[net-next-2.6.git] / kernel / capability.c

/*
 * linux/kernel/capability.c
 *
 * Copyright (C) 1997  Andrew Main <zefram@fysh.org>
 *
 * Integrated into 2.1.97+,  Andrew G. Morgan <morgan@kernel.org>
 * 30 May 2002:	Cleanup, Robert M. Love <rml@tech9.net>
 */

#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pid_namespace.h>
#include <asm/uaccess.h>

/*
 * This lock protects task->cap_* for all tasks including current.
 * Locking rule: acquire this prior to tasklist_lock.
 */
static DEFINE_SPINLOCK(task_capability_lock);

/*
 * For sys_getproccap() and sys_setproccap(), any of the three
 * capability set pointers may be NULL -- indicating that that set is
 * uninteresting and/or not to be changed.
 */

/**
 * sys_capget - get the capabilities of a given process.
 * @header: pointer to struct that contains capability version and
 *	target pid data
 * @dataptr: pointer to struct that contains the effective, permitted,
 *	and inheritable capabilities that are returned
 *
 * Returns 0 on success and < 0 on error.
 */
asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
{
	int ret = 0;
	pid_t pid;
	__u32 version;
	struct task_struct *target;
	struct __user_cap_data_struct data;

	if (get_user(version, &header->version))
		return -EFAULT;

	if (version != _LINUX_CAPABILITY_VERSION) {
		if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
			return -EFAULT;
		return -EINVAL;
	}

	if (get_user(pid, &header->pid))
		return -EFAULT;

	if (pid < 0)
		return -EINVAL;

	spin_lock(&task_capability_lock);
	read_lock(&tasklist_lock);

	if (pid && pid != task_pid_vnr(current)) {
		target = find_task_by_pid_ns(pid,
				current->nsproxy->pid_ns);
		if (!target) {
			ret = -ESRCH;
			goto out;
		}
	} else
		target = current;

	ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);

out:
	read_unlock(&tasklist_lock);
	spin_unlock(&task_capability_lock);

	if (!ret && copy_to_user(dataptr, &data, sizeof data))
		return -EFAULT;

	return ret;
}

/*
 * cap_set_pg - set capabilities for all processes in a given process
 * group.  We call this holding task_capability_lock and tasklist_lock.
 */
static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
			      kernel_cap_t *inheritable,
			      kernel_cap_t *permitted)
{
	struct task_struct *g, *target;
	int ret = -EPERM;
	int found = 0;
	struct pid *pgrp;

	pgrp = find_pid_ns(pgrp_nr, current->nsproxy->pid_ns);
	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
		target = g;
		while_each_thread(g, target) {
			if (!security_capset_check(target, effective,
							inheritable,
							permitted)) {
				security_capset_set(target, effective,
							inheritable,
							permitted);
				ret = 0;
			}
			found = 1;
		}
	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);

	if (!found)
		ret = 0;
	return ret;
}

/*
 * cap_set_all - set capabilities for all processes other than init
 * and self.  We call this holding task_capability_lock and tasklist_lock.
 */
static inline int cap_set_all(kernel_cap_t *effective,
			       kernel_cap_t *inheritable,
			       kernel_cap_t *permitted)
{
     struct task_struct *g, *target;
     int ret = -EPERM;
     int found = 0;

     do_each_thread(g, target) {
             if (target == current || is_container_init(target->group_leader))
                     continue;
             found = 1;
	     if (security_capset_check(target, effective, inheritable,
						permitted))
		     continue;
	     ret = 0;
	     security_capset_set(target, effective, inheritable, permitted);
     } while_each_thread(g, target);

     if (!found)
	     ret = 0;
     return ret;
}

/**
 * sys_capset - set capabilities for a process or a group of processes
 * @header: pointer to struct that contains capability version and
 *	target pid data
 * @data: pointer to struct that contains the effective, permitted,
 *	and inheritable capabilities
 *
 * Set capabilities for a given process, all processes, or all
 * processes in a given process group.
 *
 * The restrictions on setting capabilities are specified as:
 *
 * [pid is for the 'target' task.  'current' is the calling task.]
 *
 * I: any raised capabilities must be a subset of the (old current) permitted
 * P: any raised capabilities must be a subset of the (old current) permitted
 * E: must be set to a subset of (new target) permitted
 *
 * Returns 0 on success and < 0 on error.
 */
asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
{
	kernel_cap_t inheritable, permitted, effective;
	__u32 version;
	struct task_struct *target;
	int ret;
	pid_t pid;

	if (get_user(version, &header->version))
		return -EFAULT;

	if (version != _LINUX_CAPABILITY_VERSION) {
		if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
			return -EFAULT;
		return -EINVAL;
	}

	if (get_user(pid, &header->pid))
		return -EFAULT;

	if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
		return -EPERM;

	if (copy_from_user(&effective, &data->effective, sizeof(effective)) ||
	    copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) ||
	    copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
		return -EFAULT;

	spin_lock(&task_capability_lock);
	read_lock(&tasklist_lock);

	if (pid > 0 && pid != task_pid_vnr(current)) {
		target = find_task_by_pid_ns(pid,
				current->nsproxy->pid_ns);
		if (!target) {
			ret = -ESRCH;
			goto out;
		}
	} else
		target = current;

	ret = 0;

	/* having verified that the proposed changes are legal,
	   we now put them into effect. */
	if (pid < 0) {
		if (pid == -1)	/* all procs other than current and init */
			ret = cap_set_all(&effective, &inheritable, &permitted);

		else		/* all procs in process group */
			ret = cap_set_pg(-pid, &effective, &inheritable,
					 &permitted);
	} else {
		ret = security_capset_check(target, &effective, &inheritable,
					    &permitted);
		if (!ret)
			security_capset_set(target, &effective, &inheritable,
					    &permitted);
	}

out:
	read_unlock(&tasklist_lock);
	spin_unlock(&task_capability_lock);

	return ret;
}

int __capable(struct task_struct *t, int cap)
{
	if (security_capable(t, cap) == 0) {
		t->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

int capable(int cap)
{
	return __capable(current, cap);
}
EXPORT_SYMBOL(capable);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/capability.c
	3	*
	4	* Copyright (C) 1997 Andrew Main <zefram@fysh.org>
	5	*
72c2d582	6	* Integrated into 2.1.97+, Andrew G. Morgan <morgan@kernel.org>
1da177e4	7	* 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
314f70fd	8	*/
1da177e4	9
c59ede7b	10	#include <linux/capability.h>
1da177e4 LT	11	#include <linux/mm.h>
	12	#include <linux/module.h>
	13	#include <linux/security.h>
	14	#include <linux/syscalls.h>
b460cbc5	15	#include <linux/pid_namespace.h>
1da177e4 LT	16	#include <asm/uaccess.h>
1da177e4 LT	17
1da177e4 LT	18	/*
	19	* This lock protects task->cap_* for all tasks including current.
	20	* Locking rule: acquire this prior to tasklist_lock.
	21	*/
	22	static DEFINE_SPINLOCK(task_capability_lock);
	23
	24	/*
	25	* For sys_getproccap() and sys_setproccap(), any of the three
	26	* capability set pointers may be NULL -- indicating that that set is
	27	* uninteresting and/or not to be changed.
	28	*/
	29
207a7ba8	30	/**
1da177e4	31	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	32	* @header: pointer to struct that contains capability version and
	33	* target pid data
	34	* @dataptr: pointer to struct that contains the effective, permitted,
	35	* and inheritable capabilities that are returned
	36	*
	37	* Returns 0 on success and < 0 on error.
1da177e4 LT	38	*/
	39	asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
	40	{
314f70fd DW	41	int ret = 0;
	42	pid_t pid;
	43	__u32 version;
	44	struct task_struct *target;
	45	struct __user_cap_data_struct data;
	46
	47	if (get_user(version, &header->version))
	48	return -EFAULT;
	49
	50	if (version != _LINUX_CAPABILITY_VERSION) {
	51	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	52	return -EFAULT;
	53	return -EINVAL;
	54	}
1da177e4	55
314f70fd DW	56	if (get_user(pid, &header->pid))
314f70fd DW	57	return -EFAULT;
1da177e4	58
314f70fd DW	59	if (pid < 0)
314f70fd DW	60	return -EINVAL;
1da177e4	61
314f70fd DW	62	spin_lock(&task_capability_lock);
314f70fd DW	63	read_lock(&tasklist_lock);
1da177e4	64
b488893a PE	65	if (pid && pid != task_pid_vnr(current)) {
	66	target = find_task_by_pid_ns(pid,
	67	current->nsproxy->pid_ns);
314f70fd DW	68	if (!target) {
	69	ret = -ESRCH;
	70	goto out;
	71	}
	72	} else
	73	target = current;
1da177e4	74
314f70fd	75	ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
1da177e4 LT	76
1da177e4 LT	77	out:
314f70fd DW	78	read_unlock(&tasklist_lock);
314f70fd DW	79	spin_unlock(&task_capability_lock);
1da177e4	80
314f70fd DW	81	if (!ret && copy_to_user(dataptr, &data, sizeof data))
314f70fd DW	82	return -EFAULT;
1da177e4	83
314f70fd	84	return ret;
1da177e4 LT	85	}
	86
	87	/*
	88	* cap_set_pg - set capabilities for all processes in a given process
	89	* group. We call this holding task_capability_lock and tasklist_lock.
	90	*/
41487c65	91	static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
1da177e4 LT	92	kernel_cap_t *inheritable,
	93	kernel_cap_t *permitted)
	94	{
36c8b586	95	struct task_struct g, target;
1da177e4 LT	96	int ret = -EPERM;
1da177e4 LT	97	int found = 0;
41487c65	98	struct pid *pgrp;
1da177e4	99
b488893a	100	pgrp = find_pid_ns(pgrp_nr, current->nsproxy->pid_ns);
41487c65	101	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
1da177e4 LT	102	target = g;
	103	while_each_thread(g, target) {
	104	if (!security_capset_check(target, effective,
	105	inheritable,
	106	permitted)) {
	107	security_capset_set(target, effective,
	108	inheritable,
	109	permitted);
	110	ret = 0;
	111	}
	112	found = 1;
	113	}
41487c65	114	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);
1da177e4 LT	115
1da177e4 LT	116	if (!found)
314f70fd	117	ret = 0;
1da177e4 LT	118	return ret;
	119	}
	120
	121	/*
	122	* cap_set_all - set capabilities for all processes other than init
	123	* and self. We call this holding task_capability_lock and tasklist_lock.
	124	*/
	125	static inline int cap_set_all(kernel_cap_t *effective,
	126	kernel_cap_t *inheritable,
	127	kernel_cap_t *permitted)
	128	{
36c8b586	129	struct task_struct g, target;
1da177e4 LT	130	int ret = -EPERM;
	131	int found = 0;
	132
	133	do_each_thread(g, target) {
b460cbc5	134	if (target == current \|\| is_container_init(target->group_leader))
1da177e4 LT	135	continue;
	136	found = 1;
	137	if (security_capset_check(target, effective, inheritable,
	138	permitted))
	139	continue;
	140	ret = 0;
	141	security_capset_set(target, effective, inheritable, permitted);
	142	} while_each_thread(g, target);
	143
	144	if (!found)
	145	ret = 0;
	146	return ret;
	147	}
	148
207a7ba8 RD	149	/**
	150	* sys_capset - set capabilities for a process or a group of processes
	151	* @header: pointer to struct that contains capability version and
	152	* target pid data
	153	* @data: pointer to struct that contains the effective, permitted,
	154	* and inheritable capabilities
	155	*
	156	* Set capabilities for a given process, all processes, or all
1da177e4 LT	157	* processes in a given process group.
	158	*
	159	* The restrictions on setting capabilities are specified as:
	160	*
	161	* [pid is for the 'target' task. 'current' is the calling task.]
	162	*
	163	* I: any raised capabilities must be a subset of the (old current) permitted
	164	* P: any raised capabilities must be a subset of the (old current) permitted
	165	* E: must be set to a subset of (new target) permitted
207a7ba8 RD	166	*
207a7ba8 RD	167	* Returns 0 on success and < 0 on error.
1da177e4 LT	168	*/
	169	asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
	170	{
314f70fd DW	171	kernel_cap_t inheritable, permitted, effective;
	172	__u32 version;
	173	struct task_struct *target;
	174	int ret;
	175	pid_t pid;
	176
	177	if (get_user(version, &header->version))
	178	return -EFAULT;
	179
	180	if (version != _LINUX_CAPABILITY_VERSION) {
	181	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	182	return -EFAULT;
	183	return -EINVAL;
	184	}
	185
	186	if (get_user(pid, &header->pid))
	187	return -EFAULT;
	188
b488893a	189	if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
314f70fd DW	190	return -EPERM;
	191
	192	if (copy_from_user(&effective, &data->effective, sizeof(effective)) \|\|
	193	copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) \|\|
	194	copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
	195	return -EFAULT;
	196
	197	spin_lock(&task_capability_lock);
	198	read_lock(&tasklist_lock);
	199
b488893a PE	200	if (pid > 0 && pid != task_pid_vnr(current)) {
	201	target = find_task_by_pid_ns(pid,
	202	current->nsproxy->pid_ns);
314f70fd DW	203	if (!target) {
	204	ret = -ESRCH;
	205	goto out;
	206	}
	207	} else
	208	target = current;
	209
	210	ret = 0;
	211
	212	/* having verified that the proposed changes are legal,
	213	we now put them into effect. */
	214	if (pid < 0) {
	215	if (pid == -1) /* all procs other than current and init */
	216	ret = cap_set_all(&effective, &inheritable, &permitted);
	217
	218	else /* all procs in process group */
	219	ret = cap_set_pg(-pid, &effective, &inheritable,
	220	&permitted);
	221	} else {
	222	ret = security_capset_check(target, &effective, &inheritable,
	223	&permitted);
	224	if (!ret)
	225	security_capset_set(target, &effective, &inheritable,
	226	&permitted);
	227	}
1da177e4 LT	228
1da177e4 LT	229	out:
314f70fd DW	230	read_unlock(&tasklist_lock);
314f70fd DW	231	spin_unlock(&task_capability_lock);
1da177e4	232
314f70fd	233	return ret;
1da177e4	234	}
12b5989b CW	235
	236	int __capable(struct task_struct *t, int cap)
	237	{
	238	if (security_capable(t, cap) == 0) {
	239	t->flags \|= PF_SUPERPRIV;
	240	return 1;
	241	}
	242	return 0;
	243	}
12b5989b CW	244
	245	int capable(int cap)
	246	{
	247	return __capable(current, cap);
	248	}
	249	EXPORT_SYMBOL(capable);