2 * linux/kernel/capability.c
4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org>
6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
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>
18 * This lock protects task->cap_* for all tasks including current.
19 * Locking rule: acquire this prior to tasklist_lock.
21 static DEFINE_SPINLOCK(task_capability_lock
);
24 * For sys_getproccap() and sys_setproccap(), any of the three
25 * capability set pointers may be NULL -- indicating that that set is
26 * uninteresting and/or not to be changed.
30 * sys_capget - get the capabilities of a given process.
31 * @header: pointer to struct that contains capability version and
33 * @dataptr: pointer to struct that contains the effective, permitted,
34 * and inheritable capabilities that are returned
36 * Returns 0 on success and < 0 on error.
38 asmlinkage
long sys_capget(cap_user_header_t header
, cap_user_data_t dataptr
)
43 struct task_struct
*target
;
44 struct __user_cap_data_struct data
;
46 if (get_user(version
, &header
->version
))
49 if (version
!= _LINUX_CAPABILITY_VERSION
) {
50 if (put_user(_LINUX_CAPABILITY_VERSION
, &header
->version
))
55 if (get_user(pid
, &header
->pid
))
61 spin_lock(&task_capability_lock
);
62 read_lock(&tasklist_lock
);
64 if (pid
&& pid
!= current
->pid
) {
65 target
= find_task_by_pid(pid
);
73 ret
= security_capget(target
, &data
.effective
, &data
.inheritable
, &data
.permitted
);
76 read_unlock(&tasklist_lock
);
77 spin_unlock(&task_capability_lock
);
79 if (!ret
&& copy_to_user(dataptr
, &data
, sizeof data
))
86 * cap_set_pg - set capabilities for all processes in a given process
87 * group. We call this holding task_capability_lock and tasklist_lock.
89 static inline int cap_set_pg(int pgrp_nr
, kernel_cap_t
*effective
,
90 kernel_cap_t
*inheritable
,
91 kernel_cap_t
*permitted
)
93 struct task_struct
*g
, *target
;
98 pgrp
= find_pid(pgrp_nr
);
99 do_each_pid_task(pgrp
, PIDTYPE_PGID
, g
) {
101 while_each_thread(g
, target
) {
102 if (!security_capset_check(target
, effective
,
105 security_capset_set(target
, effective
,
112 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, g
);
120 * cap_set_all - set capabilities for all processes other than init
121 * and self. We call this holding task_capability_lock and tasklist_lock.
123 static inline int cap_set_all(kernel_cap_t
*effective
,
124 kernel_cap_t
*inheritable
,
125 kernel_cap_t
*permitted
)
127 struct task_struct
*g
, *target
;
131 do_each_thread(g
, target
) {
132 if (target
== current
|| is_init(target
))
135 if (security_capset_check(target
, effective
, inheritable
,
139 security_capset_set(target
, effective
, inheritable
, permitted
);
140 } while_each_thread(g
, target
);
148 * sys_capset - set capabilities for a process or a group of processes
149 * @header: pointer to struct that contains capability version and
151 * @data: pointer to struct that contains the effective, permitted,
152 * and inheritable capabilities
154 * Set capabilities for a given process, all processes, or all
155 * processes in a given process group.
157 * The restrictions on setting capabilities are specified as:
159 * [pid is for the 'target' task. 'current' is the calling task.]
161 * I: any raised capabilities must be a subset of the (old current) permitted
162 * P: any raised capabilities must be a subset of the (old current) permitted
163 * E: must be set to a subset of (new target) permitted
165 * Returns 0 on success and < 0 on error.
167 asmlinkage
long sys_capset(cap_user_header_t header
, const cap_user_data_t data
)
169 kernel_cap_t inheritable
, permitted
, effective
;
171 struct task_struct
*target
;
175 if (get_user(version
, &header
->version
))
178 if (version
!= _LINUX_CAPABILITY_VERSION
) {
179 if (put_user(_LINUX_CAPABILITY_VERSION
, &header
->version
))
184 if (get_user(pid
, &header
->pid
))
187 if (pid
&& pid
!= current
->pid
&& !capable(CAP_SETPCAP
))
190 if (copy_from_user(&effective
, &data
->effective
, sizeof(effective
)) ||
191 copy_from_user(&inheritable
, &data
->inheritable
, sizeof(inheritable
)) ||
192 copy_from_user(&permitted
, &data
->permitted
, sizeof(permitted
)))
195 spin_lock(&task_capability_lock
);
196 read_lock(&tasklist_lock
);
198 if (pid
> 0 && pid
!= current
->pid
) {
199 target
= find_task_by_pid(pid
);
209 /* having verified that the proposed changes are legal,
210 we now put them into effect. */
212 if (pid
== -1) /* all procs other than current and init */
213 ret
= cap_set_all(&effective
, &inheritable
, &permitted
);
215 else /* all procs in process group */
216 ret
= cap_set_pg(-pid
, &effective
, &inheritable
,
219 ret
= security_capset_check(target
, &effective
, &inheritable
,
222 security_capset_set(target
, &effective
, &inheritable
,
227 read_unlock(&tasklist_lock
);
228 spin_unlock(&task_capability_lock
);
233 int __capable(struct task_struct
*t
, int cap
)
235 if (security_capable(t
, cap
) == 0) {
236 t
->flags
|= PF_SUPERPRIV
;
244 return __capable(current
, cap
);
246 EXPORT_SYMBOL(capable
);