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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 | |
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> | |
31 | #include <linux/smp_lock.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> |
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> |
1da177e4 LT |
54 | |
55 | #include <asm/uaccess.h> | |
56 | #include <asm/mmu_context.h> | |
b6a2fea3 | 57 | #include <asm/tlb.h> |
1da177e4 | 58 | |
702773b1 DW |
59 | #ifdef __alpha__ |
60 | /* for /sbin/loader handling in search_binary_handler() */ | |
61 | #include <linux/a.out.h> | |
62 | #endif | |
63 | ||
1da177e4 | 64 | int core_uses_pid; |
71ce92f3 | 65 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
d6e71144 AC |
66 | int suid_dumpable = 0; |
67 | ||
1da177e4 LT |
68 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
69 | ||
e4dc1b14 | 70 | static LIST_HEAD(formats); |
1da177e4 LT |
71 | static DEFINE_RWLOCK(binfmt_lock); |
72 | ||
73 | int register_binfmt(struct linux_binfmt * fmt) | |
74 | { | |
1da177e4 LT |
75 | if (!fmt) |
76 | return -EINVAL; | |
1da177e4 | 77 | write_lock(&binfmt_lock); |
e4dc1b14 | 78 | list_add(&fmt->lh, &formats); |
1da177e4 LT |
79 | write_unlock(&binfmt_lock); |
80 | return 0; | |
81 | } | |
82 | ||
83 | EXPORT_SYMBOL(register_binfmt); | |
84 | ||
f6b450d4 | 85 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 86 | { |
1da177e4 | 87 | write_lock(&binfmt_lock); |
e4dc1b14 | 88 | list_del(&fmt->lh); |
1da177e4 | 89 | write_unlock(&binfmt_lock); |
1da177e4 LT |
90 | } |
91 | ||
92 | EXPORT_SYMBOL(unregister_binfmt); | |
93 | ||
94 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
95 | { | |
96 | module_put(fmt->module); | |
97 | } | |
98 | ||
99 | /* | |
100 | * Note that a shared library must be both readable and executable due to | |
101 | * security reasons. | |
102 | * | |
103 | * Also note that we take the address to load from from the file itself. | |
104 | */ | |
105 | asmlinkage long sys_uselib(const char __user * library) | |
106 | { | |
964bd183 | 107 | struct file *file; |
1da177e4 | 108 | struct nameidata nd; |
964bd183 AV |
109 | char *tmp = getname(library); |
110 | int error = PTR_ERR(tmp); | |
111 | ||
112 | if (!IS_ERR(tmp)) { | |
113 | error = path_lookup_open(AT_FDCWD, tmp, | |
114 | LOOKUP_FOLLOW, &nd, | |
115 | FMODE_READ|FMODE_EXEC); | |
116 | putname(tmp); | |
117 | } | |
1da177e4 LT |
118 | if (error) |
119 | goto out; | |
120 | ||
121 | error = -EINVAL; | |
4ac91378 | 122 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) |
1da177e4 LT |
123 | goto exit; |
124 | ||
30524472 AV |
125 | error = -EACCES; |
126 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) | |
127 | goto exit; | |
128 | ||
b77b0646 | 129 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC | MAY_OPEN); |
1da177e4 LT |
130 | if (error) |
131 | goto exit; | |
132 | ||
abe8be3a | 133 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); |
1da177e4 LT |
134 | error = PTR_ERR(file); |
135 | if (IS_ERR(file)) | |
136 | goto out; | |
137 | ||
138 | error = -ENOEXEC; | |
139 | if(file->f_op) { | |
140 | struct linux_binfmt * fmt; | |
141 | ||
142 | read_lock(&binfmt_lock); | |
e4dc1b14 | 143 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
144 | if (!fmt->load_shlib) |
145 | continue; | |
146 | if (!try_module_get(fmt->module)) | |
147 | continue; | |
148 | read_unlock(&binfmt_lock); | |
149 | error = fmt->load_shlib(file); | |
150 | read_lock(&binfmt_lock); | |
151 | put_binfmt(fmt); | |
152 | if (error != -ENOEXEC) | |
153 | break; | |
154 | } | |
155 | read_unlock(&binfmt_lock); | |
156 | } | |
157 | fput(file); | |
158 | out: | |
159 | return error; | |
160 | exit: | |
834f2a4a | 161 | release_open_intent(&nd); |
1d957f9b | 162 | path_put(&nd.path); |
1da177e4 LT |
163 | goto out; |
164 | } | |
165 | ||
b6a2fea3 OW |
166 | #ifdef CONFIG_MMU |
167 | ||
168 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
169 | int write) | |
170 | { | |
171 | struct page *page; | |
172 | int ret; | |
173 | ||
174 | #ifdef CONFIG_STACK_GROWSUP | |
175 | if (write) { | |
176 | ret = expand_stack_downwards(bprm->vma, pos); | |
177 | if (ret < 0) | |
178 | return NULL; | |
179 | } | |
180 | #endif | |
181 | ret = get_user_pages(current, bprm->mm, pos, | |
182 | 1, write, 1, &page, NULL); | |
183 | if (ret <= 0) | |
184 | return NULL; | |
185 | ||
186 | if (write) { | |
b6a2fea3 | 187 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
188 | struct rlimit *rlim; |
189 | ||
190 | /* | |
191 | * We've historically supported up to 32 pages (ARG_MAX) | |
192 | * of argument strings even with small stacks | |
193 | */ | |
194 | if (size <= ARG_MAX) | |
195 | return page; | |
b6a2fea3 OW |
196 | |
197 | /* | |
198 | * Limit to 1/4-th the stack size for the argv+env strings. | |
199 | * This ensures that: | |
200 | * - the remaining binfmt code will not run out of stack space, | |
201 | * - the program will have a reasonable amount of stack left | |
202 | * to work from. | |
203 | */ | |
a64e715f | 204 | rlim = current->signal->rlim; |
b6a2fea3 OW |
205 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { |
206 | put_page(page); | |
207 | return NULL; | |
208 | } | |
209 | } | |
210 | ||
211 | return page; | |
212 | } | |
213 | ||
214 | static void put_arg_page(struct page *page) | |
215 | { | |
216 | put_page(page); | |
217 | } | |
218 | ||
219 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
220 | { | |
221 | } | |
222 | ||
223 | static void free_arg_pages(struct linux_binprm *bprm) | |
224 | { | |
225 | } | |
226 | ||
227 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
228 | struct page *page) | |
229 | { | |
230 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
231 | } | |
232 | ||
233 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
234 | { | |
235 | int err = -ENOMEM; | |
236 | struct vm_area_struct *vma = NULL; | |
237 | struct mm_struct *mm = bprm->mm; | |
238 | ||
239 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
240 | if (!vma) | |
241 | goto err; | |
242 | ||
243 | down_write(&mm->mmap_sem); | |
244 | vma->vm_mm = mm; | |
245 | ||
246 | /* | |
247 | * Place the stack at the largest stack address the architecture | |
248 | * supports. Later, we'll move this to an appropriate place. We don't | |
249 | * use STACK_TOP because that can depend on attributes which aren't | |
250 | * configured yet. | |
251 | */ | |
252 | vma->vm_end = STACK_TOP_MAX; | |
253 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
254 | ||
255 | vma->vm_flags = VM_STACK_FLAGS; | |
3ed75eb8 | 256 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
b6a2fea3 OW |
257 | err = insert_vm_struct(mm, vma); |
258 | if (err) { | |
259 | up_write(&mm->mmap_sem); | |
260 | goto err; | |
261 | } | |
262 | ||
263 | mm->stack_vm = mm->total_vm = 1; | |
264 | up_write(&mm->mmap_sem); | |
265 | ||
266 | bprm->p = vma->vm_end - sizeof(void *); | |
267 | ||
268 | return 0; | |
269 | ||
270 | err: | |
271 | if (vma) { | |
272 | bprm->vma = NULL; | |
273 | kmem_cache_free(vm_area_cachep, vma); | |
274 | } | |
275 | ||
276 | return err; | |
277 | } | |
278 | ||
279 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
280 | { | |
281 | return len <= MAX_ARG_STRLEN; | |
282 | } | |
283 | ||
284 | #else | |
285 | ||
286 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
287 | int write) | |
288 | { | |
289 | struct page *page; | |
290 | ||
291 | page = bprm->page[pos / PAGE_SIZE]; | |
292 | if (!page && write) { | |
293 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
294 | if (!page) | |
295 | return NULL; | |
296 | bprm->page[pos / PAGE_SIZE] = page; | |
297 | } | |
298 | ||
299 | return page; | |
300 | } | |
301 | ||
302 | static void put_arg_page(struct page *page) | |
303 | { | |
304 | } | |
305 | ||
306 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
307 | { | |
308 | if (bprm->page[i]) { | |
309 | __free_page(bprm->page[i]); | |
310 | bprm->page[i] = NULL; | |
311 | } | |
312 | } | |
313 | ||
314 | static void free_arg_pages(struct linux_binprm *bprm) | |
315 | { | |
316 | int i; | |
317 | ||
318 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
319 | free_arg_page(bprm, i); | |
320 | } | |
321 | ||
322 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
323 | struct page *page) | |
324 | { | |
325 | } | |
326 | ||
327 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
328 | { | |
329 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
330 | return 0; | |
331 | } | |
332 | ||
333 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
334 | { | |
335 | return len <= bprm->p; | |
336 | } | |
337 | ||
338 | #endif /* CONFIG_MMU */ | |
339 | ||
340 | /* | |
341 | * Create a new mm_struct and populate it with a temporary stack | |
342 | * vm_area_struct. We don't have enough context at this point to set the stack | |
343 | * flags, permissions, and offset, so we use temporary values. We'll update | |
344 | * them later in setup_arg_pages(). | |
345 | */ | |
346 | int bprm_mm_init(struct linux_binprm *bprm) | |
347 | { | |
348 | int err; | |
349 | struct mm_struct *mm = NULL; | |
350 | ||
351 | bprm->mm = mm = mm_alloc(); | |
352 | err = -ENOMEM; | |
353 | if (!mm) | |
354 | goto err; | |
355 | ||
356 | err = init_new_context(current, mm); | |
357 | if (err) | |
358 | goto err; | |
359 | ||
360 | err = __bprm_mm_init(bprm); | |
361 | if (err) | |
362 | goto err; | |
363 | ||
364 | return 0; | |
365 | ||
366 | err: | |
367 | if (mm) { | |
368 | bprm->mm = NULL; | |
369 | mmdrop(mm); | |
370 | } | |
371 | ||
372 | return err; | |
373 | } | |
374 | ||
1da177e4 LT |
375 | /* |
376 | * count() counts the number of strings in array ARGV. | |
377 | */ | |
378 | static int count(char __user * __user * argv, int max) | |
379 | { | |
380 | int i = 0; | |
381 | ||
382 | if (argv != NULL) { | |
383 | for (;;) { | |
384 | char __user * p; | |
385 | ||
386 | if (get_user(p, argv)) | |
387 | return -EFAULT; | |
388 | if (!p) | |
389 | break; | |
390 | argv++; | |
362e6663 | 391 | if (i++ >= max) |
1da177e4 LT |
392 | return -E2BIG; |
393 | cond_resched(); | |
394 | } | |
395 | } | |
396 | return i; | |
397 | } | |
398 | ||
399 | /* | |
b6a2fea3 OW |
400 | * 'copy_strings()' copies argument/environment strings from the old |
401 | * processes's memory to the new process's stack. The call to get_user_pages() | |
402 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 403 | */ |
75c96f85 AB |
404 | static int copy_strings(int argc, char __user * __user * argv, |
405 | struct linux_binprm *bprm) | |
1da177e4 LT |
406 | { |
407 | struct page *kmapped_page = NULL; | |
408 | char *kaddr = NULL; | |
b6a2fea3 | 409 | unsigned long kpos = 0; |
1da177e4 LT |
410 | int ret; |
411 | ||
412 | while (argc-- > 0) { | |
413 | char __user *str; | |
414 | int len; | |
415 | unsigned long pos; | |
416 | ||
417 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 418 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
419 | ret = -EFAULT; |
420 | goto out; | |
421 | } | |
422 | ||
b6a2fea3 | 423 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
424 | ret = -E2BIG; |
425 | goto out; | |
426 | } | |
427 | ||
b6a2fea3 | 428 | /* We're going to work our way backwords. */ |
1da177e4 | 429 | pos = bprm->p; |
b6a2fea3 OW |
430 | str += len; |
431 | bprm->p -= len; | |
1da177e4 LT |
432 | |
433 | while (len > 0) { | |
1da177e4 | 434 | int offset, bytes_to_copy; |
1da177e4 LT |
435 | |
436 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
437 | if (offset == 0) |
438 | offset = PAGE_SIZE; | |
439 | ||
440 | bytes_to_copy = offset; | |
441 | if (bytes_to_copy > len) | |
442 | bytes_to_copy = len; | |
443 | ||
444 | offset -= bytes_to_copy; | |
445 | pos -= bytes_to_copy; | |
446 | str -= bytes_to_copy; | |
447 | len -= bytes_to_copy; | |
448 | ||
449 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
450 | struct page *page; | |
451 | ||
452 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 453 | if (!page) { |
b6a2fea3 | 454 | ret = -E2BIG; |
1da177e4 LT |
455 | goto out; |
456 | } | |
1da177e4 | 457 | |
b6a2fea3 OW |
458 | if (kmapped_page) { |
459 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 460 | kunmap(kmapped_page); |
b6a2fea3 OW |
461 | put_arg_page(kmapped_page); |
462 | } | |
1da177e4 LT |
463 | kmapped_page = page; |
464 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
465 | kpos = pos & PAGE_MASK; |
466 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 467 | } |
b6a2fea3 | 468 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
469 | ret = -EFAULT; |
470 | goto out; | |
471 | } | |
1da177e4 LT |
472 | } |
473 | } | |
474 | ret = 0; | |
475 | out: | |
b6a2fea3 OW |
476 | if (kmapped_page) { |
477 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 478 | kunmap(kmapped_page); |
b6a2fea3 OW |
479 | put_arg_page(kmapped_page); |
480 | } | |
1da177e4 LT |
481 | return ret; |
482 | } | |
483 | ||
484 | /* | |
485 | * Like copy_strings, but get argv and its values from kernel memory. | |
486 | */ | |
487 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
488 | { | |
489 | int r; | |
490 | mm_segment_t oldfs = get_fs(); | |
491 | set_fs(KERNEL_DS); | |
492 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
493 | set_fs(oldfs); | |
494 | return r; | |
495 | } | |
1da177e4 LT |
496 | EXPORT_SYMBOL(copy_strings_kernel); |
497 | ||
498 | #ifdef CONFIG_MMU | |
b6a2fea3 | 499 | |
1da177e4 | 500 | /* |
b6a2fea3 OW |
501 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
502 | * the binfmt code determines where the new stack should reside, we shift it to | |
503 | * its final location. The process proceeds as follows: | |
1da177e4 | 504 | * |
b6a2fea3 OW |
505 | * 1) Use shift to calculate the new vma endpoints. |
506 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
507 | * arguments passed to subsequent functions are consistent. | |
508 | * 3) Move vma's page tables to the new range. | |
509 | * 4) Free up any cleared pgd range. | |
510 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 511 | */ |
b6a2fea3 | 512 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
513 | { |
514 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
515 | unsigned long old_start = vma->vm_start; |
516 | unsigned long old_end = vma->vm_end; | |
517 | unsigned long length = old_end - old_start; | |
518 | unsigned long new_start = old_start - shift; | |
519 | unsigned long new_end = old_end - shift; | |
520 | struct mmu_gather *tlb; | |
1da177e4 | 521 | |
b6a2fea3 | 522 | BUG_ON(new_start > new_end); |
1da177e4 | 523 | |
b6a2fea3 OW |
524 | /* |
525 | * ensure there are no vmas between where we want to go | |
526 | * and where we are | |
527 | */ | |
528 | if (vma != find_vma(mm, new_start)) | |
529 | return -EFAULT; | |
530 | ||
531 | /* | |
532 | * cover the whole range: [new_start, old_end) | |
533 | */ | |
534 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
535 | ||
536 | /* | |
537 | * move the page tables downwards, on failure we rely on | |
538 | * process cleanup to remove whatever mess we made. | |
539 | */ | |
540 | if (length != move_page_tables(vma, old_start, | |
541 | vma, new_start, length)) | |
542 | return -ENOMEM; | |
543 | ||
544 | lru_add_drain(); | |
545 | tlb = tlb_gather_mmu(mm, 0); | |
546 | if (new_end > old_start) { | |
547 | /* | |
548 | * when the old and new regions overlap clear from new_end. | |
549 | */ | |
42b77728 | 550 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
551 | vma->vm_next ? vma->vm_next->vm_start : 0); |
552 | } else { | |
553 | /* | |
554 | * otherwise, clean from old_start; this is done to not touch | |
555 | * the address space in [new_end, old_start) some architectures | |
556 | * have constraints on va-space that make this illegal (IA64) - | |
557 | * for the others its just a little faster. | |
558 | */ | |
42b77728 | 559 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 560 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 561 | } |
b6a2fea3 OW |
562 | tlb_finish_mmu(tlb, new_end, old_end); |
563 | ||
564 | /* | |
565 | * shrink the vma to just the new range. | |
566 | */ | |
567 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
568 | ||
569 | return 0; | |
1da177e4 LT |
570 | } |
571 | ||
572 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
573 | ||
b6a2fea3 OW |
574 | /* |
575 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
576 | * the stack is optionally relocated, and some extra space is added. | |
577 | */ | |
1da177e4 LT |
578 | int setup_arg_pages(struct linux_binprm *bprm, |
579 | unsigned long stack_top, | |
580 | int executable_stack) | |
581 | { | |
b6a2fea3 OW |
582 | unsigned long ret; |
583 | unsigned long stack_shift; | |
1da177e4 | 584 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
585 | struct vm_area_struct *vma = bprm->vma; |
586 | struct vm_area_struct *prev = NULL; | |
587 | unsigned long vm_flags; | |
588 | unsigned long stack_base; | |
1da177e4 LT |
589 | |
590 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
591 | /* Limit stack size to 1GB */ |
592 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
593 | if (stack_base > (1 << 30)) | |
594 | stack_base = 1 << 30; | |
1da177e4 | 595 | |
b6a2fea3 OW |
596 | /* Make sure we didn't let the argument array grow too large. */ |
597 | if (vma->vm_end - vma->vm_start > stack_base) | |
598 | return -ENOMEM; | |
1da177e4 | 599 | |
b6a2fea3 | 600 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 601 | |
b6a2fea3 OW |
602 | stack_shift = vma->vm_start - stack_base; |
603 | mm->arg_start = bprm->p - stack_shift; | |
604 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 605 | #else |
b6a2fea3 OW |
606 | stack_top = arch_align_stack(stack_top); |
607 | stack_top = PAGE_ALIGN(stack_top); | |
608 | stack_shift = vma->vm_end - stack_top; | |
609 | ||
610 | bprm->p -= stack_shift; | |
1da177e4 | 611 | mm->arg_start = bprm->p; |
1da177e4 LT |
612 | #endif |
613 | ||
1da177e4 | 614 | if (bprm->loader) |
b6a2fea3 OW |
615 | bprm->loader -= stack_shift; |
616 | bprm->exec -= stack_shift; | |
1da177e4 | 617 | |
1da177e4 | 618 | down_write(&mm->mmap_sem); |
96a8e13e | 619 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
620 | |
621 | /* | |
622 | * Adjust stack execute permissions; explicitly enable for | |
623 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
624 | * (arch default) otherwise. | |
625 | */ | |
626 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
627 | vm_flags |= VM_EXEC; | |
628 | else if (executable_stack == EXSTACK_DISABLE_X) | |
629 | vm_flags &= ~VM_EXEC; | |
630 | vm_flags |= mm->def_flags; | |
631 | ||
632 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
633 | vm_flags); | |
634 | if (ret) | |
635 | goto out_unlock; | |
636 | BUG_ON(prev != vma); | |
637 | ||
638 | /* Move stack pages down in memory. */ | |
639 | if (stack_shift) { | |
640 | ret = shift_arg_pages(vma, stack_shift); | |
641 | if (ret) { | |
1da177e4 | 642 | up_write(&mm->mmap_sem); |
1da177e4 LT |
643 | return ret; |
644 | } | |
1da177e4 LT |
645 | } |
646 | ||
b6a2fea3 OW |
647 | #ifdef CONFIG_STACK_GROWSUP |
648 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
649 | #else | |
650 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
651 | #endif | |
652 | ret = expand_stack(vma, stack_base); | |
653 | if (ret) | |
654 | ret = -EFAULT; | |
655 | ||
656 | out_unlock: | |
1da177e4 | 657 | up_write(&mm->mmap_sem); |
1da177e4 LT |
658 | return 0; |
659 | } | |
1da177e4 LT |
660 | EXPORT_SYMBOL(setup_arg_pages); |
661 | ||
1da177e4 LT |
662 | #endif /* CONFIG_MMU */ |
663 | ||
664 | struct file *open_exec(const char *name) | |
665 | { | |
666 | struct nameidata nd; | |
1da177e4 | 667 | struct file *file; |
e56b6a5d | 668 | int err; |
1da177e4 | 669 | |
e56b6a5d CH |
670 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, |
671 | FMODE_READ|FMODE_EXEC); | |
672 | if (err) | |
673 | goto out; | |
674 | ||
675 | err = -EACCES; | |
676 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) | |
677 | goto out_path_put; | |
678 | ||
30524472 AV |
679 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) |
680 | goto out_path_put; | |
681 | ||
e56b6a5d CH |
682 | err = vfs_permission(&nd, MAY_EXEC | MAY_OPEN); |
683 | if (err) | |
684 | goto out_path_put; | |
685 | ||
686 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); | |
687 | if (IS_ERR(file)) | |
688 | return file; | |
689 | ||
690 | err = deny_write_access(file); | |
691 | if (err) { | |
692 | fput(file); | |
693 | goto out; | |
1da177e4 | 694 | } |
1da177e4 | 695 | |
e56b6a5d CH |
696 | return file; |
697 | ||
698 | out_path_put: | |
699 | release_open_intent(&nd); | |
700 | path_put(&nd.path); | |
701 | out: | |
702 | return ERR_PTR(err); | |
703 | } | |
1da177e4 LT |
704 | EXPORT_SYMBOL(open_exec); |
705 | ||
706 | int kernel_read(struct file *file, unsigned long offset, | |
707 | char *addr, unsigned long count) | |
708 | { | |
709 | mm_segment_t old_fs; | |
710 | loff_t pos = offset; | |
711 | int result; | |
712 | ||
713 | old_fs = get_fs(); | |
714 | set_fs(get_ds()); | |
715 | /* The cast to a user pointer is valid due to the set_fs() */ | |
716 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
717 | set_fs(old_fs); | |
718 | return result; | |
719 | } | |
720 | ||
721 | EXPORT_SYMBOL(kernel_read); | |
722 | ||
723 | static int exec_mmap(struct mm_struct *mm) | |
724 | { | |
725 | struct task_struct *tsk; | |
726 | struct mm_struct * old_mm, *active_mm; | |
727 | ||
728 | /* Notify parent that we're no longer interested in the old VM */ | |
729 | tsk = current; | |
730 | old_mm = current->mm; | |
731 | mm_release(tsk, old_mm); | |
732 | ||
733 | if (old_mm) { | |
734 | /* | |
735 | * Make sure that if there is a core dump in progress | |
736 | * for the old mm, we get out and die instead of going | |
737 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 738 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
739 | */ |
740 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 741 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
742 | up_read(&old_mm->mmap_sem); |
743 | return -EINTR; | |
744 | } | |
745 | } | |
746 | task_lock(tsk); | |
747 | active_mm = tsk->active_mm; | |
748 | tsk->mm = mm; | |
749 | tsk->active_mm = mm; | |
750 | activate_mm(active_mm, mm); | |
751 | task_unlock(tsk); | |
752 | arch_pick_mmap_layout(mm); | |
753 | if (old_mm) { | |
754 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 755 | BUG_ON(active_mm != old_mm); |
31a78f23 | 756 | mm_update_next_owner(old_mm); |
1da177e4 LT |
757 | mmput(old_mm); |
758 | return 0; | |
759 | } | |
760 | mmdrop(active_mm); | |
761 | return 0; | |
762 | } | |
763 | ||
764 | /* | |
765 | * This function makes sure the current process has its own signal table, | |
766 | * so that flush_signal_handlers can later reset the handlers without | |
767 | * disturbing other processes. (Other processes might share the signal | |
768 | * table via the CLONE_SIGHAND option to clone().) | |
769 | */ | |
858119e1 | 770 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
771 | { |
772 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 773 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 774 | spinlock_t *lock = &oldsighand->siglock; |
329f7dba | 775 | struct task_struct *leader = NULL; |
1da177e4 LT |
776 | int count; |
777 | ||
aafe6c2a | 778 | if (thread_group_empty(tsk)) |
1da177e4 LT |
779 | goto no_thread_group; |
780 | ||
781 | /* | |
782 | * Kill all other threads in the thread group. | |
1da177e4 | 783 | */ |
1da177e4 | 784 | spin_lock_irq(lock); |
ed5d2cac | 785 | if (signal_group_exit(sig)) { |
1da177e4 LT |
786 | /* |
787 | * Another group action in progress, just | |
788 | * return so that the signal is processed. | |
789 | */ | |
790 | spin_unlock_irq(lock); | |
1da177e4 LT |
791 | return -EAGAIN; |
792 | } | |
ed5d2cac | 793 | sig->group_exit_task = tsk; |
aafe6c2a | 794 | zap_other_threads(tsk); |
1da177e4 | 795 | |
fea9d175 ON |
796 | /* Account for the thread group leader hanging around: */ |
797 | count = thread_group_leader(tsk) ? 1 : 2; | |
6db840fa | 798 | sig->notify_count = count; |
1da177e4 | 799 | while (atomic_read(&sig->count) > count) { |
1da177e4 LT |
800 | __set_current_state(TASK_UNINTERRUPTIBLE); |
801 | spin_unlock_irq(lock); | |
802 | schedule(); | |
803 | spin_lock_irq(lock); | |
804 | } | |
1da177e4 LT |
805 | spin_unlock_irq(lock); |
806 | ||
807 | /* | |
808 | * At this point all other threads have exited, all we have to | |
809 | * do is to wait for the thread group leader to become inactive, | |
810 | * and to assume its PID: | |
811 | */ | |
aafe6c2a | 812 | if (!thread_group_leader(tsk)) { |
aafe6c2a | 813 | leader = tsk->group_leader; |
6db840fa | 814 | |
2800d8d1 | 815 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
816 | for (;;) { |
817 | write_lock_irq(&tasklist_lock); | |
818 | if (likely(leader->exit_state)) | |
819 | break; | |
820 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
821 | write_unlock_irq(&tasklist_lock); | |
822 | schedule(); | |
823 | } | |
1da177e4 | 824 | |
f5e90281 RM |
825 | /* |
826 | * The only record we have of the real-time age of a | |
827 | * process, regardless of execs it's done, is start_time. | |
828 | * All the past CPU time is accumulated in signal_struct | |
829 | * from sister threads now dead. But in this non-leader | |
830 | * exec, nothing survives from the original leader thread, | |
831 | * whose birth marks the true age of this process now. | |
832 | * When we take on its identity by switching to its PID, we | |
833 | * also take its birthdate (always earlier than our own). | |
834 | */ | |
aafe6c2a | 835 | tsk->start_time = leader->start_time; |
f5e90281 | 836 | |
bac0abd6 PE |
837 | BUG_ON(!same_thread_group(leader, tsk)); |
838 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
839 | /* |
840 | * An exec() starts a new thread group with the | |
841 | * TGID of the previous thread group. Rehash the | |
842 | * two threads with a switched PID, and release | |
843 | * the former thread group leader: | |
844 | */ | |
d73d6529 EB |
845 | |
846 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
847 | * The old leader becomes a thread of the this thread group. |
848 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
849 | * is called. Odd but simple and correct. |
850 | */ | |
aafe6c2a EB |
851 | detach_pid(tsk, PIDTYPE_PID); |
852 | tsk->pid = leader->pid; | |
3743ca05 | 853 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
854 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
855 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
856 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 857 | |
aafe6c2a EB |
858 | tsk->group_leader = tsk; |
859 | leader->group_leader = tsk; | |
de12a787 | 860 | |
aafe6c2a | 861 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
862 | |
863 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
864 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
865 | |
866 | write_unlock_irq(&tasklist_lock); | |
ed5d2cac | 867 | } |
1da177e4 | 868 | |
6db840fa ON |
869 | sig->group_exit_task = NULL; |
870 | sig->notify_count = 0; | |
1da177e4 LT |
871 | |
872 | no_thread_group: | |
1da177e4 | 873 | exit_itimers(sig); |
cbaffba1 | 874 | flush_itimer_signals(); |
329f7dba ON |
875 | if (leader) |
876 | release_task(leader); | |
877 | ||
b2c903b8 ON |
878 | if (atomic_read(&oldsighand->count) != 1) { |
879 | struct sighand_struct *newsighand; | |
1da177e4 | 880 | /* |
b2c903b8 ON |
881 | * This ->sighand is shared with the CLONE_SIGHAND |
882 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 883 | */ |
b2c903b8 ON |
884 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
885 | if (!newsighand) | |
886 | return -ENOMEM; | |
887 | ||
1da177e4 LT |
888 | atomic_set(&newsighand->count, 1); |
889 | memcpy(newsighand->action, oldsighand->action, | |
890 | sizeof(newsighand->action)); | |
891 | ||
892 | write_lock_irq(&tasklist_lock); | |
893 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 894 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
895 | spin_unlock(&oldsighand->siglock); |
896 | write_unlock_irq(&tasklist_lock); | |
897 | ||
fba2afaa | 898 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
899 | } |
900 | ||
aafe6c2a | 901 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
902 | return 0; |
903 | } | |
0840a90d | 904 | |
1da177e4 LT |
905 | /* |
906 | * These functions flushes out all traces of the currently running executable | |
907 | * so that a new one can be started | |
908 | */ | |
858119e1 | 909 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
910 | { |
911 | long j = -1; | |
badf1662 | 912 | struct fdtable *fdt; |
1da177e4 LT |
913 | |
914 | spin_lock(&files->file_lock); | |
915 | for (;;) { | |
916 | unsigned long set, i; | |
917 | ||
918 | j++; | |
919 | i = j * __NFDBITS; | |
badf1662 | 920 | fdt = files_fdtable(files); |
bbea9f69 | 921 | if (i >= fdt->max_fds) |
1da177e4 | 922 | break; |
badf1662 | 923 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
924 | if (!set) |
925 | continue; | |
badf1662 | 926 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
927 | spin_unlock(&files->file_lock); |
928 | for ( ; set ; i++,set >>= 1) { | |
929 | if (set & 1) { | |
930 | sys_close(i); | |
931 | } | |
932 | } | |
933 | spin_lock(&files->file_lock); | |
934 | ||
935 | } | |
936 | spin_unlock(&files->file_lock); | |
937 | } | |
938 | ||
59714d65 | 939 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
940 | { |
941 | /* buf must be at least sizeof(tsk->comm) in size */ | |
942 | task_lock(tsk); | |
943 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
944 | task_unlock(tsk); | |
59714d65 | 945 | return buf; |
1da177e4 LT |
946 | } |
947 | ||
948 | void set_task_comm(struct task_struct *tsk, char *buf) | |
949 | { | |
950 | task_lock(tsk); | |
951 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
952 | task_unlock(tsk); | |
953 | } | |
954 | ||
955 | int flush_old_exec(struct linux_binprm * bprm) | |
956 | { | |
957 | char * name; | |
958 | int i, ch, retval; | |
1da177e4 LT |
959 | char tcomm[sizeof(current->comm)]; |
960 | ||
961 | /* | |
962 | * Make sure we have a private signal table and that | |
963 | * we are unassociated from the previous thread group. | |
964 | */ | |
965 | retval = de_thread(current); | |
966 | if (retval) | |
967 | goto out; | |
968 | ||
925d1c40 MH |
969 | set_mm_exe_file(bprm->mm, bprm->file); |
970 | ||
1da177e4 LT |
971 | /* |
972 | * Release all of the old mmap stuff | |
973 | */ | |
974 | retval = exec_mmap(bprm->mm); | |
975 | if (retval) | |
fd8328be | 976 | goto out; |
1da177e4 LT |
977 | |
978 | bprm->mm = NULL; /* We're using it now */ | |
979 | ||
980 | /* This is the point of no return */ | |
1da177e4 LT |
981 | current->sas_ss_sp = current->sas_ss_size = 0; |
982 | ||
983 | if (current->euid == current->uid && current->egid == current->gid) | |
6c5d5238 | 984 | set_dumpable(current->mm, 1); |
d6e71144 | 985 | else |
6c5d5238 | 986 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 987 | |
1da177e4 | 988 | name = bprm->filename; |
36772092 PBG |
989 | |
990 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
991 | for (i=0; (ch = *(name++)) != '\0';) { |
992 | if (ch == '/') | |
36772092 | 993 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
994 | else |
995 | if (i < (sizeof(tcomm) - 1)) | |
996 | tcomm[i++] = ch; | |
997 | } | |
998 | tcomm[i] = '\0'; | |
999 | set_task_comm(current, tcomm); | |
1000 | ||
1001 | current->flags &= ~PF_RANDOMIZE; | |
1002 | flush_thread(); | |
1003 | ||
0551fbd2 BH |
1004 | /* Set the new mm task size. We have to do that late because it may |
1005 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1006 | * some architectures like powerpc | |
1007 | */ | |
1008 | current->mm->task_size = TASK_SIZE; | |
1009 | ||
d2d56c5f MH |
1010 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { |
1011 | suid_keys(current); | |
1012 | set_dumpable(current->mm, suid_dumpable); | |
1013 | current->pdeath_signal = 0; | |
1014 | } else if (file_permission(bprm->file, MAY_READ) || | |
1015 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
1da177e4 | 1016 | suid_keys(current); |
6c5d5238 | 1017 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1018 | } |
1019 | ||
1020 | /* An exec changes our domain. We are no longer part of the thread | |
1021 | group */ | |
1022 | ||
1023 | current->self_exec_id++; | |
1024 | ||
1025 | flush_signal_handlers(current, 0); | |
1026 | flush_old_files(current->files); | |
1027 | ||
1028 | return 0; | |
1029 | ||
1da177e4 LT |
1030 | out: |
1031 | return retval; | |
1032 | } | |
1033 | ||
1034 | EXPORT_SYMBOL(flush_old_exec); | |
1035 | ||
1036 | /* | |
1037 | * Fill the binprm structure from the inode. | |
1038 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1039 | */ | |
1040 | int prepare_binprm(struct linux_binprm *bprm) | |
1041 | { | |
1042 | int mode; | |
0f7fc9e4 | 1043 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1044 | int retval; |
1045 | ||
1046 | mode = inode->i_mode; | |
1da177e4 LT |
1047 | if (bprm->file->f_op == NULL) |
1048 | return -EACCES; | |
1049 | ||
1050 | bprm->e_uid = current->euid; | |
1051 | bprm->e_gid = current->egid; | |
1052 | ||
0f7fc9e4 | 1053 | if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1054 | /* Set-uid? */ |
1055 | if (mode & S_ISUID) { | |
1056 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1057 | bprm->e_uid = inode->i_uid; | |
1058 | } | |
1059 | ||
1060 | /* Set-gid? */ | |
1061 | /* | |
1062 | * If setgid is set but no group execute bit then this | |
1063 | * is a candidate for mandatory locking, not a setgid | |
1064 | * executable. | |
1065 | */ | |
1066 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1067 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1068 | bprm->e_gid = inode->i_gid; | |
1069 | } | |
1070 | } | |
1071 | ||
1072 | /* fill in binprm security blob */ | |
1073 | retval = security_bprm_set(bprm); | |
1074 | if (retval) | |
1075 | return retval; | |
1076 | ||
1077 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
1078 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
1079 | } | |
1080 | ||
1081 | EXPORT_SYMBOL(prepare_binprm); | |
1082 | ||
858119e1 | 1083 | static int unsafe_exec(struct task_struct *p) |
1da177e4 | 1084 | { |
6341c393 RM |
1085 | int unsafe = tracehook_unsafe_exec(p); |
1086 | ||
1da177e4 LT |
1087 | if (atomic_read(&p->fs->count) > 1 || |
1088 | atomic_read(&p->files->count) > 1 || | |
1089 | atomic_read(&p->sighand->count) > 1) | |
1090 | unsafe |= LSM_UNSAFE_SHARE; | |
1091 | ||
1092 | return unsafe; | |
1093 | } | |
1094 | ||
1095 | void compute_creds(struct linux_binprm *bprm) | |
1096 | { | |
1097 | int unsafe; | |
1098 | ||
d2d56c5f | 1099 | if (bprm->e_uid != current->uid) { |
1da177e4 | 1100 | suid_keys(current); |
d2d56c5f MH |
1101 | current->pdeath_signal = 0; |
1102 | } | |
1da177e4 LT |
1103 | exec_keys(current); |
1104 | ||
1105 | task_lock(current); | |
1106 | unsafe = unsafe_exec(current); | |
1107 | security_bprm_apply_creds(bprm, unsafe); | |
1108 | task_unlock(current); | |
1109 | security_bprm_post_apply_creds(bprm); | |
1110 | } | |
1da177e4 LT |
1111 | EXPORT_SYMBOL(compute_creds); |
1112 | ||
4fc75ff4 NP |
1113 | /* |
1114 | * Arguments are '\0' separated strings found at the location bprm->p | |
1115 | * points to; chop off the first by relocating brpm->p to right after | |
1116 | * the first '\0' encountered. | |
1117 | */ | |
b6a2fea3 | 1118 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1119 | { |
b6a2fea3 OW |
1120 | int ret = 0; |
1121 | unsigned long offset; | |
1122 | char *kaddr; | |
1123 | struct page *page; | |
4fc75ff4 | 1124 | |
b6a2fea3 OW |
1125 | if (!bprm->argc) |
1126 | return 0; | |
1da177e4 | 1127 | |
b6a2fea3 OW |
1128 | do { |
1129 | offset = bprm->p & ~PAGE_MASK; | |
1130 | page = get_arg_page(bprm, bprm->p, 0); | |
1131 | if (!page) { | |
1132 | ret = -EFAULT; | |
1133 | goto out; | |
1134 | } | |
1135 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1136 | |
b6a2fea3 OW |
1137 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1138 | offset++, bprm->p++) | |
1139 | ; | |
4fc75ff4 | 1140 | |
b6a2fea3 OW |
1141 | kunmap_atomic(kaddr, KM_USER0); |
1142 | put_arg_page(page); | |
4fc75ff4 | 1143 | |
b6a2fea3 OW |
1144 | if (offset == PAGE_SIZE) |
1145 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1146 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1147 | |
b6a2fea3 OW |
1148 | bprm->p++; |
1149 | bprm->argc--; | |
1150 | ret = 0; | |
4fc75ff4 | 1151 | |
b6a2fea3 OW |
1152 | out: |
1153 | return ret; | |
1da177e4 | 1154 | } |
1da177e4 LT |
1155 | EXPORT_SYMBOL(remove_arg_zero); |
1156 | ||
1157 | /* | |
1158 | * cycle the list of binary formats handler, until one recognizes the image | |
1159 | */ | |
1160 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1161 | { | |
85f33466 | 1162 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1163 | int try,retval; |
1164 | struct linux_binfmt *fmt; | |
702773b1 | 1165 | #ifdef __alpha__ |
1da177e4 LT |
1166 | /* handle /sbin/loader.. */ |
1167 | { | |
1168 | struct exec * eh = (struct exec *) bprm->buf; | |
1169 | ||
1170 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1171 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1172 | { | |
1173 | struct file * file; | |
1174 | unsigned long loader; | |
1175 | ||
1176 | allow_write_access(bprm->file); | |
1177 | fput(bprm->file); | |
1178 | bprm->file = NULL; | |
1179 | ||
b6a2fea3 | 1180 | loader = bprm->vma->vm_end - sizeof(void *); |
1da177e4 LT |
1181 | |
1182 | file = open_exec("/sbin/loader"); | |
1183 | retval = PTR_ERR(file); | |
1184 | if (IS_ERR(file)) | |
1185 | return retval; | |
1186 | ||
1187 | /* Remember if the application is TASO. */ | |
53112488 | 1188 | bprm->taso = eh->ah.entry < 0x100000000UL; |
1da177e4 LT |
1189 | |
1190 | bprm->file = file; | |
1191 | bprm->loader = loader; | |
1192 | retval = prepare_binprm(bprm); | |
1193 | if (retval<0) | |
1194 | return retval; | |
1195 | /* should call search_binary_handler recursively here, | |
1196 | but it does not matter */ | |
1197 | } | |
1198 | } | |
1199 | #endif | |
1200 | retval = security_bprm_check(bprm); | |
1201 | if (retval) | |
1202 | return retval; | |
1203 | ||
1204 | /* kernel module loader fixup */ | |
1205 | /* so we don't try to load run modprobe in kernel space. */ | |
1206 | set_fs(USER_DS); | |
473ae30b AV |
1207 | |
1208 | retval = audit_bprm(bprm); | |
1209 | if (retval) | |
1210 | return retval; | |
1211 | ||
1da177e4 LT |
1212 | retval = -ENOENT; |
1213 | for (try=0; try<2; try++) { | |
1214 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1215 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1216 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1217 | if (!fn) | |
1218 | continue; | |
1219 | if (!try_module_get(fmt->module)) | |
1220 | continue; | |
1221 | read_unlock(&binfmt_lock); | |
1222 | retval = fn(bprm, regs); | |
85f33466 RM |
1223 | /* |
1224 | * Restore the depth counter to its starting value | |
1225 | * in this call, so we don't have to rely on every | |
1226 | * load_binary function to restore it on return. | |
1227 | */ | |
1228 | bprm->recursion_depth = depth; | |
1da177e4 | 1229 | if (retval >= 0) { |
85f33466 RM |
1230 | if (depth == 0) |
1231 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1232 | put_binfmt(fmt); |
1233 | allow_write_access(bprm->file); | |
1234 | if (bprm->file) | |
1235 | fput(bprm->file); | |
1236 | bprm->file = NULL; | |
1237 | current->did_exec = 1; | |
9f46080c | 1238 | proc_exec_connector(current); |
1da177e4 LT |
1239 | return retval; |
1240 | } | |
1241 | read_lock(&binfmt_lock); | |
1242 | put_binfmt(fmt); | |
1243 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1244 | break; | |
1245 | if (!bprm->file) { | |
1246 | read_unlock(&binfmt_lock); | |
1247 | return retval; | |
1248 | } | |
1249 | } | |
1250 | read_unlock(&binfmt_lock); | |
1251 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1252 | break; | |
5f4123be JB |
1253 | #ifdef CONFIG_MODULES |
1254 | } else { | |
1da177e4 LT |
1255 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1256 | if (printable(bprm->buf[0]) && | |
1257 | printable(bprm->buf[1]) && | |
1258 | printable(bprm->buf[2]) && | |
1259 | printable(bprm->buf[3])) | |
1260 | break; /* -ENOEXEC */ | |
1261 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1262 | #endif | |
1263 | } | |
1264 | } | |
1265 | return retval; | |
1266 | } | |
1267 | ||
1268 | EXPORT_SYMBOL(search_binary_handler); | |
1269 | ||
08a6fac1 AV |
1270 | void free_bprm(struct linux_binprm *bprm) |
1271 | { | |
1272 | free_arg_pages(bprm); | |
1273 | kfree(bprm); | |
1274 | } | |
1275 | ||
1da177e4 LT |
1276 | /* |
1277 | * sys_execve() executes a new program. | |
1278 | */ | |
1279 | int do_execve(char * filename, | |
1280 | char __user *__user *argv, | |
1281 | char __user *__user *envp, | |
1282 | struct pt_regs * regs) | |
1283 | { | |
1284 | struct linux_binprm *bprm; | |
1285 | struct file *file; | |
3b125388 | 1286 | struct files_struct *displaced; |
1da177e4 | 1287 | int retval; |
1da177e4 | 1288 | |
3b125388 | 1289 | retval = unshare_files(&displaced); |
fd8328be AV |
1290 | if (retval) |
1291 | goto out_ret; | |
1292 | ||
1da177e4 | 1293 | retval = -ENOMEM; |
11b0b5ab | 1294 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1295 | if (!bprm) |
fd8328be | 1296 | goto out_files; |
1da177e4 LT |
1297 | |
1298 | file = open_exec(filename); | |
1299 | retval = PTR_ERR(file); | |
1300 | if (IS_ERR(file)) | |
1301 | goto out_kfree; | |
1302 | ||
1303 | sched_exec(); | |
1304 | ||
1da177e4 LT |
1305 | bprm->file = file; |
1306 | bprm->filename = filename; | |
1307 | bprm->interp = filename; | |
1da177e4 | 1308 | |
b6a2fea3 OW |
1309 | retval = bprm_mm_init(bprm); |
1310 | if (retval) | |
1311 | goto out_file; | |
1da177e4 | 1312 | |
b6a2fea3 | 1313 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 LT |
1314 | if ((retval = bprm->argc) < 0) |
1315 | goto out_mm; | |
1316 | ||
b6a2fea3 | 1317 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 LT |
1318 | if ((retval = bprm->envc) < 0) |
1319 | goto out_mm; | |
1320 | ||
1321 | retval = security_bprm_alloc(bprm); | |
1322 | if (retval) | |
1323 | goto out; | |
1324 | ||
1325 | retval = prepare_binprm(bprm); | |
1326 | if (retval < 0) | |
1327 | goto out; | |
1328 | ||
1329 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1330 | if (retval < 0) | |
1331 | goto out; | |
1332 | ||
1333 | bprm->exec = bprm->p; | |
1334 | retval = copy_strings(bprm->envc, envp, bprm); | |
1335 | if (retval < 0) | |
1336 | goto out; | |
1337 | ||
1338 | retval = copy_strings(bprm->argc, argv, bprm); | |
1339 | if (retval < 0) | |
1340 | goto out; | |
1341 | ||
7b34e428 | 1342 | current->flags &= ~PF_KTHREAD; |
1da177e4 LT |
1343 | retval = search_binary_handler(bprm,regs); |
1344 | if (retval >= 0) { | |
1da177e4 LT |
1345 | /* execve success */ |
1346 | security_bprm_free(bprm); | |
1347 | acct_update_integrals(current); | |
08a6fac1 | 1348 | free_bprm(bprm); |
3b125388 AV |
1349 | if (displaced) |
1350 | put_files_struct(displaced); | |
1da177e4 LT |
1351 | return retval; |
1352 | } | |
1353 | ||
1354 | out: | |
1da177e4 LT |
1355 | if (bprm->security) |
1356 | security_bprm_free(bprm); | |
1357 | ||
1358 | out_mm: | |
1359 | if (bprm->mm) | |
b6a2fea3 | 1360 | mmput (bprm->mm); |
1da177e4 LT |
1361 | |
1362 | out_file: | |
1363 | if (bprm->file) { | |
1364 | allow_write_access(bprm->file); | |
1365 | fput(bprm->file); | |
1366 | } | |
1da177e4 | 1367 | out_kfree: |
08a6fac1 | 1368 | free_bprm(bprm); |
1da177e4 | 1369 | |
fd8328be | 1370 | out_files: |
3b125388 AV |
1371 | if (displaced) |
1372 | reset_files_struct(displaced); | |
1da177e4 LT |
1373 | out_ret: |
1374 | return retval; | |
1375 | } | |
1376 | ||
1377 | int set_binfmt(struct linux_binfmt *new) | |
1378 | { | |
1379 | struct linux_binfmt *old = current->binfmt; | |
1380 | ||
1381 | if (new) { | |
1382 | if (!try_module_get(new->module)) | |
1383 | return -1; | |
1384 | } | |
1385 | current->binfmt = new; | |
1386 | if (old) | |
1387 | module_put(old->module); | |
1388 | return 0; | |
1389 | } | |
1390 | ||
1391 | EXPORT_SYMBOL(set_binfmt); | |
1392 | ||
1da177e4 LT |
1393 | /* format_corename will inspect the pattern parameter, and output a |
1394 | * name into corename, which must have space for at least | |
1395 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1396 | */ | |
6409324b | 1397 | static int format_corename(char *corename, long signr) |
1da177e4 | 1398 | { |
565b9b14 ON |
1399 | const char *pat_ptr = core_pattern; |
1400 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 LT |
1401 | char *out_ptr = corename; |
1402 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1403 | int rc; | |
1404 | int pid_in_pattern = 0; | |
1405 | ||
1406 | /* Repeat as long as we have more pattern to process and more output | |
1407 | space */ | |
1408 | while (*pat_ptr) { | |
1409 | if (*pat_ptr != '%') { | |
1410 | if (out_ptr == out_end) | |
1411 | goto out; | |
1412 | *out_ptr++ = *pat_ptr++; | |
1413 | } else { | |
1414 | switch (*++pat_ptr) { | |
1415 | case 0: | |
1416 | goto out; | |
1417 | /* Double percent, output one percent */ | |
1418 | case '%': | |
1419 | if (out_ptr == out_end) | |
1420 | goto out; | |
1421 | *out_ptr++ = '%'; | |
1422 | break; | |
1423 | /* pid */ | |
1424 | case 'p': | |
1425 | pid_in_pattern = 1; | |
1426 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1427 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1428 | if (rc > out_end - out_ptr) |
1429 | goto out; | |
1430 | out_ptr += rc; | |
1431 | break; | |
1432 | /* uid */ | |
1433 | case 'u': | |
1434 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1435 | "%d", current->uid); | |
1436 | if (rc > out_end - out_ptr) | |
1437 | goto out; | |
1438 | out_ptr += rc; | |
1439 | break; | |
1440 | /* gid */ | |
1441 | case 'g': | |
1442 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1443 | "%d", current->gid); | |
1444 | if (rc > out_end - out_ptr) | |
1445 | goto out; | |
1446 | out_ptr += rc; | |
1447 | break; | |
1448 | /* signal that caused the coredump */ | |
1449 | case 's': | |
1450 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1451 | "%ld", signr); | |
1452 | if (rc > out_end - out_ptr) | |
1453 | goto out; | |
1454 | out_ptr += rc; | |
1455 | break; | |
1456 | /* UNIX time of coredump */ | |
1457 | case 't': { | |
1458 | struct timeval tv; | |
1459 | do_gettimeofday(&tv); | |
1460 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1461 | "%lu", tv.tv_sec); | |
1462 | if (rc > out_end - out_ptr) | |
1463 | goto out; | |
1464 | out_ptr += rc; | |
1465 | break; | |
1466 | } | |
1467 | /* hostname */ | |
1468 | case 'h': | |
1469 | down_read(&uts_sem); | |
1470 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1471 | "%s", utsname()->nodename); |
1da177e4 LT |
1472 | up_read(&uts_sem); |
1473 | if (rc > out_end - out_ptr) | |
1474 | goto out; | |
1475 | out_ptr += rc; | |
1476 | break; | |
1477 | /* executable */ | |
1478 | case 'e': | |
1479 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1480 | "%s", current->comm); | |
1481 | if (rc > out_end - out_ptr) | |
1482 | goto out; | |
1483 | out_ptr += rc; | |
1484 | break; | |
74aadce9 NH |
1485 | /* core limit size */ |
1486 | case 'c': | |
1487 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1488 | "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); | |
1489 | if (rc > out_end - out_ptr) | |
1490 | goto out; | |
1491 | out_ptr += rc; | |
1492 | break; | |
1da177e4 LT |
1493 | default: |
1494 | break; | |
1495 | } | |
1496 | ++pat_ptr; | |
1497 | } | |
1498 | } | |
1499 | /* Backward compatibility with core_uses_pid: | |
1500 | * | |
1501 | * If core_pattern does not include a %p (as is the default) | |
1502 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1503 | * the filename. Do not do this for piped commands. */ |
6409324b | 1504 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1da177e4 | 1505 | rc = snprintf(out_ptr, out_end - out_ptr, |
b488893a | 1506 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1507 | if (rc > out_end - out_ptr) |
1508 | goto out; | |
1509 | out_ptr += rc; | |
1510 | } | |
c4bbafda | 1511 | out: |
1da177e4 | 1512 | *out_ptr = 0; |
c4bbafda | 1513 | return ispipe; |
1da177e4 LT |
1514 | } |
1515 | ||
8cd9c249 | 1516 | static int zap_process(struct task_struct *start) |
aceecc04 ON |
1517 | { |
1518 | struct task_struct *t; | |
8cd9c249 | 1519 | int nr = 0; |
281de339 | 1520 | |
d5f70c00 ON |
1521 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1522 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1523 | |
1524 | t = start; | |
1525 | do { | |
1526 | if (t != current && t->mm) { | |
281de339 ON |
1527 | sigaddset(&t->pending.signal, SIGKILL); |
1528 | signal_wake_up(t, 1); | |
8cd9c249 | 1529 | nr++; |
aceecc04 | 1530 | } |
e4901f92 | 1531 | } while_each_thread(start, t); |
8cd9c249 ON |
1532 | |
1533 | return nr; | |
aceecc04 ON |
1534 | } |
1535 | ||
dcf560c5 | 1536 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1537 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1538 | { |
1539 | struct task_struct *g, *p; | |
5debfa6d | 1540 | unsigned long flags; |
8cd9c249 | 1541 | int nr = -EAGAIN; |
dcf560c5 ON |
1542 | |
1543 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1544 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1545 | mm->core_state = core_state; |
dcf560c5 | 1546 | tsk->signal->group_exit_code = exit_code; |
8cd9c249 | 1547 | nr = zap_process(tsk); |
1da177e4 | 1548 | } |
dcf560c5 | 1549 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1550 | if (unlikely(nr < 0)) |
1551 | return nr; | |
1da177e4 | 1552 | |
8cd9c249 | 1553 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1554 | goto done; |
e4901f92 ON |
1555 | /* |
1556 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1557 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1558 | * lock, but this is safe wrt: |
1559 | * | |
1560 | * fork: | |
1561 | * None of sub-threads can fork after zap_process(leader). All | |
1562 | * processes which were created before this point should be | |
1563 | * visible to zap_threads() because copy_process() adds the new | |
1564 | * process to the tail of init_task.tasks list, and lock/unlock | |
1565 | * of ->siglock provides a memory barrier. | |
1566 | * | |
1567 | * do_exit: | |
1568 | * The caller holds mm->mmap_sem. This means that the task which | |
1569 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1570 | * its ->mm. | |
1571 | * | |
1572 | * de_thread: | |
1573 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1574 | * we must see either old or new leader, this does not matter. | |
1575 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1576 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1577 | * it can't fail. | |
1578 | * | |
1579 | * Note also that "g" can be the old leader with ->mm == NULL | |
1580 | * and already unhashed and thus removed from ->thread_group. | |
1581 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1582 | * clear the ->next pointer, we will find the new leader via | |
1583 | * next_thread(). | |
1584 | */ | |
7b1c6154 | 1585 | rcu_read_lock(); |
aceecc04 | 1586 | for_each_process(g) { |
5debfa6d ON |
1587 | if (g == tsk->group_leader) |
1588 | continue; | |
15b9f360 ON |
1589 | if (g->flags & PF_KTHREAD) |
1590 | continue; | |
aceecc04 ON |
1591 | p = g; |
1592 | do { | |
1593 | if (p->mm) { | |
15b9f360 | 1594 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1595 | lock_task_sighand(p, &flags); |
8cd9c249 | 1596 | nr += zap_process(p); |
5debfa6d ON |
1597 | unlock_task_sighand(p, &flags); |
1598 | } | |
aceecc04 ON |
1599 | break; |
1600 | } | |
e4901f92 | 1601 | } while_each_thread(g, p); |
aceecc04 | 1602 | } |
7b1c6154 | 1603 | rcu_read_unlock(); |
5debfa6d | 1604 | done: |
c5f1cc8c | 1605 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1606 | return nr; |
1da177e4 LT |
1607 | } |
1608 | ||
9d5b327b | 1609 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1610 | { |
dcf560c5 ON |
1611 | struct task_struct *tsk = current; |
1612 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1613 | struct completion *vfork_done; |
2384f55f | 1614 | int core_waiters; |
1da177e4 | 1615 | |
9d5b327b | 1616 | init_completion(&core_state->startup); |
b564daf8 ON |
1617 | core_state->dumper.task = tsk; |
1618 | core_state->dumper.next = NULL; | |
9d5b327b | 1619 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
2384f55f ON |
1620 | up_write(&mm->mmap_sem); |
1621 | ||
dcf560c5 ON |
1622 | if (unlikely(core_waiters < 0)) |
1623 | goto fail; | |
1624 | ||
1625 | /* | |
1626 | * Make sure nobody is waiting for us to release the VM, | |
1627 | * otherwise we can deadlock when we wait on each other | |
1628 | */ | |
1629 | vfork_done = tsk->vfork_done; | |
1630 | if (vfork_done) { | |
1631 | tsk->vfork_done = NULL; | |
1632 | complete(vfork_done); | |
1633 | } | |
1634 | ||
2384f55f | 1635 | if (core_waiters) |
9d5b327b | 1636 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1637 | fail: |
dcf560c5 | 1638 | return core_waiters; |
1da177e4 LT |
1639 | } |
1640 | ||
a94e2d40 ON |
1641 | static void coredump_finish(struct mm_struct *mm) |
1642 | { | |
1643 | struct core_thread *curr, *next; | |
1644 | struct task_struct *task; | |
1645 | ||
1646 | next = mm->core_state->dumper.next; | |
1647 | while ((curr = next) != NULL) { | |
1648 | next = curr->next; | |
1649 | task = curr->task; | |
1650 | /* | |
1651 | * see exit_mm(), curr->task must not see | |
1652 | * ->task == NULL before we read ->next. | |
1653 | */ | |
1654 | smp_mb(); | |
1655 | curr->task = NULL; | |
1656 | wake_up_process(task); | |
1657 | } | |
1658 | ||
1659 | mm->core_state = NULL; | |
1660 | } | |
1661 | ||
6c5d5238 KH |
1662 | /* |
1663 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1664 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1665 | * these bits are not changed atomically. So get_dumpable can observe the | |
1666 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1667 | * return either old dumpable or new one by paying attention to the order of | |
1668 | * modifying the bits. | |
1669 | * | |
1670 | * dumpable | mm->flags (binary) | |
1671 | * old new | initial interim final | |
1672 | * ---------+----------------------- | |
1673 | * 0 1 | 00 01 01 | |
1674 | * 0 2 | 00 10(*) 11 | |
1675 | * 1 0 | 01 00 00 | |
1676 | * 1 2 | 01 11 11 | |
1677 | * 2 0 | 11 10(*) 00 | |
1678 | * 2 1 | 11 11 01 | |
1679 | * | |
1680 | * (*) get_dumpable regards interim value of 10 as 11. | |
1681 | */ | |
1682 | void set_dumpable(struct mm_struct *mm, int value) | |
1683 | { | |
1684 | switch (value) { | |
1685 | case 0: | |
1686 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1687 | smp_wmb(); | |
1688 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1689 | break; | |
1690 | case 1: | |
1691 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1692 | smp_wmb(); | |
1693 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1694 | break; | |
1695 | case 2: | |
1696 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1697 | smp_wmb(); | |
1698 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1699 | break; | |
1700 | } | |
1701 | } | |
6c5d5238 KH |
1702 | |
1703 | int get_dumpable(struct mm_struct *mm) | |
1704 | { | |
1705 | int ret; | |
1706 | ||
1707 | ret = mm->flags & 0x3; | |
1708 | return (ret >= 2) ? 2 : ret; | |
1709 | } | |
1710 | ||
1da177e4 LT |
1711 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) |
1712 | { | |
9d5b327b | 1713 | struct core_state core_state; |
1da177e4 LT |
1714 | char corename[CORENAME_MAX_SIZE + 1]; |
1715 | struct mm_struct *mm = current->mm; | |
1716 | struct linux_binfmt * binfmt; | |
1717 | struct inode * inode; | |
1718 | struct file * file; | |
1719 | int retval = 0; | |
d6e71144 AC |
1720 | int fsuid = current->fsuid; |
1721 | int flag = 0; | |
d025c9db | 1722 | int ispipe = 0; |
7dc0b22e | 1723 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
74aadce9 NH |
1724 | char **helper_argv = NULL; |
1725 | int helper_argc = 0; | |
1726 | char *delimit; | |
1da177e4 | 1727 | |
0a4ff8c2 SG |
1728 | audit_core_dumps(signr); |
1729 | ||
1da177e4 LT |
1730 | binfmt = current->binfmt; |
1731 | if (!binfmt || !binfmt->core_dump) | |
1732 | goto fail; | |
1733 | down_write(&mm->mmap_sem); | |
00ec99da RM |
1734 | /* |
1735 | * If another thread got here first, or we are not dumpable, bail out. | |
1736 | */ | |
999d9fc1 | 1737 | if (mm->core_state || !get_dumpable(mm)) { |
1da177e4 LT |
1738 | up_write(&mm->mmap_sem); |
1739 | goto fail; | |
1740 | } | |
d6e71144 AC |
1741 | |
1742 | /* | |
1743 | * We cannot trust fsuid as being the "true" uid of the | |
1744 | * process nor do we know its entire history. We only know it | |
1745 | * was tainted so we dump it as root in mode 2. | |
1746 | */ | |
6c5d5238 | 1747 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 AC |
1748 | flag = O_EXCL; /* Stop rewrite attacks */ |
1749 | current->fsuid = 0; /* Dump root private */ | |
1750 | } | |
1291cf41 | 1751 | |
9d5b327b | 1752 | retval = coredump_wait(exit_code, &core_state); |
dcf560c5 | 1753 | if (retval < 0) |
1291cf41 | 1754 | goto fail; |
1da177e4 LT |
1755 | |
1756 | /* | |
1757 | * Clear any false indication of pending signals that might | |
1758 | * be seen by the filesystem code called to write the core file. | |
1759 | */ | |
1da177e4 LT |
1760 | clear_thread_flag(TIF_SIGPENDING); |
1761 | ||
1da177e4 LT |
1762 | /* |
1763 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1764 | * uses lock_kernel() | |
1765 | */ | |
1766 | lock_kernel(); | |
6409324b | 1767 | ispipe = format_corename(corename, signr); |
1da177e4 | 1768 | unlock_kernel(); |
7dc0b22e NH |
1769 | /* |
1770 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1771 | * to a pipe. Since we're not writing directly to the filesystem | |
1772 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1773 | * created unless the pipe reader choses to write out the core file | |
1774 | * at which point file size limits and permissions will be imposed | |
1775 | * as it does with any other process | |
1776 | */ | |
74aadce9 | 1777 | if ((!ispipe) && (core_limit < binfmt->min_coredump)) |
7dc0b22e NH |
1778 | goto fail_unlock; |
1779 | ||
c4bbafda | 1780 | if (ispipe) { |
74aadce9 NH |
1781 | helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc); |
1782 | /* Terminate the string before the first option */ | |
1783 | delimit = strchr(corename, ' '); | |
1784 | if (delimit) | |
1785 | *delimit = '\0'; | |
32321137 NH |
1786 | delimit = strrchr(helper_argv[0], '/'); |
1787 | if (delimit) | |
1788 | delimit++; | |
1789 | else | |
1790 | delimit = helper_argv[0]; | |
1791 | if (!strcmp(delimit, current->comm)) { | |
1792 | printk(KERN_NOTICE "Recursive core dump detected, " | |
1793 | "aborting\n"); | |
1794 | goto fail_unlock; | |
1795 | } | |
1796 | ||
1797 | core_limit = RLIM_INFINITY; | |
1798 | ||
d025c9db | 1799 | /* SIGPIPE can happen, but it's just never processed */ |
32321137 NH |
1800 | if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, |
1801 | &file)) { | |
d025c9db AK |
1802 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1803 | corename); | |
1804 | goto fail_unlock; | |
1805 | } | |
d025c9db AK |
1806 | } else |
1807 | file = filp_open(corename, | |
6d4df677 AD |
1808 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1809 | 0600); | |
1da177e4 LT |
1810 | if (IS_ERR(file)) |
1811 | goto fail_unlock; | |
0f7fc9e4 | 1812 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1813 | if (inode->i_nlink > 1) |
1814 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1815 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1816 | goto close_fail; |
1817 | ||
d025c9db AK |
1818 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1819 | but keep the previous behaviour for now. */ | |
1820 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 | 1821 | goto close_fail; |
c46f739d IM |
1822 | /* |
1823 | * Dont allow local users get cute and trick others to coredump | |
1824 | * into their pre-created files: | |
1825 | */ | |
1826 | if (inode->i_uid != current->fsuid) | |
1827 | goto close_fail; | |
1da177e4 LT |
1828 | if (!file->f_op) |
1829 | goto close_fail; | |
1830 | if (!file->f_op->write) | |
1831 | goto close_fail; | |
0f7fc9e4 | 1832 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1833 | goto close_fail; |
1834 | ||
7dc0b22e | 1835 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1836 | |
1837 | if (retval) | |
1838 | current->signal->group_exit_code |= 0x80; | |
1839 | close_fail: | |
1840 | filp_close(file, NULL); | |
1841 | fail_unlock: | |
74aadce9 NH |
1842 | if (helper_argv) |
1843 | argv_free(helper_argv); | |
1844 | ||
d6e71144 | 1845 | current->fsuid = fsuid; |
a94e2d40 | 1846 | coredump_finish(mm); |
1da177e4 LT |
1847 | fail: |
1848 | return retval; | |
1849 | } |