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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> | |
27 | #include <linux/mman.h> | |
28 | #include <linux/a.out.h> | |
29 | #include <linux/stat.h> | |
30 | #include <linux/fcntl.h> | |
31 | #include <linux/smp_lock.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/pagemap.h> | |
34 | #include <linux/highmem.h> | |
35 | #include <linux/spinlock.h> | |
36 | #include <linux/key.h> | |
37 | #include <linux/personality.h> | |
38 | #include <linux/binfmts.h> | |
39 | #include <linux/swap.h> | |
40 | #include <linux/utsname.h> | |
84d73786 | 41 | #include <linux/pid_namespace.h> |
1da177e4 LT |
42 | #include <linux/module.h> |
43 | #include <linux/namei.h> | |
44 | #include <linux/proc_fs.h> | |
45 | #include <linux/ptrace.h> | |
46 | #include <linux/mount.h> | |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
49 | #include <linux/rmap.h> | |
8f0ab514 | 50 | #include <linux/tsacct_kern.h> |
9f46080c | 51 | #include <linux/cn_proc.h> |
473ae30b | 52 | #include <linux/audit.h> |
1da177e4 LT |
53 | |
54 | #include <asm/uaccess.h> | |
55 | #include <asm/mmu_context.h> | |
b6a2fea3 | 56 | #include <asm/tlb.h> |
1da177e4 LT |
57 | |
58 | #ifdef CONFIG_KMOD | |
59 | #include <linux/kmod.h> | |
60 | #endif | |
61 | ||
62 | int core_uses_pid; | |
71ce92f3 | 63 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
d6e71144 AC |
64 | int suid_dumpable = 0; |
65 | ||
66 | EXPORT_SYMBOL(suid_dumpable); | |
1da177e4 LT |
67 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
68 | ||
e4dc1b14 | 69 | static LIST_HEAD(formats); |
1da177e4 LT |
70 | static DEFINE_RWLOCK(binfmt_lock); |
71 | ||
72 | int register_binfmt(struct linux_binfmt * fmt) | |
73 | { | |
1da177e4 LT |
74 | if (!fmt) |
75 | return -EINVAL; | |
1da177e4 | 76 | write_lock(&binfmt_lock); |
e4dc1b14 | 77 | list_add(&fmt->lh, &formats); |
1da177e4 LT |
78 | write_unlock(&binfmt_lock); |
79 | return 0; | |
80 | } | |
81 | ||
82 | EXPORT_SYMBOL(register_binfmt); | |
83 | ||
84 | int unregister_binfmt(struct linux_binfmt * fmt) | |
85 | { | |
1da177e4 | 86 | write_lock(&binfmt_lock); |
e4dc1b14 | 87 | list_del(&fmt->lh); |
1da177e4 | 88 | write_unlock(&binfmt_lock); |
e4dc1b14 | 89 | return 0; |
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 | { | |
107 | struct file * file; | |
108 | struct nameidata nd; | |
109 | int error; | |
110 | ||
b500531e | 111 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
112 | if (error) |
113 | goto out; | |
114 | ||
492c8b33 CH |
115 | error = -EACCES; |
116 | if (nd.mnt->mnt_flags & MNT_NOEXEC) | |
117 | goto exit; | |
1da177e4 LT |
118 | error = -EINVAL; |
119 | if (!S_ISREG(nd.dentry->d_inode->i_mode)) | |
120 | goto exit; | |
121 | ||
e4543edd | 122 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC); |
1da177e4 LT |
123 | if (error) |
124 | goto exit; | |
125 | ||
834f2a4a | 126 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
127 | error = PTR_ERR(file); |
128 | if (IS_ERR(file)) | |
129 | goto out; | |
130 | ||
131 | error = -ENOEXEC; | |
132 | if(file->f_op) { | |
133 | struct linux_binfmt * fmt; | |
134 | ||
135 | read_lock(&binfmt_lock); | |
e4dc1b14 | 136 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
137 | if (!fmt->load_shlib) |
138 | continue; | |
139 | if (!try_module_get(fmt->module)) | |
140 | continue; | |
141 | read_unlock(&binfmt_lock); | |
142 | error = fmt->load_shlib(file); | |
143 | read_lock(&binfmt_lock); | |
144 | put_binfmt(fmt); | |
145 | if (error != -ENOEXEC) | |
146 | break; | |
147 | } | |
148 | read_unlock(&binfmt_lock); | |
149 | } | |
150 | fput(file); | |
151 | out: | |
152 | return error; | |
153 | exit: | |
834f2a4a | 154 | release_open_intent(&nd); |
1da177e4 LT |
155 | path_release(&nd); |
156 | goto out; | |
157 | } | |
158 | ||
b6a2fea3 OW |
159 | #ifdef CONFIG_MMU |
160 | ||
161 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
162 | int write) | |
163 | { | |
164 | struct page *page; | |
165 | int ret; | |
166 | ||
167 | #ifdef CONFIG_STACK_GROWSUP | |
168 | if (write) { | |
169 | ret = expand_stack_downwards(bprm->vma, pos); | |
170 | if (ret < 0) | |
171 | return NULL; | |
172 | } | |
173 | #endif | |
174 | ret = get_user_pages(current, bprm->mm, pos, | |
175 | 1, write, 1, &page, NULL); | |
176 | if (ret <= 0) | |
177 | return NULL; | |
178 | ||
179 | if (write) { | |
180 | struct rlimit *rlim = current->signal->rlim; | |
181 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
182 | ||
183 | /* | |
184 | * Limit to 1/4-th the stack size for the argv+env strings. | |
185 | * This ensures that: | |
186 | * - the remaining binfmt code will not run out of stack space, | |
187 | * - the program will have a reasonable amount of stack left | |
188 | * to work from. | |
189 | */ | |
190 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { | |
191 | put_page(page); | |
192 | return NULL; | |
193 | } | |
194 | } | |
195 | ||
196 | return page; | |
197 | } | |
198 | ||
199 | static void put_arg_page(struct page *page) | |
200 | { | |
201 | put_page(page); | |
202 | } | |
203 | ||
204 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
205 | { | |
206 | } | |
207 | ||
208 | static void free_arg_pages(struct linux_binprm *bprm) | |
209 | { | |
210 | } | |
211 | ||
212 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
213 | struct page *page) | |
214 | { | |
215 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
216 | } | |
217 | ||
218 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
219 | { | |
220 | int err = -ENOMEM; | |
221 | struct vm_area_struct *vma = NULL; | |
222 | struct mm_struct *mm = bprm->mm; | |
223 | ||
224 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
225 | if (!vma) | |
226 | goto err; | |
227 | ||
228 | down_write(&mm->mmap_sem); | |
229 | vma->vm_mm = mm; | |
230 | ||
231 | /* | |
232 | * Place the stack at the largest stack address the architecture | |
233 | * supports. Later, we'll move this to an appropriate place. We don't | |
234 | * use STACK_TOP because that can depend on attributes which aren't | |
235 | * configured yet. | |
236 | */ | |
237 | vma->vm_end = STACK_TOP_MAX; | |
238 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
239 | ||
240 | vma->vm_flags = VM_STACK_FLAGS; | |
241 | vma->vm_page_prot = protection_map[vma->vm_flags & 0x7]; | |
242 | err = insert_vm_struct(mm, vma); | |
243 | if (err) { | |
244 | up_write(&mm->mmap_sem); | |
245 | goto err; | |
246 | } | |
247 | ||
248 | mm->stack_vm = mm->total_vm = 1; | |
249 | up_write(&mm->mmap_sem); | |
250 | ||
251 | bprm->p = vma->vm_end - sizeof(void *); | |
252 | ||
253 | return 0; | |
254 | ||
255 | err: | |
256 | if (vma) { | |
257 | bprm->vma = NULL; | |
258 | kmem_cache_free(vm_area_cachep, vma); | |
259 | } | |
260 | ||
261 | return err; | |
262 | } | |
263 | ||
264 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
265 | { | |
266 | return len <= MAX_ARG_STRLEN; | |
267 | } | |
268 | ||
269 | #else | |
270 | ||
271 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
272 | int write) | |
273 | { | |
274 | struct page *page; | |
275 | ||
276 | page = bprm->page[pos / PAGE_SIZE]; | |
277 | if (!page && write) { | |
278 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
279 | if (!page) | |
280 | return NULL; | |
281 | bprm->page[pos / PAGE_SIZE] = page; | |
282 | } | |
283 | ||
284 | return page; | |
285 | } | |
286 | ||
287 | static void put_arg_page(struct page *page) | |
288 | { | |
289 | } | |
290 | ||
291 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
292 | { | |
293 | if (bprm->page[i]) { | |
294 | __free_page(bprm->page[i]); | |
295 | bprm->page[i] = NULL; | |
296 | } | |
297 | } | |
298 | ||
299 | static void free_arg_pages(struct linux_binprm *bprm) | |
300 | { | |
301 | int i; | |
302 | ||
303 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
304 | free_arg_page(bprm, i); | |
305 | } | |
306 | ||
307 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
308 | struct page *page) | |
309 | { | |
310 | } | |
311 | ||
312 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
313 | { | |
314 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
315 | return 0; | |
316 | } | |
317 | ||
318 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
319 | { | |
320 | return len <= bprm->p; | |
321 | } | |
322 | ||
323 | #endif /* CONFIG_MMU */ | |
324 | ||
325 | /* | |
326 | * Create a new mm_struct and populate it with a temporary stack | |
327 | * vm_area_struct. We don't have enough context at this point to set the stack | |
328 | * flags, permissions, and offset, so we use temporary values. We'll update | |
329 | * them later in setup_arg_pages(). | |
330 | */ | |
331 | int bprm_mm_init(struct linux_binprm *bprm) | |
332 | { | |
333 | int err; | |
334 | struct mm_struct *mm = NULL; | |
335 | ||
336 | bprm->mm = mm = mm_alloc(); | |
337 | err = -ENOMEM; | |
338 | if (!mm) | |
339 | goto err; | |
340 | ||
341 | err = init_new_context(current, mm); | |
342 | if (err) | |
343 | goto err; | |
344 | ||
345 | err = __bprm_mm_init(bprm); | |
346 | if (err) | |
347 | goto err; | |
348 | ||
349 | return 0; | |
350 | ||
351 | err: | |
352 | if (mm) { | |
353 | bprm->mm = NULL; | |
354 | mmdrop(mm); | |
355 | } | |
356 | ||
357 | return err; | |
358 | } | |
359 | ||
1da177e4 LT |
360 | /* |
361 | * count() counts the number of strings in array ARGV. | |
362 | */ | |
363 | static int count(char __user * __user * argv, int max) | |
364 | { | |
365 | int i = 0; | |
366 | ||
367 | if (argv != NULL) { | |
368 | for (;;) { | |
369 | char __user * p; | |
370 | ||
371 | if (get_user(p, argv)) | |
372 | return -EFAULT; | |
373 | if (!p) | |
374 | break; | |
375 | argv++; | |
376 | if(++i > max) | |
377 | return -E2BIG; | |
378 | cond_resched(); | |
379 | } | |
380 | } | |
381 | return i; | |
382 | } | |
383 | ||
384 | /* | |
b6a2fea3 OW |
385 | * 'copy_strings()' copies argument/environment strings from the old |
386 | * processes's memory to the new process's stack. The call to get_user_pages() | |
387 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 388 | */ |
75c96f85 AB |
389 | static int copy_strings(int argc, char __user * __user * argv, |
390 | struct linux_binprm *bprm) | |
1da177e4 LT |
391 | { |
392 | struct page *kmapped_page = NULL; | |
393 | char *kaddr = NULL; | |
b6a2fea3 | 394 | unsigned long kpos = 0; |
1da177e4 LT |
395 | int ret; |
396 | ||
397 | while (argc-- > 0) { | |
398 | char __user *str; | |
399 | int len; | |
400 | unsigned long pos; | |
401 | ||
402 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 403 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
404 | ret = -EFAULT; |
405 | goto out; | |
406 | } | |
407 | ||
b6a2fea3 | 408 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
409 | ret = -E2BIG; |
410 | goto out; | |
411 | } | |
412 | ||
b6a2fea3 | 413 | /* We're going to work our way backwords. */ |
1da177e4 | 414 | pos = bprm->p; |
b6a2fea3 OW |
415 | str += len; |
416 | bprm->p -= len; | |
1da177e4 LT |
417 | |
418 | while (len > 0) { | |
1da177e4 | 419 | int offset, bytes_to_copy; |
1da177e4 LT |
420 | |
421 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
422 | if (offset == 0) |
423 | offset = PAGE_SIZE; | |
424 | ||
425 | bytes_to_copy = offset; | |
426 | if (bytes_to_copy > len) | |
427 | bytes_to_copy = len; | |
428 | ||
429 | offset -= bytes_to_copy; | |
430 | pos -= bytes_to_copy; | |
431 | str -= bytes_to_copy; | |
432 | len -= bytes_to_copy; | |
433 | ||
434 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
435 | struct page *page; | |
436 | ||
437 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 438 | if (!page) { |
b6a2fea3 | 439 | ret = -E2BIG; |
1da177e4 LT |
440 | goto out; |
441 | } | |
1da177e4 | 442 | |
b6a2fea3 OW |
443 | if (kmapped_page) { |
444 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 445 | kunmap(kmapped_page); |
b6a2fea3 OW |
446 | put_arg_page(kmapped_page); |
447 | } | |
1da177e4 LT |
448 | kmapped_page = page; |
449 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
450 | kpos = pos & PAGE_MASK; |
451 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 452 | } |
b6a2fea3 | 453 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
454 | ret = -EFAULT; |
455 | goto out; | |
456 | } | |
1da177e4 LT |
457 | } |
458 | } | |
459 | ret = 0; | |
460 | out: | |
b6a2fea3 OW |
461 | if (kmapped_page) { |
462 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 463 | kunmap(kmapped_page); |
b6a2fea3 OW |
464 | put_arg_page(kmapped_page); |
465 | } | |
1da177e4 LT |
466 | return ret; |
467 | } | |
468 | ||
469 | /* | |
470 | * Like copy_strings, but get argv and its values from kernel memory. | |
471 | */ | |
472 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
473 | { | |
474 | int r; | |
475 | mm_segment_t oldfs = get_fs(); | |
476 | set_fs(KERNEL_DS); | |
477 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
478 | set_fs(oldfs); | |
479 | return r; | |
480 | } | |
1da177e4 LT |
481 | EXPORT_SYMBOL(copy_strings_kernel); |
482 | ||
483 | #ifdef CONFIG_MMU | |
b6a2fea3 | 484 | |
1da177e4 | 485 | /* |
b6a2fea3 OW |
486 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
487 | * the binfmt code determines where the new stack should reside, we shift it to | |
488 | * its final location. The process proceeds as follows: | |
1da177e4 | 489 | * |
b6a2fea3 OW |
490 | * 1) Use shift to calculate the new vma endpoints. |
491 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
492 | * arguments passed to subsequent functions are consistent. | |
493 | * 3) Move vma's page tables to the new range. | |
494 | * 4) Free up any cleared pgd range. | |
495 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 496 | */ |
b6a2fea3 | 497 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
498 | { |
499 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
500 | unsigned long old_start = vma->vm_start; |
501 | unsigned long old_end = vma->vm_end; | |
502 | unsigned long length = old_end - old_start; | |
503 | unsigned long new_start = old_start - shift; | |
504 | unsigned long new_end = old_end - shift; | |
505 | struct mmu_gather *tlb; | |
1da177e4 | 506 | |
b6a2fea3 | 507 | BUG_ON(new_start > new_end); |
1da177e4 | 508 | |
b6a2fea3 OW |
509 | /* |
510 | * ensure there are no vmas between where we want to go | |
511 | * and where we are | |
512 | */ | |
513 | if (vma != find_vma(mm, new_start)) | |
514 | return -EFAULT; | |
515 | ||
516 | /* | |
517 | * cover the whole range: [new_start, old_end) | |
518 | */ | |
519 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
520 | ||
521 | /* | |
522 | * move the page tables downwards, on failure we rely on | |
523 | * process cleanup to remove whatever mess we made. | |
524 | */ | |
525 | if (length != move_page_tables(vma, old_start, | |
526 | vma, new_start, length)) | |
527 | return -ENOMEM; | |
528 | ||
529 | lru_add_drain(); | |
530 | tlb = tlb_gather_mmu(mm, 0); | |
531 | if (new_end > old_start) { | |
532 | /* | |
533 | * when the old and new regions overlap clear from new_end. | |
534 | */ | |
535 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
536 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
537 | } else { | |
538 | /* | |
539 | * otherwise, clean from old_start; this is done to not touch | |
540 | * the address space in [new_end, old_start) some architectures | |
541 | * have constraints on va-space that make this illegal (IA64) - | |
542 | * for the others its just a little faster. | |
543 | */ | |
544 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
545 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
1da177e4 | 546 | } |
b6a2fea3 OW |
547 | tlb_finish_mmu(tlb, new_end, old_end); |
548 | ||
549 | /* | |
550 | * shrink the vma to just the new range. | |
551 | */ | |
552 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
553 | ||
554 | return 0; | |
1da177e4 LT |
555 | } |
556 | ||
557 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
558 | ||
b6a2fea3 OW |
559 | /* |
560 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
561 | * the stack is optionally relocated, and some extra space is added. | |
562 | */ | |
1da177e4 LT |
563 | int setup_arg_pages(struct linux_binprm *bprm, |
564 | unsigned long stack_top, | |
565 | int executable_stack) | |
566 | { | |
b6a2fea3 OW |
567 | unsigned long ret; |
568 | unsigned long stack_shift; | |
1da177e4 | 569 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
570 | struct vm_area_struct *vma = bprm->vma; |
571 | struct vm_area_struct *prev = NULL; | |
572 | unsigned long vm_flags; | |
573 | unsigned long stack_base; | |
1da177e4 LT |
574 | |
575 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
576 | /* Limit stack size to 1GB */ |
577 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
578 | if (stack_base > (1 << 30)) | |
579 | stack_base = 1 << 30; | |
1da177e4 | 580 | |
b6a2fea3 OW |
581 | /* Make sure we didn't let the argument array grow too large. */ |
582 | if (vma->vm_end - vma->vm_start > stack_base) | |
583 | return -ENOMEM; | |
1da177e4 | 584 | |
b6a2fea3 | 585 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 586 | |
b6a2fea3 OW |
587 | stack_shift = vma->vm_start - stack_base; |
588 | mm->arg_start = bprm->p - stack_shift; | |
589 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 590 | #else |
b6a2fea3 OW |
591 | stack_top = arch_align_stack(stack_top); |
592 | stack_top = PAGE_ALIGN(stack_top); | |
593 | stack_shift = vma->vm_end - stack_top; | |
594 | ||
595 | bprm->p -= stack_shift; | |
1da177e4 | 596 | mm->arg_start = bprm->p; |
1da177e4 LT |
597 | #endif |
598 | ||
1da177e4 | 599 | if (bprm->loader) |
b6a2fea3 OW |
600 | bprm->loader -= stack_shift; |
601 | bprm->exec -= stack_shift; | |
1da177e4 | 602 | |
1da177e4 | 603 | down_write(&mm->mmap_sem); |
b6a2fea3 OW |
604 | vm_flags = vma->vm_flags; |
605 | ||
606 | /* | |
607 | * Adjust stack execute permissions; explicitly enable for | |
608 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
609 | * (arch default) otherwise. | |
610 | */ | |
611 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
612 | vm_flags |= VM_EXEC; | |
613 | else if (executable_stack == EXSTACK_DISABLE_X) | |
614 | vm_flags &= ~VM_EXEC; | |
615 | vm_flags |= mm->def_flags; | |
616 | ||
617 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
618 | vm_flags); | |
619 | if (ret) | |
620 | goto out_unlock; | |
621 | BUG_ON(prev != vma); | |
622 | ||
623 | /* Move stack pages down in memory. */ | |
624 | if (stack_shift) { | |
625 | ret = shift_arg_pages(vma, stack_shift); | |
626 | if (ret) { | |
1da177e4 | 627 | up_write(&mm->mmap_sem); |
1da177e4 LT |
628 | return ret; |
629 | } | |
1da177e4 LT |
630 | } |
631 | ||
b6a2fea3 OW |
632 | #ifdef CONFIG_STACK_GROWSUP |
633 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
634 | #else | |
635 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
636 | #endif | |
637 | ret = expand_stack(vma, stack_base); | |
638 | if (ret) | |
639 | ret = -EFAULT; | |
640 | ||
641 | out_unlock: | |
1da177e4 | 642 | up_write(&mm->mmap_sem); |
1da177e4 LT |
643 | return 0; |
644 | } | |
1da177e4 LT |
645 | EXPORT_SYMBOL(setup_arg_pages); |
646 | ||
1da177e4 LT |
647 | #endif /* CONFIG_MMU */ |
648 | ||
649 | struct file *open_exec(const char *name) | |
650 | { | |
651 | struct nameidata nd; | |
652 | int err; | |
653 | struct file *file; | |
654 | ||
b500531e | 655 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
656 | file = ERR_PTR(err); |
657 | ||
658 | if (!err) { | |
659 | struct inode *inode = nd.dentry->d_inode; | |
660 | file = ERR_PTR(-EACCES); | |
661 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && | |
662 | S_ISREG(inode->i_mode)) { | |
e4543edd | 663 | int err = vfs_permission(&nd, MAY_EXEC); |
1da177e4 LT |
664 | file = ERR_PTR(err); |
665 | if (!err) { | |
834f2a4a | 666 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
667 | if (!IS_ERR(file)) { |
668 | err = deny_write_access(file); | |
669 | if (err) { | |
670 | fput(file); | |
671 | file = ERR_PTR(err); | |
672 | } | |
673 | } | |
674 | out: | |
675 | return file; | |
676 | } | |
677 | } | |
834f2a4a | 678 | release_open_intent(&nd); |
1da177e4 LT |
679 | path_release(&nd); |
680 | } | |
681 | goto out; | |
682 | } | |
683 | ||
684 | EXPORT_SYMBOL(open_exec); | |
685 | ||
686 | int kernel_read(struct file *file, unsigned long offset, | |
687 | char *addr, unsigned long count) | |
688 | { | |
689 | mm_segment_t old_fs; | |
690 | loff_t pos = offset; | |
691 | int result; | |
692 | ||
693 | old_fs = get_fs(); | |
694 | set_fs(get_ds()); | |
695 | /* The cast to a user pointer is valid due to the set_fs() */ | |
696 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
697 | set_fs(old_fs); | |
698 | return result; | |
699 | } | |
700 | ||
701 | EXPORT_SYMBOL(kernel_read); | |
702 | ||
703 | static int exec_mmap(struct mm_struct *mm) | |
704 | { | |
705 | struct task_struct *tsk; | |
706 | struct mm_struct * old_mm, *active_mm; | |
707 | ||
708 | /* Notify parent that we're no longer interested in the old VM */ | |
709 | tsk = current; | |
710 | old_mm = current->mm; | |
711 | mm_release(tsk, old_mm); | |
712 | ||
713 | if (old_mm) { | |
714 | /* | |
715 | * Make sure that if there is a core dump in progress | |
716 | * for the old mm, we get out and die instead of going | |
717 | * through with the exec. We must hold mmap_sem around | |
718 | * checking core_waiters and changing tsk->mm. The | |
719 | * core-inducing thread will increment core_waiters for | |
720 | * each thread whose ->mm == old_mm. | |
721 | */ | |
722 | down_read(&old_mm->mmap_sem); | |
723 | if (unlikely(old_mm->core_waiters)) { | |
724 | up_read(&old_mm->mmap_sem); | |
725 | return -EINTR; | |
726 | } | |
727 | } | |
728 | task_lock(tsk); | |
729 | active_mm = tsk->active_mm; | |
730 | tsk->mm = mm; | |
731 | tsk->active_mm = mm; | |
732 | activate_mm(active_mm, mm); | |
733 | task_unlock(tsk); | |
734 | arch_pick_mmap_layout(mm); | |
735 | if (old_mm) { | |
736 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 737 | BUG_ON(active_mm != old_mm); |
1da177e4 LT |
738 | mmput(old_mm); |
739 | return 0; | |
740 | } | |
741 | mmdrop(active_mm); | |
742 | return 0; | |
743 | } | |
744 | ||
745 | /* | |
746 | * This function makes sure the current process has its own signal table, | |
747 | * so that flush_signal_handlers can later reset the handlers without | |
748 | * disturbing other processes. (Other processes might share the signal | |
749 | * table via the CLONE_SIGHAND option to clone().) | |
750 | */ | |
858119e1 | 751 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
752 | { |
753 | struct signal_struct *sig = tsk->signal; | |
754 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand; | |
755 | spinlock_t *lock = &oldsighand->siglock; | |
329f7dba | 756 | struct task_struct *leader = NULL; |
1da177e4 LT |
757 | int count; |
758 | ||
759 | /* | |
760 | * If we don't share sighandlers, then we aren't sharing anything | |
761 | * and we can just re-use it all. | |
762 | */ | |
763 | if (atomic_read(&oldsighand->count) <= 1) { | |
1da177e4 LT |
764 | exit_itimers(sig); |
765 | return 0; | |
766 | } | |
767 | ||
768 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
769 | if (!newsighand) | |
770 | return -ENOMEM; | |
771 | ||
aafe6c2a | 772 | if (thread_group_empty(tsk)) |
1da177e4 LT |
773 | goto no_thread_group; |
774 | ||
775 | /* | |
776 | * Kill all other threads in the thread group. | |
777 | * We must hold tasklist_lock to call zap_other_threads. | |
778 | */ | |
779 | read_lock(&tasklist_lock); | |
780 | spin_lock_irq(lock); | |
781 | if (sig->flags & SIGNAL_GROUP_EXIT) { | |
782 | /* | |
783 | * Another group action in progress, just | |
784 | * return so that the signal is processed. | |
785 | */ | |
786 | spin_unlock_irq(lock); | |
787 | read_unlock(&tasklist_lock); | |
788 | kmem_cache_free(sighand_cachep, newsighand); | |
789 | return -EAGAIN; | |
790 | } | |
1434261c ON |
791 | |
792 | /* | |
793 | * child_reaper ignores SIGKILL, change it now. | |
794 | * Reparenting needs write_lock on tasklist_lock, | |
795 | * so it is safe to do it under read_lock. | |
796 | */ | |
84d73786 SB |
797 | if (unlikely(tsk->group_leader == child_reaper(tsk))) |
798 | tsk->nsproxy->pid_ns->child_reaper = tsk; | |
1434261c | 799 | |
aafe6c2a | 800 | zap_other_threads(tsk); |
1da177e4 LT |
801 | read_unlock(&tasklist_lock); |
802 | ||
803 | /* | |
804 | * Account for the thread group leader hanging around: | |
805 | */ | |
9e4e23bc | 806 | count = 1; |
aafe6c2a | 807 | if (!thread_group_leader(tsk)) { |
9e4e23bc | 808 | count = 2; |
53231250 RM |
809 | /* |
810 | * The SIGALRM timer survives the exec, but needs to point | |
811 | * at us as the new group leader now. We have a race with | |
812 | * a timer firing now getting the old leader, so we need to | |
813 | * synchronize with any firing (by calling del_timer_sync) | |
814 | * before we can safely let the old group leader die. | |
815 | */ | |
aafe6c2a | 816 | sig->tsk = tsk; |
932aeafb | 817 | spin_unlock_irq(lock); |
2ff678b8 TG |
818 | if (hrtimer_cancel(&sig->real_timer)) |
819 | hrtimer_restart(&sig->real_timer); | |
932aeafb | 820 | spin_lock_irq(lock); |
53231250 | 821 | } |
1da177e4 | 822 | while (atomic_read(&sig->count) > count) { |
aafe6c2a | 823 | sig->group_exit_task = tsk; |
1da177e4 LT |
824 | sig->notify_count = count; |
825 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
826 | spin_unlock_irq(lock); | |
827 | schedule(); | |
828 | spin_lock_irq(lock); | |
829 | } | |
830 | sig->group_exit_task = NULL; | |
831 | sig->notify_count = 0; | |
832 | spin_unlock_irq(lock); | |
833 | ||
834 | /* | |
835 | * At this point all other threads have exited, all we have to | |
836 | * do is to wait for the thread group leader to become inactive, | |
837 | * and to assume its PID: | |
838 | */ | |
aafe6c2a | 839 | if (!thread_group_leader(tsk)) { |
1da177e4 LT |
840 | /* |
841 | * Wait for the thread group leader to be a zombie. | |
842 | * It should already be zombie at this point, most | |
843 | * of the time. | |
844 | */ | |
aafe6c2a | 845 | leader = tsk->group_leader; |
1da177e4 LT |
846 | while (leader->exit_state != EXIT_ZOMBIE) |
847 | yield(); | |
848 | ||
f5e90281 RM |
849 | /* |
850 | * The only record we have of the real-time age of a | |
851 | * process, regardless of execs it's done, is start_time. | |
852 | * All the past CPU time is accumulated in signal_struct | |
853 | * from sister threads now dead. But in this non-leader | |
854 | * exec, nothing survives from the original leader thread, | |
855 | * whose birth marks the true age of this process now. | |
856 | * When we take on its identity by switching to its PID, we | |
857 | * also take its birthdate (always earlier than our own). | |
858 | */ | |
aafe6c2a | 859 | tsk->start_time = leader->start_time; |
f5e90281 | 860 | |
1da177e4 LT |
861 | write_lock_irq(&tasklist_lock); |
862 | ||
aafe6c2a EB |
863 | BUG_ON(leader->tgid != tsk->tgid); |
864 | BUG_ON(tsk->pid == tsk->tgid); | |
1da177e4 LT |
865 | /* |
866 | * An exec() starts a new thread group with the | |
867 | * TGID of the previous thread group. Rehash the | |
868 | * two threads with a switched PID, and release | |
869 | * the former thread group leader: | |
870 | */ | |
d73d6529 EB |
871 | |
872 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
873 | * The old leader becomes a thread of the this thread group. |
874 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
875 | * is called. Odd but simple and correct. |
876 | */ | |
aafe6c2a EB |
877 | detach_pid(tsk, PIDTYPE_PID); |
878 | tsk->pid = leader->pid; | |
e713d0da | 879 | attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid)); |
aafe6c2a EB |
880 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
881 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
882 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 883 | |
aafe6c2a EB |
884 | tsk->group_leader = tsk; |
885 | leader->group_leader = tsk; | |
de12a787 | 886 | |
aafe6c2a | 887 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
888 | |
889 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
890 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
891 | |
892 | write_unlock_irq(&tasklist_lock); | |
1da177e4 LT |
893 | } |
894 | ||
895 | /* | |
fb085cf1 AN |
896 | * There may be one thread left which is just exiting, |
897 | * but it's safe to stop telling the group to kill themselves. | |
1da177e4 LT |
898 | */ |
899 | sig->flags = 0; | |
900 | ||
901 | no_thread_group: | |
1da177e4 | 902 | exit_itimers(sig); |
329f7dba ON |
903 | if (leader) |
904 | release_task(leader); | |
905 | ||
1da177e4 LT |
906 | if (atomic_read(&oldsighand->count) == 1) { |
907 | /* | |
908 | * Now that we nuked the rest of the thread group, | |
909 | * it turns out we are not sharing sighand any more either. | |
910 | * So we can just keep it. | |
911 | */ | |
912 | kmem_cache_free(sighand_cachep, newsighand); | |
913 | } else { | |
914 | /* | |
915 | * Move our state over to newsighand and switch it in. | |
916 | */ | |
1da177e4 LT |
917 | atomic_set(&newsighand->count, 1); |
918 | memcpy(newsighand->action, oldsighand->action, | |
919 | sizeof(newsighand->action)); | |
920 | ||
921 | write_lock_irq(&tasklist_lock); | |
922 | spin_lock(&oldsighand->siglock); | |
513627d7 | 923 | spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING); |
1da177e4 | 924 | |
aafe6c2a | 925 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
926 | recalc_sigpending(); |
927 | ||
928 | spin_unlock(&newsighand->siglock); | |
929 | spin_unlock(&oldsighand->siglock); | |
930 | write_unlock_irq(&tasklist_lock); | |
931 | ||
fba2afaa | 932 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
933 | } |
934 | ||
aafe6c2a | 935 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
936 | return 0; |
937 | } | |
938 | ||
939 | /* | |
940 | * These functions flushes out all traces of the currently running executable | |
941 | * so that a new one can be started | |
942 | */ | |
943 | ||
858119e1 | 944 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
945 | { |
946 | long j = -1; | |
badf1662 | 947 | struct fdtable *fdt; |
1da177e4 LT |
948 | |
949 | spin_lock(&files->file_lock); | |
950 | for (;;) { | |
951 | unsigned long set, i; | |
952 | ||
953 | j++; | |
954 | i = j * __NFDBITS; | |
badf1662 | 955 | fdt = files_fdtable(files); |
bbea9f69 | 956 | if (i >= fdt->max_fds) |
1da177e4 | 957 | break; |
badf1662 | 958 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
959 | if (!set) |
960 | continue; | |
badf1662 | 961 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
962 | spin_unlock(&files->file_lock); |
963 | for ( ; set ; i++,set >>= 1) { | |
964 | if (set & 1) { | |
965 | sys_close(i); | |
966 | } | |
967 | } | |
968 | spin_lock(&files->file_lock); | |
969 | ||
970 | } | |
971 | spin_unlock(&files->file_lock); | |
972 | } | |
973 | ||
974 | void get_task_comm(char *buf, struct task_struct *tsk) | |
975 | { | |
976 | /* buf must be at least sizeof(tsk->comm) in size */ | |
977 | task_lock(tsk); | |
978 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
979 | task_unlock(tsk); | |
980 | } | |
981 | ||
982 | void set_task_comm(struct task_struct *tsk, char *buf) | |
983 | { | |
984 | task_lock(tsk); | |
985 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
986 | task_unlock(tsk); | |
987 | } | |
988 | ||
989 | int flush_old_exec(struct linux_binprm * bprm) | |
990 | { | |
991 | char * name; | |
992 | int i, ch, retval; | |
993 | struct files_struct *files; | |
994 | char tcomm[sizeof(current->comm)]; | |
995 | ||
996 | /* | |
997 | * Make sure we have a private signal table and that | |
998 | * we are unassociated from the previous thread group. | |
999 | */ | |
1000 | retval = de_thread(current); | |
1001 | if (retval) | |
1002 | goto out; | |
1003 | ||
1004 | /* | |
1005 | * Make sure we have private file handles. Ask the | |
1006 | * fork helper to do the work for us and the exit | |
1007 | * helper to do the cleanup of the old one. | |
1008 | */ | |
1009 | files = current->files; /* refcounted so safe to hold */ | |
1010 | retval = unshare_files(); | |
1011 | if (retval) | |
1012 | goto out; | |
1013 | /* | |
1014 | * Release all of the old mmap stuff | |
1015 | */ | |
1016 | retval = exec_mmap(bprm->mm); | |
1017 | if (retval) | |
1018 | goto mmap_failed; | |
1019 | ||
1020 | bprm->mm = NULL; /* We're using it now */ | |
1021 | ||
1022 | /* This is the point of no return */ | |
1da177e4 LT |
1023 | put_files_struct(files); |
1024 | ||
1025 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1026 | ||
1027 | if (current->euid == current->uid && current->egid == current->gid) | |
6c5d5238 | 1028 | set_dumpable(current->mm, 1); |
d6e71144 | 1029 | else |
6c5d5238 | 1030 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1031 | |
1da177e4 | 1032 | name = bprm->filename; |
36772092 PBG |
1033 | |
1034 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
1035 | for (i=0; (ch = *(name++)) != '\0';) { |
1036 | if (ch == '/') | |
36772092 | 1037 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
1038 | else |
1039 | if (i < (sizeof(tcomm) - 1)) | |
1040 | tcomm[i++] = ch; | |
1041 | } | |
1042 | tcomm[i] = '\0'; | |
1043 | set_task_comm(current, tcomm); | |
1044 | ||
1045 | current->flags &= ~PF_RANDOMIZE; | |
1046 | flush_thread(); | |
1047 | ||
0551fbd2 BH |
1048 | /* Set the new mm task size. We have to do that late because it may |
1049 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1050 | * some architectures like powerpc | |
1051 | */ | |
1052 | current->mm->task_size = TASK_SIZE; | |
1053 | ||
d2d56c5f MH |
1054 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { |
1055 | suid_keys(current); | |
1056 | set_dumpable(current->mm, suid_dumpable); | |
1057 | current->pdeath_signal = 0; | |
1058 | } else if (file_permission(bprm->file, MAY_READ) || | |
1059 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
1da177e4 | 1060 | suid_keys(current); |
6c5d5238 | 1061 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1062 | } |
1063 | ||
1064 | /* An exec changes our domain. We are no longer part of the thread | |
1065 | group */ | |
1066 | ||
1067 | current->self_exec_id++; | |
1068 | ||
1069 | flush_signal_handlers(current, 0); | |
1070 | flush_old_files(current->files); | |
1071 | ||
1072 | return 0; | |
1073 | ||
1074 | mmap_failed: | |
3b9b8ab6 | 1075 | reset_files_struct(current, files); |
1da177e4 LT |
1076 | out: |
1077 | return retval; | |
1078 | } | |
1079 | ||
1080 | EXPORT_SYMBOL(flush_old_exec); | |
1081 | ||
1082 | /* | |
1083 | * Fill the binprm structure from the inode. | |
1084 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1085 | */ | |
1086 | int prepare_binprm(struct linux_binprm *bprm) | |
1087 | { | |
1088 | int mode; | |
0f7fc9e4 | 1089 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1090 | int retval; |
1091 | ||
1092 | mode = inode->i_mode; | |
1da177e4 LT |
1093 | if (bprm->file->f_op == NULL) |
1094 | return -EACCES; | |
1095 | ||
1096 | bprm->e_uid = current->euid; | |
1097 | bprm->e_gid = current->egid; | |
1098 | ||
0f7fc9e4 | 1099 | if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1100 | /* Set-uid? */ |
1101 | if (mode & S_ISUID) { | |
1102 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1103 | bprm->e_uid = inode->i_uid; | |
1104 | } | |
1105 | ||
1106 | /* Set-gid? */ | |
1107 | /* | |
1108 | * If setgid is set but no group execute bit then this | |
1109 | * is a candidate for mandatory locking, not a setgid | |
1110 | * executable. | |
1111 | */ | |
1112 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1113 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1114 | bprm->e_gid = inode->i_gid; | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | /* fill in binprm security blob */ | |
1119 | retval = security_bprm_set(bprm); | |
1120 | if (retval) | |
1121 | return retval; | |
1122 | ||
1123 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
1124 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
1125 | } | |
1126 | ||
1127 | EXPORT_SYMBOL(prepare_binprm); | |
1128 | ||
858119e1 | 1129 | static int unsafe_exec(struct task_struct *p) |
1da177e4 LT |
1130 | { |
1131 | int unsafe = 0; | |
1132 | if (p->ptrace & PT_PTRACED) { | |
1133 | if (p->ptrace & PT_PTRACE_CAP) | |
1134 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1135 | else | |
1136 | unsafe |= LSM_UNSAFE_PTRACE; | |
1137 | } | |
1138 | if (atomic_read(&p->fs->count) > 1 || | |
1139 | atomic_read(&p->files->count) > 1 || | |
1140 | atomic_read(&p->sighand->count) > 1) | |
1141 | unsafe |= LSM_UNSAFE_SHARE; | |
1142 | ||
1143 | return unsafe; | |
1144 | } | |
1145 | ||
1146 | void compute_creds(struct linux_binprm *bprm) | |
1147 | { | |
1148 | int unsafe; | |
1149 | ||
d2d56c5f | 1150 | if (bprm->e_uid != current->uid) { |
1da177e4 | 1151 | suid_keys(current); |
d2d56c5f MH |
1152 | current->pdeath_signal = 0; |
1153 | } | |
1da177e4 LT |
1154 | exec_keys(current); |
1155 | ||
1156 | task_lock(current); | |
1157 | unsafe = unsafe_exec(current); | |
1158 | security_bprm_apply_creds(bprm, unsafe); | |
1159 | task_unlock(current); | |
1160 | security_bprm_post_apply_creds(bprm); | |
1161 | } | |
1da177e4 LT |
1162 | EXPORT_SYMBOL(compute_creds); |
1163 | ||
4fc75ff4 NP |
1164 | /* |
1165 | * Arguments are '\0' separated strings found at the location bprm->p | |
1166 | * points to; chop off the first by relocating brpm->p to right after | |
1167 | * the first '\0' encountered. | |
1168 | */ | |
b6a2fea3 | 1169 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1170 | { |
b6a2fea3 OW |
1171 | int ret = 0; |
1172 | unsigned long offset; | |
1173 | char *kaddr; | |
1174 | struct page *page; | |
4fc75ff4 | 1175 | |
b6a2fea3 OW |
1176 | if (!bprm->argc) |
1177 | return 0; | |
1da177e4 | 1178 | |
b6a2fea3 OW |
1179 | do { |
1180 | offset = bprm->p & ~PAGE_MASK; | |
1181 | page = get_arg_page(bprm, bprm->p, 0); | |
1182 | if (!page) { | |
1183 | ret = -EFAULT; | |
1184 | goto out; | |
1185 | } | |
1186 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1187 | |
b6a2fea3 OW |
1188 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1189 | offset++, bprm->p++) | |
1190 | ; | |
4fc75ff4 | 1191 | |
b6a2fea3 OW |
1192 | kunmap_atomic(kaddr, KM_USER0); |
1193 | put_arg_page(page); | |
4fc75ff4 | 1194 | |
b6a2fea3 OW |
1195 | if (offset == PAGE_SIZE) |
1196 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1197 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1198 | |
b6a2fea3 OW |
1199 | bprm->p++; |
1200 | bprm->argc--; | |
1201 | ret = 0; | |
4fc75ff4 | 1202 | |
b6a2fea3 OW |
1203 | out: |
1204 | return ret; | |
1da177e4 | 1205 | } |
1da177e4 LT |
1206 | EXPORT_SYMBOL(remove_arg_zero); |
1207 | ||
1208 | /* | |
1209 | * cycle the list of binary formats handler, until one recognizes the image | |
1210 | */ | |
1211 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1212 | { | |
1213 | int try,retval; | |
1214 | struct linux_binfmt *fmt; | |
1215 | #ifdef __alpha__ | |
1216 | /* handle /sbin/loader.. */ | |
1217 | { | |
1218 | struct exec * eh = (struct exec *) bprm->buf; | |
1219 | ||
1220 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1221 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1222 | { | |
1223 | struct file * file; | |
1224 | unsigned long loader; | |
1225 | ||
1226 | allow_write_access(bprm->file); | |
1227 | fput(bprm->file); | |
1228 | bprm->file = NULL; | |
1229 | ||
b6a2fea3 | 1230 | loader = bprm->vma->vm_end - sizeof(void *); |
1da177e4 LT |
1231 | |
1232 | file = open_exec("/sbin/loader"); | |
1233 | retval = PTR_ERR(file); | |
1234 | if (IS_ERR(file)) | |
1235 | return retval; | |
1236 | ||
1237 | /* Remember if the application is TASO. */ | |
1238 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1239 | ||
1240 | bprm->file = file; | |
1241 | bprm->loader = loader; | |
1242 | retval = prepare_binprm(bprm); | |
1243 | if (retval<0) | |
1244 | return retval; | |
1245 | /* should call search_binary_handler recursively here, | |
1246 | but it does not matter */ | |
1247 | } | |
1248 | } | |
1249 | #endif | |
1250 | retval = security_bprm_check(bprm); | |
1251 | if (retval) | |
1252 | return retval; | |
1253 | ||
1254 | /* kernel module loader fixup */ | |
1255 | /* so we don't try to load run modprobe in kernel space. */ | |
1256 | set_fs(USER_DS); | |
473ae30b AV |
1257 | |
1258 | retval = audit_bprm(bprm); | |
1259 | if (retval) | |
1260 | return retval; | |
1261 | ||
1da177e4 LT |
1262 | retval = -ENOENT; |
1263 | for (try=0; try<2; try++) { | |
1264 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1265 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1266 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1267 | if (!fn) | |
1268 | continue; | |
1269 | if (!try_module_get(fmt->module)) | |
1270 | continue; | |
1271 | read_unlock(&binfmt_lock); | |
1272 | retval = fn(bprm, regs); | |
1273 | if (retval >= 0) { | |
1274 | put_binfmt(fmt); | |
1275 | allow_write_access(bprm->file); | |
1276 | if (bprm->file) | |
1277 | fput(bprm->file); | |
1278 | bprm->file = NULL; | |
1279 | current->did_exec = 1; | |
9f46080c | 1280 | proc_exec_connector(current); |
1da177e4 LT |
1281 | return retval; |
1282 | } | |
1283 | read_lock(&binfmt_lock); | |
1284 | put_binfmt(fmt); | |
1285 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1286 | break; | |
1287 | if (!bprm->file) { | |
1288 | read_unlock(&binfmt_lock); | |
1289 | return retval; | |
1290 | } | |
1291 | } | |
1292 | read_unlock(&binfmt_lock); | |
1293 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1294 | break; | |
1295 | #ifdef CONFIG_KMOD | |
1296 | }else{ | |
1297 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1298 | if (printable(bprm->buf[0]) && | |
1299 | printable(bprm->buf[1]) && | |
1300 | printable(bprm->buf[2]) && | |
1301 | printable(bprm->buf[3])) | |
1302 | break; /* -ENOEXEC */ | |
1303 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1304 | #endif | |
1305 | } | |
1306 | } | |
1307 | return retval; | |
1308 | } | |
1309 | ||
1310 | EXPORT_SYMBOL(search_binary_handler); | |
1311 | ||
1312 | /* | |
1313 | * sys_execve() executes a new program. | |
1314 | */ | |
1315 | int do_execve(char * filename, | |
1316 | char __user *__user *argv, | |
1317 | char __user *__user *envp, | |
1318 | struct pt_regs * regs) | |
1319 | { | |
1320 | struct linux_binprm *bprm; | |
1321 | struct file *file; | |
bdf4c48a | 1322 | unsigned long env_p; |
1da177e4 | 1323 | int retval; |
1da177e4 LT |
1324 | |
1325 | retval = -ENOMEM; | |
11b0b5ab | 1326 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 LT |
1327 | if (!bprm) |
1328 | goto out_ret; | |
1da177e4 LT |
1329 | |
1330 | file = open_exec(filename); | |
1331 | retval = PTR_ERR(file); | |
1332 | if (IS_ERR(file)) | |
1333 | goto out_kfree; | |
1334 | ||
1335 | sched_exec(); | |
1336 | ||
1da177e4 LT |
1337 | bprm->file = file; |
1338 | bprm->filename = filename; | |
1339 | bprm->interp = filename; | |
1da177e4 | 1340 | |
b6a2fea3 OW |
1341 | retval = bprm_mm_init(bprm); |
1342 | if (retval) | |
1343 | goto out_file; | |
1da177e4 | 1344 | |
b6a2fea3 | 1345 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 LT |
1346 | if ((retval = bprm->argc) < 0) |
1347 | goto out_mm; | |
1348 | ||
b6a2fea3 | 1349 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 LT |
1350 | if ((retval = bprm->envc) < 0) |
1351 | goto out_mm; | |
1352 | ||
1353 | retval = security_bprm_alloc(bprm); | |
1354 | if (retval) | |
1355 | goto out; | |
1356 | ||
1357 | retval = prepare_binprm(bprm); | |
1358 | if (retval < 0) | |
1359 | goto out; | |
1360 | ||
1361 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1362 | if (retval < 0) | |
1363 | goto out; | |
1364 | ||
1365 | bprm->exec = bprm->p; | |
1366 | retval = copy_strings(bprm->envc, envp, bprm); | |
1367 | if (retval < 0) | |
1368 | goto out; | |
1369 | ||
bdf4c48a | 1370 | env_p = bprm->p; |
1da177e4 LT |
1371 | retval = copy_strings(bprm->argc, argv, bprm); |
1372 | if (retval < 0) | |
1373 | goto out; | |
bdf4c48a | 1374 | bprm->argv_len = env_p - bprm->p; |
1da177e4 LT |
1375 | |
1376 | retval = search_binary_handler(bprm,regs); | |
1377 | if (retval >= 0) { | |
1da177e4 | 1378 | /* execve success */ |
b6a2fea3 | 1379 | free_arg_pages(bprm); |
1da177e4 LT |
1380 | security_bprm_free(bprm); |
1381 | acct_update_integrals(current); | |
1da177e4 LT |
1382 | kfree(bprm); |
1383 | return retval; | |
1384 | } | |
1385 | ||
1386 | out: | |
b6a2fea3 | 1387 | free_arg_pages(bprm); |
1da177e4 LT |
1388 | if (bprm->security) |
1389 | security_bprm_free(bprm); | |
1390 | ||
1391 | out_mm: | |
1392 | if (bprm->mm) | |
b6a2fea3 | 1393 | mmput (bprm->mm); |
1da177e4 LT |
1394 | |
1395 | out_file: | |
1396 | if (bprm->file) { | |
1397 | allow_write_access(bprm->file); | |
1398 | fput(bprm->file); | |
1399 | } | |
1da177e4 LT |
1400 | out_kfree: |
1401 | kfree(bprm); | |
1402 | ||
1403 | out_ret: | |
1404 | return retval; | |
1405 | } | |
1406 | ||
1407 | int set_binfmt(struct linux_binfmt *new) | |
1408 | { | |
1409 | struct linux_binfmt *old = current->binfmt; | |
1410 | ||
1411 | if (new) { | |
1412 | if (!try_module_get(new->module)) | |
1413 | return -1; | |
1414 | } | |
1415 | current->binfmt = new; | |
1416 | if (old) | |
1417 | module_put(old->module); | |
1418 | return 0; | |
1419 | } | |
1420 | ||
1421 | EXPORT_SYMBOL(set_binfmt); | |
1422 | ||
1da177e4 LT |
1423 | /* format_corename will inspect the pattern parameter, and output a |
1424 | * name into corename, which must have space for at least | |
1425 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1426 | */ | |
c4bbafda | 1427 | static int format_corename(char *corename, const char *pattern, long signr) |
1da177e4 LT |
1428 | { |
1429 | const char *pat_ptr = pattern; | |
1430 | char *out_ptr = corename; | |
1431 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1432 | int rc; | |
1433 | int pid_in_pattern = 0; | |
c4bbafda AC |
1434 | int ispipe = 0; |
1435 | ||
1436 | if (*pattern == '|') | |
1437 | ispipe = 1; | |
1da177e4 LT |
1438 | |
1439 | /* Repeat as long as we have more pattern to process and more output | |
1440 | space */ | |
1441 | while (*pat_ptr) { | |
1442 | if (*pat_ptr != '%') { | |
1443 | if (out_ptr == out_end) | |
1444 | goto out; | |
1445 | *out_ptr++ = *pat_ptr++; | |
1446 | } else { | |
1447 | switch (*++pat_ptr) { | |
1448 | case 0: | |
1449 | goto out; | |
1450 | /* Double percent, output one percent */ | |
1451 | case '%': | |
1452 | if (out_ptr == out_end) | |
1453 | goto out; | |
1454 | *out_ptr++ = '%'; | |
1455 | break; | |
1456 | /* pid */ | |
1457 | case 'p': | |
1458 | pid_in_pattern = 1; | |
1459 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1460 | "%d", current->tgid); | |
1461 | if (rc > out_end - out_ptr) | |
1462 | goto out; | |
1463 | out_ptr += rc; | |
1464 | break; | |
1465 | /* uid */ | |
1466 | case 'u': | |
1467 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1468 | "%d", current->uid); | |
1469 | if (rc > out_end - out_ptr) | |
1470 | goto out; | |
1471 | out_ptr += rc; | |
1472 | break; | |
1473 | /* gid */ | |
1474 | case 'g': | |
1475 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1476 | "%d", current->gid); | |
1477 | if (rc > out_end - out_ptr) | |
1478 | goto out; | |
1479 | out_ptr += rc; | |
1480 | break; | |
1481 | /* signal that caused the coredump */ | |
1482 | case 's': | |
1483 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1484 | "%ld", signr); | |
1485 | if (rc > out_end - out_ptr) | |
1486 | goto out; | |
1487 | out_ptr += rc; | |
1488 | break; | |
1489 | /* UNIX time of coredump */ | |
1490 | case 't': { | |
1491 | struct timeval tv; | |
1492 | do_gettimeofday(&tv); | |
1493 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1494 | "%lu", tv.tv_sec); | |
1495 | if (rc > out_end - out_ptr) | |
1496 | goto out; | |
1497 | out_ptr += rc; | |
1498 | break; | |
1499 | } | |
1500 | /* hostname */ | |
1501 | case 'h': | |
1502 | down_read(&uts_sem); | |
1503 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1504 | "%s", utsname()->nodename); |
1da177e4 LT |
1505 | up_read(&uts_sem); |
1506 | if (rc > out_end - out_ptr) | |
1507 | goto out; | |
1508 | out_ptr += rc; | |
1509 | break; | |
1510 | /* executable */ | |
1511 | case 'e': | |
1512 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1513 | "%s", current->comm); | |
1514 | if (rc > out_end - out_ptr) | |
1515 | goto out; | |
1516 | out_ptr += rc; | |
1517 | break; | |
1518 | default: | |
1519 | break; | |
1520 | } | |
1521 | ++pat_ptr; | |
1522 | } | |
1523 | } | |
1524 | /* Backward compatibility with core_uses_pid: | |
1525 | * | |
1526 | * If core_pattern does not include a %p (as is the default) | |
1527 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda AC |
1528 | * the filename. Do not do this for piped commands. */ |
1529 | if (!ispipe && !pid_in_pattern | |
1da177e4 LT |
1530 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { |
1531 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1532 | ".%d", current->tgid); | |
1533 | if (rc > out_end - out_ptr) | |
1534 | goto out; | |
1535 | out_ptr += rc; | |
1536 | } | |
c4bbafda | 1537 | out: |
1da177e4 | 1538 | *out_ptr = 0; |
c4bbafda | 1539 | return ispipe; |
1da177e4 LT |
1540 | } |
1541 | ||
d5f70c00 | 1542 | static void zap_process(struct task_struct *start) |
aceecc04 ON |
1543 | { |
1544 | struct task_struct *t; | |
281de339 | 1545 | |
d5f70c00 ON |
1546 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1547 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1548 | |
1549 | t = start; | |
1550 | do { | |
1551 | if (t != current && t->mm) { | |
1552 | t->mm->core_waiters++; | |
281de339 ON |
1553 | sigaddset(&t->pending.signal, SIGKILL); |
1554 | signal_wake_up(t, 1); | |
aceecc04 ON |
1555 | } |
1556 | } while ((t = next_thread(t)) != start); | |
1557 | } | |
1558 | ||
dcf560c5 ON |
1559 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
1560 | int exit_code) | |
1da177e4 LT |
1561 | { |
1562 | struct task_struct *g, *p; | |
5debfa6d | 1563 | unsigned long flags; |
dcf560c5 ON |
1564 | int err = -EAGAIN; |
1565 | ||
1566 | spin_lock_irq(&tsk->sighand->siglock); | |
1567 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) { | |
dcf560c5 | 1568 | tsk->signal->group_exit_code = exit_code; |
5debfa6d | 1569 | zap_process(tsk); |
dcf560c5 | 1570 | err = 0; |
1da177e4 | 1571 | } |
dcf560c5 ON |
1572 | spin_unlock_irq(&tsk->sighand->siglock); |
1573 | if (err) | |
1574 | return err; | |
1da177e4 | 1575 | |
5debfa6d ON |
1576 | if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) |
1577 | goto done; | |
1578 | ||
7b1c6154 | 1579 | rcu_read_lock(); |
aceecc04 | 1580 | for_each_process(g) { |
5debfa6d ON |
1581 | if (g == tsk->group_leader) |
1582 | continue; | |
1583 | ||
aceecc04 ON |
1584 | p = g; |
1585 | do { | |
1586 | if (p->mm) { | |
5debfa6d ON |
1587 | if (p->mm == mm) { |
1588 | /* | |
1589 | * p->sighand can't disappear, but | |
1590 | * may be changed by de_thread() | |
1591 | */ | |
1592 | lock_task_sighand(p, &flags); | |
d5f70c00 | 1593 | zap_process(p); |
5debfa6d ON |
1594 | unlock_task_sighand(p, &flags); |
1595 | } | |
aceecc04 ON |
1596 | break; |
1597 | } | |
1598 | } while ((p = next_thread(p)) != g); | |
1599 | } | |
7b1c6154 | 1600 | rcu_read_unlock(); |
5debfa6d | 1601 | done: |
dcf560c5 | 1602 | return mm->core_waiters; |
1da177e4 LT |
1603 | } |
1604 | ||
dcf560c5 | 1605 | static int coredump_wait(int exit_code) |
1da177e4 | 1606 | { |
dcf560c5 ON |
1607 | struct task_struct *tsk = current; |
1608 | struct mm_struct *mm = tsk->mm; | |
1609 | struct completion startup_done; | |
1610 | struct completion *vfork_done; | |
2384f55f | 1611 | int core_waiters; |
1da177e4 | 1612 | |
dcf560c5 ON |
1613 | init_completion(&mm->core_done); |
1614 | init_completion(&startup_done); | |
1da177e4 LT |
1615 | mm->core_startup_done = &startup_done; |
1616 | ||
dcf560c5 | 1617 | core_waiters = zap_threads(tsk, mm, exit_code); |
2384f55f ON |
1618 | up_write(&mm->mmap_sem); |
1619 | ||
dcf560c5 ON |
1620 | if (unlikely(core_waiters < 0)) |
1621 | goto fail; | |
1622 | ||
1623 | /* | |
1624 | * Make sure nobody is waiting for us to release the VM, | |
1625 | * otherwise we can deadlock when we wait on each other | |
1626 | */ | |
1627 | vfork_done = tsk->vfork_done; | |
1628 | if (vfork_done) { | |
1629 | tsk->vfork_done = NULL; | |
1630 | complete(vfork_done); | |
1631 | } | |
1632 | ||
2384f55f | 1633 | if (core_waiters) |
1da177e4 | 1634 | wait_for_completion(&startup_done); |
dcf560c5 | 1635 | fail: |
1da177e4 | 1636 | BUG_ON(mm->core_waiters); |
dcf560c5 | 1637 | return core_waiters; |
1da177e4 LT |
1638 | } |
1639 | ||
6c5d5238 KH |
1640 | /* |
1641 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1642 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1643 | * these bits are not changed atomically. So get_dumpable can observe the | |
1644 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1645 | * return either old dumpable or new one by paying attention to the order of | |
1646 | * modifying the bits. | |
1647 | * | |
1648 | * dumpable | mm->flags (binary) | |
1649 | * old new | initial interim final | |
1650 | * ---------+----------------------- | |
1651 | * 0 1 | 00 01 01 | |
1652 | * 0 2 | 00 10(*) 11 | |
1653 | * 1 0 | 01 00 00 | |
1654 | * 1 2 | 01 11 11 | |
1655 | * 2 0 | 11 10(*) 00 | |
1656 | * 2 1 | 11 11 01 | |
1657 | * | |
1658 | * (*) get_dumpable regards interim value of 10 as 11. | |
1659 | */ | |
1660 | void set_dumpable(struct mm_struct *mm, int value) | |
1661 | { | |
1662 | switch (value) { | |
1663 | case 0: | |
1664 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1665 | smp_wmb(); | |
1666 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1667 | break; | |
1668 | case 1: | |
1669 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1670 | smp_wmb(); | |
1671 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1672 | break; | |
1673 | case 2: | |
1674 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1675 | smp_wmb(); | |
1676 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1677 | break; | |
1678 | } | |
1679 | } | |
1680 | EXPORT_SYMBOL_GPL(set_dumpable); | |
1681 | ||
1682 | int get_dumpable(struct mm_struct *mm) | |
1683 | { | |
1684 | int ret; | |
1685 | ||
1686 | ret = mm->flags & 0x3; | |
1687 | return (ret >= 2) ? 2 : ret; | |
1688 | } | |
1689 | ||
1da177e4 LT |
1690 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) |
1691 | { | |
1692 | char corename[CORENAME_MAX_SIZE + 1]; | |
1693 | struct mm_struct *mm = current->mm; | |
1694 | struct linux_binfmt * binfmt; | |
1695 | struct inode * inode; | |
1696 | struct file * file; | |
1697 | int retval = 0; | |
d6e71144 AC |
1698 | int fsuid = current->fsuid; |
1699 | int flag = 0; | |
d025c9db | 1700 | int ispipe = 0; |
1da177e4 | 1701 | |
0a4ff8c2 SG |
1702 | audit_core_dumps(signr); |
1703 | ||
1da177e4 LT |
1704 | binfmt = current->binfmt; |
1705 | if (!binfmt || !binfmt->core_dump) | |
1706 | goto fail; | |
1707 | down_write(&mm->mmap_sem); | |
6c5d5238 | 1708 | if (!get_dumpable(mm)) { |
1da177e4 LT |
1709 | up_write(&mm->mmap_sem); |
1710 | goto fail; | |
1711 | } | |
d6e71144 AC |
1712 | |
1713 | /* | |
1714 | * We cannot trust fsuid as being the "true" uid of the | |
1715 | * process nor do we know its entire history. We only know it | |
1716 | * was tainted so we dump it as root in mode 2. | |
1717 | */ | |
6c5d5238 | 1718 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 AC |
1719 | flag = O_EXCL; /* Stop rewrite attacks */ |
1720 | current->fsuid = 0; /* Dump root private */ | |
1721 | } | |
6c5d5238 | 1722 | set_dumpable(mm, 0); |
1291cf41 | 1723 | |
dcf560c5 ON |
1724 | retval = coredump_wait(exit_code); |
1725 | if (retval < 0) | |
1291cf41 | 1726 | goto fail; |
1da177e4 LT |
1727 | |
1728 | /* | |
1729 | * Clear any false indication of pending signals that might | |
1730 | * be seen by the filesystem code called to write the core file. | |
1731 | */ | |
1da177e4 LT |
1732 | clear_thread_flag(TIF_SIGPENDING); |
1733 | ||
1734 | if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) | |
1735 | goto fail_unlock; | |
1736 | ||
1737 | /* | |
1738 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1739 | * uses lock_kernel() | |
1740 | */ | |
1741 | lock_kernel(); | |
c4bbafda | 1742 | ispipe = format_corename(corename, core_pattern, signr); |
1da177e4 | 1743 | unlock_kernel(); |
c4bbafda | 1744 | if (ispipe) { |
d025c9db AK |
1745 | /* SIGPIPE can happen, but it's just never processed */ |
1746 | if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) { | |
1747 | printk(KERN_INFO "Core dump to %s pipe failed\n", | |
1748 | corename); | |
1749 | goto fail_unlock; | |
1750 | } | |
d025c9db AK |
1751 | } else |
1752 | file = filp_open(corename, | |
6d4df677 AD |
1753 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1754 | 0600); | |
1da177e4 LT |
1755 | if (IS_ERR(file)) |
1756 | goto fail_unlock; | |
0f7fc9e4 | 1757 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1758 | if (inode->i_nlink > 1) |
1759 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1760 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1761 | goto close_fail; |
1762 | ||
d025c9db AK |
1763 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1764 | but keep the previous behaviour for now. */ | |
1765 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 LT |
1766 | goto close_fail; |
1767 | if (!file->f_op) | |
1768 | goto close_fail; | |
1769 | if (!file->f_op->write) | |
1770 | goto close_fail; | |
0f7fc9e4 | 1771 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1772 | goto close_fail; |
1773 | ||
1774 | retval = binfmt->core_dump(signr, regs, file); | |
1775 | ||
1776 | if (retval) | |
1777 | current->signal->group_exit_code |= 0x80; | |
1778 | close_fail: | |
1779 | filp_close(file, NULL); | |
1780 | fail_unlock: | |
d6e71144 | 1781 | current->fsuid = fsuid; |
1da177e4 LT |
1782 | complete_all(&mm->core_done); |
1783 | fail: | |
1784 | return retval; | |
1785 | } |