Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Newer
Older
100644 410 lines (355 sloc) 10.967 kB
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
1 /*
2 * linux/kernel/capability.c
3 *
4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
5 *
72c2d58 V3 file capabilities: alter behavior of cap_setpcap
Andrew Morgan authored
6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
8 */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
9
e68b75a @eparis When the capset syscall is used it is not possible for audit to recor…
eparis authored
10 #include <linux/audit.h>
c59ede7 [PATCH] move capable() to capability.h
Randy.Dunlap authored
11 #include <linux/capability.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include <linux/security.h>
15 #include <linux/syscalls.h>
b460cbc pid namespaces: define is_global_init() and is_container_init()
Serge E. Hallyn authored
16 #include <linux/pid_namespace.h>
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
17 #include <linux/user_namespace.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
18 #include <asm/uaccess.h>
19
20 /*
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
21 * Leveraged for setting/resetting capabilities
22 */
23
24 const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
25
26 EXPORT_SYMBOL(__cap_empty_set);
27
1f29fae file capabilities: add no_file_caps switch (v4)
Serge E. Hallyn authored
28 int file_caps_enabled = 1;
29
30 static int __init file_caps_disable(char *str)
31 {
32 file_caps_enabled = 0;
33 return 1;
34 }
35 __setup("no_file_caps", file_caps_disable);
36
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
37 /*
38 * More recent versions of libcap are available from:
39 *
40 * http://www.kernel.org/pub/linux/libs/security/linux-privs/
41 */
42
43 static void warn_legacy_capability_use(void)
44 {
45 static int warned;
46 if (!warned) {
47 char name[sizeof(current->comm)];
48
49 printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
50 " (legacy support in use)\n",
51 get_task_comm(name, current));
52 warned = 1;
53 }
54 }
55
56 /*
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
57 * Version 2 capabilities worked fine, but the linux/capability.h file
58 * that accompanied their introduction encouraged their use without
59 * the necessary user-space source code changes. As such, we have
60 * created a version 3 with equivalent functionality to version 2, but
61 * with a header change to protect legacy source code from using
62 * version 2 when it wanted to use version 1. If your system has code
63 * that trips the following warning, it is using version 2 specific
64 * capabilities and may be doing so insecurely.
65 *
66 * The remedy is to either upgrade your version of libcap (to 2.10+,
67 * if the application is linked against it), or recompile your
68 * application with modern kernel headers and this warning will go
69 * away.
70 */
71
72 static void warn_deprecated_v2(void)
73 {
74 static int warned;
75
76 if (!warned) {
77 char name[sizeof(current->comm)];
78
79 printk(KERN_INFO "warning: `%s' uses deprecated v2"
80 " capabilities in a way that may be insecure.\n",
81 get_task_comm(name, current));
82 warned = 1;
83 }
84 }
85
86 /*
87 * Version check. Return the number of u32s in each capability flag
88 * array, or a negative value on error.
89 */
90 static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
91 {
92 __u32 version;
93
94 if (get_user(version, &header->version))
95 return -EFAULT;
96
97 switch (version) {
98 case _LINUX_CAPABILITY_VERSION_1:
99 warn_legacy_capability_use();
100 *tocopy = _LINUX_CAPABILITY_U32S_1;
101 break;
102 case _LINUX_CAPABILITY_VERSION_2:
103 warn_deprecated_v2();
104 /*
105 * fall through - v3 is otherwise equivalent to v2.
106 */
107 case _LINUX_CAPABILITY_VERSION_3:
108 *tocopy = _LINUX_CAPABILITY_U32S_3;
109 break;
110 default:
111 if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
112 return -EFAULT;
113 return -EINVAL;
114 }
115
116 return 0;
117 }
118
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
119 /*
d84f4f9 CRED: Inaugurate COW credentials
David Howells authored
120 * The only thing that can change the capabilities of the current
121 * process is the current process. As such, we can't be in this code
122 * at the same time as we are in the process of setting capabilities
123 * in this process. The net result is that we can limit our use of
124 * locks to when we are reading the caps of another process.
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
125 */
126 static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
127 kernel_cap_t *pIp, kernel_cap_t *pPp)
128 {
129 int ret;
130
131 if (pid && (pid != task_pid_vnr(current))) {
132 struct task_struct *target;
133
86fc80f capabilities: Use RCU to protect task lookup in sys_capget
Thomas Gleixner authored
134 rcu_read_lock();
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
135
136 target = find_task_by_vpid(pid);
137 if (!target)
138 ret = -ESRCH;
139 else
140 ret = security_capget(target, pEp, pIp, pPp);
141
86fc80f capabilities: Use RCU to protect task lookup in sys_capget
Thomas Gleixner authored
142 rcu_read_unlock();
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
143 } else
144 ret = security_capget(current, pEp, pIp, pPp);
145
146 return ret;
147 }
148
207a7ba [PATCH] kernel/capability.c: add kerneldoc
Randy Dunlap authored
149 /**
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
150 * sys_capget - get the capabilities of a given process.
207a7ba [PATCH] kernel/capability.c: add kerneldoc
Randy Dunlap authored
151 * @header: pointer to struct that contains capability version and
152 * target pid data
153 * @dataptr: pointer to struct that contains the effective, permitted,
154 * and inheritable capabilities that are returned
155 *
156 * Returns 0 on success and < 0 on error.
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
157 */
b290ebe [CVE-2009-0029] System call wrappers part 04
Heiko Carstens authored
158 SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
159 {
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
160 int ret = 0;
161 pid_t pid;
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
162 unsigned tocopy;
163 kernel_cap_t pE, pI, pP;
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
164
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
165 ret = cap_validate_magic(header, &tocopy);
c4a5af5 Silence the existing API for capability version compatibility check.
Andrew G. Morgan authored
166 if ((dataptr == NULL) || (ret != 0))
167 return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
168
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
169 if (get_user(pid, &header->pid))
170 return -EFAULT;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
171
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
172 if (pid < 0)
173 return -EINVAL;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
174
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
175 ret = cap_get_target_pid(pid, &pE, &pI, &pP);
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
176 if (!ret) {
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
177 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
178 unsigned i;
179
180 for (i = 0; i < tocopy; i++) {
181 kdata[i].effective = pE.cap[i];
182 kdata[i].permitted = pP.cap[i];
183 kdata[i].inheritable = pI.cap[i];
184 }
185
186 /*
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
187 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
188 * we silently drop the upper capabilities here. This
189 * has the effect of making older libcap
190 * implementations implicitly drop upper capability
191 * bits when they perform a: capget/modify/capset
192 * sequence.
193 *
194 * This behavior is considered fail-safe
195 * behavior. Upgrading the application to a newer
196 * version of libcap will enable access to the newer
197 * capabilities.
198 *
199 * An alternative would be to return an error here
200 * (-ERANGE), but that causes legacy applications to
201 * unexpectidly fail; the capget/modify/capset aborts
202 * before modification is attempted and the application
203 * fails.
204 */
205 if (copy_to_user(dataptr, kdata, tocopy
206 * sizeof(struct __user_cap_data_struct))) {
207 return -EFAULT;
208 }
209 }
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
210
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
211 return ret;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
212 }
213
207a7ba [PATCH] kernel/capability.c: add kerneldoc
Randy Dunlap authored
214 /**
ab763c7 security: filesystem capabilities refactor kernel code
Andrew G. Morgan authored
215 * sys_capset - set capabilities for a process or (*) a group of processes
207a7ba [PATCH] kernel/capability.c: add kerneldoc
Randy Dunlap authored
216 * @header: pointer to struct that contains capability version and
217 * target pid data
218 * @data: pointer to struct that contains the effective, permitted,
219 * and inheritable capabilities
220 *
1cdcbec CRED: Neuter sys_capset()
David Howells authored
221 * Set capabilities for the current process only. The ability to any other
222 * process(es) has been deprecated and removed.
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
223 *
224 * The restrictions on setting capabilities are specified as:
225 *
1cdcbec CRED: Neuter sys_capset()
David Howells authored
226 * I: any raised capabilities must be a subset of the old permitted
227 * P: any raised capabilities must be a subset of the old permitted
228 * E: must be set to a subset of new permitted
207a7ba [PATCH] kernel/capability.c: add kerneldoc
Randy Dunlap authored
229 *
230 * Returns 0 on success and < 0 on error.
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
231 */
b290ebe [CVE-2009-0029] System call wrappers part 04
Heiko Carstens authored
232 SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
233 {
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
234 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
825332e capabilities: simplify bound checks for copy_from_user()
Arjan van de Ven authored
235 unsigned i, tocopy, copybytes;
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
236 kernel_cap_t inheritable, permitted, effective;
d84f4f9 CRED: Inaugurate COW credentials
David Howells authored
237 struct cred *new;
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
238 int ret;
239 pid_t pid;
240
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
241 ret = cap_validate_magic(header, &tocopy);
242 if (ret != 0)
243 return ret;
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
244
245 if (get_user(pid, &header->pid))
246 return -EFAULT;
247
1cdcbec CRED: Neuter sys_capset()
David Howells authored
248 /* may only affect current now */
249 if (pid != 0 && pid != task_pid_vnr(current))
250 return -EPERM;
251
825332e capabilities: simplify bound checks for copy_from_user()
Arjan van de Ven authored
252 copybytes = tocopy * sizeof(struct __user_cap_data_struct);
253 if (copybytes > sizeof(kdata))
254 return -EFAULT;
255
256 if (copy_from_user(&kdata, data, copybytes))
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
257 return -EFAULT;
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
258
259 for (i = 0; i < tocopy; i++) {
260 effective.cap[i] = kdata[i].effective;
261 permitted.cap[i] = kdata[i].permitted;
262 inheritable.cap[i] = kdata[i].inheritable;
263 }
ca05a99 capabilities: remain source compatible with 32-bit raw legacy capabil…
Andrew G. Morgan authored
264 while (i < _KERNEL_CAPABILITY_U32S) {
e338d26 Add 64-bit capability support to the kernel
Andrew Morgan authored
265 effective.cap[i] = 0;
266 permitted.cap[i] = 0;
267 inheritable.cap[i] = 0;
268 i++;
269 }
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
270
d84f4f9 CRED: Inaugurate COW credentials
David Howells authored
271 new = prepare_creds();
272 if (!new)
273 return -ENOMEM;
274
275 ret = security_capset(new, current_cred(),
276 &effective, &inheritable, &permitted);
277 if (ret < 0)
278 goto error;
279
57f71a0 sanitize audit_log_capset()
Al Viro authored
280 audit_log_capset(pid, new, current_cred());
e68b75a @eparis When the capset syscall is used it is not possible for audit to recor…
eparis authored
281
d84f4f9 CRED: Inaugurate COW credentials
David Howells authored
282 return commit_creds(new);
283
284 error:
285 abort_creds(new);
314f70f whitespace fixes: capability syscalls
Daniel Walker authored
286 return ret;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
287 }
12b5989 @chriswright [PATCH] refactor capable() to one implementation, add __capable() helper
chriswright authored
288
5cd9c58 security: Fix setting of PF_SUPERPRIV by __capable()
David Howells authored
289 /**
3263245 userns: make has_capability* into real functions
Serge E. Hallyn authored
290 * has_capability - Does a task have a capability in init_user_ns
291 * @t: The task in question
292 * @cap: The capability to be tested for
293 *
294 * Return true if the specified task has the given superior capability
295 * currently in effect to the initial user namespace, false if not.
296 *
297 * Note that this does not set PF_SUPERPRIV on the task.
298 */
299 bool has_capability(struct task_struct *t, int cap)
300 {
301 int ret = security_real_capable(t, &init_user_ns, cap);
302
303 return (ret == 0);
304 }
305
306 /**
307 * has_capability - Does a task have a capability in a specific user ns
308 * @t: The task in question
309 * @ns: target user namespace
310 * @cap: The capability to be tested for
311 *
312 * Return true if the specified task has the given superior capability
313 * currently in effect to the specified user namespace, false if not.
314 *
315 * Note that this does not set PF_SUPERPRIV on the task.
316 */
317 bool has_ns_capability(struct task_struct *t,
318 struct user_namespace *ns, int cap)
319 {
320 int ret = security_real_capable(t, ns, cap);
321
322 return (ret == 0);
323 }
324
325 /**
326 * has_capability_noaudit - Does a task have a capability (unaudited)
327 * @t: The task in question
328 * @cap: The capability to be tested for
329 *
330 * Return true if the specified task has the given superior capability
331 * currently in effect to init_user_ns, false if not. Don't write an
332 * audit message for the check.
333 *
334 * Note that this does not set PF_SUPERPRIV on the task.
335 */
336 bool has_capability_noaudit(struct task_struct *t, int cap)
337 {
338 int ret = security_real_capable_noaudit(t, &init_user_ns, cap);
339
340 return (ret == 0);
341 }
342
343 /**
5cd9c58 security: Fix setting of PF_SUPERPRIV by __capable()
David Howells authored
344 * capable - Determine if the current task has a superior capability in effect
345 * @cap: The capability to be tested for
346 *
347 * Return true if the current task has the given superior capability currently
348 * available for use, false if not.
349 *
350 * This sets PF_SUPERPRIV on the task if the capability is available on the
351 * assumption that it's about to be used.
352 */
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
353 bool capable(int cap)
354 {
355 return ns_capable(&init_user_ns, cap);
356 }
357 EXPORT_SYMBOL(capable);
358
359 /**
360 * ns_capable - Determine if the current task has a superior capability in effect
361 * @ns: The usernamespace we want the capability in
362 * @cap: The capability to be tested for
363 *
364 * Return true if the current task has the given superior capability currently
365 * available for use, false if not.
366 *
367 * This sets PF_SUPERPRIV on the task if the capability is available on the
368 * assumption that it's about to be used.
369 */
370 bool ns_capable(struct user_namespace *ns, int cap)
12b5989 @chriswright [PATCH] refactor capable() to one implementation, add __capable() helper
chriswright authored
371 {
637d32d @eparis Capabilities: BUG when an invalid capability is requested
eparis authored
372 if (unlikely(!cap_valid(cap))) {
373 printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
374 BUG();
375 }
376
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
377 if (security_capable(ns, current_cred(), cap) == 0) {
5cd9c58 security: Fix setting of PF_SUPERPRIV by __capable()
David Howells authored
378 current->flags |= PF_SUPERPRIV;
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
379 return true;
12b5989 @chriswright [PATCH] refactor capable() to one implementation, add __capable() helper
chriswright authored
380 }
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
381 return false;
12b5989 @chriswright [PATCH] refactor capable() to one implementation, add __capable() helper
chriswright authored
382 }
3486740 @hallyn userns: security: make capabilities relative to the user namespace
hallyn authored
383 EXPORT_SYMBOL(ns_capable);
384
385 /**
386 * task_ns_capable - Determine whether current task has a superior
387 * capability targeted at a specific task's user namespace.
388 * @t: The task whose user namespace is targeted.
389 * @cap: The capability in question.
390 *
391 * Return true if it does, false otherwise.
392 */
393 bool task_ns_capable(struct task_struct *t, int cap)
394 {
395 return ns_capable(task_cred_xxx(t, user)->user_ns, cap);
396 }
397 EXPORT_SYMBOL(task_ns_capable);
47a150e Cache user_ns in struct cred
Serge E. Hallyn authored
398
399 /**
400 * nsown_capable - Check superior capability to one's own user_ns
401 * @cap: The capability in question
402 *
403 * Return true if the current task has the given superior capability
404 * targeted at its own user namespace.
405 */
406 bool nsown_capable(int cap)
407 {
408 return ns_capable(current_user_ns(), cap);
409 }
Something went wrong with that request. Please try again.