blob: cecee501ce78805c32c9d007c658fce1e87b0a97 [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <linux/highmem.h>
37#include <linux/spinlock.h>
38#include <linux/key.h>
39#include <linux/personality.h>
40#include <linux/binfmts.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <linux/utsname.h>
Sukadev Bhattiprolu84d73782006-12-08 02:38:01 -080042#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <linux/module.h>
44#include <linux/namei.h>
45#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/mount.h>
47#include <linux/security.h>
48#include <linux/syscalls.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070049#include <linux/tsacct_kern.h>
Matt Helsley9f460802005-11-07 00:59:16 -080050#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040051#include <linux/audit.h>
Roland McGrath6341c392008-07-25 19:45:44 -070052#include <linux/tracehook.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54#include <asm/uaccess.h>
55#include <asm/mmu_context.h>
Ollie Wildb6a2fea2007-07-19 01:48:16 -070056#include <asm/tlb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
58#ifdef CONFIG_KMOD
59#include <linux/kmod.h>
60#endif
61
David Woodhouse702773b2008-06-16 12:11:54 +010062#ifdef __alpha__
63/* for /sbin/loader handling in search_binary_handler() */
64#include <linux/a.out.h>
65#endif
66
Linus Torvalds1da177e2005-04-16 15:20:36 -070067int core_uses_pid;
Dan Aloni71ce92f2007-05-16 22:11:16 -070068char core_pattern[CORENAME_MAX_SIZE] = "core";
Alan Coxd6e71142005-06-23 00:09:43 -070069int suid_dumpable = 0;
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071/* The maximal length of core_pattern is also specified in sysctl.c */
72
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070073static LIST_HEAD(formats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070074static DEFINE_RWLOCK(binfmt_lock);
75
76int register_binfmt(struct linux_binfmt * fmt)
77{
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 if (!fmt)
79 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 write_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070081 list_add(&fmt->lh, &formats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 write_unlock(&binfmt_lock);
83 return 0;
84}
85
86EXPORT_SYMBOL(register_binfmt);
87
Alexey Dobriyanf6b450d2007-10-16 23:26:04 -070088void unregister_binfmt(struct linux_binfmt * fmt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070089{
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 write_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070091 list_del(&fmt->lh);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 write_unlock(&binfmt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
95EXPORT_SYMBOL(unregister_binfmt);
96
97static inline void put_binfmt(struct linux_binfmt * fmt)
98{
99 module_put(fmt->module);
100}
101
102/*
103 * Note that a shared library must be both readable and executable due to
104 * security reasons.
105 *
106 * Also note that we take the address to load from from the file itself.
107 */
108asmlinkage long sys_uselib(const char __user * library)
109{
Al Viro964bd182008-07-26 03:33:14 -0400110 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 struct nameidata nd;
Al Viro964bd182008-07-26 03:33:14 -0400112 char *tmp = getname(library);
113 int error = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
Al Viro964bd182008-07-26 03:33:14 -0400115 if (!IS_ERR(tmp)) {
116 error = path_lookup_open(AT_FDCWD, tmp,
117 LOOKUP_FOLLOW, &nd,
118 FMODE_READ|FMODE_EXEC);
119 putname(tmp);
120 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 if (error)
122 goto out;
123
124 error = -EINVAL;
Jan Blunck4ac91372008-02-14 19:34:32 -0800125 if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 goto exit;
127
Al Viro30524472008-07-22 00:02:33 -0400128 error = -EACCES;
129 if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
130 goto exit;
131
Al Virob77b0642008-07-17 09:37:02 -0400132 error = vfs_permission(&nd, MAY_READ | MAY_EXEC | MAY_OPEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 if (error)
134 goto exit;
135
Andi Kleenabe8be32008-02-08 04:20:23 -0800136 file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 error = PTR_ERR(file);
138 if (IS_ERR(file))
139 goto out;
140
141 error = -ENOEXEC;
142 if(file->f_op) {
143 struct linux_binfmt * fmt;
144
145 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -0700146 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 if (!fmt->load_shlib)
148 continue;
149 if (!try_module_get(fmt->module))
150 continue;
151 read_unlock(&binfmt_lock);
152 error = fmt->load_shlib(file);
153 read_lock(&binfmt_lock);
154 put_binfmt(fmt);
155 if (error != -ENOEXEC)
156 break;
157 }
158 read_unlock(&binfmt_lock);
159 }
160 fput(file);
161out:
162 return error;
163exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700164 release_open_intent(&nd);
Jan Blunck1d957f92008-02-14 19:34:35 -0800165 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 goto out;
167}
168
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700169#ifdef CONFIG_MMU
170
171static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
172 int write)
173{
174 struct page *page;
175 int ret;
176
177#ifdef CONFIG_STACK_GROWSUP
178 if (write) {
179 ret = expand_stack_downwards(bprm->vma, pos);
180 if (ret < 0)
181 return NULL;
182 }
183#endif
184 ret = get_user_pages(current, bprm->mm, pos,
185 1, write, 1, &page, NULL);
186 if (ret <= 0)
187 return NULL;
188
189 if (write) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700190 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800191 struct rlimit *rlim;
192
193 /*
194 * We've historically supported up to 32 pages (ARG_MAX)
195 * of argument strings even with small stacks
196 */
197 if (size <= ARG_MAX)
198 return page;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700199
200 /*
201 * Limit to 1/4-th the stack size for the argv+env strings.
202 * This ensures that:
203 * - the remaining binfmt code will not run out of stack space,
204 * - the program will have a reasonable amount of stack left
205 * to work from.
206 */
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800207 rlim = current->signal->rlim;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700208 if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
209 put_page(page);
210 return NULL;
211 }
212 }
213
214 return page;
215}
216
217static void put_arg_page(struct page *page)
218{
219 put_page(page);
220}
221
222static void free_arg_page(struct linux_binprm *bprm, int i)
223{
224}
225
226static void free_arg_pages(struct linux_binprm *bprm)
227{
228}
229
230static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
231 struct page *page)
232{
233 flush_cache_page(bprm->vma, pos, page_to_pfn(page));
234}
235
236static int __bprm_mm_init(struct linux_binprm *bprm)
237{
238 int err = -ENOMEM;
239 struct vm_area_struct *vma = NULL;
240 struct mm_struct *mm = bprm->mm;
241
242 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
243 if (!vma)
244 goto err;
245
246 down_write(&mm->mmap_sem);
247 vma->vm_mm = mm;
248
249 /*
250 * Place the stack at the largest stack address the architecture
251 * supports. Later, we'll move this to an appropriate place. We don't
252 * use STACK_TOP because that can depend on attributes which aren't
253 * configured yet.
254 */
255 vma->vm_end = STACK_TOP_MAX;
256 vma->vm_start = vma->vm_end - PAGE_SIZE;
257
258 vma->vm_flags = VM_STACK_FLAGS;
Coly Li3ed75eb2007-10-18 23:39:15 -0700259 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700260 err = insert_vm_struct(mm, vma);
261 if (err) {
262 up_write(&mm->mmap_sem);
263 goto err;
264 }
265
266 mm->stack_vm = mm->total_vm = 1;
267 up_write(&mm->mmap_sem);
268
269 bprm->p = vma->vm_end - sizeof(void *);
270
271 return 0;
272
273err:
274 if (vma) {
275 bprm->vma = NULL;
276 kmem_cache_free(vm_area_cachep, vma);
277 }
278
279 return err;
280}
281
282static bool valid_arg_len(struct linux_binprm *bprm, long len)
283{
284 return len <= MAX_ARG_STRLEN;
285}
286
287#else
288
289static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
290 int write)
291{
292 struct page *page;
293
294 page = bprm->page[pos / PAGE_SIZE];
295 if (!page && write) {
296 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
297 if (!page)
298 return NULL;
299 bprm->page[pos / PAGE_SIZE] = page;
300 }
301
302 return page;
303}
304
305static void put_arg_page(struct page *page)
306{
307}
308
309static void free_arg_page(struct linux_binprm *bprm, int i)
310{
311 if (bprm->page[i]) {
312 __free_page(bprm->page[i]);
313 bprm->page[i] = NULL;
314 }
315}
316
317static void free_arg_pages(struct linux_binprm *bprm)
318{
319 int i;
320
321 for (i = 0; i < MAX_ARG_PAGES; i++)
322 free_arg_page(bprm, i);
323}
324
325static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
326 struct page *page)
327{
328}
329
330static int __bprm_mm_init(struct linux_binprm *bprm)
331{
332 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
333 return 0;
334}
335
336static bool valid_arg_len(struct linux_binprm *bprm, long len)
337{
338 return len <= bprm->p;
339}
340
341#endif /* CONFIG_MMU */
342
343/*
344 * Create a new mm_struct and populate it with a temporary stack
345 * vm_area_struct. We don't have enough context at this point to set the stack
346 * flags, permissions, and offset, so we use temporary values. We'll update
347 * them later in setup_arg_pages().
348 */
349int bprm_mm_init(struct linux_binprm *bprm)
350{
351 int err;
352 struct mm_struct *mm = NULL;
353
354 bprm->mm = mm = mm_alloc();
355 err = -ENOMEM;
356 if (!mm)
357 goto err;
358
359 err = init_new_context(current, mm);
360 if (err)
361 goto err;
362
363 err = __bprm_mm_init(bprm);
364 if (err)
365 goto err;
366
367 return 0;
368
369err:
370 if (mm) {
371 bprm->mm = NULL;
372 mmdrop(mm);
373 }
374
375 return err;
376}
377
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378/*
379 * count() counts the number of strings in array ARGV.
380 */
381static int count(char __user * __user * argv, int max)
382{
383 int i = 0;
384
385 if (argv != NULL) {
386 for (;;) {
387 char __user * p;
388
389 if (get_user(p, argv))
390 return -EFAULT;
391 if (!p)
392 break;
393 argv++;
394 if(++i > max)
395 return -E2BIG;
396 cond_resched();
397 }
398 }
399 return i;
400}
401
402/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700403 * 'copy_strings()' copies argument/environment strings from the old
404 * processes's memory to the new process's stack. The call to get_user_pages()
405 * ensures the destination page is created and not swapped out.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700407static int copy_strings(int argc, char __user * __user * argv,
408 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409{
410 struct page *kmapped_page = NULL;
411 char *kaddr = NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700412 unsigned long kpos = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 int ret;
414
415 while (argc-- > 0) {
416 char __user *str;
417 int len;
418 unsigned long pos;
419
420 if (get_user(str, argv+argc) ||
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700421 !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 ret = -EFAULT;
423 goto out;
424 }
425
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700426 if (!valid_arg_len(bprm, len)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 ret = -E2BIG;
428 goto out;
429 }
430
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700431 /* We're going to work our way backwords. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 pos = bprm->p;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700433 str += len;
434 bprm->p -= len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
436 while (len > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 int offset, bytes_to_copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438
439 offset = pos % PAGE_SIZE;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700440 if (offset == 0)
441 offset = PAGE_SIZE;
442
443 bytes_to_copy = offset;
444 if (bytes_to_copy > len)
445 bytes_to_copy = len;
446
447 offset -= bytes_to_copy;
448 pos -= bytes_to_copy;
449 str -= bytes_to_copy;
450 len -= bytes_to_copy;
451
452 if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
453 struct page *page;
454
455 page = get_arg_page(bprm, pos, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 if (!page) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700457 ret = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 goto out;
459 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700461 if (kmapped_page) {
462 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700464 put_arg_page(kmapped_page);
465 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 kmapped_page = page;
467 kaddr = kmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700468 kpos = pos & PAGE_MASK;
469 flush_arg_page(bprm, kpos, kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700471 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 ret = -EFAULT;
473 goto out;
474 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 }
476 }
477 ret = 0;
478out:
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700479 if (kmapped_page) {
480 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700482 put_arg_page(kmapped_page);
483 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 return ret;
485}
486
487/*
488 * Like copy_strings, but get argv and its values from kernel memory.
489 */
490int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
491{
492 int r;
493 mm_segment_t oldfs = get_fs();
494 set_fs(KERNEL_DS);
495 r = copy_strings(argc, (char __user * __user *)argv, bprm);
496 set_fs(oldfs);
497 return r;
498}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499EXPORT_SYMBOL(copy_strings_kernel);
500
501#ifdef CONFIG_MMU
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700504 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
505 * the binfmt code determines where the new stack should reside, we shift it to
506 * its final location. The process proceeds as follows:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 *
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700508 * 1) Use shift to calculate the new vma endpoints.
509 * 2) Extend vma to cover both the old and new ranges. This ensures the
510 * arguments passed to subsequent functions are consistent.
511 * 3) Move vma's page tables to the new range.
512 * 4) Free up any cleared pgd range.
513 * 5) Shrink the vma to cover only the new range.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700515static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516{
517 struct mm_struct *mm = vma->vm_mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700518 unsigned long old_start = vma->vm_start;
519 unsigned long old_end = vma->vm_end;
520 unsigned long length = old_end - old_start;
521 unsigned long new_start = old_start - shift;
522 unsigned long new_end = old_end - shift;
523 struct mmu_gather *tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700525 BUG_ON(new_start > new_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700527 /*
528 * ensure there are no vmas between where we want to go
529 * and where we are
530 */
531 if (vma != find_vma(mm, new_start))
532 return -EFAULT;
533
534 /*
535 * cover the whole range: [new_start, old_end)
536 */
537 vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
538
539 /*
540 * move the page tables downwards, on failure we rely on
541 * process cleanup to remove whatever mess we made.
542 */
543 if (length != move_page_tables(vma, old_start,
544 vma, new_start, length))
545 return -ENOMEM;
546
547 lru_add_drain();
548 tlb = tlb_gather_mmu(mm, 0);
549 if (new_end > old_start) {
550 /*
551 * when the old and new regions overlap clear from new_end.
552 */
Jan Beulich42b77722008-07-23 21:27:10 -0700553 free_pgd_range(tlb, new_end, old_end, new_end,
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700554 vma->vm_next ? vma->vm_next->vm_start : 0);
555 } else {
556 /*
557 * otherwise, clean from old_start; this is done to not touch
558 * the address space in [new_end, old_start) some architectures
559 * have constraints on va-space that make this illegal (IA64) -
560 * for the others its just a little faster.
561 */
Jan Beulich42b77722008-07-23 21:27:10 -0700562 free_pgd_range(tlb, old_start, old_end, new_end,
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700563 vma->vm_next ? vma->vm_next->vm_start : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700565 tlb_finish_mmu(tlb, new_end, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700567 /*
568 * shrink the vma to just the new range.
569 */
570 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
571
572 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573}
574
575#define EXTRA_STACK_VM_PAGES 20 /* random */
576
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700577/*
578 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
579 * the stack is optionally relocated, and some extra space is added.
580 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581int setup_arg_pages(struct linux_binprm *bprm,
582 unsigned long stack_top,
583 int executable_stack)
584{
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700585 unsigned long ret;
586 unsigned long stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 struct mm_struct *mm = current->mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700588 struct vm_area_struct *vma = bprm->vma;
589 struct vm_area_struct *prev = NULL;
590 unsigned long vm_flags;
591 unsigned long stack_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592
593#ifdef CONFIG_STACK_GROWSUP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 /* Limit stack size to 1GB */
595 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
596 if (stack_base > (1 << 30))
597 stack_base = 1 << 30;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700599 /* Make sure we didn't let the argument array grow too large. */
600 if (vma->vm_end - vma->vm_start > stack_base)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 return -ENOMEM;
602
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700603 stack_base = PAGE_ALIGN(stack_top - stack_base);
604
605 stack_shift = vma->vm_start - stack_base;
606 mm->arg_start = bprm->p - stack_shift;
607 bprm->p = vma->vm_end - stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608#else
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700609 stack_top = arch_align_stack(stack_top);
610 stack_top = PAGE_ALIGN(stack_top);
611 stack_shift = vma->vm_end - stack_top;
612
613 bprm->p -= stack_shift;
614 mm->arg_start = bprm->p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615#endif
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700616
617 if (bprm->loader)
618 bprm->loader -= stack_shift;
619 bprm->exec -= stack_shift;
620
621 down_write(&mm->mmap_sem);
Hugh Dickins96a8e132008-07-10 21:19:20 +0100622 vm_flags = VM_STACK_FLAGS;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700623
624 /*
625 * Adjust stack execute permissions; explicitly enable for
626 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
627 * (arch default) otherwise.
628 */
629 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
630 vm_flags |= VM_EXEC;
631 else if (executable_stack == EXSTACK_DISABLE_X)
632 vm_flags &= ~VM_EXEC;
633 vm_flags |= mm->def_flags;
634
635 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
636 vm_flags);
637 if (ret)
638 goto out_unlock;
639 BUG_ON(prev != vma);
640
641 /* Move stack pages down in memory. */
642 if (stack_shift) {
643 ret = shift_arg_pages(vma, stack_shift);
644 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 return ret;
647 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 }
649
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700650#ifdef CONFIG_STACK_GROWSUP
651 stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
652#else
653 stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
654#endif
655 ret = expand_stack(vma, stack_base);
656 if (ret)
657 ret = -EFAULT;
658
659out_unlock:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 return 0;
662}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663EXPORT_SYMBOL(setup_arg_pages);
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665#endif /* CONFIG_MMU */
666
667struct file *open_exec(const char *name)
668{
669 struct nameidata nd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 struct file *file;
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200671 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200673 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
674 FMODE_READ|FMODE_EXEC);
675 if (err)
676 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200678 err = -EACCES;
679 if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
680 goto out_path_put;
681
Al Viro30524472008-07-22 00:02:33 -0400682 if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
683 goto out_path_put;
684
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200685 err = vfs_permission(&nd, MAY_EXEC | MAY_OPEN);
686 if (err)
687 goto out_path_put;
688
689 file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
690 if (IS_ERR(file))
691 return file;
692
693 err = deny_write_access(file);
694 if (err) {
695 fput(file);
696 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
Christoph Hellwige56b6a52008-05-19 07:53:34 +0200699 return file;
700
701 out_path_put:
702 release_open_intent(&nd);
703 path_put(&nd.path);
704 out:
705 return ERR_PTR(err);
706}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707EXPORT_SYMBOL(open_exec);
708
709int kernel_read(struct file *file, unsigned long offset,
710 char *addr, unsigned long count)
711{
712 mm_segment_t old_fs;
713 loff_t pos = offset;
714 int result;
715
716 old_fs = get_fs();
717 set_fs(get_ds());
718 /* The cast to a user pointer is valid due to the set_fs() */
719 result = vfs_read(file, (void __user *)addr, count, &pos);
720 set_fs(old_fs);
721 return result;
722}
723
724EXPORT_SYMBOL(kernel_read);
725
726static int exec_mmap(struct mm_struct *mm)
727{
728 struct task_struct *tsk;
729 struct mm_struct * old_mm, *active_mm;
730
731 /* Notify parent that we're no longer interested in the old VM */
732 tsk = current;
733 old_mm = current->mm;
734 mm_release(tsk, old_mm);
735
736 if (old_mm) {
737 /*
738 * Make sure that if there is a core dump in progress
739 * for the old mm, we get out and die instead of going
740 * through with the exec. We must hold mmap_sem around
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700741 * checking core_state and changing tsk->mm.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 */
743 down_read(&old_mm->mmap_sem);
Oleg Nesterov999d9fc2008-07-25 01:47:41 -0700744 if (unlikely(old_mm->core_state)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 up_read(&old_mm->mmap_sem);
746 return -EINTR;
747 }
748 }
749 task_lock(tsk);
750 active_mm = tsk->active_mm;
751 tsk->mm = mm;
752 tsk->active_mm = mm;
753 activate_mm(active_mm, mm);
754 task_unlock(tsk);
755 arch_pick_mmap_layout(mm);
756 if (old_mm) {
757 up_read(&old_mm->mmap_sem);
Eric Sesterhenn7dddb122006-04-01 01:13:38 +0200758 BUG_ON(active_mm != old_mm);
Balbir Singh31a78f22008-09-28 23:09:31 +0100759 mm_update_next_owner(old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 mmput(old_mm);
761 return 0;
762 }
763 mmdrop(active_mm);
764 return 0;
765}
766
767/*
768 * This function makes sure the current process has its own signal table,
769 * so that flush_signal_handlers can later reset the handlers without
770 * disturbing other processes. (Other processes might share the signal
771 * table via the CLONE_SIGHAND option to clone().)
772 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800773static int de_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774{
775 struct signal_struct *sig = tsk->signal;
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700776 struct sighand_struct *oldsighand = tsk->sighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 spinlock_t *lock = &oldsighand->siglock;
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300778 struct task_struct *leader = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 int count;
780
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700781 if (thread_group_empty(tsk))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 goto no_thread_group;
783
784 /*
785 * Kill all other threads in the thread group.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 spin_lock_irq(lock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800788 if (signal_group_exit(sig)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 /*
790 * Another group action in progress, just
791 * return so that the signal is processed.
792 */
793 spin_unlock_irq(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 return -EAGAIN;
795 }
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800796 sig->group_exit_task = tsk;
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700797 zap_other_threads(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
Oleg Nesterovfea9d172008-02-08 04:19:19 -0800799 /* Account for the thread group leader hanging around: */
800 count = thread_group_leader(tsk) ? 1 : 2;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700801 sig->notify_count = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 while (atomic_read(&sig->count) > count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 __set_current_state(TASK_UNINTERRUPTIBLE);
804 spin_unlock_irq(lock);
805 schedule();
806 spin_lock_irq(lock);
807 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 spin_unlock_irq(lock);
809
810 /*
811 * At this point all other threads have exited, all we have to
812 * do is to wait for the thread group leader to become inactive,
813 * and to assume its PID:
814 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700815 if (!thread_group_leader(tsk)) {
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700816 leader = tsk->group_leader;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700817
Oleg Nesterov2800d8d2008-04-30 00:53:12 -0700818 sig->notify_count = -1; /* for exit_notify() */
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700819 for (;;) {
820 write_lock_irq(&tasklist_lock);
821 if (likely(leader->exit_state))
822 break;
823 __set_current_state(TASK_UNINTERRUPTIBLE);
824 write_unlock_irq(&tasklist_lock);
825 schedule();
826 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827
Oleg Nesterov7a5e8732008-04-30 00:53:04 -0700828 if (unlikely(task_child_reaper(tsk) == leader))
829 task_active_pid_ns(tsk)->child_reaper = tsk;
Roland McGrathf5e90282006-04-10 22:54:16 -0700830 /*
831 * The only record we have of the real-time age of a
832 * process, regardless of execs it's done, is start_time.
833 * All the past CPU time is accumulated in signal_struct
834 * from sister threads now dead. But in this non-leader
835 * exec, nothing survives from the original leader thread,
836 * whose birth marks the true age of this process now.
837 * When we take on its identity by switching to its PID, we
838 * also take its birthdate (always earlier than our own).
839 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700840 tsk->start_time = leader->start_time;
Roland McGrathf5e90282006-04-10 22:54:16 -0700841
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700842 BUG_ON(!same_thread_group(leader, tsk));
843 BUG_ON(has_group_leader_pid(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 /*
845 * An exec() starts a new thread group with the
846 * TGID of the previous thread group. Rehash the
847 * two threads with a switched PID, and release
848 * the former thread group leader:
849 */
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800850
851 /* Become a process group leader with the old leader's pid.
Eric W. Biedermanc18258c2006-09-27 01:51:06 -0700852 * The old leader becomes a thread of the this thread group.
853 * Note: The old leader also uses this pid until release_task
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800854 * is called. Odd but simple and correct.
855 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700856 detach_pid(tsk, PIDTYPE_PID);
857 tsk->pid = leader->pid;
Sukadev Bhattiprolu3743ca02007-10-18 23:39:51 -0700858 attach_pid(tsk, PIDTYPE_PID, task_pid(leader));
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700859 transfer_pid(leader, tsk, PIDTYPE_PGID);
860 transfer_pid(leader, tsk, PIDTYPE_SID);
861 list_replace_rcu(&leader->tasks, &tsk->tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700863 tsk->group_leader = tsk;
864 leader->group_leader = tsk;
Eric W. Biedermande12a782006-04-10 17:16:49 -0600865
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700866 tsk->exit_signal = SIGCHLD;
Oleg Nesterov962b5642005-11-23 13:37:43 -0800867
868 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
869 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
871 write_unlock_irq(&tasklist_lock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800872 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700874 sig->group_exit_task = NULL;
875 sig->notify_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876
877no_thread_group:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 exit_itimers(sig);
Oleg Nesterovcbaffba2008-05-26 20:55:42 +0400879 flush_itimer_signals();
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300880 if (leader)
881 release_task(leader);
882
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700883 if (atomic_read(&oldsighand->count) != 1) {
884 struct sighand_struct *newsighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 /*
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700886 * This ->sighand is shared with the CLONE_SIGHAND
887 * but not CLONE_THREAD task, switch to the new one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 */
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700889 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
890 if (!newsighand)
891 return -ENOMEM;
892
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 atomic_set(&newsighand->count, 1);
894 memcpy(newsighand->action, oldsighand->action,
895 sizeof(newsighand->action));
896
897 write_lock_irq(&tasklist_lock);
898 spin_lock(&oldsighand->siglock);
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700899 rcu_assign_pointer(tsk->sighand, newsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 spin_unlock(&oldsighand->siglock);
901 write_unlock_irq(&tasklist_lock);
902
Davide Libenzifba2afa2007-05-10 22:23:13 -0700903 __cleanup_sighand(oldsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 }
905
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700906 BUG_ON(!thread_group_leader(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 return 0;
908}
Oleg Nesterov0840a902007-10-16 23:27:22 -0700909
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910/*
911 * These functions flushes out all traces of the currently running executable
912 * so that a new one can be started
913 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800914static void flush_old_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915{
916 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700917 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918
919 spin_lock(&files->file_lock);
920 for (;;) {
921 unsigned long set, i;
922
923 j++;
924 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700925 fdt = files_fdtable(files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800926 if (i >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700928 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 if (!set)
930 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700931 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 spin_unlock(&files->file_lock);
933 for ( ; set ; i++,set >>= 1) {
934 if (set & 1) {
935 sys_close(i);
936 }
937 }
938 spin_lock(&files->file_lock);
939
940 }
941 spin_unlock(&files->file_lock);
942}
943
Andrew Morton59714d62008-02-04 22:27:21 -0800944char *get_task_comm(char *buf, struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945{
946 /* buf must be at least sizeof(tsk->comm) in size */
947 task_lock(tsk);
948 strncpy(buf, tsk->comm, sizeof(tsk->comm));
949 task_unlock(tsk);
Andrew Morton59714d62008-02-04 22:27:21 -0800950 return buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951}
952
953void set_task_comm(struct task_struct *tsk, char *buf)
954{
955 task_lock(tsk);
956 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
957 task_unlock(tsk);
958}
959
960int flush_old_exec(struct linux_binprm * bprm)
961{
962 char * name;
963 int i, ch, retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 char tcomm[sizeof(current->comm)];
965
966 /*
967 * Make sure we have a private signal table and that
968 * we are unassociated from the previous thread group.
969 */
970 retval = de_thread(current);
971 if (retval)
972 goto out;
973
Matt Helsley925d1c42008-04-29 01:01:36 -0700974 set_mm_exe_file(bprm->mm, bprm->file);
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 * Release all of the old mmap stuff
978 */
979 retval = exec_mmap(bprm->mm);
980 if (retval)
Al Virofd8328b2008-04-22 05:11:59 -0400981 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
983 bprm->mm = NULL; /* We're using it now */
984
985 /* This is the point of no return */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 current->sas_ss_sp = current->sas_ss_size = 0;
987
988 if (current->euid == current->uid && current->egid == current->gid)
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700989 set_dumpable(current->mm, 1);
Alan Coxd6e71142005-06-23 00:09:43 -0700990 else
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700991 set_dumpable(current->mm, suid_dumpable);
Alan Coxd6e71142005-06-23 00:09:43 -0700992
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700994
995 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 for (i=0; (ch = *(name++)) != '\0';) {
997 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700998 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 else
1000 if (i < (sizeof(tcomm) - 1))
1001 tcomm[i++] = ch;
1002 }
1003 tcomm[i] = '\0';
1004 set_task_comm(current, tcomm);
1005
1006 current->flags &= ~PF_RANDOMIZE;
1007 flush_thread();
1008
Benjamin Herrenschmidt0551fbd2006-02-28 16:59:19 -08001009 /* Set the new mm task size. We have to do that late because it may
1010 * depend on TIF_32BIT which is only updated in flush_thread() on
1011 * some architectures like powerpc
1012 */
1013 current->mm->task_size = TASK_SIZE;
1014
Marcel Holtmannd2d56c52007-08-17 21:47:58 +02001015 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
1016 suid_keys(current);
1017 set_dumpable(current->mm, suid_dumpable);
1018 current->pdeath_signal = 0;
1019 } else if (file_permission(bprm->file, MAY_READ) ||
1020 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 suid_keys(current);
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001022 set_dumpable(current->mm, suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 }
1024
1025 /* An exec changes our domain. We are no longer part of the thread
1026 group */
1027
1028 current->self_exec_id++;
1029
1030 flush_signal_handlers(current, 0);
1031 flush_old_files(current->files);
1032
1033 return 0;
1034
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035out:
1036 return retval;
1037}
1038
1039EXPORT_SYMBOL(flush_old_exec);
1040
1041/*
1042 * Fill the binprm structure from the inode.
1043 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
1044 */
1045int prepare_binprm(struct linux_binprm *bprm)
1046{
1047 int mode;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001048 struct inode * inode = bprm->file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 int retval;
1050
1051 mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 if (bprm->file->f_op == NULL)
1053 return -EACCES;
1054
1055 bprm->e_uid = current->euid;
1056 bprm->e_gid = current->egid;
1057
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001058 if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059 /* Set-uid? */
1060 if (mode & S_ISUID) {
1061 current->personality &= ~PER_CLEAR_ON_SETID;
1062 bprm->e_uid = inode->i_uid;
1063 }
1064
1065 /* Set-gid? */
1066 /*
1067 * If setgid is set but no group execute bit then this
1068 * is a candidate for mandatory locking, not a setgid
1069 * executable.
1070 */
1071 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1072 current->personality &= ~PER_CLEAR_ON_SETID;
1073 bprm->e_gid = inode->i_gid;
1074 }
1075 }
1076
1077 /* fill in binprm security blob */
1078 retval = security_bprm_set(bprm);
1079 if (retval)
1080 return retval;
1081
1082 memset(bprm->buf,0,BINPRM_BUF_SIZE);
1083 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
1084}
1085
1086EXPORT_SYMBOL(prepare_binprm);
1087
Arjan van de Ven858119e2006-01-14 13:20:43 -08001088static int unsafe_exec(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089{
Roland McGrath6341c392008-07-25 19:45:44 -07001090 int unsafe = tracehook_unsafe_exec(p);
1091
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 if (atomic_read(&p->fs->count) > 1 ||
1093 atomic_read(&p->files->count) > 1 ||
1094 atomic_read(&p->sighand->count) > 1)
1095 unsafe |= LSM_UNSAFE_SHARE;
1096
1097 return unsafe;
1098}
1099
1100void compute_creds(struct linux_binprm *bprm)
1101{
1102 int unsafe;
1103
Marcel Holtmannd2d56c52007-08-17 21:47:58 +02001104 if (bprm->e_uid != current->uid) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 suid_keys(current);
Marcel Holtmannd2d56c52007-08-17 21:47:58 +02001106 current->pdeath_signal = 0;
1107 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 exec_keys(current);
1109
1110 task_lock(current);
1111 unsafe = unsafe_exec(current);
1112 security_bprm_apply_creds(bprm, unsafe);
1113 task_unlock(current);
1114 security_bprm_post_apply_creds(bprm);
1115}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116EXPORT_SYMBOL(compute_creds);
1117
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001118/*
1119 * Arguments are '\0' separated strings found at the location bprm->p
1120 * points to; chop off the first by relocating brpm->p to right after
1121 * the first '\0' encountered.
1122 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001123int remove_arg_zero(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124{
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001125 int ret = 0;
1126 unsigned long offset;
1127 char *kaddr;
1128 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001130 if (!bprm->argc)
1131 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001133 do {
1134 offset = bprm->p & ~PAGE_MASK;
1135 page = get_arg_page(bprm, bprm->p, 0);
1136 if (!page) {
1137 ret = -EFAULT;
1138 goto out;
1139 }
1140 kaddr = kmap_atomic(page, KM_USER0);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001141
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001142 for (; offset < PAGE_SIZE && kaddr[offset];
1143 offset++, bprm->p++)
1144 ;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001145
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001146 kunmap_atomic(kaddr, KM_USER0);
1147 put_arg_page(page);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001148
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001149 if (offset == PAGE_SIZE)
1150 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
1151 } while (offset == PAGE_SIZE);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001152
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001153 bprm->p++;
1154 bprm->argc--;
1155 ret = 0;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001156
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001157out:
1158 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160EXPORT_SYMBOL(remove_arg_zero);
1161
1162/*
1163 * cycle the list of binary formats handler, until one recognizes the image
1164 */
1165int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1166{
1167 int try,retval;
1168 struct linux_binfmt *fmt;
David Woodhouse702773b2008-06-16 12:11:54 +01001169#ifdef __alpha__
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 /* handle /sbin/loader.. */
1171 {
1172 struct exec * eh = (struct exec *) bprm->buf;
1173
1174 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1175 (eh->fh.f_flags & 0x3000) == 0x3000)
1176 {
1177 struct file * file;
1178 unsigned long loader;
1179
1180 allow_write_access(bprm->file);
1181 fput(bprm->file);
1182 bprm->file = NULL;
1183
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001184 loader = bprm->vma->vm_end - sizeof(void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185
1186 file = open_exec("/sbin/loader");
1187 retval = PTR_ERR(file);
1188 if (IS_ERR(file))
1189 return retval;
1190
1191 /* Remember if the application is TASO. */
1192 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1193
1194 bprm->file = file;
1195 bprm->loader = loader;
1196 retval = prepare_binprm(bprm);
1197 if (retval<0)
1198 return retval;
1199 /* should call search_binary_handler recursively here,
1200 but it does not matter */
1201 }
1202 }
1203#endif
1204 retval = security_bprm_check(bprm);
1205 if (retval)
1206 return retval;
1207
1208 /* kernel module loader fixup */
1209 /* so we don't try to load run modprobe in kernel space. */
1210 set_fs(USER_DS);
Al Viro473ae302006-04-26 14:04:08 -04001211
1212 retval = audit_bprm(bprm);
1213 if (retval)
1214 return retval;
1215
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 retval = -ENOENT;
1217 for (try=0; try<2; try++) {
1218 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -07001219 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1221 if (!fn)
1222 continue;
1223 if (!try_module_get(fmt->module))
1224 continue;
1225 read_unlock(&binfmt_lock);
1226 retval = fn(bprm, regs);
1227 if (retval >= 0) {
Roland McGrath6341c392008-07-25 19:45:44 -07001228 tracehook_report_exec(fmt, bprm, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 put_binfmt(fmt);
1230 allow_write_access(bprm->file);
1231 if (bprm->file)
1232 fput(bprm->file);
1233 bprm->file = NULL;
1234 current->did_exec = 1;
Matt Helsley9f460802005-11-07 00:59:16 -08001235 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 return retval;
1237 }
1238 read_lock(&binfmt_lock);
1239 put_binfmt(fmt);
1240 if (retval != -ENOEXEC || bprm->mm == NULL)
1241 break;
1242 if (!bprm->file) {
1243 read_unlock(&binfmt_lock);
1244 return retval;
1245 }
1246 }
1247 read_unlock(&binfmt_lock);
1248 if (retval != -ENOEXEC || bprm->mm == NULL) {
1249 break;
1250#ifdef CONFIG_KMOD
1251 }else{
1252#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1253 if (printable(bprm->buf[0]) &&
1254 printable(bprm->buf[1]) &&
1255 printable(bprm->buf[2]) &&
1256 printable(bprm->buf[3]))
1257 break; /* -ENOEXEC */
1258 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1259#endif
1260 }
1261 }
1262 return retval;
1263}
1264
1265EXPORT_SYMBOL(search_binary_handler);
1266
Al Viro08a6fac2008-05-10 16:38:25 -04001267void free_bprm(struct linux_binprm *bprm)
1268{
1269 free_arg_pages(bprm);
1270 kfree(bprm);
1271}
1272
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273/*
1274 * sys_execve() executes a new program.
1275 */
1276int do_execve(char * filename,
1277 char __user *__user *argv,
1278 char __user *__user *envp,
1279 struct pt_regs * regs)
1280{
1281 struct linux_binprm *bprm;
1282 struct file *file;
Al Viro3b125382008-04-22 05:31:30 -04001283 struct files_struct *displaced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285
Al Viro3b125382008-04-22 05:31:30 -04001286 retval = unshare_files(&displaced);
Al Virofd8328b2008-04-22 05:11:59 -04001287 if (retval)
1288 goto out_ret;
1289
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 retval = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001291 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 if (!bprm)
Al Virofd8328b2008-04-22 05:11:59 -04001293 goto out_files;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294
1295 file = open_exec(filename);
1296 retval = PTR_ERR(file);
1297 if (IS_ERR(file))
1298 goto out_kfree;
1299
1300 sched_exec();
1301
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 bprm->file = file;
1303 bprm->filename = filename;
1304 bprm->interp = filename;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001305
1306 retval = bprm_mm_init(bprm);
1307 if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 goto out_file;
1309
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001310 bprm->argc = count(argv, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 if ((retval = bprm->argc) < 0)
1312 goto out_mm;
1313
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001314 bprm->envc = count(envp, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 if ((retval = bprm->envc) < 0)
1316 goto out_mm;
1317
1318 retval = security_bprm_alloc(bprm);
1319 if (retval)
1320 goto out;
1321
1322 retval = prepare_binprm(bprm);
1323 if (retval < 0)
1324 goto out;
1325
1326 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1327 if (retval < 0)
1328 goto out;
1329
1330 bprm->exec = bprm->p;
1331 retval = copy_strings(bprm->envc, envp, bprm);
1332 if (retval < 0)
1333 goto out;
1334
1335 retval = copy_strings(bprm->argc, argv, bprm);
1336 if (retval < 0)
1337 goto out;
1338
Oleg Nesterov7b34e422008-07-25 01:47:37 -07001339 current->flags &= ~PF_KTHREAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 retval = search_binary_handler(bprm,regs);
1341 if (retval >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 /* execve success */
1343 security_bprm_free(bprm);
1344 acct_update_integrals(current);
Al Viro08a6fac2008-05-10 16:38:25 -04001345 free_bprm(bprm);
Al Viro3b125382008-04-22 05:31:30 -04001346 if (displaced)
1347 put_files_struct(displaced);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 return retval;
1349 }
1350
1351out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 if (bprm->security)
1353 security_bprm_free(bprm);
1354
1355out_mm:
1356 if (bprm->mm)
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001357 mmput (bprm->mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358
1359out_file:
1360 if (bprm->file) {
1361 allow_write_access(bprm->file);
1362 fput(bprm->file);
1363 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364out_kfree:
Al Viro08a6fac2008-05-10 16:38:25 -04001365 free_bprm(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366
Al Virofd8328b2008-04-22 05:11:59 -04001367out_files:
Al Viro3b125382008-04-22 05:31:30 -04001368 if (displaced)
1369 reset_files_struct(displaced);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370out_ret:
1371 return retval;
1372}
1373
1374int set_binfmt(struct linux_binfmt *new)
1375{
1376 struct linux_binfmt *old = current->binfmt;
1377
1378 if (new) {
1379 if (!try_module_get(new->module))
1380 return -1;
1381 }
1382 current->binfmt = new;
1383 if (old)
1384 module_put(old->module);
1385 return 0;
1386}
1387
1388EXPORT_SYMBOL(set_binfmt);
1389
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390/* format_corename will inspect the pattern parameter, and output a
1391 * name into corename, which must have space for at least
1392 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1393 */
Oleg Nesterov565b9b12008-07-25 01:47:47 -07001394static int format_corename(char *corename, int nr_threads, long signr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395{
Oleg Nesterov565b9b12008-07-25 01:47:47 -07001396 const char *pat_ptr = core_pattern;
1397 int ispipe = (*pat_ptr == '|');
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 char *out_ptr = corename;
1399 char *const out_end = corename + CORENAME_MAX_SIZE;
1400 int rc;
1401 int pid_in_pattern = 0;
1402
1403 /* Repeat as long as we have more pattern to process and more output
1404 space */
1405 while (*pat_ptr) {
1406 if (*pat_ptr != '%') {
1407 if (out_ptr == out_end)
1408 goto out;
1409 *out_ptr++ = *pat_ptr++;
1410 } else {
1411 switch (*++pat_ptr) {
1412 case 0:
1413 goto out;
1414 /* Double percent, output one percent */
1415 case '%':
1416 if (out_ptr == out_end)
1417 goto out;
1418 *out_ptr++ = '%';
1419 break;
1420 /* pid */
1421 case 'p':
1422 pid_in_pattern = 1;
1423 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001424 "%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425 if (rc > out_end - out_ptr)
1426 goto out;
1427 out_ptr += rc;
1428 break;
1429 /* uid */
1430 case 'u':
1431 rc = snprintf(out_ptr, out_end - out_ptr,
1432 "%d", current->uid);
1433 if (rc > out_end - out_ptr)
1434 goto out;
1435 out_ptr += rc;
1436 break;
1437 /* gid */
1438 case 'g':
1439 rc = snprintf(out_ptr, out_end - out_ptr,
1440 "%d", current->gid);
1441 if (rc > out_end - out_ptr)
1442 goto out;
1443 out_ptr += rc;
1444 break;
1445 /* signal that caused the coredump */
1446 case 's':
1447 rc = snprintf(out_ptr, out_end - out_ptr,
1448 "%ld", signr);
1449 if (rc > out_end - out_ptr)
1450 goto out;
1451 out_ptr += rc;
1452 break;
1453 /* UNIX time of coredump */
1454 case 't': {
1455 struct timeval tv;
1456 do_gettimeofday(&tv);
1457 rc = snprintf(out_ptr, out_end - out_ptr,
1458 "%lu", tv.tv_sec);
1459 if (rc > out_end - out_ptr)
1460 goto out;
1461 out_ptr += rc;
1462 break;
1463 }
1464 /* hostname */
1465 case 'h':
1466 down_read(&uts_sem);
1467 rc = snprintf(out_ptr, out_end - out_ptr,
Serge E. Hallyne9ff3992006-10-02 02:18:11 -07001468 "%s", utsname()->nodename);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 up_read(&uts_sem);
1470 if (rc > out_end - out_ptr)
1471 goto out;
1472 out_ptr += rc;
1473 break;
1474 /* executable */
1475 case 'e':
1476 rc = snprintf(out_ptr, out_end - out_ptr,
1477 "%s", current->comm);
1478 if (rc > out_end - out_ptr)
1479 goto out;
1480 out_ptr += rc;
1481 break;
Neil Horman74aadce2007-10-16 23:26:35 -07001482 /* core limit size */
1483 case 'c':
1484 rc = snprintf(out_ptr, out_end - out_ptr,
1485 "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
1486 if (rc > out_end - out_ptr)
1487 goto out;
1488 out_ptr += rc;
1489 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 default:
1491 break;
1492 }
1493 ++pat_ptr;
1494 }
1495 }
1496 /* Backward compatibility with core_uses_pid:
1497 *
1498 * If core_pattern does not include a %p (as is the default)
1499 * and core_uses_pid is set, then .%pid will be appended to
Alan Coxc4bbafd2007-04-16 22:53:13 -07001500 * the filename. Do not do this for piped commands. */
1501 if (!ispipe && !pid_in_pattern
Oleg Nesterov565b9b12008-07-25 01:47:47 -07001502 && (core_uses_pid || nr_threads)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001503 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001504 ".%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 if (rc > out_end - out_ptr)
1506 goto out;
1507 out_ptr += rc;
1508 }
Alan Coxc4bbafd2007-04-16 22:53:13 -07001509out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 *out_ptr = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001511 return ispipe;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512}
1513
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001514static int zap_process(struct task_struct *start)
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001515{
1516 struct task_struct *t;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001517 int nr = 0;
Oleg Nesterov281de332006-06-26 00:26:06 -07001518
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001519 start->signal->flags = SIGNAL_GROUP_EXIT;
1520 start->signal->group_stop_count = 0;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001521
1522 t = start;
1523 do {
1524 if (t != current && t->mm) {
Oleg Nesterov281de332006-06-26 00:26:06 -07001525 sigaddset(&t->pending.signal, SIGKILL);
1526 signal_wake_up(t, 1);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001527 nr++;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001528 }
Oleg Nesterove4901f92008-07-25 01:47:31 -07001529 } while_each_thread(start, t);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001530
1531 return nr;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001532}
1533
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001534static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001535 struct core_state *core_state, int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536{
1537 struct task_struct *g, *p;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001538 unsigned long flags;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001539 int nr = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001541 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001542 if (!signal_group_exit(tsk->signal)) {
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001543 mm->core_state = core_state;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001544 tsk->signal->group_exit_code = exit_code;
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001545 nr = zap_process(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546 }
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001547 spin_unlock_irq(&tsk->sighand->siglock);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001548 if (unlikely(nr < 0))
1549 return nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001551 if (atomic_read(&mm->mm_users) == nr + 1)
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001552 goto done;
Oleg Nesterove4901f92008-07-25 01:47:31 -07001553 /*
1554 * We should find and kill all tasks which use this mm, and we should
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001555 * count them correctly into ->nr_threads. We don't take tasklist
Oleg Nesterove4901f92008-07-25 01:47:31 -07001556 * lock, but this is safe wrt:
1557 *
1558 * fork:
1559 * None of sub-threads can fork after zap_process(leader). All
1560 * processes which were created before this point should be
1561 * visible to zap_threads() because copy_process() adds the new
1562 * process to the tail of init_task.tasks list, and lock/unlock
1563 * of ->siglock provides a memory barrier.
1564 *
1565 * do_exit:
1566 * The caller holds mm->mmap_sem. This means that the task which
1567 * uses this mm can't pass exit_mm(), so it can't exit or clear
1568 * its ->mm.
1569 *
1570 * de_thread:
1571 * It does list_replace_rcu(&leader->tasks, &current->tasks),
1572 * we must see either old or new leader, this does not matter.
1573 * However, it can change p->sighand, so lock_task_sighand(p)
1574 * must be used. Since p->mm != NULL and we hold ->mmap_sem
1575 * it can't fail.
1576 *
1577 * Note also that "g" can be the old leader with ->mm == NULL
1578 * and already unhashed and thus removed from ->thread_group.
1579 * This is OK, __unhash_process()->list_del_rcu() does not
1580 * clear the ->next pointer, we will find the new leader via
1581 * next_thread().
1582 */
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001583 rcu_read_lock();
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001584 for_each_process(g) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001585 if (g == tsk->group_leader)
1586 continue;
Oleg Nesterov15b9f362008-07-25 01:47:39 -07001587 if (g->flags & PF_KTHREAD)
1588 continue;
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001589 p = g;
1590 do {
1591 if (p->mm) {
Oleg Nesterov15b9f362008-07-25 01:47:39 -07001592 if (unlikely(p->mm == mm)) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001593 lock_task_sighand(p, &flags);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001594 nr += zap_process(p);
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001595 unlock_task_sighand(p, &flags);
1596 }
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001597 break;
1598 }
Oleg Nesterove4901f92008-07-25 01:47:31 -07001599 } while_each_thread(g, p);
Oleg Nesterovaceecc02006-06-26 00:26:05 -07001600 }
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001601 rcu_read_unlock();
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001602done:
Oleg Nesterovc5f1cc82008-07-25 01:47:42 -07001603 atomic_set(&core_state->nr_threads, nr);
Oleg Nesterov8cd9c242008-07-25 01:47:42 -07001604 return nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605}
1606
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001607static int coredump_wait(int exit_code, struct core_state *core_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608{
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001609 struct task_struct *tsk = current;
1610 struct mm_struct *mm = tsk->mm;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001611 struct completion *vfork_done;
Oleg Nesterov2384f552005-10-30 15:02:47 -08001612 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001614 init_completion(&core_state->startup);
Oleg Nesterovb564daf2008-07-25 01:47:44 -07001615 core_state->dumper.task = tsk;
1616 core_state->dumper.next = NULL;
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001617 core_waiters = zap_threads(tsk, mm, core_state, exit_code);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001618 up_write(&mm->mmap_sem);
1619
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001620 if (unlikely(core_waiters < 0))
1621 goto fail;
1622
1623 /*
1624 * Make sure nobody is waiting for us to release the VM,
1625 * otherwise we can deadlock when we wait on each other
1626 */
1627 vfork_done = tsk->vfork_done;
1628 if (vfork_done) {
1629 tsk->vfork_done = NULL;
1630 complete(vfork_done);
1631 }
1632
Oleg Nesterov2384f552005-10-30 15:02:47 -08001633 if (core_waiters)
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001634 wait_for_completion(&core_state->startup);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001635fail:
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001636 return core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637}
1638
Oleg Nesterova94e2d42008-07-25 01:47:46 -07001639static void coredump_finish(struct mm_struct *mm)
1640{
1641 struct core_thread *curr, *next;
1642 struct task_struct *task;
1643
1644 next = mm->core_state->dumper.next;
1645 while ((curr = next) != NULL) {
1646 next = curr->next;
1647 task = curr->task;
1648 /*
1649 * see exit_mm(), curr->task must not see
1650 * ->task == NULL before we read ->next.
1651 */
1652 smp_mb();
1653 curr->task = NULL;
1654 wake_up_process(task);
1655 }
1656
1657 mm->core_state = NULL;
1658}
1659
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001660/*
1661 * set_dumpable converts traditional three-value dumpable to two flags and
1662 * stores them into mm->flags. It modifies lower two bits of mm->flags, but
1663 * these bits are not changed atomically. So get_dumpable can observe the
1664 * intermediate state. To avoid doing unexpected behavior, get get_dumpable
1665 * return either old dumpable or new one by paying attention to the order of
1666 * modifying the bits.
1667 *
1668 * dumpable | mm->flags (binary)
1669 * old new | initial interim final
1670 * ---------+-----------------------
1671 * 0 1 | 00 01 01
1672 * 0 2 | 00 10(*) 11
1673 * 1 0 | 01 00 00
1674 * 1 2 | 01 11 11
1675 * 2 0 | 11 10(*) 00
1676 * 2 1 | 11 11 01
1677 *
1678 * (*) get_dumpable regards interim value of 10 as 11.
1679 */
1680void set_dumpable(struct mm_struct *mm, int value)
1681{
1682 switch (value) {
1683 case 0:
1684 clear_bit(MMF_DUMPABLE, &mm->flags);
1685 smp_wmb();
1686 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1687 break;
1688 case 1:
1689 set_bit(MMF_DUMPABLE, &mm->flags);
1690 smp_wmb();
1691 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1692 break;
1693 case 2:
1694 set_bit(MMF_DUMP_SECURELY, &mm->flags);
1695 smp_wmb();
1696 set_bit(MMF_DUMPABLE, &mm->flags);
1697 break;
1698 }
1699}
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001700
1701int get_dumpable(struct mm_struct *mm)
1702{
1703 int ret;
1704
1705 ret = mm->flags & 0x3;
1706 return (ret >= 2) ? 2 : ret;
1707}
1708
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1710{
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001711 struct core_state core_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712 char corename[CORENAME_MAX_SIZE + 1];
1713 struct mm_struct *mm = current->mm;
1714 struct linux_binfmt * binfmt;
1715 struct inode * inode;
1716 struct file * file;
1717 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001718 int fsuid = current->fsuid;
1719 int flag = 0;
Andi Kleend025c9d2006-09-30 23:29:28 -07001720 int ispipe = 0;
Neil Horman7dc0b222007-10-16 23:26:34 -07001721 unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
Neil Horman74aadce2007-10-16 23:26:35 -07001722 char **helper_argv = NULL;
1723 int helper_argc = 0;
1724 char *delimit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725
Steve Grubb0a4ff8c2007-04-19 10:28:21 -04001726 audit_core_dumps(signr);
1727
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 binfmt = current->binfmt;
1729 if (!binfmt || !binfmt->core_dump)
1730 goto fail;
1731 down_write(&mm->mmap_sem);
Roland McGrath00ec99d2007-11-11 19:13:43 -08001732 /*
1733 * If another thread got here first, or we are not dumpable, bail out.
1734 */
Oleg Nesterov999d9fc2008-07-25 01:47:41 -07001735 if (mm->core_state || !get_dumpable(mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 up_write(&mm->mmap_sem);
1737 goto fail;
1738 }
Alan Coxd6e71142005-06-23 00:09:43 -07001739
1740 /*
1741 * We cannot trust fsuid as being the "true" uid of the
1742 * process nor do we know its entire history. We only know it
1743 * was tainted so we dump it as root in mode 2.
1744 */
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001745 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
Alan Coxd6e71142005-06-23 00:09:43 -07001746 flag = O_EXCL; /* Stop rewrite attacks */
1747 current->fsuid = 0; /* Dump root private */
1748 }
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001749
Oleg Nesterov9d5b3272008-07-25 01:47:43 -07001750 retval = coredump_wait(exit_code, &core_state);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001751 if (retval < 0)
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001752 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753
1754 /*
1755 * Clear any false indication of pending signals that might
1756 * be seen by the filesystem code called to write the core file.
1757 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758 clear_thread_flag(TIF_SIGPENDING);
1759
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 /*
1761 * lock_kernel() because format_corename() is controlled by sysctl, which
1762 * uses lock_kernel()
1763 */
1764 lock_kernel();
Oleg Nesterov565b9b12008-07-25 01:47:47 -07001765 ispipe = format_corename(corename, retval, signr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 unlock_kernel();
Neil Horman7dc0b222007-10-16 23:26:34 -07001767 /*
1768 * Don't bother to check the RLIMIT_CORE value if core_pattern points
1769 * to a pipe. Since we're not writing directly to the filesystem
1770 * RLIMIT_CORE doesn't really apply, as no actual core file will be
1771 * created unless the pipe reader choses to write out the core file
1772 * at which point file size limits and permissions will be imposed
1773 * as it does with any other process
1774 */
Neil Horman74aadce2007-10-16 23:26:35 -07001775 if ((!ispipe) && (core_limit < binfmt->min_coredump))
Neil Horman7dc0b222007-10-16 23:26:34 -07001776 goto fail_unlock;
1777
Alan Coxc4bbafd2007-04-16 22:53:13 -07001778 if (ispipe) {
Neil Horman74aadce2007-10-16 23:26:35 -07001779 helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
1780 /* Terminate the string before the first option */
1781 delimit = strchr(corename, ' ');
1782 if (delimit)
1783 *delimit = '\0';
Neil Horman32321132007-10-16 23:26:36 -07001784 delimit = strrchr(helper_argv[0], '/');
1785 if (delimit)
1786 delimit++;
1787 else
1788 delimit = helper_argv[0];
1789 if (!strcmp(delimit, current->comm)) {
1790 printk(KERN_NOTICE "Recursive core dump detected, "
1791 "aborting\n");
1792 goto fail_unlock;
1793 }
1794
1795 core_limit = RLIM_INFINITY;
1796
Andi Kleend025c9d2006-09-30 23:29:28 -07001797 /* SIGPIPE can happen, but it's just never processed */
Neil Horman32321132007-10-16 23:26:36 -07001798 if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
1799 &file)) {
Andi Kleend025c9d2006-09-30 23:29:28 -07001800 printk(KERN_INFO "Core dump to %s pipe failed\n",
1801 corename);
1802 goto fail_unlock;
1803 }
Andi Kleend025c9d2006-09-30 23:29:28 -07001804 } else
1805 file = filp_open(corename,
Alexey Dobriyan6d4df672006-12-06 20:40:39 -08001806 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1807 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 if (IS_ERR(file))
1809 goto fail_unlock;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001810 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811 if (inode->i_nlink > 1)
1812 goto close_fail; /* multiple links - don't dump */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001813 if (!ispipe && d_unhashed(file->f_path.dentry))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 goto close_fail;
1815
Andi Kleend025c9d2006-09-30 23:29:28 -07001816 /* AK: actually i see no reason to not allow this for named pipes etc.,
1817 but keep the previous behaviour for now. */
1818 if (!ispipe && !S_ISREG(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 goto close_fail;
Ingo Molnarc46f7392007-11-28 13:59:18 +01001820 /*
1821 * Dont allow local users get cute and trick others to coredump
1822 * into their pre-created files:
1823 */
1824 if (inode->i_uid != current->fsuid)
1825 goto close_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 if (!file->f_op)
1827 goto close_fail;
1828 if (!file->f_op->write)
1829 goto close_fail;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001830 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 goto close_fail;
1832
Neil Horman7dc0b222007-10-16 23:26:34 -07001833 retval = binfmt->core_dump(signr, regs, file, core_limit);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834
1835 if (retval)
1836 current->signal->group_exit_code |= 0x80;
1837close_fail:
1838 filp_close(file, NULL);
1839fail_unlock:
Neil Horman74aadce2007-10-16 23:26:35 -07001840 if (helper_argv)
1841 argv_free(helper_argv);
1842
Alan Coxd6e71142005-06-23 00:09:43 -07001843 current->fsuid = fsuid;
Oleg Nesterova94e2d42008-07-25 01:47:46 -07001844 coredump_finish(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845fail:
1846 return retval;
1847}