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)
95 for_each_task_pid(pgrp, PIDTYPE_PGID, g, l, pid) {
97 while_each_thread(g, target)
98 security_capset_set(target, effective, inheritable, permitted);
103 * cap_set_all - set capabilities for all processes other than init
104 * and self. We call this holding task_capability_lock and tasklist_lock.
106 static inline void cap_set_all(kernel_cap_t *effective,
107 kernel_cap_t *inheritable,
108 kernel_cap_t *permitted)
112 do_each_thread(g, target) {
113 if (target == current || target->pid == 1)
115 security_capset_set(target, effective, inheritable, permitted);
116 } while_each_thread(g, target);
120 * sys_capset - set capabilities for a given process, all processes, or all
121 * processes in a given process group.
123 * The restrictions on setting capabilities are specified as:
125 * [pid is for the 'target' task. 'current' is the calling task.]
127 * I: any raised capabilities must be a subset of the (old current) permitted
128 * P: any raised capabilities must be a subset of the (old current) permitted
129 * E: must be set to a subset of (new target) permitted
131 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
133 kernel_cap_t inheritable, permitted, effective;
139 if (get_user(version, &header->version))
142 if (version != _LINUX_CAPABILITY_VERSION) {
143 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
148 if (get_user(pid, &header->pid))
151 if (pid && !capable(CAP_SETPCAP))
154 if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
155 copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
156 copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
159 spin_lock(&task_capability_lock);
160 read_lock(&tasklist_lock);
162 if (pid > 0 && pid != current->pid) {
163 target = find_task_by_pid(pid);
173 if (security_capset_check(target, &effective, &inheritable, &permitted))
176 if (!cap_issubset(inheritable, cap_combine(target->cap_inheritable,
177 current->cap_permitted)))
180 /* verify restrictions on target's new Permitted set */
181 if (!cap_issubset(permitted, cap_combine(target->cap_permitted,
182 current->cap_permitted)))
185 /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
186 if (!cap_issubset(effective, permitted))
191 /* having verified that the proposed changes are legal,
192 we now put them into effect. */
194 if (pid == -1) /* all procs other than current and init */
195 cap_set_all(&effective, &inheritable, &permitted);
197 else /* all procs in process group */
198 cap_set_pg(-pid, &effective, &inheritable, &permitted);
200 security_capset_set(target, &effective, &inheritable, &permitted);
204 read_unlock(&tasklist_lock);
205 spin_unlock(&task_capability_lock);