1	// SPDX-License-Identifier: GPL-2.0-only
2	/*
3	* linux/fs/exec.c
4	*
5	* Copyright (C) 1991, 1992 Linus Torvalds
6	*/
7
8	/*
9	* #!-checking implemented by tytso.
10	*/
11	/*
12	* Demand-loading implemented 01.12.91 - no need to read anything but
13	* the header into memory. The inode of the executable is put into
14	* "current->executable", and page faults do the actual loading. Clean.
15	*
16	* Once more I can proudly say that linux stood up to being changed: it
17	* was less than 2 hours work to get demand-loading completely implemented.
18	*
19	* Demand loading changed July 1993 by Eric Youngdale. Use mmap instead,
20	* current->executable is only used by the procfs. This allows a dispatch
21	* table to check for several different types of binary formats. We keep
22	* trying until we recognize the file or we run out of supported binary
23	* formats.
24	*/
25
26	#include <linux/kernel_read_file.h>
27	#include <linux/slab.h>
28	#include <linux/file.h>
29	#include <linux/fdtable.h>
30	#include <linux/mm.h>
31	#include <linux/stat.h>
32	#include <linux/fcntl.h>
33	#include <linux/swap.h>
34	#include <linux/string.h>
35	#include <linux/init.h>
36	#include <linux/sched/mm.h>
37	#include <linux/sched/coredump.h>
38	#include <linux/sched/signal.h>
39	#include <linux/sched/numa_balancing.h>
40	#include <linux/sched/task.h>
41	#include <linux/pagemap.h>
42	#include <linux/perf_event.h>
43	#include <linux/highmem.h>
44	#include <linux/spinlock.h>
45	#include <linux/key.h>
46	#include <linux/personality.h>
47	#include <linux/binfmts.h>
48	#include <linux/utsname.h>
49	#include <linux/pid_namespace.h>
50	#include <linux/module.h>
51	#include <linux/namei.h>
52	#include <linux/mount.h>
53	#include <linux/security.h>
54	#include <linux/syscalls.h>
55	#include <linux/tsacct_kern.h>
56	#include <linux/cn_proc.h>
57	#include <linux/audit.h>
58	#include <linux/kmod.h>
59	#include <linux/fsnotify.h>
60	#include <linux/fs_struct.h>
61	#include <linux/oom.h>
62	#include <linux/compat.h>
63	#include <linux/vmalloc.h>
64	#include <linux/io_uring.h>
65	#include <linux/syscall_user_dispatch.h>
66	#include <linux/coredump.h>
67	#include <linux/time_namespace.h>
68	#include <linux/user_events.h>
69	#include <linux/rseq.h>
70
71	#include <linux/uaccess.h>
72	#include <asm/mmu_context.h>
73	#include <asm/tlb.h>
74
75	#include <trace/events/task.h>
76	#include "internal.h"
77
78	#include <trace/events/sched.h>
79
80	static int bprm_creds_from_file(struct linux_binprm *bprm);
81
82	int suid_dumpable = 0;
83
84	static LIST_HEAD(formats);
85	static DEFINE_RWLOCK(binfmt_lock);
86
87	void __register_binfmt(struct linux_binfmt * fmt, int insert)
88	{
89	write_lock(&binfmt_lock);
90	insert ? list_add(new: &fmt->lh, head: &formats) :
91	list_add_tail(new: &fmt->lh, head: &formats);
92	write_unlock(&binfmt_lock);
93	}
94
95	EXPORT_SYMBOL(__register_binfmt);
96
97	void unregister_binfmt(struct linux_binfmt * fmt)
98	{
99	write_lock(&binfmt_lock);
100	list_del(entry: &fmt->lh);
101	write_unlock(&binfmt_lock);
102	}
103
104	EXPORT_SYMBOL(unregister_binfmt);
105
106	static inline void put_binfmt(struct linux_binfmt * fmt)
107	{
108	module_put(module: fmt->module);
109	}
110
111	bool path_noexec(const struct path *path)
112	{
113	return (path->mnt->mnt_flags & MNT_NOEXEC) ||
114	(path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
115	}
116
117	#ifdef CONFIG_USELIB
118	/*
119	* Note that a shared library must be both readable and executable due to
120	* security reasons.
121	*
122	* Also note that we take the address to load from the file itself.
123	*/
124	SYSCALL_DEFINE1(uselib, const char __user *, library)
125	{
126	struct linux_binfmt *fmt;
127	struct file *file;
128	struct filename *tmp = getname(library);
129	int error = PTR_ERR(ptr: tmp);
130	static const struct open_flags uselib_flags = {
131	.open_flag = O_LARGEFILE | O_RDONLY,
132	.acc_mode = MAY_READ | MAY_EXEC,
133	.intent = LOOKUP_OPEN,
134	.lookup_flags = LOOKUP_FOLLOW,
135	};
136
137	if (IS_ERR(ptr: tmp))
138	goto out;
139
140	file = do_filp_open(AT_FDCWD, pathname: tmp, op: &uselib_flags);
141	putname(name: tmp);
142	error = PTR_ERR(ptr: file);
143	if (IS_ERR(ptr: file))
144	goto out;
145
146	/*
147	* may_open() has already checked for this, so it should be
148	* impossible to trip now. But we need to be extra cautious
149	* and check again at the very end too.
150	*/
151	error = -EACCES;
152	if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
153	path_noexec(&file->f_path)))
154	goto exit;
155
156	error = -ENOEXEC;
157
158	read_lock(&binfmt_lock);
159	list_for_each_entry(fmt, &formats, lh) {
160	if (!fmt->load_shlib)
161	continue;
162	if (!try_module_get(module: fmt->module))
163	continue;
164	read_unlock(&binfmt_lock);
165	error = fmt->load_shlib(file);
166	read_lock(&binfmt_lock);
167	put_binfmt(fmt);
168	if (error != -ENOEXEC)
169	break;
170	}
171	read_unlock(&binfmt_lock);
172	exit:
173	fput(file);
174	out:
175	return error;
176	}
177	#endif /* #ifdef CONFIG_USELIB */
178
179	#ifdef CONFIG_MMU
180	/*
181	* The nascent bprm->mm is not visible until exec_mmap() but it can
182	* use a lot of memory, account these pages in current->mm temporary
183	* for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
184	* change the counter back via acct_arg_size(0).
185	*/
186	static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
187	{
188	struct mm_struct *mm = current->mm;
189	long diff = (long)(pages - bprm->vma_pages);
190
191	if (!mm || !diff)
192	return;
193
194	bprm->vma_pages = pages;
195	add_mm_counter(mm, member: MM_ANONPAGES, value: diff);
196	}
197
198	static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
199	int write)
200	{
201	struct page *page;
202	struct vm_area_struct *vma = bprm->vma;
203	struct mm_struct *mm = bprm->mm;
204	int ret;
205
206	/*
207	* Avoid relying on expanding the stack down in GUP (which
208	* does not work for STACK_GROWSUP anyway), and just do it
209	* by hand ahead of time.
210	*/
211	if (write && pos < vma->vm_start) {
212	mmap_write_lock(mm);
213	ret = expand_downwards(vma, address: pos);
214	if (unlikely(ret < 0)) {
215	mmap_write_unlock(mm);
216	return NULL;
217	}
218	mmap_write_downgrade(mm);
219	} else
220	mmap_read_lock(mm);
221
222	/*
223	* We are doing an exec(). 'current' is the process
224	* doing the exec and 'mm' is the new process's mm.
225	*/
226	ret = get_user_pages_remote(mm, start: pos, nr_pages: 1,
227	gup_flags: write ? FOLL_WRITE : 0,
228	pages: &page, NULL);
229	mmap_read_unlock(mm);
230	if (ret <= 0)
231	return NULL;
232
233	if (write)
234	acct_arg_size(bprm, pages: vma_pages(vma));
235
236	return page;
237	}
238
239	static void put_arg_page(struct page *page)
240	{
241	put_page(page);
242	}
243
244	static void free_arg_pages(struct linux_binprm *bprm)
245	{
246	}
247
248	static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
249	struct page *page)
250	{
251	flush_cache_page(vma: bprm->vma, vmaddr: pos, page_to_pfn(page));
252	}
253
254	static int __bprm_mm_init(struct linux_binprm *bprm)
255	{
256	int err;
257	struct vm_area_struct *vma = NULL;
258	struct mm_struct *mm = bprm->mm;
259
260	bprm->vma = vma = vm_area_alloc(mm);
261	if (!vma)
262	return -ENOMEM;
263	vma_set_anonymous(vma);
264
265	if (mmap_write_lock_killable(mm)) {
266	err = -EINTR;
267	goto err_free;
268	}
269
270	/*
271	* Place the stack at the largest stack address the architecture
272	* supports. Later, we'll move this to an appropriate place. We don't
273	* use STACK_TOP because that can depend on attributes which aren't
274	* configured yet.
275	*/
276	BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
277	vma->vm_end = STACK_TOP_MAX;
278	vma->vm_start = vma->vm_end - PAGE_SIZE;
279	vm_flags_init(vma, VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP);
280	vma->vm_page_prot = vm_get_page_prot(vm_flags: vma->vm_flags);
281
282	err = insert_vm_struct(mm, vma);
283	if (err)
284	goto err;
285
286	mm->stack_vm = mm->total_vm = 1;
287	mmap_write_unlock(mm);
288	bprm->p = vma->vm_end - sizeof(void *);
289	return 0;
290	err:
291	mmap_write_unlock(mm);
292	err_free:
293	bprm->vma = NULL;
294	vm_area_free(vma);
295	return err;
296	}
297
298	static bool valid_arg_len(struct linux_binprm *bprm, long len)
299	{
300	return len <= MAX_ARG_STRLEN;
301	}
302
303	#else
304
305	static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
306	{
307	}
308
309	static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
310	int write)
311	{
312	struct page *page;
313
314	page = bprm->page[pos / PAGE_SIZE];
315	if (!page && write) {
316	page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
317	if (!page)
318	return NULL;
319	bprm->page[pos / PAGE_SIZE] = page;
320	}
321
322	return page;
323	}
324
325	static void put_arg_page(struct page *page)
326	{
327	}
328
329	static void free_arg_page(struct linux_binprm *bprm, int i)
330	{
331	if (bprm->page[i]) {
332	__free_page(bprm->page[i]);
333	bprm->page[i] = NULL;
334	}
335	}
336
337	static void free_arg_pages(struct linux_binprm *bprm)
338	{
339	int i;
340
341	for (i = 0; i < MAX_ARG_PAGES; i++)
342	free_arg_page(bprm, i);
343	}
344
345	static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
346	struct page *page)
347	{
348	}
349
350	static int __bprm_mm_init(struct linux_binprm *bprm)
351	{
352	bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
353	return 0;
354	}
355
356	static bool valid_arg_len(struct linux_binprm *bprm, long len)
357	{
358	return len <= bprm->p;
359	}
360
361	#endif /* CONFIG_MMU */
362
363	/*
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().
368	*/
369	static int bprm_mm_init(struct linux_binprm *bprm)
370	{
371	int err;
372	struct mm_struct *mm = NULL;
373
374	bprm->mm = mm = mm_alloc();
375	err = -ENOMEM;
376	if (!mm)
377	goto err;
378
379	/* Save current stack limit for all calculations made during exec. */
380	task_lock(current->group_leader);
381	bprm->rlim_stack = current->signal->rlim[RLIMIT_STACK];
382	task_unlock(current->group_leader);
383
384	err = __bprm_mm_init(bprm);
385	if (err)
386	goto err;
387
388	return 0;
389
390	err:
391	if (mm) {
392	bprm->mm = NULL;
393	mmdrop(mm);
394	}
395
396	return err;
397	}
398
399	struct user_arg_ptr {
400	#ifdef CONFIG_COMPAT
401	bool is_compat;
402	#endif
403	union {
404	const char __user *const __user *native;
405	#ifdef CONFIG_COMPAT
406	const compat_uptr_t __user *compat;
407	#endif
408	} ptr;
409	};
410
411	static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
412	{
413	const char __user *native;
414
415	#ifdef CONFIG_COMPAT
416	if (unlikely(argv.is_compat)) {
417	compat_uptr_t compat;
418
419	if (get_user(compat, argv.ptr.compat + nr))
420	return ERR_PTR(error: -EFAULT);
421
422	return compat_ptr(uptr: compat);
423	}
424	#endif
425
426	if (get_user(native, argv.ptr.native + nr))
427	return ERR_PTR(error: -EFAULT);
428
429	return native;
430	}
431
432	/*
433	* count() counts the number of strings in array ARGV.
434	*/
435	static int count(struct user_arg_ptr argv, int max)
436	{
437	int i = 0;
438
439	if (argv.ptr.native != NULL) {
440	for (;;) {
441	const char __user *p = get_user_arg_ptr(argv, nr: i);
442
443	if (!p)
444	break;
445
446	if (IS_ERR(ptr: p))
447	return -EFAULT;
448
449	if (i >= max)
450	return -E2BIG;
451	++i;
452
453	if (fatal_signal_pending(current))
454	return -ERESTARTNOHAND;
455	cond_resched();
456	}
457	}
458	return i;
459	}
460
461	static int count_strings_kernel(const char *const *argv)
462	{
463	int i;
464
465	if (!argv)
466	return 0;
467
468	for (i = 0; argv[i]; ++i) {
469	if (i >= MAX_ARG_STRINGS)
470	return -E2BIG;
471	if (fatal_signal_pending(current))
472	return -ERESTARTNOHAND;
473	cond_resched();
474	}
475	return i;
476	}
477
478	static int bprm_stack_limits(struct linux_binprm *bprm)
479	{
480	unsigned long limit, ptr_size;
481
482	/*
483	* Limit to 1/4 of the max stack size or 3/4 of _STK_LIM
484	* (whichever is smaller) for the argv+env strings.
485	* This ensures that:
486	* - the remaining binfmt code will not run out of stack space,
487	* - the program will have a reasonable amount of stack left
488	* to work from.
489	*/
490	limit = _STK_LIM / 4 * 3;
491	limit = min(limit, bprm->rlim_stack.rlim_cur / 4);
492	/*
493	* We've historically supported up to 32 pages (ARG_MAX)
494	* of argument strings even with small stacks
495	*/
496	limit = max_t(unsigned long, limit, ARG_MAX);
497	/*
498	* We must account for the size of all the argv and envp pointers to
499	* the argv and envp strings, since they will also take up space in
500	* the stack. They aren't stored until much later when we can't
501	* signal to the parent that the child has run out of stack space.
502	* Instead, calculate it here so it's possible to fail gracefully.
503	*
504	* In the case of argc = 0, make sure there is space for adding a
505	* empty string (which will bump argc to 1), to ensure confused
506	* userspace programs don't start processing from argv[1], thinking
507	* argc can never be 0, to keep them from walking envp by accident.
508	* See do_execveat_common().
509	*/
510	ptr_size = (max(bprm->argc, 1) + bprm->envc) * sizeof(void *);
511	if (limit <= ptr_size)
512	return -E2BIG;
513	limit -= ptr_size;
514
515	bprm->argmin = bprm->p - limit;
516	return 0;
517	}
518
519	/*
520	* 'copy_strings()' copies argument/environment strings from the old
521	* processes's memory to the new process's stack. The call to get_user_pages()
522	* ensures the destination page is created and not swapped out.
523	*/
524	static int copy_strings(int argc, struct user_arg_ptr argv,
525	struct linux_binprm *bprm)
526	{
527	struct page *kmapped_page = NULL;
528	char *kaddr = NULL;
529	unsigned long kpos = 0;
530	int ret;
531
532	while (argc-- > 0) {
533	const char __user *str;
534	int len;
535	unsigned long pos;
536
537	ret = -EFAULT;
538	str = get_user_arg_ptr(argv, nr: argc);
539	if (IS_ERR(ptr: str))
540	goto out;
541
542	len = strnlen_user(str, MAX_ARG_STRLEN);
543	if (!len)
544	goto out;
545
546	ret = -E2BIG;
547	if (!valid_arg_len(bprm, len))
548	goto out;
549
550	/* We're going to work our way backwards. */
551	pos = bprm->p;
552	str += len;
553	bprm->p -= len;
554	#ifdef CONFIG_MMU
555	if (bprm->p < bprm->argmin)
556	goto out;
557	#endif
558
559	while (len > 0) {
560	int offset, bytes_to_copy;
561
562	if (fatal_signal_pending(current)) {
563	ret = -ERESTARTNOHAND;
564	goto out;
565	}
566	cond_resched();
567
568	offset = pos % PAGE_SIZE;
569	if (offset == 0)
570	offset = PAGE_SIZE;
571
572	bytes_to_copy = offset;
573	if (bytes_to_copy > len)
574	bytes_to_copy = len;
575
576	offset -= bytes_to_copy;
577	pos -= bytes_to_copy;
578	str -= bytes_to_copy;
579	len -= bytes_to_copy;
580
581	if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
582	struct page *page;
583
584	page = get_arg_page(bprm, pos, write: 1);
585	if (!page) {
586	ret = -E2BIG;
587	goto out;
588	}
589
590	if (kmapped_page) {
591	flush_dcache_page(page: kmapped_page);
592	kunmap_local(kaddr);
593	put_arg_page(page: kmapped_page);
594	}
595	kmapped_page = page;
596	kaddr = kmap_local_page(page: kmapped_page);
597	kpos = pos & PAGE_MASK;
598	flush_arg_page(bprm, pos: kpos, page: kmapped_page);
599	}
600	if (copy_from_user(to: kaddr+offset, from: str, n: bytes_to_copy)) {
601	ret = -EFAULT;
602	goto out;
603	}
604	}
605	}
606	ret = 0;
607	out:
608	if (kmapped_page) {
609	flush_dcache_page(page: kmapped_page);
610	kunmap_local(kaddr);
611	put_arg_page(page: kmapped_page);
612	}
613	return ret;
614	}
615
616	/*
617	* Copy and argument/environment string from the kernel to the processes stack.
618	*/
619	int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
620	{
621	int len = strnlen(p: arg, MAX_ARG_STRLEN) + 1 /* terminating NUL */;
622	unsigned long pos = bprm->p;
623
624	if (len == 0)
625	return -EFAULT;
626	if (!valid_arg_len(bprm, len))
627	return -E2BIG;
628
629	/* We're going to work our way backwards. */
630	arg += len;
631	bprm->p -= len;
632	if (IS_ENABLED(CONFIG_MMU) && bprm->p < bprm->argmin)
633	return -E2BIG;
634
635	while (len > 0) {
636	unsigned int bytes_to_copy = min_t(unsigned int, len,
637	min_not_zero(offset_in_page(pos), PAGE_SIZE));
638	struct page *page;
639
640	pos -= bytes_to_copy;
641	arg -= bytes_to_copy;
642	len -= bytes_to_copy;
643
644	page = get_arg_page(bprm, pos, write: 1);
645	if (!page)
646	return -E2BIG;
647	flush_arg_page(bprm, pos: pos & PAGE_MASK, page);
648	memcpy_to_page(page, offset_in_page(pos), from: arg, len: bytes_to_copy);
649	put_arg_page(page);
650	}
651
652	return 0;
653	}
654	EXPORT_SYMBOL(copy_string_kernel);
655
656	static int copy_strings_kernel(int argc, const char *const *argv,
657	struct linux_binprm *bprm)
658	{
659	while (argc-- > 0) {
660	int ret = copy_string_kernel(argv[argc], bprm);
661	if (ret < 0)
662	return ret;
663	if (fatal_signal_pending(current))
664	return -ERESTARTNOHAND;
665	cond_resched();
666	}
667	return 0;
668	}
669
670	#ifdef CONFIG_MMU
671
672	/*
673	* During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
674	* the binfmt code determines where the new stack should reside, we shift it to
675	* its final location. The process proceeds as follows:
676	*
677	* 1) Use shift to calculate the new vma endpoints.
678	* 2) Extend vma to cover both the old and new ranges. This ensures the
679	* arguments passed to subsequent functions are consistent.
680	* 3) Move vma's page tables to the new range.
681	* 4) Free up any cleared pgd range.
682	* 5) Shrink the vma to cover only the new range.
683	*/
684	static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
685	{
686	struct mm_struct *mm = vma->vm_mm;
687	unsigned long old_start = vma->vm_start;
688	unsigned long old_end = vma->vm_end;
689	unsigned long length = old_end - old_start;
690	unsigned long new_start = old_start - shift;
691	unsigned long new_end = old_end - shift;
692	VMA_ITERATOR(vmi, mm, new_start);
693	struct vm_area_struct *next;
694	struct mmu_gather tlb;
695
696	BUG_ON(new_start > new_end);
697
698	/*
699	* ensure there are no vmas between where we want to go
700	* and where we are
701	*/
702	if (vma != vma_next(vmi: &vmi))
703	return -EFAULT;
704
705	vma_iter_prev_range(vmi: &vmi);
706	/*
707	* cover the whole range: [new_start, old_end)
708	*/
709	if (vma_expand(vmi: &vmi, vma, start: new_start, end: old_end, pgoff: vma->vm_pgoff, NULL))
710	return -ENOMEM;
711
712	/*
713	* move the page tables downwards, on failure we rely on
714	* process cleanup to remove whatever mess we made.
715	*/
716	if (length != move_page_tables(vma, old_addr: old_start,
717	new_vma: vma, new_addr: new_start, len: length, need_rmap_locks: false, for_stack: true))
718	return -ENOMEM;
719
720	lru_add_drain();
721	tlb_gather_mmu(tlb: &tlb, mm);
722	next = vma_next(vmi: &vmi);
723	if (new_end > old_start) {
724	/*
725	* when the old and new regions overlap clear from new_end.
726	*/
727	free_pgd_range(tlb: &tlb, addr: new_end, end: old_end, floor: new_end,
728	ceiling: next ? next->vm_start : USER_PGTABLES_CEILING);
729	} else {
730	/*
731	* otherwise, clean from old_start; this is done to not touch
732	* the address space in [new_end, old_start) some architectures
733	* have constraints on va-space that make this illegal (IA64) -
734	* for the others its just a little faster.
735	*/
736	free_pgd_range(tlb: &tlb, addr: old_start, end: old_end, floor: new_end,
737	ceiling: next ? next->vm_start : USER_PGTABLES_CEILING);
738	}
739	tlb_finish_mmu(tlb: &tlb);
740
741	vma_prev(vmi: &vmi);
742	/* Shrink the vma to just the new range */
743	return vma_shrink(vmi: &vmi, vma, start: new_start, end: new_end, pgoff: vma->vm_pgoff);
744	}
745
746	/*
747	* Finalizes the stack vm_area_struct. The flags and permissions are updated,
748	* the stack is optionally relocated, and some extra space is added.
749	*/
750	int setup_arg_pages(struct linux_binprm *bprm,
751	unsigned long stack_top,
752	int executable_stack)
753	{
754	unsigned long ret;
755	unsigned long stack_shift;
756	struct mm_struct *mm = current->mm;
757	struct vm_area_struct *vma = bprm->vma;
758	struct vm_area_struct *prev = NULL;
759	unsigned long vm_flags;
760	unsigned long stack_base;
761	unsigned long stack_size;
762	unsigned long stack_expand;
763	unsigned long rlim_stack;
764	struct mmu_gather tlb;
765	struct vma_iterator vmi;
766
767	#ifdef CONFIG_STACK_GROWSUP
768	/* Limit stack size */
769	stack_base = bprm->rlim_stack.rlim_max;
770
771	stack_base = calc_max_stack_size(stack_base);
772
773	/* Add space for stack randomization. */
774	stack_base += (STACK_RND_MASK << PAGE_SHIFT);
775
776	/* Make sure we didn't let the argument array grow too large. */
777	if (vma->vm_end - vma->vm_start > stack_base)
778	return -ENOMEM;
779
780	stack_base = PAGE_ALIGN(stack_top - stack_base);
781
782	stack_shift = vma->vm_start - stack_base;
783	mm->arg_start = bprm->p - stack_shift;
784	bprm->p = vma->vm_end - stack_shift;
785	#else
786	stack_top = arch_align_stack(sp: stack_top);
787	stack_top = PAGE_ALIGN(stack_top);
788
789	if (unlikely(stack_top < mmap_min_addr) ||
790	unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
791	return -ENOMEM;
792
793	stack_shift = vma->vm_end - stack_top;
794
795	bprm->p -= stack_shift;
796	mm->arg_start = bprm->p;
797	#endif
798
799	if (bprm->loader)
800	bprm->loader -= stack_shift;
801	bprm->exec -= stack_shift;
802
803	if (mmap_write_lock_killable(mm))
804	return -EINTR;
805
806	vm_flags = VM_STACK_FLAGS;
807
808	/*
809	* Adjust stack execute permissions; explicitly enable for
810	* EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
811	* (arch default) otherwise.
812	*/
813	if (unlikely(executable_stack == EXSTACK_ENABLE_X))
814	vm_flags |= VM_EXEC;
815	else if (executable_stack == EXSTACK_DISABLE_X)
816	vm_flags &= ~VM_EXEC;
817	vm_flags |= mm->def_flags;
818	vm_flags |= VM_STACK_INCOMPLETE_SETUP;
819
820	vma_iter_init(vmi: &vmi, mm, addr: vma->vm_start);
821
822	tlb_gather_mmu(tlb: &tlb, mm);
823	ret = mprotect_fixup(vmi: &vmi, tlb: &tlb, vma, pprev: &prev, start: vma->vm_start, end: vma->vm_end,
824	newflags: vm_flags);
825	tlb_finish_mmu(tlb: &tlb);
826
827	if (ret)
828	goto out_unlock;
829	BUG_ON(prev != vma);
830
831	if (unlikely(vm_flags & VM_EXEC)) {
832	pr_warn_once("process '%pD4' started with executable stack\n",
833	bprm->file);
834	}
835
836	/* Move stack pages down in memory. */
837	if (stack_shift) {
838	ret = shift_arg_pages(vma, shift: stack_shift);
839	if (ret)
840	goto out_unlock;
841	}
842
843	/* mprotect_fixup is overkill to remove the temporary stack flags */
844	vm_flags_clear(vma, VM_STACK_INCOMPLETE_SETUP);
845
846	stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
847	stack_size = vma->vm_end - vma->vm_start;
848	/*
849	* Align this down to a page boundary as expand_stack
850	* will align it up.
851	*/
852	rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK;
853
854	stack_expand = min(rlim_stack, stack_size + stack_expand);
855
856	#ifdef CONFIG_STACK_GROWSUP
857	stack_base = vma->vm_start + stack_expand;
858	#else
859	stack_base = vma->vm_end - stack_expand;
860	#endif
861	current->mm->start_stack = bprm->p;
862	ret = expand_stack_locked(vma, address: stack_base);
863	if (ret)
864	ret = -EFAULT;
865
866	out_unlock:
867	mmap_write_unlock(mm);
868	return ret;
869	}
870	EXPORT_SYMBOL(setup_arg_pages);
871
872	#else
873
874	/*
875	* Transfer the program arguments and environment from the holding pages
876	* onto the stack. The provided stack pointer is adjusted accordingly.
877	*/
878	int transfer_args_to_stack(struct linux_binprm *bprm,
879	unsigned long *sp_location)
880	{
881	unsigned long index, stop, sp;
882	int ret = 0;
883
884	stop = bprm->p >> PAGE_SHIFT;
885	sp = *sp_location;
886
887	for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
888	unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0;
889	char *src = kmap_local_page(bprm->page[index]) + offset;
890	sp -= PAGE_SIZE - offset;
891	if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0)
892	ret = -EFAULT;
893	kunmap_local(src);
894	if (ret)
895	goto out;
896	}
897
898	bprm->exec += *sp_location - MAX_ARG_PAGES * PAGE_SIZE;
899	*sp_location = sp;
900
901	out:
902	return ret;
903	}
904	EXPORT_SYMBOL(transfer_args_to_stack);
905
906	#endif /* CONFIG_MMU */
907
908	/*
909	* On success, caller must call do_close_execat() on the returned
910	* struct file to close it.
911	*/
912	static struct file *do_open_execat(int fd, struct filename *name, int flags)
913	{
914	struct file *file;
915	int err;
916	struct open_flags open_exec_flags = {
917	.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
918	.acc_mode = MAY_EXEC,
919	.intent = LOOKUP_OPEN,
920	.lookup_flags = LOOKUP_FOLLOW,
921	};
922
923	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
924	return ERR_PTR(error: -EINVAL);
925	if (flags & AT_SYMLINK_NOFOLLOW)
926	open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
927	if (flags & AT_EMPTY_PATH)
928	open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
929
930	file = do_filp_open(dfd: fd, pathname: name, op: &open_exec_flags);
931	if (IS_ERR(ptr: file))
932	goto out;
933
934	/*
935	* may_open() has already checked for this, so it should be
936	* impossible to trip now. But we need to be extra cautious
937	* and check again at the very end too.
938	*/
939	err = -EACCES;
940	if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
941	path_noexec(&file->f_path)))
942	goto exit;
943
944	err = deny_write_access(file);
945	if (err)
946	goto exit;
947
948	out:
949	return file;
950
951	exit:
952	fput(file);
953	return ERR_PTR(error: err);
954	}
955
956	/**
957	* open_exec - Open a path name for execution
958	*
959	* @name: path name to open with the intent of executing it.
960	*
961	* Returns ERR_PTR on failure or allocated struct file on success.
962	*
963	* As this is a wrapper for the internal do_open_execat(), callers
964	* must call allow_write_access() before fput() on release. Also see
965	* do_close_execat().
966	*/
967	struct file *open_exec(const char *name)
968	{
969	struct filename *filename = getname_kernel(name);
970	struct file *f = ERR_CAST(ptr: filename);
971
972	if (!IS_ERR(ptr: filename)) {
973	f = do_open_execat(AT_FDCWD, name: filename, flags: 0);
974	putname(name: filename);
975	}
976	return f;
977	}
978	EXPORT_SYMBOL(open_exec);
979
980	#if defined(CONFIG_BINFMT_FLAT) || defined(CONFIG_BINFMT_ELF_FDPIC)
981	ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
982	{
983	ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
984	if (res > 0)
985	flush_icache_user_range(addr, addr + len);
986	return res;
987	}
988	EXPORT_SYMBOL(read_code);
989	#endif
990
991	/*
992	* Maps the mm_struct mm into the current task struct.
993	* On success, this function returns with exec_update_lock
994	* held for writing.
995	*/
996	static int exec_mmap(struct mm_struct *mm)
997	{
998	struct task_struct *tsk;
999	struct mm_struct *old_mm, *active_mm;
1000	int ret;
1001
1002	/* Notify parent that we're no longer interested in the old VM */
1003	tsk = current;
1004	old_mm = current->mm;
1005	exec_mm_release(tsk, old_mm);
1006
1007	ret = down_write_killable(sem: &tsk->signal->exec_update_lock);
1008	if (ret)
1009	return ret;
1010
1011	if (old_mm) {
1012	/*
1013	* If there is a pending fatal signal perhaps a signal
1014	* whose default action is to create a coredump get
1015	* out and die instead of going through with the exec.
1016	*/
1017	ret = mmap_read_lock_killable(mm: old_mm);
1018	if (ret) {
1019	up_write(sem: &tsk->signal->exec_update_lock);
1020	return ret;
1021	}
1022	}
1023
1024	task_lock(p: tsk);
1025	membarrier_exec_mmap(mm);
1026
1027	local_irq_disable();
1028	active_mm = tsk->active_mm;
1029	tsk->active_mm = mm;
1030	tsk->mm = mm;
1031	mm_init_cid(mm);
1032	/*
1033	* This prevents preemption while active_mm is being loaded and
1034	* it and mm are being updated, which could cause problems for
1035	* lazy tlb mm refcounting when these are updated by context
1036	* switches. Not all architectures can handle irqs off over
1037	* activate_mm yet.
1038	*/
1039	if (!IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
1040	local_irq_enable();
1041	activate_mm(active_mm, mm);
1042	if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
1043	local_irq_enable();
1044	lru_gen_add_mm(mm);
1045	task_unlock(p: tsk);
1046	lru_gen_use_mm(mm);
1047	if (old_mm) {
1048	mmap_read_unlock(mm: old_mm);
1049	BUG_ON(active_mm != old_mm);
1050	setmax_mm_hiwater_rss(maxrss: &tsk->signal->maxrss, mm: old_mm);
1051	mm_update_next_owner(mm: old_mm);
1052	mmput(old_mm);
1053	return 0;
1054	}
1055	mmdrop_lazy_tlb(mm: active_mm);
1056	return 0;
1057	}
1058
1059	static int de_thread(struct task_struct *tsk)
1060	{
1061	struct signal_struct *sig = tsk->signal;
1062	struct sighand_struct *oldsighand = tsk->sighand;
1063	spinlock_t *lock = &oldsighand->siglock;
1064
1065	if (thread_group_empty(p: tsk))
1066	goto no_thread_group;
1067
1068	/*
1069	* Kill all other threads in the thread group.
1070	*/
1071	spin_lock_irq(lock);
1072	if ((sig->flags & SIGNAL_GROUP_EXIT) || sig->group_exec_task) {
1073	/*
1074	* Another group action in progress, just
1075	* return so that the signal is processed.
1076	*/
1077	spin_unlock_irq(lock);
1078	return -EAGAIN;
1079	}
1080
1081	sig->group_exec_task = tsk;
1082	sig->notify_count = zap_other_threads(p: tsk);
1083	if (!thread_group_leader(p: tsk))
1084	sig->notify_count--;
1085
1086	while (sig->notify_count) {
1087	__set_current_state(TASK_KILLABLE);
1088	spin_unlock_irq(lock);
1089	schedule();
1090	if (__fatal_signal_pending(p: tsk))
1091	goto killed;
1092	spin_lock_irq(lock);
1093	}
1094	spin_unlock_irq(lock);
1095
1096	/*
1097	* At this point all other threads have exited, all we have to
1098	* do is to wait for the thread group leader to become inactive,
1099	* and to assume its PID:
1100	*/
1101	if (!thread_group_leader(p: tsk)) {
1102	struct task_struct *leader = tsk->group_leader;
1103
1104	for (;;) {
1105	cgroup_threadgroup_change_begin(tsk);
1106	write_lock_irq(&tasklist_lock);
1107	/*
1108	* Do this under tasklist_lock to ensure that
1109	* exit_notify() can't miss ->group_exec_task
1110	*/
1111	sig->notify_count = -1;
1112	if (likely(leader->exit_state))
1113	break;
1114	__set_current_state(TASK_KILLABLE);
1115	write_unlock_irq(&tasklist_lock);
1116	cgroup_threadgroup_change_end(tsk);
1117	schedule();
1118	if (__fatal_signal_pending(p: tsk))
1119	goto killed;
1120	}
1121
1122	/*
1123	* The only record we have of the real-time age of a
1124	* process, regardless of execs it's done, is start_time.
1125	* All the past CPU time is accumulated in signal_struct
1126	* from sister threads now dead. But in this non-leader
1127	* exec, nothing survives from the original leader thread,
1128	* whose birth marks the true age of this process now.
1129	* When we take on its identity by switching to its PID, we
1130	* also take its birthdate (always earlier than our own).
1131	*/
1132	tsk->start_time = leader->start_time;
1133	tsk->start_boottime = leader->start_boottime;
1134
1135	BUG_ON(!same_thread_group(leader, tsk));
1136	/*
1137	* An exec() starts a new thread group with the
1138	* TGID of the previous thread group. Rehash the
1139	* two threads with a switched PID, and release
1140	* the former thread group leader:
1141	*/
1142
1143	/* Become a process group leader with the old leader's pid.
1144	* The old leader becomes a thread of the this thread group.
1145	*/
1146	exchange_tids(task: tsk, old: leader);
1147	transfer_pid(old: leader, new: tsk, PIDTYPE_TGID);
1148	transfer_pid(old: leader, new: tsk, PIDTYPE_PGID);
1149	transfer_pid(old: leader, new: tsk, PIDTYPE_SID);
1150
1151	list_replace_rcu(old: &leader->tasks, new: &tsk->tasks);
1152	list_replace_init(old: &leader->sibling, new: &tsk->sibling);
1153
1154	tsk->group_leader = tsk;
1155	leader->group_leader = tsk;
1156
1157	tsk->exit_signal = SIGCHLD;
1158	leader->exit_signal = -1;
1159
1160	BUG_ON(leader->exit_state != EXIT_ZOMBIE);
1161	leader->exit_state = EXIT_DEAD;
1162	/*
1163	* We are going to release_task()->ptrace_unlink() silently,
1164	* the tracer can sleep in do_wait(). EXIT_DEAD guarantees
1165	* the tracer won't block again waiting for this thread.
1166	*/
1167	if (unlikely(leader->ptrace))
1168	__wake_up_parent(p: leader, parent: leader->parent);
1169	write_unlock_irq(&tasklist_lock);
1170	cgroup_threadgroup_change_end(tsk);
1171
1172	release_task(p: leader);
1173	}
1174
1175	sig->group_exec_task = NULL;
1176	sig->notify_count = 0;
1177
1178	no_thread_group:
1179	/* we have changed execution domain */
1180	tsk->exit_signal = SIGCHLD;
1181
1182	BUG_ON(!thread_group_leader(tsk));
1183	return 0;
1184
1185	killed:
1186	/* protects against exit_notify() and __exit_signal() */
1187	read_lock(&tasklist_lock);
1188	sig->group_exec_task = NULL;
1189	sig->notify_count = 0;
1190	read_unlock(&tasklist_lock);
1191	return -EAGAIN;
1192	}
1193
1194
1195	/*
1196	* This function makes sure the current process has its own signal table,
1197	* so that flush_signal_handlers can later reset the handlers without
1198	* disturbing other processes. (Other processes might share the signal
1199	* table via the CLONE_SIGHAND option to clone().)
1200	*/
1201	static int unshare_sighand(struct task_struct *me)
1202	{
1203	struct sighand_struct *oldsighand = me->sighand;
1204
1205	if (refcount_read(r: &oldsighand->count) != 1) {
1206	struct sighand_struct *newsighand;
1207	/*
1208	* This ->sighand is shared with the CLONE_SIGHAND
1209	* but not CLONE_THREAD task, switch to the new one.
1210	*/
1211	newsighand = kmem_cache_alloc(cachep: sighand_cachep, GFP_KERNEL);
1212	if (!newsighand)
1213	return -ENOMEM;
1214
1215	refcount_set(r: &newsighand->count, n: 1);
1216
1217	write_lock_irq(&tasklist_lock);
1218	spin_lock(lock: &oldsighand->siglock);
1219	memcpy(newsighand->action, oldsighand->action,
1220	sizeof(newsighand->action));
1221	rcu_assign_pointer(me->sighand, newsighand);
1222	spin_unlock(lock: &oldsighand->siglock);
1223	write_unlock_irq(&tasklist_lock);
1224
1225	__cleanup_sighand(oldsighand);
1226	}
1227	return 0;
1228	}
1229
1230	char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk)
1231	{
1232	task_lock(p: tsk);
1233	/* Always NUL terminated and zero-padded */
1234	strscpy_pad(buf, tsk->comm, buf_size);
1235	task_unlock(p: tsk);
1236	return buf;
1237	}
1238	EXPORT_SYMBOL_GPL(__get_task_comm);
1239
1240	/*
1241	* These functions flushes out all traces of the currently running executable
1242	* so that a new one can be started
1243	*/
1244
1245	void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
1246	{
1247	task_lock(p: tsk);
1248	trace_task_rename(task: tsk, comm: buf);
1249	strscpy_pad(tsk->comm, buf, sizeof(tsk->comm));
1250	task_unlock(p: tsk);
1251	perf_event_comm(tsk, exec);
1252	}
1253
1254	/*
1255	* Calling this is the point of no return. None of the failures will be
1256	* seen by userspace since either the process is already taking a fatal
1257	* signal (via de_thread() or coredump), or will have SEGV raised
1258	* (after exec_mmap()) by search_binary_handler (see below).
1259	*/
1260	int begin_new_exec(struct linux_binprm * bprm)
1261	{
1262	struct task_struct *me = current;
1263	int retval;
1264
1265	/* Once we are committed compute the creds */
1266	retval = bprm_creds_from_file(bprm);
1267	if (retval)
1268	return retval;
1269
1270	/*
1271	* Ensure all future errors are fatal.
1272	*/
1273	bprm->point_of_no_return = true;
1274
1275	/*
1276	* Make this the only thread in the thread group.
1277	*/
1278	retval = de_thread(tsk: me);
1279	if (retval)
1280	goto out;
1281
1282	/*
1283	* Cancel any io_uring activity across execve
1284	*/
1285	io_uring_task_cancel();
1286
1287	/* Ensure the files table is not shared. */
1288	retval = unshare_files();
1289	if (retval)
1290	goto out;
1291
1292	/*
1293	* Must be called _before_ exec_mmap() as bprm->mm is
1294	* not visible until then. Doing it here also ensures
1295	* we don't race against replace_mm_exe_file().
1296	*/
1297	retval = set_mm_exe_file(mm: bprm->mm, new_exe_file: bprm->file);
1298	if (retval)
1299	goto out;
1300
1301	/* If the binary is not readable then enforce mm->dumpable=0 */
1302	would_dump(bprm, bprm->file);
1303	if (bprm->have_execfd)
1304	would_dump(bprm, bprm->executable);
1305
1306	/*
1307	* Release all of the old mmap stuff
1308	*/
1309	acct_arg_size(bprm, pages: 0);
1310	retval = exec_mmap(mm: bprm->mm);
1311	if (retval)
1312	goto out;
1313
1314	bprm->mm = NULL;
1315
1316	retval = exec_task_namespaces();
1317	if (retval)
1318	goto out_unlock;
1319
1320	#ifdef CONFIG_POSIX_TIMERS
1321	spin_lock_irq(lock: &me->sighand->siglock);
1322	posix_cpu_timers_exit(task: me);
1323	spin_unlock_irq(lock: &me->sighand->siglock);
1324	exit_itimers(me);
1325	flush_itimer_signals();
1326	#endif
1327
1328	/*
1329	* Make the signal table private.
1330	*/
1331	retval = unshare_sighand(me);
1332	if (retval)
1333	goto out_unlock;
1334
1335	me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC |
1336	PF_NOFREEZE | PF_NO_SETAFFINITY);
1337	flush_thread();
1338	me->personality &= ~bprm->per_clear;
1339
1340	clear_syscall_work_syscall_user_dispatch(me);
1341
1342	/*
1343	* We have to apply CLOEXEC before we change whether the process is
1344	* dumpable (in setup_new_exec) to avoid a race with a process in userspace
1345	* trying to access the should-be-closed file descriptors of a process
1346	* undergoing exec(2).
1347	*/
1348	do_close_on_exec(me->files);
1349
1350	if (bprm->secureexec) {
1351	/* Make sure parent cannot signal privileged process. */
1352	me->pdeath_signal = 0;
1353
1354	/*
1355	* For secureexec, reset the stack limit to sane default to
1356	* avoid bad behavior from the prior rlimits. This has to
1357	* happen before arch_pick_mmap_layout(), which examines
1358	* RLIMIT_STACK, but after the point of no return to avoid
1359	* needing to clean up the change on failure.
1360	*/
1361	if (bprm->rlim_stack.rlim_cur > _STK_LIM)
1362	bprm->rlim_stack.rlim_cur = _STK_LIM;
1363	}
1364
1365	me->sas_ss_sp = me->sas_ss_size = 0;
1366
1367	/*
1368	* Figure out dumpability. Note that this checking only of current
1369	* is wrong, but userspace depends on it. This should be testing
1370	* bprm->secureexec instead.
1371	*/
1372	if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
1373	!(uid_eq(current_euid(), current_uid()) &&
1374	gid_eq(current_egid(), current_gid())))
1375	set_dumpable(current->mm, value: suid_dumpable);
1376	else
1377	set_dumpable(current->mm, SUID_DUMP_USER);
1378
1379	perf_event_exec();
1380	__set_task_comm(tsk: me, buf: kbasename(path: bprm->filename), exec: true);
1381
1382	/* An exec changes our domain. We are no longer part of the thread
1383	group */
1384	WRITE_ONCE(me->self_exec_id, me->self_exec_id + 1);
1385	flush_signal_handlers(me, force_default: 0);
1386
1387	retval = set_cred_ucounts(bprm->cred);
1388	if (retval < 0)
1389	goto out_unlock;
1390
1391	/*
1392	* install the new credentials for this executable
1393	*/
1394	security_bprm_committing_creds(bprm);
1395
1396	commit_creds(bprm->cred);
1397	bprm->cred = NULL;
1398
1399	/*
1400	* Disable monitoring for regular users
1401	* when executing setuid binaries. Must
1402	* wait until new credentials are committed
1403	* by commit_creds() above
1404	*/
1405	if (get_dumpable(mm: me->mm) != SUID_DUMP_USER)
1406	perf_event_exit_task(child: me);
1407	/*
1408	* cred_guard_mutex must be held at least to this point to prevent
1409	* ptrace_attach() from altering our determination of the task's
1410	* credentials; any time after this it may be unlocked.
1411	*/
1412	security_bprm_committed_creds(bprm);
1413
1414	/* Pass the opened binary to the interpreter. */
1415	if (bprm->have_execfd) {
1416	retval = get_unused_fd_flags(flags: 0);
1417	if (retval < 0)
1418	goto out_unlock;
1419	fd_install(fd: retval, file: bprm->executable);
1420	bprm->executable = NULL;
1421	bprm->execfd = retval;
1422	}
1423	return 0;
1424
1425	out_unlock:
1426	up_write(sem: &me->signal->exec_update_lock);
1427	if (!bprm->cred)
1428	mutex_unlock(lock: &me->signal->cred_guard_mutex);
1429
1430	out:
1431	return retval;
1432	}
1433	EXPORT_SYMBOL(begin_new_exec);
1434
1435	void would_dump(struct linux_binprm *bprm, struct file *file)
1436	{
1437	struct inode *inode = file_inode(f: file);
1438	struct mnt_idmap *idmap = file_mnt_idmap(file);
1439	if (inode_permission(idmap, inode, MAY_READ) < 0) {
1440	struct user_namespace *old, *user_ns;
1441	bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
1442
1443	/* Ensure mm->user_ns contains the executable */
1444	user_ns = old = bprm->mm->user_ns;
1445	while ((user_ns != &init_user_ns) &&
1446	!privileged_wrt_inode_uidgid(ns: user_ns, idmap, inode))
1447	user_ns = user_ns->parent;
1448
1449	if (old != user_ns) {
1450	bprm->mm->user_ns = get_user_ns(ns: user_ns);
1451	put_user_ns(ns: old);
1452	}
1453	}
1454	}
1455	EXPORT_SYMBOL(would_dump);
1456
1457	void setup_new_exec(struct linux_binprm * bprm)
1458	{
1459	/* Setup things that can depend upon the personality */
1460	struct task_struct *me = current;
1461
1462	arch_pick_mmap_layout(mm: me->mm, rlim_stack: &bprm->rlim_stack);
1463
1464	arch_setup_new_exec();
1465
1466	/* Set the new mm task size. We have to do that late because it may
1467	* depend on TIF_32BIT which is only updated in flush_thread() on
1468	* some architectures like powerpc
1469	*/
1470	me->mm->task_size = TASK_SIZE;
1471	up_write(sem: &me->signal->exec_update_lock);
1472	mutex_unlock(lock: &me->signal->cred_guard_mutex);
1473	}
1474	EXPORT_SYMBOL(setup_new_exec);
1475
1476	/* Runs immediately before start_thread() takes over. */
1477	void finalize_exec(struct linux_binprm *bprm)
1478	{
1479	/* Store any stack rlimit changes before starting thread. */
1480	task_lock(current->group_leader);
1481	current->signal->rlim[RLIMIT_STACK] = bprm->rlim_stack;
1482	task_unlock(current->group_leader);
1483	}
1484	EXPORT_SYMBOL(finalize_exec);
1485
1486	/*
1487	* Prepare credentials and lock ->cred_guard_mutex.
1488	* setup_new_exec() commits the new creds and drops the lock.
1489	* Or, if exec fails before, free_bprm() should release ->cred
1490	* and unlock.
1491	*/
1492	static int prepare_bprm_creds(struct linux_binprm *bprm)
1493	{
1494	if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
1495	return -ERESTARTNOINTR;
1496
1497	bprm->cred = prepare_exec_creds();
1498	if (likely(bprm->cred))
1499	return 0;
1500
1501	mutex_unlock(lock: &current->signal->cred_guard_mutex);
1502	return -ENOMEM;
1503	}
1504
1505	/* Matches do_open_execat() */
1506	static void do_close_execat(struct file *file)
1507	{
1508	if (!file)
1509	return;
1510	allow_write_access(file);
1511	fput(file);
1512	}
1513
1514	static void free_bprm(struct linux_binprm *bprm)
1515	{
1516	if (bprm->mm) {
1517	acct_arg_size(bprm, pages: 0);
1518	mmput(bprm->mm);
1519	}
1520	free_arg_pages(bprm);
1521	if (bprm->cred) {
1522	mutex_unlock(lock: &current->signal->cred_guard_mutex);
1523	abort_creds(bprm->cred);
1524	}
1525	do_close_execat(file: bprm->file);
1526	if (bprm->executable)
1527	fput(bprm->executable);
1528	/* If a binfmt changed the interp, free it. */
1529	if (bprm->interp != bprm->filename)
1530	kfree(objp: bprm->interp);
1531	kfree(objp: bprm->fdpath);
1532	kfree(objp: bprm);
1533	}
1534
1535	static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int flags)
1536	{
1537	struct linux_binprm *bprm;
1538	struct file *file;
1539	int retval = -ENOMEM;
1540
1541	file = do_open_execat(fd, name: filename, flags);
1542	if (IS_ERR(ptr: file))
1543	return ERR_CAST(ptr: file);
1544
1545	bprm = kzalloc(size: sizeof(*bprm), GFP_KERNEL);
1546	if (!bprm) {
1547	do_close_execat(file);
1548	return ERR_PTR(error: -ENOMEM);
1549	}
1550
1551	bprm->file = file;
1552
1553	if (fd == AT_FDCWD || filename->name[0] == '/') {
1554	bprm->filename = filename->name;
1555	} else {
1556	if (filename->name[0] == '\0')
1557	bprm->fdpath = kasprintf(GFP_KERNEL, fmt: "/dev/fd/%d", fd);
1558	else
1559	bprm->fdpath = kasprintf(GFP_KERNEL, fmt: "/dev/fd/%d/%s",
1560	fd, filename->name);
1561	if (!bprm->fdpath)
1562	goto out_free;
1563
1564	/*
1565	* Record that a name derived from an O_CLOEXEC fd will be
1566	* inaccessible after exec. This allows the code in exec to
1567	* choose to fail when the executable is not mmaped into the
1568	* interpreter and an open file descriptor is not passed to
1569	* the interpreter. This makes for a better user experience
1570	* than having the interpreter start and then immediately fail
1571	* when it finds the executable is inaccessible.
1572	*/
1573	if (get_close_on_exec(fd))
1574	bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
1575
1576	bprm->filename = bprm->fdpath;
1577	}
1578	bprm->interp = bprm->filename;
1579
1580	retval = bprm_mm_init(bprm);
1581	if (!retval)
1582	return bprm;
1583
1584	out_free:
1585	free_bprm(bprm);
1586	return ERR_PTR(error: retval);
1587	}
1588
1589	int bprm_change_interp(const char *interp, struct linux_binprm *bprm)
1590	{
1591	/* If a binfmt changed the interp, free it first. */
1592	if (bprm->interp != bprm->filename)
1593	kfree(objp: bprm->interp);
1594	bprm->interp = kstrdup(s: interp, GFP_KERNEL);
1595	if (!bprm->interp)
1596	return -ENOMEM;
1597	return 0;
1598	}
1599	EXPORT_SYMBOL(bprm_change_interp);
1600
1601	/*
1602	* determine how safe it is to execute the proposed program
1603	* - the caller must hold ->cred_guard_mutex to protect against
1604	* PTRACE_ATTACH or seccomp thread-sync
1605	*/
1606	static void check_unsafe_exec(struct linux_binprm *bprm)
1607	{
1608	struct task_struct *p = current, *t;
1609	unsigned n_fs;
1610
1611	if (p->ptrace)
1612	bprm->unsafe |= LSM_UNSAFE_PTRACE;
1613
1614	/*
1615	* This isn't strictly necessary, but it makes it harder for LSMs to
1616	* mess up.
1617	*/
1618	if (task_no_new_privs(current))
1619	bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
1620
1621	/*
1622	* If another task is sharing our fs, we cannot safely
1623	* suid exec because the differently privileged task
1624	* will be able to manipulate the current directory, etc.
1625	* It would be nice to force an unshare instead...
1626	*/
1627	n_fs = 1;
1628	spin_lock(lock: &p->fs->lock);
1629	rcu_read_lock();
1630	for_other_threads(p, t) {
1631	if (t->fs == p->fs)
1632	n_fs++;
1633	}
1634	rcu_read_unlock();
1635
1636	/* "users" and "in_exec" locked for copy_fs() */
1637	if (p->fs->users > n_fs)
1638	bprm->unsafe |= LSM_UNSAFE_SHARE;
1639	else
1640	p->fs->in_exec = 1;
1641	spin_unlock(lock: &p->fs->lock);
1642	}
1643
1644	static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)
1645	{
1646	/* Handle suid and sgid on files */
1647	struct mnt_idmap *idmap;
1648	struct inode *inode = file_inode(f: file);
1649	unsigned int mode;
1650	vfsuid_t vfsuid;
1651	vfsgid_t vfsgid;
1652
1653	if (!mnt_may_suid(mnt: file->f_path.mnt))
1654	return;
1655
1656	if (task_no_new_privs(current))
1657	return;
1658
1659	mode = READ_ONCE(inode->i_mode);
1660	if (!(mode & (S_ISUID|S_ISGID)))
1661	return;
1662
1663	idmap = file_mnt_idmap(file);
1664
1665	/* Be careful if suid/sgid is set */
1666	inode_lock(inode);
1667
1668	/* reload atomically mode/uid/gid now that lock held */
1669	mode = inode->i_mode;
1670	vfsuid = i_uid_into_vfsuid(idmap, inode);
1671	vfsgid = i_gid_into_vfsgid(idmap, inode);
1672	inode_unlock(inode);
1673
1674	/* We ignore suid/sgid if there are no mappings for them in the ns */
1675	if (!vfsuid_has_mapping(userns: bprm->cred->user_ns, vfsuid) ||
1676	!vfsgid_has_mapping(userns: bprm->cred->user_ns, vfsgid))
1677	return;
1678
1679	if (mode & S_ISUID) {
1680	bprm->per_clear |= PER_CLEAR_ON_SETID;
1681	bprm->cred->euid = vfsuid_into_kuid(vfsuid);
1682	}
1683
1684	if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1685	bprm->per_clear |= PER_CLEAR_ON_SETID;
1686	bprm->cred->egid = vfsgid_into_kgid(vfsgid);
1687	}
1688	}
1689
1690	/*
1691	* Compute brpm->cred based upon the final binary.
1692	*/
1693	static int bprm_creds_from_file(struct linux_binprm *bprm)
1694	{
1695	/* Compute creds based on which file? */
1696	struct file *file = bprm->execfd_creds ? bprm->executable : bprm->file;
1697
1698	bprm_fill_uid(bprm, file);
1699	return security_bprm_creds_from_file(bprm, file);
1700	}
1701
1702	/*
1703	* Fill the binprm structure from the inode.
1704	* Read the first BINPRM_BUF_SIZE bytes
1705	*
1706	* This may be called multiple times for binary chains (scripts for example).
1707	*/
1708	static int prepare_binprm(struct linux_binprm *bprm)
1709	{
1710	loff_t pos = 0;
1711
1712	memset(bprm->buf, 0, BINPRM_BUF_SIZE);
1713	return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
1714	}
1715
1716	/*
1717	* Arguments are '\0' separated strings found at the location bprm->p
1718	* points to; chop off the first by relocating brpm->p to right after
1719	* the first '\0' encountered.
1720	*/
1721	int remove_arg_zero(struct linux_binprm *bprm)
1722	{
1723	unsigned long offset;
1724	char *kaddr;
1725	struct page *page;
1726
1727	if (!bprm->argc)
1728	return 0;
1729
1730	do {
1731	offset = bprm->p & ~PAGE_MASK;
1732	page = get_arg_page(bprm, pos: bprm->p, write: 0);
1733	if (!page)
1734	return -EFAULT;
1735	kaddr = kmap_local_page(page);
1736
1737	for (; offset < PAGE_SIZE && kaddr[offset];
1738	offset++, bprm->p++)
1739	;
1740
1741	kunmap_local(kaddr);
1742	put_arg_page(page);
1743	} while (offset == PAGE_SIZE);
1744
1745	bprm->p++;
1746	bprm->argc--;
1747
1748	return 0;
1749	}
1750	EXPORT_SYMBOL(remove_arg_zero);
1751
1752	#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1753	/*
1754	* cycle the list of binary formats handler, until one recognizes the image
1755	*/
1756	static int search_binary_handler(struct linux_binprm *bprm)
1757	{
1758	bool need_retry = IS_ENABLED(CONFIG_MODULES);
1759	struct linux_binfmt *fmt;
1760	int retval;
1761
1762	retval = prepare_binprm(bprm);
1763	if (retval < 0)
1764	return retval;
1765
1766	retval = security_bprm_check(bprm);
1767	if (retval)
1768	return retval;
1769
1770	retval = -ENOENT;
1771	retry:
1772	read_lock(&binfmt_lock);
1773	list_for_each_entry(fmt, &formats, lh) {
1774	if (!try_module_get(module: fmt->module))
1775	continue;
1776	read_unlock(&binfmt_lock);
1777
1778	retval = fmt->load_binary(bprm);
1779
1780	read_lock(&binfmt_lock);
1781	put_binfmt(fmt);
1782	if (bprm->point_of_no_return || (retval != -ENOEXEC)) {
1783	read_unlock(&binfmt_lock);
1784	return retval;
1785	}
1786	}
1787	read_unlock(&binfmt_lock);
1788
1789	if (need_retry) {
1790	if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
1791	printable(bprm->buf[2]) && printable(bprm->buf[3]))
1792	return retval;
1793	if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
1794	return retval;
1795	need_retry = false;
1796	goto retry;
1797	}
1798
1799	return retval;
1800	}
1801
1802	/* binfmt handlers will call back into begin_new_exec() on success. */
1803	static int exec_binprm(struct linux_binprm *bprm)
1804	{
1805	pid_t old_pid, old_vpid;
1806	int ret, depth;
1807
1808	/* Need to fetch pid before load_binary changes it */
1809	old_pid = current->pid;
1810	rcu_read_lock();
1811	old_vpid = task_pid_nr_ns(current, ns: task_active_pid_ns(current->parent));
1812	rcu_read_unlock();
1813
1814	/* This allows 4 levels of binfmt rewrites before failing hard. */
1815	for (depth = 0;; depth++) {
1816	struct file *exec;
1817	if (depth > 5)
1818	return -ELOOP;
1819
1820	ret = search_binary_handler(bprm);
1821	if (ret < 0)
1822	return ret;
1823	if (!bprm->interpreter)
1824	break;
1825
1826	exec = bprm->file;
1827	bprm->file = bprm->interpreter;
1828	bprm->interpreter = NULL;
1829
1830	allow_write_access(file: exec);
1831	if (unlikely(bprm->have_execfd)) {
1832	if (bprm->executable) {
1833	fput(exec);
1834	return -ENOEXEC;
1835	}
1836	bprm->executable = exec;
1837	} else
1838	fput(exec);
1839	}
1840
1841	audit_bprm(bprm);
1842	trace_sched_process_exec(current, old_pid, bprm);
1843	ptrace_event(PTRACE_EVENT_EXEC, message: old_vpid);
1844	proc_exec_connector(current);
1845	return 0;
1846	}
1847
1848	static int bprm_execve(struct linux_binprm *bprm)
1849	{
1850	int retval;
1851
1852	retval = prepare_bprm_creds(bprm);
1853	if (retval)
1854	return retval;
1855
1856	/*
1857	* Check for unsafe execution states before exec_binprm(), which
1858	* will call back into begin_new_exec(), into bprm_creds_from_file(),
1859	* where setuid-ness is evaluated.
1860	*/
1861	check_unsafe_exec(bprm);
1862	current->in_execve = 1;
1863	sched_mm_cid_before_execve(current);
1864
1865	sched_exec();
1866
1867	/* Set the unchanging part of bprm->cred */
1868	retval = security_bprm_creds_for_exec(bprm);
1869	if (retval)
1870	goto out;
1871
1872	retval = exec_binprm(bprm);
1873	if (retval < 0)
1874	goto out;
1875
1876	sched_mm_cid_after_execve(current);
1877	/* execve succeeded */
1878	current->fs->in_exec = 0;
1879	current->in_execve = 0;
1880	rseq_execve(current);
1881	user_events_execve(current);
1882	acct_update_integrals(current);
1883	task_numa_free(current, final: false);
1884	return retval;
1885
1886	out:
1887	/*
1888	* If past the point of no return ensure the code never
1889	* returns to the userspace process. Use an existing fatal
1890	* signal if present otherwise terminate the process with
1891	* SIGSEGV.
1892	*/
1893	if (bprm->point_of_no_return && !fatal_signal_pending(current))
1894	force_fatal_sig(SIGSEGV);
1895
1896	sched_mm_cid_after_execve(current);
1897	current->fs->in_exec = 0;
1898	current->in_execve = 0;
1899
1900	return retval;
1901	}
1902
1903	static int do_execveat_common(int fd, struct filename *filename,
1904	struct user_arg_ptr argv,
1905	struct user_arg_ptr envp,
1906	int flags)
1907	{
1908	struct linux_binprm *bprm;
1909	int retval;
1910
1911	if (IS_ERR(ptr: filename))
1912	return PTR_ERR(ptr: filename);
1913
1914	/*
1915	* We move the actual failure in case of RLIMIT_NPROC excess from
1916	* set*uid() to execve() because too many poorly written programs
1917	* don't check setuid() return code. Here we additionally recheck
1918	* whether NPROC limit is still exceeded.
1919	*/
1920	if ((current->flags & PF_NPROC_EXCEEDED) &&
1921	is_rlimit_overlimit(current_ucounts(), type: UCOUNT_RLIMIT_NPROC, max: rlimit(RLIMIT_NPROC))) {
1922	retval = -EAGAIN;
1923	goto out_ret;
1924	}
1925
1926	/* We're below the limit (still or again), so we don't want to make
1927	* further execve() calls fail. */
1928	current->flags &= ~PF_NPROC_EXCEEDED;
1929
1930	bprm = alloc_bprm(fd, filename, flags);
1931	if (IS_ERR(ptr: bprm)) {
1932	retval = PTR_ERR(ptr: bprm);
1933	goto out_ret;
1934	}
1935
1936	retval = count(argv, MAX_ARG_STRINGS);
1937	if (retval == 0)
1938	pr_warn_once("process '%s' launched '%s' with NULL argv: empty string added\n",
1939	current->comm, bprm->filename);
1940	if (retval < 0)
1941	goto out_free;
1942	bprm->argc = retval;
1943
1944	retval = count(argv: envp, MAX_ARG_STRINGS);
1945	if (retval < 0)
1946	goto out_free;
1947	bprm->envc = retval;
1948
1949	retval = bprm_stack_limits(bprm);
1950	if (retval < 0)
1951	goto out_free;
1952
1953	retval = copy_string_kernel(bprm->filename, bprm);
1954	if (retval < 0)
1955	goto out_free;
1956	bprm->exec = bprm->p;
1957
1958	retval = copy_strings(argc: bprm->envc, argv: envp, bprm);
1959	if (retval < 0)
1960	goto out_free;
1961
1962	retval = copy_strings(argc: bprm->argc, argv, bprm);
1963	if (retval < 0)
1964	goto out_free;
1965
1966	/*
1967	* When argv is empty, add an empty string ("") as argv[0] to
1968	* ensure confused userspace programs that start processing
1969	* from argv[1] won't end up walking envp. See also
1970	* bprm_stack_limits().
1971	*/
1972	if (bprm->argc == 0) {
1973	retval = copy_string_kernel("", bprm);
1974	if (retval < 0)
1975	goto out_free;
1976	bprm->argc = 1;
1977	}
1978
1979	retval = bprm_execve(bprm);
1980	out_free:
1981	free_bprm(bprm);
1982
1983	out_ret:
1984	putname(name: filename);
1985	return retval;
1986	}
1987
1988	int kernel_execve(const char *kernel_filename,
1989	const char *const *argv, const char *const *envp)
1990	{
1991	struct filename *filename;
1992	struct linux_binprm *bprm;
1993	int fd = AT_FDCWD;
1994	int retval;
1995
1996	/* It is non-sense for kernel threads to call execve */
1997	if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
1998	return -EINVAL;
1999
2000	filename = getname_kernel(kernel_filename);
2001	if (IS_ERR(ptr: filename))
2002	return PTR_ERR(ptr: filename);
2003
2004	bprm = alloc_bprm(fd, filename, flags: 0);
2005	if (IS_ERR(ptr: bprm)) {
2006	retval = PTR_ERR(ptr: bprm);
2007	goto out_ret;
2008	}
2009
2010	retval = count_strings_kernel(argv);
2011	if (WARN_ON_ONCE(retval == 0))
2012	retval = -EINVAL;
2013	if (retval < 0)
2014	goto out_free;
2015	bprm->argc = retval;
2016
2017	retval = count_strings_kernel(argv: envp);
2018	if (retval < 0)
2019	goto out_free;
2020	bprm->envc = retval;
2021
2022	retval = bprm_stack_limits(bprm);
2023	if (retval < 0)
2024	goto out_free;
2025
2026	retval = copy_string_kernel(bprm->filename, bprm);
2027	if (retval < 0)
2028	goto out_free;
2029	bprm->exec = bprm->p;
2030
2031	retval = copy_strings_kernel(argc: bprm->envc, argv: envp, bprm);
2032	if (retval < 0)
2033	goto out_free;
2034
2035	retval = copy_strings_kernel(argc: bprm->argc, argv, bprm);
2036	if (retval < 0)
2037	goto out_free;
2038
2039	retval = bprm_execve(bprm);
2040	out_free:
2041	free_bprm(bprm);
2042	out_ret:
2043	putname(name: filename);
2044	return retval;
2045	}
2046
2047	static int do_execve(struct filename *filename,
2048	const char __user *const __user *__argv,
2049	const char __user *const __user *__envp)
2050	{
2051	struct user_arg_ptr argv = { .ptr.native = __argv };
2052	struct user_arg_ptr envp = { .ptr.native = __envp };
2053	return do_execveat_common(AT_FDCWD, filename, argv, envp, flags: 0);
2054	}
2055
2056	static int do_execveat(int fd, struct filename *filename,
2057	const char __user *const __user *__argv,
2058	const char __user *const __user *__envp,
2059	int flags)
2060	{
2061	struct user_arg_ptr argv = { .ptr.native = __argv };
2062	struct user_arg_ptr envp = { .ptr.native = __envp };
2063
2064	return do_execveat_common(fd, filename, argv, envp, flags);
2065	}
2066
2067	#ifdef CONFIG_COMPAT
2068	static int compat_do_execve(struct filename *filename,
2069	const compat_uptr_t __user *__argv,
2070	const compat_uptr_t __user *__envp)
2071	{
2072	struct user_arg_ptr argv = {
2073	.is_compat = true,
2074	.ptr.compat = __argv,
2075	};
2076	struct user_arg_ptr envp = {
2077	.is_compat = true,
2078	.ptr.compat = __envp,
2079	};
2080	return do_execveat_common(AT_FDCWD, filename, argv, envp, flags: 0);
2081	}
2082
2083	static int compat_do_execveat(int fd, struct filename *filename,
2084	const compat_uptr_t __user *__argv,
2085	const compat_uptr_t __user *__envp,
2086	int flags)
2087	{
2088	struct user_arg_ptr argv = {
2089	.is_compat = true,
2090	.ptr.compat = __argv,
2091	};
2092	struct user_arg_ptr envp = {
2093	.is_compat = true,
2094	.ptr.compat = __envp,
2095	};
2096	return do_execveat_common(fd, filename, argv, envp, flags);
2097	}
2098	#endif
2099
2100	void set_binfmt(struct linux_binfmt *new)
2101	{
2102	struct mm_struct *mm = current->mm;
2103
2104	if (mm->binfmt)
2105	module_put(module: mm->binfmt->module);
2106
2107	mm->binfmt = new;
2108	if (new)
2109	__module_get(module: new->module);
2110	}
2111	EXPORT_SYMBOL(set_binfmt);
2112
2113	/*
2114	* set_dumpable stores three-value SUID_DUMP_* into mm->flags.
2115	*/
2116	void set_dumpable(struct mm_struct *mm, int value)
2117	{
2118	if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
2119	return;
2120
2121	set_mask_bits(&mm->flags, MMF_DUMPABLE_MASK, value);
2122	}
2123
2124	SYSCALL_DEFINE3(execve,
2125	const char __user *, filename,
2126	const char __user *const __user *, argv,
2127	const char __user *const __user *, envp)
2128	{
2129	return do_execve(filename: getname(filename), argv: argv, envp: envp);
2130	}
2131
2132	SYSCALL_DEFINE5(execveat,
2133	int, fd, const char __user *, filename,
2134	const char __user *const __user *, argv,
2135	const char __user *const __user *, envp,
2136	int, flags)
2137	{
2138	return do_execveat(fd,
2139	filename: getname_uflags(filename, flags),
2140	argv: argv, envp: envp, flags);
2141	}
2142
2143	#ifdef CONFIG_COMPAT
2144	COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
2145	const compat_uptr_t __user *, argv,
2146	const compat_uptr_t __user *, envp)
2147	{
2148	return compat_do_execve(filename: getname(filename), argv: argv, envp: envp);
2149	}
2150
2151	COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
2152	const char __user *, filename,
2153	const compat_uptr_t __user *, argv,
2154	const compat_uptr_t __user *, envp,
2155	int, flags)
2156	{
2157	return compat_do_execveat(fd,
2158	filename: getname_uflags(filename, flags),
2159	argv: argv, envp: envp, flags);
2160	}
2161	#endif
2162
2163	#ifdef CONFIG_SYSCTL
2164
2165	static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
2166	void *buffer, size_t *lenp, loff_t *ppos)
2167	{
2168	int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
2169
2170	if (!error)
2171	validate_coredump_safety();
2172	return error;
2173	}
2174
2175	static struct ctl_table fs_exec_sysctls[] = {
2176	{
2177	.procname = "suid_dumpable",
2178	.data = &suid_dumpable,
2179	.maxlen = sizeof(int),
2180	.mode = 0644,
2181	.proc_handler = proc_dointvec_minmax_coredump,
2182	.extra1 = SYSCTL_ZERO,
2183	.extra2 = SYSCTL_TWO,
2184	},
2185	};
2186
2187	static int __init init_fs_exec_sysctls(void)
2188	{
2189	register_sysctl_init("fs", fs_exec_sysctls);
2190	return 0;
2191	}
2192
2193	fs_initcall(init_fs_exec_sysctls);
2194	#endif /* CONFIG_SYSCTL */
2195