2 * linux/kernel/capability.c
4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com>
7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
10 #include <linux/capability.h>
12 #include <linux/module.h>
13 #include <linux/security.h>
14 #include <linux/syscalls.h>
15 #include <asm/uaccess.h>
17 unsigned securebits
= SECUREBITS_DEFAULT
; /* systemwide security settings */
18 kernel_cap_t cap_bset
= CAP_INIT_EFF_SET
;
20 EXPORT_SYMBOL(securebits
);
21 EXPORT_SYMBOL(cap_bset
);
24 * This lock protects task->cap_* for all tasks including current.
25 * Locking rule: acquire this prior to tasklist_lock.
27 static DEFINE_SPINLOCK(task_capability_lock
);
30 * For sys_getproccap() and sys_setproccap(), any of the three
31 * capability set pointers may be NULL -- indicating that that set is
32 * uninteresting and/or not to be changed.
36 * sys_capget - get the capabilities of a given process.
37 * @header: pointer to struct that contains capability version and
39 * @dataptr: pointer to struct that contains the effective, permitted,
40 * and inheritable capabilities that are returned
42 * Returns 0 on success and < 0 on error.
44 asmlinkage
long sys_capget(cap_user_header_t header
, cap_user_data_t dataptr
)
49 struct task_struct
*target
;
50 struct __user_cap_data_struct data
;
52 if (get_user(version
, &header
->version
))
55 if (version
!= _LINUX_CAPABILITY_VERSION
) {
56 if (put_user(_LINUX_CAPABILITY_VERSION
, &header
->version
))
61 if (get_user(pid
, &header
->pid
))
67 spin_lock(&task_capability_lock
);
68 read_lock(&tasklist_lock
);
70 if (pid
&& pid
!= current
->pid
) {
71 target
= find_task_by_pid(pid
);
79 ret
= security_capget(target
, &data
.effective
, &data
.inheritable
, &data
.permitted
);
82 read_unlock(&tasklist_lock
);
83 spin_unlock(&task_capability_lock
);
85 if (!ret
&& copy_to_user(dataptr
, &data
, sizeof data
))
92 * cap_set_pg - set capabilities for all processes in a given process
93 * group. We call this holding task_capability_lock and tasklist_lock.
95 static inline int cap_set_pg(int pgrp_nr
, kernel_cap_t
*effective
,
96 kernel_cap_t
*inheritable
,
97 kernel_cap_t
*permitted
)
99 struct task_struct
*g
, *target
;
104 pgrp
= find_pid(pgrp_nr
);
105 do_each_pid_task(pgrp
, PIDTYPE_PGID
, g
) {
107 while_each_thread(g
, target
) {
108 if (!security_capset_check(target
, effective
,
111 security_capset_set(target
, effective
,
118 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, g
);
126 * cap_set_all - set capabilities for all processes other than init
127 * and self. We call this holding task_capability_lock and tasklist_lock.
129 static inline int cap_set_all(kernel_cap_t
*effective
,
130 kernel_cap_t
*inheritable
,
131 kernel_cap_t
*permitted
)
133 struct task_struct
*g
, *target
;
137 do_each_thread(g
, target
) {
138 if (target
== current
|| is_init(target
))
141 if (security_capset_check(target
, effective
, inheritable
,
145 security_capset_set(target
, effective
, inheritable
, permitted
);
146 } while_each_thread(g
, target
);
154 * sys_capset - set capabilities for a process or a group of processes
155 * @header: pointer to struct that contains capability version and
157 * @data: pointer to struct that contains the effective, permitted,
158 * and inheritable capabilities
160 * Set capabilities for a given process, all processes, or all
161 * processes in a given process group.
163 * The restrictions on setting capabilities are specified as:
165 * [pid is for the 'target' task. 'current' is the calling task.]
167 * I: any raised capabilities must be a subset of the (old current) permitted
168 * P: any raised capabilities must be a subset of the (old current) permitted
169 * E: must be set to a subset of (new target) permitted
171 * Returns 0 on success and < 0 on error.
173 asmlinkage
long sys_capset(cap_user_header_t header
, const cap_user_data_t data
)
175 kernel_cap_t inheritable
, permitted
, effective
;
177 struct task_struct
*target
;
181 if (get_user(version
, &header
->version
))
184 if (version
!= _LINUX_CAPABILITY_VERSION
) {
185 if (put_user(_LINUX_CAPABILITY_VERSION
, &header
->version
))
190 if (get_user(pid
, &header
->pid
))
193 if (pid
&& pid
!= current
->pid
&& !capable(CAP_SETPCAP
))
196 if (copy_from_user(&effective
, &data
->effective
, sizeof(effective
)) ||
197 copy_from_user(&inheritable
, &data
->inheritable
, sizeof(inheritable
)) ||
198 copy_from_user(&permitted
, &data
->permitted
, sizeof(permitted
)))
201 spin_lock(&task_capability_lock
);
202 read_lock(&tasklist_lock
);
204 if (pid
> 0 && pid
!= current
->pid
) {
205 target
= find_task_by_pid(pid
);
215 /* having verified that the proposed changes are legal,
216 we now put them into effect. */
218 if (pid
== -1) /* all procs other than current and init */
219 ret
= cap_set_all(&effective
, &inheritable
, &permitted
);
221 else /* all procs in process group */
222 ret
= cap_set_pg(-pid
, &effective
, &inheritable
,
225 ret
= security_capset_check(target
, &effective
, &inheritable
,
228 security_capset_set(target
, &effective
, &inheritable
,
233 read_unlock(&tasklist_lock
);
234 spin_unlock(&task_capability_lock
);
239 int __capable(struct task_struct
*t
, int cap
)
241 if (security_capable(t
, cap
) == 0) {
242 t
->flags
|= PF_SUPERPRIV
;
247 EXPORT_SYMBOL(__capable
);
251 return __capable(current
, cap
);
253 EXPORT_SYMBOL(capable
);