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Commit | Line | Data |
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1 | /* | |
2 | * linux/fs/exec.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * #!-checking implemented by tytso. | |
9 | */ | |
10 | /* | |
11 | * Demand-loading implemented 01.12.91 - no need to read anything but | |
12 | * the header into memory. The inode of the executable is put into | |
13 | * "current->executable", and page faults do the actual loading. Clean. | |
14 | * | |
15 | * Once more I can proudly say that linux stood up to being changed: it | |
16 | * was less than 2 hours work to get demand-loading completely implemented. | |
17 | * | |
18 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, | |
19 | * current->executable is only used by the procfs. This allows a dispatch | |
20 | * table to check for several different types of binary formats. We keep | |
21 | * trying until we recognize the file or we run out of supported binary | |
22 | * formats. | |
23 | */ | |
24 | ||
25 | #include <linux/slab.h> | |
26 | #include <linux/file.h> | |
27 | #include <linux/fdtable.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/vmacache.h> | |
30 | #include <linux/stat.h> | |
31 | #include <linux/fcntl.h> | |
32 | #include <linux/swap.h> | |
33 | #include <linux/string.h> | |
34 | #include <linux/init.h> | |
35 | #include <linux/pagemap.h> | |
36 | #include <linux/perf_event.h> | |
37 | #include <linux/highmem.h> | |
38 | #include <linux/spinlock.h> | |
39 | #include <linux/key.h> | |
40 | #include <linux/personality.h> | |
41 | #include <linux/binfmts.h> | |
42 | #include <linux/utsname.h> | |
43 | #include <linux/pid_namespace.h> | |
44 | #include <linux/module.h> | |
45 | #include <linux/namei.h> | |
46 | #include <linux/mount.h> | |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
49 | #include <linux/tsacct_kern.h> | |
50 | #include <linux/cn_proc.h> | |
51 | #include <linux/audit.h> | |
52 | #include <linux/tracehook.h> | |
53 | #include <linux/kmod.h> | |
54 | #include <linux/fsnotify.h> | |
55 | #include <linux/fs_struct.h> | |
56 | #include <linux/pipe_fs_i.h> | |
57 | #include <linux/oom.h> | |
58 | #include <linux/compat.h> | |
59 | #include <linux/vmalloc.h> | |
60 | ||
61 | #include <asm/uaccess.h> | |
62 | #include <asm/mmu_context.h> | |
63 | #include <asm/tlb.h> | |
64 | ||
65 | #include <trace/events/task.h> | |
66 | #include "internal.h" | |
67 | ||
68 | #include <trace/events/sched.h> | |
69 | ||
70 | int suid_dumpable = 0; | |
71 | ||
72 | static LIST_HEAD(formats); | |
73 | static DEFINE_RWLOCK(binfmt_lock); | |
74 | ||
75 | void __register_binfmt(struct linux_binfmt * fmt, int insert) | |
76 | { | |
77 | BUG_ON(!fmt); | |
78 | if (WARN_ON(!fmt->load_binary)) | |
79 | return; | |
80 | write_lock(&binfmt_lock); | |
81 | insert ? list_add(&fmt->lh, &formats) : | |
82 | list_add_tail(&fmt->lh, &formats); | |
83 | write_unlock(&binfmt_lock); | |
84 | } | |
85 | ||
86 | EXPORT_SYMBOL(__register_binfmt); | |
87 | ||
88 | void unregister_binfmt(struct linux_binfmt * fmt) | |
89 | { | |
90 | write_lock(&binfmt_lock); | |
91 | list_del(&fmt->lh); | |
92 | write_unlock(&binfmt_lock); | |
93 | } | |
94 | ||
95 | EXPORT_SYMBOL(unregister_binfmt); | |
96 | ||
97 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
98 | { | |
99 | module_put(fmt->module); | |
100 | } | |
101 | ||
102 | bool path_noexec(const struct path *path) | |
103 | { | |
104 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
105 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
106 | } | |
107 | ||
108 | #ifdef CONFIG_USELIB | |
109 | /* | |
110 | * Note that a shared library must be both readable and executable due to | |
111 | * security reasons. | |
112 | * | |
113 | * Also note that we take the address to load from from the file itself. | |
114 | */ | |
115 | SYSCALL_DEFINE1(uselib, const char __user *, library) | |
116 | { | |
117 | struct linux_binfmt *fmt; | |
118 | struct file *file; | |
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, | |
126 | }; | |
127 | ||
128 | if (IS_ERR(tmp)) | |
129 | goto out; | |
130 | ||
131 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); | |
132 | putname(tmp); | |
133 | error = PTR_ERR(file); | |
134 | if (IS_ERR(file)) | |
135 | goto out; | |
136 | ||
137 | error = -EINVAL; | |
138 | if (!S_ISREG(file_inode(file)->i_mode)) | |
139 | goto exit; | |
140 | ||
141 | error = -EACCES; | |
142 | if (path_noexec(&file->f_path)) | |
143 | goto exit; | |
144 | ||
145 | fsnotify_open(file); | |
146 | ||
147 | error = -ENOEXEC; | |
148 | ||
149 | read_lock(&binfmt_lock); | |
150 | list_for_each_entry(fmt, &formats, lh) { | |
151 | if (!fmt->load_shlib) | |
152 | continue; | |
153 | if (!try_module_get(fmt->module)) | |
154 | continue; | |
155 | read_unlock(&binfmt_lock); | |
156 | error = fmt->load_shlib(file); | |
157 | read_lock(&binfmt_lock); | |
158 | put_binfmt(fmt); | |
159 | if (error != -ENOEXEC) | |
160 | break; | |
161 | } | |
162 | read_unlock(&binfmt_lock); | |
163 | exit: | |
164 | fput(file); | |
165 | out: | |
166 | return error; | |
167 | } | |
168 | #endif /* #ifdef CONFIG_USELIB */ | |
169 | ||
170 | #ifdef CONFIG_MMU | |
171 | /* | |
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). | |
176 | */ | |
177 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) | |
178 | { | |
179 | struct mm_struct *mm = current->mm; | |
180 | long diff = (long)(pages - bprm->vma_pages); | |
181 | ||
182 | if (!mm || !diff) | |
183 | return; | |
184 | ||
185 | bprm->vma_pages = pages; | |
186 | add_mm_counter(mm, MM_ANONPAGES, diff); | |
187 | } | |
188 | ||
189 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
190 | int write) | |
191 | { | |
192 | struct page *page; | |
193 | int ret; | |
194 | ||
195 | #ifdef CONFIG_STACK_GROWSUP | |
196 | if (write) { | |
197 | ret = expand_downwards(bprm->vma, pos); | |
198 | if (ret < 0) | |
199 | return NULL; | |
200 | } | |
201 | #endif | |
202 | /* | |
203 | * We are doing an exec(). 'current' is the process | |
204 | * doing the exec and bprm->mm is the new process's mm. | |
205 | */ | |
206 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, write, | |
207 | 1, &page, NULL); | |
208 | if (ret <= 0) | |
209 | return NULL; | |
210 | ||
211 | if (write) { | |
212 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
213 | struct rlimit *rlim; | |
214 | ||
215 | acct_arg_size(bprm, size / PAGE_SIZE); | |
216 | ||
217 | /* | |
218 | * We've historically supported up to 32 pages (ARG_MAX) | |
219 | * of argument strings even with small stacks | |
220 | */ | |
221 | if (size <= ARG_MAX) | |
222 | return page; | |
223 | ||
224 | /* | |
225 | * Limit to 1/4-th the stack size for the argv+env strings. | |
226 | * This ensures that: | |
227 | * - the remaining binfmt code will not run out of stack space, | |
228 | * - the program will have a reasonable amount of stack left | |
229 | * to work from. | |
230 | */ | |
231 | rlim = current->signal->rlim; | |
232 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { | |
233 | put_page(page); | |
234 | return NULL; | |
235 | } | |
236 | } | |
237 | ||
238 | return page; | |
239 | } | |
240 | ||
241 | static void put_arg_page(struct page *page) | |
242 | { | |
243 | put_page(page); | |
244 | } | |
245 | ||
246 | static void free_arg_pages(struct linux_binprm *bprm) | |
247 | { | |
248 | } | |
249 | ||
250 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
251 | struct page *page) | |
252 | { | |
253 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
254 | } | |
255 | ||
256 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
257 | { | |
258 | int err; | |
259 | struct vm_area_struct *vma = NULL; | |
260 | struct mm_struct *mm = bprm->mm; | |
261 | ||
262 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
263 | if (!vma) | |
264 | return -ENOMEM; | |
265 | ||
266 | if (down_write_killable(&mm->mmap_sem)) { | |
267 | err = -EINTR; | |
268 | goto err_free; | |
269 | } | |
270 | vma->vm_mm = mm; | |
271 | ||
272 | /* | |
273 | * Place the stack at the largest stack address the architecture | |
274 | * supports. Later, we'll move this to an appropriate place. We don't | |
275 | * use STACK_TOP because that can depend on attributes which aren't | |
276 | * configured yet. | |
277 | */ | |
278 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); | |
279 | vma->vm_end = STACK_TOP_MAX; | |
280 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
281 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; | |
282 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); | |
283 | INIT_LIST_HEAD(&vma->anon_vma_chain); | |
284 | ||
285 | err = insert_vm_struct(mm, vma); | |
286 | if (err) | |
287 | goto err; | |
288 | ||
289 | mm->stack_vm = mm->total_vm = 1; | |
290 | arch_bprm_mm_init(mm, vma); | |
291 | up_write(&mm->mmap_sem); | |
292 | bprm->p = vma->vm_end - sizeof(void *); | |
293 | return 0; | |
294 | err: | |
295 | up_write(&mm->mmap_sem); | |
296 | err_free: | |
297 | bprm->vma = NULL; | |
298 | kmem_cache_free(vm_area_cachep, vma); | |
299 | return err; | |
300 | } | |
301 | ||
302 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
303 | { | |
304 | return len <= MAX_ARG_STRLEN; | |
305 | } | |
306 | ||
307 | #else | |
308 | ||
309 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) | |
310 | { | |
311 | } | |
312 | ||
313 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
314 | int write) | |
315 | { | |
316 | struct page *page; | |
317 | ||
318 | page = bprm->page[pos / PAGE_SIZE]; | |
319 | if (!page && write) { | |
320 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
321 | if (!page) | |
322 | return NULL; | |
323 | bprm->page[pos / PAGE_SIZE] = page; | |
324 | } | |
325 | ||
326 | return page; | |
327 | } | |
328 | ||
329 | static void put_arg_page(struct page *page) | |
330 | { | |
331 | } | |
332 | ||
333 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
334 | { | |
335 | if (bprm->page[i]) { | |
336 | __free_page(bprm->page[i]); | |
337 | bprm->page[i] = NULL; | |
338 | } | |
339 | } | |
340 | ||
341 | static void free_arg_pages(struct linux_binprm *bprm) | |
342 | { | |
343 | int i; | |
344 | ||
345 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
346 | free_arg_page(bprm, i); | |
347 | } | |
348 | ||
349 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
350 | struct page *page) | |
351 | { | |
352 | } | |
353 | ||
354 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
355 | { | |
356 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
357 | return 0; | |
358 | } | |
359 | ||
360 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
361 | { | |
362 | return len <= bprm->p; | |
363 | } | |
364 | ||
365 | #endif /* CONFIG_MMU */ | |
366 | ||
367 | /* | |
368 | * Create a new mm_struct and populate it with a temporary stack | |
369 | * vm_area_struct. We don't have enough context at this point to set the stack | |
370 | * flags, permissions, and offset, so we use temporary values. We'll update | |
371 | * them later in setup_arg_pages(). | |
372 | */ | |
373 | static int bprm_mm_init(struct linux_binprm *bprm) | |
374 | { | |
375 | int err; | |
376 | struct mm_struct *mm = NULL; | |
377 | ||
378 | bprm->mm = mm = mm_alloc(); | |
379 | err = -ENOMEM; | |
380 | if (!mm) | |
381 | goto err; | |
382 | ||
383 | err = __bprm_mm_init(bprm); | |
384 | if (err) | |
385 | goto err; | |
386 | ||
387 | return 0; | |
388 | ||
389 | err: | |
390 | if (mm) { | |
391 | bprm->mm = NULL; | |
392 | mmdrop(mm); | |
393 | } | |
394 | ||
395 | return err; | |
396 | } | |
397 | ||
398 | struct user_arg_ptr { | |
399 | #ifdef CONFIG_COMPAT | |
400 | bool is_compat; | |
401 | #endif | |
402 | union { | |
403 | const char __user *const __user *native; | |
404 | #ifdef CONFIG_COMPAT | |
405 | const compat_uptr_t __user *compat; | |
406 | #endif | |
407 | } ptr; | |
408 | }; | |
409 | ||
410 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
411 | { | |
412 | const char __user *native; | |
413 | ||
414 | #ifdef CONFIG_COMPAT | |
415 | if (unlikely(argv.is_compat)) { | |
416 | compat_uptr_t compat; | |
417 | ||
418 | if (get_user(compat, argv.ptr.compat + nr)) | |
419 | return ERR_PTR(-EFAULT); | |
420 | ||
421 | return compat_ptr(compat); | |
422 | } | |
423 | #endif | |
424 | ||
425 | if (get_user(native, argv.ptr.native + nr)) | |
426 | return ERR_PTR(-EFAULT); | |
427 | ||
428 | return native; | |
429 | } | |
430 | ||
431 | /* | |
432 | * count() counts the number of strings in array ARGV. | |
433 | */ | |
434 | static int count(struct user_arg_ptr argv, int max) | |
435 | { | |
436 | int i = 0; | |
437 | ||
438 | if (argv.ptr.native != NULL) { | |
439 | for (;;) { | |
440 | const char __user *p = get_user_arg_ptr(argv, i); | |
441 | ||
442 | if (!p) | |
443 | break; | |
444 | ||
445 | if (IS_ERR(p)) | |
446 | return -EFAULT; | |
447 | ||
448 | if (i >= max) | |
449 | return -E2BIG; | |
450 | ++i; | |
451 | ||
452 | if (fatal_signal_pending(current)) | |
453 | return -ERESTARTNOHAND; | |
454 | cond_resched(); | |
455 | } | |
456 | } | |
457 | return i; | |
458 | } | |
459 | ||
460 | /* | |
461 | * 'copy_strings()' copies argument/environment strings from the old | |
462 | * processes's memory to the new process's stack. The call to get_user_pages() | |
463 | * ensures the destination page is created and not swapped out. | |
464 | */ | |
465 | static int copy_strings(int argc, struct user_arg_ptr argv, | |
466 | struct linux_binprm *bprm) | |
467 | { | |
468 | struct page *kmapped_page = NULL; | |
469 | char *kaddr = NULL; | |
470 | unsigned long kpos = 0; | |
471 | int ret; | |
472 | ||
473 | while (argc-- > 0) { | |
474 | const char __user *str; | |
475 | int len; | |
476 | unsigned long pos; | |
477 | ||
478 | ret = -EFAULT; | |
479 | str = get_user_arg_ptr(argv, argc); | |
480 | if (IS_ERR(str)) | |
481 | goto out; | |
482 | ||
483 | len = strnlen_user(str, MAX_ARG_STRLEN); | |
484 | if (!len) | |
485 | goto out; | |
486 | ||
487 | ret = -E2BIG; | |
488 | if (!valid_arg_len(bprm, len)) | |
489 | goto out; | |
490 | ||
491 | /* We're going to work our way backwords. */ | |
492 | pos = bprm->p; | |
493 | str += len; | |
494 | bprm->p -= len; | |
495 | ||
496 | while (len > 0) { | |
497 | int offset, bytes_to_copy; | |
498 | ||
499 | if (fatal_signal_pending(current)) { | |
500 | ret = -ERESTARTNOHAND; | |
501 | goto out; | |
502 | } | |
503 | cond_resched(); | |
504 | ||
505 | offset = pos % PAGE_SIZE; | |
506 | if (offset == 0) | |
507 | offset = PAGE_SIZE; | |
508 | ||
509 | bytes_to_copy = offset; | |
510 | if (bytes_to_copy > len) | |
511 | bytes_to_copy = len; | |
512 | ||
513 | offset -= bytes_to_copy; | |
514 | pos -= bytes_to_copy; | |
515 | str -= bytes_to_copy; | |
516 | len -= bytes_to_copy; | |
517 | ||
518 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
519 | struct page *page; | |
520 | ||
521 | page = get_arg_page(bprm, pos, 1); | |
522 | if (!page) { | |
523 | ret = -E2BIG; | |
524 | goto out; | |
525 | } | |
526 | ||
527 | if (kmapped_page) { | |
528 | flush_kernel_dcache_page(kmapped_page); | |
529 | kunmap(kmapped_page); | |
530 | put_arg_page(kmapped_page); | |
531 | } | |
532 | kmapped_page = page; | |
533 | kaddr = kmap(kmapped_page); | |
534 | kpos = pos & PAGE_MASK; | |
535 | flush_arg_page(bprm, kpos, kmapped_page); | |
536 | } | |
537 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { | |
538 | ret = -EFAULT; | |
539 | goto out; | |
540 | } | |
541 | } | |
542 | } | |
543 | ret = 0; | |
544 | out: | |
545 | if (kmapped_page) { | |
546 | flush_kernel_dcache_page(kmapped_page); | |
547 | kunmap(kmapped_page); | |
548 | put_arg_page(kmapped_page); | |
549 | } | |
550 | return ret; | |
551 | } | |
552 | ||
553 | /* | |
554 | * Like copy_strings, but get argv and its values from kernel memory. | |
555 | */ | |
556 | int copy_strings_kernel(int argc, const char *const *__argv, | |
557 | struct linux_binprm *bprm) | |
558 | { | |
559 | int r; | |
560 | mm_segment_t oldfs = get_fs(); | |
561 | struct user_arg_ptr argv = { | |
562 | .ptr.native = (const char __user *const __user *)__argv, | |
563 | }; | |
564 | ||
565 | set_fs(KERNEL_DS); | |
566 | r = copy_strings(argc, argv, bprm); | |
567 | set_fs(oldfs); | |
568 | ||
569 | return r; | |
570 | } | |
571 | EXPORT_SYMBOL(copy_strings_kernel); | |
572 | ||
573 | #ifdef CONFIG_MMU | |
574 | ||
575 | /* | |
576 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once | |
577 | * the binfmt code determines where the new stack should reside, we shift it to | |
578 | * its final location. The process proceeds as follows: | |
579 | * | |
580 | * 1) Use shift to calculate the new vma endpoints. | |
581 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
582 | * arguments passed to subsequent functions are consistent. | |
583 | * 3) Move vma's page tables to the new range. | |
584 | * 4) Free up any cleared pgd range. | |
585 | * 5) Shrink the vma to cover only the new range. | |
586 | */ | |
587 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) | |
588 | { | |
589 | struct mm_struct *mm = vma->vm_mm; | |
590 | unsigned long old_start = vma->vm_start; | |
591 | unsigned long old_end = vma->vm_end; | |
592 | unsigned long length = old_end - old_start; | |
593 | unsigned long new_start = old_start - shift; | |
594 | unsigned long new_end = old_end - shift; | |
595 | struct mmu_gather tlb; | |
596 | ||
597 | BUG_ON(new_start > new_end); | |
598 | ||
599 | /* | |
600 | * ensure there are no vmas between where we want to go | |
601 | * and where we are | |
602 | */ | |
603 | if (vma != find_vma(mm, new_start)) | |
604 | return -EFAULT; | |
605 | ||
606 | /* | |
607 | * cover the whole range: [new_start, old_end) | |
608 | */ | |
609 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) | |
610 | return -ENOMEM; | |
611 | ||
612 | /* | |
613 | * move the page tables downwards, on failure we rely on | |
614 | * process cleanup to remove whatever mess we made. | |
615 | */ | |
616 | if (length != move_page_tables(vma, old_start, | |
617 | vma, new_start, length, false)) | |
618 | return -ENOMEM; | |
619 | ||
620 | lru_add_drain(); | |
621 | tlb_gather_mmu(&tlb, mm, old_start, old_end); | |
622 | if (new_end > old_start) { | |
623 | /* | |
624 | * when the old and new regions overlap clear from new_end. | |
625 | */ | |
626 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
627 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
628 | } else { | |
629 | /* | |
630 | * otherwise, clean from old_start; this is done to not touch | |
631 | * the address space in [new_end, old_start) some architectures | |
632 | * have constraints on va-space that make this illegal (IA64) - | |
633 | * for the others its just a little faster. | |
634 | */ | |
635 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
636 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
637 | } | |
638 | tlb_finish_mmu(&tlb, old_start, old_end); | |
639 | ||
640 | /* | |
641 | * Shrink the vma to just the new range. Always succeeds. | |
642 | */ | |
643 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
644 | ||
645 | return 0; | |
646 | } | |
647 | ||
648 | /* | |
649 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
650 | * the stack is optionally relocated, and some extra space is added. | |
651 | */ | |
652 | int setup_arg_pages(struct linux_binprm *bprm, | |
653 | unsigned long stack_top, | |
654 | int executable_stack) | |
655 | { | |
656 | unsigned long ret; | |
657 | unsigned long stack_shift; | |
658 | struct mm_struct *mm = current->mm; | |
659 | struct vm_area_struct *vma = bprm->vma; | |
660 | struct vm_area_struct *prev = NULL; | |
661 | unsigned long vm_flags; | |
662 | unsigned long stack_base; | |
663 | unsigned long stack_size; | |
664 | unsigned long stack_expand; | |
665 | unsigned long rlim_stack; | |
666 | ||
667 | #ifdef CONFIG_STACK_GROWSUP | |
668 | /* Limit stack size */ | |
669 | stack_base = rlimit_max(RLIMIT_STACK); | |
670 | if (stack_base > STACK_SIZE_MAX) | |
671 | stack_base = STACK_SIZE_MAX; | |
672 | ||
673 | /* Add space for stack randomization. */ | |
674 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
675 | ||
676 | /* Make sure we didn't let the argument array grow too large. */ | |
677 | if (vma->vm_end - vma->vm_start > stack_base) | |
678 | return -ENOMEM; | |
679 | ||
680 | stack_base = PAGE_ALIGN(stack_top - stack_base); | |
681 | ||
682 | stack_shift = vma->vm_start - stack_base; | |
683 | mm->arg_start = bprm->p - stack_shift; | |
684 | bprm->p = vma->vm_end - stack_shift; | |
685 | #else | |
686 | stack_top = arch_align_stack(stack_top); | |
687 | stack_top = PAGE_ALIGN(stack_top); | |
688 | ||
689 | if (unlikely(stack_top < mmap_min_addr) || | |
690 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
691 | return -ENOMEM; | |
692 | ||
693 | stack_shift = vma->vm_end - stack_top; | |
694 | ||
695 | bprm->p -= stack_shift; | |
696 | mm->arg_start = bprm->p; | |
697 | #endif | |
698 | ||
699 | if (bprm->loader) | |
700 | bprm->loader -= stack_shift; | |
701 | bprm->exec -= stack_shift; | |
702 | ||
703 | if (down_write_killable(&mm->mmap_sem)) | |
704 | return -EINTR; | |
705 | ||
706 | vm_flags = VM_STACK_FLAGS; | |
707 | ||
708 | /* | |
709 | * Adjust stack execute permissions; explicitly enable for | |
710 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
711 | * (arch default) otherwise. | |
712 | */ | |
713 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
714 | vm_flags |= VM_EXEC; | |
715 | else if (executable_stack == EXSTACK_DISABLE_X) | |
716 | vm_flags &= ~VM_EXEC; | |
717 | vm_flags |= mm->def_flags; | |
718 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; | |
719 | ||
720 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
721 | vm_flags); | |
722 | if (ret) | |
723 | goto out_unlock; | |
724 | BUG_ON(prev != vma); | |
725 | ||
726 | /* Move stack pages down in memory. */ | |
727 | if (stack_shift) { | |
728 | ret = shift_arg_pages(vma, stack_shift); | |
729 | if (ret) | |
730 | goto out_unlock; | |
731 | } | |
732 | ||
733 | /* mprotect_fixup is overkill to remove the temporary stack flags */ | |
734 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
735 | ||
736 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ | |
737 | stack_size = vma->vm_end - vma->vm_start; | |
738 | /* | |
739 | * Align this down to a page boundary as expand_stack | |
740 | * will align it up. | |
741 | */ | |
742 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
743 | #ifdef CONFIG_STACK_GROWSUP | |
744 | if (stack_size + stack_expand > rlim_stack) | |
745 | stack_base = vma->vm_start + rlim_stack; | |
746 | else | |
747 | stack_base = vma->vm_end + stack_expand; | |
748 | #else | |
749 | if (stack_size + stack_expand > rlim_stack) | |
750 | stack_base = vma->vm_end - rlim_stack; | |
751 | else | |
752 | stack_base = vma->vm_start - stack_expand; | |
753 | #endif | |
754 | current->mm->start_stack = bprm->p; | |
755 | ret = expand_stack(vma, stack_base); | |
756 | if (ret) | |
757 | ret = -EFAULT; | |
758 | ||
759 | out_unlock: | |
760 | up_write(&mm->mmap_sem); | |
761 | return ret; | |
762 | } | |
763 | EXPORT_SYMBOL(setup_arg_pages); | |
764 | ||
765 | #else | |
766 | ||
767 | /* | |
768 | * Transfer the program arguments and environment from the holding pages | |
769 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
770 | */ | |
771 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
772 | unsigned long *sp_location) | |
773 | { | |
774 | unsigned long index, stop, sp; | |
775 | int ret = 0; | |
776 | ||
777 | stop = bprm->p >> PAGE_SHIFT; | |
778 | sp = *sp_location; | |
779 | ||
780 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
781 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
782 | char *src = kmap(bprm->page[index]) + offset; | |
783 | sp -= PAGE_SIZE - offset; | |
784 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
785 | ret = -EFAULT; | |
786 | kunmap(bprm->page[index]); | |
787 | if (ret) | |
788 | goto out; | |
789 | } | |
790 | ||
791 | *sp_location = sp; | |
792 | ||
793 | out: | |
794 | return ret; | |
795 | } | |
796 | EXPORT_SYMBOL(transfer_args_to_stack); | |
797 | ||
798 | #endif /* CONFIG_MMU */ | |
799 | ||
800 | static struct file *do_open_execat(int fd, struct filename *name, int flags) | |
801 | { | |
802 | struct file *file; | |
803 | int err; | |
804 | struct open_flags open_exec_flags = { | |
805 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
806 | .acc_mode = MAY_EXEC, | |
807 | .intent = LOOKUP_OPEN, | |
808 | .lookup_flags = LOOKUP_FOLLOW, | |
809 | }; | |
810 | ||
811 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) | |
812 | return ERR_PTR(-EINVAL); | |
813 | if (flags & AT_SYMLINK_NOFOLLOW) | |
814 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
815 | if (flags & AT_EMPTY_PATH) | |
816 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
817 | ||
818 | file = do_filp_open(fd, name, &open_exec_flags); | |
819 | if (IS_ERR(file)) | |
820 | goto out; | |
821 | ||
822 | err = -EACCES; | |
823 | if (!S_ISREG(file_inode(file)->i_mode)) | |
824 | goto exit; | |
825 | ||
826 | if (path_noexec(&file->f_path)) | |
827 | goto exit; | |
828 | ||
829 | err = deny_write_access(file); | |
830 | if (err) | |
831 | goto exit; | |
832 | ||
833 | if (name->name[0] != '\0') | |
834 | fsnotify_open(file); | |
835 | ||
836 | out: | |
837 | return file; | |
838 | ||
839 | exit: | |
840 | fput(file); | |
841 | return ERR_PTR(err); | |
842 | } | |
843 | ||
844 | struct file *open_exec(const char *name) | |
845 | { | |
846 | struct filename *filename = getname_kernel(name); | |
847 | struct file *f = ERR_CAST(filename); | |
848 | ||
849 | if (!IS_ERR(filename)) { | |
850 | f = do_open_execat(AT_FDCWD, filename, 0); | |
851 | putname(filename); | |
852 | } | |
853 | return f; | |
854 | } | |
855 | EXPORT_SYMBOL(open_exec); | |
856 | ||
857 | int kernel_read(struct file *file, loff_t offset, | |
858 | char *addr, unsigned long count) | |
859 | { | |
860 | mm_segment_t old_fs; | |
861 | loff_t pos = offset; | |
862 | int result; | |
863 | ||
864 | old_fs = get_fs(); | |
865 | set_fs(get_ds()); | |
866 | /* The cast to a user pointer is valid due to the set_fs() */ | |
867 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
868 | set_fs(old_fs); | |
869 | return result; | |
870 | } | |
871 | ||
872 | EXPORT_SYMBOL(kernel_read); | |
873 | ||
874 | int kernel_read_file(struct file *file, void **buf, loff_t *size, | |
875 | loff_t max_size, enum kernel_read_file_id id) | |
876 | { | |
877 | loff_t i_size, pos; | |
878 | ssize_t bytes = 0; | |
879 | int ret; | |
880 | ||
881 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
882 | return -EINVAL; | |
883 | ||
884 | ret = security_kernel_read_file(file, id); | |
885 | if (ret) | |
886 | return ret; | |
887 | ||
888 | ret = deny_write_access(file); | |
889 | if (ret) | |
890 | return ret; | |
891 | ||
892 | i_size = i_size_read(file_inode(file)); | |
893 | if (max_size > 0 && i_size > max_size) { | |
894 | ret = -EFBIG; | |
895 | goto out; | |
896 | } | |
897 | if (i_size <= 0) { | |
898 | ret = -EINVAL; | |
899 | goto out; | |
900 | } | |
901 | ||
902 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) | |
903 | *buf = vmalloc(i_size); | |
904 | if (!*buf) { | |
905 | ret = -ENOMEM; | |
906 | goto out; | |
907 | } | |
908 | ||
909 | pos = 0; | |
910 | while (pos < i_size) { | |
911 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
912 | i_size - pos); | |
913 | if (bytes < 0) { | |
914 | ret = bytes; | |
915 | goto out; | |
916 | } | |
917 | ||
918 | if (bytes == 0) | |
919 | break; | |
920 | pos += bytes; | |
921 | } | |
922 | ||
923 | if (pos != i_size) { | |
924 | ret = -EIO; | |
925 | goto out_free; | |
926 | } | |
927 | ||
928 | ret = security_kernel_post_read_file(file, *buf, i_size, id); | |
929 | if (!ret) | |
930 | *size = pos; | |
931 | ||
932 | out_free: | |
933 | if (ret < 0) { | |
934 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { | |
935 | vfree(*buf); | |
936 | *buf = NULL; | |
937 | } | |
938 | } | |
939 | ||
940 | out: | |
941 | allow_write_access(file); | |
942 | return ret; | |
943 | } | |
944 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
945 | ||
946 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, | |
947 | loff_t max_size, enum kernel_read_file_id id) | |
948 | { | |
949 | struct file *file; | |
950 | int ret; | |
951 | ||
952 | if (!path || !*path) | |
953 | return -EINVAL; | |
954 | ||
955 | file = filp_open(path, O_RDONLY, 0); | |
956 | if (IS_ERR(file)) | |
957 | return PTR_ERR(file); | |
958 | ||
959 | ret = kernel_read_file(file, buf, size, max_size, id); | |
960 | fput(file); | |
961 | return ret; | |
962 | } | |
963 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
964 | ||
965 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, | |
966 | enum kernel_read_file_id id) | |
967 | { | |
968 | struct fd f = fdget(fd); | |
969 | int ret = -EBADF; | |
970 | ||
971 | if (!f.file) | |
972 | goto out; | |
973 | ||
974 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
975 | out: | |
976 | fdput(f); | |
977 | return ret; | |
978 | } | |
979 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
980 | ||
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_range(addr, addr + len); | |
986 | return res; | |
987 | } | |
988 | EXPORT_SYMBOL(read_code); | |
989 | ||
990 | static int exec_mmap(struct mm_struct *mm) | |
991 | { | |
992 | struct task_struct *tsk; | |
993 | struct mm_struct *old_mm, *active_mm; | |
994 | ||
995 | /* Notify parent that we're no longer interested in the old VM */ | |
996 | tsk = current; | |
997 | old_mm = current->mm; | |
998 | mm_release(tsk, old_mm); | |
999 | ||
1000 | if (old_mm) { | |
1001 | sync_mm_rss(old_mm); | |
1002 | /* | |
1003 | * Make sure that if there is a core dump in progress | |
1004 | * for the old mm, we get out and die instead of going | |
1005 | * through with the exec. We must hold mmap_sem around | |
1006 | * checking core_state and changing tsk->mm. | |
1007 | */ | |
1008 | down_read(&old_mm->mmap_sem); | |
1009 | if (unlikely(old_mm->core_state)) { | |
1010 | up_read(&old_mm->mmap_sem); | |
1011 | return -EINTR; | |
1012 | } | |
1013 | } | |
1014 | task_lock(tsk); | |
1015 | active_mm = tsk->active_mm; | |
1016 | tsk->mm = mm; | |
1017 | tsk->active_mm = mm; | |
1018 | activate_mm(active_mm, mm); | |
1019 | tsk->mm->vmacache_seqnum = 0; | |
1020 | vmacache_flush(tsk); | |
1021 | task_unlock(tsk); | |
1022 | if (old_mm) { | |
1023 | up_read(&old_mm->mmap_sem); | |
1024 | BUG_ON(active_mm != old_mm); | |
1025 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); | |
1026 | mm_update_next_owner(old_mm); | |
1027 | mmput(old_mm); | |
1028 | return 0; | |
1029 | } | |
1030 | mmdrop(active_mm); | |
1031 | return 0; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * This function makes sure the current process has its own signal table, | |
1036 | * so that flush_signal_handlers can later reset the handlers without | |
1037 | * disturbing other processes. (Other processes might share the signal | |
1038 | * table via the CLONE_SIGHAND option to clone().) | |
1039 | */ | |
1040 | static int de_thread(struct task_struct *tsk) | |
1041 | { | |
1042 | struct signal_struct *sig = tsk->signal; | |
1043 | struct sighand_struct *oldsighand = tsk->sighand; | |
1044 | spinlock_t *lock = &oldsighand->siglock; | |
1045 | ||
1046 | if (thread_group_empty(tsk)) | |
1047 | goto no_thread_group; | |
1048 | ||
1049 | /* | |
1050 | * Kill all other threads in the thread group. | |
1051 | */ | |
1052 | spin_lock_irq(lock); | |
1053 | if (signal_group_exit(sig)) { | |
1054 | /* | |
1055 | * Another group action in progress, just | |
1056 | * return so that the signal is processed. | |
1057 | */ | |
1058 | spin_unlock_irq(lock); | |
1059 | return -EAGAIN; | |
1060 | } | |
1061 | ||
1062 | sig->group_exit_task = tsk; | |
1063 | sig->notify_count = zap_other_threads(tsk); | |
1064 | if (!thread_group_leader(tsk)) | |
1065 | sig->notify_count--; | |
1066 | ||
1067 | while (sig->notify_count) { | |
1068 | __set_current_state(TASK_KILLABLE); | |
1069 | spin_unlock_irq(lock); | |
1070 | schedule(); | |
1071 | if (unlikely(__fatal_signal_pending(tsk))) | |
1072 | goto killed; | |
1073 | spin_lock_irq(lock); | |
1074 | } | |
1075 | spin_unlock_irq(lock); | |
1076 | ||
1077 | /* | |
1078 | * At this point all other threads have exited, all we have to | |
1079 | * do is to wait for the thread group leader to become inactive, | |
1080 | * and to assume its PID: | |
1081 | */ | |
1082 | if (!thread_group_leader(tsk)) { | |
1083 | struct task_struct *leader = tsk->group_leader; | |
1084 | ||
1085 | for (;;) { | |
1086 | threadgroup_change_begin(tsk); | |
1087 | write_lock_irq(&tasklist_lock); | |
1088 | /* | |
1089 | * Do this under tasklist_lock to ensure that | |
1090 | * exit_notify() can't miss ->group_exit_task | |
1091 | */ | |
1092 | sig->notify_count = -1; | |
1093 | if (likely(leader->exit_state)) | |
1094 | break; | |
1095 | __set_current_state(TASK_KILLABLE); | |
1096 | write_unlock_irq(&tasklist_lock); | |
1097 | threadgroup_change_end(tsk); | |
1098 | schedule(); | |
1099 | if (unlikely(__fatal_signal_pending(tsk))) | |
1100 | goto killed; | |
1101 | } | |
1102 | ||
1103 | /* | |
1104 | * The only record we have of the real-time age of a | |
1105 | * process, regardless of execs it's done, is start_time. | |
1106 | * All the past CPU time is accumulated in signal_struct | |
1107 | * from sister threads now dead. But in this non-leader | |
1108 | * exec, nothing survives from the original leader thread, | |
1109 | * whose birth marks the true age of this process now. | |
1110 | * When we take on its identity by switching to its PID, we | |
1111 | * also take its birthdate (always earlier than our own). | |
1112 | */ | |
1113 | tsk->start_time = leader->start_time; | |
1114 | tsk->real_start_time = leader->real_start_time; | |
1115 | ||
1116 | BUG_ON(!same_thread_group(leader, tsk)); | |
1117 | BUG_ON(has_group_leader_pid(tsk)); | |
1118 | /* | |
1119 | * An exec() starts a new thread group with the | |
1120 | * TGID of the previous thread group. Rehash the | |
1121 | * two threads with a switched PID, and release | |
1122 | * the former thread group leader: | |
1123 | */ | |
1124 | ||
1125 | /* Become a process group leader with the old leader's pid. | |
1126 | * The old leader becomes a thread of the this thread group. | |
1127 | * Note: The old leader also uses this pid until release_task | |
1128 | * is called. Odd but simple and correct. | |
1129 | */ | |
1130 | tsk->pid = leader->pid; | |
1131 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); | |
1132 | transfer_pid(leader, tsk, PIDTYPE_PGID); | |
1133 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
1134 | ||
1135 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1136 | list_replace_init(&leader->sibling, &tsk->sibling); | |
1137 | ||
1138 | tsk->group_leader = tsk; | |
1139 | leader->group_leader = tsk; | |
1140 | ||
1141 | tsk->exit_signal = SIGCHLD; | |
1142 | leader->exit_signal = -1; | |
1143 | ||
1144 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1145 | leader->exit_state = EXIT_DEAD; | |
1146 | ||
1147 | /* | |
1148 | * We are going to release_task()->ptrace_unlink() silently, | |
1149 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1150 | * the tracer wont't block again waiting for this thread. | |
1151 | */ | |
1152 | if (unlikely(leader->ptrace)) | |
1153 | __wake_up_parent(leader, leader->parent); | |
1154 | write_unlock_irq(&tasklist_lock); | |
1155 | threadgroup_change_end(tsk); | |
1156 | ||
1157 | release_task(leader); | |
1158 | } | |
1159 | ||
1160 | sig->group_exit_task = NULL; | |
1161 | sig->notify_count = 0; | |
1162 | ||
1163 | no_thread_group: | |
1164 | /* we have changed execution domain */ | |
1165 | tsk->exit_signal = SIGCHLD; | |
1166 | ||
1167 | exit_itimers(sig); | |
1168 | flush_itimer_signals(); | |
1169 | ||
1170 | if (atomic_read(&oldsighand->count) != 1) { | |
1171 | struct sighand_struct *newsighand; | |
1172 | /* | |
1173 | * This ->sighand is shared with the CLONE_SIGHAND | |
1174 | * but not CLONE_THREAD task, switch to the new one. | |
1175 | */ | |
1176 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
1177 | if (!newsighand) | |
1178 | return -ENOMEM; | |
1179 | ||
1180 | atomic_set(&newsighand->count, 1); | |
1181 | memcpy(newsighand->action, oldsighand->action, | |
1182 | sizeof(newsighand->action)); | |
1183 | ||
1184 | write_lock_irq(&tasklist_lock); | |
1185 | spin_lock(&oldsighand->siglock); | |
1186 | rcu_assign_pointer(tsk->sighand, newsighand); | |
1187 | spin_unlock(&oldsighand->siglock); | |
1188 | write_unlock_irq(&tasklist_lock); | |
1189 | ||
1190 | __cleanup_sighand(oldsighand); | |
1191 | } | |
1192 | ||
1193 | BUG_ON(!thread_group_leader(tsk)); | |
1194 | return 0; | |
1195 | ||
1196 | killed: | |
1197 | /* protects against exit_notify() and __exit_signal() */ | |
1198 | read_lock(&tasklist_lock); | |
1199 | sig->group_exit_task = NULL; | |
1200 | sig->notify_count = 0; | |
1201 | read_unlock(&tasklist_lock); | |
1202 | return -EAGAIN; | |
1203 | } | |
1204 | ||
1205 | char *get_task_comm(char *buf, struct task_struct *tsk) | |
1206 | { | |
1207 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1208 | task_lock(tsk); | |
1209 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1210 | task_unlock(tsk); | |
1211 | return buf; | |
1212 | } | |
1213 | EXPORT_SYMBOL_GPL(get_task_comm); | |
1214 | ||
1215 | /* | |
1216 | * These functions flushes out all traces of the currently running executable | |
1217 | * so that a new one can be started | |
1218 | */ | |
1219 | ||
1220 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) | |
1221 | { | |
1222 | task_lock(tsk); | |
1223 | trace_task_rename(tsk, buf); | |
1224 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
1225 | task_unlock(tsk); | |
1226 | perf_event_comm(tsk, exec); | |
1227 | } | |
1228 | ||
1229 | int flush_old_exec(struct linux_binprm * bprm) | |
1230 | { | |
1231 | int retval; | |
1232 | ||
1233 | /* | |
1234 | * Make sure we have a private signal table and that | |
1235 | * we are unassociated from the previous thread group. | |
1236 | */ | |
1237 | retval = de_thread(current); | |
1238 | if (retval) | |
1239 | goto out; | |
1240 | ||
1241 | /* | |
1242 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1243 | * not visibile until then. This also enables the update | |
1244 | * to be lockless. | |
1245 | */ | |
1246 | set_mm_exe_file(bprm->mm, bprm->file); | |
1247 | ||
1248 | /* | |
1249 | * Release all of the old mmap stuff | |
1250 | */ | |
1251 | acct_arg_size(bprm, 0); | |
1252 | retval = exec_mmap(bprm->mm); | |
1253 | if (retval) | |
1254 | goto out; | |
1255 | ||
1256 | bprm->mm = NULL; /* We're using it now */ | |
1257 | ||
1258 | set_fs(USER_DS); | |
1259 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | | |
1260 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
1261 | flush_thread(); | |
1262 | current->personality &= ~bprm->per_clear; | |
1263 | ||
1264 | return 0; | |
1265 | ||
1266 | out: | |
1267 | return retval; | |
1268 | } | |
1269 | EXPORT_SYMBOL(flush_old_exec); | |
1270 | ||
1271 | void would_dump(struct linux_binprm *bprm, struct file *file) | |
1272 | { | |
1273 | if (inode_permission(file_inode(file), MAY_READ) < 0) | |
1274 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; | |
1275 | } | |
1276 | EXPORT_SYMBOL(would_dump); | |
1277 | ||
1278 | void setup_new_exec(struct linux_binprm * bprm) | |
1279 | { | |
1280 | arch_pick_mmap_layout(current->mm); | |
1281 | ||
1282 | /* This is the point of no return */ | |
1283 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1284 | ||
1285 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) | |
1286 | set_dumpable(current->mm, SUID_DUMP_USER); | |
1287 | else | |
1288 | set_dumpable(current->mm, suid_dumpable); | |
1289 | ||
1290 | perf_event_exec(); | |
1291 | __set_task_comm(current, kbasename(bprm->filename), true); | |
1292 | ||
1293 | /* Set the new mm task size. We have to do that late because it may | |
1294 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1295 | * some architectures like powerpc | |
1296 | */ | |
1297 | current->mm->task_size = TASK_SIZE; | |
1298 | ||
1299 | /* install the new credentials */ | |
1300 | if (!uid_eq(bprm->cred->uid, current_euid()) || | |
1301 | !gid_eq(bprm->cred->gid, current_egid())) { | |
1302 | current->pdeath_signal = 0; | |
1303 | } else { | |
1304 | would_dump(bprm, bprm->file); | |
1305 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) | |
1306 | set_dumpable(current->mm, suid_dumpable); | |
1307 | } | |
1308 | ||
1309 | /* An exec changes our domain. We are no longer part of the thread | |
1310 | group */ | |
1311 | current->self_exec_id++; | |
1312 | flush_signal_handlers(current, 0); | |
1313 | do_close_on_exec(current->files); | |
1314 | } | |
1315 | EXPORT_SYMBOL(setup_new_exec); | |
1316 | ||
1317 | /* | |
1318 | * Prepare credentials and lock ->cred_guard_mutex. | |
1319 | * install_exec_creds() commits the new creds and drops the lock. | |
1320 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1321 | * and unlock. | |
1322 | */ | |
1323 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1324 | { | |
1325 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) | |
1326 | return -ERESTARTNOINTR; | |
1327 | ||
1328 | bprm->cred = prepare_exec_creds(); | |
1329 | if (likely(bprm->cred)) | |
1330 | return 0; | |
1331 | ||
1332 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1333 | return -ENOMEM; | |
1334 | } | |
1335 | ||
1336 | static void free_bprm(struct linux_binprm *bprm) | |
1337 | { | |
1338 | free_arg_pages(bprm); | |
1339 | if (bprm->cred) { | |
1340 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1341 | abort_creds(bprm->cred); | |
1342 | } | |
1343 | if (bprm->file) { | |
1344 | allow_write_access(bprm->file); | |
1345 | fput(bprm->file); | |
1346 | } | |
1347 | /* If a binfmt changed the interp, free it. */ | |
1348 | if (bprm->interp != bprm->filename) | |
1349 | kfree(bprm->interp); | |
1350 | kfree(bprm); | |
1351 | } | |
1352 | ||
1353 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) | |
1354 | { | |
1355 | /* If a binfmt changed the interp, free it first. */ | |
1356 | if (bprm->interp != bprm->filename) | |
1357 | kfree(bprm->interp); | |
1358 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1359 | if (!bprm->interp) | |
1360 | return -ENOMEM; | |
1361 | return 0; | |
1362 | } | |
1363 | EXPORT_SYMBOL(bprm_change_interp); | |
1364 | ||
1365 | /* | |
1366 | * install the new credentials for this executable | |
1367 | */ | |
1368 | void install_exec_creds(struct linux_binprm *bprm) | |
1369 | { | |
1370 | security_bprm_committing_creds(bprm); | |
1371 | ||
1372 | commit_creds(bprm->cred); | |
1373 | bprm->cred = NULL; | |
1374 | ||
1375 | /* | |
1376 | * Disable monitoring for regular users | |
1377 | * when executing setuid binaries. Must | |
1378 | * wait until new credentials are committed | |
1379 | * by commit_creds() above | |
1380 | */ | |
1381 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1382 | perf_event_exit_task(current); | |
1383 | /* | |
1384 | * cred_guard_mutex must be held at least to this point to prevent | |
1385 | * ptrace_attach() from altering our determination of the task's | |
1386 | * credentials; any time after this it may be unlocked. | |
1387 | */ | |
1388 | security_bprm_committed_creds(bprm); | |
1389 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1390 | } | |
1391 | EXPORT_SYMBOL(install_exec_creds); | |
1392 | ||
1393 | /* | |
1394 | * determine how safe it is to execute the proposed program | |
1395 | * - the caller must hold ->cred_guard_mutex to protect against | |
1396 | * PTRACE_ATTACH or seccomp thread-sync | |
1397 | */ | |
1398 | static void check_unsafe_exec(struct linux_binprm *bprm) | |
1399 | { | |
1400 | struct task_struct *p = current, *t; | |
1401 | unsigned n_fs; | |
1402 | ||
1403 | if (p->ptrace) { | |
1404 | if (p->ptrace & PT_PTRACE_CAP) | |
1405 | bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1406 | else | |
1407 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
1408 | } | |
1409 | ||
1410 | /* | |
1411 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1412 | * mess up. | |
1413 | */ | |
1414 | if (task_no_new_privs(current)) | |
1415 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; | |
1416 | ||
1417 | t = p; | |
1418 | n_fs = 1; | |
1419 | spin_lock(&p->fs->lock); | |
1420 | rcu_read_lock(); | |
1421 | while_each_thread(p, t) { | |
1422 | if (t->fs == p->fs) | |
1423 | n_fs++; | |
1424 | } | |
1425 | rcu_read_unlock(); | |
1426 | ||
1427 | if (p->fs->users > n_fs) | |
1428 | bprm->unsafe |= LSM_UNSAFE_SHARE; | |
1429 | else | |
1430 | p->fs->in_exec = 1; | |
1431 | spin_unlock(&p->fs->lock); | |
1432 | } | |
1433 | ||
1434 | static void bprm_fill_uid(struct linux_binprm *bprm) | |
1435 | { | |
1436 | struct inode *inode; | |
1437 | unsigned int mode; | |
1438 | kuid_t uid; | |
1439 | kgid_t gid; | |
1440 | ||
1441 | /* | |
1442 | * Since this can be called multiple times (via prepare_binprm), | |
1443 | * we must clear any previous work done when setting set[ug]id | |
1444 | * bits from any earlier bprm->file uses (for example when run | |
1445 | * first for a setuid script then again for its interpreter). | |
1446 | */ | |
1447 | bprm->cred->euid = current_euid(); | |
1448 | bprm->cred->egid = current_egid(); | |
1449 | ||
1450 | if (!mnt_may_suid(bprm->file->f_path.mnt)) | |
1451 | return; | |
1452 | ||
1453 | if (task_no_new_privs(current)) | |
1454 | return; | |
1455 | ||
1456 | inode = file_inode(bprm->file); | |
1457 | mode = READ_ONCE(inode->i_mode); | |
1458 | if (!(mode & (S_ISUID|S_ISGID))) | |
1459 | return; | |
1460 | ||
1461 | /* Be careful if suid/sgid is set */ | |
1462 | inode_lock(inode); | |
1463 | ||
1464 | /* reload atomically mode/uid/gid now that lock held */ | |
1465 | mode = inode->i_mode; | |
1466 | uid = inode->i_uid; | |
1467 | gid = inode->i_gid; | |
1468 | inode_unlock(inode); | |
1469 | ||
1470 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1471 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1472 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1473 | return; | |
1474 | ||
1475 | if (mode & S_ISUID) { | |
1476 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1477 | bprm->cred->euid = uid; | |
1478 | } | |
1479 | ||
1480 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1481 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1482 | bprm->cred->egid = gid; | |
1483 | } | |
1484 | } | |
1485 | ||
1486 | /* | |
1487 | * Fill the binprm structure from the inode. | |
1488 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1489 | * | |
1490 | * This may be called multiple times for binary chains (scripts for example). | |
1491 | */ | |
1492 | int prepare_binprm(struct linux_binprm *bprm) | |
1493 | { | |
1494 | int retval; | |
1495 | ||
1496 | bprm_fill_uid(bprm); | |
1497 | ||
1498 | /* fill in binprm security blob */ | |
1499 | retval = security_bprm_set_creds(bprm); | |
1500 | if (retval) | |
1501 | return retval; | |
1502 | bprm->cred_prepared = 1; | |
1503 | ||
1504 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
1505 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1506 | } | |
1507 | ||
1508 | EXPORT_SYMBOL(prepare_binprm); | |
1509 | ||
1510 | /* | |
1511 | * Arguments are '\0' separated strings found at the location bprm->p | |
1512 | * points to; chop off the first by relocating brpm->p to right after | |
1513 | * the first '\0' encountered. | |
1514 | */ | |
1515 | int remove_arg_zero(struct linux_binprm *bprm) | |
1516 | { | |
1517 | int ret = 0; | |
1518 | unsigned long offset; | |
1519 | char *kaddr; | |
1520 | struct page *page; | |
1521 | ||
1522 | if (!bprm->argc) | |
1523 | return 0; | |
1524 | ||
1525 | do { | |
1526 | offset = bprm->p & ~PAGE_MASK; | |
1527 | page = get_arg_page(bprm, bprm->p, 0); | |
1528 | if (!page) { | |
1529 | ret = -EFAULT; | |
1530 | goto out; | |
1531 | } | |
1532 | kaddr = kmap_atomic(page); | |
1533 | ||
1534 | for (; offset < PAGE_SIZE && kaddr[offset]; | |
1535 | offset++, bprm->p++) | |
1536 | ; | |
1537 | ||
1538 | kunmap_atomic(kaddr); | |
1539 | put_arg_page(page); | |
1540 | } while (offset == PAGE_SIZE); | |
1541 | ||
1542 | bprm->p++; | |
1543 | bprm->argc--; | |
1544 | ret = 0; | |
1545 | ||
1546 | out: | |
1547 | return ret; | |
1548 | } | |
1549 | EXPORT_SYMBOL(remove_arg_zero); | |
1550 | ||
1551 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1552 | /* | |
1553 | * cycle the list of binary formats handler, until one recognizes the image | |
1554 | */ | |
1555 | int search_binary_handler(struct linux_binprm *bprm) | |
1556 | { | |
1557 | bool need_retry = IS_ENABLED(CONFIG_MODULES); | |
1558 | struct linux_binfmt *fmt; | |
1559 | int retval; | |
1560 | ||
1561 | /* This allows 4 levels of binfmt rewrites before failing hard. */ | |
1562 | if (bprm->recursion_depth > 5) | |
1563 | return -ELOOP; | |
1564 | ||
1565 | retval = security_bprm_check(bprm); | |
1566 | if (retval) | |
1567 | return retval; | |
1568 | ||
1569 | retval = -ENOENT; | |
1570 | retry: | |
1571 | read_lock(&binfmt_lock); | |
1572 | list_for_each_entry(fmt, &formats, lh) { | |
1573 | if (!try_module_get(fmt->module)) | |
1574 | continue; | |
1575 | read_unlock(&binfmt_lock); | |
1576 | bprm->recursion_depth++; | |
1577 | retval = fmt->load_binary(bprm); | |
1578 | read_lock(&binfmt_lock); | |
1579 | put_binfmt(fmt); | |
1580 | bprm->recursion_depth--; | |
1581 | if (retval < 0 && !bprm->mm) { | |
1582 | /* we got to flush_old_exec() and failed after it */ | |
1583 | read_unlock(&binfmt_lock); | |
1584 | force_sigsegv(SIGSEGV, current); | |
1585 | return retval; | |
1586 | } | |
1587 | if (retval != -ENOEXEC || !bprm->file) { | |
1588 | read_unlock(&binfmt_lock); | |
1589 | return retval; | |
1590 | } | |
1591 | } | |
1592 | read_unlock(&binfmt_lock); | |
1593 | ||
1594 | if (need_retry) { | |
1595 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && | |
1596 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1597 | return retval; | |
1598 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) | |
1599 | return retval; | |
1600 | need_retry = false; | |
1601 | goto retry; | |
1602 | } | |
1603 | ||
1604 | return retval; | |
1605 | } | |
1606 | EXPORT_SYMBOL(search_binary_handler); | |
1607 | ||
1608 | static int exec_binprm(struct linux_binprm *bprm) | |
1609 | { | |
1610 | pid_t old_pid, old_vpid; | |
1611 | int ret; | |
1612 | ||
1613 | /* Need to fetch pid before load_binary changes it */ | |
1614 | old_pid = current->pid; | |
1615 | rcu_read_lock(); | |
1616 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1617 | rcu_read_unlock(); | |
1618 | ||
1619 | ret = search_binary_handler(bprm); | |
1620 | if (ret >= 0) { | |
1621 | audit_bprm(bprm); | |
1622 | trace_sched_process_exec(current, old_pid, bprm); | |
1623 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
1624 | proc_exec_connector(current); | |
1625 | } | |
1626 | ||
1627 | return ret; | |
1628 | } | |
1629 | ||
1630 | /* | |
1631 | * sys_execve() executes a new program. | |
1632 | */ | |
1633 | static int do_execveat_common(int fd, struct filename *filename, | |
1634 | struct user_arg_ptr argv, | |
1635 | struct user_arg_ptr envp, | |
1636 | int flags) | |
1637 | { | |
1638 | char *pathbuf = NULL; | |
1639 | struct linux_binprm *bprm; | |
1640 | struct file *file; | |
1641 | struct files_struct *displaced; | |
1642 | int retval; | |
1643 | ||
1644 | if (IS_ERR(filename)) | |
1645 | return PTR_ERR(filename); | |
1646 | ||
1647 | /* | |
1648 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1649 | * set*uid() to execve() because too many poorly written programs | |
1650 | * don't check setuid() return code. Here we additionally recheck | |
1651 | * whether NPROC limit is still exceeded. | |
1652 | */ | |
1653 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
1654 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { | |
1655 | retval = -EAGAIN; | |
1656 | goto out_ret; | |
1657 | } | |
1658 | ||
1659 | /* We're below the limit (still or again), so we don't want to make | |
1660 | * further execve() calls fail. */ | |
1661 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1662 | ||
1663 | retval = unshare_files(&displaced); | |
1664 | if (retval) | |
1665 | goto out_ret; | |
1666 | ||
1667 | retval = -ENOMEM; | |
1668 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); | |
1669 | if (!bprm) | |
1670 | goto out_files; | |
1671 | ||
1672 | retval = prepare_bprm_creds(bprm); | |
1673 | if (retval) | |
1674 | goto out_free; | |
1675 | ||
1676 | check_unsafe_exec(bprm); | |
1677 | current->in_execve = 1; | |
1678 | ||
1679 | file = do_open_execat(fd, filename, flags); | |
1680 | retval = PTR_ERR(file); | |
1681 | if (IS_ERR(file)) | |
1682 | goto out_unmark; | |
1683 | ||
1684 | sched_exec(); | |
1685 | ||
1686 | bprm->file = file; | |
1687 | if (fd == AT_FDCWD || filename->name[0] == '/') { | |
1688 | bprm->filename = filename->name; | |
1689 | } else { | |
1690 | if (filename->name[0] == '\0') | |
1691 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1692 | else | |
1693 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1694 | fd, filename->name); | |
1695 | if (!pathbuf) { | |
1696 | retval = -ENOMEM; | |
1697 | goto out_unmark; | |
1698 | } | |
1699 | /* | |
1700 | * Record that a name derived from an O_CLOEXEC fd will be | |
1701 | * inaccessible after exec. Relies on having exclusive access to | |
1702 | * current->files (due to unshare_files above). | |
1703 | */ | |
1704 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1705 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1706 | bprm->filename = pathbuf; | |
1707 | } | |
1708 | bprm->interp = bprm->filename; | |
1709 | ||
1710 | retval = bprm_mm_init(bprm); | |
1711 | if (retval) | |
1712 | goto out_unmark; | |
1713 | ||
1714 | bprm->argc = count(argv, MAX_ARG_STRINGS); | |
1715 | if ((retval = bprm->argc) < 0) | |
1716 | goto out; | |
1717 | ||
1718 | bprm->envc = count(envp, MAX_ARG_STRINGS); | |
1719 | if ((retval = bprm->envc) < 0) | |
1720 | goto out; | |
1721 | ||
1722 | retval = prepare_binprm(bprm); | |
1723 | if (retval < 0) | |
1724 | goto out; | |
1725 | ||
1726 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1727 | if (retval < 0) | |
1728 | goto out; | |
1729 | ||
1730 | bprm->exec = bprm->p; | |
1731 | retval = copy_strings(bprm->envc, envp, bprm); | |
1732 | if (retval < 0) | |
1733 | goto out; | |
1734 | ||
1735 | retval = copy_strings(bprm->argc, argv, bprm); | |
1736 | if (retval < 0) | |
1737 | goto out; | |
1738 | ||
1739 | retval = exec_binprm(bprm); | |
1740 | if (retval < 0) | |
1741 | goto out; | |
1742 | ||
1743 | /* execve succeeded */ | |
1744 | current->fs->in_exec = 0; | |
1745 | current->in_execve = 0; | |
1746 | acct_update_integrals(current); | |
1747 | task_numa_free(current); | |
1748 | free_bprm(bprm); | |
1749 | kfree(pathbuf); | |
1750 | putname(filename); | |
1751 | if (displaced) | |
1752 | put_files_struct(displaced); | |
1753 | return retval; | |
1754 | ||
1755 | out: | |
1756 | if (bprm->mm) { | |
1757 | acct_arg_size(bprm, 0); | |
1758 | mmput(bprm->mm); | |
1759 | } | |
1760 | ||
1761 | out_unmark: | |
1762 | current->fs->in_exec = 0; | |
1763 | current->in_execve = 0; | |
1764 | ||
1765 | out_free: | |
1766 | free_bprm(bprm); | |
1767 | kfree(pathbuf); | |
1768 | ||
1769 | out_files: | |
1770 | if (displaced) | |
1771 | reset_files_struct(displaced); | |
1772 | out_ret: | |
1773 | putname(filename); | |
1774 | return retval; | |
1775 | } | |
1776 | ||
1777 | int do_execve(struct filename *filename, | |
1778 | const char __user *const __user *__argv, | |
1779 | const char __user *const __user *__envp) | |
1780 | { | |
1781 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1782 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1783 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1784 | } | |
1785 | ||
1786 | int do_execveat(int fd, struct filename *filename, | |
1787 | const char __user *const __user *__argv, | |
1788 | const char __user *const __user *__envp, | |
1789 | int flags) | |
1790 | { | |
1791 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1792 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1793 | ||
1794 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1795 | } | |
1796 | ||
1797 | #ifdef CONFIG_COMPAT | |
1798 | static int compat_do_execve(struct filename *filename, | |
1799 | const compat_uptr_t __user *__argv, | |
1800 | const compat_uptr_t __user *__envp) | |
1801 | { | |
1802 | struct user_arg_ptr argv = { | |
1803 | .is_compat = true, | |
1804 | .ptr.compat = __argv, | |
1805 | }; | |
1806 | struct user_arg_ptr envp = { | |
1807 | .is_compat = true, | |
1808 | .ptr.compat = __envp, | |
1809 | }; | |
1810 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1811 | } | |
1812 | ||
1813 | static int compat_do_execveat(int fd, struct filename *filename, | |
1814 | const compat_uptr_t __user *__argv, | |
1815 | const compat_uptr_t __user *__envp, | |
1816 | int flags) | |
1817 | { | |
1818 | struct user_arg_ptr argv = { | |
1819 | .is_compat = true, | |
1820 | .ptr.compat = __argv, | |
1821 | }; | |
1822 | struct user_arg_ptr envp = { | |
1823 | .is_compat = true, | |
1824 | .ptr.compat = __envp, | |
1825 | }; | |
1826 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1827 | } | |
1828 | #endif | |
1829 | ||
1830 | void set_binfmt(struct linux_binfmt *new) | |
1831 | { | |
1832 | struct mm_struct *mm = current->mm; | |
1833 | ||
1834 | if (mm->binfmt) | |
1835 | module_put(mm->binfmt->module); | |
1836 | ||
1837 | mm->binfmt = new; | |
1838 | if (new) | |
1839 | __module_get(new->module); | |
1840 | } | |
1841 | EXPORT_SYMBOL(set_binfmt); | |
1842 | ||
1843 | /* | |
1844 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. | |
1845 | */ | |
1846 | void set_dumpable(struct mm_struct *mm, int value) | |
1847 | { | |
1848 | unsigned long old, new; | |
1849 | ||
1850 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) | |
1851 | return; | |
1852 | ||
1853 | do { | |
1854 | old = ACCESS_ONCE(mm->flags); | |
1855 | new = (old & ~MMF_DUMPABLE_MASK) | value; | |
1856 | } while (cmpxchg(&mm->flags, old, new) != old); | |
1857 | } | |
1858 | ||
1859 | SYSCALL_DEFINE3(execve, | |
1860 | const char __user *, filename, | |
1861 | const char __user *const __user *, argv, | |
1862 | const char __user *const __user *, envp) | |
1863 | { | |
1864 | return do_execve(getname(filename), argv, envp); | |
1865 | } | |
1866 | ||
1867 | SYSCALL_DEFINE5(execveat, | |
1868 | int, fd, const char __user *, filename, | |
1869 | const char __user *const __user *, argv, | |
1870 | const char __user *const __user *, envp, | |
1871 | int, flags) | |
1872 | { | |
1873 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1874 | ||
1875 | return do_execveat(fd, | |
1876 | getname_flags(filename, lookup_flags, NULL), | |
1877 | argv, envp, flags); | |
1878 | } | |
1879 | ||
1880 | #ifdef CONFIG_COMPAT | |
1881 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, | |
1882 | const compat_uptr_t __user *, argv, | |
1883 | const compat_uptr_t __user *, envp) | |
1884 | { | |
1885 | return compat_do_execve(getname(filename), argv, envp); | |
1886 | } | |
1887 | ||
1888 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1889 | const char __user *, filename, | |
1890 | const compat_uptr_t __user *, argv, | |
1891 | const compat_uptr_t __user *, envp, | |
1892 | int, flags) | |
1893 | { | |
1894 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1895 | ||
1896 | return compat_do_execveat(fd, | |
1897 | getname_flags(filename, lookup_flags, NULL), | |
1898 | argv, envp, flags); | |
1899 | } | |
1900 | #endif |