Root/
Source at commit 6c17a31f1fc515425221067cb3ece599c09dbc5d created 12 years 8 months ago. By Werner Almesberger, atusb, atben: moved from spi/ to ieee802154/; renamed atusb to spi_atusb | |
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1 | /* |
2 | * linux/fs/exec.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | */ |
6 | |
7 | /* |
8 | * #!-checking implemented by tytso. |
9 | */ |
10 | /* |
11 | * Demand-loading implemented 01.12.91 - no need to read anything but |
12 | * the header into memory. The inode of the executable is put into |
13 | * "current->executable", and page faults do the actual loading. Clean. |
14 | * |
15 | * Once more I can proudly say that linux stood up to being changed: it |
16 | * was less than 2 hours work to get demand-loading completely implemented. |
17 | * |
18 | * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, |
19 | * current->executable is only used by the procfs. This allows a dispatch |
20 | * table to check for several different types of binary formats. We keep |
21 | * trying until we recognize the file or we run out of supported binary |
22 | * formats. |
23 | */ |
24 | |
25 | #include <linux/slab.h> |
26 | #include <linux/file.h> |
27 | #include <linux/fdtable.h> |
28 | #include <linux/mm.h> |
29 | #include <linux/stat.h> |
30 | #include <linux/fcntl.h> |
31 | #include <linux/swap.h> |
32 | #include <linux/string.h> |
33 | #include <linux/init.h> |
34 | #include <linux/pagemap.h> |
35 | #include <linux/perf_event.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/utsname.h> |
42 | #include <linux/pid_namespace.h> |
43 | #include <linux/module.h> |
44 | #include <linux/namei.h> |
45 | #include <linux/proc_fs.h> |
46 | #include <linux/mount.h> |
47 | #include <linux/security.h> |
48 | #include <linux/syscalls.h> |
49 | #include <linux/tsacct_kern.h> |
50 | #include <linux/cn_proc.h> |
51 | #include <linux/audit.h> |
52 | #include <linux/tracehook.h> |
53 | #include <linux/kmod.h> |
54 | #include <linux/fsnotify.h> |
55 | #include <linux/fs_struct.h> |
56 | #include <linux/pipe_fs_i.h> |
57 | #include <linux/oom.h> |
58 | |
59 | #include <asm/uaccess.h> |
60 | #include <asm/mmu_context.h> |
61 | #include <asm/tlb.h> |
62 | #include "internal.h" |
63 | |
64 | int core_uses_pid; |
65 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
66 | unsigned int core_pipe_limit; |
67 | int suid_dumpable = 0; |
68 | |
69 | struct core_name { |
70 | char *corename; |
71 | int used, size; |
72 | }; |
73 | static atomic_t call_count = ATOMIC_INIT(1); |
74 | |
75 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
76 | |
77 | static LIST_HEAD(formats); |
78 | static DEFINE_RWLOCK(binfmt_lock); |
79 | |
80 | int __register_binfmt(struct linux_binfmt * fmt, int insert) |
81 | { |
82 | if (!fmt) |
83 | return -EINVAL; |
84 | write_lock(&binfmt_lock); |
85 | insert ? list_add(&fmt->lh, &formats) : |
86 | list_add_tail(&fmt->lh, &formats); |
87 | write_unlock(&binfmt_lock); |
88 | return 0; |
89 | } |
90 | |
91 | EXPORT_SYMBOL(__register_binfmt); |
92 | |
93 | void unregister_binfmt(struct linux_binfmt * fmt) |
94 | { |
95 | write_lock(&binfmt_lock); |
96 | list_del(&fmt->lh); |
97 | write_unlock(&binfmt_lock); |
98 | } |
99 | |
100 | EXPORT_SYMBOL(unregister_binfmt); |
101 | |
102 | static inline void put_binfmt(struct linux_binfmt * fmt) |
103 | { |
104 | module_put(fmt->module); |
105 | } |
106 | |
107 | /* |
108 | * Note that a shared library must be both readable and executable due to |
109 | * security reasons. |
110 | * |
111 | * Also note that we take the address to load from from the file itself. |
112 | */ |
113 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
114 | { |
115 | struct file *file; |
116 | char *tmp = getname(library); |
117 | int error = PTR_ERR(tmp); |
118 | |
119 | if (IS_ERR(tmp)) |
120 | goto out; |
121 | |
122 | file = do_filp_open(AT_FDCWD, tmp, |
123 | O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 0, |
124 | MAY_READ | MAY_EXEC | MAY_OPEN); |
125 | putname(tmp); |
126 | error = PTR_ERR(file); |
127 | if (IS_ERR(file)) |
128 | goto out; |
129 | |
130 | error = -EINVAL; |
131 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
132 | goto exit; |
133 | |
134 | error = -EACCES; |
135 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
136 | goto exit; |
137 | |
138 | fsnotify_open(file); |
139 | |
140 | error = -ENOEXEC; |
141 | if(file->f_op) { |
142 | struct linux_binfmt * fmt; |
143 | |
144 | read_lock(&binfmt_lock); |
145 | list_for_each_entry(fmt, &formats, lh) { |
146 | if (!fmt->load_shlib) |
147 | continue; |
148 | if (!try_module_get(fmt->module)) |
149 | continue; |
150 | read_unlock(&binfmt_lock); |
151 | error = fmt->load_shlib(file); |
152 | read_lock(&binfmt_lock); |
153 | put_binfmt(fmt); |
154 | if (error != -ENOEXEC) |
155 | break; |
156 | } |
157 | read_unlock(&binfmt_lock); |
158 | } |
159 | exit: |
160 | fput(file); |
161 | out: |
162 | return error; |
163 | } |
164 | |
165 | #ifdef CONFIG_MMU |
166 | |
167 | void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
168 | { |
169 | struct mm_struct *mm = current->mm; |
170 | long diff = (long)(pages - bprm->vma_pages); |
171 | |
172 | if (!mm || !diff) |
173 | return; |
174 | |
175 | bprm->vma_pages = pages; |
176 | |
177 | #ifdef SPLIT_RSS_COUNTING |
178 | add_mm_counter(mm, MM_ANONPAGES, diff); |
179 | #else |
180 | spin_lock(&mm->page_table_lock); |
181 | add_mm_counter(mm, MM_ANONPAGES, diff); |
182 | spin_unlock(&mm->page_table_lock); |
183 | #endif |
184 | } |
185 | |
186 | struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
187 | int write) |
188 | { |
189 | struct page *page; |
190 | int ret; |
191 | |
192 | #ifdef CONFIG_STACK_GROWSUP |
193 | if (write) { |
194 | ret = expand_stack_downwards(bprm->vma, pos); |
195 | if (ret < 0) |
196 | return NULL; |
197 | } |
198 | #endif |
199 | ret = get_user_pages(current, bprm->mm, pos, |
200 | 1, write, 1, &page, NULL); |
201 | if (ret <= 0) |
202 | return NULL; |
203 | |
204 | if (write) { |
205 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
206 | struct rlimit *rlim; |
207 | |
208 | acct_arg_size(bprm, size / PAGE_SIZE); |
209 | |
210 | /* |
211 | * We've historically supported up to 32 pages (ARG_MAX) |
212 | * of argument strings even with small stacks |
213 | */ |
214 | if (size <= ARG_MAX) |
215 | return page; |
216 | |
217 | /* |
218 | * Limit to 1/4-th the stack size for the argv+env strings. |
219 | * This ensures that: |
220 | * - the remaining binfmt code will not run out of stack space, |
221 | * - the program will have a reasonable amount of stack left |
222 | * to work from. |
223 | */ |
224 | rlim = current->signal->rlim; |
225 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
226 | put_page(page); |
227 | return NULL; |
228 | } |
229 | } |
230 | |
231 | return page; |
232 | } |
233 | |
234 | static void put_arg_page(struct page *page) |
235 | { |
236 | put_page(page); |
237 | } |
238 | |
239 | static void free_arg_page(struct linux_binprm *bprm, int i) |
240 | { |
241 | } |
242 | |
243 | static void free_arg_pages(struct linux_binprm *bprm) |
244 | { |
245 | } |
246 | |
247 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
248 | struct page *page) |
249 | { |
250 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); |
251 | } |
252 | |
253 | static int __bprm_mm_init(struct linux_binprm *bprm) |
254 | { |
255 | int err; |
256 | struct vm_area_struct *vma = NULL; |
257 | struct mm_struct *mm = bprm->mm; |
258 | |
259 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
260 | if (!vma) |
261 | return -ENOMEM; |
262 | |
263 | down_write(&mm->mmap_sem); |
264 | vma->vm_mm = mm; |
265 | |
266 | /* |
267 | * Place the stack at the largest stack address the architecture |
268 | * supports. Later, we'll move this to an appropriate place. We don't |
269 | * use STACK_TOP because that can depend on attributes which aren't |
270 | * configured yet. |
271 | */ |
272 | BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
273 | vma->vm_end = STACK_TOP_MAX; |
274 | vma->vm_start = vma->vm_end - PAGE_SIZE; |
275 | vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
276 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
277 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
278 | |
279 | err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1); |
280 | if (err) |
281 | goto err; |
282 | |
283 | err = insert_vm_struct(mm, vma); |
284 | if (err) |
285 | goto err; |
286 | |
287 | mm->stack_vm = mm->total_vm = 1; |
288 | up_write(&mm->mmap_sem); |
289 | bprm->p = vma->vm_end - sizeof(void *); |
290 | return 0; |
291 | err: |
292 | up_write(&mm->mmap_sem); |
293 | bprm->vma = NULL; |
294 | kmem_cache_free(vm_area_cachep, vma); |
295 | return err; |
296 | } |
297 | |
298 | static bool valid_arg_len(struct linux_binprm *bprm, long len) |
299 | { |
300 | return len <= MAX_ARG_STRLEN; |
301 | } |
302 | |
303 | #else |
304 | |
305 | void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
306 | { |
307 | } |
308 | |
309 | struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
310 | int write) |
311 | { |
312 | struct page *page; |
313 | |
314 | page = bprm->page[pos / PAGE_SIZE]; |
315 | if (!page && write) { |
316 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); |
317 | if (!page) |
318 | return NULL; |
319 | bprm->page[pos / PAGE_SIZE] = page; |
320 | } |
321 | |
322 | return page; |
323 | } |
324 | |
325 | static void put_arg_page(struct page *page) |
326 | { |
327 | } |
328 | |
329 | static void free_arg_page(struct linux_binprm *bprm, int i) |
330 | { |
331 | if (bprm->page[i]) { |
332 | __free_page(bprm->page[i]); |
333 | bprm->page[i] = NULL; |
334 | } |
335 | } |
336 | |
337 | static void free_arg_pages(struct linux_binprm *bprm) |
338 | { |
339 | int i; |
340 | |
341 | for (i = 0; i < MAX_ARG_PAGES; i++) |
342 | free_arg_page(bprm, i); |
343 | } |
344 | |
345 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
346 | struct page *page) |
347 | { |
348 | } |
349 | |
350 | static int __bprm_mm_init(struct linux_binprm *bprm) |
351 | { |
352 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); |
353 | return 0; |
354 | } |
355 | |
356 | static bool valid_arg_len(struct linux_binprm *bprm, long len) |
357 | { |
358 | return len <= bprm->p; |
359 | } |
360 | |
361 | #endif /* CONFIG_MMU */ |
362 | |
363 | /* |
364 | * Create a new mm_struct and populate it with a temporary stack |
365 | * vm_area_struct. We don't have enough context at this point to set the stack |
366 | * flags, permissions, and offset, so we use temporary values. We'll update |
367 | * them later in setup_arg_pages(). |
368 | */ |
369 | int bprm_mm_init(struct linux_binprm *bprm) |
370 | { |
371 | int err; |
372 | struct mm_struct *mm = NULL; |
373 | |
374 | bprm->mm = mm = mm_alloc(); |
375 | err = -ENOMEM; |
376 | if (!mm) |
377 | goto err; |
378 | |
379 | err = init_new_context(current, mm); |
380 | if (err) |
381 | goto err; |
382 | |
383 | err = __bprm_mm_init(bprm); |
384 | if (err) |
385 | goto err; |
386 | |
387 | return 0; |
388 | |
389 | err: |
390 | if (mm) { |
391 | bprm->mm = NULL; |
392 | mmdrop(mm); |
393 | } |
394 | |
395 | return err; |
396 | } |
397 | |
398 | /* |
399 | * count() counts the number of strings in array ARGV. |
400 | */ |
401 | static int count(const char __user * const __user * argv, int max) |
402 | { |
403 | int i = 0; |
404 | |
405 | if (argv != NULL) { |
406 | for (;;) { |
407 | const char __user * p; |
408 | |
409 | if (get_user(p, argv)) |
410 | return -EFAULT; |
411 | if (!p) |
412 | break; |
413 | argv++; |
414 | if (i++ >= max) |
415 | return -E2BIG; |
416 | |
417 | if (fatal_signal_pending(current)) |
418 | return -ERESTARTNOHAND; |
419 | cond_resched(); |
420 | } |
421 | } |
422 | return i; |
423 | } |
424 | |
425 | /* |
426 | * 'copy_strings()' copies argument/environment strings from the old |
427 | * processes's memory to the new process's stack. The call to get_user_pages() |
428 | * ensures the destination page is created and not swapped out. |
429 | */ |
430 | static int copy_strings(int argc, const char __user *const __user *argv, |
431 | struct linux_binprm *bprm) |
432 | { |
433 | struct page *kmapped_page = NULL; |
434 | char *kaddr = NULL; |
435 | unsigned long kpos = 0; |
436 | int ret; |
437 | |
438 | while (argc-- > 0) { |
439 | const char __user *str; |
440 | int len; |
441 | unsigned long pos; |
442 | |
443 | if (get_user(str, argv+argc) || |
444 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
445 | ret = -EFAULT; |
446 | goto out; |
447 | } |
448 | |
449 | if (!valid_arg_len(bprm, len)) { |
450 | ret = -E2BIG; |
451 | goto out; |
452 | } |
453 | |
454 | /* We're going to work our way backwords. */ |
455 | pos = bprm->p; |
456 | str += len; |
457 | bprm->p -= len; |
458 | |
459 | while (len > 0) { |
460 | int offset, bytes_to_copy; |
461 | |
462 | if (fatal_signal_pending(current)) { |
463 | ret = -ERESTARTNOHAND; |
464 | goto out; |
465 | } |
466 | cond_resched(); |
467 | |
468 | offset = pos % PAGE_SIZE; |
469 | if (offset == 0) |
470 | offset = PAGE_SIZE; |
471 | |
472 | bytes_to_copy = offset; |
473 | if (bytes_to_copy > len) |
474 | bytes_to_copy = len; |
475 | |
476 | offset -= bytes_to_copy; |
477 | pos -= bytes_to_copy; |
478 | str -= bytes_to_copy; |
479 | len -= bytes_to_copy; |
480 | |
481 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { |
482 | struct page *page; |
483 | |
484 | page = get_arg_page(bprm, pos, 1); |
485 | if (!page) { |
486 | ret = -E2BIG; |
487 | goto out; |
488 | } |
489 | |
490 | if (kmapped_page) { |
491 | flush_kernel_dcache_page(kmapped_page); |
492 | kunmap(kmapped_page); |
493 | put_arg_page(kmapped_page); |
494 | } |
495 | kmapped_page = page; |
496 | kaddr = kmap(kmapped_page); |
497 | kpos = pos & PAGE_MASK; |
498 | flush_arg_page(bprm, kpos, kmapped_page); |
499 | } |
500 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
501 | ret = -EFAULT; |
502 | goto out; |
503 | } |
504 | } |
505 | } |
506 | ret = 0; |
507 | out: |
508 | if (kmapped_page) { |
509 | flush_kernel_dcache_page(kmapped_page); |
510 | kunmap(kmapped_page); |
511 | put_arg_page(kmapped_page); |
512 | } |
513 | return ret; |
514 | } |
515 | |
516 | /* |
517 | * Like copy_strings, but get argv and its values from kernel memory. |
518 | */ |
519 | int copy_strings_kernel(int argc, const char *const *argv, |
520 | struct linux_binprm *bprm) |
521 | { |
522 | int r; |
523 | mm_segment_t oldfs = get_fs(); |
524 | set_fs(KERNEL_DS); |
525 | r = copy_strings(argc, (const char __user *const __user *)argv, bprm); |
526 | set_fs(oldfs); |
527 | return r; |
528 | } |
529 | EXPORT_SYMBOL(copy_strings_kernel); |
530 | |
531 | #ifdef CONFIG_MMU |
532 | |
533 | /* |
534 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
535 | * the binfmt code determines where the new stack should reside, we shift it to |
536 | * its final location. The process proceeds as follows: |
537 | * |
538 | * 1) Use shift to calculate the new vma endpoints. |
539 | * 2) Extend vma to cover both the old and new ranges. This ensures the |
540 | * arguments passed to subsequent functions are consistent. |
541 | * 3) Move vma's page tables to the new range. |
542 | * 4) Free up any cleared pgd range. |
543 | * 5) Shrink the vma to cover only the new range. |
544 | */ |
545 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
546 | { |
547 | struct mm_struct *mm = vma->vm_mm; |
548 | unsigned long old_start = vma->vm_start; |
549 | unsigned long old_end = vma->vm_end; |
550 | unsigned long length = old_end - old_start; |
551 | unsigned long new_start = old_start - shift; |
552 | unsigned long new_end = old_end - shift; |
553 | struct mmu_gather *tlb; |
554 | |
555 | BUG_ON(new_start > new_end); |
556 | |
557 | /* |
558 | * ensure there are no vmas between where we want to go |
559 | * and where we are |
560 | */ |
561 | if (vma != find_vma(mm, new_start)) |
562 | return -EFAULT; |
563 | |
564 | /* |
565 | * cover the whole range: [new_start, old_end) |
566 | */ |
567 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
568 | return -ENOMEM; |
569 | |
570 | /* |
571 | * move the page tables downwards, on failure we rely on |
572 | * process cleanup to remove whatever mess we made. |
573 | */ |
574 | if (length != move_page_tables(vma, old_start, |
575 | vma, new_start, length)) |
576 | return -ENOMEM; |
577 | |
578 | lru_add_drain(); |
579 | tlb = tlb_gather_mmu(mm, 0); |
580 | if (new_end > old_start) { |
581 | /* |
582 | * when the old and new regions overlap clear from new_end. |
583 | */ |
584 | free_pgd_range(tlb, new_end, old_end, new_end, |
585 | vma->vm_next ? vma->vm_next->vm_start : 0); |
586 | } else { |
587 | /* |
588 | * otherwise, clean from old_start; this is done to not touch |
589 | * the address space in [new_end, old_start) some architectures |
590 | * have constraints on va-space that make this illegal (IA64) - |
591 | * for the others its just a little faster. |
592 | */ |
593 | free_pgd_range(tlb, old_start, old_end, new_end, |
594 | vma->vm_next ? vma->vm_next->vm_start : 0); |
595 | } |
596 | tlb_finish_mmu(tlb, new_end, old_end); |
597 | |
598 | /* |
599 | * Shrink the vma to just the new range. Always succeeds. |
600 | */ |
601 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); |
602 | |
603 | return 0; |
604 | } |
605 | |
606 | /* |
607 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, |
608 | * the stack is optionally relocated, and some extra space is added. |
609 | */ |
610 | int setup_arg_pages(struct linux_binprm *bprm, |
611 | unsigned long stack_top, |
612 | int executable_stack) |
613 | { |
614 | unsigned long ret; |
615 | unsigned long stack_shift; |
616 | struct mm_struct *mm = current->mm; |
617 | struct vm_area_struct *vma = bprm->vma; |
618 | struct vm_area_struct *prev = NULL; |
619 | unsigned long vm_flags; |
620 | unsigned long stack_base; |
621 | unsigned long stack_size; |
622 | unsigned long stack_expand; |
623 | unsigned long rlim_stack; |
624 | |
625 | #ifdef CONFIG_STACK_GROWSUP |
626 | /* Limit stack size to 1GB */ |
627 | stack_base = rlimit_max(RLIMIT_STACK); |
628 | if (stack_base > (1 << 30)) |
629 | stack_base = 1 << 30; |
630 | |
631 | /* Make sure we didn't let the argument array grow too large. */ |
632 | if (vma->vm_end - vma->vm_start > stack_base) |
633 | return -ENOMEM; |
634 | |
635 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
636 | |
637 | stack_shift = vma->vm_start - stack_base; |
638 | mm->arg_start = bprm->p - stack_shift; |
639 | bprm->p = vma->vm_end - stack_shift; |
640 | #else |
641 | stack_top = arch_align_stack(stack_top); |
642 | stack_top = PAGE_ALIGN(stack_top); |
643 | |
644 | if (unlikely(stack_top < mmap_min_addr) || |
645 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) |
646 | return -ENOMEM; |
647 | |
648 | stack_shift = vma->vm_end - stack_top; |
649 | |
650 | bprm->p -= stack_shift; |
651 | mm->arg_start = bprm->p; |
652 | #endif |
653 | |
654 | if (bprm->loader) |
655 | bprm->loader -= stack_shift; |
656 | bprm->exec -= stack_shift; |
657 | |
658 | down_write(&mm->mmap_sem); |
659 | vm_flags = VM_STACK_FLAGS; |
660 | |
661 | /* |
662 | * Adjust stack execute permissions; explicitly enable for |
663 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone |
664 | * (arch default) otherwise. |
665 | */ |
666 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) |
667 | vm_flags |= VM_EXEC; |
668 | else if (executable_stack == EXSTACK_DISABLE_X) |
669 | vm_flags &= ~VM_EXEC; |
670 | vm_flags |= mm->def_flags; |
671 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
672 | |
673 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, |
674 | vm_flags); |
675 | if (ret) |
676 | goto out_unlock; |
677 | BUG_ON(prev != vma); |
678 | |
679 | /* Move stack pages down in memory. */ |
680 | if (stack_shift) { |
681 | ret = shift_arg_pages(vma, stack_shift); |
682 | if (ret) |
683 | goto out_unlock; |
684 | } |
685 | |
686 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
687 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; |
688 | |
689 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
690 | stack_size = vma->vm_end - vma->vm_start; |
691 | /* |
692 | * Align this down to a page boundary as expand_stack |
693 | * will align it up. |
694 | */ |
695 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; |
696 | #ifdef CONFIG_STACK_GROWSUP |
697 | if (stack_size + stack_expand > rlim_stack) |
698 | stack_base = vma->vm_start + rlim_stack; |
699 | else |
700 | stack_base = vma->vm_end + stack_expand; |
701 | #else |
702 | if (stack_size + stack_expand > rlim_stack) |
703 | stack_base = vma->vm_end - rlim_stack; |
704 | else |
705 | stack_base = vma->vm_start - stack_expand; |
706 | #endif |
707 | current->mm->start_stack = bprm->p; |
708 | ret = expand_stack(vma, stack_base); |
709 | if (ret) |
710 | ret = -EFAULT; |
711 | |
712 | out_unlock: |
713 | up_write(&mm->mmap_sem); |
714 | return ret; |
715 | } |
716 | EXPORT_SYMBOL(setup_arg_pages); |
717 | |
718 | #endif /* CONFIG_MMU */ |
719 | |
720 | struct file *open_exec(const char *name) |
721 | { |
722 | struct file *file; |
723 | int err; |
724 | |
725 | file = do_filp_open(AT_FDCWD, name, |
726 | O_LARGEFILE | O_RDONLY | __FMODE_EXEC, 0, |
727 | MAY_EXEC | MAY_OPEN); |
728 | if (IS_ERR(file)) |
729 | goto out; |
730 | |
731 | err = -EACCES; |
732 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
733 | goto exit; |
734 | |
735 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
736 | goto exit; |
737 | |
738 | fsnotify_open(file); |
739 | |
740 | err = deny_write_access(file); |
741 | if (err) |
742 | goto exit; |
743 | |
744 | out: |
745 | return file; |
746 | |
747 | exit: |
748 | fput(file); |
749 | return ERR_PTR(err); |
750 | } |
751 | EXPORT_SYMBOL(open_exec); |
752 | |
753 | int kernel_read(struct file *file, loff_t offset, |
754 | char *addr, unsigned long count) |
755 | { |
756 | mm_segment_t old_fs; |
757 | loff_t pos = offset; |
758 | int result; |
759 | |
760 | old_fs = get_fs(); |
761 | set_fs(get_ds()); |
762 | /* The cast to a user pointer is valid due to the set_fs() */ |
763 | result = vfs_read(file, (void __user *)addr, count, &pos); |
764 | set_fs(old_fs); |
765 | return result; |
766 | } |
767 | |
768 | EXPORT_SYMBOL(kernel_read); |
769 | |
770 | static int exec_mmap(struct mm_struct *mm) |
771 | { |
772 | struct task_struct *tsk; |
773 | struct mm_struct * old_mm, *active_mm; |
774 | |
775 | /* Notify parent that we're no longer interested in the old VM */ |
776 | tsk = current; |
777 | old_mm = current->mm; |
778 | sync_mm_rss(tsk, old_mm); |
779 | mm_release(tsk, old_mm); |
780 | |
781 | if (old_mm) { |
782 | /* |
783 | * Make sure that if there is a core dump in progress |
784 | * for the old mm, we get out and die instead of going |
785 | * through with the exec. We must hold mmap_sem around |
786 | * checking core_state and changing tsk->mm. |
787 | */ |
788 | down_read(&old_mm->mmap_sem); |
789 | if (unlikely(old_mm->core_state)) { |
790 | up_read(&old_mm->mmap_sem); |
791 | return -EINTR; |
792 | } |
793 | } |
794 | task_lock(tsk); |
795 | active_mm = tsk->active_mm; |
796 | tsk->mm = mm; |
797 | tsk->active_mm = mm; |
798 | activate_mm(active_mm, mm); |
799 | if (old_mm && tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { |
800 | atomic_dec(&old_mm->oom_disable_count); |
801 | atomic_inc(&tsk->mm->oom_disable_count); |
802 | } |
803 | task_unlock(tsk); |
804 | arch_pick_mmap_layout(mm); |
805 | if (old_mm) { |
806 | up_read(&old_mm->mmap_sem); |
807 | BUG_ON(active_mm != old_mm); |
808 | mm_update_next_owner(old_mm); |
809 | mmput(old_mm); |
810 | return 0; |
811 | } |
812 | mmdrop(active_mm); |
813 | return 0; |
814 | } |
815 | |
816 | /* |
817 | * This function makes sure the current process has its own signal table, |
818 | * so that flush_signal_handlers can later reset the handlers without |
819 | * disturbing other processes. (Other processes might share the signal |
820 | * table via the CLONE_SIGHAND option to clone().) |
821 | */ |
822 | static int de_thread(struct task_struct *tsk) |
823 | { |
824 | struct signal_struct *sig = tsk->signal; |
825 | struct sighand_struct *oldsighand = tsk->sighand; |
826 | spinlock_t *lock = &oldsighand->siglock; |
827 | |
828 | if (thread_group_empty(tsk)) |
829 | goto no_thread_group; |
830 | |
831 | /* |
832 | * Kill all other threads in the thread group. |
833 | */ |
834 | spin_lock_irq(lock); |
835 | if (signal_group_exit(sig)) { |
836 | /* |
837 | * Another group action in progress, just |
838 | * return so that the signal is processed. |
839 | */ |
840 | spin_unlock_irq(lock); |
841 | return -EAGAIN; |
842 | } |
843 | |
844 | sig->group_exit_task = tsk; |
845 | sig->notify_count = zap_other_threads(tsk); |
846 | if (!thread_group_leader(tsk)) |
847 | sig->notify_count--; |
848 | |
849 | while (sig->notify_count) { |
850 | __set_current_state(TASK_UNINTERRUPTIBLE); |
851 | spin_unlock_irq(lock); |
852 | schedule(); |
853 | spin_lock_irq(lock); |
854 | } |
855 | spin_unlock_irq(lock); |
856 | |
857 | /* |
858 | * At this point all other threads have exited, all we have to |
859 | * do is to wait for the thread group leader to become inactive, |
860 | * and to assume its PID: |
861 | */ |
862 | if (!thread_group_leader(tsk)) { |
863 | struct task_struct *leader = tsk->group_leader; |
864 | |
865 | sig->notify_count = -1; /* for exit_notify() */ |
866 | for (;;) { |
867 | write_lock_irq(&tasklist_lock); |
868 | if (likely(leader->exit_state)) |
869 | break; |
870 | __set_current_state(TASK_UNINTERRUPTIBLE); |
871 | write_unlock_irq(&tasklist_lock); |
872 | schedule(); |
873 | } |
874 | |
875 | /* |
876 | * The only record we have of the real-time age of a |
877 | * process, regardless of execs it's done, is start_time. |
878 | * All the past CPU time is accumulated in signal_struct |
879 | * from sister threads now dead. But in this non-leader |
880 | * exec, nothing survives from the original leader thread, |
881 | * whose birth marks the true age of this process now. |
882 | * When we take on its identity by switching to its PID, we |
883 | * also take its birthdate (always earlier than our own). |
884 | */ |
885 | tsk->start_time = leader->start_time; |
886 | |
887 | BUG_ON(!same_thread_group(leader, tsk)); |
888 | BUG_ON(has_group_leader_pid(tsk)); |
889 | /* |
890 | * An exec() starts a new thread group with the |
891 | * TGID of the previous thread group. Rehash the |
892 | * two threads with a switched PID, and release |
893 | * the former thread group leader: |
894 | */ |
895 | |
896 | /* Become a process group leader with the old leader's pid. |
897 | * The old leader becomes a thread of the this thread group. |
898 | * Note: The old leader also uses this pid until release_task |
899 | * is called. Odd but simple and correct. |
900 | */ |
901 | detach_pid(tsk, PIDTYPE_PID); |
902 | tsk->pid = leader->pid; |
903 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
904 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
905 | transfer_pid(leader, tsk, PIDTYPE_SID); |
906 | |
907 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
908 | list_replace_init(&leader->sibling, &tsk->sibling); |
909 | |
910 | tsk->group_leader = tsk; |
911 | leader->group_leader = tsk; |
912 | |
913 | tsk->exit_signal = SIGCHLD; |
914 | |
915 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); |
916 | leader->exit_state = EXIT_DEAD; |
917 | write_unlock_irq(&tasklist_lock); |
918 | |
919 | release_task(leader); |
920 | } |
921 | |
922 | sig->group_exit_task = NULL; |
923 | sig->notify_count = 0; |
924 | |
925 | no_thread_group: |
926 | if (current->mm) |
927 | setmax_mm_hiwater_rss(&sig->maxrss, current->mm); |
928 | |
929 | exit_itimers(sig); |
930 | flush_itimer_signals(); |
931 | |
932 | if (atomic_read(&oldsighand->count) != 1) { |
933 | struct sighand_struct *newsighand; |
934 | /* |
935 | * This ->sighand is shared with the CLONE_SIGHAND |
936 | * but not CLONE_THREAD task, switch to the new one. |
937 | */ |
938 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
939 | if (!newsighand) |
940 | return -ENOMEM; |
941 | |
942 | atomic_set(&newsighand->count, 1); |
943 | memcpy(newsighand->action, oldsighand->action, |
944 | sizeof(newsighand->action)); |
945 | |
946 | write_lock_irq(&tasklist_lock); |
947 | spin_lock(&oldsighand->siglock); |
948 | rcu_assign_pointer(tsk->sighand, newsighand); |
949 | spin_unlock(&oldsighand->siglock); |
950 | write_unlock_irq(&tasklist_lock); |
951 | |
952 | __cleanup_sighand(oldsighand); |
953 | } |
954 | |
955 | BUG_ON(!thread_group_leader(tsk)); |
956 | return 0; |
957 | } |
958 | |
959 | /* |
960 | * These functions flushes out all traces of the currently running executable |
961 | * so that a new one can be started |
962 | */ |
963 | static void flush_old_files(struct files_struct * files) |
964 | { |
965 | long j = -1; |
966 | struct fdtable *fdt; |
967 | |
968 | spin_lock(&files->file_lock); |
969 | for (;;) { |
970 | unsigned long set, i; |
971 | |
972 | j++; |
973 | i = j * __NFDBITS; |
974 | fdt = files_fdtable(files); |
975 | if (i >= fdt->max_fds) |
976 | break; |
977 | set = fdt->close_on_exec->fds_bits[j]; |
978 | if (!set) |
979 | continue; |
980 | fdt->close_on_exec->fds_bits[j] = 0; |
981 | spin_unlock(&files->file_lock); |
982 | for ( ; set ; i++,set >>= 1) { |
983 | if (set & 1) { |
984 | sys_close(i); |
985 | } |
986 | } |
987 | spin_lock(&files->file_lock); |
988 | |
989 | } |
990 | spin_unlock(&files->file_lock); |
991 | } |
992 | |
993 | char *get_task_comm(char *buf, struct task_struct *tsk) |
994 | { |
995 | /* buf must be at least sizeof(tsk->comm) in size */ |
996 | task_lock(tsk); |
997 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); |
998 | task_unlock(tsk); |
999 | return buf; |
1000 | } |
1001 | |
1002 | void set_task_comm(struct task_struct *tsk, char *buf) |
1003 | { |
1004 | task_lock(tsk); |
1005 | |
1006 | /* |
1007 | * Threads may access current->comm without holding |
1008 | * the task lock, so write the string carefully. |
1009 | * Readers without a lock may see incomplete new |
1010 | * names but are safe from non-terminating string reads. |
1011 | */ |
1012 | memset(tsk->comm, 0, TASK_COMM_LEN); |
1013 | wmb(); |
1014 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1015 | task_unlock(tsk); |
1016 | perf_event_comm(tsk); |
1017 | } |
1018 | |
1019 | int flush_old_exec(struct linux_binprm * bprm) |
1020 | { |
1021 | int retval; |
1022 | |
1023 | /* |
1024 | * Make sure we have a private signal table and that |
1025 | * we are unassociated from the previous thread group. |
1026 | */ |
1027 | retval = de_thread(current); |
1028 | if (retval) |
1029 | goto out; |
1030 | |
1031 | set_mm_exe_file(bprm->mm, bprm->file); |
1032 | |
1033 | /* |
1034 | * Release all of the old mmap stuff |
1035 | */ |
1036 | acct_arg_size(bprm, 0); |
1037 | retval = exec_mmap(bprm->mm); |
1038 | if (retval) |
1039 | goto out; |
1040 | |
1041 | bprm->mm = NULL; /* We're using it now */ |
1042 | |
1043 | current->flags &= ~(PF_RANDOMIZE | PF_KTHREAD); |
1044 | flush_thread(); |
1045 | current->personality &= ~bprm->per_clear; |
1046 | |
1047 | return 0; |
1048 | |
1049 | out: |
1050 | return retval; |
1051 | } |
1052 | EXPORT_SYMBOL(flush_old_exec); |
1053 | |
1054 | void setup_new_exec(struct linux_binprm * bprm) |
1055 | { |
1056 | int i, ch; |
1057 | const char *name; |
1058 | char tcomm[sizeof(current->comm)]; |
1059 | |
1060 | arch_pick_mmap_layout(current->mm); |
1061 | |
1062 | /* This is the point of no return */ |
1063 | current->sas_ss_sp = current->sas_ss_size = 0; |
1064 | |
1065 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
1066 | set_dumpable(current->mm, 1); |
1067 | else |
1068 | set_dumpable(current->mm, suid_dumpable); |
1069 | |
1070 | name = bprm->filename; |
1071 | |
1072 | /* Copies the binary name from after last slash */ |
1073 | for (i=0; (ch = *(name++)) != '\0';) { |
1074 | if (ch == '/') |
1075 | i = 0; /* overwrite what we wrote */ |
1076 | else |
1077 | if (i < (sizeof(tcomm) - 1)) |
1078 | tcomm[i++] = ch; |
1079 | } |
1080 | tcomm[i] = '\0'; |
1081 | set_task_comm(current, tcomm); |
1082 | |
1083 | /* Set the new mm task size. We have to do that late because it may |
1084 | * depend on TIF_32BIT which is only updated in flush_thread() on |
1085 | * some architectures like powerpc |
1086 | */ |
1087 | current->mm->task_size = TASK_SIZE; |
1088 | |
1089 | /* install the new credentials */ |
1090 | if (bprm->cred->uid != current_euid() || |
1091 | bprm->cred->gid != current_egid()) { |
1092 | current->pdeath_signal = 0; |
1093 | } else if (file_permission(bprm->file, MAY_READ) || |
1094 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
1095 | set_dumpable(current->mm, suid_dumpable); |
1096 | } |
1097 | |
1098 | /* |
1099 | * Flush performance counters when crossing a |
1100 | * security domain: |
1101 | */ |
1102 | if (!get_dumpable(current->mm)) |
1103 | perf_event_exit_task(current); |
1104 | |
1105 | /* An exec changes our domain. We are no longer part of the thread |
1106 | group */ |
1107 | |
1108 | current->self_exec_id++; |
1109 | |
1110 | flush_signal_handlers(current, 0); |
1111 | flush_old_files(current->files); |
1112 | } |
1113 | EXPORT_SYMBOL(setup_new_exec); |
1114 | |
1115 | /* |
1116 | * Prepare credentials and lock ->cred_guard_mutex. |
1117 | * install_exec_creds() commits the new creds and drops the lock. |
1118 | * Or, if exec fails before, free_bprm() should release ->cred and |
1119 | * and unlock. |
1120 | */ |
1121 | int prepare_bprm_creds(struct linux_binprm *bprm) |
1122 | { |
1123 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
1124 | return -ERESTARTNOINTR; |
1125 | |
1126 | bprm->cred = prepare_exec_creds(); |
1127 | if (likely(bprm->cred)) |
1128 | return 0; |
1129 | |
1130 | mutex_unlock(¤t->signal->cred_guard_mutex); |
1131 | return -ENOMEM; |
1132 | } |
1133 | |
1134 | void free_bprm(struct linux_binprm *bprm) |
1135 | { |
1136 | free_arg_pages(bprm); |
1137 | if (bprm->cred) { |
1138 | mutex_unlock(¤t->signal->cred_guard_mutex); |
1139 | abort_creds(bprm->cred); |
1140 | } |
1141 | kfree(bprm); |
1142 | } |
1143 | |
1144 | /* |
1145 | * install the new credentials for this executable |
1146 | */ |
1147 | void install_exec_creds(struct linux_binprm *bprm) |
1148 | { |
1149 | security_bprm_committing_creds(bprm); |
1150 | |
1151 | commit_creds(bprm->cred); |
1152 | bprm->cred = NULL; |
1153 | /* |
1154 | * cred_guard_mutex must be held at least to this point to prevent |
1155 | * ptrace_attach() from altering our determination of the task's |
1156 | * credentials; any time after this it may be unlocked. |
1157 | */ |
1158 | security_bprm_committed_creds(bprm); |
1159 | mutex_unlock(¤t->signal->cred_guard_mutex); |
1160 | } |
1161 | EXPORT_SYMBOL(install_exec_creds); |
1162 | |
1163 | /* |
1164 | * determine how safe it is to execute the proposed program |
1165 | * - the caller must hold ->cred_guard_mutex to protect against |
1166 | * PTRACE_ATTACH |
1167 | */ |
1168 | int check_unsafe_exec(struct linux_binprm *bprm) |
1169 | { |
1170 | struct task_struct *p = current, *t; |
1171 | unsigned n_fs; |
1172 | int res = 0; |
1173 | |
1174 | bprm->unsafe = tracehook_unsafe_exec(p); |
1175 | |
1176 | n_fs = 1; |
1177 | spin_lock(&p->fs->lock); |
1178 | rcu_read_lock(); |
1179 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
1180 | if (t->fs == p->fs) |
1181 | n_fs++; |
1182 | } |
1183 | rcu_read_unlock(); |
1184 | |
1185 | if (p->fs->users > n_fs) { |
1186 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
1187 | } else { |
1188 | res = -EAGAIN; |
1189 | if (!p->fs->in_exec) { |
1190 | p->fs->in_exec = 1; |
1191 | res = 1; |
1192 | } |
1193 | } |
1194 | spin_unlock(&p->fs->lock); |
1195 | |
1196 | return res; |
1197 | } |
1198 | |
1199 | /* |
1200 | * Fill the binprm structure from the inode. |
1201 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
1202 | * |
1203 | * This may be called multiple times for binary chains (scripts for example). |
1204 | */ |
1205 | int prepare_binprm(struct linux_binprm *bprm) |
1206 | { |
1207 | umode_t mode; |
1208 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1209 | int retval; |
1210 | |
1211 | mode = inode->i_mode; |
1212 | if (bprm->file->f_op == NULL) |
1213 | return -EACCES; |
1214 | |
1215 | /* clear any previous set[ug]id data from a previous binary */ |
1216 | bprm->cred->euid = current_euid(); |
1217 | bprm->cred->egid = current_egid(); |
1218 | |
1219 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1220 | /* Set-uid? */ |
1221 | if (mode & S_ISUID) { |
1222 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1223 | bprm->cred->euid = inode->i_uid; |
1224 | } |
1225 | |
1226 | /* Set-gid? */ |
1227 | /* |
1228 | * If setgid is set but no group execute bit then this |
1229 | * is a candidate for mandatory locking, not a setgid |
1230 | * executable. |
1231 | */ |
1232 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { |
1233 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1234 | bprm->cred->egid = inode->i_gid; |
1235 | } |
1236 | } |
1237 | |
1238 | /* fill in binprm security blob */ |
1239 | retval = security_bprm_set_creds(bprm); |
1240 | if (retval) |
1241 | return retval; |
1242 | bprm->cred_prepared = 1; |
1243 | |
1244 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1245 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
1246 | } |
1247 | |
1248 | EXPORT_SYMBOL(prepare_binprm); |
1249 | |
1250 | /* |
1251 | * Arguments are '\0' separated strings found at the location bprm->p |
1252 | * points to; chop off the first by relocating brpm->p to right after |
1253 | * the first '\0' encountered. |
1254 | */ |
1255 | int remove_arg_zero(struct linux_binprm *bprm) |
1256 | { |
1257 | int ret = 0; |
1258 | unsigned long offset; |
1259 | char *kaddr; |
1260 | struct page *page; |
1261 | |
1262 | if (!bprm->argc) |
1263 | return 0; |
1264 | |
1265 | do { |
1266 | offset = bprm->p & ~PAGE_MASK; |
1267 | page = get_arg_page(bprm, bprm->p, 0); |
1268 | if (!page) { |
1269 | ret = -EFAULT; |
1270 | goto out; |
1271 | } |
1272 | kaddr = kmap_atomic(page, KM_USER0); |
1273 | |
1274 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1275 | offset++, bprm->p++) |
1276 | ; |
1277 | |
1278 | kunmap_atomic(kaddr, KM_USER0); |
1279 | put_arg_page(page); |
1280 | |
1281 | if (offset == PAGE_SIZE) |
1282 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); |
1283 | } while (offset == PAGE_SIZE); |
1284 | |
1285 | bprm->p++; |
1286 | bprm->argc--; |
1287 | ret = 0; |
1288 | |
1289 | out: |
1290 | return ret; |
1291 | } |
1292 | EXPORT_SYMBOL(remove_arg_zero); |
1293 | |
1294 | /* |
1295 | * cycle the list of binary formats handler, until one recognizes the image |
1296 | */ |
1297 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) |
1298 | { |
1299 | unsigned int depth = bprm->recursion_depth; |
1300 | int try,retval; |
1301 | struct linux_binfmt *fmt; |
1302 | |
1303 | retval = security_bprm_check(bprm); |
1304 | if (retval) |
1305 | return retval; |
1306 | |
1307 | /* kernel module loader fixup */ |
1308 | /* so we don't try to load run modprobe in kernel space. */ |
1309 | set_fs(USER_DS); |
1310 | |
1311 | retval = audit_bprm(bprm); |
1312 | if (retval) |
1313 | return retval; |
1314 | |
1315 | retval = -ENOENT; |
1316 | for (try=0; try<2; try++) { |
1317 | read_lock(&binfmt_lock); |
1318 | list_for_each_entry(fmt, &formats, lh) { |
1319 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1320 | if (!fn) |
1321 | continue; |
1322 | if (!try_module_get(fmt->module)) |
1323 | continue; |
1324 | read_unlock(&binfmt_lock); |
1325 | retval = fn(bprm, regs); |
1326 | /* |
1327 | * Restore the depth counter to its starting value |
1328 | * in this call, so we don't have to rely on every |
1329 | * load_binary function to restore it on return. |
1330 | */ |
1331 | bprm->recursion_depth = depth; |
1332 | if (retval >= 0) { |
1333 | if (depth == 0) |
1334 | tracehook_report_exec(fmt, bprm, regs); |
1335 | put_binfmt(fmt); |
1336 | allow_write_access(bprm->file); |
1337 | if (bprm->file) |
1338 | fput(bprm->file); |
1339 | bprm->file = NULL; |
1340 | current->did_exec = 1; |
1341 | proc_exec_connector(current); |
1342 | return retval; |
1343 | } |
1344 | read_lock(&binfmt_lock); |
1345 | put_binfmt(fmt); |
1346 | if (retval != -ENOEXEC || bprm->mm == NULL) |
1347 | break; |
1348 | if (!bprm->file) { |
1349 | read_unlock(&binfmt_lock); |
1350 | return retval; |
1351 | } |
1352 | } |
1353 | read_unlock(&binfmt_lock); |
1354 | if (retval != -ENOEXEC || bprm->mm == NULL) { |
1355 | break; |
1356 | #ifdef CONFIG_MODULES |
1357 | } else { |
1358 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1359 | if (printable(bprm->buf[0]) && |
1360 | printable(bprm->buf[1]) && |
1361 | printable(bprm->buf[2]) && |
1362 | printable(bprm->buf[3])) |
1363 | break; /* -ENOEXEC */ |
1364 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); |
1365 | #endif |
1366 | } |
1367 | } |
1368 | return retval; |
1369 | } |
1370 | |
1371 | EXPORT_SYMBOL(search_binary_handler); |
1372 | |
1373 | /* |
1374 | * sys_execve() executes a new program. |
1375 | */ |
1376 | int do_execve(const char * filename, |
1377 | const char __user *const __user *argv, |
1378 | const char __user *const __user *envp, |
1379 | struct pt_regs * regs) |
1380 | { |
1381 | struct linux_binprm *bprm; |
1382 | struct file *file; |
1383 | struct files_struct *displaced; |
1384 | bool clear_in_exec; |
1385 | int retval; |
1386 | |
1387 | retval = unshare_files(&displaced); |
1388 | if (retval) |
1389 | goto out_ret; |
1390 | |
1391 | retval = -ENOMEM; |
1392 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1393 | if (!bprm) |
1394 | goto out_files; |
1395 | |
1396 | retval = prepare_bprm_creds(bprm); |
1397 | if (retval) |
1398 | goto out_free; |
1399 | |
1400 | retval = check_unsafe_exec(bprm); |
1401 | if (retval < 0) |
1402 | goto out_free; |
1403 | clear_in_exec = retval; |
1404 | current->in_execve = 1; |
1405 | |
1406 | file = open_exec(filename); |
1407 | retval = PTR_ERR(file); |
1408 | if (IS_ERR(file)) |
1409 | goto out_unmark; |
1410 | |
1411 | sched_exec(); |
1412 | |
1413 | bprm->file = file; |
1414 | bprm->filename = filename; |
1415 | bprm->interp = filename; |
1416 | |
1417 | retval = bprm_mm_init(bprm); |
1418 | if (retval) |
1419 | goto out_file; |
1420 | |
1421 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1422 | if ((retval = bprm->argc) < 0) |
1423 | goto out; |
1424 | |
1425 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1426 | if ((retval = bprm->envc) < 0) |
1427 | goto out; |
1428 | |
1429 | retval = prepare_binprm(bprm); |
1430 | if (retval < 0) |
1431 | goto out; |
1432 | |
1433 | retval = copy_strings_kernel(1, &bprm->filename, bprm); |
1434 | if (retval < 0) |
1435 | goto out; |
1436 | |
1437 | bprm->exec = bprm->p; |
1438 | retval = copy_strings(bprm->envc, envp, bprm); |
1439 | if (retval < 0) |
1440 | goto out; |
1441 | |
1442 | retval = copy_strings(bprm->argc, argv, bprm); |
1443 | if (retval < 0) |
1444 | goto out; |
1445 | |
1446 | retval = search_binary_handler(bprm,regs); |
1447 | if (retval < 0) |
1448 | goto out; |
1449 | |
1450 | /* execve succeeded */ |
1451 | current->fs->in_exec = 0; |
1452 | current->in_execve = 0; |
1453 | acct_update_integrals(current); |
1454 | free_bprm(bprm); |
1455 | if (displaced) |
1456 | put_files_struct(displaced); |
1457 | return retval; |
1458 | |
1459 | out: |
1460 | if (bprm->mm) { |
1461 | acct_arg_size(bprm, 0); |
1462 | mmput(bprm->mm); |
1463 | } |
1464 | |
1465 | out_file: |
1466 | if (bprm->file) { |
1467 | allow_write_access(bprm->file); |
1468 | fput(bprm->file); |
1469 | } |
1470 | |
1471 | out_unmark: |
1472 | if (clear_in_exec) |
1473 | current->fs->in_exec = 0; |
1474 | current->in_execve = 0; |
1475 | |
1476 | out_free: |
1477 | free_bprm(bprm); |
1478 | |
1479 | out_files: |
1480 | if (displaced) |
1481 | reset_files_struct(displaced); |
1482 | out_ret: |
1483 | return retval; |
1484 | } |
1485 | |
1486 | void set_binfmt(struct linux_binfmt *new) |
1487 | { |
1488 | struct mm_struct *mm = current->mm; |
1489 | |
1490 | if (mm->binfmt) |
1491 | module_put(mm->binfmt->module); |
1492 | |
1493 | mm->binfmt = new; |
1494 | if (new) |
1495 | __module_get(new->module); |
1496 | } |
1497 | |
1498 | EXPORT_SYMBOL(set_binfmt); |
1499 | |
1500 | static int expand_corename(struct core_name *cn) |
1501 | { |
1502 | char *old_corename = cn->corename; |
1503 | |
1504 | cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); |
1505 | cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL); |
1506 | |
1507 | if (!cn->corename) { |
1508 | kfree(old_corename); |
1509 | return -ENOMEM; |
1510 | } |
1511 | |
1512 | return 0; |
1513 | } |
1514 | |
1515 | static int cn_printf(struct core_name *cn, const char *fmt, ...) |
1516 | { |
1517 | char *cur; |
1518 | int need; |
1519 | int ret; |
1520 | va_list arg; |
1521 | |
1522 | va_start(arg, fmt); |
1523 | need = vsnprintf(NULL, 0, fmt, arg); |
1524 | va_end(arg); |
1525 | |
1526 | if (likely(need < cn->size - cn->used - 1)) |
1527 | goto out_printf; |
1528 | |
1529 | ret = expand_corename(cn); |
1530 | if (ret) |
1531 | goto expand_fail; |
1532 | |
1533 | out_printf: |
1534 | cur = cn->corename + cn->used; |
1535 | va_start(arg, fmt); |
1536 | vsnprintf(cur, need + 1, fmt, arg); |
1537 | va_end(arg); |
1538 | cn->used += need; |
1539 | return 0; |
1540 | |
1541 | expand_fail: |
1542 | return ret; |
1543 | } |
1544 | |
1545 | /* format_corename will inspect the pattern parameter, and output a |
1546 | * name into corename, which must have space for at least |
1547 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. |
1548 | */ |
1549 | static int format_corename(struct core_name *cn, long signr) |
1550 | { |
1551 | const struct cred *cred = current_cred(); |
1552 | const char *pat_ptr = core_pattern; |
1553 | int ispipe = (*pat_ptr == '|'); |
1554 | int pid_in_pattern = 0; |
1555 | int err = 0; |
1556 | |
1557 | cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); |
1558 | cn->corename = kmalloc(cn->size, GFP_KERNEL); |
1559 | cn->used = 0; |
1560 | |
1561 | if (!cn->corename) |
1562 | return -ENOMEM; |
1563 | |
1564 | /* Repeat as long as we have more pattern to process and more output |
1565 | space */ |
1566 | while (*pat_ptr) { |
1567 | if (*pat_ptr != '%') { |
1568 | if (*pat_ptr == 0) |
1569 | goto out; |
1570 | err = cn_printf(cn, "%c", *pat_ptr++); |
1571 | } else { |
1572 | switch (*++pat_ptr) { |
1573 | /* single % at the end, drop that */ |
1574 | case 0: |
1575 | goto out; |
1576 | /* Double percent, output one percent */ |
1577 | case '%': |
1578 | err = cn_printf(cn, "%c", '%'); |
1579 | break; |
1580 | /* pid */ |
1581 | case 'p': |
1582 | pid_in_pattern = 1; |
1583 | err = cn_printf(cn, "%d", |
1584 | task_tgid_vnr(current)); |
1585 | break; |
1586 | /* uid */ |
1587 | case 'u': |
1588 | err = cn_printf(cn, "%d", cred->uid); |
1589 | break; |
1590 | /* gid */ |
1591 | case 'g': |
1592 | err = cn_printf(cn, "%d", cred->gid); |
1593 | break; |
1594 | /* signal that caused the coredump */ |
1595 | case 's': |
1596 | err = cn_printf(cn, "%ld", signr); |
1597 | break; |
1598 | /* UNIX time of coredump */ |
1599 | case 't': { |
1600 | struct timeval tv; |
1601 | do_gettimeofday(&tv); |
1602 | err = cn_printf(cn, "%lu", tv.tv_sec); |
1603 | break; |
1604 | } |
1605 | /* hostname */ |
1606 | case 'h': |
1607 | down_read(&uts_sem); |
1608 | err = cn_printf(cn, "%s", |
1609 | utsname()->nodename); |
1610 | up_read(&uts_sem); |
1611 | break; |
1612 | /* executable */ |
1613 | case 'e': |
1614 | err = cn_printf(cn, "%s", current->comm); |
1615 | break; |
1616 | /* core limit size */ |
1617 | case 'c': |
1618 | err = cn_printf(cn, "%lu", |
1619 | rlimit(RLIMIT_CORE)); |
1620 | break; |
1621 | default: |
1622 | break; |
1623 | } |
1624 | ++pat_ptr; |
1625 | } |
1626 | |
1627 | if (err) |
1628 | return err; |
1629 | } |
1630 | |
1631 | /* Backward compatibility with core_uses_pid: |
1632 | * |
1633 | * If core_pattern does not include a %p (as is the default) |
1634 | * and core_uses_pid is set, then .%pid will be appended to |
1635 | * the filename. Do not do this for piped commands. */ |
1636 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1637 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); |
1638 | if (err) |
1639 | return err; |
1640 | } |
1641 | out: |
1642 | return ispipe; |
1643 | } |
1644 | |
1645 | static int zap_process(struct task_struct *start, int exit_code) |
1646 | { |
1647 | struct task_struct *t; |
1648 | int nr = 0; |
1649 | |
1650 | start->signal->flags = SIGNAL_GROUP_EXIT; |
1651 | start->signal->group_exit_code = exit_code; |
1652 | start->signal->group_stop_count = 0; |
1653 | |
1654 | t = start; |
1655 | do { |
1656 | if (t != current && t->mm) { |
1657 | sigaddset(&t->pending.signal, SIGKILL); |
1658 | signal_wake_up(t, 1); |
1659 | nr++; |
1660 | } |
1661 | } while_each_thread(start, t); |
1662 | |
1663 | return nr; |
1664 | } |
1665 | |
1666 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
1667 | struct core_state *core_state, int exit_code) |
1668 | { |
1669 | struct task_struct *g, *p; |
1670 | unsigned long flags; |
1671 | int nr = -EAGAIN; |
1672 | |
1673 | spin_lock_irq(&tsk->sighand->siglock); |
1674 | if (!signal_group_exit(tsk->signal)) { |
1675 | mm->core_state = core_state; |
1676 | nr = zap_process(tsk, exit_code); |
1677 | } |
1678 | spin_unlock_irq(&tsk->sighand->siglock); |
1679 | if (unlikely(nr < 0)) |
1680 | return nr; |
1681 | |
1682 | if (atomic_read(&mm->mm_users) == nr + 1) |
1683 | goto done; |
1684 | /* |
1685 | * We should find and kill all tasks which use this mm, and we should |
1686 | * count them correctly into ->nr_threads. We don't take tasklist |
1687 | * lock, but this is safe wrt: |
1688 | * |
1689 | * fork: |
1690 | * None of sub-threads can fork after zap_process(leader). All |
1691 | * processes which were created before this point should be |
1692 | * visible to zap_threads() because copy_process() adds the new |
1693 | * process to the tail of init_task.tasks list, and lock/unlock |
1694 | * of ->siglock provides a memory barrier. |
1695 | * |
1696 | * do_exit: |
1697 | * The caller holds mm->mmap_sem. This means that the task which |
1698 | * uses this mm can't pass exit_mm(), so it can't exit or clear |
1699 | * its ->mm. |
1700 | * |
1701 | * de_thread: |
1702 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), |
1703 | * we must see either old or new leader, this does not matter. |
1704 | * However, it can change p->sighand, so lock_task_sighand(p) |
1705 | * must be used. Since p->mm != NULL and we hold ->mmap_sem |
1706 | * it can't fail. |
1707 | * |
1708 | * Note also that "g" can be the old leader with ->mm == NULL |
1709 | * and already unhashed and thus removed from ->thread_group. |
1710 | * This is OK, __unhash_process()->list_del_rcu() does not |
1711 | * clear the ->next pointer, we will find the new leader via |
1712 | * next_thread(). |
1713 | */ |
1714 | rcu_read_lock(); |
1715 | for_each_process(g) { |
1716 | if (g == tsk->group_leader) |
1717 | continue; |
1718 | if (g->flags & PF_KTHREAD) |
1719 | continue; |
1720 | p = g; |
1721 | do { |
1722 | if (p->mm) { |
1723 | if (unlikely(p->mm == mm)) { |
1724 | lock_task_sighand(p, &flags); |
1725 | nr += zap_process(p, exit_code); |
1726 | unlock_task_sighand(p, &flags); |
1727 | } |
1728 | break; |
1729 | } |
1730 | } while_each_thread(g, p); |
1731 | } |
1732 | rcu_read_unlock(); |
1733 | done: |
1734 | atomic_set(&core_state->nr_threads, nr); |
1735 | return nr; |
1736 | } |
1737 | |
1738 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1739 | { |
1740 | struct task_struct *tsk = current; |
1741 | struct mm_struct *mm = tsk->mm; |
1742 | struct completion *vfork_done; |
1743 | int core_waiters = -EBUSY; |
1744 | |
1745 | init_completion(&core_state->startup); |
1746 | core_state->dumper.task = tsk; |
1747 | core_state->dumper.next = NULL; |
1748 | |
1749 | down_write(&mm->mmap_sem); |
1750 | if (!mm->core_state) |
1751 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
1752 | up_write(&mm->mmap_sem); |
1753 | |
1754 | if (unlikely(core_waiters < 0)) |
1755 | goto fail; |
1756 | |
1757 | /* |
1758 | * Make sure nobody is waiting for us to release the VM, |
1759 | * otherwise we can deadlock when we wait on each other |
1760 | */ |
1761 | vfork_done = tsk->vfork_done; |
1762 | if (vfork_done) { |
1763 | tsk->vfork_done = NULL; |
1764 | complete(vfork_done); |
1765 | } |
1766 | |
1767 | if (core_waiters) |
1768 | wait_for_completion(&core_state->startup); |
1769 | fail: |
1770 | return core_waiters; |
1771 | } |
1772 | |
1773 | static void coredump_finish(struct mm_struct *mm) |
1774 | { |
1775 | struct core_thread *curr, *next; |
1776 | struct task_struct *task; |
1777 | |
1778 | next = mm->core_state->dumper.next; |
1779 | while ((curr = next) != NULL) { |
1780 | next = curr->next; |
1781 | task = curr->task; |
1782 | /* |
1783 | * see exit_mm(), curr->task must not see |
1784 | * ->task == NULL before we read ->next. |
1785 | */ |
1786 | smp_mb(); |
1787 | curr->task = NULL; |
1788 | wake_up_process(task); |
1789 | } |
1790 | |
1791 | mm->core_state = NULL; |
1792 | } |
1793 | |
1794 | /* |
1795 | * set_dumpable converts traditional three-value dumpable to two flags and |
1796 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but |
1797 | * these bits are not changed atomically. So get_dumpable can observe the |
1798 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable |
1799 | * return either old dumpable or new one by paying attention to the order of |
1800 | * modifying the bits. |
1801 | * |
1802 | * dumpable | mm->flags (binary) |
1803 | * old new | initial interim final |
1804 | * ---------+----------------------- |
1805 | * 0 1 | 00 01 01 |
1806 | * 0 2 | 00 10(*) 11 |
1807 | * 1 0 | 01 00 00 |
1808 | * 1 2 | 01 11 11 |
1809 | * 2 0 | 11 10(*) 00 |
1810 | * 2 1 | 11 11 01 |
1811 | * |
1812 | * (*) get_dumpable regards interim value of 10 as 11. |
1813 | */ |
1814 | void set_dumpable(struct mm_struct *mm, int value) |
1815 | { |
1816 | switch (value) { |
1817 | case 0: |
1818 | clear_bit(MMF_DUMPABLE, &mm->flags); |
1819 | smp_wmb(); |
1820 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
1821 | break; |
1822 | case 1: |
1823 | set_bit(MMF_DUMPABLE, &mm->flags); |
1824 | smp_wmb(); |
1825 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
1826 | break; |
1827 | case 2: |
1828 | set_bit(MMF_DUMP_SECURELY, &mm->flags); |
1829 | smp_wmb(); |
1830 | set_bit(MMF_DUMPABLE, &mm->flags); |
1831 | break; |
1832 | } |
1833 | } |
1834 | |
1835 | static int __get_dumpable(unsigned long mm_flags) |
1836 | { |
1837 | int ret; |
1838 | |
1839 | ret = mm_flags & MMF_DUMPABLE_MASK; |
1840 | return (ret >= 2) ? 2 : ret; |
1841 | } |
1842 | |
1843 | int get_dumpable(struct mm_struct *mm) |
1844 | { |
1845 | return __get_dumpable(mm->flags); |
1846 | } |
1847 | |
1848 | static void wait_for_dump_helpers(struct file *file) |
1849 | { |
1850 | struct pipe_inode_info *pipe; |
1851 | |
1852 | pipe = file->f_path.dentry->d_inode->i_pipe; |
1853 | |
1854 | pipe_lock(pipe); |
1855 | pipe->readers++; |
1856 | pipe->writers--; |
1857 | |
1858 | while ((pipe->readers > 1) && (!signal_pending(current))) { |
1859 | wake_up_interruptible_sync(&pipe->wait); |
1860 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
1861 | pipe_wait(pipe); |
1862 | } |
1863 | |
1864 | pipe->readers--; |
1865 | pipe->writers++; |
1866 | pipe_unlock(pipe); |
1867 | |
1868 | } |
1869 | |
1870 | |
1871 | /* |
1872 | * uhm_pipe_setup |
1873 | * helper function to customize the process used |
1874 | * to collect the core in userspace. Specifically |
1875 | * it sets up a pipe and installs it as fd 0 (stdin) |
1876 | * for the process. Returns 0 on success, or |
1877 | * PTR_ERR on failure. |
1878 | * Note that it also sets the core limit to 1. This |
1879 | * is a special value that we use to trap recursive |
1880 | * core dumps |
1881 | */ |
1882 | static int umh_pipe_setup(struct subprocess_info *info) |
1883 | { |
1884 | struct file *rp, *wp; |
1885 | struct fdtable *fdt; |
1886 | struct coredump_params *cp = (struct coredump_params *)info->data; |
1887 | struct files_struct *cf = current->files; |
1888 | |
1889 | wp = create_write_pipe(0); |
1890 | if (IS_ERR(wp)) |
1891 | return PTR_ERR(wp); |
1892 | |
1893 | rp = create_read_pipe(wp, 0); |
1894 | if (IS_ERR(rp)) { |
1895 | free_write_pipe(wp); |
1896 | return PTR_ERR(rp); |
1897 | } |
1898 | |
1899 | cp->file = wp; |
1900 | |
1901 | sys_close(0); |
1902 | fd_install(0, rp); |
1903 | spin_lock(&cf->file_lock); |
1904 | fdt = files_fdtable(cf); |
1905 | FD_SET(0, fdt->open_fds); |
1906 | FD_CLR(0, fdt->close_on_exec); |
1907 | spin_unlock(&cf->file_lock); |
1908 | |
1909 | /* and disallow core files too */ |
1910 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; |
1911 | |
1912 | return 0; |
1913 | } |
1914 | |
1915 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1916 | { |
1917 | struct core_state core_state; |
1918 | struct core_name cn; |
1919 | struct mm_struct *mm = current->mm; |
1920 | struct linux_binfmt * binfmt; |
1921 | const struct cred *old_cred; |
1922 | struct cred *cred; |
1923 | int retval = 0; |
1924 | int flag = 0; |
1925 | int ispipe; |
1926 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
1927 | struct coredump_params cprm = { |
1928 | .signr = signr, |
1929 | .regs = regs, |
1930 | .limit = rlimit(RLIMIT_CORE), |
1931 | /* |
1932 | * We must use the same mm->flags while dumping core to avoid |
1933 | * inconsistency of bit flags, since this flag is not protected |
1934 | * by any locks. |
1935 | */ |
1936 | .mm_flags = mm->flags, |
1937 | }; |
1938 | |
1939 | audit_core_dumps(signr); |
1940 | |
1941 | binfmt = mm->binfmt; |
1942 | if (!binfmt || !binfmt->core_dump) |
1943 | goto fail; |
1944 | if (!__get_dumpable(cprm.mm_flags)) |
1945 | goto fail; |
1946 | |
1947 | cred = prepare_creds(); |
1948 | if (!cred) |
1949 | goto fail; |
1950 | /* |
1951 | * We cannot trust fsuid as being the "true" uid of the |
1952 | * process nor do we know its entire history. We only know it |
1953 | * was tainted so we dump it as root in mode 2. |
1954 | */ |
1955 | if (__get_dumpable(cprm.mm_flags) == 2) { |
1956 | /* Setuid core dump mode */ |
1957 | flag = O_EXCL; /* Stop rewrite attacks */ |
1958 | cred->fsuid = 0; /* Dump root private */ |
1959 | } |
1960 | |
1961 | retval = coredump_wait(exit_code, &core_state); |
1962 | if (retval < 0) |
1963 | goto fail_creds; |
1964 | |
1965 | old_cred = override_creds(cred); |
1966 | |
1967 | /* |
1968 | * Clear any false indication of pending signals that might |
1969 | * be seen by the filesystem code called to write the core file. |
1970 | */ |
1971 | clear_thread_flag(TIF_SIGPENDING); |
1972 | |
1973 | ispipe = format_corename(&cn, signr); |
1974 | |
1975 | if (ispipe == -ENOMEM) { |
1976 | printk(KERN_WARNING "format_corename failed\n"); |
1977 | printk(KERN_WARNING "Aborting core\n"); |
1978 | goto fail_corename; |
1979 | } |
1980 | |
1981 | if (ispipe) { |
1982 | int dump_count; |
1983 | char **helper_argv; |
1984 | |
1985 | if (cprm.limit == 1) { |
1986 | /* |
1987 | * Normally core limits are irrelevant to pipes, since |
1988 | * we're not writing to the file system, but we use |
1989 | * cprm.limit of 1 here as a speacial value. Any |
1990 | * non-1 limit gets set to RLIM_INFINITY below, but |
1991 | * a limit of 0 skips the dump. This is a consistent |
1992 | * way to catch recursive crashes. We can still crash |
1993 | * if the core_pattern binary sets RLIM_CORE = !1 |
1994 | * but it runs as root, and can do lots of stupid things |
1995 | * Note that we use task_tgid_vnr here to grab the pid |
1996 | * of the process group leader. That way we get the |
1997 | * right pid if a thread in a multi-threaded |
1998 | * core_pattern process dies. |
1999 | */ |
2000 | printk(KERN_WARNING |
2001 | "Process %d(%s) has RLIMIT_CORE set to 1\n", |
2002 | task_tgid_vnr(current), current->comm); |
2003 | printk(KERN_WARNING "Aborting core\n"); |
2004 | goto fail_unlock; |
2005 | } |
2006 | cprm.limit = RLIM_INFINITY; |
2007 | |
2008 | dump_count = atomic_inc_return(&core_dump_count); |
2009 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { |
2010 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", |
2011 | task_tgid_vnr(current), current->comm); |
2012 | printk(KERN_WARNING "Skipping core dump\n"); |
2013 | goto fail_dropcount; |
2014 | } |
2015 | |
2016 | helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); |
2017 | if (!helper_argv) { |
2018 | printk(KERN_WARNING "%s failed to allocate memory\n", |
2019 | __func__); |
2020 | goto fail_dropcount; |
2021 | } |
2022 | |
2023 | retval = call_usermodehelper_fns(helper_argv[0], helper_argv, |
2024 | NULL, UMH_WAIT_EXEC, umh_pipe_setup, |
2025 | NULL, &cprm); |
2026 | argv_free(helper_argv); |
2027 | if (retval) { |
2028 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
2029 | cn.corename); |
2030 | goto close_fail; |
2031 | } |
2032 | } else { |
2033 | struct inode *inode; |
2034 | |
2035 | if (cprm.limit < binfmt->min_coredump) |
2036 | goto fail_unlock; |
2037 | |
2038 | cprm.file = filp_open(cn.corename, |
2039 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
2040 | 0600); |
2041 | if (IS_ERR(cprm.file)) |
2042 | goto fail_unlock; |
2043 | |
2044 | inode = cprm.file->f_path.dentry->d_inode; |
2045 | if (inode->i_nlink > 1) |
2046 | goto close_fail; |
2047 | if (d_unhashed(cprm.file->f_path.dentry)) |
2048 | goto close_fail; |
2049 | /* |
2050 | * AK: actually i see no reason to not allow this for named |
2051 | * pipes etc, but keep the previous behaviour for now. |
2052 | */ |
2053 | if (!S_ISREG(inode->i_mode)) |
2054 | goto close_fail; |
2055 | /* |
2056 | * Dont allow local users get cute and trick others to coredump |
2057 | * into their pre-created files. |
2058 | */ |
2059 | if (inode->i_uid != current_fsuid()) |
2060 | goto close_fail; |
2061 | if (!cprm.file->f_op || !cprm.file->f_op->write) |
2062 | goto close_fail; |
2063 | if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) |
2064 | goto close_fail; |
2065 | } |
2066 | |
2067 | retval = binfmt->core_dump(&cprm); |
2068 | if (retval) |
2069 | current->signal->group_exit_code |= 0x80; |
2070 | |
2071 | if (ispipe && core_pipe_limit) |
2072 | wait_for_dump_helpers(cprm.file); |
2073 | close_fail: |
2074 | if (cprm.file) |
2075 | filp_close(cprm.file, NULL); |
2076 | fail_dropcount: |
2077 | if (ispipe) |
2078 | atomic_dec(&core_dump_count); |
2079 | fail_unlock: |
2080 | kfree(cn.corename); |
2081 | fail_corename: |
2082 | coredump_finish(mm); |
2083 | revert_creds(old_cred); |
2084 | fail_creds: |
2085 | put_cred(cred); |
2086 | fail: |
2087 | return; |
2088 | } |
2089 | |
2090 | /* |
2091 | * Core dumping helper functions. These are the only things you should |
2092 | * do on a core-file: use only these functions to write out all the |
2093 | * necessary info. |
2094 | */ |
2095 | int dump_write(struct file *file, const void *addr, int nr) |
2096 | { |
2097 | return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; |
2098 | } |
2099 | EXPORT_SYMBOL(dump_write); |
2100 | |
2101 | int dump_seek(struct file *file, loff_t off) |
2102 | { |
2103 | int ret = 1; |
2104 | |
2105 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { |
2106 | if (file->f_op->llseek(file, off, SEEK_CUR) < 0) |
2107 | return 0; |
2108 | } else { |
2109 | char *buf = (char *)get_zeroed_page(GFP_KERNEL); |
2110 | |
2111 | if (!buf) |
2112 | return 0; |
2113 | while (off > 0) { |
2114 | unsigned long n = off; |
2115 | |
2116 | if (n > PAGE_SIZE) |
2117 | n = PAGE_SIZE; |
2118 | if (!dump_write(file, buf, n)) { |
2119 | ret = 0; |
2120 | break; |
2121 | } |
2122 | off -= n; |
2123 | } |
2124 | free_page((unsigned long)buf); |
2125 | } |
2126 | return ret; |
2127 | } |
2128 | EXPORT_SYMBOL(dump_seek); |
2129 |
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