blob: 0db3fc3c5f0fe713af2d9a515c7cfdc7670d0223 [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
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/slab.h>
26#include <linux/file.h>
27#include <linux/mman.h>
28#include <linux/a.out.h>
29#include <linux/stat.h>
30#include <linux/fcntl.h>
31#include <linux/smp_lock.h>
32#include <linux/init.h>
33#include <linux/pagemap.h>
34#include <linux/highmem.h>
35#include <linux/spinlock.h>
36#include <linux/key.h>
37#include <linux/personality.h>
38#include <linux/binfmts.h>
39#include <linux/swap.h>
40#include <linux/utsname.h>
41#include <linux/module.h>
42#include <linux/namei.h>
43#include <linux/proc_fs.h>
44#include <linux/ptrace.h>
45#include <linux/mount.h>
46#include <linux/security.h>
47#include <linux/syscalls.h>
48#include <linux/rmap.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070049#include <linux/tsacct_kern.h>
Matt Helsley9f460802005-11-07 00:59:16 -080050#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040051#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#include <asm/uaccess.h>
54#include <asm/mmu_context.h>
55
56#ifdef CONFIG_KMOD
57#include <linux/kmod.h>
58#endif
59
60int core_uses_pid;
61char core_pattern[65] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070062int suid_dumpable = 0;
63
64EXPORT_SYMBOL(suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065/* The maximal length of core_pattern is also specified in sysctl.c */
66
67static struct linux_binfmt *formats;
68static DEFINE_RWLOCK(binfmt_lock);
69
70int register_binfmt(struct linux_binfmt * fmt)
71{
72 struct linux_binfmt ** tmp = &formats;
73
74 if (!fmt)
75 return -EINVAL;
76 if (fmt->next)
77 return -EBUSY;
78 write_lock(&binfmt_lock);
79 while (*tmp) {
80 if (fmt == *tmp) {
81 write_unlock(&binfmt_lock);
82 return -EBUSY;
83 }
84 tmp = &(*tmp)->next;
85 }
86 fmt->next = formats;
87 formats = fmt;
88 write_unlock(&binfmt_lock);
89 return 0;
90}
91
92EXPORT_SYMBOL(register_binfmt);
93
94int unregister_binfmt(struct linux_binfmt * fmt)
95{
96 struct linux_binfmt ** tmp = &formats;
97
98 write_lock(&binfmt_lock);
99 while (*tmp) {
100 if (fmt == *tmp) {
101 *tmp = fmt->next;
102 write_unlock(&binfmt_lock);
103 return 0;
104 }
105 tmp = &(*tmp)->next;
106 }
107 write_unlock(&binfmt_lock);
108 return -EINVAL;
109}
110
111EXPORT_SYMBOL(unregister_binfmt);
112
113static inline void put_binfmt(struct linux_binfmt * fmt)
114{
115 module_put(fmt->module);
116}
117
118/*
119 * Note that a shared library must be both readable and executable due to
120 * security reasons.
121 *
122 * Also note that we take the address to load from from the file itself.
123 */
124asmlinkage long sys_uselib(const char __user * library)
125{
126 struct file * file;
127 struct nameidata nd;
128 int error;
129
Oleg Drokinb5005312006-03-25 03:07:01 -0800130 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (error)
132 goto out;
133
134 error = -EINVAL;
135 if (!S_ISREG(nd.dentry->d_inode->i_mode))
136 goto exit;
137
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800138 error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 if (error)
140 goto exit;
141
Trond Myklebust834f2a42005-10-18 14:20:16 -0700142 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 error = PTR_ERR(file);
144 if (IS_ERR(file))
145 goto out;
146
147 error = -ENOEXEC;
148 if(file->f_op) {
149 struct linux_binfmt * fmt;
150
151 read_lock(&binfmt_lock);
152 for (fmt = formats ; fmt ; fmt = fmt->next) {
153 if (!fmt->load_shlib)
154 continue;
155 if (!try_module_get(fmt->module))
156 continue;
157 read_unlock(&binfmt_lock);
158 error = fmt->load_shlib(file);
159 read_lock(&binfmt_lock);
160 put_binfmt(fmt);
161 if (error != -ENOEXEC)
162 break;
163 }
164 read_unlock(&binfmt_lock);
165 }
166 fput(file);
167out:
168 return error;
169exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700170 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 path_release(&nd);
172 goto out;
173}
174
175/*
176 * count() counts the number of strings in array ARGV.
177 */
178static int count(char __user * __user * argv, int max)
179{
180 int i = 0;
181
182 if (argv != NULL) {
183 for (;;) {
184 char __user * p;
185
186 if (get_user(p, argv))
187 return -EFAULT;
188 if (!p)
189 break;
190 argv++;
191 if(++i > max)
192 return -E2BIG;
193 cond_resched();
194 }
195 }
196 return i;
197}
198
199/*
200 * 'copy_strings()' copies argument/environment strings from user
201 * memory to free pages in kernel mem. These are in a format ready
202 * to be put directly into the top of new user memory.
203 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700204static int copy_strings(int argc, char __user * __user * argv,
205 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
207 struct page *kmapped_page = NULL;
208 char *kaddr = NULL;
209 int ret;
210
211 while (argc-- > 0) {
212 char __user *str;
213 int len;
214 unsigned long pos;
215
216 if (get_user(str, argv+argc) ||
217 !(len = strnlen_user(str, bprm->p))) {
218 ret = -EFAULT;
219 goto out;
220 }
221
222 if (bprm->p < len) {
223 ret = -E2BIG;
224 goto out;
225 }
226
227 bprm->p -= len;
228 /* XXX: add architecture specific overflow check here. */
229 pos = bprm->p;
230
231 while (len > 0) {
232 int i, new, err;
233 int offset, bytes_to_copy;
234 struct page *page;
235
236 offset = pos % PAGE_SIZE;
237 i = pos/PAGE_SIZE;
238 page = bprm->page[i];
239 new = 0;
240 if (!page) {
241 page = alloc_page(GFP_HIGHUSER);
242 bprm->page[i] = page;
243 if (!page) {
244 ret = -ENOMEM;
245 goto out;
246 }
247 new = 1;
248 }
249
250 if (page != kmapped_page) {
251 if (kmapped_page)
252 kunmap(kmapped_page);
253 kmapped_page = page;
254 kaddr = kmap(kmapped_page);
255 }
256 if (new && offset)
257 memset(kaddr, 0, offset);
258 bytes_to_copy = PAGE_SIZE - offset;
259 if (bytes_to_copy > len) {
260 bytes_to_copy = len;
261 if (new)
262 memset(kaddr+offset+len, 0,
263 PAGE_SIZE-offset-len);
264 }
265 err = copy_from_user(kaddr+offset, str, bytes_to_copy);
266 if (err) {
267 ret = -EFAULT;
268 goto out;
269 }
270
271 pos += bytes_to_copy;
272 str += bytes_to_copy;
273 len -= bytes_to_copy;
274 }
275 }
276 ret = 0;
277out:
278 if (kmapped_page)
279 kunmap(kmapped_page);
280 return ret;
281}
282
283/*
284 * Like copy_strings, but get argv and its values from kernel memory.
285 */
286int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
287{
288 int r;
289 mm_segment_t oldfs = get_fs();
290 set_fs(KERNEL_DS);
291 r = copy_strings(argc, (char __user * __user *)argv, bprm);
292 set_fs(oldfs);
293 return r;
294}
295
296EXPORT_SYMBOL(copy_strings_kernel);
297
298#ifdef CONFIG_MMU
299/*
300 * This routine is used to map in a page into an address space: needed by
301 * execve() for the initial stack and environment pages.
302 *
303 * vma->vm_mm->mmap_sem is held for writing.
304 */
305void install_arg_page(struct vm_area_struct *vma,
306 struct page *page, unsigned long address)
307{
308 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 pte_t * pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700310 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
312 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickinsc74df322005-10-29 18:16:23 -0700313 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314
315 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -0800316 pte = get_locked_pte(mm, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 if (!pte)
318 goto out;
319 if (!pte_none(*pte)) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700320 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 goto out;
322 }
Hugh Dickins42946212005-10-29 18:16:05 -0700323 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 lru_cache_add_active(page);
325 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
326 page, vma->vm_page_prot))));
Nick Piggin9617d952006-01-06 00:11:12 -0800327 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700328 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
330 /* no need for flush_tlb */
331 return;
332out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 __free_page(page);
334 force_sig(SIGKILL, current);
335}
336
337#define EXTRA_STACK_VM_PAGES 20 /* random */
338
339int setup_arg_pages(struct linux_binprm *bprm,
340 unsigned long stack_top,
341 int executable_stack)
342{
343 unsigned long stack_base;
344 struct vm_area_struct *mpnt;
345 struct mm_struct *mm = current->mm;
346 int i, ret;
347 long arg_size;
348
349#ifdef CONFIG_STACK_GROWSUP
350 /* Move the argument and environment strings to the bottom of the
351 * stack space.
352 */
353 int offset, j;
354 char *to, *from;
355
356 /* Start by shifting all the pages down */
357 i = 0;
358 for (j = 0; j < MAX_ARG_PAGES; j++) {
359 struct page *page = bprm->page[j];
360 if (!page)
361 continue;
362 bprm->page[i++] = page;
363 }
364
365 /* Now move them within their pages */
366 offset = bprm->p % PAGE_SIZE;
367 to = kmap(bprm->page[0]);
368 for (j = 1; j < i; j++) {
369 memmove(to, to + offset, PAGE_SIZE - offset);
370 from = kmap(bprm->page[j]);
371 memcpy(to + PAGE_SIZE - offset, from, offset);
372 kunmap(bprm->page[j - 1]);
373 to = from;
374 }
375 memmove(to, to + offset, PAGE_SIZE - offset);
376 kunmap(bprm->page[j - 1]);
377
378 /* Limit stack size to 1GB */
379 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
380 if (stack_base > (1 << 30))
381 stack_base = 1 << 30;
382 stack_base = PAGE_ALIGN(stack_top - stack_base);
383
384 /* Adjust bprm->p to point to the end of the strings. */
385 bprm->p = stack_base + PAGE_SIZE * i - offset;
386
387 mm->arg_start = stack_base;
388 arg_size = i << PAGE_SHIFT;
389
390 /* zero pages that were copied above */
391 while (i < MAX_ARG_PAGES)
392 bprm->page[i++] = NULL;
393#else
394 stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
395 stack_base = PAGE_ALIGN(stack_base);
396 bprm->p += stack_base;
397 mm->arg_start = bprm->p;
398 arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
399#endif
400
401 arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
402
403 if (bprm->loader)
404 bprm->loader += stack_base;
405 bprm->exec += stack_base;
406
407 mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
408 if (!mpnt)
409 return -ENOMEM;
410
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 memset(mpnt, 0, sizeof(*mpnt));
412
413 down_write(&mm->mmap_sem);
414 {
415 mpnt->vm_mm = mm;
416#ifdef CONFIG_STACK_GROWSUP
417 mpnt->vm_start = stack_base;
418 mpnt->vm_end = stack_base + arg_size;
419#else
420 mpnt->vm_end = stack_top;
421 mpnt->vm_start = mpnt->vm_end - arg_size;
422#endif
423 /* Adjust stack execute permissions; explicitly enable
424 * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
425 * and leave alone (arch default) otherwise. */
426 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
427 mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
428 else if (executable_stack == EXSTACK_DISABLE_X)
429 mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
430 else
431 mpnt->vm_flags = VM_STACK_FLAGS;
432 mpnt->vm_flags |= mm->def_flags;
433 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
434 if ((ret = insert_vm_struct(mm, mpnt))) {
435 up_write(&mm->mmap_sem);
436 kmem_cache_free(vm_area_cachep, mpnt);
437 return ret;
438 }
439 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
440 }
441
442 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
443 struct page *page = bprm->page[i];
444 if (page) {
445 bprm->page[i] = NULL;
446 install_arg_page(mpnt, page, stack_base);
447 }
448 stack_base += PAGE_SIZE;
449 }
450 up_write(&mm->mmap_sem);
451
452 return 0;
453}
454
455EXPORT_SYMBOL(setup_arg_pages);
456
457#define free_arg_pages(bprm) do { } while (0)
458
459#else
460
461static inline void free_arg_pages(struct linux_binprm *bprm)
462{
463 int i;
464
465 for (i = 0; i < MAX_ARG_PAGES; i++) {
466 if (bprm->page[i])
467 __free_page(bprm->page[i]);
468 bprm->page[i] = NULL;
469 }
470}
471
472#endif /* CONFIG_MMU */
473
474struct file *open_exec(const char *name)
475{
476 struct nameidata nd;
477 int err;
478 struct file *file;
479
Oleg Drokinb5005312006-03-25 03:07:01 -0800480 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 file = ERR_PTR(err);
482
483 if (!err) {
484 struct inode *inode = nd.dentry->d_inode;
485 file = ERR_PTR(-EACCES);
486 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
487 S_ISREG(inode->i_mode)) {
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800488 int err = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 file = ERR_PTR(err);
490 if (!err) {
Trond Myklebust834f2a42005-10-18 14:20:16 -0700491 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 if (!IS_ERR(file)) {
493 err = deny_write_access(file);
494 if (err) {
495 fput(file);
496 file = ERR_PTR(err);
497 }
498 }
499out:
500 return file;
501 }
502 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700503 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 path_release(&nd);
505 }
506 goto out;
507}
508
509EXPORT_SYMBOL(open_exec);
510
511int kernel_read(struct file *file, unsigned long offset,
512 char *addr, unsigned long count)
513{
514 mm_segment_t old_fs;
515 loff_t pos = offset;
516 int result;
517
518 old_fs = get_fs();
519 set_fs(get_ds());
520 /* The cast to a user pointer is valid due to the set_fs() */
521 result = vfs_read(file, (void __user *)addr, count, &pos);
522 set_fs(old_fs);
523 return result;
524}
525
526EXPORT_SYMBOL(kernel_read);
527
528static int exec_mmap(struct mm_struct *mm)
529{
530 struct task_struct *tsk;
531 struct mm_struct * old_mm, *active_mm;
532
533 /* Notify parent that we're no longer interested in the old VM */
534 tsk = current;
535 old_mm = current->mm;
536 mm_release(tsk, old_mm);
537
538 if (old_mm) {
539 /*
540 * Make sure that if there is a core dump in progress
541 * for the old mm, we get out and die instead of going
542 * through with the exec. We must hold mmap_sem around
543 * checking core_waiters and changing tsk->mm. The
544 * core-inducing thread will increment core_waiters for
545 * each thread whose ->mm == old_mm.
546 */
547 down_read(&old_mm->mmap_sem);
548 if (unlikely(old_mm->core_waiters)) {
549 up_read(&old_mm->mmap_sem);
550 return -EINTR;
551 }
552 }
553 task_lock(tsk);
554 active_mm = tsk->active_mm;
555 tsk->mm = mm;
556 tsk->active_mm = mm;
557 activate_mm(active_mm, mm);
558 task_unlock(tsk);
559 arch_pick_mmap_layout(mm);
560 if (old_mm) {
561 up_read(&old_mm->mmap_sem);
Eric Sesterhenn7dddb122006-04-01 01:13:38 +0200562 BUG_ON(active_mm != old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 mmput(old_mm);
564 return 0;
565 }
566 mmdrop(active_mm);
567 return 0;
568}
569
570/*
571 * This function makes sure the current process has its own signal table,
572 * so that flush_signal_handlers can later reset the handlers without
573 * disturbing other processes. (Other processes might share the signal
574 * table via the CLONE_SIGHAND option to clone().)
575 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800576static int de_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577{
578 struct signal_struct *sig = tsk->signal;
579 struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
580 spinlock_t *lock = &oldsighand->siglock;
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300581 struct task_struct *leader = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 int count;
583
584 /*
585 * If we don't share sighandlers, then we aren't sharing anything
586 * and we can just re-use it all.
587 */
588 if (atomic_read(&oldsighand->count) <= 1) {
589 BUG_ON(atomic_read(&sig->count) != 1);
590 exit_itimers(sig);
591 return 0;
592 }
593
594 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
595 if (!newsighand)
596 return -ENOMEM;
597
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700598 if (thread_group_empty(tsk))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 goto no_thread_group;
600
601 /*
602 * Kill all other threads in the thread group.
603 * We must hold tasklist_lock to call zap_other_threads.
604 */
605 read_lock(&tasklist_lock);
606 spin_lock_irq(lock);
607 if (sig->flags & SIGNAL_GROUP_EXIT) {
608 /*
609 * Another group action in progress, just
610 * return so that the signal is processed.
611 */
612 spin_unlock_irq(lock);
613 read_unlock(&tasklist_lock);
614 kmem_cache_free(sighand_cachep, newsighand);
615 return -EAGAIN;
616 }
Oleg Nesterov14342612006-03-28 16:10:59 -0800617
618 /*
619 * child_reaper ignores SIGKILL, change it now.
620 * Reparenting needs write_lock on tasklist_lock,
621 * so it is safe to do it under read_lock.
622 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700623 if (unlikely(tsk->group_leader == child_reaper))
624 child_reaper = tsk;
Oleg Nesterov14342612006-03-28 16:10:59 -0800625
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700626 zap_other_threads(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 read_unlock(&tasklist_lock);
628
629 /*
630 * Account for the thread group leader hanging around:
631 */
Oleg Nesterov9e4e23b2005-10-30 15:01:37 -0800632 count = 1;
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700633 if (!thread_group_leader(tsk)) {
Oleg Nesterov9e4e23b2005-10-30 15:01:37 -0800634 count = 2;
Roland McGrath53231252005-07-12 13:58:27 -0700635 /*
636 * The SIGALRM timer survives the exec, but needs to point
637 * at us as the new group leader now. We have a race with
638 * a timer firing now getting the old leader, so we need to
639 * synchronize with any firing (by calling del_timer_sync)
640 * before we can safely let the old group leader die.
641 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700642 sig->tsk = tsk;
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800643 spin_unlock_irq(lock);
Thomas Gleixner2ff678b2006-01-09 20:52:34 -0800644 if (hrtimer_cancel(&sig->real_timer))
645 hrtimer_restart(&sig->real_timer);
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800646 spin_lock_irq(lock);
Roland McGrath53231252005-07-12 13:58:27 -0700647 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 while (atomic_read(&sig->count) > count) {
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700649 sig->group_exit_task = tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 sig->notify_count = count;
651 __set_current_state(TASK_UNINTERRUPTIBLE);
652 spin_unlock_irq(lock);
653 schedule();
654 spin_lock_irq(lock);
655 }
656 sig->group_exit_task = NULL;
657 sig->notify_count = 0;
658 spin_unlock_irq(lock);
659
660 /*
661 * At this point all other threads have exited, all we have to
662 * do is to wait for the thread group leader to become inactive,
663 * and to assume its PID:
664 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700665 if (!thread_group_leader(tsk)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 /*
667 * Wait for the thread group leader to be a zombie.
668 * It should already be zombie at this point, most
669 * of the time.
670 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700671 leader = tsk->group_leader;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 while (leader->exit_state != EXIT_ZOMBIE)
673 yield();
674
Roland McGrathf5e90282006-04-10 22:54:16 -0700675 /*
676 * The only record we have of the real-time age of a
677 * process, regardless of execs it's done, is start_time.
678 * All the past CPU time is accumulated in signal_struct
679 * from sister threads now dead. But in this non-leader
680 * exec, nothing survives from the original leader thread,
681 * whose birth marks the true age of this process now.
682 * When we take on its identity by switching to its PID, we
683 * also take its birthdate (always earlier than our own).
684 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700685 tsk->start_time = leader->start_time;
Roland McGrathf5e90282006-04-10 22:54:16 -0700686
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 write_lock_irq(&tasklist_lock);
688
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700689 BUG_ON(leader->tgid != tsk->tgid);
690 BUG_ON(tsk->pid == tsk->tgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 /*
692 * An exec() starts a new thread group with the
693 * TGID of the previous thread group. Rehash the
694 * two threads with a switched PID, and release
695 * the former thread group leader:
696 */
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800697
698 /* Become a process group leader with the old leader's pid.
Eric W. Biedermanc18258c2006-09-27 01:51:06 -0700699 * The old leader becomes a thread of the this thread group.
700 * Note: The old leader also uses this pid until release_task
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800701 * is called. Odd but simple and correct.
702 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700703 detach_pid(tsk, PIDTYPE_PID);
704 tsk->pid = leader->pid;
705 attach_pid(tsk, PIDTYPE_PID, tsk->pid);
706 transfer_pid(leader, tsk, PIDTYPE_PGID);
707 transfer_pid(leader, tsk, PIDTYPE_SID);
708 list_replace_rcu(&leader->tasks, &tsk->tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700710 tsk->group_leader = tsk;
711 leader->group_leader = tsk;
Eric W. Biedermande12a782006-04-10 17:16:49 -0600712
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700713 tsk->exit_signal = SIGCHLD;
Oleg Nesterov962b5642005-11-23 13:37:43 -0800714
715 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
716 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
718 write_unlock_irq(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 }
720
721 /*
Alexander Nybergfb085cf2005-09-14 18:54:06 +0200722 * There may be one thread left which is just exiting,
723 * but it's safe to stop telling the group to kill themselves.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 */
725 sig->flags = 0;
726
727no_thread_group:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 exit_itimers(sig);
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300729 if (leader)
730 release_task(leader);
731
732 BUG_ON(atomic_read(&sig->count) != 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733
734 if (atomic_read(&oldsighand->count) == 1) {
735 /*
736 * Now that we nuked the rest of the thread group,
737 * it turns out we are not sharing sighand any more either.
738 * So we can just keep it.
739 */
740 kmem_cache_free(sighand_cachep, newsighand);
741 } else {
742 /*
743 * Move our state over to newsighand and switch it in.
744 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 atomic_set(&newsighand->count, 1);
746 memcpy(newsighand->action, oldsighand->action,
747 sizeof(newsighand->action));
748
749 write_lock_irq(&tasklist_lock);
750 spin_lock(&oldsighand->siglock);
Dave Jones513627d2006-08-27 01:23:57 -0700751 spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700753 rcu_assign_pointer(tsk->sighand, newsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 recalc_sigpending();
755
756 spin_unlock(&newsighand->siglock);
757 spin_unlock(&oldsighand->siglock);
758 write_unlock_irq(&tasklist_lock);
759
760 if (atomic_dec_and_test(&oldsighand->count))
Oleg Nesterovaa1757f2006-03-28 16:11:12 -0800761 kmem_cache_free(sighand_cachep, oldsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 }
763
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700764 BUG_ON(!thread_group_leader(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 return 0;
766}
767
768/*
769 * These functions flushes out all traces of the currently running executable
770 * so that a new one can be started
771 */
772
Arjan van de Ven858119e2006-01-14 13:20:43 -0800773static void flush_old_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774{
775 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700776 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 spin_lock(&files->file_lock);
779 for (;;) {
780 unsigned long set, i;
781
782 j++;
783 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700784 fdt = files_fdtable(files);
785 if (i >= fdt->max_fds || i >= fdt->max_fdset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700787 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 if (!set)
789 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700790 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 spin_unlock(&files->file_lock);
792 for ( ; set ; i++,set >>= 1) {
793 if (set & 1) {
794 sys_close(i);
795 }
796 }
797 spin_lock(&files->file_lock);
798
799 }
800 spin_unlock(&files->file_lock);
801}
802
803void get_task_comm(char *buf, struct task_struct *tsk)
804{
805 /* buf must be at least sizeof(tsk->comm) in size */
806 task_lock(tsk);
807 strncpy(buf, tsk->comm, sizeof(tsk->comm));
808 task_unlock(tsk);
809}
810
811void set_task_comm(struct task_struct *tsk, char *buf)
812{
813 task_lock(tsk);
814 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
815 task_unlock(tsk);
816}
817
818int flush_old_exec(struct linux_binprm * bprm)
819{
820 char * name;
821 int i, ch, retval;
822 struct files_struct *files;
823 char tcomm[sizeof(current->comm)];
824
825 /*
826 * Make sure we have a private signal table and that
827 * we are unassociated from the previous thread group.
828 */
829 retval = de_thread(current);
830 if (retval)
831 goto out;
832
833 /*
834 * Make sure we have private file handles. Ask the
835 * fork helper to do the work for us and the exit
836 * helper to do the cleanup of the old one.
837 */
838 files = current->files; /* refcounted so safe to hold */
839 retval = unshare_files();
840 if (retval)
841 goto out;
842 /*
843 * Release all of the old mmap stuff
844 */
845 retval = exec_mmap(bprm->mm);
846 if (retval)
847 goto mmap_failed;
848
849 bprm->mm = NULL; /* We're using it now */
850
851 /* This is the point of no return */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 put_files_struct(files);
853
854 current->sas_ss_sp = current->sas_ss_size = 0;
855
856 if (current->euid == current->uid && current->egid == current->gid)
857 current->mm->dumpable = 1;
Alan Coxd6e71142005-06-23 00:09:43 -0700858 else
859 current->mm->dumpable = suid_dumpable;
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700862
863 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 for (i=0; (ch = *(name++)) != '\0';) {
865 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700866 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 else
868 if (i < (sizeof(tcomm) - 1))
869 tcomm[i++] = ch;
870 }
871 tcomm[i] = '\0';
872 set_task_comm(current, tcomm);
873
874 current->flags &= ~PF_RANDOMIZE;
875 flush_thread();
876
Benjamin Herrenschmidt0551fbd2006-02-28 16:59:19 -0800877 /* Set the new mm task size. We have to do that late because it may
878 * depend on TIF_32BIT which is only updated in flush_thread() on
879 * some architectures like powerpc
880 */
881 current->mm->task_size = TASK_SIZE;
882
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800884 file_permission(bprm->file, MAY_READ) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
886 suid_keys(current);
Alan Coxd6e71142005-06-23 00:09:43 -0700887 current->mm->dumpable = suid_dumpable;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 }
889
890 /* An exec changes our domain. We are no longer part of the thread
891 group */
892
893 current->self_exec_id++;
894
895 flush_signal_handlers(current, 0);
896 flush_old_files(current->files);
897
898 return 0;
899
900mmap_failed:
Kirill Korotaev3b9b8ab2006-09-29 02:00:05 -0700901 reset_files_struct(current, files);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902out:
903 return retval;
904}
905
906EXPORT_SYMBOL(flush_old_exec);
907
908/*
909 * Fill the binprm structure from the inode.
910 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
911 */
912int prepare_binprm(struct linux_binprm *bprm)
913{
914 int mode;
915 struct inode * inode = bprm->file->f_dentry->d_inode;
916 int retval;
917
918 mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (bprm->file->f_op == NULL)
920 return -EACCES;
921
922 bprm->e_uid = current->euid;
923 bprm->e_gid = current->egid;
924
925 if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
926 /* Set-uid? */
927 if (mode & S_ISUID) {
928 current->personality &= ~PER_CLEAR_ON_SETID;
929 bprm->e_uid = inode->i_uid;
930 }
931
932 /* Set-gid? */
933 /*
934 * If setgid is set but no group execute bit then this
935 * is a candidate for mandatory locking, not a setgid
936 * executable.
937 */
938 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
939 current->personality &= ~PER_CLEAR_ON_SETID;
940 bprm->e_gid = inode->i_gid;
941 }
942 }
943
944 /* fill in binprm security blob */
945 retval = security_bprm_set(bprm);
946 if (retval)
947 return retval;
948
949 memset(bprm->buf,0,BINPRM_BUF_SIZE);
950 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
951}
952
953EXPORT_SYMBOL(prepare_binprm);
954
Arjan van de Ven858119e2006-01-14 13:20:43 -0800955static int unsafe_exec(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956{
957 int unsafe = 0;
958 if (p->ptrace & PT_PTRACED) {
959 if (p->ptrace & PT_PTRACE_CAP)
960 unsafe |= LSM_UNSAFE_PTRACE_CAP;
961 else
962 unsafe |= LSM_UNSAFE_PTRACE;
963 }
964 if (atomic_read(&p->fs->count) > 1 ||
965 atomic_read(&p->files->count) > 1 ||
966 atomic_read(&p->sighand->count) > 1)
967 unsafe |= LSM_UNSAFE_SHARE;
968
969 return unsafe;
970}
971
972void compute_creds(struct linux_binprm *bprm)
973{
974 int unsafe;
975
976 if (bprm->e_uid != current->uid)
977 suid_keys(current);
978 exec_keys(current);
979
980 task_lock(current);
981 unsafe = unsafe_exec(current);
982 security_bprm_apply_creds(bprm, unsafe);
983 task_unlock(current);
984 security_bprm_post_apply_creds(bprm);
985}
986
987EXPORT_SYMBOL(compute_creds);
988
989void remove_arg_zero(struct linux_binprm *bprm)
990{
991 if (bprm->argc) {
992 unsigned long offset;
993 char * kaddr;
994 struct page *page;
995
996 offset = bprm->p % PAGE_SIZE;
997 goto inside;
998
999 while (bprm->p++, *(kaddr+offset++)) {
1000 if (offset != PAGE_SIZE)
1001 continue;
1002 offset = 0;
1003 kunmap_atomic(kaddr, KM_USER0);
1004inside:
1005 page = bprm->page[bprm->p/PAGE_SIZE];
1006 kaddr = kmap_atomic(page, KM_USER0);
1007 }
1008 kunmap_atomic(kaddr, KM_USER0);
1009 bprm->argc--;
1010 }
1011}
1012
1013EXPORT_SYMBOL(remove_arg_zero);
1014
1015/*
1016 * cycle the list of binary formats handler, until one recognizes the image
1017 */
1018int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1019{
1020 int try,retval;
1021 struct linux_binfmt *fmt;
1022#ifdef __alpha__
1023 /* handle /sbin/loader.. */
1024 {
1025 struct exec * eh = (struct exec *) bprm->buf;
1026
1027 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1028 (eh->fh.f_flags & 0x3000) == 0x3000)
1029 {
1030 struct file * file;
1031 unsigned long loader;
1032
1033 allow_write_access(bprm->file);
1034 fput(bprm->file);
1035 bprm->file = NULL;
1036
1037 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1038
1039 file = open_exec("/sbin/loader");
1040 retval = PTR_ERR(file);
1041 if (IS_ERR(file))
1042 return retval;
1043
1044 /* Remember if the application is TASO. */
1045 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1046
1047 bprm->file = file;
1048 bprm->loader = loader;
1049 retval = prepare_binprm(bprm);
1050 if (retval<0)
1051 return retval;
1052 /* should call search_binary_handler recursively here,
1053 but it does not matter */
1054 }
1055 }
1056#endif
1057 retval = security_bprm_check(bprm);
1058 if (retval)
1059 return retval;
1060
1061 /* kernel module loader fixup */
1062 /* so we don't try to load run modprobe in kernel space. */
1063 set_fs(USER_DS);
Al Viro473ae302006-04-26 14:04:08 -04001064
1065 retval = audit_bprm(bprm);
1066 if (retval)
1067 return retval;
1068
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 retval = -ENOENT;
1070 for (try=0; try<2; try++) {
1071 read_lock(&binfmt_lock);
1072 for (fmt = formats ; fmt ; fmt = fmt->next) {
1073 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1074 if (!fn)
1075 continue;
1076 if (!try_module_get(fmt->module))
1077 continue;
1078 read_unlock(&binfmt_lock);
1079 retval = fn(bprm, regs);
1080 if (retval >= 0) {
1081 put_binfmt(fmt);
1082 allow_write_access(bprm->file);
1083 if (bprm->file)
1084 fput(bprm->file);
1085 bprm->file = NULL;
1086 current->did_exec = 1;
Matt Helsley9f460802005-11-07 00:59:16 -08001087 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 return retval;
1089 }
1090 read_lock(&binfmt_lock);
1091 put_binfmt(fmt);
1092 if (retval != -ENOEXEC || bprm->mm == NULL)
1093 break;
1094 if (!bprm->file) {
1095 read_unlock(&binfmt_lock);
1096 return retval;
1097 }
1098 }
1099 read_unlock(&binfmt_lock);
1100 if (retval != -ENOEXEC || bprm->mm == NULL) {
1101 break;
1102#ifdef CONFIG_KMOD
1103 }else{
1104#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1105 if (printable(bprm->buf[0]) &&
1106 printable(bprm->buf[1]) &&
1107 printable(bprm->buf[2]) &&
1108 printable(bprm->buf[3]))
1109 break; /* -ENOEXEC */
1110 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1111#endif
1112 }
1113 }
1114 return retval;
1115}
1116
1117EXPORT_SYMBOL(search_binary_handler);
1118
1119/*
1120 * sys_execve() executes a new program.
1121 */
1122int do_execve(char * filename,
1123 char __user *__user *argv,
1124 char __user *__user *envp,
1125 struct pt_regs * regs)
1126{
1127 struct linux_binprm *bprm;
1128 struct file *file;
1129 int retval;
1130 int i;
1131
1132 retval = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001133 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 if (!bprm)
1135 goto out_ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136
1137 file = open_exec(filename);
1138 retval = PTR_ERR(file);
1139 if (IS_ERR(file))
1140 goto out_kfree;
1141
1142 sched_exec();
1143
1144 bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1145
1146 bprm->file = file;
1147 bprm->filename = filename;
1148 bprm->interp = filename;
1149 bprm->mm = mm_alloc();
1150 retval = -ENOMEM;
1151 if (!bprm->mm)
1152 goto out_file;
1153
1154 retval = init_new_context(current, bprm->mm);
1155 if (retval < 0)
1156 goto out_mm;
1157
1158 bprm->argc = count(argv, bprm->p / sizeof(void *));
1159 if ((retval = bprm->argc) < 0)
1160 goto out_mm;
1161
1162 bprm->envc = count(envp, bprm->p / sizeof(void *));
1163 if ((retval = bprm->envc) < 0)
1164 goto out_mm;
1165
1166 retval = security_bprm_alloc(bprm);
1167 if (retval)
1168 goto out;
1169
1170 retval = prepare_binprm(bprm);
1171 if (retval < 0)
1172 goto out;
1173
1174 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1175 if (retval < 0)
1176 goto out;
1177
1178 bprm->exec = bprm->p;
1179 retval = copy_strings(bprm->envc, envp, bprm);
1180 if (retval < 0)
1181 goto out;
1182
1183 retval = copy_strings(bprm->argc, argv, bprm);
1184 if (retval < 0)
1185 goto out;
1186
1187 retval = search_binary_handler(bprm,regs);
1188 if (retval >= 0) {
1189 free_arg_pages(bprm);
1190
1191 /* execve success */
1192 security_bprm_free(bprm);
1193 acct_update_integrals(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 kfree(bprm);
1195 return retval;
1196 }
1197
1198out:
1199 /* Something went wrong, return the inode and free the argument pages*/
1200 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1201 struct page * page = bprm->page[i];
1202 if (page)
1203 __free_page(page);
1204 }
1205
1206 if (bprm->security)
1207 security_bprm_free(bprm);
1208
1209out_mm:
1210 if (bprm->mm)
1211 mmdrop(bprm->mm);
1212
1213out_file:
1214 if (bprm->file) {
1215 allow_write_access(bprm->file);
1216 fput(bprm->file);
1217 }
1218
1219out_kfree:
1220 kfree(bprm);
1221
1222out_ret:
1223 return retval;
1224}
1225
1226int set_binfmt(struct linux_binfmt *new)
1227{
1228 struct linux_binfmt *old = current->binfmt;
1229
1230 if (new) {
1231 if (!try_module_get(new->module))
1232 return -1;
1233 }
1234 current->binfmt = new;
1235 if (old)
1236 module_put(old->module);
1237 return 0;
1238}
1239
1240EXPORT_SYMBOL(set_binfmt);
1241
1242#define CORENAME_MAX_SIZE 64
1243
1244/* format_corename will inspect the pattern parameter, and output a
1245 * name into corename, which must have space for at least
1246 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1247 */
1248static void format_corename(char *corename, const char *pattern, long signr)
1249{
1250 const char *pat_ptr = pattern;
1251 char *out_ptr = corename;
1252 char *const out_end = corename + CORENAME_MAX_SIZE;
1253 int rc;
1254 int pid_in_pattern = 0;
1255
1256 /* Repeat as long as we have more pattern to process and more output
1257 space */
1258 while (*pat_ptr) {
1259 if (*pat_ptr != '%') {
1260 if (out_ptr == out_end)
1261 goto out;
1262 *out_ptr++ = *pat_ptr++;
1263 } else {
1264 switch (*++pat_ptr) {
1265 case 0:
1266 goto out;
1267 /* Double percent, output one percent */
1268 case '%':
1269 if (out_ptr == out_end)
1270 goto out;
1271 *out_ptr++ = '%';
1272 break;
1273 /* pid */
1274 case 'p':
1275 pid_in_pattern = 1;
1276 rc = snprintf(out_ptr, out_end - out_ptr,
1277 "%d", current->tgid);
1278 if (rc > out_end - out_ptr)
1279 goto out;
1280 out_ptr += rc;
1281 break;
1282 /* uid */
1283 case 'u':
1284 rc = snprintf(out_ptr, out_end - out_ptr,
1285 "%d", current->uid);
1286 if (rc > out_end - out_ptr)
1287 goto out;
1288 out_ptr += rc;
1289 break;
1290 /* gid */
1291 case 'g':
1292 rc = snprintf(out_ptr, out_end - out_ptr,
1293 "%d", current->gid);
1294 if (rc > out_end - out_ptr)
1295 goto out;
1296 out_ptr += rc;
1297 break;
1298 /* signal that caused the coredump */
1299 case 's':
1300 rc = snprintf(out_ptr, out_end - out_ptr,
1301 "%ld", signr);
1302 if (rc > out_end - out_ptr)
1303 goto out;
1304 out_ptr += rc;
1305 break;
1306 /* UNIX time of coredump */
1307 case 't': {
1308 struct timeval tv;
1309 do_gettimeofday(&tv);
1310 rc = snprintf(out_ptr, out_end - out_ptr,
1311 "%lu", tv.tv_sec);
1312 if (rc > out_end - out_ptr)
1313 goto out;
1314 out_ptr += rc;
1315 break;
1316 }
1317 /* hostname */
1318 case 'h':
1319 down_read(&uts_sem);
1320 rc = snprintf(out_ptr, out_end - out_ptr,
1321 "%s", system_utsname.nodename);
1322 up_read(&uts_sem);
1323 if (rc > out_end - out_ptr)
1324 goto out;
1325 out_ptr += rc;
1326 break;
1327 /* executable */
1328 case 'e':
1329 rc = snprintf(out_ptr, out_end - out_ptr,
1330 "%s", current->comm);
1331 if (rc > out_end - out_ptr)
1332 goto out;
1333 out_ptr += rc;
1334 break;
1335 default:
1336 break;
1337 }
1338 ++pat_ptr;
1339 }
1340 }
1341 /* Backward compatibility with core_uses_pid:
1342 *
1343 * If core_pattern does not include a %p (as is the default)
1344 * and core_uses_pid is set, then .%pid will be appended to
1345 * the filename */
1346 if (!pid_in_pattern
1347 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1348 rc = snprintf(out_ptr, out_end - out_ptr,
1349 ".%d", current->tgid);
1350 if (rc > out_end - out_ptr)
1351 goto out;
1352 out_ptr += rc;
1353 }
1354 out:
1355 *out_ptr = 0;
1356}
1357
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001358static void zap_process(struct task_struct *start)
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001359{
1360 struct task_struct *t;
Oleg Nesterov281de332006-06-26 00:26:06 -07001361
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001362 start->signal->flags = SIGNAL_GROUP_EXIT;
1363 start->signal->group_stop_count = 0;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001364
1365 t = start;
1366 do {
1367 if (t != current && t->mm) {
1368 t->mm->core_waiters++;
Oleg Nesterov281de332006-06-26 00:26:06 -07001369 sigaddset(&t->pending.signal, SIGKILL);
1370 signal_wake_up(t, 1);
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001371 }
1372 } while ((t = next_thread(t)) != start);
1373}
1374
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001375static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1376 int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377{
1378 struct task_struct *g, *p;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001379 unsigned long flags;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001380 int err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001382 spin_lock_irq(&tsk->sighand->siglock);
1383 if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001384 tsk->signal->group_exit_code = exit_code;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001385 zap_process(tsk);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001386 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 }
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001388 spin_unlock_irq(&tsk->sighand->siglock);
1389 if (err)
1390 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001392 if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1393 goto done;
1394
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001395 rcu_read_lock();
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001396 for_each_process(g) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001397 if (g == tsk->group_leader)
1398 continue;
1399
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001400 p = g;
1401 do {
1402 if (p->mm) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001403 if (p->mm == mm) {
1404 /*
1405 * p->sighand can't disappear, but
1406 * may be changed by de_thread()
1407 */
1408 lock_task_sighand(p, &flags);
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001409 zap_process(p);
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001410 unlock_task_sighand(p, &flags);
1411 }
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001412 break;
1413 }
1414 } while ((p = next_thread(p)) != g);
1415 }
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001416 rcu_read_unlock();
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001417done:
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001418 return mm->core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419}
1420
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001421static int coredump_wait(int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422{
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001423 struct task_struct *tsk = current;
1424 struct mm_struct *mm = tsk->mm;
1425 struct completion startup_done;
1426 struct completion *vfork_done;
Oleg Nesterov2384f552005-10-30 15:02:47 -08001427 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001429 init_completion(&mm->core_done);
1430 init_completion(&startup_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 mm->core_startup_done = &startup_done;
1432
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001433 core_waiters = zap_threads(tsk, mm, exit_code);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001434 up_write(&mm->mmap_sem);
1435
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001436 if (unlikely(core_waiters < 0))
1437 goto fail;
1438
1439 /*
1440 * Make sure nobody is waiting for us to release the VM,
1441 * otherwise we can deadlock when we wait on each other
1442 */
1443 vfork_done = tsk->vfork_done;
1444 if (vfork_done) {
1445 tsk->vfork_done = NULL;
1446 complete(vfork_done);
1447 }
1448
Oleg Nesterov2384f552005-10-30 15:02:47 -08001449 if (core_waiters)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 wait_for_completion(&startup_done);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001451fail:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 BUG_ON(mm->core_waiters);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001453 return core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454}
1455
1456int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1457{
1458 char corename[CORENAME_MAX_SIZE + 1];
1459 struct mm_struct *mm = current->mm;
1460 struct linux_binfmt * binfmt;
1461 struct inode * inode;
1462 struct file * file;
1463 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001464 int fsuid = current->fsuid;
1465 int flag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466
1467 binfmt = current->binfmt;
1468 if (!binfmt || !binfmt->core_dump)
1469 goto fail;
1470 down_write(&mm->mmap_sem);
1471 if (!mm->dumpable) {
1472 up_write(&mm->mmap_sem);
1473 goto fail;
1474 }
Alan Coxd6e71142005-06-23 00:09:43 -07001475
1476 /*
1477 * We cannot trust fsuid as being the "true" uid of the
1478 * process nor do we know its entire history. We only know it
1479 * was tainted so we dump it as root in mode 2.
1480 */
1481 if (mm->dumpable == 2) { /* Setuid core dump mode */
1482 flag = O_EXCL; /* Stop rewrite attacks */
1483 current->fsuid = 0; /* Dump root private */
1484 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 mm->dumpable = 0;
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001486
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001487 retval = coredump_wait(exit_code);
1488 if (retval < 0)
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001489 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490
1491 /*
1492 * Clear any false indication of pending signals that might
1493 * be seen by the filesystem code called to write the core file.
1494 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 clear_thread_flag(TIF_SIGPENDING);
1496
1497 if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1498 goto fail_unlock;
1499
1500 /*
1501 * lock_kernel() because format_corename() is controlled by sysctl, which
1502 * uses lock_kernel()
1503 */
1504 lock_kernel();
1505 format_corename(corename, core_pattern, signr);
1506 unlock_kernel();
Alan Coxd6e71142005-06-23 00:09:43 -07001507 file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 if (IS_ERR(file))
1509 goto fail_unlock;
1510 inode = file->f_dentry->d_inode;
1511 if (inode->i_nlink > 1)
1512 goto close_fail; /* multiple links - don't dump */
1513 if (d_unhashed(file->f_dentry))
1514 goto close_fail;
1515
1516 if (!S_ISREG(inode->i_mode))
1517 goto close_fail;
1518 if (!file->f_op)
1519 goto close_fail;
1520 if (!file->f_op->write)
1521 goto close_fail;
NeilBrown4a301312006-01-08 01:02:39 -08001522 if (do_truncate(file->f_dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 goto close_fail;
1524
1525 retval = binfmt->core_dump(signr, regs, file);
1526
1527 if (retval)
1528 current->signal->group_exit_code |= 0x80;
1529close_fail:
1530 filp_close(file, NULL);
1531fail_unlock:
Alan Coxd6e71142005-06-23 00:09:43 -07001532 current->fsuid = fsuid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 complete_all(&mm->core_done);
1534fail:
1535 return retval;
1536}