4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * #!-checking implemented by tytso.
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.
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.
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
25 #include <linux/slab.h>
26 #include <linux/file.h>
27 #include <linux/fdtable.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 #include <linux/vmalloc.h>
61 #include <asm/uaccess.h>
62 #include <asm/mmu_context.h>
65 #include <trace/events/task.h>
68 #include <trace/events/sched.h>
70 int suid_dumpable
= 0;
72 static LIST_HEAD(formats
);
73 static DEFINE_RWLOCK(binfmt_lock
);
75 void __register_binfmt(struct linux_binfmt
* fmt
, int insert
)
78 if (WARN_ON(!fmt
->load_binary
))
80 write_lock(&binfmt_lock
);
81 insert
? list_add(&fmt
->lh
, &formats
) :
82 list_add_tail(&fmt
->lh
, &formats
);
83 write_unlock(&binfmt_lock
);
86 EXPORT_SYMBOL(__register_binfmt
);
88 void unregister_binfmt(struct linux_binfmt
* fmt
)
90 write_lock(&binfmt_lock
);
92 write_unlock(&binfmt_lock
);
95 EXPORT_SYMBOL(unregister_binfmt
);
97 static inline void put_binfmt(struct linux_binfmt
* fmt
)
99 module_put(fmt
->module
);
102 bool path_noexec(const struct path
*path
)
104 return (path
->mnt
->mnt_flags
& MNT_NOEXEC
) ||
105 (path
->mnt
->mnt_sb
->s_iflags
& SB_I_NOEXEC
);
110 * Note that a shared library must be both readable and executable due to
113 * Also note that we take the address to load from from the file itself.
115 SYSCALL_DEFINE1(uselib
, const char __user
*, library
)
117 struct linux_binfmt
*fmt
;
119 struct filename
*tmp
= getname(library
);
120 int error
= PTR_ERR(tmp
);
121 static const struct open_flags uselib_flags
= {
122 .open_flag
= O_LARGEFILE
| O_RDONLY
| __FMODE_EXEC
,
123 .acc_mode
= MAY_READ
| MAY_EXEC
,
124 .intent
= LOOKUP_OPEN
,
125 .lookup_flags
= LOOKUP_FOLLOW
,
131 file
= do_filp_open(AT_FDCWD
, tmp
, &uselib_flags
);
133 error
= PTR_ERR(file
);
138 if (!S_ISREG(file_inode(file
)->i_mode
))
142 if (path_noexec(&file
->f_path
))
149 read_lock(&binfmt_lock
);
150 list_for_each_entry(fmt
, &formats
, lh
) {
151 if (!fmt
->load_shlib
)
153 if (!try_module_get(fmt
->module
))
155 read_unlock(&binfmt_lock
);
156 error
= fmt
->load_shlib(file
);
157 read_lock(&binfmt_lock
);
159 if (error
!= -ENOEXEC
)
162 read_unlock(&binfmt_lock
);
168 #endif /* #ifdef CONFIG_USELIB */
172 * The nascent bprm->mm is not visible until exec_mmap() but it can
173 * use a lot of memory, account these pages in current->mm temporary
174 * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
175 * change the counter back via acct_arg_size(0).
177 static void acct_arg_size(struct linux_binprm
*bprm
, unsigned long pages
)
179 struct mm_struct
*mm
= current
->mm
;
180 long diff
= (long)(pages
- bprm
->vma_pages
);
185 bprm
->vma_pages
= pages
;
186 add_mm_counter(mm
, MM_ANONPAGES
, diff
);
189 static struct page
*get_arg_page(struct linux_binprm
*bprm
, unsigned long pos
,
195 #ifdef CONFIG_STACK_GROWSUP
197 ret
= expand_downwards(bprm
->vma
, pos
);
202 ret
= get_user_pages(current
, bprm
->mm
, pos
,
203 1, write
, 1, &page
, NULL
);
208 unsigned long size
= bprm
->vma
->vm_end
- bprm
->vma
->vm_start
;
211 acct_arg_size(bprm
, size
/ PAGE_SIZE
);
214 * We've historically supported up to 32 pages (ARG_MAX)
215 * of argument strings even with small stacks
221 * Limit to 1/4-th the stack size for the argv+env strings.
223 * - the remaining binfmt code will not run out of stack space,
224 * - the program will have a reasonable amount of stack left
227 rlim
= current
->signal
->rlim
;
228 if (size
> ACCESS_ONCE(rlim
[RLIMIT_STACK
].rlim_cur
) / 4) {
237 static void put_arg_page(struct page
*page
)
242 static void free_arg_page(struct linux_binprm
*bprm
, int i
)
246 static void free_arg_pages(struct linux_binprm
*bprm
)
250 static void flush_arg_page(struct linux_binprm
*bprm
, unsigned long pos
,
253 flush_cache_page(bprm
->vma
, pos
, page_to_pfn(page
));
256 static int __bprm_mm_init(struct linux_binprm
*bprm
)
259 struct vm_area_struct
*vma
= NULL
;
260 struct mm_struct
*mm
= bprm
->mm
;
262 bprm
->vma
= vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
266 down_write(&mm
->mmap_sem
);
270 * Place the stack at the largest stack address the architecture
271 * supports. Later, we'll move this to an appropriate place. We don't
272 * use STACK_TOP because that can depend on attributes which aren't
275 BUILD_BUG_ON(VM_STACK_FLAGS
& VM_STACK_INCOMPLETE_SETUP
);
276 vma
->vm_end
= STACK_TOP_MAX
;
277 vma
->vm_start
= vma
->vm_end
- PAGE_SIZE
;
278 vma
->vm_flags
= VM_SOFTDIRTY
| VM_STACK_FLAGS
| VM_STACK_INCOMPLETE_SETUP
;
279 vma
->vm_page_prot
= vm_get_page_prot(vma
->vm_flags
);
280 INIT_LIST_HEAD(&vma
->anon_vma_chain
);
282 err
= insert_vm_struct(mm
, vma
);
286 mm
->stack_vm
= mm
->total_vm
= 1;
287 arch_bprm_mm_init(mm
, vma
);
288 up_write(&mm
->mmap_sem
);
289 bprm
->p
= vma
->vm_end
- sizeof(void *);
292 up_write(&mm
->mmap_sem
);
294 kmem_cache_free(vm_area_cachep
, vma
);
298 static bool valid_arg_len(struct linux_binprm
*bprm
, long len
)
300 return len
<= MAX_ARG_STRLEN
;
305 static inline void acct_arg_size(struct linux_binprm
*bprm
, unsigned long pages
)
309 static struct page
*get_arg_page(struct linux_binprm
*bprm
, unsigned long pos
,
314 page
= bprm
->page
[pos
/ PAGE_SIZE
];
315 if (!page
&& write
) {
316 page
= alloc_page(GFP_HIGHUSER
|__GFP_ZERO
);
319 bprm
->page
[pos
/ PAGE_SIZE
] = page
;
325 static void put_arg_page(struct page
*page
)
329 static void free_arg_page(struct linux_binprm
*bprm
, int i
)
332 __free_page(bprm
->page
[i
]);
333 bprm
->page
[i
] = NULL
;
337 static void free_arg_pages(struct linux_binprm
*bprm
)
341 for (i
= 0; i
< MAX_ARG_PAGES
; i
++)
342 free_arg_page(bprm
, i
);
345 static void flush_arg_page(struct linux_binprm
*bprm
, unsigned long pos
,
350 static int __bprm_mm_init(struct linux_binprm
*bprm
)
352 bprm
->p
= PAGE_SIZE
* MAX_ARG_PAGES
- sizeof(void *);
356 static bool valid_arg_len(struct linux_binprm
*bprm
, long len
)
358 return len
<= bprm
->p
;
361 #endif /* CONFIG_MMU */
364 * Create a new mm_struct and populate it with a temporary stack
365 * vm_area_struct. We don't have enough context at this point to set the stack
366 * flags, permissions, and offset, so we use temporary values. We'll update
367 * them later in setup_arg_pages().
369 static int bprm_mm_init(struct linux_binprm
*bprm
)
372 struct mm_struct
*mm
= NULL
;
374 bprm
->mm
= mm
= mm_alloc();
379 err
= __bprm_mm_init(bprm
);
394 struct user_arg_ptr
{
399 const char __user
*const __user
*native
;
401 const compat_uptr_t __user
*compat
;
406 static const char __user
*get_user_arg_ptr(struct user_arg_ptr argv
, int nr
)
408 const char __user
*native
;
411 if (unlikely(argv
.is_compat
)) {
412 compat_uptr_t compat
;
414 if (get_user(compat
, argv
.ptr
.compat
+ nr
))
415 return ERR_PTR(-EFAULT
);
417 return compat_ptr(compat
);
421 if (get_user(native
, argv
.ptr
.native
+ nr
))
422 return ERR_PTR(-EFAULT
);
428 * count() counts the number of strings in array ARGV.
430 static int count(struct user_arg_ptr argv
, int max
)
434 if (argv
.ptr
.native
!= NULL
) {
436 const char __user
*p
= get_user_arg_ptr(argv
, i
);
448 if (fatal_signal_pending(current
))
449 return -ERESTARTNOHAND
;
457 * 'copy_strings()' copies argument/environment strings from the old
458 * processes's memory to the new process's stack. The call to get_user_pages()
459 * ensures the destination page is created and not swapped out.
461 static int copy_strings(int argc
, struct user_arg_ptr argv
,
462 struct linux_binprm
*bprm
)
464 struct page
*kmapped_page
= NULL
;
466 unsigned long kpos
= 0;
470 const char __user
*str
;
475 str
= get_user_arg_ptr(argv
, argc
);
479 len
= strnlen_user(str
, MAX_ARG_STRLEN
);
484 if (!valid_arg_len(bprm
, len
))
487 /* We're going to work our way backwords. */
493 int offset
, bytes_to_copy
;
495 if (fatal_signal_pending(current
)) {
496 ret
= -ERESTARTNOHAND
;
501 offset
= pos
% PAGE_SIZE
;
505 bytes_to_copy
= offset
;
506 if (bytes_to_copy
> len
)
509 offset
-= bytes_to_copy
;
510 pos
-= bytes_to_copy
;
511 str
-= bytes_to_copy
;
512 len
-= bytes_to_copy
;
514 if (!kmapped_page
|| kpos
!= (pos
& PAGE_MASK
)) {
517 page
= get_arg_page(bprm
, pos
, 1);
524 flush_kernel_dcache_page(kmapped_page
);
525 kunmap(kmapped_page
);
526 put_arg_page(kmapped_page
);
529 kaddr
= kmap(kmapped_page
);
530 kpos
= pos
& PAGE_MASK
;
531 flush_arg_page(bprm
, kpos
, kmapped_page
);
533 if (copy_from_user(kaddr
+offset
, str
, bytes_to_copy
)) {
542 flush_kernel_dcache_page(kmapped_page
);
543 kunmap(kmapped_page
);
544 put_arg_page(kmapped_page
);
550 * Like copy_strings, but get argv and its values from kernel memory.
552 int copy_strings_kernel(int argc
, const char *const *__argv
,
553 struct linux_binprm
*bprm
)
556 mm_segment_t oldfs
= get_fs();
557 struct user_arg_ptr argv
= {
558 .ptr
.native
= (const char __user
*const __user
*)__argv
,
562 r
= copy_strings(argc
, argv
, bprm
);
567 EXPORT_SYMBOL(copy_strings_kernel
);
572 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
573 * the binfmt code determines where the new stack should reside, we shift it to
574 * its final location. The process proceeds as follows:
576 * 1) Use shift to calculate the new vma endpoints.
577 * 2) Extend vma to cover both the old and new ranges. This ensures the
578 * arguments passed to subsequent functions are consistent.
579 * 3) Move vma's page tables to the new range.
580 * 4) Free up any cleared pgd range.
581 * 5) Shrink the vma to cover only the new range.
583 static int shift_arg_pages(struct vm_area_struct
*vma
, unsigned long shift
)
585 struct mm_struct
*mm
= vma
->vm_mm
;
586 unsigned long old_start
= vma
->vm_start
;
587 unsigned long old_end
= vma
->vm_end
;
588 unsigned long length
= old_end
- old_start
;
589 unsigned long new_start
= old_start
- shift
;
590 unsigned long new_end
= old_end
- shift
;
591 struct mmu_gather tlb
;
593 BUG_ON(new_start
> new_end
);
596 * ensure there are no vmas between where we want to go
599 if (vma
!= find_vma(mm
, new_start
))
603 * cover the whole range: [new_start, old_end)
605 if (vma_adjust(vma
, new_start
, old_end
, vma
->vm_pgoff
, NULL
))
609 * move the page tables downwards, on failure we rely on
610 * process cleanup to remove whatever mess we made.
612 if (length
!= move_page_tables(vma
, old_start
,
613 vma
, new_start
, length
, false))
617 tlb_gather_mmu(&tlb
, mm
, old_start
, old_end
);
618 if (new_end
> old_start
) {
620 * when the old and new regions overlap clear from new_end.
622 free_pgd_range(&tlb
, new_end
, old_end
, new_end
,
623 vma
->vm_next
? vma
->vm_next
->vm_start
: USER_PGTABLES_CEILING
);
626 * otherwise, clean from old_start; this is done to not touch
627 * the address space in [new_end, old_start) some architectures
628 * have constraints on va-space that make this illegal (IA64) -
629 * for the others its just a little faster.
631 free_pgd_range(&tlb
, old_start
, old_end
, new_end
,
632 vma
->vm_next
? vma
->vm_next
->vm_start
: USER_PGTABLES_CEILING
);
634 tlb_finish_mmu(&tlb
, old_start
, old_end
);
637 * Shrink the vma to just the new range. Always succeeds.
639 vma_adjust(vma
, new_start
, new_end
, vma
->vm_pgoff
, NULL
);
645 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
646 * the stack is optionally relocated, and some extra space is added.
648 int setup_arg_pages(struct linux_binprm
*bprm
,
649 unsigned long stack_top
,
650 int executable_stack
)
653 unsigned long stack_shift
;
654 struct mm_struct
*mm
= current
->mm
;
655 struct vm_area_struct
*vma
= bprm
->vma
;
656 struct vm_area_struct
*prev
= NULL
;
657 unsigned long vm_flags
;
658 unsigned long stack_base
;
659 unsigned long stack_size
;
660 unsigned long stack_expand
;
661 unsigned long rlim_stack
;
663 #ifdef CONFIG_STACK_GROWSUP
664 /* Limit stack size */
665 stack_base
= rlimit_max(RLIMIT_STACK
);
666 if (stack_base
> STACK_SIZE_MAX
)
667 stack_base
= STACK_SIZE_MAX
;
669 /* Add space for stack randomization. */
670 stack_base
+= (STACK_RND_MASK
<< PAGE_SHIFT
);
672 /* Make sure we didn't let the argument array grow too large. */
673 if (vma
->vm_end
- vma
->vm_start
> stack_base
)
676 stack_base
= PAGE_ALIGN(stack_top
- stack_base
);
678 stack_shift
= vma
->vm_start
- stack_base
;
679 mm
->arg_start
= bprm
->p
- stack_shift
;
680 bprm
->p
= vma
->vm_end
- stack_shift
;
682 stack_top
= arch_align_stack(stack_top
);
683 stack_top
= PAGE_ALIGN(stack_top
);
685 if (unlikely(stack_top
< mmap_min_addr
) ||
686 unlikely(vma
->vm_end
- vma
->vm_start
>= stack_top
- mmap_min_addr
))
689 stack_shift
= vma
->vm_end
- stack_top
;
691 bprm
->p
-= stack_shift
;
692 mm
->arg_start
= bprm
->p
;
696 bprm
->loader
-= stack_shift
;
697 bprm
->exec
-= stack_shift
;
699 down_write(&mm
->mmap_sem
);
700 vm_flags
= VM_STACK_FLAGS
;
703 * Adjust stack execute permissions; explicitly enable for
704 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
705 * (arch default) otherwise.
707 if (unlikely(executable_stack
== EXSTACK_ENABLE_X
))
709 else if (executable_stack
== EXSTACK_DISABLE_X
)
710 vm_flags
&= ~VM_EXEC
;
711 vm_flags
|= mm
->def_flags
;
712 vm_flags
|= VM_STACK_INCOMPLETE_SETUP
;
714 ret
= mprotect_fixup(vma
, &prev
, vma
->vm_start
, vma
->vm_end
,
720 /* Move stack pages down in memory. */
722 ret
= shift_arg_pages(vma
, stack_shift
);
727 /* mprotect_fixup is overkill to remove the temporary stack flags */
728 vma
->vm_flags
&= ~VM_STACK_INCOMPLETE_SETUP
;
730 stack_expand
= 131072UL; /* randomly 32*4k (or 2*64k) pages */
731 stack_size
= vma
->vm_end
- vma
->vm_start
;
733 * Align this down to a page boundary as expand_stack
736 rlim_stack
= rlimit(RLIMIT_STACK
) & PAGE_MASK
;
737 #ifdef CONFIG_STACK_GROWSUP
738 if (stack_size
+ stack_expand
> rlim_stack
)
739 stack_base
= vma
->vm_start
+ rlim_stack
;
741 stack_base
= vma
->vm_end
+ stack_expand
;
743 if (stack_size
+ stack_expand
> rlim_stack
)
744 stack_base
= vma
->vm_end
- rlim_stack
;
746 stack_base
= vma
->vm_start
- stack_expand
;
748 current
->mm
->start_stack
= bprm
->p
;
749 ret
= expand_stack(vma
, stack_base
);
754 up_write(&mm
->mmap_sem
);
757 EXPORT_SYMBOL(setup_arg_pages
);
759 #endif /* CONFIG_MMU */
761 static struct file
*do_open_execat(int fd
, struct filename
*name
, int flags
)
765 struct open_flags open_exec_flags
= {
766 .open_flag
= O_LARGEFILE
| O_RDONLY
| __FMODE_EXEC
,
767 .acc_mode
= MAY_EXEC
,
768 .intent
= LOOKUP_OPEN
,
769 .lookup_flags
= LOOKUP_FOLLOW
,
772 if ((flags
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)) != 0)
773 return ERR_PTR(-EINVAL
);
774 if (flags
& AT_SYMLINK_NOFOLLOW
)
775 open_exec_flags
.lookup_flags
&= ~LOOKUP_FOLLOW
;
776 if (flags
& AT_EMPTY_PATH
)
777 open_exec_flags
.lookup_flags
|= LOOKUP_EMPTY
;
779 file
= do_filp_open(fd
, name
, &open_exec_flags
);
784 if (!S_ISREG(file_inode(file
)->i_mode
))
787 if (path_noexec(&file
->f_path
))
790 err
= deny_write_access(file
);
794 if (name
->name
[0] != '\0')
805 struct file
*open_exec(const char *name
)
807 struct filename
*filename
= getname_kernel(name
);
808 struct file
*f
= ERR_CAST(filename
);
810 if (!IS_ERR(filename
)) {
811 f
= do_open_execat(AT_FDCWD
, filename
, 0);
816 EXPORT_SYMBOL(open_exec
);
818 int kernel_read(struct file
*file
, loff_t offset
,
819 char *addr
, unsigned long count
)
827 /* The cast to a user pointer is valid due to the set_fs() */
828 result
= vfs_read(file
, (void __user
*)addr
, count
, &pos
);
833 EXPORT_SYMBOL(kernel_read
);
835 int kernel_read_file(struct file
*file
, void **buf
, loff_t
*size
,
836 loff_t max_size
, enum kernel_read_file_id id
)
842 if (!S_ISREG(file_inode(file
)->i_mode
) || max_size
< 0)
845 ret
= security_kernel_read_file(file
, id
);
849 i_size
= i_size_read(file_inode(file
));
850 if (max_size
> 0 && i_size
> max_size
)
855 *buf
= vmalloc(i_size
);
860 while (pos
< i_size
) {
861 bytes
= kernel_read(file
, pos
, (char *)(*buf
) + pos
,
878 ret
= security_kernel_post_read_file(file
, *buf
, i_size
, id
);
889 EXPORT_SYMBOL_GPL(kernel_read_file
);
891 int kernel_read_file_from_path(char *path
, void **buf
, loff_t
*size
,
892 loff_t max_size
, enum kernel_read_file_id id
)
900 file
= filp_open(path
, O_RDONLY
, 0);
902 return PTR_ERR(file
);
904 ret
= kernel_read_file(file
, buf
, size
, max_size
, id
);
908 EXPORT_SYMBOL_GPL(kernel_read_file_from_path
);
910 int kernel_read_file_from_fd(int fd
, void **buf
, loff_t
*size
, loff_t max_size
,
911 enum kernel_read_file_id id
)
913 struct fd f
= fdget(fd
);
919 ret
= kernel_read_file(f
.file
, buf
, size
, max_size
, id
);
924 EXPORT_SYMBOL_GPL(kernel_read_file_from_fd
);
926 ssize_t
read_code(struct file
*file
, unsigned long addr
, loff_t pos
, size_t len
)
928 ssize_t res
= vfs_read(file
, (void __user
*)addr
, len
, &pos
);
930 flush_icache_range(addr
, addr
+ len
);
933 EXPORT_SYMBOL(read_code
);
935 static int exec_mmap(struct mm_struct
*mm
)
937 struct task_struct
*tsk
;
938 struct mm_struct
*old_mm
, *active_mm
;
940 /* Notify parent that we're no longer interested in the old VM */
942 old_mm
= current
->mm
;
943 mm_release(tsk
, old_mm
);
948 * Make sure that if there is a core dump in progress
949 * for the old mm, we get out and die instead of going
950 * through with the exec. We must hold mmap_sem around
951 * checking core_state and changing tsk->mm.
953 down_read(&old_mm
->mmap_sem
);
954 if (unlikely(old_mm
->core_state
)) {
955 up_read(&old_mm
->mmap_sem
);
960 active_mm
= tsk
->active_mm
;
963 activate_mm(active_mm
, mm
);
964 tsk
->mm
->vmacache_seqnum
= 0;
968 up_read(&old_mm
->mmap_sem
);
969 BUG_ON(active_mm
!= old_mm
);
970 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, old_mm
);
971 mm_update_next_owner(old_mm
);
980 * This function makes sure the current process has its own signal table,
981 * so that flush_signal_handlers can later reset the handlers without
982 * disturbing other processes. (Other processes might share the signal
983 * table via the CLONE_SIGHAND option to clone().)
985 static int de_thread(struct task_struct
*tsk
)
987 struct signal_struct
*sig
= tsk
->signal
;
988 struct sighand_struct
*oldsighand
= tsk
->sighand
;
989 spinlock_t
*lock
= &oldsighand
->siglock
;
991 if (thread_group_empty(tsk
))
992 goto no_thread_group
;
995 * Kill all other threads in the thread group.
998 if (signal_group_exit(sig
)) {
1000 * Another group action in progress, just
1001 * return so that the signal is processed.
1003 spin_unlock_irq(lock
);
1007 sig
->group_exit_task
= tsk
;
1008 sig
->notify_count
= zap_other_threads(tsk
);
1009 if (!thread_group_leader(tsk
))
1010 sig
->notify_count
--;
1012 while (sig
->notify_count
) {
1013 __set_current_state(TASK_KILLABLE
);
1014 spin_unlock_irq(lock
);
1016 if (unlikely(__fatal_signal_pending(tsk
)))
1018 spin_lock_irq(lock
);
1020 spin_unlock_irq(lock
);
1023 * At this point all other threads have exited, all we have to
1024 * do is to wait for the thread group leader to become inactive,
1025 * and to assume its PID:
1027 if (!thread_group_leader(tsk
)) {
1028 struct task_struct
*leader
= tsk
->group_leader
;
1031 threadgroup_change_begin(tsk
);
1032 write_lock_irq(&tasklist_lock
);
1034 * Do this under tasklist_lock to ensure that
1035 * exit_notify() can't miss ->group_exit_task
1037 sig
->notify_count
= -1;
1038 if (likely(leader
->exit_state
))
1040 __set_current_state(TASK_KILLABLE
);
1041 write_unlock_irq(&tasklist_lock
);
1042 threadgroup_change_end(tsk
);
1044 if (unlikely(__fatal_signal_pending(tsk
)))
1049 * The only record we have of the real-time age of a
1050 * process, regardless of execs it's done, is start_time.
1051 * All the past CPU time is accumulated in signal_struct
1052 * from sister threads now dead. But in this non-leader
1053 * exec, nothing survives from the original leader thread,
1054 * whose birth marks the true age of this process now.
1055 * When we take on its identity by switching to its PID, we
1056 * also take its birthdate (always earlier than our own).
1058 tsk
->start_time
= leader
->start_time
;
1059 tsk
->real_start_time
= leader
->real_start_time
;
1061 BUG_ON(!same_thread_group(leader
, tsk
));
1062 BUG_ON(has_group_leader_pid(tsk
));
1064 * An exec() starts a new thread group with the
1065 * TGID of the previous thread group. Rehash the
1066 * two threads with a switched PID, and release
1067 * the former thread group leader:
1070 /* Become a process group leader with the old leader's pid.
1071 * The old leader becomes a thread of the this thread group.
1072 * Note: The old leader also uses this pid until release_task
1073 * is called. Odd but simple and correct.
1075 tsk
->pid
= leader
->pid
;
1076 change_pid(tsk
, PIDTYPE_PID
, task_pid(leader
));
1077 transfer_pid(leader
, tsk
, PIDTYPE_PGID
);
1078 transfer_pid(leader
, tsk
, PIDTYPE_SID
);
1080 list_replace_rcu(&leader
->tasks
, &tsk
->tasks
);
1081 list_replace_init(&leader
->sibling
, &tsk
->sibling
);
1083 tsk
->group_leader
= tsk
;
1084 leader
->group_leader
= tsk
;
1086 tsk
->exit_signal
= SIGCHLD
;
1087 leader
->exit_signal
= -1;
1089 BUG_ON(leader
->exit_state
!= EXIT_ZOMBIE
);
1090 leader
->exit_state
= EXIT_DEAD
;
1093 * We are going to release_task()->ptrace_unlink() silently,
1094 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
1095 * the tracer wont't block again waiting for this thread.
1097 if (unlikely(leader
->ptrace
))
1098 __wake_up_parent(leader
, leader
->parent
);
1099 write_unlock_irq(&tasklist_lock
);
1100 threadgroup_change_end(tsk
);
1102 release_task(leader
);
1105 sig
->group_exit_task
= NULL
;
1106 sig
->notify_count
= 0;
1109 /* we have changed execution domain */
1110 tsk
->exit_signal
= SIGCHLD
;
1113 flush_itimer_signals();
1115 if (atomic_read(&oldsighand
->count
) != 1) {
1116 struct sighand_struct
*newsighand
;
1118 * This ->sighand is shared with the CLONE_SIGHAND
1119 * but not CLONE_THREAD task, switch to the new one.
1121 newsighand
= kmem_cache_alloc(sighand_cachep
, GFP_KERNEL
);
1125 atomic_set(&newsighand
->count
, 1);
1126 memcpy(newsighand
->action
, oldsighand
->action
,
1127 sizeof(newsighand
->action
));
1129 write_lock_irq(&tasklist_lock
);
1130 spin_lock(&oldsighand
->siglock
);
1131 rcu_assign_pointer(tsk
->sighand
, newsighand
);
1132 spin_unlock(&oldsighand
->siglock
);
1133 write_unlock_irq(&tasklist_lock
);
1135 __cleanup_sighand(oldsighand
);
1138 BUG_ON(!thread_group_leader(tsk
));
1142 /* protects against exit_notify() and __exit_signal() */
1143 read_lock(&tasklist_lock
);
1144 sig
->group_exit_task
= NULL
;
1145 sig
->notify_count
= 0;
1146 read_unlock(&tasklist_lock
);
1150 char *get_task_comm(char *buf
, struct task_struct
*tsk
)
1152 /* buf must be at least sizeof(tsk->comm) in size */
1154 strncpy(buf
, tsk
->comm
, sizeof(tsk
->comm
));
1158 EXPORT_SYMBOL_GPL(get_task_comm
);
1161 * These functions flushes out all traces of the currently running executable
1162 * so that a new one can be started
1165 void __set_task_comm(struct task_struct
*tsk
, const char *buf
, bool exec
)
1168 trace_task_rename(tsk
, buf
);
1169 strlcpy(tsk
->comm
, buf
, sizeof(tsk
->comm
));
1171 perf_event_comm(tsk
, exec
);
1174 int flush_old_exec(struct linux_binprm
* bprm
)
1179 * Make sure we have a private signal table and that
1180 * we are unassociated from the previous thread group.
1182 retval
= de_thread(current
);
1187 * Must be called _before_ exec_mmap() as bprm->mm is
1188 * not visibile until then. This also enables the update
1191 set_mm_exe_file(bprm
->mm
, bprm
->file
);
1194 * Release all of the old mmap stuff
1196 acct_arg_size(bprm
, 0);
1197 retval
= exec_mmap(bprm
->mm
);
1201 bprm
->mm
= NULL
; /* We're using it now */
1204 current
->flags
&= ~(PF_RANDOMIZE
| PF_FORKNOEXEC
| PF_KTHREAD
|
1205 PF_NOFREEZE
| PF_NO_SETAFFINITY
);
1207 current
->personality
&= ~bprm
->per_clear
;
1214 EXPORT_SYMBOL(flush_old_exec
);
1216 void would_dump(struct linux_binprm
*bprm
, struct file
*file
)
1218 if (inode_permission(file_inode(file
), MAY_READ
) < 0)
1219 bprm
->interp_flags
|= BINPRM_FLAGS_ENFORCE_NONDUMP
;
1221 EXPORT_SYMBOL(would_dump
);
1223 void setup_new_exec(struct linux_binprm
* bprm
)
1225 arch_pick_mmap_layout(current
->mm
);
1227 /* This is the point of no return */
1228 current
->sas_ss_sp
= current
->sas_ss_size
= 0;
1230 if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
1231 set_dumpable(current
->mm
, SUID_DUMP_USER
);
1233 set_dumpable(current
->mm
, suid_dumpable
);
1236 __set_task_comm(current
, kbasename(bprm
->filename
), true);
1238 /* Set the new mm task size. We have to do that late because it may
1239 * depend on TIF_32BIT which is only updated in flush_thread() on
1240 * some architectures like powerpc
1242 current
->mm
->task_size
= TASK_SIZE
;
1244 /* install the new credentials */
1245 if (!uid_eq(bprm
->cred
->uid
, current_euid()) ||
1246 !gid_eq(bprm
->cred
->gid
, current_egid())) {
1247 current
->pdeath_signal
= 0;
1249 would_dump(bprm
, bprm
->file
);
1250 if (bprm
->interp_flags
& BINPRM_FLAGS_ENFORCE_NONDUMP
)
1251 set_dumpable(current
->mm
, suid_dumpable
);
1254 /* An exec changes our domain. We are no longer part of the thread
1256 current
->self_exec_id
++;
1257 flush_signal_handlers(current
, 0);
1258 do_close_on_exec(current
->files
);
1260 EXPORT_SYMBOL(setup_new_exec
);
1263 * Prepare credentials and lock ->cred_guard_mutex.
1264 * install_exec_creds() commits the new creds and drops the lock.
1265 * Or, if exec fails before, free_bprm() should release ->cred and
1268 int prepare_bprm_creds(struct linux_binprm
*bprm
)
1270 if (mutex_lock_interruptible(¤t
->signal
->cred_guard_mutex
))
1271 return -ERESTARTNOINTR
;
1273 bprm
->cred
= prepare_exec_creds();
1274 if (likely(bprm
->cred
))
1277 mutex_unlock(¤t
->signal
->cred_guard_mutex
);
1281 static void free_bprm(struct linux_binprm
*bprm
)
1283 free_arg_pages(bprm
);
1285 mutex_unlock(¤t
->signal
->cred_guard_mutex
);
1286 abort_creds(bprm
->cred
);
1289 allow_write_access(bprm
->file
);
1292 /* If a binfmt changed the interp, free it. */
1293 if (bprm
->interp
!= bprm
->filename
)
1294 kfree(bprm
->interp
);
1298 int bprm_change_interp(char *interp
, struct linux_binprm
*bprm
)
1300 /* If a binfmt changed the interp, free it first. */
1301 if (bprm
->interp
!= bprm
->filename
)
1302 kfree(bprm
->interp
);
1303 bprm
->interp
= kstrdup(interp
, GFP_KERNEL
);
1308 EXPORT_SYMBOL(bprm_change_interp
);
1311 * install the new credentials for this executable
1313 void install_exec_creds(struct linux_binprm
*bprm
)
1315 security_bprm_committing_creds(bprm
);
1317 commit_creds(bprm
->cred
);
1321 * Disable monitoring for regular users
1322 * when executing setuid binaries. Must
1323 * wait until new credentials are committed
1324 * by commit_creds() above
1326 if (get_dumpable(current
->mm
) != SUID_DUMP_USER
)
1327 perf_event_exit_task(current
);
1329 * cred_guard_mutex must be held at least to this point to prevent
1330 * ptrace_attach() from altering our determination of the task's
1331 * credentials; any time after this it may be unlocked.
1333 security_bprm_committed_creds(bprm
);
1334 mutex_unlock(¤t
->signal
->cred_guard_mutex
);
1336 EXPORT_SYMBOL(install_exec_creds
);
1339 * determine how safe it is to execute the proposed program
1340 * - the caller must hold ->cred_guard_mutex to protect against
1341 * PTRACE_ATTACH or seccomp thread-sync
1343 static void check_unsafe_exec(struct linux_binprm
*bprm
)
1345 struct task_struct
*p
= current
, *t
;
1349 if (p
->ptrace
& PT_PTRACE_CAP
)
1350 bprm
->unsafe
|= LSM_UNSAFE_PTRACE_CAP
;
1352 bprm
->unsafe
|= LSM_UNSAFE_PTRACE
;
1356 * This isn't strictly necessary, but it makes it harder for LSMs to
1359 if (task_no_new_privs(current
))
1360 bprm
->unsafe
|= LSM_UNSAFE_NO_NEW_PRIVS
;
1364 spin_lock(&p
->fs
->lock
);
1366 while_each_thread(p
, t
) {
1372 if (p
->fs
->users
> n_fs
)
1373 bprm
->unsafe
|= LSM_UNSAFE_SHARE
;
1376 spin_unlock(&p
->fs
->lock
);
1379 static void bprm_fill_uid(struct linux_binprm
*bprm
)
1381 struct inode
*inode
;
1386 /* clear any previous set[ug]id data from a previous binary */
1387 bprm
->cred
->euid
= current_euid();
1388 bprm
->cred
->egid
= current_egid();
1390 if (bprm
->file
->f_path
.mnt
->mnt_flags
& MNT_NOSUID
)
1393 if (task_no_new_privs(current
))
1396 inode
= file_inode(bprm
->file
);
1397 mode
= READ_ONCE(inode
->i_mode
);
1398 if (!(mode
& (S_ISUID
|S_ISGID
)))
1401 /* Be careful if suid/sgid is set */
1404 /* reload atomically mode/uid/gid now that lock held */
1405 mode
= inode
->i_mode
;
1408 inode_unlock(inode
);
1410 /* We ignore suid/sgid if there are no mappings for them in the ns */
1411 if (!kuid_has_mapping(bprm
->cred
->user_ns
, uid
) ||
1412 !kgid_has_mapping(bprm
->cred
->user_ns
, gid
))
1415 if (mode
& S_ISUID
) {
1416 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
1417 bprm
->cred
->euid
= uid
;
1420 if ((mode
& (S_ISGID
| S_IXGRP
)) == (S_ISGID
| S_IXGRP
)) {
1421 bprm
->per_clear
|= PER_CLEAR_ON_SETID
;
1422 bprm
->cred
->egid
= gid
;
1427 * Fill the binprm structure from the inode.
1428 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
1430 * This may be called multiple times for binary chains (scripts for example).
1432 int prepare_binprm(struct linux_binprm
*bprm
)
1436 bprm_fill_uid(bprm
);
1438 /* fill in binprm security blob */
1439 retval
= security_bprm_set_creds(bprm
);
1442 bprm
->cred_prepared
= 1;
1444 memset(bprm
->buf
, 0, BINPRM_BUF_SIZE
);
1445 return kernel_read(bprm
->file
, 0, bprm
->buf
, BINPRM_BUF_SIZE
);
1448 EXPORT_SYMBOL(prepare_binprm
);
1451 * Arguments are '\0' separated strings found at the location bprm->p
1452 * points to; chop off the first by relocating brpm->p to right after
1453 * the first '\0' encountered.
1455 int remove_arg_zero(struct linux_binprm
*bprm
)
1458 unsigned long offset
;
1466 offset
= bprm
->p
& ~PAGE_MASK
;
1467 page
= get_arg_page(bprm
, bprm
->p
, 0);
1472 kaddr
= kmap_atomic(page
);
1474 for (; offset
< PAGE_SIZE
&& kaddr
[offset
];
1475 offset
++, bprm
->p
++)
1478 kunmap_atomic(kaddr
);
1481 if (offset
== PAGE_SIZE
)
1482 free_arg_page(bprm
, (bprm
->p
>> PAGE_SHIFT
) - 1);
1483 } while (offset
== PAGE_SIZE
);
1492 EXPORT_SYMBOL(remove_arg_zero
);
1494 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1496 * cycle the list of binary formats handler, until one recognizes the image
1498 int search_binary_handler(struct linux_binprm
*bprm
)
1500 bool need_retry
= IS_ENABLED(CONFIG_MODULES
);
1501 struct linux_binfmt
*fmt
;
1504 /* This allows 4 levels of binfmt rewrites before failing hard. */
1505 if (bprm
->recursion_depth
> 5)
1508 retval
= security_bprm_check(bprm
);
1514 read_lock(&binfmt_lock
);
1515 list_for_each_entry(fmt
, &formats
, lh
) {
1516 if (!try_module_get(fmt
->module
))
1518 read_unlock(&binfmt_lock
);
1519 bprm
->recursion_depth
++;
1520 retval
= fmt
->load_binary(bprm
);
1521 read_lock(&binfmt_lock
);
1523 bprm
->recursion_depth
--;
1524 if (retval
< 0 && !bprm
->mm
) {
1525 /* we got to flush_old_exec() and failed after it */
1526 read_unlock(&binfmt_lock
);
1527 force_sigsegv(SIGSEGV
, current
);
1530 if (retval
!= -ENOEXEC
|| !bprm
->file
) {
1531 read_unlock(&binfmt_lock
);
1535 read_unlock(&binfmt_lock
);
1538 if (printable(bprm
->buf
[0]) && printable(bprm
->buf
[1]) &&
1539 printable(bprm
->buf
[2]) && printable(bprm
->buf
[3]))
1541 if (request_module("binfmt-%04x", *(ushort
*)(bprm
->buf
+ 2)) < 0)
1549 EXPORT_SYMBOL(search_binary_handler
);
1551 static int exec_binprm(struct linux_binprm
*bprm
)
1553 pid_t old_pid
, old_vpid
;
1556 /* Need to fetch pid before load_binary changes it */
1557 old_pid
= current
->pid
;
1559 old_vpid
= task_pid_nr_ns(current
, task_active_pid_ns(current
->parent
));
1562 ret
= search_binary_handler(bprm
);
1565 trace_sched_process_exec(current
, old_pid
, bprm
);
1566 ptrace_event(PTRACE_EVENT_EXEC
, old_vpid
);
1567 proc_exec_connector(current
);
1574 * sys_execve() executes a new program.
1576 static int do_execveat_common(int fd
, struct filename
*filename
,
1577 struct user_arg_ptr argv
,
1578 struct user_arg_ptr envp
,
1581 char *pathbuf
= NULL
;
1582 struct linux_binprm
*bprm
;
1584 struct files_struct
*displaced
;
1587 if (IS_ERR(filename
))
1588 return PTR_ERR(filename
);
1591 * We move the actual failure in case of RLIMIT_NPROC excess from
1592 * set*uid() to execve() because too many poorly written programs
1593 * don't check setuid() return code. Here we additionally recheck
1594 * whether NPROC limit is still exceeded.
1596 if ((current
->flags
& PF_NPROC_EXCEEDED
) &&
1597 atomic_read(¤t_user()->processes
) > rlimit(RLIMIT_NPROC
)) {
1602 /* We're below the limit (still or again), so we don't want to make
1603 * further execve() calls fail. */
1604 current
->flags
&= ~PF_NPROC_EXCEEDED
;
1606 retval
= unshare_files(&displaced
);
1611 bprm
= kzalloc(sizeof(*bprm
), GFP_KERNEL
);
1615 retval
= prepare_bprm_creds(bprm
);
1619 check_unsafe_exec(bprm
);
1620 current
->in_execve
= 1;
1622 file
= do_open_execat(fd
, filename
, flags
);
1623 retval
= PTR_ERR(file
);
1630 if (fd
== AT_FDCWD
|| filename
->name
[0] == '/') {
1631 bprm
->filename
= filename
->name
;
1633 if (filename
->name
[0] == '\0')
1634 pathbuf
= kasprintf(GFP_TEMPORARY
, "/dev/fd/%d", fd
);
1636 pathbuf
= kasprintf(GFP_TEMPORARY
, "/dev/fd/%d/%s",
1637 fd
, filename
->name
);
1643 * Record that a name derived from an O_CLOEXEC fd will be
1644 * inaccessible after exec. Relies on having exclusive access to
1645 * current->files (due to unshare_files above).
1647 if (close_on_exec(fd
, rcu_dereference_raw(current
->files
->fdt
)))
1648 bprm
->interp_flags
|= BINPRM_FLAGS_PATH_INACCESSIBLE
;
1649 bprm
->filename
= pathbuf
;
1651 bprm
->interp
= bprm
->filename
;
1653 retval
= bprm_mm_init(bprm
);
1657 bprm
->argc
= count(argv
, MAX_ARG_STRINGS
);
1658 if ((retval
= bprm
->argc
) < 0)
1661 bprm
->envc
= count(envp
, MAX_ARG_STRINGS
);
1662 if ((retval
= bprm
->envc
) < 0)
1665 retval
= prepare_binprm(bprm
);
1669 retval
= copy_strings_kernel(1, &bprm
->filename
, bprm
);
1673 bprm
->exec
= bprm
->p
;
1674 retval
= copy_strings(bprm
->envc
, envp
, bprm
);
1678 retval
= copy_strings(bprm
->argc
, argv
, bprm
);
1682 retval
= exec_binprm(bprm
);
1686 /* execve succeeded */
1687 current
->fs
->in_exec
= 0;
1688 current
->in_execve
= 0;
1689 acct_update_integrals(current
);
1690 task_numa_free(current
);
1695 put_files_struct(displaced
);
1700 acct_arg_size(bprm
, 0);
1705 current
->fs
->in_exec
= 0;
1706 current
->in_execve
= 0;
1714 reset_files_struct(displaced
);
1720 int do_execve(struct filename
*filename
,
1721 const char __user
*const __user
*__argv
,
1722 const char __user
*const __user
*__envp
)
1724 struct user_arg_ptr argv
= { .ptr
.native
= __argv
};
1725 struct user_arg_ptr envp
= { .ptr
.native
= __envp
};
1726 return do_execveat_common(AT_FDCWD
, filename
, argv
, envp
, 0);
1729 int do_execveat(int fd
, struct filename
*filename
,
1730 const char __user
*const __user
*__argv
,
1731 const char __user
*const __user
*__envp
,
1734 struct user_arg_ptr argv
= { .ptr
.native
= __argv
};
1735 struct user_arg_ptr envp
= { .ptr
.native
= __envp
};
1737 return do_execveat_common(fd
, filename
, argv
, envp
, flags
);
1740 #ifdef CONFIG_COMPAT
1741 static int compat_do_execve(struct filename
*filename
,
1742 const compat_uptr_t __user
*__argv
,
1743 const compat_uptr_t __user
*__envp
)
1745 struct user_arg_ptr argv
= {
1747 .ptr
.compat
= __argv
,
1749 struct user_arg_ptr envp
= {
1751 .ptr
.compat
= __envp
,
1753 return do_execveat_common(AT_FDCWD
, filename
, argv
, envp
, 0);
1756 static int compat_do_execveat(int fd
, struct filename
*filename
,
1757 const compat_uptr_t __user
*__argv
,
1758 const compat_uptr_t __user
*__envp
,
1761 struct user_arg_ptr argv
= {
1763 .ptr
.compat
= __argv
,
1765 struct user_arg_ptr envp
= {
1767 .ptr
.compat
= __envp
,
1769 return do_execveat_common(fd
, filename
, argv
, envp
, flags
);
1773 void set_binfmt(struct linux_binfmt
*new)
1775 struct mm_struct
*mm
= current
->mm
;
1778 module_put(mm
->binfmt
->module
);
1782 __module_get(new->module
);
1784 EXPORT_SYMBOL(set_binfmt
);
1787 * set_dumpable stores three-value SUID_DUMP_* into mm->flags.
1789 void set_dumpable(struct mm_struct
*mm
, int value
)
1791 unsigned long old
, new;
1793 if (WARN_ON((unsigned)value
> SUID_DUMP_ROOT
))
1797 old
= ACCESS_ONCE(mm
->flags
);
1798 new = (old
& ~MMF_DUMPABLE_MASK
) | value
;
1799 } while (cmpxchg(&mm
->flags
, old
, new) != old
);
1802 SYSCALL_DEFINE3(execve
,
1803 const char __user
*, filename
,
1804 const char __user
*const __user
*, argv
,
1805 const char __user
*const __user
*, envp
)
1807 return do_execve(getname(filename
), argv
, envp
);
1810 SYSCALL_DEFINE5(execveat
,
1811 int, fd
, const char __user
*, filename
,
1812 const char __user
*const __user
*, argv
,
1813 const char __user
*const __user
*, envp
,
1816 int lookup_flags
= (flags
& AT_EMPTY_PATH
) ? LOOKUP_EMPTY
: 0;
1818 return do_execveat(fd
,
1819 getname_flags(filename
, lookup_flags
, NULL
),
1823 #ifdef CONFIG_COMPAT
1824 COMPAT_SYSCALL_DEFINE3(execve
, const char __user
*, filename
,
1825 const compat_uptr_t __user
*, argv
,
1826 const compat_uptr_t __user
*, envp
)
1828 return compat_do_execve(getname(filename
), argv
, envp
);
1831 COMPAT_SYSCALL_DEFINE5(execveat
, int, fd
,
1832 const char __user
*, filename
,
1833 const compat_uptr_t __user
*, argv
,
1834 const compat_uptr_t __user
*, envp
,
1837 int lookup_flags
= (flags
& AT_EMPTY_PATH
) ? LOOKUP_EMPTY
: 0;
1839 return compat_do_execveat(fd
,
1840 getname_flags(filename
, lookup_flags
, NULL
),