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Commit | Line | Data |
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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 | |
613cc2b6 | 22 | * formats. |
1da177e4 LT |
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> |
615d6e87 | 29 | #include <linux/vmacache.h> |
1da177e4 LT |
30 | #include <linux/stat.h> |
31 | #include <linux/fcntl.h> | |
ba92a43d | 32 | #include <linux/swap.h> |
74aadce9 | 33 | #include <linux/string.h> |
1da177e4 | 34 | #include <linux/init.h> |
6e84f315 | 35 | #include <linux/sched/mm.h> |
f7ccbae4 | 36 | #include <linux/sched/coredump.h> |
3f07c014 | 37 | #include <linux/sched/signal.h> |
6a3827d7 | 38 | #include <linux/sched/numa_balancing.h> |
ca5b172b | 39 | #include <linux/pagemap.h> |
cdd6c482 | 40 | #include <linux/perf_event.h> |
1da177e4 LT |
41 | #include <linux/highmem.h> |
42 | #include <linux/spinlock.h> | |
43 | #include <linux/key.h> | |
44 | #include <linux/personality.h> | |
45 | #include <linux/binfmts.h> | |
1da177e4 | 46 | #include <linux/utsname.h> |
84d73786 | 47 | #include <linux/pid_namespace.h> |
1da177e4 LT |
48 | #include <linux/module.h> |
49 | #include <linux/namei.h> | |
1da177e4 LT |
50 | #include <linux/mount.h> |
51 | #include <linux/security.h> | |
52 | #include <linux/syscalls.h> | |
8f0ab514 | 53 | #include <linux/tsacct_kern.h> |
9f46080c | 54 | #include <linux/cn_proc.h> |
473ae30b | 55 | #include <linux/audit.h> |
6341c393 | 56 | #include <linux/tracehook.h> |
5f4123be | 57 | #include <linux/kmod.h> |
6110e3ab | 58 | #include <linux/fsnotify.h> |
5ad4e53b | 59 | #include <linux/fs_struct.h> |
61be228a | 60 | #include <linux/pipe_fs_i.h> |
3d5992d2 | 61 | #include <linux/oom.h> |
0e028465 | 62 | #include <linux/compat.h> |
b44a7dfc | 63 | #include <linux/vmalloc.h> |
1da177e4 | 64 | |
7c0f6ba6 | 65 | #include <linux/uaccess.h> |
1da177e4 | 66 | #include <asm/mmu_context.h> |
b6a2fea3 | 67 | #include <asm/tlb.h> |
43d2b113 KH |
68 | |
69 | #include <trace/events/task.h> | |
a6f76f23 | 70 | #include "internal.h" |
1da177e4 | 71 | |
4ff16c25 DS |
72 | #include <trace/events/sched.h> |
73 | ||
d6e71144 AC |
74 | int suid_dumpable = 0; |
75 | ||
e4dc1b14 | 76 | static LIST_HEAD(formats); |
1da177e4 LT |
77 | static DEFINE_RWLOCK(binfmt_lock); |
78 | ||
8fc3dc5a | 79 | void __register_binfmt(struct linux_binfmt * fmt, int insert) |
1da177e4 | 80 | { |
8fc3dc5a | 81 | BUG_ON(!fmt); |
92eaa565 ON |
82 | if (WARN_ON(!fmt->load_binary)) |
83 | return; | |
1da177e4 | 84 | write_lock(&binfmt_lock); |
74641f58 IK |
85 | insert ? list_add(&fmt->lh, &formats) : |
86 | list_add_tail(&fmt->lh, &formats); | |
1da177e4 | 87 | write_unlock(&binfmt_lock); |
1da177e4 LT |
88 | } |
89 | ||
74641f58 | 90 | EXPORT_SYMBOL(__register_binfmt); |
1da177e4 | 91 | |
f6b450d4 | 92 | void unregister_binfmt(struct linux_binfmt * fmt) |
1da177e4 | 93 | { |
1da177e4 | 94 | write_lock(&binfmt_lock); |
e4dc1b14 | 95 | list_del(&fmt->lh); |
1da177e4 | 96 | write_unlock(&binfmt_lock); |
1da177e4 LT |
97 | } |
98 | ||
99 | EXPORT_SYMBOL(unregister_binfmt); | |
100 | ||
101 | static inline void put_binfmt(struct linux_binfmt * fmt) | |
102 | { | |
103 | module_put(fmt->module); | |
104 | } | |
105 | ||
90f8572b EB |
106 | bool path_noexec(const struct path *path) |
107 | { | |
108 | return (path->mnt->mnt_flags & MNT_NOEXEC) || | |
109 | (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC); | |
110 | } | |
111 | ||
69369a70 | 112 | #ifdef CONFIG_USELIB |
1da177e4 LT |
113 | /* |
114 | * Note that a shared library must be both readable and executable due to | |
115 | * security reasons. | |
116 | * | |
117 | * Also note that we take the address to load from from the file itself. | |
118 | */ | |
1e7bfb21 | 119 | SYSCALL_DEFINE1(uselib, const char __user *, library) |
1da177e4 | 120 | { |
72c2d531 | 121 | struct linux_binfmt *fmt; |
964bd183 | 122 | struct file *file; |
91a27b2a | 123 | struct filename *tmp = getname(library); |
964bd183 | 124 | int error = PTR_ERR(tmp); |
47c805dc AV |
125 | static const struct open_flags uselib_flags = { |
126 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, | |
62fb4a15 | 127 | .acc_mode = MAY_READ | MAY_EXEC, |
f9652e10 AV |
128 | .intent = LOOKUP_OPEN, |
129 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 130 | }; |
964bd183 | 131 | |
6e8341a1 AV |
132 | if (IS_ERR(tmp)) |
133 | goto out; | |
134 | ||
f9652e10 | 135 | file = do_filp_open(AT_FDCWD, tmp, &uselib_flags); |
6e8341a1 AV |
136 | putname(tmp); |
137 | error = PTR_ERR(file); | |
138 | if (IS_ERR(file)) | |
1da177e4 LT |
139 | goto out; |
140 | ||
141 | error = -EINVAL; | |
496ad9aa | 142 | if (!S_ISREG(file_inode(file)->i_mode)) |
1da177e4 LT |
143 | goto exit; |
144 | ||
30524472 | 145 | error = -EACCES; |
90f8572b | 146 | if (path_noexec(&file->f_path)) |
1da177e4 LT |
147 | goto exit; |
148 | ||
2a12a9d7 | 149 | fsnotify_open(file); |
6110e3ab | 150 | |
1da177e4 | 151 | error = -ENOEXEC; |
1da177e4 | 152 | |
72c2d531 AV |
153 | read_lock(&binfmt_lock); |
154 | list_for_each_entry(fmt, &formats, lh) { | |
155 | if (!fmt->load_shlib) | |
156 | continue; | |
157 | if (!try_module_get(fmt->module)) | |
158 | continue; | |
1da177e4 | 159 | read_unlock(&binfmt_lock); |
72c2d531 AV |
160 | error = fmt->load_shlib(file); |
161 | read_lock(&binfmt_lock); | |
162 | put_binfmt(fmt); | |
163 | if (error != -ENOEXEC) | |
164 | break; | |
1da177e4 | 165 | } |
72c2d531 | 166 | read_unlock(&binfmt_lock); |
6e8341a1 | 167 | exit: |
1da177e4 LT |
168 | fput(file); |
169 | out: | |
170 | return error; | |
1da177e4 | 171 | } |
69369a70 | 172 | #endif /* #ifdef CONFIG_USELIB */ |
1da177e4 | 173 | |
b6a2fea3 | 174 | #ifdef CONFIG_MMU |
ae6b585e ON |
175 | /* |
176 | * The nascent bprm->mm is not visible until exec_mmap() but it can | |
177 | * use a lot of memory, account these pages in current->mm temporary | |
178 | * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we | |
179 | * change the counter back via acct_arg_size(0). | |
180 | */ | |
0e028465 | 181 | static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
182 | { |
183 | struct mm_struct *mm = current->mm; | |
184 | long diff = (long)(pages - bprm->vma_pages); | |
185 | ||
186 | if (!mm || !diff) | |
187 | return; | |
188 | ||
189 | bprm->vma_pages = pages; | |
3c77f845 | 190 | add_mm_counter(mm, MM_ANONPAGES, diff); |
3c77f845 ON |
191 | } |
192 | ||
0e028465 | 193 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
194 | int write) |
195 | { | |
196 | struct page *page; | |
197 | int ret; | |
9beae1ea | 198 | unsigned int gup_flags = FOLL_FORCE; |
b6a2fea3 OW |
199 | |
200 | #ifdef CONFIG_STACK_GROWSUP | |
201 | if (write) { | |
d05f3169 | 202 | ret = expand_downwards(bprm->vma, pos); |
b6a2fea3 OW |
203 | if (ret < 0) |
204 | return NULL; | |
205 | } | |
206 | #endif | |
9beae1ea LS |
207 | |
208 | if (write) | |
209 | gup_flags |= FOLL_WRITE; | |
210 | ||
1e987790 DH |
211 | /* |
212 | * We are doing an exec(). 'current' is the process | |
213 | * doing the exec and bprm->mm is the new process's mm. | |
214 | */ | |
9beae1ea | 215 | ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags, |
5b56d49f | 216 | &page, NULL, NULL); |
b6a2fea3 OW |
217 | if (ret <= 0) |
218 | return NULL; | |
219 | ||
220 | if (write) { | |
b6a2fea3 | 221 | unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
a64e715f LT |
222 | struct rlimit *rlim; |
223 | ||
3c77f845 ON |
224 | acct_arg_size(bprm, size / PAGE_SIZE); |
225 | ||
a64e715f LT |
226 | /* |
227 | * We've historically supported up to 32 pages (ARG_MAX) | |
228 | * of argument strings even with small stacks | |
229 | */ | |
230 | if (size <= ARG_MAX) | |
231 | return page; | |
b6a2fea3 OW |
232 | |
233 | /* | |
234 | * Limit to 1/4-th the stack size for the argv+env strings. | |
235 | * This ensures that: | |
236 | * - the remaining binfmt code will not run out of stack space, | |
237 | * - the program will have a reasonable amount of stack left | |
238 | * to work from. | |
239 | */ | |
a64e715f | 240 | rlim = current->signal->rlim; |
d554ed89 | 241 | if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
b6a2fea3 OW |
242 | put_page(page); |
243 | return NULL; | |
244 | } | |
245 | } | |
246 | ||
247 | return page; | |
248 | } | |
249 | ||
250 | static void put_arg_page(struct page *page) | |
251 | { | |
252 | put_page(page); | |
253 | } | |
254 | ||
b6a2fea3 OW |
255 | static void free_arg_pages(struct linux_binprm *bprm) |
256 | { | |
257 | } | |
258 | ||
259 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
260 | struct page *page) | |
261 | { | |
262 | flush_cache_page(bprm->vma, pos, page_to_pfn(page)); | |
263 | } | |
264 | ||
265 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
266 | { | |
eaccbfa5 | 267 | int err; |
b6a2fea3 OW |
268 | struct vm_area_struct *vma = NULL; |
269 | struct mm_struct *mm = bprm->mm; | |
270 | ||
271 | bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); | |
272 | if (!vma) | |
eaccbfa5 | 273 | return -ENOMEM; |
b6a2fea3 | 274 | |
f268dfe9 MH |
275 | if (down_write_killable(&mm->mmap_sem)) { |
276 | err = -EINTR; | |
277 | goto err_free; | |
278 | } | |
b6a2fea3 OW |
279 | vma->vm_mm = mm; |
280 | ||
281 | /* | |
282 | * Place the stack at the largest stack address the architecture | |
283 | * supports. Later, we'll move this to an appropriate place. We don't | |
284 | * use STACK_TOP because that can depend on attributes which aren't | |
285 | * configured yet. | |
286 | */ | |
aacb3d17 | 287 | BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
b6a2fea3 OW |
288 | vma->vm_end = STACK_TOP_MAX; |
289 | vma->vm_start = vma->vm_end - PAGE_SIZE; | |
d9104d1c | 290 | vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
3ed75eb8 | 291 | vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); |
5beb4930 | 292 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
462e635e | 293 | |
b6a2fea3 | 294 | err = insert_vm_struct(mm, vma); |
eaccbfa5 | 295 | if (err) |
b6a2fea3 | 296 | goto err; |
b6a2fea3 OW |
297 | |
298 | mm->stack_vm = mm->total_vm = 1; | |
fe3d197f | 299 | arch_bprm_mm_init(mm, vma); |
b6a2fea3 | 300 | up_write(&mm->mmap_sem); |
b6a2fea3 | 301 | bprm->p = vma->vm_end - sizeof(void *); |
b6a2fea3 | 302 | return 0; |
b6a2fea3 | 303 | err: |
eaccbfa5 | 304 | up_write(&mm->mmap_sem); |
f268dfe9 | 305 | err_free: |
eaccbfa5 LFC |
306 | bprm->vma = NULL; |
307 | kmem_cache_free(vm_area_cachep, vma); | |
b6a2fea3 OW |
308 | return err; |
309 | } | |
310 | ||
311 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
312 | { | |
313 | return len <= MAX_ARG_STRLEN; | |
314 | } | |
315 | ||
316 | #else | |
317 | ||
0e028465 | 318 | static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
3c77f845 ON |
319 | { |
320 | } | |
321 | ||
0e028465 | 322 | static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
b6a2fea3 OW |
323 | int write) |
324 | { | |
325 | struct page *page; | |
326 | ||
327 | page = bprm->page[pos / PAGE_SIZE]; | |
328 | if (!page && write) { | |
329 | page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); | |
330 | if (!page) | |
331 | return NULL; | |
332 | bprm->page[pos / PAGE_SIZE] = page; | |
333 | } | |
334 | ||
335 | return page; | |
336 | } | |
337 | ||
338 | static void put_arg_page(struct page *page) | |
339 | { | |
340 | } | |
341 | ||
342 | static void free_arg_page(struct linux_binprm *bprm, int i) | |
343 | { | |
344 | if (bprm->page[i]) { | |
345 | __free_page(bprm->page[i]); | |
346 | bprm->page[i] = NULL; | |
347 | } | |
348 | } | |
349 | ||
350 | static void free_arg_pages(struct linux_binprm *bprm) | |
351 | { | |
352 | int i; | |
353 | ||
354 | for (i = 0; i < MAX_ARG_PAGES; i++) | |
355 | free_arg_page(bprm, i); | |
356 | } | |
357 | ||
358 | static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, | |
359 | struct page *page) | |
360 | { | |
361 | } | |
362 | ||
363 | static int __bprm_mm_init(struct linux_binprm *bprm) | |
364 | { | |
365 | bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); | |
366 | return 0; | |
367 | } | |
368 | ||
369 | static bool valid_arg_len(struct linux_binprm *bprm, long len) | |
370 | { | |
371 | return len <= bprm->p; | |
372 | } | |
373 | ||
374 | #endif /* CONFIG_MMU */ | |
375 | ||
376 | /* | |
377 | * Create a new mm_struct and populate it with a temporary stack | |
378 | * vm_area_struct. We don't have enough context at this point to set the stack | |
379 | * flags, permissions, and offset, so we use temporary values. We'll update | |
380 | * them later in setup_arg_pages(). | |
381 | */ | |
9cc64cea | 382 | static int bprm_mm_init(struct linux_binprm *bprm) |
b6a2fea3 OW |
383 | { |
384 | int err; | |
385 | struct mm_struct *mm = NULL; | |
386 | ||
387 | bprm->mm = mm = mm_alloc(); | |
388 | err = -ENOMEM; | |
389 | if (!mm) | |
390 | goto err; | |
391 | ||
b6a2fea3 OW |
392 | err = __bprm_mm_init(bprm); |
393 | if (err) | |
394 | goto err; | |
395 | ||
396 | return 0; | |
397 | ||
398 | err: | |
399 | if (mm) { | |
400 | bprm->mm = NULL; | |
401 | mmdrop(mm); | |
402 | } | |
403 | ||
404 | return err; | |
405 | } | |
406 | ||
ba2d0162 | 407 | struct user_arg_ptr { |
0e028465 ON |
408 | #ifdef CONFIG_COMPAT |
409 | bool is_compat; | |
410 | #endif | |
411 | union { | |
412 | const char __user *const __user *native; | |
413 | #ifdef CONFIG_COMPAT | |
38b983b3 | 414 | const compat_uptr_t __user *compat; |
0e028465 ON |
415 | #endif |
416 | } ptr; | |
ba2d0162 ON |
417 | }; |
418 | ||
419 | static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) | |
1d1dbf81 | 420 | { |
0e028465 ON |
421 | const char __user *native; |
422 | ||
423 | #ifdef CONFIG_COMPAT | |
424 | if (unlikely(argv.is_compat)) { | |
425 | compat_uptr_t compat; | |
426 | ||
427 | if (get_user(compat, argv.ptr.compat + nr)) | |
428 | return ERR_PTR(-EFAULT); | |
1d1dbf81 | 429 | |
0e028465 ON |
430 | return compat_ptr(compat); |
431 | } | |
432 | #endif | |
433 | ||
434 | if (get_user(native, argv.ptr.native + nr)) | |
1d1dbf81 ON |
435 | return ERR_PTR(-EFAULT); |
436 | ||
0e028465 | 437 | return native; |
1d1dbf81 ON |
438 | } |
439 | ||
1da177e4 LT |
440 | /* |
441 | * count() counts the number of strings in array ARGV. | |
442 | */ | |
ba2d0162 | 443 | static int count(struct user_arg_ptr argv, int max) |
1da177e4 LT |
444 | { |
445 | int i = 0; | |
446 | ||
0e028465 | 447 | if (argv.ptr.native != NULL) { |
1da177e4 | 448 | for (;;) { |
1d1dbf81 | 449 | const char __user *p = get_user_arg_ptr(argv, i); |
1da177e4 | 450 | |
1da177e4 LT |
451 | if (!p) |
452 | break; | |
1d1dbf81 ON |
453 | |
454 | if (IS_ERR(p)) | |
455 | return -EFAULT; | |
456 | ||
6d92d4f6 | 457 | if (i >= max) |
1da177e4 | 458 | return -E2BIG; |
6d92d4f6 | 459 | ++i; |
9aea5a65 RM |
460 | |
461 | if (fatal_signal_pending(current)) | |
462 | return -ERESTARTNOHAND; | |
1da177e4 LT |
463 | cond_resched(); |
464 | } | |
465 | } | |
466 | return i; | |
467 | } | |
468 | ||
469 | /* | |
b6a2fea3 OW |
470 | * 'copy_strings()' copies argument/environment strings from the old |
471 | * processes's memory to the new process's stack. The call to get_user_pages() | |
472 | * ensures the destination page is created and not swapped out. | |
1da177e4 | 473 | */ |
ba2d0162 | 474 | static int copy_strings(int argc, struct user_arg_ptr argv, |
75c96f85 | 475 | struct linux_binprm *bprm) |
1da177e4 LT |
476 | { |
477 | struct page *kmapped_page = NULL; | |
478 | char *kaddr = NULL; | |
b6a2fea3 | 479 | unsigned long kpos = 0; |
1da177e4 LT |
480 | int ret; |
481 | ||
482 | while (argc-- > 0) { | |
d7627467 | 483 | const char __user *str; |
1da177e4 LT |
484 | int len; |
485 | unsigned long pos; | |
486 | ||
1d1dbf81 ON |
487 | ret = -EFAULT; |
488 | str = get_user_arg_ptr(argv, argc); | |
489 | if (IS_ERR(str)) | |
1da177e4 | 490 | goto out; |
1da177e4 | 491 | |
1d1dbf81 ON |
492 | len = strnlen_user(str, MAX_ARG_STRLEN); |
493 | if (!len) | |
494 | goto out; | |
495 | ||
496 | ret = -E2BIG; | |
497 | if (!valid_arg_len(bprm, len)) | |
1da177e4 | 498 | goto out; |
1da177e4 | 499 | |
b6a2fea3 | 500 | /* We're going to work our way backwords. */ |
1da177e4 | 501 | pos = bprm->p; |
b6a2fea3 OW |
502 | str += len; |
503 | bprm->p -= len; | |
1da177e4 LT |
504 | |
505 | while (len > 0) { | |
1da177e4 | 506 | int offset, bytes_to_copy; |
1da177e4 | 507 | |
9aea5a65 RM |
508 | if (fatal_signal_pending(current)) { |
509 | ret = -ERESTARTNOHAND; | |
510 | goto out; | |
511 | } | |
7993bc1f RM |
512 | cond_resched(); |
513 | ||
1da177e4 | 514 | offset = pos % PAGE_SIZE; |
b6a2fea3 OW |
515 | if (offset == 0) |
516 | offset = PAGE_SIZE; | |
517 | ||
518 | bytes_to_copy = offset; | |
519 | if (bytes_to_copy > len) | |
520 | bytes_to_copy = len; | |
521 | ||
522 | offset -= bytes_to_copy; | |
523 | pos -= bytes_to_copy; | |
524 | str -= bytes_to_copy; | |
525 | len -= bytes_to_copy; | |
526 | ||
527 | if (!kmapped_page || kpos != (pos & PAGE_MASK)) { | |
528 | struct page *page; | |
529 | ||
530 | page = get_arg_page(bprm, pos, 1); | |
1da177e4 | 531 | if (!page) { |
b6a2fea3 | 532 | ret = -E2BIG; |
1da177e4 LT |
533 | goto out; |
534 | } | |
1da177e4 | 535 | |
b6a2fea3 OW |
536 | if (kmapped_page) { |
537 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 538 | kunmap(kmapped_page); |
b6a2fea3 OW |
539 | put_arg_page(kmapped_page); |
540 | } | |
1da177e4 LT |
541 | kmapped_page = page; |
542 | kaddr = kmap(kmapped_page); | |
b6a2fea3 OW |
543 | kpos = pos & PAGE_MASK; |
544 | flush_arg_page(bprm, kpos, kmapped_page); | |
1da177e4 | 545 | } |
b6a2fea3 | 546 | if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
1da177e4 LT |
547 | ret = -EFAULT; |
548 | goto out; | |
549 | } | |
1da177e4 LT |
550 | } |
551 | } | |
552 | ret = 0; | |
553 | out: | |
b6a2fea3 OW |
554 | if (kmapped_page) { |
555 | flush_kernel_dcache_page(kmapped_page); | |
1da177e4 | 556 | kunmap(kmapped_page); |
b6a2fea3 OW |
557 | put_arg_page(kmapped_page); |
558 | } | |
1da177e4 LT |
559 | return ret; |
560 | } | |
561 | ||
562 | /* | |
563 | * Like copy_strings, but get argv and its values from kernel memory. | |
564 | */ | |
ba2d0162 | 565 | int copy_strings_kernel(int argc, const char *const *__argv, |
d7627467 | 566 | struct linux_binprm *bprm) |
1da177e4 LT |
567 | { |
568 | int r; | |
569 | mm_segment_t oldfs = get_fs(); | |
ba2d0162 | 570 | struct user_arg_ptr argv = { |
0e028465 | 571 | .ptr.native = (const char __user *const __user *)__argv, |
ba2d0162 ON |
572 | }; |
573 | ||
1da177e4 | 574 | set_fs(KERNEL_DS); |
ba2d0162 | 575 | r = copy_strings(argc, argv, bprm); |
1da177e4 | 576 | set_fs(oldfs); |
ba2d0162 | 577 | |
1da177e4 LT |
578 | return r; |
579 | } | |
1da177e4 LT |
580 | EXPORT_SYMBOL(copy_strings_kernel); |
581 | ||
582 | #ifdef CONFIG_MMU | |
b6a2fea3 | 583 | |
1da177e4 | 584 | /* |
b6a2fea3 OW |
585 | * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
586 | * the binfmt code determines where the new stack should reside, we shift it to | |
587 | * its final location. The process proceeds as follows: | |
1da177e4 | 588 | * |
b6a2fea3 OW |
589 | * 1) Use shift to calculate the new vma endpoints. |
590 | * 2) Extend vma to cover both the old and new ranges. This ensures the | |
591 | * arguments passed to subsequent functions are consistent. | |
592 | * 3) Move vma's page tables to the new range. | |
593 | * 4) Free up any cleared pgd range. | |
594 | * 5) Shrink the vma to cover only the new range. | |
1da177e4 | 595 | */ |
b6a2fea3 | 596 | static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
1da177e4 LT |
597 | { |
598 | struct mm_struct *mm = vma->vm_mm; | |
b6a2fea3 OW |
599 | unsigned long old_start = vma->vm_start; |
600 | unsigned long old_end = vma->vm_end; | |
601 | unsigned long length = old_end - old_start; | |
602 | unsigned long new_start = old_start - shift; | |
603 | unsigned long new_end = old_end - shift; | |
d16dfc55 | 604 | struct mmu_gather tlb; |
1da177e4 | 605 | |
b6a2fea3 | 606 | BUG_ON(new_start > new_end); |
1da177e4 | 607 | |
b6a2fea3 OW |
608 | /* |
609 | * ensure there are no vmas between where we want to go | |
610 | * and where we are | |
611 | */ | |
612 | if (vma != find_vma(mm, new_start)) | |
613 | return -EFAULT; | |
614 | ||
615 | /* | |
616 | * cover the whole range: [new_start, old_end) | |
617 | */ | |
5beb4930 RR |
618 | if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
619 | return -ENOMEM; | |
b6a2fea3 OW |
620 | |
621 | /* | |
622 | * move the page tables downwards, on failure we rely on | |
623 | * process cleanup to remove whatever mess we made. | |
624 | */ | |
625 | if (length != move_page_tables(vma, old_start, | |
38a76013 | 626 | vma, new_start, length, false)) |
b6a2fea3 OW |
627 | return -ENOMEM; |
628 | ||
629 | lru_add_drain(); | |
2b047252 | 630 | tlb_gather_mmu(&tlb, mm, old_start, old_end); |
b6a2fea3 OW |
631 | if (new_end > old_start) { |
632 | /* | |
633 | * when the old and new regions overlap clear from new_end. | |
634 | */ | |
d16dfc55 | 635 | free_pgd_range(&tlb, new_end, old_end, new_end, |
6ee8630e | 636 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
b6a2fea3 OW |
637 | } else { |
638 | /* | |
639 | * otherwise, clean from old_start; this is done to not touch | |
640 | * the address space in [new_end, old_start) some architectures | |
641 | * have constraints on va-space that make this illegal (IA64) - | |
642 | * for the others its just a little faster. | |
643 | */ | |
d16dfc55 | 644 | free_pgd_range(&tlb, old_start, old_end, new_end, |
6ee8630e | 645 | vma->vm_next ? vma->vm_next->vm_start : USER_PGTABLES_CEILING); |
1da177e4 | 646 | } |
2b047252 | 647 | tlb_finish_mmu(&tlb, old_start, old_end); |
b6a2fea3 OW |
648 | |
649 | /* | |
5beb4930 | 650 | * Shrink the vma to just the new range. Always succeeds. |
b6a2fea3 OW |
651 | */ |
652 | vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); | |
653 | ||
654 | return 0; | |
1da177e4 LT |
655 | } |
656 | ||
b6a2fea3 OW |
657 | /* |
658 | * Finalizes the stack vm_area_struct. The flags and permissions are updated, | |
659 | * the stack is optionally relocated, and some extra space is added. | |
660 | */ | |
1da177e4 LT |
661 | int setup_arg_pages(struct linux_binprm *bprm, |
662 | unsigned long stack_top, | |
663 | int executable_stack) | |
664 | { | |
b6a2fea3 OW |
665 | unsigned long ret; |
666 | unsigned long stack_shift; | |
1da177e4 | 667 | struct mm_struct *mm = current->mm; |
b6a2fea3 OW |
668 | struct vm_area_struct *vma = bprm->vma; |
669 | struct vm_area_struct *prev = NULL; | |
670 | unsigned long vm_flags; | |
671 | unsigned long stack_base; | |
803bf5ec MN |
672 | unsigned long stack_size; |
673 | unsigned long stack_expand; | |
674 | unsigned long rlim_stack; | |
1da177e4 LT |
675 | |
676 | #ifdef CONFIG_STACK_GROWSUP | |
d71f290b | 677 | /* Limit stack size */ |
d554ed89 | 678 | stack_base = rlimit_max(RLIMIT_STACK); |
d71f290b JH |
679 | if (stack_base > STACK_SIZE_MAX) |
680 | stack_base = STACK_SIZE_MAX; | |
1da177e4 | 681 | |
d045c77c HD |
682 | /* Add space for stack randomization. */ |
683 | stack_base += (STACK_RND_MASK << PAGE_SHIFT); | |
684 | ||
b6a2fea3 OW |
685 | /* Make sure we didn't let the argument array grow too large. */ |
686 | if (vma->vm_end - vma->vm_start > stack_base) | |
687 | return -ENOMEM; | |
1da177e4 | 688 | |
b6a2fea3 | 689 | stack_base = PAGE_ALIGN(stack_top - stack_base); |
1da177e4 | 690 | |
b6a2fea3 OW |
691 | stack_shift = vma->vm_start - stack_base; |
692 | mm->arg_start = bprm->p - stack_shift; | |
693 | bprm->p = vma->vm_end - stack_shift; | |
1da177e4 | 694 | #else |
b6a2fea3 OW |
695 | stack_top = arch_align_stack(stack_top); |
696 | stack_top = PAGE_ALIGN(stack_top); | |
1b528181 RM |
697 | |
698 | if (unlikely(stack_top < mmap_min_addr) || | |
699 | unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) | |
700 | return -ENOMEM; | |
701 | ||
b6a2fea3 OW |
702 | stack_shift = vma->vm_end - stack_top; |
703 | ||
704 | bprm->p -= stack_shift; | |
1da177e4 | 705 | mm->arg_start = bprm->p; |
1da177e4 LT |
706 | #endif |
707 | ||
1da177e4 | 708 | if (bprm->loader) |
b6a2fea3 OW |
709 | bprm->loader -= stack_shift; |
710 | bprm->exec -= stack_shift; | |
1da177e4 | 711 | |
f268dfe9 MH |
712 | if (down_write_killable(&mm->mmap_sem)) |
713 | return -EINTR; | |
714 | ||
96a8e13e | 715 | vm_flags = VM_STACK_FLAGS; |
b6a2fea3 OW |
716 | |
717 | /* | |
718 | * Adjust stack execute permissions; explicitly enable for | |
719 | * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone | |
720 | * (arch default) otherwise. | |
721 | */ | |
722 | if (unlikely(executable_stack == EXSTACK_ENABLE_X)) | |
723 | vm_flags |= VM_EXEC; | |
724 | else if (executable_stack == EXSTACK_DISABLE_X) | |
725 | vm_flags &= ~VM_EXEC; | |
726 | vm_flags |= mm->def_flags; | |
a8bef8ff | 727 | vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
b6a2fea3 OW |
728 | |
729 | ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, | |
730 | vm_flags); | |
731 | if (ret) | |
732 | goto out_unlock; | |
733 | BUG_ON(prev != vma); | |
734 | ||
735 | /* Move stack pages down in memory. */ | |
736 | if (stack_shift) { | |
737 | ret = shift_arg_pages(vma, stack_shift); | |
fc63cf23 AB |
738 | if (ret) |
739 | goto out_unlock; | |
1da177e4 LT |
740 | } |
741 | ||
a8bef8ff MG |
742 | /* mprotect_fixup is overkill to remove the temporary stack flags */ |
743 | vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; | |
744 | ||
5ef097dd | 745 | stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ |
803bf5ec MN |
746 | stack_size = vma->vm_end - vma->vm_start; |
747 | /* | |
748 | * Align this down to a page boundary as expand_stack | |
749 | * will align it up. | |
750 | */ | |
751 | rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; | |
b6a2fea3 | 752 | #ifdef CONFIG_STACK_GROWSUP |
803bf5ec MN |
753 | if (stack_size + stack_expand > rlim_stack) |
754 | stack_base = vma->vm_start + rlim_stack; | |
755 | else | |
756 | stack_base = vma->vm_end + stack_expand; | |
b6a2fea3 | 757 | #else |
803bf5ec MN |
758 | if (stack_size + stack_expand > rlim_stack) |
759 | stack_base = vma->vm_end - rlim_stack; | |
760 | else | |
761 | stack_base = vma->vm_start - stack_expand; | |
b6a2fea3 | 762 | #endif |
3af9e859 | 763 | current->mm->start_stack = bprm->p; |
b6a2fea3 OW |
764 | ret = expand_stack(vma, stack_base); |
765 | if (ret) | |
766 | ret = -EFAULT; | |
767 | ||
768 | out_unlock: | |
1da177e4 | 769 | up_write(&mm->mmap_sem); |
fc63cf23 | 770 | return ret; |
1da177e4 | 771 | } |
1da177e4 LT |
772 | EXPORT_SYMBOL(setup_arg_pages); |
773 | ||
7e7ec6a9 NP |
774 | #else |
775 | ||
776 | /* | |
777 | * Transfer the program arguments and environment from the holding pages | |
778 | * onto the stack. The provided stack pointer is adjusted accordingly. | |
779 | */ | |
780 | int transfer_args_to_stack(struct linux_binprm *bprm, | |
781 | unsigned long *sp_location) | |
782 | { | |
783 | unsigned long index, stop, sp; | |
784 | int ret = 0; | |
785 | ||
786 | stop = bprm->p >> PAGE_SHIFT; | |
787 | sp = *sp_location; | |
788 | ||
789 | for (index = MAX_ARG_PAGES - 1; index >= stop; index--) { | |
790 | unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0; | |
791 | char *src = kmap(bprm->page[index]) + offset; | |
792 | sp -= PAGE_SIZE - offset; | |
793 | if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0) | |
794 | ret = -EFAULT; | |
795 | kunmap(bprm->page[index]); | |
796 | if (ret) | |
797 | goto out; | |
798 | } | |
799 | ||
800 | *sp_location = sp; | |
801 | ||
802 | out: | |
803 | return ret; | |
804 | } | |
805 | EXPORT_SYMBOL(transfer_args_to_stack); | |
806 | ||
1da177e4 LT |
807 | #endif /* CONFIG_MMU */ |
808 | ||
51f39a1f | 809 | static struct file *do_open_execat(int fd, struct filename *name, int flags) |
1da177e4 | 810 | { |
1da177e4 | 811 | struct file *file; |
e56b6a5d | 812 | int err; |
51f39a1f | 813 | struct open_flags open_exec_flags = { |
47c805dc | 814 | .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
62fb4a15 | 815 | .acc_mode = MAY_EXEC, |
f9652e10 AV |
816 | .intent = LOOKUP_OPEN, |
817 | .lookup_flags = LOOKUP_FOLLOW, | |
47c805dc | 818 | }; |
1da177e4 | 819 | |
51f39a1f DD |
820 | if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
821 | return ERR_PTR(-EINVAL); | |
822 | if (flags & AT_SYMLINK_NOFOLLOW) | |
823 | open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW; | |
824 | if (flags & AT_EMPTY_PATH) | |
825 | open_exec_flags.lookup_flags |= LOOKUP_EMPTY; | |
826 | ||
827 | file = do_filp_open(fd, name, &open_exec_flags); | |
6e8341a1 | 828 | if (IS_ERR(file)) |
e56b6a5d CH |
829 | goto out; |
830 | ||
831 | err = -EACCES; | |
496ad9aa | 832 | if (!S_ISREG(file_inode(file)->i_mode)) |
6e8341a1 | 833 | goto exit; |
e56b6a5d | 834 | |
90f8572b | 835 | if (path_noexec(&file->f_path)) |
6e8341a1 | 836 | goto exit; |
e56b6a5d CH |
837 | |
838 | err = deny_write_access(file); | |
6e8341a1 AV |
839 | if (err) |
840 | goto exit; | |
1da177e4 | 841 | |
51f39a1f DD |
842 | if (name->name[0] != '\0') |
843 | fsnotify_open(file); | |
844 | ||
6e8341a1 | 845 | out: |
e56b6a5d CH |
846 | return file; |
847 | ||
6e8341a1 AV |
848 | exit: |
849 | fput(file); | |
e56b6a5d CH |
850 | return ERR_PTR(err); |
851 | } | |
c4ad8f98 LT |
852 | |
853 | struct file *open_exec(const char *name) | |
854 | { | |
51689104 PM |
855 | struct filename *filename = getname_kernel(name); |
856 | struct file *f = ERR_CAST(filename); | |
857 | ||
858 | if (!IS_ERR(filename)) { | |
859 | f = do_open_execat(AT_FDCWD, filename, 0); | |
860 | putname(filename); | |
861 | } | |
862 | return f; | |
c4ad8f98 | 863 | } |
1da177e4 LT |
864 | EXPORT_SYMBOL(open_exec); |
865 | ||
6777d773 MZ |
866 | int kernel_read(struct file *file, loff_t offset, |
867 | char *addr, unsigned long count) | |
1da177e4 LT |
868 | { |
869 | mm_segment_t old_fs; | |
870 | loff_t pos = offset; | |
871 | int result; | |
872 | ||
873 | old_fs = get_fs(); | |
874 | set_fs(get_ds()); | |
875 | /* The cast to a user pointer is valid due to the set_fs() */ | |
876 | result = vfs_read(file, (void __user *)addr, count, &pos); | |
877 | set_fs(old_fs); | |
878 | return result; | |
879 | } | |
880 | ||
881 | EXPORT_SYMBOL(kernel_read); | |
882 | ||
b44a7dfc | 883 | int kernel_read_file(struct file *file, void **buf, loff_t *size, |
bc8ca5b9 | 884 | loff_t max_size, enum kernel_read_file_id id) |
b44a7dfc MZ |
885 | { |
886 | loff_t i_size, pos; | |
887 | ssize_t bytes = 0; | |
888 | int ret; | |
889 | ||
890 | if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) | |
891 | return -EINVAL; | |
892 | ||
39eeb4fb MZ |
893 | ret = security_kernel_read_file(file, id); |
894 | if (ret) | |
895 | return ret; | |
896 | ||
39d637af DK |
897 | ret = deny_write_access(file); |
898 | if (ret) | |
899 | return ret; | |
900 | ||
b44a7dfc | 901 | i_size = i_size_read(file_inode(file)); |
39d637af DK |
902 | if (max_size > 0 && i_size > max_size) { |
903 | ret = -EFBIG; | |
904 | goto out; | |
905 | } | |
906 | if (i_size <= 0) { | |
907 | ret = -EINVAL; | |
908 | goto out; | |
909 | } | |
b44a7dfc | 910 | |
a098ecd2 SB |
911 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) |
912 | *buf = vmalloc(i_size); | |
39d637af DK |
913 | if (!*buf) { |
914 | ret = -ENOMEM; | |
915 | goto out; | |
916 | } | |
b44a7dfc MZ |
917 | |
918 | pos = 0; | |
919 | while (pos < i_size) { | |
920 | bytes = kernel_read(file, pos, (char *)(*buf) + pos, | |
921 | i_size - pos); | |
922 | if (bytes < 0) { | |
923 | ret = bytes; | |
924 | goto out; | |
925 | } | |
926 | ||
927 | if (bytes == 0) | |
928 | break; | |
929 | pos += bytes; | |
930 | } | |
931 | ||
932 | if (pos != i_size) { | |
933 | ret = -EIO; | |
39d637af | 934 | goto out_free; |
b44a7dfc MZ |
935 | } |
936 | ||
bc8ca5b9 | 937 | ret = security_kernel_post_read_file(file, *buf, i_size, id); |
b44a7dfc MZ |
938 | if (!ret) |
939 | *size = pos; | |
940 | ||
39d637af | 941 | out_free: |
b44a7dfc | 942 | if (ret < 0) { |
a098ecd2 SB |
943 | if (id != READING_FIRMWARE_PREALLOC_BUFFER) { |
944 | vfree(*buf); | |
945 | *buf = NULL; | |
946 | } | |
b44a7dfc | 947 | } |
39d637af DK |
948 | |
949 | out: | |
950 | allow_write_access(file); | |
b44a7dfc MZ |
951 | return ret; |
952 | } | |
953 | EXPORT_SYMBOL_GPL(kernel_read_file); | |
954 | ||
09596b94 MZ |
955 | int kernel_read_file_from_path(char *path, void **buf, loff_t *size, |
956 | loff_t max_size, enum kernel_read_file_id id) | |
957 | { | |
958 | struct file *file; | |
959 | int ret; | |
960 | ||
961 | if (!path || !*path) | |
962 | return -EINVAL; | |
963 | ||
964 | file = filp_open(path, O_RDONLY, 0); | |
965 | if (IS_ERR(file)) | |
966 | return PTR_ERR(file); | |
967 | ||
968 | ret = kernel_read_file(file, buf, size, max_size, id); | |
969 | fput(file); | |
970 | return ret; | |
971 | } | |
972 | EXPORT_SYMBOL_GPL(kernel_read_file_from_path); | |
973 | ||
b844f0ec MZ |
974 | int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, |
975 | enum kernel_read_file_id id) | |
976 | { | |
977 | struct fd f = fdget(fd); | |
978 | int ret = -EBADF; | |
979 | ||
980 | if (!f.file) | |
981 | goto out; | |
982 | ||
983 | ret = kernel_read_file(f.file, buf, size, max_size, id); | |
984 | out: | |
985 | fdput(f); | |
986 | return ret; | |
987 | } | |
988 | EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); | |
989 | ||
3dc20cb2 AV |
990 | ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) |
991 | { | |
ec695579 | 992 | ssize_t res = vfs_read(file, (void __user *)addr, len, &pos); |
3dc20cb2 AV |
993 | if (res > 0) |
994 | flush_icache_range(addr, addr + len); | |
995 | return res; | |
996 | } | |
997 | EXPORT_SYMBOL(read_code); | |
998 | ||
1da177e4 LT |
999 | static int exec_mmap(struct mm_struct *mm) |
1000 | { | |
1001 | struct task_struct *tsk; | |
615d6e87 | 1002 | struct mm_struct *old_mm, *active_mm; |
1da177e4 LT |
1003 | |
1004 | /* Notify parent that we're no longer interested in the old VM */ | |
1005 | tsk = current; | |
1006 | old_mm = current->mm; | |
1007 | mm_release(tsk, old_mm); | |
1008 | ||
1009 | if (old_mm) { | |
4fe7efdb | 1010 | sync_mm_rss(old_mm); |
1da177e4 LT |
1011 | /* |
1012 | * Make sure that if there is a core dump in progress | |
1013 | * for the old mm, we get out and die instead of going | |
1014 | * through with the exec. We must hold mmap_sem around | |
999d9fc1 | 1015 | * checking core_state and changing tsk->mm. |
1da177e4 LT |
1016 | */ |
1017 | down_read(&old_mm->mmap_sem); | |
999d9fc1 | 1018 | if (unlikely(old_mm->core_state)) { |
1da177e4 LT |
1019 | up_read(&old_mm->mmap_sem); |
1020 | return -EINTR; | |
1021 | } | |
1022 | } | |
1023 | task_lock(tsk); | |
1024 | active_mm = tsk->active_mm; | |
1025 | tsk->mm = mm; | |
1026 | tsk->active_mm = mm; | |
1027 | activate_mm(active_mm, mm); | |
615d6e87 DB |
1028 | tsk->mm->vmacache_seqnum = 0; |
1029 | vmacache_flush(tsk); | |
1da177e4 | 1030 | task_unlock(tsk); |
1da177e4 LT |
1031 | if (old_mm) { |
1032 | up_read(&old_mm->mmap_sem); | |
7dddb12c | 1033 | BUG_ON(active_mm != old_mm); |
701085b2 | 1034 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
31a78f23 | 1035 | mm_update_next_owner(old_mm); |
1da177e4 LT |
1036 | mmput(old_mm); |
1037 | return 0; | |
1038 | } | |
1039 | mmdrop(active_mm); | |
1040 | return 0; | |
1041 | } | |
1042 | ||
1043 | /* | |
1044 | * This function makes sure the current process has its own signal table, | |
1045 | * so that flush_signal_handlers can later reset the handlers without | |
1046 | * disturbing other processes. (Other processes might share the signal | |
1047 | * table via the CLONE_SIGHAND option to clone().) | |
1048 | */ | |
858119e1 | 1049 | static int de_thread(struct task_struct *tsk) |
1da177e4 LT |
1050 | { |
1051 | struct signal_struct *sig = tsk->signal; | |
b2c903b8 | 1052 | struct sighand_struct *oldsighand = tsk->sighand; |
1da177e4 | 1053 | spinlock_t *lock = &oldsighand->siglock; |
1da177e4 | 1054 | |
aafe6c2a | 1055 | if (thread_group_empty(tsk)) |
1da177e4 LT |
1056 | goto no_thread_group; |
1057 | ||
1058 | /* | |
1059 | * Kill all other threads in the thread group. | |
1da177e4 | 1060 | */ |
1da177e4 | 1061 | spin_lock_irq(lock); |
ed5d2cac | 1062 | if (signal_group_exit(sig)) { |
1da177e4 LT |
1063 | /* |
1064 | * Another group action in progress, just | |
1065 | * return so that the signal is processed. | |
1066 | */ | |
1067 | spin_unlock_irq(lock); | |
1da177e4 LT |
1068 | return -EAGAIN; |
1069 | } | |
d344193a | 1070 | |
ed5d2cac | 1071 | sig->group_exit_task = tsk; |
d344193a ON |
1072 | sig->notify_count = zap_other_threads(tsk); |
1073 | if (!thread_group_leader(tsk)) | |
1074 | sig->notify_count--; | |
1da177e4 | 1075 | |
d344193a | 1076 | while (sig->notify_count) { |
d5bbd43d | 1077 | __set_current_state(TASK_KILLABLE); |
1da177e4 LT |
1078 | spin_unlock_irq(lock); |
1079 | schedule(); | |
d5bbd43d ON |
1080 | if (unlikely(__fatal_signal_pending(tsk))) |
1081 | goto killed; | |
1da177e4 LT |
1082 | spin_lock_irq(lock); |
1083 | } | |
1da177e4 LT |
1084 | spin_unlock_irq(lock); |
1085 | ||
1086 | /* | |
1087 | * At this point all other threads have exited, all we have to | |
1088 | * do is to wait for the thread group leader to become inactive, | |
1089 | * and to assume its PID: | |
1090 | */ | |
aafe6c2a | 1091 | if (!thread_group_leader(tsk)) { |
8187926b | 1092 | struct task_struct *leader = tsk->group_leader; |
6db840fa | 1093 | |
6db840fa | 1094 | for (;;) { |
780de9dd | 1095 | cgroup_threadgroup_change_begin(tsk); |
6db840fa | 1096 | write_lock_irq(&tasklist_lock); |
dfcce791 KT |
1097 | /* |
1098 | * Do this under tasklist_lock to ensure that | |
1099 | * exit_notify() can't miss ->group_exit_task | |
1100 | */ | |
1101 | sig->notify_count = -1; | |
6db840fa ON |
1102 | if (likely(leader->exit_state)) |
1103 | break; | |
d5bbd43d | 1104 | __set_current_state(TASK_KILLABLE); |
6db840fa | 1105 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1106 | cgroup_threadgroup_change_end(tsk); |
6db840fa | 1107 | schedule(); |
d5bbd43d ON |
1108 | if (unlikely(__fatal_signal_pending(tsk))) |
1109 | goto killed; | |
6db840fa | 1110 | } |
1da177e4 | 1111 | |
f5e90281 RM |
1112 | /* |
1113 | * The only record we have of the real-time age of a | |
1114 | * process, regardless of execs it's done, is start_time. | |
1115 | * All the past CPU time is accumulated in signal_struct | |
1116 | * from sister threads now dead. But in this non-leader | |
1117 | * exec, nothing survives from the original leader thread, | |
1118 | * whose birth marks the true age of this process now. | |
1119 | * When we take on its identity by switching to its PID, we | |
1120 | * also take its birthdate (always earlier than our own). | |
1121 | */ | |
aafe6c2a | 1122 | tsk->start_time = leader->start_time; |
266b7a02 | 1123 | tsk->real_start_time = leader->real_start_time; |
f5e90281 | 1124 | |
bac0abd6 PE |
1125 | BUG_ON(!same_thread_group(leader, tsk)); |
1126 | BUG_ON(has_group_leader_pid(tsk)); | |
1da177e4 LT |
1127 | /* |
1128 | * An exec() starts a new thread group with the | |
1129 | * TGID of the previous thread group. Rehash the | |
1130 | * two threads with a switched PID, and release | |
1131 | * the former thread group leader: | |
1132 | */ | |
d73d6529 EB |
1133 | |
1134 | /* Become a process group leader with the old leader's pid. | |
c18258c6 EB |
1135 | * The old leader becomes a thread of the this thread group. |
1136 | * Note: The old leader also uses this pid until release_task | |
d73d6529 EB |
1137 | * is called. Odd but simple and correct. |
1138 | */ | |
aafe6c2a | 1139 | tsk->pid = leader->pid; |
3f418548 | 1140 | change_pid(tsk, PIDTYPE_PID, task_pid(leader)); |
aafe6c2a EB |
1141 | transfer_pid(leader, tsk, PIDTYPE_PGID); |
1142 | transfer_pid(leader, tsk, PIDTYPE_SID); | |
9cd80bbb | 1143 | |
aafe6c2a | 1144 | list_replace_rcu(&leader->tasks, &tsk->tasks); |
9cd80bbb | 1145 | list_replace_init(&leader->sibling, &tsk->sibling); |
1da177e4 | 1146 | |
aafe6c2a EB |
1147 | tsk->group_leader = tsk; |
1148 | leader->group_leader = tsk; | |
de12a787 | 1149 | |
aafe6c2a | 1150 | tsk->exit_signal = SIGCHLD; |
087806b1 | 1151 | leader->exit_signal = -1; |
962b564c ON |
1152 | |
1153 | BUG_ON(leader->exit_state != EXIT_ZOMBIE); | |
1154 | leader->exit_state = EXIT_DEAD; | |
eac1b5e5 ON |
1155 | |
1156 | /* | |
1157 | * We are going to release_task()->ptrace_unlink() silently, | |
1158 | * the tracer can sleep in do_wait(). EXIT_DEAD guarantees | |
1159 | * the tracer wont't block again waiting for this thread. | |
1160 | */ | |
1161 | if (unlikely(leader->ptrace)) | |
1162 | __wake_up_parent(leader, leader->parent); | |
1da177e4 | 1163 | write_unlock_irq(&tasklist_lock); |
780de9dd | 1164 | cgroup_threadgroup_change_end(tsk); |
8187926b ON |
1165 | |
1166 | release_task(leader); | |
ed5d2cac | 1167 | } |
1da177e4 | 1168 | |
6db840fa ON |
1169 | sig->group_exit_task = NULL; |
1170 | sig->notify_count = 0; | |
1da177e4 LT |
1171 | |
1172 | no_thread_group: | |
e6368253 ON |
1173 | /* we have changed execution domain */ |
1174 | tsk->exit_signal = SIGCHLD; | |
1175 | ||
baa73d9e | 1176 | #ifdef CONFIG_POSIX_TIMERS |
1da177e4 | 1177 | exit_itimers(sig); |
cbaffba1 | 1178 | flush_itimer_signals(); |
baa73d9e | 1179 | #endif |
329f7dba | 1180 | |
b2c903b8 ON |
1181 | if (atomic_read(&oldsighand->count) != 1) { |
1182 | struct sighand_struct *newsighand; | |
1da177e4 | 1183 | /* |
b2c903b8 ON |
1184 | * This ->sighand is shared with the CLONE_SIGHAND |
1185 | * but not CLONE_THREAD task, switch to the new one. | |
1da177e4 | 1186 | */ |
b2c903b8 ON |
1187 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
1188 | if (!newsighand) | |
1189 | return -ENOMEM; | |
1190 | ||
1da177e4 LT |
1191 | atomic_set(&newsighand->count, 1); |
1192 | memcpy(newsighand->action, oldsighand->action, | |
1193 | sizeof(newsighand->action)); | |
1194 | ||
1195 | write_lock_irq(&tasklist_lock); | |
1196 | spin_lock(&oldsighand->siglock); | |
aafe6c2a | 1197 | rcu_assign_pointer(tsk->sighand, newsighand); |
1da177e4 LT |
1198 | spin_unlock(&oldsighand->siglock); |
1199 | write_unlock_irq(&tasklist_lock); | |
1200 | ||
fba2afaa | 1201 | __cleanup_sighand(oldsighand); |
1da177e4 LT |
1202 | } |
1203 | ||
aafe6c2a | 1204 | BUG_ON(!thread_group_leader(tsk)); |
1da177e4 | 1205 | return 0; |
d5bbd43d ON |
1206 | |
1207 | killed: | |
1208 | /* protects against exit_notify() and __exit_signal() */ | |
1209 | read_lock(&tasklist_lock); | |
1210 | sig->group_exit_task = NULL; | |
1211 | sig->notify_count = 0; | |
1212 | read_unlock(&tasklist_lock); | |
1213 | return -EAGAIN; | |
1da177e4 | 1214 | } |
0840a90d | 1215 | |
59714d65 | 1216 | char *get_task_comm(char *buf, struct task_struct *tsk) |
1da177e4 LT |
1217 | { |
1218 | /* buf must be at least sizeof(tsk->comm) in size */ | |
1219 | task_lock(tsk); | |
1220 | strncpy(buf, tsk->comm, sizeof(tsk->comm)); | |
1221 | task_unlock(tsk); | |
59714d65 | 1222 | return buf; |
1da177e4 | 1223 | } |
7d74f492 | 1224 | EXPORT_SYMBOL_GPL(get_task_comm); |
1da177e4 | 1225 | |
6a6d27de AV |
1226 | /* |
1227 | * These functions flushes out all traces of the currently running executable | |
1228 | * so that a new one can be started | |
1229 | */ | |
1230 | ||
82b89778 | 1231 | void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) |
1da177e4 LT |
1232 | { |
1233 | task_lock(tsk); | |
43d2b113 | 1234 | trace_task_rename(tsk, buf); |
1da177e4 LT |
1235 | strlcpy(tsk->comm, buf, sizeof(tsk->comm)); |
1236 | task_unlock(tsk); | |
82b89778 | 1237 | perf_event_comm(tsk, exec); |
1da177e4 LT |
1238 | } |
1239 | ||
1240 | int flush_old_exec(struct linux_binprm * bprm) | |
1241 | { | |
221af7f8 | 1242 | int retval; |
1da177e4 LT |
1243 | |
1244 | /* | |
1245 | * Make sure we have a private signal table and that | |
1246 | * we are unassociated from the previous thread group. | |
1247 | */ | |
1248 | retval = de_thread(current); | |
1249 | if (retval) | |
1250 | goto out; | |
1251 | ||
6e399cd1 DB |
1252 | /* |
1253 | * Must be called _before_ exec_mmap() as bprm->mm is | |
1254 | * not visibile until then. This also enables the update | |
1255 | * to be lockless. | |
1256 | */ | |
925d1c40 | 1257 | set_mm_exe_file(bprm->mm, bprm->file); |
6e399cd1 | 1258 | |
1da177e4 LT |
1259 | /* |
1260 | * Release all of the old mmap stuff | |
1261 | */ | |
3c77f845 | 1262 | acct_arg_size(bprm, 0); |
1da177e4 LT |
1263 | retval = exec_mmap(bprm->mm); |
1264 | if (retval) | |
fd8328be | 1265 | goto out; |
1da177e4 LT |
1266 | |
1267 | bprm->mm = NULL; /* We're using it now */ | |
7ab02af4 | 1268 | |
dac853ae | 1269 | set_fs(USER_DS); |
b88fae64 ZY |
1270 | current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | |
1271 | PF_NOFREEZE | PF_NO_SETAFFINITY); | |
7ab02af4 LT |
1272 | flush_thread(); |
1273 | current->personality &= ~bprm->per_clear; | |
1274 | ||
613cc2b6 AS |
1275 | /* |
1276 | * We have to apply CLOEXEC before we change whether the process is | |
1277 | * dumpable (in setup_new_exec) to avoid a race with a process in userspace | |
1278 | * trying to access the should-be-closed file descriptors of a process | |
1279 | * undergoing exec(2). | |
1280 | */ | |
1281 | do_close_on_exec(current->files); | |
221af7f8 LT |
1282 | return 0; |
1283 | ||
1284 | out: | |
1285 | return retval; | |
1286 | } | |
1287 | EXPORT_SYMBOL(flush_old_exec); | |
1288 | ||
1b5d783c AV |
1289 | void would_dump(struct linux_binprm *bprm, struct file *file) |
1290 | { | |
f84df2a6 EB |
1291 | struct inode *inode = file_inode(file); |
1292 | if (inode_permission(inode, MAY_READ) < 0) { | |
1293 | struct user_namespace *old, *user_ns; | |
1b5d783c | 1294 | bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
f84df2a6 EB |
1295 | |
1296 | /* Ensure mm->user_ns contains the executable */ | |
1297 | user_ns = old = bprm->mm->user_ns; | |
1298 | while ((user_ns != &init_user_ns) && | |
1299 | !privileged_wrt_inode_uidgid(user_ns, inode)) | |
1300 | user_ns = user_ns->parent; | |
1301 | ||
1302 | if (old != user_ns) { | |
1303 | bprm->mm->user_ns = get_user_ns(user_ns); | |
1304 | put_user_ns(old); | |
1305 | } | |
1306 | } | |
1b5d783c AV |
1307 | } |
1308 | EXPORT_SYMBOL(would_dump); | |
1309 | ||
221af7f8 LT |
1310 | void setup_new_exec(struct linux_binprm * bprm) |
1311 | { | |
221af7f8 | 1312 | arch_pick_mmap_layout(current->mm); |
1da177e4 LT |
1313 | |
1314 | /* This is the point of no return */ | |
1da177e4 LT |
1315 | current->sas_ss_sp = current->sas_ss_size = 0; |
1316 | ||
8e96e3b7 | 1317 | if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) |
e579d2c2 | 1318 | set_dumpable(current->mm, SUID_DUMP_USER); |
d6e71144 | 1319 | else |
6c5d5238 | 1320 | set_dumpable(current->mm, suid_dumpable); |
d6e71144 | 1321 | |
e041e328 | 1322 | perf_event_exec(); |
82b89778 | 1323 | __set_task_comm(current, kbasename(bprm->filename), true); |
1da177e4 | 1324 | |
0551fbd2 BH |
1325 | /* Set the new mm task size. We have to do that late because it may |
1326 | * depend on TIF_32BIT which is only updated in flush_thread() on | |
1327 | * some architectures like powerpc | |
1328 | */ | |
1329 | current->mm->task_size = TASK_SIZE; | |
1330 | ||
a6f76f23 | 1331 | /* install the new credentials */ |
8e96e3b7 EB |
1332 | if (!uid_eq(bprm->cred->uid, current_euid()) || |
1333 | !gid_eq(bprm->cred->gid, current_egid())) { | |
d2d56c5f | 1334 | current->pdeath_signal = 0; |
1b5d783c | 1335 | } else { |
1b5d783c AV |
1336 | if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) |
1337 | set_dumpable(current->mm, suid_dumpable); | |
1da177e4 LT |
1338 | } |
1339 | ||
1340 | /* An exec changes our domain. We are no longer part of the thread | |
1341 | group */ | |
1da177e4 | 1342 | current->self_exec_id++; |
1da177e4 | 1343 | flush_signal_handlers(current, 0); |
1da177e4 | 1344 | } |
221af7f8 | 1345 | EXPORT_SYMBOL(setup_new_exec); |
1da177e4 | 1346 | |
a2a8474c ON |
1347 | /* |
1348 | * Prepare credentials and lock ->cred_guard_mutex. | |
1349 | * install_exec_creds() commits the new creds and drops the lock. | |
1350 | * Or, if exec fails before, free_bprm() should release ->cred and | |
1351 | * and unlock. | |
1352 | */ | |
1353 | int prepare_bprm_creds(struct linux_binprm *bprm) | |
1354 | { | |
9b1bf12d | 1355 | if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
a2a8474c ON |
1356 | return -ERESTARTNOINTR; |
1357 | ||
1358 | bprm->cred = prepare_exec_creds(); | |
1359 | if (likely(bprm->cred)) | |
1360 | return 0; | |
1361 | ||
9b1bf12d | 1362 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1363 | return -ENOMEM; |
1364 | } | |
1365 | ||
c4ad8f98 | 1366 | static void free_bprm(struct linux_binprm *bprm) |
a2a8474c ON |
1367 | { |
1368 | free_arg_pages(bprm); | |
1369 | if (bprm->cred) { | |
9b1bf12d | 1370 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a2a8474c ON |
1371 | abort_creds(bprm->cred); |
1372 | } | |
63e46b95 ON |
1373 | if (bprm->file) { |
1374 | allow_write_access(bprm->file); | |
1375 | fput(bprm->file); | |
1376 | } | |
b66c5984 KC |
1377 | /* If a binfmt changed the interp, free it. */ |
1378 | if (bprm->interp != bprm->filename) | |
1379 | kfree(bprm->interp); | |
a2a8474c ON |
1380 | kfree(bprm); |
1381 | } | |
1382 | ||
b66c5984 KC |
1383 | int bprm_change_interp(char *interp, struct linux_binprm *bprm) |
1384 | { | |
1385 | /* If a binfmt changed the interp, free it first. */ | |
1386 | if (bprm->interp != bprm->filename) | |
1387 | kfree(bprm->interp); | |
1388 | bprm->interp = kstrdup(interp, GFP_KERNEL); | |
1389 | if (!bprm->interp) | |
1390 | return -ENOMEM; | |
1391 | return 0; | |
1392 | } | |
1393 | EXPORT_SYMBOL(bprm_change_interp); | |
1394 | ||
a6f76f23 DH |
1395 | /* |
1396 | * install the new credentials for this executable | |
1397 | */ | |
1398 | void install_exec_creds(struct linux_binprm *bprm) | |
1399 | { | |
1400 | security_bprm_committing_creds(bprm); | |
1401 | ||
1402 | commit_creds(bprm->cred); | |
1403 | bprm->cred = NULL; | |
2976b10f SE |
1404 | |
1405 | /* | |
1406 | * Disable monitoring for regular users | |
1407 | * when executing setuid binaries. Must | |
1408 | * wait until new credentials are committed | |
1409 | * by commit_creds() above | |
1410 | */ | |
1411 | if (get_dumpable(current->mm) != SUID_DUMP_USER) | |
1412 | perf_event_exit_task(current); | |
a2a8474c ON |
1413 | /* |
1414 | * cred_guard_mutex must be held at least to this point to prevent | |
a6f76f23 | 1415 | * ptrace_attach() from altering our determination of the task's |
a2a8474c ON |
1416 | * credentials; any time after this it may be unlocked. |
1417 | */ | |
a6f76f23 | 1418 | security_bprm_committed_creds(bprm); |
9b1bf12d | 1419 | mutex_unlock(¤t->signal->cred_guard_mutex); |
a6f76f23 DH |
1420 | } |
1421 | EXPORT_SYMBOL(install_exec_creds); | |
1422 | ||
1423 | /* | |
1424 | * determine how safe it is to execute the proposed program | |
9b1bf12d | 1425 | * - the caller must hold ->cred_guard_mutex to protect against |
c2e1f2e3 | 1426 | * PTRACE_ATTACH or seccomp thread-sync |
a6f76f23 | 1427 | */ |
9e00cdb0 | 1428 | static void check_unsafe_exec(struct linux_binprm *bprm) |
a6f76f23 | 1429 | { |
0bf2f3ae | 1430 | struct task_struct *p = current, *t; |
f1191b50 | 1431 | unsigned n_fs; |
a6f76f23 | 1432 | |
9227dd2a EB |
1433 | if (p->ptrace) |
1434 | bprm->unsafe |= LSM_UNSAFE_PTRACE; | |
a6f76f23 | 1435 | |
259e5e6c AL |
1436 | /* |
1437 | * This isn't strictly necessary, but it makes it harder for LSMs to | |
1438 | * mess up. | |
1439 | */ | |
1d4457f9 | 1440 | if (task_no_new_privs(current)) |
259e5e6c AL |
1441 | bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
1442 | ||
83f62a2e | 1443 | t = p; |
0bf2f3ae | 1444 | n_fs = 1; |
2a4419b5 | 1445 | spin_lock(&p->fs->lock); |
437f7fdb | 1446 | rcu_read_lock(); |
83f62a2e | 1447 | while_each_thread(p, t) { |
0bf2f3ae DH |
1448 | if (t->fs == p->fs) |
1449 | n_fs++; | |
0bf2f3ae | 1450 | } |
437f7fdb | 1451 | rcu_read_unlock(); |
0bf2f3ae | 1452 | |
9e00cdb0 | 1453 | if (p->fs->users > n_fs) |
a6f76f23 | 1454 | bprm->unsafe |= LSM_UNSAFE_SHARE; |
9e00cdb0 ON |
1455 | else |
1456 | p->fs->in_exec = 1; | |
2a4419b5 | 1457 | spin_unlock(&p->fs->lock); |
a6f76f23 DH |
1458 | } |
1459 | ||
8b01fc86 JH |
1460 | static void bprm_fill_uid(struct linux_binprm *bprm) |
1461 | { | |
1462 | struct inode *inode; | |
1463 | unsigned int mode; | |
1464 | kuid_t uid; | |
1465 | kgid_t gid; | |
1466 | ||
cb6fd68f KC |
1467 | /* |
1468 | * Since this can be called multiple times (via prepare_binprm), | |
1469 | * we must clear any previous work done when setting set[ug]id | |
1470 | * bits from any earlier bprm->file uses (for example when run | |
1471 | * first for a setuid script then again for its interpreter). | |
1472 | */ | |
8b01fc86 JH |
1473 | bprm->cred->euid = current_euid(); |
1474 | bprm->cred->egid = current_egid(); | |
1475 | ||
380cf5ba | 1476 | if (!mnt_may_suid(bprm->file->f_path.mnt)) |
8b01fc86 JH |
1477 | return; |
1478 | ||
1479 | if (task_no_new_privs(current)) | |
1480 | return; | |
1481 | ||
fea6d2a6 | 1482 | inode = bprm->file->f_path.dentry->d_inode; |
8b01fc86 JH |
1483 | mode = READ_ONCE(inode->i_mode); |
1484 | if (!(mode & (S_ISUID|S_ISGID))) | |
1485 | return; | |
1486 | ||
1487 | /* Be careful if suid/sgid is set */ | |
5955102c | 1488 | inode_lock(inode); |
8b01fc86 JH |
1489 | |
1490 | /* reload atomically mode/uid/gid now that lock held */ | |
1491 | mode = inode->i_mode; | |
1492 | uid = inode->i_uid; | |
1493 | gid = inode->i_gid; | |
5955102c | 1494 | inode_unlock(inode); |
8b01fc86 JH |
1495 | |
1496 | /* We ignore suid/sgid if there are no mappings for them in the ns */ | |
1497 | if (!kuid_has_mapping(bprm->cred->user_ns, uid) || | |
1498 | !kgid_has_mapping(bprm->cred->user_ns, gid)) | |
1499 | return; | |
1500 | ||
1501 | if (mode & S_ISUID) { | |
1502 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1503 | bprm->cred->euid = uid; | |
1504 | } | |
1505 | ||
1506 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { | |
1507 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
1508 | bprm->cred->egid = gid; | |
1509 | } | |
1510 | } | |
1511 | ||
9e00cdb0 ON |
1512 | /* |
1513 | * Fill the binprm structure from the inode. | |
1da177e4 | 1514 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
a6f76f23 DH |
1515 | * |
1516 | * This may be called multiple times for binary chains (scripts for example). | |
1da177e4 LT |
1517 | */ |
1518 | int prepare_binprm(struct linux_binprm *bprm) | |
1519 | { | |
1da177e4 LT |
1520 | int retval; |
1521 | ||
8b01fc86 | 1522 | bprm_fill_uid(bprm); |
1da177e4 LT |
1523 | |
1524 | /* fill in binprm security blob */ | |
a6f76f23 | 1525 | retval = security_bprm_set_creds(bprm); |
1da177e4 LT |
1526 | if (retval) |
1527 | return retval; | |
a6f76f23 | 1528 | bprm->cred_prepared = 1; |
1da177e4 | 1529 | |
a6f76f23 DH |
1530 | memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
1531 | return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); | |
1da177e4 LT |
1532 | } |
1533 | ||
1534 | EXPORT_SYMBOL(prepare_binprm); | |
1535 | ||
4fc75ff4 NP |
1536 | /* |
1537 | * Arguments are '\0' separated strings found at the location bprm->p | |
1538 | * points to; chop off the first by relocating brpm->p to right after | |
1539 | * the first '\0' encountered. | |
1540 | */ | |
b6a2fea3 | 1541 | int remove_arg_zero(struct linux_binprm *bprm) |
1da177e4 | 1542 | { |
b6a2fea3 OW |
1543 | int ret = 0; |
1544 | unsigned long offset; | |
1545 | char *kaddr; | |
1546 | struct page *page; | |
4fc75ff4 | 1547 | |
b6a2fea3 OW |
1548 | if (!bprm->argc) |
1549 | return 0; | |
1da177e4 | 1550 | |
b6a2fea3 OW |
1551 | do { |
1552 | offset = bprm->p & ~PAGE_MASK; | |
1553 | page = get_arg_page(bprm, bprm->p, 0); | |
1554 | if (!page) { | |
1555 | ret = -EFAULT; | |
1556 | goto out; | |
1557 | } | |
e8e3c3d6 | 1558 | kaddr = kmap_atomic(page); |
4fc75ff4 | 1559 | |
b6a2fea3 OW |
1560 | for (; offset < PAGE_SIZE && kaddr[offset]; |
1561 | offset++, bprm->p++) | |
1562 | ; | |
4fc75ff4 | 1563 | |
e8e3c3d6 | 1564 | kunmap_atomic(kaddr); |
b6a2fea3 | 1565 | put_arg_page(page); |
b6a2fea3 | 1566 | } while (offset == PAGE_SIZE); |
4fc75ff4 | 1567 | |
b6a2fea3 OW |
1568 | bprm->p++; |
1569 | bprm->argc--; | |
1570 | ret = 0; | |
4fc75ff4 | 1571 | |
b6a2fea3 OW |
1572 | out: |
1573 | return ret; | |
1da177e4 | 1574 | } |
1da177e4 LT |
1575 | EXPORT_SYMBOL(remove_arg_zero); |
1576 | ||
cb7b6b1c | 1577 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
1da177e4 LT |
1578 | /* |
1579 | * cycle the list of binary formats handler, until one recognizes the image | |
1580 | */ | |
3c456bfc | 1581 | int search_binary_handler(struct linux_binprm *bprm) |
1da177e4 | 1582 | { |
cb7b6b1c | 1583 | bool need_retry = IS_ENABLED(CONFIG_MODULES); |
1da177e4 | 1584 | struct linux_binfmt *fmt; |
cb7b6b1c | 1585 | int retval; |
1da177e4 | 1586 | |
d7402698 | 1587 | /* This allows 4 levels of binfmt rewrites before failing hard. */ |
131b2f9f | 1588 | if (bprm->recursion_depth > 5) |
d7402698 KC |
1589 | return -ELOOP; |
1590 | ||
1da177e4 LT |
1591 | retval = security_bprm_check(bprm); |
1592 | if (retval) | |
1593 | return retval; | |
1594 | ||
1da177e4 | 1595 | retval = -ENOENT; |
cb7b6b1c ON |
1596 | retry: |
1597 | read_lock(&binfmt_lock); | |
1598 | list_for_each_entry(fmt, &formats, lh) { | |
1599 | if (!try_module_get(fmt->module)) | |
1600 | continue; | |
1601 | read_unlock(&binfmt_lock); | |
1602 | bprm->recursion_depth++; | |
1603 | retval = fmt->load_binary(bprm); | |
19d860a1 AV |
1604 | read_lock(&binfmt_lock); |
1605 | put_binfmt(fmt); | |
cb7b6b1c | 1606 | bprm->recursion_depth--; |
19d860a1 AV |
1607 | if (retval < 0 && !bprm->mm) { |
1608 | /* we got to flush_old_exec() and failed after it */ | |
1609 | read_unlock(&binfmt_lock); | |
1610 | force_sigsegv(SIGSEGV, current); | |
1611 | return retval; | |
1612 | } | |
1613 | if (retval != -ENOEXEC || !bprm->file) { | |
1614 | read_unlock(&binfmt_lock); | |
cb7b6b1c | 1615 | return retval; |
1da177e4 | 1616 | } |
1da177e4 | 1617 | } |
cb7b6b1c ON |
1618 | read_unlock(&binfmt_lock); |
1619 | ||
19d860a1 | 1620 | if (need_retry) { |
cb7b6b1c ON |
1621 | if (printable(bprm->buf[0]) && printable(bprm->buf[1]) && |
1622 | printable(bprm->buf[2]) && printable(bprm->buf[3])) | |
1623 | return retval; | |
4e0621a0 ON |
1624 | if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0) |
1625 | return retval; | |
cb7b6b1c ON |
1626 | need_retry = false; |
1627 | goto retry; | |
1628 | } | |
1629 | ||
1da177e4 LT |
1630 | return retval; |
1631 | } | |
1da177e4 LT |
1632 | EXPORT_SYMBOL(search_binary_handler); |
1633 | ||
5d1baf3b ON |
1634 | static int exec_binprm(struct linux_binprm *bprm) |
1635 | { | |
1636 | pid_t old_pid, old_vpid; | |
1637 | int ret; | |
1638 | ||
1639 | /* Need to fetch pid before load_binary changes it */ | |
1640 | old_pid = current->pid; | |
1641 | rcu_read_lock(); | |
1642 | old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); | |
1643 | rcu_read_unlock(); | |
1644 | ||
1645 | ret = search_binary_handler(bprm); | |
1646 | if (ret >= 0) { | |
3eaded86 | 1647 | audit_bprm(bprm); |
5d1baf3b ON |
1648 | trace_sched_process_exec(current, old_pid, bprm); |
1649 | ptrace_event(PTRACE_EVENT_EXEC, old_vpid); | |
9beb266f | 1650 | proc_exec_connector(current); |
5d1baf3b ON |
1651 | } |
1652 | ||
1653 | return ret; | |
1654 | } | |
1655 | ||
1da177e4 LT |
1656 | /* |
1657 | * sys_execve() executes a new program. | |
1658 | */ | |
51f39a1f DD |
1659 | static int do_execveat_common(int fd, struct filename *filename, |
1660 | struct user_arg_ptr argv, | |
1661 | struct user_arg_ptr envp, | |
1662 | int flags) | |
1da177e4 | 1663 | { |
51f39a1f | 1664 | char *pathbuf = NULL; |
1da177e4 LT |
1665 | struct linux_binprm *bprm; |
1666 | struct file *file; | |
3b125388 | 1667 | struct files_struct *displaced; |
1da177e4 | 1668 | int retval; |
72fa5997 | 1669 | |
c4ad8f98 LT |
1670 | if (IS_ERR(filename)) |
1671 | return PTR_ERR(filename); | |
1672 | ||
72fa5997 VK |
1673 | /* |
1674 | * We move the actual failure in case of RLIMIT_NPROC excess from | |
1675 | * set*uid() to execve() because too many poorly written programs | |
1676 | * don't check setuid() return code. Here we additionally recheck | |
1677 | * whether NPROC limit is still exceeded. | |
1678 | */ | |
1679 | if ((current->flags & PF_NPROC_EXCEEDED) && | |
bd9d43f4 | 1680 | atomic_read(¤t_user()->processes) > rlimit(RLIMIT_NPROC)) { |
72fa5997 VK |
1681 | retval = -EAGAIN; |
1682 | goto out_ret; | |
1683 | } | |
1684 | ||
1685 | /* We're below the limit (still or again), so we don't want to make | |
1686 | * further execve() calls fail. */ | |
1687 | current->flags &= ~PF_NPROC_EXCEEDED; | |
1da177e4 | 1688 | |
3b125388 | 1689 | retval = unshare_files(&displaced); |
fd8328be AV |
1690 | if (retval) |
1691 | goto out_ret; | |
1692 | ||
1da177e4 | 1693 | retval = -ENOMEM; |
11b0b5ab | 1694 | bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
1da177e4 | 1695 | if (!bprm) |
fd8328be | 1696 | goto out_files; |
1da177e4 | 1697 | |
a2a8474c ON |
1698 | retval = prepare_bprm_creds(bprm); |
1699 | if (retval) | |
a6f76f23 | 1700 | goto out_free; |
498052bb | 1701 | |
9e00cdb0 | 1702 | check_unsafe_exec(bprm); |
a2a8474c | 1703 | current->in_execve = 1; |
a6f76f23 | 1704 | |
51f39a1f | 1705 | file = do_open_execat(fd, filename, flags); |
1da177e4 LT |
1706 | retval = PTR_ERR(file); |
1707 | if (IS_ERR(file)) | |
498052bb | 1708 | goto out_unmark; |
1da177e4 LT |
1709 | |
1710 | sched_exec(); | |
1711 | ||
1da177e4 | 1712 | bprm->file = file; |
51f39a1f DD |
1713 | if (fd == AT_FDCWD || filename->name[0] == '/') { |
1714 | bprm->filename = filename->name; | |
1715 | } else { | |
1716 | if (filename->name[0] == '\0') | |
1717 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd); | |
1718 | else | |
1719 | pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s", | |
1720 | fd, filename->name); | |
1721 | if (!pathbuf) { | |
1722 | retval = -ENOMEM; | |
1723 | goto out_unmark; | |
1724 | } | |
1725 | /* | |
1726 | * Record that a name derived from an O_CLOEXEC fd will be | |
1727 | * inaccessible after exec. Relies on having exclusive access to | |
1728 | * current->files (due to unshare_files above). | |
1729 | */ | |
1730 | if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) | |
1731 | bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; | |
1732 | bprm->filename = pathbuf; | |
1733 | } | |
1734 | bprm->interp = bprm->filename; | |
1da177e4 | 1735 | |
b6a2fea3 OW |
1736 | retval = bprm_mm_init(bprm); |
1737 | if (retval) | |
63e46b95 | 1738 | goto out_unmark; |
1da177e4 | 1739 | |
b6a2fea3 | 1740 | bprm->argc = count(argv, MAX_ARG_STRINGS); |
1da177e4 | 1741 | if ((retval = bprm->argc) < 0) |
a6f76f23 | 1742 | goto out; |
1da177e4 | 1743 | |
b6a2fea3 | 1744 | bprm->envc = count(envp, MAX_ARG_STRINGS); |
1da177e4 | 1745 | if ((retval = bprm->envc) < 0) |
1da177e4 LT |
1746 | goto out; |
1747 | ||
1748 | retval = prepare_binprm(bprm); | |
1749 | if (retval < 0) | |
1750 | goto out; | |
1751 | ||
1752 | retval = copy_strings_kernel(1, &bprm->filename, bprm); | |
1753 | if (retval < 0) | |
1754 | goto out; | |
1755 | ||
1756 | bprm->exec = bprm->p; | |
1757 | retval = copy_strings(bprm->envc, envp, bprm); | |
1758 | if (retval < 0) | |
1759 | goto out; | |
1760 | ||
1761 | retval = copy_strings(bprm->argc, argv, bprm); | |
1762 | if (retval < 0) | |
1763 | goto out; | |
1764 | ||
f84df2a6 EB |
1765 | would_dump(bprm, bprm->file); |
1766 | ||
5d1baf3b | 1767 | retval = exec_binprm(bprm); |
a6f76f23 DH |
1768 | if (retval < 0) |
1769 | goto out; | |
1da177e4 | 1770 | |
a6f76f23 | 1771 | /* execve succeeded */ |
498052bb | 1772 | current->fs->in_exec = 0; |
f9ce1f1c | 1773 | current->in_execve = 0; |
a6f76f23 | 1774 | acct_update_integrals(current); |
82727018 | 1775 | task_numa_free(current); |
a6f76f23 | 1776 | free_bprm(bprm); |
51f39a1f | 1777 | kfree(pathbuf); |
c4ad8f98 | 1778 | putname(filename); |
a6f76f23 DH |
1779 | if (displaced) |
1780 | put_files_struct(displaced); | |
1781 | return retval; | |
1da177e4 | 1782 | |
a6f76f23 | 1783 | out: |
3c77f845 ON |
1784 | if (bprm->mm) { |
1785 | acct_arg_size(bprm, 0); | |
1786 | mmput(bprm->mm); | |
1787 | } | |
1da177e4 | 1788 | |
498052bb | 1789 | out_unmark: |
9e00cdb0 | 1790 | current->fs->in_exec = 0; |
f9ce1f1c | 1791 | current->in_execve = 0; |
a6f76f23 DH |
1792 | |
1793 | out_free: | |
08a6fac1 | 1794 | free_bprm(bprm); |
51f39a1f | 1795 | kfree(pathbuf); |
1da177e4 | 1796 | |
fd8328be | 1797 | out_files: |
3b125388 AV |
1798 | if (displaced) |
1799 | reset_files_struct(displaced); | |
1da177e4 | 1800 | out_ret: |
c4ad8f98 | 1801 | putname(filename); |
1da177e4 LT |
1802 | return retval; |
1803 | } | |
1804 | ||
c4ad8f98 | 1805 | int do_execve(struct filename *filename, |
ba2d0162 | 1806 | const char __user *const __user *__argv, |
da3d4c5f | 1807 | const char __user *const __user *__envp) |
ba2d0162 | 1808 | { |
0e028465 ON |
1809 | struct user_arg_ptr argv = { .ptr.native = __argv }; |
1810 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
51f39a1f DD |
1811 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1812 | } | |
1813 | ||
1814 | int do_execveat(int fd, struct filename *filename, | |
1815 | const char __user *const __user *__argv, | |
1816 | const char __user *const __user *__envp, | |
1817 | int flags) | |
1818 | { | |
1819 | struct user_arg_ptr argv = { .ptr.native = __argv }; | |
1820 | struct user_arg_ptr envp = { .ptr.native = __envp }; | |
1821 | ||
1822 | return do_execveat_common(fd, filename, argv, envp, flags); | |
0e028465 ON |
1823 | } |
1824 | ||
1825 | #ifdef CONFIG_COMPAT | |
c4ad8f98 | 1826 | static int compat_do_execve(struct filename *filename, |
38b983b3 | 1827 | const compat_uptr_t __user *__argv, |
d03d26e5 | 1828 | const compat_uptr_t __user *__envp) |
0e028465 ON |
1829 | { |
1830 | struct user_arg_ptr argv = { | |
1831 | .is_compat = true, | |
1832 | .ptr.compat = __argv, | |
1833 | }; | |
1834 | struct user_arg_ptr envp = { | |
1835 | .is_compat = true, | |
1836 | .ptr.compat = __envp, | |
1837 | }; | |
51f39a1f DD |
1838 | return do_execveat_common(AT_FDCWD, filename, argv, envp, 0); |
1839 | } | |
1840 | ||
1841 | static int compat_do_execveat(int fd, struct filename *filename, | |
1842 | const compat_uptr_t __user *__argv, | |
1843 | const compat_uptr_t __user *__envp, | |
1844 | int flags) | |
1845 | { | |
1846 | struct user_arg_ptr argv = { | |
1847 | .is_compat = true, | |
1848 | .ptr.compat = __argv, | |
1849 | }; | |
1850 | struct user_arg_ptr envp = { | |
1851 | .is_compat = true, | |
1852 | .ptr.compat = __envp, | |
1853 | }; | |
1854 | return do_execveat_common(fd, filename, argv, envp, flags); | |
ba2d0162 | 1855 | } |
0e028465 | 1856 | #endif |
ba2d0162 | 1857 | |
964ee7df | 1858 | void set_binfmt(struct linux_binfmt *new) |
1da177e4 | 1859 | { |
801460d0 HS |
1860 | struct mm_struct *mm = current->mm; |
1861 | ||
1862 | if (mm->binfmt) | |
1863 | module_put(mm->binfmt->module); | |
1da177e4 | 1864 | |
801460d0 | 1865 | mm->binfmt = new; |
964ee7df ON |
1866 | if (new) |
1867 | __module_get(new->module); | |
1da177e4 | 1868 | } |
1da177e4 LT |
1869 | EXPORT_SYMBOL(set_binfmt); |
1870 | ||
6c5d5238 | 1871 | /* |
7288e118 | 1872 | * set_dumpable stores three-value SUID_DUMP_* into mm->flags. |
6c5d5238 KH |
1873 | */ |
1874 | void set_dumpable(struct mm_struct *mm, int value) | |
1875 | { | |
abacd2fe ON |
1876 | unsigned long old, new; |
1877 | ||
7288e118 ON |
1878 | if (WARN_ON((unsigned)value > SUID_DUMP_ROOT)) |
1879 | return; | |
1880 | ||
abacd2fe ON |
1881 | do { |
1882 | old = ACCESS_ONCE(mm->flags); | |
7288e118 | 1883 | new = (old & ~MMF_DUMPABLE_MASK) | value; |
abacd2fe | 1884 | } while (cmpxchg(&mm->flags, old, new) != old); |
6c5d5238 | 1885 | } |
6c5d5238 | 1886 | |
38b983b3 AV |
1887 | SYSCALL_DEFINE3(execve, |
1888 | const char __user *, filename, | |
1889 | const char __user *const __user *, argv, | |
1890 | const char __user *const __user *, envp) | |
1891 | { | |
c4ad8f98 | 1892 | return do_execve(getname(filename), argv, envp); |
38b983b3 | 1893 | } |
51f39a1f DD |
1894 | |
1895 | SYSCALL_DEFINE5(execveat, | |
1896 | int, fd, const char __user *, filename, | |
1897 | const char __user *const __user *, argv, | |
1898 | const char __user *const __user *, envp, | |
1899 | int, flags) | |
1900 | { | |
1901 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1902 | ||
1903 | return do_execveat(fd, | |
1904 | getname_flags(filename, lookup_flags, NULL), | |
1905 | argv, envp, flags); | |
1906 | } | |
1907 | ||
38b983b3 | 1908 | #ifdef CONFIG_COMPAT |
625b1d7e HC |
1909 | COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename, |
1910 | const compat_uptr_t __user *, argv, | |
1911 | const compat_uptr_t __user *, envp) | |
38b983b3 | 1912 | { |
c4ad8f98 | 1913 | return compat_do_execve(getname(filename), argv, envp); |
38b983b3 | 1914 | } |
51f39a1f DD |
1915 | |
1916 | COMPAT_SYSCALL_DEFINE5(execveat, int, fd, | |
1917 | const char __user *, filename, | |
1918 | const compat_uptr_t __user *, argv, | |
1919 | const compat_uptr_t __user *, envp, | |
1920 | int, flags) | |
1921 | { | |
1922 | int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; | |
1923 | ||
1924 | return compat_do_execveat(fd, | |
1925 | getname_flags(filename, lookup_flags, NULL), | |
1926 | argv, envp, flags); | |
1927 | } | |
38b983b3 | 1928 | #endif |