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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 | ||
25 | #include <linux/config.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/file.h> | |
28 | #include <linux/mman.h> | |
29 | #include <linux/a.out.h> | |
30 | #include <linux/stat.h> | |
31 | #include <linux/fcntl.h> | |
32 | #include <linux/smp_lock.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/pagemap.h> | |
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> | |
40 | #include <linux/swap.h> | |
41 | #include <linux/utsname.h> | |
42 | #include <linux/module.h> | |
43 | #include <linux/namei.h> | |
44 | #include <linux/proc_fs.h> | |
45 | #include <linux/ptrace.h> | |
46 | #include <linux/mount.h> | |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
49 | #include <linux/rmap.h> | |
50 | #include <linux/acct.h> | |
51 | ||
52 | #include <asm/uaccess.h> | |
53 | #include <asm/mmu_context.h> | |
54 | ||
55 | #ifdef CONFIG_KMOD | |
56 | #include <linux/kmod.h> | |
57 | #endif | |
58 | ||
59 | int core_uses_pid; | |
60 | char core_pattern[65] = "core"; | |
d6e71144 AC |
61 | int suid_dumpable = 0; |
62 | ||
63 | EXPORT_SYMBOL(suid_dumpable); | |
1da177e4 LT |
64 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
65 | ||
66 | static struct linux_binfmt *formats; | |
67 | static DEFINE_RWLOCK(binfmt_lock); | |
68 | ||
69 | int register_binfmt(struct linux_binfmt * fmt) | |
70 | { | |
71 | struct linux_binfmt ** tmp = &formats; | |
72 | ||
73 | if (!fmt) | |
74 | return -EINVAL; | |
75 | if (fmt->next) | |
76 | return -EBUSY; | |
77 | write_lock(&binfmt_lock); | |
78 | while (*tmp) { | |
79 | if (fmt == *tmp) { | |
80 | write_unlock(&binfmt_lock); | |
81 | return -EBUSY; | |
82 | } | |
83 | tmp = &(*tmp)->next; | |
84 | } | |
85 | fmt->next = formats; | |
86 | formats = fmt; | |
87 | write_unlock(&binfmt_lock); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | EXPORT_SYMBOL(register_binfmt); | |
92 | ||
93 | int unregister_binfmt(struct linux_binfmt * fmt) | |
94 | { | |
95 | struct linux_binfmt ** tmp = &formats; | |
96 | ||
97 | write_lock(&binfmt_lock); | |
98 | while (*tmp) { | |
99 | if (fmt == *tmp) { | |
100 | *tmp = fmt->next; | |
101 | write_unlock(&binfmt_lock); | |
102 | return 0; | |
103 | } | |
104 | tmp = &(*tmp)->next; | |
105 | } | |
106 | write_unlock(&binfmt_lock); | |
107 | return -EINVAL; | |
108 | } | |
109 | ||
110 | EXPORT_SYMBOL(unregister_binfmt); | |
111 | ||
112 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
113 | { | |
114 | module_put(fmt->module); | |
115 | } | |
116 | ||
117 | /* | |
118 | * Note that a shared library must be both readable and executable due to | |
119 | * security reasons. | |
120 | * | |
121 | * Also note that we take the address to load from from the file itself. | |
122 | */ | |
123 | asmlinkage long sys_uselib(const char __user * library) | |
124 | { | |
125 | struct file * file; | |
126 | struct nameidata nd; | |
127 | int error; | |
128 | ||
834f2a4a | 129 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ); |
1da177e4 LT |
130 | if (error) |
131 | goto out; | |
132 | ||
133 | error = -EINVAL; | |
134 | if (!S_ISREG(nd.dentry->d_inode->i_mode)) | |
135 | goto exit; | |
136 | ||
137 | error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd); | |
138 | if (error) | |
139 | goto exit; | |
140 | ||
834f2a4a | 141 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
142 | error = PTR_ERR(file); |
143 | if (IS_ERR(file)) | |
144 | goto out; | |
145 | ||
146 | error = -ENOEXEC; | |
147 | if(file->f_op) { | |
148 | struct linux_binfmt * fmt; | |
149 | ||
150 | read_lock(&binfmt_lock); | |
151 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
152 | if (!fmt->load_shlib) | |
153 | continue; | |
154 | if (!try_module_get(fmt->module)) | |
155 | continue; | |
156 | read_unlock(&binfmt_lock); | |
157 | error = fmt->load_shlib(file); | |
158 | read_lock(&binfmt_lock); | |
159 | put_binfmt(fmt); | |
160 | if (error != -ENOEXEC) | |
161 | break; | |
162 | } | |
163 | read_unlock(&binfmt_lock); | |
164 | } | |
165 | fput(file); | |
166 | out: | |
167 | return error; | |
168 | exit: | |
834f2a4a | 169 | release_open_intent(&nd); |
1da177e4 LT |
170 | path_release(&nd); |
171 | goto out; | |
172 | } | |
173 | ||
174 | /* | |
175 | * count() counts the number of strings in array ARGV. | |
176 | */ | |
177 | static int count(char __user * __user * argv, int max) | |
178 | { | |
179 | int i = 0; | |
180 | ||
181 | if (argv != NULL) { | |
182 | for (;;) { | |
183 | char __user * p; | |
184 | ||
185 | if (get_user(p, argv)) | |
186 | return -EFAULT; | |
187 | if (!p) | |
188 | break; | |
189 | argv++; | |
190 | if(++i > max) | |
191 | return -E2BIG; | |
192 | cond_resched(); | |
193 | } | |
194 | } | |
195 | return i; | |
196 | } | |
197 | ||
198 | /* | |
199 | * 'copy_strings()' copies argument/environment strings from user | |
200 | * memory to free pages in kernel mem. These are in a format ready | |
201 | * to be put directly into the top of new user memory. | |
202 | */ | |
75c96f85 AB |
203 | static int copy_strings(int argc, char __user * __user * argv, |
204 | struct linux_binprm *bprm) | |
1da177e4 LT |
205 | { |
206 | struct page *kmapped_page = NULL; | |
207 | char *kaddr = NULL; | |
208 | int ret; | |
209 | ||
210 | while (argc-- > 0) { | |
211 | char __user *str; | |
212 | int len; | |
213 | unsigned long pos; | |
214 | ||
215 | if (get_user(str, argv+argc) || | |
216 | !(len = strnlen_user(str, bprm->p))) { | |
217 | ret = -EFAULT; | |
218 | goto out; | |
219 | } | |
220 | ||
221 | if (bprm->p < len) { | |
222 | ret = -E2BIG; | |
223 | goto out; | |
224 | } | |
225 | ||
226 | bprm->p -= len; | |
227 | /* XXX: add architecture specific overflow check here. */ | |
228 | pos = bprm->p; | |
229 | ||
230 | while (len > 0) { | |
231 | int i, new, err; | |
232 | int offset, bytes_to_copy; | |
233 | struct page *page; | |
234 | ||
235 | offset = pos % PAGE_SIZE; | |
236 | i = pos/PAGE_SIZE; | |
237 | page = bprm->page[i]; | |
238 | new = 0; | |
239 | if (!page) { | |
240 | page = alloc_page(GFP_HIGHUSER); | |
241 | bprm->page[i] = page; | |
242 | if (!page) { | |
243 | ret = -ENOMEM; | |
244 | goto out; | |
245 | } | |
246 | new = 1; | |
247 | } | |
248 | ||
249 | if (page != kmapped_page) { | |
250 | if (kmapped_page) | |
251 | kunmap(kmapped_page); | |
252 | kmapped_page = page; | |
253 | kaddr = kmap(kmapped_page); | |
254 | } | |
255 | if (new && offset) | |
256 | memset(kaddr, 0, offset); | |
257 | bytes_to_copy = PAGE_SIZE - offset; | |
258 | if (bytes_to_copy > len) { | |
259 | bytes_to_copy = len; | |
260 | if (new) | |
261 | memset(kaddr+offset+len, 0, | |
262 | PAGE_SIZE-offset-len); | |
263 | } | |
264 | err = copy_from_user(kaddr+offset, str, bytes_to_copy); | |
265 | if (err) { | |
266 | ret = -EFAULT; | |
267 | goto out; | |
268 | } | |
269 | ||
270 | pos += bytes_to_copy; | |
271 | str += bytes_to_copy; | |
272 | len -= bytes_to_copy; | |
273 | } | |
274 | } | |
275 | ret = 0; | |
276 | out: | |
277 | if (kmapped_page) | |
278 | kunmap(kmapped_page); | |
279 | return ret; | |
280 | } | |
281 | ||
282 | /* | |
283 | * Like copy_strings, but get argv and its values from kernel memory. | |
284 | */ | |
285 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
286 | { | |
287 | int r; | |
288 | mm_segment_t oldfs = get_fs(); | |
289 | set_fs(KERNEL_DS); | |
290 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
291 | set_fs(oldfs); | |
292 | return r; | |
293 | } | |
294 | ||
295 | EXPORT_SYMBOL(copy_strings_kernel); | |
296 | ||
297 | #ifdef CONFIG_MMU | |
298 | /* | |
299 | * This routine is used to map in a page into an address space: needed by | |
300 | * execve() for the initial stack and environment pages. | |
301 | * | |
302 | * vma->vm_mm->mmap_sem is held for writing. | |
303 | */ | |
304 | void install_arg_page(struct vm_area_struct *vma, | |
305 | struct page *page, unsigned long address) | |
306 | { | |
307 | struct mm_struct *mm = vma->vm_mm; | |
308 | pgd_t * pgd; | |
309 | pud_t * pud; | |
310 | pmd_t * pmd; | |
311 | pte_t * pte; | |
c74df32c | 312 | spinlock_t *ptl; |
1da177e4 LT |
313 | |
314 | if (unlikely(anon_vma_prepare(vma))) | |
c74df32c | 315 | goto out; |
1da177e4 LT |
316 | |
317 | flush_dcache_page(page); | |
318 | pgd = pgd_offset(mm, address); | |
1da177e4 LT |
319 | pud = pud_alloc(mm, pgd, address); |
320 | if (!pud) | |
321 | goto out; | |
322 | pmd = pmd_alloc(mm, pud, address); | |
323 | if (!pmd) | |
324 | goto out; | |
c74df32c | 325 | pte = pte_alloc_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
326 | if (!pte) |
327 | goto out; | |
328 | if (!pte_none(*pte)) { | |
c74df32c | 329 | pte_unmap_unlock(pte, ptl); |
1da177e4 LT |
330 | goto out; |
331 | } | |
4294621f | 332 | inc_mm_counter(mm, anon_rss); |
1da177e4 LT |
333 | lru_cache_add_active(page); |
334 | set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte( | |
335 | page, vma->vm_page_prot)))); | |
336 | page_add_anon_rmap(page, vma, address); | |
c74df32c | 337 | pte_unmap_unlock(pte, ptl); |
1da177e4 LT |
338 | |
339 | /* no need for flush_tlb */ | |
340 | return; | |
341 | out: | |
1da177e4 LT |
342 | __free_page(page); |
343 | force_sig(SIGKILL, current); | |
344 | } | |
345 | ||
346 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
347 | ||
348 | int setup_arg_pages(struct linux_binprm *bprm, | |
349 | unsigned long stack_top, | |
350 | int executable_stack) | |
351 | { | |
352 | unsigned long stack_base; | |
353 | struct vm_area_struct *mpnt; | |
354 | struct mm_struct *mm = current->mm; | |
355 | int i, ret; | |
356 | long arg_size; | |
357 | ||
358 | #ifdef CONFIG_STACK_GROWSUP | |
359 | /* Move the argument and environment strings to the bottom of the | |
360 | * stack space. | |
361 | */ | |
362 | int offset, j; | |
363 | char *to, *from; | |
364 | ||
365 | /* Start by shifting all the pages down */ | |
366 | i = 0; | |
367 | for (j = 0; j < MAX_ARG_PAGES; j++) { | |
368 | struct page *page = bprm->page[j]; | |
369 | if (!page) | |
370 | continue; | |
371 | bprm->page[i++] = page; | |
372 | } | |
373 | ||
374 | /* Now move them within their pages */ | |
375 | offset = bprm->p % PAGE_SIZE; | |
376 | to = kmap(bprm->page[0]); | |
377 | for (j = 1; j < i; j++) { | |
378 | memmove(to, to + offset, PAGE_SIZE - offset); | |
379 | from = kmap(bprm->page[j]); | |
380 | memcpy(to + PAGE_SIZE - offset, from, offset); | |
381 | kunmap(bprm->page[j - 1]); | |
382 | to = from; | |
383 | } | |
384 | memmove(to, to + offset, PAGE_SIZE - offset); | |
385 | kunmap(bprm->page[j - 1]); | |
386 | ||
387 | /* Limit stack size to 1GB */ | |
388 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
389 | if (stack_base > (1 << 30)) | |
390 | stack_base = 1 << 30; | |
391 | stack_base = PAGE_ALIGN(stack_top - stack_base); | |
392 | ||
393 | /* Adjust bprm->p to point to the end of the strings. */ | |
394 | bprm->p = stack_base + PAGE_SIZE * i - offset; | |
395 | ||
396 | mm->arg_start = stack_base; | |
397 | arg_size = i << PAGE_SHIFT; | |
398 | ||
399 | /* zero pages that were copied above */ | |
400 | while (i < MAX_ARG_PAGES) | |
401 | bprm->page[i++] = NULL; | |
402 | #else | |
403 | stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE); | |
404 | stack_base = PAGE_ALIGN(stack_base); | |
405 | bprm->p += stack_base; | |
406 | mm->arg_start = bprm->p; | |
407 | arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start); | |
408 | #endif | |
409 | ||
410 | arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
411 | ||
412 | if (bprm->loader) | |
413 | bprm->loader += stack_base; | |
414 | bprm->exec += stack_base; | |
415 | ||
416 | mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
417 | if (!mpnt) | |
418 | return -ENOMEM; | |
419 | ||
1da177e4 LT |
420 | memset(mpnt, 0, sizeof(*mpnt)); |
421 | ||
422 | down_write(&mm->mmap_sem); | |
423 | { | |
424 | mpnt->vm_mm = mm; | |
425 | #ifdef CONFIG_STACK_GROWSUP | |
426 | mpnt->vm_start = stack_base; | |
427 | mpnt->vm_end = stack_base + arg_size; | |
428 | #else | |
429 | mpnt->vm_end = stack_top; | |
430 | mpnt->vm_start = mpnt->vm_end - arg_size; | |
431 | #endif | |
432 | /* Adjust stack execute permissions; explicitly enable | |
433 | * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X | |
434 | * and leave alone (arch default) otherwise. */ | |
435 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
436 | mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC; | |
437 | else if (executable_stack == EXSTACK_DISABLE_X) | |
438 | mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC; | |
439 | else | |
440 | mpnt->vm_flags = VM_STACK_FLAGS; | |
441 | mpnt->vm_flags |= mm->def_flags; | |
442 | mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7]; | |
443 | if ((ret = insert_vm_struct(mm, mpnt))) { | |
444 | up_write(&mm->mmap_sem); | |
445 | kmem_cache_free(vm_area_cachep, mpnt); | |
446 | return ret; | |
447 | } | |
448 | mm->stack_vm = mm->total_vm = vma_pages(mpnt); | |
449 | } | |
450 | ||
451 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) { | |
452 | struct page *page = bprm->page[i]; | |
453 | if (page) { | |
454 | bprm->page[i] = NULL; | |
455 | install_arg_page(mpnt, page, stack_base); | |
456 | } | |
457 | stack_base += PAGE_SIZE; | |
458 | } | |
459 | up_write(&mm->mmap_sem); | |
460 | ||
461 | return 0; | |
462 | } | |
463 | ||
464 | EXPORT_SYMBOL(setup_arg_pages); | |
465 | ||
466 | #define free_arg_pages(bprm) do { } while (0) | |
467 | ||
468 | #else | |
469 | ||
470 | static inline void free_arg_pages(struct linux_binprm *bprm) | |
471 | { | |
472 | int i; | |
473 | ||
474 | for (i = 0; i < MAX_ARG_PAGES; i++) { | |
475 | if (bprm->page[i]) | |
476 | __free_page(bprm->page[i]); | |
477 | bprm->page[i] = NULL; | |
478 | } | |
479 | } | |
480 | ||
481 | #endif /* CONFIG_MMU */ | |
482 | ||
483 | struct file *open_exec(const char *name) | |
484 | { | |
485 | struct nameidata nd; | |
486 | int err; | |
487 | struct file *file; | |
488 | ||
834f2a4a | 489 | err = path_lookup_open(name, LOOKUP_FOLLOW, &nd, FMODE_READ); |
1da177e4 LT |
490 | file = ERR_PTR(err); |
491 | ||
492 | if (!err) { | |
493 | struct inode *inode = nd.dentry->d_inode; | |
494 | file = ERR_PTR(-EACCES); | |
495 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && | |
496 | S_ISREG(inode->i_mode)) { | |
497 | int err = permission(inode, MAY_EXEC, &nd); | |
498 | if (!err && !(inode->i_mode & 0111)) | |
499 | err = -EACCES; | |
500 | file = ERR_PTR(err); | |
501 | if (!err) { | |
834f2a4a | 502 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
503 | if (!IS_ERR(file)) { |
504 | err = deny_write_access(file); | |
505 | if (err) { | |
506 | fput(file); | |
507 | file = ERR_PTR(err); | |
508 | } | |
509 | } | |
510 | out: | |
511 | return file; | |
512 | } | |
513 | } | |
834f2a4a | 514 | release_open_intent(&nd); |
1da177e4 LT |
515 | path_release(&nd); |
516 | } | |
517 | goto out; | |
518 | } | |
519 | ||
520 | EXPORT_SYMBOL(open_exec); | |
521 | ||
522 | int kernel_read(struct file *file, unsigned long offset, | |
523 | char *addr, unsigned long count) | |
524 | { | |
525 | mm_segment_t old_fs; | |
526 | loff_t pos = offset; | |
527 | int result; | |
528 | ||
529 | old_fs = get_fs(); | |
530 | set_fs(get_ds()); | |
531 | /* The cast to a user pointer is valid due to the set_fs() */ | |
532 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
533 | set_fs(old_fs); | |
534 | return result; | |
535 | } | |
536 | ||
537 | EXPORT_SYMBOL(kernel_read); | |
538 | ||
539 | static int exec_mmap(struct mm_struct *mm) | |
540 | { | |
541 | struct task_struct *tsk; | |
542 | struct mm_struct * old_mm, *active_mm; | |
543 | ||
544 | /* Notify parent that we're no longer interested in the old VM */ | |
545 | tsk = current; | |
546 | old_mm = current->mm; | |
547 | mm_release(tsk, old_mm); | |
548 | ||
549 | if (old_mm) { | |
550 | /* | |
551 | * Make sure that if there is a core dump in progress | |
552 | * for the old mm, we get out and die instead of going | |
553 | * through with the exec. We must hold mmap_sem around | |
554 | * checking core_waiters and changing tsk->mm. The | |
555 | * core-inducing thread will increment core_waiters for | |
556 | * each thread whose ->mm == old_mm. | |
557 | */ | |
558 | down_read(&old_mm->mmap_sem); | |
559 | if (unlikely(old_mm->core_waiters)) { | |
560 | up_read(&old_mm->mmap_sem); | |
561 | return -EINTR; | |
562 | } | |
563 | } | |
564 | task_lock(tsk); | |
565 | active_mm = tsk->active_mm; | |
566 | tsk->mm = mm; | |
567 | tsk->active_mm = mm; | |
568 | activate_mm(active_mm, mm); | |
569 | task_unlock(tsk); | |
570 | arch_pick_mmap_layout(mm); | |
571 | if (old_mm) { | |
572 | up_read(&old_mm->mmap_sem); | |
573 | if (active_mm != old_mm) BUG(); | |
574 | mmput(old_mm); | |
575 | return 0; | |
576 | } | |
577 | mmdrop(active_mm); | |
578 | return 0; | |
579 | } | |
580 | ||
581 | /* | |
582 | * This function makes sure the current process has its own signal table, | |
583 | * so that flush_signal_handlers can later reset the handlers without | |
584 | * disturbing other processes. (Other processes might share the signal | |
585 | * table via the CLONE_SIGHAND option to clone().) | |
586 | */ | |
587 | static inline int de_thread(struct task_struct *tsk) | |
588 | { | |
589 | struct signal_struct *sig = tsk->signal; | |
590 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand; | |
591 | spinlock_t *lock = &oldsighand->siglock; | |
592 | int count; | |
593 | ||
594 | /* | |
595 | * If we don't share sighandlers, then we aren't sharing anything | |
596 | * and we can just re-use it all. | |
597 | */ | |
598 | if (atomic_read(&oldsighand->count) <= 1) { | |
599 | BUG_ON(atomic_read(&sig->count) != 1); | |
600 | exit_itimers(sig); | |
601 | return 0; | |
602 | } | |
603 | ||
604 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
605 | if (!newsighand) | |
606 | return -ENOMEM; | |
607 | ||
608 | if (thread_group_empty(current)) | |
609 | goto no_thread_group; | |
610 | ||
611 | /* | |
612 | * Kill all other threads in the thread group. | |
613 | * We must hold tasklist_lock to call zap_other_threads. | |
614 | */ | |
615 | read_lock(&tasklist_lock); | |
616 | spin_lock_irq(lock); | |
617 | if (sig->flags & SIGNAL_GROUP_EXIT) { | |
618 | /* | |
619 | * Another group action in progress, just | |
620 | * return so that the signal is processed. | |
621 | */ | |
622 | spin_unlock_irq(lock); | |
623 | read_unlock(&tasklist_lock); | |
624 | kmem_cache_free(sighand_cachep, newsighand); | |
625 | return -EAGAIN; | |
626 | } | |
627 | zap_other_threads(current); | |
628 | read_unlock(&tasklist_lock); | |
629 | ||
630 | /* | |
631 | * Account for the thread group leader hanging around: | |
632 | */ | |
9e4e23bc ON |
633 | count = 1; |
634 | if (!thread_group_leader(current)) { | |
635 | count = 2; | |
53231250 RM |
636 | /* |
637 | * The SIGALRM timer survives the exec, but needs to point | |
638 | * at us as the new group leader now. We have a race with | |
639 | * a timer firing now getting the old leader, so we need to | |
640 | * synchronize with any firing (by calling del_timer_sync) | |
641 | * before we can safely let the old group leader die. | |
642 | */ | |
643 | sig->real_timer.data = (unsigned long)current; | |
932aeafb | 644 | spin_unlock_irq(lock); |
53231250 RM |
645 | if (del_timer_sync(&sig->real_timer)) |
646 | add_timer(&sig->real_timer); | |
932aeafb | 647 | spin_lock_irq(lock); |
53231250 | 648 | } |
1da177e4 LT |
649 | while (atomic_read(&sig->count) > count) { |
650 | sig->group_exit_task = current; | |
651 | sig->notify_count = count; | |
652 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
653 | spin_unlock_irq(lock); | |
654 | schedule(); | |
655 | spin_lock_irq(lock); | |
656 | } | |
657 | sig->group_exit_task = NULL; | |
658 | sig->notify_count = 0; | |
659 | spin_unlock_irq(lock); | |
660 | ||
661 | /* | |
662 | * At this point all other threads have exited, all we have to | |
663 | * do is to wait for the thread group leader to become inactive, | |
664 | * and to assume its PID: | |
665 | */ | |
666 | if (!thread_group_leader(current)) { | |
667 | struct task_struct *leader = current->group_leader, *parent; | |
668 | struct dentry *proc_dentry1, *proc_dentry2; | |
669 | unsigned long exit_state, ptrace; | |
670 | ||
671 | /* | |
672 | * Wait for the thread group leader to be a zombie. | |
673 | * It should already be zombie at this point, most | |
674 | * of the time. | |
675 | */ | |
676 | while (leader->exit_state != EXIT_ZOMBIE) | |
677 | yield(); | |
678 | ||
679 | spin_lock(&leader->proc_lock); | |
680 | spin_lock(¤t->proc_lock); | |
681 | proc_dentry1 = proc_pid_unhash(current); | |
682 | proc_dentry2 = proc_pid_unhash(leader); | |
683 | write_lock_irq(&tasklist_lock); | |
684 | ||
c2a0f594 LT |
685 | BUG_ON(leader->tgid != current->tgid); |
686 | BUG_ON(current->pid == current->tgid); | |
1da177e4 LT |
687 | /* |
688 | * An exec() starts a new thread group with the | |
689 | * TGID of the previous thread group. Rehash the | |
690 | * two threads with a switched PID, and release | |
691 | * the former thread group leader: | |
692 | */ | |
693 | ptrace = leader->ptrace; | |
694 | parent = leader->parent; | |
695 | if (unlikely(ptrace) && unlikely(parent == current)) { | |
696 | /* | |
697 | * Joker was ptracing his own group leader, | |
698 | * and now he wants to be his own parent! | |
699 | * We can't have that. | |
700 | */ | |
701 | ptrace = 0; | |
702 | } | |
703 | ||
704 | ptrace_unlink(current); | |
705 | ptrace_unlink(leader); | |
706 | remove_parent(current); | |
707 | remove_parent(leader); | |
708 | ||
709 | switch_exec_pids(leader, current); | |
710 | ||
711 | current->parent = current->real_parent = leader->real_parent; | |
712 | leader->parent = leader->real_parent = child_reaper; | |
713 | current->group_leader = current; | |
714 | leader->group_leader = leader; | |
715 | ||
716 | add_parent(current, current->parent); | |
717 | add_parent(leader, leader->parent); | |
718 | if (ptrace) { | |
719 | current->ptrace = ptrace; | |
720 | __ptrace_link(current, parent); | |
721 | } | |
722 | ||
723 | list_del(¤t->tasks); | |
724 | list_add_tail(¤t->tasks, &init_task.tasks); | |
725 | current->exit_signal = SIGCHLD; | |
726 | exit_state = leader->exit_state; | |
727 | ||
728 | write_unlock_irq(&tasklist_lock); | |
729 | spin_unlock(&leader->proc_lock); | |
730 | spin_unlock(¤t->proc_lock); | |
731 | proc_pid_flush(proc_dentry1); | |
732 | proc_pid_flush(proc_dentry2); | |
733 | ||
c2a0f594 | 734 | BUG_ON(exit_state != EXIT_ZOMBIE); |
1da177e4 LT |
735 | release_task(leader); |
736 | } | |
737 | ||
738 | /* | |
fb085cf1 AN |
739 | * There may be one thread left which is just exiting, |
740 | * but it's safe to stop telling the group to kill themselves. | |
1da177e4 LT |
741 | */ |
742 | sig->flags = 0; | |
743 | ||
744 | no_thread_group: | |
745 | BUG_ON(atomic_read(&sig->count) != 1); | |
746 | exit_itimers(sig); | |
747 | ||
748 | if (atomic_read(&oldsighand->count) == 1) { | |
749 | /* | |
750 | * Now that we nuked the rest of the thread group, | |
751 | * it turns out we are not sharing sighand any more either. | |
752 | * So we can just keep it. | |
753 | */ | |
754 | kmem_cache_free(sighand_cachep, newsighand); | |
755 | } else { | |
756 | /* | |
757 | * Move our state over to newsighand and switch it in. | |
758 | */ | |
759 | spin_lock_init(&newsighand->siglock); | |
760 | atomic_set(&newsighand->count, 1); | |
761 | memcpy(newsighand->action, oldsighand->action, | |
762 | sizeof(newsighand->action)); | |
763 | ||
764 | write_lock_irq(&tasklist_lock); | |
765 | spin_lock(&oldsighand->siglock); | |
766 | spin_lock(&newsighand->siglock); | |
767 | ||
768 | current->sighand = newsighand; | |
769 | recalc_sigpending(); | |
770 | ||
771 | spin_unlock(&newsighand->siglock); | |
772 | spin_unlock(&oldsighand->siglock); | |
773 | write_unlock_irq(&tasklist_lock); | |
774 | ||
775 | if (atomic_dec_and_test(&oldsighand->count)) | |
776 | kmem_cache_free(sighand_cachep, oldsighand); | |
777 | } | |
778 | ||
c2a0f594 | 779 | BUG_ON(!thread_group_leader(current)); |
1da177e4 LT |
780 | return 0; |
781 | } | |
782 | ||
783 | /* | |
784 | * These functions flushes out all traces of the currently running executable | |
785 | * so that a new one can be started | |
786 | */ | |
787 | ||
788 | static inline void flush_old_files(struct files_struct * files) | |
789 | { | |
790 | long j = -1; | |
badf1662 | 791 | struct fdtable *fdt; |
1da177e4 LT |
792 | |
793 | spin_lock(&files->file_lock); | |
794 | for (;;) { | |
795 | unsigned long set, i; | |
796 | ||
797 | j++; | |
798 | i = j * __NFDBITS; | |
badf1662 DS |
799 | fdt = files_fdtable(files); |
800 | if (i >= fdt->max_fds || i >= fdt->max_fdset) | |
1da177e4 | 801 | break; |
badf1662 | 802 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
803 | if (!set) |
804 | continue; | |
badf1662 | 805 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
806 | spin_unlock(&files->file_lock); |
807 | for ( ; set ; i++,set >>= 1) { | |
808 | if (set & 1) { | |
809 | sys_close(i); | |
810 | } | |
811 | } | |
812 | spin_lock(&files->file_lock); | |
813 | ||
814 | } | |
815 | spin_unlock(&files->file_lock); | |
816 | } | |
817 | ||
818 | void get_task_comm(char *buf, struct task_struct *tsk) | |
819 | { | |
820 | /* buf must be at least sizeof(tsk->comm) in size */ | |
821 | task_lock(tsk); | |
822 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
823 | task_unlock(tsk); | |
824 | } | |
825 | ||
826 | void set_task_comm(struct task_struct *tsk, char *buf) | |
827 | { | |
828 | task_lock(tsk); | |
829 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
830 | task_unlock(tsk); | |
831 | } | |
832 | ||
833 | int flush_old_exec(struct linux_binprm * bprm) | |
834 | { | |
835 | char * name; | |
836 | int i, ch, retval; | |
837 | struct files_struct *files; | |
838 | char tcomm[sizeof(current->comm)]; | |
839 | ||
840 | /* | |
841 | * Make sure we have a private signal table and that | |
842 | * we are unassociated from the previous thread group. | |
843 | */ | |
844 | retval = de_thread(current); | |
845 | if (retval) | |
846 | goto out; | |
847 | ||
848 | /* | |
849 | * Make sure we have private file handles. Ask the | |
850 | * fork helper to do the work for us and the exit | |
851 | * helper to do the cleanup of the old one. | |
852 | */ | |
853 | files = current->files; /* refcounted so safe to hold */ | |
854 | retval = unshare_files(); | |
855 | if (retval) | |
856 | goto out; | |
857 | /* | |
858 | * Release all of the old mmap stuff | |
859 | */ | |
860 | retval = exec_mmap(bprm->mm); | |
861 | if (retval) | |
862 | goto mmap_failed; | |
863 | ||
864 | bprm->mm = NULL; /* We're using it now */ | |
865 | ||
866 | /* This is the point of no return */ | |
867 | steal_locks(files); | |
868 | put_files_struct(files); | |
869 | ||
870 | current->sas_ss_sp = current->sas_ss_size = 0; | |
871 | ||
872 | if (current->euid == current->uid && current->egid == current->gid) | |
873 | current->mm->dumpable = 1; | |
d6e71144 AC |
874 | else |
875 | current->mm->dumpable = suid_dumpable; | |
876 | ||
1da177e4 | 877 | name = bprm->filename; |
36772092 PBG |
878 | |
879 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
880 | for (i=0; (ch = *(name++)) != '\0';) { |
881 | if (ch == '/') | |
36772092 | 882 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
883 | else |
884 | if (i < (sizeof(tcomm) - 1)) | |
885 | tcomm[i++] = ch; | |
886 | } | |
887 | tcomm[i] = '\0'; | |
888 | set_task_comm(current, tcomm); | |
889 | ||
890 | current->flags &= ~PF_RANDOMIZE; | |
891 | flush_thread(); | |
892 | ||
893 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || | |
894 | permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) || | |
895 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { | |
896 | suid_keys(current); | |
d6e71144 | 897 | current->mm->dumpable = suid_dumpable; |
1da177e4 LT |
898 | } |
899 | ||
900 | /* An exec changes our domain. We are no longer part of the thread | |
901 | group */ | |
902 | ||
903 | current->self_exec_id++; | |
904 | ||
905 | flush_signal_handlers(current, 0); | |
906 | flush_old_files(current->files); | |
907 | ||
908 | return 0; | |
909 | ||
910 | mmap_failed: | |
911 | put_files_struct(current->files); | |
912 | current->files = files; | |
913 | out: | |
914 | return retval; | |
915 | } | |
916 | ||
917 | EXPORT_SYMBOL(flush_old_exec); | |
918 | ||
919 | /* | |
920 | * Fill the binprm structure from the inode. | |
921 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
922 | */ | |
923 | int prepare_binprm(struct linux_binprm *bprm) | |
924 | { | |
925 | int mode; | |
926 | struct inode * inode = bprm->file->f_dentry->d_inode; | |
927 | int retval; | |
928 | ||
929 | mode = inode->i_mode; | |
930 | /* | |
931 | * Check execute perms again - if the caller has CAP_DAC_OVERRIDE, | |
932 | * generic_permission lets a non-executable through | |
933 | */ | |
934 | if (!(mode & 0111)) /* with at least _one_ execute bit set */ | |
935 | return -EACCES; | |
936 | if (bprm->file->f_op == NULL) | |
937 | return -EACCES; | |
938 | ||
939 | bprm->e_uid = current->euid; | |
940 | bprm->e_gid = current->egid; | |
941 | ||
942 | if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) { | |
943 | /* Set-uid? */ | |
944 | if (mode & S_ISUID) { | |
945 | current->personality &= ~PER_CLEAR_ON_SETID; | |
946 | bprm->e_uid = inode->i_uid; | |
947 | } | |
948 | ||
949 | /* Set-gid? */ | |
950 | /* | |
951 | * If setgid is set but no group execute bit then this | |
952 | * is a candidate for mandatory locking, not a setgid | |
953 | * executable. | |
954 | */ | |
955 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
956 | current->personality &= ~PER_CLEAR_ON_SETID; | |
957 | bprm->e_gid = inode->i_gid; | |
958 | } | |
959 | } | |
960 | ||
961 | /* fill in binprm security blob */ | |
962 | retval = security_bprm_set(bprm); | |
963 | if (retval) | |
964 | return retval; | |
965 | ||
966 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
967 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
968 | } | |
969 | ||
970 | EXPORT_SYMBOL(prepare_binprm); | |
971 | ||
972 | static inline int unsafe_exec(struct task_struct *p) | |
973 | { | |
974 | int unsafe = 0; | |
975 | if (p->ptrace & PT_PTRACED) { | |
976 | if (p->ptrace & PT_PTRACE_CAP) | |
977 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
978 | else | |
979 | unsafe |= LSM_UNSAFE_PTRACE; | |
980 | } | |
981 | if (atomic_read(&p->fs->count) > 1 || | |
982 | atomic_read(&p->files->count) > 1 || | |
983 | atomic_read(&p->sighand->count) > 1) | |
984 | unsafe |= LSM_UNSAFE_SHARE; | |
985 | ||
986 | return unsafe; | |
987 | } | |
988 | ||
989 | void compute_creds(struct linux_binprm *bprm) | |
990 | { | |
991 | int unsafe; | |
992 | ||
993 | if (bprm->e_uid != current->uid) | |
994 | suid_keys(current); | |
995 | exec_keys(current); | |
996 | ||
997 | task_lock(current); | |
998 | unsafe = unsafe_exec(current); | |
999 | security_bprm_apply_creds(bprm, unsafe); | |
1000 | task_unlock(current); | |
1001 | security_bprm_post_apply_creds(bprm); | |
1002 | } | |
1003 | ||
1004 | EXPORT_SYMBOL(compute_creds); | |
1005 | ||
1006 | void remove_arg_zero(struct linux_binprm *bprm) | |
1007 | { | |
1008 | if (bprm->argc) { | |
1009 | unsigned long offset; | |
1010 | char * kaddr; | |
1011 | struct page *page; | |
1012 | ||
1013 | offset = bprm->p % PAGE_SIZE; | |
1014 | goto inside; | |
1015 | ||
1016 | while (bprm->p++, *(kaddr+offset++)) { | |
1017 | if (offset != PAGE_SIZE) | |
1018 | continue; | |
1019 | offset = 0; | |
1020 | kunmap_atomic(kaddr, KM_USER0); | |
1021 | inside: | |
1022 | page = bprm->page[bprm->p/PAGE_SIZE]; | |
1023 | kaddr = kmap_atomic(page, KM_USER0); | |
1024 | } | |
1025 | kunmap_atomic(kaddr, KM_USER0); | |
1026 | bprm->argc--; | |
1027 | } | |
1028 | } | |
1029 | ||
1030 | EXPORT_SYMBOL(remove_arg_zero); | |
1031 | ||
1032 | /* | |
1033 | * cycle the list of binary formats handler, until one recognizes the image | |
1034 | */ | |
1035 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1036 | { | |
1037 | int try,retval; | |
1038 | struct linux_binfmt *fmt; | |
1039 | #ifdef __alpha__ | |
1040 | /* handle /sbin/loader.. */ | |
1041 | { | |
1042 | struct exec * eh = (struct exec *) bprm->buf; | |
1043 | ||
1044 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1045 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1046 | { | |
1047 | struct file * file; | |
1048 | unsigned long loader; | |
1049 | ||
1050 | allow_write_access(bprm->file); | |
1051 | fput(bprm->file); | |
1052 | bprm->file = NULL; | |
1053 | ||
1054 | loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); | |
1055 | ||
1056 | file = open_exec("/sbin/loader"); | |
1057 | retval = PTR_ERR(file); | |
1058 | if (IS_ERR(file)) | |
1059 | return retval; | |
1060 | ||
1061 | /* Remember if the application is TASO. */ | |
1062 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1063 | ||
1064 | bprm->file = file; | |
1065 | bprm->loader = loader; | |
1066 | retval = prepare_binprm(bprm); | |
1067 | if (retval<0) | |
1068 | return retval; | |
1069 | /* should call search_binary_handler recursively here, | |
1070 | but it does not matter */ | |
1071 | } | |
1072 | } | |
1073 | #endif | |
1074 | retval = security_bprm_check(bprm); | |
1075 | if (retval) | |
1076 | return retval; | |
1077 | ||
1078 | /* kernel module loader fixup */ | |
1079 | /* so we don't try to load run modprobe in kernel space. */ | |
1080 | set_fs(USER_DS); | |
1081 | retval = -ENOENT; | |
1082 | for (try=0; try<2; try++) { | |
1083 | read_lock(&binfmt_lock); | |
1084 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
1085 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; | |
1086 | if (!fn) | |
1087 | continue; | |
1088 | if (!try_module_get(fmt->module)) | |
1089 | continue; | |
1090 | read_unlock(&binfmt_lock); | |
1091 | retval = fn(bprm, regs); | |
1092 | if (retval >= 0) { | |
1093 | put_binfmt(fmt); | |
1094 | allow_write_access(bprm->file); | |
1095 | if (bprm->file) | |
1096 | fput(bprm->file); | |
1097 | bprm->file = NULL; | |
1098 | current->did_exec = 1; | |
1099 | return retval; | |
1100 | } | |
1101 | read_lock(&binfmt_lock); | |
1102 | put_binfmt(fmt); | |
1103 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1104 | break; | |
1105 | if (!bprm->file) { | |
1106 | read_unlock(&binfmt_lock); | |
1107 | return retval; | |
1108 | } | |
1109 | } | |
1110 | read_unlock(&binfmt_lock); | |
1111 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1112 | break; | |
1113 | #ifdef CONFIG_KMOD | |
1114 | }else{ | |
1115 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1116 | if (printable(bprm->buf[0]) && | |
1117 | printable(bprm->buf[1]) && | |
1118 | printable(bprm->buf[2]) && | |
1119 | printable(bprm->buf[3])) | |
1120 | break; /* -ENOEXEC */ | |
1121 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1122 | #endif | |
1123 | } | |
1124 | } | |
1125 | return retval; | |
1126 | } | |
1127 | ||
1128 | EXPORT_SYMBOL(search_binary_handler); | |
1129 | ||
1130 | /* | |
1131 | * sys_execve() executes a new program. | |
1132 | */ | |
1133 | int do_execve(char * filename, | |
1134 | char __user *__user *argv, | |
1135 | char __user *__user *envp, | |
1136 | struct pt_regs * regs) | |
1137 | { | |
1138 | struct linux_binprm *bprm; | |
1139 | struct file *file; | |
1140 | int retval; | |
1141 | int i; | |
1142 | ||
1143 | retval = -ENOMEM; | |
1144 | bprm = kmalloc(sizeof(*bprm), GFP_KERNEL); | |
1145 | if (!bprm) | |
1146 | goto out_ret; | |
1147 | memset(bprm, 0, sizeof(*bprm)); | |
1148 | ||
1149 | file = open_exec(filename); | |
1150 | retval = PTR_ERR(file); | |
1151 | if (IS_ERR(file)) | |
1152 | goto out_kfree; | |
1153 | ||
1154 | sched_exec(); | |
1155 | ||
1156 | bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); | |
1157 | ||
1158 | bprm->file = file; | |
1159 | bprm->filename = filename; | |
1160 | bprm->interp = filename; | |
1161 | bprm->mm = mm_alloc(); | |
1162 | retval = -ENOMEM; | |
1163 | if (!bprm->mm) | |
1164 | goto out_file; | |
1165 | ||
1166 | retval = init_new_context(current, bprm->mm); | |
1167 | if (retval < 0) | |
1168 | goto out_mm; | |
1169 | ||
1170 | bprm->argc = count(argv, bprm->p / sizeof(void *)); | |
1171 | if ((retval = bprm->argc) < 0) | |
1172 | goto out_mm; | |
1173 | ||
1174 | bprm->envc = count(envp, bprm->p / sizeof(void *)); | |
1175 | if ((retval = bprm->envc) < 0) | |
1176 | goto out_mm; | |
1177 | ||
1178 | retval = security_bprm_alloc(bprm); | |
1179 | if (retval) | |
1180 | goto out; | |
1181 | ||
1182 | retval = prepare_binprm(bprm); | |
1183 | if (retval < 0) | |
1184 | goto out; | |
1185 | ||
1186 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1187 | if (retval < 0) | |
1188 | goto out; | |
1189 | ||
1190 | bprm->exec = bprm->p; | |
1191 | retval = copy_strings(bprm->envc, envp, bprm); | |
1192 | if (retval < 0) | |
1193 | goto out; | |
1194 | ||
1195 | retval = copy_strings(bprm->argc, argv, bprm); | |
1196 | if (retval < 0) | |
1197 | goto out; | |
1198 | ||
1199 | retval = search_binary_handler(bprm,regs); | |
1200 | if (retval >= 0) { | |
1201 | free_arg_pages(bprm); | |
1202 | ||
1203 | /* execve success */ | |
1204 | security_bprm_free(bprm); | |
1205 | acct_update_integrals(current); | |
1da177e4 LT |
1206 | kfree(bprm); |
1207 | return retval; | |
1208 | } | |
1209 | ||
1210 | out: | |
1211 | /* Something went wrong, return the inode and free the argument pages*/ | |
1212 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) { | |
1213 | struct page * page = bprm->page[i]; | |
1214 | if (page) | |
1215 | __free_page(page); | |
1216 | } | |
1217 | ||
1218 | if (bprm->security) | |
1219 | security_bprm_free(bprm); | |
1220 | ||
1221 | out_mm: | |
1222 | if (bprm->mm) | |
1223 | mmdrop(bprm->mm); | |
1224 | ||
1225 | out_file: | |
1226 | if (bprm->file) { | |
1227 | allow_write_access(bprm->file); | |
1228 | fput(bprm->file); | |
1229 | } | |
1230 | ||
1231 | out_kfree: | |
1232 | kfree(bprm); | |
1233 | ||
1234 | out_ret: | |
1235 | return retval; | |
1236 | } | |
1237 | ||
1238 | int set_binfmt(struct linux_binfmt *new) | |
1239 | { | |
1240 | struct linux_binfmt *old = current->binfmt; | |
1241 | ||
1242 | if (new) { | |
1243 | if (!try_module_get(new->module)) | |
1244 | return -1; | |
1245 | } | |
1246 | current->binfmt = new; | |
1247 | if (old) | |
1248 | module_put(old->module); | |
1249 | return 0; | |
1250 | } | |
1251 | ||
1252 | EXPORT_SYMBOL(set_binfmt); | |
1253 | ||
1254 | #define CORENAME_MAX_SIZE 64 | |
1255 | ||
1256 | /* format_corename will inspect the pattern parameter, and output a | |
1257 | * name into corename, which must have space for at least | |
1258 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1259 | */ | |
1260 | static void format_corename(char *corename, const char *pattern, long signr) | |
1261 | { | |
1262 | const char *pat_ptr = pattern; | |
1263 | char *out_ptr = corename; | |
1264 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1265 | int rc; | |
1266 | int pid_in_pattern = 0; | |
1267 | ||
1268 | /* Repeat as long as we have more pattern to process and more output | |
1269 | space */ | |
1270 | while (*pat_ptr) { | |
1271 | if (*pat_ptr != '%') { | |
1272 | if (out_ptr == out_end) | |
1273 | goto out; | |
1274 | *out_ptr++ = *pat_ptr++; | |
1275 | } else { | |
1276 | switch (*++pat_ptr) { | |
1277 | case 0: | |
1278 | goto out; | |
1279 | /* Double percent, output one percent */ | |
1280 | case '%': | |
1281 | if (out_ptr == out_end) | |
1282 | goto out; | |
1283 | *out_ptr++ = '%'; | |
1284 | break; | |
1285 | /* pid */ | |
1286 | case 'p': | |
1287 | pid_in_pattern = 1; | |
1288 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1289 | "%d", current->tgid); | |
1290 | if (rc > out_end - out_ptr) | |
1291 | goto out; | |
1292 | out_ptr += rc; | |
1293 | break; | |
1294 | /* uid */ | |
1295 | case 'u': | |
1296 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1297 | "%d", current->uid); | |
1298 | if (rc > out_end - out_ptr) | |
1299 | goto out; | |
1300 | out_ptr += rc; | |
1301 | break; | |
1302 | /* gid */ | |
1303 | case 'g': | |
1304 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1305 | "%d", current->gid); | |
1306 | if (rc > out_end - out_ptr) | |
1307 | goto out; | |
1308 | out_ptr += rc; | |
1309 | break; | |
1310 | /* signal that caused the coredump */ | |
1311 | case 's': | |
1312 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1313 | "%ld", signr); | |
1314 | if (rc > out_end - out_ptr) | |
1315 | goto out; | |
1316 | out_ptr += rc; | |
1317 | break; | |
1318 | /* UNIX time of coredump */ | |
1319 | case 't': { | |
1320 | struct timeval tv; | |
1321 | do_gettimeofday(&tv); | |
1322 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1323 | "%lu", tv.tv_sec); | |
1324 | if (rc > out_end - out_ptr) | |
1325 | goto out; | |
1326 | out_ptr += rc; | |
1327 | break; | |
1328 | } | |
1329 | /* hostname */ | |
1330 | case 'h': | |
1331 | down_read(&uts_sem); | |
1332 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1333 | "%s", system_utsname.nodename); | |
1334 | up_read(&uts_sem); | |
1335 | if (rc > out_end - out_ptr) | |
1336 | goto out; | |
1337 | out_ptr += rc; | |
1338 | break; | |
1339 | /* executable */ | |
1340 | case 'e': | |
1341 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1342 | "%s", current->comm); | |
1343 | if (rc > out_end - out_ptr) | |
1344 | goto out; | |
1345 | out_ptr += rc; | |
1346 | break; | |
1347 | default: | |
1348 | break; | |
1349 | } | |
1350 | ++pat_ptr; | |
1351 | } | |
1352 | } | |
1353 | /* Backward compatibility with core_uses_pid: | |
1354 | * | |
1355 | * If core_pattern does not include a %p (as is the default) | |
1356 | * and core_uses_pid is set, then .%pid will be appended to | |
1357 | * the filename */ | |
1358 | if (!pid_in_pattern | |
1359 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { | |
1360 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1361 | ".%d", current->tgid); | |
1362 | if (rc > out_end - out_ptr) | |
1363 | goto out; | |
1364 | out_ptr += rc; | |
1365 | } | |
1366 | out: | |
1367 | *out_ptr = 0; | |
1368 | } | |
1369 | ||
1370 | static void zap_threads (struct mm_struct *mm) | |
1371 | { | |
1372 | struct task_struct *g, *p; | |
1373 | struct task_struct *tsk = current; | |
1374 | struct completion *vfork_done = tsk->vfork_done; | |
1375 | int traced = 0; | |
1376 | ||
1377 | /* | |
1378 | * Make sure nobody is waiting for us to release the VM, | |
1379 | * otherwise we can deadlock when we wait on each other | |
1380 | */ | |
1381 | if (vfork_done) { | |
1382 | tsk->vfork_done = NULL; | |
1383 | complete(vfork_done); | |
1384 | } | |
1385 | ||
1386 | read_lock(&tasklist_lock); | |
1387 | do_each_thread(g,p) | |
1388 | if (mm == p->mm && p != tsk) { | |
1389 | force_sig_specific(SIGKILL, p); | |
1390 | mm->core_waiters++; | |
1391 | if (unlikely(p->ptrace) && | |
1392 | unlikely(p->parent->mm == mm)) | |
1393 | traced = 1; | |
1394 | } | |
1395 | while_each_thread(g,p); | |
1396 | ||
1397 | read_unlock(&tasklist_lock); | |
1398 | ||
1399 | if (unlikely(traced)) { | |
1400 | /* | |
1401 | * We are zapping a thread and the thread it ptraces. | |
1402 | * If the tracee went into a ptrace stop for exit tracing, | |
1403 | * we could deadlock since the tracer is waiting for this | |
1404 | * coredump to finish. Detach them so they can both die. | |
1405 | */ | |
1406 | write_lock_irq(&tasklist_lock); | |
1407 | do_each_thread(g,p) { | |
1408 | if (mm == p->mm && p != tsk && | |
1409 | p->ptrace && p->parent->mm == mm) { | |
1410 | __ptrace_unlink(p); | |
1411 | } | |
1412 | } while_each_thread(g,p); | |
1413 | write_unlock_irq(&tasklist_lock); | |
1414 | } | |
1415 | } | |
1416 | ||
1417 | static void coredump_wait(struct mm_struct *mm) | |
1418 | { | |
1419 | DECLARE_COMPLETION(startup_done); | |
2384f55f | 1420 | int core_waiters; |
1da177e4 | 1421 | |
1da177e4 LT |
1422 | mm->core_startup_done = &startup_done; |
1423 | ||
1da177e4 | 1424 | zap_threads(mm); |
2384f55f ON |
1425 | core_waiters = mm->core_waiters; |
1426 | up_write(&mm->mmap_sem); | |
1427 | ||
1428 | if (core_waiters) | |
1da177e4 | 1429 | wait_for_completion(&startup_done); |
1da177e4 LT |
1430 | BUG_ON(mm->core_waiters); |
1431 | } | |
1432 | ||
1433 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) | |
1434 | { | |
1435 | char corename[CORENAME_MAX_SIZE + 1]; | |
1436 | struct mm_struct *mm = current->mm; | |
1437 | struct linux_binfmt * binfmt; | |
1438 | struct inode * inode; | |
1439 | struct file * file; | |
1440 | int retval = 0; | |
d6e71144 AC |
1441 | int fsuid = current->fsuid; |
1442 | int flag = 0; | |
1da177e4 LT |
1443 | |
1444 | binfmt = current->binfmt; | |
1445 | if (!binfmt || !binfmt->core_dump) | |
1446 | goto fail; | |
1447 | down_write(&mm->mmap_sem); | |
1448 | if (!mm->dumpable) { | |
1449 | up_write(&mm->mmap_sem); | |
1450 | goto fail; | |
1451 | } | |
d6e71144 AC |
1452 | |
1453 | /* | |
1454 | * We cannot trust fsuid as being the "true" uid of the | |
1455 | * process nor do we know its entire history. We only know it | |
1456 | * was tainted so we dump it as root in mode 2. | |
1457 | */ | |
1458 | if (mm->dumpable == 2) { /* Setuid core dump mode */ | |
1459 | flag = O_EXCL; /* Stop rewrite attacks */ | |
1460 | current->fsuid = 0; /* Dump root private */ | |
1461 | } | |
1da177e4 LT |
1462 | mm->dumpable = 0; |
1463 | init_completion(&mm->core_done); | |
1464 | spin_lock_irq(¤t->sighand->siglock); | |
1465 | current->signal->flags = SIGNAL_GROUP_EXIT; | |
1466 | current->signal->group_exit_code = exit_code; | |
1467 | spin_unlock_irq(¤t->sighand->siglock); | |
1468 | coredump_wait(mm); | |
1469 | ||
1470 | /* | |
1471 | * Clear any false indication of pending signals that might | |
1472 | * be seen by the filesystem code called to write the core file. | |
1473 | */ | |
1474 | current->signal->group_stop_count = 0; | |
1475 | clear_thread_flag(TIF_SIGPENDING); | |
1476 | ||
1477 | if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) | |
1478 | goto fail_unlock; | |
1479 | ||
1480 | /* | |
1481 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1482 | * uses lock_kernel() | |
1483 | */ | |
1484 | lock_kernel(); | |
1485 | format_corename(corename, core_pattern, signr); | |
1486 | unlock_kernel(); | |
d6e71144 | 1487 | file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600); |
1da177e4 LT |
1488 | if (IS_ERR(file)) |
1489 | goto fail_unlock; | |
1490 | inode = file->f_dentry->d_inode; | |
1491 | if (inode->i_nlink > 1) | |
1492 | goto close_fail; /* multiple links - don't dump */ | |
1493 | if (d_unhashed(file->f_dentry)) | |
1494 | goto close_fail; | |
1495 | ||
1496 | if (!S_ISREG(inode->i_mode)) | |
1497 | goto close_fail; | |
1498 | if (!file->f_op) | |
1499 | goto close_fail; | |
1500 | if (!file->f_op->write) | |
1501 | goto close_fail; | |
1502 | if (do_truncate(file->f_dentry, 0) != 0) | |
1503 | goto close_fail; | |
1504 | ||
1505 | retval = binfmt->core_dump(signr, regs, file); | |
1506 | ||
1507 | if (retval) | |
1508 | current->signal->group_exit_code |= 0x80; | |
1509 | close_fail: | |
1510 | filp_close(file, NULL); | |
1511 | fail_unlock: | |
d6e71144 | 1512 | current->fsuid = fsuid; |
1da177e4 LT |
1513 | complete_all(&mm->core_done); |
1514 | fail: | |
1515 | return retval; | |
1516 | } |