Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/fs/exec.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
9 | * #!-checking implemented by tytso. | |
10 | */ | |
11 | /* | |
12 | * Demand-loading implemented 01.12.91 - no need to read anything but | |
13 | * the header into memory. The inode of the executable is put into | |
14 | * "current->executable", and page faults do the actual loading. Clean. | |
15 | * | |
16 | * Once more I can proudly say that linux stood up to being changed: it | |
17 | * was less than 2 hours work to get demand-loading completely implemented. | |
18 | * | |
19 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, | |
20 | * current->executable is only used by the procfs. This allows a dispatch | |
21 | * table to check for several different types of binary formats. We keep | |
22 | * trying until we recognize the file or we run out of supported binary | |
613cc2b6 | 23 | * formats. |
1da177e4 LT |
24 | */ |
25 | ||
1da177e4 LT |
26 | #include <linux/slab.h> |
27 | #include <linux/file.h> | |
9f3acc31 | 28 | #include <linux/fdtable.h> |
ba92a43d | 29 | #include <linux/mm.h> |
615d6e87 | 30 | #include <linux/vmacache.h> |
1da177e4 LT |
31 | #include <linux/stat.h> |
32 | #include <linux/fcntl.h> | |
ba92a43d | 33 | #include <linux/swap.h> |
74aadce9 | 34 | #include <linux/string.h> |
1da177e4 | 35 | #include <linux/init.h> |
6e84f315 | 36 | #include <linux/sched/mm.h> |
f7ccbae4 | 37 | #include <linux/sched/coredump.h> |
3f07c014 | 38 | #include <linux/sched/signal.h> |
6a3827d7 | 39 | #include <linux/sched/numa_balancing.h> |
29930025 | 40 | #include <linux/sched/task.h> |
ca5b172b | 41 | #include <linux/pagemap.h> |
cdd6c482 | 42 | #include <linux/perf_event.h> |
1da177e4 LT |
43 | #include <linux/highmem.h> |
44 | #include <linux/spinlock.h> | |
45 | #include <linux/key.h> | |
46 | #include <linux/personality.h> | |
47 | #include <linux/binfmts.h> | |
1da177e4 | 48 | #include <linux/utsname.h> |
84d73786 | 49 | #include <linux/pid_namespace.h> |
1da177e4 LT |
50 | #include <linux/module.h> |
51 | #include <linux/namei.h> | |
1da177e4 LT |
52 | #include <linux/mount.h> |
53 | #include <linux/security.h> | |
54 | #include <linux/syscalls.h> | |
8f0ab514 | 55 | #include <linux/tsacct_kern.h> |
9f46080c | 56 | #include <linux/cn_proc.h> |
473ae30b | 57 | #include <linux/audit.h> |
6341c393 | 58 | #include <linux/tracehook.h> |
5f4123be | 59 | #include <linux/kmod.h> |
6110e3ab | 60 | #include <linux/fsnotify.h> |
5ad4e53b | 61 | #include <linux/fs_struct.h> |
3d5992d2 | 62 | #include <linux/oom.h> |
0e028465 | 63 | #include <linux/compat.h> |
b44a7dfc | 64 | #include <linux/vmalloc.h> |
1da177e4 | 65 | |
7c0f6ba6 | 66 | #include <linux/uaccess.h> |
1da177e4 | 67 | #include <asm/mmu_context.h> |
b6a2fea3 | 68 | #include <asm/tlb.h> |
43d2b113 KH |
69 | |
70 | #include <trace/events/task.h> | |
a6f76f23 | 71 | #include "internal.h" |
1da177e4 | 72 | |
4ff16c25 DS |
73 | #include <trace/events/sched.h> |
74 | ||
d6e71144 AC |
75 | int suid_dumpable = 0; |
76 | ||
e4dc1b14 | 77 | static LIST_HEAD(formats); |
1da177e4 LT |
78 | static DEFINE_RWLOCK(binfmt_lock); |
79 | ||
8fc3dc5a | 80 | void __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 81 | { |
8fc3dc5a | 82 | BUG_ON(!fmt); |
92eaa565 ON |
83 | if (WARN_ON(!fmt->load_binary)) |
84 | return; | |
1da177e4 | 85 | write_lock(&binfmt_lock); |
74641f58 IK |
86 | insert ? list_add(&fmt->lh, &formats) : |
87 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 | 88 | write_unlock(&binfmt_lock); |
1da177e4 LT |
89 | } |
90 | ||
74641f58 | 91 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 92 | |
f6b450d4 | 93 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 94 | { |
1da177e4 | 95 | write_lock(&binfmt_lock); |
e4dc1b14 | 96 | list_del(&fmt->lh); |
1da177e4 | 97 | write_unlock(&binfmt_lock); |
1da177e4 LT |
98 | } |
99 | ||
100 | EXPORT_SYMBOL(unregister_binfmt); | |
101 | ||
102 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
103 | { | |
104 | module_put(fmt->module); | |
105 | } | |
106 | ||
90f8572b EB |
107 | bool path_noexec(const struct path *path) |
108 | { | |
109 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
110 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
111 | } | |
112 | ||
69369a70 | 113 | #ifdef CONFIG_USELIB |
1da177e4 LT |
114 | /* |
115 | * Note that a shared library must be both readable and executable due to | |
116 | * security reasons. | |
117 | * | |
118 | * Also note that we take the address to load from from the file itself. | |
119 | */ | |
1e7bfb21 | 120 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 121 | { |
72c2d531 | 122 | struct linux_binfmt *fmt; |
964bd183 | 123 | struct file *file; |
91a27b2a | 124 | struct filename *tmp = getname(library); |
964bd183 | 125 | int error = PTR_ERR(tmp); |
47c805dc AV |
126 | static const struct open_flags uselib_flags = { |
127 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
62fb4a15 | 128 | .acc_mode = MAY_READ | MAY_EXEC, |
f9652e10 AV |
129 | .intent = LOOKUP_OPEN, |
130 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 131 | }; |
964bd183 | 132 | |
6e8341a1 AV |
133 | if (IS_ERR(tmp)) |
134 | goto out; | |
135 | ||
f9652e10 | 136 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); |
6e8341a1 AV |
137 | putname(tmp); |
138 | error = PTR_ERR(file); | |
139 | if (IS_ERR(file)) | |
1da177e4 LT |
140 | goto out; |
141 | ||
142 | error = -EINVAL; | |
496ad9aa | 143 | if (!S_ISREG(file_inode(file)->i_mode)) |
1da177e4 LT |
144 | goto exit; |
145 | ||
30524472 | 146 | error = -EACCES; |
90f8572b | 147 | if (path_noexec(&file->f_path)) |
1da177e4 LT |
148 | goto exit; |
149 | ||
2a12a9d7 | 150 | fsnotify_open(file); |
6110e3ab | 151 | |
1da177e4 | 152 | error = -ENOEXEC; |
1da177e4 | 153 | |
72c2d531 AV |
154 | read_lock(&binfmt_lock); |
155 | list_for_each_entry(fmt, &formats, lh) { | |
156 | if (!fmt->load_shlib) | |
157 | continue; | |
158 | if (!try_module_get(fmt->module)) | |
159 | continue; | |
1da177e4 | 160 | read_unlock(&binfmt_lock); |
72c2d531 AV |
161 | error = fmt->load_shlib(file); |
162 | read_lock(&binfmt_lock); | |
163 | put_binfmt(fmt); | |
164 | if (error != -ENOEXEC) | |
165 | break; | |
1da177e4 | 166 | } |
72c2d531 | 167 | read_unlock(&binfmt_lock); |
6e8341a1 | 168 | exit: |
1da177e4 LT |
169 | fput(file); |
170 | out: | |
171 | return error; | |
1da177e4 | 172 | } |
69369a70 | 173 | #endif /* #ifdef CONFIG_USELIB */ |
1da177e4 | 174 | |
b6a2fea3 | 175 | #ifdef CONFIG_MMU |
ae6b585e ON |
176 | /* |
177 | * The nascent bprm->mm is not visible until exec_mmap() but it can | |
178 | * use a lot of memory, account these pages in current->mm temporary | |
179 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we | |
180 | * change the counter back via acct_arg_size(0). | |
181 | */ | |
0e028465 | 182 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
183 | { |
184 | struct mm_struct *mm = current->mm; | |
185 | long diff = (long)(pages - bprm->vma_pages); | |
186 | ||
187 | if (!mm || !diff) | |
188 | return; | |
189 | ||
190 | bprm->vma_pages = pages; | |
3c77f845 | 191 | add_mm_counter(mm, MM_ANONPAGES, diff); |
3c77f845 ON |
192 | } |
193 | ||
0e028465 | 194 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
195 | int write) |
196 | { | |
197 | struct page *page; | |
198 | int ret; | |
9beae1ea | 199 | unsigned int gup_flags = FOLL_FORCE; |
b6a2fea3 OW |
200 | |
201 | #ifdef CONFIG_STACK_GROWSUP | |
202 | if (write) { | |
d05f3169 | 203 | ret = expand_downwards(bprm->vma, pos); |
b6a2fea3 OW |
204 | if (ret < 0) |
205 | return NULL; | |
206 | } | |
207 | #endif | |
9beae1ea LS |
208 | |
209 | if (write) | |
210 | gup_flags |= FOLL_WRITE; | |
211 | ||
1e987790 DH |
212 | /* |
213 | * We are doing an exec(). 'current' is the process | |
214 | * doing the exec and bprm->mm is the new process's mm. | |
215 | */ | |
9beae1ea | 216 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, |
5b56d49f | 217 | &page, NULL, NULL); |
b6a2fea3 OW |
218 | if (ret <= 0) |
219 | return NULL; | |
220 | ||
655c16a8 ON |
221 | if (write) |
222 | acct_arg_size(bprm, vma_pages(bprm->vma)); | |
b6a2fea3 OW |
223 | |
224 | return page; | |
225 | } | |
226 | ||
227 | static void put_arg_page(struct page *page) | |
228 | { | |
229 | put_page(page); | |
230 | } | |
231 | ||
b6a2fea3 OW |
232 | static void free_arg_pages(struct linux_binprm *bprm) |
233 | { | |
234 | } | |
235 | ||
236 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
237 | struct page *page) | |
238 | { | |
239 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
240 | } | |
241 | ||
242 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
243 | { | |
eaccbfa5 | 244 | int err; |
b6a2fea3 OW |
245 | struct vm_area_struct *vma = NULL; |
246 | struct mm_struct *mm = bprm->mm; | |
247 | ||
490fc053 | 248 | bprm->vma = vma = vm_area_alloc(mm); |
b6a2fea3 | 249 | if (!vma) |
eaccbfa5 | 250 | return -ENOMEM; |
bfd40eaf | 251 | vma_set_anonymous(vma); |
b6a2fea3 | 252 | |
f268dfe9 MH |
253 | if (down_write_killable(&mm->mmap_sem)) { |
254 | err = -EINTR; | |
255 | goto err_free; | |
256 | } | |
b6a2fea3 OW |
257 | |
258 | /* | |
259 | * Place the stack at the largest stack address the architecture | |
260 | * supports. Later, we'll move this to an appropriate place. We don't | |
261 | * use STACK_TOP because that can depend on attributes which aren't | |
262 | * configured yet. | |
263 | */ | |
aacb3d17 | 264 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
265 | vma->vm_end = STACK_TOP_MAX; |
266 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
d9104d1c | 267 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 268 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
462e635e | 269 | |
b6a2fea3 | 270 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 271 | if (err) |
b6a2fea3 | 272 | goto err; |
b6a2fea3 OW |
273 | |
274 | mm->stack_vm = mm->total_vm = 1; | |
fe3d197f | 275 | arch_bprm_mm_init(mm, vma); |
b6a2fea3 | 276 | up_write(&mm->mmap_sem); |
b6a2fea3 | 277 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 278 | return 0; |
b6a2fea3 | 279 | err: |
eaccbfa5 | 280 | up_write(&mm->mmap_sem); |
f268dfe9 | 281 | err_free: |
eaccbfa5 | 282 | bprm->vma = NULL; |
3928d4f5 | 283 | vm_area_free(vma); |
b6a2fea3 OW |
284 | return err; |
285 | } | |
286 | ||
287 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
288 | { | |
289 | return len <= MAX_ARG_STRLEN; | |
290 | } | |
291 | ||
292 | #else | |
293 | ||
0e028465 | 294 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
295 | { |
296 | } | |
297 | ||
0e028465 | 298 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
299 | int write) |
300 | { | |
301 | struct page *page; | |
302 | ||
303 | page = bprm->page[pos / PAGE_SIZE]; | |
304 | if (!page && write) { | |
305 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
306 | if (!page) | |
307 | return NULL; | |
308 | bprm->page[pos / PAGE_SIZE] = page; | |
309 | } | |
310 | ||
311 | return page; | |
312 | } | |
313 | ||
314 | static void put_arg_page(struct page *page) | |
315 | { | |
316 | } | |
317 | ||
318 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
319 | { | |
320 | if (bprm->page[i]) { | |
321 | __free_page(bprm->page[i]); | |
322 | bprm->page[i] = NULL; | |
323 | } | |
324 | } | |
325 | ||
326 | static void free_arg_pages(struct linux_binprm *bprm) | |
327 | { | |
328 | int i; | |
329 | ||
330 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
331 | free_arg_page(bprm, i); | |
332 | } | |
333 | ||
334 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
335 | struct page *page) | |
336 | { | |
337 | } | |
338 | ||
339 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
340 | { | |
341 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
342 | return 0; | |
343 | } | |
344 | ||
345 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
346 | { | |
347 | return len <= bprm->p; | |
348 | } | |
349 | ||
350 | #endif /* CONFIG_MMU */ | |
351 | ||
352 | /* | |
353 | * Create a new mm_struct and populate it with a temporary stack | |
354 | * vm_area_struct. We don't have enough context at this point to set the stack | |
355 | * flags, permissions, and offset, so we use temporary values. We'll update | |
356 | * them later in setup_arg_pages(). | |
357 | */ | |
9cc64cea | 358 | static int bprm_mm_init(struct linux_binprm *bprm) |
b6a2fea3 OW |
359 | { |
360 | int err; | |
361 | struct mm_struct *mm = NULL; | |
362 | ||
363 | bprm->mm = mm = mm_alloc(); | |
364 | err = -ENOMEM; | |
365 | if (!mm) | |
366 | goto err; | |
367 | ||
c31dbb14 KC |
368 | /* Save current stack limit for all calculations made during exec. */ |
369 | task_lock(current->group_leader); | |
370 | bprm->rlim_stack = current->signal->rlim[RLIMIT_STACK]; | |
371 | task_unlock(current->group_leader); | |
372 | ||
b6a2fea3 OW |
373 | err = __bprm_mm_init(bprm); |
374 | if (err) | |
375 | goto err; | |
376 | ||
377 | return 0; | |
378 | ||
379 | err: | |
380 | if (mm) { | |
381 | bprm->mm = NULL; | |
382 | mmdrop(mm); | |
383 | } | |
384 | ||
385 | return err; | |
386 | } | |
387 | ||
ba2d0162 | 388 | struct user_arg_ptr { |
0e028465 ON |
389 | #ifdef CONFIG_COMPAT |
390 | bool is_compat; | |
391 | #endif | |
392 | union { | |
393 | const char __user *const __user *native; | |
394 | #ifdef CONFIG_COMPAT | |
38b983b3 | 395 | const compat_uptr_t __user *compat; |
0e028465 ON |
396 | #endif |
397 | } ptr; | |
ba2d0162 ON |
398 | }; |
399 | ||
400 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
1d1dbf81 | 401 | { |
0e028465 ON |
402 | const char __user *native; |
403 | ||
404 | #ifdef CONFIG_COMPAT | |
405 | if (unlikely(argv.is_compat)) { | |
406 | compat_uptr_t compat; | |
407 | ||
408 | if (get_user(compat, argv.ptr.compat + nr)) | |
409 | return ERR_PTR(-EFAULT); | |
1d1dbf81 | 410 | |
0e028465 ON |
411 | return compat_ptr(compat); |
412 | } | |
413 | #endif | |
414 | ||
415 | if (get_user(native, argv.ptr.native + nr)) | |
1d1dbf81 ON |
416 | return ERR_PTR(-EFAULT); |
417 | ||
0e028465 | 418 | return native; |
1d1dbf81 ON |
419 | } |
420 | ||
1da177e4 LT |
421 | /* |
422 | * count() counts the number of strings in array ARGV. | |
423 | */ | |
ba2d0162 | 424 | static int count(struct user_arg_ptr argv, int max) |
1da177e4 LT |
425 | { |
426 | int i = 0; | |
427 | ||
0e028465 | 428 | if (argv.ptr.native != NULL) { |
1da177e4 | 429 | for (;;) { |
1d1dbf81 | 430 | const char __user *p = get_user_arg_ptr(argv, i); |
1da177e4 | 431 | |
1da177e4 LT |
432 | if (!p) |
433 | break; | |
1d1dbf81 ON |
434 | |
435 | if (IS_ERR(p)) | |
436 | return -EFAULT; | |
437 | ||
6d92d4f6 | 438 | if (i >= max) |
1da177e4 | 439 | return -E2BIG; |
6d92d4f6 | 440 | ++i; |
9aea5a65 RM |
441 | |
442 | if (fatal_signal_pending(current)) | |
443 | return -ERESTARTNOHAND; | |
1da177e4 LT |
444 | cond_resched(); |
445 | } | |
446 | } | |
447 | return i; | |
448 | } | |
449 | ||
655c16a8 ON |
450 | static int prepare_arg_pages(struct linux_binprm *bprm, |
451 | struct user_arg_ptr argv, struct user_arg_ptr envp) | |
452 | { | |
453 | unsigned long limit, ptr_size; | |
454 | ||
455 | bprm->argc = count(argv, MAX_ARG_STRINGS); | |
456 | if (bprm->argc < 0) | |
457 | return bprm->argc; | |
458 | ||
459 | bprm->envc = count(envp, MAX_ARG_STRINGS); | |
460 | if (bprm->envc < 0) | |
461 | return bprm->envc; | |
462 | ||
463 | /* | |
464 | * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM | |
465 | * (whichever is smaller) for the argv+env strings. | |
466 | * This ensures that: | |
467 | * - the remaining binfmt code will not run out of stack space, | |
468 | * - the program will have a reasonable amount of stack left | |
469 | * to work from. | |
470 | */ | |
471 | limit = _STK_LIM / 4 * 3; | |
472 | limit = min(limit, bprm->rlim_stack.rlim_cur / 4); | |
473 | /* | |
474 | * We've historically supported up to 32 pages (ARG_MAX) | |
475 | * of argument strings even with small stacks | |
476 | */ | |
477 | limit = max_t(unsigned long, limit, ARG_MAX); | |
478 | /* | |
479 | * We must account for the size of all the argv and envp pointers to | |
480 | * the argv and envp strings, since they will also take up space in | |
481 | * the stack. They aren't stored until much later when we can't | |
482 | * signal to the parent that the child has run out of stack space. | |
483 | * Instead, calculate it here so it's possible to fail gracefully. | |
484 | */ | |
485 | ptr_size = (bprm->argc + bprm->envc) * sizeof(void *); | |
486 | if (limit <= ptr_size) | |
487 | return -E2BIG; | |
488 | limit -= ptr_size; | |
489 | ||
490 | bprm->argmin = bprm->p - limit; | |
491 | return 0; | |
492 | } | |
493 | ||
1da177e4 | 494 | /* |
b6a2fea3 OW |
495 | * 'copy_strings()' copies argument/environment strings from the old |
496 | * processes's memory to the new process's stack. The call to get_user_pages() | |
497 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 498 | */ |
ba2d0162 | 499 | static int copy_strings(int argc, struct user_arg_ptr argv, |
75c96f85 | 500 | struct linux_binprm *bprm) |
1da177e4 LT |
501 | { |
502 | struct page *kmapped_page = NULL; | |
503 | char *kaddr = NULL; | |
b6a2fea3 | 504 | unsigned long kpos = 0; |
1da177e4 LT |
505 | int ret; |
506 | ||
507 | while (argc-- > 0) { | |
d7627467 | 508 | const char __user *str; |
1da177e4 LT |
509 | int len; |
510 | unsigned long pos; | |
511 | ||
1d1dbf81 ON |
512 | ret = -EFAULT; |
513 | str = get_user_arg_ptr(argv, argc); | |
514 | if (IS_ERR(str)) | |
1da177e4 | 515 | goto out; |
1da177e4 | 516 | |
1d1dbf81 ON |
517 | len = strnlen_user(str, MAX_ARG_STRLEN); |
518 | if (!len) | |
519 | goto out; | |
520 | ||
521 | ret = -E2BIG; | |
522 | if (!valid_arg_len(bprm, len)) | |
1da177e4 | 523 | goto out; |
1da177e4 | 524 | |
b6a2fea3 | 525 | /* We're going to work our way backwords. */ |
1da177e4 | 526 | pos = bprm->p; |
b6a2fea3 OW |
527 | str += len; |
528 | bprm->p -= len; | |
655c16a8 ON |
529 | #ifdef CONFIG_MMU |
530 | if (bprm->p < bprm->argmin) | |
531 | goto out; | |
532 | #endif | |
1da177e4 LT |
533 | |
534 | while (len > 0) { | |
1da177e4 | 535 | int offset, bytes_to_copy; |
1da177e4 | 536 | |
9aea5a65 RM |
537 | if (fatal_signal_pending(current)) { |
538 | ret = -ERESTARTNOHAND; | |
539 | goto out; | |
540 | } | |
7993bc1f RM |
541 | cond_resched(); |
542 | ||
1da177e4 | 543 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
544 | if (offset == 0) |
545 | offset = PAGE_SIZE; | |
546 | ||
547 | bytes_to_copy = offset; | |
548 | if (bytes_to_copy > len) | |
549 | bytes_to_copy = len; | |
550 | ||
551 | offset -= bytes_to_copy; | |
552 | pos -= bytes_to_copy; | |
553 | str -= bytes_to_copy; | |
554 | len -= bytes_to_copy; | |
555 | ||
556 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
557 | struct page *page; | |
558 | ||
559 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 560 | if (!page) { |
b6a2fea3 | 561 | ret = -E2BIG; |
1da177e4 LT |
562 | goto out; |
563 | } | |
1da177e4 | 564 | |
b6a2fea3 OW |
565 | if (kmapped_page) { |
566 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 567 | kunmap(kmapped_page); |
b6a2fea3 OW |
568 | put_arg_page(kmapped_page); |
569 | } | |
1da177e4 LT |
570 | kmapped_page = page; |
571 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
572 | kpos = pos & PAGE_MASK; |
573 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 574 | } |
b6a2fea3 | 575 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
576 | ret = -EFAULT; |
577 | goto out; | |
578 | } | |
1da177e4 LT |
579 | } |
580 | } | |
581 | ret = 0; | |
582 | out: | |
b6a2fea3 OW |
583 | if (kmapped_page) { |
584 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 585 | kunmap(kmapped_page); |
b6a2fea3 OW |
586 | put_arg_page(kmapped_page); |
587 | } | |
1da177e4 LT |
588 | return ret; |
589 | } | |
590 | ||
591 | /* | |
592 | * Like copy_strings, but get argv and its values from kernel memory. | |
593 | */ | |
ba2d0162 | 594 | int copy_strings_kernel(int argc, const char *const *__argv, |
d7627467 | 595 | struct linux_binprm *bprm) |
1da177e4 LT |
596 | { |
597 | int r; | |
598 | mm_segment_t oldfs = get_fs(); | |
ba2d0162 | 599 | struct user_arg_ptr argv = { |
0e028465 | 600 | .ptr.native = (const char __user *const __user *)__argv, |
ba2d0162 ON |
601 | }; |
602 | ||
1da177e4 | 603 | set_fs(KERNEL_DS); |
ba2d0162 | 604 | r = copy_strings(argc, argv, bprm); |
1da177e4 | 605 | set_fs(oldfs); |
ba2d0162 | 606 | |
1da177e4 LT |
607 | return r; |
608 | } | |
1da177e4 LT |
609 | EXPORT_SYMBOL(copy_strings_kernel); |
610 | ||
611 | #ifdef CONFIG_MMU | |
b6a2fea3 | 612 | |
1da177e4 | 613 | /* |
b6a2fea3 OW |
614 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
615 | * the binfmt code determines where the new stack should reside, we shift it to | |
616 | * its final location. The process proceeds as follows: | |
1da177e4 | 617 | * |
b6a2fea3 OW |
618 | * 1) Use shift to calculate the new vma endpoints. |
619 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
620 | * arguments passed to subsequent functions are consistent. | |
621 | * 3) Move vma's page tables to the new range. | |
622 | * 4) Free up any cleared pgd range. | |
623 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 624 | */ |
b6a2fea3 | 625 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
626 | { |
627 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
628 | unsigned long old_start = vma->vm_start; |
629 | unsigned long old_end = vma->vm_end; | |
630 | unsigned long length = old_end - old_start; | |
631 | unsigned long new_start = old_start - shift; | |
632 | unsigned long new_end = old_end - shift; | |
d16dfc55 | 633 | struct mmu_gather tlb; |
1da177e4 | 634 | |
b6a2fea3 | 635 | BUG_ON(new_start > new_end); |
1da177e4 | 636 | |
b6a2fea3 OW |
637 | /* |
638 | * ensure there are no vmas between where we want to go | |
639 | * and where we are | |
640 | */ | |
641 | if (vma != find_vma(mm, new_start)) | |
642 | return -EFAULT; | |
643 | ||
644 | /* | |
645 | * cover the whole range: [new_start, old_end) | |
646 | */ | |
5beb4930 RR |
647 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
648 | return -ENOMEM; | |
b6a2fea3 OW |
649 | |
650 | /* | |
651 | * move the page tables downwards, on failure we rely on | |
652 | * process cleanup to remove whatever mess we made. | |
653 | */ | |
654 | if (length != move_page_tables(vma, old_start, | |
38a76013 | 655 | vma, new_start, length, false)) |
b6a2fea3 OW |
656 | return -ENOMEM; |
657 | ||
658 | lru_add_drain(); | |
2b047252 | 659 | tlb_gather_mmu(&tlb, mm, old_start, old_end); |
b6a2fea3 OW |
660 | if (new_end > old_start) { |
661 | /* | |
662 | * when the old and new regions overlap clear from new_end. | |
663 | */ | |
d16dfc55 | 664 | free_pgd_range(&tlb, new_end, old_end, new_end, |
6ee8630e | 665 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
b6a2fea3 OW |
666 | } else { |
667 | /* | |
668 | * otherwise, clean from old_start; this is done to not touch | |
669 | * the address space in [new_end, old_start) some architectures | |
670 | * have constraints on va-space that make this illegal (IA64) - | |
671 | * for the others its just a little faster. | |
672 | */ | |
d16dfc55 | 673 | free_pgd_range(&tlb, old_start, old_end, new_end, |
6ee8630e | 674 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
1da177e4 | 675 | } |
2b047252 | 676 | tlb_finish_mmu(&tlb, old_start, old_end); |
b6a2fea3 OW |
677 | |
678 | /* | |
5beb4930 | 679 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
680 | */ |
681 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
682 | ||
683 | return 0; | |
1da177e4 LT |
684 | } |
685 | ||
b6a2fea3 OW |
686 | /* |
687 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
688 | * the stack is optionally relocated, and some extra space is added. | |
689 | */ | |
1da177e4 LT |
690 | int setup_arg_pages(struct linux_binprm *bprm, |
691 | unsigned long stack_top, | |
692 | int executable_stack) | |
693 | { | |
b6a2fea3 OW |
694 | unsigned long ret; |
695 | unsigned long stack_shift; | |
1da177e4 | 696 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
697 | struct vm_area_struct *vma = bprm->vma; |
698 | struct vm_area_struct *prev = NULL; | |
699 | unsigned long vm_flags; | |
700 | unsigned long stack_base; | |
803bf5ec MN |
701 | unsigned long stack_size; |
702 | unsigned long stack_expand; | |
703 | unsigned long rlim_stack; | |
1da177e4 LT |
704 | |
705 | #ifdef CONFIG_STACK_GROWSUP | |
d71f290b | 706 | /* Limit stack size */ |
c31dbb14 | 707 | stack_base = bprm->rlim_stack.rlim_max; |
d71f290b JH |
708 | if (stack_base > STACK_SIZE_MAX) |
709 | stack_base = STACK_SIZE_MAX; | |
1da177e4 | 710 | |
d045c77c HD |
711 | /* Add space for stack randomization. */ |
712 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
713 | ||
b6a2fea3 OW |
714 | /* Make sure we didn't let the argument array grow too large. */ |
715 | if (vma->vm_end - vma->vm_start > stack_base) | |
716 | return -ENOMEM; | |
1da177e4 | 717 | |
b6a2fea3 | 718 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 719 | |
b6a2fea3 OW |
720 | stack_shift = vma->vm_start - stack_base; |
721 | mm->arg_start = bprm->p - stack_shift; | |
722 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 723 | #else |
b6a2fea3 OW |
724 | stack_top = arch_align_stack(stack_top); |
725 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
726 | |
727 | if (unlikely(stack_top < mmap_min_addr) || | |
728 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
729 | return -ENOMEM; | |
730 | ||
b6a2fea3 OW |
731 | stack_shift = vma->vm_end - stack_top; |
732 | ||
733 | bprm->p -= stack_shift; | |
1da177e4 | 734 | mm->arg_start = bprm->p; |
1da177e4 LT |
735 | #endif |
736 | ||
1da177e4 | 737 | if (bprm->loader) |
b6a2fea3 OW |
738 | bprm->loader -= stack_shift; |
739 | bprm->exec -= stack_shift; | |
1da177e4 | 740 | |
f268dfe9 MH |
741 | if (down_write_killable(&mm->mmap_sem)) |
742 | return -EINTR; | |
743 | ||
96a8e13e | 744 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
745 | |
746 | /* | |
747 | * Adjust stack execute permissions; explicitly enable for | |
748 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
749 | * (arch default) otherwise. | |
750 | */ | |
751 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
752 | vm_flags |= VM_EXEC; | |
753 | else if (executable_stack == EXSTACK_DISABLE_X) | |
754 | vm_flags &= ~VM_EXEC; | |
755 | vm_flags |= mm->def_flags; | |
a8bef8ff | 756 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
757 | |
758 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
759 | vm_flags); | |
760 | if (ret) | |
761 | goto out_unlock; | |
762 | BUG_ON(prev != vma); | |
763 | ||
764 | /* Move stack pages down in memory. */ | |
765 | if (stack_shift) { | |
766 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
767 | if (ret) |
768 | goto out_unlock; | |
1da177e4 LT |
769 | } |
770 | ||
a8bef8ff MG |
771 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
772 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
773 | ||
5ef097dd | 774 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
775 | stack_size = vma->vm_end - vma->vm_start; |
776 | /* | |
777 | * Align this down to a page boundary as expand_stack | |
778 | * will align it up. | |
779 | */ | |
c31dbb14 | 780 | rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK; |
b6a2fea3 | 781 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
782 | if (stack_size + stack_expand > rlim_stack) |
783 | stack_base = vma->vm_start + rlim_stack; | |
784 | else | |
785 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 786 | #else |
803bf5ec MN |
787 | if (stack_size + stack_expand > rlim_stack) |
788 | stack_base = vma->vm_end - rlim_stack; | |
789 | else | |
790 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 791 | #endif |
3af9e859 | 792 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
793 | ret = expand_stack(vma, stack_base); |
794 | if (ret) | |
795 | ret = -EFAULT; | |
796 | ||
797 | out_unlock: | |
1da177e4 | 798 | up_write(&mm->mmap_sem); |
fc63cf23 | 799 | return ret; |
1da177e4 | 800 | } |
1da177e4 LT |
801 | EXPORT_SYMBOL(setup_arg_pages); |
802 | ||
7e7ec6a9 NP |
803 | #else |
804 | ||
805 | /* | |
806 | * Transfer the program arguments and environment from the holding pages | |
807 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
808 | */ | |
809 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
810 | unsigned long *sp_location) | |
811 | { | |
812 | unsigned long index, stop, sp; | |
813 | int ret = 0; | |
814 | ||
815 | stop = bprm->p >> PAGE_SHIFT; | |
816 | sp = *sp_location; | |
817 | ||
818 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
819 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
820 | char *src = kmap(bprm->page[index]) + offset; | |
821 | sp -= PAGE_SIZE - offset; | |
822 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
823 | ret = -EFAULT; | |
824 | kunmap(bprm->page[index]); | |
825 | if (ret) | |
826 | goto out; | |
827 | } | |
828 | ||
829 | *sp_location = sp; | |
830 | ||
831 | out: | |
832 | return ret; | |
833 | } | |
834 | EXPORT_SYMBOL(transfer_args_to_stack); | |
835 | ||
1da177e4 LT |
836 | #endif /* CONFIG_MMU */ |
837 | ||
51f39a1f | 838 | static struct file *do_open_execat(int fd, struct filename *name, int flags) |
1da177e4 | 839 | { |
1da177e4 | 840 | struct file *file; |
e56b6a5d | 841 | int err; |
51f39a1f | 842 | struct open_flags open_exec_flags = { |
47c805dc | 843 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
62fb4a15 | 844 | .acc_mode = MAY_EXEC, |
f9652e10 AV |
845 | .intent = LOOKUP_OPEN, |
846 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 847 | }; |
1da177e4 | 848 | |
51f39a1f DD |
849 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
850 | return ERR_PTR(-EINVAL); | |
851 | if (flags & AT_SYMLINK_NOFOLLOW) | |
852 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
853 | if (flags & AT_EMPTY_PATH) | |
854 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
855 | ||
856 | file = do_filp_open(fd, name, &open_exec_flags); | |
6e8341a1 | 857 | if (IS_ERR(file)) |
e56b6a5d CH |
858 | goto out; |
859 | ||
860 | err = -EACCES; | |
496ad9aa | 861 | if (!S_ISREG(file_inode(file)->i_mode)) |
6e8341a1 | 862 | goto exit; |
e56b6a5d | 863 | |
90f8572b | 864 | if (path_noexec(&file->f_path)) |
6e8341a1 | 865 | goto exit; |
e56b6a5d CH |
866 | |
867 | err = deny_write_access(file); | |
6e8341a1 AV |
868 | if (err) |
869 | goto exit; | |
1da177e4 | 870 | |
51f39a1f DD |
871 | if (name->name[0] != '\0') |
872 | fsnotify_open(file); | |
873 | ||
6e8341a1 | 874 | out: |
e56b6a5d CH |
875 | return file; |
876 | ||
6e8341a1 AV |
877 | exit: |
878 | fput(file); | |
e56b6a5d CH |
879 | return ERR_PTR(err); |
880 | } | |
c4ad8f98 LT |
881 | |
882 | struct file *open_exec(const char *name) | |
883 | { | |
51689104 PM |
884 | struct filename *filename = getname_kernel(name); |
885 | struct file *f = ERR_CAST(filename); | |
886 | ||
887 | if (!IS_ERR(filename)) { | |
888 | f = do_open_execat(AT_FDCWD, filename, 0); | |
889 | putname(filename); | |
890 | } | |
891 | return f; | |
c4ad8f98 | 892 | } |
1da177e4 LT |
893 | EXPORT_SYMBOL(open_exec); |
894 | ||
b44a7dfc | 895 | int kernel_read_file(struct file *file, void **buf, loff_t *size, |
bc8ca5b9 | 896 | loff_t max_size, enum kernel_read_file_id id) |
b44a7dfc MZ |
897 | { |
898 | loff_t i_size, pos; | |
899 | ssize_t bytes = 0; | |
900 | int ret; | |
901 | ||
902 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
903 | return -EINVAL; | |
904 | ||
7bd698b3 | 905 | ret = deny_write_access(file); |
39eeb4fb MZ |
906 | if (ret) |
907 | return ret; | |
908 | ||
7bd698b3 | 909 | ret = security_kernel_read_file(file, id); |
39d637af | 910 | if (ret) |
7bd698b3 | 911 | goto out; |
39d637af | 912 | |
b44a7dfc | 913 | i_size = i_size_read(file_inode(file)); |
39d637af DK |
914 | if (i_size <= 0) { |
915 | ret = -EINVAL; | |
916 | goto out; | |
917 | } | |
691115c3 EB |
918 | if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) { |
919 | ret = -EFBIG; | |
920 | goto out; | |
921 | } | |
b44a7dfc | 922 | |
a098ecd2 SB |
923 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) |
924 | *buf = vmalloc(i_size); | |
39d637af DK |
925 | if (!*buf) { |
926 | ret = -ENOMEM; | |
927 | goto out; | |
928 | } | |
b44a7dfc MZ |
929 | |
930 | pos = 0; | |
931 | while (pos < i_size) { | |
bdd1d2d3 | 932 | bytes = kernel_read(file, *buf + pos, i_size - pos, &pos); |
b44a7dfc MZ |
933 | if (bytes < 0) { |
934 | ret = bytes; | |
f612acfa | 935 | goto out_free; |
b44a7dfc MZ |
936 | } |
937 | ||
938 | if (bytes == 0) | |
939 | break; | |
b44a7dfc MZ |
940 | } |
941 | ||
942 | if (pos != i_size) { | |
943 | ret = -EIO; | |
39d637af | 944 | goto out_free; |
b44a7dfc MZ |
945 | } |
946 | ||
bc8ca5b9 | 947 | ret = security_kernel_post_read_file(file, *buf, i_size, id); |
b44a7dfc MZ |
948 | if (!ret) |
949 | *size = pos; | |
950 | ||
39d637af | 951 | out_free: |
b44a7dfc | 952 | if (ret < 0) { |
a098ecd2 SB |
953 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { |
954 | vfree(*buf); | |
955 | *buf = NULL; | |
956 | } | |
b44a7dfc | 957 | } |
39d637af DK |
958 | |
959 | out: | |
960 | allow_write_access(file); | |
b44a7dfc MZ |
961 | return ret; |
962 | } | |
963 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
964 | ||
711aab1d | 965 | int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, |
09596b94 MZ |
966 | loff_t max_size, enum kernel_read_file_id id) |
967 | { | |
968 | struct file *file; | |
969 | int ret; | |
970 | ||
971 | if (!path || !*path) | |
972 | return -EINVAL; | |
973 | ||
974 | file = filp_open(path, O_RDONLY, 0); | |
975 | if (IS_ERR(file)) | |
976 | return PTR_ERR(file); | |
977 | ||
978 | ret = kernel_read_file(file, buf, size, max_size, id); | |
979 | fput(file); | |
980 | return ret; | |
981 | } | |
982 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
983 | ||
b844f0ec MZ |
984 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, |
985 | enum kernel_read_file_id id) | |
986 | { | |
987 | struct fd f = fdget(fd); | |
988 | int ret = -EBADF; | |
989 | ||
990 | if (!f.file) | |
991 | goto out; | |
992 | ||
993 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
994 | out: | |
995 | fdput(f); | |
996 | return ret; | |
997 | } | |
998 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
999 | ||
3dc20cb2 AV |
1000 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) |
1001 | { | |
ec695579 | 1002 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); |
3dc20cb2 AV |
1003 | if (res > 0) |
1004 | flush_icache_range(addr, addr + len); | |
1005 | return res; | |
1006 | } | |
1007 | EXPORT_SYMBOL(read_code); | |
1008 | ||
1da177e4 LT |
1009 | static int exec_mmap(struct mm_struct *mm) |
1010 | { | |
1011 | struct task_struct *tsk; | |
615d6e87 | 1012 | struct mm_struct *old_mm, *active_mm; |
1da177e4 LT |
1013 | |
1014 | /* Notify parent that we're no longer interested in the old VM */ | |
1015 | tsk = current; | |
1016 | old_mm = current->mm; | |
4610ba7a | 1017 | exec_mm_release(tsk, old_mm); |
1da177e4 LT |
1018 | |
1019 | if (old_mm) { | |
4fe7efdb | 1020 | sync_mm_rss(old_mm); |
1da177e4 LT |
1021 | /* |
1022 | * Make sure that if there is a core dump in progress | |
1023 | * for the old mm, we get out and die instead of going | |
1024 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 1025 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
1026 | */ |
1027 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 1028 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
1029 | up_read(&old_mm->mmap_sem); |
1030 | return -EINTR; | |
1031 | } | |
1032 | } | |
1033 | task_lock(tsk); | |
1034 | active_mm = tsk->active_mm; | |
227a4aad | 1035 | membarrier_exec_mmap(mm); |
1da177e4 LT |
1036 | tsk->mm = mm; |
1037 | tsk->active_mm = mm; | |
1038 | activate_mm(active_mm, mm); | |
615d6e87 DB |
1039 | tsk->mm->vmacache_seqnum = 0; |
1040 | vmacache_flush(tsk); | |
1da177e4 | 1041 | task_unlock(tsk); |
1da177e4 LT |
1042 | if (old_mm) { |
1043 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 1044 | BUG_ON(active_mm != old_mm); |
701085b2 | 1045 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
31a78f23 | 1046 | mm_update_next_owner(old_mm); |
1da177e4 LT |
1047 | mmput(old_mm); |
1048 | return 0; | |
1049 | } | |
1050 | mmdrop(active_mm); | |
1051 | return 0; | |
1052 | } | |
1053 | ||
1054 | /* | |
1055 | * This function makes sure the current process has its own signal table, | |
1056 | * so that flush_signal_handlers can later reset the handlers without | |
1057 | * disturbing other processes. (Other processes might share the signal | |
1058 | * table via the CLONE_SIGHAND option to clone().) | |
1059 | */ | |
858119e1 | 1060 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
1061 | { |
1062 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 1063 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 1064 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 1065 | |
aafe6c2a | 1066 | if (thread_group_empty(tsk)) |
1da177e4 LT |
1067 | goto no_thread_group; |
1068 | ||
1069 | /* | |
1070 | * Kill all other threads in the thread group. | |
1da177e4 | 1071 | */ |
1da177e4 | 1072 | spin_lock_irq(lock); |
ed5d2cac | 1073 | if (signal_group_exit(sig)) { |
1da177e4 LT |
1074 | /* |
1075 | * Another group action in progress, just | |
1076 | * return so that the signal is processed. | |
1077 | */ | |
1078 | spin_unlock_irq(lock); | |
1da177e4 LT |
1079 | return -EAGAIN; |
1080 | } | |
d344193a | 1081 | |
ed5d2cac | 1082 | sig->group_exit_task = tsk; |
d344193a ON |
1083 | sig->notify_count = zap_other_threads(tsk); |
1084 | if (!thread_group_leader(tsk)) | |
1085 | sig->notify_count--; | |
1da177e4 | 1086 | |
d344193a | 1087 | while (sig->notify_count) { |
d5bbd43d | 1088 | __set_current_state(TASK_KILLABLE); |
1da177e4 | 1089 | spin_unlock_irq(lock); |
a72173ec | 1090 | schedule(); |
08d405c8 | 1091 | if (__fatal_signal_pending(tsk)) |
d5bbd43d | 1092 | goto killed; |
1da177e4 LT |
1093 | spin_lock_irq(lock); |
1094 | } | |
1da177e4 LT |
1095 | spin_unlock_irq(lock); |
1096 | ||
1097 | /* | |
1098 | * At this point all other threads have exited, all we have to | |
1099 | * do is to wait for the thread group leader to become inactive, | |
1100 | * and to assume its PID: | |
1101 | */ | |
aafe6c2a | 1102 | if (!thread_group_leader(tsk)) { |
8187926b | 1103 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 1104 | |
6db840fa | 1105 | for (;;) { |
780de9dd | 1106 | cgroup_threadgroup_change_begin(tsk); |
6db840fa | 1107 | write_lock_irq(&tasklist_lock); |
dfcce791 KT |
1108 | /* |
1109 | * Do this under tasklist_lock to ensure that | |
1110 | * exit_notify() can't miss ->group_exit_task | |
1111 | */ | |
1112 | sig->notify_count = -1; | |
6db840fa ON |
1113 | if (likely(leader->exit_state)) |
1114 | break; | |
d5bbd43d | 1115 | __set_current_state(TASK_KILLABLE); |
6db840fa | 1116 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1117 | cgroup_threadgroup_change_end(tsk); |
a72173ec | 1118 | schedule(); |
08d405c8 | 1119 | if (__fatal_signal_pending(tsk)) |
d5bbd43d | 1120 | goto killed; |
6db840fa | 1121 | } |
1da177e4 | 1122 | |
f5e90281 RM |
1123 | /* |
1124 | * The only record we have of the real-time age of a | |
1125 | * process, regardless of execs it's done, is start_time. | |
1126 | * All the past CPU time is accumulated in signal_struct | |
1127 | * from sister threads now dead. But in this non-leader | |
1128 | * exec, nothing survives from the original leader thread, | |
1129 | * whose birth marks the true age of this process now. | |
1130 | * When we take on its identity by switching to its PID, we | |
1131 | * also take its birthdate (always earlier than our own). | |
1132 | */ | |
aafe6c2a | 1133 | tsk->start_time = leader->start_time; |
cf25e24d | 1134 | tsk->start_boottime = leader->start_boottime; |
f5e90281 | 1135 | |
bac0abd6 PE |
1136 | BUG_ON(!same_thread_group(leader, tsk)); |
1137 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
1138 | /* |
1139 | * An exec() starts a new thread group with the | |
1140 | * TGID of the previous thread group. Rehash the | |
1141 | * two threads with a switched PID, and release | |
1142 | * the former thread group leader: | |
1143 | */ | |
d73d6529 EB |
1144 | |
1145 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
1146 | * The old leader becomes a thread of the this thread group. |
1147 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
1148 | * is called. Odd but simple and correct. |
1149 | */ | |
aafe6c2a | 1150 | tsk->pid = leader->pid; |
3f418548 | 1151 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
6883f81a | 1152 | transfer_pid(leader, tsk, PIDTYPE_TGID); |
aafe6c2a EB |
1153 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
1154 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 1155 | |
aafe6c2a | 1156 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 1157 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 1158 | |
aafe6c2a EB |
1159 | tsk->group_leader = tsk; |
1160 | leader->group_leader = tsk; | |
de12a787 | 1161 | |
aafe6c2a | 1162 | tsk->exit_signal = SIGCHLD; |
087806b1 | 1163 | leader->exit_signal = -1; |
962b564c ON |
1164 | |
1165 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1166 | leader->exit_state = EXIT_DEAD; | |
eac1b5e5 ON |
1167 | |
1168 | /* | |
1169 | * We are going to release_task()->ptrace_unlink() silently, | |
1170 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1171 | * the tracer wont't block again waiting for this thread. | |
1172 | */ | |
1173 | if (unlikely(leader->ptrace)) | |
1174 | __wake_up_parent(leader, leader->parent); | |
1da177e4 | 1175 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1176 | cgroup_threadgroup_change_end(tsk); |
8187926b ON |
1177 | |
1178 | release_task(leader); | |
ed5d2cac | 1179 | } |
1da177e4 | 1180 | |
6db840fa ON |
1181 | sig->group_exit_task = NULL; |
1182 | sig->notify_count = 0; | |
1da177e4 LT |
1183 | |
1184 | no_thread_group: | |
e6368253 ON |
1185 | /* we have changed execution domain */ |
1186 | tsk->exit_signal = SIGCHLD; | |
1187 | ||
baa73d9e | 1188 | #ifdef CONFIG_POSIX_TIMERS |
1da177e4 | 1189 | exit_itimers(sig); |
cbaffba1 | 1190 | flush_itimer_signals(); |
baa73d9e | 1191 | #endif |
329f7dba | 1192 | |
d036bda7 | 1193 | if (refcount_read(&oldsighand->count) != 1) { |
b2c903b8 | 1194 | struct sighand_struct *newsighand; |
1da177e4 | 1195 | /* |
b2c903b8 ON |
1196 | * This ->sighand is shared with the CLONE_SIGHAND |
1197 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 1198 | */ |
b2c903b8 ON |
1199 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
1200 | if (!newsighand) | |
1201 | return -ENOMEM; | |
1202 | ||
d036bda7 | 1203 | refcount_set(&newsighand->count, 1); |
1da177e4 LT |
1204 | memcpy(newsighand->action, oldsighand->action, |
1205 | sizeof(newsighand->action)); | |
1206 | ||
1207 | write_lock_irq(&tasklist_lock); | |
1208 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 1209 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
1210 | spin_unlock(&oldsighand->siglock); |
1211 | write_unlock_irq(&tasklist_lock); | |
1212 | ||
fba2afaa | 1213 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
1214 | } |
1215 | ||
aafe6c2a | 1216 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 | 1217 | return 0; |
d5bbd43d ON |
1218 | |
1219 | killed: | |
1220 | /* protects against exit_notify() and __exit_signal() */ | |
1221 | read_lock(&tasklist_lock); | |
1222 | sig->group_exit_task = NULL; | |
1223 | sig->notify_count = 0; | |
1224 | read_unlock(&tasklist_lock); | |
1225 | return -EAGAIN; | |
1da177e4 | 1226 | } |
0840a90d | 1227 | |
3756f640 | 1228 | char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk) |
1da177e4 | 1229 | { |
1da177e4 | 1230 | task_lock(tsk); |
3756f640 | 1231 | strncpy(buf, tsk->comm, buf_size); |
1da177e4 | 1232 | task_unlock(tsk); |
59714d65 | 1233 | return buf; |
1da177e4 | 1234 | } |
3756f640 | 1235 | EXPORT_SYMBOL_GPL(__get_task_comm); |
1da177e4 | 1236 | |
6a6d27de AV |
1237 | /* |
1238 | * These functions flushes out all traces of the currently running executable | |
1239 | * so that a new one can be started | |
1240 | */ | |
1241 | ||
82b89778 | 1242 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) |
1da177e4 LT |
1243 | { |
1244 | task_lock(tsk); | |
43d2b113 | 1245 | trace_task_rename(tsk, buf); |
1da177e4 LT |
1246 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1247 | task_unlock(tsk); | |
82b89778 | 1248 | perf_event_comm(tsk, exec); |
1da177e4 LT |
1249 | } |
1250 | ||
a9208e42 KC |
1251 | /* |
1252 | * Calling this is the point of no return. None of the failures will be | |
1253 | * seen by userspace since either the process is already taking a fatal | |
1254 | * signal (via de_thread() or coredump), or will have SEGV raised | |
1255 | * (after exec_mmap()) by search_binary_handlers (see below). | |
1256 | */ | |
1da177e4 LT |
1257 | int flush_old_exec(struct linux_binprm * bprm) |
1258 | { | |
221af7f8 | 1259 | int retval; |
1da177e4 LT |
1260 | |
1261 | /* | |
1262 | * Make sure we have a private signal table and that | |
1263 | * we are unassociated from the previous thread group. | |
1264 | */ | |
1265 | retval = de_thread(current); | |
1266 | if (retval) | |
1267 | goto out; | |
1268 | ||
6e399cd1 DB |
1269 | /* |
1270 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1271 | * not visibile until then. This also enables the update | |
1272 | * to be lockless. | |
1273 | */ | |
925d1c40 | 1274 | set_mm_exe_file(bprm->mm, bprm->file); |
6e399cd1 | 1275 | |
1da177e4 LT |
1276 | /* |
1277 | * Release all of the old mmap stuff | |
1278 | */ | |
3c77f845 | 1279 | acct_arg_size(bprm, 0); |
1da177e4 LT |
1280 | retval = exec_mmap(bprm->mm); |
1281 | if (retval) | |
fd8328be | 1282 | goto out; |
1da177e4 | 1283 | |
a9208e42 KC |
1284 | /* |
1285 | * After clearing bprm->mm (to mark that current is using the | |
1286 | * prepared mm now), we have nothing left of the original | |
1287 | * process. If anything from here on returns an error, the check | |
1288 | * in search_binary_handler() will SEGV current. | |
1289 | */ | |
1290 | bprm->mm = NULL; | |
7ab02af4 | 1291 | |
dac853ae | 1292 | set_fs(USER_DS); |
b88fae64 ZY |
1293 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | |
1294 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
7ab02af4 LT |
1295 | flush_thread(); |
1296 | current->personality &= ~bprm->per_clear; | |
1297 | ||
613cc2b6 AS |
1298 | /* |
1299 | * We have to apply CLOEXEC before we change whether the process is | |
1300 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1301 | * trying to access the should-be-closed file descriptors of a process | |
1302 | * undergoing exec(2). | |
1303 | */ | |
1304 | do_close_on_exec(current->files); | |
221af7f8 LT |
1305 | return 0; |
1306 | ||
1307 | out: | |
1308 | return retval; | |
1309 | } | |
1310 | EXPORT_SYMBOL(flush_old_exec); | |
1311 | ||
1b5d783c AV |
1312 | void would_dump(struct linux_binprm *bprm, struct file *file) |
1313 | { | |
f84df2a6 EB |
1314 | struct inode *inode = file_inode(file); |
1315 | if (inode_permission(inode, MAY_READ) < 0) { | |
1316 | struct user_namespace *old, *user_ns; | |
1b5d783c | 1317 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
f84df2a6 EB |
1318 | |
1319 | /* Ensure mm->user_ns contains the executable */ | |
1320 | user_ns = old = bprm->mm->user_ns; | |
1321 | while ((user_ns != &init_user_ns) && | |
1322 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1323 | user_ns = user_ns->parent; | |
1324 | ||
1325 | if (old != user_ns) { | |
1326 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1327 | put_user_ns(old); | |
1328 | } | |
1329 | } | |
1b5d783c AV |
1330 | } |
1331 | EXPORT_SYMBOL(would_dump); | |
1332 | ||
221af7f8 LT |
1333 | void setup_new_exec(struct linux_binprm * bprm) |
1334 | { | |
46d98eb4 KC |
1335 | /* |
1336 | * Once here, prepare_binrpm() will not be called any more, so | |
1337 | * the final state of setuid/setgid/fscaps can be merged into the | |
1338 | * secureexec flag. | |
1339 | */ | |
1340 | bprm->secureexec |= bprm->cap_elevated; | |
1341 | ||
64701dee | 1342 | if (bprm->secureexec) { |
fe8993b3 KC |
1343 | /* Make sure parent cannot signal privileged process. */ |
1344 | current->pdeath_signal = 0; | |
1345 | ||
64701dee KC |
1346 | /* |
1347 | * For secureexec, reset the stack limit to sane default to | |
1348 | * avoid bad behavior from the prior rlimits. This has to | |
1349 | * happen before arch_pick_mmap_layout(), which examines | |
1350 | * RLIMIT_STACK, but after the point of no return to avoid | |
779f4e1c | 1351 | * needing to clean up the change on failure. |
64701dee | 1352 | */ |
c31dbb14 KC |
1353 | if (bprm->rlim_stack.rlim_cur > _STK_LIM) |
1354 | bprm->rlim_stack.rlim_cur = _STK_LIM; | |
64701dee KC |
1355 | } |
1356 | ||
c31dbb14 | 1357 | arch_pick_mmap_layout(current->mm, &bprm->rlim_stack); |
1da177e4 | 1358 | |
1da177e4 LT |
1359 | current->sas_ss_sp = current->sas_ss_size = 0; |
1360 | ||
e816c201 KC |
1361 | /* |
1362 | * Figure out dumpability. Note that this checking only of current | |
1363 | * is wrong, but userspace depends on it. This should be testing | |
1364 | * bprm->secureexec instead. | |
1365 | */ | |
473d8963 | 1366 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || |
e816c201 KC |
1367 | !(uid_eq(current_euid(), current_uid()) && |
1368 | gid_eq(current_egid(), current_gid()))) | |
6c5d5238 | 1369 | set_dumpable(current->mm, suid_dumpable); |
473d8963 KC |
1370 | else |
1371 | set_dumpable(current->mm, SUID_DUMP_USER); | |
d6e71144 | 1372 | |
e9ea1e7f | 1373 | arch_setup_new_exec(); |
e041e328 | 1374 | perf_event_exec(); |
82b89778 | 1375 | __set_task_comm(current, kbasename(bprm->filename), true); |
1da177e4 | 1376 | |
0551fbd2 BH |
1377 | /* Set the new mm task size. We have to do that late because it may |
1378 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1379 | * some architectures like powerpc | |
1380 | */ | |
1381 | current->mm->task_size = TASK_SIZE; | |
1382 | ||
1da177e4 LT |
1383 | /* An exec changes our domain. We are no longer part of the thread |
1384 | group */ | |
1da177e4 | 1385 | current->self_exec_id++; |
1da177e4 | 1386 | flush_signal_handlers(current, 0); |
1da177e4 | 1387 | } |
221af7f8 | 1388 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1389 | |
b8383831 KC |
1390 | /* Runs immediately before start_thread() takes over. */ |
1391 | void finalize_exec(struct linux_binprm *bprm) | |
1392 | { | |
c31dbb14 KC |
1393 | /* Store any stack rlimit changes before starting thread. */ |
1394 | task_lock(current->group_leader); | |
1395 | current->signal->rlim[RLIMIT_STACK] = bprm->rlim_stack; | |
1396 | task_unlock(current->group_leader); | |
b8383831 KC |
1397 | } |
1398 | EXPORT_SYMBOL(finalize_exec); | |
1399 | ||
a2a8474c ON |
1400 | /* |
1401 | * Prepare credentials and lock ->cred_guard_mutex. | |
1402 | * install_exec_creds() commits the new creds and drops the lock. | |
1403 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1404 | * and unlock. | |
1405 | */ | |
4addd264 | 1406 | static int prepare_bprm_creds(struct linux_binprm *bprm) |
a2a8474c | 1407 | { |
9b1bf12d | 1408 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
a2a8474c ON |
1409 | return -ERESTARTNOINTR; |
1410 | ||
1411 | bprm->cred = prepare_exec_creds(); | |
1412 | if (likely(bprm->cred)) | |
1413 | return 0; | |
1414 | ||
9b1bf12d | 1415 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1416 | return -ENOMEM; |
1417 | } | |
1418 | ||
c4ad8f98 | 1419 | static void free_bprm(struct linux_binprm *bprm) |
a2a8474c ON |
1420 | { |
1421 | free_arg_pages(bprm); | |
1422 | if (bprm->cred) { | |
9b1bf12d | 1423 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1424 | abort_creds(bprm->cred); |
1425 | } | |
63e46b95 ON |
1426 | if (bprm->file) { |
1427 | allow_write_access(bprm->file); | |
1428 | fput(bprm->file); | |
1429 | } | |
b66c5984 KC |
1430 | /* If a binfmt changed the interp, free it. */ |
1431 | if (bprm->interp != bprm->filename) | |
1432 | kfree(bprm->interp); | |
a2a8474c ON |
1433 | kfree(bprm); |
1434 | } | |
1435 | ||
c2315c18 | 1436 | int bprm_change_interp(const char *interp, struct linux_binprm *bprm) |
b66c5984 KC |
1437 | { |
1438 | /* If a binfmt changed the interp, free it first. */ | |
1439 | if (bprm->interp != bprm->filename) | |
1440 | kfree(bprm->interp); | |
1441 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1442 | if (!bprm->interp) | |
1443 | return -ENOMEM; | |
1444 | return 0; | |
1445 | } | |
1446 | EXPORT_SYMBOL(bprm_change_interp); | |
1447 | ||
a6f76f23 DH |
1448 | /* |
1449 | * install the new credentials for this executable | |
1450 | */ | |
1451 | void install_exec_creds(struct linux_binprm *bprm) | |
1452 | { | |
1453 | security_bprm_committing_creds(bprm); | |
1454 | ||
1455 | commit_creds(bprm->cred); | |
1456 | bprm->cred = NULL; | |
2976b10f SE |
1457 | |
1458 | /* | |
1459 | * Disable monitoring for regular users | |
1460 | * when executing setuid binaries. Must | |
1461 | * wait until new credentials are committed | |
1462 | * by commit_creds() above | |
1463 | */ | |
1464 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1465 | perf_event_exit_task(current); | |
a2a8474c ON |
1466 | /* |
1467 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1468 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1469 | * credentials; any time after this it may be unlocked. |
1470 | */ | |
a6f76f23 | 1471 | security_bprm_committed_creds(bprm); |
9b1bf12d | 1472 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a6f76f23 DH |
1473 | } |
1474 | EXPORT_SYMBOL(install_exec_creds); | |
1475 | ||
1476 | /* | |
1477 | * determine how safe it is to execute the proposed program | |
9b1bf12d | 1478 | * - the caller must hold ->cred_guard_mutex to protect against |
c2e1f2e3 | 1479 | * PTRACE_ATTACH or seccomp thread-sync |
a6f76f23 | 1480 | */ |
9e00cdb0 | 1481 | static void check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1482 | { |
0bf2f3ae | 1483 | struct task_struct *p = current, *t; |
f1191b50 | 1484 | unsigned n_fs; |
a6f76f23 | 1485 | |
9227dd2a EB |
1486 | if (p->ptrace) |
1487 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
a6f76f23 | 1488 | |
259e5e6c AL |
1489 | /* |
1490 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1491 | * mess up. | |
1492 | */ | |
1d4457f9 | 1493 | if (task_no_new_privs(current)) |
259e5e6c AL |
1494 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
1495 | ||
83f62a2e | 1496 | t = p; |
0bf2f3ae | 1497 | n_fs = 1; |
2a4419b5 | 1498 | spin_lock(&p->fs->lock); |
437f7fdb | 1499 | rcu_read_lock(); |
83f62a2e | 1500 | while_each_thread(p, t) { |
0bf2f3ae DH |
1501 | if (t->fs == p->fs) |
1502 | n_fs++; | |
0bf2f3ae | 1503 | } |
437f7fdb | 1504 | rcu_read_unlock(); |
0bf2f3ae | 1505 | |
9e00cdb0 | 1506 | if (p->fs->users > n_fs) |
a6f76f23 | 1507 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
9e00cdb0 ON |
1508 | else |
1509 | p->fs->in_exec = 1; | |
2a4419b5 | 1510 | spin_unlock(&p->fs->lock); |
a6f76f23 DH |
1511 | } |
1512 | ||
8b01fc86 JH |
1513 | static void bprm_fill_uid(struct linux_binprm *bprm) |
1514 | { | |
1515 | struct inode *inode; | |
1516 | unsigned int mode; | |
1517 | kuid_t uid; | |
1518 | kgid_t gid; | |
1519 | ||
cb6fd68f KC |
1520 | /* |
1521 | * Since this can be called multiple times (via prepare_binprm), | |
1522 | * we must clear any previous work done when setting set[ug]id | |
1523 | * bits from any earlier bprm->file uses (for example when run | |
1524 | * first for a setuid script then again for its interpreter). | |
1525 | */ | |
8b01fc86 JH |
1526 | bprm->cred->euid = current_euid(); |
1527 | bprm->cred->egid = current_egid(); | |
1528 | ||
380cf5ba | 1529 | if (!mnt_may_suid(bprm->file->f_path.mnt)) |
8b01fc86 JH |
1530 | return; |
1531 | ||
1532 | if (task_no_new_privs(current)) | |
1533 | return; | |
1534 | ||
fea6d2a6 | 1535 | inode = bprm->file->f_path.dentry->d_inode; |
8b01fc86 JH |
1536 | mode = READ_ONCE(inode->i_mode); |
1537 | if (!(mode & (S_ISUID|S_ISGID))) | |
1538 | return; | |
1539 | ||
1540 | /* Be careful if suid/sgid is set */ | |
5955102c | 1541 | inode_lock(inode); |
8b01fc86 JH |
1542 | |
1543 | /* reload atomically mode/uid/gid now that lock held */ | |
1544 | mode = inode->i_mode; | |
1545 | uid = inode->i_uid; | |
1546 | gid = inode->i_gid; | |
5955102c | 1547 | inode_unlock(inode); |
8b01fc86 JH |
1548 | |
1549 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1550 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1551 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1552 | return; | |
1553 | ||
1554 | if (mode & S_ISUID) { | |
1555 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1556 | bprm->cred->euid = uid; | |
1557 | } | |
1558 | ||
1559 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1560 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1561 | bprm->cred->egid = gid; | |
1562 | } | |
1563 | } | |
1564 | ||
9e00cdb0 ON |
1565 | /* |
1566 | * Fill the binprm structure from the inode. | |
6eb3c3d0 | 1567 | * Check permissions, then read the first BINPRM_BUF_SIZE bytes |
a6f76f23 DH |
1568 | * |
1569 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1570 | */ |
1571 | int prepare_binprm(struct linux_binprm *bprm) | |
1572 | { | |
1da177e4 | 1573 | int retval; |
bdd1d2d3 | 1574 | loff_t pos = 0; |
1da177e4 | 1575 | |
8b01fc86 | 1576 | bprm_fill_uid(bprm); |
1da177e4 LT |
1577 | |
1578 | /* fill in binprm security blob */ | |
a6f76f23 | 1579 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1580 | if (retval) |
1581 | return retval; | |
ddb4a144 | 1582 | bprm->called_set_creds = 1; |
1da177e4 | 1583 | |
a6f76f23 | 1584 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
bdd1d2d3 | 1585 | return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos); |
1da177e4 LT |
1586 | } |
1587 | ||
1588 | EXPORT_SYMBOL(prepare_binprm); | |
1589 | ||
4fc75ff4 NP |
1590 | /* |
1591 | * Arguments are '\0' separated strings found at the location bprm->p | |
1592 | * points to; chop off the first by relocating brpm->p to right after | |
1593 | * the first '\0' encountered. | |
1594 | */ | |
b6a2fea3 | 1595 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1596 | { |
b6a2fea3 OW |
1597 | int ret = 0; |
1598 | unsigned long offset; | |
1599 | char *kaddr; | |
1600 | struct page *page; | |
4fc75ff4 | 1601 | |
b6a2fea3 OW |
1602 | if (!bprm->argc) |
1603 | return 0; | |
1da177e4 | 1604 | |
b6a2fea3 OW |
1605 | do { |
1606 | offset = bprm->p & ~PAGE_MASK; | |
1607 | page = get_arg_page(bprm, bprm->p, 0); | |
1608 | if (!page) { | |
1609 | ret = -EFAULT; | |
1610 | goto out; | |
1611 | } | |
e8e3c3d6 | 1612 | kaddr = kmap_atomic(page); |
4fc75ff4 | 1613 | |
b6a2fea3 OW |
1614 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1615 | offset++, bprm->p++) | |
1616 | ; | |
4fc75ff4 | 1617 | |
e8e3c3d6 | 1618 | kunmap_atomic(kaddr); |
b6a2fea3 | 1619 | put_arg_page(page); |
b6a2fea3 | 1620 | } while (offset == PAGE_SIZE); |
4fc75ff4 | 1621 | |
b6a2fea3 OW |
1622 | bprm->p++; |
1623 | bprm->argc--; | |
1624 | ret = 0; | |
4fc75ff4 | 1625 | |
b6a2fea3 OW |
1626 | out: |
1627 | return ret; | |
1da177e4 | 1628 | } |
1da177e4 LT |
1629 | EXPORT_SYMBOL(remove_arg_zero); |
1630 | ||
cb7b6b1c | 1631 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1da177e4 LT |
1632 | /* |
1633 | * cycle the list of binary formats handler, until one recognizes the image | |
1634 | */ | |
3c456bfc | 1635 | int search_binary_handler(struct linux_binprm *bprm) |
1da177e4 | 1636 | { |
cb7b6b1c | 1637 | bool need_retry = IS_ENABLED(CONFIG_MODULES); |
1da177e4 | 1638 | struct linux_binfmt *fmt; |
cb7b6b1c | 1639 | int retval; |
1da177e4 | 1640 | |
d7402698 | 1641 | /* This allows 4 levels of binfmt rewrites before failing hard. */ |
131b2f9f | 1642 | if (bprm->recursion_depth > 5) |
d7402698 KC |
1643 | return -ELOOP; |
1644 | ||
1da177e4 LT |
1645 | retval = security_bprm_check(bprm); |
1646 | if (retval) | |
1647 | return retval; | |
1648 | ||
1da177e4 | 1649 | retval = -ENOENT; |
cb7b6b1c ON |
1650 | retry: |
1651 | read_lock(&binfmt_lock); | |
1652 | list_for_each_entry(fmt, &formats, lh) { | |
1653 | if (!try_module_get(fmt->module)) | |
1654 | continue; | |
1655 | read_unlock(&binfmt_lock); | |
d53ddd01 | 1656 | |
cb7b6b1c ON |
1657 | bprm->recursion_depth++; |
1658 | retval = fmt->load_binary(bprm); | |
d53ddd01 AD |
1659 | bprm->recursion_depth--; |
1660 | ||
19d860a1 AV |
1661 | read_lock(&binfmt_lock); |
1662 | put_binfmt(fmt); | |
19d860a1 AV |
1663 | if (retval < 0 && !bprm->mm) { |
1664 | /* we got to flush_old_exec() and failed after it */ | |
1665 | read_unlock(&binfmt_lock); | |
cb44c9a0 | 1666 | force_sigsegv(SIGSEGV); |
19d860a1 AV |
1667 | return retval; |
1668 | } | |
1669 | if (retval != -ENOEXEC || !bprm->file) { | |
1670 | read_unlock(&binfmt_lock); | |
cb7b6b1c | 1671 | return retval; |
1da177e4 | 1672 | } |
1da177e4 | 1673 | } |
cb7b6b1c ON |
1674 | read_unlock(&binfmt_lock); |
1675 | ||
19d860a1 | 1676 | if (need_retry) { |
cb7b6b1c ON |
1677 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && |
1678 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1679 | return retval; | |
4e0621a0 ON |
1680 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) |
1681 | return retval; | |
cb7b6b1c ON |
1682 | need_retry = false; |
1683 | goto retry; | |
1684 | } | |
1685 | ||
1da177e4 LT |
1686 | return retval; |
1687 | } | |
1da177e4 LT |
1688 | EXPORT_SYMBOL(search_binary_handler); |
1689 | ||
5d1baf3b ON |
1690 | static int exec_binprm(struct linux_binprm *bprm) |
1691 | { | |
1692 | pid_t old_pid, old_vpid; | |
1693 | int ret; | |
1694 | ||
1695 | /* Need to fetch pid before load_binary changes it */ | |
1696 | old_pid = current->pid; | |
1697 | rcu_read_lock(); | |
1698 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1699 | rcu_read_unlock(); | |
1700 | ||
1701 | ret = search_binary_handler(bprm); | |
1702 | if (ret >= 0) { | |
3eaded86 | 1703 | audit_bprm(bprm); |
5d1baf3b ON |
1704 | trace_sched_process_exec(current, old_pid, bprm); |
1705 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
9beb266f | 1706 | proc_exec_connector(current); |
5d1baf3b ON |
1707 | } |
1708 | ||
1709 | return ret; | |
1710 | } | |
1711 | ||
1da177e4 LT |
1712 | /* |
1713 | * sys_execve() executes a new program. | |
1714 | */ | |
449325b5 AS |
1715 | static int __do_execve_file(int fd, struct filename *filename, |
1716 | struct user_arg_ptr argv, | |
1717 | struct user_arg_ptr envp, | |
1718 | int flags, struct file *file) | |
1da177e4 | 1719 | { |
51f39a1f | 1720 | char *pathbuf = NULL; |
1da177e4 | 1721 | struct linux_binprm *bprm; |
3b125388 | 1722 | struct files_struct *displaced; |
1da177e4 | 1723 | int retval; |
72fa5997 | 1724 | |
c4ad8f98 LT |
1725 | if (IS_ERR(filename)) |
1726 | return PTR_ERR(filename); | |
1727 | ||
72fa5997 VK |
1728 | /* |
1729 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1730 | * set*uid() to execve() because too many poorly written programs | |
1731 | * don't check setuid() return code. Here we additionally recheck | |
1732 | * whether NPROC limit is still exceeded. | |
1733 | */ | |
1734 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
bd9d43f4 | 1735 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { |
72fa5997 VK |
1736 | retval = -EAGAIN; |
1737 | goto out_ret; | |
1738 | } | |
1739 | ||
1740 | /* We're below the limit (still or again), so we don't want to make | |
1741 | * further execve() calls fail. */ | |
1742 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1da177e4 | 1743 | |
3b125388 | 1744 | retval = unshare_files(&displaced); |
fd8328be AV |
1745 | if (retval) |
1746 | goto out_ret; | |
1747 | ||
1da177e4 | 1748 | retval = -ENOMEM; |
11b0b5ab | 1749 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1750 | if (!bprm) |
fd8328be | 1751 | goto out_files; |
1da177e4 | 1752 | |
a2a8474c ON |
1753 | retval = prepare_bprm_creds(bprm); |
1754 | if (retval) | |
a6f76f23 | 1755 | goto out_free; |
498052bb | 1756 | |
9e00cdb0 | 1757 | check_unsafe_exec(bprm); |
a2a8474c | 1758 | current->in_execve = 1; |
a6f76f23 | 1759 | |
449325b5 AS |
1760 | if (!file) |
1761 | file = do_open_execat(fd, filename, flags); | |
1da177e4 LT |
1762 | retval = PTR_ERR(file); |
1763 | if (IS_ERR(file)) | |
498052bb | 1764 | goto out_unmark; |
1da177e4 LT |
1765 | |
1766 | sched_exec(); | |
1767 | ||
1da177e4 | 1768 | bprm->file = file; |
449325b5 AS |
1769 | if (!filename) { |
1770 | bprm->filename = "none"; | |
1771 | } else if (fd == AT_FDCWD || filename->name[0] == '/') { | |
51f39a1f DD |
1772 | bprm->filename = filename->name; |
1773 | } else { | |
1774 | if (filename->name[0] == '\0') | |
0ee931c4 | 1775 | pathbuf = kasprintf(GFP_KERNEL, "/dev/fd/%d", fd); |
51f39a1f | 1776 | else |
0ee931c4 | 1777 | pathbuf = kasprintf(GFP_KERNEL, "/dev/fd/%d/%s", |
51f39a1f DD |
1778 | fd, filename->name); |
1779 | if (!pathbuf) { | |
1780 | retval = -ENOMEM; | |
1781 | goto out_unmark; | |
1782 | } | |
1783 | /* | |
1784 | * Record that a name derived from an O_CLOEXEC fd will be | |
1785 | * inaccessible after exec. Relies on having exclusive access to | |
1786 | * current->files (due to unshare_files above). | |
1787 | */ | |
1788 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1789 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1790 | bprm->filename = pathbuf; | |
1791 | } | |
1792 | bprm->interp = bprm->filename; | |
1da177e4 | 1793 | |
b6a2fea3 OW |
1794 | retval = bprm_mm_init(bprm); |
1795 | if (retval) | |
63e46b95 | 1796 | goto out_unmark; |
1da177e4 | 1797 | |
655c16a8 ON |
1798 | retval = prepare_arg_pages(bprm, argv, envp); |
1799 | if (retval < 0) | |
1da177e4 LT |
1800 | goto out; |
1801 | ||
1802 | retval = prepare_binprm(bprm); | |
1803 | if (retval < 0) | |
1804 | goto out; | |
1805 | ||
1806 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1807 | if (retval < 0) | |
1808 | goto out; | |
1809 | ||
1810 | bprm->exec = bprm->p; | |
1811 | retval = copy_strings(bprm->envc, envp, bprm); | |
1812 | if (retval < 0) | |
1813 | goto out; | |
1814 | ||
1815 | retval = copy_strings(bprm->argc, argv, bprm); | |
1816 | if (retval < 0) | |
1817 | goto out; | |
1818 | ||
f84df2a6 EB |
1819 | would_dump(bprm, bprm->file); |
1820 | ||
5d1baf3b | 1821 | retval = exec_binprm(bprm); |
a6f76f23 DH |
1822 | if (retval < 0) |
1823 | goto out; | |
1da177e4 | 1824 | |
a6f76f23 | 1825 | /* execve succeeded */ |
498052bb | 1826 | current->fs->in_exec = 0; |
f9ce1f1c | 1827 | current->in_execve = 0; |
d7822b1e | 1828 | rseq_execve(current); |
a6f76f23 | 1829 | acct_update_integrals(current); |
16d51a59 | 1830 | task_numa_free(current, false); |
a6f76f23 | 1831 | free_bprm(bprm); |
51f39a1f | 1832 | kfree(pathbuf); |
449325b5 AS |
1833 | if (filename) |
1834 | putname(filename); | |
a6f76f23 DH |
1835 | if (displaced) |
1836 | put_files_struct(displaced); | |
1837 | return retval; | |
1da177e4 | 1838 | |
a6f76f23 | 1839 | out: |
3c77f845 ON |
1840 | if (bprm->mm) { |
1841 | acct_arg_size(bprm, 0); | |
1842 | mmput(bprm->mm); | |
1843 | } | |
1da177e4 | 1844 | |
498052bb | 1845 | out_unmark: |
9e00cdb0 | 1846 | current->fs->in_exec = 0; |
f9ce1f1c | 1847 | current->in_execve = 0; |
a6f76f23 DH |
1848 | |
1849 | out_free: | |
08a6fac1 | 1850 | free_bprm(bprm); |
51f39a1f | 1851 | kfree(pathbuf); |
1da177e4 | 1852 | |
fd8328be | 1853 | out_files: |
3b125388 AV |
1854 | if (displaced) |
1855 | reset_files_struct(displaced); | |
1da177e4 | 1856 | out_ret: |
449325b5 AS |
1857 | if (filename) |
1858 | putname(filename); | |
1da177e4 LT |
1859 | return retval; |
1860 | } | |
1861 | ||
449325b5 AS |
1862 | static int do_execveat_common(int fd, struct filename *filename, |
1863 | struct user_arg_ptr argv, | |
1864 | struct user_arg_ptr envp, | |
1865 | int flags) | |
1866 | { | |
1867 | return __do_execve_file(fd, filename, argv, envp, flags, NULL); | |
1868 | } | |
1869 | ||
1870 | int do_execve_file(struct file *file, void *__argv, void *__envp) | |
1871 | { | |
1872 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1873 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1874 | ||
1875 | return __do_execve_file(AT_FDCWD, NULL, argv, envp, 0, file); | |
1876 | } | |
1877 | ||
c4ad8f98 | 1878 | int do_execve(struct filename *filename, |
ba2d0162 | 1879 | const char __user *const __user *__argv, |
da3d4c5f | 1880 | const char __user *const __user *__envp) |
ba2d0162 | 1881 | { |
0e028465 ON |
1882 | struct user_arg_ptr argv = { .ptr.native = __argv }; |
1883 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
51f39a1f DD |
1884 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1885 | } | |
1886 | ||
1887 | int do_execveat(int fd, struct filename *filename, | |
1888 | const char __user *const __user *__argv, | |
1889 | const char __user *const __user *__envp, | |
1890 | int flags) | |
1891 | { | |
1892 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1893 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1894 | ||
1895 | return do_execveat_common(fd, filename, argv, envp, flags); | |
0e028465 ON |
1896 | } |
1897 | ||
1898 | #ifdef CONFIG_COMPAT | |
c4ad8f98 | 1899 | static int compat_do_execve(struct filename *filename, |
38b983b3 | 1900 | const compat_uptr_t __user *__argv, |
d03d26e5 | 1901 | const compat_uptr_t __user *__envp) |
0e028465 ON |
1902 | { |
1903 | struct user_arg_ptr argv = { | |
1904 | .is_compat = true, | |
1905 | .ptr.compat = __argv, | |
1906 | }; | |
1907 | struct user_arg_ptr envp = { | |
1908 | .is_compat = true, | |
1909 | .ptr.compat = __envp, | |
1910 | }; | |
51f39a1f DD |
1911 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1912 | } | |
1913 | ||
1914 | static int compat_do_execveat(int fd, struct filename *filename, | |
1915 | const compat_uptr_t __user *__argv, | |
1916 | const compat_uptr_t __user *__envp, | |
1917 | int flags) | |
1918 | { | |
1919 | struct user_arg_ptr argv = { | |
1920 | .is_compat = true, | |
1921 | .ptr.compat = __argv, | |
1922 | }; | |
1923 | struct user_arg_ptr envp = { | |
1924 | .is_compat = true, | |
1925 | .ptr.compat = __envp, | |
1926 | }; | |
1927 | return do_execveat_common(fd, filename, argv, envp, flags); | |
ba2d0162 | 1928 | } |
0e028465 | 1929 | #endif |
ba2d0162 | 1930 | |
964ee7df | 1931 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1932 | { |
801460d0 HS |
1933 | struct mm_struct *mm = current->mm; |
1934 | ||
1935 | if (mm->binfmt) | |
1936 | module_put(mm->binfmt->module); | |
1da177e4 | 1937 | |
801460d0 | 1938 | mm->binfmt = new; |
964ee7df ON |
1939 | if (new) |
1940 | __module_get(new->module); | |
1da177e4 | 1941 | } |
1da177e4 LT |
1942 | EXPORT_SYMBOL(set_binfmt); |
1943 | ||
6c5d5238 | 1944 | /* |
7288e118 | 1945 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. |
6c5d5238 KH |
1946 | */ |
1947 | void set_dumpable(struct mm_struct *mm, int value) | |
1948 | { | |
7288e118 ON |
1949 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) |
1950 | return; | |
1951 | ||
26e15225 | 1952 | set_mask_bits(&mm->flags, MMF_DUMPABLE_MASK, value); |
6c5d5238 | 1953 | } |
6c5d5238 | 1954 | |
38b983b3 AV |
1955 | SYSCALL_DEFINE3(execve, |
1956 | const char __user *, filename, | |
1957 | const char __user *const __user *, argv, | |
1958 | const char __user *const __user *, envp) | |
1959 | { | |
c4ad8f98 | 1960 | return do_execve(getname(filename), argv, envp); |
38b983b3 | 1961 | } |
51f39a1f DD |
1962 | |
1963 | SYSCALL_DEFINE5(execveat, | |
1964 | int, fd, const char __user *, filename, | |
1965 | const char __user *const __user *, argv, | |
1966 | const char __user *const __user *, envp, | |
1967 | int, flags) | |
1968 | { | |
1969 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1970 | ||
1971 | return do_execveat(fd, | |
1972 | getname_flags(filename, lookup_flags, NULL), | |
1973 | argv, envp, flags); | |
1974 | } | |
1975 | ||
38b983b3 | 1976 | #ifdef CONFIG_COMPAT |
625b1d7e HC |
1977 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, |
1978 | const compat_uptr_t __user *, argv, | |
1979 | const compat_uptr_t __user *, envp) | |
38b983b3 | 1980 | { |
c4ad8f98 | 1981 | return compat_do_execve(getname(filename), argv, envp); |
38b983b3 | 1982 | } |
51f39a1f DD |
1983 | |
1984 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1985 | const char __user *, filename, | |
1986 | const compat_uptr_t __user *, argv, | |
1987 | const compat_uptr_t __user *, envp, | |
1988 | int, flags) | |
1989 | { | |
1990 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1991 | ||
1992 | return compat_do_execveat(fd, | |
1993 | getname_flags(filename, lookup_flags, NULL), | |
1994 | argv, envp, flags); | |
1995 | } | |
38b983b3 | 1996 | #endif |