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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/exec.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c1498
1 files changed, 1498 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c
new file mode 100644
index 000000000000..a8394499926c
--- /dev/null
+++ b/fs/exec.c
@@ -0,0 +1,1498 @@
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/config.h>
26#include <linux/slab.h>
27#include <linux/file.h>
28#include <linux/mman.h>
29#include <linux/a.out.h>
30#include <linux/stat.h>
31#include <linux/fcntl.h>
32#include <linux/smp_lock.h>
33#include <linux/init.h>
34#include <linux/pagemap.h>
35#include <linux/highmem.h>
36#include <linux/spinlock.h>
37#include <linux/key.h>
38#include <linux/personality.h>
39#include <linux/binfmts.h>
40#include <linux/swap.h>
41#include <linux/utsname.h>
42#include <linux/module.h>
43#include <linux/namei.h>
44#include <linux/proc_fs.h>
45#include <linux/ptrace.h>
46#include <linux/mount.h>
47#include <linux/security.h>
48#include <linux/syscalls.h>
49#include <linux/rmap.h>
50#include <linux/acct.h>
51
52#include <asm/uaccess.h>
53#include <asm/mmu_context.h>
54
55#ifdef CONFIG_KMOD
56#include <linux/kmod.h>
57#endif
58
59int core_uses_pid;
60char core_pattern[65] = "core";
61/* The maximal length of core_pattern is also specified in sysctl.c */
62
63static struct linux_binfmt *formats;
64static DEFINE_RWLOCK(binfmt_lock);
65
66int register_binfmt(struct linux_binfmt * fmt)
67{
68 struct linux_binfmt ** tmp = &formats;
69
70 if (!fmt)
71 return -EINVAL;
72 if (fmt->next)
73 return -EBUSY;
74 write_lock(&binfmt_lock);
75 while (*tmp) {
76 if (fmt == *tmp) {
77 write_unlock(&binfmt_lock);
78 return -EBUSY;
79 }
80 tmp = &(*tmp)->next;
81 }
82 fmt->next = formats;
83 formats = fmt;
84 write_unlock(&binfmt_lock);
85 return 0;
86}
87
88EXPORT_SYMBOL(register_binfmt);
89
90int unregister_binfmt(struct linux_binfmt * fmt)
91{
92 struct linux_binfmt ** tmp = &formats;
93
94 write_lock(&binfmt_lock);
95 while (*tmp) {
96 if (fmt == *tmp) {
97 *tmp = fmt->next;
98 write_unlock(&binfmt_lock);
99 return 0;
100 }
101 tmp = &(*tmp)->next;
102 }
103 write_unlock(&binfmt_lock);
104 return -EINVAL;
105}
106
107EXPORT_SYMBOL(unregister_binfmt);
108
109static inline void put_binfmt(struct linux_binfmt * fmt)
110{
111 module_put(fmt->module);
112}
113
114/*
115 * Note that a shared library must be both readable and executable due to
116 * security reasons.
117 *
118 * Also note that we take the address to load from from the file itself.
119 */
120asmlinkage long sys_uselib(const char __user * library)
121{
122 struct file * file;
123 struct nameidata nd;
124 int error;
125
126 nd.intent.open.flags = FMODE_READ;
127 error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
128 if (error)
129 goto out;
130
131 error = -EINVAL;
132 if (!S_ISREG(nd.dentry->d_inode->i_mode))
133 goto exit;
134
135 error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd);
136 if (error)
137 goto exit;
138
139 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
140 error = PTR_ERR(file);
141 if (IS_ERR(file))
142 goto out;
143
144 error = -ENOEXEC;
145 if(file->f_op) {
146 struct linux_binfmt * fmt;
147
148 read_lock(&binfmt_lock);
149 for (fmt = formats ; fmt ; fmt = fmt->next) {
150 if (!fmt->load_shlib)
151 continue;
152 if (!try_module_get(fmt->module))
153 continue;
154 read_unlock(&binfmt_lock);
155 error = fmt->load_shlib(file);
156 read_lock(&binfmt_lock);
157 put_binfmt(fmt);
158 if (error != -ENOEXEC)
159 break;
160 }
161 read_unlock(&binfmt_lock);
162 }
163 fput(file);
164out:
165 return error;
166exit:
167 path_release(&nd);
168 goto out;
169}
170
171/*
172 * count() counts the number of strings in array ARGV.
173 */
174static int count(char __user * __user * argv, int max)
175{
176 int i = 0;
177
178 if (argv != NULL) {
179 for (;;) {
180 char __user * p;
181
182 if (get_user(p, argv))
183 return -EFAULT;
184 if (!p)
185 break;
186 argv++;
187 if(++i > max)
188 return -E2BIG;
189 cond_resched();
190 }
191 }
192 return i;
193}
194
195/*
196 * 'copy_strings()' copies argument/environment strings from user
197 * memory to free pages in kernel mem. These are in a format ready
198 * to be put directly into the top of new user memory.
199 */
200int copy_strings(int argc,char __user * __user * argv, struct linux_binprm *bprm)
201{
202 struct page *kmapped_page = NULL;
203 char *kaddr = NULL;
204 int ret;
205
206 while (argc-- > 0) {
207 char __user *str;
208 int len;
209 unsigned long pos;
210
211 if (get_user(str, argv+argc) ||
212 !(len = strnlen_user(str, bprm->p))) {
213 ret = -EFAULT;
214 goto out;
215 }
216
217 if (bprm->p < len) {
218 ret = -E2BIG;
219 goto out;
220 }
221
222 bprm->p -= len;
223 /* XXX: add architecture specific overflow check here. */
224 pos = bprm->p;
225
226 while (len > 0) {
227 int i, new, err;
228 int offset, bytes_to_copy;
229 struct page *page;
230
231 offset = pos % PAGE_SIZE;
232 i = pos/PAGE_SIZE;
233 page = bprm->page[i];
234 new = 0;
235 if (!page) {
236 page = alloc_page(GFP_HIGHUSER);
237 bprm->page[i] = page;
238 if (!page) {
239 ret = -ENOMEM;
240 goto out;
241 }
242 new = 1;
243 }
244
245 if (page != kmapped_page) {
246 if (kmapped_page)
247 kunmap(kmapped_page);
248 kmapped_page = page;
249 kaddr = kmap(kmapped_page);
250 }
251 if (new && offset)
252 memset(kaddr, 0, offset);
253 bytes_to_copy = PAGE_SIZE - offset;
254 if (bytes_to_copy > len) {
255 bytes_to_copy = len;
256 if (new)
257 memset(kaddr+offset+len, 0,
258 PAGE_SIZE-offset-len);
259 }
260 err = copy_from_user(kaddr+offset, str, bytes_to_copy);
261 if (err) {
262 ret = -EFAULT;
263 goto out;
264 }
265
266 pos += bytes_to_copy;
267 str += bytes_to_copy;
268 len -= bytes_to_copy;
269 }
270 }
271 ret = 0;
272out:
273 if (kmapped_page)
274 kunmap(kmapped_page);
275 return ret;
276}
277
278/*
279 * Like copy_strings, but get argv and its values from kernel memory.
280 */
281int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
282{
283 int r;
284 mm_segment_t oldfs = get_fs();
285 set_fs(KERNEL_DS);
286 r = copy_strings(argc, (char __user * __user *)argv, bprm);
287 set_fs(oldfs);
288 return r;
289}
290
291EXPORT_SYMBOL(copy_strings_kernel);
292
293#ifdef CONFIG_MMU
294/*
295 * This routine is used to map in a page into an address space: needed by
296 * execve() for the initial stack and environment pages.
297 *
298 * vma->vm_mm->mmap_sem is held for writing.
299 */
300void install_arg_page(struct vm_area_struct *vma,
301 struct page *page, unsigned long address)
302{
303 struct mm_struct *mm = vma->vm_mm;
304 pgd_t * pgd;
305 pud_t * pud;
306 pmd_t * pmd;
307 pte_t * pte;
308
309 if (unlikely(anon_vma_prepare(vma)))
310 goto out_sig;
311
312 flush_dcache_page(page);
313 pgd = pgd_offset(mm, address);
314
315 spin_lock(&mm->page_table_lock);
316 pud = pud_alloc(mm, pgd, address);
317 if (!pud)
318 goto out;
319 pmd = pmd_alloc(mm, pud, address);
320 if (!pmd)
321 goto out;
322 pte = pte_alloc_map(mm, pmd, address);
323 if (!pte)
324 goto out;
325 if (!pte_none(*pte)) {
326 pte_unmap(pte);
327 goto out;
328 }
329 inc_mm_counter(mm, rss);
330 lru_cache_add_active(page);
331 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
332 page, vma->vm_page_prot))));
333 page_add_anon_rmap(page, vma, address);
334 pte_unmap(pte);
335 spin_unlock(&mm->page_table_lock);
336
337 /* no need for flush_tlb */
338 return;
339out:
340 spin_unlock(&mm->page_table_lock);
341out_sig:
342 __free_page(page);
343 force_sig(SIGKILL, current);
344}
345
346#define EXTRA_STACK_VM_PAGES 20 /* random */
347
348int setup_arg_pages(struct linux_binprm *bprm,
349 unsigned long stack_top,
350 int executable_stack)
351{
352 unsigned long stack_base;
353 struct vm_area_struct *mpnt;
354 struct mm_struct *mm = current->mm;
355 int i, ret;
356 long arg_size;
357
358#ifdef CONFIG_STACK_GROWSUP
359 /* Move the argument and environment strings to the bottom of the
360 * stack space.
361 */
362 int offset, j;
363 char *to, *from;
364
365 /* Start by shifting all the pages down */
366 i = 0;
367 for (j = 0; j < MAX_ARG_PAGES; j++) {
368 struct page *page = bprm->page[j];
369 if (!page)
370 continue;
371 bprm->page[i++] = page;
372 }
373
374 /* Now move them within their pages */
375 offset = bprm->p % PAGE_SIZE;
376 to = kmap(bprm->page[0]);
377 for (j = 1; j < i; j++) {
378 memmove(to, to + offset, PAGE_SIZE - offset);
379 from = kmap(bprm->page[j]);
380 memcpy(to + PAGE_SIZE - offset, from, offset);
381 kunmap(bprm->page[j - 1]);
382 to = from;
383 }
384 memmove(to, to + offset, PAGE_SIZE - offset);
385 kunmap(bprm->page[j - 1]);
386
387 /* Limit stack size to 1GB */
388 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
389 if (stack_base > (1 << 30))
390 stack_base = 1 << 30;
391 stack_base = PAGE_ALIGN(stack_top - stack_base);
392
393 /* Adjust bprm->p to point to the end of the strings. */
394 bprm->p = stack_base + PAGE_SIZE * i - offset;
395
396 mm->arg_start = stack_base;
397 arg_size = i << PAGE_SHIFT;
398
399 /* zero pages that were copied above */
400 while (i < MAX_ARG_PAGES)
401 bprm->page[i++] = NULL;
402#else
403 stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
404 stack_base = PAGE_ALIGN(stack_base);
405 bprm->p += stack_base;
406 mm->arg_start = bprm->p;
407 arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
408#endif
409
410 arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
411
412 if (bprm->loader)
413 bprm->loader += stack_base;
414 bprm->exec += stack_base;
415
416 mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
417 if (!mpnt)
418 return -ENOMEM;
419
420 if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) {
421 kmem_cache_free(vm_area_cachep, mpnt);
422 return -ENOMEM;
423 }
424
425 memset(mpnt, 0, sizeof(*mpnt));
426
427 down_write(&mm->mmap_sem);
428 {
429 mpnt->vm_mm = mm;
430#ifdef CONFIG_STACK_GROWSUP
431 mpnt->vm_start = stack_base;
432 mpnt->vm_end = stack_base + arg_size;
433#else
434 mpnt->vm_end = stack_top;
435 mpnt->vm_start = mpnt->vm_end - arg_size;
436#endif
437 /* Adjust stack execute permissions; explicitly enable
438 * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
439 * and leave alone (arch default) otherwise. */
440 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
441 mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
442 else if (executable_stack == EXSTACK_DISABLE_X)
443 mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
444 else
445 mpnt->vm_flags = VM_STACK_FLAGS;
446 mpnt->vm_flags |= mm->def_flags;
447 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
448 if ((ret = insert_vm_struct(mm, mpnt))) {
449 up_write(&mm->mmap_sem);
450 kmem_cache_free(vm_area_cachep, mpnt);
451 return ret;
452 }
453 mm->stack_vm = mm->total_vm = vma_pages(mpnt);
454 }
455
456 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
457 struct page *page = bprm->page[i];
458 if (page) {
459 bprm->page[i] = NULL;
460 install_arg_page(mpnt, page, stack_base);
461 }
462 stack_base += PAGE_SIZE;
463 }
464 up_write(&mm->mmap_sem);
465
466 return 0;
467}
468
469EXPORT_SYMBOL(setup_arg_pages);
470
471#define free_arg_pages(bprm) do { } while (0)
472
473#else
474
475static inline void free_arg_pages(struct linux_binprm *bprm)
476{
477 int i;
478
479 for (i = 0; i < MAX_ARG_PAGES; i++) {
480 if (bprm->page[i])
481 __free_page(bprm->page[i]);
482 bprm->page[i] = NULL;
483 }
484}
485
486#endif /* CONFIG_MMU */
487
488struct file *open_exec(const char *name)
489{
490 struct nameidata nd;
491 int err;
492 struct file *file;
493
494 nd.intent.open.flags = FMODE_READ;
495 err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
496 file = ERR_PTR(err);
497
498 if (!err) {
499 struct inode *inode = nd.dentry->d_inode;
500 file = ERR_PTR(-EACCES);
501 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
502 S_ISREG(inode->i_mode)) {
503 int err = permission(inode, MAY_EXEC, &nd);
504 if (!err && !(inode->i_mode & 0111))
505 err = -EACCES;
506 file = ERR_PTR(err);
507 if (!err) {
508 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
509 if (!IS_ERR(file)) {
510 err = deny_write_access(file);
511 if (err) {
512 fput(file);
513 file = ERR_PTR(err);
514 }
515 }
516out:
517 return file;
518 }
519 }
520 path_release(&nd);
521 }
522 goto out;
523}
524
525EXPORT_SYMBOL(open_exec);
526
527int kernel_read(struct file *file, unsigned long offset,
528 char *addr, unsigned long count)
529{
530 mm_segment_t old_fs;
531 loff_t pos = offset;
532 int result;
533
534 old_fs = get_fs();
535 set_fs(get_ds());
536 /* The cast to a user pointer is valid due to the set_fs() */
537 result = vfs_read(file, (void __user *)addr, count, &pos);
538 set_fs(old_fs);
539 return result;
540}
541
542EXPORT_SYMBOL(kernel_read);
543
544static int exec_mmap(struct mm_struct *mm)
545{
546 struct task_struct *tsk;
547 struct mm_struct * old_mm, *active_mm;
548
549 /* Notify parent that we're no longer interested in the old VM */
550 tsk = current;
551 old_mm = current->mm;
552 mm_release(tsk, old_mm);
553
554 if (old_mm) {
555 /*
556 * Make sure that if there is a core dump in progress
557 * for the old mm, we get out and die instead of going
558 * through with the exec. We must hold mmap_sem around
559 * checking core_waiters and changing tsk->mm. The
560 * core-inducing thread will increment core_waiters for
561 * each thread whose ->mm == old_mm.
562 */
563 down_read(&old_mm->mmap_sem);
564 if (unlikely(old_mm->core_waiters)) {
565 up_read(&old_mm->mmap_sem);
566 return -EINTR;
567 }
568 }
569 task_lock(tsk);
570 active_mm = tsk->active_mm;
571 tsk->mm = mm;
572 tsk->active_mm = mm;
573 activate_mm(active_mm, mm);
574 task_unlock(tsk);
575 arch_pick_mmap_layout(mm);
576 if (old_mm) {
577 up_read(&old_mm->mmap_sem);
578 if (active_mm != old_mm) BUG();
579 mmput(old_mm);
580 return 0;
581 }
582 mmdrop(active_mm);
583 return 0;
584}
585
586/*
587 * This function makes sure the current process has its own signal table,
588 * so that flush_signal_handlers can later reset the handlers without
589 * disturbing other processes. (Other processes might share the signal
590 * table via the CLONE_SIGHAND option to clone().)
591 */
592static inline int de_thread(struct task_struct *tsk)
593{
594 struct signal_struct *sig = tsk->signal;
595 struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
596 spinlock_t *lock = &oldsighand->siglock;
597 int count;
598
599 /*
600 * If we don't share sighandlers, then we aren't sharing anything
601 * and we can just re-use it all.
602 */
603 if (atomic_read(&oldsighand->count) <= 1) {
604 BUG_ON(atomic_read(&sig->count) != 1);
605 exit_itimers(sig);
606 return 0;
607 }
608
609 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
610 if (!newsighand)
611 return -ENOMEM;
612
613 if (thread_group_empty(current))
614 goto no_thread_group;
615
616 /*
617 * Kill all other threads in the thread group.
618 * We must hold tasklist_lock to call zap_other_threads.
619 */
620 read_lock(&tasklist_lock);
621 spin_lock_irq(lock);
622 if (sig->flags & SIGNAL_GROUP_EXIT) {
623 /*
624 * Another group action in progress, just
625 * return so that the signal is processed.
626 */
627 spin_unlock_irq(lock);
628 read_unlock(&tasklist_lock);
629 kmem_cache_free(sighand_cachep, newsighand);
630 return -EAGAIN;
631 }
632 zap_other_threads(current);
633 read_unlock(&tasklist_lock);
634
635 /*
636 * Account for the thread group leader hanging around:
637 */
638 count = 2;
639 if (thread_group_leader(current))
640 count = 1;
641 while (atomic_read(&sig->count) > count) {
642 sig->group_exit_task = current;
643 sig->notify_count = count;
644 __set_current_state(TASK_UNINTERRUPTIBLE);
645 spin_unlock_irq(lock);
646 schedule();
647 spin_lock_irq(lock);
648 }
649 sig->group_exit_task = NULL;
650 sig->notify_count = 0;
651 spin_unlock_irq(lock);
652
653 /*
654 * At this point all other threads have exited, all we have to
655 * do is to wait for the thread group leader to become inactive,
656 * and to assume its PID:
657 */
658 if (!thread_group_leader(current)) {
659 struct task_struct *leader = current->group_leader, *parent;
660 struct dentry *proc_dentry1, *proc_dentry2;
661 unsigned long exit_state, ptrace;
662
663 /*
664 * Wait for the thread group leader to be a zombie.
665 * It should already be zombie at this point, most
666 * of the time.
667 */
668 while (leader->exit_state != EXIT_ZOMBIE)
669 yield();
670
671 spin_lock(&leader->proc_lock);
672 spin_lock(&current->proc_lock);
673 proc_dentry1 = proc_pid_unhash(current);
674 proc_dentry2 = proc_pid_unhash(leader);
675 write_lock_irq(&tasklist_lock);
676
677 if (leader->tgid != current->tgid)
678 BUG();
679 if (current->pid == current->tgid)
680 BUG();
681 /*
682 * An exec() starts a new thread group with the
683 * TGID of the previous thread group. Rehash the
684 * two threads with a switched PID, and release
685 * the former thread group leader:
686 */
687 ptrace = leader->ptrace;
688 parent = leader->parent;
689 if (unlikely(ptrace) && unlikely(parent == current)) {
690 /*
691 * Joker was ptracing his own group leader,
692 * and now he wants to be his own parent!
693 * We can't have that.
694 */
695 ptrace = 0;
696 }
697
698 ptrace_unlink(current);
699 ptrace_unlink(leader);
700 remove_parent(current);
701 remove_parent(leader);
702
703 switch_exec_pids(leader, current);
704
705 current->parent = current->real_parent = leader->real_parent;
706 leader->parent = leader->real_parent = child_reaper;
707 current->group_leader = current;
708 leader->group_leader = leader;
709
710 add_parent(current, current->parent);
711 add_parent(leader, leader->parent);
712 if (ptrace) {
713 current->ptrace = ptrace;
714 __ptrace_link(current, parent);
715 }
716
717 list_del(&current->tasks);
718 list_add_tail(&current->tasks, &init_task.tasks);
719 current->exit_signal = SIGCHLD;
720 exit_state = leader->exit_state;
721
722 write_unlock_irq(&tasklist_lock);
723 spin_unlock(&leader->proc_lock);
724 spin_unlock(&current->proc_lock);
725 proc_pid_flush(proc_dentry1);
726 proc_pid_flush(proc_dentry2);
727
728 if (exit_state != EXIT_ZOMBIE)
729 BUG();
730 release_task(leader);
731 }
732
733 /*
734 * Now there are really no other threads at all,
735 * so it's safe to stop telling them to kill themselves.
736 */
737 sig->flags = 0;
738
739no_thread_group:
740 BUG_ON(atomic_read(&sig->count) != 1);
741 exit_itimers(sig);
742
743 if (atomic_read(&oldsighand->count) == 1) {
744 /*
745 * Now that we nuked the rest of the thread group,
746 * it turns out we are not sharing sighand any more either.
747 * So we can just keep it.
748 */
749 kmem_cache_free(sighand_cachep, newsighand);
750 } else {
751 /*
752 * Move our state over to newsighand and switch it in.
753 */
754 spin_lock_init(&newsighand->siglock);
755 atomic_set(&newsighand->count, 1);
756 memcpy(newsighand->action, oldsighand->action,
757 sizeof(newsighand->action));
758
759 write_lock_irq(&tasklist_lock);
760 spin_lock(&oldsighand->siglock);
761 spin_lock(&newsighand->siglock);
762
763 current->sighand = newsighand;
764 recalc_sigpending();
765
766 spin_unlock(&newsighand->siglock);
767 spin_unlock(&oldsighand->siglock);
768 write_unlock_irq(&tasklist_lock);
769
770 if (atomic_dec_and_test(&oldsighand->count))
771 kmem_cache_free(sighand_cachep, oldsighand);
772 }
773
774 if (!thread_group_empty(current))
775 BUG();
776 if (!thread_group_leader(current))
777 BUG();
778 return 0;
779}
780
781/*
782 * These functions flushes out all traces of the currently running executable
783 * so that a new one can be started
784 */
785
786static inline void flush_old_files(struct files_struct * files)
787{
788 long j = -1;
789
790 spin_lock(&files->file_lock);
791 for (;;) {
792 unsigned long set, i;
793
794 j++;
795 i = j * __NFDBITS;
796 if (i >= files->max_fds || i >= files->max_fdset)
797 break;
798 set = files->close_on_exec->fds_bits[j];
799 if (!set)
800 continue;
801 files->close_on_exec->fds_bits[j] = 0;
802 spin_unlock(&files->file_lock);
803 for ( ; set ; i++,set >>= 1) {
804 if (set & 1) {
805 sys_close(i);
806 }
807 }
808 spin_lock(&files->file_lock);
809
810 }
811 spin_unlock(&files->file_lock);
812}
813
814void get_task_comm(char *buf, struct task_struct *tsk)
815{
816 /* buf must be at least sizeof(tsk->comm) in size */
817 task_lock(tsk);
818 strncpy(buf, tsk->comm, sizeof(tsk->comm));
819 task_unlock(tsk);
820}
821
822void set_task_comm(struct task_struct *tsk, char *buf)
823{
824 task_lock(tsk);
825 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
826 task_unlock(tsk);
827}
828
829int flush_old_exec(struct linux_binprm * bprm)
830{
831 char * name;
832 int i, ch, retval;
833 struct files_struct *files;
834 char tcomm[sizeof(current->comm)];
835
836 /*
837 * Make sure we have a private signal table and that
838 * we are unassociated from the previous thread group.
839 */
840 retval = de_thread(current);
841 if (retval)
842 goto out;
843
844 /*
845 * Make sure we have private file handles. Ask the
846 * fork helper to do the work for us and the exit
847 * helper to do the cleanup of the old one.
848 */
849 files = current->files; /* refcounted so safe to hold */
850 retval = unshare_files();
851 if (retval)
852 goto out;
853 /*
854 * Release all of the old mmap stuff
855 */
856 retval = exec_mmap(bprm->mm);
857 if (retval)
858 goto mmap_failed;
859
860 bprm->mm = NULL; /* We're using it now */
861
862 /* This is the point of no return */
863 steal_locks(files);
864 put_files_struct(files);
865
866 current->sas_ss_sp = current->sas_ss_size = 0;
867
868 if (current->euid == current->uid && current->egid == current->gid)
869 current->mm->dumpable = 1;
870 name = bprm->filename;
871 for (i=0; (ch = *(name++)) != '\0';) {
872 if (ch == '/')
873 i = 0;
874 else
875 if (i < (sizeof(tcomm) - 1))
876 tcomm[i++] = ch;
877 }
878 tcomm[i] = '\0';
879 set_task_comm(current, tcomm);
880
881 current->flags &= ~PF_RANDOMIZE;
882 flush_thread();
883
884 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
885 permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
886 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
887 suid_keys(current);
888 current->mm->dumpable = 0;
889 }
890
891 /* An exec changes our domain. We are no longer part of the thread
892 group */
893
894 current->self_exec_id++;
895
896 flush_signal_handlers(current, 0);
897 flush_old_files(current->files);
898
899 return 0;
900
901mmap_failed:
902 put_files_struct(current->files);
903 current->files = files;
904out:
905 return retval;
906}
907
908EXPORT_SYMBOL(flush_old_exec);
909
910/*
911 * Fill the binprm structure from the inode.
912 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
913 */
914int prepare_binprm(struct linux_binprm *bprm)
915{
916 int mode;
917 struct inode * inode = bprm->file->f_dentry->d_inode;
918 int retval;
919
920 mode = inode->i_mode;
921 /*
922 * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
923 * generic_permission lets a non-executable through
924 */
925 if (!(mode & 0111)) /* with at least _one_ execute bit set */
926 return -EACCES;
927 if (bprm->file->f_op == NULL)
928 return -EACCES;
929
930 bprm->e_uid = current->euid;
931 bprm->e_gid = current->egid;
932
933 if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
934 /* Set-uid? */
935 if (mode & S_ISUID) {
936 current->personality &= ~PER_CLEAR_ON_SETID;
937 bprm->e_uid = inode->i_uid;
938 }
939
940 /* Set-gid? */
941 /*
942 * If setgid is set but no group execute bit then this
943 * is a candidate for mandatory locking, not a setgid
944 * executable.
945 */
946 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
947 current->personality &= ~PER_CLEAR_ON_SETID;
948 bprm->e_gid = inode->i_gid;
949 }
950 }
951
952 /* fill in binprm security blob */
953 retval = security_bprm_set(bprm);
954 if (retval)
955 return retval;
956
957 memset(bprm->buf,0,BINPRM_BUF_SIZE);
958 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
959}
960
961EXPORT_SYMBOL(prepare_binprm);
962
963static inline int unsafe_exec(struct task_struct *p)
964{
965 int unsafe = 0;
966 if (p->ptrace & PT_PTRACED) {
967 if (p->ptrace & PT_PTRACE_CAP)
968 unsafe |= LSM_UNSAFE_PTRACE_CAP;
969 else
970 unsafe |= LSM_UNSAFE_PTRACE;
971 }
972 if (atomic_read(&p->fs->count) > 1 ||
973 atomic_read(&p->files->count) > 1 ||
974 atomic_read(&p->sighand->count) > 1)
975 unsafe |= LSM_UNSAFE_SHARE;
976
977 return unsafe;
978}
979
980void compute_creds(struct linux_binprm *bprm)
981{
982 int unsafe;
983
984 if (bprm->e_uid != current->uid)
985 suid_keys(current);
986 exec_keys(current);
987
988 task_lock(current);
989 unsafe = unsafe_exec(current);
990 security_bprm_apply_creds(bprm, unsafe);
991 task_unlock(current);
992 security_bprm_post_apply_creds(bprm);
993}
994
995EXPORT_SYMBOL(compute_creds);
996
997void remove_arg_zero(struct linux_binprm *bprm)
998{
999 if (bprm->argc) {
1000 unsigned long offset;
1001 char * kaddr;
1002 struct page *page;
1003
1004 offset = bprm->p % PAGE_SIZE;
1005 goto inside;
1006
1007 while (bprm->p++, *(kaddr+offset++)) {
1008 if (offset != PAGE_SIZE)
1009 continue;
1010 offset = 0;
1011 kunmap_atomic(kaddr, KM_USER0);
1012inside:
1013 page = bprm->page[bprm->p/PAGE_SIZE];
1014 kaddr = kmap_atomic(page, KM_USER0);
1015 }
1016 kunmap_atomic(kaddr, KM_USER0);
1017 bprm->argc--;
1018 }
1019}
1020
1021EXPORT_SYMBOL(remove_arg_zero);
1022
1023/*
1024 * cycle the list of binary formats handler, until one recognizes the image
1025 */
1026int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1027{
1028 int try,retval;
1029 struct linux_binfmt *fmt;
1030#ifdef __alpha__
1031 /* handle /sbin/loader.. */
1032 {
1033 struct exec * eh = (struct exec *) bprm->buf;
1034
1035 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1036 (eh->fh.f_flags & 0x3000) == 0x3000)
1037 {
1038 struct file * file;
1039 unsigned long loader;
1040
1041 allow_write_access(bprm->file);
1042 fput(bprm->file);
1043 bprm->file = NULL;
1044
1045 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1046
1047 file = open_exec("/sbin/loader");
1048 retval = PTR_ERR(file);
1049 if (IS_ERR(file))
1050 return retval;
1051
1052 /* Remember if the application is TASO. */
1053 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1054
1055 bprm->file = file;
1056 bprm->loader = loader;
1057 retval = prepare_binprm(bprm);
1058 if (retval<0)
1059 return retval;
1060 /* should call search_binary_handler recursively here,
1061 but it does not matter */
1062 }
1063 }
1064#endif
1065 retval = security_bprm_check(bprm);
1066 if (retval)
1067 return retval;
1068
1069 /* kernel module loader fixup */
1070 /* so we don't try to load run modprobe in kernel space. */
1071 set_fs(USER_DS);
1072 retval = -ENOENT;
1073 for (try=0; try<2; try++) {
1074 read_lock(&binfmt_lock);
1075 for (fmt = formats ; fmt ; fmt = fmt->next) {
1076 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1077 if (!fn)
1078 continue;
1079 if (!try_module_get(fmt->module))
1080 continue;
1081 read_unlock(&binfmt_lock);
1082 retval = fn(bprm, regs);
1083 if (retval >= 0) {
1084 put_binfmt(fmt);
1085 allow_write_access(bprm->file);
1086 if (bprm->file)
1087 fput(bprm->file);
1088 bprm->file = NULL;
1089 current->did_exec = 1;
1090 return retval;
1091 }
1092 read_lock(&binfmt_lock);
1093 put_binfmt(fmt);
1094 if (retval != -ENOEXEC || bprm->mm == NULL)
1095 break;
1096 if (!bprm->file) {
1097 read_unlock(&binfmt_lock);
1098 return retval;
1099 }
1100 }
1101 read_unlock(&binfmt_lock);
1102 if (retval != -ENOEXEC || bprm->mm == NULL) {
1103 break;
1104#ifdef CONFIG_KMOD
1105 }else{
1106#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1107 if (printable(bprm->buf[0]) &&
1108 printable(bprm->buf[1]) &&
1109 printable(bprm->buf[2]) &&
1110 printable(bprm->buf[3]))
1111 break; /* -ENOEXEC */
1112 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1113#endif
1114 }
1115 }
1116 return retval;
1117}
1118
1119EXPORT_SYMBOL(search_binary_handler);
1120
1121/*
1122 * sys_execve() executes a new program.
1123 */
1124int do_execve(char * filename,
1125 char __user *__user *argv,
1126 char __user *__user *envp,
1127 struct pt_regs * regs)
1128{
1129 struct linux_binprm *bprm;
1130 struct file *file;
1131 int retval;
1132 int i;
1133
1134 retval = -ENOMEM;
1135 bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
1136 if (!bprm)
1137 goto out_ret;
1138 memset(bprm, 0, sizeof(*bprm));
1139
1140 file = open_exec(filename);
1141 retval = PTR_ERR(file);
1142 if (IS_ERR(file))
1143 goto out_kfree;
1144
1145 sched_exec();
1146
1147 bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
1148
1149 bprm->file = file;
1150 bprm->filename = filename;
1151 bprm->interp = filename;
1152 bprm->mm = mm_alloc();
1153 retval = -ENOMEM;
1154 if (!bprm->mm)
1155 goto out_file;
1156
1157 retval = init_new_context(current, bprm->mm);
1158 if (retval < 0)
1159 goto out_mm;
1160
1161 bprm->argc = count(argv, bprm->p / sizeof(void *));
1162 if ((retval = bprm->argc) < 0)
1163 goto out_mm;
1164
1165 bprm->envc = count(envp, bprm->p / sizeof(void *));
1166 if ((retval = bprm->envc) < 0)
1167 goto out_mm;
1168
1169 retval = security_bprm_alloc(bprm);
1170 if (retval)
1171 goto out;
1172
1173 retval = prepare_binprm(bprm);
1174 if (retval < 0)
1175 goto out;
1176
1177 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1178 if (retval < 0)
1179 goto out;
1180
1181 bprm->exec = bprm->p;
1182 retval = copy_strings(bprm->envc, envp, bprm);
1183 if (retval < 0)
1184 goto out;
1185
1186 retval = copy_strings(bprm->argc, argv, bprm);
1187 if (retval < 0)
1188 goto out;
1189
1190 retval = search_binary_handler(bprm,regs);
1191 if (retval >= 0) {
1192 free_arg_pages(bprm);
1193
1194 /* execve success */
1195 security_bprm_free(bprm);
1196 acct_update_integrals(current);
1197 update_mem_hiwater(current);
1198 kfree(bprm);
1199 return retval;
1200 }
1201
1202out:
1203 /* Something went wrong, return the inode and free the argument pages*/
1204 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
1205 struct page * page = bprm->page[i];
1206 if (page)
1207 __free_page(page);
1208 }
1209
1210 if (bprm->security)
1211 security_bprm_free(bprm);
1212
1213out_mm:
1214 if (bprm->mm)
1215 mmdrop(bprm->mm);
1216
1217out_file:
1218 if (bprm->file) {
1219 allow_write_access(bprm->file);
1220 fput(bprm->file);
1221 }
1222
1223out_kfree:
1224 kfree(bprm);
1225
1226out_ret:
1227 return retval;
1228}
1229
1230int set_binfmt(struct linux_binfmt *new)
1231{
1232 struct linux_binfmt *old = current->binfmt;
1233
1234 if (new) {
1235 if (!try_module_get(new->module))
1236 return -1;
1237 }
1238 current->binfmt = new;
1239 if (old)
1240 module_put(old->module);
1241 return 0;
1242}
1243
1244EXPORT_SYMBOL(set_binfmt);
1245
1246#define CORENAME_MAX_SIZE 64
1247
1248/* format_corename will inspect the pattern parameter, and output a
1249 * name into corename, which must have space for at least
1250 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1251 */
1252static void format_corename(char *corename, const char *pattern, long signr)
1253{
1254 const char *pat_ptr = pattern;
1255 char *out_ptr = corename;
1256 char *const out_end = corename + CORENAME_MAX_SIZE;
1257 int rc;
1258 int pid_in_pattern = 0;
1259
1260 /* Repeat as long as we have more pattern to process and more output
1261 space */
1262 while (*pat_ptr) {
1263 if (*pat_ptr != '%') {
1264 if (out_ptr == out_end)
1265 goto out;
1266 *out_ptr++ = *pat_ptr++;
1267 } else {
1268 switch (*++pat_ptr) {
1269 case 0:
1270 goto out;
1271 /* Double percent, output one percent */
1272 case '%':
1273 if (out_ptr == out_end)
1274 goto out;
1275 *out_ptr++ = '%';
1276 break;
1277 /* pid */
1278 case 'p':
1279 pid_in_pattern = 1;
1280 rc = snprintf(out_ptr, out_end - out_ptr,
1281 "%d", current->tgid);
1282 if (rc > out_end - out_ptr)
1283 goto out;
1284 out_ptr += rc;
1285 break;
1286 /* uid */
1287 case 'u':
1288 rc = snprintf(out_ptr, out_end - out_ptr,
1289 "%d", current->uid);
1290 if (rc > out_end - out_ptr)
1291 goto out;
1292 out_ptr += rc;
1293 break;
1294 /* gid */
1295 case 'g':
1296 rc = snprintf(out_ptr, out_end - out_ptr,
1297 "%d", current->gid);
1298 if (rc > out_end - out_ptr)
1299 goto out;
1300 out_ptr += rc;
1301 break;
1302 /* signal that caused the coredump */
1303 case 's':
1304 rc = snprintf(out_ptr, out_end - out_ptr,
1305 "%ld", signr);
1306 if (rc > out_end - out_ptr)
1307 goto out;
1308 out_ptr += rc;
1309 break;
1310 /* UNIX time of coredump */
1311 case 't': {
1312 struct timeval tv;
1313 do_gettimeofday(&tv);
1314 rc = snprintf(out_ptr, out_end - out_ptr,
1315 "%lu", tv.tv_sec);
1316 if (rc > out_end - out_ptr)
1317 goto out;
1318 out_ptr += rc;
1319 break;
1320 }
1321 /* hostname */
1322 case 'h':
1323 down_read(&uts_sem);
1324 rc = snprintf(out_ptr, out_end - out_ptr,
1325 "%s", system_utsname.nodename);
1326 up_read(&uts_sem);
1327 if (rc > out_end - out_ptr)
1328 goto out;
1329 out_ptr += rc;
1330 break;
1331 /* executable */
1332 case 'e':
1333 rc = snprintf(out_ptr, out_end - out_ptr,
1334 "%s", current->comm);
1335 if (rc > out_end - out_ptr)
1336 goto out;
1337 out_ptr += rc;
1338 break;
1339 default:
1340 break;
1341 }
1342 ++pat_ptr;
1343 }
1344 }
1345 /* Backward compatibility with core_uses_pid:
1346 *
1347 * If core_pattern does not include a %p (as is the default)
1348 * and core_uses_pid is set, then .%pid will be appended to
1349 * the filename */
1350 if (!pid_in_pattern
1351 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1352 rc = snprintf(out_ptr, out_end - out_ptr,
1353 ".%d", current->tgid);
1354 if (rc > out_end - out_ptr)
1355 goto out;
1356 out_ptr += rc;
1357 }
1358 out:
1359 *out_ptr = 0;
1360}
1361
1362static void zap_threads (struct mm_struct *mm)
1363{
1364 struct task_struct *g, *p;
1365 struct task_struct *tsk = current;
1366 struct completion *vfork_done = tsk->vfork_done;
1367 int traced = 0;
1368
1369 /*
1370 * Make sure nobody is waiting for us to release the VM,
1371 * otherwise we can deadlock when we wait on each other
1372 */
1373 if (vfork_done) {
1374 tsk->vfork_done = NULL;
1375 complete(vfork_done);
1376 }
1377
1378 read_lock(&tasklist_lock);
1379 do_each_thread(g,p)
1380 if (mm == p->mm && p != tsk) {
1381 force_sig_specific(SIGKILL, p);
1382 mm->core_waiters++;
1383 if (unlikely(p->ptrace) &&
1384 unlikely(p->parent->mm == mm))
1385 traced = 1;
1386 }
1387 while_each_thread(g,p);
1388
1389 read_unlock(&tasklist_lock);
1390
1391 if (unlikely(traced)) {
1392 /*
1393 * We are zapping a thread and the thread it ptraces.
1394 * If the tracee went into a ptrace stop for exit tracing,
1395 * we could deadlock since the tracer is waiting for this
1396 * coredump to finish. Detach them so they can both die.
1397 */
1398 write_lock_irq(&tasklist_lock);
1399 do_each_thread(g,p) {
1400 if (mm == p->mm && p != tsk &&
1401 p->ptrace && p->parent->mm == mm) {
1402 __ptrace_unlink(p);
1403 }
1404 } while_each_thread(g,p);
1405 write_unlock_irq(&tasklist_lock);
1406 }
1407}
1408
1409static void coredump_wait(struct mm_struct *mm)
1410{
1411 DECLARE_COMPLETION(startup_done);
1412
1413 mm->core_waiters++; /* let other threads block */
1414 mm->core_startup_done = &startup_done;
1415
1416 /* give other threads a chance to run: */
1417 yield();
1418
1419 zap_threads(mm);
1420 if (--mm->core_waiters) {
1421 up_write(&mm->mmap_sem);
1422 wait_for_completion(&startup_done);
1423 } else
1424 up_write(&mm->mmap_sem);
1425 BUG_ON(mm->core_waiters);
1426}
1427
1428int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1429{
1430 char corename[CORENAME_MAX_SIZE + 1];
1431 struct mm_struct *mm = current->mm;
1432 struct linux_binfmt * binfmt;
1433 struct inode * inode;
1434 struct file * file;
1435 int retval = 0;
1436
1437 binfmt = current->binfmt;
1438 if (!binfmt || !binfmt->core_dump)
1439 goto fail;
1440 down_write(&mm->mmap_sem);
1441 if (!mm->dumpable) {
1442 up_write(&mm->mmap_sem);
1443 goto fail;
1444 }
1445 mm->dumpable = 0;
1446 init_completion(&mm->core_done);
1447 spin_lock_irq(&current->sighand->siglock);
1448 current->signal->flags = SIGNAL_GROUP_EXIT;
1449 current->signal->group_exit_code = exit_code;
1450 spin_unlock_irq(&current->sighand->siglock);
1451 coredump_wait(mm);
1452
1453 /*
1454 * Clear any false indication of pending signals that might
1455 * be seen by the filesystem code called to write the core file.
1456 */
1457 current->signal->group_stop_count = 0;
1458 clear_thread_flag(TIF_SIGPENDING);
1459
1460 if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
1461 goto fail_unlock;
1462
1463 /*
1464 * lock_kernel() because format_corename() is controlled by sysctl, which
1465 * uses lock_kernel()
1466 */
1467 lock_kernel();
1468 format_corename(corename, core_pattern, signr);
1469 unlock_kernel();
1470 file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600);
1471 if (IS_ERR(file))
1472 goto fail_unlock;
1473 inode = file->f_dentry->d_inode;
1474 if (inode->i_nlink > 1)
1475 goto close_fail; /* multiple links - don't dump */
1476 if (d_unhashed(file->f_dentry))
1477 goto close_fail;
1478
1479 if (!S_ISREG(inode->i_mode))
1480 goto close_fail;
1481 if (!file->f_op)
1482 goto close_fail;
1483 if (!file->f_op->write)
1484 goto close_fail;
1485 if (do_truncate(file->f_dentry, 0) != 0)
1486 goto close_fail;
1487
1488 retval = binfmt->core_dump(signr, regs, file);
1489
1490 if (retval)
1491 current->signal->group_exit_code |= 0x80;
1492close_fail:
1493 filp_close(file, NULL);
1494fail_unlock:
1495 complete_all(&mm->core_done);
1496fail:
1497 return retval;
1498}