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;
21 * This lock protects task->cap_* for all tasks including current.
22 * Locking rule: acquire this prior to tasklist_lock.
24 static DEFINE_SPINLOCK(task_capability_lock);
27 * For sys_getproccap() and sys_setproccap(), any of the three
28 * capability set pointers may be NULL -- indicating that that set is
29 * uninteresting and/or not to be changed.
33 * sys_capget - get the capabilities of a given process.
34 * @header: pointer to struct that contains capability version and
36 * @dataptr: pointer to struct that contains the effective, permitted,
37 * and inheritable capabilities that are returned
39 * Returns 0 on success and < 0 on error.
41 asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
46 struct task_struct *target;
47 struct __user_cap_data_struct data;
49 if (get_user(version, &header->version))
52 if (version != _LINUX_CAPABILITY_VERSION) {
53 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
58 if (get_user(pid, &header->pid))
64 spin_lock(&task_capability_lock);
65 read_lock(&tasklist_lock);
67 if (pid && pid != current->pid) {
68 target = find_task_by_pid(pid);
76 ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
79 read_unlock(&tasklist_lock);
80 spin_unlock(&task_capability_lock);
82 if (!ret && copy_to_user(dataptr, &data, sizeof data))
89 * cap_set_pg - set capabilities for all processes in a given process
90 * group. We call this holding task_capability_lock and tasklist_lock.
92 static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
93 kernel_cap_t *inheritable,
94 kernel_cap_t *permitted)
96 struct task_struct *g, *target;
101 pgrp = find_pid(pgrp_nr);
102 do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
104 while_each_thread(g, target) {
105 if (!security_capset_check(target, effective,
108 security_capset_set(target, effective,
115 } while_each_pid_task(pgrp, PIDTYPE_PGID, g);
123 * cap_set_all - set capabilities for all processes other than init
124 * and self. We call this holding task_capability_lock and tasklist_lock.
126 static inline int cap_set_all(kernel_cap_t *effective,
127 kernel_cap_t *inheritable,
128 kernel_cap_t *permitted)
130 struct task_struct *g, *target;
134 do_each_thread(g, target) {
135 if (target == current || is_init(target))
138 if (security_capset_check(target, effective, inheritable,
142 security_capset_set(target, effective, inheritable, permitted);
143 } while_each_thread(g, target);
151 * sys_capset - set capabilities for a process or a group of processes
152 * @header: pointer to struct that contains capability version and
154 * @data: pointer to struct that contains the effective, permitted,
155 * and inheritable capabilities
157 * Set capabilities for a given process, all processes, or all
158 * processes in a given process group.
160 * The restrictions on setting capabilities are specified as:
162 * [pid is for the 'target' task. 'current' is the calling task.]
164 * I: any raised capabilities must be a subset of the (old current) permitted
165 * P: any raised capabilities must be a subset of the (old current) permitted
166 * E: must be set to a subset of (new target) permitted
168 * Returns 0 on success and < 0 on error.
170 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
172 kernel_cap_t inheritable, permitted, effective;
174 struct task_struct *target;
178 if (get_user(version, &header->version))
181 if (version != _LINUX_CAPABILITY_VERSION) {
182 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
187 if (get_user(pid, &header->pid))
190 if (pid && pid != current->pid && !capable(CAP_SETPCAP))
193 if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
194 copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
195 copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
198 spin_lock(&task_capability_lock);
199 read_lock(&tasklist_lock);
201 if (pid > 0 && pid != current->pid) {
202 target = find_task_by_pid(pid);
212 /* having verified that the proposed changes are legal,
213 we now put them into effect. */
215 if (pid == -1) /* all procs other than current and init */
216 ret = cap_set_all(&effective, &inheritable, &permitted);
218 else /* all procs in process group */
219 ret = cap_set_pg(-pid, &effective, &inheritable,
222 ret = security_capset_check(target, &effective, &inheritable,
225 security_capset_set(target, &effective, &inheritable,
230 read_unlock(&tasklist_lock);
231 spin_unlock(&task_capability_lock);
236 int __capable(struct task_struct *t, int cap)
238 if (security_capable(t, cap) == 0) {
239 t->flags |= PF_SUPERPRIV;
247 return __capable(current, cap);
249 EXPORT_SYMBOL(capable);