projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
[PATCH] split linux/file.h
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / exec.c
1 /*
2 * linux/fs/exec.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 /*
8 * #!-checking implemented by tytso.
9 */
10 /*
11 * Demand-loading implemented 01.12.91 - no need to read anything but
12 * the header into memory. The inode of the executable is put into
13 * "current->executable", and page faults do the actual loading. Clean.
14 *
15 * Once more I can proudly say that linux stood up to being changed: it
16 * was less than 2 hours work to get demand-loading completely implemented.
17 *
18 * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead,
19 * current->executable is only used by the procfs. This allows a dispatch
20 * table to check for several different types of binary formats. We keep
21 * trying until we recognize the file or we run out of supported binary
22 * formats.
23 */
24
25 #include <linux/slab.h>
26 #include <linux/file.h>
27 #include <linux/fdtable.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/string.h>
34 #include <linux/init.h>
35 #include <linux/pagemap.h>
36 #include <linux/highmem.h>
37 #include <linux/spinlock.h>
38 #include <linux/key.h>
39 #include <linux/personality.h>
40 #include <linux/binfmts.h>
41 #include <linux/swap.h>
42 #include <linux/utsname.h>
43 #include <linux/pid_namespace.h>
44 #include <linux/module.h>
45 #include <linux/namei.h>
46 #include <linux/proc_fs.h>
47 #include <linux/ptrace.h>
48 #include <linux/mount.h>
49 #include <linux/security.h>
50 #include <linux/syscalls.h>
51 #include <linux/rmap.h>
52 #include <linux/tsacct_kern.h>
53 #include <linux/cn_proc.h>
54 #include <linux/audit.h>
55
56 #include <asm/uaccess.h>
57 #include <asm/mmu_context.h>
58 #include <asm/tlb.h>
59
60 #ifdef CONFIG_KMOD
61 #include <linux/kmod.h>
62 #endif
63
64 int core_uses_pid;
65 char core_pattern[CORENAME_MAX_SIZE] = "core";
66 int suid_dumpable = 0;
67
68 /* The maximal length of core_pattern is also specified in sysctl.c */
69
70 static LIST_HEAD(formats);
71 static DEFINE_RWLOCK(binfmt_lock);
72
73 int register_binfmt(struct linux_binfmt * fmt)
74 {
75 if (!fmt)
76 return -EINVAL;
77 write_lock(&binfmt_lock);
78 list_add(&fmt->lh, &formats);
79 write_unlock(&binfmt_lock);
80 return 0;
81 }
82
83 EXPORT_SYMBOL(register_binfmt);
84
85 void unregister_binfmt(struct linux_binfmt * fmt)
86 {
87 write_lock(&binfmt_lock);
88 list_del(&fmt->lh);
89 write_unlock(&binfmt_lock);
90 }
91
92 EXPORT_SYMBOL(unregister_binfmt);
93
94 static inline void put_binfmt(struct linux_binfmt * fmt)
95 {
96 module_put(fmt->module);
97 }
98
99 /*
100 * Note that a shared library must be both readable and executable due to
101 * security reasons.
102 *
103 * Also note that we take the address to load from from the file itself.
104 */
105 asmlinkage long sys_uselib(const char __user * library)
106 {
107 struct file * file;
108 struct nameidata nd;
109 int error;
110
111 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
112 if (error)
113 goto out;
114
115 error = -EINVAL;
116 if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
117 goto exit;
118
119 error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
120 if (error)
121 goto exit;
122
123 file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
124 error = PTR_ERR(file);
125 if (IS_ERR(file))
126 goto out;
127
128 error = -ENOEXEC;
129 if(file->f_op) {
130 struct linux_binfmt * fmt;
131
132 read_lock(&binfmt_lock);
133 list_for_each_entry(fmt, &formats, lh) {
134 if (!fmt->load_shlib)
135 continue;
136 if (!try_module_get(fmt->module))
137 continue;
138 read_unlock(&binfmt_lock);
139 error = fmt->load_shlib(file);
140 read_lock(&binfmt_lock);
141 put_binfmt(fmt);
142 if (error != -ENOEXEC)
143 break;
144 }
145 read_unlock(&binfmt_lock);
146 }
147 fput(file);
148 out:
149 return error;
150 exit:
151 release_open_intent(&nd);
152 path_put(&nd.path);
153 goto out;
154 }
155
156 #ifdef CONFIG_MMU
157
158 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
159 int write)
160 {
161 struct page *page;
162 int ret;
163
164 #ifdef CONFIG_STACK_GROWSUP
165 if (write) {
166 ret = expand_stack_downwards(bprm->vma, pos);
167 if (ret < 0)
168 return NULL;
169 }
170 #endif
171 ret = get_user_pages(current, bprm->mm, pos,
172 1, write, 1, &page, NULL);
173 if (ret <= 0)
174 return NULL;
175
176 if (write) {
177 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
178 struct rlimit *rlim;
179
180 /*
181 * We've historically supported up to 32 pages (ARG_MAX)
182 * of argument strings even with small stacks
183 */
184 if (size <= ARG_MAX)
185 return page;
186
187 /*
188 * Limit to 1/4-th the stack size for the argv+env strings.
189 * This ensures that:
190 * - the remaining binfmt code will not run out of stack space,
191 * - the program will have a reasonable amount of stack left
192 * to work from.
193 */
194 rlim = current->signal->rlim;
195 if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
196 put_page(page);
197 return NULL;
198 }
199 }
200
201 return page;
202 }
203
204 static void put_arg_page(struct page *page)
205 {
206 put_page(page);
207 }
208
209 static void free_arg_page(struct linux_binprm *bprm, int i)
210 {
211 }
212
213 static void free_arg_pages(struct linux_binprm *bprm)
214 {
215 }
216
217 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
218 struct page *page)
219 {
220 flush_cache_page(bprm->vma, pos, page_to_pfn(page));
221 }
222
223 static int __bprm_mm_init(struct linux_binprm *bprm)
224 {
225 int err = -ENOMEM;
226 struct vm_area_struct *vma = NULL;
227 struct mm_struct *mm = bprm->mm;
228
229 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
230 if (!vma)
231 goto err;
232
233 down_write(&mm->mmap_sem);
234 vma->vm_mm = mm;
235
236 /*
237 * Place the stack at the largest stack address the architecture
238 * supports. Later, we'll move this to an appropriate place. We don't
239 * use STACK_TOP because that can depend on attributes which aren't
240 * configured yet.
241 */
242 vma->vm_end = STACK_TOP_MAX;
243 vma->vm_start = vma->vm_end - PAGE_SIZE;
244
245 vma->vm_flags = VM_STACK_FLAGS;
246 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
247 err = insert_vm_struct(mm, vma);
248 if (err) {
249 up_write(&mm->mmap_sem);
250 goto err;
251 }
252
253 mm->stack_vm = mm->total_vm = 1;
254 up_write(&mm->mmap_sem);
255
256 bprm->p = vma->vm_end - sizeof(void *);
257
258 return 0;
259
260 err:
261 if (vma) {
262 bprm->vma = NULL;
263 kmem_cache_free(vm_area_cachep, vma);
264 }
265
266 return err;
267 }
268
269 static bool valid_arg_len(struct linux_binprm *bprm, long len)
270 {
271 return len <= MAX_ARG_STRLEN;
272 }
273
274 #else
275
276 static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
277 int write)
278 {
279 struct page *page;
280
281 page = bprm->page[pos / PAGE_SIZE];
282 if (!page && write) {
283 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
284 if (!page)
285 return NULL;
286 bprm->page[pos / PAGE_SIZE] = page;
287 }
288
289 return page;
290 }
291
292 static void put_arg_page(struct page *page)
293 {
294 }
295
296 static void free_arg_page(struct linux_binprm *bprm, int i)
297 {
298 if (bprm->page[i]) {
299 __free_page(bprm->page[i]);
300 bprm->page[i] = NULL;
301 }
302 }
303
304 static void free_arg_pages(struct linux_binprm *bprm)
305 {
306 int i;
307
308 for (i = 0; i < MAX_ARG_PAGES; i++)
309 free_arg_page(bprm, i);
310 }
311
312 static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
313 struct page *page)
314 {
315 }
316
317 static int __bprm_mm_init(struct linux_binprm *bprm)
318 {
319 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
320 return 0;
321 }
322
323 static bool valid_arg_len(struct linux_binprm *bprm, long len)
324 {
325 return len <= bprm->p;
326 }
327
328 #endif /* CONFIG_MMU */
329
330 /*
331 * Create a new mm_struct and populate it with a temporary stack
332 * vm_area_struct. We don't have enough context at this point to set the stack
333 * flags, permissions, and offset, so we use temporary values. We'll update
334 * them later in setup_arg_pages().
335 */
336 int bprm_mm_init(struct linux_binprm *bprm)
337 {
338 int err;
339 struct mm_struct *mm = NULL;
340
341 bprm->mm = mm = mm_alloc();
342 err = -ENOMEM;
343 if (!mm)
344 goto err;
345
346 err = init_new_context(current, mm);
347 if (err)
348 goto err;
349
350 err = __bprm_mm_init(bprm);
351 if (err)
352 goto err;
353
354 return 0;
355
356 err:
357 if (mm) {
358 bprm->mm = NULL;
359 mmdrop(mm);
360 }
361
362 return err;
363 }
364
365 /*
366 * count() counts the number of strings in array ARGV.
367 */
368 static int count(char __user * __user * argv, int max)
369 {
370 int i = 0;
371
372 if (argv != NULL) {
373 for (;;) {
374 char __user * p;
375
376 if (get_user(p, argv))
377 return -EFAULT;
378 if (!p)
379 break;
380 argv++;
381 if(++i > max)
382 return -E2BIG;
383 cond_resched();
384 }
385 }
386 return i;
387 }
388
389 /*
390 * 'copy_strings()' copies argument/environment strings from the old
391 * processes's memory to the new process's stack. The call to get_user_pages()
392 * ensures the destination page is created and not swapped out.
393 */
394 static int copy_strings(int argc, char __user * __user * argv,
395 struct linux_binprm *bprm)
396 {
397 struct page *kmapped_page = NULL;
398 char *kaddr = NULL;
399 unsigned long kpos = 0;
400 int ret;
401
402 while (argc-- > 0) {
403 char __user *str;
404 int len;
405 unsigned long pos;
406
407 if (get_user(str, argv+argc) ||
408 !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
409 ret = -EFAULT;
410 goto out;
411 }
412
413 if (!valid_arg_len(bprm, len)) {
414 ret = -E2BIG;
415 goto out;
416 }
417
418 /* We're going to work our way backwords. */
419 pos = bprm->p;
420 str += len;
421 bprm->p -= len;
422
423 while (len > 0) {
424 int offset, bytes_to_copy;
425
426 offset = pos % PAGE_SIZE;
427 if (offset == 0)
428 offset = PAGE_SIZE;
429
430 bytes_to_copy = offset;
431 if (bytes_to_copy > len)
432 bytes_to_copy = len;
433
434 offset -= bytes_to_copy;
435 pos -= bytes_to_copy;
436 str -= bytes_to_copy;
437 len -= bytes_to_copy;
438
439 if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
440 struct page *page;
441
442 page = get_arg_page(bprm, pos, 1);
443 if (!page) {
444 ret = -E2BIG;
445 goto out;
446 }
447
448 if (kmapped_page) {
449 flush_kernel_dcache_page(kmapped_page);
450 kunmap(kmapped_page);
451 put_arg_page(kmapped_page);
452 }
453 kmapped_page = page;
454 kaddr = kmap(kmapped_page);
455 kpos = pos & PAGE_MASK;
456 flush_arg_page(bprm, kpos, kmapped_page);
457 }
458 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
459 ret = -EFAULT;
460 goto out;
461 }
462 }
463 }
464 ret = 0;
465 out:
466 if (kmapped_page) {
467 flush_kernel_dcache_page(kmapped_page);
468 kunmap(kmapped_page);
469 put_arg_page(kmapped_page);
470 }
471 return ret;
472 }
473
474 /*
475 * Like copy_strings, but get argv and its values from kernel memory.
476 */
477 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
478 {
479 int r;
480 mm_segment_t oldfs = get_fs();
481 set_fs(KERNEL_DS);
482 r = copy_strings(argc, (char __user * __user *)argv, bprm);
483 set_fs(oldfs);
484 return r;
485 }
486 EXPORT_SYMBOL(copy_strings_kernel);
487
488 #ifdef CONFIG_MMU
489
490 /*
491 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
492 * the binfmt code determines where the new stack should reside, we shift it to
493 * its final location. The process proceeds as follows:
494 *
495 * 1) Use shift to calculate the new vma endpoints.
496 * 2) Extend vma to cover both the old and new ranges. This ensures the
497 * arguments passed to subsequent functions are consistent.
498 * 3) Move vma's page tables to the new range.
499 * 4) Free up any cleared pgd range.
500 * 5) Shrink the vma to cover only the new range.
501 */
502 static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
503 {
504 struct mm_struct *mm = vma->vm_mm;
505 unsigned long old_start = vma->vm_start;
506 unsigned long old_end = vma->vm_end;
507 unsigned long length = old_end - old_start;
508 unsigned long new_start = old_start - shift;
509 unsigned long new_end = old_end - shift;
510 struct mmu_gather *tlb;
511
512 BUG_ON(new_start > new_end);
513
514 /*
515 * ensure there are no vmas between where we want to go
516 * and where we are
517 */
518 if (vma != find_vma(mm, new_start))
519 return -EFAULT;
520
521 /*
522 * cover the whole range: [new_start, old_end)
523 */
524 vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
525
526 /*
527 * move the page tables downwards, on failure we rely on
528 * process cleanup to remove whatever mess we made.
529 */
530 if (length != move_page_tables(vma, old_start,
531 vma, new_start, length))
532 return -ENOMEM;
533
534 lru_add_drain();
535 tlb = tlb_gather_mmu(mm, 0);
536 if (new_end > old_start) {
537 /*
538 * when the old and new regions overlap clear from new_end.
539 */
540 free_pgd_range(&tlb, new_end, old_end, new_end,
541 vma->vm_next ? vma->vm_next->vm_start : 0);
542 } else {
543 /*
544 * otherwise, clean from old_start; this is done to not touch
545 * the address space in [new_end, old_start) some architectures
546 * have constraints on va-space that make this illegal (IA64) -
547 * for the others its just a little faster.
548 */
549 free_pgd_range(&tlb, old_start, old_end, new_end,
550 vma->vm_next ? vma->vm_next->vm_start : 0);
551 }
552 tlb_finish_mmu(tlb, new_end, old_end);
553
554 /*
555 * shrink the vma to just the new range.
556 */
557 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
558
559 return 0;
560 }
561
562 #define EXTRA_STACK_VM_PAGES 20 /* random */
563
564 /*
565 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
566 * the stack is optionally relocated, and some extra space is added.
567 */
568 int setup_arg_pages(struct linux_binprm *bprm,
569 unsigned long stack_top,
570 int executable_stack)
571 {
572 unsigned long ret;
573 unsigned long stack_shift;
574 struct mm_struct *mm = current->mm;
575 struct vm_area_struct *vma = bprm->vma;
576 struct vm_area_struct *prev = NULL;
577 unsigned long vm_flags;
578 unsigned long stack_base;
579
580 #ifdef CONFIG_STACK_GROWSUP
581 /* Limit stack size to 1GB */
582 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
583 if (stack_base > (1 << 30))
584 stack_base = 1 << 30;
585
586 /* Make sure we didn't let the argument array grow too large. */
587 if (vma->vm_end - vma->vm_start > stack_base)
588 return -ENOMEM;
589
590 stack_base = PAGE_ALIGN(stack_top - stack_base);
591
592 stack_shift = vma->vm_start - stack_base;
593 mm->arg_start = bprm->p - stack_shift;
594 bprm->p = vma->vm_end - stack_shift;
595 #else
596 stack_top = arch_align_stack(stack_top);
597 stack_top = PAGE_ALIGN(stack_top);
598 stack_shift = vma->vm_end - stack_top;
599
600 bprm->p -= stack_shift;
601 mm->arg_start = bprm->p;
602 #endif
603
604 if (bprm->loader)
605 bprm->loader -= stack_shift;
606 bprm->exec -= stack_shift;
607
608 down_write(&mm->mmap_sem);
609 vm_flags = vma->vm_flags;
610
611 /*
612 * Adjust stack execute permissions; explicitly enable for
613 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
614 * (arch default) otherwise.
615 */
616 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
617 vm_flags |= VM_EXEC;
618 else if (executable_stack == EXSTACK_DISABLE_X)
619 vm_flags &= ~VM_EXEC;
620 vm_flags |= mm->def_flags;
621
622 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
623 vm_flags);
624 if (ret)
625 goto out_unlock;
626 BUG_ON(prev != vma);
627
628 /* Move stack pages down in memory. */
629 if (stack_shift) {
630 ret = shift_arg_pages(vma, stack_shift);
631 if (ret) {
632 up_write(&mm->mmap_sem);
633 return ret;
634 }
635 }
636
637 #ifdef CONFIG_STACK_GROWSUP
638 stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
639 #else
640 stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
641 #endif
642 ret = expand_stack(vma, stack_base);
643 if (ret)
644 ret = -EFAULT;
645
646 out_unlock:
647 up_write(&mm->mmap_sem);
648 return 0;
649 }
650 EXPORT_SYMBOL(setup_arg_pages);
651
652 #endif /* CONFIG_MMU */
653
654 struct file *open_exec(const char *name)
655 {
656 struct nameidata nd;
657 int err;
658 struct file *file;
659
660 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
661 file = ERR_PTR(err);
662
663 if (!err) {
664 struct inode *inode = nd.path.dentry->d_inode;
665 file = ERR_PTR(-EACCES);
666 if (S_ISREG(inode->i_mode)) {
667 int err = vfs_permission(&nd, MAY_EXEC);
668 file = ERR_PTR(err);
669 if (!err) {
670 file = nameidata_to_filp(&nd,
671 O_RDONLY|O_LARGEFILE);
672 if (!IS_ERR(file)) {
673 err = deny_write_access(file);
674 if (err) {
675 fput(file);
676 file = ERR_PTR(err);
677 }
678 }
679 out:
680 return file;
681 }
682 }
683 release_open_intent(&nd);
684 path_put(&nd.path);
685 }
686 goto out;
687 }
688
689 EXPORT_SYMBOL(open_exec);
690
691 int kernel_read(struct file *file, unsigned long offset,
692 char *addr, unsigned long count)
693 {
694 mm_segment_t old_fs;
695 loff_t pos = offset;
696 int result;
697
698 old_fs = get_fs();
699 set_fs(get_ds());
700 /* The cast to a user pointer is valid due to the set_fs() */
701 result = vfs_read(file, (void __user *)addr, count, &pos);
702 set_fs(old_fs);
703 return result;
704 }
705
706 EXPORT_SYMBOL(kernel_read);
707
708 static int exec_mmap(struct mm_struct *mm)
709 {
710 struct task_struct *tsk;
711 struct mm_struct * old_mm, *active_mm;
712
713 /* Notify parent that we're no longer interested in the old VM */
714 tsk = current;
715 old_mm = current->mm;
716 mm_release(tsk, old_mm);
717
718 if (old_mm) {
719 /*
720 * Make sure that if there is a core dump in progress
721 * for the old mm, we get out and die instead of going
722 * through with the exec. We must hold mmap_sem around
723 * checking core_waiters and changing tsk->mm. The
724 * core-inducing thread will increment core_waiters for
725 * each thread whose ->mm == old_mm.
726 */
727 down_read(&old_mm->mmap_sem);
728 if (unlikely(old_mm->core_waiters)) {
729 up_read(&old_mm->mmap_sem);
730 return -EINTR;
731 }
732 }
733 task_lock(tsk);
734 active_mm = tsk->active_mm;
735 tsk->mm = mm;
736 tsk->active_mm = mm;
737 activate_mm(active_mm, mm);
738 task_unlock(tsk);
739 mm_update_next_owner(mm);
740 arch_pick_mmap_layout(mm);
741 if (old_mm) {
742 up_read(&old_mm->mmap_sem);
743 BUG_ON(active_mm != old_mm);
744 mmput(old_mm);
745 return 0;
746 }
747 mmdrop(active_mm);
748 return 0;
749 }
750
751 /*
752 * This function makes sure the current process has its own signal table,
753 * so that flush_signal_handlers can later reset the handlers without
754 * disturbing other processes. (Other processes might share the signal
755 * table via the CLONE_SIGHAND option to clone().)
756 */
757 static int de_thread(struct task_struct *tsk)
758 {
759 struct signal_struct *sig = tsk->signal;
760 struct sighand_struct *oldsighand = tsk->sighand;
761 spinlock_t *lock = &oldsighand->siglock;
762 struct task_struct *leader = NULL;
763 int count;
764
765 if (thread_group_empty(tsk))
766 goto no_thread_group;
767
768 /*
769 * Kill all other threads in the thread group.
770 */
771 spin_lock_irq(lock);
772 if (signal_group_exit(sig)) {
773 /*
774 * Another group action in progress, just
775 * return so that the signal is processed.
776 */
777 spin_unlock_irq(lock);
778 return -EAGAIN;
779 }
780 sig->group_exit_task = tsk;
781 zap_other_threads(tsk);
782
783 /* Account for the thread group leader hanging around: */
784 count = thread_group_leader(tsk) ? 1 : 2;
785 sig->notify_count = count;
786 while (atomic_read(&sig->count) > count) {
787 __set_current_state(TASK_UNINTERRUPTIBLE);
788 spin_unlock_irq(lock);
789 schedule();
790 spin_lock_irq(lock);
791 }
792 spin_unlock_irq(lock);
793
794 /*
795 * At this point all other threads have exited, all we have to
796 * do is to wait for the thread group leader to become inactive,
797 * and to assume its PID:
798 */
799 if (!thread_group_leader(tsk)) {
800 leader = tsk->group_leader;
801
802 sig->notify_count = -1; /* for exit_notify() */
803 for (;;) {
804 write_lock_irq(&tasklist_lock);
805 if (likely(leader->exit_state))
806 break;
807 __set_current_state(TASK_UNINTERRUPTIBLE);
808 write_unlock_irq(&tasklist_lock);
809 schedule();
810 }
811
812 if (unlikely(task_child_reaper(tsk) == leader))
813 task_active_pid_ns(tsk)->child_reaper = tsk;
814 /*
815 * The only record we have of the real-time age of a
816 * process, regardless of execs it's done, is start_time.
817 * All the past CPU time is accumulated in signal_struct
818 * from sister threads now dead. But in this non-leader
819 * exec, nothing survives from the original leader thread,
820 * whose birth marks the true age of this process now.
821 * When we take on its identity by switching to its PID, we
822 * also take its birthdate (always earlier than our own).
823 */
824 tsk->start_time = leader->start_time;
825
826 BUG_ON(!same_thread_group(leader, tsk));
827 BUG_ON(has_group_leader_pid(tsk));
828 /*
829 * An exec() starts a new thread group with the
830 * TGID of the previous thread group. Rehash the
831 * two threads with a switched PID, and release
832 * the former thread group leader:
833 */
834
835 /* Become a process group leader with the old leader's pid.
836 * The old leader becomes a thread of the this thread group.
837 * Note: The old leader also uses this pid until release_task
838 * is called. Odd but simple and correct.
839 */
840 detach_pid(tsk, PIDTYPE_PID);
841 tsk->pid = leader->pid;
842 attach_pid(tsk, PIDTYPE_PID, task_pid(leader));
843 transfer_pid(leader, tsk, PIDTYPE_PGID);
844 transfer_pid(leader, tsk, PIDTYPE_SID);
845 list_replace_rcu(&leader->tasks, &tsk->tasks);
846
847 tsk->group_leader = tsk;
848 leader->group_leader = tsk;
849
850 tsk->exit_signal = SIGCHLD;
851
852 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
853 leader->exit_state = EXIT_DEAD;
854
855 write_unlock_irq(&tasklist_lock);
856 }
857
858 sig->group_exit_task = NULL;
859 sig->notify_count = 0;
860
861 no_thread_group:
862 exit_itimers(sig);
863 if (leader)
864 release_task(leader);
865
866 if (atomic_read(&oldsighand->count) != 1) {
867 struct sighand_struct *newsighand;
868 /*
869 * This ->sighand is shared with the CLONE_SIGHAND
870 * but not CLONE_THREAD task, switch to the new one.
871 */
872 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
873 if (!newsighand)
874 return -ENOMEM;
875
876 atomic_set(&newsighand->count, 1);
877 memcpy(newsighand->action, oldsighand->action,
878 sizeof(newsighand->action));
879
880 write_lock_irq(&tasklist_lock);
881 spin_lock(&oldsighand->siglock);
882 rcu_assign_pointer(tsk->sighand, newsighand);
883 spin_unlock(&oldsighand->siglock);
884 write_unlock_irq(&tasklist_lock);
885
886 __cleanup_sighand(oldsighand);
887 }
888
889 BUG_ON(!thread_group_leader(tsk));
890 return 0;
891 }
892
893 /*
894 * These functions flushes out all traces of the currently running executable
895 * so that a new one can be started
896 */
897 static void flush_old_files(struct files_struct * files)
898 {
899 long j = -1;
900 struct fdtable *fdt;
901
902 spin_lock(&files->file_lock);
903 for (;;) {
904 unsigned long set, i;
905
906 j++;
907 i = j * __NFDBITS;
908 fdt = files_fdtable(files);
909 if (i >= fdt->max_fds)
910 break;
911 set = fdt->close_on_exec->fds_bits[j];
912 if (!set)
913 continue;
914 fdt->close_on_exec->fds_bits[j] = 0;
915 spin_unlock(&files->file_lock);
916 for ( ; set ; i++,set >>= 1) {
917 if (set & 1) {
918 sys_close(i);
919 }
920 }
921 spin_lock(&files->file_lock);
922
923 }
924 spin_unlock(&files->file_lock);
925 }
926
927 char *get_task_comm(char *buf, struct task_struct *tsk)
928 {
929 /* buf must be at least sizeof(tsk->comm) in size */
930 task_lock(tsk);
931 strncpy(buf, tsk->comm, sizeof(tsk->comm));
932 task_unlock(tsk);
933 return buf;
934 }
935
936 void set_task_comm(struct task_struct *tsk, char *buf)
937 {
938 task_lock(tsk);
939 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
940 task_unlock(tsk);
941 }
942
943 int flush_old_exec(struct linux_binprm * bprm)
944 {
945 char * name;
946 int i, ch, retval;
947 char tcomm[sizeof(current->comm)];
948
949 /*
950 * Make sure we have a private signal table and that
951 * we are unassociated from the previous thread group.
952 */
953 retval = de_thread(current);
954 if (retval)
955 goto out;
956
957 set_mm_exe_file(bprm->mm, bprm->file);
958
959 /*
960 * Release all of the old mmap stuff
961 */
962 retval = exec_mmap(bprm->mm);
963 if (retval)
964 goto out;
965
966 bprm->mm = NULL; /* We're using it now */
967
968 /* This is the point of no return */
969 current->sas_ss_sp = current->sas_ss_size = 0;
970
971 if (current->euid == current->uid && current->egid == current->gid)
972 set_dumpable(current->mm, 1);
973 else
974 set_dumpable(current->mm, suid_dumpable);
975
976 name = bprm->filename;
977
978 /* Copies the binary name from after last slash */
979 for (i=0; (ch = *(name++)) != '\0';) {
980 if (ch == '/')
981 i = 0; /* overwrite what we wrote */
982 else
983 if (i < (sizeof(tcomm) - 1))
984 tcomm[i++] = ch;
985 }
986 tcomm[i] = '\0';
987 set_task_comm(current, tcomm);
988
989 current->flags &= ~PF_RANDOMIZE;
990 flush_thread();
991
992 /* Set the new mm task size. We have to do that late because it may
993 * depend on TIF_32BIT which is only updated in flush_thread() on
994 * some architectures like powerpc
995 */
996 current->mm->task_size = TASK_SIZE;
997
998 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
999 suid_keys(current);
1000 set_dumpable(current->mm, suid_dumpable);
1001 current->pdeath_signal = 0;
1002 } else if (file_permission(bprm->file, MAY_READ) ||
1003 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
1004 suid_keys(current);
1005 set_dumpable(current->mm, suid_dumpable);
1006 }
1007
1008 /* An exec changes our domain. We are no longer part of the thread
1009 group */
1010
1011 current->self_exec_id++;
1012
1013 flush_signal_handlers(current, 0);
1014 flush_old_files(current->files);
1015
1016 return 0;
1017
1018 out:
1019 return retval;
1020 }
1021
1022 EXPORT_SYMBOL(flush_old_exec);
1023
1024 /*
1025 * Fill the binprm structure from the inode.
1026 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
1027 */
1028 int prepare_binprm(struct linux_binprm *bprm)
1029 {
1030 int mode;
1031 struct inode * inode = bprm->file->f_path.dentry->d_inode;
1032 int retval;
1033
1034 mode = inode->i_mode;
1035 if (bprm->file->f_op == NULL)
1036 return -EACCES;
1037
1038 bprm->e_uid = current->euid;
1039 bprm->e_gid = current->egid;
1040
1041 if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
1042 /* Set-uid? */
1043 if (mode & S_ISUID) {
1044 current->personality &= ~PER_CLEAR_ON_SETID;
1045 bprm->e_uid = inode->i_uid;
1046 }
1047
1048 /* Set-gid? */
1049 /*
1050 * If setgid is set but no group execute bit then this
1051 * is a candidate for mandatory locking, not a setgid
1052 * executable.
1053 */
1054 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1055 current->personality &= ~PER_CLEAR_ON_SETID;
1056 bprm->e_gid = inode->i_gid;
1057 }
1058 }
1059
1060 /* fill in binprm security blob */
1061 retval = security_bprm_set(bprm);
1062 if (retval)
1063 return retval;
1064
1065 memset(bprm->buf,0,BINPRM_BUF_SIZE);
1066 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
1067 }
1068
1069 EXPORT_SYMBOL(prepare_binprm);
1070
1071 static int unsafe_exec(struct task_struct *p)
1072 {
1073 int unsafe = 0;
1074 if (p->ptrace & PT_PTRACED) {
1075 if (p->ptrace & PT_PTRACE_CAP)
1076 unsafe |= LSM_UNSAFE_PTRACE_CAP;
1077 else
1078 unsafe |= LSM_UNSAFE_PTRACE;
1079 }
1080 if (atomic_read(&p->fs->count) > 1 ||
1081 atomic_read(&p->files->count) > 1 ||
1082 atomic_read(&p->sighand->count) > 1)
1083 unsafe |= LSM_UNSAFE_SHARE;
1084
1085 return unsafe;
1086 }
1087
1088 void compute_creds(struct linux_binprm *bprm)
1089 {
1090 int unsafe;
1091
1092 if (bprm->e_uid != current->uid) {
1093 suid_keys(current);
1094 current->pdeath_signal = 0;
1095 }
1096 exec_keys(current);
1097
1098 task_lock(current);
1099 unsafe = unsafe_exec(current);
1100 security_bprm_apply_creds(bprm, unsafe);
1101 task_unlock(current);
1102 security_bprm_post_apply_creds(bprm);
1103 }
1104 EXPORT_SYMBOL(compute_creds);
1105
1106 /*
1107 * Arguments are '\0' separated strings found at the location bprm->p
1108 * points to; chop off the first by relocating brpm->p to right after
1109 * the first '\0' encountered.
1110 */
1111 int remove_arg_zero(struct linux_binprm *bprm)
1112 {
1113 int ret = 0;
1114 unsigned long offset;
1115 char *kaddr;
1116 struct page *page;
1117
1118 if (!bprm->argc)
1119 return 0;
1120
1121 do {
1122 offset = bprm->p & ~PAGE_MASK;
1123 page = get_arg_page(bprm, bprm->p, 0);
1124 if (!page) {
1125 ret = -EFAULT;
1126 goto out;
1127 }
1128 kaddr = kmap_atomic(page, KM_USER0);
1129
1130 for (; offset < PAGE_SIZE && kaddr[offset];
1131 offset++, bprm->p++)
1132 ;
1133
1134 kunmap_atomic(kaddr, KM_USER0);
1135 put_arg_page(page);
1136
1137 if (offset == PAGE_SIZE)
1138 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
1139 } while (offset == PAGE_SIZE);
1140
1141 bprm->p++;
1142 bprm->argc--;
1143 ret = 0;
1144
1145 out:
1146 return ret;
1147 }
1148 EXPORT_SYMBOL(remove_arg_zero);
1149
1150 /*
1151 * cycle the list of binary formats handler, until one recognizes the image
1152 */
1153 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1154 {
1155 int try,retval;
1156 struct linux_binfmt *fmt;
1157 #if defined(__alpha__) && defined(CONFIG_ARCH_SUPPORTS_AOUT)
1158 /* handle /sbin/loader.. */
1159 {
1160 struct exec * eh = (struct exec *) bprm->buf;
1161
1162 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1163 (eh->fh.f_flags & 0x3000) == 0x3000)
1164 {
1165 struct file * file;
1166 unsigned long loader;
1167
1168 allow_write_access(bprm->file);
1169 fput(bprm->file);
1170 bprm->file = NULL;
1171
1172 loader = bprm->vma->vm_end - sizeof(void *);
1173
1174 file = open_exec("/sbin/loader");
1175 retval = PTR_ERR(file);
1176 if (IS_ERR(file))
1177 return retval;
1178
1179 /* Remember if the application is TASO. */
1180 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1181
1182 bprm->file = file;
1183 bprm->loader = loader;
1184 retval = prepare_binprm(bprm);
1185 if (retval<0)
1186 return retval;
1187 /* should call search_binary_handler recursively here,
1188 but it does not matter */
1189 }
1190 }
1191 #endif
1192 retval = security_bprm_check(bprm);
1193 if (retval)
1194 return retval;
1195
1196 /* kernel module loader fixup */
1197 /* so we don't try to load run modprobe in kernel space. */
1198 set_fs(USER_DS);
1199
1200 retval = audit_bprm(bprm);
1201 if (retval)
1202 return retval;
1203
1204 retval = -ENOENT;
1205 for (try=0; try<2; try++) {
1206 read_lock(&binfmt_lock);
1207 list_for_each_entry(fmt, &formats, lh) {
1208 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1209 if (!fn)
1210 continue;
1211 if (!try_module_get(fmt->module))
1212 continue;
1213 read_unlock(&binfmt_lock);
1214 retval = fn(bprm, regs);
1215 if (retval >= 0) {
1216 put_binfmt(fmt);
1217 allow_write_access(bprm->file);
1218 if (bprm->file)
1219 fput(bprm->file);
1220 bprm->file = NULL;
1221 current->did_exec = 1;
1222 proc_exec_connector(current);
1223 return retval;
1224 }
1225 read_lock(&binfmt_lock);
1226 put_binfmt(fmt);
1227 if (retval != -ENOEXEC || bprm->mm == NULL)
1228 break;
1229 if (!bprm->file) {
1230 read_unlock(&binfmt_lock);
1231 return retval;
1232 }
1233 }
1234 read_unlock(&binfmt_lock);
1235 if (retval != -ENOEXEC || bprm->mm == NULL) {
1236 break;
1237 #ifdef CONFIG_KMOD
1238 }else{
1239 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1240 if (printable(bprm->buf[0]) &&
1241 printable(bprm->buf[1]) &&
1242 printable(bprm->buf[2]) &&
1243 printable(bprm->buf[3]))
1244 break; /* -ENOEXEC */
1245 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1246 #endif
1247 }
1248 }
1249 return retval;
1250 }
1251
1252 EXPORT_SYMBOL(search_binary_handler);
1253
1254 /*
1255 * sys_execve() executes a new program.
1256 */
1257 int do_execve(char * filename,
1258 char __user *__user *argv,
1259 char __user *__user *envp,
1260 struct pt_regs * regs)
1261 {
1262 struct linux_binprm *bprm;
1263 struct file *file;
1264 struct files_struct *displaced;
1265 int retval;
1266
1267 retval = unshare_files(&displaced);
1268 if (retval)
1269 goto out_ret;
1270
1271 retval = -ENOMEM;
1272 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1273 if (!bprm)
1274 goto out_files;
1275
1276 file = open_exec(filename);
1277 retval = PTR_ERR(file);
1278 if (IS_ERR(file))
1279 goto out_kfree;
1280
1281 sched_exec();
1282
1283 bprm->file = file;
1284 bprm->filename = filename;
1285 bprm->interp = filename;
1286
1287 retval = bprm_mm_init(bprm);
1288 if (retval)
1289 goto out_file;
1290
1291 bprm->argc = count(argv, MAX_ARG_STRINGS);
1292 if ((retval = bprm->argc) < 0)
1293 goto out_mm;
1294
1295 bprm->envc = count(envp, MAX_ARG_STRINGS);
1296 if ((retval = bprm->envc) < 0)
1297 goto out_mm;
1298
1299 retval = security_bprm_alloc(bprm);
1300 if (retval)
1301 goto out;
1302
1303 retval = prepare_binprm(bprm);
1304 if (retval < 0)
1305 goto out;
1306
1307 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1308 if (retval < 0)
1309 goto out;
1310
1311 bprm->exec = bprm->p;
1312 retval = copy_strings(bprm->envc, envp, bprm);
1313 if (retval < 0)
1314 goto out;
1315
1316 retval = copy_strings(bprm->argc, argv, bprm);
1317 if (retval < 0)
1318 goto out;
1319
1320 retval = search_binary_handler(bprm,regs);
1321 if (retval >= 0) {
1322 /* execve success */
1323 free_arg_pages(bprm);
1324 security_bprm_free(bprm);
1325 acct_update_integrals(current);
1326 kfree(bprm);
1327 if (displaced)
1328 put_files_struct(displaced);
1329 return retval;
1330 }
1331
1332 out:
1333 free_arg_pages(bprm);
1334 if (bprm->security)
1335 security_bprm_free(bprm);
1336
1337 out_mm:
1338 if (bprm->mm)
1339 mmput (bprm->mm);
1340
1341 out_file:
1342 if (bprm->file) {
1343 allow_write_access(bprm->file);
1344 fput(bprm->file);
1345 }
1346 out_kfree:
1347 kfree(bprm);
1348
1349 out_files:
1350 if (displaced)
1351 reset_files_struct(displaced);
1352 out_ret:
1353 return retval;
1354 }
1355
1356 int set_binfmt(struct linux_binfmt *new)
1357 {
1358 struct linux_binfmt *old = current->binfmt;
1359
1360 if (new) {
1361 if (!try_module_get(new->module))
1362 return -1;
1363 }
1364 current->binfmt = new;
1365 if (old)
1366 module_put(old->module);
1367 return 0;
1368 }
1369
1370 EXPORT_SYMBOL(set_binfmt);
1371
1372 /* format_corename will inspect the pattern parameter, and output a
1373 * name into corename, which must have space for at least
1374 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1375 */
1376 static int format_corename(char *corename, const char *pattern, long signr)
1377 {
1378 const char *pat_ptr = pattern;
1379 char *out_ptr = corename;
1380 char *const out_end = corename + CORENAME_MAX_SIZE;
1381 int rc;
1382 int pid_in_pattern = 0;
1383 int ispipe = 0;
1384
1385 if (*pattern == '|')
1386 ispipe = 1;
1387
1388 /* Repeat as long as we have more pattern to process and more output
1389 space */
1390 while (*pat_ptr) {
1391 if (*pat_ptr != '%') {
1392 if (out_ptr == out_end)
1393 goto out;
1394 *out_ptr++ = *pat_ptr++;
1395 } else {
1396 switch (*++pat_ptr) {
1397 case 0:
1398 goto out;
1399 /* Double percent, output one percent */
1400 case '%':
1401 if (out_ptr == out_end)
1402 goto out;
1403 *out_ptr++ = '%';
1404 break;
1405 /* pid */
1406 case 'p':
1407 pid_in_pattern = 1;
1408 rc = snprintf(out_ptr, out_end - out_ptr,
1409 "%d", task_tgid_vnr(current));
1410 if (rc > out_end - out_ptr)
1411 goto out;
1412 out_ptr += rc;
1413 break;
1414 /* uid */
1415 case 'u':
1416 rc = snprintf(out_ptr, out_end - out_ptr,
1417 "%d", current->uid);
1418 if (rc > out_end - out_ptr)
1419 goto out;
1420 out_ptr += rc;
1421 break;
1422 /* gid */
1423 case 'g':
1424 rc = snprintf(out_ptr, out_end - out_ptr,
1425 "%d", current->gid);
1426 if (rc > out_end - out_ptr)
1427 goto out;
1428 out_ptr += rc;
1429 break;
1430 /* signal that caused the coredump */
1431 case 's':
1432 rc = snprintf(out_ptr, out_end - out_ptr,
1433 "%ld", signr);
1434 if (rc > out_end - out_ptr)
1435 goto out;
1436 out_ptr += rc;
1437 break;
1438 /* UNIX time of coredump */
1439 case 't': {
1440 struct timeval tv;
1441 do_gettimeofday(&tv);
1442 rc = snprintf(out_ptr, out_end - out_ptr,
1443 "%lu", tv.tv_sec);
1444 if (rc > out_end - out_ptr)
1445 goto out;
1446 out_ptr += rc;
1447 break;
1448 }
1449 /* hostname */
1450 case 'h':
1451 down_read(&uts_sem);
1452 rc = snprintf(out_ptr, out_end - out_ptr,
1453 "%s", utsname()->nodename);
1454 up_read(&uts_sem);
1455 if (rc > out_end - out_ptr)
1456 goto out;
1457 out_ptr += rc;
1458 break;
1459 /* executable */
1460 case 'e':
1461 rc = snprintf(out_ptr, out_end - out_ptr,
1462 "%s", current->comm);
1463 if (rc > out_end - out_ptr)
1464 goto out;
1465 out_ptr += rc;
1466 break;
1467 /* core limit size */
1468 case 'c':
1469 rc = snprintf(out_ptr, out_end - out_ptr,
1470 "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
1471 if (rc > out_end - out_ptr)
1472 goto out;
1473 out_ptr += rc;
1474 break;
1475 default:
1476 break;
1477 }
1478 ++pat_ptr;
1479 }
1480 }
1481 /* Backward compatibility with core_uses_pid:
1482 *
1483 * If core_pattern does not include a %p (as is the default)
1484 * and core_uses_pid is set, then .%pid will be appended to
1485 * the filename. Do not do this for piped commands. */
1486 if (!ispipe && !pid_in_pattern
1487 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1488 rc = snprintf(out_ptr, out_end - out_ptr,
1489 ".%d", task_tgid_vnr(current));
1490 if (rc > out_end - out_ptr)
1491 goto out;
1492 out_ptr += rc;
1493 }
1494 out:
1495 *out_ptr = 0;
1496 return ispipe;
1497 }
1498
1499 static void zap_process(struct task_struct *start)
1500 {
1501 struct task_struct *t;
1502
1503 start->signal->flags = SIGNAL_GROUP_EXIT;
1504 start->signal->group_stop_count = 0;
1505
1506 t = start;
1507 do {
1508 if (t != current && t->mm) {
1509 t->mm->core_waiters++;
1510 sigaddset(&t->pending.signal, SIGKILL);
1511 signal_wake_up(t, 1);
1512 }
1513 } while ((t = next_thread(t)) != start);
1514 }
1515
1516 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1517 int exit_code)
1518 {
1519 struct task_struct *g, *p;
1520 unsigned long flags;
1521 int err = -EAGAIN;
1522
1523 spin_lock_irq(&tsk->sighand->siglock);
1524 if (!signal_group_exit(tsk->signal)) {
1525 tsk->signal->group_exit_code = exit_code;
1526 zap_process(tsk);
1527 err = 0;
1528 }
1529 spin_unlock_irq(&tsk->sighand->siglock);
1530 if (err)
1531 return err;
1532
1533 if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1534 goto done;
1535
1536 rcu_read_lock();
1537 for_each_process(g) {
1538 if (g == tsk->group_leader)
1539 continue;
1540
1541 p = g;
1542 do {
1543 if (p->mm) {
1544 if (p->mm == mm) {
1545 /*
1546 * p->sighand can't disappear, but
1547 * may be changed by de_thread()
1548 */
1549 lock_task_sighand(p, &flags);
1550 zap_process(p);
1551 unlock_task_sighand(p, &flags);
1552 }
1553 break;
1554 }
1555 } while ((p = next_thread(p)) != g);
1556 }
1557 rcu_read_unlock();
1558 done:
1559 return mm->core_waiters;
1560 }
1561
1562 static int coredump_wait(int exit_code)
1563 {
1564 struct task_struct *tsk = current;
1565 struct mm_struct *mm = tsk->mm;
1566 struct completion startup_done;
1567 struct completion *vfork_done;
1568 int core_waiters;
1569
1570 init_completion(&mm->core_done);
1571 init_completion(&startup_done);
1572 mm->core_startup_done = &startup_done;
1573
1574 core_waiters = zap_threads(tsk, mm, exit_code);
1575 up_write(&mm->mmap_sem);
1576
1577 if (unlikely(core_waiters < 0))
1578 goto fail;
1579
1580 /*
1581 * Make sure nobody is waiting for us to release the VM,
1582 * otherwise we can deadlock when we wait on each other
1583 */
1584 vfork_done = tsk->vfork_done;
1585 if (vfork_done) {
1586 tsk->vfork_done = NULL;
1587 complete(vfork_done);
1588 }
1589
1590 if (core_waiters)
1591 wait_for_completion(&startup_done);
1592 fail:
1593 BUG_ON(mm->core_waiters);
1594 return core_waiters;
1595 }
1596
1597 /*
1598 * set_dumpable converts traditional three-value dumpable to two flags and
1599 * stores them into mm->flags. It modifies lower two bits of mm->flags, but
1600 * these bits are not changed atomically. So get_dumpable can observe the
1601 * intermediate state. To avoid doing unexpected behavior, get get_dumpable
1602 * return either old dumpable or new one by paying attention to the order of
1603 * modifying the bits.
1604 *
1605 * dumpable | mm->flags (binary)
1606 * old new | initial interim final
1607 * ---------+-----------------------
1608 * 0 1 | 00 01 01
1609 * 0 2 | 00 10(*) 11
1610 * 1 0 | 01 00 00
1611 * 1 2 | 01 11 11
1612 * 2 0 | 11 10(*) 00
1613 * 2 1 | 11 11 01
1614 *
1615 * (*) get_dumpable regards interim value of 10 as 11.
1616 */
1617 void set_dumpable(struct mm_struct *mm, int value)
1618 {
1619 switch (value) {
1620 case 0:
1621 clear_bit(MMF_DUMPABLE, &mm->flags);
1622 smp_wmb();
1623 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1624 break;
1625 case 1:
1626 set_bit(MMF_DUMPABLE, &mm->flags);
1627 smp_wmb();
1628 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1629 break;
1630 case 2:
1631 set_bit(MMF_DUMP_SECURELY, &mm->flags);
1632 smp_wmb();
1633 set_bit(MMF_DUMPABLE, &mm->flags);
1634 break;
1635 }
1636 }
1637
1638 int get_dumpable(struct mm_struct *mm)
1639 {
1640 int ret;
1641
1642 ret = mm->flags & 0x3;
1643 return (ret >= 2) ? 2 : ret;
1644 }
1645
1646 int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1647 {
1648 char corename[CORENAME_MAX_SIZE + 1];
1649 struct mm_struct *mm = current->mm;
1650 struct linux_binfmt * binfmt;
1651 struct inode * inode;
1652 struct file * file;
1653 int retval = 0;
1654 int fsuid = current->fsuid;
1655 int flag = 0;
1656 int ispipe = 0;
1657 unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
1658 char **helper_argv = NULL;
1659 int helper_argc = 0;
1660 char *delimit;
1661
1662 audit_core_dumps(signr);
1663
1664 binfmt = current->binfmt;
1665 if (!binfmt || !binfmt->core_dump)
1666 goto fail;
1667 down_write(&mm->mmap_sem);
1668 /*
1669 * If another thread got here first, or we are not dumpable, bail out.
1670 */
1671 if (mm->core_waiters || !get_dumpable(mm)) {
1672 up_write(&mm->mmap_sem);
1673 goto fail;
1674 }
1675
1676 /*
1677 * We cannot trust fsuid as being the "true" uid of the
1678 * process nor do we know its entire history. We only know it
1679 * was tainted so we dump it as root in mode 2.
1680 */
1681 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
1682 flag = O_EXCL; /* Stop rewrite attacks */
1683 current->fsuid = 0; /* Dump root private */
1684 }
1685
1686 retval = coredump_wait(exit_code);
1687 if (retval < 0)
1688 goto fail;
1689
1690 /*
1691 * Clear any false indication of pending signals that might
1692 * be seen by the filesystem code called to write the core file.
1693 */
1694 clear_thread_flag(TIF_SIGPENDING);
1695
1696 /*
1697 * lock_kernel() because format_corename() is controlled by sysctl, which
1698 * uses lock_kernel()
1699 */
1700 lock_kernel();
1701 ispipe = format_corename(corename, core_pattern, signr);
1702 unlock_kernel();
1703 /*
1704 * Don't bother to check the RLIMIT_CORE value if core_pattern points
1705 * to a pipe. Since we're not writing directly to the filesystem
1706 * RLIMIT_CORE doesn't really apply, as no actual core file will be
1707 * created unless the pipe reader choses to write out the core file
1708 * at which point file size limits and permissions will be imposed
1709 * as it does with any other process
1710 */
1711 if ((!ispipe) && (core_limit < binfmt->min_coredump))
1712 goto fail_unlock;
1713
1714 if (ispipe) {
1715 helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
1716 /* Terminate the string before the first option */
1717 delimit = strchr(corename, ' ');
1718 if (delimit)
1719 *delimit = '\0';
1720 delimit = strrchr(helper_argv[0], '/');
1721 if (delimit)
1722 delimit++;
1723 else
1724 delimit = helper_argv[0];
1725 if (!strcmp(delimit, current->comm)) {
1726 printk(KERN_NOTICE "Recursive core dump detected, "
1727 "aborting\n");
1728 goto fail_unlock;
1729 }
1730
1731 core_limit = RLIM_INFINITY;
1732
1733 /* SIGPIPE can happen, but it's just never processed */
1734 if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
1735 &file)) {
1736 printk(KERN_INFO "Core dump to %s pipe failed\n",
1737 corename);
1738 goto fail_unlock;
1739 }
1740 } else
1741 file = filp_open(corename,
1742 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1743 0600);
1744 if (IS_ERR(file))
1745 goto fail_unlock;
1746 inode = file->f_path.dentry->d_inode;
1747 if (inode->i_nlink > 1)
1748 goto close_fail; /* multiple links - don't dump */
1749 if (!ispipe && d_unhashed(file->f_path.dentry))
1750 goto close_fail;
1751
1752 /* AK: actually i see no reason to not allow this for named pipes etc.,
1753 but keep the previous behaviour for now. */
1754 if (!ispipe && !S_ISREG(inode->i_mode))
1755 goto close_fail;
1756 /*
1757 * Dont allow local users get cute and trick others to coredump
1758 * into their pre-created files:
1759 */
1760 if (inode->i_uid != current->fsuid)
1761 goto close_fail;
1762 if (!file->f_op)
1763 goto close_fail;
1764 if (!file->f_op->write)
1765 goto close_fail;
1766 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
1767 goto close_fail;
1768
1769 retval = binfmt->core_dump(signr, regs, file, core_limit);
1770
1771 if (retval)
1772 current->signal->group_exit_code |= 0x80;
1773 close_fail:
1774 filp_close(file, NULL);
1775 fail_unlock:
1776 if (helper_argv)
1777 argv_free(helper_argv);
1778
1779 current->fsuid = fsuid;
1780 complete_all(&mm->core_done);
1781 fail:
1782 return retval;
1783 }
kernel source for telekom puls (alcatel/mediatek)