Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/exec.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * #!-checking implemented by tytso. | |
9 | */ | |
10 | /* | |
11 | * Demand-loading implemented 01.12.91 - no need to read anything but | |
12 | * the header into memory. The inode of the executable is put into | |
13 | * "current->executable", and page faults do the actual loading. Clean. | |
14 | * | |
15 | * Once more I can proudly say that linux stood up to being changed: it | |
16 | * was less than 2 hours work to get demand-loading completely implemented. | |
17 | * | |
18 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, | |
19 | * current->executable is only used by the procfs. This allows a dispatch | |
20 | * table to check for several different types of binary formats. We keep | |
21 | * trying until we recognize the file or we run out of supported binary | |
22 | * formats. | |
23 | */ | |
24 | ||
1da177e4 LT |
25 | #include <linux/slab.h> |
26 | #include <linux/file.h> | |
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 | ||
69 | static struct linux_binfmt *formats; | |
70 | static DEFINE_RWLOCK(binfmt_lock); | |
71 | ||
72 | int register_binfmt(struct linux_binfmt * fmt) | |
73 | { | |
74 | struct linux_binfmt ** tmp = &formats; | |
75 | ||
76 | if (!fmt) | |
77 | return -EINVAL; | |
78 | if (fmt->next) | |
79 | return -EBUSY; | |
80 | write_lock(&binfmt_lock); | |
81 | while (*tmp) { | |
82 | if (fmt == *tmp) { | |
83 | write_unlock(&binfmt_lock); | |
84 | return -EBUSY; | |
85 | } | |
86 | tmp = &(*tmp)->next; | |
87 | } | |
88 | fmt->next = formats; | |
89 | formats = fmt; | |
90 | write_unlock(&binfmt_lock); | |
91 | return 0; | |
92 | } | |
93 | ||
94 | EXPORT_SYMBOL(register_binfmt); | |
95 | ||
96 | int unregister_binfmt(struct linux_binfmt * fmt) | |
97 | { | |
98 | struct linux_binfmt ** tmp = &formats; | |
99 | ||
100 | write_lock(&binfmt_lock); | |
101 | while (*tmp) { | |
102 | if (fmt == *tmp) { | |
103 | *tmp = fmt->next; | |
98701d1b | 104 | fmt->next = NULL; |
1da177e4 LT |
105 | write_unlock(&binfmt_lock); |
106 | return 0; | |
107 | } | |
108 | tmp = &(*tmp)->next; | |
109 | } | |
110 | write_unlock(&binfmt_lock); | |
111 | return -EINVAL; | |
112 | } | |
113 | ||
114 | EXPORT_SYMBOL(unregister_binfmt); | |
115 | ||
116 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
117 | { | |
118 | module_put(fmt->module); | |
119 | } | |
120 | ||
121 | /* | |
122 | * Note that a shared library must be both readable and executable due to | |
123 | * security reasons. | |
124 | * | |
125 | * Also note that we take the address to load from from the file itself. | |
126 | */ | |
127 | asmlinkage long sys_uselib(const char __user * library) | |
128 | { | |
129 | struct file * file; | |
130 | struct nameidata nd; | |
131 | int error; | |
132 | ||
b500531e | 133 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
134 | if (error) |
135 | goto out; | |
136 | ||
492c8b33 CH |
137 | error = -EACCES; |
138 | if (nd.mnt->mnt_flags & MNT_NOEXEC) | |
139 | goto exit; | |
1da177e4 LT |
140 | error = -EINVAL; |
141 | if (!S_ISREG(nd.dentry->d_inode->i_mode)) | |
142 | goto exit; | |
143 | ||
e4543edd | 144 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC); |
1da177e4 LT |
145 | if (error) |
146 | goto exit; | |
147 | ||
834f2a4a | 148 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
149 | error = PTR_ERR(file); |
150 | if (IS_ERR(file)) | |
151 | goto out; | |
152 | ||
153 | error = -ENOEXEC; | |
154 | if(file->f_op) { | |
155 | struct linux_binfmt * fmt; | |
156 | ||
157 | read_lock(&binfmt_lock); | |
158 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
159 | if (!fmt->load_shlib) | |
160 | continue; | |
161 | if (!try_module_get(fmt->module)) | |
162 | continue; | |
163 | read_unlock(&binfmt_lock); | |
164 | error = fmt->load_shlib(file); | |
165 | read_lock(&binfmt_lock); | |
166 | put_binfmt(fmt); | |
167 | if (error != -ENOEXEC) | |
168 | break; | |
169 | } | |
170 | read_unlock(&binfmt_lock); | |
171 | } | |
172 | fput(file); | |
173 | out: | |
174 | return error; | |
175 | exit: | |
834f2a4a | 176 | release_open_intent(&nd); |
1da177e4 LT |
177 | path_release(&nd); |
178 | goto out; | |
179 | } | |
180 | ||
b6a2fea3 OW |
181 | #ifdef CONFIG_MMU |
182 | ||
183 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
184 | int write) | |
185 | { | |
186 | struct page *page; | |
187 | int ret; | |
188 | ||
189 | #ifdef CONFIG_STACK_GROWSUP | |
190 | if (write) { | |
191 | ret = expand_stack_downwards(bprm->vma, pos); | |
192 | if (ret < 0) | |
193 | return NULL; | |
194 | } | |
195 | #endif | |
196 | ret = get_user_pages(current, bprm->mm, pos, | |
197 | 1, write, 1, &page, NULL); | |
198 | if (ret <= 0) | |
199 | return NULL; | |
200 | ||
201 | if (write) { | |
202 | struct rlimit *rlim = current->signal->rlim; | |
203 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; | |
204 | ||
205 | /* | |
206 | * Limit to 1/4-th the stack size for the argv+env strings. | |
207 | * This ensures that: | |
208 | * - the remaining binfmt code will not run out of stack space, | |
209 | * - the program will have a reasonable amount of stack left | |
210 | * to work from. | |
211 | */ | |
212 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { | |
213 | put_page(page); | |
214 | return NULL; | |
215 | } | |
216 | } | |
217 | ||
218 | return page; | |
219 | } | |
220 | ||
221 | static void put_arg_page(struct page *page) | |
222 | { | |
223 | put_page(page); | |
224 | } | |
225 | ||
226 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
227 | { | |
228 | } | |
229 | ||
230 | static void free_arg_pages(struct linux_binprm *bprm) | |
231 | { | |
232 | } | |
233 | ||
234 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
235 | struct page *page) | |
236 | { | |
237 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
238 | } | |
239 | ||
240 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
241 | { | |
242 | int err = -ENOMEM; | |
243 | struct vm_area_struct *vma = NULL; | |
244 | struct mm_struct *mm = bprm->mm; | |
245 | ||
246 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
247 | if (!vma) | |
248 | goto err; | |
249 | ||
250 | down_write(&mm->mmap_sem); | |
251 | vma->vm_mm = mm; | |
252 | ||
253 | /* | |
254 | * Place the stack at the largest stack address the architecture | |
255 | * supports. Later, we'll move this to an appropriate place. We don't | |
256 | * use STACK_TOP because that can depend on attributes which aren't | |
257 | * configured yet. | |
258 | */ | |
259 | vma->vm_end = STACK_TOP_MAX; | |
260 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
261 | ||
262 | vma->vm_flags = VM_STACK_FLAGS; | |
263 | vma->vm_page_prot = protection_map[vma->vm_flags & 0x7]; | |
264 | err = insert_vm_struct(mm, vma); | |
265 | if (err) { | |
266 | up_write(&mm->mmap_sem); | |
267 | goto err; | |
268 | } | |
269 | ||
270 | mm->stack_vm = mm->total_vm = 1; | |
271 | up_write(&mm->mmap_sem); | |
272 | ||
273 | bprm->p = vma->vm_end - sizeof(void *); | |
274 | ||
275 | return 0; | |
276 | ||
277 | err: | |
278 | if (vma) { | |
279 | bprm->vma = NULL; | |
280 | kmem_cache_free(vm_area_cachep, vma); | |
281 | } | |
282 | ||
283 | return err; | |
284 | } | |
285 | ||
286 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
287 | { | |
288 | return len <= MAX_ARG_STRLEN; | |
289 | } | |
290 | ||
291 | #else | |
292 | ||
293 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
294 | int write) | |
295 | { | |
296 | struct page *page; | |
297 | ||
298 | page = bprm->page[pos / PAGE_SIZE]; | |
299 | if (!page && write) { | |
300 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
301 | if (!page) | |
302 | return NULL; | |
303 | bprm->page[pos / PAGE_SIZE] = page; | |
304 | } | |
305 | ||
306 | return page; | |
307 | } | |
308 | ||
309 | static void put_arg_page(struct page *page) | |
310 | { | |
311 | } | |
312 | ||
313 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
314 | { | |
315 | if (bprm->page[i]) { | |
316 | __free_page(bprm->page[i]); | |
317 | bprm->page[i] = NULL; | |
318 | } | |
319 | } | |
320 | ||
321 | static void free_arg_pages(struct linux_binprm *bprm) | |
322 | { | |
323 | int i; | |
324 | ||
325 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
326 | free_arg_page(bprm, i); | |
327 | } | |
328 | ||
329 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
330 | struct page *page) | |
331 | { | |
332 | } | |
333 | ||
334 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
335 | { | |
336 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
337 | return 0; | |
338 | } | |
339 | ||
340 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
341 | { | |
342 | return len <= bprm->p; | |
343 | } | |
344 | ||
345 | #endif /* CONFIG_MMU */ | |
346 | ||
347 | /* | |
348 | * Create a new mm_struct and populate it with a temporary stack | |
349 | * vm_area_struct. We don't have enough context at this point to set the stack | |
350 | * flags, permissions, and offset, so we use temporary values. We'll update | |
351 | * them later in setup_arg_pages(). | |
352 | */ | |
353 | int bprm_mm_init(struct linux_binprm *bprm) | |
354 | { | |
355 | int err; | |
356 | struct mm_struct *mm = NULL; | |
357 | ||
358 | bprm->mm = mm = mm_alloc(); | |
359 | err = -ENOMEM; | |
360 | if (!mm) | |
361 | goto err; | |
362 | ||
363 | err = init_new_context(current, mm); | |
364 | if (err) | |
365 | goto err; | |
366 | ||
367 | err = __bprm_mm_init(bprm); | |
368 | if (err) | |
369 | goto err; | |
370 | ||
371 | return 0; | |
372 | ||
373 | err: | |
374 | if (mm) { | |
375 | bprm->mm = NULL; | |
376 | mmdrop(mm); | |
377 | } | |
378 | ||
379 | return err; | |
380 | } | |
381 | ||
1da177e4 LT |
382 | /* |
383 | * count() counts the number of strings in array ARGV. | |
384 | */ | |
385 | static int count(char __user * __user * argv, int max) | |
386 | { | |
387 | int i = 0; | |
388 | ||
389 | if (argv != NULL) { | |
390 | for (;;) { | |
391 | char __user * p; | |
392 | ||
393 | if (get_user(p, argv)) | |
394 | return -EFAULT; | |
395 | if (!p) | |
396 | break; | |
397 | argv++; | |
398 | if(++i > max) | |
399 | return -E2BIG; | |
400 | cond_resched(); | |
401 | } | |
402 | } | |
403 | return i; | |
404 | } | |
405 | ||
406 | /* | |
b6a2fea3 OW |
407 | * 'copy_strings()' copies argument/environment strings from the old |
408 | * processes's memory to the new process's stack. The call to get_user_pages() | |
409 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 410 | */ |
75c96f85 AB |
411 | static int copy_strings(int argc, char __user * __user * argv, |
412 | struct linux_binprm *bprm) | |
1da177e4 LT |
413 | { |
414 | struct page *kmapped_page = NULL; | |
415 | char *kaddr = NULL; | |
b6a2fea3 | 416 | unsigned long kpos = 0; |
1da177e4 LT |
417 | int ret; |
418 | ||
419 | while (argc-- > 0) { | |
420 | char __user *str; | |
421 | int len; | |
422 | unsigned long pos; | |
423 | ||
424 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 425 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
426 | ret = -EFAULT; |
427 | goto out; | |
428 | } | |
429 | ||
b6a2fea3 | 430 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
431 | ret = -E2BIG; |
432 | goto out; | |
433 | } | |
434 | ||
b6a2fea3 | 435 | /* We're going to work our way backwords. */ |
1da177e4 | 436 | pos = bprm->p; |
b6a2fea3 OW |
437 | str += len; |
438 | bprm->p -= len; | |
1da177e4 LT |
439 | |
440 | while (len > 0) { | |
1da177e4 | 441 | int offset, bytes_to_copy; |
1da177e4 LT |
442 | |
443 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
444 | if (offset == 0) |
445 | offset = PAGE_SIZE; | |
446 | ||
447 | bytes_to_copy = offset; | |
448 | if (bytes_to_copy > len) | |
449 | bytes_to_copy = len; | |
450 | ||
451 | offset -= bytes_to_copy; | |
452 | pos -= bytes_to_copy; | |
453 | str -= bytes_to_copy; | |
454 | len -= bytes_to_copy; | |
455 | ||
456 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
457 | struct page *page; | |
458 | ||
459 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 460 | if (!page) { |
b6a2fea3 | 461 | ret = -E2BIG; |
1da177e4 LT |
462 | goto out; |
463 | } | |
1da177e4 | 464 | |
b6a2fea3 OW |
465 | if (kmapped_page) { |
466 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 467 | kunmap(kmapped_page); |
b6a2fea3 OW |
468 | put_arg_page(kmapped_page); |
469 | } | |
1da177e4 LT |
470 | kmapped_page = page; |
471 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
472 | kpos = pos & PAGE_MASK; |
473 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 474 | } |
b6a2fea3 | 475 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
476 | ret = -EFAULT; |
477 | goto out; | |
478 | } | |
1da177e4 LT |
479 | } |
480 | } | |
481 | ret = 0; | |
482 | out: | |
b6a2fea3 OW |
483 | if (kmapped_page) { |
484 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 485 | kunmap(kmapped_page); |
b6a2fea3 OW |
486 | put_arg_page(kmapped_page); |
487 | } | |
1da177e4 LT |
488 | return ret; |
489 | } | |
490 | ||
491 | /* | |
492 | * Like copy_strings, but get argv and its values from kernel memory. | |
493 | */ | |
494 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
495 | { | |
496 | int r; | |
497 | mm_segment_t oldfs = get_fs(); | |
498 | set_fs(KERNEL_DS); | |
499 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
500 | set_fs(oldfs); | |
501 | return r; | |
502 | } | |
1da177e4 LT |
503 | EXPORT_SYMBOL(copy_strings_kernel); |
504 | ||
505 | #ifdef CONFIG_MMU | |
b6a2fea3 | 506 | |
1da177e4 | 507 | /* |
b6a2fea3 OW |
508 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
509 | * the binfmt code determines where the new stack should reside, we shift it to | |
510 | * its final location. The process proceeds as follows: | |
1da177e4 | 511 | * |
b6a2fea3 OW |
512 | * 1) Use shift to calculate the new vma endpoints. |
513 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
514 | * arguments passed to subsequent functions are consistent. | |
515 | * 3) Move vma's page tables to the new range. | |
516 | * 4) Free up any cleared pgd range. | |
517 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 518 | */ |
b6a2fea3 | 519 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
520 | { |
521 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
522 | unsigned long old_start = vma->vm_start; |
523 | unsigned long old_end = vma->vm_end; | |
524 | unsigned long length = old_end - old_start; | |
525 | unsigned long new_start = old_start - shift; | |
526 | unsigned long new_end = old_end - shift; | |
527 | struct mmu_gather *tlb; | |
1da177e4 | 528 | |
b6a2fea3 | 529 | BUG_ON(new_start > new_end); |
1da177e4 | 530 | |
b6a2fea3 OW |
531 | /* |
532 | * ensure there are no vmas between where we want to go | |
533 | * and where we are | |
534 | */ | |
535 | if (vma != find_vma(mm, new_start)) | |
536 | return -EFAULT; | |
537 | ||
538 | /* | |
539 | * cover the whole range: [new_start, old_end) | |
540 | */ | |
541 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
542 | ||
543 | /* | |
544 | * move the page tables downwards, on failure we rely on | |
545 | * process cleanup to remove whatever mess we made. | |
546 | */ | |
547 | if (length != move_page_tables(vma, old_start, | |
548 | vma, new_start, length)) | |
549 | return -ENOMEM; | |
550 | ||
551 | lru_add_drain(); | |
552 | tlb = tlb_gather_mmu(mm, 0); | |
553 | if (new_end > old_start) { | |
554 | /* | |
555 | * when the old and new regions overlap clear from new_end. | |
556 | */ | |
557 | free_pgd_range(&tlb, new_end, old_end, new_end, | |
558 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
559 | } else { | |
560 | /* | |
561 | * otherwise, clean from old_start; this is done to not touch | |
562 | * the address space in [new_end, old_start) some architectures | |
563 | * have constraints on va-space that make this illegal (IA64) - | |
564 | * for the others its just a little faster. | |
565 | */ | |
566 | free_pgd_range(&tlb, old_start, old_end, new_end, | |
567 | vma->vm_next ? vma->vm_next->vm_start : 0); | |
1da177e4 | 568 | } |
b6a2fea3 OW |
569 | tlb_finish_mmu(tlb, new_end, old_end); |
570 | ||
571 | /* | |
572 | * shrink the vma to just the new range. | |
573 | */ | |
574 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
575 | ||
576 | return 0; | |
1da177e4 LT |
577 | } |
578 | ||
579 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
580 | ||
b6a2fea3 OW |
581 | /* |
582 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
583 | * the stack is optionally relocated, and some extra space is added. | |
584 | */ | |
1da177e4 LT |
585 | int setup_arg_pages(struct linux_binprm *bprm, |
586 | unsigned long stack_top, | |
587 | int executable_stack) | |
588 | { | |
b6a2fea3 OW |
589 | unsigned long ret; |
590 | unsigned long stack_shift; | |
1da177e4 | 591 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
592 | struct vm_area_struct *vma = bprm->vma; |
593 | struct vm_area_struct *prev = NULL; | |
594 | unsigned long vm_flags; | |
595 | unsigned long stack_base; | |
1da177e4 LT |
596 | |
597 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
598 | /* Limit stack size to 1GB */ |
599 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
600 | if (stack_base > (1 << 30)) | |
601 | stack_base = 1 << 30; | |
1da177e4 | 602 | |
b6a2fea3 OW |
603 | /* Make sure we didn't let the argument array grow too large. */ |
604 | if (vma->vm_end - vma->vm_start > stack_base) | |
605 | return -ENOMEM; | |
1da177e4 | 606 | |
b6a2fea3 | 607 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 608 | |
b6a2fea3 OW |
609 | stack_shift = vma->vm_start - stack_base; |
610 | mm->arg_start = bprm->p - stack_shift; | |
611 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 612 | #else |
b6a2fea3 OW |
613 | stack_top = arch_align_stack(stack_top); |
614 | stack_top = PAGE_ALIGN(stack_top); | |
615 | stack_shift = vma->vm_end - stack_top; | |
616 | ||
617 | bprm->p -= stack_shift; | |
1da177e4 | 618 | mm->arg_start = bprm->p; |
1da177e4 LT |
619 | #endif |
620 | ||
1da177e4 | 621 | if (bprm->loader) |
b6a2fea3 OW |
622 | bprm->loader -= stack_shift; |
623 | bprm->exec -= stack_shift; | |
1da177e4 | 624 | |
1da177e4 | 625 | down_write(&mm->mmap_sem); |
b6a2fea3 OW |
626 | vm_flags = vma->vm_flags; |
627 | ||
628 | /* | |
629 | * Adjust stack execute permissions; explicitly enable for | |
630 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
631 | * (arch default) otherwise. | |
632 | */ | |
633 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
634 | vm_flags |= VM_EXEC; | |
635 | else if (executable_stack == EXSTACK_DISABLE_X) | |
636 | vm_flags &= ~VM_EXEC; | |
637 | vm_flags |= mm->def_flags; | |
638 | ||
639 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
640 | vm_flags); | |
641 | if (ret) | |
642 | goto out_unlock; | |
643 | BUG_ON(prev != vma); | |
644 | ||
645 | /* Move stack pages down in memory. */ | |
646 | if (stack_shift) { | |
647 | ret = shift_arg_pages(vma, stack_shift); | |
648 | if (ret) { | |
1da177e4 | 649 | up_write(&mm->mmap_sem); |
1da177e4 LT |
650 | return ret; |
651 | } | |
1da177e4 LT |
652 | } |
653 | ||
b6a2fea3 OW |
654 | #ifdef CONFIG_STACK_GROWSUP |
655 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
656 | #else | |
657 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
658 | #endif | |
659 | ret = expand_stack(vma, stack_base); | |
660 | if (ret) | |
661 | ret = -EFAULT; | |
662 | ||
663 | out_unlock: | |
1da177e4 | 664 | up_write(&mm->mmap_sem); |
1da177e4 LT |
665 | return 0; |
666 | } | |
1da177e4 LT |
667 | EXPORT_SYMBOL(setup_arg_pages); |
668 | ||
1da177e4 LT |
669 | #endif /* CONFIG_MMU */ |
670 | ||
671 | struct file *open_exec(const char *name) | |
672 | { | |
673 | struct nameidata nd; | |
674 | int err; | |
675 | struct file *file; | |
676 | ||
b500531e | 677 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
678 | file = ERR_PTR(err); |
679 | ||
680 | if (!err) { | |
681 | struct inode *inode = nd.dentry->d_inode; | |
682 | file = ERR_PTR(-EACCES); | |
683 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && | |
684 | S_ISREG(inode->i_mode)) { | |
e4543edd | 685 | int err = vfs_permission(&nd, MAY_EXEC); |
1da177e4 LT |
686 | file = ERR_PTR(err); |
687 | if (!err) { | |
834f2a4a | 688 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
689 | if (!IS_ERR(file)) { |
690 | err = deny_write_access(file); | |
691 | if (err) { | |
692 | fput(file); | |
693 | file = ERR_PTR(err); | |
694 | } | |
695 | } | |
696 | out: | |
697 | return file; | |
698 | } | |
699 | } | |
834f2a4a | 700 | release_open_intent(&nd); |
1da177e4 LT |
701 | path_release(&nd); |
702 | } | |
703 | goto out; | |
704 | } | |
705 | ||
706 | EXPORT_SYMBOL(open_exec); | |
707 | ||
708 | int kernel_read(struct file *file, unsigned long offset, | |
709 | char *addr, unsigned long count) | |
710 | { | |
711 | mm_segment_t old_fs; | |
712 | loff_t pos = offset; | |
713 | int result; | |
714 | ||
715 | old_fs = get_fs(); | |
716 | set_fs(get_ds()); | |
717 | /* The cast to a user pointer is valid due to the set_fs() */ | |
718 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
719 | set_fs(old_fs); | |
720 | return result; | |
721 | } | |
722 | ||
723 | EXPORT_SYMBOL(kernel_read); | |
724 | ||
725 | static int exec_mmap(struct mm_struct *mm) | |
726 | { | |
727 | struct task_struct *tsk; | |
728 | struct mm_struct * old_mm, *active_mm; | |
729 | ||
730 | /* Notify parent that we're no longer interested in the old VM */ | |
731 | tsk = current; | |
732 | old_mm = current->mm; | |
733 | mm_release(tsk, old_mm); | |
734 | ||
735 | if (old_mm) { | |
736 | /* | |
737 | * Make sure that if there is a core dump in progress | |
738 | * for the old mm, we get out and die instead of going | |
739 | * through with the exec. We must hold mmap_sem around | |
740 | * checking core_waiters and changing tsk->mm. The | |
741 | * core-inducing thread will increment core_waiters for | |
742 | * each thread whose ->mm == old_mm. | |
743 | */ | |
744 | down_read(&old_mm->mmap_sem); | |
745 | if (unlikely(old_mm->core_waiters)) { | |
746 | up_read(&old_mm->mmap_sem); | |
747 | return -EINTR; | |
748 | } | |
749 | } | |
750 | task_lock(tsk); | |
751 | active_mm = tsk->active_mm; | |
752 | tsk->mm = mm; | |
753 | tsk->active_mm = mm; | |
754 | activate_mm(active_mm, mm); | |
755 | task_unlock(tsk); | |
756 | arch_pick_mmap_layout(mm); | |
757 | if (old_mm) { | |
758 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 759 | BUG_ON(active_mm != old_mm); |
1da177e4 LT |
760 | mmput(old_mm); |
761 | return 0; | |
762 | } | |
763 | mmdrop(active_mm); | |
764 | return 0; | |
765 | } | |
766 | ||
767 | /* | |
768 | * This function makes sure the current process has its own signal table, | |
769 | * so that flush_signal_handlers can later reset the handlers without | |
770 | * disturbing other processes. (Other processes might share the signal | |
771 | * table via the CLONE_SIGHAND option to clone().) | |
772 | */ | |
858119e1 | 773 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
774 | { |
775 | struct signal_struct *sig = tsk->signal; | |
776 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand; | |
777 | spinlock_t *lock = &oldsighand->siglock; | |
329f7dba | 778 | struct task_struct *leader = NULL; |
1da177e4 LT |
779 | int count; |
780 | ||
781 | /* | |
782 | * If we don't share sighandlers, then we aren't sharing anything | |
783 | * and we can just re-use it all. | |
784 | */ | |
785 | if (atomic_read(&oldsighand->count) <= 1) { | |
1da177e4 LT |
786 | exit_itimers(sig); |
787 | return 0; | |
788 | } | |
789 | ||
790 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
791 | if (!newsighand) | |
792 | return -ENOMEM; | |
793 | ||
aafe6c2a | 794 | if (thread_group_empty(tsk)) |
1da177e4 LT |
795 | goto no_thread_group; |
796 | ||
797 | /* | |
798 | * Kill all other threads in the thread group. | |
799 | * We must hold tasklist_lock to call zap_other_threads. | |
800 | */ | |
801 | read_lock(&tasklist_lock); | |
802 | spin_lock_irq(lock); | |
803 | if (sig->flags & SIGNAL_GROUP_EXIT) { | |
804 | /* | |
805 | * Another group action in progress, just | |
806 | * return so that the signal is processed. | |
807 | */ | |
808 | spin_unlock_irq(lock); | |
809 | read_unlock(&tasklist_lock); | |
810 | kmem_cache_free(sighand_cachep, newsighand); | |
811 | return -EAGAIN; | |
812 | } | |
1434261c ON |
813 | |
814 | /* | |
815 | * child_reaper ignores SIGKILL, change it now. | |
816 | * Reparenting needs write_lock on tasklist_lock, | |
817 | * so it is safe to do it under read_lock. | |
818 | */ | |
84d73786 SB |
819 | if (unlikely(tsk->group_leader == child_reaper(tsk))) |
820 | tsk->nsproxy->pid_ns->child_reaper = tsk; | |
1434261c | 821 | |
aafe6c2a | 822 | zap_other_threads(tsk); |
1da177e4 LT |
823 | read_unlock(&tasklist_lock); |
824 | ||
825 | /* | |
826 | * Account for the thread group leader hanging around: | |
827 | */ | |
9e4e23bc | 828 | count = 1; |
aafe6c2a | 829 | if (!thread_group_leader(tsk)) { |
9e4e23bc | 830 | count = 2; |
53231250 RM |
831 | /* |
832 | * The SIGALRM timer survives the exec, but needs to point | |
833 | * at us as the new group leader now. We have a race with | |
834 | * a timer firing now getting the old leader, so we need to | |
835 | * synchronize with any firing (by calling del_timer_sync) | |
836 | * before we can safely let the old group leader die. | |
837 | */ | |
aafe6c2a | 838 | sig->tsk = tsk; |
932aeafb | 839 | spin_unlock_irq(lock); |
2ff678b8 TG |
840 | if (hrtimer_cancel(&sig->real_timer)) |
841 | hrtimer_restart(&sig->real_timer); | |
932aeafb | 842 | spin_lock_irq(lock); |
53231250 | 843 | } |
1da177e4 | 844 | while (atomic_read(&sig->count) > count) { |
aafe6c2a | 845 | sig->group_exit_task = tsk; |
1da177e4 LT |
846 | sig->notify_count = count; |
847 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
848 | spin_unlock_irq(lock); | |
849 | schedule(); | |
850 | spin_lock_irq(lock); | |
851 | } | |
852 | sig->group_exit_task = NULL; | |
853 | sig->notify_count = 0; | |
854 | spin_unlock_irq(lock); | |
855 | ||
856 | /* | |
857 | * At this point all other threads have exited, all we have to | |
858 | * do is to wait for the thread group leader to become inactive, | |
859 | * and to assume its PID: | |
860 | */ | |
aafe6c2a | 861 | if (!thread_group_leader(tsk)) { |
1da177e4 LT |
862 | /* |
863 | * Wait for the thread group leader to be a zombie. | |
864 | * It should already be zombie at this point, most | |
865 | * of the time. | |
866 | */ | |
aafe6c2a | 867 | leader = tsk->group_leader; |
1da177e4 LT |
868 | while (leader->exit_state != EXIT_ZOMBIE) |
869 | yield(); | |
870 | ||
f5e90281 RM |
871 | /* |
872 | * The only record we have of the real-time age of a | |
873 | * process, regardless of execs it's done, is start_time. | |
874 | * All the past CPU time is accumulated in signal_struct | |
875 | * from sister threads now dead. But in this non-leader | |
876 | * exec, nothing survives from the original leader thread, | |
877 | * whose birth marks the true age of this process now. | |
878 | * When we take on its identity by switching to its PID, we | |
879 | * also take its birthdate (always earlier than our own). | |
880 | */ | |
aafe6c2a | 881 | tsk->start_time = leader->start_time; |
f5e90281 | 882 | |
1da177e4 LT |
883 | write_lock_irq(&tasklist_lock); |
884 | ||
aafe6c2a EB |
885 | BUG_ON(leader->tgid != tsk->tgid); |
886 | BUG_ON(tsk->pid == tsk->tgid); | |
1da177e4 LT |
887 | /* |
888 | * An exec() starts a new thread group with the | |
889 | * TGID of the previous thread group. Rehash the | |
890 | * two threads with a switched PID, and release | |
891 | * the former thread group leader: | |
892 | */ | |
d73d6529 EB |
893 | |
894 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
895 | * The old leader becomes a thread of the this thread group. |
896 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
897 | * is called. Odd but simple and correct. |
898 | */ | |
aafe6c2a EB |
899 | detach_pid(tsk, PIDTYPE_PID); |
900 | tsk->pid = leader->pid; | |
e713d0da | 901 | attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid)); |
aafe6c2a EB |
902 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
903 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
904 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 905 | |
aafe6c2a EB |
906 | tsk->group_leader = tsk; |
907 | leader->group_leader = tsk; | |
de12a787 | 908 | |
aafe6c2a | 909 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
910 | |
911 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
912 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
913 | |
914 | write_unlock_irq(&tasklist_lock); | |
1da177e4 LT |
915 | } |
916 | ||
917 | /* | |
fb085cf1 AN |
918 | * There may be one thread left which is just exiting, |
919 | * but it's safe to stop telling the group to kill themselves. | |
1da177e4 LT |
920 | */ |
921 | sig->flags = 0; | |
922 | ||
923 | no_thread_group: | |
1da177e4 | 924 | exit_itimers(sig); |
329f7dba ON |
925 | if (leader) |
926 | release_task(leader); | |
927 | ||
1da177e4 LT |
928 | if (atomic_read(&oldsighand->count) == 1) { |
929 | /* | |
930 | * Now that we nuked the rest of the thread group, | |
931 | * it turns out we are not sharing sighand any more either. | |
932 | * So we can just keep it. | |
933 | */ | |
934 | kmem_cache_free(sighand_cachep, newsighand); | |
935 | } else { | |
936 | /* | |
937 | * Move our state over to newsighand and switch it in. | |
938 | */ | |
1da177e4 LT |
939 | atomic_set(&newsighand->count, 1); |
940 | memcpy(newsighand->action, oldsighand->action, | |
941 | sizeof(newsighand->action)); | |
942 | ||
943 | write_lock_irq(&tasklist_lock); | |
944 | spin_lock(&oldsighand->siglock); | |
513627d7 | 945 | spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING); |
1da177e4 | 946 | |
aafe6c2a | 947 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
948 | recalc_sigpending(); |
949 | ||
950 | spin_unlock(&newsighand->siglock); | |
951 | spin_unlock(&oldsighand->siglock); | |
952 | write_unlock_irq(&tasklist_lock); | |
953 | ||
fba2afaa | 954 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
955 | } |
956 | ||
aafe6c2a | 957 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
958 | return 0; |
959 | } | |
960 | ||
961 | /* | |
962 | * These functions flushes out all traces of the currently running executable | |
963 | * so that a new one can be started | |
964 | */ | |
965 | ||
858119e1 | 966 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
967 | { |
968 | long j = -1; | |
badf1662 | 969 | struct fdtable *fdt; |
1da177e4 LT |
970 | |
971 | spin_lock(&files->file_lock); | |
972 | for (;;) { | |
973 | unsigned long set, i; | |
974 | ||
975 | j++; | |
976 | i = j * __NFDBITS; | |
badf1662 | 977 | fdt = files_fdtable(files); |
bbea9f69 | 978 | if (i >= fdt->max_fds) |
1da177e4 | 979 | break; |
badf1662 | 980 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
981 | if (!set) |
982 | continue; | |
badf1662 | 983 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
984 | spin_unlock(&files->file_lock); |
985 | for ( ; set ; i++,set >>= 1) { | |
986 | if (set & 1) { | |
987 | sys_close(i); | |
988 | } | |
989 | } | |
990 | spin_lock(&files->file_lock); | |
991 | ||
992 | } | |
993 | spin_unlock(&files->file_lock); | |
994 | } | |
995 | ||
996 | void get_task_comm(char *buf, struct task_struct *tsk) | |
997 | { | |
998 | /* buf must be at least sizeof(tsk->comm) in size */ | |
999 | task_lock(tsk); | |
1000 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1001 | task_unlock(tsk); | |
1002 | } | |
1003 | ||
1004 | void set_task_comm(struct task_struct *tsk, char *buf) | |
1005 | { | |
1006 | task_lock(tsk); | |
1007 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
1008 | task_unlock(tsk); | |
1009 | } | |
1010 | ||
1011 | int flush_old_exec(struct linux_binprm * bprm) | |
1012 | { | |
1013 | char * name; | |
1014 | int i, ch, retval; | |
1015 | struct files_struct *files; | |
1016 | char tcomm[sizeof(current->comm)]; | |
1017 | ||
1018 | /* | |
1019 | * Make sure we have a private signal table and that | |
1020 | * we are unassociated from the previous thread group. | |
1021 | */ | |
1022 | retval = de_thread(current); | |
1023 | if (retval) | |
1024 | goto out; | |
1025 | ||
1026 | /* | |
1027 | * Make sure we have private file handles. Ask the | |
1028 | * fork helper to do the work for us and the exit | |
1029 | * helper to do the cleanup of the old one. | |
1030 | */ | |
1031 | files = current->files; /* refcounted so safe to hold */ | |
1032 | retval = unshare_files(); | |
1033 | if (retval) | |
1034 | goto out; | |
1035 | /* | |
1036 | * Release all of the old mmap stuff | |
1037 | */ | |
1038 | retval = exec_mmap(bprm->mm); | |
1039 | if (retval) | |
1040 | goto mmap_failed; | |
1041 | ||
1042 | bprm->mm = NULL; /* We're using it now */ | |
1043 | ||
1044 | /* This is the point of no return */ | |
1da177e4 LT |
1045 | put_files_struct(files); |
1046 | ||
1047 | current->sas_ss_sp = current->sas_ss_size = 0; | |
1048 | ||
1049 | if (current->euid == current->uid && current->egid == current->gid) | |
6c5d5238 | 1050 | set_dumpable(current->mm, 1); |
d6e71144 | 1051 | else |
6c5d5238 | 1052 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1053 | |
1da177e4 | 1054 | name = bprm->filename; |
36772092 PBG |
1055 | |
1056 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
1057 | for (i=0; (ch = *(name++)) != '\0';) { |
1058 | if (ch == '/') | |
36772092 | 1059 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
1060 | else |
1061 | if (i < (sizeof(tcomm) - 1)) | |
1062 | tcomm[i++] = ch; | |
1063 | } | |
1064 | tcomm[i] = '\0'; | |
1065 | set_task_comm(current, tcomm); | |
1066 | ||
1067 | current->flags &= ~PF_RANDOMIZE; | |
1068 | flush_thread(); | |
1069 | ||
0551fbd2 BH |
1070 | /* Set the new mm task size. We have to do that late because it may |
1071 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1072 | * some architectures like powerpc | |
1073 | */ | |
1074 | current->mm->task_size = TASK_SIZE; | |
1075 | ||
d2d56c5f MH |
1076 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { |
1077 | suid_keys(current); | |
1078 | set_dumpable(current->mm, suid_dumpable); | |
1079 | current->pdeath_signal = 0; | |
1080 | } else if (file_permission(bprm->file, MAY_READ) || | |
1081 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
1da177e4 | 1082 | suid_keys(current); |
6c5d5238 | 1083 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1084 | } |
1085 | ||
1086 | /* An exec changes our domain. We are no longer part of the thread | |
1087 | group */ | |
1088 | ||
1089 | current->self_exec_id++; | |
1090 | ||
1091 | flush_signal_handlers(current, 0); | |
1092 | flush_old_files(current->files); | |
1093 | ||
1094 | return 0; | |
1095 | ||
1096 | mmap_failed: | |
3b9b8ab6 | 1097 | reset_files_struct(current, files); |
1da177e4 LT |
1098 | out: |
1099 | return retval; | |
1100 | } | |
1101 | ||
1102 | EXPORT_SYMBOL(flush_old_exec); | |
1103 | ||
1104 | /* | |
1105 | * Fill the binprm structure from the inode. | |
1106 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1107 | */ | |
1108 | int prepare_binprm(struct linux_binprm *bprm) | |
1109 | { | |
1110 | int mode; | |
0f7fc9e4 | 1111 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1112 | int retval; |
1113 | ||
1114 | mode = inode->i_mode; | |
1da177e4 LT |
1115 | if (bprm->file->f_op == NULL) |
1116 | return -EACCES; | |
1117 | ||
1118 | bprm->e_uid = current->euid; | |
1119 | bprm->e_gid = current->egid; | |
1120 | ||
0f7fc9e4 | 1121 | if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1122 | /* Set-uid? */ |
1123 | if (mode & S_ISUID) { | |
1124 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1125 | bprm->e_uid = inode->i_uid; | |
1126 | } | |
1127 | ||
1128 | /* Set-gid? */ | |
1129 | /* | |
1130 | * If setgid is set but no group execute bit then this | |
1131 | * is a candidate for mandatory locking, not a setgid | |
1132 | * executable. | |
1133 | */ | |
1134 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1135 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1136 | bprm->e_gid = inode->i_gid; | |
1137 | } | |
1138 | } | |
1139 | ||
1140 | /* fill in binprm security blob */ | |
1141 | retval = security_bprm_set(bprm); | |
1142 | if (retval) | |
1143 | return retval; | |
1144 | ||
1145 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
1146 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
1147 | } | |
1148 | ||
1149 | EXPORT_SYMBOL(prepare_binprm); | |
1150 | ||
858119e1 | 1151 | static int unsafe_exec(struct task_struct *p) |
1da177e4 LT |
1152 | { |
1153 | int unsafe = 0; | |
1154 | if (p->ptrace & PT_PTRACED) { | |
1155 | if (p->ptrace & PT_PTRACE_CAP) | |
1156 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1157 | else | |
1158 | unsafe |= LSM_UNSAFE_PTRACE; | |
1159 | } | |
1160 | if (atomic_read(&p->fs->count) > 1 || | |
1161 | atomic_read(&p->files->count) > 1 || | |
1162 | atomic_read(&p->sighand->count) > 1) | |
1163 | unsafe |= LSM_UNSAFE_SHARE; | |
1164 | ||
1165 | return unsafe; | |
1166 | } | |
1167 | ||
1168 | void compute_creds(struct linux_binprm *bprm) | |
1169 | { | |
1170 | int unsafe; | |
1171 | ||
d2d56c5f | 1172 | if (bprm->e_uid != current->uid) { |
1da177e4 | 1173 | suid_keys(current); |
d2d56c5f MH |
1174 | current->pdeath_signal = 0; |
1175 | } | |
1da177e4 LT |
1176 | exec_keys(current); |
1177 | ||
1178 | task_lock(current); | |
1179 | unsafe = unsafe_exec(current); | |
1180 | security_bprm_apply_creds(bprm, unsafe); | |
1181 | task_unlock(current); | |
1182 | security_bprm_post_apply_creds(bprm); | |
1183 | } | |
1da177e4 LT |
1184 | EXPORT_SYMBOL(compute_creds); |
1185 | ||
4fc75ff4 NP |
1186 | /* |
1187 | * Arguments are '\0' separated strings found at the location bprm->p | |
1188 | * points to; chop off the first by relocating brpm->p to right after | |
1189 | * the first '\0' encountered. | |
1190 | */ | |
b6a2fea3 | 1191 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1192 | { |
b6a2fea3 OW |
1193 | int ret = 0; |
1194 | unsigned long offset; | |
1195 | char *kaddr; | |
1196 | struct page *page; | |
4fc75ff4 | 1197 | |
b6a2fea3 OW |
1198 | if (!bprm->argc) |
1199 | return 0; | |
1da177e4 | 1200 | |
b6a2fea3 OW |
1201 | do { |
1202 | offset = bprm->p & ~PAGE_MASK; | |
1203 | page = get_arg_page(bprm, bprm->p, 0); | |
1204 | if (!page) { | |
1205 | ret = -EFAULT; | |
1206 | goto out; | |
1207 | } | |
1208 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1209 | |
b6a2fea3 OW |
1210 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1211 | offset++, bprm->p++) | |
1212 | ; | |
4fc75ff4 | 1213 | |
b6a2fea3 OW |
1214 | kunmap_atomic(kaddr, KM_USER0); |
1215 | put_arg_page(page); | |
4fc75ff4 | 1216 | |
b6a2fea3 OW |
1217 | if (offset == PAGE_SIZE) |
1218 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1219 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1220 | |
b6a2fea3 OW |
1221 | bprm->p++; |
1222 | bprm->argc--; | |
1223 | ret = 0; | |
4fc75ff4 | 1224 | |
b6a2fea3 OW |
1225 | out: |
1226 | return ret; | |
1da177e4 | 1227 | } |
1da177e4 LT |
1228 | EXPORT_SYMBOL(remove_arg_zero); |
1229 | ||
1230 | /* | |
1231 | * cycle the list of binary formats handler, until one recognizes the image | |
1232 | */ | |
1233 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1234 | { | |
1235 | int try,retval; | |
1236 | struct linux_binfmt *fmt; | |
1237 | #ifdef __alpha__ | |
1238 | /* handle /sbin/loader.. */ | |
1239 | { | |
1240 | struct exec * eh = (struct exec *) bprm->buf; | |
1241 | ||
1242 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1243 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1244 | { | |
1245 | struct file * file; | |
1246 | unsigned long loader; | |
1247 | ||
1248 | allow_write_access(bprm->file); | |
1249 | fput(bprm->file); | |
1250 | bprm->file = NULL; | |
1251 | ||
b6a2fea3 | 1252 | loader = bprm->vma->vm_end - sizeof(void *); |
1da177e4 LT |
1253 | |
1254 | file = open_exec("/sbin/loader"); | |
1255 | retval = PTR_ERR(file); | |
1256 | if (IS_ERR(file)) | |
1257 | return retval; | |
1258 | ||
1259 | /* Remember if the application is TASO. */ | |
1260 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1261 | ||
1262 | bprm->file = file; | |
1263 | bprm->loader = loader; | |
1264 | retval = prepare_binprm(bprm); | |
1265 | if (retval<0) | |
1266 | return retval; | |
1267 | /* should call search_binary_handler recursively here, | |
1268 | but it does not matter */ | |
1269 | } | |
1270 | } | |
1271 | #endif | |
1272 | retval = security_bprm_check(bprm); | |
1273 | if (retval) | |
1274 | return retval; | |
1275 | ||
1276 | /* kernel module loader fixup */ | |
1277 | /* so we don't try to load run modprobe in kernel space. */ | |
1278 | set_fs(USER_DS); | |
473ae30b AV |
1279 | |
1280 | retval = audit_bprm(bprm); | |
1281 | if (retval) | |
1282 | return retval; | |
1283 | ||
1da177e4 LT |
1284 | retval = -ENOENT; |
1285 | for (try=0; try<2; try++) { | |
1286 | read_lock(&binfmt_lock); | |
1287 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
1288 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; | |
1289 | if (!fn) | |
1290 | continue; | |
1291 | if (!try_module_get(fmt->module)) | |
1292 | continue; | |
1293 | read_unlock(&binfmt_lock); | |
1294 | retval = fn(bprm, regs); | |
1295 | if (retval >= 0) { | |
1296 | put_binfmt(fmt); | |
1297 | allow_write_access(bprm->file); | |
1298 | if (bprm->file) | |
1299 | fput(bprm->file); | |
1300 | bprm->file = NULL; | |
1301 | current->did_exec = 1; | |
9f46080c | 1302 | proc_exec_connector(current); |
1da177e4 LT |
1303 | return retval; |
1304 | } | |
1305 | read_lock(&binfmt_lock); | |
1306 | put_binfmt(fmt); | |
1307 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1308 | break; | |
1309 | if (!bprm->file) { | |
1310 | read_unlock(&binfmt_lock); | |
1311 | return retval; | |
1312 | } | |
1313 | } | |
1314 | read_unlock(&binfmt_lock); | |
1315 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1316 | break; | |
1317 | #ifdef CONFIG_KMOD | |
1318 | }else{ | |
1319 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1320 | if (printable(bprm->buf[0]) && | |
1321 | printable(bprm->buf[1]) && | |
1322 | printable(bprm->buf[2]) && | |
1323 | printable(bprm->buf[3])) | |
1324 | break; /* -ENOEXEC */ | |
1325 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1326 | #endif | |
1327 | } | |
1328 | } | |
1329 | return retval; | |
1330 | } | |
1331 | ||
1332 | EXPORT_SYMBOL(search_binary_handler); | |
1333 | ||
1334 | /* | |
1335 | * sys_execve() executes a new program. | |
1336 | */ | |
1337 | int do_execve(char * filename, | |
1338 | char __user *__user *argv, | |
1339 | char __user *__user *envp, | |
1340 | struct pt_regs * regs) | |
1341 | { | |
1342 | struct linux_binprm *bprm; | |
1343 | struct file *file; | |
bdf4c48a | 1344 | unsigned long env_p; |
1da177e4 | 1345 | int retval; |
1da177e4 LT |
1346 | |
1347 | retval = -ENOMEM; | |
11b0b5ab | 1348 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 LT |
1349 | if (!bprm) |
1350 | goto out_ret; | |
1da177e4 LT |
1351 | |
1352 | file = open_exec(filename); | |
1353 | retval = PTR_ERR(file); | |
1354 | if (IS_ERR(file)) | |
1355 | goto out_kfree; | |
1356 | ||
1357 | sched_exec(); | |
1358 | ||
1da177e4 LT |
1359 | bprm->file = file; |
1360 | bprm->filename = filename; | |
1361 | bprm->interp = filename; | |
1da177e4 | 1362 | |
b6a2fea3 OW |
1363 | retval = bprm_mm_init(bprm); |
1364 | if (retval) | |
1365 | goto out_file; | |
1da177e4 | 1366 | |
b6a2fea3 | 1367 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 LT |
1368 | if ((retval = bprm->argc) < 0) |
1369 | goto out_mm; | |
1370 | ||
b6a2fea3 | 1371 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 LT |
1372 | if ((retval = bprm->envc) < 0) |
1373 | goto out_mm; | |
1374 | ||
1375 | retval = security_bprm_alloc(bprm); | |
1376 | if (retval) | |
1377 | goto out; | |
1378 | ||
1379 | retval = prepare_binprm(bprm); | |
1380 | if (retval < 0) | |
1381 | goto out; | |
1382 | ||
1383 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1384 | if (retval < 0) | |
1385 | goto out; | |
1386 | ||
1387 | bprm->exec = bprm->p; | |
1388 | retval = copy_strings(bprm->envc, envp, bprm); | |
1389 | if (retval < 0) | |
1390 | goto out; | |
1391 | ||
bdf4c48a | 1392 | env_p = bprm->p; |
1da177e4 LT |
1393 | retval = copy_strings(bprm->argc, argv, bprm); |
1394 | if (retval < 0) | |
1395 | goto out; | |
bdf4c48a | 1396 | bprm->argv_len = env_p - bprm->p; |
1da177e4 LT |
1397 | |
1398 | retval = search_binary_handler(bprm,regs); | |
1399 | if (retval >= 0) { | |
1da177e4 | 1400 | /* execve success */ |
b6a2fea3 | 1401 | free_arg_pages(bprm); |
1da177e4 LT |
1402 | security_bprm_free(bprm); |
1403 | acct_update_integrals(current); | |
1da177e4 LT |
1404 | kfree(bprm); |
1405 | return retval; | |
1406 | } | |
1407 | ||
1408 | out: | |
b6a2fea3 | 1409 | free_arg_pages(bprm); |
1da177e4 LT |
1410 | if (bprm->security) |
1411 | security_bprm_free(bprm); | |
1412 | ||
1413 | out_mm: | |
1414 | if (bprm->mm) | |
b6a2fea3 | 1415 | mmput (bprm->mm); |
1da177e4 LT |
1416 | |
1417 | out_file: | |
1418 | if (bprm->file) { | |
1419 | allow_write_access(bprm->file); | |
1420 | fput(bprm->file); | |
1421 | } | |
1da177e4 LT |
1422 | out_kfree: |
1423 | kfree(bprm); | |
1424 | ||
1425 | out_ret: | |
1426 | return retval; | |
1427 | } | |
1428 | ||
1429 | int set_binfmt(struct linux_binfmt *new) | |
1430 | { | |
1431 | struct linux_binfmt *old = current->binfmt; | |
1432 | ||
1433 | if (new) { | |
1434 | if (!try_module_get(new->module)) | |
1435 | return -1; | |
1436 | } | |
1437 | current->binfmt = new; | |
1438 | if (old) | |
1439 | module_put(old->module); | |
1440 | return 0; | |
1441 | } | |
1442 | ||
1443 | EXPORT_SYMBOL(set_binfmt); | |
1444 | ||
1da177e4 LT |
1445 | /* format_corename will inspect the pattern parameter, and output a |
1446 | * name into corename, which must have space for at least | |
1447 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1448 | */ | |
c4bbafda | 1449 | static int format_corename(char *corename, const char *pattern, long signr) |
1da177e4 LT |
1450 | { |
1451 | const char *pat_ptr = pattern; | |
1452 | char *out_ptr = corename; | |
1453 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1454 | int rc; | |
1455 | int pid_in_pattern = 0; | |
c4bbafda AC |
1456 | int ispipe = 0; |
1457 | ||
1458 | if (*pattern == '|') | |
1459 | ispipe = 1; | |
1da177e4 LT |
1460 | |
1461 | /* Repeat as long as we have more pattern to process and more output | |
1462 | space */ | |
1463 | while (*pat_ptr) { | |
1464 | if (*pat_ptr != '%') { | |
1465 | if (out_ptr == out_end) | |
1466 | goto out; | |
1467 | *out_ptr++ = *pat_ptr++; | |
1468 | } else { | |
1469 | switch (*++pat_ptr) { | |
1470 | case 0: | |
1471 | goto out; | |
1472 | /* Double percent, output one percent */ | |
1473 | case '%': | |
1474 | if (out_ptr == out_end) | |
1475 | goto out; | |
1476 | *out_ptr++ = '%'; | |
1477 | break; | |
1478 | /* pid */ | |
1479 | case 'p': | |
1480 | pid_in_pattern = 1; | |
1481 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1482 | "%d", current->tgid); | |
1483 | if (rc > out_end - out_ptr) | |
1484 | goto out; | |
1485 | out_ptr += rc; | |
1486 | break; | |
1487 | /* uid */ | |
1488 | case 'u': | |
1489 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1490 | "%d", current->uid); | |
1491 | if (rc > out_end - out_ptr) | |
1492 | goto out; | |
1493 | out_ptr += rc; | |
1494 | break; | |
1495 | /* gid */ | |
1496 | case 'g': | |
1497 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1498 | "%d", current->gid); | |
1499 | if (rc > out_end - out_ptr) | |
1500 | goto out; | |
1501 | out_ptr += rc; | |
1502 | break; | |
1503 | /* signal that caused the coredump */ | |
1504 | case 's': | |
1505 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1506 | "%ld", signr); | |
1507 | if (rc > out_end - out_ptr) | |
1508 | goto out; | |
1509 | out_ptr += rc; | |
1510 | break; | |
1511 | /* UNIX time of coredump */ | |
1512 | case 't': { | |
1513 | struct timeval tv; | |
1514 | do_gettimeofday(&tv); | |
1515 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1516 | "%lu", tv.tv_sec); | |
1517 | if (rc > out_end - out_ptr) | |
1518 | goto out; | |
1519 | out_ptr += rc; | |
1520 | break; | |
1521 | } | |
1522 | /* hostname */ | |
1523 | case 'h': | |
1524 | down_read(&uts_sem); | |
1525 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1526 | "%s", utsname()->nodename); |
1da177e4 LT |
1527 | up_read(&uts_sem); |
1528 | if (rc > out_end - out_ptr) | |
1529 | goto out; | |
1530 | out_ptr += rc; | |
1531 | break; | |
1532 | /* executable */ | |
1533 | case 'e': | |
1534 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1535 | "%s", current->comm); | |
1536 | if (rc > out_end - out_ptr) | |
1537 | goto out; | |
1538 | out_ptr += rc; | |
1539 | break; | |
1540 | default: | |
1541 | break; | |
1542 | } | |
1543 | ++pat_ptr; | |
1544 | } | |
1545 | } | |
1546 | /* Backward compatibility with core_uses_pid: | |
1547 | * | |
1548 | * If core_pattern does not include a %p (as is the default) | |
1549 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda AC |
1550 | * the filename. Do not do this for piped commands. */ |
1551 | if (!ispipe && !pid_in_pattern | |
1da177e4 LT |
1552 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { |
1553 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1554 | ".%d", current->tgid); | |
1555 | if (rc > out_end - out_ptr) | |
1556 | goto out; | |
1557 | out_ptr += rc; | |
1558 | } | |
c4bbafda | 1559 | out: |
1da177e4 | 1560 | *out_ptr = 0; |
c4bbafda | 1561 | return ispipe; |
1da177e4 LT |
1562 | } |
1563 | ||
d5f70c00 | 1564 | static void zap_process(struct task_struct *start) |
aceecc04 ON |
1565 | { |
1566 | struct task_struct *t; | |
281de339 | 1567 | |
d5f70c00 ON |
1568 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1569 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1570 | |
1571 | t = start; | |
1572 | do { | |
1573 | if (t != current && t->mm) { | |
1574 | t->mm->core_waiters++; | |
281de339 ON |
1575 | sigaddset(&t->pending.signal, SIGKILL); |
1576 | signal_wake_up(t, 1); | |
aceecc04 ON |
1577 | } |
1578 | } while ((t = next_thread(t)) != start); | |
1579 | } | |
1580 | ||
dcf560c5 ON |
1581 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
1582 | int exit_code) | |
1da177e4 LT |
1583 | { |
1584 | struct task_struct *g, *p; | |
5debfa6d | 1585 | unsigned long flags; |
dcf560c5 ON |
1586 | int err = -EAGAIN; |
1587 | ||
1588 | spin_lock_irq(&tsk->sighand->siglock); | |
1589 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) { | |
dcf560c5 | 1590 | tsk->signal->group_exit_code = exit_code; |
5debfa6d | 1591 | zap_process(tsk); |
dcf560c5 | 1592 | err = 0; |
1da177e4 | 1593 | } |
dcf560c5 ON |
1594 | spin_unlock_irq(&tsk->sighand->siglock); |
1595 | if (err) | |
1596 | return err; | |
1da177e4 | 1597 | |
5debfa6d ON |
1598 | if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) |
1599 | goto done; | |
1600 | ||
7b1c6154 | 1601 | rcu_read_lock(); |
aceecc04 | 1602 | for_each_process(g) { |
5debfa6d ON |
1603 | if (g == tsk->group_leader) |
1604 | continue; | |
1605 | ||
aceecc04 ON |
1606 | p = g; |
1607 | do { | |
1608 | if (p->mm) { | |
5debfa6d ON |
1609 | if (p->mm == mm) { |
1610 | /* | |
1611 | * p->sighand can't disappear, but | |
1612 | * may be changed by de_thread() | |
1613 | */ | |
1614 | lock_task_sighand(p, &flags); | |
d5f70c00 | 1615 | zap_process(p); |
5debfa6d ON |
1616 | unlock_task_sighand(p, &flags); |
1617 | } | |
aceecc04 ON |
1618 | break; |
1619 | } | |
1620 | } while ((p = next_thread(p)) != g); | |
1621 | } | |
7b1c6154 | 1622 | rcu_read_unlock(); |
5debfa6d | 1623 | done: |
dcf560c5 | 1624 | return mm->core_waiters; |
1da177e4 LT |
1625 | } |
1626 | ||
dcf560c5 | 1627 | static int coredump_wait(int exit_code) |
1da177e4 | 1628 | { |
dcf560c5 ON |
1629 | struct task_struct *tsk = current; |
1630 | struct mm_struct *mm = tsk->mm; | |
1631 | struct completion startup_done; | |
1632 | struct completion *vfork_done; | |
2384f55f | 1633 | int core_waiters; |
1da177e4 | 1634 | |
dcf560c5 ON |
1635 | init_completion(&mm->core_done); |
1636 | init_completion(&startup_done); | |
1da177e4 LT |
1637 | mm->core_startup_done = &startup_done; |
1638 | ||
dcf560c5 | 1639 | core_waiters = zap_threads(tsk, mm, exit_code); |
2384f55f ON |
1640 | up_write(&mm->mmap_sem); |
1641 | ||
dcf560c5 ON |
1642 | if (unlikely(core_waiters < 0)) |
1643 | goto fail; | |
1644 | ||
1645 | /* | |
1646 | * Make sure nobody is waiting for us to release the VM, | |
1647 | * otherwise we can deadlock when we wait on each other | |
1648 | */ | |
1649 | vfork_done = tsk->vfork_done; | |
1650 | if (vfork_done) { | |
1651 | tsk->vfork_done = NULL; | |
1652 | complete(vfork_done); | |
1653 | } | |
1654 | ||
2384f55f | 1655 | if (core_waiters) |
1da177e4 | 1656 | wait_for_completion(&startup_done); |
dcf560c5 | 1657 | fail: |
1da177e4 | 1658 | BUG_ON(mm->core_waiters); |
dcf560c5 | 1659 | return core_waiters; |
1da177e4 LT |
1660 | } |
1661 | ||
6c5d5238 KH |
1662 | /* |
1663 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1664 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1665 | * these bits are not changed atomically. So get_dumpable can observe the | |
1666 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1667 | * return either old dumpable or new one by paying attention to the order of | |
1668 | * modifying the bits. | |
1669 | * | |
1670 | * dumpable | mm->flags (binary) | |
1671 | * old new | initial interim final | |
1672 | * ---------+----------------------- | |
1673 | * 0 1 | 00 01 01 | |
1674 | * 0 2 | 00 10(*) 11 | |
1675 | * 1 0 | 01 00 00 | |
1676 | * 1 2 | 01 11 11 | |
1677 | * 2 0 | 11 10(*) 00 | |
1678 | * 2 1 | 11 11 01 | |
1679 | * | |
1680 | * (*) get_dumpable regards interim value of 10 as 11. | |
1681 | */ | |
1682 | void set_dumpable(struct mm_struct *mm, int value) | |
1683 | { | |
1684 | switch (value) { | |
1685 | case 0: | |
1686 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1687 | smp_wmb(); | |
1688 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1689 | break; | |
1690 | case 1: | |
1691 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1692 | smp_wmb(); | |
1693 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1694 | break; | |
1695 | case 2: | |
1696 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1697 | smp_wmb(); | |
1698 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1699 | break; | |
1700 | } | |
1701 | } | |
1702 | EXPORT_SYMBOL_GPL(set_dumpable); | |
1703 | ||
1704 | int get_dumpable(struct mm_struct *mm) | |
1705 | { | |
1706 | int ret; | |
1707 | ||
1708 | ret = mm->flags & 0x3; | |
1709 | return (ret >= 2) ? 2 : ret; | |
1710 | } | |
1711 | ||
1da177e4 LT |
1712 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) |
1713 | { | |
1714 | char corename[CORENAME_MAX_SIZE + 1]; | |
1715 | struct mm_struct *mm = current->mm; | |
1716 | struct linux_binfmt * binfmt; | |
1717 | struct inode * inode; | |
1718 | struct file * file; | |
1719 | int retval = 0; | |
d6e71144 AC |
1720 | int fsuid = current->fsuid; |
1721 | int flag = 0; | |
d025c9db | 1722 | int ispipe = 0; |
1da177e4 | 1723 | |
0a4ff8c2 SG |
1724 | audit_core_dumps(signr); |
1725 | ||
1da177e4 LT |
1726 | binfmt = current->binfmt; |
1727 | if (!binfmt || !binfmt->core_dump) | |
1728 | goto fail; | |
1729 | down_write(&mm->mmap_sem); | |
6c5d5238 | 1730 | if (!get_dumpable(mm)) { |
1da177e4 LT |
1731 | up_write(&mm->mmap_sem); |
1732 | goto fail; | |
1733 | } | |
d6e71144 AC |
1734 | |
1735 | /* | |
1736 | * We cannot trust fsuid as being the "true" uid of the | |
1737 | * process nor do we know its entire history. We only know it | |
1738 | * was tainted so we dump it as root in mode 2. | |
1739 | */ | |
6c5d5238 | 1740 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 AC |
1741 | flag = O_EXCL; /* Stop rewrite attacks */ |
1742 | current->fsuid = 0; /* Dump root private */ | |
1743 | } | |
6c5d5238 | 1744 | set_dumpable(mm, 0); |
1291cf41 | 1745 | |
dcf560c5 ON |
1746 | retval = coredump_wait(exit_code); |
1747 | if (retval < 0) | |
1291cf41 | 1748 | goto fail; |
1da177e4 LT |
1749 | |
1750 | /* | |
1751 | * Clear any false indication of pending signals that might | |
1752 | * be seen by the filesystem code called to write the core file. | |
1753 | */ | |
1da177e4 LT |
1754 | clear_thread_flag(TIF_SIGPENDING); |
1755 | ||
1756 | if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) | |
1757 | goto fail_unlock; | |
1758 | ||
1759 | /* | |
1760 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1761 | * uses lock_kernel() | |
1762 | */ | |
1763 | lock_kernel(); | |
c4bbafda | 1764 | ispipe = format_corename(corename, core_pattern, signr); |
1da177e4 | 1765 | unlock_kernel(); |
c4bbafda | 1766 | if (ispipe) { |
d025c9db AK |
1767 | /* SIGPIPE can happen, but it's just never processed */ |
1768 | if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) { | |
1769 | printk(KERN_INFO "Core dump to %s pipe failed\n", | |
1770 | corename); | |
1771 | goto fail_unlock; | |
1772 | } | |
d025c9db AK |
1773 | } else |
1774 | file = filp_open(corename, | |
6d4df677 AD |
1775 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1776 | 0600); | |
1da177e4 LT |
1777 | if (IS_ERR(file)) |
1778 | goto fail_unlock; | |
0f7fc9e4 | 1779 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1780 | if (inode->i_nlink > 1) |
1781 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1782 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1783 | goto close_fail; |
1784 | ||
d025c9db AK |
1785 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1786 | but keep the previous behaviour for now. */ | |
1787 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 LT |
1788 | goto close_fail; |
1789 | if (!file->f_op) | |
1790 | goto close_fail; | |
1791 | if (!file->f_op->write) | |
1792 | goto close_fail; | |
0f7fc9e4 | 1793 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1794 | goto close_fail; |
1795 | ||
1796 | retval = binfmt->core_dump(signr, regs, file); | |
1797 | ||
1798 | if (retval) | |
1799 | current->signal->group_exit_code |= 0x80; | |
1800 | close_fail: | |
1801 | filp_close(file, NULL); | |
1802 | fail_unlock: | |
d6e71144 | 1803 | current->fsuid = fsuid; |
1da177e4 LT |
1804 | complete_all(&mm->core_done); |
1805 | fail: | |
1806 | return retval; | |
1807 | } |