blob: 0b88bf646143c983a36309c3d5f425dcff7ec841 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Matt Helsley9f460802005-11-07 00:59:16 -080051#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040052#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54#include <asm/uaccess.h>
55#include <asm/mmu_context.h>
56
57#ifdef CONFIG_KMOD
58#include <linux/kmod.h>
59#endif
60
61int core_uses_pid;
62char core_pattern[65] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070063int suid_dumpable = 0;
64
65EXPORT_SYMBOL(suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066/* The maximal length of core_pattern is also specified in sysctl.c */
67
68static struct linux_binfmt *formats;
69static DEFINE_RWLOCK(binfmt_lock);
70
71int 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
93EXPORT_SYMBOL(register_binfmt);
94
95int 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
112EXPORT_SYMBOL(unregister_binfmt);
113
114static 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 */
125asmlinkage long sys_uselib(const char __user * library)
126{
127 struct file * file;
128 struct nameidata nd;
129 int error;
130
Oleg Drokinb5005312006-03-25 03:07:01 -0800131 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 if (error)
133 goto out;
134
135 error = -EINVAL;
136 if (!S_ISREG(nd.dentry->d_inode->i_mode))
137 goto exit;
138
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800139 error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 if (error)
141 goto exit;
142
Trond Myklebust834f2a42005-10-18 14:20:16 -0700143 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 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);
168out:
169 return error;
170exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700171 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 path_release(&nd);
173 goto out;
174}
175
176/*
177 * count() counts the number of strings in array ARGV.
178 */
179static 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 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700205static int copy_strings(int argc, char __user * __user * argv,
206 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
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;
278out:
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 */
287int 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
297EXPORT_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 */
306void install_arg_page(struct vm_area_struct *vma,
307 struct page *page, unsigned long address)
308{
309 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 pte_t * pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700311 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
313 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickinsc74df322005-10-29 18:16:23 -0700314 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -0800317 pte = get_locked_pte(mm, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 if (!pte)
319 goto out;
320 if (!pte_none(*pte)) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700321 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 goto out;
323 }
Hugh Dickins42946212005-10-29 18:16:05 -0700324 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 lru_cache_add_active(page);
326 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
327 page, vma->vm_page_prot))));
Nick Piggin9617d952006-01-06 00:11:12 -0800328 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700329 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
331 /* no need for flush_tlb */
332 return;
333out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 __free_page(page);
335 force_sig(SIGKILL, current);
336}
337
338#define EXTRA_STACK_VM_PAGES 20 /* random */
339
340int 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 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
456EXPORT_SYMBOL(setup_arg_pages);
457
458#define free_arg_pages(bprm) do { } while (0)
459
460#else
461
462static 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
475struct file *open_exec(const char *name)
476{
477 struct nameidata nd;
478 int err;
479 struct file *file;
480
Oleg Drokinb5005312006-03-25 03:07:01 -0800481 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 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)) {
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800489 int err = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 if (!err && !(inode->i_mode & 0111))
491 err = -EACCES;
492 file = ERR_PTR(err);
493 if (!err) {
Trond Myklebust834f2a42005-10-18 14:20:16 -0700494 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 if (!IS_ERR(file)) {
496 err = deny_write_access(file);
497 if (err) {
498 fput(file);
499 file = ERR_PTR(err);
500 }
501 }
502out:
503 return file;
504 }
505 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700506 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 path_release(&nd);
508 }
509 goto out;
510}
511
512EXPORT_SYMBOL(open_exec);
513
514int 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
529EXPORT_SYMBOL(kernel_read);
530
531static 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);
Eric Sesterhenn7dddb122006-04-01 01:13:38 +0200565 BUG_ON(active_mm != old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 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 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800579static int de_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
581 struct signal_struct *sig = tsk->signal;
582 struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
583 spinlock_t *lock = &oldsighand->siglock;
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300584 struct task_struct *leader = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 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 }
Oleg Nesterov14342612006-03-28 16:10:59 -0800620
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 zap_other_threads(current);
630 read_unlock(&tasklist_lock);
631
632 /*
633 * Account for the thread group leader hanging around:
634 */
Oleg Nesterov9e4e23b2005-10-30 15:01:37 -0800635 count = 1;
636 if (!thread_group_leader(current)) {
637 count = 2;
Roland McGrath53231252005-07-12 13:58:27 -0700638 /*
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 */
Roman Zippel05cfb612006-03-26 01:38:12 -0800645 sig->tsk = current;
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800646 spin_unlock_irq(lock);
Thomas Gleixner2ff678b2006-01-09 20:52:34 -0800647 if (hrtimer_cancel(&sig->real_timer))
648 hrtimer_restart(&sig->real_timer);
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800649 spin_lock_irq(lock);
Roland McGrath53231252005-07-12 13:58:27 -0700650 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 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)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 struct dentry *proc_dentry1, *proc_dentry2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
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 */
Oleg Nesterov14342612006-03-28 16:10:59 -0800676 leader = current->group_leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 while (leader->exit_state != EXIT_ZOMBIE)
678 yield();
679
Roland McGrathf5e90282006-04-10 22:54:16 -0700680 /*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 spin_lock(&leader->proc_lock);
693 spin_lock(&current->proc_lock);
694 proc_dentry1 = proc_pid_unhash(current);
695 proc_dentry2 = proc_pid_unhash(leader);
696 write_lock_irq(&tasklist_lock);
697
Linus Torvaldsc2a0f592005-06-18 13:06:22 -0700698 BUG_ON(leader->tgid != current->tgid);
699 BUG_ON(current->pid == current->tgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 /*
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 */
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800706
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);
Eric W. Biederman5e85d4a2006-04-18 22:20:16 -0700716 list_add_tail_rcu(&current->tasks, &init_task.tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 current->group_leader = current;
Eric W. Biedermande12a782006-04-10 17:16:49 -0600719 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 current->exit_signal = SIGCHLD;
Oleg Nesterov962b5642005-11-23 13:37:43 -0800727
728 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
729 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
731 write_unlock_irq(&tasklist_lock);
732 spin_unlock(&leader->proc_lock);
733 spin_unlock(&current->proc_lock);
734 proc_pid_flush(proc_dentry1);
735 proc_pid_flush(proc_dentry2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 }
737
738 /*
Alexander Nybergfb085cf2005-09-14 18:54:06 +0200739 * There may be one thread left which is just exiting,
740 * but it's safe to stop telling the group to kill themselves.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 */
742 sig->flags = 0;
743
744no_thread_group:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 exit_itimers(sig);
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300746 if (leader)
747 release_task(leader);
748
749 BUG_ON(atomic_read(&sig->count) != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 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
Ingo Molnare56d0902006-01-08 01:01:37 -0800770 rcu_assign_pointer(current->sighand, newsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 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))
Oleg Nesterovaa1757f2006-03-28 16:11:12 -0800778 kmem_cache_free(sighand_cachep, oldsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 }
780
Linus Torvaldsc2a0f592005-06-18 13:06:22 -0700781 BUG_ON(!thread_group_leader(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 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
Arjan van de Ven858119e2006-01-14 13:20:43 -0800790static void flush_old_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791{
792 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700793 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794
795 spin_lock(&files->file_lock);
796 for (;;) {
797 unsigned long set, i;
798
799 j++;
800 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700801 fdt = files_fdtable(files);
802 if (i >= fdt->max_fds || i >= fdt->max_fdset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700804 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 if (!set)
806 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700807 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 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
820void 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
828void 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
835int 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 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;
Alan Coxd6e71142005-06-23 00:09:43 -0700875 else
876 current->mm->dumpable = suid_dumpable;
877
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700879
880 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 for (i=0; (ch = *(name++)) != '\0';) {
882 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700883 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 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
Benjamin Herrenschmidt0551fbd2006-02-28 16:59:19 -0800894 /* 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800901 file_permission(bprm->file, MAY_READ) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
903 suid_keys(current);
Alan Coxd6e71142005-06-23 00:09:43 -0700904 current->mm->dumpable = suid_dumpable;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 }
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
917mmap_failed:
918 put_files_struct(current->files);
919 current->files = files;
920out:
921 return retval;
922}
923
924EXPORT_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 */
930int 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
977EXPORT_SYMBOL(prepare_binprm);
978
Arjan van de Ven858119e2006-01-14 13:20:43 -0800979static int unsafe_exec(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980{
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
996void 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
1011EXPORT_SYMBOL(compute_creds);
1012
1013void 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);
1028inside:
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
1037EXPORT_SYMBOL(remove_arg_zero);
1038
1039/*
1040 * cycle the list of binary formats handler, until one recognizes the image
1041 */
1042int 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);
Al Viro473ae302006-04-26 14:04:08 -04001088
1089 retval = audit_bprm(bprm);
1090 if (retval)
1091 return retval;
1092
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 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;
Matt Helsley9f460802005-11-07 00:59:16 -08001111 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 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
1141EXPORT_SYMBOL(search_binary_handler);
1142
1143/*
1144 * sys_execve() executes a new program.
1145 */
1146int 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;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001157 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 if (!bprm)
1159 goto out_ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160
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);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 kfree(bprm);
1219 return retval;
1220 }
1221
1222out:
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
1233out_mm:
1234 if (bprm->mm)
1235 mmdrop(bprm->mm);
1236
1237out_file:
1238 if (bprm->file) {
1239 allow_write_access(bprm->file);
1240 fput(bprm->file);
1241 }
1242
1243out_kfree:
1244 kfree(bprm);
1245
1246out_ret:
1247 return retval;
1248}
1249
1250int 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
1264EXPORT_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 */
1272static 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(&current->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
1382static 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) {
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +03001422 __ptrace_detach(p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 }
1424 } while_each_thread(g,p);
1425 write_unlock_irq(&tasklist_lock);
1426 }
1427}
1428
1429static void coredump_wait(struct mm_struct *mm)
1430{
1431 DECLARE_COMPLETION(startup_done);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001432 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434 mm->core_startup_done = &startup_done;
1435
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436 zap_threads(mm);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001437 core_waiters = mm->core_waiters;
1438 up_write(&mm->mmap_sem);
1439
1440 if (core_waiters)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 wait_for_completion(&startup_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 BUG_ON(mm->core_waiters);
1443}
1444
1445int 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;
Alan Coxd6e71142005-06-23 00:09:43 -07001453 int fsuid = current->fsuid;
1454 int flag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455
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 }
Alan Coxd6e71142005-06-23 00:09:43 -07001464
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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 mm->dumpable = 0;
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001475
1476 retval = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001478 if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
1479 current->signal->flags = SIGNAL_GROUP_EXIT;
1480 current->signal->group_exit_code = exit_code;
Oleg Nesterovbb6f6db2006-01-08 01:03:13 -08001481 current->signal->group_stop_count = 0;
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001482 retval = 0;
1483 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 spin_unlock_irq(&current->sighand->siglock);
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001485 if (retval) {
1486 up_write(&mm->mmap_sem);
1487 goto fail;
1488 }
1489
1490 init_completion(&mm->core_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 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();
Alan Coxd6e71142005-06-23 00:09:43 -07001509 file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 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;
NeilBrown4a301312006-01-08 01:02:39 -08001524 if (do_truncate(file->f_dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525 goto close_fail;
1526
1527 retval = binfmt->core_dump(signr, regs, file);
1528
1529 if (retval)
1530 current->signal->group_exit_code |= 0x80;
1531close_fail:
1532 filp_close(file, NULL);
1533fail_unlock:
Alan Coxd6e71142005-06-23 00:09:43 -07001534 current->fsuid = fsuid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535 complete_all(&mm->core_done);
1536fail:
1537 return retval;
1538}