Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | ||
1da177e4 LT |
25 | #include <linux/slab.h> |
26 | #include <linux/file.h> | |
9f3acc31 | 27 | #include <linux/fdtable.h> |
ba92a43d | 28 | #include <linux/mm.h> |
1da177e4 LT |
29 | #include <linux/stat.h> |
30 | #include <linux/fcntl.h> | |
ba92a43d | 31 | #include <linux/swap.h> |
74aadce9 | 32 | #include <linux/string.h> |
1da177e4 | 33 | #include <linux/init.h> |
ca5b172b | 34 | #include <linux/pagemap.h> |
cdd6c482 | 35 | #include <linux/perf_event.h> |
1da177e4 LT |
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> | |
1da177e4 | 41 | #include <linux/utsname.h> |
84d73786 | 42 | #include <linux/pid_namespace.h> |
1da177e4 LT |
43 | #include <linux/module.h> |
44 | #include <linux/namei.h> | |
45 | #include <linux/proc_fs.h> | |
1da177e4 LT |
46 | #include <linux/mount.h> |
47 | #include <linux/security.h> | |
48 | #include <linux/syscalls.h> | |
8f0ab514 | 49 | #include <linux/tsacct_kern.h> |
9f46080c | 50 | #include <linux/cn_proc.h> |
473ae30b | 51 | #include <linux/audit.h> |
6341c393 | 52 | #include <linux/tracehook.h> |
5f4123be | 53 | #include <linux/kmod.h> |
6110e3ab | 54 | #include <linux/fsnotify.h> |
5ad4e53b | 55 | #include <linux/fs_struct.h> |
61be228a | 56 | #include <linux/pipe_fs_i.h> |
1da177e4 LT |
57 | |
58 | #include <asm/uaccess.h> | |
59 | #include <asm/mmu_context.h> | |
b6a2fea3 | 60 | #include <asm/tlb.h> |
a6f76f23 | 61 | #include "internal.h" |
1da177e4 | 62 | |
1da177e4 | 63 | int core_uses_pid; |
71ce92f3 | 64 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
a293980c | 65 | unsigned int core_pipe_limit; |
d6e71144 AC |
66 | int suid_dumpable = 0; |
67 | ||
1da177e4 LT |
68 | /* The maximal length of core_pattern is also specified in sysctl.c */ |
69 | ||
e4dc1b14 | 70 | static LIST_HEAD(formats); |
1da177e4 LT |
71 | static DEFINE_RWLOCK(binfmt_lock); |
72 | ||
74641f58 | 73 | int __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 74 | { |
1da177e4 LT |
75 | if (!fmt) |
76 | return -EINVAL; | |
1da177e4 | 77 | write_lock(&binfmt_lock); |
74641f58 IK |
78 | insert ? list_add(&fmt->lh, &formats) : |
79 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 LT |
80 | write_unlock(&binfmt_lock); |
81 | return 0; | |
82 | } | |
83 | ||
74641f58 | 84 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 85 | |
f6b450d4 | 86 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 87 | { |
1da177e4 | 88 | write_lock(&binfmt_lock); |
e4dc1b14 | 89 | list_del(&fmt->lh); |
1da177e4 | 90 | write_unlock(&binfmt_lock); |
1da177e4 LT |
91 | } |
92 | ||
93 | EXPORT_SYMBOL(unregister_binfmt); | |
94 | ||
95 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
96 | { | |
97 | module_put(fmt->module); | |
98 | } | |
99 | ||
100 | /* | |
101 | * Note that a shared library must be both readable and executable due to | |
102 | * security reasons. | |
103 | * | |
104 | * Also note that we take the address to load from from the file itself. | |
105 | */ | |
1e7bfb21 | 106 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 107 | { |
964bd183 | 108 | struct file *file; |
964bd183 AV |
109 | char *tmp = getname(library); |
110 | int error = PTR_ERR(tmp); | |
111 | ||
6e8341a1 AV |
112 | if (IS_ERR(tmp)) |
113 | goto out; | |
114 | ||
115 | file = do_filp_open(AT_FDCWD, tmp, | |
116 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
117 | MAY_READ | MAY_EXEC | MAY_OPEN); | |
118 | putname(tmp); | |
119 | error = PTR_ERR(file); | |
120 | if (IS_ERR(file)) | |
1da177e4 LT |
121 | goto out; |
122 | ||
123 | error = -EINVAL; | |
6e8341a1 | 124 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
1da177e4 LT |
125 | goto exit; |
126 | ||
30524472 | 127 | error = -EACCES; |
6e8341a1 | 128 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
1da177e4 LT |
129 | goto exit; |
130 | ||
2a12a9d7 | 131 | fsnotify_open(file); |
6110e3ab | 132 | |
1da177e4 LT |
133 | error = -ENOEXEC; |
134 | if(file->f_op) { | |
135 | struct linux_binfmt * fmt; | |
136 | ||
137 | read_lock(&binfmt_lock); | |
e4dc1b14 | 138 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
139 | if (!fmt->load_shlib) |
140 | continue; | |
141 | if (!try_module_get(fmt->module)) | |
142 | continue; | |
143 | read_unlock(&binfmt_lock); | |
144 | error = fmt->load_shlib(file); | |
145 | read_lock(&binfmt_lock); | |
146 | put_binfmt(fmt); | |
147 | if (error != -ENOEXEC) | |
148 | break; | |
149 | } | |
150 | read_unlock(&binfmt_lock); | |
151 | } | |
6e8341a1 | 152 | exit: |
1da177e4 LT |
153 | fput(file); |
154 | out: | |
155 | return error; | |
1da177e4 LT |
156 | } |
157 | ||
b6a2fea3 OW |
158 | #ifdef CONFIG_MMU |
159 | ||
160 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
161 | int write) | |
162 | { | |
163 | struct page *page; | |
164 | int ret; | |
165 | ||
166 | #ifdef CONFIG_STACK_GROWSUP | |
167 | if (write) { | |
168 | ret = expand_stack_downwards(bprm->vma, pos); | |
169 | if (ret < 0) | |
170 | return NULL; | |
171 | } | |
172 | #endif | |
173 | ret = get_user_pages(current, bprm->mm, pos, | |
174 | 1, write, 1, &page, NULL); | |
175 | if (ret <= 0) | |
176 | return NULL; | |
177 | ||
178 | if (write) { | |
b6a2fea3 | 179 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
180 | struct rlimit *rlim; |
181 | ||
182 | /* | |
183 | * We've historically supported up to 32 pages (ARG_MAX) | |
184 | * of argument strings even with small stacks | |
185 | */ | |
186 | if (size <= ARG_MAX) | |
187 | return page; | |
b6a2fea3 OW |
188 | |
189 | /* | |
190 | * Limit to 1/4-th the stack size for the argv+env strings. | |
191 | * This ensures that: | |
192 | * - the remaining binfmt code will not run out of stack space, | |
193 | * - the program will have a reasonable amount of stack left | |
194 | * to work from. | |
195 | */ | |
a64e715f | 196 | rlim = current->signal->rlim; |
d554ed89 | 197 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
b6a2fea3 OW |
198 | put_page(page); |
199 | return NULL; | |
200 | } | |
201 | } | |
202 | ||
203 | return page; | |
204 | } | |
205 | ||
206 | static void put_arg_page(struct page *page) | |
207 | { | |
208 | put_page(page); | |
209 | } | |
210 | ||
211 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
212 | { | |
213 | } | |
214 | ||
215 | static void free_arg_pages(struct linux_binprm *bprm) | |
216 | { | |
217 | } | |
218 | ||
219 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
220 | struct page *page) | |
221 | { | |
222 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
223 | } | |
224 | ||
225 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
226 | { | |
eaccbfa5 | 227 | int err; |
b6a2fea3 OW |
228 | struct vm_area_struct *vma = NULL; |
229 | struct mm_struct *mm = bprm->mm; | |
230 | ||
231 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
232 | if (!vma) | |
eaccbfa5 | 233 | return -ENOMEM; |
b6a2fea3 OW |
234 | |
235 | down_write(&mm->mmap_sem); | |
236 | vma->vm_mm = mm; | |
237 | ||
238 | /* | |
239 | * Place the stack at the largest stack address the architecture | |
240 | * supports. Later, we'll move this to an appropriate place. We don't | |
241 | * use STACK_TOP because that can depend on attributes which aren't | |
242 | * configured yet. | |
243 | */ | |
a8bef8ff | 244 | BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
245 | vma->vm_end = STACK_TOP_MAX; |
246 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
a8bef8ff | 247 | vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 248 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
5beb4930 | 249 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
b6a2fea3 | 250 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 251 | if (err) |
b6a2fea3 | 252 | goto err; |
b6a2fea3 OW |
253 | |
254 | mm->stack_vm = mm->total_vm = 1; | |
255 | up_write(&mm->mmap_sem); | |
b6a2fea3 | 256 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 257 | return 0; |
b6a2fea3 | 258 | err: |
eaccbfa5 LFC |
259 | up_write(&mm->mmap_sem); |
260 | bprm->vma = NULL; | |
261 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
262 | return err; |
263 | } | |
264 | ||
265 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
266 | { | |
267 | return len <= MAX_ARG_STRLEN; | |
268 | } | |
269 | ||
270 | #else | |
271 | ||
272 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
273 | int write) | |
274 | { | |
275 | struct page *page; | |
276 | ||
277 | page = bprm->page[pos / PAGE_SIZE]; | |
278 | if (!page && write) { | |
279 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
280 | if (!page) | |
281 | return NULL; | |
282 | bprm->page[pos / PAGE_SIZE] = page; | |
283 | } | |
284 | ||
285 | return page; | |
286 | } | |
287 | ||
288 | static void put_arg_page(struct page *page) | |
289 | { | |
290 | } | |
291 | ||
292 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
293 | { | |
294 | if (bprm->page[i]) { | |
295 | __free_page(bprm->page[i]); | |
296 | bprm->page[i] = NULL; | |
297 | } | |
298 | } | |
299 | ||
300 | static void free_arg_pages(struct linux_binprm *bprm) | |
301 | { | |
302 | int i; | |
303 | ||
304 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
305 | free_arg_page(bprm, i); | |
306 | } | |
307 | ||
308 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
309 | struct page *page) | |
310 | { | |
311 | } | |
312 | ||
313 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
314 | { | |
315 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
316 | return 0; | |
317 | } | |
318 | ||
319 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
320 | { | |
321 | return len <= bprm->p; | |
322 | } | |
323 | ||
324 | #endif /* CONFIG_MMU */ | |
325 | ||
326 | /* | |
327 | * Create a new mm_struct and populate it with a temporary stack | |
328 | * vm_area_struct. We don't have enough context at this point to set the stack | |
329 | * flags, permissions, and offset, so we use temporary values. We'll update | |
330 | * them later in setup_arg_pages(). | |
331 | */ | |
332 | int bprm_mm_init(struct linux_binprm *bprm) | |
333 | { | |
334 | int err; | |
335 | struct mm_struct *mm = NULL; | |
336 | ||
337 | bprm->mm = mm = mm_alloc(); | |
338 | err = -ENOMEM; | |
339 | if (!mm) | |
340 | goto err; | |
341 | ||
342 | err = init_new_context(current, mm); | |
343 | if (err) | |
344 | goto err; | |
345 | ||
346 | err = __bprm_mm_init(bprm); | |
347 | if (err) | |
348 | goto err; | |
349 | ||
350 | return 0; | |
351 | ||
352 | err: | |
353 | if (mm) { | |
354 | bprm->mm = NULL; | |
355 | mmdrop(mm); | |
356 | } | |
357 | ||
358 | return err; | |
359 | } | |
360 | ||
1da177e4 LT |
361 | /* |
362 | * count() counts the number of strings in array ARGV. | |
363 | */ | |
d7627467 | 364 | static int count(const char __user * const __user * argv, int max) |
1da177e4 LT |
365 | { |
366 | int i = 0; | |
367 | ||
368 | if (argv != NULL) { | |
369 | for (;;) { | |
d7627467 | 370 | const char __user * p; |
1da177e4 LT |
371 | |
372 | if (get_user(p, argv)) | |
373 | return -EFAULT; | |
374 | if (!p) | |
375 | break; | |
376 | argv++; | |
362e6663 | 377 | if (i++ >= max) |
1da177e4 | 378 | return -E2BIG; |
9aea5a65 RM |
379 | |
380 | if (fatal_signal_pending(current)) | |
381 | return -ERESTARTNOHAND; | |
1da177e4 LT |
382 | cond_resched(); |
383 | } | |
384 | } | |
385 | return i; | |
386 | } | |
387 | ||
388 | /* | |
b6a2fea3 OW |
389 | * 'copy_strings()' copies argument/environment strings from the old |
390 | * processes's memory to the new process's stack. The call to get_user_pages() | |
391 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 392 | */ |
d7627467 | 393 | static int copy_strings(int argc, const char __user *const __user *argv, |
75c96f85 | 394 | struct linux_binprm *bprm) |
1da177e4 LT |
395 | { |
396 | struct page *kmapped_page = NULL; | |
397 | char *kaddr = NULL; | |
b6a2fea3 | 398 | unsigned long kpos = 0; |
1da177e4 LT |
399 | int ret; |
400 | ||
401 | while (argc-- > 0) { | |
d7627467 | 402 | const char __user *str; |
1da177e4 LT |
403 | int len; |
404 | unsigned long pos; | |
405 | ||
406 | if (get_user(str, argv+argc) || | |
b6a2fea3 | 407 | !(len = strnlen_user(str, MAX_ARG_STRLEN))) { |
1da177e4 LT |
408 | ret = -EFAULT; |
409 | goto out; | |
410 | } | |
411 | ||
b6a2fea3 | 412 | if (!valid_arg_len(bprm, len)) { |
1da177e4 LT |
413 | ret = -E2BIG; |
414 | goto out; | |
415 | } | |
416 | ||
b6a2fea3 | 417 | /* We're going to work our way backwords. */ |
1da177e4 | 418 | pos = bprm->p; |
b6a2fea3 OW |
419 | str += len; |
420 | bprm->p -= len; | |
1da177e4 LT |
421 | |
422 | while (len > 0) { | |
1da177e4 | 423 | int offset, bytes_to_copy; |
1da177e4 | 424 | |
9aea5a65 RM |
425 | if (fatal_signal_pending(current)) { |
426 | ret = -ERESTARTNOHAND; | |
427 | goto out; | |
428 | } | |
7993bc1f RM |
429 | cond_resched(); |
430 | ||
1da177e4 | 431 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
432 | if (offset == 0) |
433 | offset = PAGE_SIZE; | |
434 | ||
435 | bytes_to_copy = offset; | |
436 | if (bytes_to_copy > len) | |
437 | bytes_to_copy = len; | |
438 | ||
439 | offset -= bytes_to_copy; | |
440 | pos -= bytes_to_copy; | |
441 | str -= bytes_to_copy; | |
442 | len -= bytes_to_copy; | |
443 | ||
444 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
445 | struct page *page; | |
446 | ||
447 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 448 | if (!page) { |
b6a2fea3 | 449 | ret = -E2BIG; |
1da177e4 LT |
450 | goto out; |
451 | } | |
1da177e4 | 452 | |
b6a2fea3 OW |
453 | if (kmapped_page) { |
454 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 455 | kunmap(kmapped_page); |
b6a2fea3 OW |
456 | put_arg_page(kmapped_page); |
457 | } | |
1da177e4 LT |
458 | kmapped_page = page; |
459 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
460 | kpos = pos & PAGE_MASK; |
461 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 462 | } |
b6a2fea3 | 463 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
464 | ret = -EFAULT; |
465 | goto out; | |
466 | } | |
1da177e4 LT |
467 | } |
468 | } | |
469 | ret = 0; | |
470 | out: | |
b6a2fea3 OW |
471 | if (kmapped_page) { |
472 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 473 | kunmap(kmapped_page); |
b6a2fea3 OW |
474 | put_arg_page(kmapped_page); |
475 | } | |
1da177e4 LT |
476 | return ret; |
477 | } | |
478 | ||
479 | /* | |
480 | * Like copy_strings, but get argv and its values from kernel memory. | |
481 | */ | |
d7627467 DH |
482 | int copy_strings_kernel(int argc, const char *const *argv, |
483 | struct linux_binprm *bprm) | |
1da177e4 LT |
484 | { |
485 | int r; | |
486 | mm_segment_t oldfs = get_fs(); | |
487 | set_fs(KERNEL_DS); | |
d7627467 | 488 | r = copy_strings(argc, (const char __user *const __user *)argv, bprm); |
1da177e4 LT |
489 | set_fs(oldfs); |
490 | return r; | |
491 | } | |
1da177e4 LT |
492 | EXPORT_SYMBOL(copy_strings_kernel); |
493 | ||
494 | #ifdef CONFIG_MMU | |
b6a2fea3 | 495 | |
1da177e4 | 496 | /* |
b6a2fea3 OW |
497 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
498 | * the binfmt code determines where the new stack should reside, we shift it to | |
499 | * its final location. The process proceeds as follows: | |
1da177e4 | 500 | * |
b6a2fea3 OW |
501 | * 1) Use shift to calculate the new vma endpoints. |
502 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
503 | * arguments passed to subsequent functions are consistent. | |
504 | * 3) Move vma's page tables to the new range. | |
505 | * 4) Free up any cleared pgd range. | |
506 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 507 | */ |
b6a2fea3 | 508 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
509 | { |
510 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
511 | unsigned long old_start = vma->vm_start; |
512 | unsigned long old_end = vma->vm_end; | |
513 | unsigned long length = old_end - old_start; | |
514 | unsigned long new_start = old_start - shift; | |
515 | unsigned long new_end = old_end - shift; | |
516 | struct mmu_gather *tlb; | |
1da177e4 | 517 | |
b6a2fea3 | 518 | BUG_ON(new_start > new_end); |
1da177e4 | 519 | |
b6a2fea3 OW |
520 | /* |
521 | * ensure there are no vmas between where we want to go | |
522 | * and where we are | |
523 | */ | |
524 | if (vma != find_vma(mm, new_start)) | |
525 | return -EFAULT; | |
526 | ||
527 | /* | |
528 | * cover the whole range: [new_start, old_end) | |
529 | */ | |
5beb4930 RR |
530 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
531 | return -ENOMEM; | |
b6a2fea3 OW |
532 | |
533 | /* | |
534 | * move the page tables downwards, on failure we rely on | |
535 | * process cleanup to remove whatever mess we made. | |
536 | */ | |
537 | if (length != move_page_tables(vma, old_start, | |
538 | vma, new_start, length)) | |
539 | return -ENOMEM; | |
540 | ||
541 | lru_add_drain(); | |
542 | tlb = tlb_gather_mmu(mm, 0); | |
543 | if (new_end > old_start) { | |
544 | /* | |
545 | * when the old and new regions overlap clear from new_end. | |
546 | */ | |
42b77728 | 547 | free_pgd_range(tlb, new_end, old_end, new_end, |
b6a2fea3 OW |
548 | vma->vm_next ? vma->vm_next->vm_start : 0); |
549 | } else { | |
550 | /* | |
551 | * otherwise, clean from old_start; this is done to not touch | |
552 | * the address space in [new_end, old_start) some architectures | |
553 | * have constraints on va-space that make this illegal (IA64) - | |
554 | * for the others its just a little faster. | |
555 | */ | |
42b77728 | 556 | free_pgd_range(tlb, old_start, old_end, new_end, |
b6a2fea3 | 557 | vma->vm_next ? vma->vm_next->vm_start : 0); |
1da177e4 | 558 | } |
b6a2fea3 OW |
559 | tlb_finish_mmu(tlb, new_end, old_end); |
560 | ||
561 | /* | |
5beb4930 | 562 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
563 | */ |
564 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
565 | ||
566 | return 0; | |
1da177e4 LT |
567 | } |
568 | ||
b6a2fea3 OW |
569 | /* |
570 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
571 | * the stack is optionally relocated, and some extra space is added. | |
572 | */ | |
1da177e4 LT |
573 | int setup_arg_pages(struct linux_binprm *bprm, |
574 | unsigned long stack_top, | |
575 | int executable_stack) | |
576 | { | |
b6a2fea3 OW |
577 | unsigned long ret; |
578 | unsigned long stack_shift; | |
1da177e4 | 579 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
580 | struct vm_area_struct *vma = bprm->vma; |
581 | struct vm_area_struct *prev = NULL; | |
582 | unsigned long vm_flags; | |
583 | unsigned long stack_base; | |
803bf5ec MN |
584 | unsigned long stack_size; |
585 | unsigned long stack_expand; | |
586 | unsigned long rlim_stack; | |
1da177e4 LT |
587 | |
588 | #ifdef CONFIG_STACK_GROWSUP | |
1da177e4 | 589 | /* Limit stack size to 1GB */ |
d554ed89 | 590 | stack_base = rlimit_max(RLIMIT_STACK); |
1da177e4 LT |
591 | if (stack_base > (1 << 30)) |
592 | stack_base = 1 << 30; | |
1da177e4 | 593 | |
b6a2fea3 OW |
594 | /* Make sure we didn't let the argument array grow too large. */ |
595 | if (vma->vm_end - vma->vm_start > stack_base) | |
596 | return -ENOMEM; | |
1da177e4 | 597 | |
b6a2fea3 | 598 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 599 | |
b6a2fea3 OW |
600 | stack_shift = vma->vm_start - stack_base; |
601 | mm->arg_start = bprm->p - stack_shift; | |
602 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 603 | #else |
b6a2fea3 OW |
604 | stack_top = arch_align_stack(stack_top); |
605 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
606 | |
607 | if (unlikely(stack_top < mmap_min_addr) || | |
608 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
609 | return -ENOMEM; | |
610 | ||
b6a2fea3 OW |
611 | stack_shift = vma->vm_end - stack_top; |
612 | ||
613 | bprm->p -= stack_shift; | |
1da177e4 | 614 | mm->arg_start = bprm->p; |
1da177e4 LT |
615 | #endif |
616 | ||
1da177e4 | 617 | if (bprm->loader) |
b6a2fea3 OW |
618 | bprm->loader -= stack_shift; |
619 | bprm->exec -= stack_shift; | |
1da177e4 | 620 | |
1da177e4 | 621 | down_write(&mm->mmap_sem); |
96a8e13e | 622 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
623 | |
624 | /* | |
625 | * Adjust stack execute permissions; explicitly enable for | |
626 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
627 | * (arch default) otherwise. | |
628 | */ | |
629 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
630 | vm_flags |= VM_EXEC; | |
631 | else if (executable_stack == EXSTACK_DISABLE_X) | |
632 | vm_flags &= ~VM_EXEC; | |
633 | vm_flags |= mm->def_flags; | |
a8bef8ff | 634 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
635 | |
636 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
637 | vm_flags); | |
638 | if (ret) | |
639 | goto out_unlock; | |
640 | BUG_ON(prev != vma); | |
641 | ||
642 | /* Move stack pages down in memory. */ | |
643 | if (stack_shift) { | |
644 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
645 | if (ret) |
646 | goto out_unlock; | |
1da177e4 LT |
647 | } |
648 | ||
a8bef8ff MG |
649 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
650 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
651 | ||
5ef097dd | 652 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
653 | stack_size = vma->vm_end - vma->vm_start; |
654 | /* | |
655 | * Align this down to a page boundary as expand_stack | |
656 | * will align it up. | |
657 | */ | |
658 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
b6a2fea3 | 659 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
660 | if (stack_size + stack_expand > rlim_stack) |
661 | stack_base = vma->vm_start + rlim_stack; | |
662 | else | |
663 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 664 | #else |
803bf5ec MN |
665 | if (stack_size + stack_expand > rlim_stack) |
666 | stack_base = vma->vm_end - rlim_stack; | |
667 | else | |
668 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 669 | #endif |
3af9e859 | 670 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
671 | ret = expand_stack(vma, stack_base); |
672 | if (ret) | |
673 | ret = -EFAULT; | |
674 | ||
675 | out_unlock: | |
1da177e4 | 676 | up_write(&mm->mmap_sem); |
fc63cf23 | 677 | return ret; |
1da177e4 | 678 | } |
1da177e4 LT |
679 | EXPORT_SYMBOL(setup_arg_pages); |
680 | ||
1da177e4 LT |
681 | #endif /* CONFIG_MMU */ |
682 | ||
683 | struct file *open_exec(const char *name) | |
684 | { | |
1da177e4 | 685 | struct file *file; |
e56b6a5d | 686 | int err; |
1da177e4 | 687 | |
6e8341a1 AV |
688 | file = do_filp_open(AT_FDCWD, name, |
689 | O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0, | |
690 | MAY_EXEC | MAY_OPEN); | |
691 | if (IS_ERR(file)) | |
e56b6a5d CH |
692 | goto out; |
693 | ||
694 | err = -EACCES; | |
6e8341a1 AV |
695 | if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
696 | goto exit; | |
e56b6a5d | 697 | |
6e8341a1 AV |
698 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
699 | goto exit; | |
e56b6a5d | 700 | |
2a12a9d7 | 701 | fsnotify_open(file); |
6110e3ab | 702 | |
e56b6a5d | 703 | err = deny_write_access(file); |
6e8341a1 AV |
704 | if (err) |
705 | goto exit; | |
1da177e4 | 706 | |
6e8341a1 | 707 | out: |
e56b6a5d CH |
708 | return file; |
709 | ||
6e8341a1 AV |
710 | exit: |
711 | fput(file); | |
e56b6a5d CH |
712 | return ERR_PTR(err); |
713 | } | |
1da177e4 LT |
714 | EXPORT_SYMBOL(open_exec); |
715 | ||
6777d773 MZ |
716 | int kernel_read(struct file *file, loff_t offset, |
717 | char *addr, unsigned long count) | |
1da177e4 LT |
718 | { |
719 | mm_segment_t old_fs; | |
720 | loff_t pos = offset; | |
721 | int result; | |
722 | ||
723 | old_fs = get_fs(); | |
724 | set_fs(get_ds()); | |
725 | /* The cast to a user pointer is valid due to the set_fs() */ | |
726 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
727 | set_fs(old_fs); | |
728 | return result; | |
729 | } | |
730 | ||
731 | EXPORT_SYMBOL(kernel_read); | |
732 | ||
733 | static int exec_mmap(struct mm_struct *mm) | |
734 | { | |
735 | struct task_struct *tsk; | |
736 | struct mm_struct * old_mm, *active_mm; | |
737 | ||
738 | /* Notify parent that we're no longer interested in the old VM */ | |
739 | tsk = current; | |
740 | old_mm = current->mm; | |
34e55232 | 741 | sync_mm_rss(tsk, old_mm); |
1da177e4 LT |
742 | mm_release(tsk, old_mm); |
743 | ||
744 | if (old_mm) { | |
745 | /* | |
746 | * Make sure that if there is a core dump in progress | |
747 | * for the old mm, we get out and die instead of going | |
748 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 749 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
750 | */ |
751 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 752 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
753 | up_read(&old_mm->mmap_sem); |
754 | return -EINTR; | |
755 | } | |
756 | } | |
757 | task_lock(tsk); | |
758 | active_mm = tsk->active_mm; | |
759 | tsk->mm = mm; | |
760 | tsk->active_mm = mm; | |
761 | activate_mm(active_mm, mm); | |
762 | task_unlock(tsk); | |
763 | arch_pick_mmap_layout(mm); | |
764 | if (old_mm) { | |
765 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 766 | BUG_ON(active_mm != old_mm); |
31a78f23 | 767 | mm_update_next_owner(old_mm); |
1da177e4 LT |
768 | mmput(old_mm); |
769 | return 0; | |
770 | } | |
771 | mmdrop(active_mm); | |
772 | return 0; | |
773 | } | |
774 | ||
775 | /* | |
776 | * This function makes sure the current process has its own signal table, | |
777 | * so that flush_signal_handlers can later reset the handlers without | |
778 | * disturbing other processes. (Other processes might share the signal | |
779 | * table via the CLONE_SIGHAND option to clone().) | |
780 | */ | |
858119e1 | 781 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
782 | { |
783 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 784 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 785 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 786 | |
aafe6c2a | 787 | if (thread_group_empty(tsk)) |
1da177e4 LT |
788 | goto no_thread_group; |
789 | ||
790 | /* | |
791 | * Kill all other threads in the thread group. | |
1da177e4 | 792 | */ |
1da177e4 | 793 | spin_lock_irq(lock); |
ed5d2cac | 794 | if (signal_group_exit(sig)) { |
1da177e4 LT |
795 | /* |
796 | * Another group action in progress, just | |
797 | * return so that the signal is processed. | |
798 | */ | |
799 | spin_unlock_irq(lock); | |
1da177e4 LT |
800 | return -EAGAIN; |
801 | } | |
d344193a | 802 | |
ed5d2cac | 803 | sig->group_exit_task = tsk; |
d344193a ON |
804 | sig->notify_count = zap_other_threads(tsk); |
805 | if (!thread_group_leader(tsk)) | |
806 | sig->notify_count--; | |
1da177e4 | 807 | |
d344193a | 808 | while (sig->notify_count) { |
1da177e4 LT |
809 | __set_current_state(TASK_UNINTERRUPTIBLE); |
810 | spin_unlock_irq(lock); | |
811 | schedule(); | |
812 | spin_lock_irq(lock); | |
813 | } | |
1da177e4 LT |
814 | spin_unlock_irq(lock); |
815 | ||
816 | /* | |
817 | * At this point all other threads have exited, all we have to | |
818 | * do is to wait for the thread group leader to become inactive, | |
819 | * and to assume its PID: | |
820 | */ | |
aafe6c2a | 821 | if (!thread_group_leader(tsk)) { |
8187926b | 822 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 823 | |
2800d8d1 | 824 | sig->notify_count = -1; /* for exit_notify() */ |
6db840fa ON |
825 | for (;;) { |
826 | write_lock_irq(&tasklist_lock); | |
827 | if (likely(leader->exit_state)) | |
828 | break; | |
829 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
830 | write_unlock_irq(&tasklist_lock); | |
831 | schedule(); | |
832 | } | |
1da177e4 | 833 | |
f5e90281 RM |
834 | /* |
835 | * The only record we have of the real-time age of a | |
836 | * process, regardless of execs it's done, is start_time. | |
837 | * All the past CPU time is accumulated in signal_struct | |
838 | * from sister threads now dead. But in this non-leader | |
839 | * exec, nothing survives from the original leader thread, | |
840 | * whose birth marks the true age of this process now. | |
841 | * When we take on its identity by switching to its PID, we | |
842 | * also take its birthdate (always earlier than our own). | |
843 | */ | |
aafe6c2a | 844 | tsk->start_time = leader->start_time; |
f5e90281 | 845 | |
bac0abd6 PE |
846 | BUG_ON(!same_thread_group(leader, tsk)); |
847 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
848 | /* |
849 | * An exec() starts a new thread group with the | |
850 | * TGID of the previous thread group. Rehash the | |
851 | * two threads with a switched PID, and release | |
852 | * the former thread group leader: | |
853 | */ | |
d73d6529 EB |
854 | |
855 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
856 | * The old leader becomes a thread of the this thread group. |
857 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
858 | * is called. Odd but simple and correct. |
859 | */ | |
aafe6c2a EB |
860 | detach_pid(tsk, PIDTYPE_PID); |
861 | tsk->pid = leader->pid; | |
3743ca05 | 862 | attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
863 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
864 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 865 | |
aafe6c2a | 866 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 867 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 868 | |
aafe6c2a EB |
869 | tsk->group_leader = tsk; |
870 | leader->group_leader = tsk; | |
de12a787 | 871 | |
aafe6c2a | 872 | tsk->exit_signal = SIGCHLD; |
962b564c ON |
873 | |
874 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
875 | leader->exit_state = EXIT_DEAD; | |
1da177e4 | 876 | write_unlock_irq(&tasklist_lock); |
8187926b ON |
877 | |
878 | release_task(leader); | |
ed5d2cac | 879 | } |
1da177e4 | 880 | |
6db840fa ON |
881 | sig->group_exit_task = NULL; |
882 | sig->notify_count = 0; | |
1da177e4 LT |
883 | |
884 | no_thread_group: | |
1f10206c JP |
885 | if (current->mm) |
886 | setmax_mm_hiwater_rss(&sig->maxrss, current->mm); | |
887 | ||
1da177e4 | 888 | exit_itimers(sig); |
cbaffba1 | 889 | flush_itimer_signals(); |
329f7dba | 890 | |
b2c903b8 ON |
891 | if (atomic_read(&oldsighand->count) != 1) { |
892 | struct sighand_struct *newsighand; | |
1da177e4 | 893 | /* |
b2c903b8 ON |
894 | * This ->sighand is shared with the CLONE_SIGHAND |
895 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 896 | */ |
b2c903b8 ON |
897 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
898 | if (!newsighand) | |
899 | return -ENOMEM; | |
900 | ||
1da177e4 LT |
901 | atomic_set(&newsighand->count, 1); |
902 | memcpy(newsighand->action, oldsighand->action, | |
903 | sizeof(newsighand->action)); | |
904 | ||
905 | write_lock_irq(&tasklist_lock); | |
906 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 907 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
908 | spin_unlock(&oldsighand->siglock); |
909 | write_unlock_irq(&tasklist_lock); | |
910 | ||
fba2afaa | 911 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
912 | } |
913 | ||
aafe6c2a | 914 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 LT |
915 | return 0; |
916 | } | |
0840a90d | 917 | |
1da177e4 LT |
918 | /* |
919 | * These functions flushes out all traces of the currently running executable | |
920 | * so that a new one can be started | |
921 | */ | |
858119e1 | 922 | static void flush_old_files(struct files_struct * files) |
1da177e4 LT |
923 | { |
924 | long j = -1; | |
badf1662 | 925 | struct fdtable *fdt; |
1da177e4 LT |
926 | |
927 | spin_lock(&files->file_lock); | |
928 | for (;;) { | |
929 | unsigned long set, i; | |
930 | ||
931 | j++; | |
932 | i = j * __NFDBITS; | |
badf1662 | 933 | fdt = files_fdtable(files); |
bbea9f69 | 934 | if (i >= fdt->max_fds) |
1da177e4 | 935 | break; |
badf1662 | 936 | set = fdt->close_on_exec->fds_bits[j]; |
1da177e4 LT |
937 | if (!set) |
938 | continue; | |
badf1662 | 939 | fdt->close_on_exec->fds_bits[j] = 0; |
1da177e4 LT |
940 | spin_unlock(&files->file_lock); |
941 | for ( ; set ; i++,set >>= 1) { | |
942 | if (set & 1) { | |
943 | sys_close(i); | |
944 | } | |
945 | } | |
946 | spin_lock(&files->file_lock); | |
947 | ||
948 | } | |
949 | spin_unlock(&files->file_lock); | |
950 | } | |
951 | ||
59714d65 | 952 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
953 | { |
954 | /* buf must be at least sizeof(tsk->comm) in size */ | |
955 | task_lock(tsk); | |
956 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
957 | task_unlock(tsk); | |
59714d65 | 958 | return buf; |
1da177e4 LT |
959 | } |
960 | ||
961 | void set_task_comm(struct task_struct *tsk, char *buf) | |
962 | { | |
963 | task_lock(tsk); | |
4614a696 | 964 | |
965 | /* | |
966 | * Threads may access current->comm without holding | |
967 | * the task lock, so write the string carefully. | |
968 | * Readers without a lock may see incomplete new | |
969 | * names but are safe from non-terminating string reads. | |
970 | */ | |
971 | memset(tsk->comm, 0, TASK_COMM_LEN); | |
972 | wmb(); | |
1da177e4 LT |
973 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
974 | task_unlock(tsk); | |
cdd6c482 | 975 | perf_event_comm(tsk); |
1da177e4 LT |
976 | } |
977 | ||
978 | int flush_old_exec(struct linux_binprm * bprm) | |
979 | { | |
221af7f8 | 980 | int retval; |
1da177e4 LT |
981 | |
982 | /* | |
983 | * Make sure we have a private signal table and that | |
984 | * we are unassociated from the previous thread group. | |
985 | */ | |
986 | retval = de_thread(current); | |
987 | if (retval) | |
988 | goto out; | |
989 | ||
925d1c40 MH |
990 | set_mm_exe_file(bprm->mm, bprm->file); |
991 | ||
1da177e4 LT |
992 | /* |
993 | * Release all of the old mmap stuff | |
994 | */ | |
995 | retval = exec_mmap(bprm->mm); | |
996 | if (retval) | |
fd8328be | 997 | goto out; |
1da177e4 LT |
998 | |
999 | bprm->mm = NULL; /* We're using it now */ | |
7ab02af4 LT |
1000 | |
1001 | current->flags &= ~PF_RANDOMIZE; | |
1002 | flush_thread(); | |
1003 | current->personality &= ~bprm->per_clear; | |
1004 | ||
221af7f8 LT |
1005 | return 0; |
1006 | ||
1007 | out: | |
1008 | return retval; | |
1009 | } | |
1010 | EXPORT_SYMBOL(flush_old_exec); | |
1011 | ||
1012 | void setup_new_exec(struct linux_binprm * bprm) | |
1013 | { | |
1014 | int i, ch; | |
d7627467 | 1015 | const char *name; |
221af7f8 LT |
1016 | char tcomm[sizeof(current->comm)]; |
1017 | ||
1018 | arch_pick_mmap_layout(current->mm); | |
1da177e4 LT |
1019 | |
1020 | /* This is the point of no return */ | |
1da177e4 LT |
1021 | current->sas_ss_sp = current->sas_ss_size = 0; |
1022 | ||
da9592ed | 1023 | if (current_euid() == current_uid() && current_egid() == current_gid()) |
6c5d5238 | 1024 | set_dumpable(current->mm, 1); |
d6e71144 | 1025 | else |
6c5d5238 | 1026 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1027 | |
1da177e4 | 1028 | name = bprm->filename; |
36772092 PBG |
1029 | |
1030 | /* Copies the binary name from after last slash */ | |
1da177e4 LT |
1031 | for (i=0; (ch = *(name++)) != '\0';) { |
1032 | if (ch == '/') | |
36772092 | 1033 | i = 0; /* overwrite what we wrote */ |
1da177e4 LT |
1034 | else |
1035 | if (i < (sizeof(tcomm) - 1)) | |
1036 | tcomm[i++] = ch; | |
1037 | } | |
1038 | tcomm[i] = '\0'; | |
1039 | set_task_comm(current, tcomm); | |
1040 | ||
0551fbd2 BH |
1041 | /* Set the new mm task size. We have to do that late because it may |
1042 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1043 | * some architectures like powerpc | |
1044 | */ | |
1045 | current->mm->task_size = TASK_SIZE; | |
1046 | ||
a6f76f23 DH |
1047 | /* install the new credentials */ |
1048 | if (bprm->cred->uid != current_euid() || | |
1049 | bprm->cred->gid != current_egid()) { | |
d2d56c5f MH |
1050 | current->pdeath_signal = 0; |
1051 | } else if (file_permission(bprm->file, MAY_READ) || | |
a6f76f23 | 1052 | bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) { |
6c5d5238 | 1053 | set_dumpable(current->mm, suid_dumpable); |
1da177e4 LT |
1054 | } |
1055 | ||
f65cb45c IM |
1056 | /* |
1057 | * Flush performance counters when crossing a | |
1058 | * security domain: | |
1059 | */ | |
1060 | if (!get_dumpable(current->mm)) | |
cdd6c482 | 1061 | perf_event_exit_task(current); |
f65cb45c | 1062 | |
1da177e4 LT |
1063 | /* An exec changes our domain. We are no longer part of the thread |
1064 | group */ | |
1065 | ||
1066 | current->self_exec_id++; | |
1067 | ||
1068 | flush_signal_handlers(current, 0); | |
1069 | flush_old_files(current->files); | |
1da177e4 | 1070 | } |
221af7f8 | 1071 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1072 | |
a2a8474c ON |
1073 | /* |
1074 | * Prepare credentials and lock ->cred_guard_mutex. | |
1075 | * install_exec_creds() commits the new creds and drops the lock. | |
1076 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1077 | * and unlock. | |
1078 | */ | |
1079 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1080 | { | |
1081 | if (mutex_lock_interruptible(¤t->cred_guard_mutex)) | |
1082 | return -ERESTARTNOINTR; | |
1083 | ||
1084 | bprm->cred = prepare_exec_creds(); | |
1085 | if (likely(bprm->cred)) | |
1086 | return 0; | |
1087 | ||
1088 | mutex_unlock(¤t->cred_guard_mutex); | |
1089 | return -ENOMEM; | |
1090 | } | |
1091 | ||
1092 | void free_bprm(struct linux_binprm *bprm) | |
1093 | { | |
1094 | free_arg_pages(bprm); | |
1095 | if (bprm->cred) { | |
1096 | mutex_unlock(¤t->cred_guard_mutex); | |
1097 | abort_creds(bprm->cred); | |
1098 | } | |
1099 | kfree(bprm); | |
1100 | } | |
1101 | ||
a6f76f23 DH |
1102 | /* |
1103 | * install the new credentials for this executable | |
1104 | */ | |
1105 | void install_exec_creds(struct linux_binprm *bprm) | |
1106 | { | |
1107 | security_bprm_committing_creds(bprm); | |
1108 | ||
1109 | commit_creds(bprm->cred); | |
1110 | bprm->cred = NULL; | |
a2a8474c ON |
1111 | /* |
1112 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1113 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1114 | * credentials; any time after this it may be unlocked. |
1115 | */ | |
a6f76f23 | 1116 | security_bprm_committed_creds(bprm); |
a2a8474c | 1117 | mutex_unlock(¤t->cred_guard_mutex); |
a6f76f23 DH |
1118 | } |
1119 | EXPORT_SYMBOL(install_exec_creds); | |
1120 | ||
1121 | /* | |
1122 | * determine how safe it is to execute the proposed program | |
5e751e99 | 1123 | * - the caller must hold current->cred_guard_mutex to protect against |
a6f76f23 DH |
1124 | * PTRACE_ATTACH |
1125 | */ | |
498052bb | 1126 | int check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1127 | { |
0bf2f3ae | 1128 | struct task_struct *p = current, *t; |
f1191b50 | 1129 | unsigned n_fs; |
498052bb | 1130 | int res = 0; |
a6f76f23 DH |
1131 | |
1132 | bprm->unsafe = tracehook_unsafe_exec(p); | |
1133 | ||
0bf2f3ae | 1134 | n_fs = 1; |
2a4419b5 | 1135 | spin_lock(&p->fs->lock); |
437f7fdb | 1136 | rcu_read_lock(); |
0bf2f3ae DH |
1137 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
1138 | if (t->fs == p->fs) | |
1139 | n_fs++; | |
0bf2f3ae | 1140 | } |
437f7fdb | 1141 | rcu_read_unlock(); |
0bf2f3ae | 1142 | |
f1191b50 | 1143 | if (p->fs->users > n_fs) { |
a6f76f23 | 1144 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
498052bb | 1145 | } else { |
8c652f96 ON |
1146 | res = -EAGAIN; |
1147 | if (!p->fs->in_exec) { | |
1148 | p->fs->in_exec = 1; | |
1149 | res = 1; | |
1150 | } | |
498052bb | 1151 | } |
2a4419b5 | 1152 | spin_unlock(&p->fs->lock); |
498052bb AV |
1153 | |
1154 | return res; | |
a6f76f23 DH |
1155 | } |
1156 | ||
1da177e4 LT |
1157 | /* |
1158 | * Fill the binprm structure from the inode. | |
1159 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes | |
a6f76f23 DH |
1160 | * |
1161 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1162 | */ |
1163 | int prepare_binprm(struct linux_binprm *bprm) | |
1164 | { | |
a6f76f23 | 1165 | umode_t mode; |
0f7fc9e4 | 1166 | struct inode * inode = bprm->file->f_path.dentry->d_inode; |
1da177e4 LT |
1167 | int retval; |
1168 | ||
1169 | mode = inode->i_mode; | |
1da177e4 LT |
1170 | if (bprm->file->f_op == NULL) |
1171 | return -EACCES; | |
1172 | ||
a6f76f23 DH |
1173 | /* clear any previous set[ug]id data from a previous binary */ |
1174 | bprm->cred->euid = current_euid(); | |
1175 | bprm->cred->egid = current_egid(); | |
1da177e4 | 1176 | |
a6f76f23 | 1177 | if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { |
1da177e4 LT |
1178 | /* Set-uid? */ |
1179 | if (mode & S_ISUID) { | |
a6f76f23 DH |
1180 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1181 | bprm->cred->euid = inode->i_uid; | |
1da177e4 LT |
1182 | } |
1183 | ||
1184 | /* Set-gid? */ | |
1185 | /* | |
1186 | * If setgid is set but no group execute bit then this | |
1187 | * is a candidate for mandatory locking, not a setgid | |
1188 | * executable. | |
1189 | */ | |
1190 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
a6f76f23 DH |
1191 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
1192 | bprm->cred->egid = inode->i_gid; | |
1da177e4 LT |
1193 | } |
1194 | } | |
1195 | ||
1196 | /* fill in binprm security blob */ | |
a6f76f23 | 1197 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1198 | if (retval) |
1199 | return retval; | |
a6f76f23 | 1200 | bprm->cred_prepared = 1; |
1da177e4 | 1201 | |
a6f76f23 DH |
1202 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1203 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1204 | } |
1205 | ||
1206 | EXPORT_SYMBOL(prepare_binprm); | |
1207 | ||
4fc75ff4 NP |
1208 | /* |
1209 | * Arguments are '\0' separated strings found at the location bprm->p | |
1210 | * points to; chop off the first by relocating brpm->p to right after | |
1211 | * the first '\0' encountered. | |
1212 | */ | |
b6a2fea3 | 1213 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1214 | { |
b6a2fea3 OW |
1215 | int ret = 0; |
1216 | unsigned long offset; | |
1217 | char *kaddr; | |
1218 | struct page *page; | |
4fc75ff4 | 1219 | |
b6a2fea3 OW |
1220 | if (!bprm->argc) |
1221 | return 0; | |
1da177e4 | 1222 | |
b6a2fea3 OW |
1223 | do { |
1224 | offset = bprm->p & ~PAGE_MASK; | |
1225 | page = get_arg_page(bprm, bprm->p, 0); | |
1226 | if (!page) { | |
1227 | ret = -EFAULT; | |
1228 | goto out; | |
1229 | } | |
1230 | kaddr = kmap_atomic(page, KM_USER0); | |
4fc75ff4 | 1231 | |
b6a2fea3 OW |
1232 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1233 | offset++, bprm->p++) | |
1234 | ; | |
4fc75ff4 | 1235 | |
b6a2fea3 OW |
1236 | kunmap_atomic(kaddr, KM_USER0); |
1237 | put_arg_page(page); | |
4fc75ff4 | 1238 | |
b6a2fea3 OW |
1239 | if (offset == PAGE_SIZE) |
1240 | free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); | |
1241 | } while (offset == PAGE_SIZE); | |
4fc75ff4 | 1242 | |
b6a2fea3 OW |
1243 | bprm->p++; |
1244 | bprm->argc--; | |
1245 | ret = 0; | |
4fc75ff4 | 1246 | |
b6a2fea3 OW |
1247 | out: |
1248 | return ret; | |
1da177e4 | 1249 | } |
1da177e4 LT |
1250 | EXPORT_SYMBOL(remove_arg_zero); |
1251 | ||
1252 | /* | |
1253 | * cycle the list of binary formats handler, until one recognizes the image | |
1254 | */ | |
1255 | int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) | |
1256 | { | |
85f33466 | 1257 | unsigned int depth = bprm->recursion_depth; |
1da177e4 LT |
1258 | int try,retval; |
1259 | struct linux_binfmt *fmt; | |
1da177e4 | 1260 | |
1da177e4 LT |
1261 | retval = security_bprm_check(bprm); |
1262 | if (retval) | |
1263 | return retval; | |
1264 | ||
1265 | /* kernel module loader fixup */ | |
1266 | /* so we don't try to load run modprobe in kernel space. */ | |
1267 | set_fs(USER_DS); | |
473ae30b AV |
1268 | |
1269 | retval = audit_bprm(bprm); | |
1270 | if (retval) | |
1271 | return retval; | |
1272 | ||
1da177e4 LT |
1273 | retval = -ENOENT; |
1274 | for (try=0; try<2; try++) { | |
1275 | read_lock(&binfmt_lock); | |
e4dc1b14 | 1276 | list_for_each_entry(fmt, &formats, lh) { |
1da177e4 LT |
1277 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
1278 | if (!fn) | |
1279 | continue; | |
1280 | if (!try_module_get(fmt->module)) | |
1281 | continue; | |
1282 | read_unlock(&binfmt_lock); | |
1283 | retval = fn(bprm, regs); | |
85f33466 RM |
1284 | /* |
1285 | * Restore the depth counter to its starting value | |
1286 | * in this call, so we don't have to rely on every | |
1287 | * load_binary function to restore it on return. | |
1288 | */ | |
1289 | bprm->recursion_depth = depth; | |
1da177e4 | 1290 | if (retval >= 0) { |
85f33466 RM |
1291 | if (depth == 0) |
1292 | tracehook_report_exec(fmt, bprm, regs); | |
1da177e4 LT |
1293 | put_binfmt(fmt); |
1294 | allow_write_access(bprm->file); | |
1295 | if (bprm->file) | |
1296 | fput(bprm->file); | |
1297 | bprm->file = NULL; | |
1298 | current->did_exec = 1; | |
9f46080c | 1299 | proc_exec_connector(current); |
1da177e4 LT |
1300 | return retval; |
1301 | } | |
1302 | read_lock(&binfmt_lock); | |
1303 | put_binfmt(fmt); | |
1304 | if (retval != -ENOEXEC || bprm->mm == NULL) | |
1305 | break; | |
1306 | if (!bprm->file) { | |
1307 | read_unlock(&binfmt_lock); | |
1308 | return retval; | |
1309 | } | |
1310 | } | |
1311 | read_unlock(&binfmt_lock); | |
1312 | if (retval != -ENOEXEC || bprm->mm == NULL) { | |
1313 | break; | |
5f4123be JB |
1314 | #ifdef CONFIG_MODULES |
1315 | } else { | |
1da177e4 LT |
1316 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1317 | if (printable(bprm->buf[0]) && | |
1318 | printable(bprm->buf[1]) && | |
1319 | printable(bprm->buf[2]) && | |
1320 | printable(bprm->buf[3])) | |
1321 | break; /* -ENOEXEC */ | |
1322 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); | |
1323 | #endif | |
1324 | } | |
1325 | } | |
1326 | return retval; | |
1327 | } | |
1328 | ||
1329 | EXPORT_SYMBOL(search_binary_handler); | |
1330 | ||
1331 | /* | |
1332 | * sys_execve() executes a new program. | |
1333 | */ | |
d7627467 DH |
1334 | int do_execve(const char * filename, |
1335 | const char __user *const __user *argv, | |
1336 | const char __user *const __user *envp, | |
1da177e4 LT |
1337 | struct pt_regs * regs) |
1338 | { | |
1339 | struct linux_binprm *bprm; | |
1340 | struct file *file; | |
3b125388 | 1341 | struct files_struct *displaced; |
8c652f96 | 1342 | bool clear_in_exec; |
1da177e4 | 1343 | int retval; |
1da177e4 | 1344 | |
3b125388 | 1345 | retval = unshare_files(&displaced); |
fd8328be AV |
1346 | if (retval) |
1347 | goto out_ret; | |
1348 | ||
1da177e4 | 1349 | retval = -ENOMEM; |
11b0b5ab | 1350 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1351 | if (!bprm) |
fd8328be | 1352 | goto out_files; |
1da177e4 | 1353 | |
a2a8474c ON |
1354 | retval = prepare_bprm_creds(bprm); |
1355 | if (retval) | |
a6f76f23 | 1356 | goto out_free; |
498052bb AV |
1357 | |
1358 | retval = check_unsafe_exec(bprm); | |
8c652f96 | 1359 | if (retval < 0) |
a2a8474c | 1360 | goto out_free; |
8c652f96 | 1361 | clear_in_exec = retval; |
a2a8474c | 1362 | current->in_execve = 1; |
a6f76f23 | 1363 | |
1da177e4 LT |
1364 | file = open_exec(filename); |
1365 | retval = PTR_ERR(file); | |
1366 | if (IS_ERR(file)) | |
498052bb | 1367 | goto out_unmark; |
1da177e4 LT |
1368 | |
1369 | sched_exec(); | |
1370 | ||
1da177e4 LT |
1371 | bprm->file = file; |
1372 | bprm->filename = filename; | |
1373 | bprm->interp = filename; | |
1da177e4 | 1374 | |
b6a2fea3 OW |
1375 | retval = bprm_mm_init(bprm); |
1376 | if (retval) | |
1377 | goto out_file; | |
1da177e4 | 1378 | |
b6a2fea3 | 1379 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1380 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1381 | goto out; |
1da177e4 | 1382 | |
b6a2fea3 | 1383 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1384 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1385 | goto out; |
1386 | ||
1387 | retval = prepare_binprm(bprm); | |
1388 | if (retval < 0) | |
1389 | goto out; | |
1390 | ||
1391 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1392 | if (retval < 0) | |
1393 | goto out; | |
1394 | ||
1395 | bprm->exec = bprm->p; | |
1396 | retval = copy_strings(bprm->envc, envp, bprm); | |
1397 | if (retval < 0) | |
1398 | goto out; | |
1399 | ||
1400 | retval = copy_strings(bprm->argc, argv, bprm); | |
1401 | if (retval < 0) | |
1402 | goto out; | |
1403 | ||
7b34e428 | 1404 | current->flags &= ~PF_KTHREAD; |
1da177e4 | 1405 | retval = search_binary_handler(bprm,regs); |
a6f76f23 DH |
1406 | if (retval < 0) |
1407 | goto out; | |
1da177e4 | 1408 | |
a6f76f23 | 1409 | /* execve succeeded */ |
498052bb | 1410 | current->fs->in_exec = 0; |
f9ce1f1c | 1411 | current->in_execve = 0; |
a6f76f23 DH |
1412 | acct_update_integrals(current); |
1413 | free_bprm(bprm); | |
1414 | if (displaced) | |
1415 | put_files_struct(displaced); | |
1416 | return retval; | |
1da177e4 | 1417 | |
a6f76f23 | 1418 | out: |
1da177e4 | 1419 | if (bprm->mm) |
b6a2fea3 | 1420 | mmput (bprm->mm); |
1da177e4 LT |
1421 | |
1422 | out_file: | |
1423 | if (bprm->file) { | |
1424 | allow_write_access(bprm->file); | |
1425 | fput(bprm->file); | |
1426 | } | |
a6f76f23 | 1427 | |
498052bb | 1428 | out_unmark: |
8c652f96 ON |
1429 | if (clear_in_exec) |
1430 | current->fs->in_exec = 0; | |
f9ce1f1c | 1431 | current->in_execve = 0; |
a6f76f23 DH |
1432 | |
1433 | out_free: | |
08a6fac1 | 1434 | free_bprm(bprm); |
1da177e4 | 1435 | |
fd8328be | 1436 | out_files: |
3b125388 AV |
1437 | if (displaced) |
1438 | reset_files_struct(displaced); | |
1da177e4 LT |
1439 | out_ret: |
1440 | return retval; | |
1441 | } | |
1442 | ||
964ee7df | 1443 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1444 | { |
801460d0 HS |
1445 | struct mm_struct *mm = current->mm; |
1446 | ||
1447 | if (mm->binfmt) | |
1448 | module_put(mm->binfmt->module); | |
1da177e4 | 1449 | |
801460d0 | 1450 | mm->binfmt = new; |
964ee7df ON |
1451 | if (new) |
1452 | __module_get(new->module); | |
1da177e4 LT |
1453 | } |
1454 | ||
1455 | EXPORT_SYMBOL(set_binfmt); | |
1456 | ||
1da177e4 LT |
1457 | /* format_corename will inspect the pattern parameter, and output a |
1458 | * name into corename, which must have space for at least | |
1459 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
1460 | */ | |
6409324b | 1461 | static int format_corename(char *corename, long signr) |
1da177e4 | 1462 | { |
86a264ab | 1463 | const struct cred *cred = current_cred(); |
565b9b14 ON |
1464 | const char *pat_ptr = core_pattern; |
1465 | int ispipe = (*pat_ptr == '|'); | |
1da177e4 LT |
1466 | char *out_ptr = corename; |
1467 | char *const out_end = corename + CORENAME_MAX_SIZE; | |
1468 | int rc; | |
1469 | int pid_in_pattern = 0; | |
1470 | ||
1471 | /* Repeat as long as we have more pattern to process and more output | |
1472 | space */ | |
1473 | while (*pat_ptr) { | |
1474 | if (*pat_ptr != '%') { | |
1475 | if (out_ptr == out_end) | |
1476 | goto out; | |
1477 | *out_ptr++ = *pat_ptr++; | |
1478 | } else { | |
1479 | switch (*++pat_ptr) { | |
1480 | case 0: | |
1481 | goto out; | |
1482 | /* Double percent, output one percent */ | |
1483 | case '%': | |
1484 | if (out_ptr == out_end) | |
1485 | goto out; | |
1486 | *out_ptr++ = '%'; | |
1487 | break; | |
1488 | /* pid */ | |
1489 | case 'p': | |
1490 | pid_in_pattern = 1; | |
1491 | rc = snprintf(out_ptr, out_end - out_ptr, | |
b488893a | 1492 | "%d", task_tgid_vnr(current)); |
1da177e4 LT |
1493 | if (rc > out_end - out_ptr) |
1494 | goto out; | |
1495 | out_ptr += rc; | |
1496 | break; | |
1497 | /* uid */ | |
1498 | case 'u': | |
1499 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1500 | "%d", cred->uid); |
1da177e4 LT |
1501 | if (rc > out_end - out_ptr) |
1502 | goto out; | |
1503 | out_ptr += rc; | |
1504 | break; | |
1505 | /* gid */ | |
1506 | case 'g': | |
1507 | rc = snprintf(out_ptr, out_end - out_ptr, | |
86a264ab | 1508 | "%d", cred->gid); |
1da177e4 LT |
1509 | if (rc > out_end - out_ptr) |
1510 | goto out; | |
1511 | out_ptr += rc; | |
1512 | break; | |
1513 | /* signal that caused the coredump */ | |
1514 | case 's': | |
1515 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1516 | "%ld", signr); | |
1517 | if (rc > out_end - out_ptr) | |
1518 | goto out; | |
1519 | out_ptr += rc; | |
1520 | break; | |
1521 | /* UNIX time of coredump */ | |
1522 | case 't': { | |
1523 | struct timeval tv; | |
1524 | do_gettimeofday(&tv); | |
1525 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1526 | "%lu", tv.tv_sec); | |
1527 | if (rc > out_end - out_ptr) | |
1528 | goto out; | |
1529 | out_ptr += rc; | |
1530 | break; | |
1531 | } | |
1532 | /* hostname */ | |
1533 | case 'h': | |
1534 | down_read(&uts_sem); | |
1535 | rc = snprintf(out_ptr, out_end - out_ptr, | |
e9ff3990 | 1536 | "%s", utsname()->nodename); |
1da177e4 LT |
1537 | up_read(&uts_sem); |
1538 | if (rc > out_end - out_ptr) | |
1539 | goto out; | |
1540 | out_ptr += rc; | |
1541 | break; | |
1542 | /* executable */ | |
1543 | case 'e': | |
1544 | rc = snprintf(out_ptr, out_end - out_ptr, | |
1545 | "%s", current->comm); | |
1546 | if (rc > out_end - out_ptr) | |
1547 | goto out; | |
1548 | out_ptr += rc; | |
1549 | break; | |
74aadce9 NH |
1550 | /* core limit size */ |
1551 | case 'c': | |
1552 | rc = snprintf(out_ptr, out_end - out_ptr, | |
d554ed89 | 1553 | "%lu", rlimit(RLIMIT_CORE)); |
74aadce9 NH |
1554 | if (rc > out_end - out_ptr) |
1555 | goto out; | |
1556 | out_ptr += rc; | |
1557 | break; | |
1da177e4 LT |
1558 | default: |
1559 | break; | |
1560 | } | |
1561 | ++pat_ptr; | |
1562 | } | |
1563 | } | |
1564 | /* Backward compatibility with core_uses_pid: | |
1565 | * | |
1566 | * If core_pattern does not include a %p (as is the default) | |
1567 | * and core_uses_pid is set, then .%pid will be appended to | |
c4bbafda | 1568 | * the filename. Do not do this for piped commands. */ |
6409324b | 1569 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
1da177e4 | 1570 | rc = snprintf(out_ptr, out_end - out_ptr, |
b488893a | 1571 | ".%d", task_tgid_vnr(current)); |
1da177e4 LT |
1572 | if (rc > out_end - out_ptr) |
1573 | goto out; | |
1574 | out_ptr += rc; | |
1575 | } | |
c4bbafda | 1576 | out: |
1da177e4 | 1577 | *out_ptr = 0; |
c4bbafda | 1578 | return ispipe; |
1da177e4 LT |
1579 | } |
1580 | ||
5c99cbf4 | 1581 | static int zap_process(struct task_struct *start, int exit_code) |
aceecc04 ON |
1582 | { |
1583 | struct task_struct *t; | |
8cd9c249 | 1584 | int nr = 0; |
281de339 | 1585 | |
d5f70c00 | 1586 | start->signal->flags = SIGNAL_GROUP_EXIT; |
5c99cbf4 | 1587 | start->signal->group_exit_code = exit_code; |
d5f70c00 | 1588 | start->signal->group_stop_count = 0; |
aceecc04 ON |
1589 | |
1590 | t = start; | |
1591 | do { | |
1592 | if (t != current && t->mm) { | |
281de339 ON |
1593 | sigaddset(&t->pending.signal, SIGKILL); |
1594 | signal_wake_up(t, 1); | |
8cd9c249 | 1595 | nr++; |
aceecc04 | 1596 | } |
e4901f92 | 1597 | } while_each_thread(start, t); |
8cd9c249 ON |
1598 | |
1599 | return nr; | |
aceecc04 ON |
1600 | } |
1601 | ||
dcf560c5 | 1602 | static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
8cd9c249 | 1603 | struct core_state *core_state, int exit_code) |
1da177e4 LT |
1604 | { |
1605 | struct task_struct *g, *p; | |
5debfa6d | 1606 | unsigned long flags; |
8cd9c249 | 1607 | int nr = -EAGAIN; |
dcf560c5 ON |
1608 | |
1609 | spin_lock_irq(&tsk->sighand->siglock); | |
ed5d2cac | 1610 | if (!signal_group_exit(tsk->signal)) { |
8cd9c249 | 1611 | mm->core_state = core_state; |
5c99cbf4 | 1612 | nr = zap_process(tsk, exit_code); |
1da177e4 | 1613 | } |
dcf560c5 | 1614 | spin_unlock_irq(&tsk->sighand->siglock); |
8cd9c249 ON |
1615 | if (unlikely(nr < 0)) |
1616 | return nr; | |
1da177e4 | 1617 | |
8cd9c249 | 1618 | if (atomic_read(&mm->mm_users) == nr + 1) |
5debfa6d | 1619 | goto done; |
e4901f92 ON |
1620 | /* |
1621 | * We should find and kill all tasks which use this mm, and we should | |
999d9fc1 | 1622 | * count them correctly into ->nr_threads. We don't take tasklist |
e4901f92 ON |
1623 | * lock, but this is safe wrt: |
1624 | * | |
1625 | * fork: | |
1626 | * None of sub-threads can fork after zap_process(leader). All | |
1627 | * processes which were created before this point should be | |
1628 | * visible to zap_threads() because copy_process() adds the new | |
1629 | * process to the tail of init_task.tasks list, and lock/unlock | |
1630 | * of ->siglock provides a memory barrier. | |
1631 | * | |
1632 | * do_exit: | |
1633 | * The caller holds mm->mmap_sem. This means that the task which | |
1634 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
1635 | * its ->mm. | |
1636 | * | |
1637 | * de_thread: | |
1638 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
1639 | * we must see either old or new leader, this does not matter. | |
1640 | * However, it can change p->sighand, so lock_task_sighand(p) | |
1641 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
1642 | * it can't fail. | |
1643 | * | |
1644 | * Note also that "g" can be the old leader with ->mm == NULL | |
1645 | * and already unhashed and thus removed from ->thread_group. | |
1646 | * This is OK, __unhash_process()->list_del_rcu() does not | |
1647 | * clear the ->next pointer, we will find the new leader via | |
1648 | * next_thread(). | |
1649 | */ | |
7b1c6154 | 1650 | rcu_read_lock(); |
aceecc04 | 1651 | for_each_process(g) { |
5debfa6d ON |
1652 | if (g == tsk->group_leader) |
1653 | continue; | |
15b9f360 ON |
1654 | if (g->flags & PF_KTHREAD) |
1655 | continue; | |
aceecc04 ON |
1656 | p = g; |
1657 | do { | |
1658 | if (p->mm) { | |
15b9f360 | 1659 | if (unlikely(p->mm == mm)) { |
5debfa6d | 1660 | lock_task_sighand(p, &flags); |
5c99cbf4 | 1661 | nr += zap_process(p, exit_code); |
5debfa6d ON |
1662 | unlock_task_sighand(p, &flags); |
1663 | } | |
aceecc04 ON |
1664 | break; |
1665 | } | |
e4901f92 | 1666 | } while_each_thread(g, p); |
aceecc04 | 1667 | } |
7b1c6154 | 1668 | rcu_read_unlock(); |
5debfa6d | 1669 | done: |
c5f1cc8c | 1670 | atomic_set(&core_state->nr_threads, nr); |
8cd9c249 | 1671 | return nr; |
1da177e4 LT |
1672 | } |
1673 | ||
9d5b327b | 1674 | static int coredump_wait(int exit_code, struct core_state *core_state) |
1da177e4 | 1675 | { |
dcf560c5 ON |
1676 | struct task_struct *tsk = current; |
1677 | struct mm_struct *mm = tsk->mm; | |
dcf560c5 | 1678 | struct completion *vfork_done; |
269b005a | 1679 | int core_waiters = -EBUSY; |
1da177e4 | 1680 | |
9d5b327b | 1681 | init_completion(&core_state->startup); |
b564daf8 ON |
1682 | core_state->dumper.task = tsk; |
1683 | core_state->dumper.next = NULL; | |
269b005a ON |
1684 | |
1685 | down_write(&mm->mmap_sem); | |
1686 | if (!mm->core_state) | |
1687 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); | |
2384f55f ON |
1688 | up_write(&mm->mmap_sem); |
1689 | ||
dcf560c5 ON |
1690 | if (unlikely(core_waiters < 0)) |
1691 | goto fail; | |
1692 | ||
1693 | /* | |
1694 | * Make sure nobody is waiting for us to release the VM, | |
1695 | * otherwise we can deadlock when we wait on each other | |
1696 | */ | |
1697 | vfork_done = tsk->vfork_done; | |
1698 | if (vfork_done) { | |
1699 | tsk->vfork_done = NULL; | |
1700 | complete(vfork_done); | |
1701 | } | |
1702 | ||
2384f55f | 1703 | if (core_waiters) |
9d5b327b | 1704 | wait_for_completion(&core_state->startup); |
dcf560c5 | 1705 | fail: |
dcf560c5 | 1706 | return core_waiters; |
1da177e4 LT |
1707 | } |
1708 | ||
a94e2d40 ON |
1709 | static void coredump_finish(struct mm_struct *mm) |
1710 | { | |
1711 | struct core_thread *curr, *next; | |
1712 | struct task_struct *task; | |
1713 | ||
1714 | next = mm->core_state->dumper.next; | |
1715 | while ((curr = next) != NULL) { | |
1716 | next = curr->next; | |
1717 | task = curr->task; | |
1718 | /* | |
1719 | * see exit_mm(), curr->task must not see | |
1720 | * ->task == NULL before we read ->next. | |
1721 | */ | |
1722 | smp_mb(); | |
1723 | curr->task = NULL; | |
1724 | wake_up_process(task); | |
1725 | } | |
1726 | ||
1727 | mm->core_state = NULL; | |
1728 | } | |
1729 | ||
6c5d5238 KH |
1730 | /* |
1731 | * set_dumpable converts traditional three-value dumpable to two flags and | |
1732 | * stores them into mm->flags. It modifies lower two bits of mm->flags, but | |
1733 | * these bits are not changed atomically. So get_dumpable can observe the | |
1734 | * intermediate state. To avoid doing unexpected behavior, get get_dumpable | |
1735 | * return either old dumpable or new one by paying attention to the order of | |
1736 | * modifying the bits. | |
1737 | * | |
1738 | * dumpable | mm->flags (binary) | |
1739 | * old new | initial interim final | |
1740 | * ---------+----------------------- | |
1741 | * 0 1 | 00 01 01 | |
1742 | * 0 2 | 00 10(*) 11 | |
1743 | * 1 0 | 01 00 00 | |
1744 | * 1 2 | 01 11 11 | |
1745 | * 2 0 | 11 10(*) 00 | |
1746 | * 2 1 | 11 11 01 | |
1747 | * | |
1748 | * (*) get_dumpable regards interim value of 10 as 11. | |
1749 | */ | |
1750 | void set_dumpable(struct mm_struct *mm, int value) | |
1751 | { | |
1752 | switch (value) { | |
1753 | case 0: | |
1754 | clear_bit(MMF_DUMPABLE, &mm->flags); | |
1755 | smp_wmb(); | |
1756 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1757 | break; | |
1758 | case 1: | |
1759 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1760 | smp_wmb(); | |
1761 | clear_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1762 | break; | |
1763 | case 2: | |
1764 | set_bit(MMF_DUMP_SECURELY, &mm->flags); | |
1765 | smp_wmb(); | |
1766 | set_bit(MMF_DUMPABLE, &mm->flags); | |
1767 | break; | |
1768 | } | |
1769 | } | |
6c5d5238 | 1770 | |
30736a4d | 1771 | static int __get_dumpable(unsigned long mm_flags) |
6c5d5238 KH |
1772 | { |
1773 | int ret; | |
1774 | ||
30736a4d | 1775 | ret = mm_flags & MMF_DUMPABLE_MASK; |
6c5d5238 KH |
1776 | return (ret >= 2) ? 2 : ret; |
1777 | } | |
1778 | ||
30736a4d MH |
1779 | int get_dumpable(struct mm_struct *mm) |
1780 | { | |
1781 | return __get_dumpable(mm->flags); | |
1782 | } | |
1783 | ||
61be228a NH |
1784 | static void wait_for_dump_helpers(struct file *file) |
1785 | { | |
1786 | struct pipe_inode_info *pipe; | |
1787 | ||
1788 | pipe = file->f_path.dentry->d_inode->i_pipe; | |
1789 | ||
1790 | pipe_lock(pipe); | |
1791 | pipe->readers++; | |
1792 | pipe->writers--; | |
1793 | ||
1794 | while ((pipe->readers > 1) && (!signal_pending(current))) { | |
1795 | wake_up_interruptible_sync(&pipe->wait); | |
1796 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
1797 | pipe_wait(pipe); | |
1798 | } | |
1799 | ||
1800 | pipe->readers--; | |
1801 | pipe->writers++; | |
1802 | pipe_unlock(pipe); | |
1803 | ||
1804 | } | |
1805 | ||
1806 | ||
898b374a NH |
1807 | /* |
1808 | * uhm_pipe_setup | |
1809 | * helper function to customize the process used | |
1810 | * to collect the core in userspace. Specifically | |
1811 | * it sets up a pipe and installs it as fd 0 (stdin) | |
1812 | * for the process. Returns 0 on success, or | |
1813 | * PTR_ERR on failure. | |
1814 | * Note that it also sets the core limit to 1. This | |
1815 | * is a special value that we use to trap recursive | |
1816 | * core dumps | |
1817 | */ | |
1818 | static int umh_pipe_setup(struct subprocess_info *info) | |
1819 | { | |
1820 | struct file *rp, *wp; | |
1821 | struct fdtable *fdt; | |
1822 | struct coredump_params *cp = (struct coredump_params *)info->data; | |
1823 | struct files_struct *cf = current->files; | |
1824 | ||
1825 | wp = create_write_pipe(0); | |
1826 | if (IS_ERR(wp)) | |
1827 | return PTR_ERR(wp); | |
1828 | ||
1829 | rp = create_read_pipe(wp, 0); | |
1830 | if (IS_ERR(rp)) { | |
1831 | free_write_pipe(wp); | |
1832 | return PTR_ERR(rp); | |
1833 | } | |
1834 | ||
1835 | cp->file = wp; | |
1836 | ||
1837 | sys_close(0); | |
1838 | fd_install(0, rp); | |
1839 | spin_lock(&cf->file_lock); | |
1840 | fdt = files_fdtable(cf); | |
1841 | FD_SET(0, fdt->open_fds); | |
1842 | FD_CLR(0, fdt->close_on_exec); | |
1843 | spin_unlock(&cf->file_lock); | |
1844 | ||
1845 | /* and disallow core files too */ | |
1846 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; | |
1847 | ||
1848 | return 0; | |
1849 | } | |
1850 | ||
8cd3ac3a | 1851 | void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
1da177e4 | 1852 | { |
9d5b327b | 1853 | struct core_state core_state; |
1da177e4 LT |
1854 | char corename[CORENAME_MAX_SIZE + 1]; |
1855 | struct mm_struct *mm = current->mm; | |
1856 | struct linux_binfmt * binfmt; | |
d84f4f99 DH |
1857 | const struct cred *old_cred; |
1858 | struct cred *cred; | |
1da177e4 | 1859 | int retval = 0; |
d6e71144 | 1860 | int flag = 0; |
d5bf4c4f | 1861 | int ispipe; |
a293980c | 1862 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
f6151dfe MH |
1863 | struct coredump_params cprm = { |
1864 | .signr = signr, | |
1865 | .regs = regs, | |
d554ed89 | 1866 | .limit = rlimit(RLIMIT_CORE), |
30736a4d MH |
1867 | /* |
1868 | * We must use the same mm->flags while dumping core to avoid | |
1869 | * inconsistency of bit flags, since this flag is not protected | |
1870 | * by any locks. | |
1871 | */ | |
1872 | .mm_flags = mm->flags, | |
f6151dfe | 1873 | }; |
1da177e4 | 1874 | |
0a4ff8c2 SG |
1875 | audit_core_dumps(signr); |
1876 | ||
801460d0 | 1877 | binfmt = mm->binfmt; |
1da177e4 LT |
1878 | if (!binfmt || !binfmt->core_dump) |
1879 | goto fail; | |
269b005a ON |
1880 | if (!__get_dumpable(cprm.mm_flags)) |
1881 | goto fail; | |
d84f4f99 DH |
1882 | |
1883 | cred = prepare_creds(); | |
5e43aef5 | 1884 | if (!cred) |
d84f4f99 | 1885 | goto fail; |
d6e71144 AC |
1886 | /* |
1887 | * We cannot trust fsuid as being the "true" uid of the | |
1888 | * process nor do we know its entire history. We only know it | |
1889 | * was tainted so we dump it as root in mode 2. | |
1890 | */ | |
30736a4d MH |
1891 | if (__get_dumpable(cprm.mm_flags) == 2) { |
1892 | /* Setuid core dump mode */ | |
d6e71144 | 1893 | flag = O_EXCL; /* Stop rewrite attacks */ |
d84f4f99 | 1894 | cred->fsuid = 0; /* Dump root private */ |
d6e71144 | 1895 | } |
1291cf41 | 1896 | |
9d5b327b | 1897 | retval = coredump_wait(exit_code, &core_state); |
5e43aef5 ON |
1898 | if (retval < 0) |
1899 | goto fail_creds; | |
d84f4f99 DH |
1900 | |
1901 | old_cred = override_creds(cred); | |
1da177e4 LT |
1902 | |
1903 | /* | |
1904 | * Clear any false indication of pending signals that might | |
1905 | * be seen by the filesystem code called to write the core file. | |
1906 | */ | |
1da177e4 LT |
1907 | clear_thread_flag(TIF_SIGPENDING); |
1908 | ||
6409324b | 1909 | ispipe = format_corename(corename, signr); |
725eae32 | 1910 | |
c4bbafda | 1911 | if (ispipe) { |
d5bf4c4f ON |
1912 | int dump_count; |
1913 | char **helper_argv; | |
1914 | ||
898b374a | 1915 | if (cprm.limit == 1) { |
725eae32 NH |
1916 | /* |
1917 | * Normally core limits are irrelevant to pipes, since | |
1918 | * we're not writing to the file system, but we use | |
898b374a NH |
1919 | * cprm.limit of 1 here as a speacial value. Any |
1920 | * non-1 limit gets set to RLIM_INFINITY below, but | |
725eae32 NH |
1921 | * a limit of 0 skips the dump. This is a consistent |
1922 | * way to catch recursive crashes. We can still crash | |
898b374a | 1923 | * if the core_pattern binary sets RLIM_CORE = !1 |
725eae32 NH |
1924 | * but it runs as root, and can do lots of stupid things |
1925 | * Note that we use task_tgid_vnr here to grab the pid | |
1926 | * of the process group leader. That way we get the | |
1927 | * right pid if a thread in a multi-threaded | |
1928 | * core_pattern process dies. | |
1929 | */ | |
1930 | printk(KERN_WARNING | |
898b374a | 1931 | "Process %d(%s) has RLIMIT_CORE set to 1\n", |
725eae32 NH |
1932 | task_tgid_vnr(current), current->comm); |
1933 | printk(KERN_WARNING "Aborting core\n"); | |
1934 | goto fail_unlock; | |
1935 | } | |
d5bf4c4f | 1936 | cprm.limit = RLIM_INFINITY; |
725eae32 | 1937 | |
a293980c NH |
1938 | dump_count = atomic_inc_return(&core_dump_count); |
1939 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { | |
1940 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", | |
1941 | task_tgid_vnr(current), current->comm); | |
1942 | printk(KERN_WARNING "Skipping core dump\n"); | |
1943 | goto fail_dropcount; | |
1944 | } | |
1945 | ||
d5bf4c4f | 1946 | helper_argv = argv_split(GFP_KERNEL, corename+1, NULL); |
350eaf79 TH |
1947 | if (!helper_argv) { |
1948 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
1949 | __func__); | |
a293980c | 1950 | goto fail_dropcount; |
350eaf79 | 1951 | } |
32321137 | 1952 | |
d5bf4c4f ON |
1953 | retval = call_usermodehelper_fns(helper_argv[0], helper_argv, |
1954 | NULL, UMH_WAIT_EXEC, umh_pipe_setup, | |
1955 | NULL, &cprm); | |
1956 | argv_free(helper_argv); | |
1957 | if (retval) { | |
d025c9db AK |
1958 | printk(KERN_INFO "Core dump to %s pipe failed\n", |
1959 | corename); | |
d5bf4c4f | 1960 | goto close_fail; |
d025c9db | 1961 | } |
c7135411 ON |
1962 | } else { |
1963 | struct inode *inode; | |
1964 | ||
1965 | if (cprm.limit < binfmt->min_coredump) | |
1966 | goto fail_unlock; | |
1967 | ||
f6151dfe | 1968 | cprm.file = filp_open(corename, |
6d4df677 AD |
1969 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
1970 | 0600); | |
c7135411 ON |
1971 | if (IS_ERR(cprm.file)) |
1972 | goto fail_unlock; | |
1da177e4 | 1973 | |
c7135411 ON |
1974 | inode = cprm.file->f_path.dentry->d_inode; |
1975 | if (inode->i_nlink > 1) | |
1976 | goto close_fail; | |
1977 | if (d_unhashed(cprm.file->f_path.dentry)) | |
1978 | goto close_fail; | |
1979 | /* | |
1980 | * AK: actually i see no reason to not allow this for named | |
1981 | * pipes etc, but keep the previous behaviour for now. | |
1982 | */ | |
1983 | if (!S_ISREG(inode->i_mode)) | |
1984 | goto close_fail; | |
1985 | /* | |
1986 | * Dont allow local users get cute and trick others to coredump | |
1987 | * into their pre-created files. | |
1988 | */ | |
1989 | if (inode->i_uid != current_fsuid()) | |
1990 | goto close_fail; | |
1991 | if (!cprm.file->f_op || !cprm.file->f_op->write) | |
1992 | goto close_fail; | |
1993 | if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) | |
1994 | goto close_fail; | |
1995 | } | |
1da177e4 | 1996 | |
c7135411 | 1997 | retval = binfmt->core_dump(&cprm); |
1da177e4 LT |
1998 | if (retval) |
1999 | current->signal->group_exit_code |= 0x80; | |
d5bf4c4f | 2000 | |
61be228a | 2001 | if (ispipe && core_pipe_limit) |
f6151dfe | 2002 | wait_for_dump_helpers(cprm.file); |
d5bf4c4f ON |
2003 | close_fail: |
2004 | if (cprm.file) | |
2005 | filp_close(cprm.file, NULL); | |
a293980c | 2006 | fail_dropcount: |
d5bf4c4f | 2007 | if (ispipe) |
a293980c | 2008 | atomic_dec(&core_dump_count); |
1da177e4 | 2009 | fail_unlock: |
5e43aef5 | 2010 | coredump_finish(mm); |
d84f4f99 | 2011 | revert_creds(old_cred); |
5e43aef5 | 2012 | fail_creds: |
d84f4f99 | 2013 | put_cred(cred); |
1da177e4 | 2014 | fail: |
8cd3ac3a | 2015 | return; |
1da177e4 | 2016 | } |
3aa0ce82 LT |
2017 | |
2018 | /* | |
2019 | * Core dumping helper functions. These are the only things you should | |
2020 | * do on a core-file: use only these functions to write out all the | |
2021 | * necessary info. | |
2022 | */ | |
2023 | int dump_write(struct file *file, const void *addr, int nr) | |
2024 | { | |
2025 | return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; | |
2026 | } | |
8fd01d6c | 2027 | EXPORT_SYMBOL(dump_write); |
3aa0ce82 LT |
2028 | |
2029 | int dump_seek(struct file *file, loff_t off) | |
2030 | { | |
2031 | int ret = 1; | |
2032 | ||
2033 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { | |
2034 | if (file->f_op->llseek(file, off, SEEK_CUR) < 0) | |
2035 | return 0; | |
2036 | } else { | |
2037 | char *buf = (char *)get_zeroed_page(GFP_KERNEL); | |
2038 | ||
2039 | if (!buf) | |
2040 | return 0; | |
2041 | while (off > 0) { | |
2042 | unsigned long n = off; | |
2043 | ||
2044 | if (n > PAGE_SIZE) | |
2045 | n = PAGE_SIZE; | |
2046 | if (!dump_write(file, buf, n)) { | |
2047 | ret = 0; | |
2048 | break; | |
2049 | } | |
2050 | off -= n; | |
2051 | } | |
2052 | free_page((unsigned long)buf); | |
2053 | } | |
2054 | return ret; | |
2055 | } | |
8fd01d6c | 2056 | EXPORT_SYMBOL(dump_seek); |