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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/exec.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * #!-checking implemented by tytso. | |
9 | */ | |
10 | /* | |
11 | * Demand-loading implemented 01.12.91 - no need to read anything but | |
12 | * the header into memory. The inode of the executable is put into | |
13 | * "current->executable", and page faults do the actual loading. Clean. | |
14 | * | |
15 | * Once more I can proudly say that linux stood up to being changed: it | |
16 | * was less than 2 hours work to get demand-loading completely implemented. | |
17 | * | |
18 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, | |
19 | * current->executable is only used by the procfs. This allows a dispatch | |
20 | * table to check for several different types of binary formats. We keep | |
21 | * trying until we recognize the file or we run out of supported binary | |
22 | * formats. | |
23 | */ | |
24 | ||
1da177e4 LT |
25 | #include <linux/slab.h> |
26 | #include <linux/file.h> | |
9f3acc31 | 27 | #include <linux/fdtable.h> |
ba92a43d | 28 | #include <linux/mm.h> |
1da177e4 LT |
29 | #include <linux/stat.h> |
30 | #include <linux/fcntl.h> | |
31 | #include <linux/smp_lock.h> | |
ba92a43d | 32 | #include <linux/swap.h> |
74aadce9 | 33 | #include <linux/string.h> |
1da177e4 | 34 | #include <linux/init.h> |
ca5b172b | 35 | #include <linux/pagemap.h> |
1da177e4 LT |
36 | #include <linux/highmem.h> |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/key.h> | |
39 | #include <linux/personality.h> | |
40 | #include <linux/binfmts.h> | |
1da177e4 | 41 | #include <linux/utsname.h> |
84d73786 | 42 | #include <linux/pid_namespace.h> |
1da177e4 LT |
43 | #include <linux/module.h> |
44 | #include <linux/namei.h> | |
45 | #include <linux/proc_fs.h> | |
1da177e4 LT |
46 | #include <linux/mount.h> |
47 | #include <linux/security.h> | |
6146f0d5 | 48 | #include <linux/ima.h> |
1da177e4 | 49 | #include <linux/syscalls.h> |
8f0ab514 | 50 | #include <linux/tsacct_kern.h> |
9f46080c | 51 | #include <linux/cn_proc.h> |
473ae30b | 52 | #include <linux/audit.h> |
6341c393 | 53 | #include <linux/tracehook.h> |
5f4123be | 54 | #include <linux/kmod.h> |
6110e3ab | 55 | #include <linux/fsnotify.h> |
1da177e4 LT |
56 | |
57 | #include <asm/uaccess.h> | |
58 | #include <asm/mmu_context.h> | |
b6a2fea3 | 59 | #include <asm/tlb.h> |
a6f76f23 | 60 | #include "internal.h" |
1da177e4 | 61 | |
1da177e4 | 62 | int core_uses_pid; |
71ce92f3 | 63 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
d6e71144 AC |
64 | int suid_dumpable = 0; |
65 | ||
1da177e4 LT |
66 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
67 | ||
e4dc1b14 | 68 | static LIST_HEAD(formats); |
1da177e4 LT |
69 | static DEFINE_RWLOCK(binfmt_lock); |
70 | ||
71 | int register_binfmt(struct linux_binfmt * fmt) | |
72 | { | |
1da177e4 LT |
73 | if (!fmt) |
74 | return -EINVAL; | |
1da177e4 | 75 | write_lock(&binfmt_lock); |
e4dc1b14 | 76 | list_add(&fmt->lh, &formats); |
1da177e4 LT |
77 | write_unlock(&binfmt_lock); |
78 | return 0; | |
79 | } | |
80 | ||
81 | EXPORT_SYMBOL(register_binfmt); | |
82 | ||
f6b450d4 | 83 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 84 | { |
1da177e4 | 85 | write_lock(&binfmt_lock); |
e4dc1b14 | 86 | list_del(&fmt->lh); |
1da177e4 | 87 | write_unlock(&binfmt_lock); |
1da177e4 LT |
88 | } |
89 | ||
90 | EXPORT_SYMBOL(unregister_binfmt); | |
91 | ||
92 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
93 | { | |
94 | module_put(fmt->module); | |
95 | } | |
96 | ||
97 | /* | |
98 | * Note that a shared library must be both readable and executable due to | |
99 | * security reasons. | |
100 | * | |
101 | * Also note that we take the address to load from from the file itself. | |
102 | */ | |
1e7bfb21 | 103 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 104 | { |
964bd183 | 105 | struct file *file; |
1da177e4 | 106 | struct nameidata nd; |
964bd183 AV |
107 | char *tmp = getname(library); |
108 | int error = PTR_ERR(tmp); | |
109 | ||
110 | if (!IS_ERR(tmp)) { | |
111 | error = path_lookup_open(AT_FDCWD, tmp, | |
112 | LOOKUP_FOLLOW, &nd, | |
113 | FMODE_READ|FMODE_EXEC); | |
114 | putname(tmp); | |
115 | } | |
1da177e4 LT |
116 | if (error) |
117 | goto out; | |
118 | ||
119 | error = -EINVAL; | |
4ac91378 | 120 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) |
1da177e4 LT |
121 | goto exit; |
122 | ||
30524472 AV |
123 | error = -EACCES; |
124 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) | |
125 | goto exit; | |
126 | ||
cb23beb5 CH |
127 | error = inode_permission(nd.path.dentry->d_inode, |
128 | MAY_READ | MAY_EXEC | MAY_OPEN); | |
6146f0d5 MZ |
129 | if (error) |
130 | goto exit; | |
131 | error = ima_path_check(&nd.path, MAY_READ | MAY_EXEC | MAY_OPEN); | |
1da177e4 LT |
132 | if (error) |
133 | goto exit; | |
134 | ||
abe8be3a | 135 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); |
1da177e4 LT |
136 | error = PTR_ERR(file); |
137 | if (IS_ERR(file)) | |
138 | goto out; | |
139 | ||
6110e3ab EP |
140 | fsnotify_open(file->f_path.dentry); |
141 | ||
1da177e4 LT |
142 | error = -ENOEXEC; |
143 | if(file->f_op) { | |
144 | struct linux_binfmt * fmt; | |
145 | ||
146 | read_lock(&binfmt_lock); | |
e4dc1b14 | 147 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
148 | if (!fmt->load_shlib) |
149 | continue; | |
150 | if (!try_module_get(fmt->module)) | |
151 | continue; | |
152 | read_unlock(&binfmt_lock); | |
153 | error = fmt->load_shlib(file); | |
154 | read_lock(&binfmt_lock); | |
155 | put_binfmt(fmt); | |
156 | if (error != -ENOEXEC) | |
157 | break; | |
158 | } | |
159 | read_unlock(&binfmt_lock); | |
160 | } | |
161 | fput(file); | |
162 | out: | |
163 | return error; | |
164 | exit: | |
834f2a4a | 165 | release_open_intent(&nd); |
1d957f9b | 166 | path_put(&nd.path); |
1da177e4 LT |
167 | goto out; |
168 | } | |
169 | ||
b6a2fea3 OW |
170 | #ifdef CONFIG_MMU |
171 | ||
172 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
173 | int write) | |
174 | { | |
175 | struct page *page; | |
176 | int ret; | |
177 | ||
178 | #ifdef CONFIG_STACK_GROWSUP | |
179 | if (write) { | |
180 | ret = expand_stack_downwards(bprm->vma, pos); | |
181 | if (ret < 0) | |
182 | return NULL; | |
183 | } | |
184 | #endif | |
185 | ret = get_user_pages(current, bprm->mm, pos, | |
186 | 1, write, 1, &page, NULL); | |
187 | if (ret <= 0) | |
188 | return NULL; | |
189 | ||
190 | if (write) { | |
b6a2fea3 | 191 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
192 | struct rlimit *rlim; |
193 | ||
194 | /* | |
195 | * We've historically supported up to 32 pages (ARG_MAX) | |
196 | * of argument strings even with small stacks | |
197 | */ | |
198 | if (size <= ARG_MAX) | |
199 | return page; | |
b6a2fea3 OW |
200 | |
201 | /* | |
202 | * Limit to 1/4-th the stack size for the argv+env strings. | |
203 | * This ensures that: | |
204 | * - the remaining binfmt code will not run out of stack space, | |
205 | * - the program will have a reasonable amount of stack left | |
206 | * to work from. | |
207 | */ | |
a64e715f | 208 | rlim = current->signal->rlim; |
b6a2fea3 OW |
209 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { |
210 | put_page(page); | |
211 | return NULL; | |
212 | } | |
213 | } | |
214 | ||
215 | return page; | |
216 | } | |
217 | ||
218 | static void put_arg_page(struct page *page) | |
219 | { | |
220 | put_page(page); | |
221 | } | |
222 | ||
223 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
224 | { | |
225 | } | |
226 | ||
227 | static void free_arg_pages(struct linux_binprm *bprm) | |
228 | { | |
229 | } | |
230 | ||
231 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
232 | struct page *page) | |
233 | { | |
234 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
235 | } | |
236 | ||
237 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
238 | { | |
eaccbfa5 | 239 | int err; |
b6a2fea3 OW |
240 | struct vm_area_struct *vma = NULL; |
241 | struct mm_struct *mm = bprm->mm; | |
242 | ||
243 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
244 | if (!vma) | |
eaccbfa5 | 245 | return -ENOMEM; |
b6a2fea3 OW |
246 | |
247 | down_write(&mm->mmap_sem); | |
248 | vma->vm_mm = mm; | |
249 | ||
250 | /* | |
251 | * Place the stack at the largest stack address the architecture | |
252 | * supports. Later, we'll move this to an appropriate place. We don't | |
253 | * use STACK_TOP because that can depend on attributes which aren't | |
254 | * configured yet. | |
255 | */ | |
256 | vma->vm_end = STACK_TOP_MAX; | |
257 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
b6a2fea3 | 258 | vma->vm_flags = VM_STACK_FLAGS; |
3ed75eb8 | 259 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
b6a2fea3 | 260 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 261 | if (err) |
b6a2fea3 | 262 | goto err; |
b6a2fea3 OW |
263 | |
264 | mm->stack_vm = mm->total_vm = 1; | |
265 | up_write(&mm->mmap_sem); | |
b6a2fea3 | 266 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 267 | return 0; |
b6a2fea3 | 268 | err: |
eaccbfa5 LFC |
269 | up_write(&mm->mmap_sem); |
270 | bprm->vma = NULL; | |
271 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
272 | return err; |
273 | } | |
274 | ||
275 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
276 | { | |
277 | return len <= MAX_ARG_STRLEN; | |
278 | } | |
279 | ||
280 | #else | |
281 | ||
282 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
283 | int write) | |
284 | { | |
285 | struct page *page; | |
286 | ||
287 | page = bprm->page[pos / PAGE_SIZE]; | |
288 | if (!page && write) { | |
289 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
290 | if (!page) | |
291 | return NULL; | |
292 | bprm->page[pos / PAGE_SIZE] = page; | |
293 | } | |
294 | ||
295 | return page; | |
296 | } | |
297 | ||
298 | static void put_arg_page(struct page *page) | |
299 | { | |
300 | } | |
301 | ||
302 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
303 | { | |
304 | if (bprm->page[i]) { | |
305 | __free_page(bprm->page[i]); | |
306 | bprm->page[i] = NULL; | |
307 | } | |
308 | } | |
309 | ||
310 | static void free_arg_pages(struct linux_binprm *bprm) | |
311 | { | |
312 | int i; | |
313 | ||
314 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
315 | free_arg_page(bprm, i); | |
316 | } | |
317 | ||
318 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
319 | struct page *page) | |
320 | { | |
321 | } | |
322 | ||
323 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
324 | { | |
325 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
326 | return 0; | |
327 | } | |
328 | ||
329 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
330 | { | |
331 | return len <= bprm->p; | |
332 | } | |
333 | ||
334 | #endif /* CONFIG_MMU */ | |
335 | ||
336 | /* | |
337 | * Create a new mm_struct and populate it with a temporary stack | |
338 | * vm_area_struct. We don't have enough context at this point to set the stack | |
339 | * flags, permissions, and offset, so we use temporary values. We'll update | |
340 | * them later in setup_arg_pages(). | |
341 | */ | |
342 | int bprm_mm_init(struct linux_binprm *bprm) | |
343 | { | |
344 | int err; | |
345 | struct mm_struct *mm = NULL; | |
346 | ||
347 | bprm->mm = mm = mm_alloc(); | |
348 | err = -ENOMEM; | |
349 | if (!mm) | |
350 | goto err; | |
351 | ||
352 | err = init_new_context(current, mm); | |
353 | if (err) | |
354 | goto err; | |
355 | ||
356 | err = __bprm_mm_init(bprm); | |
357 | if (err) | |
358 | goto err; | |
359 | ||
360 | return 0; | |
361 | ||
362 | err: | |
363 | if (mm) { | |
364 | bprm->mm = NULL; | |
365 | mmdrop(mm); | |
366 | } | |
367 | ||
368 | return err; | |
369 | } | |
370 | ||
1da177e4 LT |
371 | /* |
372 | * count() counts the number of strings in array ARGV. | |
373 | */ | |
374 | static int count(char __user * __user * argv, int max) | |
375 | { | |
376 | int i = 0; | |
377 | ||
378 | if (argv != NULL) { | |
379 | for (;;) { | |
380 | char __user * p; | |
381 | ||
382 | if (get_user(p, argv)) | |
383 | return -EFAULT; | |
384 | if (!p) | |
385 | break; | |
386 | argv++; | |
362e6663 | 387 | if (i++ >= max) |
1da177e4 LT |
388 | return -E2BIG; |
389 | cond_resched(); | |
390 | } | |
391 | } | |
392 | return i; | |
393 | } | |
394 | ||
395 | /* | |
b6a2fea3 OW |
396 | * 'copy_strings()' copies argument/environment strings from the old |
397 | * processes's memory to the new process's stack. The call to get_user_pages() | |
398 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 399 | */ |
75c96f85 AB |
400 | static int copy_strings(int argc, char __user * __user * argv, |
401 | struct linux_binprm *bprm) | |
1da177e4 LT |
402 | { |
403 | struct page *kmapped_page = NULL; | |
404 | char *kaddr = NULL; | |
b6a2fea3 | 405 | unsigned long kpos = 0; |
1da177e4 LT |
406 | int ret; |
407 | ||
408 | while (argc-- > 0) { | |
409 | char __user *str; | |
410 | int len; | |
411 | unsigned long pos; | |
412 | ||
413 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 414 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
415 | ret = -EFAULT; |
416 | goto out; | |
417 | } | |
418 | ||
b6a2fea3 | 419 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
420 | ret = -E2BIG; |
421 | goto out; | |
422 | } | |
423 | ||
b6a2fea3 | 424 | /* We're going to work our way backwords. */ |
1da177e4 | 425 | pos = bprm->p; |
b6a2fea3 OW |
426 | str += len; |
427 | bprm->p -= len; | |
1da177e4 LT |
428 | |
429 | while (len > 0) { | |
1da177e4 | 430 | int offset, bytes_to_copy; |
1da177e4 LT |
431 | |
432 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
433 | if (offset == 0) |
434 | offset = PAGE_SIZE; | |
435 | ||
436 | bytes_to_copy = offset; | |
437 | if (bytes_to_copy > len) | |
438 | bytes_to_copy = len; | |
439 | ||
440 | offset -= bytes_to_copy; | |
441 | pos -= bytes_to_copy; | |
442 | str -= bytes_to_copy; | |
443 | len -= bytes_to_copy; | |
444 | ||
445 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
446 | struct page *page; | |
447 | ||
448 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 449 | if (!page) { |
b6a2fea3 | 450 | ret = -E2BIG; |
1da177e4 LT |
451 | goto out; |
452 | } | |
1da177e4 | 453 | |
b6a2fea3 OW |
454 | if (kmapped_page) { |
455 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 456 | kunmap(kmapped_page); |
b6a2fea3 OW |
457 | put_arg_page(kmapped_page); |
458 | } | |
1da177e4 LT |
459 | kmapped_page = page; |
460 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
461 | kpos = pos & PAGE_MASK; |
462 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 463 | } |
b6a2fea3 | 464 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
465 | ret = -EFAULT; |
466 | goto out; | |
467 | } | |
1da177e4 LT |
468 | } |
469 | } | |
470 | ret = 0; | |
471 | out: | |
b6a2fea3 OW |
472 | if (kmapped_page) { |
473 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 474 | kunmap(kmapped_page); |
b6a2fea3 OW |
475 | put_arg_page(kmapped_page); |
476 | } | |
1da177e4 LT |
477 | return ret; |
478 | } | |
479 | ||
480 | /* | |
481 | * Like copy_strings, but get argv and its values from kernel memory. | |
482 | */ | |
483 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
484 | { | |
485 | int r; | |
486 | mm_segment_t oldfs = get_fs(); | |
487 | set_fs(KERNEL_DS); | |
488 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
489 | set_fs(oldfs); | |
490 | return r; | |
491 | } | |
1da177e4 LT |
492 | EXPORT_SYMBOL(copy_strings_kernel); |
493 | ||
494 | #ifdef CONFIG_MMU | |
b6a2fea3 | 495 | |
1da177e4 | 496 | /* |
b6a2fea3 OW |
497 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
498 | * the binfmt code determines where the new stack should reside, we shift it to | |
499 | * its final location. The process proceeds as follows: | |
1da177e4 | 500 | * |
b6a2fea3 OW |
501 | * 1) Use shift to calculate the new vma endpoints. |
502 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
503 | * arguments passed to subsequent functions are consistent. | |
504 | * 3) Move vma's page tables to the new range. | |
505 | * 4) Free up any cleared pgd range. | |
506 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 507 | */ |
b6a2fea3 | 508 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
509 | { |
510 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
511 | unsigned long old_start = vma->vm_start; |
512 | unsigned long old_end = vma->vm_end; | |
513 | unsigned long length = old_end - old_start; | |
514 | unsigned long new_start = old_start - shift; | |
515 | unsigned long new_end = old_end - shift; | |
516 | struct mmu_gather *tlb; | |
1da177e4 | 517 | |
b6a2fea3 | 518 | BUG_ON(new_start > new_end); |
1da177e4 | 519 | |
b6a2fea3 OW |
520 | /* |
521 | * ensure there are no vmas between where we want to go | |
522 | * and where we are | |
523 | */ | |
524 | if (vma != find_vma(mm, new_start)) | |
525 | return -EFAULT; | |
526 | ||
527 | /* | |
528 | * cover the whole range: [new_start, old_end) | |
529 | */ | |
530 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
531 | ||
532 | /* | |
533 | * move the page tables downwards, on failure we rely on | |
534 | * process cleanup to remove whatever mess we made. | |
535 | */ | |
536 | if (length != move_page_tables(vma, old_start, | |
537 | vma, new_start, length)) | |
538 | return -ENOMEM; | |
539 | ||
540 | lru_add_drain(); | |
541 | tlb = tlb_gather_mmu(mm, 0); | |
542 | if (new_end > old_start) { | |
543 | /* | |
544 | * when the old and new regions overlap clear from new_end. | |
545 | */ | |
42b77728 | 546 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
547 | vma->vm_next ? vma->vm_next->vm_start : 0); |
548 | } else { | |
549 | /* | |
550 | * otherwise, clean from old_start; this is done to not touch | |
551 | * the address space in [new_end, old_start) some architectures | |
552 | * have constraints on va-space that make this illegal (IA64) - | |
553 | * for the others its just a little faster. | |
554 | */ | |
42b77728 | 555 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 556 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 557 | } |
b6a2fea3 OW |
558 | tlb_finish_mmu(tlb, new_end, old_end); |
559 | ||
560 | /* | |
561 | * shrink the vma to just the new range. | |
562 | */ | |
563 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
564 | ||
565 | return 0; | |
1da177e4 LT |
566 | } |
567 | ||
568 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
569 | ||
b6a2fea3 OW |
570 | /* |
571 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
572 | * the stack is optionally relocated, and some extra space is added. | |
573 | */ | |
1da177e4 LT |
574 | int setup_arg_pages(struct linux_binprm *bprm, |
575 | unsigned long stack_top, | |
576 | int executable_stack) | |
577 | { | |
b6a2fea3 OW |
578 | unsigned long ret; |
579 | unsigned long stack_shift; | |
1da177e4 | 580 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
581 | struct vm_area_struct *vma = bprm->vma; |
582 | struct vm_area_struct *prev = NULL; | |
583 | unsigned long vm_flags; | |
584 | unsigned long stack_base; | |
1da177e4 LT |
585 | |
586 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
587 | /* Limit stack size to 1GB */ |
588 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
589 | if (stack_base > (1 << 30)) | |
590 | stack_base = 1 << 30; | |
1da177e4 | 591 | |
b6a2fea3 OW |
592 | /* Make sure we didn't let the argument array grow too large. */ |
593 | if (vma->vm_end - vma->vm_start > stack_base) | |
594 | return -ENOMEM; | |
1da177e4 | 595 | |
b6a2fea3 | 596 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 597 | |
b6a2fea3 OW |
598 | stack_shift = vma->vm_start - stack_base; |
599 | mm->arg_start = bprm->p - stack_shift; | |
600 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 601 | #else |
b6a2fea3 OW |
602 | stack_top = arch_align_stack(stack_top); |
603 | stack_top = PAGE_ALIGN(stack_top); | |
604 | stack_shift = vma->vm_end - stack_top; | |
605 | ||
606 | bprm->p -= stack_shift; | |
1da177e4 | 607 | mm->arg_start = bprm->p; |
1da177e4 LT |
608 | #endif |
609 | ||
1da177e4 | 610 | if (bprm->loader) |
b6a2fea3 OW |
611 | bprm->loader -= stack_shift; |
612 | bprm->exec -= stack_shift; | |
1da177e4 | 613 | |
1da177e4 | 614 | down_write(&mm->mmap_sem); |
96a8e13e | 615 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
616 | |
617 | /* | |
618 | * Adjust stack execute permissions; explicitly enable for | |
619 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
620 | * (arch default) otherwise. | |
621 | */ | |
622 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
623 | vm_flags |= VM_EXEC; | |
624 | else if (executable_stack == EXSTACK_DISABLE_X) | |
625 | vm_flags &= ~VM_EXEC; | |
626 | vm_flags |= mm->def_flags; | |
627 | ||
628 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
629 | vm_flags); | |
630 | if (ret) | |
631 | goto out_unlock; | |
632 | BUG_ON(prev != vma); | |
633 | ||
634 | /* Move stack pages down in memory. */ | |
635 | if (stack_shift) { | |
636 | ret = shift_arg_pages(vma, stack_shift); | |
637 | if (ret) { | |
1da177e4 | 638 | up_write(&mm->mmap_sem); |
1da177e4 LT |
639 | return ret; |
640 | } | |
1da177e4 LT |
641 | } |
642 | ||
b6a2fea3 OW |
643 | #ifdef CONFIG_STACK_GROWSUP |
644 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
645 | #else | |
646 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
647 | #endif | |
648 | ret = expand_stack(vma, stack_base); | |
649 | if (ret) | |
650 | ret = -EFAULT; | |
651 | ||
652 | out_unlock: | |
1da177e4 | 653 | up_write(&mm->mmap_sem); |
1da177e4 LT |
654 | return 0; |
655 | } | |
1da177e4 LT |
656 | EXPORT_SYMBOL(setup_arg_pages); |
657 | ||
1da177e4 LT |
658 | #endif /* CONFIG_MMU */ |
659 | ||
660 | struct file *open_exec(const char *name) | |
661 | { | |
662 | struct nameidata nd; | |
1da177e4 | 663 | struct file *file; |
e56b6a5d | 664 | int err; |
1da177e4 | 665 | |
e56b6a5d CH |
666 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, |
667 | FMODE_READ|FMODE_EXEC); | |
668 | if (err) | |
669 | goto out; | |
670 | ||
671 | err = -EACCES; | |
672 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) | |
673 | goto out_path_put; | |
674 | ||
30524472 AV |
675 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) |
676 | goto out_path_put; | |
677 | ||
cb23beb5 | 678 | err = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_OPEN); |
6146f0d5 MZ |
679 | if (err) |
680 | goto out_path_put; | |
681 | err = ima_path_check(&nd.path, MAY_EXEC | MAY_OPEN); | |
e56b6a5d CH |
682 | if (err) |
683 | goto out_path_put; | |
684 | ||
685 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); | |
686 | if (IS_ERR(file)) | |
687 | return file; | |
688 | ||
6110e3ab EP |
689 | fsnotify_open(file->f_path.dentry); |
690 | ||
e56b6a5d CH |
691 | err = deny_write_access(file); |
692 | if (err) { | |
693 | fput(file); | |
694 | goto out; | |
1da177e4 | 695 | } |
1da177e4 | 696 | |
e56b6a5d CH |
697 | return file; |
698 | ||
699 | out_path_put: | |
700 | release_open_intent(&nd); | |
701 | path_put(&nd.path); | |
702 | out: | |
703 | return ERR_PTR(err); | |
704 | } | |
1da177e4 LT |
705 | EXPORT_SYMBOL(open_exec); |
706 | ||
707 | int kernel_read(struct file *file, unsigned long offset, | |
708 | char *addr, unsigned long count) | |
709 | { | |
710 | mm_segment_t old_fs; | |
711 | loff_t pos = offset; | |
712 | int result; | |
713 | ||
714 | old_fs = get_fs(); | |
715 | set_fs(get_ds()); | |
716 | /* The cast to a user pointer is valid due to the set_fs() */ | |
717 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
718 | set_fs(old_fs); | |
719 | return result; | |
720 | } | |
721 | ||
722 | EXPORT_SYMBOL(kernel_read); | |
723 | ||
724 | static int exec_mmap(struct mm_struct *mm) | |
725 | { | |
726 | struct task_struct *tsk; | |
727 | struct mm_struct * old_mm, *active_mm; | |
728 | ||
729 | /* Notify parent that we're no longer interested in the old VM */ | |
730 | tsk = current; | |
731 | old_mm = current->mm; | |
732 | mm_release(tsk, old_mm); | |
733 | ||
734 | if (old_mm) { | |
735 | /* | |
736 | * Make sure that if there is a core dump in progress | |
737 | * for the old mm, we get out and die instead of going | |
738 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 739 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
740 | */ |
741 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 742 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
743 | up_read(&old_mm->mmap_sem); |
744 | return -EINTR; | |
745 | } | |
746 | } | |
747 | task_lock(tsk); | |
748 | active_mm = tsk->active_mm; | |
749 | tsk->mm = mm; | |
750 | tsk->active_mm = mm; | |
751 | activate_mm(active_mm, mm); | |
752 | task_unlock(tsk); | |
753 | arch_pick_mmap_layout(mm); | |
754 | if (old_mm) { | |
755 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 756 | BUG_ON(active_mm != old_mm); |
31a78f23 | 757 | mm_update_next_owner(old_mm); |
1da177e4 LT |
758 | mmput(old_mm); |
759 | return 0; | |
760 | } | |
761 | mmdrop(active_mm); | |
762 | return 0; | |
763 | } | |
764 | ||
765 | /* | |
766 | * This function makes sure the current process has its own signal table, | |
767 | * so that flush_signal_handlers can later reset the handlers without | |
768 | * disturbing other processes. (Other processes might share the signal | |
769 | * table via the CLONE_SIGHAND option to clone().) | |
770 | */ | |
858119e1 | 771 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
772 | { |
773 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 774 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 LT |
775 | spinlock_t *lock = &oldsighand->siglock; |
776 | int count; | |
777 | ||
aafe6c2a | 778 | if (thread_group_empty(tsk)) |
1da177e4 LT |
779 | goto no_thread_group; |
780 | ||
781 | /* | |
782 | * Kill all other threads in the thread group. | |
1da177e4 | 783 | */ |
1da177e4 | 784 | spin_lock_irq(lock); |
ed5d2cac | 785 | if (signal_group_exit(sig)) { |
1da177e4 LT |
786 | /* |
787 | * Another group action in progress, just | |
788 | * return so that the signal is processed. | |
789 | */ | |
790 | spin_unlock_irq(lock); | |
1da177e4 LT |
791 | return -EAGAIN; |
792 | } | |
ed5d2cac | 793 | sig->group_exit_task = tsk; |
aafe6c2a | 794 | zap_other_threads(tsk); |
1da177e4 | 795 | |
fea9d175 ON |
796 | /* Account for the thread group leader hanging around: */ |
797 | count = thread_group_leader(tsk) ? 1 : 2; | |
6db840fa | 798 | sig->notify_count = count; |
1da177e4 | 799 | while (atomic_read(&sig->count) > count) { |
1da177e4 LT |
800 | __set_current_state(TASK_UNINTERRUPTIBLE); |
801 | spin_unlock_irq(lock); | |
802 | schedule(); | |
803 | spin_lock_irq(lock); | |
804 | } | |
1da177e4 LT |
805 | spin_unlock_irq(lock); |
806 | ||
807 | /* | |
808 | * At this point all other threads have exited, all we have to | |
809 | * do is to wait for the thread group leader to become inactive, | |
810 | * and to assume its PID: | |
811 | */ | |
aafe6c2a | 812 | if (!thread_group_leader(tsk)) { |
8187926b | 813 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 814 | |
2800d8d1 | 815 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
816 | for (;;) { |
817 | write_lock_irq(&tasklist_lock); | |
818 | if (likely(leader->exit_state)) | |
819 | break; | |
820 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
821 | write_unlock_irq(&tasklist_lock); | |
822 | schedule(); | |
823 | } | |
1da177e4 | 824 | |
f5e90281 RM |
825 | /* |
826 | * The only record we have of the real-time age of a | |
827 | * process, regardless of execs it's done, is start_time. | |
828 | * All the past CPU time is accumulated in signal_struct | |
829 | * from sister threads now dead. But in this non-leader | |
830 | * exec, nothing survives from the original leader thread, | |
831 | * whose birth marks the true age of this process now. | |
832 | * When we take on its identity by switching to its PID, we | |
833 | * also take its birthdate (always earlier than our own). | |
834 | */ | |
aafe6c2a | 835 | tsk->start_time = leader->start_time; |
f5e90281 | 836 | |
bac0abd6 PE |
837 | BUG_ON(!same_thread_group(leader, tsk)); |
838 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
839 | /* |
840 | * An exec() starts a new thread group with the | |
841 | * TGID of the previous thread group. Rehash the | |
842 | * two threads with a switched PID, and release | |
843 | * the former thread group leader: | |
844 | */ | |
d73d6529 EB |
845 | |
846 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
847 | * The old leader becomes a thread of the this thread group. |
848 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
849 | * is called. Odd but simple and correct. |
850 | */ | |
aafe6c2a EB |
851 | detach_pid(tsk, PIDTYPE_PID); |
852 | tsk->pid = leader->pid; | |
3743ca05 | 853 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
854 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
855 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
856 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 857 | |
aafe6c2a EB |
858 | tsk->group_leader = tsk; |
859 | leader->group_leader = tsk; | |
de12a787 | 860 | |
aafe6c2a | 861 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
862 | |
863 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
864 | leader->exit_state = EXIT_DEAD; | |
1da177e4 | 865 | write_unlock_irq(&tasklist_lock); |
8187926b ON |
866 | |
867 | release_task(leader); | |
ed5d2cac | 868 | } |
1da177e4 | 869 | |
6db840fa ON |
870 | sig->group_exit_task = NULL; |
871 | sig->notify_count = 0; | |
1da177e4 LT |
872 | |
873 | no_thread_group: | |
1da177e4 | 874 | exit_itimers(sig); |
cbaffba1 | 875 | flush_itimer_signals(); |
329f7dba | 876 | |
b2c903b8 ON |
877 | if (atomic_read(&oldsighand->count) != 1) { |
878 | struct sighand_struct *newsighand; | |
1da177e4 | 879 | /* |
b2c903b8 ON |
880 | * This ->sighand is shared with the CLONE_SIGHAND |
881 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 882 | */ |
b2c903b8 ON |
883 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
884 | if (!newsighand) | |
885 | return -ENOMEM; | |
886 | ||
1da177e4 LT |
887 | atomic_set(&newsighand->count, 1); |
888 | memcpy(newsighand->action, oldsighand->action, | |
889 | sizeof(newsighand->action)); | |
890 | ||
891 | write_lock_irq(&tasklist_lock); | |
892 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 893 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
894 | spin_unlock(&oldsighand->siglock); |
895 | write_unlock_irq(&tasklist_lock); | |
896 | ||
fba2afaa | 897 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
898 | } |
899 | ||
aafe6c2a | 900 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
901 | return 0; |
902 | } | |
0840a90d | 903 | |
1da177e4 LT |
904 | /* |
905 | * These functions flushes out all traces of the currently running executable | |
906 | * so that a new one can be started | |
907 | */ | |
858119e1 | 908 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
909 | { |
910 | long j = -1; | |
badf1662 | 911 | struct fdtable *fdt; |
1da177e4 LT |
912 | |
913 | spin_lock(&files->file_lock); | |
914 | for (;;) { | |
915 | unsigned long set, i; | |
916 | ||
917 | j++; | |
918 | i = j * __NFDBITS; | |
badf1662 | 919 | fdt = files_fdtable(files); |
bbea9f69 | 920 | if (i >= fdt->max_fds) |
1da177e4 | 921 | break; |
badf1662 | 922 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
923 | if (!set) |
924 | continue; | |
badf1662 | 925 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
926 | spin_unlock(&files->file_lock); |
927 | for ( ; set ; i++,set >>= 1) { | |
928 | if (set & 1) { | |
929 | sys_close(i); | |
930 | } | |
931 | } | |
932 | spin_lock(&files->file_lock); | |
933 | ||
934 | } | |
935 | spin_unlock(&files->file_lock); | |
936 | } | |
937 | ||
59714d65 | 938 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
939 | { |
940 | /* buf must be at least sizeof(tsk->comm) in size */ | |
941 | task_lock(tsk); | |
942 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
943 | task_unlock(tsk); | |
59714d65 | 944 | return buf; |
1da177e4 LT |
945 | } |
946 | ||
947 | void set_task_comm(struct task_struct *tsk, char *buf) | |
948 | { | |
949 | task_lock(tsk); | |
950 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
951 | task_unlock(tsk); | |
952 | } | |
953 | ||
954 | int flush_old_exec(struct linux_binprm * bprm) | |
955 | { | |
956 | char * name; | |
957 | int i, ch, retval; | |
1da177e4 LT |
958 | char tcomm[sizeof(current->comm)]; |
959 | ||
960 | /* | |
961 | * Make sure we have a private signal table and that | |
962 | * we are unassociated from the previous thread group. | |
963 | */ | |
964 | retval = de_thread(current); | |
965 | if (retval) | |
966 | goto out; | |
967 | ||
925d1c40 MH |
968 | set_mm_exe_file(bprm->mm, bprm->file); |
969 | ||
1da177e4 LT |
970 | /* |
971 | * Release all of the old mmap stuff | |
972 | */ | |
973 | retval = exec_mmap(bprm->mm); | |
974 | if (retval) | |
fd8328be | 975 | goto out; |
1da177e4 LT |
976 | |
977 | bprm->mm = NULL; /* We're using it now */ | |
978 | ||
979 | /* This is the point of no return */ | |
1da177e4 LT |
980 | current->sas_ss_sp = current->sas_ss_size = 0; |
981 | ||
da9592ed | 982 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
6c5d5238 | 983 | set_dumpable(current->mm, 1); |
d6e71144 | 984 | else |
6c5d5238 | 985 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 986 | |
1da177e4 | 987 | name = bprm->filename; |
36772092 PBG |
988 | |
989 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
990 | for (i=0; (ch = *(name++)) != '\0';) { |
991 | if (ch == '/') | |
36772092 | 992 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
993 | else |
994 | if (i < (sizeof(tcomm) - 1)) | |
995 | tcomm[i++] = ch; | |
996 | } | |
997 | tcomm[i] = '\0'; | |
998 | set_task_comm(current, tcomm); | |
999 | ||
1000 | current->flags &= ~PF_RANDOMIZE; | |
1001 | flush_thread(); | |
1002 | ||
0551fbd2 BH |
1003 | /* Set the new mm task size. We have to do that late because it may |
1004 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1005 | * some architectures like powerpc | |
1006 | */ | |
1007 | current->mm->task_size = TASK_SIZE; | |
1008 | ||
a6f76f23 DH |
1009 | /* install the new credentials */ |
1010 | if (bprm->cred->uid != current_euid() || | |
1011 | bprm->cred->gid != current_egid()) { | |
d2d56c5f MH |
1012 | current->pdeath_signal = 0; |
1013 | } else if (file_permission(bprm->file, MAY_READ) || | |
a6f76f23 | 1014 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
6c5d5238 | 1015 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1016 | } |
1017 | ||
a6f76f23 DH |
1018 | current->personality &= ~bprm->per_clear; |
1019 | ||
1da177e4 LT |
1020 | /* An exec changes our domain. We are no longer part of the thread |
1021 | group */ | |
1022 | ||
1023 | current->self_exec_id++; | |
1024 | ||
1025 | flush_signal_handlers(current, 0); | |
1026 | flush_old_files(current->files); | |
1027 | ||
1028 | return 0; | |
1029 | ||
1da177e4 LT |
1030 | out: |
1031 | return retval; | |
1032 | } | |
1033 | ||
1034 | EXPORT_SYMBOL(flush_old_exec); | |
1035 | ||
a6f76f23 DH |
1036 | /* |
1037 | * install the new credentials for this executable | |
1038 | */ | |
1039 | void install_exec_creds(struct linux_binprm *bprm) | |
1040 | { | |
1041 | security_bprm_committing_creds(bprm); | |
1042 | ||
1043 | commit_creds(bprm->cred); | |
1044 | bprm->cred = NULL; | |
1045 | ||
1046 | /* cred_exec_mutex must be held at least to this point to prevent | |
1047 | * ptrace_attach() from altering our determination of the task's | |
1048 | * credentials; any time after this it may be unlocked */ | |
1049 | ||
1050 | security_bprm_committed_creds(bprm); | |
1051 | } | |
1052 | EXPORT_SYMBOL(install_exec_creds); | |
1053 | ||
1054 | /* | |
1055 | * determine how safe it is to execute the proposed program | |
1056 | * - the caller must hold current->cred_exec_mutex to protect against | |
1057 | * PTRACE_ATTACH | |
1058 | */ | |
0bf2f3ae | 1059 | void check_unsafe_exec(struct linux_binprm *bprm, struct files_struct *files) |
a6f76f23 | 1060 | { |
0bf2f3ae DH |
1061 | struct task_struct *p = current, *t; |
1062 | unsigned long flags; | |
1063 | unsigned n_fs, n_files, n_sighand; | |
a6f76f23 DH |
1064 | |
1065 | bprm->unsafe = tracehook_unsafe_exec(p); | |
1066 | ||
0bf2f3ae DH |
1067 | n_fs = 1; |
1068 | n_files = 1; | |
1069 | n_sighand = 1; | |
1070 | lock_task_sighand(p, &flags); | |
1071 | for (t = next_thread(p); t != p; t = next_thread(t)) { | |
1072 | if (t->fs == p->fs) | |
1073 | n_fs++; | |
1074 | if (t->files == files) | |
1075 | n_files++; | |
1076 | n_sighand++; | |
1077 | } | |
1078 | ||
1079 | if (atomic_read(&p->fs->count) > n_fs || | |
1080 | atomic_read(&p->files->count) > n_files || | |
1081 | atomic_read(&p->sighand->count) > n_sighand) | |
a6f76f23 | 1082 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
0bf2f3ae DH |
1083 | |
1084 | unlock_task_sighand(p, &flags); | |
a6f76f23 DH |
1085 | } |
1086 | ||
1da177e4 LT |
1087 | /* |
1088 | * Fill the binprm structure from the inode. | |
1089 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
a6f76f23 DH |
1090 | * |
1091 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1092 | */ |
1093 | int prepare_binprm(struct linux_binprm *bprm) | |
1094 | { | |
a6f76f23 | 1095 | umode_t mode; |
0f7fc9e4 | 1096 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1097 | int retval; |
1098 | ||
1099 | mode = inode->i_mode; | |
1da177e4 LT |
1100 | if (bprm->file->f_op == NULL) |
1101 | return -EACCES; | |
1102 | ||
a6f76f23 DH |
1103 | /* clear any previous set[ug]id data from a previous binary */ |
1104 | bprm->cred->euid = current_euid(); | |
1105 | bprm->cred->egid = current_egid(); | |
1da177e4 | 1106 | |
a6f76f23 | 1107 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1108 | /* Set-uid? */ |
1109 | if (mode & S_ISUID) { | |
a6f76f23 DH |
1110 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1111 | bprm->cred->euid = inode->i_uid; | |
1da177e4 LT |
1112 | } |
1113 | ||
1114 | /* Set-gid? */ | |
1115 | /* | |
1116 | * If setgid is set but no group execute bit then this | |
1117 | * is a candidate for mandatory locking, not a setgid | |
1118 | * executable. | |
1119 | */ | |
1120 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
a6f76f23 DH |
1121 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1122 | bprm->cred->egid = inode->i_gid; | |
1da177e4 LT |
1123 | } |
1124 | } | |
1125 | ||
1126 | /* fill in binprm security blob */ | |
a6f76f23 | 1127 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1128 | if (retval) |
1129 | return retval; | |
a6f76f23 | 1130 | bprm->cred_prepared = 1; |
1da177e4 | 1131 | |
a6f76f23 DH |
1132 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1133 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1134 | } |
1135 | ||
1136 | EXPORT_SYMBOL(prepare_binprm); | |
1137 | ||
4fc75ff4 NP |
1138 | /* |
1139 | * Arguments are '\0' separated strings found at the location bprm->p | |
1140 | * points to; chop off the first by relocating brpm->p to right after | |
1141 | * the first '\0' encountered. | |
1142 | */ | |
b6a2fea3 | 1143 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1144 | { |
b6a2fea3 OW |
1145 | int ret = 0; |
1146 | unsigned long offset; | |
1147 | char *kaddr; | |
1148 | struct page *page; | |
4fc75ff4 | 1149 | |
b6a2fea3 OW |
1150 | if (!bprm->argc) |
1151 | return 0; | |
1da177e4 | 1152 | |
b6a2fea3 OW |
1153 | do { |
1154 | offset = bprm->p & ~PAGE_MASK; | |
1155 | page = get_arg_page(bprm, bprm->p, 0); | |
1156 | if (!page) { | |
1157 | ret = -EFAULT; | |
1158 | goto out; | |
1159 | } | |
1160 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1161 | |
b6a2fea3 OW |
1162 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1163 | offset++, bprm->p++) | |
1164 | ; | |
4fc75ff4 | 1165 | |
b6a2fea3 OW |
1166 | kunmap_atomic(kaddr, KM_USER0); |
1167 | put_arg_page(page); | |
4fc75ff4 | 1168 | |
b6a2fea3 OW |
1169 | if (offset == PAGE_SIZE) |
1170 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1171 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1172 | |
b6a2fea3 OW |
1173 | bprm->p++; |
1174 | bprm->argc--; | |
1175 | ret = 0; | |
4fc75ff4 | 1176 | |
b6a2fea3 OW |
1177 | out: |
1178 | return ret; | |
1da177e4 | 1179 | } |
1da177e4 LT |
1180 | EXPORT_SYMBOL(remove_arg_zero); |
1181 | ||
1182 | /* | |
1183 | * cycle the list of binary formats handler, until one recognizes the image | |
1184 | */ | |
1185 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1186 | { | |
85f33466 | 1187 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1188 | int try,retval; |
1189 | struct linux_binfmt *fmt; | |
1da177e4 | 1190 | |
1da177e4 | 1191 | retval = security_bprm_check(bprm); |
6146f0d5 MZ |
1192 | if (retval) |
1193 | return retval; | |
1194 | retval = ima_bprm_check(bprm); | |
1da177e4 LT |
1195 | if (retval) |
1196 | return retval; | |
1197 | ||
1198 | /* kernel module loader fixup */ | |
1199 | /* so we don't try to load run modprobe in kernel space. */ | |
1200 | set_fs(USER_DS); | |
473ae30b AV |
1201 | |
1202 | retval = audit_bprm(bprm); | |
1203 | if (retval) | |
1204 | return retval; | |
1205 | ||
1da177e4 LT |
1206 | retval = -ENOENT; |
1207 | for (try=0; try<2; try++) { | |
1208 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1209 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1210 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1211 | if (!fn) | |
1212 | continue; | |
1213 | if (!try_module_get(fmt->module)) | |
1214 | continue; | |
1215 | read_unlock(&binfmt_lock); | |
1216 | retval = fn(bprm, regs); | |
85f33466 RM |
1217 | /* |
1218 | * Restore the depth counter to its starting value | |
1219 | * in this call, so we don't have to rely on every | |
1220 | * load_binary function to restore it on return. | |
1221 | */ | |
1222 | bprm->recursion_depth = depth; | |
1da177e4 | 1223 | if (retval >= 0) { |
85f33466 RM |
1224 | if (depth == 0) |
1225 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1226 | put_binfmt(fmt); |
1227 | allow_write_access(bprm->file); | |
1228 | if (bprm->file) | |
1229 | fput(bprm->file); | |
1230 | bprm->file = NULL; | |
1231 | current->did_exec = 1; | |
9f46080c | 1232 | proc_exec_connector(current); |
1da177e4 LT |
1233 | return retval; |
1234 | } | |
1235 | read_lock(&binfmt_lock); | |
1236 | put_binfmt(fmt); | |
1237 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1238 | break; | |
1239 | if (!bprm->file) { | |
1240 | read_unlock(&binfmt_lock); | |
1241 | return retval; | |
1242 | } | |
1243 | } | |
1244 | read_unlock(&binfmt_lock); | |
1245 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1246 | break; | |
5f4123be JB |
1247 | #ifdef CONFIG_MODULES |
1248 | } else { | |
1da177e4 LT |
1249 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1250 | if (printable(bprm->buf[0]) && | |
1251 | printable(bprm->buf[1]) && | |
1252 | printable(bprm->buf[2]) && | |
1253 | printable(bprm->buf[3])) | |
1254 | break; /* -ENOEXEC */ | |
1255 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1256 | #endif | |
1257 | } | |
1258 | } | |
1259 | return retval; | |
1260 | } | |
1261 | ||
1262 | EXPORT_SYMBOL(search_binary_handler); | |
1263 | ||
08a6fac1 AV |
1264 | void free_bprm(struct linux_binprm *bprm) |
1265 | { | |
1266 | free_arg_pages(bprm); | |
a6f76f23 DH |
1267 | if (bprm->cred) |
1268 | abort_creds(bprm->cred); | |
08a6fac1 AV |
1269 | kfree(bprm); |
1270 | } | |
1271 | ||
1da177e4 LT |
1272 | /* |
1273 | * sys_execve() executes a new program. | |
1274 | */ | |
1275 | int do_execve(char * filename, | |
1276 | char __user *__user *argv, | |
1277 | char __user *__user *envp, | |
1278 | struct pt_regs * regs) | |
1279 | { | |
1280 | struct linux_binprm *bprm; | |
1281 | struct file *file; | |
3b125388 | 1282 | struct files_struct *displaced; |
1da177e4 | 1283 | int retval; |
1da177e4 | 1284 | |
3b125388 | 1285 | retval = unshare_files(&displaced); |
fd8328be AV |
1286 | if (retval) |
1287 | goto out_ret; | |
1288 | ||
1da177e4 | 1289 | retval = -ENOMEM; |
11b0b5ab | 1290 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1291 | if (!bprm) |
fd8328be | 1292 | goto out_files; |
1da177e4 | 1293 | |
a6f76f23 DH |
1294 | retval = mutex_lock_interruptible(¤t->cred_exec_mutex); |
1295 | if (retval < 0) | |
1296 | goto out_free; | |
f9ce1f1c | 1297 | current->in_execve = 1; |
a6f76f23 DH |
1298 | |
1299 | retval = -ENOMEM; | |
1300 | bprm->cred = prepare_exec_creds(); | |
1301 | if (!bprm->cred) | |
1302 | goto out_unlock; | |
0bf2f3ae | 1303 | check_unsafe_exec(bprm, displaced); |
a6f76f23 | 1304 | |
1da177e4 LT |
1305 | file = open_exec(filename); |
1306 | retval = PTR_ERR(file); | |
1307 | if (IS_ERR(file)) | |
a6f76f23 | 1308 | goto out_unlock; |
1da177e4 LT |
1309 | |
1310 | sched_exec(); | |
1311 | ||
1da177e4 LT |
1312 | bprm->file = file; |
1313 | bprm->filename = filename; | |
1314 | bprm->interp = filename; | |
1da177e4 | 1315 | |
b6a2fea3 OW |
1316 | retval = bprm_mm_init(bprm); |
1317 | if (retval) | |
1318 | goto out_file; | |
1da177e4 | 1319 | |
b6a2fea3 | 1320 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1321 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1322 | goto out; |
1da177e4 | 1323 | |
b6a2fea3 | 1324 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1325 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1326 | goto out; |
1327 | ||
1328 | retval = prepare_binprm(bprm); | |
1329 | if (retval < 0) | |
1330 | goto out; | |
1331 | ||
1332 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1333 | if (retval < 0) | |
1334 | goto out; | |
1335 | ||
1336 | bprm->exec = bprm->p; | |
1337 | retval = copy_strings(bprm->envc, envp, bprm); | |
1338 | if (retval < 0) | |
1339 | goto out; | |
1340 | ||
1341 | retval = copy_strings(bprm->argc, argv, bprm); | |
1342 | if (retval < 0) | |
1343 | goto out; | |
1344 | ||
7b34e428 | 1345 | current->flags &= ~PF_KTHREAD; |
1da177e4 | 1346 | retval = search_binary_handler(bprm,regs); |
a6f76f23 DH |
1347 | if (retval < 0) |
1348 | goto out; | |
1da177e4 | 1349 | |
a6f76f23 | 1350 | /* execve succeeded */ |
f9ce1f1c | 1351 | current->in_execve = 0; |
a6f76f23 DH |
1352 | mutex_unlock(¤t->cred_exec_mutex); |
1353 | acct_update_integrals(current); | |
1354 | free_bprm(bprm); | |
1355 | if (displaced) | |
1356 | put_files_struct(displaced); | |
1357 | return retval; | |
1da177e4 | 1358 | |
a6f76f23 | 1359 | out: |
1da177e4 | 1360 | if (bprm->mm) |
b6a2fea3 | 1361 | mmput (bprm->mm); |
1da177e4 LT |
1362 | |
1363 | out_file: | |
1364 | if (bprm->file) { | |
1365 | allow_write_access(bprm->file); | |
1366 | fput(bprm->file); | |
1367 | } | |
a6f76f23 DH |
1368 | |
1369 | out_unlock: | |
f9ce1f1c | 1370 | current->in_execve = 0; |
a6f76f23 DH |
1371 | mutex_unlock(¤t->cred_exec_mutex); |
1372 | ||
1373 | out_free: | |
08a6fac1 | 1374 | free_bprm(bprm); |
1da177e4 | 1375 | |
fd8328be | 1376 | out_files: |
3b125388 AV |
1377 | if (displaced) |
1378 | reset_files_struct(displaced); | |
1da177e4 LT |
1379 | out_ret: |
1380 | return retval; | |
1381 | } | |
1382 | ||
1383 | int set_binfmt(struct linux_binfmt *new) | |
1384 | { | |
1385 | struct linux_binfmt *old = current->binfmt; | |
1386 | ||
1387 | if (new) { | |
1388 | if (!try_module_get(new->module)) | |
1389 | return -1; | |
1390 | } | |
1391 | current->binfmt = new; | |
1392 | if (old) | |
1393 | module_put(old->module); | |
1394 | return 0; | |
1395 | } | |
1396 | ||
1397 | EXPORT_SYMBOL(set_binfmt); | |
1398 | ||
1da177e4 LT |
1399 | /* format_corename will inspect the pattern parameter, and output a |
1400 | * name into corename, which must have space for at least | |
1401 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1402 | */ | |
6409324b | 1403 | static int format_corename(char *corename, long signr) |
1da177e4 | 1404 | { |
86a264ab | 1405 | const struct cred *cred = current_cred(); |
565b9b14 ON |
1406 | const char *pat_ptr = core_pattern; |
1407 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 LT |
1408 | char *out_ptr = corename; |
1409 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1410 | int rc; | |
1411 | int pid_in_pattern = 0; | |
1412 | ||
1413 | /* Repeat as long as we have more pattern to process and more output | |
1414 | space */ | |
1415 | while (*pat_ptr) { | |
1416 | if (*pat_ptr != '%') { | |
1417 | if (out_ptr == out_end) | |
1418 | goto out; | |
1419 | *out_ptr++ = *pat_ptr++; | |
1420 | } else { | |
1421 | switch (*++pat_ptr) { | |
1422 | case 0: | |
1423 | goto out; | |
1424 | /* Double percent, output one percent */ | |
1425 | case '%': | |
1426 | if (out_ptr == out_end) | |
1427 | goto out; | |
1428 | *out_ptr++ = '%'; | |
1429 | break; | |
1430 | /* pid */ | |
1431 | case 'p': | |
1432 | pid_in_pattern = 1; | |
1433 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1434 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1435 | if (rc > out_end - out_ptr) |
1436 | goto out; | |
1437 | out_ptr += rc; | |
1438 | break; | |
1439 | /* uid */ | |
1440 | case 'u': | |
1441 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1442 | "%d", cred->uid); |
1da177e4 LT |
1443 | if (rc > out_end - out_ptr) |
1444 | goto out; | |
1445 | out_ptr += rc; | |
1446 | break; | |
1447 | /* gid */ | |
1448 | case 'g': | |
1449 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1450 | "%d", cred->gid); |
1da177e4 LT |
1451 | if (rc > out_end - out_ptr) |
1452 | goto out; | |
1453 | out_ptr += rc; | |
1454 | break; | |
1455 | /* signal that caused the coredump */ | |
1456 | case 's': | |
1457 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1458 | "%ld", signr); | |
1459 | if (rc > out_end - out_ptr) | |
1460 | goto out; | |
1461 | out_ptr += rc; | |
1462 | break; | |
1463 | /* UNIX time of coredump */ | |
1464 | case 't': { | |
1465 | struct timeval tv; | |
1466 | do_gettimeofday(&tv); | |
1467 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1468 | "%lu", tv.tv_sec); | |
1469 | if (rc > out_end - out_ptr) | |
1470 | goto out; | |
1471 | out_ptr += rc; | |
1472 | break; | |
1473 | } | |
1474 | /* hostname */ | |
1475 | case 'h': | |
1476 | down_read(&uts_sem); | |
1477 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1478 | "%s", utsname()->nodename); |
1da177e4 LT |
1479 | up_read(&uts_sem); |
1480 | if (rc > out_end - out_ptr) | |
1481 | goto out; | |
1482 | out_ptr += rc; | |
1483 | break; | |
1484 | /* executable */ | |
1485 | case 'e': | |
1486 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1487 | "%s", current->comm); | |
1488 | if (rc > out_end - out_ptr) | |
1489 | goto out; | |
1490 | out_ptr += rc; | |
1491 | break; | |
74aadce9 NH |
1492 | /* core limit size */ |
1493 | case 'c': | |
1494 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1495 | "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); | |
1496 | if (rc > out_end - out_ptr) | |
1497 | goto out; | |
1498 | out_ptr += rc; | |
1499 | break; | |
1da177e4 LT |
1500 | default: |
1501 | break; | |
1502 | } | |
1503 | ++pat_ptr; | |
1504 | } | |
1505 | } | |
1506 | /* Backward compatibility with core_uses_pid: | |
1507 | * | |
1508 | * If core_pattern does not include a %p (as is the default) | |
1509 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1510 | * the filename. Do not do this for piped commands. */ |
6409324b | 1511 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1da177e4 | 1512 | rc = snprintf(out_ptr, out_end - out_ptr, |
b488893a | 1513 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1514 | if (rc > out_end - out_ptr) |
1515 | goto out; | |
1516 | out_ptr += rc; | |
1517 | } | |
c4bbafda | 1518 | out: |
1da177e4 | 1519 | *out_ptr = 0; |
c4bbafda | 1520 | return ispipe; |
1da177e4 LT |
1521 | } |
1522 | ||
8cd9c249 | 1523 | static int zap_process(struct task_struct *start) |
aceecc04 ON |
1524 | { |
1525 | struct task_struct *t; | |
8cd9c249 | 1526 | int nr = 0; |
281de339 | 1527 | |
d5f70c00 ON |
1528 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1529 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1530 | |
1531 | t = start; | |
1532 | do { | |
1533 | if (t != current && t->mm) { | |
281de339 ON |
1534 | sigaddset(&t->pending.signal, SIGKILL); |
1535 | signal_wake_up(t, 1); | |
8cd9c249 | 1536 | nr++; |
aceecc04 | 1537 | } |
e4901f92 | 1538 | } while_each_thread(start, t); |
8cd9c249 ON |
1539 | |
1540 | return nr; | |
aceecc04 ON |
1541 | } |
1542 | ||
dcf560c5 | 1543 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1544 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1545 | { |
1546 | struct task_struct *g, *p; | |
5debfa6d | 1547 | unsigned long flags; |
8cd9c249 | 1548 | int nr = -EAGAIN; |
dcf560c5 ON |
1549 | |
1550 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1551 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1552 | mm->core_state = core_state; |
dcf560c5 | 1553 | tsk->signal->group_exit_code = exit_code; |
8cd9c249 | 1554 | nr = zap_process(tsk); |
1da177e4 | 1555 | } |
dcf560c5 | 1556 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1557 | if (unlikely(nr < 0)) |
1558 | return nr; | |
1da177e4 | 1559 | |
8cd9c249 | 1560 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1561 | goto done; |
e4901f92 ON |
1562 | /* |
1563 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1564 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1565 | * lock, but this is safe wrt: |
1566 | * | |
1567 | * fork: | |
1568 | * None of sub-threads can fork after zap_process(leader). All | |
1569 | * processes which were created before this point should be | |
1570 | * visible to zap_threads() because copy_process() adds the new | |
1571 | * process to the tail of init_task.tasks list, and lock/unlock | |
1572 | * of ->siglock provides a memory barrier. | |
1573 | * | |
1574 | * do_exit: | |
1575 | * The caller holds mm->mmap_sem. This means that the task which | |
1576 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1577 | * its ->mm. | |
1578 | * | |
1579 | * de_thread: | |
1580 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1581 | * we must see either old or new leader, this does not matter. | |
1582 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1583 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1584 | * it can't fail. | |
1585 | * | |
1586 | * Note also that "g" can be the old leader with ->mm == NULL | |
1587 | * and already unhashed and thus removed from ->thread_group. | |
1588 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1589 | * clear the ->next pointer, we will find the new leader via | |
1590 | * next_thread(). | |
1591 | */ | |
7b1c6154 | 1592 | rcu_read_lock(); |
aceecc04 | 1593 | for_each_process(g) { |
5debfa6d ON |
1594 | if (g == tsk->group_leader) |
1595 | continue; | |
15b9f360 ON |
1596 | if (g->flags & PF_KTHREAD) |
1597 | continue; | |
aceecc04 ON |
1598 | p = g; |
1599 | do { | |
1600 | if (p->mm) { | |
15b9f360 | 1601 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1602 | lock_task_sighand(p, &flags); |
8cd9c249 | 1603 | nr += zap_process(p); |
5debfa6d ON |
1604 | unlock_task_sighand(p, &flags); |
1605 | } | |
aceecc04 ON |
1606 | break; |
1607 | } | |
e4901f92 | 1608 | } while_each_thread(g, p); |
aceecc04 | 1609 | } |
7b1c6154 | 1610 | rcu_read_unlock(); |
5debfa6d | 1611 | done: |
c5f1cc8c | 1612 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1613 | return nr; |
1da177e4 LT |
1614 | } |
1615 | ||
9d5b327b | 1616 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1617 | { |
dcf560c5 ON |
1618 | struct task_struct *tsk = current; |
1619 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1620 | struct completion *vfork_done; |
2384f55f | 1621 | int core_waiters; |
1da177e4 | 1622 | |
9d5b327b | 1623 | init_completion(&core_state->startup); |
b564daf8 ON |
1624 | core_state->dumper.task = tsk; |
1625 | core_state->dumper.next = NULL; | |
9d5b327b | 1626 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
2384f55f ON |
1627 | up_write(&mm->mmap_sem); |
1628 | ||
dcf560c5 ON |
1629 | if (unlikely(core_waiters < 0)) |
1630 | goto fail; | |
1631 | ||
1632 | /* | |
1633 | * Make sure nobody is waiting for us to release the VM, | |
1634 | * otherwise we can deadlock when we wait on each other | |
1635 | */ | |
1636 | vfork_done = tsk->vfork_done; | |
1637 | if (vfork_done) { | |
1638 | tsk->vfork_done = NULL; | |
1639 | complete(vfork_done); | |
1640 | } | |
1641 | ||
2384f55f | 1642 | if (core_waiters) |
9d5b327b | 1643 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1644 | fail: |
dcf560c5 | 1645 | return core_waiters; |
1da177e4 LT |
1646 | } |
1647 | ||
a94e2d40 ON |
1648 | static void coredump_finish(struct mm_struct *mm) |
1649 | { | |
1650 | struct core_thread *curr, *next; | |
1651 | struct task_struct *task; | |
1652 | ||
1653 | next = mm->core_state->dumper.next; | |
1654 | while ((curr = next) != NULL) { | |
1655 | next = curr->next; | |
1656 | task = curr->task; | |
1657 | /* | |
1658 | * see exit_mm(), curr->task must not see | |
1659 | * ->task == NULL before we read ->next. | |
1660 | */ | |
1661 | smp_mb(); | |
1662 | curr->task = NULL; | |
1663 | wake_up_process(task); | |
1664 | } | |
1665 | ||
1666 | mm->core_state = NULL; | |
1667 | } | |
1668 | ||
6c5d5238 KH |
1669 | /* |
1670 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1671 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1672 | * these bits are not changed atomically. So get_dumpable can observe the | |
1673 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1674 | * return either old dumpable or new one by paying attention to the order of | |
1675 | * modifying the bits. | |
1676 | * | |
1677 | * dumpable | mm->flags (binary) | |
1678 | * old new | initial interim final | |
1679 | * ---------+----------------------- | |
1680 | * 0 1 | 00 01 01 | |
1681 | * 0 2 | 00 10(*) 11 | |
1682 | * 1 0 | 01 00 00 | |
1683 | * 1 2 | 01 11 11 | |
1684 | * 2 0 | 11 10(*) 00 | |
1685 | * 2 1 | 11 11 01 | |
1686 | * | |
1687 | * (*) get_dumpable regards interim value of 10 as 11. | |
1688 | */ | |
1689 | void set_dumpable(struct mm_struct *mm, int value) | |
1690 | { | |
1691 | switch (value) { | |
1692 | case 0: | |
1693 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1694 | smp_wmb(); | |
1695 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1696 | break; | |
1697 | case 1: | |
1698 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1699 | smp_wmb(); | |
1700 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1701 | break; | |
1702 | case 2: | |
1703 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1704 | smp_wmb(); | |
1705 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1706 | break; | |
1707 | } | |
1708 | } | |
6c5d5238 KH |
1709 | |
1710 | int get_dumpable(struct mm_struct *mm) | |
1711 | { | |
1712 | int ret; | |
1713 | ||
1714 | ret = mm->flags & 0x3; | |
1715 | return (ret >= 2) ? 2 : ret; | |
1716 | } | |
1717 | ||
8cd3ac3a | 1718 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1da177e4 | 1719 | { |
9d5b327b | 1720 | struct core_state core_state; |
1da177e4 LT |
1721 | char corename[CORENAME_MAX_SIZE + 1]; |
1722 | struct mm_struct *mm = current->mm; | |
1723 | struct linux_binfmt * binfmt; | |
1724 | struct inode * inode; | |
1725 | struct file * file; | |
d84f4f99 DH |
1726 | const struct cred *old_cred; |
1727 | struct cred *cred; | |
1da177e4 | 1728 | int retval = 0; |
d6e71144 | 1729 | int flag = 0; |
d025c9db | 1730 | int ispipe = 0; |
7dc0b22e | 1731 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
74aadce9 NH |
1732 | char **helper_argv = NULL; |
1733 | int helper_argc = 0; | |
1734 | char *delimit; | |
1da177e4 | 1735 | |
0a4ff8c2 SG |
1736 | audit_core_dumps(signr); |
1737 | ||
1da177e4 LT |
1738 | binfmt = current->binfmt; |
1739 | if (!binfmt || !binfmt->core_dump) | |
1740 | goto fail; | |
d84f4f99 DH |
1741 | |
1742 | cred = prepare_creds(); | |
1743 | if (!cred) { | |
1744 | retval = -ENOMEM; | |
1745 | goto fail; | |
1746 | } | |
1747 | ||
1da177e4 | 1748 | down_write(&mm->mmap_sem); |
00ec99da RM |
1749 | /* |
1750 | * If another thread got here first, or we are not dumpable, bail out. | |
1751 | */ | |
999d9fc1 | 1752 | if (mm->core_state || !get_dumpable(mm)) { |
1da177e4 | 1753 | up_write(&mm->mmap_sem); |
d84f4f99 | 1754 | put_cred(cred); |
1da177e4 LT |
1755 | goto fail; |
1756 | } | |
d6e71144 AC |
1757 | |
1758 | /* | |
1759 | * We cannot trust fsuid as being the "true" uid of the | |
1760 | * process nor do we know its entire history. We only know it | |
1761 | * was tainted so we dump it as root in mode 2. | |
1762 | */ | |
6c5d5238 | 1763 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 | 1764 | flag = O_EXCL; /* Stop rewrite attacks */ |
d84f4f99 | 1765 | cred->fsuid = 0; /* Dump root private */ |
d6e71144 | 1766 | } |
1291cf41 | 1767 | |
9d5b327b | 1768 | retval = coredump_wait(exit_code, &core_state); |
d84f4f99 DH |
1769 | if (retval < 0) { |
1770 | put_cred(cred); | |
1291cf41 | 1771 | goto fail; |
d84f4f99 DH |
1772 | } |
1773 | ||
1774 | old_cred = override_creds(cred); | |
1da177e4 LT |
1775 | |
1776 | /* | |
1777 | * Clear any false indication of pending signals that might | |
1778 | * be seen by the filesystem code called to write the core file. | |
1779 | */ | |
1da177e4 LT |
1780 | clear_thread_flag(TIF_SIGPENDING); |
1781 | ||
1da177e4 LT |
1782 | /* |
1783 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1784 | * uses lock_kernel() | |
1785 | */ | |
1786 | lock_kernel(); | |
6409324b | 1787 | ispipe = format_corename(corename, signr); |
1da177e4 | 1788 | unlock_kernel(); |
7dc0b22e NH |
1789 | /* |
1790 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1791 | * to a pipe. Since we're not writing directly to the filesystem | |
1792 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1793 | * created unless the pipe reader choses to write out the core file | |
1794 | * at which point file size limits and permissions will be imposed | |
1795 | * as it does with any other process | |
1796 | */ | |
74aadce9 | 1797 | if ((!ispipe) && (core_limit < binfmt->min_coredump)) |
7dc0b22e NH |
1798 | goto fail_unlock; |
1799 | ||
c4bbafda | 1800 | if (ispipe) { |
74aadce9 | 1801 | helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc); |
350eaf79 TH |
1802 | if (!helper_argv) { |
1803 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
1804 | __func__); | |
1805 | goto fail_unlock; | |
1806 | } | |
74aadce9 NH |
1807 | /* Terminate the string before the first option */ |
1808 | delimit = strchr(corename, ' '); | |
1809 | if (delimit) | |
1810 | *delimit = '\0'; | |
32321137 NH |
1811 | delimit = strrchr(helper_argv[0], '/'); |
1812 | if (delimit) | |
1813 | delimit++; | |
1814 | else | |
1815 | delimit = helper_argv[0]; | |
1816 | if (!strcmp(delimit, current->comm)) { | |
1817 | printk(KERN_NOTICE "Recursive core dump detected, " | |
1818 | "aborting\n"); | |
1819 | goto fail_unlock; | |
1820 | } | |
1821 | ||
1822 | core_limit = RLIM_INFINITY; | |
1823 | ||
d025c9db | 1824 | /* SIGPIPE can happen, but it's just never processed */ |
32321137 NH |
1825 | if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, |
1826 | &file)) { | |
d025c9db AK |
1827 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1828 | corename); | |
1829 | goto fail_unlock; | |
1830 | } | |
d025c9db AK |
1831 | } else |
1832 | file = filp_open(corename, | |
6d4df677 AD |
1833 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1834 | 0600); | |
1da177e4 LT |
1835 | if (IS_ERR(file)) |
1836 | goto fail_unlock; | |
0f7fc9e4 | 1837 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1838 | if (inode->i_nlink > 1) |
1839 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1840 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1841 | goto close_fail; |
1842 | ||
d025c9db AK |
1843 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1844 | but keep the previous behaviour for now. */ | |
1845 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 | 1846 | goto close_fail; |
c46f739d IM |
1847 | /* |
1848 | * Dont allow local users get cute and trick others to coredump | |
1849 | * into their pre-created files: | |
1850 | */ | |
da9592ed | 1851 | if (inode->i_uid != current_fsuid()) |
c46f739d | 1852 | goto close_fail; |
1da177e4 LT |
1853 | if (!file->f_op) |
1854 | goto close_fail; | |
1855 | if (!file->f_op->write) | |
1856 | goto close_fail; | |
0f7fc9e4 | 1857 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1858 | goto close_fail; |
1859 | ||
7dc0b22e | 1860 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1861 | |
1862 | if (retval) | |
1863 | current->signal->group_exit_code |= 0x80; | |
1864 | close_fail: | |
1865 | filp_close(file, NULL); | |
1866 | fail_unlock: | |
74aadce9 NH |
1867 | if (helper_argv) |
1868 | argv_free(helper_argv); | |
1869 | ||
d84f4f99 DH |
1870 | revert_creds(old_cred); |
1871 | put_cred(cred); | |
a94e2d40 | 1872 | coredump_finish(mm); |
1da177e4 | 1873 | fail: |
8cd3ac3a | 1874 | return; |
1da177e4 | 1875 | } |