blob: 1ba85c7fc6af7e4290ac494563f3fc6c8d8587bd [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>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080041#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#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>
Jay Lan8f0ab512006-09-30 23:28:59 -070050#include <linux/tsacct_kern.h>
Matt Helsley9f460802005-11-07 00:59:16 -080051#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040052#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54#include <asm/uaccess.h>
55#include <asm/mmu_context.h>
56
57#ifdef CONFIG_KMOD
58#include <linux/kmod.h>
59#endif
60
61int core_uses_pid;
Andi Kleend025c9d2006-09-30 23:29:28 -070062char core_pattern[128] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070063int suid_dumpable = 0;
64
65EXPORT_SYMBOL(suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066/* The maximal length of core_pattern is also specified in sysctl.c */
67
68static struct linux_binfmt *formats;
69static DEFINE_RWLOCK(binfmt_lock);
70
71int register_binfmt(struct linux_binfmt * fmt)
72{
73 struct linux_binfmt ** tmp = &formats;
74
75 if (!fmt)
76 return -EINVAL;
77 if (fmt->next)
78 return -EBUSY;
79 write_lock(&binfmt_lock);
80 while (*tmp) {
81 if (fmt == *tmp) {
82 write_unlock(&binfmt_lock);
83 return -EBUSY;
84 }
85 tmp = &(*tmp)->next;
86 }
87 fmt->next = formats;
88 formats = fmt;
89 write_unlock(&binfmt_lock);
90 return 0;
91}
92
93EXPORT_SYMBOL(register_binfmt);
94
95int unregister_binfmt(struct linux_binfmt * fmt)
96{
97 struct linux_binfmt ** tmp = &formats;
98
99 write_lock(&binfmt_lock);
100 while (*tmp) {
101 if (fmt == *tmp) {
102 *tmp = fmt->next;
kalash nainwal98701d12007-05-08 00:28:31 -0700103 fmt->next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 write_unlock(&binfmt_lock);
105 return 0;
106 }
107 tmp = &(*tmp)->next;
108 }
109 write_unlock(&binfmt_lock);
110 return -EINVAL;
111}
112
113EXPORT_SYMBOL(unregister_binfmt);
114
115static inline void put_binfmt(struct linux_binfmt * fmt)
116{
117 module_put(fmt->module);
118}
119
120/*
121 * Note that a shared library must be both readable and executable due to
122 * security reasons.
123 *
124 * Also note that we take the address to load from from the file itself.
125 */
126asmlinkage long sys_uselib(const char __user * library)
127{
128 struct file * file;
129 struct nameidata nd;
130 int error;
131
Oleg Drokinb5005312006-03-25 03:07:01 -0800132 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 if (error)
134 goto out;
135
136 error = -EINVAL;
137 if (!S_ISREG(nd.dentry->d_inode->i_mode))
138 goto exit;
139
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800140 error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 if (error)
142 goto exit;
143
Trond Myklebust834f2a42005-10-18 14:20:16 -0700144 file = nameidata_to_filp(&nd, O_RDONLY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 error = PTR_ERR(file);
146 if (IS_ERR(file))
147 goto out;
148
149 error = -ENOEXEC;
150 if(file->f_op) {
151 struct linux_binfmt * fmt;
152
153 read_lock(&binfmt_lock);
154 for (fmt = formats ; fmt ; fmt = fmt->next) {
155 if (!fmt->load_shlib)
156 continue;
157 if (!try_module_get(fmt->module))
158 continue;
159 read_unlock(&binfmt_lock);
160 error = fmt->load_shlib(file);
161 read_lock(&binfmt_lock);
162 put_binfmt(fmt);
163 if (error != -ENOEXEC)
164 break;
165 }
166 read_unlock(&binfmt_lock);
167 }
168 fput(file);
169out:
170 return error;
171exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700172 release_open_intent(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 path_release(&nd);
174 goto out;
175}
176
177/*
178 * count() counts the number of strings in array ARGV.
179 */
180static int count(char __user * __user * argv, int max)
181{
182 int i = 0;
183
184 if (argv != NULL) {
185 for (;;) {
186 char __user * p;
187
188 if (get_user(p, argv))
189 return -EFAULT;
190 if (!p)
191 break;
192 argv++;
193 if(++i > max)
194 return -E2BIG;
195 cond_resched();
196 }
197 }
198 return i;
199}
200
201/*
202 * 'copy_strings()' copies argument/environment strings from user
203 * memory to free pages in kernel mem. These are in a format ready
204 * to be put directly into the top of new user memory.
205 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700206static int copy_strings(int argc, char __user * __user * argv,
207 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
209 struct page *kmapped_page = NULL;
210 char *kaddr = NULL;
211 int ret;
212
213 while (argc-- > 0) {
214 char __user *str;
215 int len;
216 unsigned long pos;
217
218 if (get_user(str, argv+argc) ||
219 !(len = strnlen_user(str, bprm->p))) {
220 ret = -EFAULT;
221 goto out;
222 }
223
224 if (bprm->p < len) {
225 ret = -E2BIG;
226 goto out;
227 }
228
229 bprm->p -= len;
230 /* XXX: add architecture specific overflow check here. */
231 pos = bprm->p;
232
233 while (len > 0) {
234 int i, new, err;
235 int offset, bytes_to_copy;
236 struct page *page;
237
238 offset = pos % PAGE_SIZE;
239 i = pos/PAGE_SIZE;
240 page = bprm->page[i];
241 new = 0;
242 if (!page) {
243 page = alloc_page(GFP_HIGHUSER);
244 bprm->page[i] = page;
245 if (!page) {
246 ret = -ENOMEM;
247 goto out;
248 }
249 new = 1;
250 }
251
252 if (page != kmapped_page) {
253 if (kmapped_page)
254 kunmap(kmapped_page);
255 kmapped_page = page;
256 kaddr = kmap(kmapped_page);
257 }
258 if (new && offset)
259 memset(kaddr, 0, offset);
260 bytes_to_copy = PAGE_SIZE - offset;
261 if (bytes_to_copy > len) {
262 bytes_to_copy = len;
263 if (new)
264 memset(kaddr+offset+len, 0,
265 PAGE_SIZE-offset-len);
266 }
267 err = copy_from_user(kaddr+offset, str, bytes_to_copy);
268 if (err) {
269 ret = -EFAULT;
270 goto out;
271 }
272
273 pos += bytes_to_copy;
274 str += bytes_to_copy;
275 len -= bytes_to_copy;
276 }
277 }
278 ret = 0;
279out:
280 if (kmapped_page)
281 kunmap(kmapped_page);
282 return ret;
283}
284
285/*
286 * Like copy_strings, but get argv and its values from kernel memory.
287 */
288int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
289{
290 int r;
291 mm_segment_t oldfs = get_fs();
292 set_fs(KERNEL_DS);
293 r = copy_strings(argc, (char __user * __user *)argv, bprm);
294 set_fs(oldfs);
295 return r;
296}
297
298EXPORT_SYMBOL(copy_strings_kernel);
299
300#ifdef CONFIG_MMU
301/*
302 * This routine is used to map in a page into an address space: needed by
303 * execve() for the initial stack and environment pages.
304 *
305 * vma->vm_mm->mmap_sem is held for writing.
306 */
307void install_arg_page(struct vm_area_struct *vma,
308 struct page *page, unsigned long address)
309{
310 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 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);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -0800318 pte = get_locked_pte(mm, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 if (!pte)
320 goto out;
321 if (!pte_none(*pte)) {
Hugh Dickinsc74df322005-10-29 18:16:23 -0700322 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 goto out;
324 }
Hugh Dickins42946212005-10-29 18:16:05 -0700325 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 lru_cache_add_active(page);
327 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
328 page, vma->vm_page_prot))));
Nick Piggin9617d952006-01-06 00:11:12 -0800329 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700330 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
332 /* no need for flush_tlb */
333 return;
334out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 __free_page(page);
336 force_sig(SIGKILL, current);
337}
338
339#define EXTRA_STACK_VM_PAGES 20 /* random */
340
341int setup_arg_pages(struct linux_binprm *bprm,
342 unsigned long stack_top,
343 int executable_stack)
344{
345 unsigned long stack_base;
346 struct vm_area_struct *mpnt;
347 struct mm_struct *mm = current->mm;
348 int i, ret;
349 long arg_size;
350
351#ifdef CONFIG_STACK_GROWSUP
352 /* Move the argument and environment strings to the bottom of the
353 * stack space.
354 */
355 int offset, j;
356 char *to, *from;
357
358 /* Start by shifting all the pages down */
359 i = 0;
360 for (j = 0; j < MAX_ARG_PAGES; j++) {
361 struct page *page = bprm->page[j];
362 if (!page)
363 continue;
364 bprm->page[i++] = page;
365 }
366
367 /* Now move them within their pages */
368 offset = bprm->p % PAGE_SIZE;
369 to = kmap(bprm->page[0]);
370 for (j = 1; j < i; j++) {
371 memmove(to, to + offset, PAGE_SIZE - offset);
372 from = kmap(bprm->page[j]);
373 memcpy(to + PAGE_SIZE - offset, from, offset);
374 kunmap(bprm->page[j - 1]);
375 to = from;
376 }
377 memmove(to, to + offset, PAGE_SIZE - offset);
378 kunmap(bprm->page[j - 1]);
379
380 /* Limit stack size to 1GB */
381 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
382 if (stack_base > (1 << 30))
383 stack_base = 1 << 30;
384 stack_base = PAGE_ALIGN(stack_top - stack_base);
385
386 /* Adjust bprm->p to point to the end of the strings. */
387 bprm->p = stack_base + PAGE_SIZE * i - offset;
388
389 mm->arg_start = stack_base;
390 arg_size = i << PAGE_SHIFT;
391
392 /* zero pages that were copied above */
393 while (i < MAX_ARG_PAGES)
394 bprm->page[i++] = NULL;
395#else
396 stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
397 stack_base = PAGE_ALIGN(stack_base);
398 bprm->p += stack_base;
399 mm->arg_start = bprm->p;
400 arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
401#endif
402
403 arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
404
405 if (bprm->loader)
406 bprm->loader += stack_base;
407 bprm->exec += stack_base;
408
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800409 mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 if (!mpnt)
411 return -ENOMEM;
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 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 */
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -0800623 if (unlikely(tsk->group_leader == child_reaper(tsk)))
624 tsk->nsproxy->pid_ns->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);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800785 if (i >= fdt->max_fds)
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;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800915 struct inode * inode = bprm->file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 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
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800925 if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 /* 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}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986EXPORT_SYMBOL(compute_creds);
987
Nick Piggin4fc75ff2007-05-08 00:25:16 -0700988/*
989 * Arguments are '\0' separated strings found at the location bprm->p
990 * points to; chop off the first by relocating brpm->p to right after
991 * the first '\0' encountered.
992 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993void remove_arg_zero(struct linux_binprm *bprm)
994{
995 if (bprm->argc) {
Nick Piggin4fc75ff2007-05-08 00:25:16 -0700996 char ch;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997
Nick Piggin4fc75ff2007-05-08 00:25:16 -0700998 do {
999 unsigned long offset;
1000 unsigned long index;
1001 char *kaddr;
1002 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001004 offset = bprm->p & ~PAGE_MASK;
1005 index = bprm->p >> PAGE_SHIFT;
1006
1007 page = bprm->page[index];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 kaddr = kmap_atomic(page, KM_USER0);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001009
1010 /* run through page until we reach end or find NUL */
1011 do {
1012 ch = *(kaddr + offset);
1013
1014 /* discard that character... */
1015 bprm->p++;
1016 offset++;
1017 } while (offset < PAGE_SIZE && ch != '\0');
1018
1019 kunmap_atomic(kaddr, KM_USER0);
1020
1021 /* free the old page */
1022 if (offset == PAGE_SIZE) {
1023 __free_page(page);
1024 bprm->page[index] = NULL;
1025 }
1026 } while (ch != '\0');
1027
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 bprm->argc--;
1029 }
1030}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031EXPORT_SYMBOL(remove_arg_zero);
1032
1033/*
1034 * cycle the list of binary formats handler, until one recognizes the image
1035 */
1036int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1037{
1038 int try,retval;
1039 struct linux_binfmt *fmt;
1040#ifdef __alpha__
1041 /* handle /sbin/loader.. */
1042 {
1043 struct exec * eh = (struct exec *) bprm->buf;
1044
1045 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1046 (eh->fh.f_flags & 0x3000) == 0x3000)
1047 {
1048 struct file * file;
1049 unsigned long loader;
1050
1051 allow_write_access(bprm->file);
1052 fput(bprm->file);
1053 bprm->file = NULL;
1054
1055 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1056
1057 file = open_exec("/sbin/loader");
1058 retval = PTR_ERR(file);
1059 if (IS_ERR(file))
1060 return retval;
1061
1062 /* Remember if the application is TASO. */
1063 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1064
1065 bprm->file = file;
1066 bprm->loader = loader;
1067 retval = prepare_binprm(bprm);
1068 if (retval<0)
1069 return retval;
1070 /* should call search_binary_handler recursively here,
1071 but it does not matter */
1072 }
1073 }
1074#endif
1075 retval = security_bprm_check(bprm);
1076 if (retval)
1077 return retval;
1078
1079 /* kernel module loader fixup */
1080 /* so we don't try to load run modprobe in kernel space. */
1081 set_fs(USER_DS);
Al Viro473ae302006-04-26 14:04:08 -04001082
1083 retval = audit_bprm(bprm);
1084 if (retval)
1085 return retval;
1086
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 retval = -ENOENT;
1088 for (try=0; try<2; try++) {
1089 read_lock(&binfmt_lock);
1090 for (fmt = formats ; fmt ; fmt = fmt->next) {
1091 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1092 if (!fn)
1093 continue;
1094 if (!try_module_get(fmt->module))
1095 continue;
1096 read_unlock(&binfmt_lock);
1097 retval = fn(bprm, regs);
1098 if (retval >= 0) {
1099 put_binfmt(fmt);
1100 allow_write_access(bprm->file);
1101 if (bprm->file)
1102 fput(bprm->file);
1103 bprm->file = NULL;
1104 current->did_exec = 1;
Matt Helsley9f460802005-11-07 00:59:16 -08001105 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 return retval;
1107 }
1108 read_lock(&binfmt_lock);
1109 put_binfmt(fmt);
1110 if (retval != -ENOEXEC || bprm->mm == NULL)
1111 break;
1112 if (!bprm->file) {
1113 read_unlock(&binfmt_lock);
1114 return retval;
1115 }
1116 }
1117 read_unlock(&binfmt_lock);
1118 if (retval != -ENOEXEC || bprm->mm == NULL) {
1119 break;
1120#ifdef CONFIG_KMOD
1121 }else{
1122#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1123 if (printable(bprm->buf[0]) &&
1124 printable(bprm->buf[1]) &&
1125 printable(bprm->buf[2]) &&
1126 printable(bprm->buf[3]))
1127 break; /* -ENOEXEC */
1128 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1129#endif
1130 }
1131 }
1132 return retval;
1133}
1134
1135EXPORT_SYMBOL(search_binary_handler);
1136
1137/*
1138 * sys_execve() executes a new program.
1139 */
1140int do_execve(char * filename,
1141 char __user *__user *argv,
1142 char __user *__user *envp,
1143 struct pt_regs * regs)
1144{
1145 struct linux_binprm *bprm;
1146 struct file *file;
1147 int retval;
1148 int i;
1149
1150 retval = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001151 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 if (!bprm)
1153 goto out_ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154
1155 file = open_exec(filename);
1156 retval = PTR_ERR(file);
1157 if (IS_ERR(file))
1158 goto out_kfree;
1159
1160 sched_exec();
1161
1162 bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1163
1164 bprm->file = file;
1165 bprm->filename = filename;
1166 bprm->interp = filename;
1167 bprm->mm = mm_alloc();
1168 retval = -ENOMEM;
1169 if (!bprm->mm)
1170 goto out_file;
1171
1172 retval = init_new_context(current, bprm->mm);
1173 if (retval < 0)
1174 goto out_mm;
1175
1176 bprm->argc = count(argv, bprm->p / sizeof(void *));
1177 if ((retval = bprm->argc) < 0)
1178 goto out_mm;
1179
1180 bprm->envc = count(envp, bprm->p / sizeof(void *));
1181 if ((retval = bprm->envc) < 0)
1182 goto out_mm;
1183
1184 retval = security_bprm_alloc(bprm);
1185 if (retval)
1186 goto out;
1187
1188 retval = prepare_binprm(bprm);
1189 if (retval < 0)
1190 goto out;
1191
1192 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1193 if (retval < 0)
1194 goto out;
1195
1196 bprm->exec = bprm->p;
1197 retval = copy_strings(bprm->envc, envp, bprm);
1198 if (retval < 0)
1199 goto out;
1200
1201 retval = copy_strings(bprm->argc, argv, bprm);
1202 if (retval < 0)
1203 goto out;
1204
1205 retval = search_binary_handler(bprm,regs);
1206 if (retval >= 0) {
1207 free_arg_pages(bprm);
1208
1209 /* execve success */
1210 security_bprm_free(bprm);
1211 acct_update_integrals(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 kfree(bprm);
1213 return retval;
1214 }
1215
1216out:
1217 /* Something went wrong, return the inode and free the argument pages*/
1218 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1219 struct page * page = bprm->page[i];
1220 if (page)
1221 __free_page(page);
1222 }
1223
1224 if (bprm->security)
1225 security_bprm_free(bprm);
1226
1227out_mm:
1228 if (bprm->mm)
1229 mmdrop(bprm->mm);
1230
1231out_file:
1232 if (bprm->file) {
1233 allow_write_access(bprm->file);
1234 fput(bprm->file);
1235 }
1236
1237out_kfree:
1238 kfree(bprm);
1239
1240out_ret:
1241 return retval;
1242}
1243
1244int set_binfmt(struct linux_binfmt *new)
1245{
1246 struct linux_binfmt *old = current->binfmt;
1247
1248 if (new) {
1249 if (!try_module_get(new->module))
1250 return -1;
1251 }
1252 current->binfmt = new;
1253 if (old)
1254 module_put(old->module);
1255 return 0;
1256}
1257
1258EXPORT_SYMBOL(set_binfmt);
1259
1260#define CORENAME_MAX_SIZE 64
1261
1262/* format_corename will inspect the pattern parameter, and output a
1263 * name into corename, which must have space for at least
1264 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1265 */
Alan Coxc4bbafd2007-04-16 22:53:13 -07001266static int format_corename(char *corename, const char *pattern, long signr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267{
1268 const char *pat_ptr = pattern;
1269 char *out_ptr = corename;
1270 char *const out_end = corename + CORENAME_MAX_SIZE;
1271 int rc;
1272 int pid_in_pattern = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001273 int ispipe = 0;
1274
1275 if (*pattern == '|')
1276 ispipe = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277
1278 /* Repeat as long as we have more pattern to process and more output
1279 space */
1280 while (*pat_ptr) {
1281 if (*pat_ptr != '%') {
1282 if (out_ptr == out_end)
1283 goto out;
1284 *out_ptr++ = *pat_ptr++;
1285 } else {
1286 switch (*++pat_ptr) {
1287 case 0:
1288 goto out;
1289 /* Double percent, output one percent */
1290 case '%':
1291 if (out_ptr == out_end)
1292 goto out;
1293 *out_ptr++ = '%';
1294 break;
1295 /* pid */
1296 case 'p':
1297 pid_in_pattern = 1;
1298 rc = snprintf(out_ptr, out_end - out_ptr,
1299 "%d", current->tgid);
1300 if (rc > out_end - out_ptr)
1301 goto out;
1302 out_ptr += rc;
1303 break;
1304 /* uid */
1305 case 'u':
1306 rc = snprintf(out_ptr, out_end - out_ptr,
1307 "%d", current->uid);
1308 if (rc > out_end - out_ptr)
1309 goto out;
1310 out_ptr += rc;
1311 break;
1312 /* gid */
1313 case 'g':
1314 rc = snprintf(out_ptr, out_end - out_ptr,
1315 "%d", current->gid);
1316 if (rc > out_end - out_ptr)
1317 goto out;
1318 out_ptr += rc;
1319 break;
1320 /* signal that caused the coredump */
1321 case 's':
1322 rc = snprintf(out_ptr, out_end - out_ptr,
1323 "%ld", signr);
1324 if (rc > out_end - out_ptr)
1325 goto out;
1326 out_ptr += rc;
1327 break;
1328 /* UNIX time of coredump */
1329 case 't': {
1330 struct timeval tv;
1331 do_gettimeofday(&tv);
1332 rc = snprintf(out_ptr, out_end - out_ptr,
1333 "%lu", tv.tv_sec);
1334 if (rc > out_end - out_ptr)
1335 goto out;
1336 out_ptr += rc;
1337 break;
1338 }
1339 /* hostname */
1340 case 'h':
1341 down_read(&uts_sem);
1342 rc = snprintf(out_ptr, out_end - out_ptr,
Serge E. Hallyne9ff3992006-10-02 02:18:11 -07001343 "%s", utsname()->nodename);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 up_read(&uts_sem);
1345 if (rc > out_end - out_ptr)
1346 goto out;
1347 out_ptr += rc;
1348 break;
1349 /* executable */
1350 case 'e':
1351 rc = snprintf(out_ptr, out_end - out_ptr,
1352 "%s", current->comm);
1353 if (rc > out_end - out_ptr)
1354 goto out;
1355 out_ptr += rc;
1356 break;
1357 default:
1358 break;
1359 }
1360 ++pat_ptr;
1361 }
1362 }
1363 /* Backward compatibility with core_uses_pid:
1364 *
1365 * If core_pattern does not include a %p (as is the default)
1366 * and core_uses_pid is set, then .%pid will be appended to
Alan Coxc4bbafd2007-04-16 22:53:13 -07001367 * the filename. Do not do this for piped commands. */
1368 if (!ispipe && !pid_in_pattern
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1370 rc = snprintf(out_ptr, out_end - out_ptr,
1371 ".%d", current->tgid);
1372 if (rc > out_end - out_ptr)
1373 goto out;
1374 out_ptr += rc;
1375 }
Alan Coxc4bbafd2007-04-16 22:53:13 -07001376out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 *out_ptr = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001378 return ispipe;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379}
1380
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001381static void zap_process(struct task_struct *start)
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001382{
1383 struct task_struct *t;
Oleg Nesterov281de332006-06-26 00:26:06 -07001384
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001385 start->signal->flags = SIGNAL_GROUP_EXIT;
1386 start->signal->group_stop_count = 0;
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001387
1388 t = start;
1389 do {
1390 if (t != current && t->mm) {
1391 t->mm->core_waiters++;
Oleg Nesterov281de332006-06-26 00:26:06 -07001392 sigaddset(&t->pending.signal, SIGKILL);
1393 signal_wake_up(t, 1);
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001394 }
1395 } while ((t = next_thread(t)) != start);
1396}
1397
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001398static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1399 int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400{
1401 struct task_struct *g, *p;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001402 unsigned long flags;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001403 int err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001405 spin_lock_irq(&tsk->sighand->siglock);
1406 if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001407 tsk->signal->group_exit_code = exit_code;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001408 zap_process(tsk);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001409 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 }
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001411 spin_unlock_irq(&tsk->sighand->siglock);
1412 if (err)
1413 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001415 if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1416 goto done;
1417
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001418 rcu_read_lock();
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001419 for_each_process(g) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001420 if (g == tsk->group_leader)
1421 continue;
1422
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001423 p = g;
1424 do {
1425 if (p->mm) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001426 if (p->mm == mm) {
1427 /*
1428 * p->sighand can't disappear, but
1429 * may be changed by de_thread()
1430 */
1431 lock_task_sighand(p, &flags);
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001432 zap_process(p);
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001433 unlock_task_sighand(p, &flags);
1434 }
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001435 break;
1436 }
1437 } while ((p = next_thread(p)) != g);
1438 }
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001439 rcu_read_unlock();
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001440done:
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001441 return mm->core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442}
1443
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001444static int coredump_wait(int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445{
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001446 struct task_struct *tsk = current;
1447 struct mm_struct *mm = tsk->mm;
1448 struct completion startup_done;
1449 struct completion *vfork_done;
Oleg Nesterov2384f552005-10-30 15:02:47 -08001450 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001452 init_completion(&mm->core_done);
1453 init_completion(&startup_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454 mm->core_startup_done = &startup_done;
1455
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001456 core_waiters = zap_threads(tsk, mm, exit_code);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001457 up_write(&mm->mmap_sem);
1458
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001459 if (unlikely(core_waiters < 0))
1460 goto fail;
1461
1462 /*
1463 * Make sure nobody is waiting for us to release the VM,
1464 * otherwise we can deadlock when we wait on each other
1465 */
1466 vfork_done = tsk->vfork_done;
1467 if (vfork_done) {
1468 tsk->vfork_done = NULL;
1469 complete(vfork_done);
1470 }
1471
Oleg Nesterov2384f552005-10-30 15:02:47 -08001472 if (core_waiters)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 wait_for_completion(&startup_done);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001474fail:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 BUG_ON(mm->core_waiters);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001476 return core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477}
1478
1479int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1480{
1481 char corename[CORENAME_MAX_SIZE + 1];
1482 struct mm_struct *mm = current->mm;
1483 struct linux_binfmt * binfmt;
1484 struct inode * inode;
1485 struct file * file;
1486 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001487 int fsuid = current->fsuid;
1488 int flag = 0;
Andi Kleend025c9d2006-09-30 23:29:28 -07001489 int ispipe = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490
1491 binfmt = current->binfmt;
1492 if (!binfmt || !binfmt->core_dump)
1493 goto fail;
1494 down_write(&mm->mmap_sem);
1495 if (!mm->dumpable) {
1496 up_write(&mm->mmap_sem);
1497 goto fail;
1498 }
Alan Coxd6e71142005-06-23 00:09:43 -07001499
1500 /*
1501 * We cannot trust fsuid as being the "true" uid of the
1502 * process nor do we know its entire history. We only know it
1503 * was tainted so we dump it as root in mode 2.
1504 */
1505 if (mm->dumpable == 2) { /* Setuid core dump mode */
1506 flag = O_EXCL; /* Stop rewrite attacks */
1507 current->fsuid = 0; /* Dump root private */
1508 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509 mm->dumpable = 0;
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001510
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001511 retval = coredump_wait(exit_code);
1512 if (retval < 0)
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001513 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514
1515 /*
1516 * Clear any false indication of pending signals that might
1517 * be seen by the filesystem code called to write the core file.
1518 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 clear_thread_flag(TIF_SIGPENDING);
1520
1521 if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1522 goto fail_unlock;
1523
1524 /*
1525 * lock_kernel() because format_corename() is controlled by sysctl, which
1526 * uses lock_kernel()
1527 */
1528 lock_kernel();
Alan Coxc4bbafd2007-04-16 22:53:13 -07001529 ispipe = format_corename(corename, core_pattern, signr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 unlock_kernel();
Alan Coxc4bbafd2007-04-16 22:53:13 -07001531 if (ispipe) {
Andi Kleend025c9d2006-09-30 23:29:28 -07001532 /* SIGPIPE can happen, but it's just never processed */
1533 if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
1534 printk(KERN_INFO "Core dump to %s pipe failed\n",
1535 corename);
1536 goto fail_unlock;
1537 }
Andi Kleend025c9d2006-09-30 23:29:28 -07001538 } else
1539 file = filp_open(corename,
Alexey Dobriyan6d4df672006-12-06 20:40:39 -08001540 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1541 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 if (IS_ERR(file))
1543 goto fail_unlock;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001544 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545 if (inode->i_nlink > 1)
1546 goto close_fail; /* multiple links - don't dump */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001547 if (!ispipe && d_unhashed(file->f_path.dentry))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548 goto close_fail;
1549
Andi Kleend025c9d2006-09-30 23:29:28 -07001550 /* AK: actually i see no reason to not allow this for named pipes etc.,
1551 but keep the previous behaviour for now. */
1552 if (!ispipe && !S_ISREG(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 goto close_fail;
1554 if (!file->f_op)
1555 goto close_fail;
1556 if (!file->f_op->write)
1557 goto close_fail;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001558 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559 goto close_fail;
1560
1561 retval = binfmt->core_dump(signr, regs, file);
1562
1563 if (retval)
1564 current->signal->group_exit_code |= 0x80;
1565close_fail:
1566 filp_close(file, NULL);
1567fail_unlock:
Alan Coxd6e71142005-06-23 00:09:43 -07001568 current->fsuid = fsuid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 complete_all(&mm->core_done);
1570fail:
1571 return retval;
1572}