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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> |
1da177e4 LT |
35 | #include <linux/highmem.h> |
36 | #include <linux/spinlock.h> | |
37 | #include <linux/key.h> | |
38 | #include <linux/personality.h> | |
39 | #include <linux/binfmts.h> | |
1da177e4 | 40 | #include <linux/utsname.h> |
84d73786 | 41 | #include <linux/pid_namespace.h> |
1da177e4 LT |
42 | #include <linux/module.h> |
43 | #include <linux/namei.h> | |
44 | #include <linux/proc_fs.h> | |
45 | #include <linux/ptrace.h> | |
46 | #include <linux/mount.h> | |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
8f0ab514 | 49 | #include <linux/tsacct_kern.h> |
9f46080c | 50 | #include <linux/cn_proc.h> |
473ae30b | 51 | #include <linux/audit.h> |
1da177e4 LT |
52 | |
53 | #include <asm/uaccess.h> | |
54 | #include <asm/mmu_context.h> | |
b6a2fea3 | 55 | #include <asm/tlb.h> |
1da177e4 LT |
56 | |
57 | #ifdef CONFIG_KMOD | |
58 | #include <linux/kmod.h> | |
59 | #endif | |
60 | ||
702773b1 DW |
61 | #ifdef __alpha__ |
62 | /* for /sbin/loader handling in search_binary_handler() */ | |
63 | #include <linux/a.out.h> | |
64 | #endif | |
65 | ||
1da177e4 | 66 | int core_uses_pid; |
71ce92f3 | 67 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
d6e71144 AC |
68 | int suid_dumpable = 0; |
69 | ||
1da177e4 LT |
70 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
71 | ||
e4dc1b14 | 72 | static LIST_HEAD(formats); |
1da177e4 LT |
73 | static DEFINE_RWLOCK(binfmt_lock); |
74 | ||
75 | int register_binfmt(struct linux_binfmt * fmt) | |
76 | { | |
1da177e4 LT |
77 | if (!fmt) |
78 | return -EINVAL; | |
1da177e4 | 79 | write_lock(&binfmt_lock); |
e4dc1b14 | 80 | list_add(&fmt->lh, &formats); |
1da177e4 LT |
81 | write_unlock(&binfmt_lock); |
82 | return 0; | |
83 | } | |
84 | ||
85 | EXPORT_SYMBOL(register_binfmt); | |
86 | ||
f6b450d4 | 87 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 88 | { |
1da177e4 | 89 | write_lock(&binfmt_lock); |
e4dc1b14 | 90 | list_del(&fmt->lh); |
1da177e4 | 91 | write_unlock(&binfmt_lock); |
1da177e4 LT |
92 | } |
93 | ||
94 | EXPORT_SYMBOL(unregister_binfmt); | |
95 | ||
96 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
97 | { | |
98 | module_put(fmt->module); | |
99 | } | |
100 | ||
101 | /* | |
102 | * Note that a shared library must be both readable and executable due to | |
103 | * security reasons. | |
104 | * | |
105 | * Also note that we take the address to load from from the file itself. | |
106 | */ | |
107 | asmlinkage long sys_uselib(const char __user * library) | |
108 | { | |
109 | struct file * file; | |
110 | struct nameidata nd; | |
111 | int error; | |
112 | ||
b500531e | 113 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
114 | if (error) |
115 | goto out; | |
116 | ||
117 | error = -EINVAL; | |
4ac91378 | 118 | if (!S_ISREG(nd.path.dentry->d_inode->i_mode)) |
1da177e4 LT |
119 | goto exit; |
120 | ||
e4543edd | 121 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC); |
1da177e4 LT |
122 | if (error) |
123 | goto exit; | |
124 | ||
abe8be3a | 125 | file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE); |
1da177e4 LT |
126 | error = PTR_ERR(file); |
127 | if (IS_ERR(file)) | |
128 | goto out; | |
129 | ||
130 | error = -ENOEXEC; | |
131 | if(file->f_op) { | |
132 | struct linux_binfmt * fmt; | |
133 | ||
134 | read_lock(&binfmt_lock); | |
e4dc1b14 | 135 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
136 | if (!fmt->load_shlib) |
137 | continue; | |
138 | if (!try_module_get(fmt->module)) | |
139 | continue; | |
140 | read_unlock(&binfmt_lock); | |
141 | error = fmt->load_shlib(file); | |
142 | read_lock(&binfmt_lock); | |
143 | put_binfmt(fmt); | |
144 | if (error != -ENOEXEC) | |
145 | break; | |
146 | } | |
147 | read_unlock(&binfmt_lock); | |
148 | } | |
149 | fput(file); | |
150 | out: | |
151 | return error; | |
152 | exit: | |
834f2a4a | 153 | release_open_intent(&nd); |
1d957f9b | 154 | path_put(&nd.path); |
1da177e4 LT |
155 | goto out; |
156 | } | |
157 | ||
b6a2fea3 OW |
158 | #ifdef CONFIG_MMU |
159 | ||
160 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
161 | int write) | |
162 | { | |
163 | struct page *page; | |
164 | int ret; | |
165 | ||
166 | #ifdef CONFIG_STACK_GROWSUP | |
167 | if (write) { | |
168 | ret = expand_stack_downwards(bprm->vma, pos); | |
169 | if (ret < 0) | |
170 | return NULL; | |
171 | } | |
172 | #endif | |
173 | ret = get_user_pages(current, bprm->mm, pos, | |
174 | 1, write, 1, &page, NULL); | |
175 | if (ret <= 0) | |
176 | return NULL; | |
177 | ||
178 | if (write) { | |
b6a2fea3 | 179 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
180 | struct rlimit *rlim; |
181 | ||
182 | /* | |
183 | * We've historically supported up to 32 pages (ARG_MAX) | |
184 | * of argument strings even with small stacks | |
185 | */ | |
186 | if (size <= ARG_MAX) | |
187 | return page; | |
b6a2fea3 OW |
188 | |
189 | /* | |
190 | * Limit to 1/4-th the stack size for the argv+env strings. | |
191 | * This ensures that: | |
192 | * - the remaining binfmt code will not run out of stack space, | |
193 | * - the program will have a reasonable amount of stack left | |
194 | * to work from. | |
195 | */ | |
a64e715f | 196 | rlim = current->signal->rlim; |
b6a2fea3 OW |
197 | if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { |
198 | put_page(page); | |
199 | return NULL; | |
200 | } | |
201 | } | |
202 | ||
203 | return page; | |
204 | } | |
205 | ||
206 | static void put_arg_page(struct page *page) | |
207 | { | |
208 | put_page(page); | |
209 | } | |
210 | ||
211 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
212 | { | |
213 | } | |
214 | ||
215 | static void free_arg_pages(struct linux_binprm *bprm) | |
216 | { | |
217 | } | |
218 | ||
219 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
220 | struct page *page) | |
221 | { | |
222 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
223 | } | |
224 | ||
225 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
226 | { | |
227 | int err = -ENOMEM; | |
228 | struct vm_area_struct *vma = NULL; | |
229 | struct mm_struct *mm = bprm->mm; | |
230 | ||
231 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
232 | if (!vma) | |
233 | goto err; | |
234 | ||
235 | down_write(&mm->mmap_sem); | |
236 | vma->vm_mm = mm; | |
237 | ||
238 | /* | |
239 | * Place the stack at the largest stack address the architecture | |
240 | * supports. Later, we'll move this to an appropriate place. We don't | |
241 | * use STACK_TOP because that can depend on attributes which aren't | |
242 | * configured yet. | |
243 | */ | |
244 | vma->vm_end = STACK_TOP_MAX; | |
245 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
246 | ||
247 | vma->vm_flags = VM_STACK_FLAGS; | |
3ed75eb8 | 248 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
b6a2fea3 OW |
249 | err = insert_vm_struct(mm, vma); |
250 | if (err) { | |
251 | up_write(&mm->mmap_sem); | |
252 | goto err; | |
253 | } | |
254 | ||
255 | mm->stack_vm = mm->total_vm = 1; | |
256 | up_write(&mm->mmap_sem); | |
257 | ||
258 | bprm->p = vma->vm_end - sizeof(void *); | |
259 | ||
260 | return 0; | |
261 | ||
262 | err: | |
263 | if (vma) { | |
264 | bprm->vma = NULL; | |
265 | kmem_cache_free(vm_area_cachep, vma); | |
266 | } | |
267 | ||
268 | return err; | |
269 | } | |
270 | ||
271 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
272 | { | |
273 | return len <= MAX_ARG_STRLEN; | |
274 | } | |
275 | ||
276 | #else | |
277 | ||
278 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
279 | int write) | |
280 | { | |
281 | struct page *page; | |
282 | ||
283 | page = bprm->page[pos / PAGE_SIZE]; | |
284 | if (!page && write) { | |
285 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
286 | if (!page) | |
287 | return NULL; | |
288 | bprm->page[pos / PAGE_SIZE] = page; | |
289 | } | |
290 | ||
291 | return page; | |
292 | } | |
293 | ||
294 | static void put_arg_page(struct page *page) | |
295 | { | |
296 | } | |
297 | ||
298 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
299 | { | |
300 | if (bprm->page[i]) { | |
301 | __free_page(bprm->page[i]); | |
302 | bprm->page[i] = NULL; | |
303 | } | |
304 | } | |
305 | ||
306 | static void free_arg_pages(struct linux_binprm *bprm) | |
307 | { | |
308 | int i; | |
309 | ||
310 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
311 | free_arg_page(bprm, i); | |
312 | } | |
313 | ||
314 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
315 | struct page *page) | |
316 | { | |
317 | } | |
318 | ||
319 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
320 | { | |
321 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
322 | return 0; | |
323 | } | |
324 | ||
325 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
326 | { | |
327 | return len <= bprm->p; | |
328 | } | |
329 | ||
330 | #endif /* CONFIG_MMU */ | |
331 | ||
332 | /* | |
333 | * Create a new mm_struct and populate it with a temporary stack | |
334 | * vm_area_struct. We don't have enough context at this point to set the stack | |
335 | * flags, permissions, and offset, so we use temporary values. We'll update | |
336 | * them later in setup_arg_pages(). | |
337 | */ | |
338 | int bprm_mm_init(struct linux_binprm *bprm) | |
339 | { | |
340 | int err; | |
341 | struct mm_struct *mm = NULL; | |
342 | ||
343 | bprm->mm = mm = mm_alloc(); | |
344 | err = -ENOMEM; | |
345 | if (!mm) | |
346 | goto err; | |
347 | ||
348 | err = init_new_context(current, mm); | |
349 | if (err) | |
350 | goto err; | |
351 | ||
352 | err = __bprm_mm_init(bprm); | |
353 | if (err) | |
354 | goto err; | |
355 | ||
356 | return 0; | |
357 | ||
358 | err: | |
359 | if (mm) { | |
360 | bprm->mm = NULL; | |
361 | mmdrop(mm); | |
362 | } | |
363 | ||
364 | return err; | |
365 | } | |
366 | ||
1da177e4 LT |
367 | /* |
368 | * count() counts the number of strings in array ARGV. | |
369 | */ | |
370 | static int count(char __user * __user * argv, int max) | |
371 | { | |
372 | int i = 0; | |
373 | ||
374 | if (argv != NULL) { | |
375 | for (;;) { | |
376 | char __user * p; | |
377 | ||
378 | if (get_user(p, argv)) | |
379 | return -EFAULT; | |
380 | if (!p) | |
381 | break; | |
382 | argv++; | |
383 | if(++i > max) | |
384 | return -E2BIG; | |
385 | cond_resched(); | |
386 | } | |
387 | } | |
388 | return i; | |
389 | } | |
390 | ||
391 | /* | |
b6a2fea3 OW |
392 | * 'copy_strings()' copies argument/environment strings from the old |
393 | * processes's memory to the new process's stack. The call to get_user_pages() | |
394 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 395 | */ |
75c96f85 AB |
396 | static int copy_strings(int argc, char __user * __user * argv, |
397 | struct linux_binprm *bprm) | |
1da177e4 LT |
398 | { |
399 | struct page *kmapped_page = NULL; | |
400 | char *kaddr = NULL; | |
b6a2fea3 | 401 | unsigned long kpos = 0; |
1da177e4 LT |
402 | int ret; |
403 | ||
404 | while (argc-- > 0) { | |
405 | char __user *str; | |
406 | int len; | |
407 | unsigned long pos; | |
408 | ||
409 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 410 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
411 | ret = -EFAULT; |
412 | goto out; | |
413 | } | |
414 | ||
b6a2fea3 | 415 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
416 | ret = -E2BIG; |
417 | goto out; | |
418 | } | |
419 | ||
b6a2fea3 | 420 | /* We're going to work our way backwords. */ |
1da177e4 | 421 | pos = bprm->p; |
b6a2fea3 OW |
422 | str += len; |
423 | bprm->p -= len; | |
1da177e4 LT |
424 | |
425 | while (len > 0) { | |
1da177e4 | 426 | int offset, bytes_to_copy; |
1da177e4 LT |
427 | |
428 | offset = pos % PAGE_SIZE; | |
b6a2fea3 OW |
429 | if (offset == 0) |
430 | offset = PAGE_SIZE; | |
431 | ||
432 | bytes_to_copy = offset; | |
433 | if (bytes_to_copy > len) | |
434 | bytes_to_copy = len; | |
435 | ||
436 | offset -= bytes_to_copy; | |
437 | pos -= bytes_to_copy; | |
438 | str -= bytes_to_copy; | |
439 | len -= bytes_to_copy; | |
440 | ||
441 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
442 | struct page *page; | |
443 | ||
444 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 445 | if (!page) { |
b6a2fea3 | 446 | ret = -E2BIG; |
1da177e4 LT |
447 | goto out; |
448 | } | |
1da177e4 | 449 | |
b6a2fea3 OW |
450 | if (kmapped_page) { |
451 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 452 | kunmap(kmapped_page); |
b6a2fea3 OW |
453 | put_arg_page(kmapped_page); |
454 | } | |
1da177e4 LT |
455 | kmapped_page = page; |
456 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
457 | kpos = pos & PAGE_MASK; |
458 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 459 | } |
b6a2fea3 | 460 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
461 | ret = -EFAULT; |
462 | goto out; | |
463 | } | |
1da177e4 LT |
464 | } |
465 | } | |
466 | ret = 0; | |
467 | out: | |
b6a2fea3 OW |
468 | if (kmapped_page) { |
469 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 470 | kunmap(kmapped_page); |
b6a2fea3 OW |
471 | put_arg_page(kmapped_page); |
472 | } | |
1da177e4 LT |
473 | return ret; |
474 | } | |
475 | ||
476 | /* | |
477 | * Like copy_strings, but get argv and its values from kernel memory. | |
478 | */ | |
479 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
480 | { | |
481 | int r; | |
482 | mm_segment_t oldfs = get_fs(); | |
483 | set_fs(KERNEL_DS); | |
484 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
485 | set_fs(oldfs); | |
486 | return r; | |
487 | } | |
1da177e4 LT |
488 | EXPORT_SYMBOL(copy_strings_kernel); |
489 | ||
490 | #ifdef CONFIG_MMU | |
b6a2fea3 | 491 | |
1da177e4 | 492 | /* |
b6a2fea3 OW |
493 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
494 | * the binfmt code determines where the new stack should reside, we shift it to | |
495 | * its final location. The process proceeds as follows: | |
1da177e4 | 496 | * |
b6a2fea3 OW |
497 | * 1) Use shift to calculate the new vma endpoints. |
498 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
499 | * arguments passed to subsequent functions are consistent. | |
500 | * 3) Move vma's page tables to the new range. | |
501 | * 4) Free up any cleared pgd range. | |
502 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 503 | */ |
b6a2fea3 | 504 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
505 | { |
506 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
507 | unsigned long old_start = vma->vm_start; |
508 | unsigned long old_end = vma->vm_end; | |
509 | unsigned long length = old_end - old_start; | |
510 | unsigned long new_start = old_start - shift; | |
511 | unsigned long new_end = old_end - shift; | |
512 | struct mmu_gather *tlb; | |
1da177e4 | 513 | |
b6a2fea3 | 514 | BUG_ON(new_start > new_end); |
1da177e4 | 515 | |
b6a2fea3 OW |
516 | /* |
517 | * ensure there are no vmas between where we want to go | |
518 | * and where we are | |
519 | */ | |
520 | if (vma != find_vma(mm, new_start)) | |
521 | return -EFAULT; | |
522 | ||
523 | /* | |
524 | * cover the whole range: [new_start, old_end) | |
525 | */ | |
526 | vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); | |
527 | ||
528 | /* | |
529 | * move the page tables downwards, on failure we rely on | |
530 | * process cleanup to remove whatever mess we made. | |
531 | */ | |
532 | if (length != move_page_tables(vma, old_start, | |
533 | vma, new_start, length)) | |
534 | return -ENOMEM; | |
535 | ||
536 | lru_add_drain(); | |
537 | tlb = tlb_gather_mmu(mm, 0); | |
538 | if (new_end > old_start) { | |
539 | /* | |
540 | * when the old and new regions overlap clear from new_end. | |
541 | */ | |
42b77728 | 542 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
543 | vma->vm_next ? vma->vm_next->vm_start : 0); |
544 | } else { | |
545 | /* | |
546 | * otherwise, clean from old_start; this is done to not touch | |
547 | * the address space in [new_end, old_start) some architectures | |
548 | * have constraints on va-space that make this illegal (IA64) - | |
549 | * for the others its just a little faster. | |
550 | */ | |
42b77728 | 551 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 552 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 553 | } |
b6a2fea3 OW |
554 | tlb_finish_mmu(tlb, new_end, old_end); |
555 | ||
556 | /* | |
557 | * shrink the vma to just the new range. | |
558 | */ | |
559 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
560 | ||
561 | return 0; | |
1da177e4 LT |
562 | } |
563 | ||
564 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
565 | ||
b6a2fea3 OW |
566 | /* |
567 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
568 | * the stack is optionally relocated, and some extra space is added. | |
569 | */ | |
1da177e4 LT |
570 | int setup_arg_pages(struct linux_binprm *bprm, |
571 | unsigned long stack_top, | |
572 | int executable_stack) | |
573 | { | |
b6a2fea3 OW |
574 | unsigned long ret; |
575 | unsigned long stack_shift; | |
1da177e4 | 576 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
577 | struct vm_area_struct *vma = bprm->vma; |
578 | struct vm_area_struct *prev = NULL; | |
579 | unsigned long vm_flags; | |
580 | unsigned long stack_base; | |
1da177e4 LT |
581 | |
582 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 LT |
583 | /* Limit stack size to 1GB */ |
584 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
585 | if (stack_base > (1 << 30)) | |
586 | stack_base = 1 << 30; | |
1da177e4 | 587 | |
b6a2fea3 OW |
588 | /* Make sure we didn't let the argument array grow too large. */ |
589 | if (vma->vm_end - vma->vm_start > stack_base) | |
590 | return -ENOMEM; | |
1da177e4 | 591 | |
b6a2fea3 | 592 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 593 | |
b6a2fea3 OW |
594 | stack_shift = vma->vm_start - stack_base; |
595 | mm->arg_start = bprm->p - stack_shift; | |
596 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 597 | #else |
b6a2fea3 OW |
598 | stack_top = arch_align_stack(stack_top); |
599 | stack_top = PAGE_ALIGN(stack_top); | |
600 | stack_shift = vma->vm_end - stack_top; | |
601 | ||
602 | bprm->p -= stack_shift; | |
1da177e4 | 603 | mm->arg_start = bprm->p; |
1da177e4 LT |
604 | #endif |
605 | ||
1da177e4 | 606 | if (bprm->loader) |
b6a2fea3 OW |
607 | bprm->loader -= stack_shift; |
608 | bprm->exec -= stack_shift; | |
1da177e4 | 609 | |
1da177e4 | 610 | down_write(&mm->mmap_sem); |
96a8e13e | 611 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
612 | |
613 | /* | |
614 | * Adjust stack execute permissions; explicitly enable for | |
615 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
616 | * (arch default) otherwise. | |
617 | */ | |
618 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
619 | vm_flags |= VM_EXEC; | |
620 | else if (executable_stack == EXSTACK_DISABLE_X) | |
621 | vm_flags &= ~VM_EXEC; | |
622 | vm_flags |= mm->def_flags; | |
623 | ||
624 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
625 | vm_flags); | |
626 | if (ret) | |
627 | goto out_unlock; | |
628 | BUG_ON(prev != vma); | |
629 | ||
630 | /* Move stack pages down in memory. */ | |
631 | if (stack_shift) { | |
632 | ret = shift_arg_pages(vma, stack_shift); | |
633 | if (ret) { | |
1da177e4 | 634 | up_write(&mm->mmap_sem); |
1da177e4 LT |
635 | return ret; |
636 | } | |
1da177e4 LT |
637 | } |
638 | ||
b6a2fea3 OW |
639 | #ifdef CONFIG_STACK_GROWSUP |
640 | stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
641 | #else | |
642 | stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
643 | #endif | |
644 | ret = expand_stack(vma, stack_base); | |
645 | if (ret) | |
646 | ret = -EFAULT; | |
647 | ||
648 | out_unlock: | |
1da177e4 | 649 | up_write(&mm->mmap_sem); |
1da177e4 LT |
650 | return 0; |
651 | } | |
1da177e4 LT |
652 | EXPORT_SYMBOL(setup_arg_pages); |
653 | ||
1da177e4 LT |
654 | #endif /* CONFIG_MMU */ |
655 | ||
656 | struct file *open_exec(const char *name) | |
657 | { | |
658 | struct nameidata nd; | |
659 | int err; | |
660 | struct file *file; | |
661 | ||
b500531e | 662 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
663 | file = ERR_PTR(err); |
664 | ||
665 | if (!err) { | |
4ac91378 | 666 | struct inode *inode = nd.path.dentry->d_inode; |
1da177e4 | 667 | file = ERR_PTR(-EACCES); |
1a159dd2 | 668 | if (S_ISREG(inode->i_mode)) { |
e4543edd | 669 | int err = vfs_permission(&nd, MAY_EXEC); |
1da177e4 LT |
670 | file = ERR_PTR(err); |
671 | if (!err) { | |
abe8be3a AK |
672 | file = nameidata_to_filp(&nd, |
673 | O_RDONLY|O_LARGEFILE); | |
1da177e4 LT |
674 | if (!IS_ERR(file)) { |
675 | err = deny_write_access(file); | |
676 | if (err) { | |
677 | fput(file); | |
678 | file = ERR_PTR(err); | |
679 | } | |
680 | } | |
681 | out: | |
682 | return file; | |
683 | } | |
684 | } | |
834f2a4a | 685 | release_open_intent(&nd); |
1d957f9b | 686 | path_put(&nd.path); |
1da177e4 LT |
687 | } |
688 | goto out; | |
689 | } | |
690 | ||
691 | EXPORT_SYMBOL(open_exec); | |
692 | ||
693 | int kernel_read(struct file *file, unsigned long offset, | |
694 | char *addr, unsigned long count) | |
695 | { | |
696 | mm_segment_t old_fs; | |
697 | loff_t pos = offset; | |
698 | int result; | |
699 | ||
700 | old_fs = get_fs(); | |
701 | set_fs(get_ds()); | |
702 | /* The cast to a user pointer is valid due to the set_fs() */ | |
703 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
704 | set_fs(old_fs); | |
705 | return result; | |
706 | } | |
707 | ||
708 | EXPORT_SYMBOL(kernel_read); | |
709 | ||
710 | static int exec_mmap(struct mm_struct *mm) | |
711 | { | |
712 | struct task_struct *tsk; | |
713 | struct mm_struct * old_mm, *active_mm; | |
714 | ||
715 | /* Notify parent that we're no longer interested in the old VM */ | |
716 | tsk = current; | |
717 | old_mm = current->mm; | |
718 | mm_release(tsk, old_mm); | |
719 | ||
720 | if (old_mm) { | |
721 | /* | |
722 | * Make sure that if there is a core dump in progress | |
723 | * for the old mm, we get out and die instead of going | |
724 | * through with the exec. We must hold mmap_sem around | |
725 | * checking core_waiters and changing tsk->mm. The | |
726 | * core-inducing thread will increment core_waiters for | |
727 | * each thread whose ->mm == old_mm. | |
728 | */ | |
729 | down_read(&old_mm->mmap_sem); | |
730 | if (unlikely(old_mm->core_waiters)) { | |
731 | up_read(&old_mm->mmap_sem); | |
732 | return -EINTR; | |
733 | } | |
734 | } | |
735 | task_lock(tsk); | |
736 | active_mm = tsk->active_mm; | |
737 | tsk->mm = mm; | |
738 | tsk->active_mm = mm; | |
739 | activate_mm(active_mm, mm); | |
740 | task_unlock(tsk); | |
4cd1a8fc | 741 | mm_update_next_owner(old_mm); |
1da177e4 LT |
742 | arch_pick_mmap_layout(mm); |
743 | if (old_mm) { | |
744 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 745 | BUG_ON(active_mm != old_mm); |
1da177e4 LT |
746 | mmput(old_mm); |
747 | return 0; | |
748 | } | |
749 | mmdrop(active_mm); | |
750 | return 0; | |
751 | } | |
752 | ||
753 | /* | |
754 | * This function makes sure the current process has its own signal table, | |
755 | * so that flush_signal_handlers can later reset the handlers without | |
756 | * disturbing other processes. (Other processes might share the signal | |
757 | * table via the CLONE_SIGHAND option to clone().) | |
758 | */ | |
858119e1 | 759 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
760 | { |
761 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 762 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 763 | spinlock_t *lock = &oldsighand->siglock; |
329f7dba | 764 | struct task_struct *leader = NULL; |
1da177e4 LT |
765 | int count; |
766 | ||
aafe6c2a | 767 | if (thread_group_empty(tsk)) |
1da177e4 LT |
768 | goto no_thread_group; |
769 | ||
770 | /* | |
771 | * Kill all other threads in the thread group. | |
1da177e4 | 772 | */ |
1da177e4 | 773 | spin_lock_irq(lock); |
ed5d2cac | 774 | if (signal_group_exit(sig)) { |
1da177e4 LT |
775 | /* |
776 | * Another group action in progress, just | |
777 | * return so that the signal is processed. | |
778 | */ | |
779 | spin_unlock_irq(lock); | |
1da177e4 LT |
780 | return -EAGAIN; |
781 | } | |
ed5d2cac | 782 | sig->group_exit_task = tsk; |
aafe6c2a | 783 | zap_other_threads(tsk); |
1da177e4 | 784 | |
fea9d175 ON |
785 | /* Account for the thread group leader hanging around: */ |
786 | count = thread_group_leader(tsk) ? 1 : 2; | |
6db840fa | 787 | sig->notify_count = count; |
1da177e4 | 788 | while (atomic_read(&sig->count) > count) { |
1da177e4 LT |
789 | __set_current_state(TASK_UNINTERRUPTIBLE); |
790 | spin_unlock_irq(lock); | |
791 | schedule(); | |
792 | spin_lock_irq(lock); | |
793 | } | |
1da177e4 LT |
794 | spin_unlock_irq(lock); |
795 | ||
796 | /* | |
797 | * At this point all other threads have exited, all we have to | |
798 | * do is to wait for the thread group leader to become inactive, | |
799 | * and to assume its PID: | |
800 | */ | |
aafe6c2a | 801 | if (!thread_group_leader(tsk)) { |
aafe6c2a | 802 | leader = tsk->group_leader; |
6db840fa | 803 | |
2800d8d1 | 804 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
805 | for (;;) { |
806 | write_lock_irq(&tasklist_lock); | |
807 | if (likely(leader->exit_state)) | |
808 | break; | |
809 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
810 | write_unlock_irq(&tasklist_lock); | |
811 | schedule(); | |
812 | } | |
1da177e4 | 813 | |
7a5e873f ON |
814 | if (unlikely(task_child_reaper(tsk) == leader)) |
815 | task_active_pid_ns(tsk)->child_reaper = tsk; | |
f5e90281 RM |
816 | /* |
817 | * The only record we have of the real-time age of a | |
818 | * process, regardless of execs it's done, is start_time. | |
819 | * All the past CPU time is accumulated in signal_struct | |
820 | * from sister threads now dead. But in this non-leader | |
821 | * exec, nothing survives from the original leader thread, | |
822 | * whose birth marks the true age of this process now. | |
823 | * When we take on its identity by switching to its PID, we | |
824 | * also take its birthdate (always earlier than our own). | |
825 | */ | |
aafe6c2a | 826 | tsk->start_time = leader->start_time; |
f5e90281 | 827 | |
bac0abd6 PE |
828 | BUG_ON(!same_thread_group(leader, tsk)); |
829 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
830 | /* |
831 | * An exec() starts a new thread group with the | |
832 | * TGID of the previous thread group. Rehash the | |
833 | * two threads with a switched PID, and release | |
834 | * the former thread group leader: | |
835 | */ | |
d73d6529 EB |
836 | |
837 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
838 | * The old leader becomes a thread of the this thread group. |
839 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
840 | * is called. Odd but simple and correct. |
841 | */ | |
aafe6c2a EB |
842 | detach_pid(tsk, PIDTYPE_PID); |
843 | tsk->pid = leader->pid; | |
3743ca05 | 844 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
845 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
846 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
847 | list_replace_rcu(&leader->tasks, &tsk->tasks); | |
1da177e4 | 848 | |
aafe6c2a EB |
849 | tsk->group_leader = tsk; |
850 | leader->group_leader = tsk; | |
de12a787 | 851 | |
aafe6c2a | 852 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
853 | |
854 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
855 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
856 | |
857 | write_unlock_irq(&tasklist_lock); | |
ed5d2cac | 858 | } |
1da177e4 | 859 | |
6db840fa ON |
860 | sig->group_exit_task = NULL; |
861 | sig->notify_count = 0; | |
1da177e4 LT |
862 | |
863 | no_thread_group: | |
1da177e4 | 864 | exit_itimers(sig); |
cbaffba1 | 865 | flush_itimer_signals(); |
329f7dba ON |
866 | if (leader) |
867 | release_task(leader); | |
868 | ||
b2c903b8 ON |
869 | if (atomic_read(&oldsighand->count) != 1) { |
870 | struct sighand_struct *newsighand; | |
1da177e4 | 871 | /* |
b2c903b8 ON |
872 | * This ->sighand is shared with the CLONE_SIGHAND |
873 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 874 | */ |
b2c903b8 ON |
875 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
876 | if (!newsighand) | |
877 | return -ENOMEM; | |
878 | ||
1da177e4 LT |
879 | atomic_set(&newsighand->count, 1); |
880 | memcpy(newsighand->action, oldsighand->action, | |
881 | sizeof(newsighand->action)); | |
882 | ||
883 | write_lock_irq(&tasklist_lock); | |
884 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 885 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
886 | spin_unlock(&oldsighand->siglock); |
887 | write_unlock_irq(&tasklist_lock); | |
888 | ||
fba2afaa | 889 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
890 | } |
891 | ||
aafe6c2a | 892 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
893 | return 0; |
894 | } | |
0840a90d | 895 | |
1da177e4 LT |
896 | /* |
897 | * These functions flushes out all traces of the currently running executable | |
898 | * so that a new one can be started | |
899 | */ | |
858119e1 | 900 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
901 | { |
902 | long j = -1; | |
badf1662 | 903 | struct fdtable *fdt; |
1da177e4 LT |
904 | |
905 | spin_lock(&files->file_lock); | |
906 | for (;;) { | |
907 | unsigned long set, i; | |
908 | ||
909 | j++; | |
910 | i = j * __NFDBITS; | |
badf1662 | 911 | fdt = files_fdtable(files); |
bbea9f69 | 912 | if (i >= fdt->max_fds) |
1da177e4 | 913 | break; |
badf1662 | 914 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
915 | if (!set) |
916 | continue; | |
badf1662 | 917 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
918 | spin_unlock(&files->file_lock); |
919 | for ( ; set ; i++,set >>= 1) { | |
920 | if (set & 1) { | |
921 | sys_close(i); | |
922 | } | |
923 | } | |
924 | spin_lock(&files->file_lock); | |
925 | ||
926 | } | |
927 | spin_unlock(&files->file_lock); | |
928 | } | |
929 | ||
59714d65 | 930 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
931 | { |
932 | /* buf must be at least sizeof(tsk->comm) in size */ | |
933 | task_lock(tsk); | |
934 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
935 | task_unlock(tsk); | |
59714d65 | 936 | return buf; |
1da177e4 LT |
937 | } |
938 | ||
939 | void set_task_comm(struct task_struct *tsk, char *buf) | |
940 | { | |
941 | task_lock(tsk); | |
942 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
943 | task_unlock(tsk); | |
944 | } | |
945 | ||
946 | int flush_old_exec(struct linux_binprm * bprm) | |
947 | { | |
948 | char * name; | |
949 | int i, ch, retval; | |
1da177e4 LT |
950 | char tcomm[sizeof(current->comm)]; |
951 | ||
952 | /* | |
953 | * Make sure we have a private signal table and that | |
954 | * we are unassociated from the previous thread group. | |
955 | */ | |
956 | retval = de_thread(current); | |
957 | if (retval) | |
958 | goto out; | |
959 | ||
925d1c40 MH |
960 | set_mm_exe_file(bprm->mm, bprm->file); |
961 | ||
1da177e4 LT |
962 | /* |
963 | * Release all of the old mmap stuff | |
964 | */ | |
965 | retval = exec_mmap(bprm->mm); | |
966 | if (retval) | |
fd8328be | 967 | goto out; |
1da177e4 LT |
968 | |
969 | bprm->mm = NULL; /* We're using it now */ | |
970 | ||
971 | /* This is the point of no return */ | |
1da177e4 LT |
972 | current->sas_ss_sp = current->sas_ss_size = 0; |
973 | ||
974 | if (current->euid == current->uid && current->egid == current->gid) | |
6c5d5238 | 975 | set_dumpable(current->mm, 1); |
d6e71144 | 976 | else |
6c5d5238 | 977 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 978 | |
1da177e4 | 979 | name = bprm->filename; |
36772092 PBG |
980 | |
981 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
982 | for (i=0; (ch = *(name++)) != '\0';) { |
983 | if (ch == '/') | |
36772092 | 984 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
985 | else |
986 | if (i < (sizeof(tcomm) - 1)) | |
987 | tcomm[i++] = ch; | |
988 | } | |
989 | tcomm[i] = '\0'; | |
990 | set_task_comm(current, tcomm); | |
991 | ||
992 | current->flags &= ~PF_RANDOMIZE; | |
993 | flush_thread(); | |
994 | ||
0551fbd2 BH |
995 | /* Set the new mm task size. We have to do that late because it may |
996 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
997 | * some architectures like powerpc | |
998 | */ | |
999 | current->mm->task_size = TASK_SIZE; | |
1000 | ||
d2d56c5f MH |
1001 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { |
1002 | suid_keys(current); | |
1003 | set_dumpable(current->mm, suid_dumpable); | |
1004 | current->pdeath_signal = 0; | |
1005 | } else if (file_permission(bprm->file, MAY_READ) || | |
1006 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
1da177e4 | 1007 | suid_keys(current); |
6c5d5238 | 1008 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1009 | } |
1010 | ||
1011 | /* An exec changes our domain. We are no longer part of the thread | |
1012 | group */ | |
1013 | ||
1014 | current->self_exec_id++; | |
1015 | ||
1016 | flush_signal_handlers(current, 0); | |
1017 | flush_old_files(current->files); | |
1018 | ||
1019 | return 0; | |
1020 | ||
1da177e4 LT |
1021 | out: |
1022 | return retval; | |
1023 | } | |
1024 | ||
1025 | EXPORT_SYMBOL(flush_old_exec); | |
1026 | ||
1027 | /* | |
1028 | * Fill the binprm structure from the inode. | |
1029 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
1030 | */ | |
1031 | int prepare_binprm(struct linux_binprm *bprm) | |
1032 | { | |
1033 | int mode; | |
0f7fc9e4 | 1034 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1035 | int retval; |
1036 | ||
1037 | mode = inode->i_mode; | |
1da177e4 LT |
1038 | if (bprm->file->f_op == NULL) |
1039 | return -EACCES; | |
1040 | ||
1041 | bprm->e_uid = current->euid; | |
1042 | bprm->e_gid = current->egid; | |
1043 | ||
0f7fc9e4 | 1044 | if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1045 | /* Set-uid? */ |
1046 | if (mode & S_ISUID) { | |
1047 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1048 | bprm->e_uid = inode->i_uid; | |
1049 | } | |
1050 | ||
1051 | /* Set-gid? */ | |
1052 | /* | |
1053 | * If setgid is set but no group execute bit then this | |
1054 | * is a candidate for mandatory locking, not a setgid | |
1055 | * executable. | |
1056 | */ | |
1057 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1058 | current->personality &= ~PER_CLEAR_ON_SETID; | |
1059 | bprm->e_gid = inode->i_gid; | |
1060 | } | |
1061 | } | |
1062 | ||
1063 | /* fill in binprm security blob */ | |
1064 | retval = security_bprm_set(bprm); | |
1065 | if (retval) | |
1066 | return retval; | |
1067 | ||
1068 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
1069 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
1070 | } | |
1071 | ||
1072 | EXPORT_SYMBOL(prepare_binprm); | |
1073 | ||
858119e1 | 1074 | static int unsafe_exec(struct task_struct *p) |
1da177e4 LT |
1075 | { |
1076 | int unsafe = 0; | |
1077 | if (p->ptrace & PT_PTRACED) { | |
1078 | if (p->ptrace & PT_PTRACE_CAP) | |
1079 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
1080 | else | |
1081 | unsafe |= LSM_UNSAFE_PTRACE; | |
1082 | } | |
1083 | if (atomic_read(&p->fs->count) > 1 || | |
1084 | atomic_read(&p->files->count) > 1 || | |
1085 | atomic_read(&p->sighand->count) > 1) | |
1086 | unsafe |= LSM_UNSAFE_SHARE; | |
1087 | ||
1088 | return unsafe; | |
1089 | } | |
1090 | ||
1091 | void compute_creds(struct linux_binprm *bprm) | |
1092 | { | |
1093 | int unsafe; | |
1094 | ||
d2d56c5f | 1095 | if (bprm->e_uid != current->uid) { |
1da177e4 | 1096 | suid_keys(current); |
d2d56c5f MH |
1097 | current->pdeath_signal = 0; |
1098 | } | |
1da177e4 LT |
1099 | exec_keys(current); |
1100 | ||
1101 | task_lock(current); | |
1102 | unsafe = unsafe_exec(current); | |
1103 | security_bprm_apply_creds(bprm, unsafe); | |
1104 | task_unlock(current); | |
1105 | security_bprm_post_apply_creds(bprm); | |
1106 | } | |
1da177e4 LT |
1107 | EXPORT_SYMBOL(compute_creds); |
1108 | ||
4fc75ff4 NP |
1109 | /* |
1110 | * Arguments are '\0' separated strings found at the location bprm->p | |
1111 | * points to; chop off the first by relocating brpm->p to right after | |
1112 | * the first '\0' encountered. | |
1113 | */ | |
b6a2fea3 | 1114 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1115 | { |
b6a2fea3 OW |
1116 | int ret = 0; |
1117 | unsigned long offset; | |
1118 | char *kaddr; | |
1119 | struct page *page; | |
4fc75ff4 | 1120 | |
b6a2fea3 OW |
1121 | if (!bprm->argc) |
1122 | return 0; | |
1da177e4 | 1123 | |
b6a2fea3 OW |
1124 | do { |
1125 | offset = bprm->p & ~PAGE_MASK; | |
1126 | page = get_arg_page(bprm, bprm->p, 0); | |
1127 | if (!page) { | |
1128 | ret = -EFAULT; | |
1129 | goto out; | |
1130 | } | |
1131 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1132 | |
b6a2fea3 OW |
1133 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1134 | offset++, bprm->p++) | |
1135 | ; | |
4fc75ff4 | 1136 | |
b6a2fea3 OW |
1137 | kunmap_atomic(kaddr, KM_USER0); |
1138 | put_arg_page(page); | |
4fc75ff4 | 1139 | |
b6a2fea3 OW |
1140 | if (offset == PAGE_SIZE) |
1141 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1142 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1143 | |
b6a2fea3 OW |
1144 | bprm->p++; |
1145 | bprm->argc--; | |
1146 | ret = 0; | |
4fc75ff4 | 1147 | |
b6a2fea3 OW |
1148 | out: |
1149 | return ret; | |
1da177e4 | 1150 | } |
1da177e4 LT |
1151 | EXPORT_SYMBOL(remove_arg_zero); |
1152 | ||
1153 | /* | |
1154 | * cycle the list of binary formats handler, until one recognizes the image | |
1155 | */ | |
1156 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1157 | { | |
1158 | int try,retval; | |
1159 | struct linux_binfmt *fmt; | |
702773b1 | 1160 | #ifdef __alpha__ |
1da177e4 LT |
1161 | /* handle /sbin/loader.. */ |
1162 | { | |
1163 | struct exec * eh = (struct exec *) bprm->buf; | |
1164 | ||
1165 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1166 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1167 | { | |
1168 | struct file * file; | |
1169 | unsigned long loader; | |
1170 | ||
1171 | allow_write_access(bprm->file); | |
1172 | fput(bprm->file); | |
1173 | bprm->file = NULL; | |
1174 | ||
b6a2fea3 | 1175 | loader = bprm->vma->vm_end - sizeof(void *); |
1da177e4 LT |
1176 | |
1177 | file = open_exec("/sbin/loader"); | |
1178 | retval = PTR_ERR(file); | |
1179 | if (IS_ERR(file)) | |
1180 | return retval; | |
1181 | ||
1182 | /* Remember if the application is TASO. */ | |
1183 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1184 | ||
1185 | bprm->file = file; | |
1186 | bprm->loader = loader; | |
1187 | retval = prepare_binprm(bprm); | |
1188 | if (retval<0) | |
1189 | return retval; | |
1190 | /* should call search_binary_handler recursively here, | |
1191 | but it does not matter */ | |
1192 | } | |
1193 | } | |
1194 | #endif | |
1195 | retval = security_bprm_check(bprm); | |
1196 | if (retval) | |
1197 | return retval; | |
1198 | ||
1199 | /* kernel module loader fixup */ | |
1200 | /* so we don't try to load run modprobe in kernel space. */ | |
1201 | set_fs(USER_DS); | |
473ae30b AV |
1202 | |
1203 | retval = audit_bprm(bprm); | |
1204 | if (retval) | |
1205 | return retval; | |
1206 | ||
1da177e4 LT |
1207 | retval = -ENOENT; |
1208 | for (try=0; try<2; try++) { | |
1209 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1210 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1211 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1212 | if (!fn) | |
1213 | continue; | |
1214 | if (!try_module_get(fmt->module)) | |
1215 | continue; | |
1216 | read_unlock(&binfmt_lock); | |
1217 | retval = fn(bprm, regs); | |
1218 | if (retval >= 0) { | |
1219 | put_binfmt(fmt); | |
1220 | allow_write_access(bprm->file); | |
1221 | if (bprm->file) | |
1222 | fput(bprm->file); | |
1223 | bprm->file = NULL; | |
1224 | current->did_exec = 1; | |
9f46080c | 1225 | proc_exec_connector(current); |
1da177e4 LT |
1226 | return retval; |
1227 | } | |
1228 | read_lock(&binfmt_lock); | |
1229 | put_binfmt(fmt); | |
1230 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1231 | break; | |
1232 | if (!bprm->file) { | |
1233 | read_unlock(&binfmt_lock); | |
1234 | return retval; | |
1235 | } | |
1236 | } | |
1237 | read_unlock(&binfmt_lock); | |
1238 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1239 | break; | |
1240 | #ifdef CONFIG_KMOD | |
1241 | }else{ | |
1242 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1243 | if (printable(bprm->buf[0]) && | |
1244 | printable(bprm->buf[1]) && | |
1245 | printable(bprm->buf[2]) && | |
1246 | printable(bprm->buf[3])) | |
1247 | break; /* -ENOEXEC */ | |
1248 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1249 | #endif | |
1250 | } | |
1251 | } | |
1252 | return retval; | |
1253 | } | |
1254 | ||
1255 | EXPORT_SYMBOL(search_binary_handler); | |
1256 | ||
08a6fac1 AV |
1257 | void free_bprm(struct linux_binprm *bprm) |
1258 | { | |
1259 | free_arg_pages(bprm); | |
1260 | kfree(bprm); | |
1261 | } | |
1262 | ||
1da177e4 LT |
1263 | /* |
1264 | * sys_execve() executes a new program. | |
1265 | */ | |
1266 | int do_execve(char * filename, | |
1267 | char __user *__user *argv, | |
1268 | char __user *__user *envp, | |
1269 | struct pt_regs * regs) | |
1270 | { | |
1271 | struct linux_binprm *bprm; | |
1272 | struct file *file; | |
3b125388 | 1273 | struct files_struct *displaced; |
1da177e4 | 1274 | int retval; |
1da177e4 | 1275 | |
3b125388 | 1276 | retval = unshare_files(&displaced); |
fd8328be AV |
1277 | if (retval) |
1278 | goto out_ret; | |
1279 | ||
1da177e4 | 1280 | retval = -ENOMEM; |
11b0b5ab | 1281 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1282 | if (!bprm) |
fd8328be | 1283 | goto out_files; |
1da177e4 LT |
1284 | |
1285 | file = open_exec(filename); | |
1286 | retval = PTR_ERR(file); | |
1287 | if (IS_ERR(file)) | |
1288 | goto out_kfree; | |
1289 | ||
1290 | sched_exec(); | |
1291 | ||
1da177e4 LT |
1292 | bprm->file = file; |
1293 | bprm->filename = filename; | |
1294 | bprm->interp = filename; | |
1da177e4 | 1295 | |
b6a2fea3 OW |
1296 | retval = bprm_mm_init(bprm); |
1297 | if (retval) | |
1298 | goto out_file; | |
1da177e4 | 1299 | |
b6a2fea3 | 1300 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 LT |
1301 | if ((retval = bprm->argc) < 0) |
1302 | goto out_mm; | |
1303 | ||
b6a2fea3 | 1304 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 LT |
1305 | if ((retval = bprm->envc) < 0) |
1306 | goto out_mm; | |
1307 | ||
1308 | retval = security_bprm_alloc(bprm); | |
1309 | if (retval) | |
1310 | goto out; | |
1311 | ||
1312 | retval = prepare_binprm(bprm); | |
1313 | if (retval < 0) | |
1314 | goto out; | |
1315 | ||
1316 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1317 | if (retval < 0) | |
1318 | goto out; | |
1319 | ||
1320 | bprm->exec = bprm->p; | |
1321 | retval = copy_strings(bprm->envc, envp, bprm); | |
1322 | if (retval < 0) | |
1323 | goto out; | |
1324 | ||
1325 | retval = copy_strings(bprm->argc, argv, bprm); | |
1326 | if (retval < 0) | |
1327 | goto out; | |
1328 | ||
7b34e428 | 1329 | current->flags &= ~PF_KTHREAD; |
1da177e4 LT |
1330 | retval = search_binary_handler(bprm,regs); |
1331 | if (retval >= 0) { | |
1da177e4 LT |
1332 | /* execve success */ |
1333 | security_bprm_free(bprm); | |
1334 | acct_update_integrals(current); | |
08a6fac1 | 1335 | free_bprm(bprm); |
3b125388 AV |
1336 | if (displaced) |
1337 | put_files_struct(displaced); | |
1da177e4 LT |
1338 | return retval; |
1339 | } | |
1340 | ||
1341 | out: | |
1da177e4 LT |
1342 | if (bprm->security) |
1343 | security_bprm_free(bprm); | |
1344 | ||
1345 | out_mm: | |
1346 | if (bprm->mm) | |
b6a2fea3 | 1347 | mmput (bprm->mm); |
1da177e4 LT |
1348 | |
1349 | out_file: | |
1350 | if (bprm->file) { | |
1351 | allow_write_access(bprm->file); | |
1352 | fput(bprm->file); | |
1353 | } | |
1da177e4 | 1354 | out_kfree: |
08a6fac1 | 1355 | free_bprm(bprm); |
1da177e4 | 1356 | |
fd8328be | 1357 | out_files: |
3b125388 AV |
1358 | if (displaced) |
1359 | reset_files_struct(displaced); | |
1da177e4 LT |
1360 | out_ret: |
1361 | return retval; | |
1362 | } | |
1363 | ||
1364 | int set_binfmt(struct linux_binfmt *new) | |
1365 | { | |
1366 | struct linux_binfmt *old = current->binfmt; | |
1367 | ||
1368 | if (new) { | |
1369 | if (!try_module_get(new->module)) | |
1370 | return -1; | |
1371 | } | |
1372 | current->binfmt = new; | |
1373 | if (old) | |
1374 | module_put(old->module); | |
1375 | return 0; | |
1376 | } | |
1377 | ||
1378 | EXPORT_SYMBOL(set_binfmt); | |
1379 | ||
1da177e4 LT |
1380 | /* format_corename will inspect the pattern parameter, and output a |
1381 | * name into corename, which must have space for at least | |
1382 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1383 | */ | |
c4bbafda | 1384 | static int format_corename(char *corename, const char *pattern, long signr) |
1da177e4 LT |
1385 | { |
1386 | const char *pat_ptr = pattern; | |
1387 | char *out_ptr = corename; | |
1388 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1389 | int rc; | |
1390 | int pid_in_pattern = 0; | |
c4bbafda AC |
1391 | int ispipe = 0; |
1392 | ||
1393 | if (*pattern == '|') | |
1394 | ispipe = 1; | |
1da177e4 LT |
1395 | |
1396 | /* Repeat as long as we have more pattern to process and more output | |
1397 | space */ | |
1398 | while (*pat_ptr) { | |
1399 | if (*pat_ptr != '%') { | |
1400 | if (out_ptr == out_end) | |
1401 | goto out; | |
1402 | *out_ptr++ = *pat_ptr++; | |
1403 | } else { | |
1404 | switch (*++pat_ptr) { | |
1405 | case 0: | |
1406 | goto out; | |
1407 | /* Double percent, output one percent */ | |
1408 | case '%': | |
1409 | if (out_ptr == out_end) | |
1410 | goto out; | |
1411 | *out_ptr++ = '%'; | |
1412 | break; | |
1413 | /* pid */ | |
1414 | case 'p': | |
1415 | pid_in_pattern = 1; | |
1416 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1417 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1418 | if (rc > out_end - out_ptr) |
1419 | goto out; | |
1420 | out_ptr += rc; | |
1421 | break; | |
1422 | /* uid */ | |
1423 | case 'u': | |
1424 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1425 | "%d", current->uid); | |
1426 | if (rc > out_end - out_ptr) | |
1427 | goto out; | |
1428 | out_ptr += rc; | |
1429 | break; | |
1430 | /* gid */ | |
1431 | case 'g': | |
1432 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1433 | "%d", current->gid); | |
1434 | if (rc > out_end - out_ptr) | |
1435 | goto out; | |
1436 | out_ptr += rc; | |
1437 | break; | |
1438 | /* signal that caused the coredump */ | |
1439 | case 's': | |
1440 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1441 | "%ld", signr); | |
1442 | if (rc > out_end - out_ptr) | |
1443 | goto out; | |
1444 | out_ptr += rc; | |
1445 | break; | |
1446 | /* UNIX time of coredump */ | |
1447 | case 't': { | |
1448 | struct timeval tv; | |
1449 | do_gettimeofday(&tv); | |
1450 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1451 | "%lu", tv.tv_sec); | |
1452 | if (rc > out_end - out_ptr) | |
1453 | goto out; | |
1454 | out_ptr += rc; | |
1455 | break; | |
1456 | } | |
1457 | /* hostname */ | |
1458 | case 'h': | |
1459 | down_read(&uts_sem); | |
1460 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1461 | "%s", utsname()->nodename); |
1da177e4 LT |
1462 | up_read(&uts_sem); |
1463 | if (rc > out_end - out_ptr) | |
1464 | goto out; | |
1465 | out_ptr += rc; | |
1466 | break; | |
1467 | /* executable */ | |
1468 | case 'e': | |
1469 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1470 | "%s", current->comm); | |
1471 | if (rc > out_end - out_ptr) | |
1472 | goto out; | |
1473 | out_ptr += rc; | |
1474 | break; | |
74aadce9 NH |
1475 | /* core limit size */ |
1476 | case 'c': | |
1477 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1478 | "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); | |
1479 | if (rc > out_end - out_ptr) | |
1480 | goto out; | |
1481 | out_ptr += rc; | |
1482 | break; | |
1da177e4 LT |
1483 | default: |
1484 | break; | |
1485 | } | |
1486 | ++pat_ptr; | |
1487 | } | |
1488 | } | |
1489 | /* Backward compatibility with core_uses_pid: | |
1490 | * | |
1491 | * If core_pattern does not include a %p (as is the default) | |
1492 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda AC |
1493 | * the filename. Do not do this for piped commands. */ |
1494 | if (!ispipe && !pid_in_pattern | |
1da177e4 LT |
1495 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { |
1496 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1497 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1498 | if (rc > out_end - out_ptr) |
1499 | goto out; | |
1500 | out_ptr += rc; | |
1501 | } | |
c4bbafda | 1502 | out: |
1da177e4 | 1503 | *out_ptr = 0; |
c4bbafda | 1504 | return ispipe; |
1da177e4 LT |
1505 | } |
1506 | ||
d5f70c00 | 1507 | static void zap_process(struct task_struct *start) |
aceecc04 ON |
1508 | { |
1509 | struct task_struct *t; | |
281de339 | 1510 | |
d5f70c00 ON |
1511 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1512 | start->signal->group_stop_count = 0; | |
aceecc04 ON |
1513 | |
1514 | t = start; | |
1515 | do { | |
1516 | if (t != current && t->mm) { | |
1517 | t->mm->core_waiters++; | |
281de339 ON |
1518 | sigaddset(&t->pending.signal, SIGKILL); |
1519 | signal_wake_up(t, 1); | |
aceecc04 | 1520 | } |
e4901f92 | 1521 | } while_each_thread(start, t); |
aceecc04 ON |
1522 | } |
1523 | ||
dcf560c5 ON |
1524 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
1525 | int exit_code) | |
1da177e4 LT |
1526 | { |
1527 | struct task_struct *g, *p; | |
5debfa6d | 1528 | unsigned long flags; |
dcf560c5 ON |
1529 | int err = -EAGAIN; |
1530 | ||
1531 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1532 | if (!signal_group_exit(tsk->signal)) { |
dcf560c5 | 1533 | tsk->signal->group_exit_code = exit_code; |
5debfa6d | 1534 | zap_process(tsk); |
dcf560c5 | 1535 | err = 0; |
1da177e4 | 1536 | } |
dcf560c5 ON |
1537 | spin_unlock_irq(&tsk->sighand->siglock); |
1538 | if (err) | |
1539 | return err; | |
1da177e4 | 1540 | |
5debfa6d ON |
1541 | if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) |
1542 | goto done; | |
e4901f92 ON |
1543 | /* |
1544 | * We should find and kill all tasks which use this mm, and we should | |
1545 | * count them correctly into mm->core_waiters. We don't take tasklist | |
1546 | * lock, but this is safe wrt: | |
1547 | * | |
1548 | * fork: | |
1549 | * None of sub-threads can fork after zap_process(leader). All | |
1550 | * processes which were created before this point should be | |
1551 | * visible to zap_threads() because copy_process() adds the new | |
1552 | * process to the tail of init_task.tasks list, and lock/unlock | |
1553 | * of ->siglock provides a memory barrier. | |
1554 | * | |
1555 | * do_exit: | |
1556 | * The caller holds mm->mmap_sem. This means that the task which | |
1557 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1558 | * its ->mm. | |
1559 | * | |
1560 | * de_thread: | |
1561 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1562 | * we must see either old or new leader, this does not matter. | |
1563 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1564 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1565 | * it can't fail. | |
1566 | * | |
1567 | * Note also that "g" can be the old leader with ->mm == NULL | |
1568 | * and already unhashed and thus removed from ->thread_group. | |
1569 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1570 | * clear the ->next pointer, we will find the new leader via | |
1571 | * next_thread(). | |
1572 | */ | |
7b1c6154 | 1573 | rcu_read_lock(); |
aceecc04 | 1574 | for_each_process(g) { |
5debfa6d ON |
1575 | if (g == tsk->group_leader) |
1576 | continue; | |
1577 | ||
aceecc04 ON |
1578 | p = g; |
1579 | do { | |
1580 | if (p->mm) { | |
5debfa6d | 1581 | if (p->mm == mm) { |
5debfa6d | 1582 | lock_task_sighand(p, &flags); |
d5f70c00 | 1583 | zap_process(p); |
5debfa6d ON |
1584 | unlock_task_sighand(p, &flags); |
1585 | } | |
aceecc04 ON |
1586 | break; |
1587 | } | |
e4901f92 | 1588 | } while_each_thread(g, p); |
aceecc04 | 1589 | } |
7b1c6154 | 1590 | rcu_read_unlock(); |
5debfa6d | 1591 | done: |
dcf560c5 | 1592 | return mm->core_waiters; |
1da177e4 LT |
1593 | } |
1594 | ||
dcf560c5 | 1595 | static int coredump_wait(int exit_code) |
1da177e4 | 1596 | { |
dcf560c5 ON |
1597 | struct task_struct *tsk = current; |
1598 | struct mm_struct *mm = tsk->mm; | |
1599 | struct completion startup_done; | |
1600 | struct completion *vfork_done; | |
2384f55f | 1601 | int core_waiters; |
1da177e4 | 1602 | |
dcf560c5 ON |
1603 | init_completion(&mm->core_done); |
1604 | init_completion(&startup_done); | |
1da177e4 LT |
1605 | mm->core_startup_done = &startup_done; |
1606 | ||
dcf560c5 | 1607 | core_waiters = zap_threads(tsk, mm, exit_code); |
2384f55f ON |
1608 | up_write(&mm->mmap_sem); |
1609 | ||
dcf560c5 ON |
1610 | if (unlikely(core_waiters < 0)) |
1611 | goto fail; | |
1612 | ||
1613 | /* | |
1614 | * Make sure nobody is waiting for us to release the VM, | |
1615 | * otherwise we can deadlock when we wait on each other | |
1616 | */ | |
1617 | vfork_done = tsk->vfork_done; | |
1618 | if (vfork_done) { | |
1619 | tsk->vfork_done = NULL; | |
1620 | complete(vfork_done); | |
1621 | } | |
1622 | ||
2384f55f | 1623 | if (core_waiters) |
1da177e4 | 1624 | wait_for_completion(&startup_done); |
dcf560c5 | 1625 | fail: |
1da177e4 | 1626 | BUG_ON(mm->core_waiters); |
dcf560c5 | 1627 | return core_waiters; |
1da177e4 LT |
1628 | } |
1629 | ||
6c5d5238 KH |
1630 | /* |
1631 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1632 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1633 | * these bits are not changed atomically. So get_dumpable can observe the | |
1634 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1635 | * return either old dumpable or new one by paying attention to the order of | |
1636 | * modifying the bits. | |
1637 | * | |
1638 | * dumpable | mm->flags (binary) | |
1639 | * old new | initial interim final | |
1640 | * ---------+----------------------- | |
1641 | * 0 1 | 00 01 01 | |
1642 | * 0 2 | 00 10(*) 11 | |
1643 | * 1 0 | 01 00 00 | |
1644 | * 1 2 | 01 11 11 | |
1645 | * 2 0 | 11 10(*) 00 | |
1646 | * 2 1 | 11 11 01 | |
1647 | * | |
1648 | * (*) get_dumpable regards interim value of 10 as 11. | |
1649 | */ | |
1650 | void set_dumpable(struct mm_struct *mm, int value) | |
1651 | { | |
1652 | switch (value) { | |
1653 | case 0: | |
1654 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1655 | smp_wmb(); | |
1656 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1657 | break; | |
1658 | case 1: | |
1659 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1660 | smp_wmb(); | |
1661 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1662 | break; | |
1663 | case 2: | |
1664 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1665 | smp_wmb(); | |
1666 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1667 | break; | |
1668 | } | |
1669 | } | |
6c5d5238 KH |
1670 | |
1671 | int get_dumpable(struct mm_struct *mm) | |
1672 | { | |
1673 | int ret; | |
1674 | ||
1675 | ret = mm->flags & 0x3; | |
1676 | return (ret >= 2) ? 2 : ret; | |
1677 | } | |
1678 | ||
1da177e4 LT |
1679 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) |
1680 | { | |
1681 | char corename[CORENAME_MAX_SIZE + 1]; | |
1682 | struct mm_struct *mm = current->mm; | |
1683 | struct linux_binfmt * binfmt; | |
1684 | struct inode * inode; | |
1685 | struct file * file; | |
1686 | int retval = 0; | |
d6e71144 AC |
1687 | int fsuid = current->fsuid; |
1688 | int flag = 0; | |
d025c9db | 1689 | int ispipe = 0; |
7dc0b22e | 1690 | unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; |
74aadce9 NH |
1691 | char **helper_argv = NULL; |
1692 | int helper_argc = 0; | |
1693 | char *delimit; | |
1da177e4 | 1694 | |
0a4ff8c2 SG |
1695 | audit_core_dumps(signr); |
1696 | ||
1da177e4 LT |
1697 | binfmt = current->binfmt; |
1698 | if (!binfmt || !binfmt->core_dump) | |
1699 | goto fail; | |
1700 | down_write(&mm->mmap_sem); | |
00ec99da RM |
1701 | /* |
1702 | * If another thread got here first, or we are not dumpable, bail out. | |
1703 | */ | |
1704 | if (mm->core_waiters || !get_dumpable(mm)) { | |
1da177e4 LT |
1705 | up_write(&mm->mmap_sem); |
1706 | goto fail; | |
1707 | } | |
d6e71144 AC |
1708 | |
1709 | /* | |
1710 | * We cannot trust fsuid as being the "true" uid of the | |
1711 | * process nor do we know its entire history. We only know it | |
1712 | * was tainted so we dump it as root in mode 2. | |
1713 | */ | |
6c5d5238 | 1714 | if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ |
d6e71144 AC |
1715 | flag = O_EXCL; /* Stop rewrite attacks */ |
1716 | current->fsuid = 0; /* Dump root private */ | |
1717 | } | |
1291cf41 | 1718 | |
dcf560c5 ON |
1719 | retval = coredump_wait(exit_code); |
1720 | if (retval < 0) | |
1291cf41 | 1721 | goto fail; |
1da177e4 LT |
1722 | |
1723 | /* | |
1724 | * Clear any false indication of pending signals that might | |
1725 | * be seen by the filesystem code called to write the core file. | |
1726 | */ | |
1da177e4 LT |
1727 | clear_thread_flag(TIF_SIGPENDING); |
1728 | ||
1da177e4 LT |
1729 | /* |
1730 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1731 | * uses lock_kernel() | |
1732 | */ | |
1733 | lock_kernel(); | |
c4bbafda | 1734 | ispipe = format_corename(corename, core_pattern, signr); |
1da177e4 | 1735 | unlock_kernel(); |
7dc0b22e NH |
1736 | /* |
1737 | * Don't bother to check the RLIMIT_CORE value if core_pattern points | |
1738 | * to a pipe. Since we're not writing directly to the filesystem | |
1739 | * RLIMIT_CORE doesn't really apply, as no actual core file will be | |
1740 | * created unless the pipe reader choses to write out the core file | |
1741 | * at which point file size limits and permissions will be imposed | |
1742 | * as it does with any other process | |
1743 | */ | |
74aadce9 | 1744 | if ((!ispipe) && (core_limit < binfmt->min_coredump)) |
7dc0b22e NH |
1745 | goto fail_unlock; |
1746 | ||
c4bbafda | 1747 | if (ispipe) { |
74aadce9 NH |
1748 | helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc); |
1749 | /* Terminate the string before the first option */ | |
1750 | delimit = strchr(corename, ' '); | |
1751 | if (delimit) | |
1752 | *delimit = '\0'; | |
32321137 NH |
1753 | delimit = strrchr(helper_argv[0], '/'); |
1754 | if (delimit) | |
1755 | delimit++; | |
1756 | else | |
1757 | delimit = helper_argv[0]; | |
1758 | if (!strcmp(delimit, current->comm)) { | |
1759 | printk(KERN_NOTICE "Recursive core dump detected, " | |
1760 | "aborting\n"); | |
1761 | goto fail_unlock; | |
1762 | } | |
1763 | ||
1764 | core_limit = RLIM_INFINITY; | |
1765 | ||
d025c9db | 1766 | /* SIGPIPE can happen, but it's just never processed */ |
32321137 NH |
1767 | if (call_usermodehelper_pipe(corename+1, helper_argv, NULL, |
1768 | &file)) { | |
d025c9db AK |
1769 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1770 | corename); | |
1771 | goto fail_unlock; | |
1772 | } | |
d025c9db AK |
1773 | } else |
1774 | file = filp_open(corename, | |
6d4df677 AD |
1775 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1776 | 0600); | |
1da177e4 LT |
1777 | if (IS_ERR(file)) |
1778 | goto fail_unlock; | |
0f7fc9e4 | 1779 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1780 | if (inode->i_nlink > 1) |
1781 | goto close_fail; /* multiple links - don't dump */ | |
0f7fc9e4 | 1782 | if (!ispipe && d_unhashed(file->f_path.dentry)) |
1da177e4 LT |
1783 | goto close_fail; |
1784 | ||
d025c9db AK |
1785 | /* AK: actually i see no reason to not allow this for named pipes etc., |
1786 | but keep the previous behaviour for now. */ | |
1787 | if (!ispipe && !S_ISREG(inode->i_mode)) | |
1da177e4 | 1788 | goto close_fail; |
c46f739d IM |
1789 | /* |
1790 | * Dont allow local users get cute and trick others to coredump | |
1791 | * into their pre-created files: | |
1792 | */ | |
1793 | if (inode->i_uid != current->fsuid) | |
1794 | goto close_fail; | |
1da177e4 LT |
1795 | if (!file->f_op) |
1796 | goto close_fail; | |
1797 | if (!file->f_op->write) | |
1798 | goto close_fail; | |
0f7fc9e4 | 1799 | if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) |
1da177e4 LT |
1800 | goto close_fail; |
1801 | ||
7dc0b22e | 1802 | retval = binfmt->core_dump(signr, regs, file, core_limit); |
1da177e4 LT |
1803 | |
1804 | if (retval) | |
1805 | current->signal->group_exit_code |= 0x80; | |
1806 | close_fail: | |
1807 | filp_close(file, NULL); | |
1808 | fail_unlock: | |
74aadce9 NH |
1809 | if (helper_argv) |
1810 | argv_free(helper_argv); | |
1811 | ||
d6e71144 | 1812 | current->fsuid = fsuid; |
1da177e4 LT |
1813 | complete_all(&mm->core_done); |
1814 | fail: | |
1815 | return retval; | |
1816 | } |