]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | |
613cc2b6 | 22 | * formats. |
1da177e4 LT |
23 | */ |
24 | ||
1da177e4 LT |
25 | #include <linux/slab.h> |
26 | #include <linux/file.h> | |
9f3acc31 | 27 | #include <linux/fdtable.h> |
ba92a43d | 28 | #include <linux/mm.h> |
615d6e87 | 29 | #include <linux/vmacache.h> |
1da177e4 LT |
30 | #include <linux/stat.h> |
31 | #include <linux/fcntl.h> | |
ba92a43d | 32 | #include <linux/swap.h> |
74aadce9 | 33 | #include <linux/string.h> |
1da177e4 | 34 | #include <linux/init.h> |
6e84f315 | 35 | #include <linux/sched/mm.h> |
f7ccbae4 | 36 | #include <linux/sched/coredump.h> |
3f07c014 | 37 | #include <linux/sched/signal.h> |
6a3827d7 | 38 | #include <linux/sched/numa_balancing.h> |
29930025 | 39 | #include <linux/sched/task.h> |
ca5b172b | 40 | #include <linux/pagemap.h> |
cdd6c482 | 41 | #include <linux/perf_event.h> |
1da177e4 LT |
42 | #include <linux/highmem.h> |
43 | #include <linux/spinlock.h> | |
44 | #include <linux/key.h> | |
45 | #include <linux/personality.h> | |
46 | #include <linux/binfmts.h> | |
1da177e4 | 47 | #include <linux/utsname.h> |
84d73786 | 48 | #include <linux/pid_namespace.h> |
1da177e4 LT |
49 | #include <linux/module.h> |
50 | #include <linux/namei.h> | |
1da177e4 LT |
51 | #include <linux/mount.h> |
52 | #include <linux/security.h> | |
53 | #include <linux/syscalls.h> | |
8f0ab514 | 54 | #include <linux/tsacct_kern.h> |
9f46080c | 55 | #include <linux/cn_proc.h> |
473ae30b | 56 | #include <linux/audit.h> |
6341c393 | 57 | #include <linux/tracehook.h> |
5f4123be | 58 | #include <linux/kmod.h> |
6110e3ab | 59 | #include <linux/fsnotify.h> |
5ad4e53b | 60 | #include <linux/fs_struct.h> |
61be228a | 61 | #include <linux/pipe_fs_i.h> |
3d5992d2 | 62 | #include <linux/oom.h> |
0e028465 | 63 | #include <linux/compat.h> |
b44a7dfc | 64 | #include <linux/vmalloc.h> |
4d7b698b | 65 | #include <linux/delay.h> |
1da177e4 | 66 | |
308a1eef SJR |
67 | #include <trace/events/fs.h> |
68 | ||
7c0f6ba6 | 69 | #include <linux/uaccess.h> |
1da177e4 | 70 | #include <asm/mmu_context.h> |
b6a2fea3 | 71 | #include <asm/tlb.h> |
43d2b113 KH |
72 | |
73 | #include <trace/events/task.h> | |
a6f76f23 | 74 | #include "internal.h" |
1da177e4 | 75 | |
4ff16c25 DS |
76 | #include <trace/events/sched.h> |
77 | ||
d6e71144 AC |
78 | int suid_dumpable = 0; |
79 | ||
e4dc1b14 | 80 | static LIST_HEAD(formats); |
1da177e4 LT |
81 | static DEFINE_RWLOCK(binfmt_lock); |
82 | ||
8fc3dc5a | 83 | void __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 84 | { |
8fc3dc5a | 85 | BUG_ON(!fmt); |
92eaa565 ON |
86 | if (WARN_ON(!fmt->load_binary)) |
87 | return; | |
1da177e4 | 88 | write_lock(&binfmt_lock); |
74641f58 IK |
89 | insert ? list_add(&fmt->lh, &formats) : |
90 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 | 91 | write_unlock(&binfmt_lock); |
1da177e4 LT |
92 | } |
93 | ||
74641f58 | 94 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 95 | |
f6b450d4 | 96 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 97 | { |
1da177e4 | 98 | write_lock(&binfmt_lock); |
e4dc1b14 | 99 | list_del(&fmt->lh); |
1da177e4 | 100 | write_unlock(&binfmt_lock); |
1da177e4 LT |
101 | } |
102 | ||
103 | EXPORT_SYMBOL(unregister_binfmt); | |
104 | ||
105 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
106 | { | |
107 | module_put(fmt->module); | |
108 | } | |
109 | ||
90f8572b EB |
110 | bool path_noexec(const struct path *path) |
111 | { | |
112 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
113 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
114 | } | |
b6450630 | 115 | EXPORT_SYMBOL_GPL(path_noexec); |
90f8572b | 116 | |
0dc04886 SF |
117 | bool path_nosuid(const struct path *path) |
118 | { | |
119 | return !mnt_may_suid(path->mnt) || | |
120 | (path->mnt->mnt_sb->s_iflags & SB_I_NOSUID); | |
121 | } | |
122 | EXPORT_SYMBOL(path_nosuid); | |
123 | ||
69369a70 | 124 | #ifdef CONFIG_USELIB |
1da177e4 LT |
125 | /* |
126 | * Note that a shared library must be both readable and executable due to | |
127 | * security reasons. | |
128 | * | |
129 | * Also note that we take the address to load from from the file itself. | |
130 | */ | |
1e7bfb21 | 131 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 132 | { |
72c2d531 | 133 | struct linux_binfmt *fmt; |
964bd183 | 134 | struct file *file; |
91a27b2a | 135 | struct filename *tmp = getname(library); |
964bd183 | 136 | int error = PTR_ERR(tmp); |
47c805dc AV |
137 | static const struct open_flags uselib_flags = { |
138 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
62fb4a15 | 139 | .acc_mode = MAY_READ | MAY_EXEC, |
f9652e10 AV |
140 | .intent = LOOKUP_OPEN, |
141 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 142 | }; |
964bd183 | 143 | |
6e8341a1 AV |
144 | if (IS_ERR(tmp)) |
145 | goto out; | |
146 | ||
f9652e10 | 147 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); |
6e8341a1 AV |
148 | putname(tmp); |
149 | error = PTR_ERR(file); | |
150 | if (IS_ERR(file)) | |
1da177e4 LT |
151 | goto out; |
152 | ||
153 | error = -EINVAL; | |
496ad9aa | 154 | if (!S_ISREG(file_inode(file)->i_mode)) |
1da177e4 LT |
155 | goto exit; |
156 | ||
30524472 | 157 | error = -EACCES; |
90f8572b | 158 | if (path_noexec(&file->f_path)) |
1da177e4 LT |
159 | goto exit; |
160 | ||
2a12a9d7 | 161 | fsnotify_open(file); |
6110e3ab | 162 | |
1da177e4 | 163 | error = -ENOEXEC; |
1da177e4 | 164 | |
72c2d531 AV |
165 | read_lock(&binfmt_lock); |
166 | list_for_each_entry(fmt, &formats, lh) { | |
167 | if (!fmt->load_shlib) | |
168 | continue; | |
169 | if (!try_module_get(fmt->module)) | |
170 | continue; | |
1da177e4 | 171 | read_unlock(&binfmt_lock); |
72c2d531 AV |
172 | error = fmt->load_shlib(file); |
173 | read_lock(&binfmt_lock); | |
174 | put_binfmt(fmt); | |
175 | if (error != -ENOEXEC) | |
176 | break; | |
1da177e4 | 177 | } |
72c2d531 | 178 | read_unlock(&binfmt_lock); |
6e8341a1 | 179 | exit: |
1da177e4 LT |
180 | fput(file); |
181 | out: | |
182 | return error; | |
1da177e4 | 183 | } |
69369a70 | 184 | #endif /* #ifdef CONFIG_USELIB */ |
1da177e4 | 185 | |
b6a2fea3 | 186 | #ifdef CONFIG_MMU |
ae6b585e ON |
187 | /* |
188 | * The nascent bprm->mm is not visible until exec_mmap() but it can | |
189 | * use a lot of memory, account these pages in current->mm temporary | |
190 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we | |
191 | * change the counter back via acct_arg_size(0). | |
192 | */ | |
0e028465 | 193 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
194 | { |
195 | struct mm_struct *mm = current->mm; | |
196 | long diff = (long)(pages - bprm->vma_pages); | |
197 | ||
198 | if (!mm || !diff) | |
199 | return; | |
200 | ||
201 | bprm->vma_pages = pages; | |
3c77f845 | 202 | add_mm_counter(mm, MM_ANONPAGES, diff); |
3c77f845 ON |
203 | } |
204 | ||
0e028465 | 205 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
206 | int write) |
207 | { | |
208 | struct page *page; | |
209 | int ret; | |
9beae1ea | 210 | unsigned int gup_flags = FOLL_FORCE; |
b6a2fea3 OW |
211 | |
212 | #ifdef CONFIG_STACK_GROWSUP | |
213 | if (write) { | |
d05f3169 | 214 | ret = expand_downwards(bprm->vma, pos); |
b6a2fea3 OW |
215 | if (ret < 0) |
216 | return NULL; | |
217 | } | |
218 | #endif | |
9beae1ea LS |
219 | |
220 | if (write) | |
221 | gup_flags |= FOLL_WRITE; | |
222 | ||
1e987790 DH |
223 | /* |
224 | * We are doing an exec(). 'current' is the process | |
225 | * doing the exec and bprm->mm is the new process's mm. | |
226 | */ | |
9beae1ea | 227 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, |
5b56d49f | 228 | &page, NULL, NULL); |
b6a2fea3 OW |
229 | if (ret <= 0) |
230 | return NULL; | |
231 | ||
232 | if (write) { | |
b6a2fea3 | 233 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
da029c11 | 234 | unsigned long ptr_size, limit; |
a64e715f | 235 | |
98da7d08 KC |
236 | /* |
237 | * Since the stack will hold pointers to the strings, we | |
238 | * must account for them as well. | |
239 | * | |
240 | * The size calculation is the entire vma while each arg page is | |
241 | * built, so each time we get here it's calculating how far it | |
242 | * is currently (rather than each call being just the newly | |
243 | * added size from the arg page). As a result, we need to | |
244 | * always add the entire size of the pointers, so that on the | |
245 | * last call to get_arg_page() we'll actually have the entire | |
246 | * correct size. | |
247 | */ | |
248 | ptr_size = (bprm->argc + bprm->envc) * sizeof(void *); | |
249 | if (ptr_size > ULONG_MAX - size) | |
250 | goto fail; | |
251 | size += ptr_size; | |
252 | ||
3c77f845 ON |
253 | acct_arg_size(bprm, size / PAGE_SIZE); |
254 | ||
a64e715f LT |
255 | /* |
256 | * We've historically supported up to 32 pages (ARG_MAX) | |
257 | * of argument strings even with small stacks | |
258 | */ | |
259 | if (size <= ARG_MAX) | |
260 | return page; | |
b6a2fea3 OW |
261 | |
262 | /* | |
da029c11 KC |
263 | * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM |
264 | * (whichever is smaller) for the argv+env strings. | |
b6a2fea3 OW |
265 | * This ensures that: |
266 | * - the remaining binfmt code will not run out of stack space, | |
267 | * - the program will have a reasonable amount of stack left | |
268 | * to work from. | |
269 | */ | |
da029c11 KC |
270 | limit = _STK_LIM / 4 * 3; |
271 | limit = min(limit, rlimit(RLIMIT_STACK) / 4); | |
272 | if (size > limit) | |
98da7d08 | 273 | goto fail; |
b6a2fea3 OW |
274 | } |
275 | ||
276 | return page; | |
98da7d08 KC |
277 | |
278 | fail: | |
279 | put_page(page); | |
280 | return NULL; | |
b6a2fea3 OW |
281 | } |
282 | ||
283 | static void put_arg_page(struct page *page) | |
284 | { | |
285 | put_page(page); | |
286 | } | |
287 | ||
b6a2fea3 OW |
288 | static void free_arg_pages(struct linux_binprm *bprm) |
289 | { | |
290 | } | |
291 | ||
292 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
293 | struct page *page) | |
294 | { | |
295 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
296 | } | |
297 | ||
298 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
299 | { | |
eaccbfa5 | 300 | int err; |
b6a2fea3 OW |
301 | struct vm_area_struct *vma = NULL; |
302 | struct mm_struct *mm = bprm->mm; | |
303 | ||
304 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
305 | if (!vma) | |
eaccbfa5 | 306 | return -ENOMEM; |
b6a2fea3 | 307 | |
f268dfe9 MH |
308 | if (down_write_killable(&mm->mmap_sem)) { |
309 | err = -EINTR; | |
310 | goto err_free; | |
311 | } | |
b6a2fea3 OW |
312 | vma->vm_mm = mm; |
313 | ||
314 | /* | |
315 | * Place the stack at the largest stack address the architecture | |
316 | * supports. Later, we'll move this to an appropriate place. We don't | |
317 | * use STACK_TOP because that can depend on attributes which aren't | |
318 | * configured yet. | |
319 | */ | |
aacb3d17 | 320 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
321 | vma->vm_end = STACK_TOP_MAX; |
322 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
d9104d1c | 323 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 324 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
5beb4930 | 325 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
462e635e | 326 | |
b6a2fea3 | 327 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 328 | if (err) |
b6a2fea3 | 329 | goto err; |
b6a2fea3 OW |
330 | |
331 | mm->stack_vm = mm->total_vm = 1; | |
fe3d197f | 332 | arch_bprm_mm_init(mm, vma); |
b6a2fea3 | 333 | up_write(&mm->mmap_sem); |
b6a2fea3 | 334 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 335 | return 0; |
b6a2fea3 | 336 | err: |
eaccbfa5 | 337 | up_write(&mm->mmap_sem); |
f268dfe9 | 338 | err_free: |
eaccbfa5 LFC |
339 | bprm->vma = NULL; |
340 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
341 | return err; |
342 | } | |
343 | ||
344 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
345 | { | |
346 | return len <= MAX_ARG_STRLEN; | |
347 | } | |
348 | ||
349 | #else | |
350 | ||
0e028465 | 351 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
352 | { |
353 | } | |
354 | ||
0e028465 | 355 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
356 | int write) |
357 | { | |
358 | struct page *page; | |
359 | ||
360 | page = bprm->page[pos / PAGE_SIZE]; | |
361 | if (!page && write) { | |
362 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
363 | if (!page) | |
364 | return NULL; | |
365 | bprm->page[pos / PAGE_SIZE] = page; | |
366 | } | |
367 | ||
368 | return page; | |
369 | } | |
370 | ||
371 | static void put_arg_page(struct page *page) | |
372 | { | |
373 | } | |
374 | ||
375 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
376 | { | |
377 | if (bprm->page[i]) { | |
378 | __free_page(bprm->page[i]); | |
379 | bprm->page[i] = NULL; | |
380 | } | |
381 | } | |
382 | ||
383 | static void free_arg_pages(struct linux_binprm *bprm) | |
384 | { | |
385 | int i; | |
386 | ||
387 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
388 | free_arg_page(bprm, i); | |
389 | } | |
390 | ||
391 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
392 | struct page *page) | |
393 | { | |
394 | } | |
395 | ||
396 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
397 | { | |
398 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
399 | return 0; | |
400 | } | |
401 | ||
402 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
403 | { | |
404 | return len <= bprm->p; | |
405 | } | |
406 | ||
407 | #endif /* CONFIG_MMU */ | |
408 | ||
409 | /* | |
410 | * Create a new mm_struct and populate it with a temporary stack | |
411 | * vm_area_struct. We don't have enough context at this point to set the stack | |
412 | * flags, permissions, and offset, so we use temporary values. We'll update | |
413 | * them later in setup_arg_pages(). | |
414 | */ | |
9cc64cea | 415 | static int bprm_mm_init(struct linux_binprm *bprm) |
b6a2fea3 OW |
416 | { |
417 | int err; | |
418 | struct mm_struct *mm = NULL; | |
419 | ||
420 | bprm->mm = mm = mm_alloc(); | |
421 | err = -ENOMEM; | |
422 | if (!mm) | |
423 | goto err; | |
424 | ||
b6a2fea3 OW |
425 | err = __bprm_mm_init(bprm); |
426 | if (err) | |
427 | goto err; | |
428 | ||
429 | return 0; | |
430 | ||
431 | err: | |
432 | if (mm) { | |
433 | bprm->mm = NULL; | |
434 | mmdrop(mm); | |
435 | } | |
436 | ||
437 | return err; | |
438 | } | |
439 | ||
ba2d0162 | 440 | struct user_arg_ptr { |
0e028465 ON |
441 | #ifdef CONFIG_COMPAT |
442 | bool is_compat; | |
443 | #endif | |
444 | union { | |
445 | const char __user *const __user *native; | |
446 | #ifdef CONFIG_COMPAT | |
38b983b3 | 447 | const compat_uptr_t __user *compat; |
0e028465 ON |
448 | #endif |
449 | } ptr; | |
ba2d0162 ON |
450 | }; |
451 | ||
452 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
1d1dbf81 | 453 | { |
0e028465 ON |
454 | const char __user *native; |
455 | ||
456 | #ifdef CONFIG_COMPAT | |
457 | if (unlikely(argv.is_compat)) { | |
458 | compat_uptr_t compat; | |
459 | ||
460 | if (get_user(compat, argv.ptr.compat + nr)) | |
461 | return ERR_PTR(-EFAULT); | |
1d1dbf81 | 462 | |
0e028465 ON |
463 | return compat_ptr(compat); |
464 | } | |
465 | #endif | |
466 | ||
467 | if (get_user(native, argv.ptr.native + nr)) | |
1d1dbf81 ON |
468 | return ERR_PTR(-EFAULT); |
469 | ||
0e028465 | 470 | return native; |
1d1dbf81 ON |
471 | } |
472 | ||
1da177e4 LT |
473 | /* |
474 | * count() counts the number of strings in array ARGV. | |
475 | */ | |
ba2d0162 | 476 | static int count(struct user_arg_ptr argv, int max) |
1da177e4 LT |
477 | { |
478 | int i = 0; | |
479 | ||
0e028465 | 480 | if (argv.ptr.native != NULL) { |
1da177e4 | 481 | for (;;) { |
1d1dbf81 | 482 | const char __user *p = get_user_arg_ptr(argv, i); |
1da177e4 | 483 | |
1da177e4 LT |
484 | if (!p) |
485 | break; | |
1d1dbf81 ON |
486 | |
487 | if (IS_ERR(p)) | |
488 | return -EFAULT; | |
489 | ||
6d92d4f6 | 490 | if (i >= max) |
1da177e4 | 491 | return -E2BIG; |
6d92d4f6 | 492 | ++i; |
9aea5a65 RM |
493 | |
494 | if (fatal_signal_pending(current)) | |
495 | return -ERESTARTNOHAND; | |
1da177e4 LT |
496 | cond_resched(); |
497 | } | |
498 | } | |
499 | return i; | |
500 | } | |
501 | ||
502 | /* | |
b6a2fea3 OW |
503 | * 'copy_strings()' copies argument/environment strings from the old |
504 | * processes's memory to the new process's stack. The call to get_user_pages() | |
505 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 506 | */ |
ba2d0162 | 507 | static int copy_strings(int argc, struct user_arg_ptr argv, |
75c96f85 | 508 | struct linux_binprm *bprm) |
1da177e4 LT |
509 | { |
510 | struct page *kmapped_page = NULL; | |
511 | char *kaddr = NULL; | |
b6a2fea3 | 512 | unsigned long kpos = 0; |
1da177e4 LT |
513 | int ret; |
514 | ||
515 | while (argc-- > 0) { | |
d7627467 | 516 | const char __user *str; |
1da177e4 LT |
517 | int len; |
518 | unsigned long pos; | |
519 | ||
1d1dbf81 ON |
520 | ret = -EFAULT; |
521 | str = get_user_arg_ptr(argv, argc); | |
522 | if (IS_ERR(str)) | |
1da177e4 | 523 | goto out; |
1da177e4 | 524 | |
1d1dbf81 ON |
525 | len = strnlen_user(str, MAX_ARG_STRLEN); |
526 | if (!len) | |
527 | goto out; | |
528 | ||
529 | ret = -E2BIG; | |
530 | if (!valid_arg_len(bprm, len)) | |
1da177e4 | 531 | goto out; |
1da177e4 | 532 | |
b6a2fea3 | 533 | /* We're going to work our way backwords. */ |
1da177e4 | 534 | pos = bprm->p; |
b6a2fea3 OW |
535 | str += len; |
536 | bprm->p -= len; | |
1da177e4 LT |
537 | |
538 | while (len > 0) { | |
1da177e4 | 539 | int offset, bytes_to_copy; |
1da177e4 | 540 | |
9aea5a65 RM |
541 | if (fatal_signal_pending(current)) { |
542 | ret = -ERESTARTNOHAND; | |
543 | goto out; | |
544 | } | |
7993bc1f RM |
545 | cond_resched(); |
546 | ||
1da177e4 | 547 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
548 | if (offset == 0) |
549 | offset = PAGE_SIZE; | |
550 | ||
551 | bytes_to_copy = offset; | |
552 | if (bytes_to_copy > len) | |
553 | bytes_to_copy = len; | |
554 | ||
555 | offset -= bytes_to_copy; | |
556 | pos -= bytes_to_copy; | |
557 | str -= bytes_to_copy; | |
558 | len -= bytes_to_copy; | |
559 | ||
560 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
561 | struct page *page; | |
562 | ||
563 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 564 | if (!page) { |
b6a2fea3 | 565 | ret = -E2BIG; |
1da177e4 LT |
566 | goto out; |
567 | } | |
1da177e4 | 568 | |
b6a2fea3 OW |
569 | if (kmapped_page) { |
570 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 571 | kunmap(kmapped_page); |
b6a2fea3 OW |
572 | put_arg_page(kmapped_page); |
573 | } | |
1da177e4 LT |
574 | kmapped_page = page; |
575 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
576 | kpos = pos & PAGE_MASK; |
577 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 578 | } |
b6a2fea3 | 579 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
580 | ret = -EFAULT; |
581 | goto out; | |
582 | } | |
1da177e4 LT |
583 | } |
584 | } | |
585 | ret = 0; | |
586 | out: | |
b6a2fea3 OW |
587 | if (kmapped_page) { |
588 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 589 | kunmap(kmapped_page); |
b6a2fea3 OW |
590 | put_arg_page(kmapped_page); |
591 | } | |
1da177e4 LT |
592 | return ret; |
593 | } | |
594 | ||
595 | /* | |
596 | * Like copy_strings, but get argv and its values from kernel memory. | |
597 | */ | |
ba2d0162 | 598 | int copy_strings_kernel(int argc, const char *const *__argv, |
d7627467 | 599 | struct linux_binprm *bprm) |
1da177e4 LT |
600 | { |
601 | int r; | |
602 | mm_segment_t oldfs = get_fs(); | |
ba2d0162 | 603 | struct user_arg_ptr argv = { |
0e028465 | 604 | .ptr.native = (const char __user *const __user *)__argv, |
ba2d0162 ON |
605 | }; |
606 | ||
1da177e4 | 607 | set_fs(KERNEL_DS); |
ba2d0162 | 608 | r = copy_strings(argc, argv, bprm); |
1da177e4 | 609 | set_fs(oldfs); |
ba2d0162 | 610 | |
1da177e4 LT |
611 | return r; |
612 | } | |
1da177e4 LT |
613 | EXPORT_SYMBOL(copy_strings_kernel); |
614 | ||
615 | #ifdef CONFIG_MMU | |
b6a2fea3 | 616 | |
1da177e4 | 617 | /* |
b6a2fea3 OW |
618 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
619 | * the binfmt code determines where the new stack should reside, we shift it to | |
620 | * its final location. The process proceeds as follows: | |
1da177e4 | 621 | * |
b6a2fea3 OW |
622 | * 1) Use shift to calculate the new vma endpoints. |
623 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
624 | * arguments passed to subsequent functions are consistent. | |
625 | * 3) Move vma's page tables to the new range. | |
626 | * 4) Free up any cleared pgd range. | |
627 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 628 | */ |
b6a2fea3 | 629 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
630 | { |
631 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
632 | unsigned long old_start = vma->vm_start; |
633 | unsigned long old_end = vma->vm_end; | |
634 | unsigned long length = old_end - old_start; | |
635 | unsigned long new_start = old_start - shift; | |
636 | unsigned long new_end = old_end - shift; | |
d16dfc55 | 637 | struct mmu_gather tlb; |
1da177e4 | 638 | |
b6a2fea3 | 639 | BUG_ON(new_start > new_end); |
1da177e4 | 640 | |
b6a2fea3 OW |
641 | /* |
642 | * ensure there are no vmas between where we want to go | |
643 | * and where we are | |
644 | */ | |
645 | if (vma != find_vma(mm, new_start)) | |
646 | return -EFAULT; | |
647 | ||
648 | /* | |
649 | * cover the whole range: [new_start, old_end) | |
650 | */ | |
5beb4930 RR |
651 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
652 | return -ENOMEM; | |
b6a2fea3 OW |
653 | |
654 | /* | |
655 | * move the page tables downwards, on failure we rely on | |
656 | * process cleanup to remove whatever mess we made. | |
657 | */ | |
658 | if (length != move_page_tables(vma, old_start, | |
38a76013 | 659 | vma, new_start, length, false)) |
b6a2fea3 OW |
660 | return -ENOMEM; |
661 | ||
662 | lru_add_drain(); | |
2b047252 | 663 | tlb_gather_mmu(&tlb, mm, old_start, old_end); |
b6a2fea3 OW |
664 | if (new_end > old_start) { |
665 | /* | |
666 | * when the old and new regions overlap clear from new_end. | |
667 | */ | |
d16dfc55 | 668 | free_pgd_range(&tlb, new_end, old_end, new_end, |
6ee8630e | 669 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
b6a2fea3 OW |
670 | } else { |
671 | /* | |
672 | * otherwise, clean from old_start; this is done to not touch | |
673 | * the address space in [new_end, old_start) some architectures | |
674 | * have constraints on va-space that make this illegal (IA64) - | |
675 | * for the others its just a little faster. | |
676 | */ | |
d16dfc55 | 677 | free_pgd_range(&tlb, old_start, old_end, new_end, |
6ee8630e | 678 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
1da177e4 | 679 | } |
2b047252 | 680 | tlb_finish_mmu(&tlb, old_start, old_end); |
b6a2fea3 OW |
681 | |
682 | /* | |
5beb4930 | 683 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
684 | */ |
685 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
686 | ||
687 | return 0; | |
1da177e4 LT |
688 | } |
689 | ||
b6a2fea3 OW |
690 | /* |
691 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
692 | * the stack is optionally relocated, and some extra space is added. | |
693 | */ | |
1da177e4 LT |
694 | int setup_arg_pages(struct linux_binprm *bprm, |
695 | unsigned long stack_top, | |
696 | int executable_stack) | |
697 | { | |
b6a2fea3 OW |
698 | unsigned long ret; |
699 | unsigned long stack_shift; | |
1da177e4 | 700 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
701 | struct vm_area_struct *vma = bprm->vma; |
702 | struct vm_area_struct *prev = NULL; | |
703 | unsigned long vm_flags; | |
704 | unsigned long stack_base; | |
803bf5ec MN |
705 | unsigned long stack_size; |
706 | unsigned long stack_expand; | |
707 | unsigned long rlim_stack; | |
1da177e4 LT |
708 | |
709 | #ifdef CONFIG_STACK_GROWSUP | |
d71f290b | 710 | /* Limit stack size */ |
d554ed89 | 711 | stack_base = rlimit_max(RLIMIT_STACK); |
d71f290b JH |
712 | if (stack_base > STACK_SIZE_MAX) |
713 | stack_base = STACK_SIZE_MAX; | |
1da177e4 | 714 | |
d045c77c HD |
715 | /* Add space for stack randomization. */ |
716 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
717 | ||
b6a2fea3 OW |
718 | /* Make sure we didn't let the argument array grow too large. */ |
719 | if (vma->vm_end - vma->vm_start > stack_base) | |
720 | return -ENOMEM; | |
1da177e4 | 721 | |
b6a2fea3 | 722 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 723 | |
b6a2fea3 OW |
724 | stack_shift = vma->vm_start - stack_base; |
725 | mm->arg_start = bprm->p - stack_shift; | |
726 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 727 | #else |
b6a2fea3 OW |
728 | stack_top = arch_align_stack(stack_top); |
729 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
730 | |
731 | if (unlikely(stack_top < mmap_min_addr) || | |
732 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
733 | return -ENOMEM; | |
734 | ||
b6a2fea3 OW |
735 | stack_shift = vma->vm_end - stack_top; |
736 | ||
737 | bprm->p -= stack_shift; | |
1da177e4 | 738 | mm->arg_start = bprm->p; |
1da177e4 LT |
739 | #endif |
740 | ||
1da177e4 | 741 | if (bprm->loader) |
b6a2fea3 OW |
742 | bprm->loader -= stack_shift; |
743 | bprm->exec -= stack_shift; | |
1da177e4 | 744 | |
f268dfe9 MH |
745 | if (down_write_killable(&mm->mmap_sem)) |
746 | return -EINTR; | |
747 | ||
96a8e13e | 748 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
749 | |
750 | /* | |
751 | * Adjust stack execute permissions; explicitly enable for | |
752 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
753 | * (arch default) otherwise. | |
754 | */ | |
755 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
756 | vm_flags |= VM_EXEC; | |
757 | else if (executable_stack == EXSTACK_DISABLE_X) | |
758 | vm_flags &= ~VM_EXEC; | |
759 | vm_flags |= mm->def_flags; | |
a8bef8ff | 760 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
761 | |
762 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
763 | vm_flags); | |
764 | if (ret) | |
765 | goto out_unlock; | |
766 | BUG_ON(prev != vma); | |
767 | ||
768 | /* Move stack pages down in memory. */ | |
769 | if (stack_shift) { | |
770 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
771 | if (ret) |
772 | goto out_unlock; | |
1da177e4 LT |
773 | } |
774 | ||
a8bef8ff MG |
775 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
776 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
777 | ||
5ef097dd | 778 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
779 | stack_size = vma->vm_end - vma->vm_start; |
780 | /* | |
781 | * Align this down to a page boundary as expand_stack | |
782 | * will align it up. | |
783 | */ | |
784 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
b6a2fea3 | 785 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
786 | if (stack_size + stack_expand > rlim_stack) |
787 | stack_base = vma->vm_start + rlim_stack; | |
788 | else | |
789 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 790 | #else |
803bf5ec MN |
791 | if (stack_size + stack_expand > rlim_stack) |
792 | stack_base = vma->vm_end - rlim_stack; | |
793 | else | |
794 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 795 | #endif |
3af9e859 | 796 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
797 | ret = expand_stack(vma, stack_base); |
798 | if (ret) | |
799 | ret = -EFAULT; | |
800 | ||
801 | out_unlock: | |
1da177e4 | 802 | up_write(&mm->mmap_sem); |
fc63cf23 | 803 | return ret; |
1da177e4 | 804 | } |
1da177e4 LT |
805 | EXPORT_SYMBOL(setup_arg_pages); |
806 | ||
7e7ec6a9 NP |
807 | #else |
808 | ||
809 | /* | |
810 | * Transfer the program arguments and environment from the holding pages | |
811 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
812 | */ | |
813 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
814 | unsigned long *sp_location) | |
815 | { | |
816 | unsigned long index, stop, sp; | |
817 | int ret = 0; | |
818 | ||
819 | stop = bprm->p >> PAGE_SHIFT; | |
820 | sp = *sp_location; | |
821 | ||
822 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
823 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
824 | char *src = kmap(bprm->page[index]) + offset; | |
825 | sp -= PAGE_SIZE - offset; | |
826 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
827 | ret = -EFAULT; | |
828 | kunmap(bprm->page[index]); | |
829 | if (ret) | |
830 | goto out; | |
831 | } | |
832 | ||
833 | *sp_location = sp; | |
834 | ||
835 | out: | |
836 | return ret; | |
837 | } | |
838 | EXPORT_SYMBOL(transfer_args_to_stack); | |
839 | ||
1da177e4 LT |
840 | #endif /* CONFIG_MMU */ |
841 | ||
51f39a1f | 842 | static struct file *do_open_execat(int fd, struct filename *name, int flags) |
1da177e4 | 843 | { |
1da177e4 | 844 | struct file *file; |
e56b6a5d | 845 | int err; |
51f39a1f | 846 | struct open_flags open_exec_flags = { |
47c805dc | 847 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
62fb4a15 | 848 | .acc_mode = MAY_EXEC, |
f9652e10 AV |
849 | .intent = LOOKUP_OPEN, |
850 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 851 | }; |
1da177e4 | 852 | |
51f39a1f DD |
853 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
854 | return ERR_PTR(-EINVAL); | |
855 | if (flags & AT_SYMLINK_NOFOLLOW) | |
856 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
857 | if (flags & AT_EMPTY_PATH) | |
858 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
859 | ||
860 | file = do_filp_open(fd, name, &open_exec_flags); | |
6e8341a1 | 861 | if (IS_ERR(file)) |
e56b6a5d CH |
862 | goto out; |
863 | ||
864 | err = -EACCES; | |
496ad9aa | 865 | if (!S_ISREG(file_inode(file)->i_mode)) |
6e8341a1 | 866 | goto exit; |
e56b6a5d | 867 | |
90f8572b | 868 | if (path_noexec(&file->f_path)) |
6e8341a1 | 869 | goto exit; |
e56b6a5d CH |
870 | |
871 | err = deny_write_access(file); | |
6e8341a1 AV |
872 | if (err) |
873 | goto exit; | |
1da177e4 | 874 | |
51f39a1f DD |
875 | if (name->name[0] != '\0') |
876 | fsnotify_open(file); | |
877 | ||
308a1eef SJR |
878 | trace_open_exec(name->name); |
879 | ||
6e8341a1 | 880 | out: |
e56b6a5d CH |
881 | return file; |
882 | ||
6e8341a1 AV |
883 | exit: |
884 | fput(file); | |
e56b6a5d CH |
885 | return ERR_PTR(err); |
886 | } | |
c4ad8f98 LT |
887 | |
888 | struct file *open_exec(const char *name) | |
889 | { | |
51689104 PM |
890 | struct filename *filename = getname_kernel(name); |
891 | struct file *f = ERR_CAST(filename); | |
892 | ||
893 | if (!IS_ERR(filename)) { | |
894 | f = do_open_execat(AT_FDCWD, filename, 0); | |
895 | putname(filename); | |
896 | } | |
897 | return f; | |
c4ad8f98 | 898 | } |
1da177e4 LT |
899 | EXPORT_SYMBOL(open_exec); |
900 | ||
6777d773 MZ |
901 | int kernel_read(struct file *file, loff_t offset, |
902 | char *addr, unsigned long count) | |
1da177e4 LT |
903 | { |
904 | mm_segment_t old_fs; | |
905 | loff_t pos = offset; | |
906 | int result; | |
907 | ||
908 | old_fs = get_fs(); | |
909 | set_fs(get_ds()); | |
910 | /* The cast to a user pointer is valid due to the set_fs() */ | |
911 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
912 | set_fs(old_fs); | |
913 | return result; | |
914 | } | |
915 | ||
916 | EXPORT_SYMBOL(kernel_read); | |
917 | ||
b44a7dfc | 918 | int kernel_read_file(struct file *file, void **buf, loff_t *size, |
bc8ca5b9 | 919 | loff_t max_size, enum kernel_read_file_id id) |
b44a7dfc MZ |
920 | { |
921 | loff_t i_size, pos; | |
922 | ssize_t bytes = 0; | |
923 | int ret; | |
924 | ||
925 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
926 | return -EINVAL; | |
927 | ||
39eeb4fb MZ |
928 | ret = security_kernel_read_file(file, id); |
929 | if (ret) | |
930 | return ret; | |
931 | ||
39d637af DK |
932 | ret = deny_write_access(file); |
933 | if (ret) | |
934 | return ret; | |
935 | ||
b44a7dfc | 936 | i_size = i_size_read(file_inode(file)); |
39d637af DK |
937 | if (max_size > 0 && i_size > max_size) { |
938 | ret = -EFBIG; | |
939 | goto out; | |
940 | } | |
941 | if (i_size <= 0) { | |
942 | ret = -EINVAL; | |
943 | goto out; | |
944 | } | |
b44a7dfc | 945 | |
a098ecd2 SB |
946 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) |
947 | *buf = vmalloc(i_size); | |
39d637af DK |
948 | if (!*buf) { |
949 | ret = -ENOMEM; | |
950 | goto out; | |
951 | } | |
b44a7dfc MZ |
952 | |
953 | pos = 0; | |
954 | while (pos < i_size) { | |
955 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
956 | i_size - pos); | |
957 | if (bytes < 0) { | |
958 | ret = bytes; | |
959 | goto out; | |
960 | } | |
961 | ||
962 | if (bytes == 0) | |
963 | break; | |
964 | pos += bytes; | |
965 | } | |
966 | ||
967 | if (pos != i_size) { | |
968 | ret = -EIO; | |
39d637af | 969 | goto out_free; |
b44a7dfc MZ |
970 | } |
971 | ||
bc8ca5b9 | 972 | ret = security_kernel_post_read_file(file, *buf, i_size, id); |
b44a7dfc MZ |
973 | if (!ret) |
974 | *size = pos; | |
975 | ||
39d637af | 976 | out_free: |
b44a7dfc | 977 | if (ret < 0) { |
a098ecd2 SB |
978 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { |
979 | vfree(*buf); | |
980 | *buf = NULL; | |
981 | } | |
b44a7dfc | 982 | } |
39d637af DK |
983 | |
984 | out: | |
985 | allow_write_access(file); | |
b44a7dfc MZ |
986 | return ret; |
987 | } | |
988 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
989 | ||
09596b94 MZ |
990 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, |
991 | loff_t max_size, enum kernel_read_file_id id) | |
992 | { | |
993 | struct file *file; | |
994 | int ret; | |
995 | ||
996 | if (!path || !*path) | |
997 | return -EINVAL; | |
998 | ||
999 | file = filp_open(path, O_RDONLY, 0); | |
1000 | if (IS_ERR(file)) | |
1001 | return PTR_ERR(file); | |
1002 | ||
1003 | ret = kernel_read_file(file, buf, size, max_size, id); | |
1004 | fput(file); | |
1005 | return ret; | |
1006 | } | |
1007 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
1008 | ||
b844f0ec MZ |
1009 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, |
1010 | enum kernel_read_file_id id) | |
1011 | { | |
1012 | struct fd f = fdget(fd); | |
1013 | int ret = -EBADF; | |
1014 | ||
1015 | if (!f.file) | |
1016 | goto out; | |
1017 | ||
1018 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
1019 | out: | |
1020 | fdput(f); | |
1021 | return ret; | |
1022 | } | |
1023 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
1024 | ||
3dc20cb2 AV |
1025 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) |
1026 | { | |
ec695579 | 1027 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); |
3dc20cb2 AV |
1028 | if (res > 0) |
1029 | flush_icache_range(addr, addr + len); | |
1030 | return res; | |
1031 | } | |
1032 | EXPORT_SYMBOL(read_code); | |
1033 | ||
1da177e4 LT |
1034 | static int exec_mmap(struct mm_struct *mm) |
1035 | { | |
1036 | struct task_struct *tsk; | |
615d6e87 | 1037 | struct mm_struct *old_mm, *active_mm; |
1da177e4 LT |
1038 | |
1039 | /* Notify parent that we're no longer interested in the old VM */ | |
1040 | tsk = current; | |
1041 | old_mm = current->mm; | |
1042 | mm_release(tsk, old_mm); | |
1043 | ||
1044 | if (old_mm) { | |
4fe7efdb | 1045 | sync_mm_rss(old_mm); |
1da177e4 LT |
1046 | /* |
1047 | * Make sure that if there is a core dump in progress | |
1048 | * for the old mm, we get out and die instead of going | |
1049 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 1050 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
1051 | */ |
1052 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 1053 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
1054 | up_read(&old_mm->mmap_sem); |
1055 | return -EINTR; | |
1056 | } | |
1057 | } | |
1058 | task_lock(tsk); | |
1059 | active_mm = tsk->active_mm; | |
1060 | tsk->mm = mm; | |
1061 | tsk->active_mm = mm; | |
1062 | activate_mm(active_mm, mm); | |
615d6e87 DB |
1063 | tsk->mm->vmacache_seqnum = 0; |
1064 | vmacache_flush(tsk); | |
1da177e4 | 1065 | task_unlock(tsk); |
1da177e4 LT |
1066 | if (old_mm) { |
1067 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 1068 | BUG_ON(active_mm != old_mm); |
701085b2 | 1069 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
31a78f23 | 1070 | mm_update_next_owner(old_mm); |
1da177e4 LT |
1071 | mmput(old_mm); |
1072 | return 0; | |
1073 | } | |
1074 | mmdrop(active_mm); | |
1075 | return 0; | |
1076 | } | |
1077 | ||
1078 | /* | |
1079 | * This function makes sure the current process has its own signal table, | |
1080 | * so that flush_signal_handlers can later reset the handlers without | |
1081 | * disturbing other processes. (Other processes might share the signal | |
1082 | * table via the CLONE_SIGHAND option to clone().) | |
1083 | */ | |
858119e1 | 1084 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
1085 | { |
1086 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 1087 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 1088 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 1089 | |
aafe6c2a | 1090 | if (thread_group_empty(tsk)) |
1da177e4 LT |
1091 | goto no_thread_group; |
1092 | ||
1093 | /* | |
1094 | * Kill all other threads in the thread group. | |
1da177e4 | 1095 | */ |
1da177e4 | 1096 | spin_lock_irq(lock); |
ed5d2cac | 1097 | if (signal_group_exit(sig)) { |
1da177e4 LT |
1098 | /* |
1099 | * Another group action in progress, just | |
1100 | * return so that the signal is processed. | |
1101 | */ | |
1102 | spin_unlock_irq(lock); | |
1da177e4 LT |
1103 | return -EAGAIN; |
1104 | } | |
d344193a | 1105 | |
ed5d2cac | 1106 | sig->group_exit_task = tsk; |
d344193a ON |
1107 | sig->notify_count = zap_other_threads(tsk); |
1108 | if (!thread_group_leader(tsk)) | |
1109 | sig->notify_count--; | |
1da177e4 | 1110 | |
d344193a | 1111 | while (sig->notify_count) { |
d5bbd43d | 1112 | __set_current_state(TASK_KILLABLE); |
1da177e4 LT |
1113 | spin_unlock_irq(lock); |
1114 | schedule(); | |
d5bbd43d ON |
1115 | if (unlikely(__fatal_signal_pending(tsk))) |
1116 | goto killed; | |
1da177e4 LT |
1117 | spin_lock_irq(lock); |
1118 | } | |
1da177e4 LT |
1119 | spin_unlock_irq(lock); |
1120 | ||
1121 | /* | |
1122 | * At this point all other threads have exited, all we have to | |
1123 | * do is to wait for the thread group leader to become inactive, | |
1124 | * and to assume its PID: | |
1125 | */ | |
aafe6c2a | 1126 | if (!thread_group_leader(tsk)) { |
8187926b | 1127 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 1128 | |
6db840fa | 1129 | for (;;) { |
780de9dd | 1130 | cgroup_threadgroup_change_begin(tsk); |
6db840fa | 1131 | write_lock_irq(&tasklist_lock); |
dfcce791 KT |
1132 | /* |
1133 | * Do this under tasklist_lock to ensure that | |
1134 | * exit_notify() can't miss ->group_exit_task | |
1135 | */ | |
1136 | sig->notify_count = -1; | |
6db840fa ON |
1137 | if (likely(leader->exit_state)) |
1138 | break; | |
d5bbd43d | 1139 | __set_current_state(TASK_KILLABLE); |
6db840fa | 1140 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1141 | cgroup_threadgroup_change_end(tsk); |
6db840fa | 1142 | schedule(); |
d5bbd43d ON |
1143 | if (unlikely(__fatal_signal_pending(tsk))) |
1144 | goto killed; | |
6db840fa | 1145 | } |
1da177e4 | 1146 | |
f5e90281 RM |
1147 | /* |
1148 | * The only record we have of the real-time age of a | |
1149 | * process, regardless of execs it's done, is start_time. | |
1150 | * All the past CPU time is accumulated in signal_struct | |
1151 | * from sister threads now dead. But in this non-leader | |
1152 | * exec, nothing survives from the original leader thread, | |
1153 | * whose birth marks the true age of this process now. | |
1154 | * When we take on its identity by switching to its PID, we | |
1155 | * also take its birthdate (always earlier than our own). | |
1156 | */ | |
aafe6c2a | 1157 | tsk->start_time = leader->start_time; |
266b7a02 | 1158 | tsk->real_start_time = leader->real_start_time; |
f5e90281 | 1159 | |
bac0abd6 PE |
1160 | BUG_ON(!same_thread_group(leader, tsk)); |
1161 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
1162 | /* |
1163 | * An exec() starts a new thread group with the | |
1164 | * TGID of the previous thread group. Rehash the | |
1165 | * two threads with a switched PID, and release | |
1166 | * the former thread group leader: | |
1167 | */ | |
d73d6529 EB |
1168 | |
1169 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
1170 | * The old leader becomes a thread of the this thread group. |
1171 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
1172 | * is called. Odd but simple and correct. |
1173 | */ | |
aafe6c2a | 1174 | tsk->pid = leader->pid; |
3f418548 | 1175 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
1176 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
1177 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 1178 | |
aafe6c2a | 1179 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 1180 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 1181 | |
aafe6c2a EB |
1182 | tsk->group_leader = tsk; |
1183 | leader->group_leader = tsk; | |
de12a787 | 1184 | |
aafe6c2a | 1185 | tsk->exit_signal = SIGCHLD; |
087806b1 | 1186 | leader->exit_signal = -1; |
962b564c ON |
1187 | |
1188 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1189 | leader->exit_state = EXIT_DEAD; | |
eac1b5e5 ON |
1190 | |
1191 | /* | |
1192 | * We are going to release_task()->ptrace_unlink() silently, | |
1193 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1194 | * the tracer wont't block again waiting for this thread. | |
1195 | */ | |
1196 | if (unlikely(leader->ptrace)) | |
1197 | __wake_up_parent(leader, leader->parent); | |
1da177e4 | 1198 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1199 | cgroup_threadgroup_change_end(tsk); |
8187926b ON |
1200 | |
1201 | release_task(leader); | |
ed5d2cac | 1202 | } |
1da177e4 | 1203 | |
6db840fa ON |
1204 | sig->group_exit_task = NULL; |
1205 | sig->notify_count = 0; | |
1da177e4 LT |
1206 | |
1207 | no_thread_group: | |
e6368253 ON |
1208 | /* we have changed execution domain */ |
1209 | tsk->exit_signal = SIGCHLD; | |
1210 | ||
baa73d9e | 1211 | #ifdef CONFIG_POSIX_TIMERS |
1da177e4 | 1212 | exit_itimers(sig); |
cbaffba1 | 1213 | flush_itimer_signals(); |
baa73d9e | 1214 | #endif |
329f7dba | 1215 | |
b2c903b8 ON |
1216 | if (atomic_read(&oldsighand->count) != 1) { |
1217 | struct sighand_struct *newsighand; | |
1da177e4 | 1218 | /* |
b2c903b8 ON |
1219 | * This ->sighand is shared with the CLONE_SIGHAND |
1220 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 1221 | */ |
b2c903b8 ON |
1222 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
1223 | if (!newsighand) | |
1224 | return -ENOMEM; | |
1225 | ||
1da177e4 LT |
1226 | atomic_set(&newsighand->count, 1); |
1227 | memcpy(newsighand->action, oldsighand->action, | |
1228 | sizeof(newsighand->action)); | |
1229 | ||
1230 | write_lock_irq(&tasklist_lock); | |
1231 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 1232 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
1233 | spin_unlock(&oldsighand->siglock); |
1234 | write_unlock_irq(&tasklist_lock); | |
1235 | ||
fba2afaa | 1236 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
1237 | } |
1238 | ||
aafe6c2a | 1239 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 | 1240 | return 0; |
d5bbd43d ON |
1241 | |
1242 | killed: | |
1243 | /* protects against exit_notify() and __exit_signal() */ | |
1244 | read_lock(&tasklist_lock); | |
1245 | sig->group_exit_task = NULL; | |
1246 | sig->notify_count = 0; | |
1247 | read_unlock(&tasklist_lock); | |
1248 | return -EAGAIN; | |
1da177e4 | 1249 | } |
0840a90d | 1250 | |
59714d65 | 1251 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
1252 | { |
1253 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1254 | task_lock(tsk); | |
1255 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1256 | task_unlock(tsk); | |
59714d65 | 1257 | return buf; |
1da177e4 | 1258 | } |
7d74f492 | 1259 | EXPORT_SYMBOL_GPL(get_task_comm); |
1da177e4 | 1260 | |
6a6d27de AV |
1261 | /* |
1262 | * These functions flushes out all traces of the currently running executable | |
1263 | * so that a new one can be started | |
1264 | */ | |
1265 | ||
82b89778 | 1266 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) |
1da177e4 LT |
1267 | { |
1268 | task_lock(tsk); | |
43d2b113 | 1269 | trace_task_rename(tsk, buf); |
1da177e4 LT |
1270 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1271 | task_unlock(tsk); | |
82b89778 | 1272 | perf_event_comm(tsk, exec); |
1da177e4 LT |
1273 | } |
1274 | ||
1275 | int flush_old_exec(struct linux_binprm * bprm) | |
1276 | { | |
221af7f8 | 1277 | int retval; |
1da177e4 LT |
1278 | |
1279 | /* | |
1280 | * Make sure we have a private signal table and that | |
1281 | * we are unassociated from the previous thread group. | |
1282 | */ | |
1283 | retval = de_thread(current); | |
1284 | if (retval) | |
1285 | goto out; | |
1286 | ||
6e399cd1 DB |
1287 | /* |
1288 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1289 | * not visibile until then. This also enables the update | |
1290 | * to be lockless. | |
1291 | */ | |
925d1c40 | 1292 | set_mm_exe_file(bprm->mm, bprm->file); |
6e399cd1 | 1293 | |
1da177e4 LT |
1294 | /* |
1295 | * Release all of the old mmap stuff | |
1296 | */ | |
3c77f845 | 1297 | acct_arg_size(bprm, 0); |
1da177e4 LT |
1298 | retval = exec_mmap(bprm->mm); |
1299 | if (retval) | |
fd8328be | 1300 | goto out; |
1da177e4 LT |
1301 | |
1302 | bprm->mm = NULL; /* We're using it now */ | |
7ab02af4 | 1303 | |
dac853ae | 1304 | set_fs(USER_DS); |
b88fae64 ZY |
1305 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | |
1306 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
7ab02af4 LT |
1307 | flush_thread(); |
1308 | current->personality &= ~bprm->per_clear; | |
1309 | ||
613cc2b6 AS |
1310 | /* |
1311 | * We have to apply CLOEXEC before we change whether the process is | |
1312 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1313 | * trying to access the should-be-closed file descriptors of a process | |
1314 | * undergoing exec(2). | |
1315 | */ | |
1316 | do_close_on_exec(current->files); | |
221af7f8 LT |
1317 | return 0; |
1318 | ||
1319 | out: | |
1320 | return retval; | |
1321 | } | |
1322 | EXPORT_SYMBOL(flush_old_exec); | |
1323 | ||
1b5d783c AV |
1324 | void would_dump(struct linux_binprm *bprm, struct file *file) |
1325 | { | |
f84df2a6 EB |
1326 | struct inode *inode = file_inode(file); |
1327 | if (inode_permission(inode, MAY_READ) < 0) { | |
1328 | struct user_namespace *old, *user_ns; | |
1b5d783c | 1329 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
f84df2a6 EB |
1330 | |
1331 | /* Ensure mm->user_ns contains the executable */ | |
1332 | user_ns = old = bprm->mm->user_ns; | |
1333 | while ((user_ns != &init_user_ns) && | |
1334 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1335 | user_ns = user_ns->parent; | |
1336 | ||
1337 | if (old != user_ns) { | |
1338 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1339 | put_user_ns(old); | |
1340 | } | |
1341 | } | |
1b5d783c AV |
1342 | } |
1343 | EXPORT_SYMBOL(would_dump); | |
1344 | ||
221af7f8 LT |
1345 | void setup_new_exec(struct linux_binprm * bprm) |
1346 | { | |
221af7f8 | 1347 | arch_pick_mmap_layout(current->mm); |
1da177e4 LT |
1348 | |
1349 | /* This is the point of no return */ | |
1da177e4 LT |
1350 | current->sas_ss_sp = current->sas_ss_size = 0; |
1351 | ||
8e96e3b7 | 1352 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) |
e579d2c2 | 1353 | set_dumpable(current->mm, SUID_DUMP_USER); |
d6e71144 | 1354 | else |
6c5d5238 | 1355 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1356 | |
e9ea1e7f | 1357 | arch_setup_new_exec(); |
e041e328 | 1358 | perf_event_exec(); |
82b89778 | 1359 | __set_task_comm(current, kbasename(bprm->filename), true); |
1da177e4 | 1360 | |
0551fbd2 BH |
1361 | /* Set the new mm task size. We have to do that late because it may |
1362 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1363 | * some architectures like powerpc | |
1364 | */ | |
1365 | current->mm->task_size = TASK_SIZE; | |
1366 | ||
a6f76f23 | 1367 | /* install the new credentials */ |
8e96e3b7 EB |
1368 | if (!uid_eq(bprm->cred->uid, current_euid()) || |
1369 | !gid_eq(bprm->cred->gid, current_egid())) { | |
d2d56c5f | 1370 | current->pdeath_signal = 0; |
1b5d783c | 1371 | } else { |
1b5d783c AV |
1372 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) |
1373 | set_dumpable(current->mm, suid_dumpable); | |
1da177e4 LT |
1374 | } |
1375 | ||
1376 | /* An exec changes our domain. We are no longer part of the thread | |
1377 | group */ | |
1da177e4 | 1378 | current->self_exec_id++; |
1da177e4 | 1379 | flush_signal_handlers(current, 0); |
1da177e4 | 1380 | } |
221af7f8 | 1381 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1382 | |
a2a8474c ON |
1383 | /* |
1384 | * Prepare credentials and lock ->cred_guard_mutex. | |
1385 | * install_exec_creds() commits the new creds and drops the lock. | |
1386 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1387 | * and unlock. | |
1388 | */ | |
1389 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1390 | { | |
9b1bf12d | 1391 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
a2a8474c ON |
1392 | return -ERESTARTNOINTR; |
1393 | ||
1394 | bprm->cred = prepare_exec_creds(); | |
1395 | if (likely(bprm->cred)) | |
1396 | return 0; | |
1397 | ||
9b1bf12d | 1398 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1399 | return -ENOMEM; |
1400 | } | |
1401 | ||
c4ad8f98 | 1402 | static void free_bprm(struct linux_binprm *bprm) |
a2a8474c ON |
1403 | { |
1404 | free_arg_pages(bprm); | |
1405 | if (bprm->cred) { | |
9b1bf12d | 1406 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1407 | abort_creds(bprm->cred); |
1408 | } | |
63e46b95 ON |
1409 | if (bprm->file) { |
1410 | allow_write_access(bprm->file); | |
1411 | fput(bprm->file); | |
1412 | } | |
b66c5984 KC |
1413 | /* If a binfmt changed the interp, free it. */ |
1414 | if (bprm->interp != bprm->filename) | |
1415 | kfree(bprm->interp); | |
a2a8474c ON |
1416 | kfree(bprm); |
1417 | } | |
1418 | ||
b66c5984 KC |
1419 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) |
1420 | { | |
1421 | /* If a binfmt changed the interp, free it first. */ | |
1422 | if (bprm->interp != bprm->filename) | |
1423 | kfree(bprm->interp); | |
1424 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1425 | if (!bprm->interp) | |
1426 | return -ENOMEM; | |
1427 | return 0; | |
1428 | } | |
1429 | EXPORT_SYMBOL(bprm_change_interp); | |
1430 | ||
a6f76f23 DH |
1431 | /* |
1432 | * install the new credentials for this executable | |
1433 | */ | |
1434 | void install_exec_creds(struct linux_binprm *bprm) | |
1435 | { | |
1436 | security_bprm_committing_creds(bprm); | |
1437 | ||
1438 | commit_creds(bprm->cred); | |
1439 | bprm->cred = NULL; | |
2976b10f SE |
1440 | |
1441 | /* | |
1442 | * Disable monitoring for regular users | |
1443 | * when executing setuid binaries. Must | |
1444 | * wait until new credentials are committed | |
1445 | * by commit_creds() above | |
1446 | */ | |
1447 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1448 | perf_event_exit_task(current); | |
a2a8474c ON |
1449 | /* |
1450 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1451 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1452 | * credentials; any time after this it may be unlocked. |
1453 | */ | |
a6f76f23 | 1454 | security_bprm_committed_creds(bprm); |
9b1bf12d | 1455 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a6f76f23 DH |
1456 | } |
1457 | EXPORT_SYMBOL(install_exec_creds); | |
1458 | ||
1459 | /* | |
1460 | * determine how safe it is to execute the proposed program | |
9b1bf12d | 1461 | * - the caller must hold ->cred_guard_mutex to protect against |
c2e1f2e3 | 1462 | * PTRACE_ATTACH or seccomp thread-sync |
a6f76f23 | 1463 | */ |
9e00cdb0 | 1464 | static void check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1465 | { |
0bf2f3ae | 1466 | struct task_struct *p = current, *t; |
f1191b50 | 1467 | unsigned n_fs; |
0f589e86 | 1468 | bool fs_recheck; |
4d7b698b | 1469 | int count = 0; |
a6f76f23 | 1470 | |
9227dd2a EB |
1471 | if (p->ptrace) |
1472 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
a6f76f23 | 1473 | |
259e5e6c AL |
1474 | /* |
1475 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1476 | * mess up. | |
1477 | */ | |
1d4457f9 | 1478 | if (task_no_new_privs(current)) |
259e5e6c AL |
1479 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
1480 | ||
0f589e86 CIK |
1481 | recheck: |
1482 | fs_recheck = false; | |
83f62a2e | 1483 | t = p; |
0bf2f3ae | 1484 | n_fs = 1; |
2a4419b5 | 1485 | spin_lock(&p->fs->lock); |
437f7fdb | 1486 | rcu_read_lock(); |
83f62a2e | 1487 | while_each_thread(p, t) { |
0bf2f3ae DH |
1488 | if (t->fs == p->fs) |
1489 | n_fs++; | |
0f589e86 CIK |
1490 | if (t->flags & (PF_EXITING | PF_FORKNOEXEC)) |
1491 | fs_recheck = true; | |
0bf2f3ae | 1492 | } |
437f7fdb | 1493 | rcu_read_unlock(); |
0bf2f3ae | 1494 | |
0f589e86 CIK |
1495 | if (p->fs->users > n_fs) { |
1496 | if (fs_recheck) { | |
4d7b698b CIK |
1497 | if (count++ < 20) { |
1498 | spin_unlock(&p->fs->lock); | |
1499 | msleep_interruptible(1); | |
1500 | goto recheck; | |
1501 | } | |
0f589e86 | 1502 | } |
a6f76f23 | 1503 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
0f589e86 | 1504 | } else |
9e00cdb0 | 1505 | p->fs->in_exec = 1; |
2a4419b5 | 1506 | spin_unlock(&p->fs->lock); |
a6f76f23 DH |
1507 | } |
1508 | ||
8b01fc86 JH |
1509 | static void bprm_fill_uid(struct linux_binprm *bprm) |
1510 | { | |
1511 | struct inode *inode; | |
1512 | unsigned int mode; | |
1513 | kuid_t uid; | |
1514 | kgid_t gid; | |
1515 | ||
cb6fd68f KC |
1516 | /* |
1517 | * Since this can be called multiple times (via prepare_binprm), | |
1518 | * we must clear any previous work done when setting set[ug]id | |
1519 | * bits from any earlier bprm->file uses (for example when run | |
1520 | * first for a setuid script then again for its interpreter). | |
1521 | */ | |
8b01fc86 JH |
1522 | bprm->cred->euid = current_euid(); |
1523 | bprm->cred->egid = current_egid(); | |
1524 | ||
0dc04886 | 1525 | if (path_nosuid(&bprm->file->f_path)) |
8b01fc86 JH |
1526 | return; |
1527 | ||
1528 | if (task_no_new_privs(current)) | |
1529 | return; | |
1530 | ||
fea6d2a6 | 1531 | inode = bprm->file->f_path.dentry->d_inode; |
8b01fc86 JH |
1532 | mode = READ_ONCE(inode->i_mode); |
1533 | if (!(mode & (S_ISUID|S_ISGID))) | |
1534 | return; | |
1535 | ||
1536 | /* Be careful if suid/sgid is set */ | |
5955102c | 1537 | inode_lock(inode); |
8b01fc86 JH |
1538 | |
1539 | /* reload atomically mode/uid/gid now that lock held */ | |
1540 | mode = inode->i_mode; | |
1541 | uid = inode->i_uid; | |
1542 | gid = inode->i_gid; | |
5955102c | 1543 | inode_unlock(inode); |
8b01fc86 JH |
1544 | |
1545 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1546 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1547 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1548 | return; | |
1549 | ||
1550 | if (mode & S_ISUID) { | |
1551 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1552 | bprm->cred->euid = uid; | |
1553 | } | |
1554 | ||
1555 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1556 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1557 | bprm->cred->egid = gid; | |
1558 | } | |
1559 | } | |
1560 | ||
9e00cdb0 ON |
1561 | /* |
1562 | * Fill the binprm structure from the inode. | |
1da177e4 | 1563 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
a6f76f23 DH |
1564 | * |
1565 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1566 | */ |
1567 | int prepare_binprm(struct linux_binprm *bprm) | |
1568 | { | |
1da177e4 LT |
1569 | int retval; |
1570 | ||
8b01fc86 | 1571 | bprm_fill_uid(bprm); |
1da177e4 LT |
1572 | |
1573 | /* fill in binprm security blob */ | |
a6f76f23 | 1574 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1575 | if (retval) |
1576 | return retval; | |
a6f76f23 | 1577 | bprm->cred_prepared = 1; |
1da177e4 | 1578 | |
a6f76f23 DH |
1579 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1580 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1581 | } |
1582 | ||
1583 | EXPORT_SYMBOL(prepare_binprm); | |
1584 | ||
4fc75ff4 NP |
1585 | /* |
1586 | * Arguments are '\0' separated strings found at the location bprm->p | |
1587 | * points to; chop off the first by relocating brpm->p to right after | |
1588 | * the first '\0' encountered. | |
1589 | */ | |
b6a2fea3 | 1590 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1591 | { |
b6a2fea3 OW |
1592 | int ret = 0; |
1593 | unsigned long offset; | |
1594 | char *kaddr; | |
1595 | struct page *page; | |
4fc75ff4 | 1596 | |
b6a2fea3 OW |
1597 | if (!bprm->argc) |
1598 | return 0; | |
1da177e4 | 1599 | |
b6a2fea3 OW |
1600 | do { |
1601 | offset = bprm->p & ~PAGE_MASK; | |
1602 | page = get_arg_page(bprm, bprm->p, 0); | |
1603 | if (!page) { | |
1604 | ret = -EFAULT; | |
1605 | goto out; | |
1606 | } | |
e8e3c3d6 | 1607 | kaddr = kmap_atomic(page); |
4fc75ff4 | 1608 | |
b6a2fea3 OW |
1609 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1610 | offset++, bprm->p++) | |
1611 | ; | |
4fc75ff4 | 1612 | |
e8e3c3d6 | 1613 | kunmap_atomic(kaddr); |
b6a2fea3 | 1614 | put_arg_page(page); |
b6a2fea3 | 1615 | } while (offset == PAGE_SIZE); |
4fc75ff4 | 1616 | |
b6a2fea3 OW |
1617 | bprm->p++; |
1618 | bprm->argc--; | |
1619 | ret = 0; | |
4fc75ff4 | 1620 | |
b6a2fea3 OW |
1621 | out: |
1622 | return ret; | |
1da177e4 | 1623 | } |
1da177e4 LT |
1624 | EXPORT_SYMBOL(remove_arg_zero); |
1625 | ||
cb7b6b1c | 1626 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1da177e4 LT |
1627 | /* |
1628 | * cycle the list of binary formats handler, until one recognizes the image | |
1629 | */ | |
3c456bfc | 1630 | int search_binary_handler(struct linux_binprm *bprm) |
1da177e4 | 1631 | { |
cb7b6b1c | 1632 | bool need_retry = IS_ENABLED(CONFIG_MODULES); |
1da177e4 | 1633 | struct linux_binfmt *fmt; |
cb7b6b1c | 1634 | int retval; |
1da177e4 | 1635 | |
d7402698 | 1636 | /* This allows 4 levels of binfmt rewrites before failing hard. */ |
131b2f9f | 1637 | if (bprm->recursion_depth > 5) |
d7402698 KC |
1638 | return -ELOOP; |
1639 | ||
1da177e4 LT |
1640 | retval = security_bprm_check(bprm); |
1641 | if (retval) | |
1642 | return retval; | |
1643 | ||
1da177e4 | 1644 | retval = -ENOENT; |
cb7b6b1c ON |
1645 | retry: |
1646 | read_lock(&binfmt_lock); | |
1647 | list_for_each_entry(fmt, &formats, lh) { | |
1648 | if (!try_module_get(fmt->module)) | |
1649 | continue; | |
1650 | read_unlock(&binfmt_lock); | |
1651 | bprm->recursion_depth++; | |
1652 | retval = fmt->load_binary(bprm); | |
19d860a1 AV |
1653 | read_lock(&binfmt_lock); |
1654 | put_binfmt(fmt); | |
cb7b6b1c | 1655 | bprm->recursion_depth--; |
19d860a1 AV |
1656 | if (retval < 0 && !bprm->mm) { |
1657 | /* we got to flush_old_exec() and failed after it */ | |
1658 | read_unlock(&binfmt_lock); | |
1659 | force_sigsegv(SIGSEGV, current); | |
1660 | return retval; | |
1661 | } | |
1662 | if (retval != -ENOEXEC || !bprm->file) { | |
1663 | read_unlock(&binfmt_lock); | |
cb7b6b1c | 1664 | return retval; |
1da177e4 | 1665 | } |
1da177e4 | 1666 | } |
cb7b6b1c ON |
1667 | read_unlock(&binfmt_lock); |
1668 | ||
19d860a1 | 1669 | if (need_retry) { |
cb7b6b1c ON |
1670 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && |
1671 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1672 | return retval; | |
4e0621a0 ON |
1673 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) |
1674 | return retval; | |
cb7b6b1c ON |
1675 | need_retry = false; |
1676 | goto retry; | |
1677 | } | |
1678 | ||
1da177e4 LT |
1679 | return retval; |
1680 | } | |
1da177e4 LT |
1681 | EXPORT_SYMBOL(search_binary_handler); |
1682 | ||
5d1baf3b ON |
1683 | static int exec_binprm(struct linux_binprm *bprm) |
1684 | { | |
1685 | pid_t old_pid, old_vpid; | |
1686 | int ret; | |
1687 | ||
1688 | /* Need to fetch pid before load_binary changes it */ | |
1689 | old_pid = current->pid; | |
1690 | rcu_read_lock(); | |
1691 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1692 | rcu_read_unlock(); | |
1693 | ||
1694 | ret = search_binary_handler(bprm); | |
1695 | if (ret >= 0) { | |
3eaded86 | 1696 | audit_bprm(bprm); |
5d1baf3b ON |
1697 | trace_sched_process_exec(current, old_pid, bprm); |
1698 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
9beb266f | 1699 | proc_exec_connector(current); |
5d1baf3b ON |
1700 | } |
1701 | ||
1702 | return ret; | |
1703 | } | |
1704 | ||
1da177e4 LT |
1705 | /* |
1706 | * sys_execve() executes a new program. | |
1707 | */ | |
51f39a1f DD |
1708 | static int do_execveat_common(int fd, struct filename *filename, |
1709 | struct user_arg_ptr argv, | |
1710 | struct user_arg_ptr envp, | |
1711 | int flags) | |
1da177e4 | 1712 | { |
51f39a1f | 1713 | char *pathbuf = NULL; |
1da177e4 LT |
1714 | struct linux_binprm *bprm; |
1715 | struct file *file; | |
3b125388 | 1716 | struct files_struct *displaced; |
1da177e4 | 1717 | int retval; |
72fa5997 | 1718 | |
c4ad8f98 LT |
1719 | if (IS_ERR(filename)) |
1720 | return PTR_ERR(filename); | |
1721 | ||
72fa5997 VK |
1722 | /* |
1723 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1724 | * set*uid() to execve() because too many poorly written programs | |
1725 | * don't check setuid() return code. Here we additionally recheck | |
1726 | * whether NPROC limit is still exceeded. | |
1727 | */ | |
1728 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
bd9d43f4 | 1729 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { |
72fa5997 VK |
1730 | retval = -EAGAIN; |
1731 | goto out_ret; | |
1732 | } | |
1733 | ||
1734 | /* We're below the limit (still or again), so we don't want to make | |
1735 | * further execve() calls fail. */ | |
1736 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1da177e4 | 1737 | |
3b125388 | 1738 | retval = unshare_files(&displaced); |
fd8328be AV |
1739 | if (retval) |
1740 | goto out_ret; | |
1741 | ||
1da177e4 | 1742 | retval = -ENOMEM; |
11b0b5ab | 1743 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1744 | if (!bprm) |
fd8328be | 1745 | goto out_files; |
1da177e4 | 1746 | |
a2a8474c ON |
1747 | retval = prepare_bprm_creds(bprm); |
1748 | if (retval) | |
a6f76f23 | 1749 | goto out_free; |
498052bb | 1750 | |
9e00cdb0 | 1751 | check_unsafe_exec(bprm); |
a2a8474c | 1752 | current->in_execve = 1; |
a6f76f23 | 1753 | |
51f39a1f | 1754 | file = do_open_execat(fd, filename, flags); |
1da177e4 LT |
1755 | retval = PTR_ERR(file); |
1756 | if (IS_ERR(file)) | |
498052bb | 1757 | goto out_unmark; |
1da177e4 LT |
1758 | |
1759 | sched_exec(); | |
1760 | ||
1da177e4 | 1761 | bprm->file = file; |
51f39a1f DD |
1762 | if (fd == AT_FDCWD || filename->name[0] == '/') { |
1763 | bprm->filename = filename->name; | |
1764 | } else { | |
1765 | if (filename->name[0] == '\0') | |
1766 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1767 | else | |
1768 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1769 | fd, filename->name); | |
1770 | if (!pathbuf) { | |
1771 | retval = -ENOMEM; | |
1772 | goto out_unmark; | |
1773 | } | |
1774 | /* | |
1775 | * Record that a name derived from an O_CLOEXEC fd will be | |
1776 | * inaccessible after exec. Relies on having exclusive access to | |
1777 | * current->files (due to unshare_files above). | |
1778 | */ | |
1779 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1780 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1781 | bprm->filename = pathbuf; | |
1782 | } | |
1783 | bprm->interp = bprm->filename; | |
1da177e4 | 1784 | |
b6a2fea3 OW |
1785 | retval = bprm_mm_init(bprm); |
1786 | if (retval) | |
63e46b95 | 1787 | goto out_unmark; |
1da177e4 | 1788 | |
b6a2fea3 | 1789 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1790 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1791 | goto out; |
1da177e4 | 1792 | |
b6a2fea3 | 1793 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1794 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1795 | goto out; |
1796 | ||
1797 | retval = prepare_binprm(bprm); | |
1798 | if (retval < 0) | |
1799 | goto out; | |
1800 | ||
1801 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1802 | if (retval < 0) | |
1803 | goto out; | |
1804 | ||
1805 | bprm->exec = bprm->p; | |
1806 | retval = copy_strings(bprm->envc, envp, bprm); | |
1807 | if (retval < 0) | |
1808 | goto out; | |
1809 | ||
1810 | retval = copy_strings(bprm->argc, argv, bprm); | |
1811 | if (retval < 0) | |
1812 | goto out; | |
1813 | ||
f84df2a6 EB |
1814 | would_dump(bprm, bprm->file); |
1815 | ||
5d1baf3b | 1816 | retval = exec_binprm(bprm); |
a6f76f23 DH |
1817 | if (retval < 0) |
1818 | goto out; | |
1da177e4 | 1819 | |
a6f76f23 | 1820 | /* execve succeeded */ |
498052bb | 1821 | current->fs->in_exec = 0; |
f9ce1f1c | 1822 | current->in_execve = 0; |
a6f76f23 | 1823 | acct_update_integrals(current); |
82727018 | 1824 | task_numa_free(current); |
a6f76f23 | 1825 | free_bprm(bprm); |
51f39a1f | 1826 | kfree(pathbuf); |
c4ad8f98 | 1827 | putname(filename); |
a6f76f23 DH |
1828 | if (displaced) |
1829 | put_files_struct(displaced); | |
1830 | return retval; | |
1da177e4 | 1831 | |
a6f76f23 | 1832 | out: |
3c77f845 ON |
1833 | if (bprm->mm) { |
1834 | acct_arg_size(bprm, 0); | |
1835 | mmput(bprm->mm); | |
1836 | } | |
1da177e4 | 1837 | |
498052bb | 1838 | out_unmark: |
9e00cdb0 | 1839 | current->fs->in_exec = 0; |
f9ce1f1c | 1840 | current->in_execve = 0; |
a6f76f23 DH |
1841 | |
1842 | out_free: | |
08a6fac1 | 1843 | free_bprm(bprm); |
51f39a1f | 1844 | kfree(pathbuf); |
1da177e4 | 1845 | |
fd8328be | 1846 | out_files: |
3b125388 AV |
1847 | if (displaced) |
1848 | reset_files_struct(displaced); | |
1da177e4 | 1849 | out_ret: |
c4ad8f98 | 1850 | putname(filename); |
1da177e4 LT |
1851 | return retval; |
1852 | } | |
1853 | ||
c4ad8f98 | 1854 | int do_execve(struct filename *filename, |
ba2d0162 | 1855 | const char __user *const __user *__argv, |
da3d4c5f | 1856 | const char __user *const __user *__envp) |
ba2d0162 | 1857 | { |
0e028465 ON |
1858 | struct user_arg_ptr argv = { .ptr.native = __argv }; |
1859 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
51f39a1f DD |
1860 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1861 | } | |
1862 | ||
1863 | int do_execveat(int fd, struct filename *filename, | |
1864 | const char __user *const __user *__argv, | |
1865 | const char __user *const __user *__envp, | |
1866 | int flags) | |
1867 | { | |
1868 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1869 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1870 | ||
1871 | return do_execveat_common(fd, filename, argv, envp, flags); | |
0e028465 ON |
1872 | } |
1873 | ||
1874 | #ifdef CONFIG_COMPAT | |
c4ad8f98 | 1875 | static int compat_do_execve(struct filename *filename, |
38b983b3 | 1876 | const compat_uptr_t __user *__argv, |
d03d26e5 | 1877 | const compat_uptr_t __user *__envp) |
0e028465 ON |
1878 | { |
1879 | struct user_arg_ptr argv = { | |
1880 | .is_compat = true, | |
1881 | .ptr.compat = __argv, | |
1882 | }; | |
1883 | struct user_arg_ptr envp = { | |
1884 | .is_compat = true, | |
1885 | .ptr.compat = __envp, | |
1886 | }; | |
51f39a1f DD |
1887 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1888 | } | |
1889 | ||
1890 | static int compat_do_execveat(int fd, struct filename *filename, | |
1891 | const compat_uptr_t __user *__argv, | |
1892 | const compat_uptr_t __user *__envp, | |
1893 | int flags) | |
1894 | { | |
1895 | struct user_arg_ptr argv = { | |
1896 | .is_compat = true, | |
1897 | .ptr.compat = __argv, | |
1898 | }; | |
1899 | struct user_arg_ptr envp = { | |
1900 | .is_compat = true, | |
1901 | .ptr.compat = __envp, | |
1902 | }; | |
1903 | return do_execveat_common(fd, filename, argv, envp, flags); | |
ba2d0162 | 1904 | } |
0e028465 | 1905 | #endif |
ba2d0162 | 1906 | |
964ee7df | 1907 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1908 | { |
801460d0 HS |
1909 | struct mm_struct *mm = current->mm; |
1910 | ||
1911 | if (mm->binfmt) | |
1912 | module_put(mm->binfmt->module); | |
1da177e4 | 1913 | |
801460d0 | 1914 | mm->binfmt = new; |
964ee7df ON |
1915 | if (new) |
1916 | __module_get(new->module); | |
1da177e4 | 1917 | } |
1da177e4 LT |
1918 | EXPORT_SYMBOL(set_binfmt); |
1919 | ||
6c5d5238 | 1920 | /* |
7288e118 | 1921 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. |
6c5d5238 KH |
1922 | */ |
1923 | void set_dumpable(struct mm_struct *mm, int value) | |
1924 | { | |
abacd2fe ON |
1925 | unsigned long old, new; |
1926 | ||
7288e118 ON |
1927 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) |
1928 | return; | |
1929 | ||
abacd2fe ON |
1930 | do { |
1931 | old = ACCESS_ONCE(mm->flags); | |
7288e118 | 1932 | new = (old & ~MMF_DUMPABLE_MASK) | value; |
abacd2fe | 1933 | } while (cmpxchg(&mm->flags, old, new) != old); |
6c5d5238 | 1934 | } |
6c5d5238 | 1935 | |
38b983b3 AV |
1936 | SYSCALL_DEFINE3(execve, |
1937 | const char __user *, filename, | |
1938 | const char __user *const __user *, argv, | |
1939 | const char __user *const __user *, envp) | |
1940 | { | |
c4ad8f98 | 1941 | return do_execve(getname(filename), argv, envp); |
38b983b3 | 1942 | } |
51f39a1f DD |
1943 | |
1944 | SYSCALL_DEFINE5(execveat, | |
1945 | int, fd, const char __user *, filename, | |
1946 | const char __user *const __user *, argv, | |
1947 | const char __user *const __user *, envp, | |
1948 | int, flags) | |
1949 | { | |
1950 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1951 | ||
1952 | return do_execveat(fd, | |
1953 | getname_flags(filename, lookup_flags, NULL), | |
1954 | argv, envp, flags); | |
1955 | } | |
1956 | ||
38b983b3 | 1957 | #ifdef CONFIG_COMPAT |
625b1d7e HC |
1958 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, |
1959 | const compat_uptr_t __user *, argv, | |
1960 | const compat_uptr_t __user *, envp) | |
38b983b3 | 1961 | { |
c4ad8f98 | 1962 | return compat_do_execve(getname(filename), argv, envp); |
38b983b3 | 1963 | } |
51f39a1f DD |
1964 | |
1965 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1966 | const char __user *, filename, | |
1967 | const compat_uptr_t __user *, argv, | |
1968 | const compat_uptr_t __user *, envp, | |
1969 | int, flags) | |
1970 | { | |
1971 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1972 | ||
1973 | return compat_do_execveat(fd, | |
1974 | getname_flags(filename, lookup_flags, NULL), | |
1975 | argv, envp, flags); | |
1976 | } | |
38b983b3 | 1977 | #endif |