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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 <linux/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 | unsigned int gup_flags = FOLL_FORCE; | |
195 | ||
196 | #ifdef CONFIG_STACK_GROWSUP | |
197 | if (write) { | |
198 | ret = expand_downwards(bprm->vma, pos); | |
199 | if (ret < 0) | |
200 | return NULL; | |
201 | } | |
202 | #endif | |
203 | ||
204 | if (write) | |
205 | gup_flags |= FOLL_WRITE; | |
206 | ||
207 | /* | |
208 | * We are doing an exec(). 'current' is the process | |
209 | * doing the exec and bprm->mm is the new process's mm. | |
210 | */ | |
211 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, | |
212 | &page, NULL, NULL); | |
213 | if (ret <= 0) | |
214 | return NULL; | |
215 | ||
216 | if (write) { | |
217 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
218 | struct rlimit *rlim; | |
219 | ||
220 | acct_arg_size(bprm, size / PAGE_SIZE); | |
221 | ||
222 | /* | |
223 | * We've historically supported up to 32 pages (ARG_MAX) | |
224 | * of argument strings even with small stacks | |
225 | */ | |
226 | if (size <= ARG_MAX) | |
227 | return page; | |
228 | ||
229 | /* | |
230 | * Limit to 1/4-th the stack size for the argv+env strings. | |
231 | * This ensures that: | |
232 | * - the remaining binfmt code will not run out of stack space, | |
233 | * - the program will have a reasonable amount of stack left | |
234 | * to work from. | |
235 | */ | |
236 | rlim = current->signal->rlim; | |
237 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { | |
238 | put_page(page); | |
239 | return NULL; | |
240 | } | |
241 | } | |
242 | ||
243 | return page; | |
244 | } | |
245 | ||
246 | static void put_arg_page(struct page *page) | |
247 | { | |
248 | put_page(page); | |
249 | } | |
250 | ||
251 | static void free_arg_pages(struct linux_binprm *bprm) | |
252 | { | |
253 | } | |
254 | ||
255 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
256 | struct page *page) | |
257 | { | |
258 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
259 | } | |
260 | ||
261 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
262 | { | |
263 | int err; | |
264 | struct vm_area_struct *vma = NULL; | |
265 | struct mm_struct *mm = bprm->mm; | |
266 | ||
267 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
268 | if (!vma) | |
269 | return -ENOMEM; | |
270 | ||
271 | if (down_write_killable(&mm->mmap_sem)) { | |
272 | err = -EINTR; | |
273 | goto err_free; | |
274 | } | |
275 | vma->vm_mm = mm; | |
276 | ||
277 | /* | |
278 | * Place the stack at the largest stack address the architecture | |
279 | * supports. Later, we'll move this to an appropriate place. We don't | |
280 | * use STACK_TOP because that can depend on attributes which aren't | |
281 | * configured yet. | |
282 | */ | |
283 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); | |
284 | vma->vm_end = STACK_TOP_MAX; | |
285 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
286 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; | |
287 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); | |
288 | INIT_LIST_HEAD(&vma->anon_vma_chain); | |
289 | ||
290 | err = insert_vm_struct(mm, vma); | |
291 | if (err) | |
292 | goto err; | |
293 | ||
294 | mm->stack_vm = mm->total_vm = 1; | |
295 | arch_bprm_mm_init(mm, vma); | |
296 | up_write(&mm->mmap_sem); | |
297 | bprm->p = vma->vm_end - sizeof(void *); | |
298 | return 0; | |
299 | err: | |
300 | up_write(&mm->mmap_sem); | |
301 | err_free: | |
302 | bprm->vma = NULL; | |
303 | kmem_cache_free(vm_area_cachep, vma); | |
304 | return err; | |
305 | } | |
306 | ||
307 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
308 | { | |
309 | return len <= MAX_ARG_STRLEN; | |
310 | } | |
311 | ||
312 | #else | |
313 | ||
314 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) | |
315 | { | |
316 | } | |
317 | ||
318 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
319 | int write) | |
320 | { | |
321 | struct page *page; | |
322 | ||
323 | page = bprm->page[pos / PAGE_SIZE]; | |
324 | if (!page && write) { | |
325 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
326 | if (!page) | |
327 | return NULL; | |
328 | bprm->page[pos / PAGE_SIZE] = page; | |
329 | } | |
330 | ||
331 | return page; | |
332 | } | |
333 | ||
334 | static void put_arg_page(struct page *page) | |
335 | { | |
336 | } | |
337 | ||
338 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
339 | { | |
340 | if (bprm->page[i]) { | |
341 | __free_page(bprm->page[i]); | |
342 | bprm->page[i] = NULL; | |
343 | } | |
344 | } | |
345 | ||
346 | static void free_arg_pages(struct linux_binprm *bprm) | |
347 | { | |
348 | int i; | |
349 | ||
350 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
351 | free_arg_page(bprm, i); | |
352 | } | |
353 | ||
354 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
355 | struct page *page) | |
356 | { | |
357 | } | |
358 | ||
359 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
360 | { | |
361 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
362 | return 0; | |
363 | } | |
364 | ||
365 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
366 | { | |
367 | return len <= bprm->p; | |
368 | } | |
369 | ||
370 | #endif /* CONFIG_MMU */ | |
371 | ||
372 | /* | |
373 | * Create a new mm_struct and populate it with a temporary stack | |
374 | * vm_area_struct. We don't have enough context at this point to set the stack | |
375 | * flags, permissions, and offset, so we use temporary values. We'll update | |
376 | * them later in setup_arg_pages(). | |
377 | */ | |
378 | static int bprm_mm_init(struct linux_binprm *bprm) | |
379 | { | |
380 | int err; | |
381 | struct mm_struct *mm = NULL; | |
382 | ||
383 | bprm->mm = mm = mm_alloc(); | |
384 | err = -ENOMEM; | |
385 | if (!mm) | |
386 | goto err; | |
387 | ||
388 | err = __bprm_mm_init(bprm); | |
389 | if (err) | |
390 | goto err; | |
391 | ||
392 | return 0; | |
393 | ||
394 | err: | |
395 | if (mm) { | |
396 | bprm->mm = NULL; | |
397 | mmdrop(mm); | |
398 | } | |
399 | ||
400 | return err; | |
401 | } | |
402 | ||
403 | struct user_arg_ptr { | |
404 | #ifdef CONFIG_COMPAT | |
405 | bool is_compat; | |
406 | #endif | |
407 | union { | |
408 | const char __user *const __user *native; | |
409 | #ifdef CONFIG_COMPAT | |
410 | const compat_uptr_t __user *compat; | |
411 | #endif | |
412 | } ptr; | |
413 | }; | |
414 | ||
415 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
416 | { | |
417 | const char __user *native; | |
418 | ||
419 | #ifdef CONFIG_COMPAT | |
420 | if (unlikely(argv.is_compat)) { | |
421 | compat_uptr_t compat; | |
422 | ||
423 | if (get_user(compat, argv.ptr.compat + nr)) | |
424 | return ERR_PTR(-EFAULT); | |
425 | ||
426 | return compat_ptr(compat); | |
427 | } | |
428 | #endif | |
429 | ||
430 | if (get_user(native, argv.ptr.native + nr)) | |
431 | return ERR_PTR(-EFAULT); | |
432 | ||
433 | return native; | |
434 | } | |
435 | ||
436 | /* | |
437 | * count() counts the number of strings in array ARGV. | |
438 | */ | |
439 | static int count(struct user_arg_ptr argv, int max) | |
440 | { | |
441 | int i = 0; | |
442 | ||
443 | if (argv.ptr.native != NULL) { | |
444 | for (;;) { | |
445 | const char __user *p = get_user_arg_ptr(argv, i); | |
446 | ||
447 | if (!p) | |
448 | break; | |
449 | ||
450 | if (IS_ERR(p)) | |
451 | return -EFAULT; | |
452 | ||
453 | if (i >= max) | |
454 | return -E2BIG; | |
455 | ++i; | |
456 | ||
457 | if (fatal_signal_pending(current)) | |
458 | return -ERESTARTNOHAND; | |
459 | cond_resched(); | |
460 | } | |
461 | } | |
462 | return i; | |
463 | } | |
464 | ||
465 | /* | |
466 | * 'copy_strings()' copies argument/environment strings from the old | |
467 | * processes's memory to the new process's stack. The call to get_user_pages() | |
468 | * ensures the destination page is created and not swapped out. | |
469 | */ | |
470 | static int copy_strings(int argc, struct user_arg_ptr argv, | |
471 | struct linux_binprm *bprm) | |
472 | { | |
473 | struct page *kmapped_page = NULL; | |
474 | char *kaddr = NULL; | |
475 | unsigned long kpos = 0; | |
476 | int ret; | |
477 | ||
478 | while (argc-- > 0) { | |
479 | const char __user *str; | |
480 | int len; | |
481 | unsigned long pos; | |
482 | ||
483 | ret = -EFAULT; | |
484 | str = get_user_arg_ptr(argv, argc); | |
485 | if (IS_ERR(str)) | |
486 | goto out; | |
487 | ||
488 | len = strnlen_user(str, MAX_ARG_STRLEN); | |
489 | if (!len) | |
490 | goto out; | |
491 | ||
492 | ret = -E2BIG; | |
493 | if (!valid_arg_len(bprm, len)) | |
494 | goto out; | |
495 | ||
496 | /* We're going to work our way backwords. */ | |
497 | pos = bprm->p; | |
498 | str += len; | |
499 | bprm->p -= len; | |
500 | ||
501 | while (len > 0) { | |
502 | int offset, bytes_to_copy; | |
503 | ||
504 | if (fatal_signal_pending(current)) { | |
505 | ret = -ERESTARTNOHAND; | |
506 | goto out; | |
507 | } | |
508 | cond_resched(); | |
509 | ||
510 | offset = pos % PAGE_SIZE; | |
511 | if (offset == 0) | |
512 | offset = PAGE_SIZE; | |
513 | ||
514 | bytes_to_copy = offset; | |
515 | if (bytes_to_copy > len) | |
516 | bytes_to_copy = len; | |
517 | ||
518 | offset -= bytes_to_copy; | |
519 | pos -= bytes_to_copy; | |
520 | str -= bytes_to_copy; | |
521 | len -= bytes_to_copy; | |
522 | ||
523 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
524 | struct page *page; | |
525 | ||
526 | page = get_arg_page(bprm, pos, 1); | |
527 | if (!page) { | |
528 | ret = -E2BIG; | |
529 | goto out; | |
530 | } | |
531 | ||
532 | if (kmapped_page) { | |
533 | flush_kernel_dcache_page(kmapped_page); | |
534 | kunmap(kmapped_page); | |
535 | put_arg_page(kmapped_page); | |
536 | } | |
537 | kmapped_page = page; | |
538 | kaddr = kmap(kmapped_page); | |
539 | kpos = pos & PAGE_MASK; | |
540 | flush_arg_page(bprm, kpos, kmapped_page); | |
541 | } | |
542 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { | |
543 | ret = -EFAULT; | |
544 | goto out; | |
545 | } | |
546 | } | |
547 | } | |
548 | ret = 0; | |
549 | out: | |
550 | if (kmapped_page) { | |
551 | flush_kernel_dcache_page(kmapped_page); | |
552 | kunmap(kmapped_page); | |
553 | put_arg_page(kmapped_page); | |
554 | } | |
555 | return ret; | |
556 | } | |
557 | ||
558 | /* | |
559 | * Like copy_strings, but get argv and its values from kernel memory. | |
560 | */ | |
561 | int copy_strings_kernel(int argc, const char *const *__argv, | |
562 | struct linux_binprm *bprm) | |
563 | { | |
564 | int r; | |
565 | mm_segment_t oldfs = get_fs(); | |
566 | struct user_arg_ptr argv = { | |
567 | .ptr.native = (const char __user *const __user *)__argv, | |
568 | }; | |
569 | ||
570 | set_fs(KERNEL_DS); | |
571 | r = copy_strings(argc, argv, bprm); | |
572 | set_fs(oldfs); | |
573 | ||
574 | return r; | |
575 | } | |
576 | EXPORT_SYMBOL(copy_strings_kernel); | |
577 | ||
578 | #ifdef CONFIG_MMU | |
579 | ||
580 | /* | |
581 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once | |
582 | * the binfmt code determines where the new stack should reside, we shift it to | |
583 | * its final location. The process proceeds as follows: | |
584 | * | |
585 | * 1) Use shift to calculate the new vma endpoints. | |
586 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
587 | * arguments passed to subsequent functions are consistent. | |
588 | * 3) Move vma's page tables to the new range. | |
589 | * 4) Free up any cleared pgd range. | |
590 | * 5) Shrink the vma to cover only the new range. | |
591 | */ | |
592 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) | |
593 | { | |
594 | struct mm_struct *mm = vma->vm_mm; | |
595 | unsigned long old_start = vma->vm_start; | |
596 | unsigned long old_end = vma->vm_end; | |
597 | unsigned long length = old_end - old_start; | |
598 | unsigned long new_start = old_start - shift; | |
599 | unsigned long new_end = old_end - shift; | |
600 | struct mmu_gather tlb; | |
601 | ||
602 | BUG_ON(new_start > new_end); | |
603 | ||
604 | /* | |
605 | * ensure there are no vmas between where we want to go | |
606 | * and where we are | |
607 | */ | |
608 | if (vma != find_vma(mm, new_start)) | |
609 | return -EFAULT; | |
610 | ||
611 | /* | |
612 | * cover the whole range: [new_start, old_end) | |
613 | */ | |
614 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) | |
615 | return -ENOMEM; | |
616 | ||
617 | /* | |
618 | * move the page tables downwards, on failure we rely on | |
619 | * process cleanup to remove whatever mess we made. | |
620 | */ | |
621 | if (length != move_page_tables(vma, old_start, | |
622 | vma, new_start, length, false)) | |
623 | return -ENOMEM; | |
624 | ||
625 | lru_add_drain(); | |
626 | tlb_gather_mmu(&tlb, mm, old_start, old_end); | |
627 | if (new_end > old_start) { | |
628 | /* | |
629 | * when the old and new regions overlap clear from new_end. | |
630 | */ | |
631 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
632 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
633 | } else { | |
634 | /* | |
635 | * otherwise, clean from old_start; this is done to not touch | |
636 | * the address space in [new_end, old_start) some architectures | |
637 | * have constraints on va-space that make this illegal (IA64) - | |
638 | * for the others its just a little faster. | |
639 | */ | |
640 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
641 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
642 | } | |
643 | tlb_finish_mmu(&tlb, old_start, old_end); | |
644 | ||
645 | /* | |
646 | * Shrink the vma to just the new range. Always succeeds. | |
647 | */ | |
648 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
649 | ||
650 | return 0; | |
651 | } | |
652 | ||
653 | /* | |
654 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
655 | * the stack is optionally relocated, and some extra space is added. | |
656 | */ | |
657 | int setup_arg_pages(struct linux_binprm *bprm, | |
658 | unsigned long stack_top, | |
659 | int executable_stack) | |
660 | { | |
661 | unsigned long ret; | |
662 | unsigned long stack_shift; | |
663 | struct mm_struct *mm = current->mm; | |
664 | struct vm_area_struct *vma = bprm->vma; | |
665 | struct vm_area_struct *prev = NULL; | |
666 | unsigned long vm_flags; | |
667 | unsigned long stack_base; | |
668 | unsigned long stack_size; | |
669 | unsigned long stack_expand; | |
670 | unsigned long rlim_stack; | |
671 | ||
672 | #ifdef CONFIG_STACK_GROWSUP | |
673 | /* Limit stack size */ | |
674 | stack_base = rlimit_max(RLIMIT_STACK); | |
675 | if (stack_base > STACK_SIZE_MAX) | |
676 | stack_base = STACK_SIZE_MAX; | |
677 | ||
678 | /* Add space for stack randomization. */ | |
679 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
680 | ||
681 | /* Make sure we didn't let the argument array grow too large. */ | |
682 | if (vma->vm_end - vma->vm_start > stack_base) | |
683 | return -ENOMEM; | |
684 | ||
685 | stack_base = PAGE_ALIGN(stack_top - stack_base); | |
686 | ||
687 | stack_shift = vma->vm_start - stack_base; | |
688 | mm->arg_start = bprm->p - stack_shift; | |
689 | bprm->p = vma->vm_end - stack_shift; | |
690 | #else | |
691 | stack_top = arch_align_stack(stack_top); | |
692 | stack_top = PAGE_ALIGN(stack_top); | |
693 | ||
694 | if (unlikely(stack_top < mmap_min_addr) || | |
695 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
696 | return -ENOMEM; | |
697 | ||
698 | stack_shift = vma->vm_end - stack_top; | |
699 | ||
700 | bprm->p -= stack_shift; | |
701 | mm->arg_start = bprm->p; | |
702 | #endif | |
703 | ||
704 | if (bprm->loader) | |
705 | bprm->loader -= stack_shift; | |
706 | bprm->exec -= stack_shift; | |
707 | ||
708 | if (down_write_killable(&mm->mmap_sem)) | |
709 | return -EINTR; | |
710 | ||
711 | vm_flags = VM_STACK_FLAGS; | |
712 | ||
713 | /* | |
714 | * Adjust stack execute permissions; explicitly enable for | |
715 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
716 | * (arch default) otherwise. | |
717 | */ | |
718 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
719 | vm_flags |= VM_EXEC; | |
720 | else if (executable_stack == EXSTACK_DISABLE_X) | |
721 | vm_flags &= ~VM_EXEC; | |
722 | vm_flags |= mm->def_flags; | |
723 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; | |
724 | ||
725 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
726 | vm_flags); | |
727 | if (ret) | |
728 | goto out_unlock; | |
729 | BUG_ON(prev != vma); | |
730 | ||
731 | /* Move stack pages down in memory. */ | |
732 | if (stack_shift) { | |
733 | ret = shift_arg_pages(vma, stack_shift); | |
734 | if (ret) | |
735 | goto out_unlock; | |
736 | } | |
737 | ||
738 | /* mprotect_fixup is overkill to remove the temporary stack flags */ | |
739 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
740 | ||
741 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ | |
742 | stack_size = vma->vm_end - vma->vm_start; | |
743 | /* | |
744 | * Align this down to a page boundary as expand_stack | |
745 | * will align it up. | |
746 | */ | |
747 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
748 | #ifdef CONFIG_STACK_GROWSUP | |
749 | if (stack_size + stack_expand > rlim_stack) | |
750 | stack_base = vma->vm_start + rlim_stack; | |
751 | else | |
752 | stack_base = vma->vm_end + stack_expand; | |
753 | #else | |
754 | if (stack_size + stack_expand > rlim_stack) | |
755 | stack_base = vma->vm_end - rlim_stack; | |
756 | else | |
757 | stack_base = vma->vm_start - stack_expand; | |
758 | #endif | |
759 | current->mm->start_stack = bprm->p; | |
760 | ret = expand_stack(vma, stack_base); | |
761 | if (ret) | |
762 | ret = -EFAULT; | |
763 | ||
764 | out_unlock: | |
765 | up_write(&mm->mmap_sem); | |
766 | return ret; | |
767 | } | |
768 | EXPORT_SYMBOL(setup_arg_pages); | |
769 | ||
770 | #else | |
771 | ||
772 | /* | |
773 | * Transfer the program arguments and environment from the holding pages | |
774 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
775 | */ | |
776 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
777 | unsigned long *sp_location) | |
778 | { | |
779 | unsigned long index, stop, sp; | |
780 | int ret = 0; | |
781 | ||
782 | stop = bprm->p >> PAGE_SHIFT; | |
783 | sp = *sp_location; | |
784 | ||
785 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
786 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
787 | char *src = kmap(bprm->page[index]) + offset; | |
788 | sp -= PAGE_SIZE - offset; | |
789 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
790 | ret = -EFAULT; | |
791 | kunmap(bprm->page[index]); | |
792 | if (ret) | |
793 | goto out; | |
794 | } | |
795 | ||
796 | *sp_location = sp; | |
797 | ||
798 | out: | |
799 | return ret; | |
800 | } | |
801 | EXPORT_SYMBOL(transfer_args_to_stack); | |
802 | ||
803 | #endif /* CONFIG_MMU */ | |
804 | ||
805 | static struct file *do_open_execat(int fd, struct filename *name, int flags) | |
806 | { | |
807 | struct file *file; | |
808 | int err; | |
809 | struct open_flags open_exec_flags = { | |
810 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
811 | .acc_mode = MAY_EXEC, | |
812 | .intent = LOOKUP_OPEN, | |
813 | .lookup_flags = LOOKUP_FOLLOW, | |
814 | }; | |
815 | ||
816 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) | |
817 | return ERR_PTR(-EINVAL); | |
818 | if (flags & AT_SYMLINK_NOFOLLOW) | |
819 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
820 | if (flags & AT_EMPTY_PATH) | |
821 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
822 | ||
823 | file = do_filp_open(fd, name, &open_exec_flags); | |
824 | if (IS_ERR(file)) | |
825 | goto out; | |
826 | ||
827 | err = -EACCES; | |
828 | if (!S_ISREG(file_inode(file)->i_mode)) | |
829 | goto exit; | |
830 | ||
831 | if (path_noexec(&file->f_path)) | |
832 | goto exit; | |
833 | ||
834 | err = deny_write_access(file); | |
835 | if (err) | |
836 | goto exit; | |
837 | ||
838 | if (name->name[0] != '\0') | |
839 | fsnotify_open(file); | |
840 | ||
841 | out: | |
842 | return file; | |
843 | ||
844 | exit: | |
845 | fput(file); | |
846 | return ERR_PTR(err); | |
847 | } | |
848 | ||
849 | struct file *open_exec(const char *name) | |
850 | { | |
851 | struct filename *filename = getname_kernel(name); | |
852 | struct file *f = ERR_CAST(filename); | |
853 | ||
854 | if (!IS_ERR(filename)) { | |
855 | f = do_open_execat(AT_FDCWD, filename, 0); | |
856 | putname(filename); | |
857 | } | |
858 | return f; | |
859 | } | |
860 | EXPORT_SYMBOL(open_exec); | |
861 | ||
862 | int kernel_read(struct file *file, loff_t offset, | |
863 | char *addr, unsigned long count) | |
864 | { | |
865 | mm_segment_t old_fs; | |
866 | loff_t pos = offset; | |
867 | int result; | |
868 | ||
869 | old_fs = get_fs(); | |
870 | set_fs(get_ds()); | |
871 | /* The cast to a user pointer is valid due to the set_fs() */ | |
872 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
873 | set_fs(old_fs); | |
874 | return result; | |
875 | } | |
876 | ||
877 | EXPORT_SYMBOL(kernel_read); | |
878 | ||
879 | int kernel_read_file(struct file *file, void **buf, loff_t *size, | |
880 | loff_t max_size, enum kernel_read_file_id id) | |
881 | { | |
882 | loff_t i_size, pos; | |
883 | ssize_t bytes = 0; | |
884 | int ret; | |
885 | ||
886 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
887 | return -EINVAL; | |
888 | ||
889 | ret = security_kernel_read_file(file, id); | |
890 | if (ret) | |
891 | return ret; | |
892 | ||
893 | ret = deny_write_access(file); | |
894 | if (ret) | |
895 | return ret; | |
896 | ||
897 | i_size = i_size_read(file_inode(file)); | |
898 | if (max_size > 0 && i_size > max_size) { | |
899 | ret = -EFBIG; | |
900 | goto out; | |
901 | } | |
902 | if (i_size <= 0) { | |
903 | ret = -EINVAL; | |
904 | goto out; | |
905 | } | |
906 | ||
907 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) | |
908 | *buf = vmalloc(i_size); | |
909 | if (!*buf) { | |
910 | ret = -ENOMEM; | |
911 | goto out; | |
912 | } | |
913 | ||
914 | pos = 0; | |
915 | while (pos < i_size) { | |
916 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
917 | i_size - pos); | |
918 | if (bytes < 0) { | |
919 | ret = bytes; | |
920 | goto out; | |
921 | } | |
922 | ||
923 | if (bytes == 0) | |
924 | break; | |
925 | pos += bytes; | |
926 | } | |
927 | ||
928 | if (pos != i_size) { | |
929 | ret = -EIO; | |
930 | goto out_free; | |
931 | } | |
932 | ||
933 | ret = security_kernel_post_read_file(file, *buf, i_size, id); | |
934 | if (!ret) | |
935 | *size = pos; | |
936 | ||
937 | out_free: | |
938 | if (ret < 0) { | |
939 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { | |
940 | vfree(*buf); | |
941 | *buf = NULL; | |
942 | } | |
943 | } | |
944 | ||
945 | out: | |
946 | allow_write_access(file); | |
947 | return ret; | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
950 | ||
951 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, | |
952 | loff_t max_size, enum kernel_read_file_id id) | |
953 | { | |
954 | struct file *file; | |
955 | int ret; | |
956 | ||
957 | if (!path || !*path) | |
958 | return -EINVAL; | |
959 | ||
960 | file = filp_open(path, O_RDONLY, 0); | |
961 | if (IS_ERR(file)) | |
962 | return PTR_ERR(file); | |
963 | ||
964 | ret = kernel_read_file(file, buf, size, max_size, id); | |
965 | fput(file); | |
966 | return ret; | |
967 | } | |
968 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
969 | ||
970 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, | |
971 | enum kernel_read_file_id id) | |
972 | { | |
973 | struct fd f = fdget(fd); | |
974 | int ret = -EBADF; | |
975 | ||
976 | if (!f.file) | |
977 | goto out; | |
978 | ||
979 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
980 | out: | |
981 | fdput(f); | |
982 | return ret; | |
983 | } | |
984 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
985 | ||
986 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) | |
987 | { | |
988 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); | |
989 | if (res > 0) | |
990 | flush_icache_range(addr, addr + len); | |
991 | return res; | |
992 | } | |
993 | EXPORT_SYMBOL(read_code); | |
994 | ||
995 | static int exec_mmap(struct mm_struct *mm) | |
996 | { | |
997 | struct task_struct *tsk; | |
998 | struct mm_struct *old_mm, *active_mm; | |
999 | ||
1000 | /* Notify parent that we're no longer interested in the old VM */ | |
1001 | tsk = current; | |
1002 | old_mm = current->mm; | |
1003 | mm_release(tsk, old_mm); | |
1004 | ||
1005 | if (old_mm) { | |
1006 | sync_mm_rss(old_mm); | |
1007 | /* | |
1008 | * Make sure that if there is a core dump in progress | |
1009 | * for the old mm, we get out and die instead of going | |
1010 | * through with the exec. We must hold mmap_sem around | |
1011 | * checking core_state and changing tsk->mm. | |
1012 | */ | |
1013 | down_read(&old_mm->mmap_sem); | |
1014 | if (unlikely(old_mm->core_state)) { | |
1015 | up_read(&old_mm->mmap_sem); | |
1016 | return -EINTR; | |
1017 | } | |
1018 | } | |
1019 | task_lock(tsk); | |
1020 | active_mm = tsk->active_mm; | |
1021 | tsk->mm = mm; | |
1022 | tsk->active_mm = mm; | |
1023 | activate_mm(active_mm, mm); | |
1024 | tsk->mm->vmacache_seqnum = 0; | |
1025 | vmacache_flush(tsk); | |
1026 | task_unlock(tsk); | |
1027 | if (old_mm) { | |
1028 | up_read(&old_mm->mmap_sem); | |
1029 | BUG_ON(active_mm != old_mm); | |
1030 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); | |
1031 | mm_update_next_owner(old_mm); | |
1032 | mmput(old_mm); | |
1033 | return 0; | |
1034 | } | |
1035 | mmdrop(active_mm); | |
1036 | return 0; | |
1037 | } | |
1038 | ||
1039 | /* | |
1040 | * This function makes sure the current process has its own signal table, | |
1041 | * so that flush_signal_handlers can later reset the handlers without | |
1042 | * disturbing other processes. (Other processes might share the signal | |
1043 | * table via the CLONE_SIGHAND option to clone().) | |
1044 | */ | |
1045 | static int de_thread(struct task_struct *tsk) | |
1046 | { | |
1047 | struct signal_struct *sig = tsk->signal; | |
1048 | struct sighand_struct *oldsighand = tsk->sighand; | |
1049 | spinlock_t *lock = &oldsighand->siglock; | |
1050 | ||
1051 | if (thread_group_empty(tsk)) | |
1052 | goto no_thread_group; | |
1053 | ||
1054 | /* | |
1055 | * Kill all other threads in the thread group. | |
1056 | */ | |
1057 | spin_lock_irq(lock); | |
1058 | if (signal_group_exit(sig)) { | |
1059 | /* | |
1060 | * Another group action in progress, just | |
1061 | * return so that the signal is processed. | |
1062 | */ | |
1063 | spin_unlock_irq(lock); | |
1064 | return -EAGAIN; | |
1065 | } | |
1066 | ||
1067 | sig->group_exit_task = tsk; | |
1068 | sig->notify_count = zap_other_threads(tsk); | |
1069 | if (!thread_group_leader(tsk)) | |
1070 | sig->notify_count--; | |
1071 | ||
1072 | while (sig->notify_count) { | |
1073 | __set_current_state(TASK_KILLABLE); | |
1074 | spin_unlock_irq(lock); | |
1075 | schedule(); | |
1076 | if (unlikely(__fatal_signal_pending(tsk))) | |
1077 | goto killed; | |
1078 | spin_lock_irq(lock); | |
1079 | } | |
1080 | spin_unlock_irq(lock); | |
1081 | ||
1082 | /* | |
1083 | * At this point all other threads have exited, all we have to | |
1084 | * do is to wait for the thread group leader to become inactive, | |
1085 | * and to assume its PID: | |
1086 | */ | |
1087 | if (!thread_group_leader(tsk)) { | |
1088 | struct task_struct *leader = tsk->group_leader; | |
1089 | ||
1090 | for (;;) { | |
1091 | threadgroup_change_begin(tsk); | |
1092 | write_lock_irq(&tasklist_lock); | |
1093 | /* | |
1094 | * Do this under tasklist_lock to ensure that | |
1095 | * exit_notify() can't miss ->group_exit_task | |
1096 | */ | |
1097 | sig->notify_count = -1; | |
1098 | if (likely(leader->exit_state)) | |
1099 | break; | |
1100 | __set_current_state(TASK_KILLABLE); | |
1101 | write_unlock_irq(&tasklist_lock); | |
1102 | threadgroup_change_end(tsk); | |
1103 | schedule(); | |
1104 | if (unlikely(__fatal_signal_pending(tsk))) | |
1105 | goto killed; | |
1106 | } | |
1107 | ||
1108 | /* | |
1109 | * The only record we have of the real-time age of a | |
1110 | * process, regardless of execs it's done, is start_time. | |
1111 | * All the past CPU time is accumulated in signal_struct | |
1112 | * from sister threads now dead. But in this non-leader | |
1113 | * exec, nothing survives from the original leader thread, | |
1114 | * whose birth marks the true age of this process now. | |
1115 | * When we take on its identity by switching to its PID, we | |
1116 | * also take its birthdate (always earlier than our own). | |
1117 | */ | |
1118 | tsk->start_time = leader->start_time; | |
1119 | tsk->real_start_time = leader->real_start_time; | |
1120 | ||
1121 | BUG_ON(!same_thread_group(leader, tsk)); | |
1122 | BUG_ON(has_group_leader_pid(tsk)); | |
1123 | /* | |
1124 | * An exec() starts a new thread group with the | |
1125 | * TGID of the previous thread group. Rehash the | |
1126 | * two threads with a switched PID, and release | |
1127 | * the former thread group leader: | |
1128 | */ | |
1129 | ||
1130 | /* Become a process group leader with the old leader's pid. | |
1131 | * The old leader becomes a thread of the this thread group. | |
1132 | * Note: The old leader also uses this pid until release_task | |
1133 | * is called. Odd but simple and correct. | |
1134 | */ | |
1135 | tsk->pid = leader->pid; | |
1136 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); | |
1137 | transfer_pid(leader, tsk, PIDTYPE_PGID); | |
1138 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
1139 | ||
1140 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1141 | list_replace_init(&leader->sibling, &tsk->sibling); | |
1142 | ||
1143 | tsk->group_leader = tsk; | |
1144 | leader->group_leader = tsk; | |
1145 | ||
1146 | tsk->exit_signal = SIGCHLD; | |
1147 | leader->exit_signal = -1; | |
1148 | ||
1149 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1150 | leader->exit_state = EXIT_DEAD; | |
1151 | ||
1152 | /* | |
1153 | * We are going to release_task()->ptrace_unlink() silently, | |
1154 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1155 | * the tracer wont't block again waiting for this thread. | |
1156 | */ | |
1157 | if (unlikely(leader->ptrace)) | |
1158 | __wake_up_parent(leader, leader->parent); | |
1159 | write_unlock_irq(&tasklist_lock); | |
1160 | threadgroup_change_end(tsk); | |
1161 | ||
1162 | release_task(leader); | |
1163 | } | |
1164 | ||
1165 | sig->group_exit_task = NULL; | |
1166 | sig->notify_count = 0; | |
1167 | ||
1168 | no_thread_group: | |
1169 | /* we have changed execution domain */ | |
1170 | tsk->exit_signal = SIGCHLD; | |
1171 | ||
1172 | #ifdef CONFIG_POSIX_TIMERS | |
1173 | exit_itimers(sig); | |
1174 | flush_itimer_signals(); | |
1175 | #endif | |
1176 | ||
1177 | if (atomic_read(&oldsighand->count) != 1) { | |
1178 | struct sighand_struct *newsighand; | |
1179 | /* | |
1180 | * This ->sighand is shared with the CLONE_SIGHAND | |
1181 | * but not CLONE_THREAD task, switch to the new one. | |
1182 | */ | |
1183 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
1184 | if (!newsighand) | |
1185 | return -ENOMEM; | |
1186 | ||
1187 | atomic_set(&newsighand->count, 1); | |
1188 | memcpy(newsighand->action, oldsighand->action, | |
1189 | sizeof(newsighand->action)); | |
1190 | ||
1191 | write_lock_irq(&tasklist_lock); | |
1192 | spin_lock(&oldsighand->siglock); | |
1193 | rcu_assign_pointer(tsk->sighand, newsighand); | |
1194 | spin_unlock(&oldsighand->siglock); | |
1195 | write_unlock_irq(&tasklist_lock); | |
1196 | ||
1197 | __cleanup_sighand(oldsighand); | |
1198 | } | |
1199 | ||
1200 | BUG_ON(!thread_group_leader(tsk)); | |
1201 | return 0; | |
1202 | ||
1203 | killed: | |
1204 | /* protects against exit_notify() and __exit_signal() */ | |
1205 | read_lock(&tasklist_lock); | |
1206 | sig->group_exit_task = NULL; | |
1207 | sig->notify_count = 0; | |
1208 | read_unlock(&tasklist_lock); | |
1209 | return -EAGAIN; | |
1210 | } | |
1211 | ||
1212 | char *get_task_comm(char *buf, struct task_struct *tsk) | |
1213 | { | |
1214 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1215 | task_lock(tsk); | |
1216 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1217 | task_unlock(tsk); | |
1218 | return buf; | |
1219 | } | |
1220 | EXPORT_SYMBOL_GPL(get_task_comm); | |
1221 | ||
1222 | /* | |
1223 | * These functions flushes out all traces of the currently running executable | |
1224 | * so that a new one can be started | |
1225 | */ | |
1226 | ||
1227 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) | |
1228 | { | |
1229 | task_lock(tsk); | |
1230 | trace_task_rename(tsk, buf); | |
1231 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
1232 | task_unlock(tsk); | |
1233 | perf_event_comm(tsk, exec); | |
1234 | } | |
1235 | ||
1236 | int flush_old_exec(struct linux_binprm * bprm) | |
1237 | { | |
1238 | int retval; | |
1239 | ||
1240 | /* | |
1241 | * Make sure we have a private signal table and that | |
1242 | * we are unassociated from the previous thread group. | |
1243 | */ | |
1244 | retval = de_thread(current); | |
1245 | if (retval) | |
1246 | goto out; | |
1247 | ||
1248 | /* | |
1249 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1250 | * not visibile until then. This also enables the update | |
1251 | * to be lockless. | |
1252 | */ | |
1253 | set_mm_exe_file(bprm->mm, bprm->file); | |
1254 | ||
1255 | /* | |
1256 | * Release all of the old mmap stuff | |
1257 | */ | |
1258 | acct_arg_size(bprm, 0); | |
1259 | retval = exec_mmap(bprm->mm); | |
1260 | if (retval) | |
1261 | goto out; | |
1262 | ||
1263 | bprm->mm = NULL; /* We're using it now */ | |
1264 | ||
1265 | set_fs(USER_DS); | |
1266 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | | |
1267 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
1268 | flush_thread(); | |
1269 | current->personality &= ~bprm->per_clear; | |
1270 | ||
1271 | /* | |
1272 | * We have to apply CLOEXEC before we change whether the process is | |
1273 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1274 | * trying to access the should-be-closed file descriptors of a process | |
1275 | * undergoing exec(2). | |
1276 | */ | |
1277 | do_close_on_exec(current->files); | |
1278 | return 0; | |
1279 | ||
1280 | out: | |
1281 | return retval; | |
1282 | } | |
1283 | EXPORT_SYMBOL(flush_old_exec); | |
1284 | ||
1285 | void would_dump(struct linux_binprm *bprm, struct file *file) | |
1286 | { | |
1287 | struct inode *inode = file_inode(file); | |
1288 | if (inode_permission(inode, MAY_READ) < 0) { | |
1289 | struct user_namespace *old, *user_ns; | |
1290 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; | |
1291 | ||
1292 | /* Ensure mm->user_ns contains the executable */ | |
1293 | user_ns = old = bprm->mm->user_ns; | |
1294 | while ((user_ns != &init_user_ns) && | |
1295 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1296 | user_ns = user_ns->parent; | |
1297 | ||
1298 | if (old != user_ns) { | |
1299 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1300 | put_user_ns(old); | |
1301 | } | |
1302 | } | |
1303 | } | |
1304 | EXPORT_SYMBOL(would_dump); | |
1305 | ||
1306 | void setup_new_exec(struct linux_binprm * bprm) | |
1307 | { | |
1308 | arch_pick_mmap_layout(current->mm); | |
1309 | ||
1310 | /* This is the point of no return */ | |
1311 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1312 | ||
1313 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) | |
1314 | set_dumpable(current->mm, SUID_DUMP_USER); | |
1315 | else | |
1316 | set_dumpable(current->mm, suid_dumpable); | |
1317 | ||
1318 | perf_event_exec(); | |
1319 | __set_task_comm(current, kbasename(bprm->filename), true); | |
1320 | ||
1321 | /* Set the new mm task size. We have to do that late because it may | |
1322 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1323 | * some architectures like powerpc | |
1324 | */ | |
1325 | current->mm->task_size = TASK_SIZE; | |
1326 | ||
1327 | /* install the new credentials */ | |
1328 | if (!uid_eq(bprm->cred->uid, current_euid()) || | |
1329 | !gid_eq(bprm->cred->gid, current_egid())) { | |
1330 | current->pdeath_signal = 0; | |
1331 | } else { | |
1332 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) | |
1333 | set_dumpable(current->mm, suid_dumpable); | |
1334 | } | |
1335 | ||
1336 | /* An exec changes our domain. We are no longer part of the thread | |
1337 | group */ | |
1338 | current->self_exec_id++; | |
1339 | flush_signal_handlers(current, 0); | |
1340 | } | |
1341 | EXPORT_SYMBOL(setup_new_exec); | |
1342 | ||
1343 | /* | |
1344 | * Prepare credentials and lock ->cred_guard_mutex. | |
1345 | * install_exec_creds() commits the new creds and drops the lock. | |
1346 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1347 | * and unlock. | |
1348 | */ | |
1349 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1350 | { | |
1351 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) | |
1352 | return -ERESTARTNOINTR; | |
1353 | ||
1354 | bprm->cred = prepare_exec_creds(); | |
1355 | if (likely(bprm->cred)) | |
1356 | return 0; | |
1357 | ||
1358 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1359 | return -ENOMEM; | |
1360 | } | |
1361 | ||
1362 | static void free_bprm(struct linux_binprm *bprm) | |
1363 | { | |
1364 | free_arg_pages(bprm); | |
1365 | if (bprm->cred) { | |
1366 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1367 | abort_creds(bprm->cred); | |
1368 | } | |
1369 | if (bprm->file) { | |
1370 | allow_write_access(bprm->file); | |
1371 | fput(bprm->file); | |
1372 | } | |
1373 | /* If a binfmt changed the interp, free it. */ | |
1374 | if (bprm->interp != bprm->filename) | |
1375 | kfree(bprm->interp); | |
1376 | kfree(bprm); | |
1377 | } | |
1378 | ||
1379 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) | |
1380 | { | |
1381 | /* If a binfmt changed the interp, free it first. */ | |
1382 | if (bprm->interp != bprm->filename) | |
1383 | kfree(bprm->interp); | |
1384 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1385 | if (!bprm->interp) | |
1386 | return -ENOMEM; | |
1387 | return 0; | |
1388 | } | |
1389 | EXPORT_SYMBOL(bprm_change_interp); | |
1390 | ||
1391 | /* | |
1392 | * install the new credentials for this executable | |
1393 | */ | |
1394 | void install_exec_creds(struct linux_binprm *bprm) | |
1395 | { | |
1396 | security_bprm_committing_creds(bprm); | |
1397 | ||
1398 | commit_creds(bprm->cred); | |
1399 | bprm->cred = NULL; | |
1400 | ||
1401 | /* | |
1402 | * Disable monitoring for regular users | |
1403 | * when executing setuid binaries. Must | |
1404 | * wait until new credentials are committed | |
1405 | * by commit_creds() above | |
1406 | */ | |
1407 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1408 | perf_event_exit_task(current); | |
1409 | /* | |
1410 | * cred_guard_mutex must be held at least to this point to prevent | |
1411 | * ptrace_attach() from altering our determination of the task's | |
1412 | * credentials; any time after this it may be unlocked. | |
1413 | */ | |
1414 | security_bprm_committed_creds(bprm); | |
1415 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1416 | } | |
1417 | EXPORT_SYMBOL(install_exec_creds); | |
1418 | ||
1419 | /* | |
1420 | * determine how safe it is to execute the proposed program | |
1421 | * - the caller must hold ->cred_guard_mutex to protect against | |
1422 | * PTRACE_ATTACH or seccomp thread-sync | |
1423 | */ | |
1424 | static void check_unsafe_exec(struct linux_binprm *bprm) | |
1425 | { | |
1426 | struct task_struct *p = current, *t; | |
1427 | unsigned n_fs; | |
1428 | ||
1429 | if (p->ptrace) { | |
1430 | if (ptracer_capable(p, current_user_ns())) | |
1431 | bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1432 | else | |
1433 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
1434 | } | |
1435 | ||
1436 | /* | |
1437 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1438 | * mess up. | |
1439 | */ | |
1440 | if (task_no_new_privs(current)) | |
1441 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; | |
1442 | ||
1443 | t = p; | |
1444 | n_fs = 1; | |
1445 | spin_lock(&p->fs->lock); | |
1446 | rcu_read_lock(); | |
1447 | while_each_thread(p, t) { | |
1448 | if (t->fs == p->fs) | |
1449 | n_fs++; | |
1450 | } | |
1451 | rcu_read_unlock(); | |
1452 | ||
1453 | if (p->fs->users > n_fs) | |
1454 | bprm->unsafe |= LSM_UNSAFE_SHARE; | |
1455 | else | |
1456 | p->fs->in_exec = 1; | |
1457 | spin_unlock(&p->fs->lock); | |
1458 | } | |
1459 | ||
1460 | static void bprm_fill_uid(struct linux_binprm *bprm) | |
1461 | { | |
1462 | struct inode *inode; | |
1463 | unsigned int mode; | |
1464 | kuid_t uid; | |
1465 | kgid_t gid; | |
1466 | ||
1467 | /* | |
1468 | * Since this can be called multiple times (via prepare_binprm), | |
1469 | * we must clear any previous work done when setting set[ug]id | |
1470 | * bits from any earlier bprm->file uses (for example when run | |
1471 | * first for a setuid script then again for its interpreter). | |
1472 | */ | |
1473 | bprm->cred->euid = current_euid(); | |
1474 | bprm->cred->egid = current_egid(); | |
1475 | ||
1476 | if (!mnt_may_suid(bprm->file->f_path.mnt)) | |
1477 | return; | |
1478 | ||
1479 | if (task_no_new_privs(current)) | |
1480 | return; | |
1481 | ||
1482 | inode = file_inode(bprm->file); | |
1483 | mode = READ_ONCE(inode->i_mode); | |
1484 | if (!(mode & (S_ISUID|S_ISGID))) | |
1485 | return; | |
1486 | ||
1487 | /* Be careful if suid/sgid is set */ | |
1488 | inode_lock(inode); | |
1489 | ||
1490 | /* reload atomically mode/uid/gid now that lock held */ | |
1491 | mode = inode->i_mode; | |
1492 | uid = inode->i_uid; | |
1493 | gid = inode->i_gid; | |
1494 | inode_unlock(inode); | |
1495 | ||
1496 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1497 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1498 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1499 | return; | |
1500 | ||
1501 | if (mode & S_ISUID) { | |
1502 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1503 | bprm->cred->euid = uid; | |
1504 | } | |
1505 | ||
1506 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1507 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1508 | bprm->cred->egid = gid; | |
1509 | } | |
1510 | } | |
1511 | ||
1512 | /* | |
1513 | * Fill the binprm structure from the inode. | |
1514 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1515 | * | |
1516 | * This may be called multiple times for binary chains (scripts for example). | |
1517 | */ | |
1518 | int prepare_binprm(struct linux_binprm *bprm) | |
1519 | { | |
1520 | int retval; | |
1521 | ||
1522 | bprm_fill_uid(bprm); | |
1523 | ||
1524 | /* fill in binprm security blob */ | |
1525 | retval = security_bprm_set_creds(bprm); | |
1526 | if (retval) | |
1527 | return retval; | |
1528 | bprm->cred_prepared = 1; | |
1529 | ||
1530 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
1531 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1532 | } | |
1533 | ||
1534 | EXPORT_SYMBOL(prepare_binprm); | |
1535 | ||
1536 | /* | |
1537 | * Arguments are '\0' separated strings found at the location bprm->p | |
1538 | * points to; chop off the first by relocating brpm->p to right after | |
1539 | * the first '\0' encountered. | |
1540 | */ | |
1541 | int remove_arg_zero(struct linux_binprm *bprm) | |
1542 | { | |
1543 | int ret = 0; | |
1544 | unsigned long offset; | |
1545 | char *kaddr; | |
1546 | struct page *page; | |
1547 | ||
1548 | if (!bprm->argc) | |
1549 | return 0; | |
1550 | ||
1551 | do { | |
1552 | offset = bprm->p & ~PAGE_MASK; | |
1553 | page = get_arg_page(bprm, bprm->p, 0); | |
1554 | if (!page) { | |
1555 | ret = -EFAULT; | |
1556 | goto out; | |
1557 | } | |
1558 | kaddr = kmap_atomic(page); | |
1559 | ||
1560 | for (; offset < PAGE_SIZE && kaddr[offset]; | |
1561 | offset++, bprm->p++) | |
1562 | ; | |
1563 | ||
1564 | kunmap_atomic(kaddr); | |
1565 | put_arg_page(page); | |
1566 | } while (offset == PAGE_SIZE); | |
1567 | ||
1568 | bprm->p++; | |
1569 | bprm->argc--; | |
1570 | ret = 0; | |
1571 | ||
1572 | out: | |
1573 | return ret; | |
1574 | } | |
1575 | EXPORT_SYMBOL(remove_arg_zero); | |
1576 | ||
1577 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1578 | /* | |
1579 | * cycle the list of binary formats handler, until one recognizes the image | |
1580 | */ | |
1581 | int search_binary_handler(struct linux_binprm *bprm) | |
1582 | { | |
1583 | bool need_retry = IS_ENABLED(CONFIG_MODULES); | |
1584 | struct linux_binfmt *fmt; | |
1585 | int retval; | |
1586 | ||
1587 | /* This allows 4 levels of binfmt rewrites before failing hard. */ | |
1588 | if (bprm->recursion_depth > 5) | |
1589 | return -ELOOP; | |
1590 | ||
1591 | retval = security_bprm_check(bprm); | |
1592 | if (retval) | |
1593 | return retval; | |
1594 | ||
1595 | retval = -ENOENT; | |
1596 | retry: | |
1597 | read_lock(&binfmt_lock); | |
1598 | list_for_each_entry(fmt, &formats, lh) { | |
1599 | if (!try_module_get(fmt->module)) | |
1600 | continue; | |
1601 | read_unlock(&binfmt_lock); | |
1602 | bprm->recursion_depth++; | |
1603 | retval = fmt->load_binary(bprm); | |
1604 | read_lock(&binfmt_lock); | |
1605 | put_binfmt(fmt); | |
1606 | bprm->recursion_depth--; | |
1607 | if (retval < 0 && !bprm->mm) { | |
1608 | /* we got to flush_old_exec() and failed after it */ | |
1609 | read_unlock(&binfmt_lock); | |
1610 | force_sigsegv(SIGSEGV, current); | |
1611 | return retval; | |
1612 | } | |
1613 | if (retval != -ENOEXEC || !bprm->file) { | |
1614 | read_unlock(&binfmt_lock); | |
1615 | return retval; | |
1616 | } | |
1617 | } | |
1618 | read_unlock(&binfmt_lock); | |
1619 | ||
1620 | if (need_retry) { | |
1621 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && | |
1622 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1623 | return retval; | |
1624 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) | |
1625 | return retval; | |
1626 | need_retry = false; | |
1627 | goto retry; | |
1628 | } | |
1629 | ||
1630 | return retval; | |
1631 | } | |
1632 | EXPORT_SYMBOL(search_binary_handler); | |
1633 | ||
1634 | static int exec_binprm(struct linux_binprm *bprm) | |
1635 | { | |
1636 | pid_t old_pid, old_vpid; | |
1637 | int ret; | |
1638 | ||
1639 | /* Need to fetch pid before load_binary changes it */ | |
1640 | old_pid = current->pid; | |
1641 | rcu_read_lock(); | |
1642 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1643 | rcu_read_unlock(); | |
1644 | ||
1645 | ret = search_binary_handler(bprm); | |
1646 | if (ret >= 0) { | |
1647 | audit_bprm(bprm); | |
1648 | trace_sched_process_exec(current, old_pid, bprm); | |
1649 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
1650 | proc_exec_connector(current); | |
1651 | } | |
1652 | ||
1653 | return ret; | |
1654 | } | |
1655 | ||
1656 | /* | |
1657 | * sys_execve() executes a new program. | |
1658 | */ | |
1659 | static int do_execveat_common(int fd, struct filename *filename, | |
1660 | struct user_arg_ptr argv, | |
1661 | struct user_arg_ptr envp, | |
1662 | int flags) | |
1663 | { | |
1664 | char *pathbuf = NULL; | |
1665 | struct linux_binprm *bprm; | |
1666 | struct file *file; | |
1667 | struct files_struct *displaced; | |
1668 | int retval; | |
1669 | ||
1670 | if (IS_ERR(filename)) | |
1671 | return PTR_ERR(filename); | |
1672 | ||
1673 | /* | |
1674 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1675 | * set*uid() to execve() because too many poorly written programs | |
1676 | * don't check setuid() return code. Here we additionally recheck | |
1677 | * whether NPROC limit is still exceeded. | |
1678 | */ | |
1679 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
1680 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { | |
1681 | retval = -EAGAIN; | |
1682 | goto out_ret; | |
1683 | } | |
1684 | ||
1685 | /* We're below the limit (still or again), so we don't want to make | |
1686 | * further execve() calls fail. */ | |
1687 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1688 | ||
1689 | retval = unshare_files(&displaced); | |
1690 | if (retval) | |
1691 | goto out_ret; | |
1692 | ||
1693 | retval = -ENOMEM; | |
1694 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); | |
1695 | if (!bprm) | |
1696 | goto out_files; | |
1697 | ||
1698 | retval = prepare_bprm_creds(bprm); | |
1699 | if (retval) | |
1700 | goto out_free; | |
1701 | ||
1702 | check_unsafe_exec(bprm); | |
1703 | current->in_execve = 1; | |
1704 | ||
1705 | file = do_open_execat(fd, filename, flags); | |
1706 | retval = PTR_ERR(file); | |
1707 | if (IS_ERR(file)) | |
1708 | goto out_unmark; | |
1709 | ||
1710 | sched_exec(); | |
1711 | ||
1712 | bprm->file = file; | |
1713 | if (fd == AT_FDCWD || filename->name[0] == '/') { | |
1714 | bprm->filename = filename->name; | |
1715 | } else { | |
1716 | if (filename->name[0] == '\0') | |
1717 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1718 | else | |
1719 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1720 | fd, filename->name); | |
1721 | if (!pathbuf) { | |
1722 | retval = -ENOMEM; | |
1723 | goto out_unmark; | |
1724 | } | |
1725 | /* | |
1726 | * Record that a name derived from an O_CLOEXEC fd will be | |
1727 | * inaccessible after exec. Relies on having exclusive access to | |
1728 | * current->files (due to unshare_files above). | |
1729 | */ | |
1730 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1731 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1732 | bprm->filename = pathbuf; | |
1733 | } | |
1734 | bprm->interp = bprm->filename; | |
1735 | ||
1736 | retval = bprm_mm_init(bprm); | |
1737 | if (retval) | |
1738 | goto out_unmark; | |
1739 | ||
1740 | bprm->argc = count(argv, MAX_ARG_STRINGS); | |
1741 | if ((retval = bprm->argc) < 0) | |
1742 | goto out; | |
1743 | ||
1744 | bprm->envc = count(envp, MAX_ARG_STRINGS); | |
1745 | if ((retval = bprm->envc) < 0) | |
1746 | goto out; | |
1747 | ||
1748 | retval = prepare_binprm(bprm); | |
1749 | if (retval < 0) | |
1750 | goto out; | |
1751 | ||
1752 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1753 | if (retval < 0) | |
1754 | goto out; | |
1755 | ||
1756 | bprm->exec = bprm->p; | |
1757 | retval = copy_strings(bprm->envc, envp, bprm); | |
1758 | if (retval < 0) | |
1759 | goto out; | |
1760 | ||
1761 | retval = copy_strings(bprm->argc, argv, bprm); | |
1762 | if (retval < 0) | |
1763 | goto out; | |
1764 | ||
1765 | would_dump(bprm, bprm->file); | |
1766 | ||
1767 | retval = exec_binprm(bprm); | |
1768 | if (retval < 0) | |
1769 | goto out; | |
1770 | ||
1771 | /* execve succeeded */ | |
1772 | current->fs->in_exec = 0; | |
1773 | current->in_execve = 0; | |
1774 | acct_update_integrals(current); | |
1775 | task_numa_free(current); | |
1776 | free_bprm(bprm); | |
1777 | kfree(pathbuf); | |
1778 | putname(filename); | |
1779 | if (displaced) | |
1780 | put_files_struct(displaced); | |
1781 | return retval; | |
1782 | ||
1783 | out: | |
1784 | if (bprm->mm) { | |
1785 | acct_arg_size(bprm, 0); | |
1786 | mmput(bprm->mm); | |
1787 | } | |
1788 | ||
1789 | out_unmark: | |
1790 | current->fs->in_exec = 0; | |
1791 | current->in_execve = 0; | |
1792 | ||
1793 | out_free: | |
1794 | free_bprm(bprm); | |
1795 | kfree(pathbuf); | |
1796 | ||
1797 | out_files: | |
1798 | if (displaced) | |
1799 | reset_files_struct(displaced); | |
1800 | out_ret: | |
1801 | putname(filename); | |
1802 | return retval; | |
1803 | } | |
1804 | ||
1805 | int do_execve(struct filename *filename, | |
1806 | const char __user *const __user *__argv, | |
1807 | const char __user *const __user *__envp) | |
1808 | { | |
1809 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1810 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1811 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1812 | } | |
1813 | ||
1814 | int do_execveat(int fd, struct filename *filename, | |
1815 | const char __user *const __user *__argv, | |
1816 | const char __user *const __user *__envp, | |
1817 | int flags) | |
1818 | { | |
1819 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1820 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1821 | ||
1822 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1823 | } | |
1824 | ||
1825 | #ifdef CONFIG_COMPAT | |
1826 | static int compat_do_execve(struct filename *filename, | |
1827 | const compat_uptr_t __user *__argv, | |
1828 | const compat_uptr_t __user *__envp) | |
1829 | { | |
1830 | struct user_arg_ptr argv = { | |
1831 | .is_compat = true, | |
1832 | .ptr.compat = __argv, | |
1833 | }; | |
1834 | struct user_arg_ptr envp = { | |
1835 | .is_compat = true, | |
1836 | .ptr.compat = __envp, | |
1837 | }; | |
1838 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1839 | } | |
1840 | ||
1841 | static int compat_do_execveat(int fd, struct filename *filename, | |
1842 | const compat_uptr_t __user *__argv, | |
1843 | const compat_uptr_t __user *__envp, | |
1844 | int flags) | |
1845 | { | |
1846 | struct user_arg_ptr argv = { | |
1847 | .is_compat = true, | |
1848 | .ptr.compat = __argv, | |
1849 | }; | |
1850 | struct user_arg_ptr envp = { | |
1851 | .is_compat = true, | |
1852 | .ptr.compat = __envp, | |
1853 | }; | |
1854 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1855 | } | |
1856 | #endif | |
1857 | ||
1858 | void set_binfmt(struct linux_binfmt *new) | |
1859 | { | |
1860 | struct mm_struct *mm = current->mm; | |
1861 | ||
1862 | if (mm->binfmt) | |
1863 | module_put(mm->binfmt->module); | |
1864 | ||
1865 | mm->binfmt = new; | |
1866 | if (new) | |
1867 | __module_get(new->module); | |
1868 | } | |
1869 | EXPORT_SYMBOL(set_binfmt); | |
1870 | ||
1871 | /* | |
1872 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. | |
1873 | */ | |
1874 | void set_dumpable(struct mm_struct *mm, int value) | |
1875 | { | |
1876 | unsigned long old, new; | |
1877 | ||
1878 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) | |
1879 | return; | |
1880 | ||
1881 | do { | |
1882 | old = ACCESS_ONCE(mm->flags); | |
1883 | new = (old & ~MMF_DUMPABLE_MASK) | value; | |
1884 | } while (cmpxchg(&mm->flags, old, new) != old); | |
1885 | } | |
1886 | ||
1887 | SYSCALL_DEFINE3(execve, | |
1888 | const char __user *, filename, | |
1889 | const char __user *const __user *, argv, | |
1890 | const char __user *const __user *, envp) | |
1891 | { | |
1892 | return do_execve(getname(filename), argv, envp); | |
1893 | } | |
1894 | ||
1895 | SYSCALL_DEFINE5(execveat, | |
1896 | int, fd, const char __user *, filename, | |
1897 | const char __user *const __user *, argv, | |
1898 | const char __user *const __user *, envp, | |
1899 | int, flags) | |
1900 | { | |
1901 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1902 | ||
1903 | return do_execveat(fd, | |
1904 | getname_flags(filename, lookup_flags, NULL), | |
1905 | argv, envp, flags); | |
1906 | } | |
1907 | ||
1908 | #ifdef CONFIG_COMPAT | |
1909 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, | |
1910 | const compat_uptr_t __user *, argv, | |
1911 | const compat_uptr_t __user *, envp) | |
1912 | { | |
1913 | return compat_do_execve(getname(filename), argv, envp); | |
1914 | } | |
1915 | ||
1916 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1917 | const char __user *, filename, | |
1918 | const compat_uptr_t __user *, argv, | |
1919 | const compat_uptr_t __user *, envp, | |
1920 | int, flags) | |
1921 | { | |
1922 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1923 | ||
1924 | return compat_do_execveat(fd, | |
1925 | getname_flags(filename, lookup_flags, NULL), | |
1926 | argv, envp, flags); | |
1927 | } | |
1928 | #endif |