projects/linux·blob v3.17-rc4 · refs

1613 lines · 37.3 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 up_write(&mm->mmap_sem);
281 bprm->p = vma->vm_end - sizeof(void *);
282 return 0;
283err:
284 up_write(&mm->mmap_sem);
285 bprm->vma = NULL;
286 kmem_cache_free(vm_area_cachep, vma);
287 return err;
288}
289
290static bool valid_arg_len(struct linux_binprm *bprm, long len)
291{
292 return len <= MAX_ARG_STRLEN;
293}
294
295#else
296
297static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
298{
299}
300
301static 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
317static void put_arg_page(struct page *page)
318{
319}
320
321static 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
329static 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
337static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
338 struct page *page)
339{
340}
341
342static int __bprm_mm_init(struct linux_binprm *bprm)
343{
344 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
345 return 0;
346}
347
348static 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 */
361static 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
377err:
378 if (mm) {
379 bprm->mm = NULL;
380 mmdrop(mm);
381 }
382
383 return err;
384}
385
386struct 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
398static 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 */
422static 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 */
453static 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;
532out:
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 */
544int 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}
559EXPORT_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 */
575static 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 */
640int 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
742out_unlock:
743 up_write(&mm->mmap_sem);
744 return ret;
745}
746EXPORT_SYMBOL(setup_arg_pages);
747
748#endif /* CONFIG_MMU */
749
750static 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
778out:
779 return file;
780
781exit:
782 fput(file);
783 return ERR_PTR(err);
784}
785
786struct file *open_exec(const char *name)
787{
788 struct filename tmp = { .name = name };
789 return do_open_exec(&tmp);
790}
791EXPORT_SYMBOL(open_exec);
792
793int 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
808EXPORT_SYMBOL(kernel_read);
809
810ssize_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}
817EXPORT_SYMBOL(read_code);
818
819static 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 */
869static 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
988no_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
1021killed:
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
1030char *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}
1038EXPORT_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
1045void __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
1054int 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
1085out:
1086 return retval;
1087}
1088EXPORT_SYMBOL(flush_old_exec);
1089
1090void 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}
1095EXPORT_SYMBOL(would_dump);
1096
1097void 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}
1134EXPORT_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 */
1142int prepare_bprm_creds(struct linux_binprm *bprm)
1143{
1144 if (mutex_lock_interruptible(&current->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(&current->signal->cred_guard_mutex);
1152 return -ENOMEM;
1153}
1154
1155static void free_bprm(struct linux_binprm *bprm)
1156{
1157 free_arg_pages(bprm);
1158 if (bprm->cred) {
1159 mutex_unlock(&current->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
1172int 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}
1182EXPORT_SYMBOL(bprm_change_interp);
1183
1184/*
1185 * install the new credentials for this executable
1186 */
1187void 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(&current->signal->cred_guard_mutex);
1209}
1210EXPORT_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 */
1217static 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 */
1259int 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
1302EXPORT_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 */
1309int 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
1343out:
1344 return ret;
1345}
1346EXPORT_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 */
1352int 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 bprm->recursion_depth--;
1376 if (retval >= 0 || retval != -ENOEXEC ||
1377 bprm->mm == NULL || bprm->file == NULL) {
1378 put_binfmt(fmt);
1379 return retval;
1380 }
1381 read_lock(&binfmt_lock);
1382 put_binfmt(fmt);
1383 }
1384 read_unlock(&binfmt_lock);
1385
1386 if (need_retry && retval == -ENOEXEC) {
1387 if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
1388 printable(bprm->buf[2]) && printable(bprm->buf[3]))
1389 return retval;
1390 if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
1391 return retval;
1392 need_retry = false;
1393 goto retry;
1394 }
1395
1396 return retval;
1397}
1398EXPORT_SYMBOL(search_binary_handler);
1399
1400static int exec_binprm(struct linux_binprm *bprm)
1401{
1402 pid_t old_pid, old_vpid;
1403 int ret;
1404
1405 /* Need to fetch pid before load_binary changes it */
1406 old_pid = current->pid;
1407 rcu_read_lock();
1408 old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
1409 rcu_read_unlock();
1410
1411 ret = search_binary_handler(bprm);
1412 if (ret >= 0) {
1413 audit_bprm(bprm);
1414 trace_sched_process_exec(current, old_pid, bprm);
1415 ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
1416 proc_exec_connector(current);
1417 }
1418
1419 return ret;
1420}
1421
1422/*
1423 * sys_execve() executes a new program.
1424 */
1425static int do_execve_common(struct filename *filename,
1426 struct user_arg_ptr argv,
1427 struct user_arg_ptr envp)
1428{
1429 struct linux_binprm *bprm;
1430 struct file *file;
1431 struct files_struct *displaced;
1432 int retval;
1433
1434 if (IS_ERR(filename))
1435 return PTR_ERR(filename);
1436
1437 /*
1438 * We move the actual failure in case of RLIMIT_NPROC excess from
1439 * set*uid() to execve() because too many poorly written programs
1440 * don't check setuid() return code. Here we additionally recheck
1441 * whether NPROC limit is still exceeded.
1442 */
1443 if ((current->flags & PF_NPROC_EXCEEDED) &&
1444 atomic_read(&current_user()->processes) > rlimit(RLIMIT_NPROC)) {
1445 retval = -EAGAIN;
1446 goto out_ret;
1447 }
1448
1449 /* We're below the limit (still or again), so we don't want to make
1450 * further execve() calls fail. */
1451 current->flags &= ~PF_NPROC_EXCEEDED;
1452
1453 retval = unshare_files(&displaced);
1454 if (retval)
1455 goto out_ret;
1456
1457 retval = -ENOMEM;
1458 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1459 if (!bprm)
1460 goto out_files;
1461
1462 retval = prepare_bprm_creds(bprm);
1463 if (retval)
1464 goto out_free;
1465
1466 check_unsafe_exec(bprm);
1467 current->in_execve = 1;
1468
1469 file = do_open_exec(filename);
1470 retval = PTR_ERR(file);
1471 if (IS_ERR(file))
1472 goto out_unmark;
1473
1474 sched_exec();
1475
1476 bprm->file = file;
1477 bprm->filename = bprm->interp = filename->name;
1478
1479 retval = bprm_mm_init(bprm);
1480 if (retval)
1481 goto out_unmark;
1482
1483 bprm->argc = count(argv, MAX_ARG_STRINGS);
1484 if ((retval = bprm->argc) < 0)
1485 goto out;
1486
1487 bprm->envc = count(envp, MAX_ARG_STRINGS);
1488 if ((retval = bprm->envc) < 0)
1489 goto out;
1490
1491 retval = prepare_binprm(bprm);
1492 if (retval < 0)
1493 goto out;
1494
1495 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1496 if (retval < 0)
1497 goto out;
1498
1499 bprm->exec = bprm->p;
1500 retval = copy_strings(bprm->envc, envp, bprm);
1501 if (retval < 0)
1502 goto out;
1503
1504 retval = copy_strings(bprm->argc, argv, bprm);
1505 if (retval < 0)
1506 goto out;
1507
1508 retval = exec_binprm(bprm);
1509 if (retval < 0)
1510 goto out;
1511
1512 /* execve succeeded */
1513 current->fs->in_exec = 0;
1514 current->in_execve = 0;
1515 acct_update_integrals(current);
1516 task_numa_free(current);
1517 free_bprm(bprm);
1518 putname(filename);
1519 if (displaced)
1520 put_files_struct(displaced);
1521 return retval;
1522
1523out:
1524 if (bprm->mm) {
1525 acct_arg_size(bprm, 0);
1526 mmput(bprm->mm);
1527 }
1528
1529out_unmark:
1530 current->fs->in_exec = 0;
1531 current->in_execve = 0;
1532
1533out_free:
1534 free_bprm(bprm);
1535
1536out_files:
1537 if (displaced)
1538 reset_files_struct(displaced);
1539out_ret:
1540 putname(filename);
1541 return retval;
1542}
1543
1544int do_execve(struct filename *filename,
1545 const char __user *const __user *__argv,
1546 const char __user *const __user *__envp)
1547{
1548 struct user_arg_ptr argv = { .ptr.native = __argv };
1549 struct user_arg_ptr envp = { .ptr.native = __envp };
1550 return do_execve_common(filename, argv, envp);
1551}
1552
1553#ifdef CONFIG_COMPAT
1554static int compat_do_execve(struct filename *filename,
1555 const compat_uptr_t __user *__argv,
1556 const compat_uptr_t __user *__envp)
1557{
1558 struct user_arg_ptr argv = {
1559 .is_compat = true,
1560 .ptr.compat = __argv,
1561 };
1562 struct user_arg_ptr envp = {
1563 .is_compat = true,
1564 .ptr.compat = __envp,
1565 };
1566 return do_execve_common(filename, argv, envp);
1567}
1568#endif
1569
1570void set_binfmt(struct linux_binfmt *new)
1571{
1572 struct mm_struct *mm = current->mm;
1573
1574 if (mm->binfmt)
1575 module_put(mm->binfmt->module);
1576
1577 mm->binfmt = new;
1578 if (new)
1579 __module_get(new->module);
1580}
1581EXPORT_SYMBOL(set_binfmt);
1582
1583/*
1584 * set_dumpable stores three-value SUID_DUMP_* into mm->flags.
1585 */
1586void set_dumpable(struct mm_struct *mm, int value)
1587{
1588 unsigned long old, new;
1589
1590 if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
1591 return;
1592
1593 do {
1594 old = ACCESS_ONCE(mm->flags);
1595 new = (old & ~MMF_DUMPABLE_MASK) | value;
1596 } while (cmpxchg(&mm->flags, old, new) != old);
1597}
1598
1599SYSCALL_DEFINE3(execve,
1600 const char __user *, filename,
1601 const char __user *const __user *, argv,
1602 const char __user *const __user *, envp)
1603{
1604 return do_execve(getname(filename), argv, envp);
1605}
1606#ifdef CONFIG_COMPAT
1607COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
1608 const compat_uptr_t __user *, argv,
1609 const compat_uptr_t __user *, envp)
1610{
1611 return compat_do_execve(getname(filename), argv, envp);
1612}
1613#endif