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>
11 #include <linux/module.h>
12 #include <linux/security.h>
13 #include <asm/uaccess.h>
15 unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
16 kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
18 EXPORT_SYMBOL(securebits);
19 EXPORT_SYMBOL(cap_bset);
22 * This global lock protects task->cap_* for all tasks including current.
23 * Locking rule: acquire this prior to tasklist_lock.
25 spinlock_t task_capability_lock = SPIN_LOCK_UNLOCKED;
28 * For sys_getproccap() and sys_setproccap(), any of the three
29 * capability set pointers may be NULL -- indicating that that set is
30 * uninteresting and/or not to be changed.
34 * sys_capget - get the capabilities of a given process.
36 asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
42 struct __user_cap_data_struct data;
44 if (get_user(version, &header->version))
47 if (version != _LINUX_CAPABILITY_VERSION) {
48 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
53 if (get_user(pid, &header->pid))
59 spin_lock(&task_capability_lock);
60 read_lock(&tasklist_lock);
62 if (pid && pid != current->pid) {
63 target = find_task_by_pid(pid);
71 ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
74 read_unlock(&tasklist_lock);
75 spin_unlock(&task_capability_lock);
77 if (!ret && copy_to_user(dataptr, &data, sizeof data))
84 * cap_set_pg - set capabilities for all processes in a given process
85 * group. We call this holding task_capability_lock and tasklist_lock.
87 static inline void cap_set_pg(int pgrp, kernel_cap_t *effective,
88 kernel_cap_t *inheritable,
89 kernel_cap_t *permitted)
93 do_each_task_pid(pgrp, PIDTYPE_PGID, g) {
95 while_each_thread(g, target)
96 security_capset_set(target, effective, inheritable, permitted);
97 } while_each_task_pid(pgrp, PIDTYPE_PGID, g);
101 * cap_set_all - set capabilities for all processes other than init
102 * and self. We call this holding task_capability_lock and tasklist_lock.
104 static inline void cap_set_all(kernel_cap_t *effective,
105 kernel_cap_t *inheritable,
106 kernel_cap_t *permitted)
110 do_each_thread(g, target) {
111 if (target == current || target->pid == 1)
113 security_capset_set(target, effective, inheritable, permitted);
114 } while_each_thread(g, target);
118 * sys_capset - set capabilities for a given process, all processes, or all
119 * processes in a given process group.
121 * The restrictions on setting capabilities are specified as:
123 * [pid is for the 'target' task. 'current' is the calling task.]
125 * I: any raised capabilities must be a subset of the (old current) permitted
126 * P: any raised capabilities must be a subset of the (old current) permitted
127 * E: must be set to a subset of (new target) permitted
129 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
131 kernel_cap_t inheritable, permitted, effective;
137 if (get_user(version, &header->version))
140 if (version != _LINUX_CAPABILITY_VERSION) {
141 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
146 if (get_user(pid, &header->pid))
149 if (pid && !capable(CAP_SETPCAP))
152 if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
153 copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
154 copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
157 spin_lock(&task_capability_lock);
158 read_lock(&tasklist_lock);
160 if (pid > 0 && pid != current->pid) {
161 target = find_task_by_pid(pid);
171 if (security_capset_check(target, &effective, &inheritable, &permitted))
174 if (!cap_issubset(inheritable, cap_combine(target->cap_inheritable,
175 current->cap_permitted)))
178 /* verify restrictions on target's new Permitted set */
179 if (!cap_issubset(permitted, cap_combine(target->cap_permitted,
180 current->cap_permitted)))
183 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
184 if (!cap_issubset(effective, permitted))
189 /* having verified that the proposed changes are legal,
190 we now put them into effect. */
192 if (pid == -1) /* all procs other than current and init */
193 cap_set_all(&effective, &inheritable, &permitted);
195 else /* all procs in process group */
196 cap_set_pg(-pid, &effective, &inheritable, &permitted);
198 security_capset_set(target, &effective, &inheritable, &permitted);
202 read_unlock(&tasklist_lock);
203 spin_unlock(&task_capability_lock);