blob: 9448f1b50b4a07a8969d8587d044094bbfcfce8a [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/mman.h>
29#include <linux/a.out.h>
30#include <linux/stat.h>
31#include <linux/fcntl.h>
32#include <linux/smp_lock.h>
Neil Horman74aadce2007-10-16 23:26:35 -070033#include <linux/string.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/init.h>
35#include <linux/pagemap.h>
36#include <linux/highmem.h>
37#include <linux/spinlock.h>
38#include <linux/key.h>
39#include <linux/personality.h>
40#include <linux/binfmts.h>
41#include <linux/swap.h>
42#include <linux/utsname.h>
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>
47#include <linux/ptrace.h>
48#include <linux/mount.h>
49#include <linux/security.h>
50#include <linux/syscalls.h>
51#include <linux/rmap.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070052#include <linux/tsacct_kern.h>
Matt Helsley9f460802005-11-07 00:59:16 -080053#include <linux/cn_proc.h>
Al Viro473ae302006-04-26 14:04:08 -040054#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56#include <asm/uaccess.h>
57#include <asm/mmu_context.h>
Ollie Wildb6a2fea2007-07-19 01:48:16 -070058#include <asm/tlb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60#ifdef CONFIG_KMOD
61#include <linux/kmod.h>
62#endif
63
64int 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
73int register_binfmt(struct linux_binfmt * fmt)
74{
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);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070078 list_add(&fmt->lh, &formats);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 write_unlock(&binfmt_lock);
80 return 0;
81}
82
83EXPORT_SYMBOL(register_binfmt);
84
Alexey Dobriyanf6b450d2007-10-16 23:26:04 -070085void unregister_binfmt(struct linux_binfmt * fmt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086{
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 write_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -070088 list_del(&fmt->lh);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 write_unlock(&binfmt_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090}
91
92EXPORT_SYMBOL(unregister_binfmt);
93
94static inline void put_binfmt(struct linux_binfmt * fmt)
95{
96 module_put(fmt->module);
97}
98
99/*
100 * Note that a shared library must be both readable and executable due to
101 * security reasons.
102 *
103 * Also note that we take the address to load from from the file itself.
104 */
105asmlinkage long sys_uselib(const char __user * library)
106{
107 struct file * file;
108 struct nameidata nd;
109 int error;
110
Oleg Drokinb5005312006-03-25 03:07:01 -0800111 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 if (error)
113 goto out;
114
115 error = -EINVAL;
Jan Blunck4ac91372008-02-14 19:34:32 -0800116 if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 goto exit;
118
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800119 error = vfs_permission(&nd, MAY_READ | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 if (error)
121 goto exit;
122
Andi Kleenabe8be32008-02-08 04:20:23 -0800123 file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 error = PTR_ERR(file);
125 if (IS_ERR(file))
126 goto out;
127
128 error = -ENOEXEC;
129 if(file->f_op) {
130 struct linux_binfmt * fmt;
131
132 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -0700133 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 if (!fmt->load_shlib)
135 continue;
136 if (!try_module_get(fmt->module))
137 continue;
138 read_unlock(&binfmt_lock);
139 error = fmt->load_shlib(file);
140 read_lock(&binfmt_lock);
141 put_binfmt(fmt);
142 if (error != -ENOEXEC)
143 break;
144 }
145 read_unlock(&binfmt_lock);
146 }
147 fput(file);
148out:
149 return error;
150exit:
Trond Myklebust834f2a42005-10-18 14:20:16 -0700151 release_open_intent(&nd);
Jan Blunck1d957f92008-02-14 19:34:35 -0800152 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 goto out;
154}
155
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700156#ifdef CONFIG_MMU
157
158static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
159 int write)
160{
161 struct page *page;
162 int ret;
163
164#ifdef CONFIG_STACK_GROWSUP
165 if (write) {
166 ret = expand_stack_downwards(bprm->vma, pos);
167 if (ret < 0)
168 return NULL;
169 }
170#endif
171 ret = get_user_pages(current, bprm->mm, pos,
172 1, write, 1, &page, NULL);
173 if (ret <= 0)
174 return NULL;
175
176 if (write) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700177 unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800178 struct rlimit *rlim;
179
180 /*
181 * We've historically supported up to 32 pages (ARG_MAX)
182 * of argument strings even with small stacks
183 */
184 if (size <= ARG_MAX)
185 return page;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700186
187 /*
188 * Limit to 1/4-th the stack size for the argv+env strings.
189 * This ensures that:
190 * - the remaining binfmt code will not run out of stack space,
191 * - the program will have a reasonable amount of stack left
192 * to work from.
193 */
Linus Torvaldsa64e7152008-03-03 10:12:14 -0800194 rlim = current->signal->rlim;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700195 if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
196 put_page(page);
197 return NULL;
198 }
199 }
200
201 return page;
202}
203
204static void put_arg_page(struct page *page)
205{
206 put_page(page);
207}
208
209static void free_arg_page(struct linux_binprm *bprm, int i)
210{
211}
212
213static void free_arg_pages(struct linux_binprm *bprm)
214{
215}
216
217static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
218 struct page *page)
219{
220 flush_cache_page(bprm->vma, pos, page_to_pfn(page));
221}
222
223static int __bprm_mm_init(struct linux_binprm *bprm)
224{
225 int err = -ENOMEM;
226 struct vm_area_struct *vma = NULL;
227 struct mm_struct *mm = bprm->mm;
228
229 bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
230 if (!vma)
231 goto err;
232
233 down_write(&mm->mmap_sem);
234 vma->vm_mm = mm;
235
236 /*
237 * Place the stack at the largest stack address the architecture
238 * supports. Later, we'll move this to an appropriate place. We don't
239 * use STACK_TOP because that can depend on attributes which aren't
240 * configured yet.
241 */
242 vma->vm_end = STACK_TOP_MAX;
243 vma->vm_start = vma->vm_end - PAGE_SIZE;
244
245 vma->vm_flags = VM_STACK_FLAGS;
Coly Li3ed75eb2007-10-18 23:39:15 -0700246 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700247 err = insert_vm_struct(mm, vma);
248 if (err) {
249 up_write(&mm->mmap_sem);
250 goto err;
251 }
252
253 mm->stack_vm = mm->total_vm = 1;
254 up_write(&mm->mmap_sem);
255
256 bprm->p = vma->vm_end - sizeof(void *);
257
258 return 0;
259
260err:
261 if (vma) {
262 bprm->vma = NULL;
263 kmem_cache_free(vm_area_cachep, vma);
264 }
265
266 return err;
267}
268
269static bool valid_arg_len(struct linux_binprm *bprm, long len)
270{
271 return len <= MAX_ARG_STRLEN;
272}
273
274#else
275
276static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
277 int write)
278{
279 struct page *page;
280
281 page = bprm->page[pos / PAGE_SIZE];
282 if (!page && write) {
283 page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
284 if (!page)
285 return NULL;
286 bprm->page[pos / PAGE_SIZE] = page;
287 }
288
289 return page;
290}
291
292static void put_arg_page(struct page *page)
293{
294}
295
296static void free_arg_page(struct linux_binprm *bprm, int i)
297{
298 if (bprm->page[i]) {
299 __free_page(bprm->page[i]);
300 bprm->page[i] = NULL;
301 }
302}
303
304static void free_arg_pages(struct linux_binprm *bprm)
305{
306 int i;
307
308 for (i = 0; i < MAX_ARG_PAGES; i++)
309 free_arg_page(bprm, i);
310}
311
312static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
313 struct page *page)
314{
315}
316
317static int __bprm_mm_init(struct linux_binprm *bprm)
318{
319 bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
320 return 0;
321}
322
323static bool valid_arg_len(struct linux_binprm *bprm, long len)
324{
325 return len <= bprm->p;
326}
327
328#endif /* CONFIG_MMU */
329
330/*
331 * Create a new mm_struct and populate it with a temporary stack
332 * vm_area_struct. We don't have enough context at this point to set the stack
333 * flags, permissions, and offset, so we use temporary values. We'll update
334 * them later in setup_arg_pages().
335 */
336int bprm_mm_init(struct linux_binprm *bprm)
337{
338 int err;
339 struct mm_struct *mm = NULL;
340
341 bprm->mm = mm = mm_alloc();
342 err = -ENOMEM;
343 if (!mm)
344 goto err;
345
346 err = init_new_context(current, mm);
347 if (err)
348 goto err;
349
350 err = __bprm_mm_init(bprm);
351 if (err)
352 goto err;
353
354 return 0;
355
356err:
357 if (mm) {
358 bprm->mm = NULL;
359 mmdrop(mm);
360 }
361
362 return err;
363}
364
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365/*
366 * count() counts the number of strings in array ARGV.
367 */
368static int count(char __user * __user * argv, int max)
369{
370 int i = 0;
371
372 if (argv != NULL) {
373 for (;;) {
374 char __user * p;
375
376 if (get_user(p, argv))
377 return -EFAULT;
378 if (!p)
379 break;
380 argv++;
381 if(++i > max)
382 return -E2BIG;
383 cond_resched();
384 }
385 }
386 return i;
387}
388
389/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700390 * 'copy_strings()' copies argument/environment strings from the old
391 * processes's memory to the new process's stack. The call to get_user_pages()
392 * ensures the destination page is created and not swapped out.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700394static int copy_strings(int argc, char __user * __user * argv,
395 struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396{
397 struct page *kmapped_page = NULL;
398 char *kaddr = NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700399 unsigned long kpos = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 int ret;
401
402 while (argc-- > 0) {
403 char __user *str;
404 int len;
405 unsigned long pos;
406
407 if (get_user(str, argv+argc) ||
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700408 !(len = strnlen_user(str, MAX_ARG_STRLEN))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 ret = -EFAULT;
410 goto out;
411 }
412
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700413 if (!valid_arg_len(bprm, len)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 ret = -E2BIG;
415 goto out;
416 }
417
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700418 /* We're going to work our way backwords. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 pos = bprm->p;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700420 str += len;
421 bprm->p -= len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
423 while (len > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 int offset, bytes_to_copy;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
426 offset = pos % PAGE_SIZE;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700427 if (offset == 0)
428 offset = PAGE_SIZE;
429
430 bytes_to_copy = offset;
431 if (bytes_to_copy > len)
432 bytes_to_copy = len;
433
434 offset -= bytes_to_copy;
435 pos -= bytes_to_copy;
436 str -= bytes_to_copy;
437 len -= bytes_to_copy;
438
439 if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
440 struct page *page;
441
442 page = get_arg_page(bprm, pos, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 if (!page) {
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700444 ret = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 goto out;
446 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700448 if (kmapped_page) {
449 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700451 put_arg_page(kmapped_page);
452 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 kmapped_page = page;
454 kaddr = kmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700455 kpos = pos & PAGE_MASK;
456 flush_arg_page(bprm, kpos, kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700458 if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 ret = -EFAULT;
460 goto out;
461 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 }
463 }
464 ret = 0;
465out:
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700466 if (kmapped_page) {
467 flush_kernel_dcache_page(kmapped_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 kunmap(kmapped_page);
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700469 put_arg_page(kmapped_page);
470 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 return ret;
472}
473
474/*
475 * Like copy_strings, but get argv and its values from kernel memory.
476 */
477int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
478{
479 int r;
480 mm_segment_t oldfs = get_fs();
481 set_fs(KERNEL_DS);
482 r = copy_strings(argc, (char __user * __user *)argv, bprm);
483 set_fs(oldfs);
484 return r;
485}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486EXPORT_SYMBOL(copy_strings_kernel);
487
488#ifdef CONFIG_MMU
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490/*
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700491 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once
492 * the binfmt code determines where the new stack should reside, we shift it to
493 * its final location. The process proceeds as follows:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 *
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700495 * 1) Use shift to calculate the new vma endpoints.
496 * 2) Extend vma to cover both the old and new ranges. This ensures the
497 * arguments passed to subsequent functions are consistent.
498 * 3) Move vma's page tables to the new range.
499 * 4) Free up any cleared pgd range.
500 * 5) Shrink the vma to cover only the new range.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700502static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503{
504 struct mm_struct *mm = vma->vm_mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700505 unsigned long old_start = vma->vm_start;
506 unsigned long old_end = vma->vm_end;
507 unsigned long length = old_end - old_start;
508 unsigned long new_start = old_start - shift;
509 unsigned long new_end = old_end - shift;
510 struct mmu_gather *tlb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700512 BUG_ON(new_start > new_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700514 /*
515 * ensure there are no vmas between where we want to go
516 * and where we are
517 */
518 if (vma != find_vma(mm, new_start))
519 return -EFAULT;
520
521 /*
522 * cover the whole range: [new_start, old_end)
523 */
524 vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL);
525
526 /*
527 * move the page tables downwards, on failure we rely on
528 * process cleanup to remove whatever mess we made.
529 */
530 if (length != move_page_tables(vma, old_start,
531 vma, new_start, length))
532 return -ENOMEM;
533
534 lru_add_drain();
535 tlb = tlb_gather_mmu(mm, 0);
536 if (new_end > old_start) {
537 /*
538 * when the old and new regions overlap clear from new_end.
539 */
540 free_pgd_range(&tlb, new_end, old_end, new_end,
541 vma->vm_next ? vma->vm_next->vm_start : 0);
542 } else {
543 /*
544 * otherwise, clean from old_start; this is done to not touch
545 * the address space in [new_end, old_start) some architectures
546 * have constraints on va-space that make this illegal (IA64) -
547 * for the others its just a little faster.
548 */
549 free_pgd_range(&tlb, old_start, old_end, new_end,
550 vma->vm_next ? vma->vm_next->vm_start : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 }
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700552 tlb_finish_mmu(tlb, new_end, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700554 /*
555 * shrink the vma to just the new range.
556 */
557 vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
558
559 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560}
561
562#define EXTRA_STACK_VM_PAGES 20 /* random */
563
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700564/*
565 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
566 * the stack is optionally relocated, and some extra space is added.
567 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568int setup_arg_pages(struct linux_binprm *bprm,
569 unsigned long stack_top,
570 int executable_stack)
571{
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700572 unsigned long ret;
573 unsigned long stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 struct mm_struct *mm = current->mm;
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700575 struct vm_area_struct *vma = bprm->vma;
576 struct vm_area_struct *prev = NULL;
577 unsigned long vm_flags;
578 unsigned long stack_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579
580#ifdef CONFIG_STACK_GROWSUP
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 /* Limit stack size to 1GB */
582 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
583 if (stack_base > (1 << 30))
584 stack_base = 1 << 30;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700586 /* Make sure we didn't let the argument array grow too large. */
587 if (vma->vm_end - vma->vm_start > stack_base)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 return -ENOMEM;
589
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700590 stack_base = PAGE_ALIGN(stack_top - stack_base);
591
592 stack_shift = vma->vm_start - stack_base;
593 mm->arg_start = bprm->p - stack_shift;
594 bprm->p = vma->vm_end - stack_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595#else
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700596 stack_top = arch_align_stack(stack_top);
597 stack_top = PAGE_ALIGN(stack_top);
598 stack_shift = vma->vm_end - stack_top;
599
600 bprm->p -= stack_shift;
601 mm->arg_start = bprm->p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602#endif
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700603
604 if (bprm->loader)
605 bprm->loader -= stack_shift;
606 bprm->exec -= stack_shift;
607
608 down_write(&mm->mmap_sem);
609 vm_flags = vma->vm_flags;
610
611 /*
612 * Adjust stack execute permissions; explicitly enable for
613 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
614 * (arch default) otherwise.
615 */
616 if (unlikely(executable_stack == EXSTACK_ENABLE_X))
617 vm_flags |= VM_EXEC;
618 else if (executable_stack == EXSTACK_DISABLE_X)
619 vm_flags &= ~VM_EXEC;
620 vm_flags |= mm->def_flags;
621
622 ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
623 vm_flags);
624 if (ret)
625 goto out_unlock;
626 BUG_ON(prev != vma);
627
628 /* Move stack pages down in memory. */
629 if (stack_shift) {
630 ret = shift_arg_pages(vma, stack_shift);
631 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return ret;
634 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 }
636
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700637#ifdef CONFIG_STACK_GROWSUP
638 stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE;
639#else
640 stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE;
641#endif
642 ret = expand_stack(vma, stack_base);
643 if (ret)
644 ret = -EFAULT;
645
646out_unlock:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 up_write(&mm->mmap_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 return 0;
649}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650EXPORT_SYMBOL(setup_arg_pages);
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652#endif /* CONFIG_MMU */
653
654struct file *open_exec(const char *name)
655{
656 struct nameidata nd;
657 int err;
658 struct file *file;
659
Oleg Drokinb5005312006-03-25 03:07:01 -0800660 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 file = ERR_PTR(err);
662
663 if (!err) {
Jan Blunck4ac91372008-02-14 19:34:32 -0800664 struct inode *inode = nd.path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 file = ERR_PTR(-EACCES);
Miklos Szeredi1a159dd2007-10-16 23:27:08 -0700666 if (S_ISREG(inode->i_mode)) {
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800667 int err = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 file = ERR_PTR(err);
669 if (!err) {
Andi Kleenabe8be32008-02-08 04:20:23 -0800670 file = nameidata_to_filp(&nd,
671 O_RDONLY|O_LARGEFILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 if (!IS_ERR(file)) {
673 err = deny_write_access(file);
674 if (err) {
675 fput(file);
676 file = ERR_PTR(err);
677 }
678 }
679out:
680 return file;
681 }
682 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700683 release_open_intent(&nd);
Jan Blunck1d957f92008-02-14 19:34:35 -0800684 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 }
686 goto out;
687}
688
689EXPORT_SYMBOL(open_exec);
690
691int kernel_read(struct file *file, unsigned long offset,
692 char *addr, unsigned long count)
693{
694 mm_segment_t old_fs;
695 loff_t pos = offset;
696 int result;
697
698 old_fs = get_fs();
699 set_fs(get_ds());
700 /* The cast to a user pointer is valid due to the set_fs() */
701 result = vfs_read(file, (void __user *)addr, count, &pos);
702 set_fs(old_fs);
703 return result;
704}
705
706EXPORT_SYMBOL(kernel_read);
707
708static int exec_mmap(struct mm_struct *mm)
709{
710 struct task_struct *tsk;
711 struct mm_struct * old_mm, *active_mm;
712
713 /* Notify parent that we're no longer interested in the old VM */
714 tsk = current;
715 old_mm = current->mm;
716 mm_release(tsk, old_mm);
717
718 if (old_mm) {
719 /*
720 * Make sure that if there is a core dump in progress
721 * for the old mm, we get out and die instead of going
722 * through with the exec. We must hold mmap_sem around
723 * checking core_waiters and changing tsk->mm. The
724 * core-inducing thread will increment core_waiters for
725 * each thread whose ->mm == old_mm.
726 */
727 down_read(&old_mm->mmap_sem);
728 if (unlikely(old_mm->core_waiters)) {
729 up_read(&old_mm->mmap_sem);
730 return -EINTR;
731 }
732 }
733 task_lock(tsk);
734 active_mm = tsk->active_mm;
735 tsk->mm = mm;
736 tsk->active_mm = mm;
737 activate_mm(active_mm, mm);
738 task_unlock(tsk);
KOSAKI Motohiro4cd1a8f2008-05-12 14:02:31 -0700739 mm_update_next_owner(old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 arch_pick_mmap_layout(mm);
741 if (old_mm) {
742 up_read(&old_mm->mmap_sem);
Eric Sesterhenn7dddb122006-04-01 01:13:38 +0200743 BUG_ON(active_mm != old_mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 mmput(old_mm);
745 return 0;
746 }
747 mmdrop(active_mm);
748 return 0;
749}
750
751/*
752 * This function makes sure the current process has its own signal table,
753 * so that flush_signal_handlers can later reset the handlers without
754 * disturbing other processes. (Other processes might share the signal
755 * table via the CLONE_SIGHAND option to clone().)
756 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800757static int de_thread(struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758{
759 struct signal_struct *sig = tsk->signal;
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700760 struct sighand_struct *oldsighand = tsk->sighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 spinlock_t *lock = &oldsighand->siglock;
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300762 struct task_struct *leader = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 int count;
764
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700765 if (thread_group_empty(tsk))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 goto no_thread_group;
767
768 /*
769 * Kill all other threads in the thread group.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 spin_lock_irq(lock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800772 if (signal_group_exit(sig)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 /*
774 * Another group action in progress, just
775 * return so that the signal is processed.
776 */
777 spin_unlock_irq(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 return -EAGAIN;
779 }
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800780 sig->group_exit_task = tsk;
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700781 zap_other_threads(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782
Oleg Nesterovfea9d172008-02-08 04:19:19 -0800783 /* Account for the thread group leader hanging around: */
784 count = thread_group_leader(tsk) ? 1 : 2;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700785 sig->notify_count = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 while (atomic_read(&sig->count) > count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 __set_current_state(TASK_UNINTERRUPTIBLE);
788 spin_unlock_irq(lock);
789 schedule();
790 spin_lock_irq(lock);
791 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 spin_unlock_irq(lock);
793
794 /*
795 * At this point all other threads have exited, all we have to
796 * do is to wait for the thread group leader to become inactive,
797 * and to assume its PID:
798 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700799 if (!thread_group_leader(tsk)) {
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700800 leader = tsk->group_leader;
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700801
Oleg Nesterov2800d8d2008-04-30 00:53:12 -0700802 sig->notify_count = -1; /* for exit_notify() */
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700803 for (;;) {
804 write_lock_irq(&tasklist_lock);
805 if (likely(leader->exit_state))
806 break;
807 __set_current_state(TASK_UNINTERRUPTIBLE);
808 write_unlock_irq(&tasklist_lock);
809 schedule();
810 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
Oleg Nesterov7a5e8732008-04-30 00:53:04 -0700812 if (unlikely(task_child_reaper(tsk) == leader))
813 task_active_pid_ns(tsk)->child_reaper = tsk;
Roland McGrathf5e90282006-04-10 22:54:16 -0700814 /*
815 * The only record we have of the real-time age of a
816 * process, regardless of execs it's done, is start_time.
817 * All the past CPU time is accumulated in signal_struct
818 * from sister threads now dead. But in this non-leader
819 * exec, nothing survives from the original leader thread,
820 * whose birth marks the true age of this process now.
821 * When we take on its identity by switching to its PID, we
822 * also take its birthdate (always earlier than our own).
823 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700824 tsk->start_time = leader->start_time;
Roland McGrathf5e90282006-04-10 22:54:16 -0700825
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700826 BUG_ON(!same_thread_group(leader, tsk));
827 BUG_ON(has_group_leader_pid(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 /*
829 * An exec() starts a new thread group with the
830 * TGID of the previous thread group. Rehash the
831 * two threads with a switched PID, and release
832 * the former thread group leader:
833 */
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800834
835 /* Become a process group leader with the old leader's pid.
Eric W. Biedermanc18258c2006-09-27 01:51:06 -0700836 * The old leader becomes a thread of the this thread group.
837 * Note: The old leader also uses this pid until release_task
Eric W. Biedermand73d6522006-03-28 16:11:03 -0800838 * is called. Odd but simple and correct.
839 */
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700840 detach_pid(tsk, PIDTYPE_PID);
841 tsk->pid = leader->pid;
Sukadev Bhattiprolu3743ca02007-10-18 23:39:51 -0700842 attach_pid(tsk, PIDTYPE_PID, task_pid(leader));
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700843 transfer_pid(leader, tsk, PIDTYPE_PGID);
844 transfer_pid(leader, tsk, PIDTYPE_SID);
845 list_replace_rcu(&leader->tasks, &tsk->tasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700847 tsk->group_leader = tsk;
848 leader->group_leader = tsk;
Eric W. Biedermande12a782006-04-10 17:16:49 -0600849
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700850 tsk->exit_signal = SIGCHLD;
Oleg Nesterov962b5642005-11-23 13:37:43 -0800851
852 BUG_ON(leader->exit_state != EXIT_ZOMBIE);
853 leader->exit_state = EXIT_DEAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
855 write_unlock_irq(&tasklist_lock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -0800856 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857
Oleg Nesterov6db840f2007-10-16 23:27:23 -0700858 sig->group_exit_task = NULL;
859 sig->notify_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860
861no_thread_group:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 exit_itimers(sig);
Oleg Nesterovcbaffba2008-05-26 20:55:42 +0400863 flush_itimer_signals();
Oleg Nesterov329f7db2005-11-07 21:12:43 +0300864 if (leader)
865 release_task(leader);
866
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700867 if (atomic_read(&oldsighand->count) != 1) {
868 struct sighand_struct *newsighand;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 /*
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700870 * This ->sighand is shared with the CLONE_SIGHAND
871 * but not CLONE_THREAD task, switch to the new one.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 */
Oleg Nesterovb2c903b2007-10-16 23:27:22 -0700873 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
874 if (!newsighand)
875 return -ENOMEM;
876
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 atomic_set(&newsighand->count, 1);
878 memcpy(newsighand->action, oldsighand->action,
879 sizeof(newsighand->action));
880
881 write_lock_irq(&tasklist_lock);
882 spin_lock(&oldsighand->siglock);
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700883 rcu_assign_pointer(tsk->sighand, newsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 spin_unlock(&oldsighand->siglock);
885 write_unlock_irq(&tasklist_lock);
886
Davide Libenzifba2afa2007-05-10 22:23:13 -0700887 __cleanup_sighand(oldsighand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 }
889
Eric W. Biedermanaafe6c22006-09-27 01:51:13 -0700890 BUG_ON(!thread_group_leader(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 return 0;
892}
Oleg Nesterov0840a902007-10-16 23:27:22 -0700893
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894/*
895 * These functions flushes out all traces of the currently running executable
896 * so that a new one can be started
897 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800898static void flush_old_files(struct files_struct * files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899{
900 long j = -1;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700901 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902
903 spin_lock(&files->file_lock);
904 for (;;) {
905 unsigned long set, i;
906
907 j++;
908 i = j * __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700909 fdt = files_fdtable(files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800910 if (i >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 break;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700912 set = fdt->close_on_exec->fds_bits[j];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 if (!set)
914 continue;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700915 fdt->close_on_exec->fds_bits[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 spin_unlock(&files->file_lock);
917 for ( ; set ; i++,set >>= 1) {
918 if (set & 1) {
919 sys_close(i);
920 }
921 }
922 spin_lock(&files->file_lock);
923
924 }
925 spin_unlock(&files->file_lock);
926}
927
Andrew Morton59714d62008-02-04 22:27:21 -0800928char *get_task_comm(char *buf, struct task_struct *tsk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929{
930 /* buf must be at least sizeof(tsk->comm) in size */
931 task_lock(tsk);
932 strncpy(buf, tsk->comm, sizeof(tsk->comm));
933 task_unlock(tsk);
Andrew Morton59714d62008-02-04 22:27:21 -0800934 return buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935}
936
937void set_task_comm(struct task_struct *tsk, char *buf)
938{
939 task_lock(tsk);
940 strlcpy(tsk->comm, buf, sizeof(tsk->comm));
941 task_unlock(tsk);
942}
943
944int flush_old_exec(struct linux_binprm * bprm)
945{
946 char * name;
947 int i, ch, retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 char tcomm[sizeof(current->comm)];
949
950 /*
951 * Make sure we have a private signal table and that
952 * we are unassociated from the previous thread group.
953 */
954 retval = de_thread(current);
955 if (retval)
956 goto out;
957
Matt Helsley925d1c42008-04-29 01:01:36 -0700958 set_mm_exe_file(bprm->mm, bprm->file);
959
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 * Release all of the old mmap stuff
962 */
963 retval = exec_mmap(bprm->mm);
964 if (retval)
Al Virofd8328b2008-04-22 05:11:59 -0400965 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966
967 bprm->mm = NULL; /* We're using it now */
968
969 /* This is the point of no return */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 current->sas_ss_sp = current->sas_ss_size = 0;
971
972 if (current->euid == current->uid && current->egid == current->gid)
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700973 set_dumpable(current->mm, 1);
Alan Coxd6e71142005-06-23 00:09:43 -0700974 else
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700975 set_dumpable(current->mm, suid_dumpable);
Alan Coxd6e71142005-06-23 00:09:43 -0700976
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 name = bprm->filename;
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700978
979 /* Copies the binary name from after last slash */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 for (i=0; (ch = *(name++)) != '\0';) {
981 if (ch == '/')
Paolo 'Blaisorblade' Giarrusso36772092005-05-05 16:16:12 -0700982 i = 0; /* overwrite what we wrote */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 else
984 if (i < (sizeof(tcomm) - 1))
985 tcomm[i++] = ch;
986 }
987 tcomm[i] = '\0';
988 set_task_comm(current, tcomm);
989
990 current->flags &= ~PF_RANDOMIZE;
991 flush_thread();
992
Benjamin Herrenschmidt0551fbd2006-02-28 16:59:19 -0800993 /* Set the new mm task size. We have to do that late because it may
994 * depend on TIF_32BIT which is only updated in flush_thread() on
995 * some architectures like powerpc
996 */
997 current->mm->task_size = TASK_SIZE;
998
Marcel Holtmannd2d56c52007-08-17 21:47:58 +0200999 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) {
1000 suid_keys(current);
1001 set_dumpable(current->mm, suid_dumpable);
1002 current->pdeath_signal = 0;
1003 } else if (file_permission(bprm->file, MAY_READ) ||
1004 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 suid_keys(current);
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001006 set_dumpable(current->mm, suid_dumpable);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 }
1008
1009 /* An exec changes our domain. We are no longer part of the thread
1010 group */
1011
1012 current->self_exec_id++;
1013
1014 flush_signal_handlers(current, 0);
1015 flush_old_files(current->files);
1016
1017 return 0;
1018
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019out:
1020 return retval;
1021}
1022
1023EXPORT_SYMBOL(flush_old_exec);
1024
1025/*
1026 * Fill the binprm structure from the inode.
1027 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
1028 */
1029int prepare_binprm(struct linux_binprm *bprm)
1030{
1031 int mode;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001032 struct inode * inode = bprm->file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 int retval;
1034
1035 mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 if (bprm->file->f_op == NULL)
1037 return -EACCES;
1038
1039 bprm->e_uid = current->euid;
1040 bprm->e_gid = current->egid;
1041
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001042 if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 /* Set-uid? */
1044 if (mode & S_ISUID) {
1045 current->personality &= ~PER_CLEAR_ON_SETID;
1046 bprm->e_uid = inode->i_uid;
1047 }
1048
1049 /* Set-gid? */
1050 /*
1051 * If setgid is set but no group execute bit then this
1052 * is a candidate for mandatory locking, not a setgid
1053 * executable.
1054 */
1055 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1056 current->personality &= ~PER_CLEAR_ON_SETID;
1057 bprm->e_gid = inode->i_gid;
1058 }
1059 }
1060
1061 /* fill in binprm security blob */
1062 retval = security_bprm_set(bprm);
1063 if (retval)
1064 return retval;
1065
1066 memset(bprm->buf,0,BINPRM_BUF_SIZE);
1067 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
1068}
1069
1070EXPORT_SYMBOL(prepare_binprm);
1071
Arjan van de Ven858119e2006-01-14 13:20:43 -08001072static int unsafe_exec(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073{
1074 int unsafe = 0;
1075 if (p->ptrace & PT_PTRACED) {
1076 if (p->ptrace & PT_PTRACE_CAP)
1077 unsafe |= LSM_UNSAFE_PTRACE_CAP;
1078 else
1079 unsafe |= LSM_UNSAFE_PTRACE;
1080 }
1081 if (atomic_read(&p->fs->count) > 1 ||
1082 atomic_read(&p->files->count) > 1 ||
1083 atomic_read(&p->sighand->count) > 1)
1084 unsafe |= LSM_UNSAFE_SHARE;
1085
1086 return unsafe;
1087}
1088
1089void compute_creds(struct linux_binprm *bprm)
1090{
1091 int unsafe;
1092
Marcel Holtmannd2d56c52007-08-17 21:47:58 +02001093 if (bprm->e_uid != current->uid) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 suid_keys(current);
Marcel Holtmannd2d56c52007-08-17 21:47:58 +02001095 current->pdeath_signal = 0;
1096 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 exec_keys(current);
1098
1099 task_lock(current);
1100 unsafe = unsafe_exec(current);
1101 security_bprm_apply_creds(bprm, unsafe);
1102 task_unlock(current);
1103 security_bprm_post_apply_creds(bprm);
1104}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105EXPORT_SYMBOL(compute_creds);
1106
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001107/*
1108 * Arguments are '\0' separated strings found at the location bprm->p
1109 * points to; chop off the first by relocating brpm->p to right after
1110 * the first '\0' encountered.
1111 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001112int remove_arg_zero(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113{
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001114 int ret = 0;
1115 unsigned long offset;
1116 char *kaddr;
1117 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001119 if (!bprm->argc)
1120 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001122 do {
1123 offset = bprm->p & ~PAGE_MASK;
1124 page = get_arg_page(bprm, bprm->p, 0);
1125 if (!page) {
1126 ret = -EFAULT;
1127 goto out;
1128 }
1129 kaddr = kmap_atomic(page, KM_USER0);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001130
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001131 for (; offset < PAGE_SIZE && kaddr[offset];
1132 offset++, bprm->p++)
1133 ;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001134
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001135 kunmap_atomic(kaddr, KM_USER0);
1136 put_arg_page(page);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001137
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001138 if (offset == PAGE_SIZE)
1139 free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
1140 } while (offset == PAGE_SIZE);
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001141
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001142 bprm->p++;
1143 bprm->argc--;
1144 ret = 0;
Nick Piggin4fc75ff2007-05-08 00:25:16 -07001145
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001146out:
1147 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149EXPORT_SYMBOL(remove_arg_zero);
1150
1151/*
1152 * cycle the list of binary formats handler, until one recognizes the image
1153 */
1154int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
1155{
1156 int try,retval;
1157 struct linux_binfmt *fmt;
David Howells7fa30312008-02-08 04:19:28 -08001158#if defined(__alpha__) && defined(CONFIG_ARCH_SUPPORTS_AOUT)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 /* handle /sbin/loader.. */
1160 {
1161 struct exec * eh = (struct exec *) bprm->buf;
1162
1163 if (!bprm->loader && eh->fh.f_magic == 0x183 &&
1164 (eh->fh.f_flags & 0x3000) == 0x3000)
1165 {
1166 struct file * file;
1167 unsigned long loader;
1168
1169 allow_write_access(bprm->file);
1170 fput(bprm->file);
1171 bprm->file = NULL;
1172
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001173 loader = bprm->vma->vm_end - sizeof(void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174
1175 file = open_exec("/sbin/loader");
1176 retval = PTR_ERR(file);
1177 if (IS_ERR(file))
1178 return retval;
1179
1180 /* Remember if the application is TASO. */
1181 bprm->sh_bang = eh->ah.entry < 0x100000000UL;
1182
1183 bprm->file = file;
1184 bprm->loader = loader;
1185 retval = prepare_binprm(bprm);
1186 if (retval<0)
1187 return retval;
1188 /* should call search_binary_handler recursively here,
1189 but it does not matter */
1190 }
1191 }
1192#endif
1193 retval = security_bprm_check(bprm);
1194 if (retval)
1195 return retval;
1196
1197 /* kernel module loader fixup */
1198 /* so we don't try to load run modprobe in kernel space. */
1199 set_fs(USER_DS);
Al Viro473ae302006-04-26 14:04:08 -04001200
1201 retval = audit_bprm(bprm);
1202 if (retval)
1203 return retval;
1204
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 retval = -ENOENT;
1206 for (try=0; try<2; try++) {
1207 read_lock(&binfmt_lock);
Alexey Dobriyane4dc1b12007-10-16 23:26:03 -07001208 list_for_each_entry(fmt, &formats, lh) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
1210 if (!fn)
1211 continue;
1212 if (!try_module_get(fmt->module))
1213 continue;
1214 read_unlock(&binfmt_lock);
1215 retval = fn(bprm, regs);
1216 if (retval >= 0) {
1217 put_binfmt(fmt);
1218 allow_write_access(bprm->file);
1219 if (bprm->file)
1220 fput(bprm->file);
1221 bprm->file = NULL;
1222 current->did_exec = 1;
Matt Helsley9f460802005-11-07 00:59:16 -08001223 proc_exec_connector(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 return retval;
1225 }
1226 read_lock(&binfmt_lock);
1227 put_binfmt(fmt);
1228 if (retval != -ENOEXEC || bprm->mm == NULL)
1229 break;
1230 if (!bprm->file) {
1231 read_unlock(&binfmt_lock);
1232 return retval;
1233 }
1234 }
1235 read_unlock(&binfmt_lock);
1236 if (retval != -ENOEXEC || bprm->mm == NULL) {
1237 break;
1238#ifdef CONFIG_KMOD
1239 }else{
1240#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1241 if (printable(bprm->buf[0]) &&
1242 printable(bprm->buf[1]) &&
1243 printable(bprm->buf[2]) &&
1244 printable(bprm->buf[3]))
1245 break; /* -ENOEXEC */
1246 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
1247#endif
1248 }
1249 }
1250 return retval;
1251}
1252
1253EXPORT_SYMBOL(search_binary_handler);
1254
Al Viro08a6fac2008-05-10 16:38:25 -04001255void free_bprm(struct linux_binprm *bprm)
1256{
1257 free_arg_pages(bprm);
1258 kfree(bprm);
1259}
1260
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261/*
1262 * sys_execve() executes a new program.
1263 */
1264int do_execve(char * filename,
1265 char __user *__user *argv,
1266 char __user *__user *envp,
1267 struct pt_regs * regs)
1268{
1269 struct linux_binprm *bprm;
1270 struct file *file;
Al Viro3b125382008-04-22 05:31:30 -04001271 struct files_struct *displaced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
Al Viro3b125382008-04-22 05:31:30 -04001274 retval = unshare_files(&displaced);
Al Virofd8328b2008-04-22 05:11:59 -04001275 if (retval)
1276 goto out_ret;
1277
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 retval = -ENOMEM;
Oliver Neukum11b0b5a2006-03-25 03:08:13 -08001279 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 if (!bprm)
Al Virofd8328b2008-04-22 05:11:59 -04001281 goto out_files;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282
1283 file = open_exec(filename);
1284 retval = PTR_ERR(file);
1285 if (IS_ERR(file))
1286 goto out_kfree;
1287
1288 sched_exec();
1289
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 bprm->file = file;
1291 bprm->filename = filename;
1292 bprm->interp = filename;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001293
1294 retval = bprm_mm_init(bprm);
1295 if (retval)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 goto out_file;
1297
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001298 bprm->argc = count(argv, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 if ((retval = bprm->argc) < 0)
1300 goto out_mm;
1301
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001302 bprm->envc = count(envp, MAX_ARG_STRINGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 if ((retval = bprm->envc) < 0)
1304 goto out_mm;
1305
1306 retval = security_bprm_alloc(bprm);
1307 if (retval)
1308 goto out;
1309
1310 retval = prepare_binprm(bprm);
1311 if (retval < 0)
1312 goto out;
1313
1314 retval = copy_strings_kernel(1, &bprm->filename, bprm);
1315 if (retval < 0)
1316 goto out;
1317
1318 bprm->exec = bprm->p;
1319 retval = copy_strings(bprm->envc, envp, bprm);
1320 if (retval < 0)
1321 goto out;
1322
1323 retval = copy_strings(bprm->argc, argv, bprm);
1324 if (retval < 0)
1325 goto out;
1326
1327 retval = search_binary_handler(bprm,regs);
1328 if (retval >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 /* execve success */
1330 security_bprm_free(bprm);
1331 acct_update_integrals(current);
Al Viro08a6fac2008-05-10 16:38:25 -04001332 free_bprm(bprm);
Al Viro3b125382008-04-22 05:31:30 -04001333 if (displaced)
1334 put_files_struct(displaced);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 return retval;
1336 }
1337
1338out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 if (bprm->security)
1340 security_bprm_free(bprm);
1341
1342out_mm:
1343 if (bprm->mm)
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001344 mmput (bprm->mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
1346out_file:
1347 if (bprm->file) {
1348 allow_write_access(bprm->file);
1349 fput(bprm->file);
1350 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351out_kfree:
Al Viro08a6fac2008-05-10 16:38:25 -04001352 free_bprm(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353
Al Virofd8328b2008-04-22 05:11:59 -04001354out_files:
Al Viro3b125382008-04-22 05:31:30 -04001355 if (displaced)
1356 reset_files_struct(displaced);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357out_ret:
1358 return retval;
1359}
1360
1361int set_binfmt(struct linux_binfmt *new)
1362{
1363 struct linux_binfmt *old = current->binfmt;
1364
1365 if (new) {
1366 if (!try_module_get(new->module))
1367 return -1;
1368 }
1369 current->binfmt = new;
1370 if (old)
1371 module_put(old->module);
1372 return 0;
1373}
1374
1375EXPORT_SYMBOL(set_binfmt);
1376
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377/* format_corename will inspect the pattern parameter, and output a
1378 * name into corename, which must have space for at least
1379 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
1380 */
Alan Coxc4bbafd2007-04-16 22:53:13 -07001381static int format_corename(char *corename, const char *pattern, long signr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382{
1383 const char *pat_ptr = pattern;
1384 char *out_ptr = corename;
1385 char *const out_end = corename + CORENAME_MAX_SIZE;
1386 int rc;
1387 int pid_in_pattern = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001388 int ispipe = 0;
1389
1390 if (*pattern == '|')
1391 ispipe = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392
1393 /* Repeat as long as we have more pattern to process and more output
1394 space */
1395 while (*pat_ptr) {
1396 if (*pat_ptr != '%') {
1397 if (out_ptr == out_end)
1398 goto out;
1399 *out_ptr++ = *pat_ptr++;
1400 } else {
1401 switch (*++pat_ptr) {
1402 case 0:
1403 goto out;
1404 /* Double percent, output one percent */
1405 case '%':
1406 if (out_ptr == out_end)
1407 goto out;
1408 *out_ptr++ = '%';
1409 break;
1410 /* pid */
1411 case 'p':
1412 pid_in_pattern = 1;
1413 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001414 "%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 if (rc > out_end - out_ptr)
1416 goto out;
1417 out_ptr += rc;
1418 break;
1419 /* uid */
1420 case 'u':
1421 rc = snprintf(out_ptr, out_end - out_ptr,
1422 "%d", current->uid);
1423 if (rc > out_end - out_ptr)
1424 goto out;
1425 out_ptr += rc;
1426 break;
1427 /* gid */
1428 case 'g':
1429 rc = snprintf(out_ptr, out_end - out_ptr,
1430 "%d", current->gid);
1431 if (rc > out_end - out_ptr)
1432 goto out;
1433 out_ptr += rc;
1434 break;
1435 /* signal that caused the coredump */
1436 case 's':
1437 rc = snprintf(out_ptr, out_end - out_ptr,
1438 "%ld", signr);
1439 if (rc > out_end - out_ptr)
1440 goto out;
1441 out_ptr += rc;
1442 break;
1443 /* UNIX time of coredump */
1444 case 't': {
1445 struct timeval tv;
1446 do_gettimeofday(&tv);
1447 rc = snprintf(out_ptr, out_end - out_ptr,
1448 "%lu", tv.tv_sec);
1449 if (rc > out_end - out_ptr)
1450 goto out;
1451 out_ptr += rc;
1452 break;
1453 }
1454 /* hostname */
1455 case 'h':
1456 down_read(&uts_sem);
1457 rc = snprintf(out_ptr, out_end - out_ptr,
Serge E. Hallyne9ff3992006-10-02 02:18:11 -07001458 "%s", utsname()->nodename);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 up_read(&uts_sem);
1460 if (rc > out_end - out_ptr)
1461 goto out;
1462 out_ptr += rc;
1463 break;
1464 /* executable */
1465 case 'e':
1466 rc = snprintf(out_ptr, out_end - out_ptr,
1467 "%s", current->comm);
1468 if (rc > out_end - out_ptr)
1469 goto out;
1470 out_ptr += rc;
1471 break;
Neil Horman74aadce2007-10-16 23:26:35 -07001472 /* core limit size */
1473 case 'c':
1474 rc = snprintf(out_ptr, out_end - out_ptr,
1475 "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
1476 if (rc > out_end - out_ptr)
1477 goto out;
1478 out_ptr += rc;
1479 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 default:
1481 break;
1482 }
1483 ++pat_ptr;
1484 }
1485 }
1486 /* Backward compatibility with core_uses_pid:
1487 *
1488 * If core_pattern does not include a %p (as is the default)
1489 * and core_uses_pid is set, then .%pid will be appended to
Alan Coxc4bbafd2007-04-16 22:53:13 -07001490 * the filename. Do not do this for piped commands. */
1491 if (!ispipe && !pid_in_pattern
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 && (core_uses_pid || atomic_read(&current->mm->mm_users) != 1)) {
1493 rc = snprintf(out_ptr, out_end - out_ptr,
Pavel Emelyanovb4888932007-10-18 23:40:14 -07001494 ".%d", task_tgid_vnr(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 if (rc > out_end - out_ptr)
1496 goto out;
1497 out_ptr += rc;
1498 }
Alan Coxc4bbafd2007-04-16 22:53:13 -07001499out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 *out_ptr = 0;
Alan Coxc4bbafd2007-04-16 22:53:13 -07001501 return ispipe;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502}
1503
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001504static void zap_process(struct task_struct *start)
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001505{
1506 struct task_struct *t;
Oleg Nesterov281de332006-06-26 00:26:06 -07001507
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001508 start->signal->flags = SIGNAL_GROUP_EXIT;
1509 start->signal->group_stop_count = 0;
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001510
1511 t = start;
1512 do {
1513 if (t != current && t->mm) {
1514 t->mm->core_waiters++;
Oleg Nesterov281de332006-06-26 00:26:06 -07001515 sigaddset(&t->pending.signal, SIGKILL);
1516 signal_wake_up(t, 1);
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001517 }
1518 } while ((t = next_thread(t)) != start);
1519}
1520
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001521static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
1522 int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523{
1524 struct task_struct *g, *p;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001525 unsigned long flags;
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001526 int err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001528 spin_lock_irq(&tsk->sighand->siglock);
Oleg Nesteroved5d2ca2008-02-04 22:27:24 -08001529 if (!signal_group_exit(tsk->signal)) {
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001530 tsk->signal->group_exit_code = exit_code;
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001531 zap_process(tsk);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001532 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 }
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001534 spin_unlock_irq(&tsk->sighand->siglock);
1535 if (err)
1536 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001538 if (atomic_read(&mm->mm_users) == mm->core_waiters + 1)
1539 goto done;
1540
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001541 rcu_read_lock();
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001542 for_each_process(g) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001543 if (g == tsk->group_leader)
1544 continue;
1545
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001546 p = g;
1547 do {
1548 if (p->mm) {
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001549 if (p->mm == mm) {
1550 /*
1551 * p->sighand can't disappear, but
1552 * may be changed by de_thread()
1553 */
1554 lock_task_sighand(p, &flags);
Oleg Nesterovd5f70c02006-06-26 00:26:07 -07001555 zap_process(p);
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001556 unlock_task_sighand(p, &flags);
1557 }
Oleg Nesterovaceecc042006-06-26 00:26:05 -07001558 break;
1559 }
1560 } while ((p = next_thread(p)) != g);
1561 }
Oleg Nesterov7b1c6152006-06-26 00:26:08 -07001562 rcu_read_unlock();
Oleg Nesterov5debfa62006-06-26 00:26:09 -07001563done:
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001564 return mm->core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565}
1566
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001567static int coredump_wait(int exit_code)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568{
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001569 struct task_struct *tsk = current;
1570 struct mm_struct *mm = tsk->mm;
1571 struct completion startup_done;
1572 struct completion *vfork_done;
Oleg Nesterov2384f552005-10-30 15:02:47 -08001573 int core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001575 init_completion(&mm->core_done);
1576 init_completion(&startup_done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577 mm->core_startup_done = &startup_done;
1578
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001579 core_waiters = zap_threads(tsk, mm, exit_code);
Oleg Nesterov2384f552005-10-30 15:02:47 -08001580 up_write(&mm->mmap_sem);
1581
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001582 if (unlikely(core_waiters < 0))
1583 goto fail;
1584
1585 /*
1586 * Make sure nobody is waiting for us to release the VM,
1587 * otherwise we can deadlock when we wait on each other
1588 */
1589 vfork_done = tsk->vfork_done;
1590 if (vfork_done) {
1591 tsk->vfork_done = NULL;
1592 complete(vfork_done);
1593 }
1594
Oleg Nesterov2384f552005-10-30 15:02:47 -08001595 if (core_waiters)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596 wait_for_completion(&startup_done);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001597fail:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001598 BUG_ON(mm->core_waiters);
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001599 return core_waiters;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600}
1601
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001602/*
1603 * set_dumpable converts traditional three-value dumpable to two flags and
1604 * stores them into mm->flags. It modifies lower two bits of mm->flags, but
1605 * these bits are not changed atomically. So get_dumpable can observe the
1606 * intermediate state. To avoid doing unexpected behavior, get get_dumpable
1607 * return either old dumpable or new one by paying attention to the order of
1608 * modifying the bits.
1609 *
1610 * dumpable | mm->flags (binary)
1611 * old new | initial interim final
1612 * ---------+-----------------------
1613 * 0 1 | 00 01 01
1614 * 0 2 | 00 10(*) 11
1615 * 1 0 | 01 00 00
1616 * 1 2 | 01 11 11
1617 * 2 0 | 11 10(*) 00
1618 * 2 1 | 11 11 01
1619 *
1620 * (*) get_dumpable regards interim value of 10 as 11.
1621 */
1622void set_dumpable(struct mm_struct *mm, int value)
1623{
1624 switch (value) {
1625 case 0:
1626 clear_bit(MMF_DUMPABLE, &mm->flags);
1627 smp_wmb();
1628 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1629 break;
1630 case 1:
1631 set_bit(MMF_DUMPABLE, &mm->flags);
1632 smp_wmb();
1633 clear_bit(MMF_DUMP_SECURELY, &mm->flags);
1634 break;
1635 case 2:
1636 set_bit(MMF_DUMP_SECURELY, &mm->flags);
1637 smp_wmb();
1638 set_bit(MMF_DUMPABLE, &mm->flags);
1639 break;
1640 }
1641}
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001642
1643int get_dumpable(struct mm_struct *mm)
1644{
1645 int ret;
1646
1647 ret = mm->flags & 0x3;
1648 return (ret >= 2) ? 2 : ret;
1649}
1650
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651int do_coredump(long signr, int exit_code, struct pt_regs * regs)
1652{
1653 char corename[CORENAME_MAX_SIZE + 1];
1654 struct mm_struct *mm = current->mm;
1655 struct linux_binfmt * binfmt;
1656 struct inode * inode;
1657 struct file * file;
1658 int retval = 0;
Alan Coxd6e71142005-06-23 00:09:43 -07001659 int fsuid = current->fsuid;
1660 int flag = 0;
Andi Kleend025c9d2006-09-30 23:29:28 -07001661 int ispipe = 0;
Neil Horman7dc0b222007-10-16 23:26:34 -07001662 unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
Neil Horman74aadce2007-10-16 23:26:35 -07001663 char **helper_argv = NULL;
1664 int helper_argc = 0;
1665 char *delimit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666
Steve Grubb0a4ff8c2007-04-19 10:28:21 -04001667 audit_core_dumps(signr);
1668
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 binfmt = current->binfmt;
1670 if (!binfmt || !binfmt->core_dump)
1671 goto fail;
1672 down_write(&mm->mmap_sem);
Roland McGrath00ec99d2007-11-11 19:13:43 -08001673 /*
1674 * If another thread got here first, or we are not dumpable, bail out.
1675 */
1676 if (mm->core_waiters || !get_dumpable(mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 up_write(&mm->mmap_sem);
1678 goto fail;
1679 }
Alan Coxd6e71142005-06-23 00:09:43 -07001680
1681 /*
1682 * We cannot trust fsuid as being the "true" uid of the
1683 * process nor do we know its entire history. We only know it
1684 * was tainted so we dump it as root in mode 2.
1685 */
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -07001686 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
Alan Coxd6e71142005-06-23 00:09:43 -07001687 flag = O_EXCL; /* Stop rewrite attacks */
1688 current->fsuid = 0; /* Dump root private */
1689 }
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001690
Oleg Nesterovdcf560c2006-06-26 00:26:08 -07001691 retval = coredump_wait(exit_code);
1692 if (retval < 0)
Oleg Nesterov1291cf42005-10-30 15:02:54 -08001693 goto fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694
1695 /*
1696 * Clear any false indication of pending signals that might
1697 * be seen by the filesystem code called to write the core file.
1698 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699 clear_thread_flag(TIF_SIGPENDING);
1700
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 /*
1702 * lock_kernel() because format_corename() is controlled by sysctl, which
1703 * uses lock_kernel()
1704 */
1705 lock_kernel();
Alan Coxc4bbafd2007-04-16 22:53:13 -07001706 ispipe = format_corename(corename, core_pattern, signr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 unlock_kernel();
Neil Horman7dc0b222007-10-16 23:26:34 -07001708 /*
1709 * Don't bother to check the RLIMIT_CORE value if core_pattern points
1710 * to a pipe. Since we're not writing directly to the filesystem
1711 * RLIMIT_CORE doesn't really apply, as no actual core file will be
1712 * created unless the pipe reader choses to write out the core file
1713 * at which point file size limits and permissions will be imposed
1714 * as it does with any other process
1715 */
Neil Horman74aadce2007-10-16 23:26:35 -07001716 if ((!ispipe) && (core_limit < binfmt->min_coredump))
Neil Horman7dc0b222007-10-16 23:26:34 -07001717 goto fail_unlock;
1718
Alan Coxc4bbafd2007-04-16 22:53:13 -07001719 if (ispipe) {
Neil Horman74aadce2007-10-16 23:26:35 -07001720 helper_argv = argv_split(GFP_KERNEL, corename+1, &helper_argc);
1721 /* Terminate the string before the first option */
1722 delimit = strchr(corename, ' ');
1723 if (delimit)
1724 *delimit = '\0';
Neil Horman32321132007-10-16 23:26:36 -07001725 delimit = strrchr(helper_argv[0], '/');
1726 if (delimit)
1727 delimit++;
1728 else
1729 delimit = helper_argv[0];
1730 if (!strcmp(delimit, current->comm)) {
1731 printk(KERN_NOTICE "Recursive core dump detected, "
1732 "aborting\n");
1733 goto fail_unlock;
1734 }
1735
1736 core_limit = RLIM_INFINITY;
1737
Andi Kleend025c9d2006-09-30 23:29:28 -07001738 /* SIGPIPE can happen, but it's just never processed */
Neil Horman32321132007-10-16 23:26:36 -07001739 if (call_usermodehelper_pipe(corename+1, helper_argv, NULL,
1740 &file)) {
Andi Kleend025c9d2006-09-30 23:29:28 -07001741 printk(KERN_INFO "Core dump to %s pipe failed\n",
1742 corename);
1743 goto fail_unlock;
1744 }
Andi Kleend025c9d2006-09-30 23:29:28 -07001745 } else
1746 file = filp_open(corename,
Alexey Dobriyan6d4df672006-12-06 20:40:39 -08001747 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
1748 0600);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 if (IS_ERR(file))
1750 goto fail_unlock;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001751 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752 if (inode->i_nlink > 1)
1753 goto close_fail; /* multiple links - don't dump */
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001754 if (!ispipe && d_unhashed(file->f_path.dentry))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755 goto close_fail;
1756
Andi Kleend025c9d2006-09-30 23:29:28 -07001757 /* AK: actually i see no reason to not allow this for named pipes etc.,
1758 but keep the previous behaviour for now. */
1759 if (!ispipe && !S_ISREG(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 goto close_fail;
Ingo Molnarc46f7392007-11-28 13:59:18 +01001761 /*
1762 * Dont allow local users get cute and trick others to coredump
1763 * into their pre-created files:
1764 */
1765 if (inode->i_uid != current->fsuid)
1766 goto close_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767 if (!file->f_op)
1768 goto close_fail;
1769 if (!file->f_op->write)
1770 goto close_fail;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001771 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 goto close_fail;
1773
Neil Horman7dc0b222007-10-16 23:26:34 -07001774 retval = binfmt->core_dump(signr, regs, file, core_limit);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
1776 if (retval)
1777 current->signal->group_exit_code |= 0x80;
1778close_fail:
1779 filp_close(file, NULL);
1780fail_unlock:
Neil Horman74aadce2007-10-16 23:26:35 -07001781 if (helper_argv)
1782 argv_free(helper_argv);
1783
Alan Coxd6e71142005-06-23 00:09:43 -07001784 current->fsuid = fsuid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 complete_all(&mm->core_done);
1786fail:
1787 return retval;
1788}