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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 | ||
f6b450d4 | 84 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 85 | { |
1da177e4 | 86 | write_lock(&binfmt_lock); |
e4dc1b14 | 87 | list_del(&fmt->lh); |
1da177e4 | 88 | write_unlock(&binfmt_lock); |
1da177e4 LT |
89 | } |
90 | ||
91 | EXPORT_SYMBOL(unregister_binfmt); | |
92 | ||
93 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
94 | { | |
95 | module_put(fmt->module); | |
96 | } | |
97 | ||
98 | /* | |
99 | * Note that a shared library must be both readable and executable due to | |
100 | * security reasons. | |
101 | * | |
102 | * Also note that we take the address to load from from the file itself. | |
103 | */ | |
104 | asmlinkage long sys_uselib(const char __user * library) | |
105 | { | |
106 | struct file * file; | |
107 | struct nameidata nd; | |
108 | int error; | |
109 | ||
b500531e | 110 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
111 | if (error) |
112 | goto out; | |
113 | ||
492c8b33 CH |
114 | error = -EACCES; |
115 | if (nd.mnt->mnt_flags & MNT_NOEXEC) | |
116 | goto exit; | |
1da177e4 LT |
117 | error = -EINVAL; |
118 | if (!S_ISREG(nd.dentry->d_inode->i_mode)) | |
119 | goto exit; | |
120 | ||
e4543edd | 121 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC); |
1da177e4 LT |
122 | if (error) |
123 | goto exit; | |
124 | ||
834f2a4a | 125 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
126 | error = PTR_ERR(file); |
127 | if (IS_ERR(file)) | |
128 | goto out; | |
129 | ||
130 | error = -ENOEXEC; | |
131 | if(file->f_op) { | |
132 | struct linux_binfmt * fmt; | |
133 | ||
134 | read_lock(&binfmt_lock); | |
e4dc1b14 | 135 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
136 | if (!fmt->load_shlib) |
137 | continue; | |
138 | if (!try_module_get(fmt->module)) | |
139 | continue; | |
140 | read_unlock(&binfmt_lock); | |
141 | error = fmt->load_shlib(file); | |
142 | read_lock(&binfmt_lock); | |
143 | put_binfmt(fmt); | |
144 | if (error != -ENOEXEC) | |
145 | break; | |
146 | } | |
147 | read_unlock(&binfmt_lock); | |
148 | } | |
149 | fput(file); | |
150 | out: | |
151 | return error; | |
152 | exit: | |
834f2a4a | 153 | release_open_intent(&nd); |
1da177e4 LT |
154 | path_release(&nd); |
155 | goto out; | |
156 | } | |
157 | ||
b6a2fea3 OW |
158 | #ifdef CONFIG_MMU |
159 | ||
160 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
161 | int write) | |
162 | { | |
163 | struct page *page; | |
164 | int ret; | |
165 | ||
166 | #ifdef CONFIG_STACK_GROWSUP | |
167 | if (write) { | |
168 | ret = expand_stack_downwards(bprm->vma, pos); | |
169 | if (ret < 0) | |
170 | return NULL; | |
171 | } | |
172 | #endif | |
173 | ret = get_user_pages(current, bprm->mm, pos, | |
174 | 1, write, 1, &page, NULL); | |
175 | if (ret <= 0) | |
176 | return NULL; | |
177 | ||
178 | if (write) { | |
179 | struct rlimit *rlim = current->signal->rlim; | |
180 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
181 | ||
182 | /* | |
183 | * Limit to 1/4-th the stack size for the argv+env strings. | |
184 | * This ensures that: | |
185 | * - the remaining binfmt code will not run out of stack space, | |
186 | * - the program will have a reasonable amount of stack left | |
187 | * to work from. | |
188 | */ | |
189 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { | |
190 | put_page(page); | |
191 | return NULL; | |
192 | } | |
193 | } | |
194 | ||
195 | return page; | |
196 | } | |
197 | ||
198 | static void put_arg_page(struct page *page) | |
199 | { | |
200 | put_page(page); | |
201 | } | |
202 | ||
203 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
204 | { | |
205 | } | |
206 | ||
207 | static void free_arg_pages(struct linux_binprm *bprm) | |
208 | { | |
209 | } | |
210 | ||
211 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
212 | struct page *page) | |
213 | { | |
214 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
215 | } | |
216 | ||
217 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
218 | { | |
219 | int err = -ENOMEM; | |
220 | struct vm_area_struct *vma = NULL; | |
221 | struct mm_struct *mm = bprm->mm; | |
222 | ||
223 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
224 | if (!vma) | |
225 | goto err; | |
226 | ||
227 | down_write(&mm->mmap_sem); | |
228 | vma->vm_mm = mm; | |
229 | ||
230 | /* | |
231 | * Place the stack at the largest stack address the architecture | |
232 | * supports. Later, we'll move this to an appropriate place. We don't | |
233 | * use STACK_TOP because that can depend on attributes which aren't | |
234 | * configured yet. | |
235 | */ | |
236 | vma->vm_end = STACK_TOP_MAX; | |
237 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
238 | ||
239 | vma->vm_flags = VM_STACK_FLAGS; | |
240 | vma->vm_page_prot = protection_map[vma->vm_flags & 0x7]; | |
241 | err = insert_vm_struct(mm, vma); | |
242 | if (err) { | |
243 | up_write(&mm->mmap_sem); | |
244 | goto err; | |
245 | } | |
246 | ||
247 | mm->stack_vm = mm->total_vm = 1; | |
248 | up_write(&mm->mmap_sem); | |
249 | ||
250 | bprm->p = vma->vm_end - sizeof(void *); | |
251 | ||
252 | return 0; | |
253 | ||
254 | err: | |
255 | if (vma) { | |
256 | bprm->vma = NULL; | |
257 | kmem_cache_free(vm_area_cachep, vma); | |
258 | } | |
259 | ||
260 | return err; | |
261 | } | |
262 | ||
263 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
264 | { | |
265 | return len <= MAX_ARG_STRLEN; | |
266 | } | |
267 | ||
268 | #else | |
269 | ||
270 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
271 | int write) | |
272 | { | |
273 | struct page *page; | |
274 | ||
275 | page = bprm->page[pos / PAGE_SIZE]; | |
276 | if (!page && write) { | |
277 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
278 | if (!page) | |
279 | return NULL; | |
280 | bprm->page[pos / PAGE_SIZE] = page; | |
281 | } | |
282 | ||
283 | return page; | |
284 | } | |
285 | ||
286 | static void put_arg_page(struct page *page) | |
287 | { | |
288 | } | |
289 | ||
290 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
291 | { | |
292 | if (bprm->page[i]) { | |
293 | __free_page(bprm->page[i]); | |
294 | bprm->page[i] = NULL; | |
295 | } | |
296 | } | |
297 | ||
298 | static void free_arg_pages(struct linux_binprm *bprm) | |
299 | { | |
300 | int i; | |
301 | ||
302 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
303 | free_arg_page(bprm, i); | |
304 | } | |
305 | ||
306 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
307 | struct page *page) | |
308 | { | |
309 | } | |
310 | ||
311 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
312 | { | |
313 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
314 | return 0; | |
315 | } | |
316 | ||
317 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
318 | { | |
319 | return len <= bprm->p; | |
320 | } | |
321 | ||
322 | #endif /* CONFIG_MMU */ | |
323 | ||
324 | /* | |
325 | * Create a new mm_struct and populate it with a temporary stack | |
326 | * vm_area_struct. We don't have enough context at this point to set the stack | |
327 | * flags, permissions, and offset, so we use temporary values. We'll update | |
328 | * them later in setup_arg_pages(). | |
329 | */ | |
330 | int bprm_mm_init(struct linux_binprm *bprm) | |
331 | { | |
332 | int err; | |
333 | struct mm_struct *mm = NULL; | |
334 | ||
335 | bprm->mm = mm = mm_alloc(); | |
336 | err = -ENOMEM; | |
337 | if (!mm) | |
338 | goto err; | |
339 | ||
340 | err = init_new_context(current, mm); | |
341 | if (err) | |
342 | goto err; | |
343 | ||
344 | err = __bprm_mm_init(bprm); | |
345 | if (err) | |
346 | goto err; | |
347 | ||
348 | return 0; | |
349 | ||
350 | err: | |
351 | if (mm) { | |
352 | bprm->mm = NULL; | |
353 | mmdrop(mm); | |
354 | } | |
355 | ||
356 | return err; | |
357 | } | |
358 | ||
1da177e4 LT |
359 | /* |
360 | * count() counts the number of strings in array ARGV. | |
361 | */ | |
362 | static int count(char __user * __user * argv, int max) | |
363 | { | |
364 | int i = 0; | |
365 | ||
366 | if (argv != NULL) { | |
367 | for (;;) { | |
368 | char __user * p; | |
369 | ||
370 | if (get_user(p, argv)) | |
371 | return -EFAULT; | |
372 | if (!p) | |
373 | break; | |
374 | argv++; | |
375 | if(++i > max) | |
376 | return -E2BIG; | |
377 | cond_resched(); | |
378 | } | |
379 | } | |
380 | return i; | |
381 | } | |
382 | ||
383 | /* | |
b6a2fea3 OW |
384 | * 'copy_strings()' copies argument/environment strings from the old |
385 | * processes's memory to the new process's stack. The call to get_user_pages() | |
386 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 387 | */ |
75c96f85 AB |
388 | static int copy_strings(int argc, char __user * __user * argv, |
389 | struct linux_binprm *bprm) | |
1da177e4 LT |
390 | { |
391 | struct page *kmapped_page = NULL; | |
392 | char *kaddr = NULL; | |
b6a2fea3 | 393 | unsigned long kpos = 0; |
1da177e4 LT |
394 | int ret; |
395 | ||
396 | while (argc-- > 0) { | |
397 | char __user *str; | |
398 | int len; | |
399 | unsigned long pos; | |
400 | ||
401 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 402 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
403 | ret = -EFAULT; |
404 | goto out; | |
405 | } | |
406 | ||
b6a2fea3 | 407 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
408 | ret = -E2BIG; |
409 | goto out; | |
410 | } | |
411 | ||
b6a2fea3 | 412 | /* We're going to work our way backwords. */ |
1da177e4 | 413 | pos = bprm->p; |
b6a2fea3 OW |
414 | str += len; |
415 | bprm->p -= len; | |
1da177e4 LT |
416 | |
417 | while (len > 0) { | |
1da177e4 | 418 | int offset, bytes_to_copy; |
1da177e4 LT |
419 | |
420 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
421 | if (offset == 0) |
422 | offset = PAGE_SIZE; | |
423 | ||
424 | bytes_to_copy = offset; | |
425 | if (bytes_to_copy > len) | |
426 | bytes_to_copy = len; | |
427 | ||
428 | offset -= bytes_to_copy; | |
429 | pos -= bytes_to_copy; | |
430 | str -= bytes_to_copy; | |
431 | len -= bytes_to_copy; | |
432 | ||
433 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
434 | struct page *page; | |
435 | ||
436 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 437 | if (!page) { |
b6a2fea3 | 438 | ret = -E2BIG; |
1da177e4 LT |
439 | goto out; |
440 | } | |
1da177e4 | 441 | |
b6a2fea3 OW |
442 | if (kmapped_page) { |
443 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 444 | kunmap(kmapped_page); |
b6a2fea3 OW |
445 | put_arg_page(kmapped_page); |
446 | } | |
1da177e4 LT |
447 | kmapped_page = page; |
448 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
449 | kpos = pos & PAGE_MASK; |
450 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 451 | } |
b6a2fea3 | 452 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
453 | ret = -EFAULT; |
454 | goto out; | |
455 | } | |
1da177e4 LT |
456 | } |
457 | } | |
458 | ret = 0; | |
459 | out: | |
b6a2fea3 OW |
460 | if (kmapped_page) { |
461 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 462 | kunmap(kmapped_page); |
b6a2fea3 OW |
463 | put_arg_page(kmapped_page); |
464 | } | |
1da177e4 LT |
465 | return ret; |
466 | } | |
467 | ||
468 | /* | |
469 | * Like copy_strings, but get argv and its values from kernel memory. | |
470 | */ | |
471 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
472 | { | |
473 | int r; | |
474 | mm_segment_t oldfs = get_fs(); | |
475 | set_fs(KERNEL_DS); | |
476 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
477 | set_fs(oldfs); | |
478 | return r; | |
479 | } | |
1da177e4 LT |
480 | EXPORT_SYMBOL(copy_strings_kernel); |
481 | ||
482 | #ifdef CONFIG_MMU | |
b6a2fea3 | 483 | |
1da177e4 | 484 | /* |
b6a2fea3 OW |
485 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
486 | * the binfmt code determines where the new stack should reside, we shift it to | |
487 | * its final location. The process proceeds as follows: | |
1da177e4 | 488 | * |
b6a2fea3 OW |
489 | * 1) Use shift to calculate the new vma endpoints. |
490 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
491 | * arguments passed to subsequent functions are consistent. | |
492 | * 3) Move vma's page tables to the new range. | |
493 | * 4) Free up any cleared pgd range. | |
494 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 495 | */ |
b6a2fea3 | 496 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
497 | { |
498 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
499 | unsigned long old_start = vma->vm_start; |
500 | unsigned long old_end = vma->vm_end; | |
501 | unsigned long length = old_end - old_start; | |
502 | unsigned long new_start = old_start - shift; | |
503 | unsigned long new_end = old_end - shift; | |
504 | struct mmu_gather *tlb; | |
1da177e4 | 505 | |
b6a2fea3 | 506 | BUG_ON(new_start > new_end); |
1da177e4 | 507 | |
b6a2fea3 OW |
508 | /* |
509 | * ensure there are no vmas between where we want to go | |
510 | * and where we are | |
511 | */ | |
512 | if (vma != find_vma(mm, new_start)) | |
513 | return -EFAULT; | |
514 | ||
515 | /* | |
516 | * cover the whole range: [new_start, old_end) | |
517 | */ | |
518 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
519 | ||
520 | /* | |
521 | * move the page tables downwards, on failure we rely on | |
522 | * process cleanup to remove whatever mess we made. | |
523 | */ | |
524 | if (length != move_page_tables(vma, old_start, | |
525 | vma, new_start, length)) | |
526 | return -ENOMEM; | |
527 | ||
528 | lru_add_drain(); | |
529 | tlb = tlb_gather_mmu(mm, 0); | |
530 | if (new_end > old_start) { | |
531 | /* | |
532 | * when the old and new regions overlap clear from new_end. | |
533 | */ | |
534 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
535 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
536 | } else { | |
537 | /* | |
538 | * otherwise, clean from old_start; this is done to not touch | |
539 | * the address space in [new_end, old_start) some architectures | |
540 | * have constraints on va-space that make this illegal (IA64) - | |
541 | * for the others its just a little faster. | |
542 | */ | |
543 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
544 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
1da177e4 | 545 | } |
b6a2fea3 OW |
546 | tlb_finish_mmu(tlb, new_end, old_end); |
547 | ||
548 | /* | |
549 | * shrink the vma to just the new range. | |
550 | */ | |
551 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
552 | ||
553 | return 0; | |
1da177e4 LT |
554 | } |
555 | ||
556 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
557 | ||
b6a2fea3 OW |
558 | /* |
559 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
560 | * the stack is optionally relocated, and some extra space is added. | |
561 | */ | |
1da177e4 LT |
562 | int setup_arg_pages(struct linux_binprm *bprm, |
563 | unsigned long stack_top, | |
564 | int executable_stack) | |
565 | { | |
b6a2fea3 OW |
566 | unsigned long ret; |
567 | unsigned long stack_shift; | |
1da177e4 | 568 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
569 | struct vm_area_struct *vma = bprm->vma; |
570 | struct vm_area_struct *prev = NULL; | |
571 | unsigned long vm_flags; | |
572 | unsigned long stack_base; | |
1da177e4 LT |
573 | |
574 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
575 | /* Limit stack size to 1GB */ |
576 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
577 | if (stack_base > (1 << 30)) | |
578 | stack_base = 1 << 30; | |
1da177e4 | 579 | |
b6a2fea3 OW |
580 | /* Make sure we didn't let the argument array grow too large. */ |
581 | if (vma->vm_end - vma->vm_start > stack_base) | |
582 | return -ENOMEM; | |
1da177e4 | 583 | |
b6a2fea3 | 584 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 585 | |
b6a2fea3 OW |
586 | stack_shift = vma->vm_start - stack_base; |
587 | mm->arg_start = bprm->p - stack_shift; | |
588 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 589 | #else |
b6a2fea3 OW |
590 | stack_top = arch_align_stack(stack_top); |
591 | stack_top = PAGE_ALIGN(stack_top); | |
592 | stack_shift = vma->vm_end - stack_top; | |
593 | ||
594 | bprm->p -= stack_shift; | |
1da177e4 | 595 | mm->arg_start = bprm->p; |
1da177e4 LT |
596 | #endif |
597 | ||
1da177e4 | 598 | if (bprm->loader) |
b6a2fea3 OW |
599 | bprm->loader -= stack_shift; |
600 | bprm->exec -= stack_shift; | |
1da177e4 | 601 | |
1da177e4 | 602 | down_write(&mm->mmap_sem); |
b6a2fea3 OW |
603 | vm_flags = vma->vm_flags; |
604 | ||
605 | /* | |
606 | * Adjust stack execute permissions; explicitly enable for | |
607 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
608 | * (arch default) otherwise. | |
609 | */ | |
610 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
611 | vm_flags |= VM_EXEC; | |
612 | else if (executable_stack == EXSTACK_DISABLE_X) | |
613 | vm_flags &= ~VM_EXEC; | |
614 | vm_flags |= mm->def_flags; | |
615 | ||
616 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
617 | vm_flags); | |
618 | if (ret) | |
619 | goto out_unlock; | |
620 | BUG_ON(prev != vma); | |
621 | ||
622 | /* Move stack pages down in memory. */ | |
623 | if (stack_shift) { | |
624 | ret = shift_arg_pages(vma, stack_shift); | |
625 | if (ret) { | |
1da177e4 | 626 | up_write(&mm->mmap_sem); |
1da177e4 LT |
627 | return ret; |
628 | } | |
1da177e4 LT |
629 | } |
630 | ||
b6a2fea3 OW |
631 | #ifdef CONFIG_STACK_GROWSUP |
632 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
633 | #else | |
634 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
635 | #endif | |
636 | ret = expand_stack(vma, stack_base); | |
637 | if (ret) | |
638 | ret = -EFAULT; | |
639 | ||
640 | out_unlock: | |
1da177e4 | 641 | up_write(&mm->mmap_sem); |
1da177e4 LT |
642 | return 0; |
643 | } | |
1da177e4 LT |
644 | EXPORT_SYMBOL(setup_arg_pages); |
645 | ||
1da177e4 LT |
646 | #endif /* CONFIG_MMU */ |
647 | ||
648 | struct file *open_exec(const char *name) | |
649 | { | |
650 | struct nameidata nd; | |
651 | int err; | |
652 | struct file *file; | |
653 | ||
b500531e | 654 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
655 | file = ERR_PTR(err); |
656 | ||
657 | if (!err) { | |
658 | struct inode *inode = nd.dentry->d_inode; | |
659 | file = ERR_PTR(-EACCES); | |
660 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && | |
661 | S_ISREG(inode->i_mode)) { | |
e4543edd | 662 | int err = vfs_permission(&nd, MAY_EXEC); |
1da177e4 LT |
663 | file = ERR_PTR(err); |
664 | if (!err) { | |
834f2a4a | 665 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
666 | if (!IS_ERR(file)) { |
667 | err = deny_write_access(file); | |
668 | if (err) { | |
669 | fput(file); | |
670 | file = ERR_PTR(err); | |
671 | } | |
672 | } | |
673 | out: | |
674 | return file; | |
675 | } | |
676 | } | |
834f2a4a | 677 | release_open_intent(&nd); |
1da177e4 LT |
678 | path_release(&nd); |
679 | } | |
680 | goto out; | |
681 | } | |
682 | ||
683 | EXPORT_SYMBOL(open_exec); | |
684 | ||
685 | int kernel_read(struct file *file, unsigned long offset, | |
686 | char *addr, unsigned long count) | |
687 | { | |
688 | mm_segment_t old_fs; | |
689 | loff_t pos = offset; | |
690 | int result; | |
691 | ||
692 | old_fs = get_fs(); | |
693 | set_fs(get_ds()); | |
694 | /* The cast to a user pointer is valid due to the set_fs() */ | |
695 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
696 | set_fs(old_fs); | |
697 | return result; | |
698 | } | |
699 | ||
700 | EXPORT_SYMBOL(kernel_read); | |
701 | ||
702 | static int exec_mmap(struct mm_struct *mm) | |
703 | { | |
704 | struct task_struct *tsk; | |
705 | struct mm_struct * old_mm, *active_mm; | |
706 | ||
707 | /* Notify parent that we're no longer interested in the old VM */ | |
708 | tsk = current; | |
709 | old_mm = current->mm; | |
710 | mm_release(tsk, old_mm); | |
711 | ||
712 | if (old_mm) { | |
713 | /* | |
714 | * Make sure that if there is a core dump in progress | |
715 | * for the old mm, we get out and die instead of going | |
716 | * through with the exec. We must hold mmap_sem around | |
717 | * checking core_waiters and changing tsk->mm. The | |
718 | * core-inducing thread will increment core_waiters for | |
719 | * each thread whose ->mm == old_mm. | |
720 | */ | |
721 | down_read(&old_mm->mmap_sem); | |
722 | if (unlikely(old_mm->core_waiters)) { | |
723 | up_read(&old_mm->mmap_sem); | |
724 | return -EINTR; | |
725 | } | |
726 | } | |
727 | task_lock(tsk); | |
728 | active_mm = tsk->active_mm; | |
729 | tsk->mm = mm; | |
730 | tsk->active_mm = mm; | |
731 | activate_mm(active_mm, mm); | |
732 | task_unlock(tsk); | |
733 | arch_pick_mmap_layout(mm); | |
734 | if (old_mm) { | |
735 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 736 | BUG_ON(active_mm != old_mm); |
1da177e4 LT |
737 | mmput(old_mm); |
738 | return 0; | |
739 | } | |
740 | mmdrop(active_mm); | |
741 | return 0; | |
742 | } | |
743 | ||
744 | /* | |
745 | * This function makes sure the current process has its own signal table, | |
746 | * so that flush_signal_handlers can later reset the handlers without | |
747 | * disturbing other processes. (Other processes might share the signal | |
748 | * table via the CLONE_SIGHAND option to clone().) | |
749 | */ | |
858119e1 | 750 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
751 | { |
752 | struct signal_struct *sig = tsk->signal; | |
753 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand; | |
754 | spinlock_t *lock = &oldsighand->siglock; | |
329f7dba | 755 | struct task_struct *leader = NULL; |
1da177e4 LT |
756 | int count; |
757 | ||
758 | /* | |
759 | * If we don't share sighandlers, then we aren't sharing anything | |
760 | * and we can just re-use it all. | |
761 | */ | |
762 | if (atomic_read(&oldsighand->count) <= 1) { | |
1da177e4 LT |
763 | exit_itimers(sig); |
764 | return 0; | |
765 | } | |
766 | ||
767 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
768 | if (!newsighand) | |
769 | return -ENOMEM; | |
770 | ||
aafe6c2a | 771 | if (thread_group_empty(tsk)) |
1da177e4 LT |
772 | goto no_thread_group; |
773 | ||
774 | /* | |
775 | * Kill all other threads in the thread group. | |
776 | * We must hold tasklist_lock to call zap_other_threads. | |
777 | */ | |
778 | read_lock(&tasklist_lock); | |
779 | spin_lock_irq(lock); | |
780 | if (sig->flags & SIGNAL_GROUP_EXIT) { | |
781 | /* | |
782 | * Another group action in progress, just | |
783 | * return so that the signal is processed. | |
784 | */ | |
785 | spin_unlock_irq(lock); | |
786 | read_unlock(&tasklist_lock); | |
787 | kmem_cache_free(sighand_cachep, newsighand); | |
788 | return -EAGAIN; | |
789 | } | |
1434261c ON |
790 | |
791 | /* | |
792 | * child_reaper ignores SIGKILL, change it now. | |
793 | * Reparenting needs write_lock on tasklist_lock, | |
794 | * so it is safe to do it under read_lock. | |
795 | */ | |
84d73786 SB |
796 | if (unlikely(tsk->group_leader == child_reaper(tsk))) |
797 | tsk->nsproxy->pid_ns->child_reaper = tsk; | |
1434261c | 798 | |
aafe6c2a | 799 | zap_other_threads(tsk); |
1da177e4 LT |
800 | read_unlock(&tasklist_lock); |
801 | ||
802 | /* | |
803 | * Account for the thread group leader hanging around: | |
804 | */ | |
9e4e23bc | 805 | count = 1; |
aafe6c2a | 806 | if (!thread_group_leader(tsk)) { |
9e4e23bc | 807 | count = 2; |
53231250 RM |
808 | /* |
809 | * The SIGALRM timer survives the exec, but needs to point | |
810 | * at us as the new group leader now. We have a race with | |
811 | * a timer firing now getting the old leader, so we need to | |
812 | * synchronize with any firing (by calling del_timer_sync) | |
813 | * before we can safely let the old group leader die. | |
814 | */ | |
aafe6c2a | 815 | sig->tsk = tsk; |
932aeafb | 816 | spin_unlock_irq(lock); |
2ff678b8 TG |
817 | if (hrtimer_cancel(&sig->real_timer)) |
818 | hrtimer_restart(&sig->real_timer); | |
932aeafb | 819 | spin_lock_irq(lock); |
53231250 | 820 | } |
1da177e4 | 821 | while (atomic_read(&sig->count) > count) { |
aafe6c2a | 822 | sig->group_exit_task = tsk; |
1da177e4 LT |
823 | sig->notify_count = count; |
824 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
825 | spin_unlock_irq(lock); | |
826 | schedule(); | |
827 | spin_lock_irq(lock); | |
828 | } | |
829 | sig->group_exit_task = NULL; | |
830 | sig->notify_count = 0; | |
831 | spin_unlock_irq(lock); | |
832 | ||
833 | /* | |
834 | * At this point all other threads have exited, all we have to | |
835 | * do is to wait for the thread group leader to become inactive, | |
836 | * and to assume its PID: | |
837 | */ | |
aafe6c2a | 838 | if (!thread_group_leader(tsk)) { |
1da177e4 LT |
839 | /* |
840 | * Wait for the thread group leader to be a zombie. | |
841 | * It should already be zombie at this point, most | |
842 | * of the time. | |
843 | */ | |
aafe6c2a | 844 | leader = tsk->group_leader; |
1da177e4 LT |
845 | while (leader->exit_state != EXIT_ZOMBIE) |
846 | yield(); | |
847 | ||
f5e90281 RM |
848 | /* |
849 | * The only record we have of the real-time age of a | |
850 | * process, regardless of execs it's done, is start_time. | |
851 | * All the past CPU time is accumulated in signal_struct | |
852 | * from sister threads now dead. But in this non-leader | |
853 | * exec, nothing survives from the original leader thread, | |
854 | * whose birth marks the true age of this process now. | |
855 | * When we take on its identity by switching to its PID, we | |
856 | * also take its birthdate (always earlier than our own). | |
857 | */ | |
aafe6c2a | 858 | tsk->start_time = leader->start_time; |
f5e90281 | 859 | |
1da177e4 LT |
860 | write_lock_irq(&tasklist_lock); |
861 | ||
aafe6c2a EB |
862 | BUG_ON(leader->tgid != tsk->tgid); |
863 | BUG_ON(tsk->pid == tsk->tgid); | |
1da177e4 LT |
864 | /* |
865 | * An exec() starts a new thread group with the | |
866 | * TGID of the previous thread group. Rehash the | |
867 | * two threads with a switched PID, and release | |
868 | * the former thread group leader: | |
869 | */ | |
d73d6529 EB |
870 | |
871 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
872 | * The old leader becomes a thread of the this thread group. |
873 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
874 | * is called. Odd but simple and correct. |
875 | */ | |
aafe6c2a EB |
876 | detach_pid(tsk, PIDTYPE_PID); |
877 | tsk->pid = leader->pid; | |
e713d0da | 878 | attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid)); |
aafe6c2a EB |
879 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
880 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
881 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 882 | |
aafe6c2a EB |
883 | tsk->group_leader = tsk; |
884 | leader->group_leader = tsk; | |
de12a787 | 885 | |
aafe6c2a | 886 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
887 | |
888 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
889 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
890 | |
891 | write_unlock_irq(&tasklist_lock); | |
1da177e4 LT |
892 | } |
893 | ||
894 | /* | |
fb085cf1 AN |
895 | * There may be one thread left which is just exiting, |
896 | * but it's safe to stop telling the group to kill themselves. | |
1da177e4 LT |
897 | */ |
898 | sig->flags = 0; | |
899 | ||
900 | no_thread_group: | |
1da177e4 | 901 | exit_itimers(sig); |
329f7dba ON |
902 | if (leader) |
903 | release_task(leader); | |
904 | ||
1da177e4 LT |
905 | if (atomic_read(&oldsighand->count) == 1) { |
906 | /* | |
907 | * Now that we nuked the rest of the thread group, | |
908 | * it turns out we are not sharing sighand any more either. | |
909 | * So we can just keep it. | |
910 | */ | |
911 | kmem_cache_free(sighand_cachep, newsighand); | |
912 | } else { | |
913 | /* | |
914 | * Move our state over to newsighand and switch it in. | |
915 | */ | |
1da177e4 LT |
916 | atomic_set(&newsighand->count, 1); |
917 | memcpy(newsighand->action, oldsighand->action, | |
918 | sizeof(newsighand->action)); | |
919 | ||
920 | write_lock_irq(&tasklist_lock); | |
921 | spin_lock(&oldsighand->siglock); | |
513627d7 | 922 | spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING); |
1da177e4 | 923 | |
aafe6c2a | 924 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
925 | recalc_sigpending(); |
926 | ||
927 | spin_unlock(&newsighand->siglock); | |
928 | spin_unlock(&oldsighand->siglock); | |
929 | write_unlock_irq(&tasklist_lock); | |
930 | ||
fba2afaa | 931 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
932 | } |
933 | ||
aafe6c2a | 934 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
935 | return 0; |
936 | } | |
937 | ||
938 | /* | |
939 | * These functions flushes out all traces of the currently running executable | |
940 | * so that a new one can be started | |
941 | */ | |
942 | ||
858119e1 | 943 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
944 | { |
945 | long j = -1; | |
badf1662 | 946 | struct fdtable *fdt; |
1da177e4 LT |
947 | |
948 | spin_lock(&files->file_lock); | |
949 | for (;;) { | |
950 | unsigned long set, i; | |
951 | ||
952 | j++; | |
953 | i = j * __NFDBITS; | |
badf1662 | 954 | fdt = files_fdtable(files); |
bbea9f69 | 955 | if (i >= fdt->max_fds) |
1da177e4 | 956 | break; |
badf1662 | 957 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
958 | if (!set) |
959 | continue; | |
badf1662 | 960 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
961 | spin_unlock(&files->file_lock); |
962 | for ( ; set ; i++,set >>= 1) { | |
963 | if (set & 1) { | |
964 | sys_close(i); | |
965 | } | |
966 | } | |
967 | spin_lock(&files->file_lock); | |
968 | ||
969 | } | |
970 | spin_unlock(&files->file_lock); | |
971 | } | |
972 | ||
973 | void get_task_comm(char *buf, struct task_struct *tsk) | |
974 | { | |
975 | /* buf must be at least sizeof(tsk->comm) in size */ | |
976 | task_lock(tsk); | |
977 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
978 | task_unlock(tsk); | |
979 | } | |
980 | ||
981 | void set_task_comm(struct task_struct *tsk, char *buf) | |
982 | { | |
983 | task_lock(tsk); | |
984 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
985 | task_unlock(tsk); | |
986 | } | |
987 | ||
988 | int flush_old_exec(struct linux_binprm * bprm) | |
989 | { | |
990 | char * name; | |
991 | int i, ch, retval; | |
992 | struct files_struct *files; | |
993 | char tcomm[sizeof(current->comm)]; | |
994 | ||
995 | /* | |
996 | * Make sure we have a private signal table and that | |
997 | * we are unassociated from the previous thread group. | |
998 | */ | |
999 | retval = de_thread(current); | |
1000 | if (retval) | |
1001 | goto out; | |
1002 | ||
1003 | /* | |
1004 | * Make sure we have private file handles. Ask the | |
1005 | * fork helper to do the work for us and the exit | |
1006 | * helper to do the cleanup of the old one. | |
1007 | */ | |
1008 | files = current->files; /* refcounted so safe to hold */ | |
1009 | retval = unshare_files(); | |
1010 | if (retval) | |
1011 | goto out; | |
1012 | /* | |
1013 | * Release all of the old mmap stuff | |
1014 | */ | |
1015 | retval = exec_mmap(bprm->mm); | |
1016 | if (retval) | |
1017 | goto mmap_failed; | |
1018 | ||
1019 | bprm->mm = NULL; /* We're using it now */ | |
1020 | ||
1021 | /* This is the point of no return */ | |
1da177e4 LT |
1022 | put_files_struct(files); |
1023 | ||
1024 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1025 | ||
1026 | if (current->euid == current->uid && current->egid == current->gid) | |
6c5d5238 | 1027 | set_dumpable(current->mm, 1); |
d6e71144 | 1028 | else |
6c5d5238 | 1029 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1030 | |
1da177e4 | 1031 | name = bprm->filename; |
36772092 PBG |
1032 | |
1033 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
1034 | for (i=0; (ch = *(name++)) != '\0';) { |
1035 | if (ch == '/') | |
36772092 | 1036 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
1037 | else |
1038 | if (i < (sizeof(tcomm) - 1)) | |
1039 | tcomm[i++] = ch; | |
1040 | } | |
1041 | tcomm[i] = '\0'; | |
1042 | set_task_comm(current, tcomm); | |
1043 | ||
1044 | current->flags &= ~PF_RANDOMIZE; | |
1045 | flush_thread(); | |
1046 | ||
0551fbd2 BH |
1047 | /* Set the new mm task size. We have to do that late because it may |
1048 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1049 | * some architectures like powerpc | |
1050 | */ | |
1051 | current->mm->task_size = TASK_SIZE; | |
1052 | ||
d2d56c5f MH |
1053 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { |
1054 | suid_keys(current); | |
1055 | set_dumpable(current->mm, suid_dumpable); | |
1056 | current->pdeath_signal = 0; | |
1057 | } else if (file_permission(bprm->file, MAY_READ) || | |
1058 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
1da177e4 | 1059 | suid_keys(current); |
6c5d5238 | 1060 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1061 | } |
1062 | ||
1063 | /* An exec changes our domain. We are no longer part of the thread | |
1064 | group */ | |
1065 | ||
1066 | current->self_exec_id++; | |
1067 | ||
1068 | flush_signal_handlers(current, 0); | |
1069 | flush_old_files(current->files); | |
1070 | ||
1071 | return 0; | |
1072 | ||
1073 | mmap_failed: | |
3b9b8ab6 | 1074 | reset_files_struct(current, files); |
1da177e4 LT |
1075 | out: |
1076 | return retval; | |
1077 | } | |
1078 | ||
1079 | EXPORT_SYMBOL(flush_old_exec); | |
1080 | ||
1081 | /* | |
1082 | * Fill the binprm structure from the inode. | |
1083 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1084 | */ | |
1085 | int prepare_binprm(struct linux_binprm *bprm) | |
1086 | { | |
1087 | int mode; | |
0f7fc9e4 | 1088 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1089 | int retval; |
1090 | ||
1091 | mode = inode->i_mode; | |
1da177e4 LT |
1092 | if (bprm->file->f_op == NULL) |
1093 | return -EACCES; | |
1094 | ||
1095 | bprm->e_uid = current->euid; | |
1096 | bprm->e_gid = current->egid; | |
1097 | ||
0f7fc9e4 | 1098 | if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1099 | /* Set-uid? */ |
1100 | if (mode & S_ISUID) { | |
1101 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1102 | bprm->e_uid = inode->i_uid; | |
1103 | } | |
1104 | ||
1105 | /* Set-gid? */ | |
1106 | /* | |
1107 | * If setgid is set but no group execute bit then this | |
1108 | * is a candidate for mandatory locking, not a setgid | |
1109 | * executable. | |
1110 | */ | |
1111 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1112 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1113 | bprm->e_gid = inode->i_gid; | |
1114 | } | |
1115 | } | |
1116 | ||
1117 | /* fill in binprm security blob */ | |
1118 | retval = security_bprm_set(bprm); | |
1119 | if (retval) | |
1120 | return retval; | |
1121 | ||
1122 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
1123 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
1124 | } | |
1125 | ||
1126 | EXPORT_SYMBOL(prepare_binprm); | |
1127 | ||
858119e1 | 1128 | static int unsafe_exec(struct task_struct *p) |
1da177e4 LT |
1129 | { |
1130 | int unsafe = 0; | |
1131 | if (p->ptrace & PT_PTRACED) { | |
1132 | if (p->ptrace & PT_PTRACE_CAP) | |
1133 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1134 | else | |
1135 | unsafe |= LSM_UNSAFE_PTRACE; | |
1136 | } | |
1137 | if (atomic_read(&p->fs->count) > 1 || | |
1138 | atomic_read(&p->files->count) > 1 || | |
1139 | atomic_read(&p->sighand->count) > 1) | |
1140 | unsafe |= LSM_UNSAFE_SHARE; | |
1141 | ||
1142 | return unsafe; | |
1143 | } | |
1144 | ||
1145 | void compute_creds(struct linux_binprm *bprm) | |
1146 | { | |
1147 | int unsafe; | |
1148 | ||
d2d56c5f | 1149 | if (bprm->e_uid != current->uid) { |
1da177e4 | 1150 | suid_keys(current); |
d2d56c5f MH |
1151 | current->pdeath_signal = 0; |
1152 | } | |
1da177e4 LT |
1153 | exec_keys(current); |
1154 | ||
1155 | task_lock(current); | |
1156 | unsafe = unsafe_exec(current); | |
1157 | security_bprm_apply_creds(bprm, unsafe); | |
1158 | task_unlock(current); | |
1159 | security_bprm_post_apply_creds(bprm); | |
1160 | } | |
1da177e4 LT |
1161 | EXPORT_SYMBOL(compute_creds); |
1162 | ||
4fc75ff4 NP |
1163 | /* |
1164 | * Arguments are '\0' separated strings found at the location bprm->p | |
1165 | * points to; chop off the first by relocating brpm->p to right after | |
1166 | * the first '\0' encountered. | |
1167 | */ | |
b6a2fea3 | 1168 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1169 | { |
b6a2fea3 OW |
1170 | int ret = 0; |
1171 | unsigned long offset; | |
1172 | char *kaddr; | |
1173 | struct page *page; | |
4fc75ff4 | 1174 | |
b6a2fea3 OW |
1175 | if (!bprm->argc) |
1176 | return 0; | |
1da177e4 | 1177 | |
b6a2fea3 OW |
1178 | do { |
1179 | offset = bprm->p & ~PAGE_MASK; | |
1180 | page = get_arg_page(bprm, bprm->p, 0); | |
1181 | if (!page) { | |
1182 | ret = -EFAULT; | |
1183 | goto out; | |
1184 | } | |
1185 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1186 | |
b6a2fea3 OW |
1187 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1188 | offset++, bprm->p++) | |
1189 | ; | |
4fc75ff4 | 1190 | |
b6a2fea3 OW |
1191 | kunmap_atomic(kaddr, KM_USER0); |
1192 | put_arg_page(page); | |
4fc75ff4 | 1193 | |
b6a2fea3 OW |
1194 | if (offset == PAGE_SIZE) |
1195 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1196 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1197 | |
b6a2fea3 OW |
1198 | bprm->p++; |
1199 | bprm->argc--; | |
1200 | ret = 0; | |
4fc75ff4 | 1201 | |
b6a2fea3 OW |
1202 | out: |
1203 | return ret; | |
1da177e4 | 1204 | } |
1da177e4 LT |
1205 | EXPORT_SYMBOL(remove_arg_zero); |
1206 | ||
1207 | /* | |
1208 | * cycle the list of binary formats handler, until one recognizes the image | |
1209 | */ | |
1210 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1211 | { | |
1212 | int try,retval; | |
1213 | struct linux_binfmt *fmt; | |
1214 | #ifdef __alpha__ | |
1215 | /* handle /sbin/loader.. */ | |
1216 | { | |
1217 | struct exec * eh = (struct exec *) bprm->buf; | |
1218 | ||
1219 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1220 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1221 | { | |
1222 | struct file * file; | |
1223 | unsigned long loader; | |
1224 | ||
1225 | allow_write_access(bprm->file); | |
1226 | fput(bprm->file); | |
1227 | bprm->file = NULL; | |
1228 | ||
b6a2fea3 | 1229 | loader = bprm->vma->vm_end - sizeof(void *); |
1da177e4 LT |
1230 | |
1231 | file = open_exec("/sbin/loader"); | |
1232 | retval = PTR_ERR(file); | |
1233 | if (IS_ERR(file)) | |
1234 | return retval; | |
1235 | ||
1236 | /* Remember if the application is TASO. */ | |
1237 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1238 | ||
1239 | bprm->file = file; | |
1240 | bprm->loader = loader; | |
1241 | retval = prepare_binprm(bprm); | |
1242 | if (retval<0) | |
1243 | return retval; | |
1244 | /* should call search_binary_handler recursively here, | |
1245 | but it does not matter */ | |
1246 | } | |
1247 | } | |
1248 | #endif | |
1249 | retval = security_bprm_check(bprm); | |
1250 | if (retval) | |
1251 | return retval; | |
1252 | ||
1253 | /* kernel module loader fixup */ | |
1254 | /* so we don't try to load run modprobe in kernel space. */ | |
1255 | set_fs(USER_DS); | |
473ae30b AV |
1256 | |
1257 | retval = audit_bprm(bprm); | |
1258 | if (retval) | |
1259 | return retval; | |
1260 | ||
1da177e4 LT |
1261 | retval = -ENOENT; |
1262 | for (try=0; try<2; try++) { | |
1263 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1264 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1265 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1266 | if (!fn) | |
1267 | continue; | |
1268 | if (!try_module_get(fmt->module)) | |
1269 | continue; | |
1270 | read_unlock(&binfmt_lock); | |
1271 | retval = fn(bprm, regs); | |
1272 | if (retval >= 0) { | |
1273 | put_binfmt(fmt); | |
1274 | allow_write_access(bprm->file); | |
1275 | if (bprm->file) | |
1276 | fput(bprm->file); | |
1277 | bprm->file = NULL; | |
1278 | current->did_exec = 1; | |
9f46080c | 1279 | proc_exec_connector(current); |
1da177e4 LT |
1280 | return retval; |
1281 | } | |
1282 | read_lock(&binfmt_lock); | |
1283 | put_binfmt(fmt); | |
1284 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1285 | break; | |
1286 | if (!bprm->file) { | |
1287 | read_unlock(&binfmt_lock); | |
1288 | return retval; | |
1289 | } | |
1290 | } | |
1291 | read_unlock(&binfmt_lock); | |
1292 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1293 | break; | |
1294 | #ifdef CONFIG_KMOD | |
1295 | }else{ | |
1296 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1297 | if (printable(bprm->buf[0]) && | |
1298 | printable(bprm->buf[1]) && | |
1299 | printable(bprm->buf[2]) && | |
1300 | printable(bprm->buf[3])) | |
1301 | break; /* -ENOEXEC */ | |
1302 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1303 | #endif | |
1304 | } | |
1305 | } | |
1306 | return retval; | |
1307 | } | |
1308 | ||
1309 | EXPORT_SYMBOL(search_binary_handler); | |
1310 | ||
1311 | /* | |
1312 | * sys_execve() executes a new program. | |
1313 | */ | |
1314 | int do_execve(char * filename, | |
1315 | char __user *__user *argv, | |
1316 | char __user *__user *envp, | |
1317 | struct pt_regs * regs) | |
1318 | { | |
1319 | struct linux_binprm *bprm; | |
1320 | struct file *file; | |
bdf4c48a | 1321 | unsigned long env_p; |
1da177e4 | 1322 | int retval; |
1da177e4 LT |
1323 | |
1324 | retval = -ENOMEM; | |
11b0b5ab | 1325 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 LT |
1326 | if (!bprm) |
1327 | goto out_ret; | |
1da177e4 LT |
1328 | |
1329 | file = open_exec(filename); | |
1330 | retval = PTR_ERR(file); | |
1331 | if (IS_ERR(file)) | |
1332 | goto out_kfree; | |
1333 | ||
1334 | sched_exec(); | |
1335 | ||
1da177e4 LT |
1336 | bprm->file = file; |
1337 | bprm->filename = filename; | |
1338 | bprm->interp = filename; | |
1da177e4 | 1339 | |
b6a2fea3 OW |
1340 | retval = bprm_mm_init(bprm); |
1341 | if (retval) | |
1342 | goto out_file; | |
1da177e4 | 1343 | |
b6a2fea3 | 1344 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 LT |
1345 | if ((retval = bprm->argc) < 0) |
1346 | goto out_mm; | |
1347 | ||
b6a2fea3 | 1348 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 LT |
1349 | if ((retval = bprm->envc) < 0) |
1350 | goto out_mm; | |
1351 | ||
1352 | retval = security_bprm_alloc(bprm); | |
1353 | if (retval) | |
1354 | goto out; | |
1355 | ||
1356 | retval = prepare_binprm(bprm); | |
1357 | if (retval < 0) | |
1358 | goto out; | |
1359 | ||
1360 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1361 | if (retval < 0) | |
1362 | goto out; | |
1363 | ||
1364 | bprm->exec = bprm->p; | |
1365 | retval = copy_strings(bprm->envc, envp, bprm); | |
1366 | if (retval < 0) | |
1367 | goto out; | |
1368 | ||
bdf4c48a | 1369 | env_p = bprm->p; |
1da177e4 LT |
1370 | retval = copy_strings(bprm->argc, argv, bprm); |
1371 | if (retval < 0) | |
1372 | goto out; | |
bdf4c48a | 1373 | bprm->argv_len = env_p - bprm->p; |
1da177e4 LT |
1374 | |
1375 | retval = search_binary_handler(bprm,regs); | |
1376 | if (retval >= 0) { | |
1da177e4 | 1377 | /* execve success */ |
b6a2fea3 | 1378 | free_arg_pages(bprm); |
1da177e4 LT |
1379 | security_bprm_free(bprm); |
1380 | acct_update_integrals(current); | |
1da177e4 LT |
1381 | kfree(bprm); |
1382 | return retval; | |
1383 | } | |
1384 | ||
1385 | out: | |
b6a2fea3 | 1386 | free_arg_pages(bprm); |
1da177e4 LT |
1387 | if (bprm->security) |
1388 | security_bprm_free(bprm); | |
1389 | ||
1390 | out_mm: | |
1391 | if (bprm->mm) | |
b6a2fea3 | 1392 | mmput (bprm->mm); |
1da177e4 LT |
1393 | |
1394 | out_file: | |
1395 | if (bprm->file) { | |
1396 | allow_write_access(bprm->file); | |
1397 | fput(bprm->file); | |
1398 | } | |
1da177e4 LT |
1399 | out_kfree: |
1400 | kfree(bprm); | |
1401 | ||
1402 | out_ret: | |
1403 | return retval; | |
1404 | } | |
1405 | ||
1406 | int set_binfmt(struct linux_binfmt *new) | |
1407 | { | |
1408 | struct linux_binfmt *old = current->binfmt; | |
1409 | ||
1410 | if (new) { | |
1411 | if (!try_module_get(new->module)) | |
1412 | return -1; | |
1413 | } | |
1414 | current->binfmt = new; | |
1415 | if (old) | |
1416 | module_put(old->module); | |
1417 | return 0; | |
1418 | } | |
1419 | ||
1420 | EXPORT_SYMBOL(set_binfmt); | |
1421 | ||
1da177e4 LT |
1422 | /* format_corename will inspect the pattern parameter, and output a |
1423 | * name into corename, which must have space for at least | |
1424 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1425 | */ | |
c4bbafda | 1426 | static int format_corename(char *corename, const char *pattern, long signr) |
1da177e4 LT |
1427 | { |
1428 | const char *pat_ptr = pattern; | |
1429 | char *out_ptr = corename; | |
1430 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1431 | int rc; | |
1432 | int pid_in_pattern = 0; | |
c4bbafda AC |
1433 | int ispipe = 0; |
1434 | ||
1435 | if (*pattern == '|') | |
1436 | ispipe = 1; | |
1da177e4 LT |
1437 | |
1438 | /* Repeat as long as we have more pattern to process and more output | |
1439 | space */ | |
1440 | while (*pat_ptr) { | |
1441 | if (*pat_ptr != '%') { | |
1442 | if (out_ptr == out_end) | |
1443 | goto out; | |
1444 | *out_ptr++ = *pat_ptr++; | |
1445 | } else { | |
1446 | switch (*++pat_ptr) { | |
1447 | case 0: | |
1448 | goto out; | |
1449 | /* Double percent, output one percent */ | |
1450 | case '%': | |
1451 | if (out_ptr == out_end) | |
1452 | goto out; | |
1453 | *out_ptr++ = '%'; | |
1454 | break; | |
1455 | /* pid */ | |
1456 | case 'p': | |
1457 | pid_in_pattern = 1; | |
1458 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1459 | "%d", current->tgid); | |
1460 | if (rc > out_end - out_ptr) | |
1461 | goto out; | |
1462 | out_ptr += rc; | |
1463 | break; | |
1464 | /* uid */ | |
1465 | case 'u': | |
1466 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1467 | "%d", current->uid); | |
1468 | if (rc > out_end - out_ptr) | |
1469 | goto out; | |
1470 | out_ptr += rc; | |
1471 | break; | |
1472 | /* gid */ | |
1473 | case 'g': | |
1474 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1475 | "%d", current->gid); | |
1476 | if (rc > out_end - out_ptr) | |
1477 | goto out; | |
1478 | out_ptr += rc; | |
1479 | break; | |
1480 | /* signal that caused the coredump */ | |
1481 | case 's': | |
1482 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1483 | "%ld", signr); | |
1484 | if (rc > out_end - out_ptr) | |
1485 | goto out; | |
1486 | out_ptr += rc; | |
1487 | break; | |
1488 | /* UNIX time of coredump */ | |
1489 | case 't': { | |
1490 | struct timeval tv; | |
1491 | do_gettimeofday(&tv); | |
1492 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1493 | "%lu", tv.tv_sec); | |
1494 | if (rc > out_end - out_ptr) | |
1495 | goto out; | |
1496 | out_ptr += rc; | |
1497 | break; | |
1498 | } | |
1499 | /* hostname */ | |
1500 | case 'h': | |
1501 | down_read(&uts_sem); | |
1502 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1503 | "%s", utsname()->nodename); |
1da177e4 LT |
1504 | up_read(&uts_sem); |
1505 | if (rc > out_end - out_ptr) | |
1506 | goto out; | |
1507 | out_ptr += rc; | |
1508 | break; | |
1509 | /* executable */ | |
1510 | case 'e': | |
1511 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1512 | "%s", current->comm); | |
1513 | if (rc > out_end - out_ptr) | |
1514 | goto out; | |
1515 | out_ptr += rc; | |
1516 | break; | |
1517 | default: | |
1518 | break; | |
1519 | } | |
1520 | ++pat_ptr; | |
1521 | } | |
1522 | } | |
1523 | /* Backward compatibility with core_uses_pid: | |
1524 | * | |
1525 | * If core_pattern does not include a %p (as is the default) | |
1526 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda AC |
1527 | * the filename. Do not do this for piped commands. */ |
1528 | if (!ispipe && !pid_in_pattern | |
1da177e4 LT |
1529 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { |
1530 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1531 | ".%d", current->tgid); | |
1532 | if (rc > out_end - out_ptr) | |
1533 | goto out; | |
1534 | out_ptr += rc; | |
1535 | } | |
c4bbafda | 1536 | out: |
1da177e4 | 1537 | *out_ptr = 0; |
c4bbafda | 1538 | return ispipe; |
1da177e4 LT |
1539 | } |
1540 | ||
d5f70c00 | 1541 | static void zap_process(struct task_struct *start) |
aceecc04 ON |
1542 | { |
1543 | struct task_struct *t; | |
281de339 | 1544 | |
d5f70c00 ON |
1545 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1546 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1547 | |
1548 | t = start; | |
1549 | do { | |
1550 | if (t != current && t->mm) { | |
1551 | t->mm->core_waiters++; | |
281de339 ON |
1552 | sigaddset(&t->pending.signal, SIGKILL); |
1553 | signal_wake_up(t, 1); | |
aceecc04 ON |
1554 | } |
1555 | } while ((t = next_thread(t)) != start); | |
1556 | } | |
1557 | ||
dcf560c5 ON |
1558 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
1559 | int exit_code) | |
1da177e4 LT |
1560 | { |
1561 | struct task_struct *g, *p; | |
5debfa6d | 1562 | unsigned long flags; |
dcf560c5 ON |
1563 | int err = -EAGAIN; |
1564 | ||
1565 | spin_lock_irq(&tsk->sighand->siglock); | |
1566 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) { | |
dcf560c5 | 1567 | tsk->signal->group_exit_code = exit_code; |
5debfa6d | 1568 | zap_process(tsk); |
dcf560c5 | 1569 | err = 0; |
1da177e4 | 1570 | } |
dcf560c5 ON |
1571 | spin_unlock_irq(&tsk->sighand->siglock); |
1572 | if (err) | |
1573 | return err; | |
1da177e4 | 1574 | |
5debfa6d ON |
1575 | if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) |
1576 | goto done; | |
1577 | ||
7b1c6154 | 1578 | rcu_read_lock(); |
aceecc04 | 1579 | for_each_process(g) { |
5debfa6d ON |
1580 | if (g == tsk->group_leader) |
1581 | continue; | |
1582 | ||
aceecc04 ON |
1583 | p = g; |
1584 | do { | |
1585 | if (p->mm) { | |
5debfa6d ON |
1586 | if (p->mm == mm) { |
1587 | /* | |
1588 | * p->sighand can't disappear, but | |
1589 | * may be changed by de_thread() | |
1590 | */ | |
1591 | lock_task_sighand(p, &flags); | |
d5f70c00 | 1592 | zap_process(p); |
5debfa6d ON |
1593 | unlock_task_sighand(p, &flags); |
1594 | } | |
aceecc04 ON |
1595 | break; |
1596 | } | |
1597 | } while ((p = next_thread(p)) != g); | |
1598 | } | |
7b1c6154 | 1599 | rcu_read_unlock(); |
5debfa6d | 1600 | done: |
dcf560c5 | 1601 | return mm->core_waiters; |
1da177e4 LT |
1602 | } |
1603 | ||
dcf560c5 | 1604 | static int coredump_wait(int exit_code) |
1da177e4 | 1605 | { |
dcf560c5 ON |
1606 | struct task_struct *tsk = current; |
1607 | struct mm_struct *mm = tsk->mm; | |
1608 | struct completion startup_done; | |
1609 | struct completion *vfork_done; | |
2384f55f | 1610 | int core_waiters; |
1da177e4 | 1611 | |
dcf560c5 ON |
1612 | init_completion(&mm->core_done); |
1613 | init_completion(&startup_done); | |
1da177e4 LT |
1614 | mm->core_startup_done = &startup_done; |
1615 | ||
dcf560c5 | 1616 | core_waiters = zap_threads(tsk, mm, exit_code); |
2384f55f ON |
1617 | up_write(&mm->mmap_sem); |
1618 | ||
dcf560c5 ON |
1619 | if (unlikely(core_waiters < 0)) |
1620 | goto fail; | |
1621 | ||
1622 | /* | |
1623 | * Make sure nobody is waiting for us to release the VM, | |
1624 | * otherwise we can deadlock when we wait on each other | |
1625 | */ | |
1626 | vfork_done = tsk->vfork_done; | |
1627 | if (vfork_done) { | |
1628 | tsk->vfork_done = NULL; | |
1629 | complete(vfork_done); | |
1630 | } | |
1631 | ||
2384f55f | 1632 | if (core_waiters) |
1da177e4 | 1633 | wait_for_completion(&startup_done); |
dcf560c5 | 1634 | fail: |
1da177e4 | 1635 | BUG_ON(mm->core_waiters); |
dcf560c5 | 1636 | return core_waiters; |
1da177e4 LT |
1637 | } |
1638 | ||
6c5d5238 KH |
1639 | /* |
1640 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1641 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1642 | * these bits are not changed atomically. So get_dumpable can observe the | |
1643 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1644 | * return either old dumpable or new one by paying attention to the order of | |
1645 | * modifying the bits. | |
1646 | * | |
1647 | * dumpable | mm->flags (binary) | |
1648 | * old new | initial interim final | |
1649 | * ---------+----------------------- | |
1650 | * 0 1 | 00 01 01 | |
1651 | * 0 2 | 00 10(*) 11 | |
1652 | * 1 0 | 01 00 00 | |
1653 | * 1 2 | 01 11 11 | |
1654 | * 2 0 | 11 10(*) 00 | |
1655 | * 2 1 | 11 11 01 | |
1656 | * | |
1657 | * (*) get_dumpable regards interim value of 10 as 11. | |
1658 | */ | |
1659 | void set_dumpable(struct mm_struct *mm, int value) | |
1660 | { | |
1661 | switch (value) { | |
1662 | case 0: | |
1663 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1664 | smp_wmb(); | |
1665 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1666 | break; | |
1667 | case 1: | |
1668 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1669 | smp_wmb(); | |
1670 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1671 | break; | |
1672 | case 2: | |
1673 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1674 | smp_wmb(); | |
1675 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1676 | break; | |
1677 | } | |
1678 | } | |
1679 | EXPORT_SYMBOL_GPL(set_dumpable); | |
1680 | ||
1681 | int get_dumpable(struct mm_struct *mm) | |
1682 | { | |
1683 | int ret; | |
1684 | ||
1685 | ret = mm->flags & 0x3; | |
1686 | return (ret >= 2) ? 2 : ret; | |
1687 | } | |
1688 | ||
1da177e4 LT |
1689 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) |
1690 | { | |
1691 | char corename[CORENAME_MAX_SIZE + 1]; | |
1692 | struct mm_struct *mm = current->mm; | |
1693 | struct linux_binfmt * binfmt; | |
1694 | struct inode * inode; | |
1695 | struct file * file; | |
1696 | int retval = 0; | |
d6e71144 AC |
1697 | int fsuid = current->fsuid; |
1698 | int flag = 0; | |
d025c9db | 1699 | int ispipe = 0; |
7dc0b22e | 1700 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
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 | ||
1da177e4 LT |
1734 | /* |
1735 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1736 | * uses lock_kernel() | |
1737 | */ | |
1738 | lock_kernel(); | |
c4bbafda | 1739 | ispipe = format_corename(corename, core_pattern, signr); |
1da177e4 | 1740 | unlock_kernel(); |
7dc0b22e NH |
1741 | /* |
1742 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1743 | * to a pipe. Since we're not writing directly to the filesystem | |
1744 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1745 | * created unless the pipe reader choses to write out the core file | |
1746 | * at which point file size limits and permissions will be imposed | |
1747 | * as it does with any other process | |
1748 | */ | |
1749 | if ((!ispipe) && | |
1750 | (core_limit < binfmt->min_coredump)) | |
1751 | goto fail_unlock; | |
1752 | ||
c4bbafda | 1753 | if (ispipe) { |
7dc0b22e | 1754 | core_limit = RLIM_INFINITY; |
d025c9db AK |
1755 | /* SIGPIPE can happen, but it's just never processed */ |
1756 | if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) { | |
1757 | printk(KERN_INFO "Core dump to %s pipe failed\n", | |
1758 | corename); | |
1759 | goto fail_unlock; | |
1760 | } | |
d025c9db AK |
1761 | } else |
1762 | file = filp_open(corename, | |
6d4df677 AD |
1763 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1764 | 0600); | |
1da177e4 LT |
1765 | if (IS_ERR(file)) |
1766 | goto fail_unlock; | |
0f7fc9e4 | 1767 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1768 | if (inode->i_nlink > 1) |
1769 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1770 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1771 | goto close_fail; |
1772 | ||
d025c9db AK |
1773 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1774 | but keep the previous behaviour for now. */ | |
1775 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 LT |
1776 | goto close_fail; |
1777 | if (!file->f_op) | |
1778 | goto close_fail; | |
1779 | if (!file->f_op->write) | |
1780 | goto close_fail; | |
0f7fc9e4 | 1781 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1782 | goto close_fail; |
1783 | ||
7dc0b22e | 1784 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1785 | |
1786 | if (retval) | |
1787 | current->signal->group_exit_code |= 0x80; | |
1788 | close_fail: | |
1789 | filp_close(file, NULL); | |
1790 | fail_unlock: | |
d6e71144 | 1791 | current->fsuid = fsuid; |
1da177e4 LT |
1792 | complete_all(&mm->core_done); |
1793 | fail: | |
1794 | return retval; | |
1795 | } |