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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/sched/mm.h> | |
36 | #include <linux/sched/coredump.h> | |
37 | #include <linux/pagemap.h> | |
38 | #include <linux/perf_event.h> | |
39 | #include <linux/highmem.h> | |
40 | #include <linux/spinlock.h> | |
41 | #include <linux/key.h> | |
42 | #include <linux/personality.h> | |
43 | #include <linux/binfmts.h> | |
44 | #include <linux/utsname.h> | |
45 | #include <linux/pid_namespace.h> | |
46 | #include <linux/module.h> | |
47 | #include <linux/namei.h> | |
48 | #include <linux/mount.h> | |
49 | #include <linux/security.h> | |
50 | #include <linux/syscalls.h> | |
51 | #include <linux/tsacct_kern.h> | |
52 | #include <linux/cn_proc.h> | |
53 | #include <linux/audit.h> | |
54 | #include <linux/tracehook.h> | |
55 | #include <linux/kmod.h> | |
56 | #include <linux/fsnotify.h> | |
57 | #include <linux/fs_struct.h> | |
58 | #include <linux/pipe_fs_i.h> | |
59 | #include <linux/oom.h> | |
60 | #include <linux/compat.h> | |
61 | #include <linux/vmalloc.h> | |
62 | ||
63 | #include <linux/uaccess.h> | |
64 | #include <asm/mmu_context.h> | |
65 | #include <asm/tlb.h> | |
66 | ||
67 | #include <trace/events/task.h> | |
68 | #include "internal.h" | |
69 | ||
70 | #include <trace/events/sched.h> | |
71 | ||
72 | int suid_dumpable = 0; | |
73 | ||
74 | static LIST_HEAD(formats); | |
75 | static DEFINE_RWLOCK(binfmt_lock); | |
76 | ||
77 | void __register_binfmt(struct linux_binfmt * fmt, int insert) | |
78 | { | |
79 | BUG_ON(!fmt); | |
80 | if (WARN_ON(!fmt->load_binary)) | |
81 | return; | |
82 | write_lock(&binfmt_lock); | |
83 | insert ? list_add(&fmt->lh, &formats) : | |
84 | list_add_tail(&fmt->lh, &formats); | |
85 | write_unlock(&binfmt_lock); | |
86 | } | |
87 | ||
88 | EXPORT_SYMBOL(__register_binfmt); | |
89 | ||
90 | void unregister_binfmt(struct linux_binfmt * fmt) | |
91 | { | |
92 | write_lock(&binfmt_lock); | |
93 | list_del(&fmt->lh); | |
94 | write_unlock(&binfmt_lock); | |
95 | } | |
96 | ||
97 | EXPORT_SYMBOL(unregister_binfmt); | |
98 | ||
99 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
100 | { | |
101 | module_put(fmt->module); | |
102 | } | |
103 | ||
104 | bool path_noexec(const struct path *path) | |
105 | { | |
106 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
107 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
108 | } | |
109 | ||
110 | #ifdef CONFIG_USELIB | |
111 | /* | |
112 | * Note that a shared library must be both readable and executable due to | |
113 | * security reasons. | |
114 | * | |
115 | * Also note that we take the address to load from from the file itself. | |
116 | */ | |
117 | SYSCALL_DEFINE1(uselib, const char __user *, library) | |
118 | { | |
119 | struct linux_binfmt *fmt; | |
120 | struct file *file; | |
121 | struct filename *tmp = getname(library); | |
122 | int error = PTR_ERR(tmp); | |
123 | static const struct open_flags uselib_flags = { | |
124 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
125 | .acc_mode = MAY_READ | MAY_EXEC, | |
126 | .intent = LOOKUP_OPEN, | |
127 | .lookup_flags = LOOKUP_FOLLOW, | |
128 | }; | |
129 | ||
130 | if (IS_ERR(tmp)) | |
131 | goto out; | |
132 | ||
133 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); | |
134 | putname(tmp); | |
135 | error = PTR_ERR(file); | |
136 | if (IS_ERR(file)) | |
137 | goto out; | |
138 | ||
139 | error = -EINVAL; | |
140 | if (!S_ISREG(file_inode(file)->i_mode)) | |
141 | goto exit; | |
142 | ||
143 | error = -EACCES; | |
144 | if (path_noexec(&file->f_path)) | |
145 | goto exit; | |
146 | ||
147 | fsnotify_open(file); | |
148 | ||
149 | error = -ENOEXEC; | |
150 | ||
151 | read_lock(&binfmt_lock); | |
152 | list_for_each_entry(fmt, &formats, lh) { | |
153 | if (!fmt->load_shlib) | |
154 | continue; | |
155 | if (!try_module_get(fmt->module)) | |
156 | continue; | |
157 | read_unlock(&binfmt_lock); | |
158 | error = fmt->load_shlib(file); | |
159 | read_lock(&binfmt_lock); | |
160 | put_binfmt(fmt); | |
161 | if (error != -ENOEXEC) | |
162 | break; | |
163 | } | |
164 | read_unlock(&binfmt_lock); | |
165 | exit: | |
166 | fput(file); | |
167 | out: | |
168 | return error; | |
169 | } | |
170 | #endif /* #ifdef CONFIG_USELIB */ | |
171 | ||
172 | #ifdef CONFIG_MMU | |
173 | /* | |
174 | * The nascent bprm->mm is not visible until exec_mmap() but it can | |
175 | * use a lot of memory, account these pages in current->mm temporary | |
176 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we | |
177 | * change the counter back via acct_arg_size(0). | |
178 | */ | |
179 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) | |
180 | { | |
181 | struct mm_struct *mm = current->mm; | |
182 | long diff = (long)(pages - bprm->vma_pages); | |
183 | ||
184 | if (!mm || !diff) | |
185 | return; | |
186 | ||
187 | bprm->vma_pages = pages; | |
188 | add_mm_counter(mm, MM_ANONPAGES, diff); | |
189 | } | |
190 | ||
191 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
192 | int write) | |
193 | { | |
194 | struct page *page; | |
195 | int ret; | |
196 | unsigned int gup_flags = FOLL_FORCE; | |
197 | ||
198 | #ifdef CONFIG_STACK_GROWSUP | |
199 | if (write) { | |
200 | ret = expand_downwards(bprm->vma, pos); | |
201 | if (ret < 0) | |
202 | return NULL; | |
203 | } | |
204 | #endif | |
205 | ||
206 | if (write) | |
207 | gup_flags |= FOLL_WRITE; | |
208 | ||
209 | /* | |
210 | * We are doing an exec(). 'current' is the process | |
211 | * doing the exec and bprm->mm is the new process's mm. | |
212 | */ | |
213 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, | |
214 | &page, NULL, NULL); | |
215 | if (ret <= 0) | |
216 | return NULL; | |
217 | ||
218 | if (write) { | |
219 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
220 | struct rlimit *rlim; | |
221 | ||
222 | acct_arg_size(bprm, size / PAGE_SIZE); | |
223 | ||
224 | /* | |
225 | * We've historically supported up to 32 pages (ARG_MAX) | |
226 | * of argument strings even with small stacks | |
227 | */ | |
228 | if (size <= ARG_MAX) | |
229 | return page; | |
230 | ||
231 | /* | |
232 | * Limit to 1/4-th the stack size for the argv+env strings. | |
233 | * This ensures that: | |
234 | * - the remaining binfmt code will not run out of stack space, | |
235 | * - the program will have a reasonable amount of stack left | |
236 | * to work from. | |
237 | */ | |
238 | rlim = current->signal->rlim; | |
239 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { | |
240 | put_page(page); | |
241 | return NULL; | |
242 | } | |
243 | } | |
244 | ||
245 | return page; | |
246 | } | |
247 | ||
248 | static void put_arg_page(struct page *page) | |
249 | { | |
250 | put_page(page); | |
251 | } | |
252 | ||
253 | static void free_arg_pages(struct linux_binprm *bprm) | |
254 | { | |
255 | } | |
256 | ||
257 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
258 | struct page *page) | |
259 | { | |
260 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
261 | } | |
262 | ||
263 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
264 | { | |
265 | int err; | |
266 | struct vm_area_struct *vma = NULL; | |
267 | struct mm_struct *mm = bprm->mm; | |
268 | ||
269 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
270 | if (!vma) | |
271 | return -ENOMEM; | |
272 | ||
273 | if (down_write_killable(&mm->mmap_sem)) { | |
274 | err = -EINTR; | |
275 | goto err_free; | |
276 | } | |
277 | vma->vm_mm = mm; | |
278 | ||
279 | /* | |
280 | * Place the stack at the largest stack address the architecture | |
281 | * supports. Later, we'll move this to an appropriate place. We don't | |
282 | * use STACK_TOP because that can depend on attributes which aren't | |
283 | * configured yet. | |
284 | */ | |
285 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); | |
286 | vma->vm_end = STACK_TOP_MAX; | |
287 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
288 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; | |
289 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); | |
290 | INIT_LIST_HEAD(&vma->anon_vma_chain); | |
291 | ||
292 | err = insert_vm_struct(mm, vma); | |
293 | if (err) | |
294 | goto err; | |
295 | ||
296 | mm->stack_vm = mm->total_vm = 1; | |
297 | arch_bprm_mm_init(mm, vma); | |
298 | up_write(&mm->mmap_sem); | |
299 | bprm->p = vma->vm_end - sizeof(void *); | |
300 | return 0; | |
301 | err: | |
302 | up_write(&mm->mmap_sem); | |
303 | err_free: | |
304 | bprm->vma = NULL; | |
305 | kmem_cache_free(vm_area_cachep, vma); | |
306 | return err; | |
307 | } | |
308 | ||
309 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
310 | { | |
311 | return len <= MAX_ARG_STRLEN; | |
312 | } | |
313 | ||
314 | #else | |
315 | ||
316 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) | |
317 | { | |
318 | } | |
319 | ||
320 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
321 | int write) | |
322 | { | |
323 | struct page *page; | |
324 | ||
325 | page = bprm->page[pos / PAGE_SIZE]; | |
326 | if (!page && write) { | |
327 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
328 | if (!page) | |
329 | return NULL; | |
330 | bprm->page[pos / PAGE_SIZE] = page; | |
331 | } | |
332 | ||
333 | return page; | |
334 | } | |
335 | ||
336 | static void put_arg_page(struct page *page) | |
337 | { | |
338 | } | |
339 | ||
340 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
341 | { | |
342 | if (bprm->page[i]) { | |
343 | __free_page(bprm->page[i]); | |
344 | bprm->page[i] = NULL; | |
345 | } | |
346 | } | |
347 | ||
348 | static void free_arg_pages(struct linux_binprm *bprm) | |
349 | { | |
350 | int i; | |
351 | ||
352 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
353 | free_arg_page(bprm, i); | |
354 | } | |
355 | ||
356 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
357 | struct page *page) | |
358 | { | |
359 | } | |
360 | ||
361 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
362 | { | |
363 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
364 | return 0; | |
365 | } | |
366 | ||
367 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
368 | { | |
369 | return len <= bprm->p; | |
370 | } | |
371 | ||
372 | #endif /* CONFIG_MMU */ | |
373 | ||
374 | /* | |
375 | * Create a new mm_struct and populate it with a temporary stack | |
376 | * vm_area_struct. We don't have enough context at this point to set the stack | |
377 | * flags, permissions, and offset, so we use temporary values. We'll update | |
378 | * them later in setup_arg_pages(). | |
379 | */ | |
380 | static int bprm_mm_init(struct linux_binprm *bprm) | |
381 | { | |
382 | int err; | |
383 | struct mm_struct *mm = NULL; | |
384 | ||
385 | bprm->mm = mm = mm_alloc(); | |
386 | err = -ENOMEM; | |
387 | if (!mm) | |
388 | goto err; | |
389 | ||
390 | err = __bprm_mm_init(bprm); | |
391 | if (err) | |
392 | goto err; | |
393 | ||
394 | return 0; | |
395 | ||
396 | err: | |
397 | if (mm) { | |
398 | bprm->mm = NULL; | |
399 | mmdrop(mm); | |
400 | } | |
401 | ||
402 | return err; | |
403 | } | |
404 | ||
405 | struct user_arg_ptr { | |
406 | #ifdef CONFIG_COMPAT | |
407 | bool is_compat; | |
408 | #endif | |
409 | union { | |
410 | const char __user *const __user *native; | |
411 | #ifdef CONFIG_COMPAT | |
412 | const compat_uptr_t __user *compat; | |
413 | #endif | |
414 | } ptr; | |
415 | }; | |
416 | ||
417 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
418 | { | |
419 | const char __user *native; | |
420 | ||
421 | #ifdef CONFIG_COMPAT | |
422 | if (unlikely(argv.is_compat)) { | |
423 | compat_uptr_t compat; | |
424 | ||
425 | if (get_user(compat, argv.ptr.compat + nr)) | |
426 | return ERR_PTR(-EFAULT); | |
427 | ||
428 | return compat_ptr(compat); | |
429 | } | |
430 | #endif | |
431 | ||
432 | if (get_user(native, argv.ptr.native + nr)) | |
433 | return ERR_PTR(-EFAULT); | |
434 | ||
435 | return native; | |
436 | } | |
437 | ||
438 | /* | |
439 | * count() counts the number of strings in array ARGV. | |
440 | */ | |
441 | static int count(struct user_arg_ptr argv, int max) | |
442 | { | |
443 | int i = 0; | |
444 | ||
445 | if (argv.ptr.native != NULL) { | |
446 | for (;;) { | |
447 | const char __user *p = get_user_arg_ptr(argv, i); | |
448 | ||
449 | if (!p) | |
450 | break; | |
451 | ||
452 | if (IS_ERR(p)) | |
453 | return -EFAULT; | |
454 | ||
455 | if (i >= max) | |
456 | return -E2BIG; | |
457 | ++i; | |
458 | ||
459 | if (fatal_signal_pending(current)) | |
460 | return -ERESTARTNOHAND; | |
461 | cond_resched(); | |
462 | } | |
463 | } | |
464 | return i; | |
465 | } | |
466 | ||
467 | /* | |
468 | * 'copy_strings()' copies argument/environment strings from the old | |
469 | * processes's memory to the new process's stack. The call to get_user_pages() | |
470 | * ensures the destination page is created and not swapped out. | |
471 | */ | |
472 | static int copy_strings(int argc, struct user_arg_ptr argv, | |
473 | struct linux_binprm *bprm) | |
474 | { | |
475 | struct page *kmapped_page = NULL; | |
476 | char *kaddr = NULL; | |
477 | unsigned long kpos = 0; | |
478 | int ret; | |
479 | ||
480 | while (argc-- > 0) { | |
481 | const char __user *str; | |
482 | int len; | |
483 | unsigned long pos; | |
484 | ||
485 | ret = -EFAULT; | |
486 | str = get_user_arg_ptr(argv, argc); | |
487 | if (IS_ERR(str)) | |
488 | goto out; | |
489 | ||
490 | len = strnlen_user(str, MAX_ARG_STRLEN); | |
491 | if (!len) | |
492 | goto out; | |
493 | ||
494 | ret = -E2BIG; | |
495 | if (!valid_arg_len(bprm, len)) | |
496 | goto out; | |
497 | ||
498 | /* We're going to work our way backwords. */ | |
499 | pos = bprm->p; | |
500 | str += len; | |
501 | bprm->p -= len; | |
502 | ||
503 | while (len > 0) { | |
504 | int offset, bytes_to_copy; | |
505 | ||
506 | if (fatal_signal_pending(current)) { | |
507 | ret = -ERESTARTNOHAND; | |
508 | goto out; | |
509 | } | |
510 | cond_resched(); | |
511 | ||
512 | offset = pos % PAGE_SIZE; | |
513 | if (offset == 0) | |
514 | offset = PAGE_SIZE; | |
515 | ||
516 | bytes_to_copy = offset; | |
517 | if (bytes_to_copy > len) | |
518 | bytes_to_copy = len; | |
519 | ||
520 | offset -= bytes_to_copy; | |
521 | pos -= bytes_to_copy; | |
522 | str -= bytes_to_copy; | |
523 | len -= bytes_to_copy; | |
524 | ||
525 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
526 | struct page *page; | |
527 | ||
528 | page = get_arg_page(bprm, pos, 1); | |
529 | if (!page) { | |
530 | ret = -E2BIG; | |
531 | goto out; | |
532 | } | |
533 | ||
534 | if (kmapped_page) { | |
535 | flush_kernel_dcache_page(kmapped_page); | |
536 | kunmap(kmapped_page); | |
537 | put_arg_page(kmapped_page); | |
538 | } | |
539 | kmapped_page = page; | |
540 | kaddr = kmap(kmapped_page); | |
541 | kpos = pos & PAGE_MASK; | |
542 | flush_arg_page(bprm, kpos, kmapped_page); | |
543 | } | |
544 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { | |
545 | ret = -EFAULT; | |
546 | goto out; | |
547 | } | |
548 | } | |
549 | } | |
550 | ret = 0; | |
551 | out: | |
552 | if (kmapped_page) { | |
553 | flush_kernel_dcache_page(kmapped_page); | |
554 | kunmap(kmapped_page); | |
555 | put_arg_page(kmapped_page); | |
556 | } | |
557 | return ret; | |
558 | } | |
559 | ||
560 | /* | |
561 | * Like copy_strings, but get argv and its values from kernel memory. | |
562 | */ | |
563 | int copy_strings_kernel(int argc, const char *const *__argv, | |
564 | struct linux_binprm *bprm) | |
565 | { | |
566 | int r; | |
567 | mm_segment_t oldfs = get_fs(); | |
568 | struct user_arg_ptr argv = { | |
569 | .ptr.native = (const char __user *const __user *)__argv, | |
570 | }; | |
571 | ||
572 | set_fs(KERNEL_DS); | |
573 | r = copy_strings(argc, argv, bprm); | |
574 | set_fs(oldfs); | |
575 | ||
576 | return r; | |
577 | } | |
578 | EXPORT_SYMBOL(copy_strings_kernel); | |
579 | ||
580 | #ifdef CONFIG_MMU | |
581 | ||
582 | /* | |
583 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once | |
584 | * the binfmt code determines where the new stack should reside, we shift it to | |
585 | * its final location. The process proceeds as follows: | |
586 | * | |
587 | * 1) Use shift to calculate the new vma endpoints. | |
588 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
589 | * arguments passed to subsequent functions are consistent. | |
590 | * 3) Move vma's page tables to the new range. | |
591 | * 4) Free up any cleared pgd range. | |
592 | * 5) Shrink the vma to cover only the new range. | |
593 | */ | |
594 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) | |
595 | { | |
596 | struct mm_struct *mm = vma->vm_mm; | |
597 | unsigned long old_start = vma->vm_start; | |
598 | unsigned long old_end = vma->vm_end; | |
599 | unsigned long length = old_end - old_start; | |
600 | unsigned long new_start = old_start - shift; | |
601 | unsigned long new_end = old_end - shift; | |
602 | struct mmu_gather tlb; | |
603 | ||
604 | BUG_ON(new_start > new_end); | |
605 | ||
606 | /* | |
607 | * ensure there are no vmas between where we want to go | |
608 | * and where we are | |
609 | */ | |
610 | if (vma != find_vma(mm, new_start)) | |
611 | return -EFAULT; | |
612 | ||
613 | /* | |
614 | * cover the whole range: [new_start, old_end) | |
615 | */ | |
616 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) | |
617 | return -ENOMEM; | |
618 | ||
619 | /* | |
620 | * move the page tables downwards, on failure we rely on | |
621 | * process cleanup to remove whatever mess we made. | |
622 | */ | |
623 | if (length != move_page_tables(vma, old_start, | |
624 | vma, new_start, length, false)) | |
625 | return -ENOMEM; | |
626 | ||
627 | lru_add_drain(); | |
628 | tlb_gather_mmu(&tlb, mm, old_start, old_end); | |
629 | if (new_end > old_start) { | |
630 | /* | |
631 | * when the old and new regions overlap clear from new_end. | |
632 | */ | |
633 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
634 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
635 | } else { | |
636 | /* | |
637 | * otherwise, clean from old_start; this is done to not touch | |
638 | * the address space in [new_end, old_start) some architectures | |
639 | * have constraints on va-space that make this illegal (IA64) - | |
640 | * for the others its just a little faster. | |
641 | */ | |
642 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
643 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); | |
644 | } | |
645 | tlb_finish_mmu(&tlb, old_start, old_end); | |
646 | ||
647 | /* | |
648 | * Shrink the vma to just the new range. Always succeeds. | |
649 | */ | |
650 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
651 | ||
652 | return 0; | |
653 | } | |
654 | ||
655 | /* | |
656 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
657 | * the stack is optionally relocated, and some extra space is added. | |
658 | */ | |
659 | int setup_arg_pages(struct linux_binprm *bprm, | |
660 | unsigned long stack_top, | |
661 | int executable_stack) | |
662 | { | |
663 | unsigned long ret; | |
664 | unsigned long stack_shift; | |
665 | struct mm_struct *mm = current->mm; | |
666 | struct vm_area_struct *vma = bprm->vma; | |
667 | struct vm_area_struct *prev = NULL; | |
668 | unsigned long vm_flags; | |
669 | unsigned long stack_base; | |
670 | unsigned long stack_size; | |
671 | unsigned long stack_expand; | |
672 | unsigned long rlim_stack; | |
673 | ||
674 | #ifdef CONFIG_STACK_GROWSUP | |
675 | /* Limit stack size */ | |
676 | stack_base = rlimit_max(RLIMIT_STACK); | |
677 | if (stack_base > STACK_SIZE_MAX) | |
678 | stack_base = STACK_SIZE_MAX; | |
679 | ||
680 | /* Add space for stack randomization. */ | |
681 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
682 | ||
683 | /* Make sure we didn't let the argument array grow too large. */ | |
684 | if (vma->vm_end - vma->vm_start > stack_base) | |
685 | return -ENOMEM; | |
686 | ||
687 | stack_base = PAGE_ALIGN(stack_top - stack_base); | |
688 | ||
689 | stack_shift = vma->vm_start - stack_base; | |
690 | mm->arg_start = bprm->p - stack_shift; | |
691 | bprm->p = vma->vm_end - stack_shift; | |
692 | #else | |
693 | stack_top = arch_align_stack(stack_top); | |
694 | stack_top = PAGE_ALIGN(stack_top); | |
695 | ||
696 | if (unlikely(stack_top < mmap_min_addr) || | |
697 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
698 | return -ENOMEM; | |
699 | ||
700 | stack_shift = vma->vm_end - stack_top; | |
701 | ||
702 | bprm->p -= stack_shift; | |
703 | mm->arg_start = bprm->p; | |
704 | #endif | |
705 | ||
706 | if (bprm->loader) | |
707 | bprm->loader -= stack_shift; | |
708 | bprm->exec -= stack_shift; | |
709 | ||
710 | if (down_write_killable(&mm->mmap_sem)) | |
711 | return -EINTR; | |
712 | ||
713 | vm_flags = VM_STACK_FLAGS; | |
714 | ||
715 | /* | |
716 | * Adjust stack execute permissions; explicitly enable for | |
717 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
718 | * (arch default) otherwise. | |
719 | */ | |
720 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
721 | vm_flags |= VM_EXEC; | |
722 | else if (executable_stack == EXSTACK_DISABLE_X) | |
723 | vm_flags &= ~VM_EXEC; | |
724 | vm_flags |= mm->def_flags; | |
725 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; | |
726 | ||
727 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
728 | vm_flags); | |
729 | if (ret) | |
730 | goto out_unlock; | |
731 | BUG_ON(prev != vma); | |
732 | ||
733 | /* Move stack pages down in memory. */ | |
734 | if (stack_shift) { | |
735 | ret = shift_arg_pages(vma, stack_shift); | |
736 | if (ret) | |
737 | goto out_unlock; | |
738 | } | |
739 | ||
740 | /* mprotect_fixup is overkill to remove the temporary stack flags */ | |
741 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
742 | ||
743 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ | |
744 | stack_size = vma->vm_end - vma->vm_start; | |
745 | /* | |
746 | * Align this down to a page boundary as expand_stack | |
747 | * will align it up. | |
748 | */ | |
749 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
750 | #ifdef CONFIG_STACK_GROWSUP | |
751 | if (stack_size + stack_expand > rlim_stack) | |
752 | stack_base = vma->vm_start + rlim_stack; | |
753 | else | |
754 | stack_base = vma->vm_end + stack_expand; | |
755 | #else | |
756 | if (stack_size + stack_expand > rlim_stack) | |
757 | stack_base = vma->vm_end - rlim_stack; | |
758 | else | |
759 | stack_base = vma->vm_start - stack_expand; | |
760 | #endif | |
761 | current->mm->start_stack = bprm->p; | |
762 | ret = expand_stack(vma, stack_base); | |
763 | if (ret) | |
764 | ret = -EFAULT; | |
765 | ||
766 | out_unlock: | |
767 | up_write(&mm->mmap_sem); | |
768 | return ret; | |
769 | } | |
770 | EXPORT_SYMBOL(setup_arg_pages); | |
771 | ||
772 | #else | |
773 | ||
774 | /* | |
775 | * Transfer the program arguments and environment from the holding pages | |
776 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
777 | */ | |
778 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
779 | unsigned long *sp_location) | |
780 | { | |
781 | unsigned long index, stop, sp; | |
782 | int ret = 0; | |
783 | ||
784 | stop = bprm->p >> PAGE_SHIFT; | |
785 | sp = *sp_location; | |
786 | ||
787 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
788 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
789 | char *src = kmap(bprm->page[index]) + offset; | |
790 | sp -= PAGE_SIZE - offset; | |
791 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
792 | ret = -EFAULT; | |
793 | kunmap(bprm->page[index]); | |
794 | if (ret) | |
795 | goto out; | |
796 | } | |
797 | ||
798 | *sp_location = sp; | |
799 | ||
800 | out: | |
801 | return ret; | |
802 | } | |
803 | EXPORT_SYMBOL(transfer_args_to_stack); | |
804 | ||
805 | #endif /* CONFIG_MMU */ | |
806 | ||
807 | static struct file *do_open_execat(int fd, struct filename *name, int flags) | |
808 | { | |
809 | struct file *file; | |
810 | int err; | |
811 | struct open_flags open_exec_flags = { | |
812 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
813 | .acc_mode = MAY_EXEC, | |
814 | .intent = LOOKUP_OPEN, | |
815 | .lookup_flags = LOOKUP_FOLLOW, | |
816 | }; | |
817 | ||
818 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) | |
819 | return ERR_PTR(-EINVAL); | |
820 | if (flags & AT_SYMLINK_NOFOLLOW) | |
821 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
822 | if (flags & AT_EMPTY_PATH) | |
823 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
824 | ||
825 | file = do_filp_open(fd, name, &open_exec_flags); | |
826 | if (IS_ERR(file)) | |
827 | goto out; | |
828 | ||
829 | err = -EACCES; | |
830 | if (!S_ISREG(file_inode(file)->i_mode)) | |
831 | goto exit; | |
832 | ||
833 | if (path_noexec(&file->f_path)) | |
834 | goto exit; | |
835 | ||
836 | err = deny_write_access(file); | |
837 | if (err) | |
838 | goto exit; | |
839 | ||
840 | if (name->name[0] != '\0') | |
841 | fsnotify_open(file); | |
842 | ||
843 | out: | |
844 | return file; | |
845 | ||
846 | exit: | |
847 | fput(file); | |
848 | return ERR_PTR(err); | |
849 | } | |
850 | ||
851 | struct file *open_exec(const char *name) | |
852 | { | |
853 | struct filename *filename = getname_kernel(name); | |
854 | struct file *f = ERR_CAST(filename); | |
855 | ||
856 | if (!IS_ERR(filename)) { | |
857 | f = do_open_execat(AT_FDCWD, filename, 0); | |
858 | putname(filename); | |
859 | } | |
860 | return f; | |
861 | } | |
862 | EXPORT_SYMBOL(open_exec); | |
863 | ||
864 | int kernel_read(struct file *file, loff_t offset, | |
865 | char *addr, unsigned long count) | |
866 | { | |
867 | mm_segment_t old_fs; | |
868 | loff_t pos = offset; | |
869 | int result; | |
870 | ||
871 | old_fs = get_fs(); | |
872 | set_fs(get_ds()); | |
873 | /* The cast to a user pointer is valid due to the set_fs() */ | |
874 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
875 | set_fs(old_fs); | |
876 | return result; | |
877 | } | |
878 | ||
879 | EXPORT_SYMBOL(kernel_read); | |
880 | ||
881 | int kernel_read_file(struct file *file, void **buf, loff_t *size, | |
882 | loff_t max_size, enum kernel_read_file_id id) | |
883 | { | |
884 | loff_t i_size, pos; | |
885 | ssize_t bytes = 0; | |
886 | int ret; | |
887 | ||
888 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
889 | return -EINVAL; | |
890 | ||
891 | ret = security_kernel_read_file(file, id); | |
892 | if (ret) | |
893 | return ret; | |
894 | ||
895 | ret = deny_write_access(file); | |
896 | if (ret) | |
897 | return ret; | |
898 | ||
899 | i_size = i_size_read(file_inode(file)); | |
900 | if (max_size > 0 && i_size > max_size) { | |
901 | ret = -EFBIG; | |
902 | goto out; | |
903 | } | |
904 | if (i_size <= 0) { | |
905 | ret = -EINVAL; | |
906 | goto out; | |
907 | } | |
908 | ||
909 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) | |
910 | *buf = vmalloc(i_size); | |
911 | if (!*buf) { | |
912 | ret = -ENOMEM; | |
913 | goto out; | |
914 | } | |
915 | ||
916 | pos = 0; | |
917 | while (pos < i_size) { | |
918 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
919 | i_size - pos); | |
920 | if (bytes < 0) { | |
921 | ret = bytes; | |
922 | goto out; | |
923 | } | |
924 | ||
925 | if (bytes == 0) | |
926 | break; | |
927 | pos += bytes; | |
928 | } | |
929 | ||
930 | if (pos != i_size) { | |
931 | ret = -EIO; | |
932 | goto out_free; | |
933 | } | |
934 | ||
935 | ret = security_kernel_post_read_file(file, *buf, i_size, id); | |
936 | if (!ret) | |
937 | *size = pos; | |
938 | ||
939 | out_free: | |
940 | if (ret < 0) { | |
941 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { | |
942 | vfree(*buf); | |
943 | *buf = NULL; | |
944 | } | |
945 | } | |
946 | ||
947 | out: | |
948 | allow_write_access(file); | |
949 | return ret; | |
950 | } | |
951 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
952 | ||
953 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, | |
954 | loff_t max_size, enum kernel_read_file_id id) | |
955 | { | |
956 | struct file *file; | |
957 | int ret; | |
958 | ||
959 | if (!path || !*path) | |
960 | return -EINVAL; | |
961 | ||
962 | file = filp_open(path, O_RDONLY, 0); | |
963 | if (IS_ERR(file)) | |
964 | return PTR_ERR(file); | |
965 | ||
966 | ret = kernel_read_file(file, buf, size, max_size, id); | |
967 | fput(file); | |
968 | return ret; | |
969 | } | |
970 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
971 | ||
972 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, | |
973 | enum kernel_read_file_id id) | |
974 | { | |
975 | struct fd f = fdget(fd); | |
976 | int ret = -EBADF; | |
977 | ||
978 | if (!f.file) | |
979 | goto out; | |
980 | ||
981 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
982 | out: | |
983 | fdput(f); | |
984 | return ret; | |
985 | } | |
986 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
987 | ||
988 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) | |
989 | { | |
990 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); | |
991 | if (res > 0) | |
992 | flush_icache_range(addr, addr + len); | |
993 | return res; | |
994 | } | |
995 | EXPORT_SYMBOL(read_code); | |
996 | ||
997 | static int exec_mmap(struct mm_struct *mm) | |
998 | { | |
999 | struct task_struct *tsk; | |
1000 | struct mm_struct *old_mm, *active_mm; | |
1001 | ||
1002 | /* Notify parent that we're no longer interested in the old VM */ | |
1003 | tsk = current; | |
1004 | old_mm = current->mm; | |
1005 | mm_release(tsk, old_mm); | |
1006 | ||
1007 | if (old_mm) { | |
1008 | sync_mm_rss(old_mm); | |
1009 | /* | |
1010 | * Make sure that if there is a core dump in progress | |
1011 | * for the old mm, we get out and die instead of going | |
1012 | * through with the exec. We must hold mmap_sem around | |
1013 | * checking core_state and changing tsk->mm. | |
1014 | */ | |
1015 | down_read(&old_mm->mmap_sem); | |
1016 | if (unlikely(old_mm->core_state)) { | |
1017 | up_read(&old_mm->mmap_sem); | |
1018 | return -EINTR; | |
1019 | } | |
1020 | } | |
1021 | task_lock(tsk); | |
1022 | active_mm = tsk->active_mm; | |
1023 | tsk->mm = mm; | |
1024 | tsk->active_mm = mm; | |
1025 | activate_mm(active_mm, mm); | |
1026 | tsk->mm->vmacache_seqnum = 0; | |
1027 | vmacache_flush(tsk); | |
1028 | task_unlock(tsk); | |
1029 | if (old_mm) { | |
1030 | up_read(&old_mm->mmap_sem); | |
1031 | BUG_ON(active_mm != old_mm); | |
1032 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); | |
1033 | mm_update_next_owner(old_mm); | |
1034 | mmput(old_mm); | |
1035 | return 0; | |
1036 | } | |
1037 | mmdrop(active_mm); | |
1038 | return 0; | |
1039 | } | |
1040 | ||
1041 | /* | |
1042 | * This function makes sure the current process has its own signal table, | |
1043 | * so that flush_signal_handlers can later reset the handlers without | |
1044 | * disturbing other processes. (Other processes might share the signal | |
1045 | * table via the CLONE_SIGHAND option to clone().) | |
1046 | */ | |
1047 | static int de_thread(struct task_struct *tsk) | |
1048 | { | |
1049 | struct signal_struct *sig = tsk->signal; | |
1050 | struct sighand_struct *oldsighand = tsk->sighand; | |
1051 | spinlock_t *lock = &oldsighand->siglock; | |
1052 | ||
1053 | if (thread_group_empty(tsk)) | |
1054 | goto no_thread_group; | |
1055 | ||
1056 | /* | |
1057 | * Kill all other threads in the thread group. | |
1058 | */ | |
1059 | spin_lock_irq(lock); | |
1060 | if (signal_group_exit(sig)) { | |
1061 | /* | |
1062 | * Another group action in progress, just | |
1063 | * return so that the signal is processed. | |
1064 | */ | |
1065 | spin_unlock_irq(lock); | |
1066 | return -EAGAIN; | |
1067 | } | |
1068 | ||
1069 | sig->group_exit_task = tsk; | |
1070 | sig->notify_count = zap_other_threads(tsk); | |
1071 | if (!thread_group_leader(tsk)) | |
1072 | sig->notify_count--; | |
1073 | ||
1074 | while (sig->notify_count) { | |
1075 | __set_current_state(TASK_KILLABLE); | |
1076 | spin_unlock_irq(lock); | |
1077 | schedule(); | |
1078 | if (unlikely(__fatal_signal_pending(tsk))) | |
1079 | goto killed; | |
1080 | spin_lock_irq(lock); | |
1081 | } | |
1082 | spin_unlock_irq(lock); | |
1083 | ||
1084 | /* | |
1085 | * At this point all other threads have exited, all we have to | |
1086 | * do is to wait for the thread group leader to become inactive, | |
1087 | * and to assume its PID: | |
1088 | */ | |
1089 | if (!thread_group_leader(tsk)) { | |
1090 | struct task_struct *leader = tsk->group_leader; | |
1091 | ||
1092 | for (;;) { | |
1093 | cgroup_threadgroup_change_begin(tsk); | |
1094 | write_lock_irq(&tasklist_lock); | |
1095 | /* | |
1096 | * Do this under tasklist_lock to ensure that | |
1097 | * exit_notify() can't miss ->group_exit_task | |
1098 | */ | |
1099 | sig->notify_count = -1; | |
1100 | if (likely(leader->exit_state)) | |
1101 | break; | |
1102 | __set_current_state(TASK_KILLABLE); | |
1103 | write_unlock_irq(&tasklist_lock); | |
1104 | cgroup_threadgroup_change_end(tsk); | |
1105 | schedule(); | |
1106 | if (unlikely(__fatal_signal_pending(tsk))) | |
1107 | goto killed; | |
1108 | } | |
1109 | ||
1110 | /* | |
1111 | * The only record we have of the real-time age of a | |
1112 | * process, regardless of execs it's done, is start_time. | |
1113 | * All the past CPU time is accumulated in signal_struct | |
1114 | * from sister threads now dead. But in this non-leader | |
1115 | * exec, nothing survives from the original leader thread, | |
1116 | * whose birth marks the true age of this process now. | |
1117 | * When we take on its identity by switching to its PID, we | |
1118 | * also take its birthdate (always earlier than our own). | |
1119 | */ | |
1120 | tsk->start_time = leader->start_time; | |
1121 | tsk->real_start_time = leader->real_start_time; | |
1122 | ||
1123 | BUG_ON(!same_thread_group(leader, tsk)); | |
1124 | BUG_ON(has_group_leader_pid(tsk)); | |
1125 | /* | |
1126 | * An exec() starts a new thread group with the | |
1127 | * TGID of the previous thread group. Rehash the | |
1128 | * two threads with a switched PID, and release | |
1129 | * the former thread group leader: | |
1130 | */ | |
1131 | ||
1132 | /* Become a process group leader with the old leader's pid. | |
1133 | * The old leader becomes a thread of the this thread group. | |
1134 | * Note: The old leader also uses this pid until release_task | |
1135 | * is called. Odd but simple and correct. | |
1136 | */ | |
1137 | tsk->pid = leader->pid; | |
1138 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); | |
1139 | transfer_pid(leader, tsk, PIDTYPE_PGID); | |
1140 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
1141 | ||
1142 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1143 | list_replace_init(&leader->sibling, &tsk->sibling); | |
1144 | ||
1145 | tsk->group_leader = tsk; | |
1146 | leader->group_leader = tsk; | |
1147 | ||
1148 | tsk->exit_signal = SIGCHLD; | |
1149 | leader->exit_signal = -1; | |
1150 | ||
1151 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1152 | leader->exit_state = EXIT_DEAD; | |
1153 | ||
1154 | /* | |
1155 | * We are going to release_task()->ptrace_unlink() silently, | |
1156 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1157 | * the tracer wont't block again waiting for this thread. | |
1158 | */ | |
1159 | if (unlikely(leader->ptrace)) | |
1160 | __wake_up_parent(leader, leader->parent); | |
1161 | write_unlock_irq(&tasklist_lock); | |
1162 | cgroup_threadgroup_change_end(tsk); | |
1163 | ||
1164 | release_task(leader); | |
1165 | } | |
1166 | ||
1167 | sig->group_exit_task = NULL; | |
1168 | sig->notify_count = 0; | |
1169 | ||
1170 | no_thread_group: | |
1171 | /* we have changed execution domain */ | |
1172 | tsk->exit_signal = SIGCHLD; | |
1173 | ||
1174 | #ifdef CONFIG_POSIX_TIMERS | |
1175 | exit_itimers(sig); | |
1176 | flush_itimer_signals(); | |
1177 | #endif | |
1178 | ||
1179 | if (atomic_read(&oldsighand->count) != 1) { | |
1180 | struct sighand_struct *newsighand; | |
1181 | /* | |
1182 | * This ->sighand is shared with the CLONE_SIGHAND | |
1183 | * but not CLONE_THREAD task, switch to the new one. | |
1184 | */ | |
1185 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
1186 | if (!newsighand) | |
1187 | return -ENOMEM; | |
1188 | ||
1189 | atomic_set(&newsighand->count, 1); | |
1190 | memcpy(newsighand->action, oldsighand->action, | |
1191 | sizeof(newsighand->action)); | |
1192 | ||
1193 | write_lock_irq(&tasklist_lock); | |
1194 | spin_lock(&oldsighand->siglock); | |
1195 | rcu_assign_pointer(tsk->sighand, newsighand); | |
1196 | spin_unlock(&oldsighand->siglock); | |
1197 | write_unlock_irq(&tasklist_lock); | |
1198 | ||
1199 | __cleanup_sighand(oldsighand); | |
1200 | } | |
1201 | ||
1202 | BUG_ON(!thread_group_leader(tsk)); | |
1203 | return 0; | |
1204 | ||
1205 | killed: | |
1206 | /* protects against exit_notify() and __exit_signal() */ | |
1207 | read_lock(&tasklist_lock); | |
1208 | sig->group_exit_task = NULL; | |
1209 | sig->notify_count = 0; | |
1210 | read_unlock(&tasklist_lock); | |
1211 | return -EAGAIN; | |
1212 | } | |
1213 | ||
1214 | char *get_task_comm(char *buf, struct task_struct *tsk) | |
1215 | { | |
1216 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1217 | task_lock(tsk); | |
1218 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1219 | task_unlock(tsk); | |
1220 | return buf; | |
1221 | } | |
1222 | EXPORT_SYMBOL_GPL(get_task_comm); | |
1223 | ||
1224 | /* | |
1225 | * These functions flushes out all traces of the currently running executable | |
1226 | * so that a new one can be started | |
1227 | */ | |
1228 | ||
1229 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) | |
1230 | { | |
1231 | task_lock(tsk); | |
1232 | trace_task_rename(tsk, buf); | |
1233 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
1234 | task_unlock(tsk); | |
1235 | perf_event_comm(tsk, exec); | |
1236 | } | |
1237 | ||
1238 | int flush_old_exec(struct linux_binprm * bprm) | |
1239 | { | |
1240 | int retval; | |
1241 | ||
1242 | /* | |
1243 | * Make sure we have a private signal table and that | |
1244 | * we are unassociated from the previous thread group. | |
1245 | */ | |
1246 | retval = de_thread(current); | |
1247 | if (retval) | |
1248 | goto out; | |
1249 | ||
1250 | /* | |
1251 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1252 | * not visibile until then. This also enables the update | |
1253 | * to be lockless. | |
1254 | */ | |
1255 | set_mm_exe_file(bprm->mm, bprm->file); | |
1256 | ||
1257 | /* | |
1258 | * Release all of the old mmap stuff | |
1259 | */ | |
1260 | acct_arg_size(bprm, 0); | |
1261 | retval = exec_mmap(bprm->mm); | |
1262 | if (retval) | |
1263 | goto out; | |
1264 | ||
1265 | bprm->mm = NULL; /* We're using it now */ | |
1266 | ||
1267 | set_fs(USER_DS); | |
1268 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | | |
1269 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
1270 | flush_thread(); | |
1271 | current->personality &= ~bprm->per_clear; | |
1272 | ||
1273 | /* | |
1274 | * We have to apply CLOEXEC before we change whether the process is | |
1275 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1276 | * trying to access the should-be-closed file descriptors of a process | |
1277 | * undergoing exec(2). | |
1278 | */ | |
1279 | do_close_on_exec(current->files); | |
1280 | return 0; | |
1281 | ||
1282 | out: | |
1283 | return retval; | |
1284 | } | |
1285 | EXPORT_SYMBOL(flush_old_exec); | |
1286 | ||
1287 | void would_dump(struct linux_binprm *bprm, struct file *file) | |
1288 | { | |
1289 | struct inode *inode = file_inode(file); | |
1290 | if (inode_permission(inode, MAY_READ) < 0) { | |
1291 | struct user_namespace *old, *user_ns; | |
1292 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; | |
1293 | ||
1294 | /* Ensure mm->user_ns contains the executable */ | |
1295 | user_ns = old = bprm->mm->user_ns; | |
1296 | while ((user_ns != &init_user_ns) && | |
1297 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1298 | user_ns = user_ns->parent; | |
1299 | ||
1300 | if (old != user_ns) { | |
1301 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1302 | put_user_ns(old); | |
1303 | } | |
1304 | } | |
1305 | } | |
1306 | EXPORT_SYMBOL(would_dump); | |
1307 | ||
1308 | void setup_new_exec(struct linux_binprm * bprm) | |
1309 | { | |
1310 | arch_pick_mmap_layout(current->mm); | |
1311 | ||
1312 | /* This is the point of no return */ | |
1313 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1314 | ||
1315 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) | |
1316 | set_dumpable(current->mm, SUID_DUMP_USER); | |
1317 | else | |
1318 | set_dumpable(current->mm, suid_dumpable); | |
1319 | ||
1320 | perf_event_exec(); | |
1321 | __set_task_comm(current, kbasename(bprm->filename), true); | |
1322 | ||
1323 | /* Set the new mm task size. We have to do that late because it may | |
1324 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1325 | * some architectures like powerpc | |
1326 | */ | |
1327 | current->mm->task_size = TASK_SIZE; | |
1328 | ||
1329 | /* install the new credentials */ | |
1330 | if (!uid_eq(bprm->cred->uid, current_euid()) || | |
1331 | !gid_eq(bprm->cred->gid, current_egid())) { | |
1332 | current->pdeath_signal = 0; | |
1333 | } else { | |
1334 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) | |
1335 | set_dumpable(current->mm, suid_dumpable); | |
1336 | } | |
1337 | ||
1338 | /* An exec changes our domain. We are no longer part of the thread | |
1339 | group */ | |
1340 | current->self_exec_id++; | |
1341 | flush_signal_handlers(current, 0); | |
1342 | } | |
1343 | EXPORT_SYMBOL(setup_new_exec); | |
1344 | ||
1345 | /* | |
1346 | * Prepare credentials and lock ->cred_guard_mutex. | |
1347 | * install_exec_creds() commits the new creds and drops the lock. | |
1348 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1349 | * and unlock. | |
1350 | */ | |
1351 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1352 | { | |
1353 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) | |
1354 | return -ERESTARTNOINTR; | |
1355 | ||
1356 | bprm->cred = prepare_exec_creds(); | |
1357 | if (likely(bprm->cred)) | |
1358 | return 0; | |
1359 | ||
1360 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1361 | return -ENOMEM; | |
1362 | } | |
1363 | ||
1364 | static void free_bprm(struct linux_binprm *bprm) | |
1365 | { | |
1366 | free_arg_pages(bprm); | |
1367 | if (bprm->cred) { | |
1368 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1369 | abort_creds(bprm->cred); | |
1370 | } | |
1371 | if (bprm->file) { | |
1372 | allow_write_access(bprm->file); | |
1373 | fput(bprm->file); | |
1374 | } | |
1375 | /* If a binfmt changed the interp, free it. */ | |
1376 | if (bprm->interp != bprm->filename) | |
1377 | kfree(bprm->interp); | |
1378 | kfree(bprm); | |
1379 | } | |
1380 | ||
1381 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) | |
1382 | { | |
1383 | /* If a binfmt changed the interp, free it first. */ | |
1384 | if (bprm->interp != bprm->filename) | |
1385 | kfree(bprm->interp); | |
1386 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1387 | if (!bprm->interp) | |
1388 | return -ENOMEM; | |
1389 | return 0; | |
1390 | } | |
1391 | EXPORT_SYMBOL(bprm_change_interp); | |
1392 | ||
1393 | /* | |
1394 | * install the new credentials for this executable | |
1395 | */ | |
1396 | void install_exec_creds(struct linux_binprm *bprm) | |
1397 | { | |
1398 | security_bprm_committing_creds(bprm); | |
1399 | ||
1400 | commit_creds(bprm->cred); | |
1401 | bprm->cred = NULL; | |
1402 | ||
1403 | /* | |
1404 | * Disable monitoring for regular users | |
1405 | * when executing setuid binaries. Must | |
1406 | * wait until new credentials are committed | |
1407 | * by commit_creds() above | |
1408 | */ | |
1409 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1410 | perf_event_exit_task(current); | |
1411 | /* | |
1412 | * cred_guard_mutex must be held at least to this point to prevent | |
1413 | * ptrace_attach() from altering our determination of the task's | |
1414 | * credentials; any time after this it may be unlocked. | |
1415 | */ | |
1416 | security_bprm_committed_creds(bprm); | |
1417 | mutex_unlock(¤t->signal->cred_guard_mutex); | |
1418 | } | |
1419 | EXPORT_SYMBOL(install_exec_creds); | |
1420 | ||
1421 | /* | |
1422 | * determine how safe it is to execute the proposed program | |
1423 | * - the caller must hold ->cred_guard_mutex to protect against | |
1424 | * PTRACE_ATTACH or seccomp thread-sync | |
1425 | */ | |
1426 | static void check_unsafe_exec(struct linux_binprm *bprm) | |
1427 | { | |
1428 | struct task_struct *p = current, *t; | |
1429 | unsigned n_fs; | |
1430 | ||
1431 | if (p->ptrace) | |
1432 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
1433 | ||
1434 | /* | |
1435 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1436 | * mess up. | |
1437 | */ | |
1438 | if (task_no_new_privs(current)) | |
1439 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; | |
1440 | ||
1441 | t = p; | |
1442 | n_fs = 1; | |
1443 | spin_lock(&p->fs->lock); | |
1444 | rcu_read_lock(); | |
1445 | while_each_thread(p, t) { | |
1446 | if (t->fs == p->fs) | |
1447 | n_fs++; | |
1448 | } | |
1449 | rcu_read_unlock(); | |
1450 | ||
1451 | if (p->fs->users > n_fs) | |
1452 | bprm->unsafe |= LSM_UNSAFE_SHARE; | |
1453 | else | |
1454 | p->fs->in_exec = 1; | |
1455 | spin_unlock(&p->fs->lock); | |
1456 | } | |
1457 | ||
1458 | static void bprm_fill_uid(struct linux_binprm *bprm) | |
1459 | { | |
1460 | struct inode *inode; | |
1461 | unsigned int mode; | |
1462 | kuid_t uid; | |
1463 | kgid_t gid; | |
1464 | ||
1465 | /* | |
1466 | * Since this can be called multiple times (via prepare_binprm), | |
1467 | * we must clear any previous work done when setting set[ug]id | |
1468 | * bits from any earlier bprm->file uses (for example when run | |
1469 | * first for a setuid script then again for its interpreter). | |
1470 | */ | |
1471 | bprm->cred->euid = current_euid(); | |
1472 | bprm->cred->egid = current_egid(); | |
1473 | ||
1474 | if (!mnt_may_suid(bprm->file->f_path.mnt)) | |
1475 | return; | |
1476 | ||
1477 | if (task_no_new_privs(current)) | |
1478 | return; | |
1479 | ||
1480 | inode = bprm->file->f_path.dentry->d_inode; | |
1481 | mode = READ_ONCE(inode->i_mode); | |
1482 | if (!(mode & (S_ISUID|S_ISGID))) | |
1483 | return; | |
1484 | ||
1485 | /* Be careful if suid/sgid is set */ | |
1486 | inode_lock(inode); | |
1487 | ||
1488 | /* reload atomically mode/uid/gid now that lock held */ | |
1489 | mode = inode->i_mode; | |
1490 | uid = inode->i_uid; | |
1491 | gid = inode->i_gid; | |
1492 | inode_unlock(inode); | |
1493 | ||
1494 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1495 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1496 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1497 | return; | |
1498 | ||
1499 | if (mode & S_ISUID) { | |
1500 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1501 | bprm->cred->euid = uid; | |
1502 | } | |
1503 | ||
1504 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1505 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1506 | bprm->cred->egid = gid; | |
1507 | } | |
1508 | } | |
1509 | ||
1510 | /* | |
1511 | * Fill the binprm structure from the inode. | |
1512 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1513 | * | |
1514 | * This may be called multiple times for binary chains (scripts for example). | |
1515 | */ | |
1516 | int prepare_binprm(struct linux_binprm *bprm) | |
1517 | { | |
1518 | int retval; | |
1519 | ||
1520 | bprm_fill_uid(bprm); | |
1521 | ||
1522 | /* fill in binprm security blob */ | |
1523 | retval = security_bprm_set_creds(bprm); | |
1524 | if (retval) | |
1525 | return retval; | |
1526 | bprm->cred_prepared = 1; | |
1527 | ||
1528 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); | |
1529 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1530 | } | |
1531 | ||
1532 | EXPORT_SYMBOL(prepare_binprm); | |
1533 | ||
1534 | /* | |
1535 | * Arguments are '\0' separated strings found at the location bprm->p | |
1536 | * points to; chop off the first by relocating brpm->p to right after | |
1537 | * the first '\0' encountered. | |
1538 | */ | |
1539 | int remove_arg_zero(struct linux_binprm *bprm) | |
1540 | { | |
1541 | int ret = 0; | |
1542 | unsigned long offset; | |
1543 | char *kaddr; | |
1544 | struct page *page; | |
1545 | ||
1546 | if (!bprm->argc) | |
1547 | return 0; | |
1548 | ||
1549 | do { | |
1550 | offset = bprm->p & ~PAGE_MASK; | |
1551 | page = get_arg_page(bprm, bprm->p, 0); | |
1552 | if (!page) { | |
1553 | ret = -EFAULT; | |
1554 | goto out; | |
1555 | } | |
1556 | kaddr = kmap_atomic(page); | |
1557 | ||
1558 | for (; offset < PAGE_SIZE && kaddr[offset]; | |
1559 | offset++, bprm->p++) | |
1560 | ; | |
1561 | ||
1562 | kunmap_atomic(kaddr); | |
1563 | put_arg_page(page); | |
1564 | } while (offset == PAGE_SIZE); | |
1565 | ||
1566 | bprm->p++; | |
1567 | bprm->argc--; | |
1568 | ret = 0; | |
1569 | ||
1570 | out: | |
1571 | return ret; | |
1572 | } | |
1573 | EXPORT_SYMBOL(remove_arg_zero); | |
1574 | ||
1575 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1576 | /* | |
1577 | * cycle the list of binary formats handler, until one recognizes the image | |
1578 | */ | |
1579 | int search_binary_handler(struct linux_binprm *bprm) | |
1580 | { | |
1581 | bool need_retry = IS_ENABLED(CONFIG_MODULES); | |
1582 | struct linux_binfmt *fmt; | |
1583 | int retval; | |
1584 | ||
1585 | /* This allows 4 levels of binfmt rewrites before failing hard. */ | |
1586 | if (bprm->recursion_depth > 5) | |
1587 | return -ELOOP; | |
1588 | ||
1589 | retval = security_bprm_check(bprm); | |
1590 | if (retval) | |
1591 | return retval; | |
1592 | ||
1593 | retval = -ENOENT; | |
1594 | retry: | |
1595 | read_lock(&binfmt_lock); | |
1596 | list_for_each_entry(fmt, &formats, lh) { | |
1597 | if (!try_module_get(fmt->module)) | |
1598 | continue; | |
1599 | read_unlock(&binfmt_lock); | |
1600 | bprm->recursion_depth++; | |
1601 | retval = fmt->load_binary(bprm); | |
1602 | read_lock(&binfmt_lock); | |
1603 | put_binfmt(fmt); | |
1604 | bprm->recursion_depth--; | |
1605 | if (retval < 0 && !bprm->mm) { | |
1606 | /* we got to flush_old_exec() and failed after it */ | |
1607 | read_unlock(&binfmt_lock); | |
1608 | force_sigsegv(SIGSEGV, current); | |
1609 | return retval; | |
1610 | } | |
1611 | if (retval != -ENOEXEC || !bprm->file) { | |
1612 | read_unlock(&binfmt_lock); | |
1613 | return retval; | |
1614 | } | |
1615 | } | |
1616 | read_unlock(&binfmt_lock); | |
1617 | ||
1618 | if (need_retry) { | |
1619 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && | |
1620 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1621 | return retval; | |
1622 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) | |
1623 | return retval; | |
1624 | need_retry = false; | |
1625 | goto retry; | |
1626 | } | |
1627 | ||
1628 | return retval; | |
1629 | } | |
1630 | EXPORT_SYMBOL(search_binary_handler); | |
1631 | ||
1632 | static int exec_binprm(struct linux_binprm *bprm) | |
1633 | { | |
1634 | pid_t old_pid, old_vpid; | |
1635 | int ret; | |
1636 | ||
1637 | /* Need to fetch pid before load_binary changes it */ | |
1638 | old_pid = current->pid; | |
1639 | rcu_read_lock(); | |
1640 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1641 | rcu_read_unlock(); | |
1642 | ||
1643 | ret = search_binary_handler(bprm); | |
1644 | if (ret >= 0) { | |
1645 | audit_bprm(bprm); | |
1646 | trace_sched_process_exec(current, old_pid, bprm); | |
1647 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
1648 | proc_exec_connector(current); | |
1649 | } | |
1650 | ||
1651 | return ret; | |
1652 | } | |
1653 | ||
1654 | /* | |
1655 | * sys_execve() executes a new program. | |
1656 | */ | |
1657 | static int do_execveat_common(int fd, struct filename *filename, | |
1658 | struct user_arg_ptr argv, | |
1659 | struct user_arg_ptr envp, | |
1660 | int flags) | |
1661 | { | |
1662 | char *pathbuf = NULL; | |
1663 | struct linux_binprm *bprm; | |
1664 | struct file *file; | |
1665 | struct files_struct *displaced; | |
1666 | int retval; | |
1667 | ||
1668 | if (IS_ERR(filename)) | |
1669 | return PTR_ERR(filename); | |
1670 | ||
1671 | /* | |
1672 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1673 | * set*uid() to execve() because too many poorly written programs | |
1674 | * don't check setuid() return code. Here we additionally recheck | |
1675 | * whether NPROC limit is still exceeded. | |
1676 | */ | |
1677 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
1678 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { | |
1679 | retval = -EAGAIN; | |
1680 | goto out_ret; | |
1681 | } | |
1682 | ||
1683 | /* We're below the limit (still or again), so we don't want to make | |
1684 | * further execve() calls fail. */ | |
1685 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1686 | ||
1687 | retval = unshare_files(&displaced); | |
1688 | if (retval) | |
1689 | goto out_ret; | |
1690 | ||
1691 | retval = -ENOMEM; | |
1692 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); | |
1693 | if (!bprm) | |
1694 | goto out_files; | |
1695 | ||
1696 | retval = prepare_bprm_creds(bprm); | |
1697 | if (retval) | |
1698 | goto out_free; | |
1699 | ||
1700 | check_unsafe_exec(bprm); | |
1701 | current->in_execve = 1; | |
1702 | ||
1703 | file = do_open_execat(fd, filename, flags); | |
1704 | retval = PTR_ERR(file); | |
1705 | if (IS_ERR(file)) | |
1706 | goto out_unmark; | |
1707 | ||
1708 | sched_exec(); | |
1709 | ||
1710 | bprm->file = file; | |
1711 | if (fd == AT_FDCWD || filename->name[0] == '/') { | |
1712 | bprm->filename = filename->name; | |
1713 | } else { | |
1714 | if (filename->name[0] == '\0') | |
1715 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1716 | else | |
1717 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1718 | fd, filename->name); | |
1719 | if (!pathbuf) { | |
1720 | retval = -ENOMEM; | |
1721 | goto out_unmark; | |
1722 | } | |
1723 | /* | |
1724 | * Record that a name derived from an O_CLOEXEC fd will be | |
1725 | * inaccessible after exec. Relies on having exclusive access to | |
1726 | * current->files (due to unshare_files above). | |
1727 | */ | |
1728 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1729 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1730 | bprm->filename = pathbuf; | |
1731 | } | |
1732 | bprm->interp = bprm->filename; | |
1733 | ||
1734 | retval = bprm_mm_init(bprm); | |
1735 | if (retval) | |
1736 | goto out_unmark; | |
1737 | ||
1738 | bprm->argc = count(argv, MAX_ARG_STRINGS); | |
1739 | if ((retval = bprm->argc) < 0) | |
1740 | goto out; | |
1741 | ||
1742 | bprm->envc = count(envp, MAX_ARG_STRINGS); | |
1743 | if ((retval = bprm->envc) < 0) | |
1744 | goto out; | |
1745 | ||
1746 | retval = prepare_binprm(bprm); | |
1747 | if (retval < 0) | |
1748 | goto out; | |
1749 | ||
1750 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1751 | if (retval < 0) | |
1752 | goto out; | |
1753 | ||
1754 | bprm->exec = bprm->p; | |
1755 | retval = copy_strings(bprm->envc, envp, bprm); | |
1756 | if (retval < 0) | |
1757 | goto out; | |
1758 | ||
1759 | retval = copy_strings(bprm->argc, argv, bprm); | |
1760 | if (retval < 0) | |
1761 | goto out; | |
1762 | ||
1763 | would_dump(bprm, bprm->file); | |
1764 | ||
1765 | retval = exec_binprm(bprm); | |
1766 | if (retval < 0) | |
1767 | goto out; | |
1768 | ||
1769 | /* execve succeeded */ | |
1770 | current->fs->in_exec = 0; | |
1771 | current->in_execve = 0; | |
1772 | acct_update_integrals(current); | |
1773 | task_numa_free(current); | |
1774 | free_bprm(bprm); | |
1775 | kfree(pathbuf); | |
1776 | putname(filename); | |
1777 | if (displaced) | |
1778 | put_files_struct(displaced); | |
1779 | return retval; | |
1780 | ||
1781 | out: | |
1782 | if (bprm->mm) { | |
1783 | acct_arg_size(bprm, 0); | |
1784 | mmput(bprm->mm); | |
1785 | } | |
1786 | ||
1787 | out_unmark: | |
1788 | current->fs->in_exec = 0; | |
1789 | current->in_execve = 0; | |
1790 | ||
1791 | out_free: | |
1792 | free_bprm(bprm); | |
1793 | kfree(pathbuf); | |
1794 | ||
1795 | out_files: | |
1796 | if (displaced) | |
1797 | reset_files_struct(displaced); | |
1798 | out_ret: | |
1799 | putname(filename); | |
1800 | return retval; | |
1801 | } | |
1802 | ||
1803 | int do_execve(struct filename *filename, | |
1804 | const char __user *const __user *__argv, | |
1805 | const char __user *const __user *__envp) | |
1806 | { | |
1807 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1808 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1809 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1810 | } | |
1811 | ||
1812 | int do_execveat(int fd, struct filename *filename, | |
1813 | const char __user *const __user *__argv, | |
1814 | const char __user *const __user *__envp, | |
1815 | int flags) | |
1816 | { | |
1817 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1818 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1819 | ||
1820 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1821 | } | |
1822 | ||
1823 | #ifdef CONFIG_COMPAT | |
1824 | static int compat_do_execve(struct filename *filename, | |
1825 | const compat_uptr_t __user *__argv, | |
1826 | const compat_uptr_t __user *__envp) | |
1827 | { | |
1828 | struct user_arg_ptr argv = { | |
1829 | .is_compat = true, | |
1830 | .ptr.compat = __argv, | |
1831 | }; | |
1832 | struct user_arg_ptr envp = { | |
1833 | .is_compat = true, | |
1834 | .ptr.compat = __envp, | |
1835 | }; | |
1836 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); | |
1837 | } | |
1838 | ||
1839 | static int compat_do_execveat(int fd, struct filename *filename, | |
1840 | const compat_uptr_t __user *__argv, | |
1841 | const compat_uptr_t __user *__envp, | |
1842 | int flags) | |
1843 | { | |
1844 | struct user_arg_ptr argv = { | |
1845 | .is_compat = true, | |
1846 | .ptr.compat = __argv, | |
1847 | }; | |
1848 | struct user_arg_ptr envp = { | |
1849 | .is_compat = true, | |
1850 | .ptr.compat = __envp, | |
1851 | }; | |
1852 | return do_execveat_common(fd, filename, argv, envp, flags); | |
1853 | } | |
1854 | #endif | |
1855 | ||
1856 | void set_binfmt(struct linux_binfmt *new) | |
1857 | { | |
1858 | struct mm_struct *mm = current->mm; | |
1859 | ||
1860 | if (mm->binfmt) | |
1861 | module_put(mm->binfmt->module); | |
1862 | ||
1863 | mm->binfmt = new; | |
1864 | if (new) | |
1865 | __module_get(new->module); | |
1866 | } | |
1867 | EXPORT_SYMBOL(set_binfmt); | |
1868 | ||
1869 | /* | |
1870 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. | |
1871 | */ | |
1872 | void set_dumpable(struct mm_struct *mm, int value) | |
1873 | { | |
1874 | unsigned long old, new; | |
1875 | ||
1876 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) | |
1877 | return; | |
1878 | ||
1879 | do { | |
1880 | old = ACCESS_ONCE(mm->flags); | |
1881 | new = (old & ~MMF_DUMPABLE_MASK) | value; | |
1882 | } while (cmpxchg(&mm->flags, old, new) != old); | |
1883 | } | |
1884 | ||
1885 | SYSCALL_DEFINE3(execve, | |
1886 | const char __user *, filename, | |
1887 | const char __user *const __user *, argv, | |
1888 | const char __user *const __user *, envp) | |
1889 | { | |
1890 | return do_execve(getname(filename), argv, envp); | |
1891 | } | |
1892 | ||
1893 | SYSCALL_DEFINE5(execveat, | |
1894 | int, fd, const char __user *, filename, | |
1895 | const char __user *const __user *, argv, | |
1896 | const char __user *const __user *, envp, | |
1897 | int, flags) | |
1898 | { | |
1899 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1900 | ||
1901 | return do_execveat(fd, | |
1902 | getname_flags(filename, lookup_flags, NULL), | |
1903 | argv, envp, flags); | |
1904 | } | |
1905 | ||
1906 | #ifdef CONFIG_COMPAT | |
1907 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, | |
1908 | const compat_uptr_t __user *, argv, | |
1909 | const compat_uptr_t __user *, envp) | |
1910 | { | |
1911 | return compat_do_execve(getname(filename), argv, envp); | |
1912 | } | |
1913 | ||
1914 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1915 | const char __user *, filename, | |
1916 | const compat_uptr_t __user *, argv, | |
1917 | const compat_uptr_t __user *, envp, | |
1918 | int, flags) | |
1919 | { | |
1920 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1921 | ||
1922 | return compat_do_execveat(fd, | |
1923 | getname_flags(filename, lookup_flags, NULL), | |
1924 | argv, envp, flags); | |
1925 | } | |
1926 | #endif |