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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> |
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; |
1da177e4 | 108 | struct nameidata nd; |
964bd183 AV |
109 | char *tmp = getname(library); |
110 | int error = PTR_ERR(tmp); | |
111 | ||
112 | if (!IS_ERR(tmp)) { | |
113 | error = path_lookup_open(AT_FDCWD, tmp, | |
114 | LOOKUP_FOLLOW, &nd, | |
115 | FMODE_READ|FMODE_EXEC); | |
116 | putname(tmp); | |
117 | } | |
1da177e4 LT |
118 | if (error) |
119 | goto out; | |
120 | ||
121 | error = -EINVAL; | |
4ac91378 | 122 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) |
1da177e4 LT |
123 | goto exit; |
124 | ||
30524472 AV |
125 | error = -EACCES; |
126 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) | |
127 | goto exit; | |
128 | ||
a44ddbb6 | 129 | error = may_open(&nd.path, MAY_READ | MAY_EXEC | MAY_OPEN, 0); |
1da177e4 LT |
130 | if (error) |
131 | goto exit; | |
132 | ||
abe8be3a | 133 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); |
1da177e4 LT |
134 | error = PTR_ERR(file); |
135 | if (IS_ERR(file)) | |
136 | goto out; | |
137 | ||
6110e3ab EP |
138 | fsnotify_open(file->f_path.dentry); |
139 | ||
1da177e4 LT |
140 | error = -ENOEXEC; |
141 | if(file->f_op) { | |
142 | struct linux_binfmt * fmt; | |
143 | ||
144 | read_lock(&binfmt_lock); | |
e4dc1b14 | 145 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
146 | if (!fmt->load_shlib) |
147 | continue; | |
148 | if (!try_module_get(fmt->module)) | |
149 | continue; | |
150 | read_unlock(&binfmt_lock); | |
151 | error = fmt->load_shlib(file); | |
152 | read_lock(&binfmt_lock); | |
153 | put_binfmt(fmt); | |
154 | if (error != -ENOEXEC) | |
155 | break; | |
156 | } | |
157 | read_unlock(&binfmt_lock); | |
158 | } | |
159 | fput(file); | |
160 | out: | |
161 | return error; | |
162 | exit: | |
834f2a4a | 163 | release_open_intent(&nd); |
1d957f9b | 164 | path_put(&nd.path); |
1da177e4 LT |
165 | goto out; |
166 | } | |
167 | ||
b6a2fea3 OW |
168 | #ifdef CONFIG_MMU |
169 | ||
170 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
171 | int write) | |
172 | { | |
173 | struct page *page; | |
174 | int ret; | |
175 | ||
176 | #ifdef CONFIG_STACK_GROWSUP | |
177 | if (write) { | |
178 | ret = expand_stack_downwards(bprm->vma, pos); | |
179 | if (ret < 0) | |
180 | return NULL; | |
181 | } | |
182 | #endif | |
183 | ret = get_user_pages(current, bprm->mm, pos, | |
184 | 1, write, 1, &page, NULL); | |
185 | if (ret <= 0) | |
186 | return NULL; | |
187 | ||
188 | if (write) { | |
b6a2fea3 | 189 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
190 | struct rlimit *rlim; |
191 | ||
192 | /* | |
193 | * We've historically supported up to 32 pages (ARG_MAX) | |
194 | * of argument strings even with small stacks | |
195 | */ | |
196 | if (size <= ARG_MAX) | |
197 | return page; | |
b6a2fea3 OW |
198 | |
199 | /* | |
200 | * Limit to 1/4-th the stack size for the argv+env strings. | |
201 | * This ensures that: | |
202 | * - the remaining binfmt code will not run out of stack space, | |
203 | * - the program will have a reasonable amount of stack left | |
204 | * to work from. | |
205 | */ | |
a64e715f | 206 | rlim = current->signal->rlim; |
b6a2fea3 OW |
207 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { |
208 | put_page(page); | |
209 | return NULL; | |
210 | } | |
211 | } | |
212 | ||
213 | return page; | |
214 | } | |
215 | ||
216 | static void put_arg_page(struct page *page) | |
217 | { | |
218 | put_page(page); | |
219 | } | |
220 | ||
221 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
222 | { | |
223 | } | |
224 | ||
225 | static void free_arg_pages(struct linux_binprm *bprm) | |
226 | { | |
227 | } | |
228 | ||
229 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
230 | struct page *page) | |
231 | { | |
232 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
233 | } | |
234 | ||
235 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
236 | { | |
eaccbfa5 | 237 | int err; |
b6a2fea3 OW |
238 | struct vm_area_struct *vma = NULL; |
239 | struct mm_struct *mm = bprm->mm; | |
240 | ||
241 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
242 | if (!vma) | |
eaccbfa5 | 243 | return -ENOMEM; |
b6a2fea3 OW |
244 | |
245 | down_write(&mm->mmap_sem); | |
246 | vma->vm_mm = mm; | |
247 | ||
248 | /* | |
249 | * Place the stack at the largest stack address the architecture | |
250 | * supports. Later, we'll move this to an appropriate place. We don't | |
251 | * use STACK_TOP because that can depend on attributes which aren't | |
252 | * configured yet. | |
253 | */ | |
254 | vma->vm_end = STACK_TOP_MAX; | |
255 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
b6a2fea3 | 256 | vma->vm_flags = VM_STACK_FLAGS; |
3ed75eb8 | 257 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
b6a2fea3 | 258 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 259 | if (err) |
b6a2fea3 | 260 | goto err; |
b6a2fea3 OW |
261 | |
262 | mm->stack_vm = mm->total_vm = 1; | |
263 | up_write(&mm->mmap_sem); | |
b6a2fea3 | 264 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 265 | return 0; |
b6a2fea3 | 266 | err: |
eaccbfa5 LFC |
267 | up_write(&mm->mmap_sem); |
268 | bprm->vma = NULL; | |
269 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
270 | return err; |
271 | } | |
272 | ||
273 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
274 | { | |
275 | return len <= MAX_ARG_STRLEN; | |
276 | } | |
277 | ||
278 | #else | |
279 | ||
280 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
281 | int write) | |
282 | { | |
283 | struct page *page; | |
284 | ||
285 | page = bprm->page[pos / PAGE_SIZE]; | |
286 | if (!page && write) { | |
287 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
288 | if (!page) | |
289 | return NULL; | |
290 | bprm->page[pos / PAGE_SIZE] = page; | |
291 | } | |
292 | ||
293 | return page; | |
294 | } | |
295 | ||
296 | static void put_arg_page(struct page *page) | |
297 | { | |
298 | } | |
299 | ||
300 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
301 | { | |
302 | if (bprm->page[i]) { | |
303 | __free_page(bprm->page[i]); | |
304 | bprm->page[i] = NULL; | |
305 | } | |
306 | } | |
307 | ||
308 | static void free_arg_pages(struct linux_binprm *bprm) | |
309 | { | |
310 | int i; | |
311 | ||
312 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
313 | free_arg_page(bprm, i); | |
314 | } | |
315 | ||
316 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
317 | struct page *page) | |
318 | { | |
319 | } | |
320 | ||
321 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
322 | { | |
323 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
324 | return 0; | |
325 | } | |
326 | ||
327 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
328 | { | |
329 | return len <= bprm->p; | |
330 | } | |
331 | ||
332 | #endif /* CONFIG_MMU */ | |
333 | ||
334 | /* | |
335 | * Create a new mm_struct and populate it with a temporary stack | |
336 | * vm_area_struct. We don't have enough context at this point to set the stack | |
337 | * flags, permissions, and offset, so we use temporary values. We'll update | |
338 | * them later in setup_arg_pages(). | |
339 | */ | |
340 | int bprm_mm_init(struct linux_binprm *bprm) | |
341 | { | |
342 | int err; | |
343 | struct mm_struct *mm = NULL; | |
344 | ||
345 | bprm->mm = mm = mm_alloc(); | |
346 | err = -ENOMEM; | |
347 | if (!mm) | |
348 | goto err; | |
349 | ||
350 | err = init_new_context(current, mm); | |
351 | if (err) | |
352 | goto err; | |
353 | ||
354 | err = __bprm_mm_init(bprm); | |
355 | if (err) | |
356 | goto err; | |
357 | ||
358 | return 0; | |
359 | ||
360 | err: | |
361 | if (mm) { | |
362 | bprm->mm = NULL; | |
363 | mmdrop(mm); | |
364 | } | |
365 | ||
366 | return err; | |
367 | } | |
368 | ||
1da177e4 LT |
369 | /* |
370 | * count() counts the number of strings in array ARGV. | |
371 | */ | |
372 | static int count(char __user * __user * argv, int max) | |
373 | { | |
374 | int i = 0; | |
375 | ||
376 | if (argv != NULL) { | |
377 | for (;;) { | |
378 | char __user * p; | |
379 | ||
380 | if (get_user(p, argv)) | |
381 | return -EFAULT; | |
382 | if (!p) | |
383 | break; | |
384 | argv++; | |
362e6663 | 385 | if (i++ >= max) |
1da177e4 LT |
386 | return -E2BIG; |
387 | cond_resched(); | |
388 | } | |
389 | } | |
390 | return i; | |
391 | } | |
392 | ||
393 | /* | |
b6a2fea3 OW |
394 | * 'copy_strings()' copies argument/environment strings from the old |
395 | * processes's memory to the new process's stack. The call to get_user_pages() | |
396 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 397 | */ |
75c96f85 AB |
398 | static int copy_strings(int argc, char __user * __user * argv, |
399 | struct linux_binprm *bprm) | |
1da177e4 LT |
400 | { |
401 | struct page *kmapped_page = NULL; | |
402 | char *kaddr = NULL; | |
b6a2fea3 | 403 | unsigned long kpos = 0; |
1da177e4 LT |
404 | int ret; |
405 | ||
406 | while (argc-- > 0) { | |
407 | char __user *str; | |
408 | int len; | |
409 | unsigned long pos; | |
410 | ||
411 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 412 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
413 | ret = -EFAULT; |
414 | goto out; | |
415 | } | |
416 | ||
b6a2fea3 | 417 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
418 | ret = -E2BIG; |
419 | goto out; | |
420 | } | |
421 | ||
b6a2fea3 | 422 | /* We're going to work our way backwords. */ |
1da177e4 | 423 | pos = bprm->p; |
b6a2fea3 OW |
424 | str += len; |
425 | bprm->p -= len; | |
1da177e4 LT |
426 | |
427 | while (len > 0) { | |
1da177e4 | 428 | int offset, bytes_to_copy; |
1da177e4 LT |
429 | |
430 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
431 | if (offset == 0) |
432 | offset = PAGE_SIZE; | |
433 | ||
434 | bytes_to_copy = offset; | |
435 | if (bytes_to_copy > len) | |
436 | bytes_to_copy = len; | |
437 | ||
438 | offset -= bytes_to_copy; | |
439 | pos -= bytes_to_copy; | |
440 | str -= bytes_to_copy; | |
441 | len -= bytes_to_copy; | |
442 | ||
443 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
444 | struct page *page; | |
445 | ||
446 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 447 | if (!page) { |
b6a2fea3 | 448 | ret = -E2BIG; |
1da177e4 LT |
449 | goto out; |
450 | } | |
1da177e4 | 451 | |
b6a2fea3 OW |
452 | if (kmapped_page) { |
453 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 454 | kunmap(kmapped_page); |
b6a2fea3 OW |
455 | put_arg_page(kmapped_page); |
456 | } | |
1da177e4 LT |
457 | kmapped_page = page; |
458 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
459 | kpos = pos & PAGE_MASK; |
460 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 461 | } |
b6a2fea3 | 462 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
463 | ret = -EFAULT; |
464 | goto out; | |
465 | } | |
1da177e4 LT |
466 | } |
467 | } | |
468 | ret = 0; | |
469 | out: | |
b6a2fea3 OW |
470 | if (kmapped_page) { |
471 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 472 | kunmap(kmapped_page); |
b6a2fea3 OW |
473 | put_arg_page(kmapped_page); |
474 | } | |
1da177e4 LT |
475 | return ret; |
476 | } | |
477 | ||
478 | /* | |
479 | * Like copy_strings, but get argv and its values from kernel memory. | |
480 | */ | |
481 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
482 | { | |
483 | int r; | |
484 | mm_segment_t oldfs = get_fs(); | |
485 | set_fs(KERNEL_DS); | |
486 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
487 | set_fs(oldfs); | |
488 | return r; | |
489 | } | |
1da177e4 LT |
490 | EXPORT_SYMBOL(copy_strings_kernel); |
491 | ||
492 | #ifdef CONFIG_MMU | |
b6a2fea3 | 493 | |
1da177e4 | 494 | /* |
b6a2fea3 OW |
495 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
496 | * the binfmt code determines where the new stack should reside, we shift it to | |
497 | * its final location. The process proceeds as follows: | |
1da177e4 | 498 | * |
b6a2fea3 OW |
499 | * 1) Use shift to calculate the new vma endpoints. |
500 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
501 | * arguments passed to subsequent functions are consistent. | |
502 | * 3) Move vma's page tables to the new range. | |
503 | * 4) Free up any cleared pgd range. | |
504 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 505 | */ |
b6a2fea3 | 506 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
507 | { |
508 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
509 | unsigned long old_start = vma->vm_start; |
510 | unsigned long old_end = vma->vm_end; | |
511 | unsigned long length = old_end - old_start; | |
512 | unsigned long new_start = old_start - shift; | |
513 | unsigned long new_end = old_end - shift; | |
514 | struct mmu_gather *tlb; | |
1da177e4 | 515 | |
b6a2fea3 | 516 | BUG_ON(new_start > new_end); |
1da177e4 | 517 | |
b6a2fea3 OW |
518 | /* |
519 | * ensure there are no vmas between where we want to go | |
520 | * and where we are | |
521 | */ | |
522 | if (vma != find_vma(mm, new_start)) | |
523 | return -EFAULT; | |
524 | ||
525 | /* | |
526 | * cover the whole range: [new_start, old_end) | |
527 | */ | |
528 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
529 | ||
530 | /* | |
531 | * move the page tables downwards, on failure we rely on | |
532 | * process cleanup to remove whatever mess we made. | |
533 | */ | |
534 | if (length != move_page_tables(vma, old_start, | |
535 | vma, new_start, length)) | |
536 | return -ENOMEM; | |
537 | ||
538 | lru_add_drain(); | |
539 | tlb = tlb_gather_mmu(mm, 0); | |
540 | if (new_end > old_start) { | |
541 | /* | |
542 | * when the old and new regions overlap clear from new_end. | |
543 | */ | |
42b77728 | 544 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
545 | vma->vm_next ? vma->vm_next->vm_start : 0); |
546 | } else { | |
547 | /* | |
548 | * otherwise, clean from old_start; this is done to not touch | |
549 | * the address space in [new_end, old_start) some architectures | |
550 | * have constraints on va-space that make this illegal (IA64) - | |
551 | * for the others its just a little faster. | |
552 | */ | |
42b77728 | 553 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 554 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 555 | } |
b6a2fea3 OW |
556 | tlb_finish_mmu(tlb, new_end, old_end); |
557 | ||
558 | /* | |
559 | * shrink the vma to just the new range. | |
560 | */ | |
561 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
562 | ||
563 | return 0; | |
1da177e4 LT |
564 | } |
565 | ||
566 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
567 | ||
b6a2fea3 OW |
568 | /* |
569 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
570 | * the stack is optionally relocated, and some extra space is added. | |
571 | */ | |
1da177e4 LT |
572 | int setup_arg_pages(struct linux_binprm *bprm, |
573 | unsigned long stack_top, | |
574 | int executable_stack) | |
575 | { | |
b6a2fea3 OW |
576 | unsigned long ret; |
577 | unsigned long stack_shift; | |
1da177e4 | 578 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
579 | struct vm_area_struct *vma = bprm->vma; |
580 | struct vm_area_struct *prev = NULL; | |
581 | unsigned long vm_flags; | |
582 | unsigned long stack_base; | |
1da177e4 LT |
583 | |
584 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
585 | /* Limit stack size to 1GB */ |
586 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
587 | if (stack_base > (1 << 30)) | |
588 | stack_base = 1 << 30; | |
1da177e4 | 589 | |
b6a2fea3 OW |
590 | /* Make sure we didn't let the argument array grow too large. */ |
591 | if (vma->vm_end - vma->vm_start > stack_base) | |
592 | return -ENOMEM; | |
1da177e4 | 593 | |
b6a2fea3 | 594 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 595 | |
b6a2fea3 OW |
596 | stack_shift = vma->vm_start - stack_base; |
597 | mm->arg_start = bprm->p - stack_shift; | |
598 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 599 | #else |
b6a2fea3 OW |
600 | stack_top = arch_align_stack(stack_top); |
601 | stack_top = PAGE_ALIGN(stack_top); | |
602 | stack_shift = vma->vm_end - stack_top; | |
603 | ||
604 | bprm->p -= stack_shift; | |
1da177e4 | 605 | mm->arg_start = bprm->p; |
1da177e4 LT |
606 | #endif |
607 | ||
1da177e4 | 608 | if (bprm->loader) |
b6a2fea3 OW |
609 | bprm->loader -= stack_shift; |
610 | bprm->exec -= stack_shift; | |
1da177e4 | 611 | |
1da177e4 | 612 | down_write(&mm->mmap_sem); |
96a8e13e | 613 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
614 | |
615 | /* | |
616 | * Adjust stack execute permissions; explicitly enable for | |
617 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
618 | * (arch default) otherwise. | |
619 | */ | |
620 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
621 | vm_flags |= VM_EXEC; | |
622 | else if (executable_stack == EXSTACK_DISABLE_X) | |
623 | vm_flags &= ~VM_EXEC; | |
624 | vm_flags |= mm->def_flags; | |
625 | ||
626 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
627 | vm_flags); | |
628 | if (ret) | |
629 | goto out_unlock; | |
630 | BUG_ON(prev != vma); | |
631 | ||
632 | /* Move stack pages down in memory. */ | |
633 | if (stack_shift) { | |
634 | ret = shift_arg_pages(vma, stack_shift); | |
635 | if (ret) { | |
1da177e4 | 636 | up_write(&mm->mmap_sem); |
1da177e4 LT |
637 | return ret; |
638 | } | |
1da177e4 LT |
639 | } |
640 | ||
b6a2fea3 OW |
641 | #ifdef CONFIG_STACK_GROWSUP |
642 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
643 | #else | |
644 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
645 | #endif | |
646 | ret = expand_stack(vma, stack_base); | |
647 | if (ret) | |
648 | ret = -EFAULT; | |
649 | ||
650 | out_unlock: | |
1da177e4 | 651 | up_write(&mm->mmap_sem); |
1da177e4 LT |
652 | return 0; |
653 | } | |
1da177e4 LT |
654 | EXPORT_SYMBOL(setup_arg_pages); |
655 | ||
1da177e4 LT |
656 | #endif /* CONFIG_MMU */ |
657 | ||
658 | struct file *open_exec(const char *name) | |
659 | { | |
660 | struct nameidata nd; | |
1da177e4 | 661 | struct file *file; |
e56b6a5d | 662 | int err; |
1da177e4 | 663 | |
e56b6a5d CH |
664 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, |
665 | FMODE_READ|FMODE_EXEC); | |
666 | if (err) | |
667 | goto out; | |
668 | ||
669 | err = -EACCES; | |
670 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) | |
671 | goto out_path_put; | |
672 | ||
30524472 AV |
673 | if (nd.path.mnt->mnt_flags & MNT_NOEXEC) |
674 | goto out_path_put; | |
675 | ||
a44ddbb6 | 676 | err = may_open(&nd.path, MAY_EXEC | MAY_OPEN, 0); |
e56b6a5d CH |
677 | if (err) |
678 | goto out_path_put; | |
679 | ||
680 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); | |
681 | if (IS_ERR(file)) | |
682 | return file; | |
683 | ||
6110e3ab EP |
684 | fsnotify_open(file->f_path.dentry); |
685 | ||
e56b6a5d CH |
686 | err = deny_write_access(file); |
687 | if (err) { | |
688 | fput(file); | |
689 | goto out; | |
1da177e4 | 690 | } |
1da177e4 | 691 | |
e56b6a5d CH |
692 | return file; |
693 | ||
694 | out_path_put: | |
695 | release_open_intent(&nd); | |
696 | path_put(&nd.path); | |
697 | out: | |
698 | return ERR_PTR(err); | |
699 | } | |
1da177e4 LT |
700 | EXPORT_SYMBOL(open_exec); |
701 | ||
702 | int kernel_read(struct file *file, unsigned long offset, | |
703 | char *addr, unsigned long count) | |
704 | { | |
705 | mm_segment_t old_fs; | |
706 | loff_t pos = offset; | |
707 | int result; | |
708 | ||
709 | old_fs = get_fs(); | |
710 | set_fs(get_ds()); | |
711 | /* The cast to a user pointer is valid due to the set_fs() */ | |
712 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
713 | set_fs(old_fs); | |
714 | return result; | |
715 | } | |
716 | ||
717 | EXPORT_SYMBOL(kernel_read); | |
718 | ||
719 | static int exec_mmap(struct mm_struct *mm) | |
720 | { | |
721 | struct task_struct *tsk; | |
722 | struct mm_struct * old_mm, *active_mm; | |
723 | ||
724 | /* Notify parent that we're no longer interested in the old VM */ | |
725 | tsk = current; | |
726 | old_mm = current->mm; | |
727 | mm_release(tsk, old_mm); | |
728 | ||
729 | if (old_mm) { | |
730 | /* | |
731 | * Make sure that if there is a core dump in progress | |
732 | * for the old mm, we get out and die instead of going | |
733 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 734 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
735 | */ |
736 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 737 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
738 | up_read(&old_mm->mmap_sem); |
739 | return -EINTR; | |
740 | } | |
741 | } | |
742 | task_lock(tsk); | |
743 | active_mm = tsk->active_mm; | |
744 | tsk->mm = mm; | |
745 | tsk->active_mm = mm; | |
746 | activate_mm(active_mm, mm); | |
747 | task_unlock(tsk); | |
748 | arch_pick_mmap_layout(mm); | |
749 | if (old_mm) { | |
750 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 751 | BUG_ON(active_mm != old_mm); |
31a78f23 | 752 | mm_update_next_owner(old_mm); |
1da177e4 LT |
753 | mmput(old_mm); |
754 | return 0; | |
755 | } | |
756 | mmdrop(active_mm); | |
757 | return 0; | |
758 | } | |
759 | ||
760 | /* | |
761 | * This function makes sure the current process has its own signal table, | |
762 | * so that flush_signal_handlers can later reset the handlers without | |
763 | * disturbing other processes. (Other processes might share the signal | |
764 | * table via the CLONE_SIGHAND option to clone().) | |
765 | */ | |
858119e1 | 766 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
767 | { |
768 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 769 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 LT |
770 | spinlock_t *lock = &oldsighand->siglock; |
771 | int count; | |
772 | ||
aafe6c2a | 773 | if (thread_group_empty(tsk)) |
1da177e4 LT |
774 | goto no_thread_group; |
775 | ||
776 | /* | |
777 | * Kill all other threads in the thread group. | |
1da177e4 | 778 | */ |
1da177e4 | 779 | spin_lock_irq(lock); |
ed5d2cac | 780 | if (signal_group_exit(sig)) { |
1da177e4 LT |
781 | /* |
782 | * Another group action in progress, just | |
783 | * return so that the signal is processed. | |
784 | */ | |
785 | spin_unlock_irq(lock); | |
1da177e4 LT |
786 | return -EAGAIN; |
787 | } | |
ed5d2cac | 788 | sig->group_exit_task = tsk; |
aafe6c2a | 789 | zap_other_threads(tsk); |
1da177e4 | 790 | |
fea9d175 ON |
791 | /* Account for the thread group leader hanging around: */ |
792 | count = thread_group_leader(tsk) ? 1 : 2; | |
6db840fa | 793 | sig->notify_count = count; |
1da177e4 | 794 | while (atomic_read(&sig->count) > count) { |
1da177e4 LT |
795 | __set_current_state(TASK_UNINTERRUPTIBLE); |
796 | spin_unlock_irq(lock); | |
797 | schedule(); | |
798 | spin_lock_irq(lock); | |
799 | } | |
1da177e4 LT |
800 | spin_unlock_irq(lock); |
801 | ||
802 | /* | |
803 | * At this point all other threads have exited, all we have to | |
804 | * do is to wait for the thread group leader to become inactive, | |
805 | * and to assume its PID: | |
806 | */ | |
aafe6c2a | 807 | if (!thread_group_leader(tsk)) { |
8187926b | 808 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 809 | |
2800d8d1 | 810 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
811 | for (;;) { |
812 | write_lock_irq(&tasklist_lock); | |
813 | if (likely(leader->exit_state)) | |
814 | break; | |
815 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
816 | write_unlock_irq(&tasklist_lock); | |
817 | schedule(); | |
818 | } | |
1da177e4 | 819 | |
f5e90281 RM |
820 | /* |
821 | * The only record we have of the real-time age of a | |
822 | * process, regardless of execs it's done, is start_time. | |
823 | * All the past CPU time is accumulated in signal_struct | |
824 | * from sister threads now dead. But in this non-leader | |
825 | * exec, nothing survives from the original leader thread, | |
826 | * whose birth marks the true age of this process now. | |
827 | * When we take on its identity by switching to its PID, we | |
828 | * also take its birthdate (always earlier than our own). | |
829 | */ | |
aafe6c2a | 830 | tsk->start_time = leader->start_time; |
f5e90281 | 831 | |
bac0abd6 PE |
832 | BUG_ON(!same_thread_group(leader, tsk)); |
833 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
834 | /* |
835 | * An exec() starts a new thread group with the | |
836 | * TGID of the previous thread group. Rehash the | |
837 | * two threads with a switched PID, and release | |
838 | * the former thread group leader: | |
839 | */ | |
d73d6529 EB |
840 | |
841 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
842 | * The old leader becomes a thread of the this thread group. |
843 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
844 | * is called. Odd but simple and correct. |
845 | */ | |
aafe6c2a EB |
846 | detach_pid(tsk, PIDTYPE_PID); |
847 | tsk->pid = leader->pid; | |
3743ca05 | 848 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
849 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
850 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
851 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 852 | |
aafe6c2a EB |
853 | tsk->group_leader = tsk; |
854 | leader->group_leader = tsk; | |
de12a787 | 855 | |
aafe6c2a | 856 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
857 | |
858 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
859 | leader->exit_state = EXIT_DEAD; | |
1da177e4 | 860 | write_unlock_irq(&tasklist_lock); |
8187926b ON |
861 | |
862 | release_task(leader); | |
ed5d2cac | 863 | } |
1da177e4 | 864 | |
6db840fa ON |
865 | sig->group_exit_task = NULL; |
866 | sig->notify_count = 0; | |
1da177e4 LT |
867 | |
868 | no_thread_group: | |
1da177e4 | 869 | exit_itimers(sig); |
cbaffba1 | 870 | flush_itimer_signals(); |
329f7dba | 871 | |
b2c903b8 ON |
872 | if (atomic_read(&oldsighand->count) != 1) { |
873 | struct sighand_struct *newsighand; | |
1da177e4 | 874 | /* |
b2c903b8 ON |
875 | * This ->sighand is shared with the CLONE_SIGHAND |
876 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 877 | */ |
b2c903b8 ON |
878 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
879 | if (!newsighand) | |
880 | return -ENOMEM; | |
881 | ||
1da177e4 LT |
882 | atomic_set(&newsighand->count, 1); |
883 | memcpy(newsighand->action, oldsighand->action, | |
884 | sizeof(newsighand->action)); | |
885 | ||
886 | write_lock_irq(&tasklist_lock); | |
887 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 888 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
889 | spin_unlock(&oldsighand->siglock); |
890 | write_unlock_irq(&tasklist_lock); | |
891 | ||
fba2afaa | 892 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
893 | } |
894 | ||
aafe6c2a | 895 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
896 | return 0; |
897 | } | |
0840a90d | 898 | |
1da177e4 LT |
899 | /* |
900 | * These functions flushes out all traces of the currently running executable | |
901 | * so that a new one can be started | |
902 | */ | |
858119e1 | 903 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
904 | { |
905 | long j = -1; | |
badf1662 | 906 | struct fdtable *fdt; |
1da177e4 LT |
907 | |
908 | spin_lock(&files->file_lock); | |
909 | for (;;) { | |
910 | unsigned long set, i; | |
911 | ||
912 | j++; | |
913 | i = j * __NFDBITS; | |
badf1662 | 914 | fdt = files_fdtable(files); |
bbea9f69 | 915 | if (i >= fdt->max_fds) |
1da177e4 | 916 | break; |
badf1662 | 917 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
918 | if (!set) |
919 | continue; | |
badf1662 | 920 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
921 | spin_unlock(&files->file_lock); |
922 | for ( ; set ; i++,set >>= 1) { | |
923 | if (set & 1) { | |
924 | sys_close(i); | |
925 | } | |
926 | } | |
927 | spin_lock(&files->file_lock); | |
928 | ||
929 | } | |
930 | spin_unlock(&files->file_lock); | |
931 | } | |
932 | ||
59714d65 | 933 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
934 | { |
935 | /* buf must be at least sizeof(tsk->comm) in size */ | |
936 | task_lock(tsk); | |
937 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
938 | task_unlock(tsk); | |
59714d65 | 939 | return buf; |
1da177e4 LT |
940 | } |
941 | ||
942 | void set_task_comm(struct task_struct *tsk, char *buf) | |
943 | { | |
944 | task_lock(tsk); | |
945 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
946 | task_unlock(tsk); | |
947 | } | |
948 | ||
949 | int flush_old_exec(struct linux_binprm * bprm) | |
950 | { | |
951 | char * name; | |
952 | int i, ch, retval; | |
1da177e4 LT |
953 | char tcomm[sizeof(current->comm)]; |
954 | ||
955 | /* | |
956 | * Make sure we have a private signal table and that | |
957 | * we are unassociated from the previous thread group. | |
958 | */ | |
959 | retval = de_thread(current); | |
960 | if (retval) | |
961 | goto out; | |
962 | ||
925d1c40 MH |
963 | set_mm_exe_file(bprm->mm, bprm->file); |
964 | ||
1da177e4 LT |
965 | /* |
966 | * Release all of the old mmap stuff | |
967 | */ | |
968 | retval = exec_mmap(bprm->mm); | |
969 | if (retval) | |
fd8328be | 970 | goto out; |
1da177e4 LT |
971 | |
972 | bprm->mm = NULL; /* We're using it now */ | |
973 | ||
974 | /* This is the point of no return */ | |
1da177e4 LT |
975 | current->sas_ss_sp = current->sas_ss_size = 0; |
976 | ||
da9592ed | 977 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
6c5d5238 | 978 | set_dumpable(current->mm, 1); |
d6e71144 | 979 | else |
6c5d5238 | 980 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 981 | |
1da177e4 | 982 | name = bprm->filename; |
36772092 PBG |
983 | |
984 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
985 | for (i=0; (ch = *(name++)) != '\0';) { |
986 | if (ch == '/') | |
36772092 | 987 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
988 | else |
989 | if (i < (sizeof(tcomm) - 1)) | |
990 | tcomm[i++] = ch; | |
991 | } | |
992 | tcomm[i] = '\0'; | |
993 | set_task_comm(current, tcomm); | |
994 | ||
995 | current->flags &= ~PF_RANDOMIZE; | |
996 | flush_thread(); | |
997 | ||
0551fbd2 BH |
998 | /* Set the new mm task size. We have to do that late because it may |
999 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1000 | * some architectures like powerpc | |
1001 | */ | |
1002 | current->mm->task_size = TASK_SIZE; | |
1003 | ||
a6f76f23 DH |
1004 | /* install the new credentials */ |
1005 | if (bprm->cred->uid != current_euid() || | |
1006 | bprm->cred->gid != current_egid()) { | |
d2d56c5f MH |
1007 | current->pdeath_signal = 0; |
1008 | } else if (file_permission(bprm->file, MAY_READ) || | |
a6f76f23 | 1009 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
6c5d5238 | 1010 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1011 | } |
1012 | ||
a6f76f23 DH |
1013 | current->personality &= ~bprm->per_clear; |
1014 | ||
1da177e4 LT |
1015 | /* An exec changes our domain. We are no longer part of the thread |
1016 | group */ | |
1017 | ||
1018 | current->self_exec_id++; | |
1019 | ||
1020 | flush_signal_handlers(current, 0); | |
1021 | flush_old_files(current->files); | |
1022 | ||
1023 | return 0; | |
1024 | ||
1da177e4 LT |
1025 | out: |
1026 | return retval; | |
1027 | } | |
1028 | ||
1029 | EXPORT_SYMBOL(flush_old_exec); | |
1030 | ||
a6f76f23 DH |
1031 | /* |
1032 | * install the new credentials for this executable | |
1033 | */ | |
1034 | void install_exec_creds(struct linux_binprm *bprm) | |
1035 | { | |
1036 | security_bprm_committing_creds(bprm); | |
1037 | ||
1038 | commit_creds(bprm->cred); | |
1039 | bprm->cred = NULL; | |
1040 | ||
1041 | /* cred_exec_mutex must be held at least to this point to prevent | |
1042 | * ptrace_attach() from altering our determination of the task's | |
1043 | * credentials; any time after this it may be unlocked */ | |
1044 | ||
1045 | security_bprm_committed_creds(bprm); | |
1046 | } | |
1047 | EXPORT_SYMBOL(install_exec_creds); | |
1048 | ||
1049 | /* | |
1050 | * determine how safe it is to execute the proposed program | |
1051 | * - the caller must hold current->cred_exec_mutex to protect against | |
1052 | * PTRACE_ATTACH | |
1053 | */ | |
498052bb | 1054 | int check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1055 | { |
0bf2f3ae | 1056 | struct task_struct *p = current, *t; |
f1191b50 | 1057 | unsigned n_fs; |
498052bb | 1058 | int res = 0; |
a6f76f23 DH |
1059 | |
1060 | bprm->unsafe = tracehook_unsafe_exec(p); | |
1061 | ||
0bf2f3ae | 1062 | n_fs = 1; |
498052bb | 1063 | write_lock(&p->fs->lock); |
437f7fdb | 1064 | rcu_read_lock(); |
0bf2f3ae DH |
1065 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
1066 | if (t->fs == p->fs) | |
1067 | n_fs++; | |
0bf2f3ae | 1068 | } |
437f7fdb | 1069 | rcu_read_unlock(); |
0bf2f3ae | 1070 | |
f1191b50 | 1071 | if (p->fs->users > n_fs) { |
a6f76f23 | 1072 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
498052bb | 1073 | } else { |
8c652f96 ON |
1074 | res = -EAGAIN; |
1075 | if (!p->fs->in_exec) { | |
1076 | p->fs->in_exec = 1; | |
1077 | res = 1; | |
1078 | } | |
498052bb | 1079 | } |
498052bb AV |
1080 | write_unlock(&p->fs->lock); |
1081 | ||
1082 | return res; | |
a6f76f23 DH |
1083 | } |
1084 | ||
1da177e4 LT |
1085 | /* |
1086 | * Fill the binprm structure from the inode. | |
1087 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
a6f76f23 DH |
1088 | * |
1089 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1090 | */ |
1091 | int prepare_binprm(struct linux_binprm *bprm) | |
1092 | { | |
a6f76f23 | 1093 | umode_t mode; |
0f7fc9e4 | 1094 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1095 | int retval; |
1096 | ||
1097 | mode = inode->i_mode; | |
1da177e4 LT |
1098 | if (bprm->file->f_op == NULL) |
1099 | return -EACCES; | |
1100 | ||
a6f76f23 DH |
1101 | /* clear any previous set[ug]id data from a previous binary */ |
1102 | bprm->cred->euid = current_euid(); | |
1103 | bprm->cred->egid = current_egid(); | |
1da177e4 | 1104 | |
a6f76f23 | 1105 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1106 | /* Set-uid? */ |
1107 | if (mode & S_ISUID) { | |
a6f76f23 DH |
1108 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1109 | bprm->cred->euid = inode->i_uid; | |
1da177e4 LT |
1110 | } |
1111 | ||
1112 | /* Set-gid? */ | |
1113 | /* | |
1114 | * If setgid is set but no group execute bit then this | |
1115 | * is a candidate for mandatory locking, not a setgid | |
1116 | * executable. | |
1117 | */ | |
1118 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
a6f76f23 DH |
1119 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1120 | bprm->cred->egid = inode->i_gid; | |
1da177e4 LT |
1121 | } |
1122 | } | |
1123 | ||
1124 | /* fill in binprm security blob */ | |
a6f76f23 | 1125 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1126 | if (retval) |
1127 | return retval; | |
a6f76f23 | 1128 | bprm->cred_prepared = 1; |
1da177e4 | 1129 | |
a6f76f23 DH |
1130 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1131 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1132 | } |
1133 | ||
1134 | EXPORT_SYMBOL(prepare_binprm); | |
1135 | ||
4fc75ff4 NP |
1136 | /* |
1137 | * Arguments are '\0' separated strings found at the location bprm->p | |
1138 | * points to; chop off the first by relocating brpm->p to right after | |
1139 | * the first '\0' encountered. | |
1140 | */ | |
b6a2fea3 | 1141 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1142 | { |
b6a2fea3 OW |
1143 | int ret = 0; |
1144 | unsigned long offset; | |
1145 | char *kaddr; | |
1146 | struct page *page; | |
4fc75ff4 | 1147 | |
b6a2fea3 OW |
1148 | if (!bprm->argc) |
1149 | return 0; | |
1da177e4 | 1150 | |
b6a2fea3 OW |
1151 | do { |
1152 | offset = bprm->p & ~PAGE_MASK; | |
1153 | page = get_arg_page(bprm, bprm->p, 0); | |
1154 | if (!page) { | |
1155 | ret = -EFAULT; | |
1156 | goto out; | |
1157 | } | |
1158 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1159 | |
b6a2fea3 OW |
1160 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1161 | offset++, bprm->p++) | |
1162 | ; | |
4fc75ff4 | 1163 | |
b6a2fea3 OW |
1164 | kunmap_atomic(kaddr, KM_USER0); |
1165 | put_arg_page(page); | |
4fc75ff4 | 1166 | |
b6a2fea3 OW |
1167 | if (offset == PAGE_SIZE) |
1168 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1169 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1170 | |
b6a2fea3 OW |
1171 | bprm->p++; |
1172 | bprm->argc--; | |
1173 | ret = 0; | |
4fc75ff4 | 1174 | |
b6a2fea3 OW |
1175 | out: |
1176 | return ret; | |
1da177e4 | 1177 | } |
1da177e4 LT |
1178 | EXPORT_SYMBOL(remove_arg_zero); |
1179 | ||
1180 | /* | |
1181 | * cycle the list of binary formats handler, until one recognizes the image | |
1182 | */ | |
1183 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1184 | { | |
85f33466 | 1185 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1186 | int try,retval; |
1187 | struct linux_binfmt *fmt; | |
1da177e4 | 1188 | |
1da177e4 | 1189 | retval = security_bprm_check(bprm); |
6146f0d5 MZ |
1190 | if (retval) |
1191 | return retval; | |
1192 | retval = ima_bprm_check(bprm); | |
1da177e4 LT |
1193 | if (retval) |
1194 | return retval; | |
1195 | ||
1196 | /* kernel module loader fixup */ | |
1197 | /* so we don't try to load run modprobe in kernel space. */ | |
1198 | set_fs(USER_DS); | |
473ae30b AV |
1199 | |
1200 | retval = audit_bprm(bprm); | |
1201 | if (retval) | |
1202 | return retval; | |
1203 | ||
1da177e4 LT |
1204 | retval = -ENOENT; |
1205 | for (try=0; try<2; try++) { | |
1206 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1207 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1208 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1209 | if (!fn) | |
1210 | continue; | |
1211 | if (!try_module_get(fmt->module)) | |
1212 | continue; | |
1213 | read_unlock(&binfmt_lock); | |
1214 | retval = fn(bprm, regs); | |
85f33466 RM |
1215 | /* |
1216 | * Restore the depth counter to its starting value | |
1217 | * in this call, so we don't have to rely on every | |
1218 | * load_binary function to restore it on return. | |
1219 | */ | |
1220 | bprm->recursion_depth = depth; | |
1da177e4 | 1221 | if (retval >= 0) { |
85f33466 RM |
1222 | if (depth == 0) |
1223 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1224 | put_binfmt(fmt); |
1225 | allow_write_access(bprm->file); | |
1226 | if (bprm->file) | |
1227 | fput(bprm->file); | |
1228 | bprm->file = NULL; | |
1229 | current->did_exec = 1; | |
9f46080c | 1230 | proc_exec_connector(current); |
1da177e4 LT |
1231 | return retval; |
1232 | } | |
1233 | read_lock(&binfmt_lock); | |
1234 | put_binfmt(fmt); | |
1235 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1236 | break; | |
1237 | if (!bprm->file) { | |
1238 | read_unlock(&binfmt_lock); | |
1239 | return retval; | |
1240 | } | |
1241 | } | |
1242 | read_unlock(&binfmt_lock); | |
1243 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1244 | break; | |
5f4123be JB |
1245 | #ifdef CONFIG_MODULES |
1246 | } else { | |
1da177e4 LT |
1247 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1248 | if (printable(bprm->buf[0]) && | |
1249 | printable(bprm->buf[1]) && | |
1250 | printable(bprm->buf[2]) && | |
1251 | printable(bprm->buf[3])) | |
1252 | break; /* -ENOEXEC */ | |
1253 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1254 | #endif | |
1255 | } | |
1256 | } | |
1257 | return retval; | |
1258 | } | |
1259 | ||
1260 | EXPORT_SYMBOL(search_binary_handler); | |
1261 | ||
08a6fac1 AV |
1262 | void free_bprm(struct linux_binprm *bprm) |
1263 | { | |
1264 | free_arg_pages(bprm); | |
a6f76f23 DH |
1265 | if (bprm->cred) |
1266 | abort_creds(bprm->cred); | |
08a6fac1 AV |
1267 | kfree(bprm); |
1268 | } | |
1269 | ||
1da177e4 LT |
1270 | /* |
1271 | * sys_execve() executes a new program. | |
1272 | */ | |
1273 | int do_execve(char * filename, | |
1274 | char __user *__user *argv, | |
1275 | char __user *__user *envp, | |
1276 | struct pt_regs * regs) | |
1277 | { | |
1278 | struct linux_binprm *bprm; | |
1279 | struct file *file; | |
3b125388 | 1280 | struct files_struct *displaced; |
8c652f96 | 1281 | bool clear_in_exec; |
1da177e4 | 1282 | int retval; |
1da177e4 | 1283 | |
3b125388 | 1284 | retval = unshare_files(&displaced); |
fd8328be AV |
1285 | if (retval) |
1286 | goto out_ret; | |
1287 | ||
1da177e4 | 1288 | retval = -ENOMEM; |
11b0b5ab | 1289 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1290 | if (!bprm) |
fd8328be | 1291 | goto out_files; |
1da177e4 | 1292 | |
a6f76f23 DH |
1293 | retval = mutex_lock_interruptible(¤t->cred_exec_mutex); |
1294 | if (retval < 0) | |
1295 | goto out_free; | |
f9ce1f1c | 1296 | current->in_execve = 1; |
a6f76f23 DH |
1297 | |
1298 | retval = -ENOMEM; | |
1299 | bprm->cred = prepare_exec_creds(); | |
1300 | if (!bprm->cred) | |
1301 | goto out_unlock; | |
498052bb AV |
1302 | |
1303 | retval = check_unsafe_exec(bprm); | |
8c652f96 | 1304 | if (retval < 0) |
498052bb | 1305 | goto out_unlock; |
8c652f96 | 1306 | clear_in_exec = retval; |
a6f76f23 | 1307 | |
1da177e4 LT |
1308 | file = open_exec(filename); |
1309 | retval = PTR_ERR(file); | |
1310 | if (IS_ERR(file)) | |
498052bb | 1311 | goto out_unmark; |
1da177e4 LT |
1312 | |
1313 | sched_exec(); | |
1314 | ||
1da177e4 LT |
1315 | bprm->file = file; |
1316 | bprm->filename = filename; | |
1317 | bprm->interp = filename; | |
1da177e4 | 1318 | |
b6a2fea3 OW |
1319 | retval = bprm_mm_init(bprm); |
1320 | if (retval) | |
1321 | goto out_file; | |
1da177e4 | 1322 | |
b6a2fea3 | 1323 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1324 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1325 | goto out; |
1da177e4 | 1326 | |
b6a2fea3 | 1327 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1328 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1329 | goto out; |
1330 | ||
1331 | retval = prepare_binprm(bprm); | |
1332 | if (retval < 0) | |
1333 | goto out; | |
1334 | ||
1335 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1336 | if (retval < 0) | |
1337 | goto out; | |
1338 | ||
1339 | bprm->exec = bprm->p; | |
1340 | retval = copy_strings(bprm->envc, envp, bprm); | |
1341 | if (retval < 0) | |
1342 | goto out; | |
1343 | ||
1344 | retval = copy_strings(bprm->argc, argv, bprm); | |
1345 | if (retval < 0) | |
1346 | goto out; | |
1347 | ||
7b34e428 | 1348 | current->flags &= ~PF_KTHREAD; |
1da177e4 | 1349 | retval = search_binary_handler(bprm,regs); |
a6f76f23 DH |
1350 | if (retval < 0) |
1351 | goto out; | |
1da177e4 | 1352 | |
a6f76f23 | 1353 | /* execve succeeded */ |
498052bb | 1354 | current->fs->in_exec = 0; |
f9ce1f1c | 1355 | current->in_execve = 0; |
a6f76f23 DH |
1356 | mutex_unlock(¤t->cred_exec_mutex); |
1357 | acct_update_integrals(current); | |
1358 | free_bprm(bprm); | |
1359 | if (displaced) | |
1360 | put_files_struct(displaced); | |
1361 | return retval; | |
1da177e4 | 1362 | |
a6f76f23 | 1363 | out: |
1da177e4 | 1364 | if (bprm->mm) |
b6a2fea3 | 1365 | mmput (bprm->mm); |
1da177e4 LT |
1366 | |
1367 | out_file: | |
1368 | if (bprm->file) { | |
1369 | allow_write_access(bprm->file); | |
1370 | fput(bprm->file); | |
1371 | } | |
a6f76f23 | 1372 | |
498052bb | 1373 | out_unmark: |
8c652f96 ON |
1374 | if (clear_in_exec) |
1375 | current->fs->in_exec = 0; | |
498052bb | 1376 | |
a6f76f23 | 1377 | out_unlock: |
f9ce1f1c | 1378 | current->in_execve = 0; |
a6f76f23 DH |
1379 | mutex_unlock(¤t->cred_exec_mutex); |
1380 | ||
1381 | out_free: | |
08a6fac1 | 1382 | free_bprm(bprm); |
1da177e4 | 1383 | |
fd8328be | 1384 | out_files: |
3b125388 AV |
1385 | if (displaced) |
1386 | reset_files_struct(displaced); | |
1da177e4 LT |
1387 | out_ret: |
1388 | return retval; | |
1389 | } | |
1390 | ||
1391 | int set_binfmt(struct linux_binfmt *new) | |
1392 | { | |
1393 | struct linux_binfmt *old = current->binfmt; | |
1394 | ||
1395 | if (new) { | |
1396 | if (!try_module_get(new->module)) | |
1397 | return -1; | |
1398 | } | |
1399 | current->binfmt = new; | |
1400 | if (old) | |
1401 | module_put(old->module); | |
1402 | return 0; | |
1403 | } | |
1404 | ||
1405 | EXPORT_SYMBOL(set_binfmt); | |
1406 | ||
1da177e4 LT |
1407 | /* format_corename will inspect the pattern parameter, and output a |
1408 | * name into corename, which must have space for at least | |
1409 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1410 | */ | |
6409324b | 1411 | static int format_corename(char *corename, long signr) |
1da177e4 | 1412 | { |
86a264ab | 1413 | const struct cred *cred = current_cred(); |
565b9b14 ON |
1414 | const char *pat_ptr = core_pattern; |
1415 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 LT |
1416 | char *out_ptr = corename; |
1417 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1418 | int rc; | |
1419 | int pid_in_pattern = 0; | |
1420 | ||
1421 | /* Repeat as long as we have more pattern to process and more output | |
1422 | space */ | |
1423 | while (*pat_ptr) { | |
1424 | if (*pat_ptr != '%') { | |
1425 | if (out_ptr == out_end) | |
1426 | goto out; | |
1427 | *out_ptr++ = *pat_ptr++; | |
1428 | } else { | |
1429 | switch (*++pat_ptr) { | |
1430 | case 0: | |
1431 | goto out; | |
1432 | /* Double percent, output one percent */ | |
1433 | case '%': | |
1434 | if (out_ptr == out_end) | |
1435 | goto out; | |
1436 | *out_ptr++ = '%'; | |
1437 | break; | |
1438 | /* pid */ | |
1439 | case 'p': | |
1440 | pid_in_pattern = 1; | |
1441 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1442 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1443 | if (rc > out_end - out_ptr) |
1444 | goto out; | |
1445 | out_ptr += rc; | |
1446 | break; | |
1447 | /* uid */ | |
1448 | case 'u': | |
1449 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1450 | "%d", cred->uid); |
1da177e4 LT |
1451 | if (rc > out_end - out_ptr) |
1452 | goto out; | |
1453 | out_ptr += rc; | |
1454 | break; | |
1455 | /* gid */ | |
1456 | case 'g': | |
1457 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1458 | "%d", cred->gid); |
1da177e4 LT |
1459 | if (rc > out_end - out_ptr) |
1460 | goto out; | |
1461 | out_ptr += rc; | |
1462 | break; | |
1463 | /* signal that caused the coredump */ | |
1464 | case 's': | |
1465 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1466 | "%ld", signr); | |
1467 | if (rc > out_end - out_ptr) | |
1468 | goto out; | |
1469 | out_ptr += rc; | |
1470 | break; | |
1471 | /* UNIX time of coredump */ | |
1472 | case 't': { | |
1473 | struct timeval tv; | |
1474 | do_gettimeofday(&tv); | |
1475 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1476 | "%lu", tv.tv_sec); | |
1477 | if (rc > out_end - out_ptr) | |
1478 | goto out; | |
1479 | out_ptr += rc; | |
1480 | break; | |
1481 | } | |
1482 | /* hostname */ | |
1483 | case 'h': | |
1484 | down_read(&uts_sem); | |
1485 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1486 | "%s", utsname()->nodename); |
1da177e4 LT |
1487 | up_read(&uts_sem); |
1488 | if (rc > out_end - out_ptr) | |
1489 | goto out; | |
1490 | out_ptr += rc; | |
1491 | break; | |
1492 | /* executable */ | |
1493 | case 'e': | |
1494 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1495 | "%s", current->comm); | |
1496 | if (rc > out_end - out_ptr) | |
1497 | goto out; | |
1498 | out_ptr += rc; | |
1499 | break; | |
74aadce9 NH |
1500 | /* core limit size */ |
1501 | case 'c': | |
1502 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1503 | "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); | |
1504 | if (rc > out_end - out_ptr) | |
1505 | goto out; | |
1506 | out_ptr += rc; | |
1507 | break; | |
1da177e4 LT |
1508 | default: |
1509 | break; | |
1510 | } | |
1511 | ++pat_ptr; | |
1512 | } | |
1513 | } | |
1514 | /* Backward compatibility with core_uses_pid: | |
1515 | * | |
1516 | * If core_pattern does not include a %p (as is the default) | |
1517 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1518 | * the filename. Do not do this for piped commands. */ |
6409324b | 1519 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1da177e4 | 1520 | rc = snprintf(out_ptr, out_end - out_ptr, |
b488893a | 1521 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1522 | if (rc > out_end - out_ptr) |
1523 | goto out; | |
1524 | out_ptr += rc; | |
1525 | } | |
c4bbafda | 1526 | out: |
1da177e4 | 1527 | *out_ptr = 0; |
c4bbafda | 1528 | return ispipe; |
1da177e4 LT |
1529 | } |
1530 | ||
8cd9c249 | 1531 | static int zap_process(struct task_struct *start) |
aceecc04 ON |
1532 | { |
1533 | struct task_struct *t; | |
8cd9c249 | 1534 | int nr = 0; |
281de339 | 1535 | |
d5f70c00 ON |
1536 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1537 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1538 | |
1539 | t = start; | |
1540 | do { | |
1541 | if (t != current && t->mm) { | |
281de339 ON |
1542 | sigaddset(&t->pending.signal, SIGKILL); |
1543 | signal_wake_up(t, 1); | |
8cd9c249 | 1544 | nr++; |
aceecc04 | 1545 | } |
e4901f92 | 1546 | } while_each_thread(start, t); |
8cd9c249 ON |
1547 | |
1548 | return nr; | |
aceecc04 ON |
1549 | } |
1550 | ||
dcf560c5 | 1551 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1552 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1553 | { |
1554 | struct task_struct *g, *p; | |
5debfa6d | 1555 | unsigned long flags; |
8cd9c249 | 1556 | int nr = -EAGAIN; |
dcf560c5 ON |
1557 | |
1558 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1559 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1560 | mm->core_state = core_state; |
dcf560c5 | 1561 | tsk->signal->group_exit_code = exit_code; |
8cd9c249 | 1562 | nr = zap_process(tsk); |
1da177e4 | 1563 | } |
dcf560c5 | 1564 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1565 | if (unlikely(nr < 0)) |
1566 | return nr; | |
1da177e4 | 1567 | |
8cd9c249 | 1568 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1569 | goto done; |
e4901f92 ON |
1570 | /* |
1571 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1572 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1573 | * lock, but this is safe wrt: |
1574 | * | |
1575 | * fork: | |
1576 | * None of sub-threads can fork after zap_process(leader). All | |
1577 | * processes which were created before this point should be | |
1578 | * visible to zap_threads() because copy_process() adds the new | |
1579 | * process to the tail of init_task.tasks list, and lock/unlock | |
1580 | * of ->siglock provides a memory barrier. | |
1581 | * | |
1582 | * do_exit: | |
1583 | * The caller holds mm->mmap_sem. This means that the task which | |
1584 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1585 | * its ->mm. | |
1586 | * | |
1587 | * de_thread: | |
1588 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1589 | * we must see either old or new leader, this does not matter. | |
1590 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1591 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1592 | * it can't fail. | |
1593 | * | |
1594 | * Note also that "g" can be the old leader with ->mm == NULL | |
1595 | * and already unhashed and thus removed from ->thread_group. | |
1596 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1597 | * clear the ->next pointer, we will find the new leader via | |
1598 | * next_thread(). | |
1599 | */ | |
7b1c6154 | 1600 | rcu_read_lock(); |
aceecc04 | 1601 | for_each_process(g) { |
5debfa6d ON |
1602 | if (g == tsk->group_leader) |
1603 | continue; | |
15b9f360 ON |
1604 | if (g->flags & PF_KTHREAD) |
1605 | continue; | |
aceecc04 ON |
1606 | p = g; |
1607 | do { | |
1608 | if (p->mm) { | |
15b9f360 | 1609 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1610 | lock_task_sighand(p, &flags); |
8cd9c249 | 1611 | nr += zap_process(p); |
5debfa6d ON |
1612 | unlock_task_sighand(p, &flags); |
1613 | } | |
aceecc04 ON |
1614 | break; |
1615 | } | |
e4901f92 | 1616 | } while_each_thread(g, p); |
aceecc04 | 1617 | } |
7b1c6154 | 1618 | rcu_read_unlock(); |
5debfa6d | 1619 | done: |
c5f1cc8c | 1620 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1621 | return nr; |
1da177e4 LT |
1622 | } |
1623 | ||
9d5b327b | 1624 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1625 | { |
dcf560c5 ON |
1626 | struct task_struct *tsk = current; |
1627 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1628 | struct completion *vfork_done; |
2384f55f | 1629 | int core_waiters; |
1da177e4 | 1630 | |
9d5b327b | 1631 | init_completion(&core_state->startup); |
b564daf8 ON |
1632 | core_state->dumper.task = tsk; |
1633 | core_state->dumper.next = NULL; | |
9d5b327b | 1634 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
2384f55f ON |
1635 | up_write(&mm->mmap_sem); |
1636 | ||
dcf560c5 ON |
1637 | if (unlikely(core_waiters < 0)) |
1638 | goto fail; | |
1639 | ||
1640 | /* | |
1641 | * Make sure nobody is waiting for us to release the VM, | |
1642 | * otherwise we can deadlock when we wait on each other | |
1643 | */ | |
1644 | vfork_done = tsk->vfork_done; | |
1645 | if (vfork_done) { | |
1646 | tsk->vfork_done = NULL; | |
1647 | complete(vfork_done); | |
1648 | } | |
1649 | ||
2384f55f | 1650 | if (core_waiters) |
9d5b327b | 1651 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1652 | fail: |
dcf560c5 | 1653 | return core_waiters; |
1da177e4 LT |
1654 | } |
1655 | ||
a94e2d40 ON |
1656 | static void coredump_finish(struct mm_struct *mm) |
1657 | { | |
1658 | struct core_thread *curr, *next; | |
1659 | struct task_struct *task; | |
1660 | ||
1661 | next = mm->core_state->dumper.next; | |
1662 | while ((curr = next) != NULL) { | |
1663 | next = curr->next; | |
1664 | task = curr->task; | |
1665 | /* | |
1666 | * see exit_mm(), curr->task must not see | |
1667 | * ->task == NULL before we read ->next. | |
1668 | */ | |
1669 | smp_mb(); | |
1670 | curr->task = NULL; | |
1671 | wake_up_process(task); | |
1672 | } | |
1673 | ||
1674 | mm->core_state = NULL; | |
1675 | } | |
1676 | ||
6c5d5238 KH |
1677 | /* |
1678 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1679 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1680 | * these bits are not changed atomically. So get_dumpable can observe the | |
1681 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1682 | * return either old dumpable or new one by paying attention to the order of | |
1683 | * modifying the bits. | |
1684 | * | |
1685 | * dumpable | mm->flags (binary) | |
1686 | * old new | initial interim final | |
1687 | * ---------+----------------------- | |
1688 | * 0 1 | 00 01 01 | |
1689 | * 0 2 | 00 10(*) 11 | |
1690 | * 1 0 | 01 00 00 | |
1691 | * 1 2 | 01 11 11 | |
1692 | * 2 0 | 11 10(*) 00 | |
1693 | * 2 1 | 11 11 01 | |
1694 | * | |
1695 | * (*) get_dumpable regards interim value of 10 as 11. | |
1696 | */ | |
1697 | void set_dumpable(struct mm_struct *mm, int value) | |
1698 | { | |
1699 | switch (value) { | |
1700 | case 0: | |
1701 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1702 | smp_wmb(); | |
1703 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1704 | break; | |
1705 | case 1: | |
1706 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1707 | smp_wmb(); | |
1708 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1709 | break; | |
1710 | case 2: | |
1711 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1712 | smp_wmb(); | |
1713 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1714 | break; | |
1715 | } | |
1716 | } | |
6c5d5238 KH |
1717 | |
1718 | int get_dumpable(struct mm_struct *mm) | |
1719 | { | |
1720 | int ret; | |
1721 | ||
1722 | ret = mm->flags & 0x3; | |
1723 | return (ret >= 2) ? 2 : ret; | |
1724 | } | |
1725 | ||
8cd3ac3a | 1726 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1da177e4 | 1727 | { |
9d5b327b | 1728 | struct core_state core_state; |
1da177e4 LT |
1729 | char corename[CORENAME_MAX_SIZE + 1]; |
1730 | struct mm_struct *mm = current->mm; | |
1731 | struct linux_binfmt * binfmt; | |
1732 | struct inode * inode; | |
1733 | struct file * file; | |
d84f4f99 DH |
1734 | const struct cred *old_cred; |
1735 | struct cred *cred; | |
1da177e4 | 1736 | int retval = 0; |
d6e71144 | 1737 | int flag = 0; |
d025c9db | 1738 | int ispipe = 0; |
7dc0b22e | 1739 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
74aadce9 NH |
1740 | char **helper_argv = NULL; |
1741 | int helper_argc = 0; | |
1742 | char *delimit; | |
1da177e4 | 1743 | |
0a4ff8c2 SG |
1744 | audit_core_dumps(signr); |
1745 | ||
1da177e4 LT |
1746 | binfmt = current->binfmt; |
1747 | if (!binfmt || !binfmt->core_dump) | |
1748 | goto fail; | |
d84f4f99 DH |
1749 | |
1750 | cred = prepare_creds(); | |
1751 | if (!cred) { | |
1752 | retval = -ENOMEM; | |
1753 | goto fail; | |
1754 | } | |
1755 | ||
1da177e4 | 1756 | down_write(&mm->mmap_sem); |
00ec99da RM |
1757 | /* |
1758 | * If another thread got here first, or we are not dumpable, bail out. | |
1759 | */ | |
999d9fc1 | 1760 | if (mm->core_state || !get_dumpable(mm)) { |
1da177e4 | 1761 | up_write(&mm->mmap_sem); |
d84f4f99 | 1762 | put_cred(cred); |
1da177e4 LT |
1763 | goto fail; |
1764 | } | |
d6e71144 AC |
1765 | |
1766 | /* | |
1767 | * We cannot trust fsuid as being the "true" uid of the | |
1768 | * process nor do we know its entire history. We only know it | |
1769 | * was tainted so we dump it as root in mode 2. | |
1770 | */ | |
6c5d5238 | 1771 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 | 1772 | flag = O_EXCL; /* Stop rewrite attacks */ |
d84f4f99 | 1773 | cred->fsuid = 0; /* Dump root private */ |
d6e71144 | 1774 | } |
1291cf41 | 1775 | |
9d5b327b | 1776 | retval = coredump_wait(exit_code, &core_state); |
d84f4f99 DH |
1777 | if (retval < 0) { |
1778 | put_cred(cred); | |
1291cf41 | 1779 | goto fail; |
d84f4f99 DH |
1780 | } |
1781 | ||
1782 | old_cred = override_creds(cred); | |
1da177e4 LT |
1783 | |
1784 | /* | |
1785 | * Clear any false indication of pending signals that might | |
1786 | * be seen by the filesystem code called to write the core file. | |
1787 | */ | |
1da177e4 LT |
1788 | clear_thread_flag(TIF_SIGPENDING); |
1789 | ||
1da177e4 LT |
1790 | /* |
1791 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1792 | * uses lock_kernel() | |
1793 | */ | |
1794 | lock_kernel(); | |
6409324b | 1795 | ispipe = format_corename(corename, signr); |
1da177e4 | 1796 | unlock_kernel(); |
7dc0b22e NH |
1797 | /* |
1798 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1799 | * to a pipe. Since we're not writing directly to the filesystem | |
1800 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1801 | * created unless the pipe reader choses to write out the core file | |
1802 | * at which point file size limits and permissions will be imposed | |
1803 | * as it does with any other process | |
1804 | */ | |
74aadce9 | 1805 | if ((!ispipe) && (core_limit < binfmt->min_coredump)) |
7dc0b22e NH |
1806 | goto fail_unlock; |
1807 | ||
c4bbafda | 1808 | if (ispipe) { |
74aadce9 | 1809 | helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc); |
350eaf79 TH |
1810 | if (!helper_argv) { |
1811 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
1812 | __func__); | |
1813 | goto fail_unlock; | |
1814 | } | |
74aadce9 NH |
1815 | /* Terminate the string before the first option */ |
1816 | delimit = strchr(corename, ' '); | |
1817 | if (delimit) | |
1818 | *delimit = '\0'; | |
32321137 NH |
1819 | delimit = strrchr(helper_argv[0], '/'); |
1820 | if (delimit) | |
1821 | delimit++; | |
1822 | else | |
1823 | delimit = helper_argv[0]; | |
1824 | if (!strcmp(delimit, current->comm)) { | |
1825 | printk(KERN_NOTICE "Recursive core dump detected, " | |
1826 | "aborting\n"); | |
1827 | goto fail_unlock; | |
1828 | } | |
1829 | ||
1830 | core_limit = RLIM_INFINITY; | |
1831 | ||
d025c9db | 1832 | /* SIGPIPE can happen, but it's just never processed */ |
32321137 NH |
1833 | if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, |
1834 | &file)) { | |
d025c9db AK |
1835 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1836 | corename); | |
1837 | goto fail_unlock; | |
1838 | } | |
d025c9db AK |
1839 | } else |
1840 | file = filp_open(corename, | |
6d4df677 AD |
1841 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1842 | 0600); | |
1da177e4 LT |
1843 | if (IS_ERR(file)) |
1844 | goto fail_unlock; | |
0f7fc9e4 | 1845 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1846 | if (inode->i_nlink > 1) |
1847 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1848 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1849 | goto close_fail; |
1850 | ||
d025c9db AK |
1851 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1852 | but keep the previous behaviour for now. */ | |
1853 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 | 1854 | goto close_fail; |
c46f739d IM |
1855 | /* |
1856 | * Dont allow local users get cute and trick others to coredump | |
1857 | * into their pre-created files: | |
1858 | */ | |
da9592ed | 1859 | if (inode->i_uid != current_fsuid()) |
c46f739d | 1860 | goto close_fail; |
1da177e4 LT |
1861 | if (!file->f_op) |
1862 | goto close_fail; | |
1863 | if (!file->f_op->write) | |
1864 | goto close_fail; | |
0f7fc9e4 | 1865 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1866 | goto close_fail; |
1867 | ||
7dc0b22e | 1868 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1869 | |
1870 | if (retval) | |
1871 | current->signal->group_exit_code |= 0x80; | |
1872 | close_fail: | |
1873 | filp_close(file, NULL); | |
1874 | fail_unlock: | |
74aadce9 NH |
1875 | if (helper_argv) |
1876 | argv_free(helper_argv); | |
1877 | ||
d84f4f99 DH |
1878 | revert_creds(old_cred); |
1879 | put_cred(cred); | |
a94e2d40 | 1880 | coredump_finish(mm); |
1da177e4 | 1881 | fail: |
8cd3ac3a | 1882 | return; |
1da177e4 | 1883 | } |