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> | |
9f46080c | 51 | #include <linux/cn_proc.h> |
473ae30b | 52 | #include <linux/audit.h> |
1da177e4 LT |
53 | |
54 | #include <asm/uaccess.h> | |
55 | #include <asm/mmu_context.h> | |
56 | ||
57 | #ifdef CONFIG_KMOD | |
58 | #include <linux/kmod.h> | |
59 | #endif | |
60 | ||
61 | int core_uses_pid; | |
62 | char core_pattern[65] = "core"; | |
d6e71144 AC |
63 | int suid_dumpable = 0; |
64 | ||
65 | EXPORT_SYMBOL(suid_dumpable); | |
1da177e4 LT |
66 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
67 | ||
68 | static struct linux_binfmt *formats; | |
69 | static DEFINE_RWLOCK(binfmt_lock); | |
70 | ||
71 | int register_binfmt(struct linux_binfmt * fmt) | |
72 | { | |
73 | struct linux_binfmt ** tmp = &formats; | |
74 | ||
75 | if (!fmt) | |
76 | return -EINVAL; | |
77 | if (fmt->next) | |
78 | return -EBUSY; | |
79 | write_lock(&binfmt_lock); | |
80 | while (*tmp) { | |
81 | if (fmt == *tmp) { | |
82 | write_unlock(&binfmt_lock); | |
83 | return -EBUSY; | |
84 | } | |
85 | tmp = &(*tmp)->next; | |
86 | } | |
87 | fmt->next = formats; | |
88 | formats = fmt; | |
89 | write_unlock(&binfmt_lock); | |
90 | return 0; | |
91 | } | |
92 | ||
93 | EXPORT_SYMBOL(register_binfmt); | |
94 | ||
95 | int unregister_binfmt(struct linux_binfmt * fmt) | |
96 | { | |
97 | struct linux_binfmt ** tmp = &formats; | |
98 | ||
99 | write_lock(&binfmt_lock); | |
100 | while (*tmp) { | |
101 | if (fmt == *tmp) { | |
102 | *tmp = fmt->next; | |
103 | write_unlock(&binfmt_lock); | |
104 | return 0; | |
105 | } | |
106 | tmp = &(*tmp)->next; | |
107 | } | |
108 | write_unlock(&binfmt_lock); | |
109 | return -EINVAL; | |
110 | } | |
111 | ||
112 | EXPORT_SYMBOL(unregister_binfmt); | |
113 | ||
114 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
115 | { | |
116 | module_put(fmt->module); | |
117 | } | |
118 | ||
119 | /* | |
120 | * Note that a shared library must be both readable and executable due to | |
121 | * security reasons. | |
122 | * | |
123 | * Also note that we take the address to load from from the file itself. | |
124 | */ | |
125 | asmlinkage long sys_uselib(const char __user * library) | |
126 | { | |
127 | struct file * file; | |
128 | struct nameidata nd; | |
129 | int error; | |
130 | ||
b500531e | 131 | error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
132 | if (error) |
133 | goto out; | |
134 | ||
135 | error = -EINVAL; | |
136 | if (!S_ISREG(nd.dentry->d_inode->i_mode)) | |
137 | goto exit; | |
138 | ||
e4543edd | 139 | error = vfs_permission(&nd, MAY_READ | MAY_EXEC); |
1da177e4 LT |
140 | if (error) |
141 | goto exit; | |
142 | ||
834f2a4a | 143 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
144 | error = PTR_ERR(file); |
145 | if (IS_ERR(file)) | |
146 | goto out; | |
147 | ||
148 | error = -ENOEXEC; | |
149 | if(file->f_op) { | |
150 | struct linux_binfmt * fmt; | |
151 | ||
152 | read_lock(&binfmt_lock); | |
153 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
154 | if (!fmt->load_shlib) | |
155 | continue; | |
156 | if (!try_module_get(fmt->module)) | |
157 | continue; | |
158 | read_unlock(&binfmt_lock); | |
159 | error = fmt->load_shlib(file); | |
160 | read_lock(&binfmt_lock); | |
161 | put_binfmt(fmt); | |
162 | if (error != -ENOEXEC) | |
163 | break; | |
164 | } | |
165 | read_unlock(&binfmt_lock); | |
166 | } | |
167 | fput(file); | |
168 | out: | |
169 | return error; | |
170 | exit: | |
834f2a4a | 171 | release_open_intent(&nd); |
1da177e4 LT |
172 | path_release(&nd); |
173 | goto out; | |
174 | } | |
175 | ||
176 | /* | |
177 | * count() counts the number of strings in array ARGV. | |
178 | */ | |
179 | static int count(char __user * __user * argv, int max) | |
180 | { | |
181 | int i = 0; | |
182 | ||
183 | if (argv != NULL) { | |
184 | for (;;) { | |
185 | char __user * p; | |
186 | ||
187 | if (get_user(p, argv)) | |
188 | return -EFAULT; | |
189 | if (!p) | |
190 | break; | |
191 | argv++; | |
192 | if(++i > max) | |
193 | return -E2BIG; | |
194 | cond_resched(); | |
195 | } | |
196 | } | |
197 | return i; | |
198 | } | |
199 | ||
200 | /* | |
201 | * 'copy_strings()' copies argument/environment strings from user | |
202 | * memory to free pages in kernel mem. These are in a format ready | |
203 | * to be put directly into the top of new user memory. | |
204 | */ | |
75c96f85 AB |
205 | static int copy_strings(int argc, char __user * __user * argv, |
206 | struct linux_binprm *bprm) | |
1da177e4 LT |
207 | { |
208 | struct page *kmapped_page = NULL; | |
209 | char *kaddr = NULL; | |
210 | int ret; | |
211 | ||
212 | while (argc-- > 0) { | |
213 | char __user *str; | |
214 | int len; | |
215 | unsigned long pos; | |
216 | ||
217 | if (get_user(str, argv+argc) || | |
218 | !(len = strnlen_user(str, bprm->p))) { | |
219 | ret = -EFAULT; | |
220 | goto out; | |
221 | } | |
222 | ||
223 | if (bprm->p < len) { | |
224 | ret = -E2BIG; | |
225 | goto out; | |
226 | } | |
227 | ||
228 | bprm->p -= len; | |
229 | /* XXX: add architecture specific overflow check here. */ | |
230 | pos = bprm->p; | |
231 | ||
232 | while (len > 0) { | |
233 | int i, new, err; | |
234 | int offset, bytes_to_copy; | |
235 | struct page *page; | |
236 | ||
237 | offset = pos % PAGE_SIZE; | |
238 | i = pos/PAGE_SIZE; | |
239 | page = bprm->page[i]; | |
240 | new = 0; | |
241 | if (!page) { | |
242 | page = alloc_page(GFP_HIGHUSER); | |
243 | bprm->page[i] = page; | |
244 | if (!page) { | |
245 | ret = -ENOMEM; | |
246 | goto out; | |
247 | } | |
248 | new = 1; | |
249 | } | |
250 | ||
251 | if (page != kmapped_page) { | |
252 | if (kmapped_page) | |
253 | kunmap(kmapped_page); | |
254 | kmapped_page = page; | |
255 | kaddr = kmap(kmapped_page); | |
256 | } | |
257 | if (new && offset) | |
258 | memset(kaddr, 0, offset); | |
259 | bytes_to_copy = PAGE_SIZE - offset; | |
260 | if (bytes_to_copy > len) { | |
261 | bytes_to_copy = len; | |
262 | if (new) | |
263 | memset(kaddr+offset+len, 0, | |
264 | PAGE_SIZE-offset-len); | |
265 | } | |
266 | err = copy_from_user(kaddr+offset, str, bytes_to_copy); | |
267 | if (err) { | |
268 | ret = -EFAULT; | |
269 | goto out; | |
270 | } | |
271 | ||
272 | pos += bytes_to_copy; | |
273 | str += bytes_to_copy; | |
274 | len -= bytes_to_copy; | |
275 | } | |
276 | } | |
277 | ret = 0; | |
278 | out: | |
279 | if (kmapped_page) | |
280 | kunmap(kmapped_page); | |
281 | return ret; | |
282 | } | |
283 | ||
284 | /* | |
285 | * Like copy_strings, but get argv and its values from kernel memory. | |
286 | */ | |
287 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) | |
288 | { | |
289 | int r; | |
290 | mm_segment_t oldfs = get_fs(); | |
291 | set_fs(KERNEL_DS); | |
292 | r = copy_strings(argc, (char __user * __user *)argv, bprm); | |
293 | set_fs(oldfs); | |
294 | return r; | |
295 | } | |
296 | ||
297 | EXPORT_SYMBOL(copy_strings_kernel); | |
298 | ||
299 | #ifdef CONFIG_MMU | |
300 | /* | |
301 | * This routine is used to map in a page into an address space: needed by | |
302 | * execve() for the initial stack and environment pages. | |
303 | * | |
304 | * vma->vm_mm->mmap_sem is held for writing. | |
305 | */ | |
306 | void install_arg_page(struct vm_area_struct *vma, | |
307 | struct page *page, unsigned long address) | |
308 | { | |
309 | struct mm_struct *mm = vma->vm_mm; | |
1da177e4 | 310 | pte_t * pte; |
c74df32c | 311 | spinlock_t *ptl; |
1da177e4 LT |
312 | |
313 | if (unlikely(anon_vma_prepare(vma))) | |
c74df32c | 314 | goto out; |
1da177e4 LT |
315 | |
316 | flush_dcache_page(page); | |
c9cfcddf | 317 | pte = get_locked_pte(mm, address, &ptl); |
1da177e4 LT |
318 | if (!pte) |
319 | goto out; | |
320 | if (!pte_none(*pte)) { | |
c74df32c | 321 | pte_unmap_unlock(pte, ptl); |
1da177e4 LT |
322 | goto out; |
323 | } | |
4294621f | 324 | inc_mm_counter(mm, anon_rss); |
1da177e4 LT |
325 | lru_cache_add_active(page); |
326 | set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte( | |
327 | page, vma->vm_page_prot)))); | |
9617d95e | 328 | page_add_new_anon_rmap(page, vma, address); |
c74df32c | 329 | pte_unmap_unlock(pte, ptl); |
1da177e4 LT |
330 | |
331 | /* no need for flush_tlb */ | |
332 | return; | |
333 | out: | |
1da177e4 LT |
334 | __free_page(page); |
335 | force_sig(SIGKILL, current); | |
336 | } | |
337 | ||
338 | #define EXTRA_STACK_VM_PAGES 20 /* random */ | |
339 | ||
340 | int setup_arg_pages(struct linux_binprm *bprm, | |
341 | unsigned long stack_top, | |
342 | int executable_stack) | |
343 | { | |
344 | unsigned long stack_base; | |
345 | struct vm_area_struct *mpnt; | |
346 | struct mm_struct *mm = current->mm; | |
347 | int i, ret; | |
348 | long arg_size; | |
349 | ||
350 | #ifdef CONFIG_STACK_GROWSUP | |
351 | /* Move the argument and environment strings to the bottom of the | |
352 | * stack space. | |
353 | */ | |
354 | int offset, j; | |
355 | char *to, *from; | |
356 | ||
357 | /* Start by shifting all the pages down */ | |
358 | i = 0; | |
359 | for (j = 0; j < MAX_ARG_PAGES; j++) { | |
360 | struct page *page = bprm->page[j]; | |
361 | if (!page) | |
362 | continue; | |
363 | bprm->page[i++] = page; | |
364 | } | |
365 | ||
366 | /* Now move them within their pages */ | |
367 | offset = bprm->p % PAGE_SIZE; | |
368 | to = kmap(bprm->page[0]); | |
369 | for (j = 1; j < i; j++) { | |
370 | memmove(to, to + offset, PAGE_SIZE - offset); | |
371 | from = kmap(bprm->page[j]); | |
372 | memcpy(to + PAGE_SIZE - offset, from, offset); | |
373 | kunmap(bprm->page[j - 1]); | |
374 | to = from; | |
375 | } | |
376 | memmove(to, to + offset, PAGE_SIZE - offset); | |
377 | kunmap(bprm->page[j - 1]); | |
378 | ||
379 | /* Limit stack size to 1GB */ | |
380 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; | |
381 | if (stack_base > (1 << 30)) | |
382 | stack_base = 1 << 30; | |
383 | stack_base = PAGE_ALIGN(stack_top - stack_base); | |
384 | ||
385 | /* Adjust bprm->p to point to the end of the strings. */ | |
386 | bprm->p = stack_base + PAGE_SIZE * i - offset; | |
387 | ||
388 | mm->arg_start = stack_base; | |
389 | arg_size = i << PAGE_SHIFT; | |
390 | ||
391 | /* zero pages that were copied above */ | |
392 | while (i < MAX_ARG_PAGES) | |
393 | bprm->page[i++] = NULL; | |
394 | #else | |
395 | stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE); | |
396 | stack_base = PAGE_ALIGN(stack_base); | |
397 | bprm->p += stack_base; | |
398 | mm->arg_start = bprm->p; | |
399 | arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start); | |
400 | #endif | |
401 | ||
402 | arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE; | |
403 | ||
404 | if (bprm->loader) | |
405 | bprm->loader += stack_base; | |
406 | bprm->exec += stack_base; | |
407 | ||
408 | mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); | |
409 | if (!mpnt) | |
410 | return -ENOMEM; | |
411 | ||
1da177e4 LT |
412 | memset(mpnt, 0, sizeof(*mpnt)); |
413 | ||
414 | down_write(&mm->mmap_sem); | |
415 | { | |
416 | mpnt->vm_mm = mm; | |
417 | #ifdef CONFIG_STACK_GROWSUP | |
418 | mpnt->vm_start = stack_base; | |
419 | mpnt->vm_end = stack_base + arg_size; | |
420 | #else | |
421 | mpnt->vm_end = stack_top; | |
422 | mpnt->vm_start = mpnt->vm_end - arg_size; | |
423 | #endif | |
424 | /* Adjust stack execute permissions; explicitly enable | |
425 | * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X | |
426 | * and leave alone (arch default) otherwise. */ | |
427 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
428 | mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC; | |
429 | else if (executable_stack == EXSTACK_DISABLE_X) | |
430 | mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC; | |
431 | else | |
432 | mpnt->vm_flags = VM_STACK_FLAGS; | |
433 | mpnt->vm_flags |= mm->def_flags; | |
434 | mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7]; | |
435 | if ((ret = insert_vm_struct(mm, mpnt))) { | |
436 | up_write(&mm->mmap_sem); | |
437 | kmem_cache_free(vm_area_cachep, mpnt); | |
438 | return ret; | |
439 | } | |
440 | mm->stack_vm = mm->total_vm = vma_pages(mpnt); | |
441 | } | |
442 | ||
443 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) { | |
444 | struct page *page = bprm->page[i]; | |
445 | if (page) { | |
446 | bprm->page[i] = NULL; | |
447 | install_arg_page(mpnt, page, stack_base); | |
448 | } | |
449 | stack_base += PAGE_SIZE; | |
450 | } | |
451 | up_write(&mm->mmap_sem); | |
452 | ||
453 | return 0; | |
454 | } | |
455 | ||
456 | EXPORT_SYMBOL(setup_arg_pages); | |
457 | ||
458 | #define free_arg_pages(bprm) do { } while (0) | |
459 | ||
460 | #else | |
461 | ||
462 | static inline void free_arg_pages(struct linux_binprm *bprm) | |
463 | { | |
464 | int i; | |
465 | ||
466 | for (i = 0; i < MAX_ARG_PAGES; i++) { | |
467 | if (bprm->page[i]) | |
468 | __free_page(bprm->page[i]); | |
469 | bprm->page[i] = NULL; | |
470 | } | |
471 | } | |
472 | ||
473 | #endif /* CONFIG_MMU */ | |
474 | ||
475 | struct file *open_exec(const char *name) | |
476 | { | |
477 | struct nameidata nd; | |
478 | int err; | |
479 | struct file *file; | |
480 | ||
b500531e | 481 | err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); |
1da177e4 LT |
482 | file = ERR_PTR(err); |
483 | ||
484 | if (!err) { | |
485 | struct inode *inode = nd.dentry->d_inode; | |
486 | file = ERR_PTR(-EACCES); | |
487 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && | |
488 | S_ISREG(inode->i_mode)) { | |
e4543edd | 489 | int err = vfs_permission(&nd, MAY_EXEC); |
1da177e4 LT |
490 | if (!err && !(inode->i_mode & 0111)) |
491 | err = -EACCES; | |
492 | file = ERR_PTR(err); | |
493 | if (!err) { | |
834f2a4a | 494 | file = nameidata_to_filp(&nd, O_RDONLY); |
1da177e4 LT |
495 | if (!IS_ERR(file)) { |
496 | err = deny_write_access(file); | |
497 | if (err) { | |
498 | fput(file); | |
499 | file = ERR_PTR(err); | |
500 | } | |
501 | } | |
502 | out: | |
503 | return file; | |
504 | } | |
505 | } | |
834f2a4a | 506 | release_open_intent(&nd); |
1da177e4 LT |
507 | path_release(&nd); |
508 | } | |
509 | goto out; | |
510 | } | |
511 | ||
512 | EXPORT_SYMBOL(open_exec); | |
513 | ||
514 | int kernel_read(struct file *file, unsigned long offset, | |
515 | char *addr, unsigned long count) | |
516 | { | |
517 | mm_segment_t old_fs; | |
518 | loff_t pos = offset; | |
519 | int result; | |
520 | ||
521 | old_fs = get_fs(); | |
522 | set_fs(get_ds()); | |
523 | /* The cast to a user pointer is valid due to the set_fs() */ | |
524 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
525 | set_fs(old_fs); | |
526 | return result; | |
527 | } | |
528 | ||
529 | EXPORT_SYMBOL(kernel_read); | |
530 | ||
531 | static int exec_mmap(struct mm_struct *mm) | |
532 | { | |
533 | struct task_struct *tsk; | |
534 | struct mm_struct * old_mm, *active_mm; | |
535 | ||
536 | /* Notify parent that we're no longer interested in the old VM */ | |
537 | tsk = current; | |
538 | old_mm = current->mm; | |
539 | mm_release(tsk, old_mm); | |
540 | ||
541 | if (old_mm) { | |
542 | /* | |
543 | * Make sure that if there is a core dump in progress | |
544 | * for the old mm, we get out and die instead of going | |
545 | * through with the exec. We must hold mmap_sem around | |
546 | * checking core_waiters and changing tsk->mm. The | |
547 | * core-inducing thread will increment core_waiters for | |
548 | * each thread whose ->mm == old_mm. | |
549 | */ | |
550 | down_read(&old_mm->mmap_sem); | |
551 | if (unlikely(old_mm->core_waiters)) { | |
552 | up_read(&old_mm->mmap_sem); | |
553 | return -EINTR; | |
554 | } | |
555 | } | |
556 | task_lock(tsk); | |
557 | active_mm = tsk->active_mm; | |
558 | tsk->mm = mm; | |
559 | tsk->active_mm = mm; | |
560 | activate_mm(active_mm, mm); | |
561 | task_unlock(tsk); | |
562 | arch_pick_mmap_layout(mm); | |
563 | if (old_mm) { | |
564 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 565 | BUG_ON(active_mm != old_mm); |
1da177e4 LT |
566 | mmput(old_mm); |
567 | return 0; | |
568 | } | |
569 | mmdrop(active_mm); | |
570 | return 0; | |
571 | } | |
572 | ||
573 | /* | |
574 | * This function makes sure the current process has its own signal table, | |
575 | * so that flush_signal_handlers can later reset the handlers without | |
576 | * disturbing other processes. (Other processes might share the signal | |
577 | * table via the CLONE_SIGHAND option to clone().) | |
578 | */ | |
858119e1 | 579 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
580 | { |
581 | struct signal_struct *sig = tsk->signal; | |
582 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand; | |
583 | spinlock_t *lock = &oldsighand->siglock; | |
329f7dba | 584 | struct task_struct *leader = NULL; |
1da177e4 LT |
585 | int count; |
586 | ||
587 | /* | |
588 | * If we don't share sighandlers, then we aren't sharing anything | |
589 | * and we can just re-use it all. | |
590 | */ | |
591 | if (atomic_read(&oldsighand->count) <= 1) { | |
592 | BUG_ON(atomic_read(&sig->count) != 1); | |
593 | exit_itimers(sig); | |
594 | return 0; | |
595 | } | |
596 | ||
597 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); | |
598 | if (!newsighand) | |
599 | return -ENOMEM; | |
600 | ||
601 | if (thread_group_empty(current)) | |
602 | goto no_thread_group; | |
603 | ||
604 | /* | |
605 | * Kill all other threads in the thread group. | |
606 | * We must hold tasklist_lock to call zap_other_threads. | |
607 | */ | |
608 | read_lock(&tasklist_lock); | |
609 | spin_lock_irq(lock); | |
610 | if (sig->flags & SIGNAL_GROUP_EXIT) { | |
611 | /* | |
612 | * Another group action in progress, just | |
613 | * return so that the signal is processed. | |
614 | */ | |
615 | spin_unlock_irq(lock); | |
616 | read_unlock(&tasklist_lock); | |
617 | kmem_cache_free(sighand_cachep, newsighand); | |
618 | return -EAGAIN; | |
619 | } | |
1434261c ON |
620 | |
621 | /* | |
622 | * child_reaper ignores SIGKILL, change it now. | |
623 | * Reparenting needs write_lock on tasklist_lock, | |
624 | * so it is safe to do it under read_lock. | |
625 | */ | |
626 | if (unlikely(current->group_leader == child_reaper)) | |
627 | child_reaper = current; | |
628 | ||
1da177e4 LT |
629 | zap_other_threads(current); |
630 | read_unlock(&tasklist_lock); | |
631 | ||
632 | /* | |
633 | * Account for the thread group leader hanging around: | |
634 | */ | |
9e4e23bc ON |
635 | count = 1; |
636 | if (!thread_group_leader(current)) { | |
637 | count = 2; | |
53231250 RM |
638 | /* |
639 | * The SIGALRM timer survives the exec, but needs to point | |
640 | * at us as the new group leader now. We have a race with | |
641 | * a timer firing now getting the old leader, so we need to | |
642 | * synchronize with any firing (by calling del_timer_sync) | |
643 | * before we can safely let the old group leader die. | |
644 | */ | |
05cfb614 | 645 | sig->tsk = current; |
932aeafb | 646 | spin_unlock_irq(lock); |
2ff678b8 TG |
647 | if (hrtimer_cancel(&sig->real_timer)) |
648 | hrtimer_restart(&sig->real_timer); | |
932aeafb | 649 | spin_lock_irq(lock); |
53231250 | 650 | } |
1da177e4 LT |
651 | while (atomic_read(&sig->count) > count) { |
652 | sig->group_exit_task = current; | |
653 | sig->notify_count = count; | |
654 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
655 | spin_unlock_irq(lock); | |
656 | schedule(); | |
657 | spin_lock_irq(lock); | |
658 | } | |
659 | sig->group_exit_task = NULL; | |
660 | sig->notify_count = 0; | |
661 | spin_unlock_irq(lock); | |
662 | ||
663 | /* | |
664 | * At this point all other threads have exited, all we have to | |
665 | * do is to wait for the thread group leader to become inactive, | |
666 | * and to assume its PID: | |
667 | */ | |
668 | if (!thread_group_leader(current)) { | |
1da177e4 | 669 | struct dentry *proc_dentry1, *proc_dentry2; |
1da177e4 LT |
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 | */ | |
1434261c | 676 | leader = current->group_leader; |
1da177e4 LT |
677 | while (leader->exit_state != EXIT_ZOMBIE) |
678 | yield(); | |
679 | ||
f5e90281 RM |
680 | /* |
681 | * The only record we have of the real-time age of a | |
682 | * process, regardless of execs it's done, is start_time. | |
683 | * All the past CPU time is accumulated in signal_struct | |
684 | * from sister threads now dead. But in this non-leader | |
685 | * exec, nothing survives from the original leader thread, | |
686 | * whose birth marks the true age of this process now. | |
687 | * When we take on its identity by switching to its PID, we | |
688 | * also take its birthdate (always earlier than our own). | |
689 | */ | |
690 | current->start_time = leader->start_time; | |
691 | ||
1da177e4 LT |
692 | spin_lock(&leader->proc_lock); |
693 | spin_lock(¤t->proc_lock); | |
694 | proc_dentry1 = proc_pid_unhash(current); | |
695 | proc_dentry2 = proc_pid_unhash(leader); | |
696 | write_lock_irq(&tasklist_lock); | |
697 | ||
c2a0f594 LT |
698 | BUG_ON(leader->tgid != current->tgid); |
699 | BUG_ON(current->pid == current->tgid); | |
1da177e4 LT |
700 | /* |
701 | * An exec() starts a new thread group with the | |
702 | * TGID of the previous thread group. Rehash the | |
703 | * two threads with a switched PID, and release | |
704 | * the former thread group leader: | |
705 | */ | |
d73d6529 EB |
706 | |
707 | /* Become a process group leader with the old leader's pid. | |
708 | * Note: The old leader also uses thispid until release_task | |
709 | * is called. Odd but simple and correct. | |
710 | */ | |
711 | detach_pid(current, PIDTYPE_PID); | |
712 | current->pid = leader->pid; | |
713 | attach_pid(current, PIDTYPE_PID, current->pid); | |
714 | attach_pid(current, PIDTYPE_PGID, current->signal->pgrp); | |
715 | attach_pid(current, PIDTYPE_SID, current->signal->session); | |
5e85d4ab | 716 | list_add_tail_rcu(¤t->tasks, &init_task.tasks); |
1da177e4 | 717 | |
1da177e4 | 718 | current->group_leader = current; |
de12a787 EB |
719 | leader->group_leader = current; |
720 | ||
721 | /* Reduce leader to a thread */ | |
722 | detach_pid(leader, PIDTYPE_PGID); | |
723 | detach_pid(leader, PIDTYPE_SID); | |
724 | list_del_init(&leader->tasks); | |
1da177e4 | 725 | |
1da177e4 | 726 | current->exit_signal = SIGCHLD; |
962b564c ON |
727 | |
728 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
729 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
730 | |
731 | write_unlock_irq(&tasklist_lock); | |
732 | spin_unlock(&leader->proc_lock); | |
733 | spin_unlock(¤t->proc_lock); | |
734 | proc_pid_flush(proc_dentry1); | |
735 | proc_pid_flush(proc_dentry2); | |
1da177e4 LT |
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: | |
1da177e4 | 745 | exit_itimers(sig); |
329f7dba ON |
746 | if (leader) |
747 | release_task(leader); | |
748 | ||
749 | BUG_ON(atomic_read(&sig->count) != 1); | |
1da177e4 LT |
750 | |
751 | if (atomic_read(&oldsighand->count) == 1) { | |
752 | /* | |
753 | * Now that we nuked the rest of the thread group, | |
754 | * it turns out we are not sharing sighand any more either. | |
755 | * So we can just keep it. | |
756 | */ | |
757 | kmem_cache_free(sighand_cachep, newsighand); | |
758 | } else { | |
759 | /* | |
760 | * Move our state over to newsighand and switch it in. | |
761 | */ | |
1da177e4 LT |
762 | atomic_set(&newsighand->count, 1); |
763 | memcpy(newsighand->action, oldsighand->action, | |
764 | sizeof(newsighand->action)); | |
765 | ||
766 | write_lock_irq(&tasklist_lock); | |
767 | spin_lock(&oldsighand->siglock); | |
768 | spin_lock(&newsighand->siglock); | |
769 | ||
e56d0903 | 770 | rcu_assign_pointer(current->sighand, newsighand); |
1da177e4 LT |
771 | recalc_sigpending(); |
772 | ||
773 | spin_unlock(&newsighand->siglock); | |
774 | spin_unlock(&oldsighand->siglock); | |
775 | write_unlock_irq(&tasklist_lock); | |
776 | ||
777 | if (atomic_dec_and_test(&oldsighand->count)) | |
aa1757f9 | 778 | kmem_cache_free(sighand_cachep, oldsighand); |
1da177e4 LT |
779 | } |
780 | ||
c2a0f594 | 781 | BUG_ON(!thread_group_leader(current)); |
1da177e4 LT |
782 | return 0; |
783 | } | |
784 | ||
785 | /* | |
786 | * These functions flushes out all traces of the currently running executable | |
787 | * so that a new one can be started | |
788 | */ | |
789 | ||
858119e1 | 790 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
791 | { |
792 | long j = -1; | |
badf1662 | 793 | struct fdtable *fdt; |
1da177e4 LT |
794 | |
795 | spin_lock(&files->file_lock); | |
796 | for (;;) { | |
797 | unsigned long set, i; | |
798 | ||
799 | j++; | |
800 | i = j * __NFDBITS; | |
badf1662 DS |
801 | fdt = files_fdtable(files); |
802 | if (i >= fdt->max_fds || i >= fdt->max_fdset) | |
1da177e4 | 803 | break; |
badf1662 | 804 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
805 | if (!set) |
806 | continue; | |
badf1662 | 807 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
808 | spin_unlock(&files->file_lock); |
809 | for ( ; set ; i++,set >>= 1) { | |
810 | if (set & 1) { | |
811 | sys_close(i); | |
812 | } | |
813 | } | |
814 | spin_lock(&files->file_lock); | |
815 | ||
816 | } | |
817 | spin_unlock(&files->file_lock); | |
818 | } | |
819 | ||
820 | void get_task_comm(char *buf, struct task_struct *tsk) | |
821 | { | |
822 | /* buf must be at least sizeof(tsk->comm) in size */ | |
823 | task_lock(tsk); | |
824 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
825 | task_unlock(tsk); | |
826 | } | |
827 | ||
828 | void set_task_comm(struct task_struct *tsk, char *buf) | |
829 | { | |
830 | task_lock(tsk); | |
831 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); | |
832 | task_unlock(tsk); | |
833 | } | |
834 | ||
835 | int flush_old_exec(struct linux_binprm * bprm) | |
836 | { | |
837 | char * name; | |
838 | int i, ch, retval; | |
839 | struct files_struct *files; | |
840 | char tcomm[sizeof(current->comm)]; | |
841 | ||
842 | /* | |
843 | * Make sure we have a private signal table and that | |
844 | * we are unassociated from the previous thread group. | |
845 | */ | |
846 | retval = de_thread(current); | |
847 | if (retval) | |
848 | goto out; | |
849 | ||
850 | /* | |
851 | * Make sure we have private file handles. Ask the | |
852 | * fork helper to do the work for us and the exit | |
853 | * helper to do the cleanup of the old one. | |
854 | */ | |
855 | files = current->files; /* refcounted so safe to hold */ | |
856 | retval = unshare_files(); | |
857 | if (retval) | |
858 | goto out; | |
859 | /* | |
860 | * Release all of the old mmap stuff | |
861 | */ | |
862 | retval = exec_mmap(bprm->mm); | |
863 | if (retval) | |
864 | goto mmap_failed; | |
865 | ||
866 | bprm->mm = NULL; /* We're using it now */ | |
867 | ||
868 | /* This is the point of no return */ | |
1da177e4 LT |
869 | put_files_struct(files); |
870 | ||
871 | current->sas_ss_sp = current->sas_ss_size = 0; | |
872 | ||
873 | if (current->euid == current->uid && current->egid == current->gid) | |
874 | current->mm->dumpable = 1; | |
d6e71144 AC |
875 | else |
876 | current->mm->dumpable = suid_dumpable; | |
877 | ||
1da177e4 | 878 | name = bprm->filename; |
36772092 PBG |
879 | |
880 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
881 | for (i=0; (ch = *(name++)) != '\0';) { |
882 | if (ch == '/') | |
36772092 | 883 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
884 | else |
885 | if (i < (sizeof(tcomm) - 1)) | |
886 | tcomm[i++] = ch; | |
887 | } | |
888 | tcomm[i] = '\0'; | |
889 | set_task_comm(current, tcomm); | |
890 | ||
891 | current->flags &= ~PF_RANDOMIZE; | |
892 | flush_thread(); | |
893 | ||
0551fbd2 BH |
894 | /* Set the new mm task size. We have to do that late because it may |
895 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
896 | * some architectures like powerpc | |
897 | */ | |
898 | current->mm->task_size = TASK_SIZE; | |
899 | ||
1da177e4 | 900 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || |
8c744fb8 | 901 | file_permission(bprm->file, MAY_READ) || |
1da177e4 LT |
902 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { |
903 | suid_keys(current); | |
d6e71144 | 904 | current->mm->dumpable = suid_dumpable; |
1da177e4 LT |
905 | } |
906 | ||
907 | /* An exec changes our domain. We are no longer part of the thread | |
908 | group */ | |
909 | ||
910 | current->self_exec_id++; | |
911 | ||
912 | flush_signal_handlers(current, 0); | |
913 | flush_old_files(current->files); | |
914 | ||
915 | return 0; | |
916 | ||
917 | mmap_failed: | |
918 | put_files_struct(current->files); | |
919 | current->files = files; | |
920 | out: | |
921 | return retval; | |
922 | } | |
923 | ||
924 | EXPORT_SYMBOL(flush_old_exec); | |
925 | ||
926 | /* | |
927 | * Fill the binprm structure from the inode. | |
928 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
929 | */ | |
930 | int prepare_binprm(struct linux_binprm *bprm) | |
931 | { | |
932 | int mode; | |
933 | struct inode * inode = bprm->file->f_dentry->d_inode; | |
934 | int retval; | |
935 | ||
936 | mode = inode->i_mode; | |
937 | /* | |
938 | * Check execute perms again - if the caller has CAP_DAC_OVERRIDE, | |
939 | * generic_permission lets a non-executable through | |
940 | */ | |
941 | if (!(mode & 0111)) /* with at least _one_ execute bit set */ | |
942 | return -EACCES; | |
943 | if (bprm->file->f_op == NULL) | |
944 | return -EACCES; | |
945 | ||
946 | bprm->e_uid = current->euid; | |
947 | bprm->e_gid = current->egid; | |
948 | ||
949 | if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) { | |
950 | /* Set-uid? */ | |
951 | if (mode & S_ISUID) { | |
952 | current->personality &= ~PER_CLEAR_ON_SETID; | |
953 | bprm->e_uid = inode->i_uid; | |
954 | } | |
955 | ||
956 | /* Set-gid? */ | |
957 | /* | |
958 | * If setgid is set but no group execute bit then this | |
959 | * is a candidate for mandatory locking, not a setgid | |
960 | * executable. | |
961 | */ | |
962 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
963 | current->personality &= ~PER_CLEAR_ON_SETID; | |
964 | bprm->e_gid = inode->i_gid; | |
965 | } | |
966 | } | |
967 | ||
968 | /* fill in binprm security blob */ | |
969 | retval = security_bprm_set(bprm); | |
970 | if (retval) | |
971 | return retval; | |
972 | ||
973 | memset(bprm->buf,0,BINPRM_BUF_SIZE); | |
974 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); | |
975 | } | |
976 | ||
977 | EXPORT_SYMBOL(prepare_binprm); | |
978 | ||
858119e1 | 979 | static int unsafe_exec(struct task_struct *p) |
1da177e4 LT |
980 | { |
981 | int unsafe = 0; | |
982 | if (p->ptrace & PT_PTRACED) { | |
983 | if (p->ptrace & PT_PTRACE_CAP) | |
984 | unsafe |= LSM_UNSAFE_PTRACE_CAP; | |
985 | else | |
986 | unsafe |= LSM_UNSAFE_PTRACE; | |
987 | } | |
988 | if (atomic_read(&p->fs->count) > 1 || | |
989 | atomic_read(&p->files->count) > 1 || | |
990 | atomic_read(&p->sighand->count) > 1) | |
991 | unsafe |= LSM_UNSAFE_SHARE; | |
992 | ||
993 | return unsafe; | |
994 | } | |
995 | ||
996 | void compute_creds(struct linux_binprm *bprm) | |
997 | { | |
998 | int unsafe; | |
999 | ||
1000 | if (bprm->e_uid != current->uid) | |
1001 | suid_keys(current); | |
1002 | exec_keys(current); | |
1003 | ||
1004 | task_lock(current); | |
1005 | unsafe = unsafe_exec(current); | |
1006 | security_bprm_apply_creds(bprm, unsafe); | |
1007 | task_unlock(current); | |
1008 | security_bprm_post_apply_creds(bprm); | |
1009 | } | |
1010 | ||
1011 | EXPORT_SYMBOL(compute_creds); | |
1012 | ||
1013 | void remove_arg_zero(struct linux_binprm *bprm) | |
1014 | { | |
1015 | if (bprm->argc) { | |
1016 | unsigned long offset; | |
1017 | char * kaddr; | |
1018 | struct page *page; | |
1019 | ||
1020 | offset = bprm->p % PAGE_SIZE; | |
1021 | goto inside; | |
1022 | ||
1023 | while (bprm->p++, *(kaddr+offset++)) { | |
1024 | if (offset != PAGE_SIZE) | |
1025 | continue; | |
1026 | offset = 0; | |
1027 | kunmap_atomic(kaddr, KM_USER0); | |
1028 | inside: | |
1029 | page = bprm->page[bprm->p/PAGE_SIZE]; | |
1030 | kaddr = kmap_atomic(page, KM_USER0); | |
1031 | } | |
1032 | kunmap_atomic(kaddr, KM_USER0); | |
1033 | bprm->argc--; | |
1034 | } | |
1035 | } | |
1036 | ||
1037 | EXPORT_SYMBOL(remove_arg_zero); | |
1038 | ||
1039 | /* | |
1040 | * cycle the list of binary formats handler, until one recognizes the image | |
1041 | */ | |
1042 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1043 | { | |
1044 | int try,retval; | |
1045 | struct linux_binfmt *fmt; | |
1046 | #ifdef __alpha__ | |
1047 | /* handle /sbin/loader.. */ | |
1048 | { | |
1049 | struct exec * eh = (struct exec *) bprm->buf; | |
1050 | ||
1051 | if (!bprm->loader && eh->fh.f_magic == 0x183 && | |
1052 | (eh->fh.f_flags & 0x3000) == 0x3000) | |
1053 | { | |
1054 | struct file * file; | |
1055 | unsigned long loader; | |
1056 | ||
1057 | allow_write_access(bprm->file); | |
1058 | fput(bprm->file); | |
1059 | bprm->file = NULL; | |
1060 | ||
1061 | loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); | |
1062 | ||
1063 | file = open_exec("/sbin/loader"); | |
1064 | retval = PTR_ERR(file); | |
1065 | if (IS_ERR(file)) | |
1066 | return retval; | |
1067 | ||
1068 | /* Remember if the application is TASO. */ | |
1069 | bprm->sh_bang = eh->ah.entry < 0x100000000UL; | |
1070 | ||
1071 | bprm->file = file; | |
1072 | bprm->loader = loader; | |
1073 | retval = prepare_binprm(bprm); | |
1074 | if (retval<0) | |
1075 | return retval; | |
1076 | /* should call search_binary_handler recursively here, | |
1077 | but it does not matter */ | |
1078 | } | |
1079 | } | |
1080 | #endif | |
1081 | retval = security_bprm_check(bprm); | |
1082 | if (retval) | |
1083 | return retval; | |
1084 | ||
1085 | /* kernel module loader fixup */ | |
1086 | /* so we don't try to load run modprobe in kernel space. */ | |
1087 | set_fs(USER_DS); | |
473ae30b AV |
1088 | |
1089 | retval = audit_bprm(bprm); | |
1090 | if (retval) | |
1091 | return retval; | |
1092 | ||
1da177e4 LT |
1093 | retval = -ENOENT; |
1094 | for (try=0; try<2; try++) { | |
1095 | read_lock(&binfmt_lock); | |
1096 | for (fmt = formats ; fmt ; fmt = fmt->next) { | |
1097 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; | |
1098 | if (!fn) | |
1099 | continue; | |
1100 | if (!try_module_get(fmt->module)) | |
1101 | continue; | |
1102 | read_unlock(&binfmt_lock); | |
1103 | retval = fn(bprm, regs); | |
1104 | if (retval >= 0) { | |
1105 | put_binfmt(fmt); | |
1106 | allow_write_access(bprm->file); | |
1107 | if (bprm->file) | |
1108 | fput(bprm->file); | |
1109 | bprm->file = NULL; | |
1110 | current->did_exec = 1; | |
9f46080c | 1111 | proc_exec_connector(current); |
1da177e4 LT |
1112 | return retval; |
1113 | } | |
1114 | read_lock(&binfmt_lock); | |
1115 | put_binfmt(fmt); | |
1116 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1117 | break; | |
1118 | if (!bprm->file) { | |
1119 | read_unlock(&binfmt_lock); | |
1120 | return retval; | |
1121 | } | |
1122 | } | |
1123 | read_unlock(&binfmt_lock); | |
1124 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1125 | break; | |
1126 | #ifdef CONFIG_KMOD | |
1127 | }else{ | |
1128 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) | |
1129 | if (printable(bprm->buf[0]) && | |
1130 | printable(bprm->buf[1]) && | |
1131 | printable(bprm->buf[2]) && | |
1132 | printable(bprm->buf[3])) | |
1133 | break; /* -ENOEXEC */ | |
1134 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1135 | #endif | |
1136 | } | |
1137 | } | |
1138 | return retval; | |
1139 | } | |
1140 | ||
1141 | EXPORT_SYMBOL(search_binary_handler); | |
1142 | ||
1143 | /* | |
1144 | * sys_execve() executes a new program. | |
1145 | */ | |
1146 | int do_execve(char * filename, | |
1147 | char __user *__user *argv, | |
1148 | char __user *__user *envp, | |
1149 | struct pt_regs * regs) | |
1150 | { | |
1151 | struct linux_binprm *bprm; | |
1152 | struct file *file; | |
1153 | int retval; | |
1154 | int i; | |
1155 | ||
1156 | retval = -ENOMEM; | |
11b0b5ab | 1157 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 LT |
1158 | if (!bprm) |
1159 | goto out_ret; | |
1da177e4 LT |
1160 | |
1161 | file = open_exec(filename); | |
1162 | retval = PTR_ERR(file); | |
1163 | if (IS_ERR(file)) | |
1164 | goto out_kfree; | |
1165 | ||
1166 | sched_exec(); | |
1167 | ||
1168 | bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); | |
1169 | ||
1170 | bprm->file = file; | |
1171 | bprm->filename = filename; | |
1172 | bprm->interp = filename; | |
1173 | bprm->mm = mm_alloc(); | |
1174 | retval = -ENOMEM; | |
1175 | if (!bprm->mm) | |
1176 | goto out_file; | |
1177 | ||
1178 | retval = init_new_context(current, bprm->mm); | |
1179 | if (retval < 0) | |
1180 | goto out_mm; | |
1181 | ||
1182 | bprm->argc = count(argv, bprm->p / sizeof(void *)); | |
1183 | if ((retval = bprm->argc) < 0) | |
1184 | goto out_mm; | |
1185 | ||
1186 | bprm->envc = count(envp, bprm->p / sizeof(void *)); | |
1187 | if ((retval = bprm->envc) < 0) | |
1188 | goto out_mm; | |
1189 | ||
1190 | retval = security_bprm_alloc(bprm); | |
1191 | if (retval) | |
1192 | goto out; | |
1193 | ||
1194 | retval = prepare_binprm(bprm); | |
1195 | if (retval < 0) | |
1196 | goto out; | |
1197 | ||
1198 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1199 | if (retval < 0) | |
1200 | goto out; | |
1201 | ||
1202 | bprm->exec = bprm->p; | |
1203 | retval = copy_strings(bprm->envc, envp, bprm); | |
1204 | if (retval < 0) | |
1205 | goto out; | |
1206 | ||
1207 | retval = copy_strings(bprm->argc, argv, bprm); | |
1208 | if (retval < 0) | |
1209 | goto out; | |
1210 | ||
1211 | retval = search_binary_handler(bprm,regs); | |
1212 | if (retval >= 0) { | |
1213 | free_arg_pages(bprm); | |
1214 | ||
1215 | /* execve success */ | |
1216 | security_bprm_free(bprm); | |
1217 | acct_update_integrals(current); | |
1da177e4 LT |
1218 | kfree(bprm); |
1219 | return retval; | |
1220 | } | |
1221 | ||
1222 | out: | |
1223 | /* Something went wrong, return the inode and free the argument pages*/ | |
1224 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) { | |
1225 | struct page * page = bprm->page[i]; | |
1226 | if (page) | |
1227 | __free_page(page); | |
1228 | } | |
1229 | ||
1230 | if (bprm->security) | |
1231 | security_bprm_free(bprm); | |
1232 | ||
1233 | out_mm: | |
1234 | if (bprm->mm) | |
1235 | mmdrop(bprm->mm); | |
1236 | ||
1237 | out_file: | |
1238 | if (bprm->file) { | |
1239 | allow_write_access(bprm->file); | |
1240 | fput(bprm->file); | |
1241 | } | |
1242 | ||
1243 | out_kfree: | |
1244 | kfree(bprm); | |
1245 | ||
1246 | out_ret: | |
1247 | return retval; | |
1248 | } | |
1249 | ||
1250 | int set_binfmt(struct linux_binfmt *new) | |
1251 | { | |
1252 | struct linux_binfmt *old = current->binfmt; | |
1253 | ||
1254 | if (new) { | |
1255 | if (!try_module_get(new->module)) | |
1256 | return -1; | |
1257 | } | |
1258 | current->binfmt = new; | |
1259 | if (old) | |
1260 | module_put(old->module); | |
1261 | return 0; | |
1262 | } | |
1263 | ||
1264 | EXPORT_SYMBOL(set_binfmt); | |
1265 | ||
1266 | #define CORENAME_MAX_SIZE 64 | |
1267 | ||
1268 | /* format_corename will inspect the pattern parameter, and output a | |
1269 | * name into corename, which must have space for at least | |
1270 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1271 | */ | |
1272 | static void format_corename(char *corename, const char *pattern, long signr) | |
1273 | { | |
1274 | const char *pat_ptr = pattern; | |
1275 | char *out_ptr = corename; | |
1276 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1277 | int rc; | |
1278 | int pid_in_pattern = 0; | |
1279 | ||
1280 | /* Repeat as long as we have more pattern to process and more output | |
1281 | space */ | |
1282 | while (*pat_ptr) { | |
1283 | if (*pat_ptr != '%') { | |
1284 | if (out_ptr == out_end) | |
1285 | goto out; | |
1286 | *out_ptr++ = *pat_ptr++; | |
1287 | } else { | |
1288 | switch (*++pat_ptr) { | |
1289 | case 0: | |
1290 | goto out; | |
1291 | /* Double percent, output one percent */ | |
1292 | case '%': | |
1293 | if (out_ptr == out_end) | |
1294 | goto out; | |
1295 | *out_ptr++ = '%'; | |
1296 | break; | |
1297 | /* pid */ | |
1298 | case 'p': | |
1299 | pid_in_pattern = 1; | |
1300 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1301 | "%d", current->tgid); | |
1302 | if (rc > out_end - out_ptr) | |
1303 | goto out; | |
1304 | out_ptr += rc; | |
1305 | break; | |
1306 | /* uid */ | |
1307 | case 'u': | |
1308 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1309 | "%d", current->uid); | |
1310 | if (rc > out_end - out_ptr) | |
1311 | goto out; | |
1312 | out_ptr += rc; | |
1313 | break; | |
1314 | /* gid */ | |
1315 | case 'g': | |
1316 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1317 | "%d", current->gid); | |
1318 | if (rc > out_end - out_ptr) | |
1319 | goto out; | |
1320 | out_ptr += rc; | |
1321 | break; | |
1322 | /* signal that caused the coredump */ | |
1323 | case 's': | |
1324 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1325 | "%ld", signr); | |
1326 | if (rc > out_end - out_ptr) | |
1327 | goto out; | |
1328 | out_ptr += rc; | |
1329 | break; | |
1330 | /* UNIX time of coredump */ | |
1331 | case 't': { | |
1332 | struct timeval tv; | |
1333 | do_gettimeofday(&tv); | |
1334 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1335 | "%lu", tv.tv_sec); | |
1336 | if (rc > out_end - out_ptr) | |
1337 | goto out; | |
1338 | out_ptr += rc; | |
1339 | break; | |
1340 | } | |
1341 | /* hostname */ | |
1342 | case 'h': | |
1343 | down_read(&uts_sem); | |
1344 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1345 | "%s", system_utsname.nodename); | |
1346 | up_read(&uts_sem); | |
1347 | if (rc > out_end - out_ptr) | |
1348 | goto out; | |
1349 | out_ptr += rc; | |
1350 | break; | |
1351 | /* executable */ | |
1352 | case 'e': | |
1353 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1354 | "%s", current->comm); | |
1355 | if (rc > out_end - out_ptr) | |
1356 | goto out; | |
1357 | out_ptr += rc; | |
1358 | break; | |
1359 | default: | |
1360 | break; | |
1361 | } | |
1362 | ++pat_ptr; | |
1363 | } | |
1364 | } | |
1365 | /* Backward compatibility with core_uses_pid: | |
1366 | * | |
1367 | * If core_pattern does not include a %p (as is the default) | |
1368 | * and core_uses_pid is set, then .%pid will be appended to | |
1369 | * the filename */ | |
1370 | if (!pid_in_pattern | |
1371 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { | |
1372 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1373 | ".%d", current->tgid); | |
1374 | if (rc > out_end - out_ptr) | |
1375 | goto out; | |
1376 | out_ptr += rc; | |
1377 | } | |
1378 | out: | |
1379 | *out_ptr = 0; | |
1380 | } | |
1381 | ||
1382 | static void zap_threads (struct mm_struct *mm) | |
1383 | { | |
1384 | struct task_struct *g, *p; | |
1385 | struct task_struct *tsk = current; | |
1386 | struct completion *vfork_done = tsk->vfork_done; | |
1387 | int traced = 0; | |
1388 | ||
1389 | /* | |
1390 | * Make sure nobody is waiting for us to release the VM, | |
1391 | * otherwise we can deadlock when we wait on each other | |
1392 | */ | |
1393 | if (vfork_done) { | |
1394 | tsk->vfork_done = NULL; | |
1395 | complete(vfork_done); | |
1396 | } | |
1397 | ||
1398 | read_lock(&tasklist_lock); | |
1399 | do_each_thread(g,p) | |
1400 | if (mm == p->mm && p != tsk) { | |
1401 | force_sig_specific(SIGKILL, p); | |
1402 | mm->core_waiters++; | |
1403 | if (unlikely(p->ptrace) && | |
1404 | unlikely(p->parent->mm == mm)) | |
1405 | traced = 1; | |
1406 | } | |
1407 | while_each_thread(g,p); | |
1408 | ||
1409 | read_unlock(&tasklist_lock); | |
1410 | ||
1411 | if (unlikely(traced)) { | |
1412 | /* | |
1413 | * We are zapping a thread and the thread it ptraces. | |
1414 | * If the tracee went into a ptrace stop for exit tracing, | |
1415 | * we could deadlock since the tracer is waiting for this | |
1416 | * coredump to finish. Detach them so they can both die. | |
1417 | */ | |
1418 | write_lock_irq(&tasklist_lock); | |
1419 | do_each_thread(g,p) { | |
1420 | if (mm == p->mm && p != tsk && | |
1421 | p->ptrace && p->parent->mm == mm) { | |
5ecfbae0 | 1422 | __ptrace_detach(p, 0); |
1da177e4 LT |
1423 | } |
1424 | } while_each_thread(g,p); | |
1425 | write_unlock_irq(&tasklist_lock); | |
1426 | } | |
1427 | } | |
1428 | ||
1429 | static void coredump_wait(struct mm_struct *mm) | |
1430 | { | |
1431 | DECLARE_COMPLETION(startup_done); | |
2384f55f | 1432 | int core_waiters; |
1da177e4 | 1433 | |
1da177e4 LT |
1434 | mm->core_startup_done = &startup_done; |
1435 | ||
1da177e4 | 1436 | zap_threads(mm); |
2384f55f ON |
1437 | core_waiters = mm->core_waiters; |
1438 | up_write(&mm->mmap_sem); | |
1439 | ||
1440 | if (core_waiters) | |
1da177e4 | 1441 | wait_for_completion(&startup_done); |
1da177e4 LT |
1442 | BUG_ON(mm->core_waiters); |
1443 | } | |
1444 | ||
1445 | int do_coredump(long signr, int exit_code, struct pt_regs * regs) | |
1446 | { | |
1447 | char corename[CORENAME_MAX_SIZE + 1]; | |
1448 | struct mm_struct *mm = current->mm; | |
1449 | struct linux_binfmt * binfmt; | |
1450 | struct inode * inode; | |
1451 | struct file * file; | |
1452 | int retval = 0; | |
d6e71144 AC |
1453 | int fsuid = current->fsuid; |
1454 | int flag = 0; | |
1da177e4 LT |
1455 | |
1456 | binfmt = current->binfmt; | |
1457 | if (!binfmt || !binfmt->core_dump) | |
1458 | goto fail; | |
1459 | down_write(&mm->mmap_sem); | |
1460 | if (!mm->dumpable) { | |
1461 | up_write(&mm->mmap_sem); | |
1462 | goto fail; | |
1463 | } | |
d6e71144 AC |
1464 | |
1465 | /* | |
1466 | * We cannot trust fsuid as being the "true" uid of the | |
1467 | * process nor do we know its entire history. We only know it | |
1468 | * was tainted so we dump it as root in mode 2. | |
1469 | */ | |
1470 | if (mm->dumpable == 2) { /* Setuid core dump mode */ | |
1471 | flag = O_EXCL; /* Stop rewrite attacks */ | |
1472 | current->fsuid = 0; /* Dump root private */ | |
1473 | } | |
1da177e4 | 1474 | mm->dumpable = 0; |
1291cf41 ON |
1475 | |
1476 | retval = -EAGAIN; | |
1da177e4 | 1477 | spin_lock_irq(¤t->sighand->siglock); |
1291cf41 ON |
1478 | if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) { |
1479 | current->signal->flags = SIGNAL_GROUP_EXIT; | |
1480 | current->signal->group_exit_code = exit_code; | |
bb6f6dba | 1481 | current->signal->group_stop_count = 0; |
1291cf41 ON |
1482 | retval = 0; |
1483 | } | |
1da177e4 | 1484 | spin_unlock_irq(¤t->sighand->siglock); |
1291cf41 ON |
1485 | if (retval) { |
1486 | up_write(&mm->mmap_sem); | |
1487 | goto fail; | |
1488 | } | |
1489 | ||
1490 | init_completion(&mm->core_done); | |
1da177e4 LT |
1491 | coredump_wait(mm); |
1492 | ||
1493 | /* | |
1494 | * Clear any false indication of pending signals that might | |
1495 | * be seen by the filesystem code called to write the core file. | |
1496 | */ | |
1da177e4 LT |
1497 | clear_thread_flag(TIF_SIGPENDING); |
1498 | ||
1499 | if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) | |
1500 | goto fail_unlock; | |
1501 | ||
1502 | /* | |
1503 | * lock_kernel() because format_corename() is controlled by sysctl, which | |
1504 | * uses lock_kernel() | |
1505 | */ | |
1506 | lock_kernel(); | |
1507 | format_corename(corename, core_pattern, signr); | |
1508 | unlock_kernel(); | |
d6e71144 | 1509 | file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600); |
1da177e4 LT |
1510 | if (IS_ERR(file)) |
1511 | goto fail_unlock; | |
1512 | inode = file->f_dentry->d_inode; | |
1513 | if (inode->i_nlink > 1) | |
1514 | goto close_fail; /* multiple links - don't dump */ | |
1515 | if (d_unhashed(file->f_dentry)) | |
1516 | goto close_fail; | |
1517 | ||
1518 | if (!S_ISREG(inode->i_mode)) | |
1519 | goto close_fail; | |
1520 | if (!file->f_op) | |
1521 | goto close_fail; | |
1522 | if (!file->f_op->write) | |
1523 | goto close_fail; | |
4a30131e | 1524 | if (do_truncate(file->f_dentry, 0, 0, file) != 0) |
1da177e4 LT |
1525 | goto close_fail; |
1526 | ||
1527 | retval = binfmt->core_dump(signr, regs, file); | |
1528 | ||
1529 | if (retval) | |
1530 | current->signal->group_exit_code |= 0x80; | |
1531 | close_fail: | |
1532 | filp_close(file, NULL); | |
1533 | fail_unlock: | |
d6e71144 | 1534 | current->fsuid = fsuid; |
1da177e4 LT |
1535 | complete_all(&mm->core_done); |
1536 | fail: | |
1537 | return retval; | |
1538 | } |