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> | |
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> |
5ad4e53b | 56 | #include <linux/fs_struct.h> |
1da177e4 LT |
57 | |
58 | #include <asm/uaccess.h> | |
59 | #include <asm/mmu_context.h> | |
b6a2fea3 | 60 | #include <asm/tlb.h> |
a6f76f23 | 61 | #include "internal.h" |
1da177e4 | 62 | |
1da177e4 | 63 | int core_uses_pid; |
71ce92f3 | 64 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
d6e71144 AC |
65 | int suid_dumpable = 0; |
66 | ||
1da177e4 LT |
67 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
68 | ||
e4dc1b14 | 69 | static LIST_HEAD(formats); |
1da177e4 LT |
70 | static DEFINE_RWLOCK(binfmt_lock); |
71 | ||
74641f58 | 72 | int __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 73 | { |
1da177e4 LT |
74 | if (!fmt) |
75 | return -EINVAL; | |
1da177e4 | 76 | write_lock(&binfmt_lock); |
74641f58 IK |
77 | insert ? list_add(&fmt->lh, &formats) : |
78 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 LT |
79 | write_unlock(&binfmt_lock); |
80 | return 0; | |
81 | } | |
82 | ||
74641f58 | 83 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 84 | |
f6b450d4 | 85 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 86 | { |
1da177e4 | 87 | write_lock(&binfmt_lock); |
e4dc1b14 | 88 | list_del(&fmt->lh); |
1da177e4 | 89 | write_unlock(&binfmt_lock); |
1da177e4 LT |
90 | } |
91 | ||
92 | EXPORT_SYMBOL(unregister_binfmt); | |
93 | ||
94 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
95 | { | |
96 | module_put(fmt->module); | |
97 | } | |
98 | ||
99 | /* | |
100 | * Note that a shared library must be both readable and executable due to | |
101 | * security reasons. | |
102 | * | |
103 | * Also note that we take the address to load from from the file itself. | |
104 | */ | |
1e7bfb21 | 105 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 106 | { |
964bd183 | 107 | struct file *file; |
964bd183 AV |
108 | char *tmp = getname(library); |
109 | int error = PTR_ERR(tmp); | |
110 | ||
6e8341a1 AV |
111 | if (IS_ERR(tmp)) |
112 | goto out; | |
113 | ||
114 | file = do_filp_open(AT_FDCWD, tmp, | |
115 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
116 | MAY_READ | MAY_EXEC | MAY_OPEN); | |
117 | putname(tmp); | |
118 | error = PTR_ERR(file); | |
119 | if (IS_ERR(file)) | |
1da177e4 LT |
120 | goto out; |
121 | ||
122 | error = -EINVAL; | |
6e8341a1 | 123 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
1da177e4 LT |
124 | goto exit; |
125 | ||
30524472 | 126 | error = -EACCES; |
6e8341a1 | 127 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
1da177e4 LT |
128 | goto exit; |
129 | ||
6110e3ab EP |
130 | fsnotify_open(file->f_path.dentry); |
131 | ||
1da177e4 LT |
132 | error = -ENOEXEC; |
133 | if(file->f_op) { | |
134 | struct linux_binfmt * fmt; | |
135 | ||
136 | read_lock(&binfmt_lock); | |
e4dc1b14 | 137 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
138 | if (!fmt->load_shlib) |
139 | continue; | |
140 | if (!try_module_get(fmt->module)) | |
141 | continue; | |
142 | read_unlock(&binfmt_lock); | |
143 | error = fmt->load_shlib(file); | |
144 | read_lock(&binfmt_lock); | |
145 | put_binfmt(fmt); | |
146 | if (error != -ENOEXEC) | |
147 | break; | |
148 | } | |
149 | read_unlock(&binfmt_lock); | |
150 | } | |
6e8341a1 | 151 | exit: |
1da177e4 LT |
152 | fput(file); |
153 | out: | |
154 | return error; | |
1da177e4 LT |
155 | } |
156 | ||
b6a2fea3 OW |
157 | #ifdef CONFIG_MMU |
158 | ||
159 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
160 | int write) | |
161 | { | |
162 | struct page *page; | |
163 | int ret; | |
164 | ||
165 | #ifdef CONFIG_STACK_GROWSUP | |
166 | if (write) { | |
167 | ret = expand_stack_downwards(bprm->vma, pos); | |
168 | if (ret < 0) | |
169 | return NULL; | |
170 | } | |
171 | #endif | |
172 | ret = get_user_pages(current, bprm->mm, pos, | |
173 | 1, write, 1, &page, NULL); | |
174 | if (ret <= 0) | |
175 | return NULL; | |
176 | ||
177 | if (write) { | |
b6a2fea3 | 178 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
179 | struct rlimit *rlim; |
180 | ||
181 | /* | |
182 | * We've historically supported up to 32 pages (ARG_MAX) | |
183 | * of argument strings even with small stacks | |
184 | */ | |
185 | if (size <= ARG_MAX) | |
186 | return page; | |
b6a2fea3 OW |
187 | |
188 | /* | |
189 | * Limit to 1/4-th the stack size for the argv+env strings. | |
190 | * This ensures that: | |
191 | * - the remaining binfmt code will not run out of stack space, | |
192 | * - the program will have a reasonable amount of stack left | |
193 | * to work from. | |
194 | */ | |
a64e715f | 195 | rlim = current->signal->rlim; |
b6a2fea3 OW |
196 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { |
197 | put_page(page); | |
198 | return NULL; | |
199 | } | |
200 | } | |
201 | ||
202 | return page; | |
203 | } | |
204 | ||
205 | static void put_arg_page(struct page *page) | |
206 | { | |
207 | put_page(page); | |
208 | } | |
209 | ||
210 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
211 | { | |
212 | } | |
213 | ||
214 | static void free_arg_pages(struct linux_binprm *bprm) | |
215 | { | |
216 | } | |
217 | ||
218 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
219 | struct page *page) | |
220 | { | |
221 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
222 | } | |
223 | ||
224 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
225 | { | |
eaccbfa5 | 226 | int err; |
b6a2fea3 OW |
227 | struct vm_area_struct *vma = NULL; |
228 | struct mm_struct *mm = bprm->mm; | |
229 | ||
230 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
231 | if (!vma) | |
eaccbfa5 | 232 | return -ENOMEM; |
b6a2fea3 OW |
233 | |
234 | down_write(&mm->mmap_sem); | |
235 | vma->vm_mm = mm; | |
236 | ||
237 | /* | |
238 | * Place the stack at the largest stack address the architecture | |
239 | * supports. Later, we'll move this to an appropriate place. We don't | |
240 | * use STACK_TOP because that can depend on attributes which aren't | |
241 | * configured yet. | |
242 | */ | |
243 | vma->vm_end = STACK_TOP_MAX; | |
244 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
b6a2fea3 | 245 | vma->vm_flags = VM_STACK_FLAGS; |
3ed75eb8 | 246 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
b6a2fea3 | 247 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 248 | if (err) |
b6a2fea3 | 249 | goto err; |
b6a2fea3 OW |
250 | |
251 | mm->stack_vm = mm->total_vm = 1; | |
252 | up_write(&mm->mmap_sem); | |
b6a2fea3 | 253 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 254 | return 0; |
b6a2fea3 | 255 | err: |
eaccbfa5 LFC |
256 | up_write(&mm->mmap_sem); |
257 | bprm->vma = NULL; | |
258 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
259 | return err; |
260 | } | |
261 | ||
262 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
263 | { | |
264 | return len <= MAX_ARG_STRLEN; | |
265 | } | |
266 | ||
267 | #else | |
268 | ||
269 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
270 | int write) | |
271 | { | |
272 | struct page *page; | |
273 | ||
274 | page = bprm->page[pos / PAGE_SIZE]; | |
275 | if (!page && write) { | |
276 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
277 | if (!page) | |
278 | return NULL; | |
279 | bprm->page[pos / PAGE_SIZE] = page; | |
280 | } | |
281 | ||
282 | return page; | |
283 | } | |
284 | ||
285 | static void put_arg_page(struct page *page) | |
286 | { | |
287 | } | |
288 | ||
289 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
290 | { | |
291 | if (bprm->page[i]) { | |
292 | __free_page(bprm->page[i]); | |
293 | bprm->page[i] = NULL; | |
294 | } | |
295 | } | |
296 | ||
297 | static void free_arg_pages(struct linux_binprm *bprm) | |
298 | { | |
299 | int i; | |
300 | ||
301 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
302 | free_arg_page(bprm, i); | |
303 | } | |
304 | ||
305 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
306 | struct page *page) | |
307 | { | |
308 | } | |
309 | ||
310 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
311 | { | |
312 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
313 | return 0; | |
314 | } | |
315 | ||
316 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
317 | { | |
318 | return len <= bprm->p; | |
319 | } | |
320 | ||
321 | #endif /* CONFIG_MMU */ | |
322 | ||
323 | /* | |
324 | * Create a new mm_struct and populate it with a temporary stack | |
325 | * vm_area_struct. We don't have enough context at this point to set the stack | |
326 | * flags, permissions, and offset, so we use temporary values. We'll update | |
327 | * them later in setup_arg_pages(). | |
328 | */ | |
329 | int bprm_mm_init(struct linux_binprm *bprm) | |
330 | { | |
331 | int err; | |
332 | struct mm_struct *mm = NULL; | |
333 | ||
334 | bprm->mm = mm = mm_alloc(); | |
335 | err = -ENOMEM; | |
336 | if (!mm) | |
337 | goto err; | |
338 | ||
339 | err = init_new_context(current, mm); | |
340 | if (err) | |
341 | goto err; | |
342 | ||
343 | err = __bprm_mm_init(bprm); | |
344 | if (err) | |
345 | goto err; | |
346 | ||
347 | return 0; | |
348 | ||
349 | err: | |
350 | if (mm) { | |
351 | bprm->mm = NULL; | |
352 | mmdrop(mm); | |
353 | } | |
354 | ||
355 | return err; | |
356 | } | |
357 | ||
1da177e4 LT |
358 | /* |
359 | * count() counts the number of strings in array ARGV. | |
360 | */ | |
361 | static int count(char __user * __user * argv, int max) | |
362 | { | |
363 | int i = 0; | |
364 | ||
365 | if (argv != NULL) { | |
366 | for (;;) { | |
367 | char __user * p; | |
368 | ||
369 | if (get_user(p, argv)) | |
370 | return -EFAULT; | |
371 | if (!p) | |
372 | break; | |
373 | argv++; | |
362e6663 | 374 | if (i++ >= max) |
1da177e4 LT |
375 | return -E2BIG; |
376 | cond_resched(); | |
377 | } | |
378 | } | |
379 | return i; | |
380 | } | |
381 | ||
382 | /* | |
b6a2fea3 OW |
383 | * 'copy_strings()' copies argument/environment strings from the old |
384 | * processes's memory to the new process's stack. The call to get_user_pages() | |
385 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 386 | */ |
75c96f85 AB |
387 | static int copy_strings(int argc, char __user * __user * argv, |
388 | struct linux_binprm *bprm) | |
1da177e4 LT |
389 | { |
390 | struct page *kmapped_page = NULL; | |
391 | char *kaddr = NULL; | |
b6a2fea3 | 392 | unsigned long kpos = 0; |
1da177e4 LT |
393 | int ret; |
394 | ||
395 | while (argc-- > 0) { | |
396 | char __user *str; | |
397 | int len; | |
398 | unsigned long pos; | |
399 | ||
400 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 401 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
402 | ret = -EFAULT; |
403 | goto out; | |
404 | } | |
405 | ||
b6a2fea3 | 406 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
407 | ret = -E2BIG; |
408 | goto out; | |
409 | } | |
410 | ||
b6a2fea3 | 411 | /* We're going to work our way backwords. */ |
1da177e4 | 412 | pos = bprm->p; |
b6a2fea3 OW |
413 | str += len; |
414 | bprm->p -= len; | |
1da177e4 LT |
415 | |
416 | while (len > 0) { | |
1da177e4 | 417 | int offset, bytes_to_copy; |
1da177e4 LT |
418 | |
419 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
420 | if (offset == 0) |
421 | offset = PAGE_SIZE; | |
422 | ||
423 | bytes_to_copy = offset; | |
424 | if (bytes_to_copy > len) | |
425 | bytes_to_copy = len; | |
426 | ||
427 | offset -= bytes_to_copy; | |
428 | pos -= bytes_to_copy; | |
429 | str -= bytes_to_copy; | |
430 | len -= bytes_to_copy; | |
431 | ||
432 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
433 | struct page *page; | |
434 | ||
435 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 436 | if (!page) { |
b6a2fea3 | 437 | ret = -E2BIG; |
1da177e4 LT |
438 | goto out; |
439 | } | |
1da177e4 | 440 | |
b6a2fea3 OW |
441 | if (kmapped_page) { |
442 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 443 | kunmap(kmapped_page); |
b6a2fea3 OW |
444 | put_arg_page(kmapped_page); |
445 | } | |
1da177e4 LT |
446 | kmapped_page = page; |
447 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
448 | kpos = pos & PAGE_MASK; |
449 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 450 | } |
b6a2fea3 | 451 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
452 | ret = -EFAULT; |
453 | goto out; | |
454 | } | |
1da177e4 LT |
455 | } |
456 | } | |
457 | ret = 0; | |
458 | out: | |
b6a2fea3 OW |
459 | if (kmapped_page) { |
460 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 461 | kunmap(kmapped_page); |
b6a2fea3 OW |
462 | put_arg_page(kmapped_page); |
463 | } | |
1da177e4 LT |
464 | return ret; |
465 | } | |
466 | ||
467 | /* | |
468 | * Like copy_strings, but get argv and its values from kernel memory. | |
469 | */ | |
470 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
471 | { | |
472 | int r; | |
473 | mm_segment_t oldfs = get_fs(); | |
474 | set_fs(KERNEL_DS); | |
475 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
476 | set_fs(oldfs); | |
477 | return r; | |
478 | } | |
1da177e4 LT |
479 | EXPORT_SYMBOL(copy_strings_kernel); |
480 | ||
481 | #ifdef CONFIG_MMU | |
b6a2fea3 | 482 | |
1da177e4 | 483 | /* |
b6a2fea3 OW |
484 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
485 | * the binfmt code determines where the new stack should reside, we shift it to | |
486 | * its final location. The process proceeds as follows: | |
1da177e4 | 487 | * |
b6a2fea3 OW |
488 | * 1) Use shift to calculate the new vma endpoints. |
489 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
490 | * arguments passed to subsequent functions are consistent. | |
491 | * 3) Move vma's page tables to the new range. | |
492 | * 4) Free up any cleared pgd range. | |
493 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 494 | */ |
b6a2fea3 | 495 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
496 | { |
497 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
498 | unsigned long old_start = vma->vm_start; |
499 | unsigned long old_end = vma->vm_end; | |
500 | unsigned long length = old_end - old_start; | |
501 | unsigned long new_start = old_start - shift; | |
502 | unsigned long new_end = old_end - shift; | |
503 | struct mmu_gather *tlb; | |
1da177e4 | 504 | |
b6a2fea3 | 505 | BUG_ON(new_start > new_end); |
1da177e4 | 506 | |
b6a2fea3 OW |
507 | /* |
508 | * ensure there are no vmas between where we want to go | |
509 | * and where we are | |
510 | */ | |
511 | if (vma != find_vma(mm, new_start)) | |
512 | return -EFAULT; | |
513 | ||
514 | /* | |
515 | * cover the whole range: [new_start, old_end) | |
516 | */ | |
517 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
518 | ||
519 | /* | |
520 | * move the page tables downwards, on failure we rely on | |
521 | * process cleanup to remove whatever mess we made. | |
522 | */ | |
523 | if (length != move_page_tables(vma, old_start, | |
524 | vma, new_start, length)) | |
525 | return -ENOMEM; | |
526 | ||
527 | lru_add_drain(); | |
528 | tlb = tlb_gather_mmu(mm, 0); | |
529 | if (new_end > old_start) { | |
530 | /* | |
531 | * when the old and new regions overlap clear from new_end. | |
532 | */ | |
42b77728 | 533 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
534 | vma->vm_next ? vma->vm_next->vm_start : 0); |
535 | } else { | |
536 | /* | |
537 | * otherwise, clean from old_start; this is done to not touch | |
538 | * the address space in [new_end, old_start) some architectures | |
539 | * have constraints on va-space that make this illegal (IA64) - | |
540 | * for the others its just a little faster. | |
541 | */ | |
42b77728 | 542 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 543 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 544 | } |
b6a2fea3 OW |
545 | tlb_finish_mmu(tlb, new_end, old_end); |
546 | ||
547 | /* | |
548 | * shrink the vma to just the new range. | |
549 | */ | |
550 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
551 | ||
552 | return 0; | |
1da177e4 LT |
553 | } |
554 | ||
555 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
556 | ||
b6a2fea3 OW |
557 | /* |
558 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
559 | * the stack is optionally relocated, and some extra space is added. | |
560 | */ | |
1da177e4 LT |
561 | int setup_arg_pages(struct linux_binprm *bprm, |
562 | unsigned long stack_top, | |
563 | int executable_stack) | |
564 | { | |
b6a2fea3 OW |
565 | unsigned long ret; |
566 | unsigned long stack_shift; | |
1da177e4 | 567 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
568 | struct vm_area_struct *vma = bprm->vma; |
569 | struct vm_area_struct *prev = NULL; | |
570 | unsigned long vm_flags; | |
571 | unsigned long stack_base; | |
1da177e4 LT |
572 | |
573 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
574 | /* Limit stack size to 1GB */ |
575 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
576 | if (stack_base > (1 << 30)) | |
577 | stack_base = 1 << 30; | |
1da177e4 | 578 | |
b6a2fea3 OW |
579 | /* Make sure we didn't let the argument array grow too large. */ |
580 | if (vma->vm_end - vma->vm_start > stack_base) | |
581 | return -ENOMEM; | |
1da177e4 | 582 | |
b6a2fea3 | 583 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 584 | |
b6a2fea3 OW |
585 | stack_shift = vma->vm_start - stack_base; |
586 | mm->arg_start = bprm->p - stack_shift; | |
587 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 588 | #else |
b6a2fea3 OW |
589 | stack_top = arch_align_stack(stack_top); |
590 | stack_top = PAGE_ALIGN(stack_top); | |
591 | stack_shift = vma->vm_end - stack_top; | |
592 | ||
593 | bprm->p -= stack_shift; | |
1da177e4 | 594 | mm->arg_start = bprm->p; |
1da177e4 LT |
595 | #endif |
596 | ||
1da177e4 | 597 | if (bprm->loader) |
b6a2fea3 OW |
598 | bprm->loader -= stack_shift; |
599 | bprm->exec -= stack_shift; | |
1da177e4 | 600 | |
1da177e4 | 601 | down_write(&mm->mmap_sem); |
96a8e13e | 602 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
603 | |
604 | /* | |
605 | * Adjust stack execute permissions; explicitly enable for | |
606 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
607 | * (arch default) otherwise. | |
608 | */ | |
609 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
610 | vm_flags |= VM_EXEC; | |
611 | else if (executable_stack == EXSTACK_DISABLE_X) | |
612 | vm_flags &= ~VM_EXEC; | |
613 | vm_flags |= mm->def_flags; | |
614 | ||
615 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
616 | vm_flags); | |
617 | if (ret) | |
618 | goto out_unlock; | |
619 | BUG_ON(prev != vma); | |
620 | ||
621 | /* Move stack pages down in memory. */ | |
622 | if (stack_shift) { | |
623 | ret = shift_arg_pages(vma, stack_shift); | |
624 | if (ret) { | |
1da177e4 | 625 | up_write(&mm->mmap_sem); |
1da177e4 LT |
626 | return ret; |
627 | } | |
1da177e4 LT |
628 | } |
629 | ||
b6a2fea3 OW |
630 | #ifdef CONFIG_STACK_GROWSUP |
631 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
632 | #else | |
633 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
634 | #endif | |
635 | ret = expand_stack(vma, stack_base); | |
636 | if (ret) | |
637 | ret = -EFAULT; | |
638 | ||
639 | out_unlock: | |
1da177e4 | 640 | up_write(&mm->mmap_sem); |
1da177e4 LT |
641 | return 0; |
642 | } | |
1da177e4 LT |
643 | EXPORT_SYMBOL(setup_arg_pages); |
644 | ||
1da177e4 LT |
645 | #endif /* CONFIG_MMU */ |
646 | ||
647 | struct file *open_exec(const char *name) | |
648 | { | |
1da177e4 | 649 | struct file *file; |
e56b6a5d | 650 | int err; |
1da177e4 | 651 | |
6e8341a1 AV |
652 | file = do_filp_open(AT_FDCWD, name, |
653 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
654 | MAY_EXEC | MAY_OPEN); | |
655 | if (IS_ERR(file)) | |
e56b6a5d CH |
656 | goto out; |
657 | ||
658 | err = -EACCES; | |
6e8341a1 AV |
659 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
660 | goto exit; | |
e56b6a5d | 661 | |
6e8341a1 AV |
662 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
663 | goto exit; | |
e56b6a5d | 664 | |
6110e3ab EP |
665 | fsnotify_open(file->f_path.dentry); |
666 | ||
e56b6a5d | 667 | err = deny_write_access(file); |
6e8341a1 AV |
668 | if (err) |
669 | goto exit; | |
1da177e4 | 670 | |
6e8341a1 | 671 | out: |
e56b6a5d CH |
672 | return file; |
673 | ||
6e8341a1 AV |
674 | exit: |
675 | fput(file); | |
e56b6a5d CH |
676 | return ERR_PTR(err); |
677 | } | |
1da177e4 LT |
678 | EXPORT_SYMBOL(open_exec); |
679 | ||
680 | int kernel_read(struct file *file, unsigned long offset, | |
681 | char *addr, unsigned long count) | |
682 | { | |
683 | mm_segment_t old_fs; | |
684 | loff_t pos = offset; | |
685 | int result; | |
686 | ||
687 | old_fs = get_fs(); | |
688 | set_fs(get_ds()); | |
689 | /* The cast to a user pointer is valid due to the set_fs() */ | |
690 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
691 | set_fs(old_fs); | |
692 | return result; | |
693 | } | |
694 | ||
695 | EXPORT_SYMBOL(kernel_read); | |
696 | ||
697 | static int exec_mmap(struct mm_struct *mm) | |
698 | { | |
699 | struct task_struct *tsk; | |
700 | struct mm_struct * old_mm, *active_mm; | |
701 | ||
702 | /* Notify parent that we're no longer interested in the old VM */ | |
703 | tsk = current; | |
704 | old_mm = current->mm; | |
705 | mm_release(tsk, old_mm); | |
706 | ||
707 | if (old_mm) { | |
708 | /* | |
709 | * Make sure that if there is a core dump in progress | |
710 | * for the old mm, we get out and die instead of going | |
711 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 712 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
713 | */ |
714 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 715 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
716 | up_read(&old_mm->mmap_sem); |
717 | return -EINTR; | |
718 | } | |
719 | } | |
720 | task_lock(tsk); | |
721 | active_mm = tsk->active_mm; | |
722 | tsk->mm = mm; | |
723 | tsk->active_mm = mm; | |
724 | activate_mm(active_mm, mm); | |
725 | task_unlock(tsk); | |
726 | arch_pick_mmap_layout(mm); | |
727 | if (old_mm) { | |
728 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 729 | BUG_ON(active_mm != old_mm); |
31a78f23 | 730 | mm_update_next_owner(old_mm); |
1da177e4 LT |
731 | mmput(old_mm); |
732 | return 0; | |
733 | } | |
734 | mmdrop(active_mm); | |
735 | return 0; | |
736 | } | |
737 | ||
738 | /* | |
739 | * This function makes sure the current process has its own signal table, | |
740 | * so that flush_signal_handlers can later reset the handlers without | |
741 | * disturbing other processes. (Other processes might share the signal | |
742 | * table via the CLONE_SIGHAND option to clone().) | |
743 | */ | |
858119e1 | 744 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
745 | { |
746 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 747 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 LT |
748 | spinlock_t *lock = &oldsighand->siglock; |
749 | int count; | |
750 | ||
aafe6c2a | 751 | if (thread_group_empty(tsk)) |
1da177e4 LT |
752 | goto no_thread_group; |
753 | ||
754 | /* | |
755 | * Kill all other threads in the thread group. | |
1da177e4 | 756 | */ |
1da177e4 | 757 | spin_lock_irq(lock); |
ed5d2cac | 758 | if (signal_group_exit(sig)) { |
1da177e4 LT |
759 | /* |
760 | * Another group action in progress, just | |
761 | * return so that the signal is processed. | |
762 | */ | |
763 | spin_unlock_irq(lock); | |
1da177e4 LT |
764 | return -EAGAIN; |
765 | } | |
ed5d2cac | 766 | sig->group_exit_task = tsk; |
aafe6c2a | 767 | zap_other_threads(tsk); |
1da177e4 | 768 | |
fea9d175 ON |
769 | /* Account for the thread group leader hanging around: */ |
770 | count = thread_group_leader(tsk) ? 1 : 2; | |
6db840fa | 771 | sig->notify_count = count; |
1da177e4 | 772 | while (atomic_read(&sig->count) > count) { |
1da177e4 LT |
773 | __set_current_state(TASK_UNINTERRUPTIBLE); |
774 | spin_unlock_irq(lock); | |
775 | schedule(); | |
776 | spin_lock_irq(lock); | |
777 | } | |
1da177e4 LT |
778 | spin_unlock_irq(lock); |
779 | ||
780 | /* | |
781 | * At this point all other threads have exited, all we have to | |
782 | * do is to wait for the thread group leader to become inactive, | |
783 | * and to assume its PID: | |
784 | */ | |
aafe6c2a | 785 | if (!thread_group_leader(tsk)) { |
8187926b | 786 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 787 | |
2800d8d1 | 788 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
789 | for (;;) { |
790 | write_lock_irq(&tasklist_lock); | |
791 | if (likely(leader->exit_state)) | |
792 | break; | |
793 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
794 | write_unlock_irq(&tasklist_lock); | |
795 | schedule(); | |
796 | } | |
1da177e4 | 797 | |
f5e90281 RM |
798 | /* |
799 | * The only record we have of the real-time age of a | |
800 | * process, regardless of execs it's done, is start_time. | |
801 | * All the past CPU time is accumulated in signal_struct | |
802 | * from sister threads now dead. But in this non-leader | |
803 | * exec, nothing survives from the original leader thread, | |
804 | * whose birth marks the true age of this process now. | |
805 | * When we take on its identity by switching to its PID, we | |
806 | * also take its birthdate (always earlier than our own). | |
807 | */ | |
aafe6c2a | 808 | tsk->start_time = leader->start_time; |
f5e90281 | 809 | |
bac0abd6 PE |
810 | BUG_ON(!same_thread_group(leader, tsk)); |
811 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
812 | /* |
813 | * An exec() starts a new thread group with the | |
814 | * TGID of the previous thread group. Rehash the | |
815 | * two threads with a switched PID, and release | |
816 | * the former thread group leader: | |
817 | */ | |
d73d6529 EB |
818 | |
819 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
820 | * The old leader becomes a thread of the this thread group. |
821 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
822 | * is called. Odd but simple and correct. |
823 | */ | |
aafe6c2a EB |
824 | detach_pid(tsk, PIDTYPE_PID); |
825 | tsk->pid = leader->pid; | |
3743ca05 | 826 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
827 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
828 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
829 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 830 | |
aafe6c2a EB |
831 | tsk->group_leader = tsk; |
832 | leader->group_leader = tsk; | |
de12a787 | 833 | |
aafe6c2a | 834 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
835 | |
836 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
837 | leader->exit_state = EXIT_DEAD; | |
1da177e4 | 838 | write_unlock_irq(&tasklist_lock); |
8187926b ON |
839 | |
840 | release_task(leader); | |
ed5d2cac | 841 | } |
1da177e4 | 842 | |
6db840fa ON |
843 | sig->group_exit_task = NULL; |
844 | sig->notify_count = 0; | |
1da177e4 LT |
845 | |
846 | no_thread_group: | |
1da177e4 | 847 | exit_itimers(sig); |
cbaffba1 | 848 | flush_itimer_signals(); |
329f7dba | 849 | |
b2c903b8 ON |
850 | if (atomic_read(&oldsighand->count) != 1) { |
851 | struct sighand_struct *newsighand; | |
1da177e4 | 852 | /* |
b2c903b8 ON |
853 | * This ->sighand is shared with the CLONE_SIGHAND |
854 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 855 | */ |
b2c903b8 ON |
856 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
857 | if (!newsighand) | |
858 | return -ENOMEM; | |
859 | ||
1da177e4 LT |
860 | atomic_set(&newsighand->count, 1); |
861 | memcpy(newsighand->action, oldsighand->action, | |
862 | sizeof(newsighand->action)); | |
863 | ||
864 | write_lock_irq(&tasklist_lock); | |
865 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 866 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
867 | spin_unlock(&oldsighand->siglock); |
868 | write_unlock_irq(&tasklist_lock); | |
869 | ||
fba2afaa | 870 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
871 | } |
872 | ||
aafe6c2a | 873 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
874 | return 0; |
875 | } | |
0840a90d | 876 | |
1da177e4 LT |
877 | /* |
878 | * These functions flushes out all traces of the currently running executable | |
879 | * so that a new one can be started | |
880 | */ | |
858119e1 | 881 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
882 | { |
883 | long j = -1; | |
badf1662 | 884 | struct fdtable *fdt; |
1da177e4 LT |
885 | |
886 | spin_lock(&files->file_lock); | |
887 | for (;;) { | |
888 | unsigned long set, i; | |
889 | ||
890 | j++; | |
891 | i = j * __NFDBITS; | |
badf1662 | 892 | fdt = files_fdtable(files); |
bbea9f69 | 893 | if (i >= fdt->max_fds) |
1da177e4 | 894 | break; |
badf1662 | 895 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
896 | if (!set) |
897 | continue; | |
badf1662 | 898 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
899 | spin_unlock(&files->file_lock); |
900 | for ( ; set ; i++,set >>= 1) { | |
901 | if (set & 1) { | |
902 | sys_close(i); | |
903 | } | |
904 | } | |
905 | spin_lock(&files->file_lock); | |
906 | ||
907 | } | |
908 | spin_unlock(&files->file_lock); | |
909 | } | |
910 | ||
59714d65 | 911 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
912 | { |
913 | /* buf must be at least sizeof(tsk->comm) in size */ | |
914 | task_lock(tsk); | |
915 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
916 | task_unlock(tsk); | |
59714d65 | 917 | return buf; |
1da177e4 LT |
918 | } |
919 | ||
920 | void set_task_comm(struct task_struct *tsk, char *buf) | |
921 | { | |
922 | task_lock(tsk); | |
923 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
924 | task_unlock(tsk); | |
925 | } | |
926 | ||
927 | int flush_old_exec(struct linux_binprm * bprm) | |
928 | { | |
929 | char * name; | |
930 | int i, ch, retval; | |
1da177e4 LT |
931 | char tcomm[sizeof(current->comm)]; |
932 | ||
933 | /* | |
934 | * Make sure we have a private signal table and that | |
935 | * we are unassociated from the previous thread group. | |
936 | */ | |
937 | retval = de_thread(current); | |
938 | if (retval) | |
939 | goto out; | |
940 | ||
925d1c40 MH |
941 | set_mm_exe_file(bprm->mm, bprm->file); |
942 | ||
1da177e4 LT |
943 | /* |
944 | * Release all of the old mmap stuff | |
945 | */ | |
946 | retval = exec_mmap(bprm->mm); | |
947 | if (retval) | |
fd8328be | 948 | goto out; |
1da177e4 LT |
949 | |
950 | bprm->mm = NULL; /* We're using it now */ | |
951 | ||
952 | /* This is the point of no return */ | |
1da177e4 LT |
953 | current->sas_ss_sp = current->sas_ss_size = 0; |
954 | ||
da9592ed | 955 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
6c5d5238 | 956 | set_dumpable(current->mm, 1); |
d6e71144 | 957 | else |
6c5d5238 | 958 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 959 | |
1da177e4 | 960 | name = bprm->filename; |
36772092 PBG |
961 | |
962 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
963 | for (i=0; (ch = *(name++)) != '\0';) { |
964 | if (ch == '/') | |
36772092 | 965 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
966 | else |
967 | if (i < (sizeof(tcomm) - 1)) | |
968 | tcomm[i++] = ch; | |
969 | } | |
970 | tcomm[i] = '\0'; | |
971 | set_task_comm(current, tcomm); | |
972 | ||
973 | current->flags &= ~PF_RANDOMIZE; | |
974 | flush_thread(); | |
975 | ||
0551fbd2 BH |
976 | /* Set the new mm task size. We have to do that late because it may |
977 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
978 | * some architectures like powerpc | |
979 | */ | |
980 | current->mm->task_size = TASK_SIZE; | |
981 | ||
a6f76f23 DH |
982 | /* install the new credentials */ |
983 | if (bprm->cred->uid != current_euid() || | |
984 | bprm->cred->gid != current_egid()) { | |
d2d56c5f MH |
985 | current->pdeath_signal = 0; |
986 | } else if (file_permission(bprm->file, MAY_READ) || | |
a6f76f23 | 987 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
6c5d5238 | 988 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
989 | } |
990 | ||
a6f76f23 DH |
991 | current->personality &= ~bprm->per_clear; |
992 | ||
1da177e4 LT |
993 | /* An exec changes our domain. We are no longer part of the thread |
994 | group */ | |
995 | ||
996 | current->self_exec_id++; | |
997 | ||
998 | flush_signal_handlers(current, 0); | |
999 | flush_old_files(current->files); | |
1000 | ||
1001 | return 0; | |
1002 | ||
1da177e4 LT |
1003 | out: |
1004 | return retval; | |
1005 | } | |
1006 | ||
1007 | EXPORT_SYMBOL(flush_old_exec); | |
1008 | ||
a6f76f23 DH |
1009 | /* |
1010 | * install the new credentials for this executable | |
1011 | */ | |
1012 | void install_exec_creds(struct linux_binprm *bprm) | |
1013 | { | |
1014 | security_bprm_committing_creds(bprm); | |
1015 | ||
1016 | commit_creds(bprm->cred); | |
1017 | bprm->cred = NULL; | |
1018 | ||
1019 | /* cred_exec_mutex must be held at least to this point to prevent | |
1020 | * ptrace_attach() from altering our determination of the task's | |
1021 | * credentials; any time after this it may be unlocked */ | |
1022 | ||
1023 | security_bprm_committed_creds(bprm); | |
1024 | } | |
1025 | EXPORT_SYMBOL(install_exec_creds); | |
1026 | ||
1027 | /* | |
1028 | * determine how safe it is to execute the proposed program | |
1029 | * - the caller must hold current->cred_exec_mutex to protect against | |
1030 | * PTRACE_ATTACH | |
1031 | */ | |
498052bb | 1032 | int check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1033 | { |
0bf2f3ae | 1034 | struct task_struct *p = current, *t; |
f1191b50 | 1035 | unsigned n_fs; |
498052bb | 1036 | int res = 0; |
a6f76f23 DH |
1037 | |
1038 | bprm->unsafe = tracehook_unsafe_exec(p); | |
1039 | ||
0bf2f3ae | 1040 | n_fs = 1; |
498052bb | 1041 | write_lock(&p->fs->lock); |
437f7fdb | 1042 | rcu_read_lock(); |
0bf2f3ae DH |
1043 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
1044 | if (t->fs == p->fs) | |
1045 | n_fs++; | |
0bf2f3ae | 1046 | } |
437f7fdb | 1047 | rcu_read_unlock(); |
0bf2f3ae | 1048 | |
f1191b50 | 1049 | if (p->fs->users > n_fs) { |
a6f76f23 | 1050 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
498052bb | 1051 | } else { |
8c652f96 ON |
1052 | res = -EAGAIN; |
1053 | if (!p->fs->in_exec) { | |
1054 | p->fs->in_exec = 1; | |
1055 | res = 1; | |
1056 | } | |
498052bb | 1057 | } |
498052bb AV |
1058 | write_unlock(&p->fs->lock); |
1059 | ||
1060 | return res; | |
a6f76f23 DH |
1061 | } |
1062 | ||
1da177e4 LT |
1063 | /* |
1064 | * Fill the binprm structure from the inode. | |
1065 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
a6f76f23 DH |
1066 | * |
1067 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1068 | */ |
1069 | int prepare_binprm(struct linux_binprm *bprm) | |
1070 | { | |
a6f76f23 | 1071 | umode_t mode; |
0f7fc9e4 | 1072 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1073 | int retval; |
1074 | ||
1075 | mode = inode->i_mode; | |
1da177e4 LT |
1076 | if (bprm->file->f_op == NULL) |
1077 | return -EACCES; | |
1078 | ||
a6f76f23 DH |
1079 | /* clear any previous set[ug]id data from a previous binary */ |
1080 | bprm->cred->euid = current_euid(); | |
1081 | bprm->cred->egid = current_egid(); | |
1da177e4 | 1082 | |
a6f76f23 | 1083 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1084 | /* Set-uid? */ |
1085 | if (mode & S_ISUID) { | |
a6f76f23 DH |
1086 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1087 | bprm->cred->euid = inode->i_uid; | |
1da177e4 LT |
1088 | } |
1089 | ||
1090 | /* Set-gid? */ | |
1091 | /* | |
1092 | * If setgid is set but no group execute bit then this | |
1093 | * is a candidate for mandatory locking, not a setgid | |
1094 | * executable. | |
1095 | */ | |
1096 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
a6f76f23 DH |
1097 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1098 | bprm->cred->egid = inode->i_gid; | |
1da177e4 LT |
1099 | } |
1100 | } | |
1101 | ||
1102 | /* fill in binprm security blob */ | |
a6f76f23 | 1103 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1104 | if (retval) |
1105 | return retval; | |
a6f76f23 | 1106 | bprm->cred_prepared = 1; |
1da177e4 | 1107 | |
a6f76f23 DH |
1108 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1109 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1110 | } |
1111 | ||
1112 | EXPORT_SYMBOL(prepare_binprm); | |
1113 | ||
4fc75ff4 NP |
1114 | /* |
1115 | * Arguments are '\0' separated strings found at the location bprm->p | |
1116 | * points to; chop off the first by relocating brpm->p to right after | |
1117 | * the first '\0' encountered. | |
1118 | */ | |
b6a2fea3 | 1119 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1120 | { |
b6a2fea3 OW |
1121 | int ret = 0; |
1122 | unsigned long offset; | |
1123 | char *kaddr; | |
1124 | struct page *page; | |
4fc75ff4 | 1125 | |
b6a2fea3 OW |
1126 | if (!bprm->argc) |
1127 | return 0; | |
1da177e4 | 1128 | |
b6a2fea3 OW |
1129 | do { |
1130 | offset = bprm->p & ~PAGE_MASK; | |
1131 | page = get_arg_page(bprm, bprm->p, 0); | |
1132 | if (!page) { | |
1133 | ret = -EFAULT; | |
1134 | goto out; | |
1135 | } | |
1136 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1137 | |
b6a2fea3 OW |
1138 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1139 | offset++, bprm->p++) | |
1140 | ; | |
4fc75ff4 | 1141 | |
b6a2fea3 OW |
1142 | kunmap_atomic(kaddr, KM_USER0); |
1143 | put_arg_page(page); | |
4fc75ff4 | 1144 | |
b6a2fea3 OW |
1145 | if (offset == PAGE_SIZE) |
1146 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1147 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1148 | |
b6a2fea3 OW |
1149 | bprm->p++; |
1150 | bprm->argc--; | |
1151 | ret = 0; | |
4fc75ff4 | 1152 | |
b6a2fea3 OW |
1153 | out: |
1154 | return ret; | |
1da177e4 | 1155 | } |
1da177e4 LT |
1156 | EXPORT_SYMBOL(remove_arg_zero); |
1157 | ||
1158 | /* | |
1159 | * cycle the list of binary formats handler, until one recognizes the image | |
1160 | */ | |
1161 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1162 | { | |
85f33466 | 1163 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1164 | int try,retval; |
1165 | struct linux_binfmt *fmt; | |
1da177e4 | 1166 | |
1da177e4 | 1167 | retval = security_bprm_check(bprm); |
6146f0d5 MZ |
1168 | if (retval) |
1169 | return retval; | |
1170 | retval = ima_bprm_check(bprm); | |
1da177e4 LT |
1171 | if (retval) |
1172 | return retval; | |
1173 | ||
1174 | /* kernel module loader fixup */ | |
1175 | /* so we don't try to load run modprobe in kernel space. */ | |
1176 | set_fs(USER_DS); | |
473ae30b AV |
1177 | |
1178 | retval = audit_bprm(bprm); | |
1179 | if (retval) | |
1180 | return retval; | |
1181 | ||
1da177e4 LT |
1182 | retval = -ENOENT; |
1183 | for (try=0; try<2; try++) { | |
1184 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1185 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1186 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1187 | if (!fn) | |
1188 | continue; | |
1189 | if (!try_module_get(fmt->module)) | |
1190 | continue; | |
1191 | read_unlock(&binfmt_lock); | |
1192 | retval = fn(bprm, regs); | |
85f33466 RM |
1193 | /* |
1194 | * Restore the depth counter to its starting value | |
1195 | * in this call, so we don't have to rely on every | |
1196 | * load_binary function to restore it on return. | |
1197 | */ | |
1198 | bprm->recursion_depth = depth; | |
1da177e4 | 1199 | if (retval >= 0) { |
85f33466 RM |
1200 | if (depth == 0) |
1201 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1202 | put_binfmt(fmt); |
1203 | allow_write_access(bprm->file); | |
1204 | if (bprm->file) | |
1205 | fput(bprm->file); | |
1206 | bprm->file = NULL; | |
1207 | current->did_exec = 1; | |
9f46080c | 1208 | proc_exec_connector(current); |
1da177e4 LT |
1209 | return retval; |
1210 | } | |
1211 | read_lock(&binfmt_lock); | |
1212 | put_binfmt(fmt); | |
1213 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1214 | break; | |
1215 | if (!bprm->file) { | |
1216 | read_unlock(&binfmt_lock); | |
1217 | return retval; | |
1218 | } | |
1219 | } | |
1220 | read_unlock(&binfmt_lock); | |
1221 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1222 | break; | |
5f4123be JB |
1223 | #ifdef CONFIG_MODULES |
1224 | } else { | |
1da177e4 LT |
1225 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1226 | if (printable(bprm->buf[0]) && | |
1227 | printable(bprm->buf[1]) && | |
1228 | printable(bprm->buf[2]) && | |
1229 | printable(bprm->buf[3])) | |
1230 | break; /* -ENOEXEC */ | |
1231 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1232 | #endif | |
1233 | } | |
1234 | } | |
1235 | return retval; | |
1236 | } | |
1237 | ||
1238 | EXPORT_SYMBOL(search_binary_handler); | |
1239 | ||
08a6fac1 AV |
1240 | void free_bprm(struct linux_binprm *bprm) |
1241 | { | |
1242 | free_arg_pages(bprm); | |
a6f76f23 DH |
1243 | if (bprm->cred) |
1244 | abort_creds(bprm->cred); | |
08a6fac1 AV |
1245 | kfree(bprm); |
1246 | } | |
1247 | ||
1da177e4 LT |
1248 | /* |
1249 | * sys_execve() executes a new program. | |
1250 | */ | |
1251 | int do_execve(char * filename, | |
1252 | char __user *__user *argv, | |
1253 | char __user *__user *envp, | |
1254 | struct pt_regs * regs) | |
1255 | { | |
1256 | struct linux_binprm *bprm; | |
1257 | struct file *file; | |
3b125388 | 1258 | struct files_struct *displaced; |
8c652f96 | 1259 | bool clear_in_exec; |
1da177e4 | 1260 | int retval; |
1da177e4 | 1261 | |
3b125388 | 1262 | retval = unshare_files(&displaced); |
fd8328be AV |
1263 | if (retval) |
1264 | goto out_ret; | |
1265 | ||
1da177e4 | 1266 | retval = -ENOMEM; |
11b0b5ab | 1267 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1268 | if (!bprm) |
fd8328be | 1269 | goto out_files; |
1da177e4 | 1270 | |
a6f76f23 DH |
1271 | retval = mutex_lock_interruptible(¤t->cred_exec_mutex); |
1272 | if (retval < 0) | |
1273 | goto out_free; | |
f9ce1f1c | 1274 | current->in_execve = 1; |
a6f76f23 DH |
1275 | |
1276 | retval = -ENOMEM; | |
1277 | bprm->cred = prepare_exec_creds(); | |
1278 | if (!bprm->cred) | |
1279 | goto out_unlock; | |
498052bb AV |
1280 | |
1281 | retval = check_unsafe_exec(bprm); | |
8c652f96 | 1282 | if (retval < 0) |
498052bb | 1283 | goto out_unlock; |
8c652f96 | 1284 | clear_in_exec = retval; |
a6f76f23 | 1285 | |
1da177e4 LT |
1286 | file = open_exec(filename); |
1287 | retval = PTR_ERR(file); | |
1288 | if (IS_ERR(file)) | |
498052bb | 1289 | goto out_unmark; |
1da177e4 LT |
1290 | |
1291 | sched_exec(); | |
1292 | ||
1da177e4 LT |
1293 | bprm->file = file; |
1294 | bprm->filename = filename; | |
1295 | bprm->interp = filename; | |
1da177e4 | 1296 | |
b6a2fea3 OW |
1297 | retval = bprm_mm_init(bprm); |
1298 | if (retval) | |
1299 | goto out_file; | |
1da177e4 | 1300 | |
b6a2fea3 | 1301 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1302 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1303 | goto out; |
1da177e4 | 1304 | |
b6a2fea3 | 1305 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1306 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1307 | goto out; |
1308 | ||
1309 | retval = prepare_binprm(bprm); | |
1310 | if (retval < 0) | |
1311 | goto out; | |
1312 | ||
1313 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1314 | if (retval < 0) | |
1315 | goto out; | |
1316 | ||
1317 | bprm->exec = bprm->p; | |
1318 | retval = copy_strings(bprm->envc, envp, bprm); | |
1319 | if (retval < 0) | |
1320 | goto out; | |
1321 | ||
1322 | retval = copy_strings(bprm->argc, argv, bprm); | |
1323 | if (retval < 0) | |
1324 | goto out; | |
1325 | ||
7b34e428 | 1326 | current->flags &= ~PF_KTHREAD; |
1da177e4 | 1327 | retval = search_binary_handler(bprm,regs); |
a6f76f23 DH |
1328 | if (retval < 0) |
1329 | goto out; | |
1da177e4 | 1330 | |
a6f76f23 | 1331 | /* execve succeeded */ |
498052bb | 1332 | current->fs->in_exec = 0; |
f9ce1f1c | 1333 | current->in_execve = 0; |
a6f76f23 DH |
1334 | mutex_unlock(¤t->cred_exec_mutex); |
1335 | acct_update_integrals(current); | |
1336 | free_bprm(bprm); | |
1337 | if (displaced) | |
1338 | put_files_struct(displaced); | |
1339 | return retval; | |
1da177e4 | 1340 | |
a6f76f23 | 1341 | out: |
1da177e4 | 1342 | if (bprm->mm) |
b6a2fea3 | 1343 | mmput (bprm->mm); |
1da177e4 LT |
1344 | |
1345 | out_file: | |
1346 | if (bprm->file) { | |
1347 | allow_write_access(bprm->file); | |
1348 | fput(bprm->file); | |
1349 | } | |
a6f76f23 | 1350 | |
498052bb | 1351 | out_unmark: |
8c652f96 ON |
1352 | if (clear_in_exec) |
1353 | current->fs->in_exec = 0; | |
498052bb | 1354 | |
a6f76f23 | 1355 | out_unlock: |
f9ce1f1c | 1356 | current->in_execve = 0; |
a6f76f23 DH |
1357 | mutex_unlock(¤t->cred_exec_mutex); |
1358 | ||
1359 | out_free: | |
08a6fac1 | 1360 | free_bprm(bprm); |
1da177e4 | 1361 | |
fd8328be | 1362 | out_files: |
3b125388 AV |
1363 | if (displaced) |
1364 | reset_files_struct(displaced); | |
1da177e4 LT |
1365 | out_ret: |
1366 | return retval; | |
1367 | } | |
1368 | ||
1369 | int set_binfmt(struct linux_binfmt *new) | |
1370 | { | |
1371 | struct linux_binfmt *old = current->binfmt; | |
1372 | ||
1373 | if (new) { | |
1374 | if (!try_module_get(new->module)) | |
1375 | return -1; | |
1376 | } | |
1377 | current->binfmt = new; | |
1378 | if (old) | |
1379 | module_put(old->module); | |
1380 | return 0; | |
1381 | } | |
1382 | ||
1383 | EXPORT_SYMBOL(set_binfmt); | |
1384 | ||
1da177e4 LT |
1385 | /* format_corename will inspect the pattern parameter, and output a |
1386 | * name into corename, which must have space for at least | |
1387 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1388 | */ | |
6409324b | 1389 | static int format_corename(char *corename, long signr) |
1da177e4 | 1390 | { |
86a264ab | 1391 | const struct cred *cred = current_cred(); |
565b9b14 ON |
1392 | const char *pat_ptr = core_pattern; |
1393 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 LT |
1394 | char *out_ptr = corename; |
1395 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1396 | int rc; | |
1397 | int pid_in_pattern = 0; | |
1398 | ||
1399 | /* Repeat as long as we have more pattern to process and more output | |
1400 | space */ | |
1401 | while (*pat_ptr) { | |
1402 | if (*pat_ptr != '%') { | |
1403 | if (out_ptr == out_end) | |
1404 | goto out; | |
1405 | *out_ptr++ = *pat_ptr++; | |
1406 | } else { | |
1407 | switch (*++pat_ptr) { | |
1408 | case 0: | |
1409 | goto out; | |
1410 | /* Double percent, output one percent */ | |
1411 | case '%': | |
1412 | if (out_ptr == out_end) | |
1413 | goto out; | |
1414 | *out_ptr++ = '%'; | |
1415 | break; | |
1416 | /* pid */ | |
1417 | case 'p': | |
1418 | pid_in_pattern = 1; | |
1419 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1420 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1421 | if (rc > out_end - out_ptr) |
1422 | goto out; | |
1423 | out_ptr += rc; | |
1424 | break; | |
1425 | /* uid */ | |
1426 | case 'u': | |
1427 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1428 | "%d", cred->uid); |
1da177e4 LT |
1429 | if (rc > out_end - out_ptr) |
1430 | goto out; | |
1431 | out_ptr += rc; | |
1432 | break; | |
1433 | /* gid */ | |
1434 | case 'g': | |
1435 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1436 | "%d", cred->gid); |
1da177e4 LT |
1437 | if (rc > out_end - out_ptr) |
1438 | goto out; | |
1439 | out_ptr += rc; | |
1440 | break; | |
1441 | /* signal that caused the coredump */ | |
1442 | case 's': | |
1443 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1444 | "%ld", signr); | |
1445 | if (rc > out_end - out_ptr) | |
1446 | goto out; | |
1447 | out_ptr += rc; | |
1448 | break; | |
1449 | /* UNIX time of coredump */ | |
1450 | case 't': { | |
1451 | struct timeval tv; | |
1452 | do_gettimeofday(&tv); | |
1453 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1454 | "%lu", tv.tv_sec); | |
1455 | if (rc > out_end - out_ptr) | |
1456 | goto out; | |
1457 | out_ptr += rc; | |
1458 | break; | |
1459 | } | |
1460 | /* hostname */ | |
1461 | case 'h': | |
1462 | down_read(&uts_sem); | |
1463 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1464 | "%s", utsname()->nodename); |
1da177e4 LT |
1465 | up_read(&uts_sem); |
1466 | if (rc > out_end - out_ptr) | |
1467 | goto out; | |
1468 | out_ptr += rc; | |
1469 | break; | |
1470 | /* executable */ | |
1471 | case 'e': | |
1472 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1473 | "%s", current->comm); | |
1474 | if (rc > out_end - out_ptr) | |
1475 | goto out; | |
1476 | out_ptr += rc; | |
1477 | break; | |
74aadce9 NH |
1478 | /* core limit size */ |
1479 | case 'c': | |
1480 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1481 | "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); | |
1482 | if (rc > out_end - out_ptr) | |
1483 | goto out; | |
1484 | out_ptr += rc; | |
1485 | break; | |
1da177e4 LT |
1486 | default: |
1487 | break; | |
1488 | } | |
1489 | ++pat_ptr; | |
1490 | } | |
1491 | } | |
1492 | /* Backward compatibility with core_uses_pid: | |
1493 | * | |
1494 | * If core_pattern does not include a %p (as is the default) | |
1495 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1496 | * the filename. Do not do this for piped commands. */ |
6409324b | 1497 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1da177e4 | 1498 | rc = snprintf(out_ptr, out_end - out_ptr, |
b488893a | 1499 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1500 | if (rc > out_end - out_ptr) |
1501 | goto out; | |
1502 | out_ptr += rc; | |
1503 | } | |
c4bbafda | 1504 | out: |
1da177e4 | 1505 | *out_ptr = 0; |
c4bbafda | 1506 | return ispipe; |
1da177e4 LT |
1507 | } |
1508 | ||
8cd9c249 | 1509 | static int zap_process(struct task_struct *start) |
aceecc04 ON |
1510 | { |
1511 | struct task_struct *t; | |
8cd9c249 | 1512 | int nr = 0; |
281de339 | 1513 | |
d5f70c00 ON |
1514 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1515 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1516 | |
1517 | t = start; | |
1518 | do { | |
1519 | if (t != current && t->mm) { | |
281de339 ON |
1520 | sigaddset(&t->pending.signal, SIGKILL); |
1521 | signal_wake_up(t, 1); | |
8cd9c249 | 1522 | nr++; |
aceecc04 | 1523 | } |
e4901f92 | 1524 | } while_each_thread(start, t); |
8cd9c249 ON |
1525 | |
1526 | return nr; | |
aceecc04 ON |
1527 | } |
1528 | ||
dcf560c5 | 1529 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1530 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1531 | { |
1532 | struct task_struct *g, *p; | |
5debfa6d | 1533 | unsigned long flags; |
8cd9c249 | 1534 | int nr = -EAGAIN; |
dcf560c5 ON |
1535 | |
1536 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1537 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1538 | mm->core_state = core_state; |
dcf560c5 | 1539 | tsk->signal->group_exit_code = exit_code; |
8cd9c249 | 1540 | nr = zap_process(tsk); |
1da177e4 | 1541 | } |
dcf560c5 | 1542 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1543 | if (unlikely(nr < 0)) |
1544 | return nr; | |
1da177e4 | 1545 | |
8cd9c249 | 1546 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1547 | goto done; |
e4901f92 ON |
1548 | /* |
1549 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1550 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1551 | * lock, but this is safe wrt: |
1552 | * | |
1553 | * fork: | |
1554 | * None of sub-threads can fork after zap_process(leader). All | |
1555 | * processes which were created before this point should be | |
1556 | * visible to zap_threads() because copy_process() adds the new | |
1557 | * process to the tail of init_task.tasks list, and lock/unlock | |
1558 | * of ->siglock provides a memory barrier. | |
1559 | * | |
1560 | * do_exit: | |
1561 | * The caller holds mm->mmap_sem. This means that the task which | |
1562 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1563 | * its ->mm. | |
1564 | * | |
1565 | * de_thread: | |
1566 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1567 | * we must see either old or new leader, this does not matter. | |
1568 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1569 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1570 | * it can't fail. | |
1571 | * | |
1572 | * Note also that "g" can be the old leader with ->mm == NULL | |
1573 | * and already unhashed and thus removed from ->thread_group. | |
1574 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1575 | * clear the ->next pointer, we will find the new leader via | |
1576 | * next_thread(). | |
1577 | */ | |
7b1c6154 | 1578 | rcu_read_lock(); |
aceecc04 | 1579 | for_each_process(g) { |
5debfa6d ON |
1580 | if (g == tsk->group_leader) |
1581 | continue; | |
15b9f360 ON |
1582 | if (g->flags & PF_KTHREAD) |
1583 | continue; | |
aceecc04 ON |
1584 | p = g; |
1585 | do { | |
1586 | if (p->mm) { | |
15b9f360 | 1587 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1588 | lock_task_sighand(p, &flags); |
8cd9c249 | 1589 | nr += zap_process(p); |
5debfa6d ON |
1590 | unlock_task_sighand(p, &flags); |
1591 | } | |
aceecc04 ON |
1592 | break; |
1593 | } | |
e4901f92 | 1594 | } while_each_thread(g, p); |
aceecc04 | 1595 | } |
7b1c6154 | 1596 | rcu_read_unlock(); |
5debfa6d | 1597 | done: |
c5f1cc8c | 1598 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1599 | return nr; |
1da177e4 LT |
1600 | } |
1601 | ||
9d5b327b | 1602 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1603 | { |
dcf560c5 ON |
1604 | struct task_struct *tsk = current; |
1605 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1606 | struct completion *vfork_done; |
2384f55f | 1607 | int core_waiters; |
1da177e4 | 1608 | |
9d5b327b | 1609 | init_completion(&core_state->startup); |
b564daf8 ON |
1610 | core_state->dumper.task = tsk; |
1611 | core_state->dumper.next = NULL; | |
9d5b327b | 1612 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
2384f55f ON |
1613 | up_write(&mm->mmap_sem); |
1614 | ||
dcf560c5 ON |
1615 | if (unlikely(core_waiters < 0)) |
1616 | goto fail; | |
1617 | ||
1618 | /* | |
1619 | * Make sure nobody is waiting for us to release the VM, | |
1620 | * otherwise we can deadlock when we wait on each other | |
1621 | */ | |
1622 | vfork_done = tsk->vfork_done; | |
1623 | if (vfork_done) { | |
1624 | tsk->vfork_done = NULL; | |
1625 | complete(vfork_done); | |
1626 | } | |
1627 | ||
2384f55f | 1628 | if (core_waiters) |
9d5b327b | 1629 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1630 | fail: |
dcf560c5 | 1631 | return core_waiters; |
1da177e4 LT |
1632 | } |
1633 | ||
a94e2d40 ON |
1634 | static void coredump_finish(struct mm_struct *mm) |
1635 | { | |
1636 | struct core_thread *curr, *next; | |
1637 | struct task_struct *task; | |
1638 | ||
1639 | next = mm->core_state->dumper.next; | |
1640 | while ((curr = next) != NULL) { | |
1641 | next = curr->next; | |
1642 | task = curr->task; | |
1643 | /* | |
1644 | * see exit_mm(), curr->task must not see | |
1645 | * ->task == NULL before we read ->next. | |
1646 | */ | |
1647 | smp_mb(); | |
1648 | curr->task = NULL; | |
1649 | wake_up_process(task); | |
1650 | } | |
1651 | ||
1652 | mm->core_state = NULL; | |
1653 | } | |
1654 | ||
6c5d5238 KH |
1655 | /* |
1656 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1657 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1658 | * these bits are not changed atomically. So get_dumpable can observe the | |
1659 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1660 | * return either old dumpable or new one by paying attention to the order of | |
1661 | * modifying the bits. | |
1662 | * | |
1663 | * dumpable | mm->flags (binary) | |
1664 | * old new | initial interim final | |
1665 | * ---------+----------------------- | |
1666 | * 0 1 | 00 01 01 | |
1667 | * 0 2 | 00 10(*) 11 | |
1668 | * 1 0 | 01 00 00 | |
1669 | * 1 2 | 01 11 11 | |
1670 | * 2 0 | 11 10(*) 00 | |
1671 | * 2 1 | 11 11 01 | |
1672 | * | |
1673 | * (*) get_dumpable regards interim value of 10 as 11. | |
1674 | */ | |
1675 | void set_dumpable(struct mm_struct *mm, int value) | |
1676 | { | |
1677 | switch (value) { | |
1678 | case 0: | |
1679 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1680 | smp_wmb(); | |
1681 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1682 | break; | |
1683 | case 1: | |
1684 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1685 | smp_wmb(); | |
1686 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1687 | break; | |
1688 | case 2: | |
1689 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1690 | smp_wmb(); | |
1691 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1692 | break; | |
1693 | } | |
1694 | } | |
6c5d5238 KH |
1695 | |
1696 | int get_dumpable(struct mm_struct *mm) | |
1697 | { | |
1698 | int ret; | |
1699 | ||
1700 | ret = mm->flags & 0x3; | |
1701 | return (ret >= 2) ? 2 : ret; | |
1702 | } | |
1703 | ||
8cd3ac3a | 1704 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1da177e4 | 1705 | { |
9d5b327b | 1706 | struct core_state core_state; |
1da177e4 LT |
1707 | char corename[CORENAME_MAX_SIZE + 1]; |
1708 | struct mm_struct *mm = current->mm; | |
1709 | struct linux_binfmt * binfmt; | |
1710 | struct inode * inode; | |
1711 | struct file * file; | |
d84f4f99 DH |
1712 | const struct cred *old_cred; |
1713 | struct cred *cred; | |
1da177e4 | 1714 | int retval = 0; |
d6e71144 | 1715 | int flag = 0; |
d025c9db | 1716 | int ispipe = 0; |
7dc0b22e | 1717 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
74aadce9 NH |
1718 | char **helper_argv = NULL; |
1719 | int helper_argc = 0; | |
1720 | char *delimit; | |
1da177e4 | 1721 | |
0a4ff8c2 SG |
1722 | audit_core_dumps(signr); |
1723 | ||
1da177e4 LT |
1724 | binfmt = current->binfmt; |
1725 | if (!binfmt || !binfmt->core_dump) | |
1726 | goto fail; | |
d84f4f99 DH |
1727 | |
1728 | cred = prepare_creds(); | |
1729 | if (!cred) { | |
1730 | retval = -ENOMEM; | |
1731 | goto fail; | |
1732 | } | |
1733 | ||
1da177e4 | 1734 | down_write(&mm->mmap_sem); |
00ec99da RM |
1735 | /* |
1736 | * If another thread got here first, or we are not dumpable, bail out. | |
1737 | */ | |
999d9fc1 | 1738 | if (mm->core_state || !get_dumpable(mm)) { |
1da177e4 | 1739 | up_write(&mm->mmap_sem); |
d84f4f99 | 1740 | put_cred(cred); |
1da177e4 LT |
1741 | goto fail; |
1742 | } | |
d6e71144 AC |
1743 | |
1744 | /* | |
1745 | * We cannot trust fsuid as being the "true" uid of the | |
1746 | * process nor do we know its entire history. We only know it | |
1747 | * was tainted so we dump it as root in mode 2. | |
1748 | */ | |
6c5d5238 | 1749 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 | 1750 | flag = O_EXCL; /* Stop rewrite attacks */ |
d84f4f99 | 1751 | cred->fsuid = 0; /* Dump root private */ |
d6e71144 | 1752 | } |
1291cf41 | 1753 | |
9d5b327b | 1754 | retval = coredump_wait(exit_code, &core_state); |
d84f4f99 DH |
1755 | if (retval < 0) { |
1756 | put_cred(cred); | |
1291cf41 | 1757 | goto fail; |
d84f4f99 DH |
1758 | } |
1759 | ||
1760 | old_cred = override_creds(cred); | |
1da177e4 LT |
1761 | |
1762 | /* | |
1763 | * Clear any false indication of pending signals that might | |
1764 | * be seen by the filesystem code called to write the core file. | |
1765 | */ | |
1da177e4 LT |
1766 | clear_thread_flag(TIF_SIGPENDING); |
1767 | ||
1da177e4 LT |
1768 | /* |
1769 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1770 | * uses lock_kernel() | |
1771 | */ | |
1772 | lock_kernel(); | |
6409324b | 1773 | ispipe = format_corename(corename, signr); |
1da177e4 | 1774 | unlock_kernel(); |
7dc0b22e NH |
1775 | /* |
1776 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1777 | * to a pipe. Since we're not writing directly to the filesystem | |
1778 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1779 | * created unless the pipe reader choses to write out the core file | |
1780 | * at which point file size limits and permissions will be imposed | |
1781 | * as it does with any other process | |
1782 | */ | |
74aadce9 | 1783 | if ((!ispipe) && (core_limit < binfmt->min_coredump)) |
7dc0b22e NH |
1784 | goto fail_unlock; |
1785 | ||
c4bbafda | 1786 | if (ispipe) { |
74aadce9 | 1787 | helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc); |
350eaf79 TH |
1788 | if (!helper_argv) { |
1789 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
1790 | __func__); | |
1791 | goto fail_unlock; | |
1792 | } | |
74aadce9 NH |
1793 | /* Terminate the string before the first option */ |
1794 | delimit = strchr(corename, ' '); | |
1795 | if (delimit) | |
1796 | *delimit = '\0'; | |
32321137 NH |
1797 | delimit = strrchr(helper_argv[0], '/'); |
1798 | if (delimit) | |
1799 | delimit++; | |
1800 | else | |
1801 | delimit = helper_argv[0]; | |
1802 | if (!strcmp(delimit, current->comm)) { | |
1803 | printk(KERN_NOTICE "Recursive core dump detected, " | |
1804 | "aborting\n"); | |
1805 | goto fail_unlock; | |
1806 | } | |
1807 | ||
1808 | core_limit = RLIM_INFINITY; | |
1809 | ||
d025c9db | 1810 | /* SIGPIPE can happen, but it's just never processed */ |
32321137 NH |
1811 | if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, |
1812 | &file)) { | |
d025c9db AK |
1813 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1814 | corename); | |
1815 | goto fail_unlock; | |
1816 | } | |
d025c9db AK |
1817 | } else |
1818 | file = filp_open(corename, | |
6d4df677 AD |
1819 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1820 | 0600); | |
1da177e4 LT |
1821 | if (IS_ERR(file)) |
1822 | goto fail_unlock; | |
0f7fc9e4 | 1823 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1824 | if (inode->i_nlink > 1) |
1825 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1826 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1827 | goto close_fail; |
1828 | ||
d025c9db AK |
1829 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1830 | but keep the previous behaviour for now. */ | |
1831 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 | 1832 | goto close_fail; |
c46f739d IM |
1833 | /* |
1834 | * Dont allow local users get cute and trick others to coredump | |
1835 | * into their pre-created files: | |
1836 | */ | |
da9592ed | 1837 | if (inode->i_uid != current_fsuid()) |
c46f739d | 1838 | goto close_fail; |
1da177e4 LT |
1839 | if (!file->f_op) |
1840 | goto close_fail; | |
1841 | if (!file->f_op->write) | |
1842 | goto close_fail; | |
0f7fc9e4 | 1843 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1844 | goto close_fail; |
1845 | ||
7dc0b22e | 1846 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1847 | |
1848 | if (retval) | |
1849 | current->signal->group_exit_code |= 0x80; | |
1850 | close_fail: | |
1851 | filp_close(file, NULL); | |
1852 | fail_unlock: | |
74aadce9 NH |
1853 | if (helper_argv) |
1854 | argv_free(helper_argv); | |
1855 | ||
d84f4f99 DH |
1856 | revert_creds(old_cred); |
1857 | put_cred(cred); | |
a94e2d40 | 1858 | coredump_finish(mm); |
1da177e4 | 1859 | fail: |
8cd3ac3a | 1860 | return; |
1da177e4 | 1861 | } |