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1/*
2 * linux/kernel/capability.c
3 *
4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
5 *
6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/audit.h>
13#include <linux/capability.h>
14#include <linux/mm.h>
15#include <linux/export.h>
16#include <linux/security.h>
17#include <linux/syscalls.h>
18#include <linux/pid_namespace.h>
19#include <linux/user_namespace.h>
20#include <linux/uaccess.h>
21
22/*
23 * Leveraged for setting/resetting capabilities
24 */
25
26const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
27EXPORT_SYMBOL(__cap_empty_set);
28
29int file_caps_enabled = 1;
30
31static int __init file_caps_disable(char *str)
32{
33 file_caps_enabled = 0;
34 return 1;
35}
36__setup("no_file_caps", file_caps_disable);
37
38#ifdef CONFIG_MULTIUSER
39/*
40 * More recent versions of libcap are available from:
41 *
42 * http://www.kernel.org/pub/linux/libs/security/linux-privs/
43 */
44
45static void warn_legacy_capability_use(void)
46{
47 char name[sizeof(current->comm)];
48
49 pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
50 get_task_comm(name, current));
51}
52
53/*
54 * Version 2 capabilities worked fine, but the linux/capability.h file
55 * that accompanied their introduction encouraged their use without
56 * the necessary user-space source code changes. As such, we have
57 * created a version 3 with equivalent functionality to version 2, but
58 * with a header change to protect legacy source code from using
59 * version 2 when it wanted to use version 1. If your system has code
60 * that trips the following warning, it is using version 2 specific
61 * capabilities and may be doing so insecurely.
62 *
63 * The remedy is to either upgrade your version of libcap (to 2.10+,
64 * if the application is linked against it), or recompile your
65 * application with modern kernel headers and this warning will go
66 * away.
67 */
68
69static void warn_deprecated_v2(void)
70{
71 char name[sizeof(current->comm)];
72
73 pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
74 get_task_comm(name, current));
75}
76
77/*
78 * Version check. Return the number of u32s in each capability flag
79 * array, or a negative value on error.
80 */
81static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
82{
83 __u32 version;
84
85 if (get_user(version, &header->version))
86 return -EFAULT;
87
88 switch (version) {
89 case _LINUX_CAPABILITY_VERSION_1:
90 warn_legacy_capability_use();
91 *tocopy = _LINUX_CAPABILITY_U32S_1;
92 break;
93 case _LINUX_CAPABILITY_VERSION_2:
94 warn_deprecated_v2();
95 /*
96 * fall through - v3 is otherwise equivalent to v2.
97 */
98 case _LINUX_CAPABILITY_VERSION_3:
99 *tocopy = _LINUX_CAPABILITY_U32S_3;
100 break;
101 default:
102 if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
103 return -EFAULT;
104 return -EINVAL;
105 }
106
107 return 0;
108}
109
110/*
111 * The only thing that can change the capabilities of the current
112 * process is the current process. As such, we can't be in this code
113 * at the same time as we are in the process of setting capabilities
114 * in this process. The net result is that we can limit our use of
115 * locks to when we are reading the caps of another process.
116 */
117static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
118 kernel_cap_t *pIp, kernel_cap_t *pPp)
119{
120 int ret;
121
122 if (pid && (pid != task_pid_vnr(current))) {
123 struct task_struct *target;
124
125 rcu_read_lock();
126
127 target = find_task_by_vpid(pid);
128 if (!target)
129 ret = -ESRCH;
130 else
131 ret = security_capget(target, pEp, pIp, pPp);
132
133 rcu_read_unlock();
134 } else
135 ret = security_capget(current, pEp, pIp, pPp);
136
137 return ret;
138}
139
140/**
141 * sys_capget - get the capabilities of a given process.
142 * @header: pointer to struct that contains capability version and
143 * target pid data
144 * @dataptr: pointer to struct that contains the effective, permitted,
145 * and inheritable capabilities that are returned
146 *
147 * Returns 0 on success and < 0 on error.
148 */
149SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
150{
151 int ret = 0;
152 pid_t pid;
153 unsigned tocopy;
154 kernel_cap_t pE, pI, pP;
155
156 ret = cap_validate_magic(header, &tocopy);
157 if ((dataptr == NULL) || (ret != 0))
158 return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
159
160 if (get_user(pid, &header->pid))
161 return -EFAULT;
162
163 if (pid < 0)
164 return -EINVAL;
165
166 ret = cap_get_target_pid(pid, &pE, &pI, &pP);
167 if (!ret) {
168 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
169 unsigned i;
170
171 for (i = 0; i < tocopy; i++) {
172 kdata[i].effective = pE.cap[i];
173 kdata[i].permitted = pP.cap[i];
174 kdata[i].inheritable = pI.cap[i];
175 }
176
177 /*
178 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
179 * we silently drop the upper capabilities here. This
180 * has the effect of making older libcap
181 * implementations implicitly drop upper capability
182 * bits when they perform a: capget/modify/capset
183 * sequence.
184 *
185 * This behavior is considered fail-safe
186 * behavior. Upgrading the application to a newer
187 * version of libcap will enable access to the newer
188 * capabilities.
189 *
190 * An alternative would be to return an error here
191 * (-ERANGE), but that causes legacy applications to
192 * unexpectedly fail; the capget/modify/capset aborts
193 * before modification is attempted and the application
194 * fails.
195 */
196 if (copy_to_user(dataptr, kdata, tocopy
197 * sizeof(struct __user_cap_data_struct))) {
198 return -EFAULT;
199 }
200 }
201
202 return ret;
203}
204
205/**
206 * sys_capset - set capabilities for a process or (*) a group of processes
207 * @header: pointer to struct that contains capability version and
208 * target pid data
209 * @data: pointer to struct that contains the effective, permitted,
210 * and inheritable capabilities
211 *
212 * Set capabilities for the current process only. The ability to any other
213 * process(es) has been deprecated and removed.
214 *
215 * The restrictions on setting capabilities are specified as:
216 *
217 * I: any raised capabilities must be a subset of the old permitted
218 * P: any raised capabilities must be a subset of the old permitted
219 * E: must be set to a subset of new permitted
220 *
221 * Returns 0 on success and < 0 on error.
222 */
223SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
224{
225 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
226 unsigned i, tocopy, copybytes;
227 kernel_cap_t inheritable, permitted, effective;
228 struct cred *new;
229 int ret;
230 pid_t pid;
231
232 ret = cap_validate_magic(header, &tocopy);
233 if (ret != 0)
234 return ret;
235
236 if (get_user(pid, &header->pid))
237 return -EFAULT;
238
239 /* may only affect current now */
240 if (pid != 0 && pid != task_pid_vnr(current))
241 return -EPERM;
242
243 copybytes = tocopy * sizeof(struct __user_cap_data_struct);
244 if (copybytes > sizeof(kdata))
245 return -EFAULT;
246
247 if (copy_from_user(&kdata, data, copybytes))
248 return -EFAULT;
249
250 for (i = 0; i < tocopy; i++) {
251 effective.cap[i] = kdata[i].effective;
252 permitted.cap[i] = kdata[i].permitted;
253 inheritable.cap[i] = kdata[i].inheritable;
254 }
255 while (i < _KERNEL_CAPABILITY_U32S) {
256 effective.cap[i] = 0;
257 permitted.cap[i] = 0;
258 inheritable.cap[i] = 0;
259 i++;
260 }
261
262 effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
263 permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
264 inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
265
266 new = prepare_creds();
267 if (!new)
268 return -ENOMEM;
269
270 ret = security_capset(new, current_cred(),
271 &effective, &inheritable, &permitted);
272 if (ret < 0)
273 goto error;
274
275 audit_log_capset(new, current_cred());
276
277 return commit_creds(new);
278
279error:
280 abort_creds(new);
281 return ret;
282}
283
284/**
285 * has_ns_capability - Does a task have a capability in a specific user ns
286 * @t: The task in question
287 * @ns: target user namespace
288 * @cap: The capability to be tested for
289 *
290 * Return true if the specified task has the given superior capability
291 * currently in effect to the specified user namespace, false if not.
292 *
293 * Note that this does not set PF_SUPERPRIV on the task.
294 */
295bool has_ns_capability(struct task_struct *t,
296 struct user_namespace *ns, int cap)
297{
298 int ret;
299
300 rcu_read_lock();
301 ret = security_capable(__task_cred(t), ns, cap);
302 rcu_read_unlock();
303
304 return (ret == 0);
305}
306
307/**
308 * has_capability - Does a task have a capability in init_user_ns
309 * @t: The task in question
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 initial user namespace, false if not.
314 *
315 * Note that this does not set PF_SUPERPRIV on the task.
316 */
317bool has_capability(struct task_struct *t, int cap)
318{
319 return has_ns_capability(t, &init_user_ns, cap);
320}
321EXPORT_SYMBOL(has_capability);
322
323/**
324 * has_ns_capability_noaudit - Does a task have a capability (unaudited)
325 * in a specific user ns.
326 * @t: The task in question
327 * @ns: target user namespace
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 the specified user namespace, false if not.
332 * Do not write an audit message for the check.
333 *
334 * Note that this does not set PF_SUPERPRIV on the task.
335 */
336bool has_ns_capability_noaudit(struct task_struct *t,
337 struct user_namespace *ns, int cap)
338{
339 int ret;
340
341 rcu_read_lock();
342 ret = security_capable_noaudit(__task_cred(t), ns, cap);
343 rcu_read_unlock();
344
345 return (ret == 0);
346}
347
348/**
349 * has_capability_noaudit - Does a task have a capability (unaudited) in the
350 * initial user ns
351 * @t: The task in question
352 * @cap: The capability to be tested for
353 *
354 * Return true if the specified task has the given superior capability
355 * currently in effect to init_user_ns, false if not. Don't write an
356 * audit message for the check.
357 *
358 * Note that this does not set PF_SUPERPRIV on the task.
359 */
360bool has_capability_noaudit(struct task_struct *t, int cap)
361{
362 return has_ns_capability_noaudit(t, &init_user_ns, cap);
363}
364
365static bool ns_capable_common(struct user_namespace *ns, int cap, bool audit)
366{
367 int capable;
368
369 if (unlikely(!cap_valid(cap))) {
370 pr_crit("capable() called with invalid cap=%u\n", cap);
371 BUG();
372 }
373
374 capable = audit ? security_capable(current_cred(), ns, cap) :
375 security_capable_noaudit(current_cred(), ns, cap);
376 if (capable == 0) {
377 current->flags |= PF_SUPERPRIV;
378 return true;
379 }
380 return false;
381}
382
383/**
384 * ns_capable - Determine if the current task has a superior capability in effect
385 * @ns: The usernamespace we want the capability in
386 * @cap: The capability to be tested for
387 *
388 * Return true if the current task has the given superior capability currently
389 * available for use, false if not.
390 *
391 * This sets PF_SUPERPRIV on the task if the capability is available on the
392 * assumption that it's about to be used.
393 */
394bool ns_capable(struct user_namespace *ns, int cap)
395{
396 return ns_capable_common(ns, cap, true);
397}
398EXPORT_SYMBOL(ns_capable);
399
400/**
401 * ns_capable_noaudit - Determine if the current task has a superior capability
402 * (unaudited) in effect
403 * @ns: The usernamespace we want the capability in
404 * @cap: The capability to be tested for
405 *
406 * Return true if the current task has the given superior capability currently
407 * available for use, false if not.
408 *
409 * This sets PF_SUPERPRIV on the task if the capability is available on the
410 * assumption that it's about to be used.
411 */
412bool ns_capable_noaudit(struct user_namespace *ns, int cap)
413{
414 return ns_capable_common(ns, cap, false);
415}
416EXPORT_SYMBOL(ns_capable_noaudit);
417
418/**
419 * capable - Determine if the current task has a superior capability in effect
420 * @cap: The capability to be tested for
421 *
422 * Return true if the current task has the given superior capability currently
423 * available for use, false if not.
424 *
425 * This sets PF_SUPERPRIV on the task if the capability is available on the
426 * assumption that it's about to be used.
427 */
428bool capable(int cap)
429{
430 return ns_capable(&init_user_ns, cap);
431}
432EXPORT_SYMBOL(capable);
433#endif /* CONFIG_MULTIUSER */
434
435/**
436 * file_ns_capable - Determine if the file's opener had a capability in effect
437 * @file: The file we want to check
438 * @ns: The usernamespace we want the capability in
439 * @cap: The capability to be tested for
440 *
441 * Return true if task that opened the file had a capability in effect
442 * when the file was opened.
443 *
444 * This does not set PF_SUPERPRIV because the caller may not
445 * actually be privileged.
446 */
447bool file_ns_capable(const struct file *file, struct user_namespace *ns,
448 int cap)
449{
450 if (WARN_ON_ONCE(!cap_valid(cap)))
451 return false;
452
453 if (security_capable(file->f_cred, ns, cap) == 0)
454 return true;
455
456 return false;
457}
458EXPORT_SYMBOL(file_ns_capable);
459
460/**
461 * privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode?
462 * @ns: The user namespace in question
463 * @inode: The inode in question
464 *
465 * Return true if the inode uid and gid are within the namespace.
466 */
467bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode)
468{
469 return kuid_has_mapping(ns, inode->i_uid) &&
470 kgid_has_mapping(ns, inode->i_gid);
471}
472
473/**
474 * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
475 * @inode: The inode in question
476 * @cap: The capability in question
477 *
478 * Return true if the current task has the given capability targeted at
479 * its own user namespace and that the given inode's uid and gid are
480 * mapped into the current user namespace.
481 */
482bool capable_wrt_inode_uidgid(const struct inode *inode, int cap)
483{
484 struct user_namespace *ns = current_user_ns();
485
486 return ns_capable(ns, cap) && privileged_wrt_inode_uidgid(ns, inode);
487}
488EXPORT_SYMBOL(capable_wrt_inode_uidgid);
489
490/**
491 * ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace
492 * @tsk: The task that may be ptraced
493 * @ns: The user namespace to search for CAP_SYS_PTRACE in
494 *
495 * Return true if the task that is ptracing the current task had CAP_SYS_PTRACE
496 * in the specified user namespace.
497 */
498bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
499{
500 int ret = 0; /* An absent tracer adds no restrictions */
501 const struct cred *cred;
502 rcu_read_lock();
503 cred = rcu_dereference(tsk->ptracer_cred);
504 if (cred)
505 ret = security_capable_noaudit(cred, ns, CAP_SYS_PTRACE);
506 rcu_read_unlock();
507 return (ret == 0);
508}
1/*
2 * linux/kernel/capability.c
3 *
4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
5 *
6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
8 */
9
10#include <linux/audit.h>
11#include <linux/capability.h>
12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/security.h>
15#include <linux/syscalls.h>
16#include <linux/pid_namespace.h>
17#include <linux/user_namespace.h>
18#include <asm/uaccess.h>
19
20/*
21 * Leveraged for setting/resetting capabilities
22 */
23
24const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
25
26EXPORT_SYMBOL(__cap_empty_set);
27
28int file_caps_enabled = 1;
29
30static 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
37/*
38 * More recent versions of libcap are available from:
39 *
40 * http://www.kernel.org/pub/linux/libs/security/linux-privs/
41 */
42
43static 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/*
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
72static 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 */
90static 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
119/*
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.
125 */
126static 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
134 rcu_read_lock();
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
142 rcu_read_unlock();
143 } else
144 ret = security_capget(current, pEp, pIp, pPp);
145
146 return ret;
147}
148
149/**
150 * sys_capget - get the capabilities of a given process.
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.
157 */
158SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
159{
160 int ret = 0;
161 pid_t pid;
162 unsigned tocopy;
163 kernel_cap_t pE, pI, pP;
164
165 ret = cap_validate_magic(header, &tocopy);
166 if ((dataptr == NULL) || (ret != 0))
167 return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
168
169 if (get_user(pid, &header->pid))
170 return -EFAULT;
171
172 if (pid < 0)
173 return -EINVAL;
174
175 ret = cap_get_target_pid(pid, &pE, &pI, &pP);
176 if (!ret) {
177 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
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 /*
187 * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
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 }
210
211 return ret;
212}
213
214/**
215 * sys_capset - set capabilities for a process or (*) a group of processes
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 *
221 * Set capabilities for the current process only. The ability to any other
222 * process(es) has been deprecated and removed.
223 *
224 * The restrictions on setting capabilities are specified as:
225 *
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
229 *
230 * Returns 0 on success and < 0 on error.
231 */
232SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
233{
234 struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
235 unsigned i, tocopy, copybytes;
236 kernel_cap_t inheritable, permitted, effective;
237 struct cred *new;
238 int ret;
239 pid_t pid;
240
241 ret = cap_validate_magic(header, &tocopy);
242 if (ret != 0)
243 return ret;
244
245 if (get_user(pid, &header->pid))
246 return -EFAULT;
247
248 /* may only affect current now */
249 if (pid != 0 && pid != task_pid_vnr(current))
250 return -EPERM;
251
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))
257 return -EFAULT;
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 }
264 while (i < _KERNEL_CAPABILITY_U32S) {
265 effective.cap[i] = 0;
266 permitted.cap[i] = 0;
267 inheritable.cap[i] = 0;
268 i++;
269 }
270
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
280 audit_log_capset(pid, new, current_cred());
281
282 return commit_creds(new);
283
284error:
285 abort_creds(new);
286 return ret;
287}
288
289/**
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 */
299bool 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 */
317bool 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 */
336bool 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/**
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 */
353bool capable(int cap)
354{
355 return ns_capable(&init_user_ns, cap);
356}
357EXPORT_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 */
370bool ns_capable(struct user_namespace *ns, int cap)
371{
372 if (unlikely(!cap_valid(cap))) {
373 printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
374 BUG();
375 }
376
377 if (security_capable(ns, current_cred(), cap) == 0) {
378 current->flags |= PF_SUPERPRIV;
379 return true;
380 }
381 return false;
382}
383EXPORT_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 */
393bool task_ns_capable(struct task_struct *t, int cap)
394{
395 return ns_capable(task_cred_xxx(t, user)->user_ns, cap);
396}
397EXPORT_SYMBOL(task_ns_capable);
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 */
406bool nsown_capable(int cap)
407{
408 return ns_capable(current_user_ns(), cap);
409}