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Commit | Line | Data |
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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> |
ca5b172b | 35 | #include <linux/pagemap.h> |
cdd6c482 | 36 | #include <linux/perf_event.h> |
1da177e4 LT |
37 | #include <linux/highmem.h> |
38 | #include <linux/spinlock.h> | |
39 | #include <linux/key.h> | |
40 | #include <linux/personality.h> | |
41 | #include <linux/binfmts.h> | |
1da177e4 | 42 | #include <linux/utsname.h> |
84d73786 | 43 | #include <linux/pid_namespace.h> |
1da177e4 LT |
44 | #include <linux/module.h> |
45 | #include <linux/namei.h> | |
1da177e4 LT |
46 | #include <linux/mount.h> |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
8f0ab514 | 49 | #include <linux/tsacct_kern.h> |
9f46080c | 50 | #include <linux/cn_proc.h> |
473ae30b | 51 | #include <linux/audit.h> |
6341c393 | 52 | #include <linux/tracehook.h> |
5f4123be | 53 | #include <linux/kmod.h> |
6110e3ab | 54 | #include <linux/fsnotify.h> |
5ad4e53b | 55 | #include <linux/fs_struct.h> |
61be228a | 56 | #include <linux/pipe_fs_i.h> |
3d5992d2 | 57 | #include <linux/oom.h> |
0e028465 | 58 | #include <linux/compat.h> |
b44a7dfc | 59 | #include <linux/vmalloc.h> |
1da177e4 | 60 | |
227e7746 SJR |
61 | #include <trace/events/fs.h> |
62 | ||
7c0f6ba6 | 63 | #include <linux/uaccess.h> |
1da177e4 | 64 | #include <asm/mmu_context.h> |
b6a2fea3 | 65 | #include <asm/tlb.h> |
43d2b113 KH |
66 | |
67 | #include <trace/events/task.h> | |
a6f76f23 | 68 | #include "internal.h" |
1da177e4 | 69 | |
4ff16c25 DS |
70 | #include <trace/events/sched.h> |
71 | ||
d6e71144 AC |
72 | int suid_dumpable = 0; |
73 | ||
e4dc1b14 | 74 | static LIST_HEAD(formats); |
1da177e4 LT |
75 | static DEFINE_RWLOCK(binfmt_lock); |
76 | ||
8fc3dc5a | 77 | void __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 78 | { |
8fc3dc5a | 79 | BUG_ON(!fmt); |
92eaa565 ON |
80 | if (WARN_ON(!fmt->load_binary)) |
81 | return; | |
1da177e4 | 82 | write_lock(&binfmt_lock); |
74641f58 IK |
83 | insert ? list_add(&fmt->lh, &formats) : |
84 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 | 85 | write_unlock(&binfmt_lock); |
1da177e4 LT |
86 | } |
87 | ||
74641f58 | 88 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 89 | |
f6b450d4 | 90 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 91 | { |
1da177e4 | 92 | write_lock(&binfmt_lock); |
e4dc1b14 | 93 | list_del(&fmt->lh); |
1da177e4 | 94 | write_unlock(&binfmt_lock); |
1da177e4 LT |
95 | } |
96 | ||
97 | EXPORT_SYMBOL(unregister_binfmt); | |
98 | ||
99 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
100 | { | |
101 | module_put(fmt->module); | |
102 | } | |
103 | ||
90f8572b EB |
104 | bool path_noexec(const struct path *path) |
105 | { | |
106 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
107 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
108 | } | |
e14748e8 | 109 | EXPORT_SYMBOL_GPL(path_noexec); |
90f8572b | 110 | |
8f060a31 SF |
111 | bool path_nosuid(const struct path *path) |
112 | { | |
113 | return !mnt_may_suid(path->mnt) || | |
114 | (path->mnt->mnt_sb->s_iflags & SB_I_NOSUID); | |
115 | } | |
116 | EXPORT_SYMBOL(path_nosuid); | |
117 | ||
69369a70 | 118 | #ifdef CONFIG_USELIB |
1da177e4 LT |
119 | /* |
120 | * Note that a shared library must be both readable and executable due to | |
121 | * security reasons. | |
122 | * | |
123 | * Also note that we take the address to load from from the file itself. | |
124 | */ | |
1e7bfb21 | 125 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 126 | { |
72c2d531 | 127 | struct linux_binfmt *fmt; |
964bd183 | 128 | struct file *file; |
91a27b2a | 129 | struct filename *tmp = getname(library); |
964bd183 | 130 | int error = PTR_ERR(tmp); |
47c805dc AV |
131 | static const struct open_flags uselib_flags = { |
132 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
62fb4a15 | 133 | .acc_mode = MAY_READ | MAY_EXEC, |
f9652e10 AV |
134 | .intent = LOOKUP_OPEN, |
135 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 136 | }; |
964bd183 | 137 | |
6e8341a1 AV |
138 | if (IS_ERR(tmp)) |
139 | goto out; | |
140 | ||
f9652e10 | 141 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); |
6e8341a1 AV |
142 | putname(tmp); |
143 | error = PTR_ERR(file); | |
144 | if (IS_ERR(file)) | |
1da177e4 LT |
145 | goto out; |
146 | ||
147 | error = -EINVAL; | |
496ad9aa | 148 | if (!S_ISREG(file_inode(file)->i_mode)) |
1da177e4 LT |
149 | goto exit; |
150 | ||
30524472 | 151 | error = -EACCES; |
90f8572b | 152 | if (path_noexec(&file->f_path)) |
1da177e4 LT |
153 | goto exit; |
154 | ||
2a12a9d7 | 155 | fsnotify_open(file); |
6110e3ab | 156 | |
1da177e4 | 157 | error = -ENOEXEC; |
1da177e4 | 158 | |
72c2d531 AV |
159 | read_lock(&binfmt_lock); |
160 | list_for_each_entry(fmt, &formats, lh) { | |
161 | if (!fmt->load_shlib) | |
162 | continue; | |
163 | if (!try_module_get(fmt->module)) | |
164 | continue; | |
1da177e4 | 165 | read_unlock(&binfmt_lock); |
72c2d531 AV |
166 | error = fmt->load_shlib(file); |
167 | read_lock(&binfmt_lock); | |
168 | put_binfmt(fmt); | |
169 | if (error != -ENOEXEC) | |
170 | break; | |
1da177e4 | 171 | } |
72c2d531 | 172 | read_unlock(&binfmt_lock); |
6e8341a1 | 173 | exit: |
1da177e4 LT |
174 | fput(file); |
175 | out: | |
176 | return error; | |
1da177e4 | 177 | } |
69369a70 | 178 | #endif /* #ifdef CONFIG_USELIB */ |
1da177e4 | 179 | |
b6a2fea3 | 180 | #ifdef CONFIG_MMU |
ae6b585e ON |
181 | /* |
182 | * The nascent bprm->mm is not visible until exec_mmap() but it can | |
183 | * use a lot of memory, account these pages in current->mm temporary | |
184 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we | |
185 | * change the counter back via acct_arg_size(0). | |
186 | */ | |
0e028465 | 187 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
188 | { |
189 | struct mm_struct *mm = current->mm; | |
190 | long diff = (long)(pages - bprm->vma_pages); | |
191 | ||
192 | if (!mm || !diff) | |
193 | return; | |
194 | ||
195 | bprm->vma_pages = pages; | |
3c77f845 | 196 | add_mm_counter(mm, MM_ANONPAGES, diff); |
3c77f845 ON |
197 | } |
198 | ||
0e028465 | 199 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
200 | int write) |
201 | { | |
202 | struct page *page; | |
203 | int ret; | |
9beae1ea | 204 | unsigned int gup_flags = FOLL_FORCE; |
b6a2fea3 OW |
205 | |
206 | #ifdef CONFIG_STACK_GROWSUP | |
207 | if (write) { | |
fe388e57 | 208 | ret = expand_downwards(bprm->vma, pos, 0); |
b6a2fea3 OW |
209 | if (ret < 0) |
210 | return NULL; | |
211 | } | |
212 | #endif | |
9beae1ea LS |
213 | |
214 | if (write) | |
215 | gup_flags |= FOLL_WRITE; | |
216 | ||
1e987790 DH |
217 | /* |
218 | * We are doing an exec(). 'current' is the process | |
219 | * doing the exec and bprm->mm is the new process's mm. | |
220 | */ | |
9beae1ea | 221 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, |
5b56d49f | 222 | &page, NULL, NULL); |
b6a2fea3 OW |
223 | if (ret <= 0) |
224 | return NULL; | |
225 | ||
226 | if (write) { | |
b6a2fea3 | 227 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
228 | struct rlimit *rlim; |
229 | ||
fe388e57 MH |
230 | /* |
231 | * GRWOSUP doesn't really have any gap at this stage because we grow | |
232 | * the stack down now. See the expand_downwards above. | |
233 | */ | |
234 | if (!IS_ENABLED(CONFIG_STACK_GROWSUP)) | |
235 | size -= stack_guard_gap; | |
3c77f845 ON |
236 | acct_arg_size(bprm, size / PAGE_SIZE); |
237 | ||
a64e715f LT |
238 | /* |
239 | * We've historically supported up to 32 pages (ARG_MAX) | |
240 | * of argument strings even with small stacks | |
241 | */ | |
242 | if (size <= ARG_MAX) | |
243 | return page; | |
b6a2fea3 OW |
244 | |
245 | /* | |
246 | * Limit to 1/4-th the stack size for the argv+env strings. | |
247 | * This ensures that: | |
248 | * - the remaining binfmt code will not run out of stack space, | |
249 | * - the program will have a reasonable amount of stack left | |
250 | * to work from. | |
251 | */ | |
a64e715f | 252 | rlim = current->signal->rlim; |
d554ed89 | 253 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
b6a2fea3 OW |
254 | put_page(page); |
255 | return NULL; | |
256 | } | |
257 | } | |
258 | ||
259 | return page; | |
260 | } | |
261 | ||
262 | static void put_arg_page(struct page *page) | |
263 | { | |
264 | put_page(page); | |
265 | } | |
266 | ||
b6a2fea3 OW |
267 | static void free_arg_pages(struct linux_binprm *bprm) |
268 | { | |
269 | } | |
270 | ||
271 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
272 | struct page *page) | |
273 | { | |
274 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
275 | } | |
276 | ||
277 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
278 | { | |
eaccbfa5 | 279 | int err; |
b6a2fea3 OW |
280 | struct vm_area_struct *vma = NULL; |
281 | struct mm_struct *mm = bprm->mm; | |
282 | ||
283 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
284 | if (!vma) | |
eaccbfa5 | 285 | return -ENOMEM; |
b6a2fea3 | 286 | |
f268dfe9 MH |
287 | if (down_write_killable(&mm->mmap_sem)) { |
288 | err = -EINTR; | |
289 | goto err_free; | |
290 | } | |
b6a2fea3 OW |
291 | vma->vm_mm = mm; |
292 | ||
293 | /* | |
294 | * Place the stack at the largest stack address the architecture | |
295 | * supports. Later, we'll move this to an appropriate place. We don't | |
296 | * use STACK_TOP because that can depend on attributes which aren't | |
297 | * configured yet. | |
298 | */ | |
aacb3d17 | 299 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
300 | vma->vm_end = STACK_TOP_MAX; |
301 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
d9104d1c | 302 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 303 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
5beb4930 | 304 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
462e635e | 305 | |
b6a2fea3 | 306 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 307 | if (err) |
b6a2fea3 | 308 | goto err; |
b6a2fea3 OW |
309 | |
310 | mm->stack_vm = mm->total_vm = 1; | |
fe3d197f | 311 | arch_bprm_mm_init(mm, vma); |
b6a2fea3 | 312 | up_write(&mm->mmap_sem); |
b6a2fea3 | 313 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 314 | return 0; |
b6a2fea3 | 315 | err: |
eaccbfa5 | 316 | up_write(&mm->mmap_sem); |
f268dfe9 | 317 | err_free: |
eaccbfa5 LFC |
318 | bprm->vma = NULL; |
319 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
320 | return err; |
321 | } | |
322 | ||
323 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
324 | { | |
325 | return len <= MAX_ARG_STRLEN; | |
326 | } | |
327 | ||
328 | #else | |
329 | ||
0e028465 | 330 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
331 | { |
332 | } | |
333 | ||
0e028465 | 334 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
335 | int write) |
336 | { | |
337 | struct page *page; | |
338 | ||
339 | page = bprm->page[pos / PAGE_SIZE]; | |
340 | if (!page && write) { | |
341 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
342 | if (!page) | |
343 | return NULL; | |
344 | bprm->page[pos / PAGE_SIZE] = page; | |
345 | } | |
346 | ||
347 | return page; | |
348 | } | |
349 | ||
350 | static void put_arg_page(struct page *page) | |
351 | { | |
352 | } | |
353 | ||
354 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
355 | { | |
356 | if (bprm->page[i]) { | |
357 | __free_page(bprm->page[i]); | |
358 | bprm->page[i] = NULL; | |
359 | } | |
360 | } | |
361 | ||
362 | static void free_arg_pages(struct linux_binprm *bprm) | |
363 | { | |
364 | int i; | |
365 | ||
366 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
367 | free_arg_page(bprm, i); | |
368 | } | |
369 | ||
370 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
371 | struct page *page) | |
372 | { | |
373 | } | |
374 | ||
375 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
376 | { | |
377 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
378 | return 0; | |
379 | } | |
380 | ||
381 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
382 | { | |
383 | return len <= bprm->p; | |
384 | } | |
385 | ||
386 | #endif /* CONFIG_MMU */ | |
387 | ||
388 | /* | |
389 | * Create a new mm_struct and populate it with a temporary stack | |
390 | * vm_area_struct. We don't have enough context at this point to set the stack | |
391 | * flags, permissions, and offset, so we use temporary values. We'll update | |
392 | * them later in setup_arg_pages(). | |
393 | */ | |
9cc64cea | 394 | static int bprm_mm_init(struct linux_binprm *bprm) |
b6a2fea3 OW |
395 | { |
396 | int err; | |
397 | struct mm_struct *mm = NULL; | |
398 | ||
399 | bprm->mm = mm = mm_alloc(); | |
400 | err = -ENOMEM; | |
401 | if (!mm) | |
402 | goto err; | |
403 | ||
b6a2fea3 OW |
404 | err = __bprm_mm_init(bprm); |
405 | if (err) | |
406 | goto err; | |
407 | ||
408 | return 0; | |
409 | ||
410 | err: | |
411 | if (mm) { | |
412 | bprm->mm = NULL; | |
413 | mmdrop(mm); | |
414 | } | |
415 | ||
416 | return err; | |
417 | } | |
418 | ||
ba2d0162 | 419 | struct user_arg_ptr { |
0e028465 ON |
420 | #ifdef CONFIG_COMPAT |
421 | bool is_compat; | |
422 | #endif | |
423 | union { | |
424 | const char __user *const __user *native; | |
425 | #ifdef CONFIG_COMPAT | |
38b983b3 | 426 | const compat_uptr_t __user *compat; |
0e028465 ON |
427 | #endif |
428 | } ptr; | |
ba2d0162 ON |
429 | }; |
430 | ||
431 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
1d1dbf81 | 432 | { |
0e028465 ON |
433 | const char __user *native; |
434 | ||
435 | #ifdef CONFIG_COMPAT | |
436 | if (unlikely(argv.is_compat)) { | |
437 | compat_uptr_t compat; | |
438 | ||
439 | if (get_user(compat, argv.ptr.compat + nr)) | |
440 | return ERR_PTR(-EFAULT); | |
1d1dbf81 | 441 | |
0e028465 ON |
442 | return compat_ptr(compat); |
443 | } | |
444 | #endif | |
445 | ||
446 | if (get_user(native, argv.ptr.native + nr)) | |
1d1dbf81 ON |
447 | return ERR_PTR(-EFAULT); |
448 | ||
0e028465 | 449 | return native; |
1d1dbf81 ON |
450 | } |
451 | ||
1da177e4 LT |
452 | /* |
453 | * count() counts the number of strings in array ARGV. | |
454 | */ | |
ba2d0162 | 455 | static int count(struct user_arg_ptr argv, int max) |
1da177e4 LT |
456 | { |
457 | int i = 0; | |
458 | ||
0e028465 | 459 | if (argv.ptr.native != NULL) { |
1da177e4 | 460 | for (;;) { |
1d1dbf81 | 461 | const char __user *p = get_user_arg_ptr(argv, i); |
1da177e4 | 462 | |
1da177e4 LT |
463 | if (!p) |
464 | break; | |
1d1dbf81 ON |
465 | |
466 | if (IS_ERR(p)) | |
467 | return -EFAULT; | |
468 | ||
6d92d4f6 | 469 | if (i >= max) |
1da177e4 | 470 | return -E2BIG; |
6d92d4f6 | 471 | ++i; |
9aea5a65 RM |
472 | |
473 | if (fatal_signal_pending(current)) | |
474 | return -ERESTARTNOHAND; | |
1da177e4 LT |
475 | cond_resched(); |
476 | } | |
477 | } | |
478 | return i; | |
479 | } | |
480 | ||
481 | /* | |
b6a2fea3 OW |
482 | * 'copy_strings()' copies argument/environment strings from the old |
483 | * processes's memory to the new process's stack. The call to get_user_pages() | |
484 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 485 | */ |
ba2d0162 | 486 | static int copy_strings(int argc, struct user_arg_ptr argv, |
75c96f85 | 487 | struct linux_binprm *bprm) |
1da177e4 LT |
488 | { |
489 | struct page *kmapped_page = NULL; | |
490 | char *kaddr = NULL; | |
b6a2fea3 | 491 | unsigned long kpos = 0; |
1da177e4 LT |
492 | int ret; |
493 | ||
494 | while (argc-- > 0) { | |
d7627467 | 495 | const char __user *str; |
1da177e4 LT |
496 | int len; |
497 | unsigned long pos; | |
498 | ||
1d1dbf81 ON |
499 | ret = -EFAULT; |
500 | str = get_user_arg_ptr(argv, argc); | |
501 | if (IS_ERR(str)) | |
1da177e4 | 502 | goto out; |
1da177e4 | 503 | |
1d1dbf81 ON |
504 | len = strnlen_user(str, MAX_ARG_STRLEN); |
505 | if (!len) | |
506 | goto out; | |
507 | ||
508 | ret = -E2BIG; | |
509 | if (!valid_arg_len(bprm, len)) | |
1da177e4 | 510 | goto out; |
1da177e4 | 511 | |
b6a2fea3 | 512 | /* We're going to work our way backwords. */ |
1da177e4 | 513 | pos = bprm->p; |
b6a2fea3 OW |
514 | str += len; |
515 | bprm->p -= len; | |
1da177e4 LT |
516 | |
517 | while (len > 0) { | |
1da177e4 | 518 | int offset, bytes_to_copy; |
1da177e4 | 519 | |
9aea5a65 RM |
520 | if (fatal_signal_pending(current)) { |
521 | ret = -ERESTARTNOHAND; | |
522 | goto out; | |
523 | } | |
7993bc1f RM |
524 | cond_resched(); |
525 | ||
1da177e4 | 526 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
527 | if (offset == 0) |
528 | offset = PAGE_SIZE; | |
529 | ||
530 | bytes_to_copy = offset; | |
531 | if (bytes_to_copy > len) | |
532 | bytes_to_copy = len; | |
533 | ||
534 | offset -= bytes_to_copy; | |
535 | pos -= bytes_to_copy; | |
536 | str -= bytes_to_copy; | |
537 | len -= bytes_to_copy; | |
538 | ||
539 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
540 | struct page *page; | |
541 | ||
542 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 543 | if (!page) { |
b6a2fea3 | 544 | ret = -E2BIG; |
1da177e4 LT |
545 | goto out; |
546 | } | |
1da177e4 | 547 | |
b6a2fea3 OW |
548 | if (kmapped_page) { |
549 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 550 | kunmap(kmapped_page); |
b6a2fea3 OW |
551 | put_arg_page(kmapped_page); |
552 | } | |
1da177e4 LT |
553 | kmapped_page = page; |
554 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
555 | kpos = pos & PAGE_MASK; |
556 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 557 | } |
b6a2fea3 | 558 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
559 | ret = -EFAULT; |
560 | goto out; | |
561 | } | |
1da177e4 LT |
562 | } |
563 | } | |
564 | ret = 0; | |
565 | out: | |
b6a2fea3 OW |
566 | if (kmapped_page) { |
567 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 568 | kunmap(kmapped_page); |
b6a2fea3 OW |
569 | put_arg_page(kmapped_page); |
570 | } | |
1da177e4 LT |
571 | return ret; |
572 | } | |
573 | ||
574 | /* | |
575 | * Like copy_strings, but get argv and its values from kernel memory. | |
576 | */ | |
ba2d0162 | 577 | int copy_strings_kernel(int argc, const char *const *__argv, |
d7627467 | 578 | struct linux_binprm *bprm) |
1da177e4 LT |
579 | { |
580 | int r; | |
581 | mm_segment_t oldfs = get_fs(); | |
ba2d0162 | 582 | struct user_arg_ptr argv = { |
0e028465 | 583 | .ptr.native = (const char __user *const __user *)__argv, |
ba2d0162 ON |
584 | }; |
585 | ||
1da177e4 | 586 | set_fs(KERNEL_DS); |
ba2d0162 | 587 | r = copy_strings(argc, argv, bprm); |
1da177e4 | 588 | set_fs(oldfs); |
ba2d0162 | 589 | |
1da177e4 LT |
590 | return r; |
591 | } | |
1da177e4 LT |
592 | EXPORT_SYMBOL(copy_strings_kernel); |
593 | ||
594 | #ifdef CONFIG_MMU | |
b6a2fea3 | 595 | |
1da177e4 | 596 | /* |
b6a2fea3 OW |
597 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
598 | * the binfmt code determines where the new stack should reside, we shift it to | |
599 | * its final location. The process proceeds as follows: | |
1da177e4 | 600 | * |
b6a2fea3 OW |
601 | * 1) Use shift to calculate the new vma endpoints. |
602 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
603 | * arguments passed to subsequent functions are consistent. | |
604 | * 3) Move vma's page tables to the new range. | |
605 | * 4) Free up any cleared pgd range. | |
606 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 607 | */ |
b6a2fea3 | 608 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
609 | { |
610 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
611 | unsigned long old_start = vma->vm_start; |
612 | unsigned long old_end = vma->vm_end; | |
613 | unsigned long length = old_end - old_start; | |
614 | unsigned long new_start = old_start - shift; | |
615 | unsigned long new_end = old_end - shift; | |
d16dfc55 | 616 | struct mmu_gather tlb; |
1da177e4 | 617 | |
b6a2fea3 | 618 | BUG_ON(new_start > new_end); |
1da177e4 | 619 | |
b6a2fea3 OW |
620 | /* |
621 | * ensure there are no vmas between where we want to go | |
622 | * and where we are | |
623 | */ | |
624 | if (vma != find_vma(mm, new_start)) | |
625 | return -EFAULT; | |
626 | ||
627 | /* | |
628 | * cover the whole range: [new_start, old_end) | |
629 | */ | |
5beb4930 RR |
630 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
631 | return -ENOMEM; | |
b6a2fea3 OW |
632 | |
633 | /* | |
634 | * move the page tables downwards, on failure we rely on | |
635 | * process cleanup to remove whatever mess we made. | |
636 | */ | |
637 | if (length != move_page_tables(vma, old_start, | |
38a76013 | 638 | vma, new_start, length, false)) |
b6a2fea3 OW |
639 | return -ENOMEM; |
640 | ||
641 | lru_add_drain(); | |
2b047252 | 642 | tlb_gather_mmu(&tlb, mm, old_start, old_end); |
b6a2fea3 OW |
643 | if (new_end > old_start) { |
644 | /* | |
645 | * when the old and new regions overlap clear from new_end. | |
646 | */ | |
d16dfc55 | 647 | free_pgd_range(&tlb, new_end, old_end, new_end, |
6ee8630e | 648 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
b6a2fea3 OW |
649 | } else { |
650 | /* | |
651 | * otherwise, clean from old_start; this is done to not touch | |
652 | * the address space in [new_end, old_start) some architectures | |
653 | * have constraints on va-space that make this illegal (IA64) - | |
654 | * for the others its just a little faster. | |
655 | */ | |
d16dfc55 | 656 | free_pgd_range(&tlb, old_start, old_end, new_end, |
6ee8630e | 657 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
1da177e4 | 658 | } |
2b047252 | 659 | tlb_finish_mmu(&tlb, old_start, old_end); |
b6a2fea3 OW |
660 | |
661 | /* | |
5beb4930 | 662 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
663 | */ |
664 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
665 | ||
666 | return 0; | |
1da177e4 LT |
667 | } |
668 | ||
b6a2fea3 OW |
669 | /* |
670 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
671 | * the stack is optionally relocated, and some extra space is added. | |
672 | */ | |
1da177e4 LT |
673 | int setup_arg_pages(struct linux_binprm *bprm, |
674 | unsigned long stack_top, | |
675 | int executable_stack) | |
676 | { | |
b6a2fea3 OW |
677 | unsigned long ret; |
678 | unsigned long stack_shift; | |
1da177e4 | 679 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
680 | struct vm_area_struct *vma = bprm->vma; |
681 | struct vm_area_struct *prev = NULL; | |
682 | unsigned long vm_flags; | |
683 | unsigned long stack_base; | |
803bf5ec MN |
684 | unsigned long stack_size; |
685 | unsigned long stack_expand; | |
686 | unsigned long rlim_stack; | |
1da177e4 LT |
687 | |
688 | #ifdef CONFIG_STACK_GROWSUP | |
d71f290b | 689 | /* Limit stack size */ |
d554ed89 | 690 | stack_base = rlimit_max(RLIMIT_STACK); |
d71f290b JH |
691 | if (stack_base > STACK_SIZE_MAX) |
692 | stack_base = STACK_SIZE_MAX; | |
1da177e4 | 693 | |
d045c77c HD |
694 | /* Add space for stack randomization. */ |
695 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
696 | ||
b6a2fea3 OW |
697 | /* Make sure we didn't let the argument array grow too large. */ |
698 | if (vma->vm_end - vma->vm_start > stack_base) | |
699 | return -ENOMEM; | |
1da177e4 | 700 | |
b6a2fea3 | 701 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 702 | |
b6a2fea3 OW |
703 | stack_shift = vma->vm_start - stack_base; |
704 | mm->arg_start = bprm->p - stack_shift; | |
705 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 706 | #else |
b6a2fea3 OW |
707 | stack_top = arch_align_stack(stack_top); |
708 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
709 | |
710 | if (unlikely(stack_top < mmap_min_addr) || | |
711 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
712 | return -ENOMEM; | |
713 | ||
b6a2fea3 OW |
714 | stack_shift = vma->vm_end - stack_top; |
715 | ||
716 | bprm->p -= stack_shift; | |
1da177e4 | 717 | mm->arg_start = bprm->p; |
1da177e4 LT |
718 | #endif |
719 | ||
1da177e4 | 720 | if (bprm->loader) |
b6a2fea3 OW |
721 | bprm->loader -= stack_shift; |
722 | bprm->exec -= stack_shift; | |
1da177e4 | 723 | |
f268dfe9 MH |
724 | if (down_write_killable(&mm->mmap_sem)) |
725 | return -EINTR; | |
726 | ||
96a8e13e | 727 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
728 | |
729 | /* | |
730 | * Adjust stack execute permissions; explicitly enable for | |
731 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
732 | * (arch default) otherwise. | |
733 | */ | |
734 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
735 | vm_flags |= VM_EXEC; | |
736 | else if (executable_stack == EXSTACK_DISABLE_X) | |
737 | vm_flags &= ~VM_EXEC; | |
738 | vm_flags |= mm->def_flags; | |
a8bef8ff | 739 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
740 | |
741 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
742 | vm_flags); | |
743 | if (ret) | |
744 | goto out_unlock; | |
745 | BUG_ON(prev != vma); | |
746 | ||
747 | /* Move stack pages down in memory. */ | |
748 | if (stack_shift) { | |
749 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
750 | if (ret) |
751 | goto out_unlock; | |
1da177e4 LT |
752 | } |
753 | ||
a8bef8ff MG |
754 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
755 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
756 | ||
5ef097dd | 757 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
758 | stack_size = vma->vm_end - vma->vm_start; |
759 | /* | |
760 | * Align this down to a page boundary as expand_stack | |
761 | * will align it up. | |
762 | */ | |
763 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
b6a2fea3 | 764 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
765 | if (stack_size + stack_expand > rlim_stack) |
766 | stack_base = vma->vm_start + rlim_stack; | |
767 | else | |
768 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 769 | #else |
803bf5ec MN |
770 | if (stack_size + stack_expand > rlim_stack) |
771 | stack_base = vma->vm_end - rlim_stack; | |
772 | else | |
773 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 774 | #endif |
3af9e859 | 775 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
776 | ret = expand_stack(vma, stack_base); |
777 | if (ret) | |
778 | ret = -EFAULT; | |
779 | ||
780 | out_unlock: | |
1da177e4 | 781 | up_write(&mm->mmap_sem); |
fc63cf23 | 782 | return ret; |
1da177e4 | 783 | } |
1da177e4 LT |
784 | EXPORT_SYMBOL(setup_arg_pages); |
785 | ||
7e7ec6a9 NP |
786 | #else |
787 | ||
788 | /* | |
789 | * Transfer the program arguments and environment from the holding pages | |
790 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
791 | */ | |
792 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
793 | unsigned long *sp_location) | |
794 | { | |
795 | unsigned long index, stop, sp; | |
796 | int ret = 0; | |
797 | ||
798 | stop = bprm->p >> PAGE_SHIFT; | |
799 | sp = *sp_location; | |
800 | ||
801 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
802 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
803 | char *src = kmap(bprm->page[index]) + offset; | |
804 | sp -= PAGE_SIZE - offset; | |
805 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
806 | ret = -EFAULT; | |
807 | kunmap(bprm->page[index]); | |
808 | if (ret) | |
809 | goto out; | |
810 | } | |
811 | ||
812 | *sp_location = sp; | |
813 | ||
814 | out: | |
815 | return ret; | |
816 | } | |
817 | EXPORT_SYMBOL(transfer_args_to_stack); | |
818 | ||
1da177e4 LT |
819 | #endif /* CONFIG_MMU */ |
820 | ||
51f39a1f | 821 | static struct file *do_open_execat(int fd, struct filename *name, int flags) |
1da177e4 | 822 | { |
1da177e4 | 823 | struct file *file; |
e56b6a5d | 824 | int err; |
51f39a1f | 825 | struct open_flags open_exec_flags = { |
47c805dc | 826 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
62fb4a15 | 827 | .acc_mode = MAY_EXEC, |
f9652e10 AV |
828 | .intent = LOOKUP_OPEN, |
829 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 830 | }; |
1da177e4 | 831 | |
51f39a1f DD |
832 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
833 | return ERR_PTR(-EINVAL); | |
834 | if (flags & AT_SYMLINK_NOFOLLOW) | |
835 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
836 | if (flags & AT_EMPTY_PATH) | |
837 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
838 | ||
839 | file = do_filp_open(fd, name, &open_exec_flags); | |
6e8341a1 | 840 | if (IS_ERR(file)) |
e56b6a5d CH |
841 | goto out; |
842 | ||
843 | err = -EACCES; | |
496ad9aa | 844 | if (!S_ISREG(file_inode(file)->i_mode)) |
6e8341a1 | 845 | goto exit; |
e56b6a5d | 846 | |
90f8572b | 847 | if (path_noexec(&file->f_path)) |
6e8341a1 | 848 | goto exit; |
e56b6a5d CH |
849 | |
850 | err = deny_write_access(file); | |
6e8341a1 AV |
851 | if (err) |
852 | goto exit; | |
1da177e4 | 853 | |
51f39a1f DD |
854 | if (name->name[0] != '\0') |
855 | fsnotify_open(file); | |
856 | ||
227e7746 SJR |
857 | trace_open_exec(name->name); |
858 | ||
6e8341a1 | 859 | out: |
e56b6a5d CH |
860 | return file; |
861 | ||
6e8341a1 AV |
862 | exit: |
863 | fput(file); | |
e56b6a5d CH |
864 | return ERR_PTR(err); |
865 | } | |
c4ad8f98 LT |
866 | |
867 | struct file *open_exec(const char *name) | |
868 | { | |
51689104 PM |
869 | struct filename *filename = getname_kernel(name); |
870 | struct file *f = ERR_CAST(filename); | |
871 | ||
872 | if (!IS_ERR(filename)) { | |
873 | f = do_open_execat(AT_FDCWD, filename, 0); | |
874 | putname(filename); | |
875 | } | |
876 | return f; | |
c4ad8f98 | 877 | } |
1da177e4 LT |
878 | EXPORT_SYMBOL(open_exec); |
879 | ||
6777d773 MZ |
880 | int kernel_read(struct file *file, loff_t offset, |
881 | char *addr, unsigned long count) | |
1da177e4 LT |
882 | { |
883 | mm_segment_t old_fs; | |
884 | loff_t pos = offset; | |
885 | int result; | |
886 | ||
887 | old_fs = get_fs(); | |
888 | set_fs(get_ds()); | |
889 | /* The cast to a user pointer is valid due to the set_fs() */ | |
890 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
891 | set_fs(old_fs); | |
892 | return result; | |
893 | } | |
894 | ||
895 | EXPORT_SYMBOL(kernel_read); | |
896 | ||
b44a7dfc | 897 | int kernel_read_file(struct file *file, void **buf, loff_t *size, |
bc8ca5b9 | 898 | loff_t max_size, enum kernel_read_file_id id) |
b44a7dfc MZ |
899 | { |
900 | loff_t i_size, pos; | |
901 | ssize_t bytes = 0; | |
902 | int ret; | |
903 | ||
904 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
905 | return -EINVAL; | |
906 | ||
39eeb4fb MZ |
907 | ret = security_kernel_read_file(file, id); |
908 | if (ret) | |
909 | return ret; | |
910 | ||
39d637af DK |
911 | ret = deny_write_access(file); |
912 | if (ret) | |
913 | return ret; | |
914 | ||
b44a7dfc | 915 | i_size = i_size_read(file_inode(file)); |
39d637af DK |
916 | if (max_size > 0 && i_size > max_size) { |
917 | ret = -EFBIG; | |
918 | goto out; | |
919 | } | |
920 | if (i_size <= 0) { | |
921 | ret = -EINVAL; | |
922 | goto out; | |
923 | } | |
b44a7dfc | 924 | |
a098ecd2 SB |
925 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) |
926 | *buf = vmalloc(i_size); | |
39d637af DK |
927 | if (!*buf) { |
928 | ret = -ENOMEM; | |
929 | goto out; | |
930 | } | |
b44a7dfc MZ |
931 | |
932 | pos = 0; | |
933 | while (pos < i_size) { | |
934 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
935 | i_size - pos); | |
936 | if (bytes < 0) { | |
937 | ret = bytes; | |
938 | goto out; | |
939 | } | |
940 | ||
941 | if (bytes == 0) | |
942 | break; | |
943 | pos += bytes; | |
944 | } | |
945 | ||
946 | if (pos != i_size) { | |
947 | ret = -EIO; | |
39d637af | 948 | goto out_free; |
b44a7dfc MZ |
949 | } |
950 | ||
bc8ca5b9 | 951 | ret = security_kernel_post_read_file(file, *buf, i_size, id); |
b44a7dfc MZ |
952 | if (!ret) |
953 | *size = pos; | |
954 | ||
39d637af | 955 | out_free: |
b44a7dfc | 956 | if (ret < 0) { |
a098ecd2 SB |
957 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { |
958 | vfree(*buf); | |
959 | *buf = NULL; | |
960 | } | |
b44a7dfc | 961 | } |
39d637af DK |
962 | |
963 | out: | |
964 | allow_write_access(file); | |
b44a7dfc MZ |
965 | return ret; |
966 | } | |
967 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
968 | ||
09596b94 MZ |
969 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, |
970 | loff_t max_size, enum kernel_read_file_id id) | |
971 | { | |
972 | struct file *file; | |
973 | int ret; | |
974 | ||
975 | if (!path || !*path) | |
976 | return -EINVAL; | |
977 | ||
978 | file = filp_open(path, O_RDONLY, 0); | |
979 | if (IS_ERR(file)) | |
980 | return PTR_ERR(file); | |
981 | ||
982 | ret = kernel_read_file(file, buf, size, max_size, id); | |
983 | fput(file); | |
984 | return ret; | |
985 | } | |
986 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
987 | ||
b844f0ec MZ |
988 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, |
989 | enum kernel_read_file_id id) | |
990 | { | |
991 | struct fd f = fdget(fd); | |
992 | int ret = -EBADF; | |
993 | ||
994 | if (!f.file) | |
995 | goto out; | |
996 | ||
997 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
998 | out: | |
999 | fdput(f); | |
1000 | return ret; | |
1001 | } | |
1002 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
1003 | ||
3dc20cb2 AV |
1004 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) |
1005 | { | |
ec695579 | 1006 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); |
3dc20cb2 AV |
1007 | if (res > 0) |
1008 | flush_icache_range(addr, addr + len); | |
1009 | return res; | |
1010 | } | |
1011 | EXPORT_SYMBOL(read_code); | |
1012 | ||
1da177e4 LT |
1013 | static int exec_mmap(struct mm_struct *mm) |
1014 | { | |
1015 | struct task_struct *tsk; | |
615d6e87 | 1016 | struct mm_struct *old_mm, *active_mm; |
1da177e4 LT |
1017 | |
1018 | /* Notify parent that we're no longer interested in the old VM */ | |
1019 | tsk = current; | |
1020 | old_mm = current->mm; | |
1021 | mm_release(tsk, old_mm); | |
1022 | ||
1023 | if (old_mm) { | |
4fe7efdb | 1024 | sync_mm_rss(old_mm); |
1da177e4 LT |
1025 | /* |
1026 | * Make sure that if there is a core dump in progress | |
1027 | * for the old mm, we get out and die instead of going | |
1028 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 1029 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
1030 | */ |
1031 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 1032 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
1033 | up_read(&old_mm->mmap_sem); |
1034 | return -EINTR; | |
1035 | } | |
1036 | } | |
1037 | task_lock(tsk); | |
1038 | active_mm = tsk->active_mm; | |
1039 | tsk->mm = mm; | |
1040 | tsk->active_mm = mm; | |
1041 | activate_mm(active_mm, mm); | |
615d6e87 DB |
1042 | tsk->mm->vmacache_seqnum = 0; |
1043 | vmacache_flush(tsk); | |
1da177e4 | 1044 | task_unlock(tsk); |
1da177e4 LT |
1045 | if (old_mm) { |
1046 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 1047 | BUG_ON(active_mm != old_mm); |
701085b2 | 1048 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
31a78f23 | 1049 | mm_update_next_owner(old_mm); |
1da177e4 LT |
1050 | mmput(old_mm); |
1051 | return 0; | |
1052 | } | |
1053 | mmdrop(active_mm); | |
1054 | return 0; | |
1055 | } | |
1056 | ||
1057 | /* | |
1058 | * This function makes sure the current process has its own signal table, | |
1059 | * so that flush_signal_handlers can later reset the handlers without | |
1060 | * disturbing other processes. (Other processes might share the signal | |
1061 | * table via the CLONE_SIGHAND option to clone().) | |
1062 | */ | |
858119e1 | 1063 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
1064 | { |
1065 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 1066 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 1067 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 1068 | |
aafe6c2a | 1069 | if (thread_group_empty(tsk)) |
1da177e4 LT |
1070 | goto no_thread_group; |
1071 | ||
1072 | /* | |
1073 | * Kill all other threads in the thread group. | |
1da177e4 | 1074 | */ |
1da177e4 | 1075 | spin_lock_irq(lock); |
ed5d2cac | 1076 | if (signal_group_exit(sig)) { |
1da177e4 LT |
1077 | /* |
1078 | * Another group action in progress, just | |
1079 | * return so that the signal is processed. | |
1080 | */ | |
1081 | spin_unlock_irq(lock); | |
1da177e4 LT |
1082 | return -EAGAIN; |
1083 | } | |
d344193a | 1084 | |
ed5d2cac | 1085 | sig->group_exit_task = tsk; |
d344193a ON |
1086 | sig->notify_count = zap_other_threads(tsk); |
1087 | if (!thread_group_leader(tsk)) | |
1088 | sig->notify_count--; | |
1da177e4 | 1089 | |
d344193a | 1090 | while (sig->notify_count) { |
d5bbd43d | 1091 | __set_current_state(TASK_KILLABLE); |
1da177e4 LT |
1092 | spin_unlock_irq(lock); |
1093 | schedule(); | |
d5bbd43d ON |
1094 | if (unlikely(__fatal_signal_pending(tsk))) |
1095 | goto killed; | |
1da177e4 LT |
1096 | spin_lock_irq(lock); |
1097 | } | |
1da177e4 LT |
1098 | spin_unlock_irq(lock); |
1099 | ||
1100 | /* | |
1101 | * At this point all other threads have exited, all we have to | |
1102 | * do is to wait for the thread group leader to become inactive, | |
1103 | * and to assume its PID: | |
1104 | */ | |
aafe6c2a | 1105 | if (!thread_group_leader(tsk)) { |
8187926b | 1106 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 1107 | |
6db840fa | 1108 | for (;;) { |
e56fb287 | 1109 | threadgroup_change_begin(tsk); |
6db840fa | 1110 | write_lock_irq(&tasklist_lock); |
dfcce791 KT |
1111 | /* |
1112 | * Do this under tasklist_lock to ensure that | |
1113 | * exit_notify() can't miss ->group_exit_task | |
1114 | */ | |
1115 | sig->notify_count = -1; | |
6db840fa ON |
1116 | if (likely(leader->exit_state)) |
1117 | break; | |
d5bbd43d | 1118 | __set_current_state(TASK_KILLABLE); |
6db840fa | 1119 | write_unlock_irq(&tasklist_lock); |
e56fb287 | 1120 | threadgroup_change_end(tsk); |
6db840fa | 1121 | schedule(); |
d5bbd43d ON |
1122 | if (unlikely(__fatal_signal_pending(tsk))) |
1123 | goto killed; | |
6db840fa | 1124 | } |
1da177e4 | 1125 | |
f5e90281 RM |
1126 | /* |
1127 | * The only record we have of the real-time age of a | |
1128 | * process, regardless of execs it's done, is start_time. | |
1129 | * All the past CPU time is accumulated in signal_struct | |
1130 | * from sister threads now dead. But in this non-leader | |
1131 | * exec, nothing survives from the original leader thread, | |
1132 | * whose birth marks the true age of this process now. | |
1133 | * When we take on its identity by switching to its PID, we | |
1134 | * also take its birthdate (always earlier than our own). | |
1135 | */ | |
aafe6c2a | 1136 | tsk->start_time = leader->start_time; |
266b7a02 | 1137 | tsk->real_start_time = leader->real_start_time; |
f5e90281 | 1138 | |
bac0abd6 PE |
1139 | BUG_ON(!same_thread_group(leader, tsk)); |
1140 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
1141 | /* |
1142 | * An exec() starts a new thread group with the | |
1143 | * TGID of the previous thread group. Rehash the | |
1144 | * two threads with a switched PID, and release | |
1145 | * the former thread group leader: | |
1146 | */ | |
d73d6529 EB |
1147 | |
1148 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
1149 | * The old leader becomes a thread of the this thread group. |
1150 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
1151 | * is called. Odd but simple and correct. |
1152 | */ | |
aafe6c2a | 1153 | tsk->pid = leader->pid; |
3f418548 | 1154 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
1155 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
1156 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 1157 | |
aafe6c2a | 1158 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 1159 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 1160 | |
aafe6c2a EB |
1161 | tsk->group_leader = tsk; |
1162 | leader->group_leader = tsk; | |
de12a787 | 1163 | |
aafe6c2a | 1164 | tsk->exit_signal = SIGCHLD; |
087806b1 | 1165 | leader->exit_signal = -1; |
962b564c ON |
1166 | |
1167 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1168 | leader->exit_state = EXIT_DEAD; | |
eac1b5e5 ON |
1169 | |
1170 | /* | |
1171 | * We are going to release_task()->ptrace_unlink() silently, | |
1172 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1173 | * the tracer wont't block again waiting for this thread. | |
1174 | */ | |
1175 | if (unlikely(leader->ptrace)) | |
1176 | __wake_up_parent(leader, leader->parent); | |
1da177e4 | 1177 | write_unlock_irq(&tasklist_lock); |
e56fb287 | 1178 | threadgroup_change_end(tsk); |
8187926b ON |
1179 | |
1180 | release_task(leader); | |
ed5d2cac | 1181 | } |
1da177e4 | 1182 | |
6db840fa ON |
1183 | sig->group_exit_task = NULL; |
1184 | sig->notify_count = 0; | |
1da177e4 LT |
1185 | |
1186 | no_thread_group: | |
e6368253 ON |
1187 | /* we have changed execution domain */ |
1188 | tsk->exit_signal = SIGCHLD; | |
1189 | ||
baa73d9e | 1190 | #ifdef CONFIG_POSIX_TIMERS |
1da177e4 | 1191 | exit_itimers(sig); |
cbaffba1 | 1192 | flush_itimer_signals(); |
baa73d9e | 1193 | #endif |
329f7dba | 1194 | |
b2c903b8 ON |
1195 | if (atomic_read(&oldsighand->count) != 1) { |
1196 | struct sighand_struct *newsighand; | |
1da177e4 | 1197 | /* |
b2c903b8 ON |
1198 | * This ->sighand is shared with the CLONE_SIGHAND |
1199 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 1200 | */ |
b2c903b8 ON |
1201 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
1202 | if (!newsighand) | |
1203 | return -ENOMEM; | |
1204 | ||
1da177e4 LT |
1205 | atomic_set(&newsighand->count, 1); |
1206 | memcpy(newsighand->action, oldsighand->action, | |
1207 | sizeof(newsighand->action)); | |
1208 | ||
1209 | write_lock_irq(&tasklist_lock); | |
1210 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 1211 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
1212 | spin_unlock(&oldsighand->siglock); |
1213 | write_unlock_irq(&tasklist_lock); | |
1214 | ||
fba2afaa | 1215 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
1216 | } |
1217 | ||
aafe6c2a | 1218 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 | 1219 | return 0; |
d5bbd43d ON |
1220 | |
1221 | killed: | |
1222 | /* protects against exit_notify() and __exit_signal() */ | |
1223 | read_lock(&tasklist_lock); | |
1224 | sig->group_exit_task = NULL; | |
1225 | sig->notify_count = 0; | |
1226 | read_unlock(&tasklist_lock); | |
1227 | return -EAGAIN; | |
1da177e4 | 1228 | } |
0840a90d | 1229 | |
59714d65 | 1230 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
1231 | { |
1232 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1233 | task_lock(tsk); | |
1234 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1235 | task_unlock(tsk); | |
59714d65 | 1236 | return buf; |
1da177e4 | 1237 | } |
7d74f492 | 1238 | EXPORT_SYMBOL_GPL(get_task_comm); |
1da177e4 | 1239 | |
6a6d27de AV |
1240 | /* |
1241 | * These functions flushes out all traces of the currently running executable | |
1242 | * so that a new one can be started | |
1243 | */ | |
1244 | ||
82b89778 | 1245 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) |
1da177e4 LT |
1246 | { |
1247 | task_lock(tsk); | |
43d2b113 | 1248 | trace_task_rename(tsk, buf); |
1da177e4 LT |
1249 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1250 | task_unlock(tsk); | |
82b89778 | 1251 | perf_event_comm(tsk, exec); |
1da177e4 LT |
1252 | } |
1253 | ||
1254 | int flush_old_exec(struct linux_binprm * bprm) | |
1255 | { | |
221af7f8 | 1256 | int retval; |
1da177e4 LT |
1257 | |
1258 | /* | |
1259 | * Make sure we have a private signal table and that | |
1260 | * we are unassociated from the previous thread group. | |
1261 | */ | |
1262 | retval = de_thread(current); | |
1263 | if (retval) | |
1264 | goto out; | |
1265 | ||
6e399cd1 DB |
1266 | /* |
1267 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1268 | * not visibile until then. This also enables the update | |
1269 | * to be lockless. | |
1270 | */ | |
925d1c40 | 1271 | set_mm_exe_file(bprm->mm, bprm->file); |
6e399cd1 | 1272 | |
1da177e4 LT |
1273 | /* |
1274 | * Release all of the old mmap stuff | |
1275 | */ | |
3c77f845 | 1276 | acct_arg_size(bprm, 0); |
1da177e4 LT |
1277 | retval = exec_mmap(bprm->mm); |
1278 | if (retval) | |
fd8328be | 1279 | goto out; |
1da177e4 LT |
1280 | |
1281 | bprm->mm = NULL; /* We're using it now */ | |
7ab02af4 | 1282 | |
dac853ae | 1283 | set_fs(USER_DS); |
b88fae64 ZY |
1284 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | |
1285 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
7ab02af4 LT |
1286 | flush_thread(); |
1287 | current->personality &= ~bprm->per_clear; | |
1288 | ||
613cc2b6 AS |
1289 | /* |
1290 | * We have to apply CLOEXEC before we change whether the process is | |
1291 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1292 | * trying to access the should-be-closed file descriptors of a process | |
1293 | * undergoing exec(2). | |
1294 | */ | |
1295 | do_close_on_exec(current->files); | |
221af7f8 LT |
1296 | return 0; |
1297 | ||
1298 | out: | |
1299 | return retval; | |
1300 | } | |
1301 | EXPORT_SYMBOL(flush_old_exec); | |
1302 | ||
1b5d783c AV |
1303 | void would_dump(struct linux_binprm *bprm, struct file *file) |
1304 | { | |
f84df2a6 EB |
1305 | struct inode *inode = file_inode(file); |
1306 | if (inode_permission(inode, MAY_READ) < 0) { | |
1307 | struct user_namespace *old, *user_ns; | |
1b5d783c | 1308 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
f84df2a6 EB |
1309 | |
1310 | /* Ensure mm->user_ns contains the executable */ | |
1311 | user_ns = old = bprm->mm->user_ns; | |
1312 | while ((user_ns != &init_user_ns) && | |
1313 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1314 | user_ns = user_ns->parent; | |
1315 | ||
1316 | if (old != user_ns) { | |
1317 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1318 | put_user_ns(old); | |
1319 | } | |
1320 | } | |
1b5d783c AV |
1321 | } |
1322 | EXPORT_SYMBOL(would_dump); | |
1323 | ||
221af7f8 LT |
1324 | void setup_new_exec(struct linux_binprm * bprm) |
1325 | { | |
221af7f8 | 1326 | arch_pick_mmap_layout(current->mm); |
1da177e4 LT |
1327 | |
1328 | /* This is the point of no return */ | |
1da177e4 LT |
1329 | current->sas_ss_sp = current->sas_ss_size = 0; |
1330 | ||
8e96e3b7 | 1331 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) |
e579d2c2 | 1332 | set_dumpable(current->mm, SUID_DUMP_USER); |
d6e71144 | 1333 | else |
6c5d5238 | 1334 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1335 | |
e041e328 | 1336 | perf_event_exec(); |
82b89778 | 1337 | __set_task_comm(current, kbasename(bprm->filename), true); |
1da177e4 | 1338 | |
0551fbd2 BH |
1339 | /* Set the new mm task size. We have to do that late because it may |
1340 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1341 | * some architectures like powerpc | |
1342 | */ | |
1343 | current->mm->task_size = TASK_SIZE; | |
1344 | ||
a6f76f23 | 1345 | /* install the new credentials */ |
8e96e3b7 EB |
1346 | if (!uid_eq(bprm->cred->uid, current_euid()) || |
1347 | !gid_eq(bprm->cred->gid, current_egid())) { | |
d2d56c5f | 1348 | current->pdeath_signal = 0; |
1b5d783c | 1349 | } else { |
1b5d783c AV |
1350 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) |
1351 | set_dumpable(current->mm, suid_dumpable); | |
1da177e4 LT |
1352 | } |
1353 | ||
1354 | /* An exec changes our domain. We are no longer part of the thread | |
1355 | group */ | |
1da177e4 | 1356 | current->self_exec_id++; |
1da177e4 | 1357 | flush_signal_handlers(current, 0); |
1da177e4 | 1358 | } |
221af7f8 | 1359 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1360 | |
a2a8474c ON |
1361 | /* |
1362 | * Prepare credentials and lock ->cred_guard_mutex. | |
1363 | * install_exec_creds() commits the new creds and drops the lock. | |
1364 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1365 | * and unlock. | |
1366 | */ | |
1367 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1368 | { | |
9b1bf12d | 1369 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
a2a8474c ON |
1370 | return -ERESTARTNOINTR; |
1371 | ||
1372 | bprm->cred = prepare_exec_creds(); | |
1373 | if (likely(bprm->cred)) | |
1374 | return 0; | |
1375 | ||
9b1bf12d | 1376 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1377 | return -ENOMEM; |
1378 | } | |
1379 | ||
c4ad8f98 | 1380 | static void free_bprm(struct linux_binprm *bprm) |
a2a8474c ON |
1381 | { |
1382 | free_arg_pages(bprm); | |
1383 | if (bprm->cred) { | |
9b1bf12d | 1384 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1385 | abort_creds(bprm->cred); |
1386 | } | |
63e46b95 ON |
1387 | if (bprm->file) { |
1388 | allow_write_access(bprm->file); | |
1389 | fput(bprm->file); | |
1390 | } | |
b66c5984 KC |
1391 | /* If a binfmt changed the interp, free it. */ |
1392 | if (bprm->interp != bprm->filename) | |
1393 | kfree(bprm->interp); | |
a2a8474c ON |
1394 | kfree(bprm); |
1395 | } | |
1396 | ||
b66c5984 KC |
1397 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) |
1398 | { | |
1399 | /* If a binfmt changed the interp, free it first. */ | |
1400 | if (bprm->interp != bprm->filename) | |
1401 | kfree(bprm->interp); | |
1402 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1403 | if (!bprm->interp) | |
1404 | return -ENOMEM; | |
1405 | return 0; | |
1406 | } | |
1407 | EXPORT_SYMBOL(bprm_change_interp); | |
1408 | ||
a6f76f23 DH |
1409 | /* |
1410 | * install the new credentials for this executable | |
1411 | */ | |
1412 | void install_exec_creds(struct linux_binprm *bprm) | |
1413 | { | |
1414 | security_bprm_committing_creds(bprm); | |
1415 | ||
1416 | commit_creds(bprm->cred); | |
1417 | bprm->cred = NULL; | |
2976b10f SE |
1418 | |
1419 | /* | |
1420 | * Disable monitoring for regular users | |
1421 | * when executing setuid binaries. Must | |
1422 | * wait until new credentials are committed | |
1423 | * by commit_creds() above | |
1424 | */ | |
1425 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1426 | perf_event_exit_task(current); | |
a2a8474c ON |
1427 | /* |
1428 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1429 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1430 | * credentials; any time after this it may be unlocked. |
1431 | */ | |
a6f76f23 | 1432 | security_bprm_committed_creds(bprm); |
9b1bf12d | 1433 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a6f76f23 DH |
1434 | } |
1435 | EXPORT_SYMBOL(install_exec_creds); | |
1436 | ||
1437 | /* | |
1438 | * determine how safe it is to execute the proposed program | |
9b1bf12d | 1439 | * - the caller must hold ->cred_guard_mutex to protect against |
c2e1f2e3 | 1440 | * PTRACE_ATTACH or seccomp thread-sync |
a6f76f23 | 1441 | */ |
9e00cdb0 | 1442 | static void check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1443 | { |
0bf2f3ae | 1444 | struct task_struct *p = current, *t; |
f1191b50 | 1445 | unsigned n_fs; |
5f3642a2 | 1446 | bool fs_recheck; |
a6f76f23 | 1447 | |
4b9d33e6 | 1448 | if (p->ptrace) { |
64b875f7 | 1449 | if (ptracer_capable(p, current_user_ns())) |
4b9d33e6 TH |
1450 | bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; |
1451 | else | |
1452 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
1453 | } | |
a6f76f23 | 1454 | |
259e5e6c AL |
1455 | /* |
1456 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1457 | * mess up. | |
1458 | */ | |
1d4457f9 | 1459 | if (task_no_new_privs(current)) |
259e5e6c AL |
1460 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
1461 | ||
5f3642a2 CIK |
1462 | recheck: |
1463 | fs_recheck = false; | |
83f62a2e | 1464 | t = p; |
0bf2f3ae | 1465 | n_fs = 1; |
2a4419b5 | 1466 | spin_lock(&p->fs->lock); |
437f7fdb | 1467 | rcu_read_lock(); |
83f62a2e | 1468 | while_each_thread(p, t) { |
0bf2f3ae DH |
1469 | if (t->fs == p->fs) |
1470 | n_fs++; | |
5f3642a2 CIK |
1471 | if (t->flags & (PF_EXITING | PF_FORKNOEXEC)) |
1472 | fs_recheck = true; | |
0bf2f3ae | 1473 | } |
437f7fdb | 1474 | rcu_read_unlock(); |
0bf2f3ae | 1475 | |
5f3642a2 CIK |
1476 | if (p->fs->users > n_fs) { |
1477 | if (fs_recheck) { | |
1478 | spin_unlock(&p->fs->lock); | |
1479 | goto recheck; | |
1480 | } | |
a6f76f23 | 1481 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
5f3642a2 | 1482 | } else |
9e00cdb0 | 1483 | p->fs->in_exec = 1; |
2a4419b5 | 1484 | spin_unlock(&p->fs->lock); |
a6f76f23 DH |
1485 | } |
1486 | ||
8b01fc86 JH |
1487 | static void bprm_fill_uid(struct linux_binprm *bprm) |
1488 | { | |
1489 | struct inode *inode; | |
1490 | unsigned int mode; | |
1491 | kuid_t uid; | |
1492 | kgid_t gid; | |
1493 | ||
cb6fd68f KC |
1494 | /* |
1495 | * Since this can be called multiple times (via prepare_binprm), | |
1496 | * we must clear any previous work done when setting set[ug]id | |
1497 | * bits from any earlier bprm->file uses (for example when run | |
1498 | * first for a setuid script then again for its interpreter). | |
1499 | */ | |
8b01fc86 JH |
1500 | bprm->cred->euid = current_euid(); |
1501 | bprm->cred->egid = current_egid(); | |
1502 | ||
8f060a31 | 1503 | if (path_nosuid(&bprm->file->f_path)) |
8b01fc86 JH |
1504 | return; |
1505 | ||
1506 | if (task_no_new_privs(current)) | |
1507 | return; | |
1508 | ||
1509 | inode = file_inode(bprm->file); | |
1510 | mode = READ_ONCE(inode->i_mode); | |
1511 | if (!(mode & (S_ISUID|S_ISGID))) | |
1512 | return; | |
1513 | ||
1514 | /* Be careful if suid/sgid is set */ | |
5955102c | 1515 | inode_lock(inode); |
8b01fc86 JH |
1516 | |
1517 | /* reload atomically mode/uid/gid now that lock held */ | |
1518 | mode = inode->i_mode; | |
1519 | uid = inode->i_uid; | |
1520 | gid = inode->i_gid; | |
5955102c | 1521 | inode_unlock(inode); |
8b01fc86 JH |
1522 | |
1523 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1524 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1525 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1526 | return; | |
1527 | ||
1528 | if (mode & S_ISUID) { | |
1529 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1530 | bprm->cred->euid = uid; | |
1531 | } | |
1532 | ||
1533 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1534 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1535 | bprm->cred->egid = gid; | |
1536 | } | |
1537 | } | |
1538 | ||
9e00cdb0 ON |
1539 | /* |
1540 | * Fill the binprm structure from the inode. | |
1da177e4 | 1541 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
a6f76f23 DH |
1542 | * |
1543 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1544 | */ |
1545 | int prepare_binprm(struct linux_binprm *bprm) | |
1546 | { | |
1da177e4 LT |
1547 | int retval; |
1548 | ||
8b01fc86 | 1549 | bprm_fill_uid(bprm); |
1da177e4 LT |
1550 | |
1551 | /* fill in binprm security blob */ | |
a6f76f23 | 1552 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1553 | if (retval) |
1554 | return retval; | |
a6f76f23 | 1555 | bprm->cred_prepared = 1; |
1da177e4 | 1556 | |
a6f76f23 DH |
1557 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1558 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1559 | } |
1560 | ||
1561 | EXPORT_SYMBOL(prepare_binprm); | |
1562 | ||
4fc75ff4 NP |
1563 | /* |
1564 | * Arguments are '\0' separated strings found at the location bprm->p | |
1565 | * points to; chop off the first by relocating brpm->p to right after | |
1566 | * the first '\0' encountered. | |
1567 | */ | |
b6a2fea3 | 1568 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1569 | { |
b6a2fea3 OW |
1570 | int ret = 0; |
1571 | unsigned long offset; | |
1572 | char *kaddr; | |
1573 | struct page *page; | |
4fc75ff4 | 1574 | |
b6a2fea3 OW |
1575 | if (!bprm->argc) |
1576 | return 0; | |
1da177e4 | 1577 | |
b6a2fea3 OW |
1578 | do { |
1579 | offset = bprm->p & ~PAGE_MASK; | |
1580 | page = get_arg_page(bprm, bprm->p, 0); | |
1581 | if (!page) { | |
1582 | ret = -EFAULT; | |
1583 | goto out; | |
1584 | } | |
e8e3c3d6 | 1585 | kaddr = kmap_atomic(page); |
4fc75ff4 | 1586 | |
b6a2fea3 OW |
1587 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1588 | offset++, bprm->p++) | |
1589 | ; | |
4fc75ff4 | 1590 | |
e8e3c3d6 | 1591 | kunmap_atomic(kaddr); |
b6a2fea3 | 1592 | put_arg_page(page); |
b6a2fea3 | 1593 | } while (offset == PAGE_SIZE); |
4fc75ff4 | 1594 | |
b6a2fea3 OW |
1595 | bprm->p++; |
1596 | bprm->argc--; | |
1597 | ret = 0; | |
4fc75ff4 | 1598 | |
b6a2fea3 OW |
1599 | out: |
1600 | return ret; | |
1da177e4 | 1601 | } |
1da177e4 LT |
1602 | EXPORT_SYMBOL(remove_arg_zero); |
1603 | ||
cb7b6b1c | 1604 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1da177e4 LT |
1605 | /* |
1606 | * cycle the list of binary formats handler, until one recognizes the image | |
1607 | */ | |
3c456bfc | 1608 | int search_binary_handler(struct linux_binprm *bprm) |
1da177e4 | 1609 | { |
cb7b6b1c | 1610 | bool need_retry = IS_ENABLED(CONFIG_MODULES); |
1da177e4 | 1611 | struct linux_binfmt *fmt; |
cb7b6b1c | 1612 | int retval; |
1da177e4 | 1613 | |
d7402698 | 1614 | /* This allows 4 levels of binfmt rewrites before failing hard. */ |
131b2f9f | 1615 | if (bprm->recursion_depth > 5) |
d7402698 KC |
1616 | return -ELOOP; |
1617 | ||
1da177e4 LT |
1618 | retval = security_bprm_check(bprm); |
1619 | if (retval) | |
1620 | return retval; | |
1621 | ||
1da177e4 | 1622 | retval = -ENOENT; |
cb7b6b1c ON |
1623 | retry: |
1624 | read_lock(&binfmt_lock); | |
1625 | list_for_each_entry(fmt, &formats, lh) { | |
1626 | if (!try_module_get(fmt->module)) | |
1627 | continue; | |
1628 | read_unlock(&binfmt_lock); | |
1629 | bprm->recursion_depth++; | |
1630 | retval = fmt->load_binary(bprm); | |
19d860a1 AV |
1631 | read_lock(&binfmt_lock); |
1632 | put_binfmt(fmt); | |
cb7b6b1c | 1633 | bprm->recursion_depth--; |
19d860a1 AV |
1634 | if (retval < 0 && !bprm->mm) { |
1635 | /* we got to flush_old_exec() and failed after it */ | |
1636 | read_unlock(&binfmt_lock); | |
1637 | force_sigsegv(SIGSEGV, current); | |
1638 | return retval; | |
1639 | } | |
1640 | if (retval != -ENOEXEC || !bprm->file) { | |
1641 | read_unlock(&binfmt_lock); | |
cb7b6b1c | 1642 | return retval; |
1da177e4 | 1643 | } |
1da177e4 | 1644 | } |
cb7b6b1c ON |
1645 | read_unlock(&binfmt_lock); |
1646 | ||
19d860a1 | 1647 | if (need_retry) { |
cb7b6b1c ON |
1648 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && |
1649 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1650 | return retval; | |
4e0621a0 ON |
1651 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) |
1652 | return retval; | |
cb7b6b1c ON |
1653 | need_retry = false; |
1654 | goto retry; | |
1655 | } | |
1656 | ||
1da177e4 LT |
1657 | return retval; |
1658 | } | |
1da177e4 LT |
1659 | EXPORT_SYMBOL(search_binary_handler); |
1660 | ||
5d1baf3b ON |
1661 | static int exec_binprm(struct linux_binprm *bprm) |
1662 | { | |
1663 | pid_t old_pid, old_vpid; | |
1664 | int ret; | |
1665 | ||
1666 | /* Need to fetch pid before load_binary changes it */ | |
1667 | old_pid = current->pid; | |
1668 | rcu_read_lock(); | |
1669 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1670 | rcu_read_unlock(); | |
1671 | ||
1672 | ret = search_binary_handler(bprm); | |
1673 | if (ret >= 0) { | |
3eaded86 | 1674 | audit_bprm(bprm); |
5d1baf3b ON |
1675 | trace_sched_process_exec(current, old_pid, bprm); |
1676 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
9beb266f | 1677 | proc_exec_connector(current); |
5d1baf3b ON |
1678 | } |
1679 | ||
1680 | return ret; | |
1681 | } | |
1682 | ||
1da177e4 LT |
1683 | /* |
1684 | * sys_execve() executes a new program. | |
1685 | */ | |
51f39a1f DD |
1686 | static int do_execveat_common(int fd, struct filename *filename, |
1687 | struct user_arg_ptr argv, | |
1688 | struct user_arg_ptr envp, | |
1689 | int flags) | |
1da177e4 | 1690 | { |
51f39a1f | 1691 | char *pathbuf = NULL; |
1da177e4 LT |
1692 | struct linux_binprm *bprm; |
1693 | struct file *file; | |
3b125388 | 1694 | struct files_struct *displaced; |
1da177e4 | 1695 | int retval; |
72fa5997 | 1696 | |
c4ad8f98 LT |
1697 | if (IS_ERR(filename)) |
1698 | return PTR_ERR(filename); | |
1699 | ||
72fa5997 VK |
1700 | /* |
1701 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1702 | * set*uid() to execve() because too many poorly written programs | |
1703 | * don't check setuid() return code. Here we additionally recheck | |
1704 | * whether NPROC limit is still exceeded. | |
1705 | */ | |
1706 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
bd9d43f4 | 1707 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { |
72fa5997 VK |
1708 | retval = -EAGAIN; |
1709 | goto out_ret; | |
1710 | } | |
1711 | ||
1712 | /* We're below the limit (still or again), so we don't want to make | |
1713 | * further execve() calls fail. */ | |
1714 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1da177e4 | 1715 | |
3b125388 | 1716 | retval = unshare_files(&displaced); |
fd8328be AV |
1717 | if (retval) |
1718 | goto out_ret; | |
1719 | ||
1da177e4 | 1720 | retval = -ENOMEM; |
11b0b5ab | 1721 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1722 | if (!bprm) |
fd8328be | 1723 | goto out_files; |
1da177e4 | 1724 | |
a2a8474c ON |
1725 | retval = prepare_bprm_creds(bprm); |
1726 | if (retval) | |
a6f76f23 | 1727 | goto out_free; |
498052bb | 1728 | |
9e00cdb0 | 1729 | check_unsafe_exec(bprm); |
a2a8474c | 1730 | current->in_execve = 1; |
a6f76f23 | 1731 | |
51f39a1f | 1732 | file = do_open_execat(fd, filename, flags); |
1da177e4 LT |
1733 | retval = PTR_ERR(file); |
1734 | if (IS_ERR(file)) | |
498052bb | 1735 | goto out_unmark; |
1da177e4 LT |
1736 | |
1737 | sched_exec(); | |
1738 | ||
1da177e4 | 1739 | bprm->file = file; |
51f39a1f DD |
1740 | if (fd == AT_FDCWD || filename->name[0] == '/') { |
1741 | bprm->filename = filename->name; | |
1742 | } else { | |
1743 | if (filename->name[0] == '\0') | |
1744 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1745 | else | |
1746 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1747 | fd, filename->name); | |
1748 | if (!pathbuf) { | |
1749 | retval = -ENOMEM; | |
1750 | goto out_unmark; | |
1751 | } | |
1752 | /* | |
1753 | * Record that a name derived from an O_CLOEXEC fd will be | |
1754 | * inaccessible after exec. Relies on having exclusive access to | |
1755 | * current->files (due to unshare_files above). | |
1756 | */ | |
1757 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1758 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1759 | bprm->filename = pathbuf; | |
1760 | } | |
1761 | bprm->interp = bprm->filename; | |
1da177e4 | 1762 | |
b6a2fea3 OW |
1763 | retval = bprm_mm_init(bprm); |
1764 | if (retval) | |
63e46b95 | 1765 | goto out_unmark; |
1da177e4 | 1766 | |
b6a2fea3 | 1767 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1768 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1769 | goto out; |
1da177e4 | 1770 | |
b6a2fea3 | 1771 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1772 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1773 | goto out; |
1774 | ||
1775 | retval = prepare_binprm(bprm); | |
1776 | if (retval < 0) | |
1777 | goto out; | |
1778 | ||
1779 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1780 | if (retval < 0) | |
1781 | goto out; | |
1782 | ||
1783 | bprm->exec = bprm->p; | |
1784 | retval = copy_strings(bprm->envc, envp, bprm); | |
1785 | if (retval < 0) | |
1786 | goto out; | |
1787 | ||
1788 | retval = copy_strings(bprm->argc, argv, bprm); | |
1789 | if (retval < 0) | |
1790 | goto out; | |
1791 | ||
f84df2a6 EB |
1792 | would_dump(bprm, bprm->file); |
1793 | ||
5d1baf3b | 1794 | retval = exec_binprm(bprm); |
a6f76f23 DH |
1795 | if (retval < 0) |
1796 | goto out; | |
1da177e4 | 1797 | |
a6f76f23 | 1798 | /* execve succeeded */ |
498052bb | 1799 | current->fs->in_exec = 0; |
f9ce1f1c | 1800 | current->in_execve = 0; |
a6f76f23 | 1801 | acct_update_integrals(current); |
82727018 | 1802 | task_numa_free(current); |
a6f76f23 | 1803 | free_bprm(bprm); |
51f39a1f | 1804 | kfree(pathbuf); |
c4ad8f98 | 1805 | putname(filename); |
a6f76f23 DH |
1806 | if (displaced) |
1807 | put_files_struct(displaced); | |
1808 | return retval; | |
1da177e4 | 1809 | |
a6f76f23 | 1810 | out: |
3c77f845 ON |
1811 | if (bprm->mm) { |
1812 | acct_arg_size(bprm, 0); | |
1813 | mmput(bprm->mm); | |
1814 | } | |
1da177e4 | 1815 | |
498052bb | 1816 | out_unmark: |
9e00cdb0 | 1817 | current->fs->in_exec = 0; |
f9ce1f1c | 1818 | current->in_execve = 0; |
a6f76f23 DH |
1819 | |
1820 | out_free: | |
08a6fac1 | 1821 | free_bprm(bprm); |
51f39a1f | 1822 | kfree(pathbuf); |
1da177e4 | 1823 | |
fd8328be | 1824 | out_files: |
3b125388 AV |
1825 | if (displaced) |
1826 | reset_files_struct(displaced); | |
1da177e4 | 1827 | out_ret: |
c4ad8f98 | 1828 | putname(filename); |
1da177e4 LT |
1829 | return retval; |
1830 | } | |
1831 | ||
c4ad8f98 | 1832 | int do_execve(struct filename *filename, |
ba2d0162 | 1833 | const char __user *const __user *__argv, |
da3d4c5f | 1834 | const char __user *const __user *__envp) |
ba2d0162 | 1835 | { |
0e028465 ON |
1836 | struct user_arg_ptr argv = { .ptr.native = __argv }; |
1837 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
51f39a1f DD |
1838 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1839 | } | |
1840 | ||
1841 | int do_execveat(int fd, struct filename *filename, | |
1842 | const char __user *const __user *__argv, | |
1843 | const char __user *const __user *__envp, | |
1844 | int flags) | |
1845 | { | |
1846 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1847 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1848 | ||
1849 | return do_execveat_common(fd, filename, argv, envp, flags); | |
0e028465 ON |
1850 | } |
1851 | ||
1852 | #ifdef CONFIG_COMPAT | |
c4ad8f98 | 1853 | static int compat_do_execve(struct filename *filename, |
38b983b3 | 1854 | const compat_uptr_t __user *__argv, |
d03d26e5 | 1855 | const compat_uptr_t __user *__envp) |
0e028465 ON |
1856 | { |
1857 | struct user_arg_ptr argv = { | |
1858 | .is_compat = true, | |
1859 | .ptr.compat = __argv, | |
1860 | }; | |
1861 | struct user_arg_ptr envp = { | |
1862 | .is_compat = true, | |
1863 | .ptr.compat = __envp, | |
1864 | }; | |
51f39a1f DD |
1865 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1866 | } | |
1867 | ||
1868 | static int compat_do_execveat(int fd, struct filename *filename, | |
1869 | const compat_uptr_t __user *__argv, | |
1870 | const compat_uptr_t __user *__envp, | |
1871 | int flags) | |
1872 | { | |
1873 | struct user_arg_ptr argv = { | |
1874 | .is_compat = true, | |
1875 | .ptr.compat = __argv, | |
1876 | }; | |
1877 | struct user_arg_ptr envp = { | |
1878 | .is_compat = true, | |
1879 | .ptr.compat = __envp, | |
1880 | }; | |
1881 | return do_execveat_common(fd, filename, argv, envp, flags); | |
ba2d0162 | 1882 | } |
0e028465 | 1883 | #endif |
ba2d0162 | 1884 | |
964ee7df | 1885 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1886 | { |
801460d0 HS |
1887 | struct mm_struct *mm = current->mm; |
1888 | ||
1889 | if (mm->binfmt) | |
1890 | module_put(mm->binfmt->module); | |
1da177e4 | 1891 | |
801460d0 | 1892 | mm->binfmt = new; |
964ee7df ON |
1893 | if (new) |
1894 | __module_get(new->module); | |
1da177e4 | 1895 | } |
1da177e4 LT |
1896 | EXPORT_SYMBOL(set_binfmt); |
1897 | ||
6c5d5238 | 1898 | /* |
7288e118 | 1899 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. |
6c5d5238 KH |
1900 | */ |
1901 | void set_dumpable(struct mm_struct *mm, int value) | |
1902 | { | |
abacd2fe ON |
1903 | unsigned long old, new; |
1904 | ||
7288e118 ON |
1905 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) |
1906 | return; | |
1907 | ||
abacd2fe ON |
1908 | do { |
1909 | old = ACCESS_ONCE(mm->flags); | |
7288e118 | 1910 | new = (old & ~MMF_DUMPABLE_MASK) | value; |
abacd2fe | 1911 | } while (cmpxchg(&mm->flags, old, new) != old); |
6c5d5238 | 1912 | } |
6c5d5238 | 1913 | |
38b983b3 AV |
1914 | SYSCALL_DEFINE3(execve, |
1915 | const char __user *, filename, | |
1916 | const char __user *const __user *, argv, | |
1917 | const char __user *const __user *, envp) | |
1918 | { | |
c4ad8f98 | 1919 | return do_execve(getname(filename), argv, envp); |
38b983b3 | 1920 | } |
51f39a1f DD |
1921 | |
1922 | SYSCALL_DEFINE5(execveat, | |
1923 | int, fd, const char __user *, filename, | |
1924 | const char __user *const __user *, argv, | |
1925 | const char __user *const __user *, envp, | |
1926 | int, flags) | |
1927 | { | |
1928 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1929 | ||
1930 | return do_execveat(fd, | |
1931 | getname_flags(filename, lookup_flags, NULL), | |
1932 | argv, envp, flags); | |
1933 | } | |
1934 | ||
38b983b3 | 1935 | #ifdef CONFIG_COMPAT |
625b1d7e HC |
1936 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, |
1937 | const compat_uptr_t __user *, argv, | |
1938 | const compat_uptr_t __user *, envp) | |
38b983b3 | 1939 | { |
c4ad8f98 | 1940 | return compat_do_execve(getname(filename), argv, envp); |
38b983b3 | 1941 | } |
51f39a1f DD |
1942 | |
1943 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1944 | const char __user *, filename, | |
1945 | const compat_uptr_t __user *, argv, | |
1946 | const compat_uptr_t __user *, envp, | |
1947 | int, flags) | |
1948 | { | |
1949 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1950 | ||
1951 | return compat_do_execveat(fd, | |
1952 | getname_flags(filename, lookup_flags, NULL), | |
1953 | argv, envp, flags); | |
1954 | } | |
38b983b3 | 1955 | #endif |