[linux-block.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_vpid(pid);
		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_vpid(pgrp_nr);
	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_vpid(pid);
		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	65	if (pid && pid != task_pid_vnr(current)) {
228ebcbe	66	target = find_task_by_vpid(pid);
314f70fd DW	67	if (!target) {
	68	ret = -ESRCH;
	69	goto out;
	70	}
	71	} else
	72	target = current;
1da177e4	73
314f70fd	74	ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
1da177e4 LT	75
1da177e4 LT	76	out:
314f70fd DW	77	read_unlock(&tasklist_lock);
314f70fd DW	78	spin_unlock(&task_capability_lock);
1da177e4	79
314f70fd DW	80	if (!ret && copy_to_user(dataptr, &data, sizeof data))
314f70fd DW	81	return -EFAULT;
1da177e4	82
314f70fd	83	return ret;
1da177e4 LT	84	}
	85
	86	/*
	87	* cap_set_pg - set capabilities for all processes in a given process
	88	* group. We call this holding task_capability_lock and tasklist_lock.
	89	*/
41487c65	90	static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
1da177e4 LT	91	kernel_cap_t *inheritable,
	92	kernel_cap_t *permitted)
	93	{
36c8b586	94	struct task_struct g, target;
1da177e4 LT	95	int ret = -EPERM;
1da177e4 LT	96	int found = 0;
41487c65	97	struct pid *pgrp;
1da177e4	98
8990571e	99	pgrp = find_vpid(pgrp_nr);
41487c65	100	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
1da177e4 LT	101	target = g;
	102	while_each_thread(g, target) {
	103	if (!security_capset_check(target, effective,
	104	inheritable,
	105	permitted)) {
	106	security_capset_set(target, effective,
	107	inheritable,
	108	permitted);
	109	ret = 0;
	110	}
	111	found = 1;
	112	}
41487c65	113	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);
1da177e4 LT	114
1da177e4 LT	115	if (!found)
314f70fd	116	ret = 0;
1da177e4 LT	117	return ret;
	118	}
	119
	120	/*
	121	* cap_set_all - set capabilities for all processes other than init
	122	* and self. We call this holding task_capability_lock and tasklist_lock.
	123	*/
	124	static inline int cap_set_all(kernel_cap_t *effective,
	125	kernel_cap_t *inheritable,
	126	kernel_cap_t *permitted)
	127	{
36c8b586	128	struct task_struct g, target;
1da177e4 LT	129	int ret = -EPERM;
	130	int found = 0;
	131
	132	do_each_thread(g, target) {
b460cbc5	133	if (target == current \|\| is_container_init(target->group_leader))
1da177e4 LT	134	continue;
	135	found = 1;
	136	if (security_capset_check(target, effective, inheritable,
	137	permitted))
	138	continue;
	139	ret = 0;
	140	security_capset_set(target, effective, inheritable, permitted);
	141	} while_each_thread(g, target);
	142
	143	if (!found)
	144	ret = 0;
	145	return ret;
	146	}
	147
207a7ba8 RD	148	/**
	149	* sys_capset - set capabilities for a process or a group of processes
	150	* @header: pointer to struct that contains capability version and
	151	* target pid data
	152	* @data: pointer to struct that contains the effective, permitted,
	153	* and inheritable capabilities
	154	*
	155	* Set capabilities for a given process, all processes, or all
1da177e4 LT	156	* processes in a given process group.
	157	*
	158	* The restrictions on setting capabilities are specified as:
	159	*
	160	* [pid is for the 'target' task. 'current' is the calling task.]
	161	*
	162	* I: any raised capabilities must be a subset of the (old current) permitted
	163	* P: any raised capabilities must be a subset of the (old current) permitted
	164	* E: must be set to a subset of (new target) permitted
207a7ba8 RD	165	*
207a7ba8 RD	166	* Returns 0 on success and < 0 on error.
1da177e4 LT	167	*/
	168	asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
	169	{
314f70fd DW	170	kernel_cap_t inheritable, permitted, effective;
	171	__u32 version;
	172	struct task_struct *target;
	173	int ret;
	174	pid_t pid;
	175
	176	if (get_user(version, &header->version))
	177	return -EFAULT;
	178
	179	if (version != _LINUX_CAPABILITY_VERSION) {
	180	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	181	return -EFAULT;
	182	return -EINVAL;
	183	}
	184
	185	if (get_user(pid, &header->pid))
	186	return -EFAULT;
	187
b488893a	188	if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
314f70fd DW	189	return -EPERM;
	190
	191	if (copy_from_user(&effective, &data->effective, sizeof(effective)) \|\|
	192	copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) \|\|
	193	copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
	194	return -EFAULT;
	195
	196	spin_lock(&task_capability_lock);
	197	read_lock(&tasklist_lock);
	198
b488893a	199	if (pid > 0 && pid != task_pid_vnr(current)) {
228ebcbe	200	target = find_task_by_vpid(pid);
314f70fd DW	201	if (!target) {
	202	ret = -ESRCH;
	203	goto out;
	204	}
	205	} else
	206	target = current;
	207
	208	ret = 0;
	209
	210	/* having verified that the proposed changes are legal,
	211	we now put them into effect. */
	212	if (pid < 0) {
	213	if (pid == -1) /* all procs other than current and init */
	214	ret = cap_set_all(&effective, &inheritable, &permitted);
	215
	216	else /* all procs in process group */
	217	ret = cap_set_pg(-pid, &effective, &inheritable,
	218	&permitted);
	219	} else {
	220	ret = security_capset_check(target, &effective, &inheritable,
	221	&permitted);
	222	if (!ret)
	223	security_capset_set(target, &effective, &inheritable,
	224	&permitted);
	225	}
1da177e4 LT	226
1da177e4 LT	227	out:
314f70fd DW	228	read_unlock(&tasklist_lock);
314f70fd DW	229	spin_unlock(&task_capability_lock);
1da177e4	230
314f70fd	231	return ret;
1da177e4	232	}
12b5989b CW	233
	234	int __capable(struct task_struct *t, int cap)
	235	{
	236	if (security_capable(t, cap) == 0) {
	237	t->flags \|= PF_SUPERPRIV;
	238	return 1;
	239	}
	240	return 0;
	241	}
12b5989b CW	242
	243	int capable(int cap)
	244	{
	245	return __capable(current, cap);
	246	}
	247	EXPORT_SYMBOL(capable);