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 | |
22 | * formats. | |
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> |
1da177e4 LT |
29 | #include <linux/stat.h> |
30 | #include <linux/fcntl.h> | |
ba92a43d | 31 | #include <linux/swap.h> |
74aadce9 | 32 | #include <linux/string.h> |
1da177e4 | 33 | #include <linux/init.h> |
ca5b172b | 34 | #include <linux/pagemap.h> |
cdd6c482 | 35 | #include <linux/perf_event.h> |
1da177e4 LT |
36 | #include <linux/highmem.h> |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/key.h> | |
39 | #include <linux/personality.h> | |
40 | #include <linux/binfmts.h> | |
1da177e4 | 41 | #include <linux/utsname.h> |
84d73786 | 42 | #include <linux/pid_namespace.h> |
1da177e4 LT |
43 | #include <linux/module.h> |
44 | #include <linux/namei.h> | |
45 | #include <linux/proc_fs.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> |
1da177e4 LT |
58 | |
59 | #include <asm/uaccess.h> | |
60 | #include <asm/mmu_context.h> | |
b6a2fea3 | 61 | #include <asm/tlb.h> |
a6f76f23 | 62 | #include "internal.h" |
1da177e4 | 63 | |
1da177e4 | 64 | int core_uses_pid; |
71ce92f3 | 65 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
a293980c | 66 | unsigned int core_pipe_limit; |
d6e71144 AC |
67 | int suid_dumpable = 0; |
68 | ||
1b0d300b XF |
69 | struct core_name { |
70 | char *corename; | |
71 | int used, size; | |
72 | }; | |
73 | static atomic_t call_count = ATOMIC_INIT(1); | |
74 | ||
1da177e4 LT |
75 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
76 | ||
e4dc1b14 | 77 | static LIST_HEAD(formats); |
1da177e4 LT |
78 | static DEFINE_RWLOCK(binfmt_lock); |
79 | ||
74641f58 | 80 | int __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 81 | { |
1da177e4 LT |
82 | if (!fmt) |
83 | return -EINVAL; | |
1da177e4 | 84 | write_lock(&binfmt_lock); |
74641f58 IK |
85 | insert ? list_add(&fmt->lh, &formats) : |
86 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 LT |
87 | write_unlock(&binfmt_lock); |
88 | return 0; | |
89 | } | |
90 | ||
74641f58 | 91 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 92 | |
f6b450d4 | 93 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 94 | { |
1da177e4 | 95 | write_lock(&binfmt_lock); |
e4dc1b14 | 96 | list_del(&fmt->lh); |
1da177e4 | 97 | write_unlock(&binfmt_lock); |
1da177e4 LT |
98 | } |
99 | ||
100 | EXPORT_SYMBOL(unregister_binfmt); | |
101 | ||
102 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
103 | { | |
104 | module_put(fmt->module); | |
105 | } | |
106 | ||
107 | /* | |
108 | * Note that a shared library must be both readable and executable due to | |
109 | * security reasons. | |
110 | * | |
111 | * Also note that we take the address to load from from the file itself. | |
112 | */ | |
1e7bfb21 | 113 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 114 | { |
964bd183 | 115 | struct file *file; |
964bd183 AV |
116 | char *tmp = getname(library); |
117 | int error = PTR_ERR(tmp); | |
118 | ||
6e8341a1 AV |
119 | if (IS_ERR(tmp)) |
120 | goto out; | |
121 | ||
122 | file = do_filp_open(AT_FDCWD, tmp, | |
123 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
124 | MAY_READ | MAY_EXEC | MAY_OPEN); | |
125 | putname(tmp); | |
126 | error = PTR_ERR(file); | |
127 | if (IS_ERR(file)) | |
1da177e4 LT |
128 | goto out; |
129 | ||
130 | error = -EINVAL; | |
6e8341a1 | 131 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
1da177e4 LT |
132 | goto exit; |
133 | ||
30524472 | 134 | error = -EACCES; |
6e8341a1 | 135 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
1da177e4 LT |
136 | goto exit; |
137 | ||
2a12a9d7 | 138 | fsnotify_open(file); |
6110e3ab | 139 | |
1da177e4 LT |
140 | error = -ENOEXEC; |
141 | if(file->f_op) { | |
142 | struct linux_binfmt * fmt; | |
143 | ||
144 | read_lock(&binfmt_lock); | |
e4dc1b14 | 145 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
146 | if (!fmt->load_shlib) |
147 | continue; | |
148 | if (!try_module_get(fmt->module)) | |
149 | continue; | |
150 | read_unlock(&binfmt_lock); | |
151 | error = fmt->load_shlib(file); | |
152 | read_lock(&binfmt_lock); | |
153 | put_binfmt(fmt); | |
154 | if (error != -ENOEXEC) | |
155 | break; | |
156 | } | |
157 | read_unlock(&binfmt_lock); | |
158 | } | |
6e8341a1 | 159 | exit: |
1da177e4 LT |
160 | fput(file); |
161 | out: | |
162 | return error; | |
1da177e4 LT |
163 | } |
164 | ||
b6a2fea3 OW |
165 | #ifdef CONFIG_MMU |
166 | ||
3c77f845 ON |
167 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
168 | { | |
169 | struct mm_struct *mm = current->mm; | |
170 | long diff = (long)(pages - bprm->vma_pages); | |
171 | ||
172 | if (!mm || !diff) | |
173 | return; | |
174 | ||
175 | bprm->vma_pages = pages; | |
176 | ||
177 | #ifdef SPLIT_RSS_COUNTING | |
178 | add_mm_counter(mm, MM_ANONPAGES, diff); | |
179 | #else | |
180 | spin_lock(&mm->page_table_lock); | |
181 | add_mm_counter(mm, MM_ANONPAGES, diff); | |
182 | spin_unlock(&mm->page_table_lock); | |
183 | #endif | |
184 | } | |
185 | ||
b6a2fea3 OW |
186 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
187 | int write) | |
188 | { | |
189 | struct page *page; | |
190 | int ret; | |
191 | ||
192 | #ifdef CONFIG_STACK_GROWSUP | |
193 | if (write) { | |
194 | ret = expand_stack_downwards(bprm->vma, pos); | |
195 | if (ret < 0) | |
196 | return NULL; | |
197 | } | |
198 | #endif | |
199 | ret = get_user_pages(current, bprm->mm, pos, | |
200 | 1, write, 1, &page, NULL); | |
201 | if (ret <= 0) | |
202 | return NULL; | |
203 | ||
204 | if (write) { | |
b6a2fea3 | 205 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
206 | struct rlimit *rlim; |
207 | ||
3c77f845 ON |
208 | acct_arg_size(bprm, size / PAGE_SIZE); |
209 | ||
a64e715f LT |
210 | /* |
211 | * We've historically supported up to 32 pages (ARG_MAX) | |
212 | * of argument strings even with small stacks | |
213 | */ | |
214 | if (size <= ARG_MAX) | |
215 | return page; | |
b6a2fea3 OW |
216 | |
217 | /* | |
218 | * Limit to 1/4-th the stack size for the argv+env strings. | |
219 | * This ensures that: | |
220 | * - the remaining binfmt code will not run out of stack space, | |
221 | * - the program will have a reasonable amount of stack left | |
222 | * to work from. | |
223 | */ | |
a64e715f | 224 | rlim = current->signal->rlim; |
d554ed89 | 225 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
b6a2fea3 OW |
226 | put_page(page); |
227 | return NULL; | |
228 | } | |
229 | } | |
230 | ||
231 | return page; | |
232 | } | |
233 | ||
234 | static void put_arg_page(struct page *page) | |
235 | { | |
236 | put_page(page); | |
237 | } | |
238 | ||
239 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
240 | { | |
241 | } | |
242 | ||
243 | static void free_arg_pages(struct linux_binprm *bprm) | |
244 | { | |
245 | } | |
246 | ||
247 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
248 | struct page *page) | |
249 | { | |
250 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
251 | } | |
252 | ||
253 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
254 | { | |
eaccbfa5 | 255 | int err; |
b6a2fea3 OW |
256 | struct vm_area_struct *vma = NULL; |
257 | struct mm_struct *mm = bprm->mm; | |
258 | ||
259 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
260 | if (!vma) | |
eaccbfa5 | 261 | return -ENOMEM; |
b6a2fea3 OW |
262 | |
263 | down_write(&mm->mmap_sem); | |
264 | vma->vm_mm = mm; | |
265 | ||
266 | /* | |
267 | * Place the stack at the largest stack address the architecture | |
268 | * supports. Later, we'll move this to an appropriate place. We don't | |
269 | * use STACK_TOP because that can depend on attributes which aren't | |
270 | * configured yet. | |
271 | */ | |
a8bef8ff | 272 | BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
273 | vma->vm_end = STACK_TOP_MAX; |
274 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
a8bef8ff | 275 | vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 276 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
5beb4930 | 277 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
b6a2fea3 | 278 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 279 | if (err) |
b6a2fea3 | 280 | goto err; |
b6a2fea3 OW |
281 | |
282 | mm->stack_vm = mm->total_vm = 1; | |
283 | up_write(&mm->mmap_sem); | |
b6a2fea3 | 284 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 285 | return 0; |
b6a2fea3 | 286 | err: |
eaccbfa5 LFC |
287 | up_write(&mm->mmap_sem); |
288 | bprm->vma = NULL; | |
289 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
290 | return err; |
291 | } | |
292 | ||
293 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
294 | { | |
295 | return len <= MAX_ARG_STRLEN; | |
296 | } | |
297 | ||
298 | #else | |
299 | ||
3c77f845 ON |
300 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
301 | { | |
302 | } | |
303 | ||
b6a2fea3 OW |
304 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
305 | int write) | |
306 | { | |
307 | struct page *page; | |
308 | ||
309 | page = bprm->page[pos / PAGE_SIZE]; | |
310 | if (!page && write) { | |
311 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
312 | if (!page) | |
313 | return NULL; | |
314 | bprm->page[pos / PAGE_SIZE] = page; | |
315 | } | |
316 | ||
317 | return page; | |
318 | } | |
319 | ||
320 | static void put_arg_page(struct page *page) | |
321 | { | |
322 | } | |
323 | ||
324 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
325 | { | |
326 | if (bprm->page[i]) { | |
327 | __free_page(bprm->page[i]); | |
328 | bprm->page[i] = NULL; | |
329 | } | |
330 | } | |
331 | ||
332 | static void free_arg_pages(struct linux_binprm *bprm) | |
333 | { | |
334 | int i; | |
335 | ||
336 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
337 | free_arg_page(bprm, i); | |
338 | } | |
339 | ||
340 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
341 | struct page *page) | |
342 | { | |
343 | } | |
344 | ||
345 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
346 | { | |
347 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
348 | return 0; | |
349 | } | |
350 | ||
351 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
352 | { | |
353 | return len <= bprm->p; | |
354 | } | |
355 | ||
356 | #endif /* CONFIG_MMU */ | |
357 | ||
358 | /* | |
359 | * Create a new mm_struct and populate it with a temporary stack | |
360 | * vm_area_struct. We don't have enough context at this point to set the stack | |
361 | * flags, permissions, and offset, so we use temporary values. We'll update | |
362 | * them later in setup_arg_pages(). | |
363 | */ | |
364 | int bprm_mm_init(struct linux_binprm *bprm) | |
365 | { | |
366 | int err; | |
367 | struct mm_struct *mm = NULL; | |
368 | ||
369 | bprm->mm = mm = mm_alloc(); | |
370 | err = -ENOMEM; | |
371 | if (!mm) | |
372 | goto err; | |
373 | ||
374 | err = init_new_context(current, mm); | |
375 | if (err) | |
376 | goto err; | |
377 | ||
378 | err = __bprm_mm_init(bprm); | |
379 | if (err) | |
380 | goto err; | |
381 | ||
382 | return 0; | |
383 | ||
384 | err: | |
385 | if (mm) { | |
386 | bprm->mm = NULL; | |
387 | mmdrop(mm); | |
388 | } | |
389 | ||
390 | return err; | |
391 | } | |
392 | ||
1da177e4 LT |
393 | /* |
394 | * count() counts the number of strings in array ARGV. | |
395 | */ | |
d7627467 | 396 | static int count(const char __user * const __user * argv, int max) |
1da177e4 LT |
397 | { |
398 | int i = 0; | |
399 | ||
400 | if (argv != NULL) { | |
401 | for (;;) { | |
d7627467 | 402 | const char __user * p; |
1da177e4 LT |
403 | |
404 | if (get_user(p, argv)) | |
405 | return -EFAULT; | |
406 | if (!p) | |
407 | break; | |
408 | argv++; | |
362e6663 | 409 | if (i++ >= max) |
1da177e4 | 410 | return -E2BIG; |
9aea5a65 RM |
411 | |
412 | if (fatal_signal_pending(current)) | |
413 | return -ERESTARTNOHAND; | |
1da177e4 LT |
414 | cond_resched(); |
415 | } | |
416 | } | |
417 | return i; | |
418 | } | |
419 | ||
420 | /* | |
b6a2fea3 OW |
421 | * 'copy_strings()' copies argument/environment strings from the old |
422 | * processes's memory to the new process's stack. The call to get_user_pages() | |
423 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 424 | */ |
d7627467 | 425 | static int copy_strings(int argc, const char __user *const __user *argv, |
75c96f85 | 426 | struct linux_binprm *bprm) |
1da177e4 LT |
427 | { |
428 | struct page *kmapped_page = NULL; | |
429 | char *kaddr = NULL; | |
b6a2fea3 | 430 | unsigned long kpos = 0; |
1da177e4 LT |
431 | int ret; |
432 | ||
433 | while (argc-- > 0) { | |
d7627467 | 434 | const char __user *str; |
1da177e4 LT |
435 | int len; |
436 | unsigned long pos; | |
437 | ||
438 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 439 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
440 | ret = -EFAULT; |
441 | goto out; | |
442 | } | |
443 | ||
b6a2fea3 | 444 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
445 | ret = -E2BIG; |
446 | goto out; | |
447 | } | |
448 | ||
b6a2fea3 | 449 | /* We're going to work our way backwords. */ |
1da177e4 | 450 | pos = bprm->p; |
b6a2fea3 OW |
451 | str += len; |
452 | bprm->p -= len; | |
1da177e4 LT |
453 | |
454 | while (len > 0) { | |
1da177e4 | 455 | int offset, bytes_to_copy; |
1da177e4 | 456 | |
9aea5a65 RM |
457 | if (fatal_signal_pending(current)) { |
458 | ret = -ERESTARTNOHAND; | |
459 | goto out; | |
460 | } | |
7993bc1f RM |
461 | cond_resched(); |
462 | ||
1da177e4 | 463 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
464 | if (offset == 0) |
465 | offset = PAGE_SIZE; | |
466 | ||
467 | bytes_to_copy = offset; | |
468 | if (bytes_to_copy > len) | |
469 | bytes_to_copy = len; | |
470 | ||
471 | offset -= bytes_to_copy; | |
472 | pos -= bytes_to_copy; | |
473 | str -= bytes_to_copy; | |
474 | len -= bytes_to_copy; | |
475 | ||
476 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
477 | struct page *page; | |
478 | ||
479 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 480 | if (!page) { |
b6a2fea3 | 481 | ret = -E2BIG; |
1da177e4 LT |
482 | goto out; |
483 | } | |
1da177e4 | 484 | |
b6a2fea3 OW |
485 | if (kmapped_page) { |
486 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 487 | kunmap(kmapped_page); |
b6a2fea3 OW |
488 | put_arg_page(kmapped_page); |
489 | } | |
1da177e4 LT |
490 | kmapped_page = page; |
491 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
492 | kpos = pos & PAGE_MASK; |
493 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 494 | } |
b6a2fea3 | 495 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
496 | ret = -EFAULT; |
497 | goto out; | |
498 | } | |
1da177e4 LT |
499 | } |
500 | } | |
501 | ret = 0; | |
502 | out: | |
b6a2fea3 OW |
503 | if (kmapped_page) { |
504 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 505 | kunmap(kmapped_page); |
b6a2fea3 OW |
506 | put_arg_page(kmapped_page); |
507 | } | |
1da177e4 LT |
508 | return ret; |
509 | } | |
510 | ||
511 | /* | |
512 | * Like copy_strings, but get argv and its values from kernel memory. | |
513 | */ | |
d7627467 DH |
514 | int copy_strings_kernel(int argc, const char *const *argv, |
515 | struct linux_binprm *bprm) | |
1da177e4 LT |
516 | { |
517 | int r; | |
518 | mm_segment_t oldfs = get_fs(); | |
519 | set_fs(KERNEL_DS); | |
d7627467 | 520 | r = copy_strings(argc, (const char __user *const __user *)argv, bprm); |
1da177e4 LT |
521 | set_fs(oldfs); |
522 | return r; | |
523 | } | |
1da177e4 LT |
524 | EXPORT_SYMBOL(copy_strings_kernel); |
525 | ||
526 | #ifdef CONFIG_MMU | |
b6a2fea3 | 527 | |
1da177e4 | 528 | /* |
b6a2fea3 OW |
529 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
530 | * the binfmt code determines where the new stack should reside, we shift it to | |
531 | * its final location. The process proceeds as follows: | |
1da177e4 | 532 | * |
b6a2fea3 OW |
533 | * 1) Use shift to calculate the new vma endpoints. |
534 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
535 | * arguments passed to subsequent functions are consistent. | |
536 | * 3) Move vma's page tables to the new range. | |
537 | * 4) Free up any cleared pgd range. | |
538 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 539 | */ |
b6a2fea3 | 540 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
541 | { |
542 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
543 | unsigned long old_start = vma->vm_start; |
544 | unsigned long old_end = vma->vm_end; | |
545 | unsigned long length = old_end - old_start; | |
546 | unsigned long new_start = old_start - shift; | |
547 | unsigned long new_end = old_end - shift; | |
548 | struct mmu_gather *tlb; | |
1da177e4 | 549 | |
b6a2fea3 | 550 | BUG_ON(new_start > new_end); |
1da177e4 | 551 | |
b6a2fea3 OW |
552 | /* |
553 | * ensure there are no vmas between where we want to go | |
554 | * and where we are | |
555 | */ | |
556 | if (vma != find_vma(mm, new_start)) | |
557 | return -EFAULT; | |
558 | ||
559 | /* | |
560 | * cover the whole range: [new_start, old_end) | |
561 | */ | |
5beb4930 RR |
562 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
563 | return -ENOMEM; | |
b6a2fea3 OW |
564 | |
565 | /* | |
566 | * move the page tables downwards, on failure we rely on | |
567 | * process cleanup to remove whatever mess we made. | |
568 | */ | |
569 | if (length != move_page_tables(vma, old_start, | |
570 | vma, new_start, length)) | |
571 | return -ENOMEM; | |
572 | ||
573 | lru_add_drain(); | |
574 | tlb = tlb_gather_mmu(mm, 0); | |
575 | if (new_end > old_start) { | |
576 | /* | |
577 | * when the old and new regions overlap clear from new_end. | |
578 | */ | |
42b77728 | 579 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
580 | vma->vm_next ? vma->vm_next->vm_start : 0); |
581 | } else { | |
582 | /* | |
583 | * otherwise, clean from old_start; this is done to not touch | |
584 | * the address space in [new_end, old_start) some architectures | |
585 | * have constraints on va-space that make this illegal (IA64) - | |
586 | * for the others its just a little faster. | |
587 | */ | |
42b77728 | 588 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 589 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 590 | } |
b6a2fea3 OW |
591 | tlb_finish_mmu(tlb, new_end, old_end); |
592 | ||
593 | /* | |
5beb4930 | 594 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
595 | */ |
596 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
597 | ||
598 | return 0; | |
1da177e4 LT |
599 | } |
600 | ||
b6a2fea3 OW |
601 | /* |
602 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
603 | * the stack is optionally relocated, and some extra space is added. | |
604 | */ | |
1da177e4 LT |
605 | int setup_arg_pages(struct linux_binprm *bprm, |
606 | unsigned long stack_top, | |
607 | int executable_stack) | |
608 | { | |
b6a2fea3 OW |
609 | unsigned long ret; |
610 | unsigned long stack_shift; | |
1da177e4 | 611 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
612 | struct vm_area_struct *vma = bprm->vma; |
613 | struct vm_area_struct *prev = NULL; | |
614 | unsigned long vm_flags; | |
615 | unsigned long stack_base; | |
803bf5ec MN |
616 | unsigned long stack_size; |
617 | unsigned long stack_expand; | |
618 | unsigned long rlim_stack; | |
1da177e4 LT |
619 | |
620 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 | 621 | /* Limit stack size to 1GB */ |
d554ed89 | 622 | stack_base = rlimit_max(RLIMIT_STACK); |
1da177e4 LT |
623 | if (stack_base > (1 << 30)) |
624 | stack_base = 1 << 30; | |
1da177e4 | 625 | |
b6a2fea3 OW |
626 | /* Make sure we didn't let the argument array grow too large. */ |
627 | if (vma->vm_end - vma->vm_start > stack_base) | |
628 | return -ENOMEM; | |
1da177e4 | 629 | |
b6a2fea3 | 630 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 631 | |
b6a2fea3 OW |
632 | stack_shift = vma->vm_start - stack_base; |
633 | mm->arg_start = bprm->p - stack_shift; | |
634 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 635 | #else |
b6a2fea3 OW |
636 | stack_top = arch_align_stack(stack_top); |
637 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
638 | |
639 | if (unlikely(stack_top < mmap_min_addr) || | |
640 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
641 | return -ENOMEM; | |
642 | ||
b6a2fea3 OW |
643 | stack_shift = vma->vm_end - stack_top; |
644 | ||
645 | bprm->p -= stack_shift; | |
1da177e4 | 646 | mm->arg_start = bprm->p; |
1da177e4 LT |
647 | #endif |
648 | ||
1da177e4 | 649 | if (bprm->loader) |
b6a2fea3 OW |
650 | bprm->loader -= stack_shift; |
651 | bprm->exec -= stack_shift; | |
1da177e4 | 652 | |
1da177e4 | 653 | down_write(&mm->mmap_sem); |
96a8e13e | 654 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
655 | |
656 | /* | |
657 | * Adjust stack execute permissions; explicitly enable for | |
658 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
659 | * (arch default) otherwise. | |
660 | */ | |
661 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
662 | vm_flags |= VM_EXEC; | |
663 | else if (executable_stack == EXSTACK_DISABLE_X) | |
664 | vm_flags &= ~VM_EXEC; | |
665 | vm_flags |= mm->def_flags; | |
a8bef8ff | 666 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
667 | |
668 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
669 | vm_flags); | |
670 | if (ret) | |
671 | goto out_unlock; | |
672 | BUG_ON(prev != vma); | |
673 | ||
674 | /* Move stack pages down in memory. */ | |
675 | if (stack_shift) { | |
676 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
677 | if (ret) |
678 | goto out_unlock; | |
1da177e4 LT |
679 | } |
680 | ||
a8bef8ff MG |
681 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
682 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
683 | ||
5ef097dd | 684 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
685 | stack_size = vma->vm_end - vma->vm_start; |
686 | /* | |
687 | * Align this down to a page boundary as expand_stack | |
688 | * will align it up. | |
689 | */ | |
690 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
b6a2fea3 | 691 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
692 | if (stack_size + stack_expand > rlim_stack) |
693 | stack_base = vma->vm_start + rlim_stack; | |
694 | else | |
695 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 696 | #else |
803bf5ec MN |
697 | if (stack_size + stack_expand > rlim_stack) |
698 | stack_base = vma->vm_end - rlim_stack; | |
699 | else | |
700 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 701 | #endif |
3af9e859 | 702 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
703 | ret = expand_stack(vma, stack_base); |
704 | if (ret) | |
705 | ret = -EFAULT; | |
706 | ||
707 | out_unlock: | |
1da177e4 | 708 | up_write(&mm->mmap_sem); |
fc63cf23 | 709 | return ret; |
1da177e4 | 710 | } |
1da177e4 LT |
711 | EXPORT_SYMBOL(setup_arg_pages); |
712 | ||
1da177e4 LT |
713 | #endif /* CONFIG_MMU */ |
714 | ||
715 | struct file *open_exec(const char *name) | |
716 | { | |
1da177e4 | 717 | struct file *file; |
e56b6a5d | 718 | int err; |
1da177e4 | 719 | |
6e8341a1 AV |
720 | file = do_filp_open(AT_FDCWD, name, |
721 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
722 | MAY_EXEC | MAY_OPEN); | |
723 | if (IS_ERR(file)) | |
e56b6a5d CH |
724 | goto out; |
725 | ||
726 | err = -EACCES; | |
6e8341a1 AV |
727 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
728 | goto exit; | |
e56b6a5d | 729 | |
6e8341a1 AV |
730 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
731 | goto exit; | |
e56b6a5d | 732 | |
2a12a9d7 | 733 | fsnotify_open(file); |
6110e3ab | 734 | |
e56b6a5d | 735 | err = deny_write_access(file); |
6e8341a1 AV |
736 | if (err) |
737 | goto exit; | |
1da177e4 | 738 | |
6e8341a1 | 739 | out: |
e56b6a5d CH |
740 | return file; |
741 | ||
6e8341a1 AV |
742 | exit: |
743 | fput(file); | |
e56b6a5d CH |
744 | return ERR_PTR(err); |
745 | } | |
1da177e4 LT |
746 | EXPORT_SYMBOL(open_exec); |
747 | ||
6777d773 MZ |
748 | int kernel_read(struct file *file, loff_t offset, |
749 | char *addr, unsigned long count) | |
1da177e4 LT |
750 | { |
751 | mm_segment_t old_fs; | |
752 | loff_t pos = offset; | |
753 | int result; | |
754 | ||
755 | old_fs = get_fs(); | |
756 | set_fs(get_ds()); | |
757 | /* The cast to a user pointer is valid due to the set_fs() */ | |
758 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
759 | set_fs(old_fs); | |
760 | return result; | |
761 | } | |
762 | ||
763 | EXPORT_SYMBOL(kernel_read); | |
764 | ||
765 | static int exec_mmap(struct mm_struct *mm) | |
766 | { | |
767 | struct task_struct *tsk; | |
768 | struct mm_struct * old_mm, *active_mm; | |
769 | ||
770 | /* Notify parent that we're no longer interested in the old VM */ | |
771 | tsk = current; | |
772 | old_mm = current->mm; | |
34e55232 | 773 | sync_mm_rss(tsk, old_mm); |
1da177e4 LT |
774 | mm_release(tsk, old_mm); |
775 | ||
776 | if (old_mm) { | |
777 | /* | |
778 | * Make sure that if there is a core dump in progress | |
779 | * for the old mm, we get out and die instead of going | |
780 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 781 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
782 | */ |
783 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 784 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
785 | up_read(&old_mm->mmap_sem); |
786 | return -EINTR; | |
787 | } | |
788 | } | |
789 | task_lock(tsk); | |
790 | active_mm = tsk->active_mm; | |
791 | tsk->mm = mm; | |
792 | tsk->active_mm = mm; | |
793 | activate_mm(active_mm, mm); | |
3d5992d2 YH |
794 | if (old_mm && tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { |
795 | atomic_dec(&old_mm->oom_disable_count); | |
796 | atomic_inc(&tsk->mm->oom_disable_count); | |
797 | } | |
1da177e4 LT |
798 | task_unlock(tsk); |
799 | arch_pick_mmap_layout(mm); | |
800 | if (old_mm) { | |
801 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 802 | BUG_ON(active_mm != old_mm); |
31a78f23 | 803 | mm_update_next_owner(old_mm); |
1da177e4 LT |
804 | mmput(old_mm); |
805 | return 0; | |
806 | } | |
807 | mmdrop(active_mm); | |
808 | return 0; | |
809 | } | |
810 | ||
811 | /* | |
812 | * This function makes sure the current process has its own signal table, | |
813 | * so that flush_signal_handlers can later reset the handlers without | |
814 | * disturbing other processes. (Other processes might share the signal | |
815 | * table via the CLONE_SIGHAND option to clone().) | |
816 | */ | |
858119e1 | 817 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
818 | { |
819 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 820 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 821 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 822 | |
aafe6c2a | 823 | if (thread_group_empty(tsk)) |
1da177e4 LT |
824 | goto no_thread_group; |
825 | ||
826 | /* | |
827 | * Kill all other threads in the thread group. | |
1da177e4 | 828 | */ |
1da177e4 | 829 | spin_lock_irq(lock); |
ed5d2cac | 830 | if (signal_group_exit(sig)) { |
1da177e4 LT |
831 | /* |
832 | * Another group action in progress, just | |
833 | * return so that the signal is processed. | |
834 | */ | |
835 | spin_unlock_irq(lock); | |
1da177e4 LT |
836 | return -EAGAIN; |
837 | } | |
d344193a | 838 | |
ed5d2cac | 839 | sig->group_exit_task = tsk; |
d344193a ON |
840 | sig->notify_count = zap_other_threads(tsk); |
841 | if (!thread_group_leader(tsk)) | |
842 | sig->notify_count--; | |
1da177e4 | 843 | |
d344193a | 844 | while (sig->notify_count) { |
1da177e4 LT |
845 | __set_current_state(TASK_UNINTERRUPTIBLE); |
846 | spin_unlock_irq(lock); | |
847 | schedule(); | |
848 | spin_lock_irq(lock); | |
849 | } | |
1da177e4 LT |
850 | spin_unlock_irq(lock); |
851 | ||
852 | /* | |
853 | * At this point all other threads have exited, all we have to | |
854 | * do is to wait for the thread group leader to become inactive, | |
855 | * and to assume its PID: | |
856 | */ | |
aafe6c2a | 857 | if (!thread_group_leader(tsk)) { |
8187926b | 858 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 859 | |
2800d8d1 | 860 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
861 | for (;;) { |
862 | write_lock_irq(&tasklist_lock); | |
863 | if (likely(leader->exit_state)) | |
864 | break; | |
865 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
866 | write_unlock_irq(&tasklist_lock); | |
867 | schedule(); | |
868 | } | |
1da177e4 | 869 | |
f5e90281 RM |
870 | /* |
871 | * The only record we have of the real-time age of a | |
872 | * process, regardless of execs it's done, is start_time. | |
873 | * All the past CPU time is accumulated in signal_struct | |
874 | * from sister threads now dead. But in this non-leader | |
875 | * exec, nothing survives from the original leader thread, | |
876 | * whose birth marks the true age of this process now. | |
877 | * When we take on its identity by switching to its PID, we | |
878 | * also take its birthdate (always earlier than our own). | |
879 | */ | |
aafe6c2a | 880 | tsk->start_time = leader->start_time; |
f5e90281 | 881 | |
bac0abd6 PE |
882 | BUG_ON(!same_thread_group(leader, tsk)); |
883 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
884 | /* |
885 | * An exec() starts a new thread group with the | |
886 | * TGID of the previous thread group. Rehash the | |
887 | * two threads with a switched PID, and release | |
888 | * the former thread group leader: | |
889 | */ | |
d73d6529 EB |
890 | |
891 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
892 | * The old leader becomes a thread of the this thread group. |
893 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
894 | * is called. Odd but simple and correct. |
895 | */ | |
aafe6c2a EB |
896 | detach_pid(tsk, PIDTYPE_PID); |
897 | tsk->pid = leader->pid; | |
3743ca05 | 898 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
899 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
900 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 901 | |
aafe6c2a | 902 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 903 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 904 | |
aafe6c2a EB |
905 | tsk->group_leader = tsk; |
906 | leader->group_leader = tsk; | |
de12a787 | 907 | |
aafe6c2a | 908 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
909 | |
910 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
911 | leader->exit_state = EXIT_DEAD; | |
1da177e4 | 912 | write_unlock_irq(&tasklist_lock); |
8187926b ON |
913 | |
914 | release_task(leader); | |
ed5d2cac | 915 | } |
1da177e4 | 916 | |
6db840fa ON |
917 | sig->group_exit_task = NULL; |
918 | sig->notify_count = 0; | |
1da177e4 LT |
919 | |
920 | no_thread_group: | |
1f10206c JP |
921 | if (current->mm) |
922 | setmax_mm_hiwater_rss(&sig->maxrss, current->mm); | |
923 | ||
1da177e4 | 924 | exit_itimers(sig); |
cbaffba1 | 925 | flush_itimer_signals(); |
329f7dba | 926 | |
b2c903b8 ON |
927 | if (atomic_read(&oldsighand->count) != 1) { |
928 | struct sighand_struct *newsighand; | |
1da177e4 | 929 | /* |
b2c903b8 ON |
930 | * This ->sighand is shared with the CLONE_SIGHAND |
931 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 932 | */ |
b2c903b8 ON |
933 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
934 | if (!newsighand) | |
935 | return -ENOMEM; | |
936 | ||
1da177e4 LT |
937 | atomic_set(&newsighand->count, 1); |
938 | memcpy(newsighand->action, oldsighand->action, | |
939 | sizeof(newsighand->action)); | |
940 | ||
941 | write_lock_irq(&tasklist_lock); | |
942 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 943 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
944 | spin_unlock(&oldsighand->siglock); |
945 | write_unlock_irq(&tasklist_lock); | |
946 | ||
fba2afaa | 947 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
948 | } |
949 | ||
aafe6c2a | 950 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
951 | return 0; |
952 | } | |
0840a90d | 953 | |
1da177e4 LT |
954 | /* |
955 | * These functions flushes out all traces of the currently running executable | |
956 | * so that a new one can be started | |
957 | */ | |
858119e1 | 958 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
959 | { |
960 | long j = -1; | |
badf1662 | 961 | struct fdtable *fdt; |
1da177e4 LT |
962 | |
963 | spin_lock(&files->file_lock); | |
964 | for (;;) { | |
965 | unsigned long set, i; | |
966 | ||
967 | j++; | |
968 | i = j * __NFDBITS; | |
badf1662 | 969 | fdt = files_fdtable(files); |
bbea9f69 | 970 | if (i >= fdt->max_fds) |
1da177e4 | 971 | break; |
badf1662 | 972 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
973 | if (!set) |
974 | continue; | |
badf1662 | 975 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
976 | spin_unlock(&files->file_lock); |
977 | for ( ; set ; i++,set >>= 1) { | |
978 | if (set & 1) { | |
979 | sys_close(i); | |
980 | } | |
981 | } | |
982 | spin_lock(&files->file_lock); | |
983 | ||
984 | } | |
985 | spin_unlock(&files->file_lock); | |
986 | } | |
987 | ||
59714d65 | 988 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
989 | { |
990 | /* buf must be at least sizeof(tsk->comm) in size */ | |
991 | task_lock(tsk); | |
992 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
993 | task_unlock(tsk); | |
59714d65 | 994 | return buf; |
1da177e4 LT |
995 | } |
996 | ||
997 | void set_task_comm(struct task_struct *tsk, char *buf) | |
998 | { | |
999 | task_lock(tsk); | |
4614a696 JS |
1000 | |
1001 | /* | |
1002 | * Threads may access current->comm without holding | |
1003 | * the task lock, so write the string carefully. | |
1004 | * Readers without a lock may see incomplete new | |
1005 | * names but are safe from non-terminating string reads. | |
1006 | */ | |
1007 | memset(tsk->comm, 0, TASK_COMM_LEN); | |
1008 | wmb(); | |
1da177e4 LT |
1009 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1010 | task_unlock(tsk); | |
cdd6c482 | 1011 | perf_event_comm(tsk); |
1da177e4 LT |
1012 | } |
1013 | ||
1014 | int flush_old_exec(struct linux_binprm * bprm) | |
1015 | { | |
221af7f8 | 1016 | int retval; |
1da177e4 LT |
1017 | |
1018 | /* | |
1019 | * Make sure we have a private signal table and that | |
1020 | * we are unassociated from the previous thread group. | |
1021 | */ | |
1022 | retval = de_thread(current); | |
1023 | if (retval) | |
1024 | goto out; | |
1025 | ||
925d1c40 MH |
1026 | set_mm_exe_file(bprm->mm, bprm->file); |
1027 | ||
1da177e4 LT |
1028 | /* |
1029 | * Release all of the old mmap stuff | |
1030 | */ | |
3c77f845 | 1031 | acct_arg_size(bprm, 0); |
1da177e4 LT |
1032 | retval = exec_mmap(bprm->mm); |
1033 | if (retval) | |
fd8328be | 1034 | goto out; |
1da177e4 LT |
1035 | |
1036 | bprm->mm = NULL; /* We're using it now */ | |
7ab02af4 | 1037 | |
98391cf4 | 1038 | current->flags &= ~(PF_RANDOMIZE | PF_KTHREAD); |
7ab02af4 LT |
1039 | flush_thread(); |
1040 | current->personality &= ~bprm->per_clear; | |
1041 | ||
221af7f8 LT |
1042 | return 0; |
1043 | ||
1044 | out: | |
1045 | return retval; | |
1046 | } | |
1047 | EXPORT_SYMBOL(flush_old_exec); | |
1048 | ||
1049 | void setup_new_exec(struct linux_binprm * bprm) | |
1050 | { | |
1051 | int i, ch; | |
d7627467 | 1052 | const char *name; |
221af7f8 LT |
1053 | char tcomm[sizeof(current->comm)]; |
1054 | ||
1055 | arch_pick_mmap_layout(current->mm); | |
1da177e4 LT |
1056 | |
1057 | /* This is the point of no return */ | |
1da177e4 LT |
1058 | current->sas_ss_sp = current->sas_ss_size = 0; |
1059 | ||
da9592ed | 1060 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
6c5d5238 | 1061 | set_dumpable(current->mm, 1); |
d6e71144 | 1062 | else |
6c5d5238 | 1063 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1064 | |
1da177e4 | 1065 | name = bprm->filename; |
36772092 PBG |
1066 | |
1067 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
1068 | for (i=0; (ch = *(name++)) != '\0';) { |
1069 | if (ch == '/') | |
36772092 | 1070 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
1071 | else |
1072 | if (i < (sizeof(tcomm) - 1)) | |
1073 | tcomm[i++] = ch; | |
1074 | } | |
1075 | tcomm[i] = '\0'; | |
1076 | set_task_comm(current, tcomm); | |
1077 | ||
0551fbd2 BH |
1078 | /* Set the new mm task size. We have to do that late because it may |
1079 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1080 | * some architectures like powerpc | |
1081 | */ | |
1082 | current->mm->task_size = TASK_SIZE; | |
1083 | ||
a6f76f23 DH |
1084 | /* install the new credentials */ |
1085 | if (bprm->cred->uid != current_euid() || | |
1086 | bprm->cred->gid != current_egid()) { | |
d2d56c5f MH |
1087 | current->pdeath_signal = 0; |
1088 | } else if (file_permission(bprm->file, MAY_READ) || | |
a6f76f23 | 1089 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
6c5d5238 | 1090 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1091 | } |
1092 | ||
f65cb45c IM |
1093 | /* |
1094 | * Flush performance counters when crossing a | |
1095 | * security domain: | |
1096 | */ | |
1097 | if (!get_dumpable(current->mm)) | |
cdd6c482 | 1098 | perf_event_exit_task(current); |
f65cb45c | 1099 | |
1da177e4 LT |
1100 | /* An exec changes our domain. We are no longer part of the thread |
1101 | group */ | |
1102 | ||
1103 | current->self_exec_id++; | |
1104 | ||
1105 | flush_signal_handlers(current, 0); | |
1106 | flush_old_files(current->files); | |
1da177e4 | 1107 | } |
221af7f8 | 1108 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1109 | |
a2a8474c ON |
1110 | /* |
1111 | * Prepare credentials and lock ->cred_guard_mutex. | |
1112 | * install_exec_creds() commits the new creds and drops the lock. | |
1113 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1114 | * and unlock. | |
1115 | */ | |
1116 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1117 | { | |
9b1bf12d | 1118 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
a2a8474c ON |
1119 | return -ERESTARTNOINTR; |
1120 | ||
1121 | bprm->cred = prepare_exec_creds(); | |
1122 | if (likely(bprm->cred)) | |
1123 | return 0; | |
1124 | ||
9b1bf12d | 1125 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1126 | return -ENOMEM; |
1127 | } | |
1128 | ||
1129 | void free_bprm(struct linux_binprm *bprm) | |
1130 | { | |
1131 | free_arg_pages(bprm); | |
1132 | if (bprm->cred) { | |
9b1bf12d | 1133 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1134 | abort_creds(bprm->cred); |
1135 | } | |
1136 | kfree(bprm); | |
1137 | } | |
1138 | ||
a6f76f23 DH |
1139 | /* |
1140 | * install the new credentials for this executable | |
1141 | */ | |
1142 | void install_exec_creds(struct linux_binprm *bprm) | |
1143 | { | |
1144 | security_bprm_committing_creds(bprm); | |
1145 | ||
1146 | commit_creds(bprm->cred); | |
1147 | bprm->cred = NULL; | |
a2a8474c ON |
1148 | /* |
1149 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1150 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1151 | * credentials; any time after this it may be unlocked. |
1152 | */ | |
a6f76f23 | 1153 | security_bprm_committed_creds(bprm); |
9b1bf12d | 1154 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a6f76f23 DH |
1155 | } |
1156 | EXPORT_SYMBOL(install_exec_creds); | |
1157 | ||
1158 | /* | |
1159 | * determine how safe it is to execute the proposed program | |
9b1bf12d | 1160 | * - the caller must hold ->cred_guard_mutex to protect against |
a6f76f23 DH |
1161 | * PTRACE_ATTACH |
1162 | */ | |
498052bb | 1163 | int check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1164 | { |
0bf2f3ae | 1165 | struct task_struct *p = current, *t; |
f1191b50 | 1166 | unsigned n_fs; |
498052bb | 1167 | int res = 0; |
a6f76f23 DH |
1168 | |
1169 | bprm->unsafe = tracehook_unsafe_exec(p); | |
1170 | ||
0bf2f3ae | 1171 | n_fs = 1; |
2a4419b5 | 1172 | spin_lock(&p->fs->lock); |
437f7fdb | 1173 | rcu_read_lock(); |
0bf2f3ae DH |
1174 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
1175 | if (t->fs == p->fs) | |
1176 | n_fs++; | |
0bf2f3ae | 1177 | } |
437f7fdb | 1178 | rcu_read_unlock(); |
0bf2f3ae | 1179 | |
f1191b50 | 1180 | if (p->fs->users > n_fs) { |
a6f76f23 | 1181 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
498052bb | 1182 | } else { |
8c652f96 ON |
1183 | res = -EAGAIN; |
1184 | if (!p->fs->in_exec) { | |
1185 | p->fs->in_exec = 1; | |
1186 | res = 1; | |
1187 | } | |
498052bb | 1188 | } |
2a4419b5 | 1189 | spin_unlock(&p->fs->lock); |
498052bb AV |
1190 | |
1191 | return res; | |
a6f76f23 DH |
1192 | } |
1193 | ||
1da177e4 LT |
1194 | /* |
1195 | * Fill the binprm structure from the inode. | |
1196 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
a6f76f23 DH |
1197 | * |
1198 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1199 | */ |
1200 | int prepare_binprm(struct linux_binprm *bprm) | |
1201 | { | |
a6f76f23 | 1202 | umode_t mode; |
0f7fc9e4 | 1203 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1204 | int retval; |
1205 | ||
1206 | mode = inode->i_mode; | |
1da177e4 LT |
1207 | if (bprm->file->f_op == NULL) |
1208 | return -EACCES; | |
1209 | ||
a6f76f23 DH |
1210 | /* clear any previous set[ug]id data from a previous binary */ |
1211 | bprm->cred->euid = current_euid(); | |
1212 | bprm->cred->egid = current_egid(); | |
1da177e4 | 1213 | |
a6f76f23 | 1214 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1215 | /* Set-uid? */ |
1216 | if (mode & S_ISUID) { | |
a6f76f23 DH |
1217 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1218 | bprm->cred->euid = inode->i_uid; | |
1da177e4 LT |
1219 | } |
1220 | ||
1221 | /* Set-gid? */ | |
1222 | /* | |
1223 | * If setgid is set but no group execute bit then this | |
1224 | * is a candidate for mandatory locking, not a setgid | |
1225 | * executable. | |
1226 | */ | |
1227 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
a6f76f23 DH |
1228 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1229 | bprm->cred->egid = inode->i_gid; | |
1da177e4 LT |
1230 | } |
1231 | } | |
1232 | ||
1233 | /* fill in binprm security blob */ | |
a6f76f23 | 1234 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1235 | if (retval) |
1236 | return retval; | |
a6f76f23 | 1237 | bprm->cred_prepared = 1; |
1da177e4 | 1238 | |
a6f76f23 DH |
1239 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1240 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1241 | } |
1242 | ||
1243 | EXPORT_SYMBOL(prepare_binprm); | |
1244 | ||
4fc75ff4 NP |
1245 | /* |
1246 | * Arguments are '\0' separated strings found at the location bprm->p | |
1247 | * points to; chop off the first by relocating brpm->p to right after | |
1248 | * the first '\0' encountered. | |
1249 | */ | |
b6a2fea3 | 1250 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1251 | { |
b6a2fea3 OW |
1252 | int ret = 0; |
1253 | unsigned long offset; | |
1254 | char *kaddr; | |
1255 | struct page *page; | |
4fc75ff4 | 1256 | |
b6a2fea3 OW |
1257 | if (!bprm->argc) |
1258 | return 0; | |
1da177e4 | 1259 | |
b6a2fea3 OW |
1260 | do { |
1261 | offset = bprm->p & ~PAGE_MASK; | |
1262 | page = get_arg_page(bprm, bprm->p, 0); | |
1263 | if (!page) { | |
1264 | ret = -EFAULT; | |
1265 | goto out; | |
1266 | } | |
1267 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1268 | |
b6a2fea3 OW |
1269 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1270 | offset++, bprm->p++) | |
1271 | ; | |
4fc75ff4 | 1272 | |
b6a2fea3 OW |
1273 | kunmap_atomic(kaddr, KM_USER0); |
1274 | put_arg_page(page); | |
4fc75ff4 | 1275 | |
b6a2fea3 OW |
1276 | if (offset == PAGE_SIZE) |
1277 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1278 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1279 | |
b6a2fea3 OW |
1280 | bprm->p++; |
1281 | bprm->argc--; | |
1282 | ret = 0; | |
4fc75ff4 | 1283 | |
b6a2fea3 OW |
1284 | out: |
1285 | return ret; | |
1da177e4 | 1286 | } |
1da177e4 LT |
1287 | EXPORT_SYMBOL(remove_arg_zero); |
1288 | ||
1289 | /* | |
1290 | * cycle the list of binary formats handler, until one recognizes the image | |
1291 | */ | |
1292 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1293 | { | |
85f33466 | 1294 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1295 | int try,retval; |
1296 | struct linux_binfmt *fmt; | |
1da177e4 | 1297 | |
1da177e4 LT |
1298 | retval = security_bprm_check(bprm); |
1299 | if (retval) | |
1300 | return retval; | |
1301 | ||
1302 | /* kernel module loader fixup */ | |
1303 | /* so we don't try to load run modprobe in kernel space. */ | |
1304 | set_fs(USER_DS); | |
473ae30b AV |
1305 | |
1306 | retval = audit_bprm(bprm); | |
1307 | if (retval) | |
1308 | return retval; | |
1309 | ||
1da177e4 LT |
1310 | retval = -ENOENT; |
1311 | for (try=0; try<2; try++) { | |
1312 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1313 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1314 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1315 | if (!fn) | |
1316 | continue; | |
1317 | if (!try_module_get(fmt->module)) | |
1318 | continue; | |
1319 | read_unlock(&binfmt_lock); | |
1320 | retval = fn(bprm, regs); | |
85f33466 RM |
1321 | /* |
1322 | * Restore the depth counter to its starting value | |
1323 | * in this call, so we don't have to rely on every | |
1324 | * load_binary function to restore it on return. | |
1325 | */ | |
1326 | bprm->recursion_depth = depth; | |
1da177e4 | 1327 | if (retval >= 0) { |
85f33466 RM |
1328 | if (depth == 0) |
1329 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1330 | put_binfmt(fmt); |
1331 | allow_write_access(bprm->file); | |
1332 | if (bprm->file) | |
1333 | fput(bprm->file); | |
1334 | bprm->file = NULL; | |
1335 | current->did_exec = 1; | |
9f46080c | 1336 | proc_exec_connector(current); |
1da177e4 LT |
1337 | return retval; |
1338 | } | |
1339 | read_lock(&binfmt_lock); | |
1340 | put_binfmt(fmt); | |
1341 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1342 | break; | |
1343 | if (!bprm->file) { | |
1344 | read_unlock(&binfmt_lock); | |
1345 | return retval; | |
1346 | } | |
1347 | } | |
1348 | read_unlock(&binfmt_lock); | |
1349 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1350 | break; | |
5f4123be JB |
1351 | #ifdef CONFIG_MODULES |
1352 | } else { | |
1da177e4 LT |
1353 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1354 | if (printable(bprm->buf[0]) && | |
1355 | printable(bprm->buf[1]) && | |
1356 | printable(bprm->buf[2]) && | |
1357 | printable(bprm->buf[3])) | |
1358 | break; /* -ENOEXEC */ | |
1359 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1360 | #endif | |
1361 | } | |
1362 | } | |
1363 | return retval; | |
1364 | } | |
1365 | ||
1366 | EXPORT_SYMBOL(search_binary_handler); | |
1367 | ||
1368 | /* | |
1369 | * sys_execve() executes a new program. | |
1370 | */ | |
d7627467 DH |
1371 | int do_execve(const char * filename, |
1372 | const char __user *const __user *argv, | |
1373 | const char __user *const __user *envp, | |
1da177e4 LT |
1374 | struct pt_regs * regs) |
1375 | { | |
1376 | struct linux_binprm *bprm; | |
1377 | struct file *file; | |
3b125388 | 1378 | struct files_struct *displaced; |
8c652f96 | 1379 | bool clear_in_exec; |
1da177e4 | 1380 | int retval; |
1da177e4 | 1381 | |
3b125388 | 1382 | retval = unshare_files(&displaced); |
fd8328be AV |
1383 | if (retval) |
1384 | goto out_ret; | |
1385 | ||
1da177e4 | 1386 | retval = -ENOMEM; |
11b0b5ab | 1387 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1388 | if (!bprm) |
fd8328be | 1389 | goto out_files; |
1da177e4 | 1390 | |
a2a8474c ON |
1391 | retval = prepare_bprm_creds(bprm); |
1392 | if (retval) | |
a6f76f23 | 1393 | goto out_free; |
498052bb AV |
1394 | |
1395 | retval = check_unsafe_exec(bprm); | |
8c652f96 | 1396 | if (retval < 0) |
a2a8474c | 1397 | goto out_free; |
8c652f96 | 1398 | clear_in_exec = retval; |
a2a8474c | 1399 | current->in_execve = 1; |
a6f76f23 | 1400 | |
1da177e4 LT |
1401 | file = open_exec(filename); |
1402 | retval = PTR_ERR(file); | |
1403 | if (IS_ERR(file)) | |
498052bb | 1404 | goto out_unmark; |
1da177e4 LT |
1405 | |
1406 | sched_exec(); | |
1407 | ||
1da177e4 LT |
1408 | bprm->file = file; |
1409 | bprm->filename = filename; | |
1410 | bprm->interp = filename; | |
1da177e4 | 1411 | |
b6a2fea3 OW |
1412 | retval = bprm_mm_init(bprm); |
1413 | if (retval) | |
1414 | goto out_file; | |
1da177e4 | 1415 | |
b6a2fea3 | 1416 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1417 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1418 | goto out; |
1da177e4 | 1419 | |
b6a2fea3 | 1420 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1421 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1422 | goto out; |
1423 | ||
1424 | retval = prepare_binprm(bprm); | |
1425 | if (retval < 0) | |
1426 | goto out; | |
1427 | ||
1428 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1429 | if (retval < 0) | |
1430 | goto out; | |
1431 | ||
1432 | bprm->exec = bprm->p; | |
1433 | retval = copy_strings(bprm->envc, envp, bprm); | |
1434 | if (retval < 0) | |
1435 | goto out; | |
1436 | ||
1437 | retval = copy_strings(bprm->argc, argv, bprm); | |
1438 | if (retval < 0) | |
1439 | goto out; | |
1440 | ||
1441 | retval = search_binary_handler(bprm,regs); | |
a6f76f23 DH |
1442 | if (retval < 0) |
1443 | goto out; | |
1da177e4 | 1444 | |
a6f76f23 | 1445 | /* execve succeeded */ |
498052bb | 1446 | current->fs->in_exec = 0; |
f9ce1f1c | 1447 | current->in_execve = 0; |
a6f76f23 DH |
1448 | acct_update_integrals(current); |
1449 | free_bprm(bprm); | |
1450 | if (displaced) | |
1451 | put_files_struct(displaced); | |
1452 | return retval; | |
1da177e4 | 1453 | |
a6f76f23 | 1454 | out: |
3c77f845 ON |
1455 | if (bprm->mm) { |
1456 | acct_arg_size(bprm, 0); | |
1457 | mmput(bprm->mm); | |
1458 | } | |
1da177e4 LT |
1459 | |
1460 | out_file: | |
1461 | if (bprm->file) { | |
1462 | allow_write_access(bprm->file); | |
1463 | fput(bprm->file); | |
1464 | } | |
a6f76f23 | 1465 | |
498052bb | 1466 | out_unmark: |
8c652f96 ON |
1467 | if (clear_in_exec) |
1468 | current->fs->in_exec = 0; | |
f9ce1f1c | 1469 | current->in_execve = 0; |
a6f76f23 DH |
1470 | |
1471 | out_free: | |
08a6fac1 | 1472 | free_bprm(bprm); |
1da177e4 | 1473 | |
fd8328be | 1474 | out_files: |
3b125388 AV |
1475 | if (displaced) |
1476 | reset_files_struct(displaced); | |
1da177e4 LT |
1477 | out_ret: |
1478 | return retval; | |
1479 | } | |
1480 | ||
964ee7df | 1481 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1482 | { |
801460d0 HS |
1483 | struct mm_struct *mm = current->mm; |
1484 | ||
1485 | if (mm->binfmt) | |
1486 | module_put(mm->binfmt->module); | |
1da177e4 | 1487 | |
801460d0 | 1488 | mm->binfmt = new; |
964ee7df ON |
1489 | if (new) |
1490 | __module_get(new->module); | |
1da177e4 LT |
1491 | } |
1492 | ||
1493 | EXPORT_SYMBOL(set_binfmt); | |
1494 | ||
1b0d300b XF |
1495 | static int expand_corename(struct core_name *cn) |
1496 | { | |
1497 | char *old_corename = cn->corename; | |
1498 | ||
1499 | cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); | |
1500 | cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL); | |
1501 | ||
1502 | if (!cn->corename) { | |
1503 | kfree(old_corename); | |
1504 | return -ENOMEM; | |
1505 | } | |
1506 | ||
1507 | return 0; | |
1508 | } | |
1509 | ||
1510 | static int cn_printf(struct core_name *cn, const char *fmt, ...) | |
1511 | { | |
1512 | char *cur; | |
1513 | int need; | |
1514 | int ret; | |
1515 | va_list arg; | |
1516 | ||
1517 | va_start(arg, fmt); | |
1518 | need = vsnprintf(NULL, 0, fmt, arg); | |
1519 | va_end(arg); | |
1520 | ||
1521 | if (likely(need < cn->size - cn->used - 1)) | |
1522 | goto out_printf; | |
1523 | ||
1524 | ret = expand_corename(cn); | |
1525 | if (ret) | |
1526 | goto expand_fail; | |
1527 | ||
1528 | out_printf: | |
1529 | cur = cn->corename + cn->used; | |
1530 | va_start(arg, fmt); | |
1531 | vsnprintf(cur, need + 1, fmt, arg); | |
1532 | va_end(arg); | |
1533 | cn->used += need; | |
1534 | return 0; | |
1535 | ||
1536 | expand_fail: | |
1537 | return ret; | |
1538 | } | |
1539 | ||
1da177e4 LT |
1540 | /* format_corename will inspect the pattern parameter, and output a |
1541 | * name into corename, which must have space for at least | |
1542 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1543 | */ | |
1b0d300b | 1544 | static int format_corename(struct core_name *cn, long signr) |
1da177e4 | 1545 | { |
86a264ab | 1546 | const struct cred *cred = current_cred(); |
565b9b14 ON |
1547 | const char *pat_ptr = core_pattern; |
1548 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 | 1549 | int pid_in_pattern = 0; |
1b0d300b XF |
1550 | int err = 0; |
1551 | ||
1552 | cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); | |
1553 | cn->corename = kmalloc(cn->size, GFP_KERNEL); | |
1554 | cn->used = 0; | |
1555 | ||
1556 | if (!cn->corename) | |
1557 | return -ENOMEM; | |
1da177e4 LT |
1558 | |
1559 | /* Repeat as long as we have more pattern to process and more output | |
1560 | space */ | |
1561 | while (*pat_ptr) { | |
1562 | if (*pat_ptr != '%') { | |
1b0d300b | 1563 | if (*pat_ptr == 0) |
1da177e4 | 1564 | goto out; |
1b0d300b | 1565 | err = cn_printf(cn, "%c", *pat_ptr++); |
1da177e4 LT |
1566 | } else { |
1567 | switch (*++pat_ptr) { | |
1b0d300b | 1568 | /* single % at the end, drop that */ |
1da177e4 LT |
1569 | case 0: |
1570 | goto out; | |
1571 | /* Double percent, output one percent */ | |
1572 | case '%': | |
1b0d300b | 1573 | err = cn_printf(cn, "%c", '%'); |
1da177e4 LT |
1574 | break; |
1575 | /* pid */ | |
1576 | case 'p': | |
1577 | pid_in_pattern = 1; | |
1b0d300b XF |
1578 | err = cn_printf(cn, "%d", |
1579 | task_tgid_vnr(current)); | |
1da177e4 LT |
1580 | break; |
1581 | /* uid */ | |
1582 | case 'u': | |
1b0d300b | 1583 | err = cn_printf(cn, "%d", cred->uid); |
1da177e4 LT |
1584 | break; |
1585 | /* gid */ | |
1586 | case 'g': | |
1b0d300b | 1587 | err = cn_printf(cn, "%d", cred->gid); |
1da177e4 LT |
1588 | break; |
1589 | /* signal that caused the coredump */ | |
1590 | case 's': | |
1b0d300b | 1591 | err = cn_printf(cn, "%ld", signr); |
1da177e4 LT |
1592 | break; |
1593 | /* UNIX time of coredump */ | |
1594 | case 't': { | |
1595 | struct timeval tv; | |
1596 | do_gettimeofday(&tv); | |
1b0d300b | 1597 | err = cn_printf(cn, "%lu", tv.tv_sec); |
1da177e4 LT |
1598 | break; |
1599 | } | |
1600 | /* hostname */ | |
1601 | case 'h': | |
1602 | down_read(&uts_sem); | |
1b0d300b XF |
1603 | err = cn_printf(cn, "%s", |
1604 | utsname()->nodename); | |
1da177e4 | 1605 | up_read(&uts_sem); |
1da177e4 LT |
1606 | break; |
1607 | /* executable */ | |
1608 | case 'e': | |
1b0d300b | 1609 | err = cn_printf(cn, "%s", current->comm); |
1da177e4 | 1610 | break; |
74aadce9 NH |
1611 | /* core limit size */ |
1612 | case 'c': | |
1b0d300b XF |
1613 | err = cn_printf(cn, "%lu", |
1614 | rlimit(RLIMIT_CORE)); | |
74aadce9 | 1615 | break; |
1da177e4 LT |
1616 | default: |
1617 | break; | |
1618 | } | |
1619 | ++pat_ptr; | |
1620 | } | |
1b0d300b XF |
1621 | |
1622 | if (err) | |
1623 | return err; | |
1da177e4 | 1624 | } |
1b0d300b | 1625 | |
1da177e4 LT |
1626 | /* Backward compatibility with core_uses_pid: |
1627 | * | |
1628 | * If core_pattern does not include a %p (as is the default) | |
1629 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1630 | * the filename. Do not do this for piped commands. */ |
6409324b | 1631 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1b0d300b XF |
1632 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); |
1633 | if (err) | |
1634 | return err; | |
1da177e4 | 1635 | } |
c4bbafda | 1636 | out: |
c4bbafda | 1637 | return ispipe; |
1da177e4 LT |
1638 | } |
1639 | ||
5c99cbf4 | 1640 | static int zap_process(struct task_struct *start, int exit_code) |
aceecc04 ON |
1641 | { |
1642 | struct task_struct *t; | |
8cd9c249 | 1643 | int nr = 0; |
281de339 | 1644 | |
d5f70c00 | 1645 | start->signal->flags = SIGNAL_GROUP_EXIT; |
5c99cbf4 | 1646 | start->signal->group_exit_code = exit_code; |
d5f70c00 | 1647 | start->signal->group_stop_count = 0; |
aceecc04 ON |
1648 | |
1649 | t = start; | |
1650 | do { | |
1651 | if (t != current && t->mm) { | |
281de339 ON |
1652 | sigaddset(&t->pending.signal, SIGKILL); |
1653 | signal_wake_up(t, 1); | |
8cd9c249 | 1654 | nr++; |
aceecc04 | 1655 | } |
e4901f92 | 1656 | } while_each_thread(start, t); |
8cd9c249 ON |
1657 | |
1658 | return nr; | |
aceecc04 ON |
1659 | } |
1660 | ||
dcf560c5 | 1661 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1662 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1663 | { |
1664 | struct task_struct *g, *p; | |
5debfa6d | 1665 | unsigned long flags; |
8cd9c249 | 1666 | int nr = -EAGAIN; |
dcf560c5 ON |
1667 | |
1668 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1669 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1670 | mm->core_state = core_state; |
5c99cbf4 | 1671 | nr = zap_process(tsk, exit_code); |
1da177e4 | 1672 | } |
dcf560c5 | 1673 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1674 | if (unlikely(nr < 0)) |
1675 | return nr; | |
1da177e4 | 1676 | |
8cd9c249 | 1677 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1678 | goto done; |
e4901f92 ON |
1679 | /* |
1680 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1681 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1682 | * lock, but this is safe wrt: |
1683 | * | |
1684 | * fork: | |
1685 | * None of sub-threads can fork after zap_process(leader). All | |
1686 | * processes which were created before this point should be | |
1687 | * visible to zap_threads() because copy_process() adds the new | |
1688 | * process to the tail of init_task.tasks list, and lock/unlock | |
1689 | * of ->siglock provides a memory barrier. | |
1690 | * | |
1691 | * do_exit: | |
1692 | * The caller holds mm->mmap_sem. This means that the task which | |
1693 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1694 | * its ->mm. | |
1695 | * | |
1696 | * de_thread: | |
1697 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1698 | * we must see either old or new leader, this does not matter. | |
1699 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1700 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1701 | * it can't fail. | |
1702 | * | |
1703 | * Note also that "g" can be the old leader with ->mm == NULL | |
1704 | * and already unhashed and thus removed from ->thread_group. | |
1705 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1706 | * clear the ->next pointer, we will find the new leader via | |
1707 | * next_thread(). | |
1708 | */ | |
7b1c6154 | 1709 | rcu_read_lock(); |
aceecc04 | 1710 | for_each_process(g) { |
5debfa6d ON |
1711 | if (g == tsk->group_leader) |
1712 | continue; | |
15b9f360 ON |
1713 | if (g->flags & PF_KTHREAD) |
1714 | continue; | |
aceecc04 ON |
1715 | p = g; |
1716 | do { | |
1717 | if (p->mm) { | |
15b9f360 | 1718 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1719 | lock_task_sighand(p, &flags); |
5c99cbf4 | 1720 | nr += zap_process(p, exit_code); |
5debfa6d ON |
1721 | unlock_task_sighand(p, &flags); |
1722 | } | |
aceecc04 ON |
1723 | break; |
1724 | } | |
e4901f92 | 1725 | } while_each_thread(g, p); |
aceecc04 | 1726 | } |
7b1c6154 | 1727 | rcu_read_unlock(); |
5debfa6d | 1728 | done: |
c5f1cc8c | 1729 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1730 | return nr; |
1da177e4 LT |
1731 | } |
1732 | ||
9d5b327b | 1733 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1734 | { |
dcf560c5 ON |
1735 | struct task_struct *tsk = current; |
1736 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1737 | struct completion *vfork_done; |
269b005a | 1738 | int core_waiters = -EBUSY; |
1da177e4 | 1739 | |
9d5b327b | 1740 | init_completion(&core_state->startup); |
b564daf8 ON |
1741 | core_state->dumper.task = tsk; |
1742 | core_state->dumper.next = NULL; | |
269b005a ON |
1743 | |
1744 | down_write(&mm->mmap_sem); | |
1745 | if (!mm->core_state) | |
1746 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); | |
2384f55f ON |
1747 | up_write(&mm->mmap_sem); |
1748 | ||
dcf560c5 ON |
1749 | if (unlikely(core_waiters < 0)) |
1750 | goto fail; | |
1751 | ||
1752 | /* | |
1753 | * Make sure nobody is waiting for us to release the VM, | |
1754 | * otherwise we can deadlock when we wait on each other | |
1755 | */ | |
1756 | vfork_done = tsk->vfork_done; | |
1757 | if (vfork_done) { | |
1758 | tsk->vfork_done = NULL; | |
1759 | complete(vfork_done); | |
1760 | } | |
1761 | ||
2384f55f | 1762 | if (core_waiters) |
9d5b327b | 1763 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1764 | fail: |
dcf560c5 | 1765 | return core_waiters; |
1da177e4 LT |
1766 | } |
1767 | ||
a94e2d40 ON |
1768 | static void coredump_finish(struct mm_struct *mm) |
1769 | { | |
1770 | struct core_thread *curr, *next; | |
1771 | struct task_struct *task; | |
1772 | ||
1773 | next = mm->core_state->dumper.next; | |
1774 | while ((curr = next) != NULL) { | |
1775 | next = curr->next; | |
1776 | task = curr->task; | |
1777 | /* | |
1778 | * see exit_mm(), curr->task must not see | |
1779 | * ->task == NULL before we read ->next. | |
1780 | */ | |
1781 | smp_mb(); | |
1782 | curr->task = NULL; | |
1783 | wake_up_process(task); | |
1784 | } | |
1785 | ||
1786 | mm->core_state = NULL; | |
1787 | } | |
1788 | ||
6c5d5238 KH |
1789 | /* |
1790 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1791 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1792 | * these bits are not changed atomically. So get_dumpable can observe the | |
1793 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1794 | * return either old dumpable or new one by paying attention to the order of | |
1795 | * modifying the bits. | |
1796 | * | |
1797 | * dumpable | mm->flags (binary) | |
1798 | * old new | initial interim final | |
1799 | * ---------+----------------------- | |
1800 | * 0 1 | 00 01 01 | |
1801 | * 0 2 | 00 10(*) 11 | |
1802 | * 1 0 | 01 00 00 | |
1803 | * 1 2 | 01 11 11 | |
1804 | * 2 0 | 11 10(*) 00 | |
1805 | * 2 1 | 11 11 01 | |
1806 | * | |
1807 | * (*) get_dumpable regards interim value of 10 as 11. | |
1808 | */ | |
1809 | void set_dumpable(struct mm_struct *mm, int value) | |
1810 | { | |
1811 | switch (value) { | |
1812 | case 0: | |
1813 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1814 | smp_wmb(); | |
1815 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1816 | break; | |
1817 | case 1: | |
1818 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1819 | smp_wmb(); | |
1820 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1821 | break; | |
1822 | case 2: | |
1823 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1824 | smp_wmb(); | |
1825 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1826 | break; | |
1827 | } | |
1828 | } | |
6c5d5238 | 1829 | |
30736a4d | 1830 | static int __get_dumpable(unsigned long mm_flags) |
6c5d5238 KH |
1831 | { |
1832 | int ret; | |
1833 | ||
30736a4d | 1834 | ret = mm_flags & MMF_DUMPABLE_MASK; |
6c5d5238 KH |
1835 | return (ret >= 2) ? 2 : ret; |
1836 | } | |
1837 | ||
30736a4d MH |
1838 | int get_dumpable(struct mm_struct *mm) |
1839 | { | |
1840 | return __get_dumpable(mm->flags); | |
1841 | } | |
1842 | ||
61be228a NH |
1843 | static void wait_for_dump_helpers(struct file *file) |
1844 | { | |
1845 | struct pipe_inode_info *pipe; | |
1846 | ||
1847 | pipe = file->f_path.dentry->d_inode->i_pipe; | |
1848 | ||
1849 | pipe_lock(pipe); | |
1850 | pipe->readers++; | |
1851 | pipe->writers--; | |
1852 | ||
1853 | while ((pipe->readers > 1) && (!signal_pending(current))) { | |
1854 | wake_up_interruptible_sync(&pipe->wait); | |
1855 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1856 | pipe_wait(pipe); | |
1857 | } | |
1858 | ||
1859 | pipe->readers--; | |
1860 | pipe->writers++; | |
1861 | pipe_unlock(pipe); | |
1862 | ||
1863 | } | |
1864 | ||
1865 | ||
898b374a NH |
1866 | /* |
1867 | * uhm_pipe_setup | |
1868 | * helper function to customize the process used | |
1869 | * to collect the core in userspace. Specifically | |
1870 | * it sets up a pipe and installs it as fd 0 (stdin) | |
1871 | * for the process. Returns 0 on success, or | |
1872 | * PTR_ERR on failure. | |
1873 | * Note that it also sets the core limit to 1. This | |
1874 | * is a special value that we use to trap recursive | |
1875 | * core dumps | |
1876 | */ | |
1877 | static int umh_pipe_setup(struct subprocess_info *info) | |
1878 | { | |
1879 | struct file *rp, *wp; | |
1880 | struct fdtable *fdt; | |
1881 | struct coredump_params *cp = (struct coredump_params *)info->data; | |
1882 | struct files_struct *cf = current->files; | |
1883 | ||
1884 | wp = create_write_pipe(0); | |
1885 | if (IS_ERR(wp)) | |
1886 | return PTR_ERR(wp); | |
1887 | ||
1888 | rp = create_read_pipe(wp, 0); | |
1889 | if (IS_ERR(rp)) { | |
1890 | free_write_pipe(wp); | |
1891 | return PTR_ERR(rp); | |
1892 | } | |
1893 | ||
1894 | cp->file = wp; | |
1895 | ||
1896 | sys_close(0); | |
1897 | fd_install(0, rp); | |
1898 | spin_lock(&cf->file_lock); | |
1899 | fdt = files_fdtable(cf); | |
1900 | FD_SET(0, fdt->open_fds); | |
1901 | FD_CLR(0, fdt->close_on_exec); | |
1902 | spin_unlock(&cf->file_lock); | |
1903 | ||
1904 | /* and disallow core files too */ | |
1905 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; | |
1906 | ||
1907 | return 0; | |
1908 | } | |
1909 | ||
8cd3ac3a | 1910 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1da177e4 | 1911 | { |
9d5b327b | 1912 | struct core_state core_state; |
1b0d300b | 1913 | struct core_name cn; |
1da177e4 LT |
1914 | struct mm_struct *mm = current->mm; |
1915 | struct linux_binfmt * binfmt; | |
d84f4f99 DH |
1916 | const struct cred *old_cred; |
1917 | struct cred *cred; | |
1da177e4 | 1918 | int retval = 0; |
d6e71144 | 1919 | int flag = 0; |
d5bf4c4f | 1920 | int ispipe; |
a293980c | 1921 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
f6151dfe MH |
1922 | struct coredump_params cprm = { |
1923 | .signr = signr, | |
1924 | .regs = regs, | |
d554ed89 | 1925 | .limit = rlimit(RLIMIT_CORE), |
30736a4d MH |
1926 | /* |
1927 | * We must use the same mm->flags while dumping core to avoid | |
1928 | * inconsistency of bit flags, since this flag is not protected | |
1929 | * by any locks. | |
1930 | */ | |
1931 | .mm_flags = mm->flags, | |
f6151dfe | 1932 | }; |
1da177e4 | 1933 | |
0a4ff8c2 SG |
1934 | audit_core_dumps(signr); |
1935 | ||
801460d0 | 1936 | binfmt = mm->binfmt; |
1da177e4 LT |
1937 | if (!binfmt || !binfmt->core_dump) |
1938 | goto fail; | |
269b005a ON |
1939 | if (!__get_dumpable(cprm.mm_flags)) |
1940 | goto fail; | |
d84f4f99 DH |
1941 | |
1942 | cred = prepare_creds(); | |
5e43aef5 | 1943 | if (!cred) |
d84f4f99 | 1944 | goto fail; |
d6e71144 AC |
1945 | /* |
1946 | * We cannot trust fsuid as being the "true" uid of the | |
1947 | * process nor do we know its entire history. We only know it | |
1948 | * was tainted so we dump it as root in mode 2. | |
1949 | */ | |
30736a4d MH |
1950 | if (__get_dumpable(cprm.mm_flags) == 2) { |
1951 | /* Setuid core dump mode */ | |
d6e71144 | 1952 | flag = O_EXCL; /* Stop rewrite attacks */ |
d84f4f99 | 1953 | cred->fsuid = 0; /* Dump root private */ |
d6e71144 | 1954 | } |
1291cf41 | 1955 | |
9d5b327b | 1956 | retval = coredump_wait(exit_code, &core_state); |
5e43aef5 ON |
1957 | if (retval < 0) |
1958 | goto fail_creds; | |
d84f4f99 DH |
1959 | |
1960 | old_cred = override_creds(cred); | |
1da177e4 LT |
1961 | |
1962 | /* | |
1963 | * Clear any false indication of pending signals that might | |
1964 | * be seen by the filesystem code called to write the core file. | |
1965 | */ | |
1da177e4 LT |
1966 | clear_thread_flag(TIF_SIGPENDING); |
1967 | ||
1b0d300b XF |
1968 | ispipe = format_corename(&cn, signr); |
1969 | ||
1970 | if (ispipe == -ENOMEM) { | |
1971 | printk(KERN_WARNING "format_corename failed\n"); | |
1972 | printk(KERN_WARNING "Aborting core\n"); | |
1973 | goto fail_corename; | |
1974 | } | |
725eae32 | 1975 | |
c4bbafda | 1976 | if (ispipe) { |
d5bf4c4f ON |
1977 | int dump_count; |
1978 | char **helper_argv; | |
1979 | ||
898b374a | 1980 | if (cprm.limit == 1) { |
725eae32 NH |
1981 | /* |
1982 | * Normally core limits are irrelevant to pipes, since | |
1983 | * we're not writing to the file system, but we use | |
898b374a NH |
1984 | * cprm.limit of 1 here as a speacial value. Any |
1985 | * non-1 limit gets set to RLIM_INFINITY below, but | |
725eae32 NH |
1986 | * a limit of 0 skips the dump. This is a consistent |
1987 | * way to catch recursive crashes. We can still crash | |
898b374a | 1988 | * if the core_pattern binary sets RLIM_CORE = !1 |
725eae32 NH |
1989 | * but it runs as root, and can do lots of stupid things |
1990 | * Note that we use task_tgid_vnr here to grab the pid | |
1991 | * of the process group leader. That way we get the | |
1992 | * right pid if a thread in a multi-threaded | |
1993 | * core_pattern process dies. | |
1994 | */ | |
1995 | printk(KERN_WARNING | |
898b374a | 1996 | "Process %d(%s) has RLIMIT_CORE set to 1\n", |
725eae32 NH |
1997 | task_tgid_vnr(current), current->comm); |
1998 | printk(KERN_WARNING "Aborting core\n"); | |
1999 | goto fail_unlock; | |
2000 | } | |
d5bf4c4f | 2001 | cprm.limit = RLIM_INFINITY; |
725eae32 | 2002 | |
a293980c NH |
2003 | dump_count = atomic_inc_return(&core_dump_count); |
2004 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { | |
2005 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", | |
2006 | task_tgid_vnr(current), current->comm); | |
2007 | printk(KERN_WARNING "Skipping core dump\n"); | |
2008 | goto fail_dropcount; | |
2009 | } | |
2010 | ||
1b0d300b | 2011 | helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); |
350eaf79 TH |
2012 | if (!helper_argv) { |
2013 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
2014 | __func__); | |
a293980c | 2015 | goto fail_dropcount; |
350eaf79 | 2016 | } |
32321137 | 2017 | |
d5bf4c4f ON |
2018 | retval = call_usermodehelper_fns(helper_argv[0], helper_argv, |
2019 | NULL, UMH_WAIT_EXEC, umh_pipe_setup, | |
2020 | NULL, &cprm); | |
2021 | argv_free(helper_argv); | |
2022 | if (retval) { | |
d025c9db | 2023 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1b0d300b | 2024 | cn.corename); |
d5bf4c4f | 2025 | goto close_fail; |
d025c9db | 2026 | } |
c7135411 ON |
2027 | } else { |
2028 | struct inode *inode; | |
2029 | ||
2030 | if (cprm.limit < binfmt->min_coredump) | |
2031 | goto fail_unlock; | |
2032 | ||
1b0d300b | 2033 | cprm.file = filp_open(cn.corename, |
6d4df677 AD |
2034 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
2035 | 0600); | |
c7135411 ON |
2036 | if (IS_ERR(cprm.file)) |
2037 | goto fail_unlock; | |
1da177e4 | 2038 | |
c7135411 ON |
2039 | inode = cprm.file->f_path.dentry->d_inode; |
2040 | if (inode->i_nlink > 1) | |
2041 | goto close_fail; | |
2042 | if (d_unhashed(cprm.file->f_path.dentry)) | |
2043 | goto close_fail; | |
2044 | /* | |
2045 | * AK: actually i see no reason to not allow this for named | |
2046 | * pipes etc, but keep the previous behaviour for now. | |
2047 | */ | |
2048 | if (!S_ISREG(inode->i_mode)) | |
2049 | goto close_fail; | |
2050 | /* | |
2051 | * Dont allow local users get cute and trick others to coredump | |
2052 | * into their pre-created files. | |
2053 | */ | |
2054 | if (inode->i_uid != current_fsuid()) | |
2055 | goto close_fail; | |
2056 | if (!cprm.file->f_op || !cprm.file->f_op->write) | |
2057 | goto close_fail; | |
2058 | if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) | |
2059 | goto close_fail; | |
2060 | } | |
1da177e4 | 2061 | |
c7135411 | 2062 | retval = binfmt->core_dump(&cprm); |
1da177e4 LT |
2063 | if (retval) |
2064 | current->signal->group_exit_code |= 0x80; | |
d5bf4c4f | 2065 | |
61be228a | 2066 | if (ispipe && core_pipe_limit) |
f6151dfe | 2067 | wait_for_dump_helpers(cprm.file); |
d5bf4c4f ON |
2068 | close_fail: |
2069 | if (cprm.file) | |
2070 | filp_close(cprm.file, NULL); | |
a293980c | 2071 | fail_dropcount: |
d5bf4c4f | 2072 | if (ispipe) |
a293980c | 2073 | atomic_dec(&core_dump_count); |
1da177e4 | 2074 | fail_unlock: |
1b0d300b XF |
2075 | kfree(cn.corename); |
2076 | fail_corename: | |
5e43aef5 | 2077 | coredump_finish(mm); |
d84f4f99 | 2078 | revert_creds(old_cred); |
5e43aef5 | 2079 | fail_creds: |
d84f4f99 | 2080 | put_cred(cred); |
1da177e4 | 2081 | fail: |
8cd3ac3a | 2082 | return; |
1da177e4 | 2083 | } |
3aa0ce82 LT |
2084 | |
2085 | /* | |
2086 | * Core dumping helper functions. These are the only things you should | |
2087 | * do on a core-file: use only these functions to write out all the | |
2088 | * necessary info. | |
2089 | */ | |
2090 | int dump_write(struct file *file, const void *addr, int nr) | |
2091 | { | |
2092 | return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; | |
2093 | } | |
8fd01d6c | 2094 | EXPORT_SYMBOL(dump_write); |
3aa0ce82 LT |
2095 | |
2096 | int dump_seek(struct file *file, loff_t off) | |
2097 | { | |
2098 | int ret = 1; | |
2099 | ||
2100 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { | |
2101 | if (file->f_op->llseek(file, off, SEEK_CUR) < 0) | |
2102 | return 0; | |
2103 | } else { | |
2104 | char *buf = (char *)get_zeroed_page(GFP_KERNEL); | |
2105 | ||
2106 | if (!buf) | |
2107 | return 0; | |
2108 | while (off > 0) { | |
2109 | unsigned long n = off; | |
2110 | ||
2111 | if (n > PAGE_SIZE) | |
2112 | n = PAGE_SIZE; | |
2113 | if (!dump_write(file, buf, n)) { | |
2114 | ret = 0; | |
2115 | break; | |
2116 | } | |
2117 | off -= n; | |
2118 | } | |
2119 | free_page((unsigned long)buf); | |
2120 | } | |
2121 | return ret; | |
2122 | } | |
8fd01d6c | 2123 | EXPORT_SYMBOL(dump_seek); |