec_creds(struct linux_binprm *bprm) 1188 { 1189 security_bprm_committing_creds(bprm); 1190 1191 commit_creds(bprm->cred); 1192 bprm->cred = NULL; 1193 1194 /* 1195 * Disable monitoring for regular users 1196 * when executing setuid binaries. Must 1197 * wait until new credentials are committed 1198 * by commit_creds() above 1199 */ 1200 if (get_dumpable(current->mm) != SUID_DUMP_USER) 1201 perf_event_exit_task(current); 1202 /* 1203 * cred_guard_mutex must be held at least to this point to prevent 1204 * ptrace_attach() from altering our determination of the task's 1205 * credentials; any time after this it may be unlocked. 1206 */ 1207 security_bprm_committed_creds(bprm); 1208 mutex_unlock(¤t->signal->cred_guard_mutex); 1209 } 1210 EXPORT_SYMBOL(install_exec_creds); 1211 1212 /* 1213 * determine how safe it is to execute the proposed program 1214 * - the caller must hold ->cred_guard_mutex to protect against 1215 * PTRACE_ATTACH or seccomp thread-sync 1216 */ 1217 static void check_unsafe_exec(struct linux_binprm *bprm) 1218 { 1219 struct task_struct *p = current, *t; 1220 unsigned n_fs; 1221 1222 if (p->ptrace) { 1223 if (p->ptrace & PT_PTRACE_CAP) 1224 bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; 1225 else 1226 bprm->unsafe |= LSM_UNSAFE_PTRACE; 1227 } 1228 1229 /* 1230 * This isn't strictly necessary, but it makes it harder for LSMs to 1231 * mess up. 1232 */ 1233 if (task_no_new_privs(current)) 1234 bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; 1235 1236 t = p; 1237 n_fs = 1; 1238 spin_lock(&p->fs->lock); 1239 rcu_read_lock(); 1240 while_each_thread(p, t) { 1241 if (t->fs == p->fs) 1242 n_fs++; 1243 } 1244 rcu_read_unlock(); 1245 1246 if (p->fs->users > n_fs) 1247 bprm->unsafe |= LSM_UNSAFE_SHARE; 1248 else 1249 p->fs->in_exec = 1; 1250 spin_unlock(&p->fs->lock); 1251 } 1252 1253 /* 1254 * Fill the binprm structure from the inode. 1255 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes 1256 * 1257 * This may be called multiple times for binary chains (scripts for example). 1258 */ 1259 int prepare_binprm(struct linux_binprm *bprm) 1260 { 1261 struct inode *inode = file_inode(bprm->file); 1262 umode_t mode = inode->i_mode; 1263 int retval; 1264 1265 1266 /* clear any previous set[ug]id data from a previous binary */ 1267 bprm->cred->euid = current_euid(); 1268 bprm->cred->egid = current_egid(); 1269 1270 if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) && 1271 !task_no_new_privs(current) && 1272 kuid_has_mapping(bprm->cred->user_ns, inode->i_uid) && 1273 kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) { 1274 /* Set-uid? */ 1275 if (mode & S_ISUID) { 1276 bprm->per_clear |= PER_CLEAR_ON_SETID; 1277 bprm->cred->euid = inode->i_uid; 1278 } 1279 1280 /* Set-gid? */ 1281 /* 1282 * If setgid is set but no group execute bit then this 1283 * is a candidate for mandatory locking, not a setgid 1284 * executable. 1285 */ 1286 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { 1287 bprm->per_clear |= PER_CLEAR_ON_SETID; 1288 bprm->cred->egid = inode->i_gid; 1289 } 1290 } 1291 1292 /* fill in binprm security blob */ 1293 retval = security_bprm_set_creds(bprm); 1294 if (retval) 1295 return retval; 1296 bprm->cred_prepared = 1; 1297 1298 memset(bprm->buf, 0, BINPRM_BUF_SIZE); 1299 return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); 1300 } 1301 1302 EXPORT_SYMBOL(prepare_binprm); 1303 1304 /* 1305 * Arguments are '\0' separated strings found at the location bprm->p 1306 * points to; chop off the first by relocating brpm->p to right after 1307 * the first '\0' encountered. 1308 */ 1309 int remove_arg_zero(struct linux_binprm *bprm) 1310 { 1311 int ret = 0; 1312 unsigned long offset; 1313 char *kaddr; 1314 struct page *page; 1315 1316 if (!bprm->argc) 1317 return 0; 1318 1319 do { 1320 offset = bprm->p & ~PAGE_MASK; 1321 page = get_arg_page(bprm, bprm->p, 0); 1322 if (!page) { 1323 ret = -EFAULT; 1324 goto out; 1325 } 1326 kaddr = kmap_atomic(page); 1327 1328 for (; offset < PAGE_SIZE && kaddr[offset]; 1329 offset++, bprm->p++) 1330 ; 1331 1332 kunmap_atomic(kaddr); 1333 put_arg_page(page); 1334 1335 if (offset == PAGE_SIZE) 1336 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); 1337 } while (offset == PAGE_SIZE); 1338 1339 bprm->p++; 1340 bprm->argc--; 1341 ret = 0; 1342 1343 out: 1344 return ret; 1345 } 1346 EXPORT_SYMBOL(remove_arg_zero); 1347 1348 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) 1349 /* 1350 * cycle the list of binary formats handler, until one recognizes the image 1351 */ 1352 int search_binary_handler(struct linux_binprm *bprm) 1353 { 1354 bool need_retry = IS_ENABLED(CONFIG_MODULES); 1355 struct linux_binfmt *fmt; 1356 int retval; 1357 1358 /* This allows 4 levels of binfmt rewrites before failing hard. */ 1359 if (bprm->recursion_depth > 5) 1360 return -ELOOP; 1361 1362 retval = security_bprm_check(bprm); 1363 if (retval) 1364 return retval; 1365 1366 retval = -ENOENT; 1367 retry: 1368 read_lock(&binfmt_lock); 1369 list_for_each_entry(fmt, &formats, lh) { 1370 if (!try_module_get(fmt->module)) 1371 continue; 1372 read_unlock(&binfmt_lock); 1373 bprm->recursion_depth++; 1374 retval = fmt->load_binary(bprm); 1375 read_lock(&binfmt_lock); 1376 put_binfmt(fmt); 1377 bprm->recursion_depth--; 1378 if (retval < 0 && !bprm->mm) { 1379 /* we got to flush_old_exec() and failed after it */ 1380 read_unlock(&binfmt_lock); 1381 force_sigsegv(SIGSEGV, current); 1382 return retval; 1383 } 1384 if (retval != -ENOEXEC || !bprm->file) { 1385 read_unlock(&binfmt_lock); 1386 return retval; 1387 } 1388 } 1389 read_unlock(&binfmt_lock); 1390 1391 if (need_retry) { 1392 if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && 1393 printable(bprm->buf[2]) && printable(bprm->buf[3])) 1394 return retval; 1395 if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) 1396 return retval; 1397 need_retry = false; 1398 goto retry; 1399 } 1400 1401 return retval; 1402 } 1403 EXPORT_SYMBOL(search_binary_handler); 1404 1405 static int exec_binprm(struct linux_binprm *bprm) 1406 { 1407 pid_t old_pid, old_vpid; 1408 int ret; 1409 1410 /* Need to fetch pid before load_binary changes it */ 1411 old_pid = current->pid; 1412 rcu_read_lock(); 1413 old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); 1414 rcu_read_unlock(); 1415 1416 ret = search_binary_handler(bprm); 1417 if (ret >= 0) { 1418 audit_bprm(bprm); 1419 trace_sched_process_exec(current, old_pid, bprm); 1420 ptrace_event(PTRACE_EVENT_EXEC, old_vpid); 1421 proc_exec_connector(current); 1422 } 1423 1424 return ret; 1425 } 1426 1427 /* 1428 * sys_execve() executes a new program. 1429 */ 1430 static int do_execve_common(struct filename *filename, 1431 struct user_arg_ptr argv, 1432 struct user_arg_ptr envp) 1433 { 1434 struct linux_binprm *bprm; 1435 struct file *file; 1436 struct files_struct *displaced; 1437 int retval; 1438 1439 if (IS_ERR(filename)) 1440 return PTR_ERR(filename); 1441 1442 /* 1443 * We move the actual failure in case of RLIMIT_NPROC excess from 1444 * set*uid() to execve() because too many poorly written programs 1445 * don't check setuid() return code. Here we additionally recheck 1446 * whether NPROC limit is still exceeded. 1447 */ 1448 if ((current->flags & PF_NPROC_EXCEEDED) && 1449 atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { 1450 retval = -EAGAIN; 1451 goto out_ret; 1452 } 1453 1454 /* We're below the limit (still or again), so we don't want to make 1455 * further execve() calls fail. */ 1456 current->flags &= ~PF_NPROC_EXCEEDED; 1457 1458 retval = unshare_files(&displaced); 1459 if (retval) 1460 goto out_ret; 1461 1462 retval = -ENOMEM; 1463 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); 1464 if (!bprm) 1465 goto out_files; 1466 1467 retval = prepare_bprm_creds(bprm); 1468 if (retval) 1469 goto out_free; 1470 1471 check_unsafe_exec(bprm); 1472 current->in_execve = 1; 1473 1474 file = do_open_exec(filename); 1475 retval = PTR_ERR(file); 1476 if (IS_ERR(file)) 1477 goto out_unmark; 1478 1479 sched_exec(); 1480 1481 bprm->file = file; 1482 bprm->filename = bprm->interp = filename->name; 1483 1484 retval = bprm_mm_init(bprm); 1485 if (retval) 1486 goto out_unmark; 1487 1488 bprm->argc = count(argv, MAX_ARG_STRINGS); 1489 if ((retval = bprm->argc) < 0) 1490 goto out; 1491 1492 bprm->envc = count(envp, MAX_ARG_STRINGS); 1493 if ((retval = bprm->envc) < 0) 1494 goto out; 1495 1496 retval = prepare_binprm(bprm); 1497 if (retval < 0) 1498 goto out; 1499 1500 retval = copy_strings_kernel(1, &bprm->filename, bprm); 1501 if (retval < 0) 1502 goto out; 1503 1504 bprm->exec = bprm->p; 1505 retval = copy_strings(bprm->envc, envp, bprm); 1506 if (retval < 0) 1507 goto out; 1508 1509 retval = copy_strings(bprm->argc, argv, bprm); 1510 if (retval < 0) 1511 goto out; 1512 1513 retval = exec_binprm(bprm); 1514 if (retval < 0) 1515 goto out; 1516 1517 /* execve succeeded */ 1518 current->fs->in_exec = 0; 1519 current->in_execve = 0; 1520 acct_update_integrals(current); 1521 task_numa_free(current); 1522 free_bprm(bprm); 1523 putname(filename); 1524 if (displaced) 1525 put_files_struct(displaced); 1526 return retval; 1527 1528 out: 1529 if (bprm->mm) { 1530 acct_arg_size(bprm, 0); 1531 mmput(bprm->mm); 1532 } 1533 1534 out_unmark: 1535 current->fs->in_exec = 0; 1536 current->in_execve = 0; 1537 1538 out_free: 1539 free_bprm(bprm); 1540 1541 out_files: 1542 if (displaced) 1543 reset_files_struct(displaced); 1544 out_ret: 1545 putname(filename); 1546 return retval; 1547 } 1548 1549 int do_execve(struct filename *filename, 1550 const char __user *const __user *__argv, 1551 const char __user *const __user *__envp) 1552 { 1553 struct user_arg_ptr argv = { .ptr.native = __argv }; 1554 struct user_arg_ptr envp = { .ptr.native = __envp }; 1555 return do_execve_common(filename, argv, envp); 1556 } 1557 1558 #ifdef CONFIG_COMPAT 1559 static int compat_do_execve(struct filename *filename, 1560 const compat_uptr_t __user *__argv, 1561 const compat_uptr_t __user *__envp) 1562 { 1563 struct user_arg_ptr argv = { 1564 .is_compat = true, 1565 .ptr.compat = __argv, 1566 }; 1567 struct user_arg_ptr envp = { 1568 .is_compat = true, 1569 .ptr.compat = __envp, 1570 }; 1571 return do_execve_common(filename, argv, envp); 1572 } 1573 #endif 1574 1575 void set_binfmt(struct linux_binfmt *new) 1576 { 1577 struct mm_struct *mm = current->mm; 1578 1579 if (mm->binfmt) 1580 module_put(mm->binfmt->module); 1581 1582 mm->binfmt = new; 1583 if (new) 1584 __module_get(new->module); 1585 } 1586 EXPORT_SYMBOL(set_binfmt); 1587 1588 /* 1589 * set_dumpable stores three-value SUID_DUMP_* into mm->flags. 1590 */ 1591 void set_dumpable(struct mm_struct *mm, int value) 1592 { 1593 unsigned long old, new; 1594 1595 if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) 1596 return; 1597 1598 do { 1599 old = ACCESS_ONCE(mm->flags); 1600 new = (old & ~MMF_DUMPABLE_MASK) | value; 1601 } while (cmpxchg(&mm->flags, old, new) != old); 1602 } 1603 1604 SYSCALL_DEFINE3(execve, 1605 const char __user *, filename, 1606 const char __user *const __user *, argv, 1607 const char __user *const __user *, envp) 1608 { 1609 return do_execve(getname(filename), argv, envp); 1610 } 1611 #ifdef CONFIG_COMPAT 1612 COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, 1613 const compat_uptr_t __user *, argv, 1614 const compat_uptr_t __user *, envp) 1615 { 1616 return compat_do_execve(getname(filename), argv, envp); 1617 } 1618 #endif 1619