blob: 10d493fea7ce6a9e4de05ff01facdf162bb9dd8b [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>
51
52#include <asm/uaccess.h>
53#include <asm/mmu_context.h>
54
55#ifdef CONFIG_KMOD
56#include <linux/kmod.h>
57#endif
58
59int core_uses_pid;
60char core_pattern[65] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070061int suid_dumpable = 0;
62
63EXPORT_SYMBOL(suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064/* The maximal length of core_pattern is also specified in sysctl.c */
65
66static struct linux_binfmt *formats;
67static DEFINE_RWLOCK(binfmt_lock);
68
69int register_binfmt(struct linux_binfmt * fmt)
70{
71 struct linux_binfmt ** tmp = &formats;
72
73 if (!fmt)
74 return -EINVAL;
75 if (fmt->next)
76 return -EBUSY;
77 write_lock(&binfmt_lock);
78 while (*tmp) {
79 if (fmt == *tmp) {
80 write_unlock(&binfmt_lock);
81 return -EBUSY;
82 }
83 tmp = &(*tmp)->next;
84 }
85 fmt->next = formats;
86 formats = fmt;
87 write_unlock(&binfmt_lock);
88 return 0;
89}
90
91EXPORT_SYMBOL(register_binfmt);
92
93int unregister_binfmt(struct linux_binfmt * fmt)
94{
95 struct linux_binfmt ** tmp = &formats;
96
97 write_lock(&binfmt_lock);
98 while (*tmp) {
99 if (fmt == *tmp) {
100 *tmp = fmt->next;
101 write_unlock(&binfmt_lock);
102 return 0;
103 }
104 tmp = &(*tmp)->next;
105 }
106 write_unlock(&binfmt_lock);
107 return -EINVAL;
108}
109
110EXPORT_SYMBOL(unregister_binfmt);
111
112static inline void put_binfmt(struct linux_binfmt * fmt)
113{
114 module_put(fmt->module);
115}
116
117/*
118 * Note that a shared library must be both readable and executable due to
119 * security reasons.
120 *
121 * Also note that we take the address to load from from the file itself.
122 */
123asmlinkage long sys_uselib(const char __user * library)
124{
125 struct file * file;
126 struct nameidata nd;
127 int error;
128
Trond Myklebust834f2a42005-10-18 14:20:16 -0700129 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 if (error)
131 goto out;
132
133 error = -EINVAL;
134 if (!S_ISREG(nd.dentry->d_inode->i_mode))
135 goto exit;
136
137 error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd);
138 if (error)
139 goto exit;
140
Trond Myklebust834f2a42005-10-18 14:20:16 -0700141 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 error = PTR_ERR(file);
143 if (IS_ERR(file))
144 goto out;
145
146 error = -ENOEXEC;
147 if(file->f_op) {
148 struct linux_binfmt * fmt;
149
150 read_lock(&binfmt_lock);
151 for (fmt = formats ; fmt ; fmt = fmt->next) {
152 if (!fmt->load_shlib)
153 continue;
154 if (!try_module_get(fmt->module))
155 continue;
156 read_unlock(&binfmt_lock);
157 error = fmt->load_shlib(file);
158 read_lock(&binfmt_lock);
159 put_binfmt(fmt);
160 if (error != -ENOEXEC)
161 break;
162 }
163 read_unlock(&binfmt_lock);
164 }
165 fput(file);
166out:
167 return error;
168exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700169 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 path_release(&nd);
171 goto out;
172}
173
174/*
175 * count() counts the number of strings in array ARGV.
176 */
177static int count(char __user * __user * argv, int max)
178{
179 int i = 0;
180
181 if (argv != NULL) {
182 for (;;) {
183 char __user * p;
184
185 if (get_user(p, argv))
186 return -EFAULT;
187 if (!p)
188 break;
189 argv++;
190 if(++i > max)
191 return -E2BIG;
192 cond_resched();
193 }
194 }
195 return i;
196}
197
198/*
199 * 'copy_strings()' copies argument/environment strings from user
200 * memory to free pages in kernel mem. These are in a format ready
201 * to be put directly into the top of new user memory.
202 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700203static int copy_strings(int argc, char __user * __user * argv,
204 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205{
206 struct page *kmapped_page = NULL;
207 char *kaddr = NULL;
208 int ret;
209
210 while (argc-- > 0) {
211 char __user *str;
212 int len;
213 unsigned long pos;
214
215 if (get_user(str, argv+argc) ||
216 !(len = strnlen_user(str, bprm->p))) {
217 ret = -EFAULT;
218 goto out;
219 }
220
221 if (bprm->p < len) {
222 ret = -E2BIG;
223 goto out;
224 }
225
226 bprm->p -= len;
227 /* XXX: add architecture specific overflow check here. */
228 pos = bprm->p;
229
230 while (len > 0) {
231 int i, new, err;
232 int offset, bytes_to_copy;
233 struct page *page;
234
235 offset = pos % PAGE_SIZE;
236 i = pos/PAGE_SIZE;
237 page = bprm->page[i];
238 new = 0;
239 if (!page) {
240 page = alloc_page(GFP_HIGHUSER);
241 bprm->page[i] = page;
242 if (!page) {
243 ret = -ENOMEM;
244 goto out;
245 }
246 new = 1;
247 }
248
249 if (page != kmapped_page) {
250 if (kmapped_page)
251 kunmap(kmapped_page);
252 kmapped_page = page;
253 kaddr = kmap(kmapped_page);
254 }
255 if (new && offset)
256 memset(kaddr, 0, offset);
257 bytes_to_copy = PAGE_SIZE - offset;
258 if (bytes_to_copy > len) {
259 bytes_to_copy = len;
260 if (new)
261 memset(kaddr+offset+len, 0,
262 PAGE_SIZE-offset-len);
263 }
264 err = copy_from_user(kaddr+offset, str, bytes_to_copy);
265 if (err) {
266 ret = -EFAULT;
267 goto out;
268 }
269
270 pos += bytes_to_copy;
271 str += bytes_to_copy;
272 len -= bytes_to_copy;
273 }
274 }
275 ret = 0;
276out:
277 if (kmapped_page)
278 kunmap(kmapped_page);
279 return ret;
280}
281
282/*
283 * Like copy_strings, but get argv and its values from kernel memory.
284 */
285int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
286{
287 int r;
288 mm_segment_t oldfs = get_fs();
289 set_fs(KERNEL_DS);
290 r = copy_strings(argc, (char __user * __user *)argv, bprm);
291 set_fs(oldfs);
292 return r;
293}
294
295EXPORT_SYMBOL(copy_strings_kernel);
296
297#ifdef CONFIG_MMU
298/*
299 * This routine is used to map in a page into an address space: needed by
300 * execve() for the initial stack and environment pages.
301 *
302 * vma->vm_mm->mmap_sem is held for writing.
303 */
304void install_arg_page(struct vm_area_struct *vma,
305 struct page *page, unsigned long address)
306{
307 struct mm_struct *mm = vma->vm_mm;
308 pgd_t * pgd;
309 pud_t * pud;
310 pmd_t * pmd;
311 pte_t * pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700312 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
314 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickinsc74df322005-10-29 18:16:23 -0700315 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
317 flush_dcache_page(page);
318 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 pud = pud_alloc(mm, pgd, address);
320 if (!pud)
321 goto out;
322 pmd = pmd_alloc(mm, pud, address);
323 if (!pmd)
324 goto out;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700325 pte = pte_alloc_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 if (!pte)
327 goto out;
328 if (!pte_none(*pte)) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700329 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 goto out;
331 }
Hugh Dickins42946212005-10-29 18:16:05 -0700332 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 lru_cache_add_active(page);
334 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
335 page, vma->vm_page_prot))));
336 page_add_anon_rmap(page, vma, address);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700337 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 /* no need for flush_tlb */
340 return;
341out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 __free_page(page);
343 force_sig(SIGKILL, current);
344}
345
346#define EXTRA_STACK_VM_PAGES 20 /* random */
347
348int setup_arg_pages(struct linux_binprm *bprm,
349 unsigned long stack_top,
350 int executable_stack)
351{
352 unsigned long stack_base;
353 struct vm_area_struct *mpnt;
354 struct mm_struct *mm = current->mm;
355 int i, ret;
356 long arg_size;
357
358#ifdef CONFIG_STACK_GROWSUP
359 /* Move the argument and environment strings to the bottom of the
360 * stack space.
361 */
362 int offset, j;
363 char *to, *from;
364
365 /* Start by shifting all the pages down */
366 i = 0;
367 for (j = 0; j < MAX_ARG_PAGES; j++) {
368 struct page *page = bprm->page[j];
369 if (!page)
370 continue;
371 bprm->page[i++] = page;
372 }
373
374 /* Now move them within their pages */
375 offset = bprm->p % PAGE_SIZE;
376 to = kmap(bprm->page[0]);
377 for (j = 1; j < i; j++) {
378 memmove(to, to + offset, PAGE_SIZE - offset);
379 from = kmap(bprm->page[j]);
380 memcpy(to + PAGE_SIZE - offset, from, offset);
381 kunmap(bprm->page[j - 1]);
382 to = from;
383 }
384 memmove(to, to + offset, PAGE_SIZE - offset);
385 kunmap(bprm->page[j - 1]);
386
387 /* Limit stack size to 1GB */
388 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
389 if (stack_base > (1 << 30))
390 stack_base = 1 << 30;
391 stack_base = PAGE_ALIGN(stack_top - stack_base);
392
393 /* Adjust bprm->p to point to the end of the strings. */
394 bprm->p = stack_base + PAGE_SIZE * i - offset;
395
396 mm->arg_start = stack_base;
397 arg_size = i << PAGE_SHIFT;
398
399 /* zero pages that were copied above */
400 while (i < MAX_ARG_PAGES)
401 bprm->page[i++] = NULL;
402#else
403 stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
404 stack_base = PAGE_ALIGN(stack_base);
405 bprm->p += stack_base;
406 mm->arg_start = bprm->p;
407 arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
408#endif
409
410 arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
411
412 if (bprm->loader)
413 bprm->loader += stack_base;
414 bprm->exec += stack_base;
415
416 mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
417 if (!mpnt)
418 return -ENOMEM;
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 memset(mpnt, 0, sizeof(*mpnt));
421
422 down_write(&mm->mmap_sem);
423 {
424 mpnt->vm_mm = mm;
425#ifdef CONFIG_STACK_GROWSUP
426 mpnt->vm_start = stack_base;
427 mpnt->vm_end = stack_base + arg_size;
428#else
429 mpnt->vm_end = stack_top;
430 mpnt->vm_start = mpnt->vm_end - arg_size;
431#endif
432 /* Adjust stack execute permissions; explicitly enable
433 * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
434 * and leave alone (arch default) otherwise. */
435 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
436 mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
437 else if (executable_stack == EXSTACK_DISABLE_X)
438 mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
439 else
440 mpnt->vm_flags = VM_STACK_FLAGS;
441 mpnt->vm_flags |= mm->def_flags;
442 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
443 if ((ret = insert_vm_struct(mm, mpnt))) {
444 up_write(&mm->mmap_sem);
445 kmem_cache_free(vm_area_cachep, mpnt);
446 return ret;
447 }
448 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
449 }
450
451 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
452 struct page *page = bprm->page[i];
453 if (page) {
454 bprm->page[i] = NULL;
455 install_arg_page(mpnt, page, stack_base);
456 }
457 stack_base += PAGE_SIZE;
458 }
459 up_write(&mm->mmap_sem);
460
461 return 0;
462}
463
464EXPORT_SYMBOL(setup_arg_pages);
465
466#define free_arg_pages(bprm) do { } while (0)
467
468#else
469
470static inline void free_arg_pages(struct linux_binprm *bprm)
471{
472 int i;
473
474 for (i = 0; i < MAX_ARG_PAGES; i++) {
475 if (bprm->page[i])
476 __free_page(bprm->page[i]);
477 bprm->page[i] = NULL;
478 }
479}
480
481#endif /* CONFIG_MMU */
482
483struct file *open_exec(const char *name)
484{
485 struct nameidata nd;
486 int err;
487 struct file *file;
488
Trond Myklebust834f2a42005-10-18 14:20:16 -0700489 err = path_lookup_open(name, LOOKUP_FOLLOW, &nd, FMODE_READ);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 file = ERR_PTR(err);
491
492 if (!err) {
493 struct inode *inode = nd.dentry->d_inode;
494 file = ERR_PTR(-EACCES);
495 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
496 S_ISREG(inode->i_mode)) {
497 int err = permission(inode, MAY_EXEC, &nd);
498 if (!err && !(inode->i_mode & 0111))
499 err = -EACCES;
500 file = ERR_PTR(err);
501 if (!err) {
Trond Myklebust834f2a42005-10-18 14:20:16 -0700502 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (!IS_ERR(file)) {
504 err = deny_write_access(file);
505 if (err) {
506 fput(file);
507 file = ERR_PTR(err);
508 }
509 }
510out:
511 return file;
512 }
513 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700514 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 path_release(&nd);
516 }
517 goto out;
518}
519
520EXPORT_SYMBOL(open_exec);
521
522int kernel_read(struct file *file, unsigned long offset,
523 char *addr, unsigned long count)
524{
525 mm_segment_t old_fs;
526 loff_t pos = offset;
527 int result;
528
529 old_fs = get_fs();
530 set_fs(get_ds());
531 /* The cast to a user pointer is valid due to the set_fs() */
532 result = vfs_read(file, (void __user *)addr, count, &pos);
533 set_fs(old_fs);
534 return result;
535}
536
537EXPORT_SYMBOL(kernel_read);
538
539static int exec_mmap(struct mm_struct *mm)
540{
541 struct task_struct *tsk;
542 struct mm_struct * old_mm, *active_mm;
543
544 /* Notify parent that we're no longer interested in the old VM */
545 tsk = current;
546 old_mm = current->mm;
547 mm_release(tsk, old_mm);
548
549 if (old_mm) {
550 /*
551 * Make sure that if there is a core dump in progress
552 * for the old mm, we get out and die instead of going
553 * through with the exec. We must hold mmap_sem around
554 * checking core_waiters and changing tsk->mm. The
555 * core-inducing thread will increment core_waiters for
556 * each thread whose ->mm == old_mm.
557 */
558 down_read(&old_mm->mmap_sem);
559 if (unlikely(old_mm->core_waiters)) {
560 up_read(&old_mm->mmap_sem);
561 return -EINTR;
562 }
563 }
564 task_lock(tsk);
565 active_mm = tsk->active_mm;
566 tsk->mm = mm;
567 tsk->active_mm = mm;
568 activate_mm(active_mm, mm);
569 task_unlock(tsk);
570 arch_pick_mmap_layout(mm);
571 if (old_mm) {
572 up_read(&old_mm->mmap_sem);
573 if (active_mm != old_mm) BUG();
574 mmput(old_mm);
575 return 0;
576 }
577 mmdrop(active_mm);
578 return 0;
579}
580
581/*
582 * This function makes sure the current process has its own signal table,
583 * so that flush_signal_handlers can later reset the handlers without
584 * disturbing other processes. (Other processes might share the signal
585 * table via the CLONE_SIGHAND option to clone().)
586 */
587static inline int de_thread(struct task_struct *tsk)
588{
589 struct signal_struct *sig = tsk->signal;
590 struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
591 spinlock_t *lock = &oldsighand->siglock;
592 int count;
593
594 /*
595 * If we don't share sighandlers, then we aren't sharing anything
596 * and we can just re-use it all.
597 */
598 if (atomic_read(&oldsighand->count) <= 1) {
599 BUG_ON(atomic_read(&sig->count) != 1);
600 exit_itimers(sig);
601 return 0;
602 }
603
604 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
605 if (!newsighand)
606 return -ENOMEM;
607
608 if (thread_group_empty(current))
609 goto no_thread_group;
610
611 /*
612 * Kill all other threads in the thread group.
613 * We must hold tasklist_lock to call zap_other_threads.
614 */
615 read_lock(&tasklist_lock);
616 spin_lock_irq(lock);
617 if (sig->flags & SIGNAL_GROUP_EXIT) {
618 /*
619 * Another group action in progress, just
620 * return so that the signal is processed.
621 */
622 spin_unlock_irq(lock);
623 read_unlock(&tasklist_lock);
624 kmem_cache_free(sighand_cachep, newsighand);
625 return -EAGAIN;
626 }
627 zap_other_threads(current);
628 read_unlock(&tasklist_lock);
629
630 /*
631 * Account for the thread group leader hanging around:
632 */
Oleg Nesterov9e4e23b2005-10-30 15:01:37 -0800633 count = 1;
634 if (!thread_group_leader(current)) {
635 count = 2;
Roland McGrath53231252005-07-12 13:58:27 -0700636 /*
637 * The SIGALRM timer survives the exec, but needs to point
638 * at us as the new group leader now. We have a race with
639 * a timer firing now getting the old leader, so we need to
640 * synchronize with any firing (by calling del_timer_sync)
641 * before we can safely let the old group leader die.
642 */
643 sig->real_timer.data = (unsigned long)current;
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800644 spin_unlock_irq(lock);
Roland McGrath53231252005-07-12 13:58:27 -0700645 if (del_timer_sync(&sig->real_timer))
646 add_timer(&sig->real_timer);
Oleg Nesterov932aeaf2005-10-30 15:02:17 -0800647 spin_lock_irq(lock);
Roland McGrath53231252005-07-12 13:58:27 -0700648 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 while (atomic_read(&sig->count) > count) {
650 sig->group_exit_task = current;
651 sig->notify_count = count;
652 __set_current_state(TASK_UNINTERRUPTIBLE);
653 spin_unlock_irq(lock);
654 schedule();
655 spin_lock_irq(lock);
656 }
657 sig->group_exit_task = NULL;
658 sig->notify_count = 0;
659 spin_unlock_irq(lock);
660
661 /*
662 * At this point all other threads have exited, all we have to
663 * do is to wait for the thread group leader to become inactive,
664 * and to assume its PID:
665 */
666 if (!thread_group_leader(current)) {
667 struct task_struct *leader = current->group_leader, *parent;
668 struct dentry *proc_dentry1, *proc_dentry2;
669 unsigned long exit_state, ptrace;
670
671 /*
672 * Wait for the thread group leader to be a zombie.
673 * It should already be zombie at this point, most
674 * of the time.
675 */
676 while (leader->exit_state != EXIT_ZOMBIE)
677 yield();
678
679 spin_lock(&leader->proc_lock);
680 spin_lock(&current->proc_lock);
681 proc_dentry1 = proc_pid_unhash(current);
682 proc_dentry2 = proc_pid_unhash(leader);
683 write_lock_irq(&tasklist_lock);
684
Linus Torvaldsc2a0f592005-06-18 13:06:22 -0700685 BUG_ON(leader->tgid != current->tgid);
686 BUG_ON(current->pid == current->tgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 /*
688 * An exec() starts a new thread group with the
689 * TGID of the previous thread group. Rehash the
690 * two threads with a switched PID, and release
691 * the former thread group leader:
692 */
693 ptrace = leader->ptrace;
694 parent = leader->parent;
695 if (unlikely(ptrace) && unlikely(parent == current)) {
696 /*
697 * Joker was ptracing his own group leader,
698 * and now he wants to be his own parent!
699 * We can't have that.
700 */
701 ptrace = 0;
702 }
703
704 ptrace_unlink(current);
705 ptrace_unlink(leader);
706 remove_parent(current);
707 remove_parent(leader);
708
709 switch_exec_pids(leader, current);
710
711 current->parent = current->real_parent = leader->real_parent;
712 leader->parent = leader->real_parent = child_reaper;
713 current->group_leader = current;
714 leader->group_leader = leader;
715
716 add_parent(current, current->parent);
717 add_parent(leader, leader->parent);
718 if (ptrace) {
719 current->ptrace = ptrace;
720 __ptrace_link(current, parent);
721 }
722
723 list_del(&current->tasks);
724 list_add_tail(&current->tasks, &init_task.tasks);
725 current->exit_signal = SIGCHLD;
726 exit_state = leader->exit_state;
727
728 write_unlock_irq(&tasklist_lock);
729 spin_unlock(&leader->proc_lock);
730 spin_unlock(&current->proc_lock);
731 proc_pid_flush(proc_dentry1);
732 proc_pid_flush(proc_dentry2);
733
Linus Torvaldsc2a0f592005-06-18 13:06:22 -0700734 BUG_ON(exit_state != EXIT_ZOMBIE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 release_task(leader);
736 }
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:
745 BUG_ON(atomic_read(&sig->count) != 1);
746 exit_itimers(sig);
747
748 if (atomic_read(&oldsighand->count) == 1) {
749 /*
750 * Now that we nuked the rest of the thread group,
751 * it turns out we are not sharing sighand any more either.
752 * So we can just keep it.
753 */
754 kmem_cache_free(sighand_cachep, newsighand);
755 } else {
756 /*
757 * Move our state over to newsighand and switch it in.
758 */
759 spin_lock_init(&newsighand->siglock);
760 atomic_set(&newsighand->count, 1);
761 memcpy(newsighand->action, oldsighand->action,
762 sizeof(newsighand->action));
763
764 write_lock_irq(&tasklist_lock);
765 spin_lock(&oldsighand->siglock);
766 spin_lock(&newsighand->siglock);
767
768 current->sighand = newsighand;
769 recalc_sigpending();
770
771 spin_unlock(&newsighand->siglock);
772 spin_unlock(&oldsighand->siglock);
773 write_unlock_irq(&tasklist_lock);
774
775 if (atomic_dec_and_test(&oldsighand->count))
776 kmem_cache_free(sighand_cachep, oldsighand);
777 }
778
Linus Torvaldsc2a0f592005-06-18 13:06:22 -0700779 BUG_ON(!thread_group_leader(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 return 0;
781}
782
783/*
784 * These functions flushes out all traces of the currently running executable
785 * so that a new one can be started
786 */
787
788static inline void flush_old_files(struct files_struct * files)
789{
790 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700791 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
793 spin_lock(&files->file_lock);
794 for (;;) {
795 unsigned long set, i;
796
797 j++;
798 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700799 fdt = files_fdtable(files);
800 if (i >= fdt->max_fds || i >= fdt->max_fdset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700802 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 if (!set)
804 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700805 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 spin_unlock(&files->file_lock);
807 for ( ; set ; i++,set >>= 1) {
808 if (set & 1) {
809 sys_close(i);
810 }
811 }
812 spin_lock(&files->file_lock);
813
814 }
815 spin_unlock(&files->file_lock);
816}
817
818void get_task_comm(char *buf, struct task_struct *tsk)
819{
820 /* buf must be at least sizeof(tsk->comm) in size */
821 task_lock(tsk);
822 strncpy(buf, tsk->comm, sizeof(tsk->comm));
823 task_unlock(tsk);
824}
825
826void set_task_comm(struct task_struct *tsk, char *buf)
827{
828 task_lock(tsk);
829 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
830 task_unlock(tsk);
831}
832
833int flush_old_exec(struct linux_binprm * bprm)
834{
835 char * name;
836 int i, ch, retval;
837 struct files_struct *files;
838 char tcomm[sizeof(current->comm)];
839
840 /*
841 * Make sure we have a private signal table and that
842 * we are unassociated from the previous thread group.
843 */
844 retval = de_thread(current);
845 if (retval)
846 goto out;
847
848 /*
849 * Make sure we have private file handles. Ask the
850 * fork helper to do the work for us and the exit
851 * helper to do the cleanup of the old one.
852 */
853 files = current->files; /* refcounted so safe to hold */
854 retval = unshare_files();
855 if (retval)
856 goto out;
857 /*
858 * Release all of the old mmap stuff
859 */
860 retval = exec_mmap(bprm->mm);
861 if (retval)
862 goto mmap_failed;
863
864 bprm->mm = NULL; /* We're using it now */
865
866 /* This is the point of no return */
867 steal_locks(files);
868 put_files_struct(files);
869
870 current->sas_ss_sp = current->sas_ss_size = 0;
871
872 if (current->euid == current->uid && current->egid == current->gid)
873 current->mm->dumpable = 1;
Alan Coxd6e71142005-06-23 00:09:43 -0700874 else
875 current->mm->dumpable = suid_dumpable;
876
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700878
879 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 for (i=0; (ch = *(name++)) != '\0';) {
881 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700882 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 else
884 if (i < (sizeof(tcomm) - 1))
885 tcomm[i++] = ch;
886 }
887 tcomm[i] = '\0';
888 set_task_comm(current, tcomm);
889
890 current->flags &= ~PF_RANDOMIZE;
891 flush_thread();
892
893 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
894 permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
895 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
896 suid_keys(current);
Alan Coxd6e71142005-06-23 00:09:43 -0700897 current->mm->dumpable = suid_dumpable;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 }
899
900 /* An exec changes our domain. We are no longer part of the thread
901 group */
902
903 current->self_exec_id++;
904
905 flush_signal_handlers(current, 0);
906 flush_old_files(current->files);
907
908 return 0;
909
910mmap_failed:
911 put_files_struct(current->files);
912 current->files = files;
913out:
914 return retval;
915}
916
917EXPORT_SYMBOL(flush_old_exec);
918
919/*
920 * Fill the binprm structure from the inode.
921 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
922 */
923int prepare_binprm(struct linux_binprm *bprm)
924{
925 int mode;
926 struct inode * inode = bprm->file->f_dentry->d_inode;
927 int retval;
928
929 mode = inode->i_mode;
930 /*
931 * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
932 * generic_permission lets a non-executable through
933 */
934 if (!(mode & 0111)) /* with at least _one_ execute bit set */
935 return -EACCES;
936 if (bprm->file->f_op == NULL)
937 return -EACCES;
938
939 bprm->e_uid = current->euid;
940 bprm->e_gid = current->egid;
941
942 if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
943 /* Set-uid? */
944 if (mode & S_ISUID) {
945 current->personality &= ~PER_CLEAR_ON_SETID;
946 bprm->e_uid = inode->i_uid;
947 }
948
949 /* Set-gid? */
950 /*
951 * If setgid is set but no group execute bit then this
952 * is a candidate for mandatory locking, not a setgid
953 * executable.
954 */
955 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
956 current->personality &= ~PER_CLEAR_ON_SETID;
957 bprm->e_gid = inode->i_gid;
958 }
959 }
960
961 /* fill in binprm security blob */
962 retval = security_bprm_set(bprm);
963 if (retval)
964 return retval;
965
966 memset(bprm->buf,0,BINPRM_BUF_SIZE);
967 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
968}
969
970EXPORT_SYMBOL(prepare_binprm);
971
972static inline int unsafe_exec(struct task_struct *p)
973{
974 int unsafe = 0;
975 if (p->ptrace & PT_PTRACED) {
976 if (p->ptrace & PT_PTRACE_CAP)
977 unsafe |= LSM_UNSAFE_PTRACE_CAP;
978 else
979 unsafe |= LSM_UNSAFE_PTRACE;
980 }
981 if (atomic_read(&p->fs->count) > 1 ||
982 atomic_read(&p->files->count) > 1 ||
983 atomic_read(&p->sighand->count) > 1)
984 unsafe |= LSM_UNSAFE_SHARE;
985
986 return unsafe;
987}
988
989void compute_creds(struct linux_binprm *bprm)
990{
991 int unsafe;
992
993 if (bprm->e_uid != current->uid)
994 suid_keys(current);
995 exec_keys(current);
996
997 task_lock(current);
998 unsafe = unsafe_exec(current);
999 security_bprm_apply_creds(bprm, unsafe);
1000 task_unlock(current);
1001 security_bprm_post_apply_creds(bprm);
1002}
1003
1004EXPORT_SYMBOL(compute_creds);
1005
1006void remove_arg_zero(struct linux_binprm *bprm)
1007{
1008 if (bprm->argc) {
1009 unsigned long offset;
1010 char * kaddr;
1011 struct page *page;
1012
1013 offset = bprm->p % PAGE_SIZE;
1014 goto inside;
1015
1016 while (bprm->p++, *(kaddr+offset++)) {
1017 if (offset != PAGE_SIZE)
1018 continue;
1019 offset = 0;
1020 kunmap_atomic(kaddr, KM_USER0);
1021inside:
1022 page = bprm->page[bprm->p/PAGE_SIZE];
1023 kaddr = kmap_atomic(page, KM_USER0);
1024 }
1025 kunmap_atomic(kaddr, KM_USER0);
1026 bprm->argc--;
1027 }
1028}
1029
1030EXPORT_SYMBOL(remove_arg_zero);
1031
1032/*
1033 * cycle the list of binary formats handler, until one recognizes the image
1034 */
1035int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1036{
1037 int try,retval;
1038 struct linux_binfmt *fmt;
1039#ifdef __alpha__
1040 /* handle /sbin/loader.. */
1041 {
1042 struct exec * eh = (struct exec *) bprm->buf;
1043
1044 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1045 (eh->fh.f_flags & 0x3000) == 0x3000)
1046 {
1047 struct file * file;
1048 unsigned long loader;
1049
1050 allow_write_access(bprm->file);
1051 fput(bprm->file);
1052 bprm->file = NULL;
1053
1054 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1055
1056 file = open_exec("/sbin/loader");
1057 retval = PTR_ERR(file);
1058 if (IS_ERR(file))
1059 return retval;
1060
1061 /* Remember if the application is TASO. */
1062 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1063
1064 bprm->file = file;
1065 bprm->loader = loader;
1066 retval = prepare_binprm(bprm);
1067 if (retval<0)
1068 return retval;
1069 /* should call search_binary_handler recursively here,
1070 but it does not matter */
1071 }
1072 }
1073#endif
1074 retval = security_bprm_check(bprm);
1075 if (retval)
1076 return retval;
1077
1078 /* kernel module loader fixup */
1079 /* so we don't try to load run modprobe in kernel space. */
1080 set_fs(USER_DS);
1081 retval = -ENOENT;
1082 for (try=0; try<2; try++) {
1083 read_lock(&binfmt_lock);
1084 for (fmt = formats ; fmt ; fmt = fmt->next) {
1085 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1086 if (!fn)
1087 continue;
1088 if (!try_module_get(fmt->module))
1089 continue;
1090 read_unlock(&binfmt_lock);
1091 retval = fn(bprm, regs);
1092 if (retval >= 0) {
1093 put_binfmt(fmt);
1094 allow_write_access(bprm->file);
1095 if (bprm->file)
1096 fput(bprm->file);
1097 bprm->file = NULL;
1098 current->did_exec = 1;
1099 return retval;
1100 }
1101 read_lock(&binfmt_lock);
1102 put_binfmt(fmt);
1103 if (retval != -ENOEXEC || bprm->mm == NULL)
1104 break;
1105 if (!bprm->file) {
1106 read_unlock(&binfmt_lock);
1107 return retval;
1108 }
1109 }
1110 read_unlock(&binfmt_lock);
1111 if (retval != -ENOEXEC || bprm->mm == NULL) {
1112 break;
1113#ifdef CONFIG_KMOD
1114 }else{
1115#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1116 if (printable(bprm->buf[0]) &&
1117 printable(bprm->buf[1]) &&
1118 printable(bprm->buf[2]) &&
1119 printable(bprm->buf[3]))
1120 break; /* -ENOEXEC */
1121 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1122#endif
1123 }
1124 }
1125 return retval;
1126}
1127
1128EXPORT_SYMBOL(search_binary_handler);
1129
1130/*
1131 * sys_execve() executes a new program.
1132 */
1133int do_execve(char * filename,
1134 char __user *__user *argv,
1135 char __user *__user *envp,
1136 struct pt_regs * regs)
1137{
1138 struct linux_binprm *bprm;
1139 struct file *file;
1140 int retval;
1141 int i;
1142
1143 retval = -ENOMEM;
1144 bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
1145 if (!bprm)
1146 goto out_ret;
1147 memset(bprm, 0, sizeof(*bprm));
1148
1149 file = open_exec(filename);
1150 retval = PTR_ERR(file);
1151 if (IS_ERR(file))
1152 goto out_kfree;
1153
1154 sched_exec();
1155
1156 bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1157
1158 bprm->file = file;
1159 bprm->filename = filename;
1160 bprm->interp = filename;
1161 bprm->mm = mm_alloc();
1162 retval = -ENOMEM;
1163 if (!bprm->mm)
1164 goto out_file;
1165
1166 retval = init_new_context(current, bprm->mm);
1167 if (retval < 0)
1168 goto out_mm;
1169
1170 bprm->argc = count(argv, bprm->p / sizeof(void *));
1171 if ((retval = bprm->argc) < 0)
1172 goto out_mm;
1173
1174 bprm->envc = count(envp, bprm->p / sizeof(void *));
1175 if ((retval = bprm->envc) < 0)
1176 goto out_mm;
1177
1178 retval = security_bprm_alloc(bprm);
1179 if (retval)
1180 goto out;
1181
1182 retval = prepare_binprm(bprm);
1183 if (retval < 0)
1184 goto out;
1185
1186 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1187 if (retval < 0)
1188 goto out;
1189
1190 bprm->exec = bprm->p;
1191 retval = copy_strings(bprm->envc, envp, bprm);
1192 if (retval < 0)
1193 goto out;
1194
1195 retval = copy_strings(bprm->argc, argv, bprm);
1196 if (retval < 0)
1197 goto out;
1198
1199 retval = search_binary_handler(bprm,regs);
1200 if (retval >= 0) {
1201 free_arg_pages(bprm);
1202
1203 /* execve success */
1204 security_bprm_free(bprm);
1205 acct_update_integrals(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 kfree(bprm);
1207 return retval;
1208 }
1209
1210out:
1211 /* Something went wrong, return the inode and free the argument pages*/
1212 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1213 struct page * page = bprm->page[i];
1214 if (page)
1215 __free_page(page);
1216 }
1217
1218 if (bprm->security)
1219 security_bprm_free(bprm);
1220
1221out_mm:
1222 if (bprm->mm)
1223 mmdrop(bprm->mm);
1224
1225out_file:
1226 if (bprm->file) {
1227 allow_write_access(bprm->file);
1228 fput(bprm->file);
1229 }
1230
1231out_kfree:
1232 kfree(bprm);
1233
1234out_ret:
1235 return retval;
1236}
1237
1238int set_binfmt(struct linux_binfmt *new)
1239{
1240 struct linux_binfmt *old = current->binfmt;
1241
1242 if (new) {
1243 if (!try_module_get(new->module))
1244 return -1;
1245 }
1246 current->binfmt = new;
1247 if (old)
1248 module_put(old->module);
1249 return 0;
1250}
1251
1252EXPORT_SYMBOL(set_binfmt);
1253
1254#define CORENAME_MAX_SIZE 64
1255
1256/* format_corename will inspect the pattern parameter, and output a
1257 * name into corename, which must have space for at least
1258 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1259 */
1260static void format_corename(char *corename, const char *pattern, long signr)
1261{
1262 const char *pat_ptr = pattern;
1263 char *out_ptr = corename;
1264 char *const out_end = corename + CORENAME_MAX_SIZE;
1265 int rc;
1266 int pid_in_pattern = 0;
1267
1268 /* Repeat as long as we have more pattern to process and more output
1269 space */
1270 while (*pat_ptr) {
1271 if (*pat_ptr != '%') {
1272 if (out_ptr == out_end)
1273 goto out;
1274 *out_ptr++ = *pat_ptr++;
1275 } else {
1276 switch (*++pat_ptr) {
1277 case 0:
1278 goto out;
1279 /* Double percent, output one percent */
1280 case '%':
1281 if (out_ptr == out_end)
1282 goto out;
1283 *out_ptr++ = '%';
1284 break;
1285 /* pid */
1286 case 'p':
1287 pid_in_pattern = 1;
1288 rc = snprintf(out_ptr, out_end - out_ptr,
1289 "%d", current->tgid);
1290 if (rc > out_end - out_ptr)
1291 goto out;
1292 out_ptr += rc;
1293 break;
1294 /* uid */
1295 case 'u':
1296 rc = snprintf(out_ptr, out_end - out_ptr,
1297 "%d", current->uid);
1298 if (rc > out_end - out_ptr)
1299 goto out;
1300 out_ptr += rc;
1301 break;
1302 /* gid */
1303 case 'g':
1304 rc = snprintf(out_ptr, out_end - out_ptr,
1305 "%d", current->gid);
1306 if (rc > out_end - out_ptr)
1307 goto out;
1308 out_ptr += rc;
1309 break;
1310 /* signal that caused the coredump */
1311 case 's':
1312 rc = snprintf(out_ptr, out_end - out_ptr,
1313 "%ld", signr);
1314 if (rc > out_end - out_ptr)
1315 goto out;
1316 out_ptr += rc;
1317 break;
1318 /* UNIX time of coredump */
1319 case 't': {
1320 struct timeval tv;
1321 do_gettimeofday(&tv);
1322 rc = snprintf(out_ptr, out_end - out_ptr,
1323 "%lu", tv.tv_sec);
1324 if (rc > out_end - out_ptr)
1325 goto out;
1326 out_ptr += rc;
1327 break;
1328 }
1329 /* hostname */
1330 case 'h':
1331 down_read(&uts_sem);
1332 rc = snprintf(out_ptr, out_end - out_ptr,
1333 "%s", system_utsname.nodename);
1334 up_read(&uts_sem);
1335 if (rc > out_end - out_ptr)
1336 goto out;
1337 out_ptr += rc;
1338 break;
1339 /* executable */
1340 case 'e':
1341 rc = snprintf(out_ptr, out_end - out_ptr,
1342 "%s", current->comm);
1343 if (rc > out_end - out_ptr)
1344 goto out;
1345 out_ptr += rc;
1346 break;
1347 default:
1348 break;
1349 }
1350 ++pat_ptr;
1351 }
1352 }
1353 /* Backward compatibility with core_uses_pid:
1354 *
1355 * If core_pattern does not include a %p (as is the default)
1356 * and core_uses_pid is set, then .%pid will be appended to
1357 * the filename */
1358 if (!pid_in_pattern
1359 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1360 rc = snprintf(out_ptr, out_end - out_ptr,
1361 ".%d", current->tgid);
1362 if (rc > out_end - out_ptr)
1363 goto out;
1364 out_ptr += rc;
1365 }
1366 out:
1367 *out_ptr = 0;
1368}
1369
1370static void zap_threads (struct mm_struct *mm)
1371{
1372 struct task_struct *g, *p;
1373 struct task_struct *tsk = current;
1374 struct completion *vfork_done = tsk->vfork_done;
1375 int traced = 0;
1376
1377 /*
1378 * Make sure nobody is waiting for us to release the VM,
1379 * otherwise we can deadlock when we wait on each other
1380 */
1381 if (vfork_done) {
1382 tsk->vfork_done = NULL;
1383 complete(vfork_done);
1384 }
1385
1386 read_lock(&tasklist_lock);
1387 do_each_thread(g,p)
1388 if (mm == p->mm && p != tsk) {
1389 force_sig_specific(SIGKILL, p);
1390 mm->core_waiters++;
1391 if (unlikely(p->ptrace) &&
1392 unlikely(p->parent->mm == mm))
1393 traced = 1;
1394 }
1395 while_each_thread(g,p);
1396
1397 read_unlock(&tasklist_lock);
1398
1399 if (unlikely(traced)) {
1400 /*
1401 * We are zapping a thread and the thread it ptraces.
1402 * If the tracee went into a ptrace stop for exit tracing,
1403 * we could deadlock since the tracer is waiting for this
1404 * coredump to finish. Detach them so they can both die.
1405 */
1406 write_lock_irq(&tasklist_lock);
1407 do_each_thread(g,p) {
1408 if (mm == p->mm && p != tsk &&
1409 p->ptrace && p->parent->mm == mm) {
1410 __ptrace_unlink(p);
1411 }
1412 } while_each_thread(g,p);
1413 write_unlock_irq(&tasklist_lock);
1414 }
1415}
1416
1417static void coredump_wait(struct mm_struct *mm)
1418{
1419 DECLARE_COMPLETION(startup_done);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001420 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422 mm->core_startup_done = &startup_done;
1423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 zap_threads(mm);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001425 core_waiters = mm->core_waiters;
1426 up_write(&mm->mmap_sem);
1427
1428 if (core_waiters)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429 wait_for_completion(&startup_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 BUG_ON(mm->core_waiters);
1431}
1432
1433int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1434{
1435 char corename[CORENAME_MAX_SIZE + 1];
1436 struct mm_struct *mm = current->mm;
1437 struct linux_binfmt * binfmt;
1438 struct inode * inode;
1439 struct file * file;
1440 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001441 int fsuid = current->fsuid;
1442 int flag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443
1444 binfmt = current->binfmt;
1445 if (!binfmt || !binfmt->core_dump)
1446 goto fail;
1447 down_write(&mm->mmap_sem);
1448 if (!mm->dumpable) {
1449 up_write(&mm->mmap_sem);
1450 goto fail;
1451 }
Alan Coxd6e71142005-06-23 00:09:43 -07001452
1453 /*
1454 * We cannot trust fsuid as being the "true" uid of the
1455 * process nor do we know its entire history. We only know it
1456 * was tainted so we dump it as root in mode 2.
1457 */
1458 if (mm->dumpable == 2) { /* Setuid core dump mode */
1459 flag = O_EXCL; /* Stop rewrite attacks */
1460 current->fsuid = 0; /* Dump root private */
1461 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 mm->dumpable = 0;
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001463
1464 retval = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001466 if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
1467 current->signal->flags = SIGNAL_GROUP_EXIT;
1468 current->signal->group_exit_code = exit_code;
1469 retval = 0;
1470 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 spin_unlock_irq(&current->sighand->siglock);
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001472 if (retval) {
1473 up_write(&mm->mmap_sem);
1474 goto fail;
1475 }
1476
1477 init_completion(&mm->core_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 coredump_wait(mm);
1479
1480 /*
1481 * Clear any false indication of pending signals that might
1482 * be seen by the filesystem code called to write the core file.
1483 */
1484 current->signal->group_stop_count = 0;
1485 clear_thread_flag(TIF_SIGPENDING);
1486
1487 if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1488 goto fail_unlock;
1489
1490 /*
1491 * lock_kernel() because format_corename() is controlled by sysctl, which
1492 * uses lock_kernel()
1493 */
1494 lock_kernel();
1495 format_corename(corename, core_pattern, signr);
1496 unlock_kernel();
Alan Coxd6e71142005-06-23 00:09:43 -07001497 file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498 if (IS_ERR(file))
1499 goto fail_unlock;
1500 inode = file->f_dentry->d_inode;
1501 if (inode->i_nlink > 1)
1502 goto close_fail; /* multiple links - don't dump */
1503 if (d_unhashed(file->f_dentry))
1504 goto close_fail;
1505
1506 if (!S_ISREG(inode->i_mode))
1507 goto close_fail;
1508 if (!file->f_op)
1509 goto close_fail;
1510 if (!file->f_op->write)
1511 goto close_fail;
1512 if (do_truncate(file->f_dentry, 0) != 0)
1513 goto close_fail;
1514
1515 retval = binfmt->core_dump(signr, regs, file);
1516
1517 if (retval)
1518 current->signal->group_exit_code |= 0x80;
1519close_fail:
1520 filp_close(file, NULL);
1521fail_unlock:
Alan Coxd6e71142005-06-23 00:09:43 -07001522 current->fsuid = fsuid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 complete_all(&mm->core_done);
1524fail:
1525 return retval;
1526}