Commit | Line | Data |
---|---|---|
e338d263 | 1 | /* Common capabilities, needed by capability.o and root_plug.o |
1da177e4 LT |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2 of the License, or | |
6 | * (at your option) any later version. | |
7 | * | |
8 | */ | |
9 | ||
c59ede7b | 10 | #include <linux/capability.h> |
3fc689e9 | 11 | #include <linux/audit.h> |
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/security.h> | |
16 | #include <linux/file.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/mman.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/swap.h> | |
1da177e4 LT |
21 | #include <linux/skbuff.h> |
22 | #include <linux/netlink.h> | |
23 | #include <linux/ptrace.h> | |
24 | #include <linux/xattr.h> | |
25 | #include <linux/hugetlb.h> | |
b5376771 | 26 | #include <linux/mount.h> |
b460cbc5 | 27 | #include <linux/sched.h> |
3898b1b4 AM |
28 | #include <linux/prctl.h> |
29 | #include <linux/securebits.h> | |
72c2d582 | 30 | |
1da177e4 LT |
31 | int cap_netlink_send(struct sock *sk, struct sk_buff *skb) |
32 | { | |
b6dff3ec | 33 | NETLINK_CB(skb).eff_cap = current_cap(); |
1da177e4 LT |
34 | return 0; |
35 | } | |
36 | ||
c7bdb545 | 37 | int cap_netlink_recv(struct sk_buff *skb, int cap) |
1da177e4 | 38 | { |
c7bdb545 | 39 | if (!cap_raised(NETLINK_CB(skb).eff_cap, cap)) |
1da177e4 LT |
40 | return -EPERM; |
41 | return 0; | |
42 | } | |
43 | ||
44 | EXPORT_SYMBOL(cap_netlink_recv); | |
45 | ||
a6dbb1ef AM |
46 | /* |
47 | * NOTE WELL: cap_capable() cannot be used like the kernel's capable() | |
48 | * function. That is, it has the reverse semantics: cap_capable() | |
49 | * returns 0 when a task has a capability, but the kernel's capable() | |
50 | * returns 1 for this case. | |
51 | */ | |
06112163 | 52 | int cap_capable(struct task_struct *tsk, int cap, int audit) |
1da177e4 LT |
53 | { |
54 | /* Derived from include/linux/sched.h:capable. */ | |
b6dff3ec | 55 | if (cap_raised(tsk->cred->cap_effective, cap)) |
1da177e4 LT |
56 | return 0; |
57 | return -EPERM; | |
58 | } | |
59 | ||
60 | int cap_settime(struct timespec *ts, struct timezone *tz) | |
61 | { | |
62 | if (!capable(CAP_SYS_TIME)) | |
63 | return -EPERM; | |
64 | return 0; | |
65 | } | |
66 | ||
5cd9c58f | 67 | int cap_ptrace_may_access(struct task_struct *child, unsigned int mode) |
1da177e4 LT |
68 | { |
69 | /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */ | |
b6dff3ec DH |
70 | if (cap_issubset(child->cred->cap_permitted, |
71 | current->cred->cap_permitted)) | |
5cd9c58f DH |
72 | return 0; |
73 | if (capable(CAP_SYS_PTRACE)) | |
74 | return 0; | |
75 | return -EPERM; | |
76 | } | |
77 | ||
78 | int cap_ptrace_traceme(struct task_struct *parent) | |
79 | { | |
b6dff3ec DH |
80 | if (cap_issubset(current->cred->cap_permitted, |
81 | parent->cred->cap_permitted)) | |
5cd9c58f DH |
82 | return 0; |
83 | if (has_capability(parent, CAP_SYS_PTRACE)) | |
84 | return 0; | |
85 | return -EPERM; | |
1da177e4 LT |
86 | } |
87 | ||
88 | int cap_capget (struct task_struct *target, kernel_cap_t *effective, | |
89 | kernel_cap_t *inheritable, kernel_cap_t *permitted) | |
90 | { | |
b6dff3ec DH |
91 | struct cred *cred = target->cred; |
92 | ||
1da177e4 | 93 | /* Derived from kernel/capability.c:sys_capget. */ |
b6dff3ec DH |
94 | *effective = cred->cap_effective; |
95 | *inheritable = cred->cap_inheritable; | |
96 | *permitted = cred->cap_permitted; | |
1da177e4 LT |
97 | return 0; |
98 | } | |
99 | ||
72c2d582 AM |
100 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES |
101 | ||
72c2d582 AM |
102 | static inline int cap_inh_is_capped(void) |
103 | { | |
104 | /* | |
a6dbb1ef AM |
105 | * Return 1 if changes to the inheritable set are limited |
106 | * to the old permitted set. That is, if the current task | |
107 | * does *not* possess the CAP_SETPCAP capability. | |
72c2d582 | 108 | */ |
06112163 | 109 | return (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0); |
72c2d582 AM |
110 | } |
111 | ||
1209726c AM |
112 | static inline int cap_limit_ptraced_target(void) { return 1; } |
113 | ||
72c2d582 AM |
114 | #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */ |
115 | ||
72c2d582 | 116 | static inline int cap_inh_is_capped(void) { return 1; } |
1209726c AM |
117 | static inline int cap_limit_ptraced_target(void) |
118 | { | |
119 | return !capable(CAP_SETPCAP); | |
120 | } | |
72c2d582 AM |
121 | |
122 | #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */ | |
123 | ||
15a2460e DH |
124 | int cap_capset_check(const kernel_cap_t *effective, |
125 | const kernel_cap_t *inheritable, | |
126 | const kernel_cap_t *permitted) | |
1da177e4 | 127 | { |
b6dff3ec DH |
128 | const struct cred *cred = current->cred; |
129 | ||
72c2d582 AM |
130 | if (cap_inh_is_capped() |
131 | && !cap_issubset(*inheritable, | |
b6dff3ec DH |
132 | cap_combine(cred->cap_inheritable, |
133 | cred->cap_permitted))) { | |
72c2d582 | 134 | /* incapable of using this inheritable set */ |
1da177e4 LT |
135 | return -EPERM; |
136 | } | |
3b7391de | 137 | if (!cap_issubset(*inheritable, |
b6dff3ec DH |
138 | cap_combine(cred->cap_inheritable, |
139 | cred->cap_bset))) { | |
3b7391de SH |
140 | /* no new pI capabilities outside bounding set */ |
141 | return -EPERM; | |
142 | } | |
1da177e4 LT |
143 | |
144 | /* verify restrictions on target's new Permitted set */ | |
145 | if (!cap_issubset (*permitted, | |
b6dff3ec DH |
146 | cap_combine (cred->cap_permitted, |
147 | cred->cap_permitted))) { | |
1da177e4 LT |
148 | return -EPERM; |
149 | } | |
150 | ||
151 | /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ | |
152 | if (!cap_issubset (*effective, *permitted)) { | |
153 | return -EPERM; | |
154 | } | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
15a2460e DH |
159 | void cap_capset_set(const kernel_cap_t *effective, |
160 | const kernel_cap_t *inheritable, | |
161 | const kernel_cap_t *permitted) | |
1da177e4 | 162 | { |
b6dff3ec DH |
163 | struct cred *cred = current->cred; |
164 | ||
165 | cred->cap_effective = *effective; | |
166 | cred->cap_inheritable = *inheritable; | |
167 | cred->cap_permitted = *permitted; | |
1da177e4 LT |
168 | } |
169 | ||
b5376771 SH |
170 | static inline void bprm_clear_caps(struct linux_binprm *bprm) |
171 | { | |
5459c164 | 172 | cap_clear(bprm->cap_post_exec_permitted); |
b5376771 SH |
173 | bprm->cap_effective = false; |
174 | } | |
175 | ||
176 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES | |
177 | ||
178 | int cap_inode_need_killpriv(struct dentry *dentry) | |
179 | { | |
180 | struct inode *inode = dentry->d_inode; | |
181 | int error; | |
182 | ||
183 | if (!inode->i_op || !inode->i_op->getxattr) | |
184 | return 0; | |
185 | ||
186 | error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0); | |
187 | if (error <= 0) | |
188 | return 0; | |
189 | return 1; | |
190 | } | |
191 | ||
192 | int cap_inode_killpriv(struct dentry *dentry) | |
193 | { | |
194 | struct inode *inode = dentry->d_inode; | |
195 | ||
196 | if (!inode->i_op || !inode->i_op->removexattr) | |
197 | return 0; | |
198 | ||
199 | return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS); | |
200 | } | |
201 | ||
c0b00441 EP |
202 | static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, |
203 | struct linux_binprm *bprm) | |
b5376771 | 204 | { |
c0b00441 EP |
205 | unsigned i; |
206 | int ret = 0; | |
207 | ||
208 | if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) | |
209 | bprm->cap_effective = true; | |
210 | else | |
211 | bprm->cap_effective = false; | |
212 | ||
213 | CAP_FOR_EACH_U32(i) { | |
214 | __u32 permitted = caps->permitted.cap[i]; | |
215 | __u32 inheritable = caps->inheritable.cap[i]; | |
216 | ||
217 | /* | |
218 | * pP' = (X & fP) | (pI & fI) | |
219 | */ | |
220 | bprm->cap_post_exec_permitted.cap[i] = | |
b6dff3ec DH |
221 | (current->cred->cap_bset.cap[i] & permitted) | |
222 | (current->cred->cap_inheritable.cap[i] & inheritable); | |
c0b00441 EP |
223 | |
224 | if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) { | |
225 | /* | |
226 | * insufficient to execute correctly | |
227 | */ | |
228 | ret = -EPERM; | |
229 | } | |
230 | } | |
231 | ||
232 | /* | |
233 | * For legacy apps, with no internal support for recognizing they | |
234 | * do not have enough capabilities, we return an error if they are | |
235 | * missing some "forced" (aka file-permitted) capabilities. | |
236 | */ | |
237 | return bprm->cap_effective ? ret : 0; | |
238 | } | |
239 | ||
240 | int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) | |
241 | { | |
242 | struct inode *inode = dentry->d_inode; | |
b5376771 | 243 | __u32 magic_etc; |
e338d263 | 244 | unsigned tocopy, i; |
c0b00441 EP |
245 | int size; |
246 | struct vfs_cap_data caps; | |
247 | ||
248 | memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); | |
249 | ||
250 | if (!inode || !inode->i_op || !inode->i_op->getxattr) | |
251 | return -ENODATA; | |
252 | ||
253 | size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps, | |
254 | XATTR_CAPS_SZ); | |
255 | if (size == -ENODATA || size == -EOPNOTSUPP) { | |
256 | /* no data, that's ok */ | |
257 | return -ENODATA; | |
258 | } | |
259 | if (size < 0) | |
260 | return size; | |
b5376771 | 261 | |
e338d263 | 262 | if (size < sizeof(magic_etc)) |
b5376771 SH |
263 | return -EINVAL; |
264 | ||
c0b00441 | 265 | cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc); |
b5376771 SH |
266 | |
267 | switch ((magic_etc & VFS_CAP_REVISION_MASK)) { | |
e338d263 AM |
268 | case VFS_CAP_REVISION_1: |
269 | if (size != XATTR_CAPS_SZ_1) | |
270 | return -EINVAL; | |
271 | tocopy = VFS_CAP_U32_1; | |
272 | break; | |
273 | case VFS_CAP_REVISION_2: | |
274 | if (size != XATTR_CAPS_SZ_2) | |
275 | return -EINVAL; | |
276 | tocopy = VFS_CAP_U32_2; | |
277 | break; | |
b5376771 SH |
278 | default: |
279 | return -EINVAL; | |
280 | } | |
e338d263 | 281 | |
5459c164 | 282 | CAP_FOR_EACH_U32(i) { |
c0b00441 EP |
283 | if (i >= tocopy) |
284 | break; | |
285 | cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted); | |
286 | cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable); | |
e338d263 | 287 | } |
c0b00441 | 288 | return 0; |
b5376771 SH |
289 | } |
290 | ||
291 | /* Locate any VFS capabilities: */ | |
292 | static int get_file_caps(struct linux_binprm *bprm) | |
293 | { | |
294 | struct dentry *dentry; | |
295 | int rc = 0; | |
c0b00441 | 296 | struct cpu_vfs_cap_data vcaps; |
b5376771 | 297 | |
3318a386 SH |
298 | bprm_clear_caps(bprm); |
299 | ||
1f29fae2 SH |
300 | if (!file_caps_enabled) |
301 | return 0; | |
302 | ||
3318a386 | 303 | if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) |
b5376771 | 304 | return 0; |
b5376771 SH |
305 | |
306 | dentry = dget(bprm->file->f_dentry); | |
b5376771 | 307 | |
c0b00441 EP |
308 | rc = get_vfs_caps_from_disk(dentry, &vcaps); |
309 | if (rc < 0) { | |
310 | if (rc == -EINVAL) | |
311 | printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n", | |
312 | __func__, rc, bprm->filename); | |
313 | else if (rc == -ENODATA) | |
314 | rc = 0; | |
b5376771 SH |
315 | goto out; |
316 | } | |
b5376771 | 317 | |
c0b00441 | 318 | rc = bprm_caps_from_vfs_caps(&vcaps, bprm); |
b5376771 SH |
319 | |
320 | out: | |
321 | dput(dentry); | |
322 | if (rc) | |
323 | bprm_clear_caps(bprm); | |
324 | ||
325 | return rc; | |
326 | } | |
327 | ||
328 | #else | |
329 | int cap_inode_need_killpriv(struct dentry *dentry) | |
330 | { | |
331 | return 0; | |
332 | } | |
333 | ||
334 | int cap_inode_killpriv(struct dentry *dentry) | |
335 | { | |
336 | return 0; | |
337 | } | |
338 | ||
339 | static inline int get_file_caps(struct linux_binprm *bprm) | |
340 | { | |
341 | bprm_clear_caps(bprm); | |
342 | return 0; | |
343 | } | |
344 | #endif | |
345 | ||
1da177e4 LT |
346 | int cap_bprm_set_security (struct linux_binprm *bprm) |
347 | { | |
b5376771 | 348 | int ret; |
1da177e4 | 349 | |
b5376771 | 350 | ret = get_file_caps(bprm); |
1da177e4 | 351 | |
5459c164 AM |
352 | if (!issecure(SECURE_NOROOT)) { |
353 | /* | |
354 | * To support inheritance of root-permissions and suid-root | |
355 | * executables under compatibility mode, we override the | |
356 | * capability sets for the file. | |
357 | * | |
358 | * If only the real uid is 0, we do not set the effective | |
359 | * bit. | |
360 | */ | |
b103c598 | 361 | if (bprm->e_uid == 0 || current_uid() == 0) { |
5459c164 AM |
362 | /* pP' = (cap_bset & ~0) | (pI & ~0) */ |
363 | bprm->cap_post_exec_permitted = cap_combine( | |
b6dff3ec DH |
364 | current->cred->cap_bset, |
365 | current->cred->cap_inheritable); | |
5459c164 AM |
366 | bprm->cap_effective = (bprm->e_uid == 0); |
367 | ret = 0; | |
1da177e4 | 368 | } |
1da177e4 | 369 | } |
b5376771 SH |
370 | |
371 | return ret; | |
1da177e4 LT |
372 | } |
373 | ||
374 | void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe) | |
375 | { | |
b6dff3ec | 376 | struct cred *cred = current->cred; |
3fc689e9 | 377 | |
b6dff3ec | 378 | if (bprm->e_uid != cred->uid || bprm->e_gid != cred->gid || |
5459c164 | 379 | !cap_issubset(bprm->cap_post_exec_permitted, |
b6dff3ec | 380 | cred->cap_permitted)) { |
6c5d5238 | 381 | set_dumpable(current->mm, suid_dumpable); |
b5376771 | 382 | current->pdeath_signal = 0; |
1da177e4 LT |
383 | |
384 | if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) { | |
385 | if (!capable(CAP_SETUID)) { | |
b6dff3ec DH |
386 | bprm->e_uid = cred->uid; |
387 | bprm->e_gid = cred->gid; | |
1da177e4 | 388 | } |
1209726c | 389 | if (cap_limit_ptraced_target()) { |
5459c164 AM |
390 | bprm->cap_post_exec_permitted = cap_intersect( |
391 | bprm->cap_post_exec_permitted, | |
b6dff3ec | 392 | cred->cap_permitted); |
1da177e4 LT |
393 | } |
394 | } | |
395 | } | |
396 | ||
b6dff3ec DH |
397 | cred->suid = cred->euid = cred->fsuid = bprm->e_uid; |
398 | cred->sgid = cred->egid = cred->fsgid = bprm->e_gid; | |
1da177e4 LT |
399 | |
400 | /* For init, we want to retain the capabilities set | |
401 | * in the init_task struct. Thus we skip the usual | |
402 | * capability rules */ | |
b460cbc5 | 403 | if (!is_global_init(current)) { |
b6dff3ec | 404 | cred->cap_permitted = bprm->cap_post_exec_permitted; |
e338d263 | 405 | if (bprm->cap_effective) |
b6dff3ec | 406 | cred->cap_effective = bprm->cap_post_exec_permitted; |
e338d263 | 407 | else |
b6dff3ec | 408 | cap_clear(cred->cap_effective); |
1da177e4 LT |
409 | } |
410 | ||
3fc689e9 EP |
411 | /* |
412 | * Audit candidate if current->cap_effective is set | |
413 | * | |
414 | * We do not bother to audit if 3 things are true: | |
415 | * 1) cap_effective has all caps | |
416 | * 2) we are root | |
417 | * 3) root is supposed to have all caps (SECURE_NOROOT) | |
418 | * Since this is just a normal root execing a process. | |
419 | * | |
420 | * Number 1 above might fail if you don't have a full bset, but I think | |
421 | * that is interesting information to audit. | |
422 | */ | |
b6dff3ec DH |
423 | if (!cap_isclear(cred->cap_effective)) { |
424 | if (!cap_issubset(CAP_FULL_SET, cred->cap_effective) || | |
425 | (bprm->e_uid != 0) || (cred->uid != 0) || | |
3fc689e9 | 426 | issecure(SECURE_NOROOT)) |
b6dff3ec DH |
427 | audit_log_bprm_fcaps(bprm, &cred->cap_permitted, |
428 | &cred->cap_effective); | |
3fc689e9 | 429 | } |
1da177e4 | 430 | |
b6dff3ec | 431 | cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
1da177e4 LT |
432 | } |
433 | ||
434 | int cap_bprm_secureexec (struct linux_binprm *bprm) | |
435 | { | |
b6dff3ec DH |
436 | const struct cred *cred = current->cred; |
437 | ||
438 | if (cred->uid != 0) { | |
b5376771 SH |
439 | if (bprm->cap_effective) |
440 | return 1; | |
5459c164 | 441 | if (!cap_isclear(bprm->cap_post_exec_permitted)) |
b5376771 SH |
442 | return 1; |
443 | } | |
444 | ||
b6dff3ec DH |
445 | return (cred->euid != cred->uid || |
446 | cred->egid != cred->gid); | |
1da177e4 LT |
447 | } |
448 | ||
8f0cfa52 DH |
449 | int cap_inode_setxattr(struct dentry *dentry, const char *name, |
450 | const void *value, size_t size, int flags) | |
1da177e4 | 451 | { |
b5376771 SH |
452 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
453 | if (!capable(CAP_SETFCAP)) | |
454 | return -EPERM; | |
455 | return 0; | |
456 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
1da177e4 LT |
457 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
458 | !capable(CAP_SYS_ADMIN)) | |
459 | return -EPERM; | |
460 | return 0; | |
461 | } | |
462 | ||
8f0cfa52 | 463 | int cap_inode_removexattr(struct dentry *dentry, const char *name) |
1da177e4 | 464 | { |
b5376771 SH |
465 | if (!strcmp(name, XATTR_NAME_CAPS)) { |
466 | if (!capable(CAP_SETFCAP)) | |
467 | return -EPERM; | |
468 | return 0; | |
469 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
1da177e4 LT |
470 | sizeof(XATTR_SECURITY_PREFIX) - 1) && |
471 | !capable(CAP_SYS_ADMIN)) | |
472 | return -EPERM; | |
473 | return 0; | |
474 | } | |
475 | ||
476 | /* moved from kernel/sys.c. */ | |
477 | /* | |
478 | * cap_emulate_setxuid() fixes the effective / permitted capabilities of | |
479 | * a process after a call to setuid, setreuid, or setresuid. | |
480 | * | |
481 | * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of | |
482 | * {r,e,s}uid != 0, the permitted and effective capabilities are | |
483 | * cleared. | |
484 | * | |
485 | * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective | |
486 | * capabilities of the process are cleared. | |
487 | * | |
488 | * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective | |
489 | * capabilities are set to the permitted capabilities. | |
490 | * | |
491 | * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should | |
492 | * never happen. | |
493 | * | |
494 | * -astor | |
495 | * | |
496 | * cevans - New behaviour, Oct '99 | |
497 | * A process may, via prctl(), elect to keep its capabilities when it | |
498 | * calls setuid() and switches away from uid==0. Both permitted and | |
499 | * effective sets will be retained. | |
500 | * Without this change, it was impossible for a daemon to drop only some | |
501 | * of its privilege. The call to setuid(!=0) would drop all privileges! | |
502 | * Keeping uid 0 is not an option because uid 0 owns too many vital | |
503 | * files.. | |
504 | * Thanks to Olaf Kirch and Peter Benie for spotting this. | |
505 | */ | |
506 | static inline void cap_emulate_setxuid (int old_ruid, int old_euid, | |
507 | int old_suid) | |
508 | { | |
b6dff3ec | 509 | struct cred *cred = current->cred; |
b103c598 | 510 | |
1da177e4 | 511 | if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) && |
b6dff3ec | 512 | (cred->uid != 0 && cred->euid != 0 && cred->suid != 0) && |
3898b1b4 | 513 | !issecure(SECURE_KEEP_CAPS)) { |
b6dff3ec DH |
514 | cap_clear (cred->cap_permitted); |
515 | cap_clear (cred->cap_effective); | |
1da177e4 | 516 | } |
b6dff3ec DH |
517 | if (old_euid == 0 && cred->euid != 0) { |
518 | cap_clear (cred->cap_effective); | |
1da177e4 | 519 | } |
b6dff3ec DH |
520 | if (old_euid != 0 && cred->euid == 0) { |
521 | cred->cap_effective = cred->cap_permitted; | |
1da177e4 LT |
522 | } |
523 | } | |
524 | ||
525 | int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid, | |
526 | int flags) | |
527 | { | |
b6dff3ec DH |
528 | struct cred *cred = current->cred; |
529 | ||
1da177e4 LT |
530 | switch (flags) { |
531 | case LSM_SETID_RE: | |
532 | case LSM_SETID_ID: | |
533 | case LSM_SETID_RES: | |
534 | /* Copied from kernel/sys.c:setreuid/setuid/setresuid. */ | |
535 | if (!issecure (SECURE_NO_SETUID_FIXUP)) { | |
536 | cap_emulate_setxuid (old_ruid, old_euid, old_suid); | |
537 | } | |
538 | break; | |
539 | case LSM_SETID_FS: | |
540 | { | |
541 | uid_t old_fsuid = old_ruid; | |
542 | ||
543 | /* Copied from kernel/sys.c:setfsuid. */ | |
544 | ||
545 | /* | |
546 | * FIXME - is fsuser used for all CAP_FS_MASK capabilities? | |
547 | * if not, we might be a bit too harsh here. | |
548 | */ | |
549 | ||
550 | if (!issecure (SECURE_NO_SETUID_FIXUP)) { | |
b6dff3ec DH |
551 | if (old_fsuid == 0 && cred->fsuid != 0) { |
552 | cred->cap_effective = | |
e338d263 | 553 | cap_drop_fs_set( |
b6dff3ec | 554 | cred->cap_effective); |
1da177e4 | 555 | } |
b6dff3ec DH |
556 | if (old_fsuid != 0 && cred->fsuid == 0) { |
557 | cred->cap_effective = | |
e338d263 | 558 | cap_raise_fs_set( |
b6dff3ec DH |
559 | cred->cap_effective, |
560 | cred->cap_permitted); | |
1da177e4 LT |
561 | } |
562 | } | |
563 | break; | |
564 | } | |
565 | default: | |
566 | return -EINVAL; | |
567 | } | |
568 | ||
569 | return 0; | |
570 | } | |
571 | ||
b5376771 SH |
572 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES |
573 | /* | |
574 | * Rationale: code calling task_setscheduler, task_setioprio, and | |
575 | * task_setnice, assumes that | |
576 | * . if capable(cap_sys_nice), then those actions should be allowed | |
577 | * . if not capable(cap_sys_nice), but acting on your own processes, | |
578 | * then those actions should be allowed | |
579 | * This is insufficient now since you can call code without suid, but | |
580 | * yet with increased caps. | |
581 | * So we check for increased caps on the target process. | |
582 | */ | |
de45e806 | 583 | static int cap_safe_nice(struct task_struct *p) |
b5376771 | 584 | { |
b6dff3ec DH |
585 | if (!cap_issubset(p->cred->cap_permitted, |
586 | current->cred->cap_permitted) && | |
5cd9c58f | 587 | !capable(CAP_SYS_NICE)) |
b5376771 SH |
588 | return -EPERM; |
589 | return 0; | |
590 | } | |
591 | ||
592 | int cap_task_setscheduler (struct task_struct *p, int policy, | |
593 | struct sched_param *lp) | |
594 | { | |
595 | return cap_safe_nice(p); | |
596 | } | |
597 | ||
598 | int cap_task_setioprio (struct task_struct *p, int ioprio) | |
599 | { | |
600 | return cap_safe_nice(p); | |
601 | } | |
602 | ||
603 | int cap_task_setnice (struct task_struct *p, int nice) | |
604 | { | |
605 | return cap_safe_nice(p); | |
606 | } | |
607 | ||
3b7391de SH |
608 | /* |
609 | * called from kernel/sys.c for prctl(PR_CABSET_DROP) | |
610 | * done without task_capability_lock() because it introduces | |
611 | * no new races - i.e. only another task doing capget() on | |
612 | * this task could get inconsistent info. There can be no | |
613 | * racing writer bc a task can only change its own caps. | |
614 | */ | |
3898b1b4 | 615 | static long cap_prctl_drop(unsigned long cap) |
3b7391de SH |
616 | { |
617 | if (!capable(CAP_SETPCAP)) | |
618 | return -EPERM; | |
619 | if (!cap_valid(cap)) | |
620 | return -EINVAL; | |
b6dff3ec | 621 | cap_lower(current->cred->cap_bset, cap); |
3b7391de SH |
622 | return 0; |
623 | } | |
3898b1b4 | 624 | |
b5376771 SH |
625 | #else |
626 | int cap_task_setscheduler (struct task_struct *p, int policy, | |
627 | struct sched_param *lp) | |
628 | { | |
629 | return 0; | |
630 | } | |
631 | int cap_task_setioprio (struct task_struct *p, int ioprio) | |
632 | { | |
633 | return 0; | |
634 | } | |
635 | int cap_task_setnice (struct task_struct *p, int nice) | |
636 | { | |
637 | return 0; | |
638 | } | |
b5376771 SH |
639 | #endif |
640 | ||
3898b1b4 AM |
641 | int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, |
642 | unsigned long arg4, unsigned long arg5, long *rc_p) | |
643 | { | |
86a264ab | 644 | struct cred *cred = current_cred(); |
3898b1b4 AM |
645 | long error = 0; |
646 | ||
647 | switch (option) { | |
648 | case PR_CAPBSET_READ: | |
649 | if (!cap_valid(arg2)) | |
650 | error = -EINVAL; | |
651 | else | |
b6dff3ec | 652 | error = !!cap_raised(cred->cap_bset, arg2); |
3898b1b4 AM |
653 | break; |
654 | #ifdef CONFIG_SECURITY_FILE_CAPABILITIES | |
655 | case PR_CAPBSET_DROP: | |
656 | error = cap_prctl_drop(arg2); | |
657 | break; | |
658 | ||
659 | /* | |
660 | * The next four prctl's remain to assist with transitioning a | |
661 | * system from legacy UID=0 based privilege (when filesystem | |
662 | * capabilities are not in use) to a system using filesystem | |
663 | * capabilities only - as the POSIX.1e draft intended. | |
664 | * | |
665 | * Note: | |
666 | * | |
667 | * PR_SET_SECUREBITS = | |
668 | * issecure_mask(SECURE_KEEP_CAPS_LOCKED) | |
669 | * | issecure_mask(SECURE_NOROOT) | |
670 | * | issecure_mask(SECURE_NOROOT_LOCKED) | |
671 | * | issecure_mask(SECURE_NO_SETUID_FIXUP) | |
672 | * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) | |
673 | * | |
674 | * will ensure that the current process and all of its | |
675 | * children will be locked into a pure | |
676 | * capability-based-privilege environment. | |
677 | */ | |
678 | case PR_SET_SECUREBITS: | |
b6dff3ec DH |
679 | if ((((cred->securebits & SECURE_ALL_LOCKS) >> 1) |
680 | & (cred->securebits ^ arg2)) /*[1]*/ | |
681 | || ((cred->securebits & SECURE_ALL_LOCKS | |
3898b1b4 AM |
682 | & ~arg2)) /*[2]*/ |
683 | || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ | |
06112163 | 684 | || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0)) { /*[4]*/ |
3898b1b4 AM |
685 | /* |
686 | * [1] no changing of bits that are locked | |
687 | * [2] no unlocking of locks | |
688 | * [3] no setting of unsupported bits | |
689 | * [4] doing anything requires privilege (go read about | |
690 | * the "sendmail capabilities bug") | |
691 | */ | |
692 | error = -EPERM; /* cannot change a locked bit */ | |
693 | } else { | |
b6dff3ec | 694 | cred->securebits = arg2; |
3898b1b4 AM |
695 | } |
696 | break; | |
697 | case PR_GET_SECUREBITS: | |
b6dff3ec | 698 | error = cred->securebits; |
3898b1b4 AM |
699 | break; |
700 | ||
701 | #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */ | |
702 | ||
703 | case PR_GET_KEEPCAPS: | |
704 | if (issecure(SECURE_KEEP_CAPS)) | |
705 | error = 1; | |
706 | break; | |
707 | case PR_SET_KEEPCAPS: | |
708 | if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ | |
709 | error = -EINVAL; | |
710 | else if (issecure(SECURE_KEEP_CAPS_LOCKED)) | |
711 | error = -EPERM; | |
712 | else if (arg2) | |
b6dff3ec | 713 | cred->securebits |= issecure_mask(SECURE_KEEP_CAPS); |
3898b1b4 | 714 | else |
b6dff3ec | 715 | cred->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); |
3898b1b4 AM |
716 | break; |
717 | ||
718 | default: | |
719 | /* No functionality available - continue with default */ | |
720 | return 0; | |
721 | } | |
722 | ||
723 | /* Functionality provided */ | |
724 | *rc_p = error; | |
725 | return 1; | |
726 | } | |
727 | ||
1da177e4 LT |
728 | void cap_task_reparent_to_init (struct task_struct *p) |
729 | { | |
b6dff3ec DH |
730 | struct cred *cred = p->cred; |
731 | ||
732 | cap_set_init_eff(cred->cap_effective); | |
733 | cap_clear(cred->cap_inheritable); | |
734 | cap_set_full(cred->cap_permitted); | |
735 | p->cred->securebits = SECUREBITS_DEFAULT; | |
1da177e4 LT |
736 | } |
737 | ||
738 | int cap_syslog (int type) | |
739 | { | |
740 | if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN)) | |
741 | return -EPERM; | |
742 | return 0; | |
743 | } | |
744 | ||
34b4e4aa | 745 | int cap_vm_enough_memory(struct mm_struct *mm, long pages) |
1da177e4 LT |
746 | { |
747 | int cap_sys_admin = 0; | |
748 | ||
06112163 | 749 | if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0) |
1da177e4 | 750 | cap_sys_admin = 1; |
34b4e4aa | 751 | return __vm_enough_memory(mm, pages, cap_sys_admin); |
1da177e4 LT |
752 | } |
753 |