blob: 434dba778ccc761befe61c26a62f26037993ba32 [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>
Al Viro9f3acc32008-04-24 07:44:08 -040027#include <linux/fdtable.h>
Hugh Dickinsba92a432008-07-25 01:45:43 -070028#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/stat.h>
30#include <linux/fcntl.h>
31#include <linux/smp_lock.h>
Hugh Dickinsba92a432008-07-25 01:45:43 -070032#include <linux/swap.h>
Neil Horman74aadce2007-10-16 23:26:35 -070033#include <linux/string.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/init.h>
Hugh Dickinsca5b1722008-07-28 15:46:18 -070035#include <linux/pagemap.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020036#include <linux/perf_event.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#include <linux/highmem.h>
38#include <linux/spinlock.h>
39#include <linux/key.h>
40#include <linux/personality.h>
41#include <linux/binfmts.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/utsname.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080043#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#include <linux/module.h>
45#include <linux/namei.h>
46#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/mount.h>
48#include <linux/security.h>
Mimi Zohar6146f0d2009-02-04 09:06:57 -050049#include <linux/ima.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#include <linux/syscalls.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070051#include <linux/tsacct_kern.h>
Matt Helsley9f460802005-11-07 00:59:16 -080052#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040053#include <linux/audit.h>
Roland McGrath6341c392008-07-25 19:45:44 -070054#include <linux/tracehook.h>
Johannes Berg5f4123b2008-07-09 10:28:40 +020055#include <linux/kmod.h>
Eric Paris6110e3a2008-12-17 13:53:20 -050056#include <linux/fsnotify.h>
Al Viro5ad4e532009-03-29 19:50:06 -040057#include <linux/fs_struct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59#include <asm/uaccess.h>
60#include <asm/mmu_context.h>
Ollie Wildb6a2fea2007-07-19 01:48:16 -070061#include <asm/tlb.h>
David Howellsa6f76f22008-11-14 10:39:24 +110062#include "internal.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
Linus Torvalds1da177e2005-04-16 15:20:36 -070064int core_uses_pid;
Dan Aloni71ce92f2007-05-16 22:11:16 -070065char core_pattern[CORENAME_MAX_SIZE] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070066int suid_dumpable = 0;
67
Linus Torvalds1da177e2005-04-16 15:20:36 -070068/* The maximal length of core_pattern is also specified in sysctl.c */
69
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070070static LIST_HEAD(formats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071static DEFINE_RWLOCK(binfmt_lock);
72
Ivan Kokshaysky74641f52009-04-30 15:08:49 -070073int __register_binfmt(struct linux_binfmt * fmt, int insert)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074{
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 if (!fmt)
76 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 write_lock(&binfmt_lock);
Ivan Kokshaysky74641f52009-04-30 15:08:49 -070078 insert ? list_add(&fmt->lh, &formats) :
79 list_add_tail(&fmt->lh, &formats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 write_unlock(&binfmt_lock);
81 return 0;
82}
83
Ivan Kokshaysky74641f52009-04-30 15:08:49 -070084EXPORT_SYMBOL(__register_binfmt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Alexey Dobriyanf6b450d2007-10-16 23:26:04 -070086void unregister_binfmt(struct linux_binfmt * fmt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087{
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 write_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070089 list_del(&fmt->lh);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 write_unlock(&binfmt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091}
92
93EXPORT_SYMBOL(unregister_binfmt);
94
95static inline void put_binfmt(struct linux_binfmt * fmt)
96{
97 module_put(fmt->module);
98}
99
100/*
101 * Note that a shared library must be both readable and executable due to
102 * security reasons.
103 *
104 * Also note that we take the address to load from from the file itself.
105 */
Heiko Carstens1e7bfb22009-01-14 14:14:29 +0100106SYSCALL_DEFINE1(uselib, const char __user *, library)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
Al Viro964bd182008-07-26 03:33:14 -0400108 struct file *file;
Al Viro964bd182008-07-26 03:33:14 -0400109 char *tmp = getname(library);
110 int error = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
Al Viro6e8341a2009-04-06 11:16:22 -0400112 if (IS_ERR(tmp))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 goto out;
114
Al Viro6e8341a2009-04-06 11:16:22 -0400115 file = do_filp_open(AT_FDCWD, tmp,
116 O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
117 MAY_READ | MAY_EXEC | MAY_OPEN);
118 putname(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 error = PTR_ERR(file);
120 if (IS_ERR(file))
121 goto out;
122
Al Viro6e8341a2009-04-06 11:16:22 -0400123 error = -EINVAL;
124 if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
125 goto exit;
126
127 error = -EACCES;
128 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
129 goto exit;
130
Eric Paris6110e3a2008-12-17 13:53:20 -0500131 fsnotify_open(file->f_path.dentry);
132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 error = -ENOEXEC;
134 if(file->f_op) {
135 struct linux_binfmt * fmt;
136
137 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -0700138 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 if (!fmt->load_shlib)
140 continue;
141 if (!try_module_get(fmt->module))
142 continue;
143 read_unlock(&binfmt_lock);
144 error = fmt->load_shlib(file);
145 read_lock(&binfmt_lock);
146 put_binfmt(fmt);
147 if (error != -ENOEXEC)
148 break;
149 }
150 read_unlock(&binfmt_lock);
151 }
Al Viro6e8341a2009-04-06 11:16:22 -0400152exit:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 fput(file);
154out:
155 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156}
157
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700158#ifdef CONFIG_MMU
159
160static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
161 int write)
162{
163 struct page *page;
164 int ret;
165
166#ifdef CONFIG_STACK_GROWSUP
167 if (write) {
168 ret = expand_stack_downwards(bprm->vma, pos);
169 if (ret < 0)
170 return NULL;
171 }
172#endif
173 ret = get_user_pages(current, bprm->mm, pos,
174 1, write, 1, &page, NULL);
175 if (ret <= 0)
176 return NULL;
177
178 if (write) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700179 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800180 struct rlimit *rlim;
181
182 /*
183 * We've historically supported up to 32 pages (ARG_MAX)
184 * of argument strings even with small stacks
185 */
186 if (size <= ARG_MAX)
187 return page;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700188
189 /*
190 * Limit to 1/4-th the stack size for the argv+env strings.
191 * This ensures that:
192 * - the remaining binfmt code will not run out of stack space,
193 * - the program will have a reasonable amount of stack left
194 * to work from.
195 */
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800196 rlim = current->signal->rlim;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700197 if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
198 put_page(page);
199 return NULL;
200 }
201 }
202
203 return page;
204}
205
206static void put_arg_page(struct page *page)
207{
208 put_page(page);
209}
210
211static void free_arg_page(struct linux_binprm *bprm, int i)
212{
213}
214
215static void free_arg_pages(struct linux_binprm *bprm)
216{
217}
218
219static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
220 struct page *page)
221{
222 flush_cache_page(bprm->vma, pos, page_to_pfn(page));
223}
224
225static int __bprm_mm_init(struct linux_binprm *bprm)
226{
Luiz Fernando N. Capitulinoeaccbfa2009-01-06 14:40:44 -0800227 int err;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700228 struct vm_area_struct *vma = NULL;
229 struct mm_struct *mm = bprm->mm;
230
231 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
232 if (!vma)
Luiz Fernando N. Capitulinoeaccbfa2009-01-06 14:40:44 -0800233 return -ENOMEM;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700234
235 down_write(&mm->mmap_sem);
236 vma->vm_mm = mm;
237
238 /*
239 * Place the stack at the largest stack address the architecture
240 * supports. Later, we'll move this to an appropriate place. We don't
241 * use STACK_TOP because that can depend on attributes which aren't
242 * configured yet.
243 */
244 vma->vm_end = STACK_TOP_MAX;
245 vma->vm_start = vma->vm_end - PAGE_SIZE;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700246 vma->vm_flags = VM_STACK_FLAGS;
Coly Li3ed75eb2007-10-18 23:39:15 -0700247 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700248 err = insert_vm_struct(mm, vma);
Luiz Fernando N. Capitulinoeaccbfa2009-01-06 14:40:44 -0800249 if (err)
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700250 goto err;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700251
252 mm->stack_vm = mm->total_vm = 1;
253 up_write(&mm->mmap_sem);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700254 bprm->p = vma->vm_end - sizeof(void *);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700255 return 0;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700256err:
Luiz Fernando N. Capitulinoeaccbfa2009-01-06 14:40:44 -0800257 up_write(&mm->mmap_sem);
258 bprm->vma = NULL;
259 kmem_cache_free(vm_area_cachep, vma);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700260 return err;
261}
262
263static bool valid_arg_len(struct linux_binprm *bprm, long len)
264{
265 return len <= MAX_ARG_STRLEN;
266}
267
268#else
269
270static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
271 int write)
272{
273 struct page *page;
274
275 page = bprm->page[pos / PAGE_SIZE];
276 if (!page && write) {
277 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
278 if (!page)
279 return NULL;
280 bprm->page[pos / PAGE_SIZE] = page;
281 }
282
283 return page;
284}
285
286static void put_arg_page(struct page *page)
287{
288}
289
290static void free_arg_page(struct linux_binprm *bprm, int i)
291{
292 if (bprm->page[i]) {
293 __free_page(bprm->page[i]);
294 bprm->page[i] = NULL;
295 }
296}
297
298static void free_arg_pages(struct linux_binprm *bprm)
299{
300 int i;
301
302 for (i = 0; i < MAX_ARG_PAGES; i++)
303 free_arg_page(bprm, i);
304}
305
306static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
307 struct page *page)
308{
309}
310
311static int __bprm_mm_init(struct linux_binprm *bprm)
312{
313 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
314 return 0;
315}
316
317static bool valid_arg_len(struct linux_binprm *bprm, long len)
318{
319 return len <= bprm->p;
320}
321
322#endif /* CONFIG_MMU */
323
324/*
325 * Create a new mm_struct and populate it with a temporary stack
326 * vm_area_struct. We don't have enough context at this point to set the stack
327 * flags, permissions, and offset, so we use temporary values. We'll update
328 * them later in setup_arg_pages().
329 */
330int bprm_mm_init(struct linux_binprm *bprm)
331{
332 int err;
333 struct mm_struct *mm = NULL;
334
335 bprm->mm = mm = mm_alloc();
336 err = -ENOMEM;
337 if (!mm)
338 goto err;
339
340 err = init_new_context(current, mm);
341 if (err)
342 goto err;
343
344 err = __bprm_mm_init(bprm);
345 if (err)
346 goto err;
347
348 return 0;
349
350err:
351 if (mm) {
352 bprm->mm = NULL;
353 mmdrop(mm);
354 }
355
356 return err;
357}
358
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359/*
360 * count() counts the number of strings in array ARGV.
361 */
362static int count(char __user * __user * argv, int max)
363{
364 int i = 0;
365
366 if (argv != NULL) {
367 for (;;) {
368 char __user * p;
369
370 if (get_user(p, argv))
371 return -EFAULT;
372 if (!p)
373 break;
374 argv++;
Jason Baron362e6662008-10-15 22:01:52 -0700375 if (i++ >= max)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 return -E2BIG;
377 cond_resched();
378 }
379 }
380 return i;
381}
382
383/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700384 * 'copy_strings()' copies argument/environment strings from the old
385 * processes's memory to the new process's stack. The call to get_user_pages()
386 * ensures the destination page is created and not swapped out.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700388static int copy_strings(int argc, char __user * __user * argv,
389 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390{
391 struct page *kmapped_page = NULL;
392 char *kaddr = NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700393 unsigned long kpos = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 int ret;
395
396 while (argc-- > 0) {
397 char __user *str;
398 int len;
399 unsigned long pos;
400
401 if (get_user(str, argv+argc) ||
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700402 !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 ret = -EFAULT;
404 goto out;
405 }
406
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700407 if (!valid_arg_len(bprm, len)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 ret = -E2BIG;
409 goto out;
410 }
411
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700412 /* We're going to work our way backwords. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 pos = bprm->p;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700414 str += len;
415 bprm->p -= len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416
417 while (len > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 int offset, bytes_to_copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419
420 offset = pos % PAGE_SIZE;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700421 if (offset == 0)
422 offset = PAGE_SIZE;
423
424 bytes_to_copy = offset;
425 if (bytes_to_copy > len)
426 bytes_to_copy = len;
427
428 offset -= bytes_to_copy;
429 pos -= bytes_to_copy;
430 str -= bytes_to_copy;
431 len -= bytes_to_copy;
432
433 if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
434 struct page *page;
435
436 page = get_arg_page(bprm, pos, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 if (!page) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700438 ret = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 goto out;
440 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700442 if (kmapped_page) {
443 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700445 put_arg_page(kmapped_page);
446 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 kmapped_page = page;
448 kaddr = kmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700449 kpos = pos & PAGE_MASK;
450 flush_arg_page(bprm, kpos, kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700452 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 ret = -EFAULT;
454 goto out;
455 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 }
457 }
458 ret = 0;
459out:
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700460 if (kmapped_page) {
461 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700463 put_arg_page(kmapped_page);
464 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 return ret;
466}
467
468/*
469 * Like copy_strings, but get argv and its values from kernel memory.
470 */
471int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
472{
473 int r;
474 mm_segment_t oldfs = get_fs();
475 set_fs(KERNEL_DS);
476 r = copy_strings(argc, (char __user * __user *)argv, bprm);
477 set_fs(oldfs);
478 return r;
479}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480EXPORT_SYMBOL(copy_strings_kernel);
481
482#ifdef CONFIG_MMU
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700483
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700485 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
486 * the binfmt code determines where the new stack should reside, we shift it to
487 * its final location. The process proceeds as follows:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 *
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700489 * 1) Use shift to calculate the new vma endpoints.
490 * 2) Extend vma to cover both the old and new ranges. This ensures the
491 * arguments passed to subsequent functions are consistent.
492 * 3) Move vma's page tables to the new range.
493 * 4) Free up any cleared pgd range.
494 * 5) Shrink the vma to cover only the new range.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700496static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497{
498 struct mm_struct *mm = vma->vm_mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700499 unsigned long old_start = vma->vm_start;
500 unsigned long old_end = vma->vm_end;
501 unsigned long length = old_end - old_start;
502 unsigned long new_start = old_start - shift;
503 unsigned long new_end = old_end - shift;
504 struct mmu_gather *tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700506 BUG_ON(new_start > new_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700508 /*
509 * ensure there are no vmas between where we want to go
510 * and where we are
511 */
512 if (vma != find_vma(mm, new_start))
513 return -EFAULT;
514
515 /*
516 * cover the whole range: [new_start, old_end)
517 */
518 vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
519
520 /*
521 * move the page tables downwards, on failure we rely on
522 * process cleanup to remove whatever mess we made.
523 */
524 if (length != move_page_tables(vma, old_start,
525 vma, new_start, length))
526 return -ENOMEM;
527
528 lru_add_drain();
529 tlb = tlb_gather_mmu(mm, 0);
530 if (new_end > old_start) {
531 /*
532 * when the old and new regions overlap clear from new_end.
533 */
Jan Beulich42b77722008-07-23 21:27:10 -0700534 free_pgd_range(tlb, new_end, old_end, new_end,
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700535 vma->vm_next ? vma->vm_next->vm_start : 0);
536 } else {
537 /*
538 * otherwise, clean from old_start; this is done to not touch
539 * the address space in [new_end, old_start) some architectures
540 * have constraints on va-space that make this illegal (IA64) -
541 * for the others its just a little faster.
542 */
Jan Beulich42b77722008-07-23 21:27:10 -0700543 free_pgd_range(tlb, old_start, old_end, new_end,
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700544 vma->vm_next ? vma->vm_next->vm_start : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700546 tlb_finish_mmu(tlb, new_end, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700548 /*
549 * shrink the vma to just the new range.
550 */
551 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
552
553 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554}
555
556#define EXTRA_STACK_VM_PAGES 20 /* random */
557
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700558/*
559 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
560 * the stack is optionally relocated, and some extra space is added.
561 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562int setup_arg_pages(struct linux_binprm *bprm,
563 unsigned long stack_top,
564 int executable_stack)
565{
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700566 unsigned long ret;
567 unsigned long stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 struct mm_struct *mm = current->mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700569 struct vm_area_struct *vma = bprm->vma;
570 struct vm_area_struct *prev = NULL;
571 unsigned long vm_flags;
572 unsigned long stack_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573
574#ifdef CONFIG_STACK_GROWSUP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 /* Limit stack size to 1GB */
576 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
577 if (stack_base > (1 << 30))
578 stack_base = 1 << 30;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700580 /* Make sure we didn't let the argument array grow too large. */
581 if (vma->vm_end - vma->vm_start > stack_base)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 return -ENOMEM;
583
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700584 stack_base = PAGE_ALIGN(stack_top - stack_base);
585
586 stack_shift = vma->vm_start - stack_base;
587 mm->arg_start = bprm->p - stack_shift;
588 bprm->p = vma->vm_end - stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589#else
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700590 stack_top = arch_align_stack(stack_top);
591 stack_top = PAGE_ALIGN(stack_top);
592 stack_shift = vma->vm_end - stack_top;
593
594 bprm->p -= stack_shift;
595 mm->arg_start = bprm->p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596#endif
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700597
598 if (bprm->loader)
599 bprm->loader -= stack_shift;
600 bprm->exec -= stack_shift;
601
602 down_write(&mm->mmap_sem);
Hugh Dickins96a8e132008-07-10 21:19:20 +0100603 vm_flags = VM_STACK_FLAGS;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700604
605 /*
606 * Adjust stack execute permissions; explicitly enable for
607 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
608 * (arch default) otherwise.
609 */
610 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
611 vm_flags |= VM_EXEC;
612 else if (executable_stack == EXSTACK_DISABLE_X)
613 vm_flags &= ~VM_EXEC;
614 vm_flags |= mm->def_flags;
615
616 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
617 vm_flags);
618 if (ret)
619 goto out_unlock;
620 BUG_ON(prev != vma);
621
622 /* Move stack pages down in memory. */
623 if (stack_shift) {
624 ret = shift_arg_pages(vma, stack_shift);
625 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 return ret;
628 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 }
630
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700631#ifdef CONFIG_STACK_GROWSUP
632 stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
633#else
634 stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
635#endif
636 ret = expand_stack(vma, stack_base);
637 if (ret)
638 ret = -EFAULT;
639
640out_unlock:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 return 0;
643}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644EXPORT_SYMBOL(setup_arg_pages);
645
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646#endif /* CONFIG_MMU */
647
648struct file *open_exec(const char *name)
649{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 struct file *file;
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200651 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652
Al Viro6e8341a2009-04-06 11:16:22 -0400653 file = do_filp_open(AT_FDCWD, name,
654 O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
655 MAY_EXEC | MAY_OPEN);
656 if (IS_ERR(file))
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200657 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200659 err = -EACCES;
Al Viro6e8341a2009-04-06 11:16:22 -0400660 if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
661 goto exit;
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200662
Al Viro6e8341a2009-04-06 11:16:22 -0400663 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
664 goto exit;
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200665
Eric Paris6110e3a2008-12-17 13:53:20 -0500666 fsnotify_open(file->f_path.dentry);
667
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200668 err = deny_write_access(file);
Al Viro6e8341a2009-04-06 11:16:22 -0400669 if (err)
670 goto exit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
Al Viro6e8341a2009-04-06 11:16:22 -0400672out:
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200673 return file;
674
Al Viro6e8341a2009-04-06 11:16:22 -0400675exit:
676 fput(file);
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200677 return ERR_PTR(err);
678}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679EXPORT_SYMBOL(open_exec);
680
Mimi Zohar6777d772009-08-21 14:32:48 -0400681int kernel_read(struct file *file, loff_t offset,
682 char *addr, unsigned long count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683{
684 mm_segment_t old_fs;
685 loff_t pos = offset;
686 int result;
687
688 old_fs = get_fs();
689 set_fs(get_ds());
690 /* The cast to a user pointer is valid due to the set_fs() */
691 result = vfs_read(file, (void __user *)addr, count, &pos);
692 set_fs(old_fs);
693 return result;
694}
695
696EXPORT_SYMBOL(kernel_read);
697
698static int exec_mmap(struct mm_struct *mm)
699{
700 struct task_struct *tsk;
701 struct mm_struct * old_mm, *active_mm;
702
703 /* Notify parent that we're no longer interested in the old VM */
704 tsk = current;
705 old_mm = current->mm;
706 mm_release(tsk, old_mm);
707
708 if (old_mm) {
709 /*
710 * Make sure that if there is a core dump in progress
711 * for the old mm, we get out and die instead of going
712 * through with the exec. We must hold mmap_sem around
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700713 * checking core_state and changing tsk->mm.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 */
715 down_read(&old_mm->mmap_sem);
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700716 if (unlikely(old_mm->core_state)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 up_read(&old_mm->mmap_sem);
718 return -EINTR;
719 }
720 }
721 task_lock(tsk);
722 active_mm = tsk->active_mm;
723 tsk->mm = mm;
724 tsk->active_mm = mm;
725 activate_mm(active_mm, mm);
726 task_unlock(tsk);
727 arch_pick_mmap_layout(mm);
728 if (old_mm) {
729 up_read(&old_mm->mmap_sem);
Eric Sesterhenn7dddb122006-04-01 01:13:38 +0200730 BUG_ON(active_mm != old_mm);
Balbir Singh31a78f22008-09-28 23:09:31 +0100731 mm_update_next_owner(old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 mmput(old_mm);
733 return 0;
734 }
735 mmdrop(active_mm);
736 return 0;
737}
738
739/*
740 * This function makes sure the current process has its own signal table,
741 * so that flush_signal_handlers can later reset the handlers without
742 * disturbing other processes. (Other processes might share the signal
743 * table via the CLONE_SIGHAND option to clone().)
744 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800745static int de_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746{
747 struct signal_struct *sig = tsk->signal;
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700748 struct sighand_struct *oldsighand = tsk->sighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 spinlock_t *lock = &oldsighand->siglock;
750 int count;
751
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700752 if (thread_group_empty(tsk))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 goto no_thread_group;
754
755 /*
756 * Kill all other threads in the thread group.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 spin_lock_irq(lock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800759 if (signal_group_exit(sig)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 /*
761 * Another group action in progress, just
762 * return so that the signal is processed.
763 */
764 spin_unlock_irq(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 return -EAGAIN;
766 }
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800767 sig->group_exit_task = tsk;
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700768 zap_other_threads(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769
Oleg Nesterovfea9d172008-02-08 04:19:19 -0800770 /* Account for the thread group leader hanging around: */
771 count = thread_group_leader(tsk) ? 1 : 2;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700772 sig->notify_count = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 while (atomic_read(&sig->count) > count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 __set_current_state(TASK_UNINTERRUPTIBLE);
775 spin_unlock_irq(lock);
776 schedule();
777 spin_lock_irq(lock);
778 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 spin_unlock_irq(lock);
780
781 /*
782 * At this point all other threads have exited, all we have to
783 * do is to wait for the thread group leader to become inactive,
784 * and to assume its PID:
785 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700786 if (!thread_group_leader(tsk)) {
Oleg Nesterov81879262008-12-01 14:18:16 -0800787 struct task_struct *leader = tsk->group_leader;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700788
Oleg Nesterov2800d8d2008-04-30 00:53:12 -0700789 sig->notify_count = -1; /* for exit_notify() */
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700790 for (;;) {
791 write_lock_irq(&tasklist_lock);
792 if (likely(leader->exit_state))
793 break;
794 __set_current_state(TASK_UNINTERRUPTIBLE);
795 write_unlock_irq(&tasklist_lock);
796 schedule();
797 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
Roland McGrathf5e90282006-04-10 22:54:16 -0700799 /*
800 * The only record we have of the real-time age of a
801 * process, regardless of execs it's done, is start_time.
802 * All the past CPU time is accumulated in signal_struct
803 * from sister threads now dead. But in this non-leader
804 * exec, nothing survives from the original leader thread,
805 * whose birth marks the true age of this process now.
806 * When we take on its identity by switching to its PID, we
807 * also take its birthdate (always earlier than our own).
808 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700809 tsk->start_time = leader->start_time;
Roland McGrathf5e90282006-04-10 22:54:16 -0700810
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700811 BUG_ON(!same_thread_group(leader, tsk));
812 BUG_ON(has_group_leader_pid(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 /*
814 * An exec() starts a new thread group with the
815 * TGID of the previous thread group. Rehash the
816 * two threads with a switched PID, and release
817 * the former thread group leader:
818 */
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800819
820 /* Become a process group leader with the old leader's pid.
Eric W. Biedermanc18258c2006-09-27 01:51:06 -0700821 * The old leader becomes a thread of the this thread group.
822 * Note: The old leader also uses this pid until release_task
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800823 * is called. Odd but simple and correct.
824 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700825 detach_pid(tsk, PIDTYPE_PID);
826 tsk->pid = leader->pid;
Sukadev Bhattiprolu3743ca02007-10-18 23:39:51 -0700827 attach_pid(tsk, PIDTYPE_PID, task_pid(leader));
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700828 transfer_pid(leader, tsk, PIDTYPE_PGID);
829 transfer_pid(leader, tsk, PIDTYPE_SID);
830 list_replace_rcu(&leader->tasks, &tsk->tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700832 tsk->group_leader = tsk;
833 leader->group_leader = tsk;
Eric W. Biedermande12a782006-04-10 17:16:49 -0600834
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700835 tsk->exit_signal = SIGCHLD;
Oleg Nesterov962b5642005-11-23 13:37:43 -0800836
837 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
838 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 write_unlock_irq(&tasklist_lock);
Oleg Nesterov81879262008-12-01 14:18:16 -0800840
841 release_task(leader);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800842 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700844 sig->group_exit_task = NULL;
845 sig->notify_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
847no_thread_group:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 exit_itimers(sig);
Oleg Nesterovcbaffba2008-05-26 20:55:42 +0400849 flush_itimer_signals();
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300850
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700851 if (atomic_read(&oldsighand->count) != 1) {
852 struct sighand_struct *newsighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 /*
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700854 * This ->sighand is shared with the CLONE_SIGHAND
855 * but not CLONE_THREAD task, switch to the new one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 */
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700857 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
858 if (!newsighand)
859 return -ENOMEM;
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 atomic_set(&newsighand->count, 1);
862 memcpy(newsighand->action, oldsighand->action,
863 sizeof(newsighand->action));
864
865 write_lock_irq(&tasklist_lock);
866 spin_lock(&oldsighand->siglock);
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700867 rcu_assign_pointer(tsk->sighand, newsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 spin_unlock(&oldsighand->siglock);
869 write_unlock_irq(&tasklist_lock);
870
Davide Libenzifba2afa2007-05-10 22:23:13 -0700871 __cleanup_sighand(oldsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 }
873
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700874 BUG_ON(!thread_group_leader(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 return 0;
876}
Oleg Nesterov0840a902007-10-16 23:27:22 -0700877
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878/*
879 * These functions flushes out all traces of the currently running executable
880 * so that a new one can be started
881 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800882static void flush_old_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883{
884 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700885 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886
887 spin_lock(&files->file_lock);
888 for (;;) {
889 unsigned long set, i;
890
891 j++;
892 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700893 fdt = files_fdtable(files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800894 if (i >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700896 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 if (!set)
898 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700899 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 spin_unlock(&files->file_lock);
901 for ( ; set ; i++,set >>= 1) {
902 if (set & 1) {
903 sys_close(i);
904 }
905 }
906 spin_lock(&files->file_lock);
907
908 }
909 spin_unlock(&files->file_lock);
910}
911
Andrew Morton59714d62008-02-04 22:27:21 -0800912char *get_task_comm(char *buf, struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913{
914 /* buf must be at least sizeof(tsk->comm) in size */
915 task_lock(tsk);
916 strncpy(buf, tsk->comm, sizeof(tsk->comm));
917 task_unlock(tsk);
Andrew Morton59714d62008-02-04 22:27:21 -0800918 return buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919}
920
921void set_task_comm(struct task_struct *tsk, char *buf)
922{
923 task_lock(tsk);
924 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
925 task_unlock(tsk);
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200926 perf_event_comm(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927}
928
929int flush_old_exec(struct linux_binprm * bprm)
930{
931 char * name;
932 int i, ch, retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 char tcomm[sizeof(current->comm)];
934
935 /*
936 * Make sure we have a private signal table and that
937 * we are unassociated from the previous thread group.
938 */
939 retval = de_thread(current);
940 if (retval)
941 goto out;
942
Matt Helsley925d1c42008-04-29 01:01:36 -0700943 set_mm_exe_file(bprm->mm, bprm->file);
944
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 * Release all of the old mmap stuff
947 */
948 retval = exec_mmap(bprm->mm);
949 if (retval)
Al Virofd8328b2008-04-22 05:11:59 -0400950 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951
952 bprm->mm = NULL; /* We're using it now */
953
954 /* This is the point of no return */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 current->sas_ss_sp = current->sas_ss_size = 0;
956
David Howellsda9592e2008-11-14 10:39:05 +1100957 if (current_euid() == current_uid() && current_egid() == current_gid())
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700958 set_dumpable(current->mm, 1);
Alan Coxd6e71142005-06-23 00:09:43 -0700959 else
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700960 set_dumpable(current->mm, suid_dumpable);
Alan Coxd6e71142005-06-23 00:09:43 -0700961
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700963
964 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 for (i=0; (ch = *(name++)) != '\0';) {
966 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700967 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 else
969 if (i < (sizeof(tcomm) - 1))
970 tcomm[i++] = ch;
971 }
972 tcomm[i] = '\0';
973 set_task_comm(current, tcomm);
974
975 current->flags &= ~PF_RANDOMIZE;
976 flush_thread();
977
Benjamin Herrenschmidt0551fbd2006-02-28 16:59:19 -0800978 /* Set the new mm task size. We have to do that late because it may
979 * depend on TIF_32BIT which is only updated in flush_thread() on
980 * some architectures like powerpc
981 */
982 current->mm->task_size = TASK_SIZE;
983
David Howellsa6f76f22008-11-14 10:39:24 +1100984 /* install the new credentials */
985 if (bprm->cred->uid != current_euid() ||
986 bprm->cred->gid != current_egid()) {
Marcel Holtmannd2d56c52007-08-17 21:47:58 +0200987 current->pdeath_signal = 0;
988 } else if (file_permission(bprm->file, MAY_READ) ||
David Howellsa6f76f22008-11-14 10:39:24 +1100989 bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) {
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700990 set_dumpable(current->mm, suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 }
992
David Howellsa6f76f22008-11-14 10:39:24 +1100993 current->personality &= ~bprm->per_clear;
994
Ingo Molnarf65cb452008-12-16 13:40:44 +0100995 /*
996 * Flush performance counters when crossing a
997 * security domain:
998 */
999 if (!get_dumpable(current->mm))
Ingo Molnarcdd6c482009-09-21 12:02:48 +02001000 perf_event_exit_task(current);
Ingo Molnarf65cb452008-12-16 13:40:44 +01001001
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 /* An exec changes our domain. We are no longer part of the thread
1003 group */
1004
1005 current->self_exec_id++;
1006
1007 flush_signal_handlers(current, 0);
1008 flush_old_files(current->files);
1009
1010 return 0;
1011
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012out:
1013 return retval;
1014}
1015
1016EXPORT_SYMBOL(flush_old_exec);
1017
David Howellsa6f76f22008-11-14 10:39:24 +11001018/*
Oleg Nesterova2a84742009-09-05 11:17:13 -07001019 * Prepare credentials and lock ->cred_guard_mutex.
1020 * install_exec_creds() commits the new creds and drops the lock.
1021 * Or, if exec fails before, free_bprm() should release ->cred and
1022 * and unlock.
1023 */
1024int prepare_bprm_creds(struct linux_binprm *bprm)
1025{
1026 if (mutex_lock_interruptible(&current->cred_guard_mutex))
1027 return -ERESTARTNOINTR;
1028
1029 bprm->cred = prepare_exec_creds();
1030 if (likely(bprm->cred))
1031 return 0;
1032
1033 mutex_unlock(&current->cred_guard_mutex);
1034 return -ENOMEM;
1035}
1036
1037void free_bprm(struct linux_binprm *bprm)
1038{
1039 free_arg_pages(bprm);
1040 if (bprm->cred) {
1041 mutex_unlock(&current->cred_guard_mutex);
1042 abort_creds(bprm->cred);
1043 }
1044 kfree(bprm);
1045}
1046
1047/*
David Howellsa6f76f22008-11-14 10:39:24 +11001048 * install the new credentials for this executable
1049 */
1050void install_exec_creds(struct linux_binprm *bprm)
1051{
1052 security_bprm_committing_creds(bprm);
1053
1054 commit_creds(bprm->cred);
1055 bprm->cred = NULL;
Oleg Nesterova2a84742009-09-05 11:17:13 -07001056 /*
1057 * cred_guard_mutex must be held at least to this point to prevent
David Howellsa6f76f22008-11-14 10:39:24 +11001058 * ptrace_attach() from altering our determination of the task's
Oleg Nesterova2a84742009-09-05 11:17:13 -07001059 * credentials; any time after this it may be unlocked.
1060 */
David Howellsa6f76f22008-11-14 10:39:24 +11001061 security_bprm_committed_creds(bprm);
Oleg Nesterova2a84742009-09-05 11:17:13 -07001062 mutex_unlock(&current->cred_guard_mutex);
David Howellsa6f76f22008-11-14 10:39:24 +11001063}
1064EXPORT_SYMBOL(install_exec_creds);
1065
1066/*
1067 * determine how safe it is to execute the proposed program
David Howells5e751e92009-05-08 13:55:22 +01001068 * - the caller must hold current->cred_guard_mutex to protect against
David Howellsa6f76f22008-11-14 10:39:24 +11001069 * PTRACE_ATTACH
1070 */
Al Viro498052b2009-03-30 07:20:30 -04001071int check_unsafe_exec(struct linux_binprm *bprm)
David Howellsa6f76f22008-11-14 10:39:24 +11001072{
David Howells0bf2f3a2009-02-06 11:45:46 +00001073 struct task_struct *p = current, *t;
Al Virof1191b52009-03-30 07:35:18 -04001074 unsigned n_fs;
Al Viro498052b2009-03-30 07:20:30 -04001075 int res = 0;
David Howellsa6f76f22008-11-14 10:39:24 +11001076
1077 bprm->unsafe = tracehook_unsafe_exec(p);
1078
David Howells0bf2f3a2009-02-06 11:45:46 +00001079 n_fs = 1;
Al Viro498052b2009-03-30 07:20:30 -04001080 write_lock(&p->fs->lock);
Oleg Nesterov437f7fd2009-04-24 01:02:45 +02001081 rcu_read_lock();
David Howells0bf2f3a2009-02-06 11:45:46 +00001082 for (t = next_thread(p); t != p; t = next_thread(t)) {
1083 if (t->fs == p->fs)
1084 n_fs++;
David Howells0bf2f3a2009-02-06 11:45:46 +00001085 }
Oleg Nesterov437f7fd2009-04-24 01:02:45 +02001086 rcu_read_unlock();
David Howells0bf2f3a2009-02-06 11:45:46 +00001087
Al Virof1191b52009-03-30 07:35:18 -04001088 if (p->fs->users > n_fs) {
David Howellsa6f76f22008-11-14 10:39:24 +11001089 bprm->unsafe |= LSM_UNSAFE_SHARE;
Al Viro498052b2009-03-30 07:20:30 -04001090 } else {
Oleg Nesterov8c652f92009-04-24 01:01:56 +02001091 res = -EAGAIN;
1092 if (!p->fs->in_exec) {
1093 p->fs->in_exec = 1;
1094 res = 1;
1095 }
Al Viro498052b2009-03-30 07:20:30 -04001096 }
Al Viro498052b2009-03-30 07:20:30 -04001097 write_unlock(&p->fs->lock);
1098
1099 return res;
David Howellsa6f76f22008-11-14 10:39:24 +11001100}
1101
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102/*
1103 * Fill the binprm structure from the inode.
1104 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
David Howellsa6f76f22008-11-14 10:39:24 +11001105 *
1106 * This may be called multiple times for binary chains (scripts for example).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 */
1108int prepare_binprm(struct linux_binprm *bprm)
1109{
David Howellsa6f76f22008-11-14 10:39:24 +11001110 umode_t mode;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001111 struct inode * inode = bprm->file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 int retval;
1113
1114 mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 if (bprm->file->f_op == NULL)
1116 return -EACCES;
1117
David Howellsa6f76f22008-11-14 10:39:24 +11001118 /* clear any previous set[ug]id data from a previous binary */
1119 bprm->cred->euid = current_euid();
1120 bprm->cred->egid = current_egid();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121
David Howellsa6f76f22008-11-14 10:39:24 +11001122 if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 /* Set-uid? */
1124 if (mode & S_ISUID) {
David Howellsa6f76f22008-11-14 10:39:24 +11001125 bprm->per_clear |= PER_CLEAR_ON_SETID;
1126 bprm->cred->euid = inode->i_uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 }
1128
1129 /* Set-gid? */
1130 /*
1131 * If setgid is set but no group execute bit then this
1132 * is a candidate for mandatory locking, not a setgid
1133 * executable.
1134 */
1135 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
David Howellsa6f76f22008-11-14 10:39:24 +11001136 bprm->per_clear |= PER_CLEAR_ON_SETID;
1137 bprm->cred->egid = inode->i_gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 }
1139 }
1140
1141 /* fill in binprm security blob */
David Howellsa6f76f22008-11-14 10:39:24 +11001142 retval = security_bprm_set_creds(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 if (retval)
1144 return retval;
David Howellsa6f76f22008-11-14 10:39:24 +11001145 bprm->cred_prepared = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146
David Howellsa6f76f22008-11-14 10:39:24 +11001147 memset(bprm->buf, 0, BINPRM_BUF_SIZE);
1148 return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149}
1150
1151EXPORT_SYMBOL(prepare_binprm);
1152
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001153/*
1154 * Arguments are '\0' separated strings found at the location bprm->p
1155 * points to; chop off the first by relocating brpm->p to right after
1156 * the first '\0' encountered.
1157 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001158int remove_arg_zero(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159{
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001160 int ret = 0;
1161 unsigned long offset;
1162 char *kaddr;
1163 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001165 if (!bprm->argc)
1166 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001168 do {
1169 offset = bprm->p & ~PAGE_MASK;
1170 page = get_arg_page(bprm, bprm->p, 0);
1171 if (!page) {
1172 ret = -EFAULT;
1173 goto out;
1174 }
1175 kaddr = kmap_atomic(page, KM_USER0);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001176
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001177 for (; offset < PAGE_SIZE && kaddr[offset];
1178 offset++, bprm->p++)
1179 ;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001180
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001181 kunmap_atomic(kaddr, KM_USER0);
1182 put_arg_page(page);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001183
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001184 if (offset == PAGE_SIZE)
1185 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
1186 } while (offset == PAGE_SIZE);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001187
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001188 bprm->p++;
1189 bprm->argc--;
1190 ret = 0;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001191
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001192out:
1193 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195EXPORT_SYMBOL(remove_arg_zero);
1196
1197/*
1198 * cycle the list of binary formats handler, until one recognizes the image
1199 */
1200int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1201{
Roland McGrath85f33462008-12-09 19:36:38 -08001202 unsigned int depth = bprm->recursion_depth;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 int try,retval;
1204 struct linux_binfmt *fmt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 retval = security_bprm_check(bprm);
1207 if (retval)
1208 return retval;
Mimi Zohar6146f0d2009-02-04 09:06:57 -05001209 retval = ima_bprm_check(bprm);
1210 if (retval)
1211 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212
1213 /* kernel module loader fixup */
1214 /* so we don't try to load run modprobe in kernel space. */
1215 set_fs(USER_DS);
Al Viro473ae302006-04-26 14:04:08 -04001216
1217 retval = audit_bprm(bprm);
1218 if (retval)
1219 return retval;
1220
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 retval = -ENOENT;
1222 for (try=0; try<2; try++) {
1223 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -07001224 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1226 if (!fn)
1227 continue;
1228 if (!try_module_get(fmt->module))
1229 continue;
1230 read_unlock(&binfmt_lock);
1231 retval = fn(bprm, regs);
Roland McGrath85f33462008-12-09 19:36:38 -08001232 /*
1233 * Restore the depth counter to its starting value
1234 * in this call, so we don't have to rely on every
1235 * load_binary function to restore it on return.
1236 */
1237 bprm->recursion_depth = depth;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238 if (retval >= 0) {
Roland McGrath85f33462008-12-09 19:36:38 -08001239 if (depth == 0)
1240 tracehook_report_exec(fmt, bprm, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 put_binfmt(fmt);
1242 allow_write_access(bprm->file);
1243 if (bprm->file)
1244 fput(bprm->file);
1245 bprm->file = NULL;
1246 current->did_exec = 1;
Matt Helsley9f460802005-11-07 00:59:16 -08001247 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 return retval;
1249 }
1250 read_lock(&binfmt_lock);
1251 put_binfmt(fmt);
1252 if (retval != -ENOEXEC || bprm->mm == NULL)
1253 break;
1254 if (!bprm->file) {
1255 read_unlock(&binfmt_lock);
1256 return retval;
1257 }
1258 }
1259 read_unlock(&binfmt_lock);
1260 if (retval != -ENOEXEC || bprm->mm == NULL) {
1261 break;
Johannes Berg5f4123b2008-07-09 10:28:40 +02001262#ifdef CONFIG_MODULES
1263 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1265 if (printable(bprm->buf[0]) &&
1266 printable(bprm->buf[1]) &&
1267 printable(bprm->buf[2]) &&
1268 printable(bprm->buf[3]))
1269 break; /* -ENOEXEC */
1270 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1271#endif
1272 }
1273 }
1274 return retval;
1275}
1276
1277EXPORT_SYMBOL(search_binary_handler);
1278
1279/*
1280 * sys_execve() executes a new program.
1281 */
1282int do_execve(char * filename,
1283 char __user *__user *argv,
1284 char __user *__user *envp,
1285 struct pt_regs * regs)
1286{
1287 struct linux_binprm *bprm;
1288 struct file *file;
Al Viro3b125382008-04-22 05:31:30 -04001289 struct files_struct *displaced;
Oleg Nesterov8c652f92009-04-24 01:01:56 +02001290 bool clear_in_exec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292
Al Viro3b125382008-04-22 05:31:30 -04001293 retval = unshare_files(&displaced);
Al Virofd8328b2008-04-22 05:11:59 -04001294 if (retval)
1295 goto out_ret;
1296
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 retval = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001298 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 if (!bprm)
Al Virofd8328b2008-04-22 05:11:59 -04001300 goto out_files;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301
Oleg Nesterova2a84742009-09-05 11:17:13 -07001302 retval = prepare_bprm_creds(bprm);
1303 if (retval)
David Howellsa6f76f22008-11-14 10:39:24 +11001304 goto out_free;
Al Viro498052b2009-03-30 07:20:30 -04001305
1306 retval = check_unsafe_exec(bprm);
Oleg Nesterov8c652f92009-04-24 01:01:56 +02001307 if (retval < 0)
Oleg Nesterova2a84742009-09-05 11:17:13 -07001308 goto out_free;
Oleg Nesterov8c652f92009-04-24 01:01:56 +02001309 clear_in_exec = retval;
Oleg Nesterova2a84742009-09-05 11:17:13 -07001310 current->in_execve = 1;
David Howellsa6f76f22008-11-14 10:39:24 +11001311
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 file = open_exec(filename);
1313 retval = PTR_ERR(file);
1314 if (IS_ERR(file))
Al Viro498052b2009-03-30 07:20:30 -04001315 goto out_unmark;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
1317 sched_exec();
1318
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 bprm->file = file;
1320 bprm->filename = filename;
1321 bprm->interp = filename;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001322
1323 retval = bprm_mm_init(bprm);
1324 if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 goto out_file;
1326
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001327 bprm->argc = count(argv, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 if ((retval = bprm->argc) < 0)
David Howellsa6f76f22008-11-14 10:39:24 +11001329 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001331 bprm->envc = count(envp, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 if ((retval = bprm->envc) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 goto out;
1334
1335 retval = prepare_binprm(bprm);
1336 if (retval < 0)
1337 goto out;
1338
1339 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1340 if (retval < 0)
1341 goto out;
1342
1343 bprm->exec = bprm->p;
1344 retval = copy_strings(bprm->envc, envp, bprm);
1345 if (retval < 0)
1346 goto out;
1347
1348 retval = copy_strings(bprm->argc, argv, bprm);
1349 if (retval < 0)
1350 goto out;
1351
Oleg Nesterov7b34e422008-07-25 01:47:37 -07001352 current->flags &= ~PF_KTHREAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 retval = search_binary_handler(bprm,regs);
David Howellsa6f76f22008-11-14 10:39:24 +11001354 if (retval < 0)
1355 goto out;
1356
1357 /* execve succeeded */
Al Viro498052b2009-03-30 07:20:30 -04001358 current->fs->in_exec = 0;
Kentaro Takedaf9ce1f12009-02-05 17:18:11 +09001359 current->in_execve = 0;
David Howellsa6f76f22008-11-14 10:39:24 +11001360 acct_update_integrals(current);
1361 free_bprm(bprm);
1362 if (displaced)
1363 put_files_struct(displaced);
1364 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365
1366out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 if (bprm->mm)
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001368 mmput (bprm->mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369
1370out_file:
1371 if (bprm->file) {
1372 allow_write_access(bprm->file);
1373 fput(bprm->file);
1374 }
David Howellsa6f76f22008-11-14 10:39:24 +11001375
Al Viro498052b2009-03-30 07:20:30 -04001376out_unmark:
Oleg Nesterov8c652f92009-04-24 01:01:56 +02001377 if (clear_in_exec)
1378 current->fs->in_exec = 0;
Kentaro Takedaf9ce1f12009-02-05 17:18:11 +09001379 current->in_execve = 0;
David Howellsa6f76f22008-11-14 10:39:24 +11001380
1381out_free:
Al Viro08a6fac2008-05-10 16:38:25 -04001382 free_bprm(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383
Al Virofd8328b2008-04-22 05:11:59 -04001384out_files:
Al Viro3b125382008-04-22 05:31:30 -04001385 if (displaced)
1386 reset_files_struct(displaced);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387out_ret:
1388 return retval;
1389}
1390
1391int set_binfmt(struct linux_binfmt *new)
1392{
1393 struct linux_binfmt *old = current->binfmt;
1394
1395 if (new) {
1396 if (!try_module_get(new->module))
1397 return -1;
1398 }
1399 current->binfmt = new;
1400 if (old)
1401 module_put(old->module);
1402 return 0;
1403}
1404
1405EXPORT_SYMBOL(set_binfmt);
1406
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407/* format_corename will inspect the pattern parameter, and output a
1408 * name into corename, which must have space for at least
1409 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1410 */
Oleg Nesterov64093242008-10-18 20:28:22 -07001411static int format_corename(char *corename, long signr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412{
David Howells86a264a2008-11-14 10:39:18 +11001413 const struct cred *cred = current_cred();
Oleg Nesterov565b9b12008-07-25 01:47:47 -07001414 const char *pat_ptr = core_pattern;
1415 int ispipe = (*pat_ptr == '|');
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 char *out_ptr = corename;
1417 char *const out_end = corename + CORENAME_MAX_SIZE;
1418 int rc;
1419 int pid_in_pattern = 0;
1420
1421 /* Repeat as long as we have more pattern to process and more output
1422 space */
1423 while (*pat_ptr) {
1424 if (*pat_ptr != '%') {
1425 if (out_ptr == out_end)
1426 goto out;
1427 *out_ptr++ = *pat_ptr++;
1428 } else {
1429 switch (*++pat_ptr) {
1430 case 0:
1431 goto out;
1432 /* Double percent, output one percent */
1433 case '%':
1434 if (out_ptr == out_end)
1435 goto out;
1436 *out_ptr++ = '%';
1437 break;
1438 /* pid */
1439 case 'p':
1440 pid_in_pattern = 1;
1441 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001442 "%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 if (rc > out_end - out_ptr)
1444 goto out;
1445 out_ptr += rc;
1446 break;
1447 /* uid */
1448 case 'u':
1449 rc = snprintf(out_ptr, out_end - out_ptr,
David Howells86a264a2008-11-14 10:39:18 +11001450 "%d", cred->uid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451 if (rc > out_end - out_ptr)
1452 goto out;
1453 out_ptr += rc;
1454 break;
1455 /* gid */
1456 case 'g':
1457 rc = snprintf(out_ptr, out_end - out_ptr,
David Howells86a264a2008-11-14 10:39:18 +11001458 "%d", cred->gid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 if (rc > out_end - out_ptr)
1460 goto out;
1461 out_ptr += rc;
1462 break;
1463 /* signal that caused the coredump */
1464 case 's':
1465 rc = snprintf(out_ptr, out_end - out_ptr,
1466 "%ld", signr);
1467 if (rc > out_end - out_ptr)
1468 goto out;
1469 out_ptr += rc;
1470 break;
1471 /* UNIX time of coredump */
1472 case 't': {
1473 struct timeval tv;
1474 do_gettimeofday(&tv);
1475 rc = snprintf(out_ptr, out_end - out_ptr,
1476 "%lu", tv.tv_sec);
1477 if (rc > out_end - out_ptr)
1478 goto out;
1479 out_ptr += rc;
1480 break;
1481 }
1482 /* hostname */
1483 case 'h':
1484 down_read(&uts_sem);
1485 rc = snprintf(out_ptr, out_end - out_ptr,
Serge E. Hallyne9ff3992006-10-02 02:18:11 -07001486 "%s", utsname()->nodename);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 up_read(&uts_sem);
1488 if (rc > out_end - out_ptr)
1489 goto out;
1490 out_ptr += rc;
1491 break;
1492 /* executable */
1493 case 'e':
1494 rc = snprintf(out_ptr, out_end - out_ptr,
1495 "%s", current->comm);
1496 if (rc > out_end - out_ptr)
1497 goto out;
1498 out_ptr += rc;
1499 break;
Neil Horman74aadce2007-10-16 23:26:35 -07001500 /* core limit size */
1501 case 'c':
1502 rc = snprintf(out_ptr, out_end - out_ptr,
1503 "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
1504 if (rc > out_end - out_ptr)
1505 goto out;
1506 out_ptr += rc;
1507 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 default:
1509 break;
1510 }
1511 ++pat_ptr;
1512 }
1513 }
1514 /* Backward compatibility with core_uses_pid:
1515 *
1516 * If core_pattern does not include a %p (as is the default)
1517 * and core_uses_pid is set, then .%pid will be appended to
Alan Coxc4bbafd2007-04-16 22:53:13 -07001518 * the filename. Do not do this for piped commands. */
Oleg Nesterov64093242008-10-18 20:28:22 -07001519 if (!ispipe && !pid_in_pattern && core_uses_pid) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001521 ".%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 if (rc > out_end - out_ptr)
1523 goto out;
1524 out_ptr += rc;
1525 }
Alan Coxc4bbafd2007-04-16 22:53:13 -07001526out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 *out_ptr = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001528 return ispipe;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529}
1530
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001531static int zap_process(struct task_struct *start)
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001532{
1533 struct task_struct *t;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001534 int nr = 0;
Oleg Nesterov281de332006-06-26 00:26:06 -07001535
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001536 start->signal->flags = SIGNAL_GROUP_EXIT;
1537 start->signal->group_stop_count = 0;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001538
1539 t = start;
1540 do {
1541 if (t != current && t->mm) {
Oleg Nesterov281de332006-06-26 00:26:06 -07001542 sigaddset(&t->pending.signal, SIGKILL);
1543 signal_wake_up(t, 1);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001544 nr++;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001545 }
Oleg Nesterove4901f92008-07-25 01:47:31 -07001546 } while_each_thread(start, t);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001547
1548 return nr;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001549}
1550
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001551static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001552 struct core_state *core_state, int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553{
1554 struct task_struct *g, *p;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001555 unsigned long flags;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001556 int nr = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001558 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001559 if (!signal_group_exit(tsk->signal)) {
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001560 mm->core_state = core_state;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001561 tsk->signal->group_exit_code = exit_code;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001562 nr = zap_process(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563 }
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001564 spin_unlock_irq(&tsk->sighand->siglock);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001565 if (unlikely(nr < 0))
1566 return nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001568 if (atomic_read(&mm->mm_users) == nr + 1)
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001569 goto done;
Oleg Nesterove4901f92008-07-25 01:47:31 -07001570 /*
1571 * We should find and kill all tasks which use this mm, and we should
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001572 * count them correctly into ->nr_threads. We don't take tasklist
Oleg Nesterove4901f92008-07-25 01:47:31 -07001573 * lock, but this is safe wrt:
1574 *
1575 * fork:
1576 * None of sub-threads can fork after zap_process(leader). All
1577 * processes which were created before this point should be
1578 * visible to zap_threads() because copy_process() adds the new
1579 * process to the tail of init_task.tasks list, and lock/unlock
1580 * of ->siglock provides a memory barrier.
1581 *
1582 * do_exit:
1583 * The caller holds mm->mmap_sem. This means that the task which
1584 * uses this mm can't pass exit_mm(), so it can't exit or clear
1585 * its ->mm.
1586 *
1587 * de_thread:
1588 * It does list_replace_rcu(&leader->tasks, &current->tasks),
1589 * we must see either old or new leader, this does not matter.
1590 * However, it can change p->sighand, so lock_task_sighand(p)
1591 * must be used. Since p->mm != NULL and we hold ->mmap_sem
1592 * it can't fail.
1593 *
1594 * Note also that "g" can be the old leader with ->mm == NULL
1595 * and already unhashed and thus removed from ->thread_group.
1596 * This is OK, __unhash_process()->list_del_rcu() does not
1597 * clear the ->next pointer, we will find the new leader via
1598 * next_thread().
1599 */
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001600 rcu_read_lock();
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001601 for_each_process(g) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001602 if (g == tsk->group_leader)
1603 continue;
Oleg Nesterov15b9f362008-07-25 01:47:39 -07001604 if (g->flags & PF_KTHREAD)
1605 continue;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001606 p = g;
1607 do {
1608 if (p->mm) {
Oleg Nesterov15b9f362008-07-25 01:47:39 -07001609 if (unlikely(p->mm == mm)) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001610 lock_task_sighand(p, &flags);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001611 nr += zap_process(p);
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001612 unlock_task_sighand(p, &flags);
1613 }
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001614 break;
1615 }
Oleg Nesterove4901f92008-07-25 01:47:31 -07001616 } while_each_thread(g, p);
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001617 }
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001618 rcu_read_unlock();
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001619done:
Oleg Nesterovc5f1cc82008-07-25 01:47:42 -07001620 atomic_set(&core_state->nr_threads, nr);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001621 return nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001622}
1623
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001624static int coredump_wait(int exit_code, struct core_state *core_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625{
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001626 struct task_struct *tsk = current;
1627 struct mm_struct *mm = tsk->mm;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001628 struct completion *vfork_done;
Oleg Nesterov2384f552005-10-30 15:02:47 -08001629 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001631 init_completion(&core_state->startup);
Oleg Nesterovb564daf2008-07-25 01:47:44 -07001632 core_state->dumper.task = tsk;
1633 core_state->dumper.next = NULL;
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001634 core_waiters = zap_threads(tsk, mm, core_state, exit_code);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001635 up_write(&mm->mmap_sem);
1636
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001637 if (unlikely(core_waiters < 0))
1638 goto fail;
1639
1640 /*
1641 * Make sure nobody is waiting for us to release the VM,
1642 * otherwise we can deadlock when we wait on each other
1643 */
1644 vfork_done = tsk->vfork_done;
1645 if (vfork_done) {
1646 tsk->vfork_done = NULL;
1647 complete(vfork_done);
1648 }
1649
Oleg Nesterov2384f552005-10-30 15:02:47 -08001650 if (core_waiters)
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001651 wait_for_completion(&core_state->startup);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001652fail:
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001653 return core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654}
1655
Oleg Nesterova94e2d42008-07-25 01:47:46 -07001656static void coredump_finish(struct mm_struct *mm)
1657{
1658 struct core_thread *curr, *next;
1659 struct task_struct *task;
1660
1661 next = mm->core_state->dumper.next;
1662 while ((curr = next) != NULL) {
1663 next = curr->next;
1664 task = curr->task;
1665 /*
1666 * see exit_mm(), curr->task must not see
1667 * ->task == NULL before we read ->next.
1668 */
1669 smp_mb();
1670 curr->task = NULL;
1671 wake_up_process(task);
1672 }
1673
1674 mm->core_state = NULL;
1675}
1676
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001677/*
1678 * set_dumpable converts traditional three-value dumpable to two flags and
1679 * stores them into mm->flags. It modifies lower two bits of mm->flags, but
1680 * these bits are not changed atomically. So get_dumpable can observe the
1681 * intermediate state. To avoid doing unexpected behavior, get get_dumpable
1682 * return either old dumpable or new one by paying attention to the order of
1683 * modifying the bits.
1684 *
1685 * dumpable | mm->flags (binary)
1686 * old new | initial interim final
1687 * ---------+-----------------------
1688 * 0 1 | 00 01 01
1689 * 0 2 | 00 10(*) 11
1690 * 1 0 | 01 00 00
1691 * 1 2 | 01 11 11
1692 * 2 0 | 11 10(*) 00
1693 * 2 1 | 11 11 01
1694 *
1695 * (*) get_dumpable regards interim value of 10 as 11.
1696 */
1697void set_dumpable(struct mm_struct *mm, int value)
1698{
1699 switch (value) {
1700 case 0:
1701 clear_bit(MMF_DUMPABLE, &mm->flags);
1702 smp_wmb();
1703 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1704 break;
1705 case 1:
1706 set_bit(MMF_DUMPABLE, &mm->flags);
1707 smp_wmb();
1708 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1709 break;
1710 case 2:
1711 set_bit(MMF_DUMP_SECURELY, &mm->flags);
1712 smp_wmb();
1713 set_bit(MMF_DUMPABLE, &mm->flags);
1714 break;
1715 }
1716}
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001717
1718int get_dumpable(struct mm_struct *mm)
1719{
1720 int ret;
1721
1722 ret = mm->flags & 0x3;
1723 return (ret >= 2) ? 2 : ret;
1724}
1725
WANG Cong8cd3ac32009-01-06 14:42:48 -08001726void do_coredump(long signr, int exit_code, struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727{
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001728 struct core_state core_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 char corename[CORENAME_MAX_SIZE + 1];
1730 struct mm_struct *mm = current->mm;
1731 struct linux_binfmt * binfmt;
1732 struct inode * inode;
1733 struct file * file;
David Howellsd84f4f92008-11-14 10:39:23 +11001734 const struct cred *old_cred;
1735 struct cred *cred;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001737 int flag = 0;
Andi Kleend025c9d2006-09-30 23:29:28 -07001738 int ispipe = 0;
Neil Horman7dc0b222007-10-16 23:26:34 -07001739 unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
Neil Horman74aadce2007-10-16 23:26:35 -07001740 char **helper_argv = NULL;
1741 int helper_argc = 0;
1742 char *delimit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743
Steve Grubb0a4ff8c2007-04-19 10:28:21 -04001744 audit_core_dumps(signr);
1745
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 binfmt = current->binfmt;
1747 if (!binfmt || !binfmt->core_dump)
1748 goto fail;
David Howellsd84f4f92008-11-14 10:39:23 +11001749
1750 cred = prepare_creds();
1751 if (!cred) {
1752 retval = -ENOMEM;
1753 goto fail;
1754 }
1755
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 down_write(&mm->mmap_sem);
Roland McGrath00ec99d2007-11-11 19:13:43 -08001757 /*
1758 * If another thread got here first, or we are not dumpable, bail out.
1759 */
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001760 if (mm->core_state || !get_dumpable(mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 up_write(&mm->mmap_sem);
David Howellsd84f4f92008-11-14 10:39:23 +11001762 put_cred(cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 goto fail;
1764 }
Alan Coxd6e71142005-06-23 00:09:43 -07001765
1766 /*
1767 * We cannot trust fsuid as being the "true" uid of the
1768 * process nor do we know its entire history. We only know it
1769 * was tainted so we dump it as root in mode 2.
1770 */
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001771 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
Alan Coxd6e71142005-06-23 00:09:43 -07001772 flag = O_EXCL; /* Stop rewrite attacks */
David Howellsd84f4f92008-11-14 10:39:23 +11001773 cred->fsuid = 0; /* Dump root private */
Alan Coxd6e71142005-06-23 00:09:43 -07001774 }
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001775
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001776 retval = coredump_wait(exit_code, &core_state);
David Howellsd84f4f92008-11-14 10:39:23 +11001777 if (retval < 0) {
1778 put_cred(cred);
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001779 goto fail;
David Howellsd84f4f92008-11-14 10:39:23 +11001780 }
1781
1782 old_cred = override_creds(cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783
1784 /*
1785 * Clear any false indication of pending signals that might
1786 * be seen by the filesystem code called to write the core file.
1787 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 clear_thread_flag(TIF_SIGPENDING);
1789
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 /*
1791 * lock_kernel() because format_corename() is controlled by sysctl, which
1792 * uses lock_kernel()
1793 */
1794 lock_kernel();
Oleg Nesterov64093242008-10-18 20:28:22 -07001795 ispipe = format_corename(corename, signr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796 unlock_kernel();
Neil Horman7dc0b222007-10-16 23:26:34 -07001797 /*
1798 * Don't bother to check the RLIMIT_CORE value if core_pattern points
1799 * to a pipe. Since we're not writing directly to the filesystem
1800 * RLIMIT_CORE doesn't really apply, as no actual core file will be
1801 * created unless the pipe reader choses to write out the core file
1802 * at which point file size limits and permissions will be imposed
1803 * as it does with any other process
1804 */
Neil Horman74aadce2007-10-16 23:26:35 -07001805 if ((!ispipe) && (core_limit < binfmt->min_coredump))
Neil Horman7dc0b222007-10-16 23:26:34 -07001806 goto fail_unlock;
1807
Alan Coxc4bbafd2007-04-16 22:53:13 -07001808 if (ispipe) {
Neil Horman74aadce2007-10-16 23:26:35 -07001809 helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
Tetsuo Handa350eaf72009-01-06 14:41:11 -08001810 if (!helper_argv) {
1811 printk(KERN_WARNING "%s failed to allocate memory\n",
1812 __func__);
1813 goto fail_unlock;
1814 }
Neil Horman74aadce2007-10-16 23:26:35 -07001815 /* Terminate the string before the first option */
1816 delimit = strchr(corename, ' ');
1817 if (delimit)
1818 *delimit = '\0';
Neil Horman32321132007-10-16 23:26:36 -07001819 delimit = strrchr(helper_argv[0], '/');
1820 if (delimit)
1821 delimit++;
1822 else
1823 delimit = helper_argv[0];
1824 if (!strcmp(delimit, current->comm)) {
1825 printk(KERN_NOTICE "Recursive core dump detected, "
1826 "aborting\n");
1827 goto fail_unlock;
1828 }
1829
1830 core_limit = RLIM_INFINITY;
1831
Andi Kleend025c9d2006-09-30 23:29:28 -07001832 /* SIGPIPE can happen, but it's just never processed */
Neil Horman32321132007-10-16 23:26:36 -07001833 if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
1834 &file)) {
Andi Kleend025c9d2006-09-30 23:29:28 -07001835 printk(KERN_INFO "Core dump to %s pipe failed\n",
1836 corename);
1837 goto fail_unlock;
1838 }
Andi Kleend025c9d2006-09-30 23:29:28 -07001839 } else
1840 file = filp_open(corename,
Alexey Dobriyan6d4df672006-12-06 20:40:39 -08001841 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1842 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 if (IS_ERR(file))
1844 goto fail_unlock;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001845 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001846 if (inode->i_nlink > 1)
1847 goto close_fail; /* multiple links - don't dump */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001848 if (!ispipe && d_unhashed(file->f_path.dentry))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 goto close_fail;
1850
Andi Kleend025c9d2006-09-30 23:29:28 -07001851 /* AK: actually i see no reason to not allow this for named pipes etc.,
1852 but keep the previous behaviour for now. */
1853 if (!ispipe && !S_ISREG(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 goto close_fail;
Ingo Molnarc46f7392007-11-28 13:59:18 +01001855 /*
1856 * Dont allow local users get cute and trick others to coredump
1857 * into their pre-created files:
1858 */
David Howellsda9592e2008-11-14 10:39:05 +11001859 if (inode->i_uid != current_fsuid())
Ingo Molnarc46f7392007-11-28 13:59:18 +01001860 goto close_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 if (!file->f_op)
1862 goto close_fail;
1863 if (!file->f_op->write)
1864 goto close_fail;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001865 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 goto close_fail;
1867
Neil Horman7dc0b222007-10-16 23:26:34 -07001868 retval = binfmt->core_dump(signr, regs, file, core_limit);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869
1870 if (retval)
1871 current->signal->group_exit_code |= 0x80;
1872close_fail:
1873 filp_close(file, NULL);
1874fail_unlock:
Neil Horman74aadce2007-10-16 23:26:35 -07001875 if (helper_argv)
1876 argv_free(helper_argv);
1877
David Howellsd84f4f92008-11-14 10:39:23 +11001878 revert_creds(old_cred);
1879 put_cred(cred);
Oleg Nesterova94e2d42008-07-25 01:47:46 -07001880 coredump_finish(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881fail:
WANG Cong8cd3ac32009-01-06 14:42:48 -08001882 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883}