projects/linux·blob v4.0-rc6 · refs

1712 lines · 40.0 KiB

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
69int suid_dumpable = 0;
70
71static LIST_HEAD(formats);
72static DEFINE_RWLOCK(binfmt_lock);
73
74void __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
85EXPORT_SYMBOL(__register_binfmt);
86
87void unregister_binfmt(struct linux_binfmt * fmt)
88{
89 write_lock(&binfmt_lock);
90 list_del(&fmt->lh);
91 write_unlock(&binfmt_lock);
92}
93
94EXPORT_SYMBOL(unregister_binfmt);
95
96static 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 */
108SYSCALL_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);
156exit:
157 fput(file);
158out:
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 */
170static 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
182static 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
230static void put_arg_page(struct page *page)
231{
232 put_page(page);
233}
234
235static void free_arg_page(struct linux_binprm *bprm, int i)
236{
237}
238
239static void free_arg_pages(struct linux_binprm *bprm)
240{
241}
242
243static 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
249static 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 arch_bprm_mm_init(mm, vma);
281 up_write(&mm->mmap_sem);
282 bprm->p = vma->vm_end - sizeof(void *);
283 return 0;
284err:
285 up_write(&mm->mmap_sem);
286 bprm->vma = NULL;
287 kmem_cache_free(vm_area_cachep, vma);
288 return err;
289}
290
291static bool valid_arg_len(struct linux_binprm *bprm, long len)
292{
293 return len <= MAX_ARG_STRLEN;
294}
295
296#else
297
298static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
299{
300}
301
302static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
303 int write)
304{
305 struct page *page;
306
307 page = bprm->page[pos / PAGE_SIZE];
308 if (!page && write) {
309 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
310 if (!page)
311 return NULL;
312 bprm->page[pos / PAGE_SIZE] = page;
313 }
314
315 return page;
316}
317
318static void put_arg_page(struct page *page)
319{
320}
321
322static void free_arg_page(struct linux_binprm *bprm, int i)
323{
324 if (bprm->page[i]) {
325 __free_page(bprm->page[i]);
326 bprm->page[i] = NULL;
327 }
328}
329
330static void free_arg_pages(struct linux_binprm *bprm)
331{
332 int i;
333
334 for (i = 0; i < MAX_ARG_PAGES; i++)
335 free_arg_page(bprm, i);
336}
337
338static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
339 struct page *page)
340{
341}
342
343static int __bprm_mm_init(struct linux_binprm *bprm)
344{
345 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
346 return 0;
347}
348
349static bool valid_arg_len(struct linux_binprm *bprm, long len)
350{
351 return len <= bprm->p;
352}
353
354#endif /* CONFIG_MMU */
355
356/*
357 * Create a new mm_struct and populate it with a temporary stack
358 * vm_area_struct. We don't have enough context at this point to set the stack
359 * flags, permissions, and offset, so we use temporary values. We'll update
360 * them later in setup_arg_pages().
361 */
362static int bprm_mm_init(struct linux_binprm *bprm)
363{
364 int err;
365 struct mm_struct *mm = NULL;
366
367 bprm->mm = mm = mm_alloc();
368 err = -ENOMEM;
369 if (!mm)
370 goto err;
371
372 err = __bprm_mm_init(bprm);
373 if (err)
374 goto err;
375
376 return 0;
377
378err:
379 if (mm) {
380 bprm->mm = NULL;
381 mmdrop(mm);
382 }
383
384 return err;
385}
386
387struct user_arg_ptr {
388#ifdef CONFIG_COMPAT
389 bool is_compat;
390#endif
391 union {
392 const char __user *const __user *native;
393#ifdef CONFIG_COMPAT
394 const compat_uptr_t __user *compat;
395#endif
396 } ptr;
397};
398
399static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
400{
401 const char __user *native;
402
403#ifdef CONFIG_COMPAT
404 if (unlikely(argv.is_compat)) {
405 compat_uptr_t compat;
406
407 if (get_user(compat, argv.ptr.compat + nr))
408 return ERR_PTR(-EFAULT);
409
410 return compat_ptr(compat);
411 }
412#endif
413
414 if (get_user(native, argv.ptr.native + nr))
415 return ERR_PTR(-EFAULT);
416
417 return native;
418}
419
420/*
421 * count() counts the number of strings in array ARGV.
422 */
423static int count(struct user_arg_ptr argv, int max)
424{
425 int i = 0;
426
427 if (argv.ptr.native != NULL) {
428 for (;;) {
429 const char __user *p = get_user_arg_ptr(argv, i);
430
431 if (!p)
432 break;
433
434 if (IS_ERR(p))
435 return -EFAULT;
436
437 if (i >= max)
438 return -E2BIG;
439 ++i;
440
441 if (fatal_signal_pending(current))
442 return -ERESTARTNOHAND;
443 cond_resched();
444 }
445 }
446 return i;
447}
448
449/*
450 * 'copy_strings()' copies argument/environment strings from the old
451 * processes's memory to the new process's stack. The call to get_user_pages()
452 * ensures the destination page is created and not swapped out.
453 */
454static int copy_strings(int argc, struct user_arg_ptr argv,
455 struct linux_binprm *bprm)
456{
457 struct page *kmapped_page = NULL;
458 char *kaddr = NULL;
459 unsigned long kpos = 0;
460 int ret;
461
462 while (argc-- > 0) {
463 const char __user *str;
464 int len;
465 unsigned long pos;
466
467 ret = -EFAULT;
468 str = get_user_arg_ptr(argv, argc);
469 if (IS_ERR(str))
470 goto out;
471
472 len = strnlen_user(str, MAX_ARG_STRLEN);
473 if (!len)
474 goto out;
475
476 ret = -E2BIG;
477 if (!valid_arg_len(bprm, len))
478 goto out;
479
480 /* We're going to work our way backwords. */
481 pos = bprm->p;
482 str += len;
483 bprm->p -= len;
484
485 while (len > 0) {
486 int offset, bytes_to_copy;
487
488 if (fatal_signal_pending(current)) {
489 ret = -ERESTARTNOHAND;
490 goto out;
491 }
492 cond_resched();
493
494 offset = pos % PAGE_SIZE;
495 if (offset == 0)
496 offset = PAGE_SIZE;
497
498 bytes_to_copy = offset;
499 if (bytes_to_copy > len)
500 bytes_to_copy = len;
501
502 offset -= bytes_to_copy;
503 pos -= bytes_to_copy;
504 str -= bytes_to_copy;
505 len -= bytes_to_copy;
506
507 if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
508 struct page *page;
509
510 page = get_arg_page(bprm, pos, 1);
511 if (!page) {
512 ret = -E2BIG;
513 goto out;
514 }
515
516 if (kmapped_page) {
517 flush_kernel_dcache_page(kmapped_page);
518 kunmap(kmapped_page);
519 put_arg_page(kmapped_page);
520 }
521 kmapped_page = page;
522 kaddr = kmap(kmapped_page);
523 kpos = pos & PAGE_MASK;
524 flush_arg_page(bprm, kpos, kmapped_page);
525 }
526 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
527 ret = -EFAULT;
528 goto out;
529 }
530 }
531 }
532 ret = 0;
533out:
534 if (kmapped_page) {
535 flush_kernel_dcache_page(kmapped_page);
536 kunmap(kmapped_page);
537 put_arg_page(kmapped_page);
538 }
539 return ret;
540}
541
542/*
543 * Like copy_strings, but get argv and its values from kernel memory.
544 */
545int copy_strings_kernel(int argc, const char *const *__argv,
546 struct linux_binprm *bprm)
547{
548 int r;
549 mm_segment_t oldfs = get_fs();
550 struct user_arg_ptr argv = {
551 .ptr.native = (const char __user *const __user *)__argv,
552 };
553
554 set_fs(KERNEL_DS);
555 r = copy_strings(argc, argv, bprm);
556 set_fs(oldfs);
557
558 return r;
559}
560EXPORT_SYMBOL(copy_strings_kernel);
561
562#ifdef CONFIG_MMU
563
564/*
565 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
566 * the binfmt code determines where the new stack should reside, we shift it to
567 * its final location. The process proceeds as follows:
568 *
569 * 1) Use shift to calculate the new vma endpoints.
570 * 2) Extend vma to cover both the old and new ranges. This ensures the
571 * arguments passed to subsequent functions are consistent.
572 * 3) Move vma's page tables to the new range.
573 * 4) Free up any cleared pgd range.
574 * 5) Shrink the vma to cover only the new range.
575 */
576static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
577{
578 struct mm_struct *mm = vma->vm_mm;
579 unsigned long old_start = vma->vm_start;
580 unsigned long old_end = vma->vm_end;
581 unsigned long length = old_end - old_start;
582 unsigned long new_start = old_start - shift;
583 unsigned long new_end = old_end - shift;
584 struct mmu_gather tlb;
585
586 BUG_ON(new_start > new_end);
587
588 /*
589 * ensure there are no vmas between where we want to go
590 * and where we are
591 */
592 if (vma != find_vma(mm, new_start))
593 return -EFAULT;
594
595 /*
596 * cover the whole range: [new_start, old_end)
597 */
598 if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
599 return -ENOMEM;
600
601 /*
602 * move the page tables downwards, on failure we rely on
603 * process cleanup to remove whatever mess we made.
604 */
605 if (length != move_page_tables(vma, old_start,
606 vma, new_start, length, false))
607 return -ENOMEM;
608
609 lru_add_drain();
610 tlb_gather_mmu(&tlb, mm, old_start, old_end);
611 if (new_end > old_start) {
612 /*
613 * when the old and new regions overlap clear from new_end.
614 */
615 free_pgd_range(&tlb, new_end, old_end, new_end,
616 vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
617 } else {
618 /*
619 * otherwise, clean from old_start; this is done to not touch
620 * the address space in [new_end, old_start) some architectures
621 * have constraints on va-space that make this illegal (IA64) -
622 * for the others its just a little faster.
623 */
624 free_pgd_range(&tlb, old_start, old_end, new_end,
625 vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING);
626 }
627 tlb_finish_mmu(&tlb, old_start, old_end);
628
629 /*
630 * Shrink the vma to just the new range. Always succeeds.
631 */
632 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
633
634 return 0;
635}
636
637/*
638 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
639 * the stack is optionally relocated, and some extra space is added.
640 */
641int setup_arg_pages(struct linux_binprm *bprm,
642 unsigned long stack_top,
643 int executable_stack)
644{
645 unsigned long ret;
646 unsigned long stack_shift;
647 struct mm_struct *mm = current->mm;
648 struct vm_area_struct *vma = bprm->vma;
649 struct vm_area_struct *prev = NULL;
650 unsigned long vm_flags;
651 unsigned long stack_base;
652 unsigned long stack_size;
653 unsigned long stack_expand;
654 unsigned long rlim_stack;
655
656#ifdef CONFIG_STACK_GROWSUP
657 /* Limit stack size */
658 stack_base = rlimit_max(RLIMIT_STACK);
659 if (stack_base > STACK_SIZE_MAX)
660 stack_base = STACK_SIZE_MAX;
661
662 /* Make sure we didn't let the argument array grow too large. */
663 if (vma->vm_end - vma->vm_start > stack_base)
664 return -ENOMEM;
665
666 stack_base = PAGE_ALIGN(stack_top - stack_base);
667
668 stack_shift = vma->vm_start - stack_base;
669 mm->arg_start = bprm->p - stack_shift;
670 bprm->p = vma->vm_end - stack_shift;
671#else
672 stack_top = arch_align_stack(stack_top);
673 stack_top = PAGE_ALIGN(stack_top);
674
675 if (unlikely(stack_top < mmap_min_addr) ||
676 unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
677 return -ENOMEM;
678
679 stack_shift = vma->vm_end - stack_top;
680
681 bprm->p -= stack_shift;
682 mm->arg_start = bprm->p;
683#endif
684
685 if (bprm->loader)
686 bprm->loader -= stack_shift;
687 bprm->exec -= stack_shift;
688
689 down_write(&mm->mmap_sem);
690 vm_flags = VM_STACK_FLAGS;
691
692 /*
693 * Adjust stack execute permissions; explicitly enable for
694 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
695 * (arch default) otherwise.
696 */
697 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
698 vm_flags |= VM_EXEC;
699 else if (executable_stack == EXSTACK_DISABLE_X)
700 vm_flags &= ~VM_EXEC;
701 vm_flags |= mm->def_flags;
702 vm_flags |= VM_STACK_INCOMPLETE_SETUP;
703
704 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
705 vm_flags);
706 if (ret)
707 goto out_unlock;
708 BUG_ON(prev != vma);
709
710 /* Move stack pages down in memory. */
711 if (stack_shift) {
712 ret = shift_arg_pages(vma, stack_shift);
713 if (ret)
714 goto out_unlock;
715 }
716
717 /* mprotect_fixup is overkill to remove the temporary stack flags */
718 vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP;
719
720 stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
721 stack_size = vma->vm_end - vma->vm_start;
722 /*
723 * Align this down to a page boundary as expand_stack
724 * will align it up.
725 */
726 rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK;
727#ifdef CONFIG_STACK_GROWSUP
728 if (stack_size + stack_expand > rlim_stack)
729 stack_base = vma->vm_start + rlim_stack;
730 else
731 stack_base = vma->vm_end + stack_expand;
732#else
733 if (stack_size + stack_expand > rlim_stack)
734 stack_base = vma->vm_end - rlim_stack;
735 else
736 stack_base = vma->vm_start - stack_expand;
737#endif
738 current->mm->start_stack = bprm->p;
739 ret = expand_stack(vma, stack_base);
740 if (ret)
741 ret = -EFAULT;
742
743out_unlock:
744 up_write(&mm->mmap_sem);
745 return ret;
746}
747EXPORT_SYMBOL(setup_arg_pages);
748
749#endif /* CONFIG_MMU */
750
751static struct file *do_open_execat(int fd, struct filename *name, int flags)
752{
753 struct file *file;
754 int err;
755 struct open_flags open_exec_flags = {
756 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
757 .acc_mode = MAY_EXEC | MAY_OPEN,
758 .intent = LOOKUP_OPEN,
759 .lookup_flags = LOOKUP_FOLLOW,
760 };
761
762 if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
763 return ERR_PTR(-EINVAL);
764 if (flags & AT_SYMLINK_NOFOLLOW)
765 open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
766 if (flags & AT_EMPTY_PATH)
767 open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
768
769 file = do_filp_open(fd, name, &open_exec_flags);
770 if (IS_ERR(file))
771 goto out;
772
773 err = -EACCES;
774 if (!S_ISREG(file_inode(file)->i_mode))
775 goto exit;
776
777 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
778 goto exit;
779
780 err = deny_write_access(file);
781 if (err)
782 goto exit;
783
784 if (name->name[0] != '\0')
785 fsnotify_open(file);
786
787out:
788 return file;
789
790exit:
791 fput(file);
792 return ERR_PTR(err);
793}
794
795struct file *open_exec(const char *name)
796{
797 struct filename *filename = getname_kernel(name);
798 struct file *f = ERR_CAST(filename);
799
800 if (!IS_ERR(filename)) {
801 f = do_open_execat(AT_FDCWD, filename, 0);
802 putname(filename);
803 }
804 return f;
805}
806EXPORT_SYMBOL(open_exec);
807
808int kernel_read(struct file *file, loff_t offset,
809 char *addr, unsigned long count)
810{
811 mm_segment_t old_fs;
812 loff_t pos = offset;
813 int result;
814
815 old_fs = get_fs();
816 set_fs(get_ds());
817 /* The cast to a user pointer is valid due to the set_fs() */
818 result = vfs_read(file, (void __user *)addr, count, &pos);
819 set_fs(old_fs);
820 return result;
821}
822
823EXPORT_SYMBOL(kernel_read);
824
825ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
826{
827 ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
828 if (res > 0)
829 flush_icache_range(addr, addr + len);
830 return res;
831}
832EXPORT_SYMBOL(read_code);
833
834static int exec_mmap(struct mm_struct *mm)
835{
836 struct task_struct *tsk;
837 struct mm_struct *old_mm, *active_mm;
838
839 /* Notify parent that we're no longer interested in the old VM */
840 tsk = current;
841 old_mm = current->mm;
842 mm_release(tsk, old_mm);
843
844 if (old_mm) {
845 sync_mm_rss(old_mm);
846 /*
847 * Make sure that if there is a core dump in progress
848 * for the old mm, we get out and die instead of going
849 * through with the exec. We must hold mmap_sem around
850 * checking core_state and changing tsk->mm.
851 */
852 down_read(&old_mm->mmap_sem);
853 if (unlikely(old_mm->core_state)) {
854 up_read(&old_mm->mmap_sem);
855 return -EINTR;
856 }
857 }
858 task_lock(tsk);
859 active_mm = tsk->active_mm;
860 tsk->mm = mm;
861 tsk->active_mm = mm;
862 activate_mm(active_mm, mm);
863 tsk->mm->vmacache_seqnum = 0;
864 vmacache_flush(tsk);
865 task_unlock(tsk);
866 if (old_mm) {
867 up_read(&old_mm->mmap_sem);
868 BUG_ON(active_mm != old_mm);
869 setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm);
870 mm_update_next_owner(old_mm);
871 mmput(old_mm);
872 return 0;
873 }
874 mmdrop(active_mm);
875 return 0;
876}
877
878/*
879 * This function makes sure the current process has its own signal table,
880 * so that flush_signal_handlers can later reset the handlers without
881 * disturbing other processes. (Other processes might share the signal
882 * table via the CLONE_SIGHAND option to clone().)
883 */
884static int de_thread(struct task_struct *tsk)
885{
886 struct signal_struct *sig = tsk->signal;
887 struct sighand_struct *oldsighand = tsk->sighand;
888 spinlock_t *lock = &oldsighand->siglock;
889
890 if (thread_group_empty(tsk))
891 goto no_thread_group;
892
893 /*
894 * Kill all other threads in the thread group.
895 */
896 spin_lock_irq(lock);
897 if (signal_group_exit(sig)) {
898 /*
899 * Another group action in progress, just
900 * return so that the signal is processed.
901 */
902 spin_unlock_irq(lock);
903 return -EAGAIN;
904 }
905
906 sig->group_exit_task = tsk;
907 sig->notify_count = zap_other_threads(tsk);
908 if (!thread_group_leader(tsk))
909 sig->notify_count--;
910
911 while (sig->notify_count) {
912 __set_current_state(TASK_KILLABLE);
913 spin_unlock_irq(lock);
914 schedule();
915 if (unlikely(__fatal_signal_pending(tsk)))
916 goto killed;
917 spin_lock_irq(lock);
918 }
919 spin_unlock_irq(lock);
920
921 /*
922 * At this point all other threads have exited, all we have to
923 * do is to wait for the thread group leader to become inactive,
924 * and to assume its PID:
925 */
926 if (!thread_group_leader(tsk)) {
927 struct task_struct *leader = tsk->group_leader;
928
929 sig->notify_count = -1; /* for exit_notify() */
930 for (;;) {
931 threadgroup_change_begin(tsk);
932 write_lock_irq(&tasklist_lock);
933 if (likely(leader->exit_state))
934 break;
935 __set_current_state(TASK_KILLABLE);
936 write_unlock_irq(&tasklist_lock);
937 threadgroup_change_end(tsk);
938 schedule();
939 if (unlikely(__fatal_signal_pending(tsk)))
940 goto killed;
941 }
942
943 /*
944 * The only record we have of the real-time age of a
945 * process, regardless of execs it's done, is start_time.
946 * All the past CPU time is accumulated in signal_struct
947 * from sister threads now dead. But in this non-leader
948 * exec, nothing survives from the original leader thread,
949 * whose birth marks the true age of this process now.
950 * When we take on its identity by switching to its PID, we
951 * also take its birthdate (always earlier than our own).
952 */
953 tsk->start_time = leader->start_time;
954 tsk->real_start_time = leader->real_start_time;
955
956 BUG_ON(!same_thread_group(leader, tsk));
957 BUG_ON(has_group_leader_pid(tsk));
958 /*
959 * An exec() starts a new thread group with the
960 * TGID of the previous thread group. Rehash the
961 * two threads with a switched PID, and release
962 * the former thread group leader:
963 */
964
965 /* Become a process group leader with the old leader's pid.
966 * The old leader becomes a thread of the this thread group.
967 * Note: The old leader also uses this pid until release_task
968 * is called. Odd but simple and correct.
969 */
970 tsk->pid = leader->pid;
971 change_pid(tsk, PIDTYPE_PID, task_pid(leader));
972 transfer_pid(leader, tsk, PIDTYPE_PGID);
973 transfer_pid(leader, tsk, PIDTYPE_SID);
974
975 list_replace_rcu(&leader->tasks, &tsk->tasks);
976 list_replace_init(&leader->sibling, &tsk->sibling);
977
978 tsk->group_leader = tsk;
979 leader->group_leader = tsk;
980
981 tsk->exit_signal = SIGCHLD;
982 leader->exit_signal = -1;
983
984 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
985 leader->exit_state = EXIT_DEAD;
986
987 /*
988 * We are going to release_task()->ptrace_unlink() silently,
989 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
990 * the tracer wont't block again waiting for this thread.
991 */
992 if (unlikely(leader->ptrace))
993 __wake_up_parent(leader, leader->parent);
994 write_unlock_irq(&tasklist_lock);
995 threadgroup_change_end(tsk);
996
997 release_task(leader);
998 }
999
1000 sig->group_exit_task = NULL;
1001 sig->notify_count = 0;
1002
1003no_thread_group:
1004 /* we have changed execution domain */
1005 tsk->exit_signal = SIGCHLD;
1006
1007 exit_itimers(sig);
1008 flush_itimer_signals();
1009
1010 if (atomic_read(&oldsighand->count) != 1) {
1011 struct sighand_struct *newsighand;
1012 /*
1013 * This ->sighand is shared with the CLONE_SIGHAND
1014 * but not CLONE_THREAD task, switch to the new one.
1015 */
1016 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
1017 if (!newsighand)
1018 return -ENOMEM;
1019
1020 atomic_set(&newsighand->count, 1);
1021 memcpy(newsighand->action, oldsighand->action,
1022 sizeof(newsighand->action));
1023
1024 write_lock_irq(&tasklist_lock);
1025 spin_lock(&oldsighand->siglock);
1026 rcu_assign_pointer(tsk->sighand, newsighand);
1027 spin_unlock(&oldsighand->siglock);
1028 write_unlock_irq(&tasklist_lock);
1029
1030 __cleanup_sighand(oldsighand);
1031 }
1032
1033 BUG_ON(!thread_group_leader(tsk));
1034 return 0;
1035
1036killed:
1037 /* protects against exit_notify() and __exit_signal() */
1038 read_lock(&tasklist_lock);
1039 sig->group_exit_task = NULL;
1040 sig->notify_count = 0;
1041 read_unlock(&tasklist_lock);
1042 return -EAGAIN;
1043}
1044
1045char *get_task_comm(char *buf, struct task_struct *tsk)
1046{
1047 /* buf must be at least sizeof(tsk->comm) in size */
1048 task_lock(tsk);
1049 strncpy(buf, tsk->comm, sizeof(tsk->comm));
1050 task_unlock(tsk);
1051 return buf;
1052}
1053EXPORT_SYMBOL_GPL(get_task_comm);
1054
1055/*
1056 * These functions flushes out all traces of the currently running executable
1057 * so that a new one can be started
1058 */
1059
1060void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
1061{
1062 task_lock(tsk);
1063 trace_task_rename(tsk, buf);
1064 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
1065 task_unlock(tsk);
1066 perf_event_comm(tsk, exec);
1067}
1068
1069int flush_old_exec(struct linux_binprm * bprm)
1070{
1071 int retval;
1072
1073 /*
1074 * Make sure we have a private signal table and that
1075 * we are unassociated from the previous thread group.
1076 */
1077 retval = de_thread(current);
1078 if (retval)
1079 goto out;
1080
1081 set_mm_exe_file(bprm->mm, bprm->file);
1082 /*
1083 * Release all of the old mmap stuff
1084 */
1085 acct_arg_size(bprm, 0);
1086 retval = exec_mmap(bprm->mm);
1087 if (retval)
1088 goto out;
1089
1090 bprm->mm = NULL; /* We're using it now */
1091
1092 set_fs(USER_DS);
1093 current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
1094 PF_NOFREEZE | PF_NO_SETAFFINITY);
1095 flush_thread();
1096 current->personality &= ~bprm->per_clear;
1097
1098 return 0;
1099
1100out:
1101 return retval;
1102}
1103EXPORT_SYMBOL(flush_old_exec);
1104
1105void would_dump(struct linux_binprm *bprm, struct file *file)
1106{
1107 if (inode_permission(file_inode(file), MAY_READ) < 0)
1108 bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
1109}
1110EXPORT_SYMBOL(would_dump);
1111
1112void setup_new_exec(struct linux_binprm * bprm)
1113{
1114 arch_pick_mmap_layout(current->mm);
1115
1116 /* This is the point of no return */
1117 current->sas_ss_sp = current->sas_ss_size = 0;
1118
1119 if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
1120 set_dumpable(current->mm, SUID_DUMP_USER);
1121 else
1122 set_dumpable(current->mm, suid_dumpable);
1123
1124 perf_event_exec();
1125 __set_task_comm(current, kbasename(bprm->filename), true);
1126
1127 /* Set the new mm task size. We have to do that late because it may
1128 * depend on TIF_32BIT which is only updated in flush_thread() on
1129 * some architectures like powerpc
1130 */
1131 current->mm->task_size = TASK_SIZE;
1132
1133 /* install the new credentials */
1134 if (!uid_eq(bprm->cred->uid, current_euid()) ||
1135 !gid_eq(bprm->cred->gid, current_egid())) {
1136 current->pdeath_signal = 0;
1137 } else {
1138 would_dump(bprm, bprm->file);
1139 if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
1140 set_dumpable(current->mm, suid_dumpable);
1141 }
1142
1143 /* An exec changes our domain. We are no longer part of the thread
1144 group */
1145 current->self_exec_id++;
1146 flush_signal_handlers(current, 0);
1147 do_close_on_exec(current->files);
1148}
1149EXPORT_SYMBOL(setup_new_exec);
1150
1151/*
1152 * Prepare credentials and lock ->cred_guard_mutex.
1153 * install_exec_creds() commits the new creds and drops the lock.
1154 * Or, if exec fails before, free_bprm() should release ->cred and
1155 * and unlock.
1156 */
1157int prepare_bprm_creds(struct linux_binprm *bprm)
1158{
1159 if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
1160 return -ERESTARTNOINTR;
1161
1162 bprm->cred = prepare_exec_creds();
1163 if (likely(bprm->cred))
1164 return 0;
1165
1166 mutex_unlock(&current->signal->cred_guard_mutex);
1167 return -ENOMEM;
1168}
1169
1170static void free_bprm(struct linux_binprm *bprm)
1171{
1172 free_arg_pages(bprm);
1173 if (bprm->cred) {
1174 mutex_unlock(&current->signal->cred_guard_mutex);
1175 abort_creds(bprm->cred);
1176 }
1177 if (bprm->file) {
1178 allow_write_access(bprm->file);
1179 fput(bprm->file);
1180 }
1181 /* If a binfmt changed the interp, free it. */
1182 if (bprm->interp != bprm->filename)
1183 kfree(bprm->interp);
1184 kfree(bprm);
1185}
1186
1187int bprm_change_interp(char *interp, struct linux_binprm *bprm)
1188{
1189 /* If a binfmt changed the interp, free it first. */
1190 if (bprm->interp != bprm->filename)
1191 kfree(bprm->interp);
1192 bprm->interp = kstrdup(interp, GFP_KERNEL);
1193 if (!bprm->interp)
1194 return -ENOMEM;
1195 return 0;
1196}
1197EXPORT_SYMBOL(bprm_change_interp);
1198
1199/*
1200 * install the new credentials for this executable
1201 */
1202void install_exec_creds(struct linux_binprm *bprm)
1203{
1204 security_bprm_committing_creds(bprm);
1205
1206 commit_creds(bprm->cred);
1207 bprm->cred = NULL;
1208
1209 /*
1210 * Disable monitoring for regular users
1211 * when executing setuid binaries. Must
1212 * wait until new credentials are committed
1213 * by commit_creds() above
1214 */
1215 if (get_dumpable(current->mm) != SUID_DUMP_USER)
1216 perf_event_exit_task(current);
1217 /*
1218 * cred_guard_mutex must be held at least to this point to prevent
1219 * ptrace_attach() from altering our determination of the task's
1220 * credentials; any time after this it may be unlocked.
1221 */
1222 security_bprm_committed_creds(bprm);
1223 mutex_unlock(&current->signal->cred_guard_mutex);
1224}
1225EXPORT_SYMBOL(install_exec_creds);
1226
1227/*
1228 * determine how safe it is to execute the proposed program
1229 * - the caller must hold ->cred_guard_mutex to protect against
1230 * PTRACE_ATTACH or seccomp thread-sync
1231 */
1232static void check_unsafe_exec(struct linux_binprm *bprm)
1233{
1234 struct task_struct *p = current, *t;
1235 unsigned n_fs;
1236
1237 if (p->ptrace) {
1238 if (p->ptrace & PT_PTRACE_CAP)
1239 bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
1240 else
1241 bprm->unsafe |= LSM_UNSAFE_PTRACE;
1242 }
1243
1244 /*
1245 * This isn't strictly necessary, but it makes it harder for LSMs to
1246 * mess up.
1247 */
1248 if (task_no_new_privs(current))
1249 bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
1250
1251 t = p;
1252 n_fs = 1;
1253 spin_lock(&p->fs->lock);
1254 rcu_read_lock();
1255 while_each_thread(p, t) {
1256 if (t->fs == p->fs)
1257 n_fs++;
1258 }
1259 rcu_read_unlock();
1260
1261 if (p->fs->users > n_fs)
1262 bprm->unsafe |= LSM_UNSAFE_SHARE;
1263 else
1264 p->fs->in_exec = 1;
1265 spin_unlock(&p->fs->lock);
1266}
1267
1268/*
1269 * Fill the binprm structure from the inode.
1270 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
1271 *
1272 * This may be called multiple times for binary chains (scripts for example).
1273 */
1274int prepare_binprm(struct linux_binprm *bprm)
1275{
1276 struct inode *inode = file_inode(bprm->file);
1277 umode_t mode = inode->i_mode;
1278 int retval;
1279
1280
1281 /* clear any previous set[ug]id data from a previous binary */
1282 bprm->cred->euid = current_euid();
1283 bprm->cred->egid = current_egid();
1284
1285 if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) &&
1286 !task_no_new_privs(current) &&
1287 kuid_has_mapping(bprm->cred->user_ns, inode->i_uid) &&
1288 kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) {
1289 /* Set-uid? */
1290 if (mode & S_ISUID) {
1291 bprm->per_clear |= PER_CLEAR_ON_SETID;
1292 bprm->cred->euid = inode->i_uid;
1293 }
1294
1295 /* Set-gid? */
1296 /*
1297 * If setgid is set but no group execute bit then this
1298 * is a candidate for mandatory locking, not a setgid
1299 * executable.
1300 */
1301 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1302 bprm->per_clear |= PER_CLEAR_ON_SETID;
1303 bprm->cred->egid = inode->i_gid;
1304 }
1305 }
1306
1307 /* fill in binprm security blob */
1308 retval = security_bprm_set_creds(bprm);
1309 if (retval)
1310 return retval;
1311 bprm->cred_prepared = 1;
1312
1313 memset(bprm->buf, 0, BINPRM_BUF_SIZE);
1314 return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
1315}
1316
1317EXPORT_SYMBOL(prepare_binprm);
1318
1319/*
1320 * Arguments are '\0' separated strings found at the location bprm->p
1321 * points to; chop off the first by relocating brpm->p to right after
1322 * the first '\0' encountered.
1323 */
1324int remove_arg_zero(struct linux_binprm *bprm)
1325{
1326 int ret = 0;
1327 unsigned long offset;
1328 char *kaddr;
1329 struct page *page;
1330
1331 if (!bprm->argc)
1332 return 0;
1333
1334 do {
1335 offset = bprm->p & ~PAGE_MASK;
1336 page = get_arg_page(bprm, bprm->p, 0);
1337 if (!page) {
1338 ret = -EFAULT;
1339 goto out;
1340 }
1341 kaddr = kmap_atomic(page);
1342
1343 for (; offset < PAGE_SIZE && kaddr[offset];
1344 offset++, bprm->p++)
1345 ;
1346
1347 kunmap_atomic(kaddr);
1348 put_arg_page(page);
1349
1350 if (offset == PAGE_SIZE)
1351 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
1352 } while (offset == PAGE_SIZE);
1353
1354 bprm->p++;
1355 bprm->argc--;
1356 ret = 0;
1357
1358out:
1359 return ret;
1360}
1361EXPORT_SYMBOL(remove_arg_zero);
1362
1363#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1364/*
1365 * cycle the list of binary formats handler, until one recognizes the image
1366 */
1367int search_binary_handler(struct linux_binprm *bprm)
1368{
1369 bool need_retry = IS_ENABLED(CONFIG_MODULES);
1370 struct linux_binfmt *fmt;
1371 int retval;
1372
1373 /* This allows 4 levels of binfmt rewrites before failing hard. */
1374 if (bprm->recursion_depth > 5)
1375 return -ELOOP;
1376
1377 retval = security_bprm_check(bprm);
1378 if (retval)
1379 return retval;
1380
1381 retval = -ENOENT;
1382 retry:
1383 read_lock(&binfmt_lock);
1384 list_for_each_entry(fmt, &formats, lh) {
1385 if (!try_module_get(fmt->module))
1386 continue;
1387 read_unlock(&binfmt_lock);
1388 bprm->recursion_depth++;
1389 retval = fmt->load_binary(bprm);
1390 read_lock(&binfmt_lock);
1391 put_binfmt(fmt);
1392 bprm->recursion_depth--;
1393 if (retval < 0 && !bprm->mm) {
1394 /* we got to flush_old_exec() and failed after it */
1395 read_unlock(&binfmt_lock);
1396 force_sigsegv(SIGSEGV, current);
1397 return retval;
1398 }
1399 if (retval != -ENOEXEC || !bprm->file) {
1400 read_unlock(&binfmt_lock);
1401 return retval;
1402 }
1403 }
1404 read_unlock(&binfmt_lock);
1405
1406 if (need_retry) {
1407 if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
1408 printable(bprm->buf[2]) && printable(bprm->buf[3]))
1409 return retval;
1410 if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
1411 return retval;
1412 need_retry = false;
1413 goto retry;
1414 }
1415
1416 return retval;
1417}
1418EXPORT_SYMBOL(search_binary_handler);
1419
1420static int exec_binprm(struct linux_binprm *bprm)
1421{
1422 pid_t old_pid, old_vpid;
1423 int ret;
1424
1425 /* Need to fetch pid before load_binary changes it */
1426 old_pid = current->pid;
1427 rcu_read_lock();
1428 old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
1429 rcu_read_unlock();
1430
1431 ret = search_binary_handler(bprm);
1432 if (ret >= 0) {
1433 audit_bprm(bprm);
1434 trace_sched_process_exec(current, old_pid, bprm);
1435 ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
1436 proc_exec_connector(current);
1437 }
1438
1439 return ret;
1440}
1441
1442/*
1443 * sys_execve() executes a new program.
1444 */
1445static int do_execveat_common(int fd, struct filename *filename,
1446 struct user_arg_ptr argv,
1447 struct user_arg_ptr envp,
1448 int flags)
1449{
1450 char *pathbuf = NULL;
1451 struct linux_binprm *bprm;
1452 struct file *file;
1453 struct files_struct *displaced;
1454 int retval;
1455
1456 if (IS_ERR(filename))
1457 return PTR_ERR(filename);
1458
1459 /*
1460 * We move the actual failure in case of RLIMIT_NPROC excess from
1461 * set*uid() to execve() because too many poorly written programs
1462 * don't check setuid() return code. Here we additionally recheck
1463 * whether NPROC limit is still exceeded.
1464 */
1465 if ((current->flags & PF_NPROC_EXCEEDED) &&
1466 atomic_read(&current_user()->processes) > rlimit(RLIMIT_NPROC)) {
1467 retval = -EAGAIN;
1468 goto out_ret;
1469 }
1470
1471 /* We're below the limit (still or again), so we don't want to make
1472 * further execve() calls fail. */
1473 current->flags &= ~PF_NPROC_EXCEEDED;
1474
1475 retval = unshare_files(&displaced);
1476 if (retval)
1477 goto out_ret;
1478
1479 retval = -ENOMEM;
1480 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1481 if (!bprm)
1482 goto out_files;
1483
1484 retval = prepare_bprm_creds(bprm);
1485 if (retval)
1486 goto out_free;
1487
1488 check_unsafe_exec(bprm);
1489 current->in_execve = 1;
1490
1491 file = do_open_execat(fd, filename, flags);
1492 retval = PTR_ERR(file);
1493 if (IS_ERR(file))
1494 goto out_unmark;
1495
1496 sched_exec();
1497
1498 bprm->file = file;
1499 if (fd == AT_FDCWD || filename->name[0] == '/') {
1500 bprm->filename = filename->name;
1501 } else {
1502 if (filename->name[0] == '\0')
1503 pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd);
1504 else
1505 pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s",
1506 fd, filename->name);
1507 if (!pathbuf) {
1508 retval = -ENOMEM;
1509 goto out_unmark;
1510 }
1511 /*
1512 * Record that a name derived from an O_CLOEXEC fd will be
1513 * inaccessible after exec. Relies on having exclusive access to
1514 * current->files (due to unshare_files above).
1515 */
1516 if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt)))
1517 bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
1518 bprm->filename = pathbuf;
1519 }
1520 bprm->interp = bprm->filename;
1521
1522 retval = bprm_mm_init(bprm);
1523 if (retval)
1524 goto out_unmark;
1525
1526 bprm->argc = count(argv, MAX_ARG_STRINGS);
1527 if ((retval = bprm->argc) < 0)
1528 goto out;
1529
1530 bprm->envc = count(envp, MAX_ARG_STRINGS);
1531 if ((retval = bprm->envc) < 0)
1532 goto out;
1533
1534 retval = prepare_binprm(bprm);
1535 if (retval < 0)
1536 goto out;
1537
1538 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1539 if (retval < 0)
1540 goto out;
1541
1542 bprm->exec = bprm->p;
1543 retval = copy_strings(bprm->envc, envp, bprm);
1544 if (retval < 0)
1545 goto out;
1546
1547 retval = copy_strings(bprm->argc, argv, bprm);
1548 if (retval < 0)
1549 goto out;
1550
1551 retval = exec_binprm(bprm);
1552 if (retval < 0)
1553 goto out;
1554
1555 /* execve succeeded */
1556 current->fs->in_exec = 0;
1557 current->in_execve = 0;
1558 acct_update_integrals(current);
1559 task_numa_free(current);
1560 free_bprm(bprm);
1561 kfree(pathbuf);
1562 putname(filename);
1563 if (displaced)
1564 put_files_struct(displaced);
1565 return retval;
1566
1567out:
1568 if (bprm->mm) {
1569 acct_arg_size(bprm, 0);
1570 mmput(bprm->mm);
1571 }
1572
1573out_unmark:
1574 current->fs->in_exec = 0;
1575 current->in_execve = 0;
1576
1577out_free:
1578 free_bprm(bprm);
1579 kfree(pathbuf);
1580
1581out_files:
1582 if (displaced)
1583 reset_files_struct(displaced);
1584out_ret:
1585 putname(filename);
1586 return retval;
1587}
1588
1589int do_execve(struct filename *filename,
1590 const char __user *const __user *__argv,
1591 const char __user *const __user *__envp)
1592{
1593 struct user_arg_ptr argv = { .ptr.native = __argv };
1594 struct user_arg_ptr envp = { .ptr.native = __envp };
1595 return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
1596}
1597
1598int do_execveat(int fd, struct filename *filename,
1599 const char __user *const __user *__argv,
1600 const char __user *const __user *__envp,
1601 int flags)
1602{
1603 struct user_arg_ptr argv = { .ptr.native = __argv };
1604 struct user_arg_ptr envp = { .ptr.native = __envp };
1605
1606 return do_execveat_common(fd, filename, argv, envp, flags);
1607}
1608
1609#ifdef CONFIG_COMPAT
1610static int compat_do_execve(struct filename *filename,
1611 const compat_uptr_t __user *__argv,
1612 const compat_uptr_t __user *__envp)
1613{
1614 struct user_arg_ptr argv = {
1615 .is_compat = true,
1616 .ptr.compat = __argv,
1617 };
1618 struct user_arg_ptr envp = {
1619 .is_compat = true,
1620 .ptr.compat = __envp,
1621 };
1622 return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
1623}
1624
1625static int compat_do_execveat(int fd, struct filename *filename,
1626 const compat_uptr_t __user *__argv,
1627 const compat_uptr_t __user *__envp,
1628 int flags)
1629{
1630 struct user_arg_ptr argv = {
1631 .is_compat = true,
1632 .ptr.compat = __argv,
1633 };
1634 struct user_arg_ptr envp = {
1635 .is_compat = true,
1636 .ptr.compat = __envp,
1637 };
1638 return do_execveat_common(fd, filename, argv, envp, flags);
1639}
1640#endif
1641
1642void set_binfmt(struct linux_binfmt *new)
1643{
1644 struct mm_struct *mm = current->mm;
1645
1646 if (mm->binfmt)
1647 module_put(mm->binfmt->module);
1648
1649 mm->binfmt = new;
1650 if (new)
1651 __module_get(new->module);
1652}
1653EXPORT_SYMBOL(set_binfmt);
1654
1655/*
1656 * set_dumpable stores three-value SUID_DUMP_* into mm->flags.
1657 */
1658void set_dumpable(struct mm_struct *mm, int value)
1659{
1660 unsigned long old, new;
1661
1662 if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
1663 return;
1664
1665 do {
1666 old = ACCESS_ONCE(mm->flags);
1667 new = (old & ~MMF_DUMPABLE_MASK) | value;
1668 } while (cmpxchg(&mm->flags, old, new) != old);
1669}
1670
1671SYSCALL_DEFINE3(execve,
1672 const char __user *, filename,
1673 const char __user *const __user *, argv,
1674 const char __user *const __user *, envp)
1675{
1676 return do_execve(getname(filename), argv, envp);
1677}
1678
1679SYSCALL_DEFINE5(execveat,
1680 int, fd, const char __user *, filename,
1681 const char __user *const __user *, argv,
1682 const char __user *const __user *, envp,
1683 int, flags)
1684{
1685 int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
1686
1687 return do_execveat(fd,
1688 getname_flags(filename, lookup_flags, NULL),
1689 argv, envp, flags);
1690}
1691
1692#ifdef CONFIG_COMPAT
1693COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
1694 const compat_uptr_t __user *, argv,
1695 const compat_uptr_t __user *, envp)
1696{
1697 return compat_do_execve(getname(filename), argv, envp);
1698}
1699
1700COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
1701 const char __user *, filename,
1702 const compat_uptr_t __user *, argv,
1703 const compat_uptr_t __user *, envp,
1704 int, flags)
1705{
1706 int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
1707
1708 return compat_do_execveat(fd,
1709 getname_flags(filename, lookup_flags, NULL),
1710 argv, envp, flags);
1711}
1712#endif