[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@transmeta.com>
 * 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 <asm/uaccess.h>

unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
kernel_cap_t cap_bset = CAP_INIT_EFF_SET;

EXPORT_SYMBOL(securebits);
EXPORT_SYMBOL(cap_bset);

/*
 * 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 != current->pid) {
	     target = find_task_by_pid(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_pid(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_init(target))
                     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 != current->pid && !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 != current->pid) {
          target = find_task_by_pid(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;
}
EXPORT_SYMBOL(__capable);

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	*
	6	* Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com>
	7	* 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
	8	*/
	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>
	15	#include <asm/uaccess.h>
	16
	17	unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
	18	kernel_cap_t cap_bset = CAP_INIT_EFF_SET;
	19
	20	EXPORT_SYMBOL(securebits);
	21	EXPORT_SYMBOL(cap_bset);
	22
	23	/*
	24	* This lock protects task->cap_* for all tasks including current.
	25	* Locking rule: acquire this prior to tasklist_lock.
	26	*/
	27	static DEFINE_SPINLOCK(task_capability_lock);
	28
	29	/*
	30	* For sys_getproccap() and sys_setproccap(), any of the three
	31	* capability set pointers may be NULL -- indicating that that set is
	32	* uninteresting and/or not to be changed.
	33	*/
	34
207a7ba8	35	/**
1da177e4	36	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	37	* @header: pointer to struct that contains capability version and
	38	* target pid data
	39	* @dataptr: pointer to struct that contains the effective, permitted,
	40	* and inheritable capabilities that are returned
	41	*
	42	* Returns 0 on success and < 0 on error.
1da177e4 LT	43	*/
	44	asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
	45	{
	46	int ret = 0;
	47	pid_t pid;
	48	__u32 version;
36c8b586	49	struct task_struct *target;
1da177e4 LT	50	struct __user_cap_data_struct data;
	51
	52	if (get_user(version, &header->version))
	53	return -EFAULT;
	54
	55	if (version != _LINUX_CAPABILITY_VERSION) {
	56	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	57	return -EFAULT;
	58	return -EINVAL;
	59	}
	60
	61	if (get_user(pid, &header->pid))
	62	return -EFAULT;
	63
	64	if (pid < 0)
	65	return -EINVAL;
	66
	67	spin_lock(&task_capability_lock);
	68	read_lock(&tasklist_lock);
	69
	70	if (pid && pid != current->pid) {
	71	target = find_task_by_pid(pid);
	72	if (!target) {
	73	ret = -ESRCH;
	74	goto out;
	75	}
	76	} else
	77	target = current;
	78
	79	ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted);
	80
	81	out:
	82	read_unlock(&tasklist_lock);
	83	spin_unlock(&task_capability_lock);
	84
	85	if (!ret && copy_to_user(dataptr, &data, sizeof data))
	86	return -EFAULT;
	87
	88	return ret;
	89	}
	90
	91	/*
	92	* cap_set_pg - set capabilities for all processes in a given process
	93	* group. We call this holding task_capability_lock and tasklist_lock.
	94	*/
41487c65	95	static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
1da177e4 LT	96	kernel_cap_t *inheritable,
	97	kernel_cap_t *permitted)
	98	{
36c8b586	99	struct task_struct g, target;
1da177e4 LT	100	int ret = -EPERM;
1da177e4 LT	101	int found = 0;
41487c65	102	struct pid *pgrp;
1da177e4	103
41487c65 EB	104	pgrp = find_pid(pgrp_nr);
41487c65 EB	105	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
1da177e4 LT	106	target = g;
	107	while_each_thread(g, target) {
	108	if (!security_capset_check(target, effective,
	109	inheritable,
	110	permitted)) {
	111	security_capset_set(target, effective,
	112	inheritable,
	113	permitted);
	114	ret = 0;
	115	}
	116	found = 1;
	117	}
41487c65	118	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);
1da177e4 LT	119
	120	if (!found)
	121	ret = 0;
	122	return ret;
	123	}
	124
	125	/*
	126	* cap_set_all - set capabilities for all processes other than init
	127	* and self. We call this holding task_capability_lock and tasklist_lock.
	128	*/
	129	static inline int cap_set_all(kernel_cap_t *effective,
	130	kernel_cap_t *inheritable,
	131	kernel_cap_t *permitted)
	132	{
36c8b586	133	struct task_struct g, target;
1da177e4 LT	134	int ret = -EPERM;
	135	int found = 0;
	136
	137	do_each_thread(g, target) {
f400e198	138	if (target == current \|\| is_init(target))
1da177e4 LT	139	continue;
	140	found = 1;
	141	if (security_capset_check(target, effective, inheritable,
	142	permitted))
	143	continue;
	144	ret = 0;
	145	security_capset_set(target, effective, inheritable, permitted);
	146	} while_each_thread(g, target);
	147
	148	if (!found)
	149	ret = 0;
	150	return ret;
	151	}
	152
207a7ba8 RD	153	/**
	154	* sys_capset - set capabilities for a process or a group of processes
	155	* @header: pointer to struct that contains capability version and
	156	* target pid data
	157	* @data: pointer to struct that contains the effective, permitted,
	158	* and inheritable capabilities
	159	*
	160	* Set capabilities for a given process, all processes, or all
1da177e4 LT	161	* processes in a given process group.
	162	*
	163	* The restrictions on setting capabilities are specified as:
	164	*
	165	* [pid is for the 'target' task. 'current' is the calling task.]
	166	*
	167	* I: any raised capabilities must be a subset of the (old current) permitted
	168	* P: any raised capabilities must be a subset of the (old current) permitted
	169	* E: must be set to a subset of (new target) permitted
207a7ba8 RD	170	*
207a7ba8 RD	171	* Returns 0 on success and < 0 on error.
1da177e4 LT	172	*/
	173	asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
	174	{
	175	kernel_cap_t inheritable, permitted, effective;
	176	__u32 version;
36c8b586	177	struct task_struct *target;
1da177e4 LT	178	int ret;
	179	pid_t pid;
	180
	181	if (get_user(version, &header->version))
	182	return -EFAULT;
	183
	184	if (version != _LINUX_CAPABILITY_VERSION) {
	185	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	186	return -EFAULT;
	187	return -EINVAL;
	188	}
	189
	190	if (get_user(pid, &header->pid))
	191	return -EFAULT;
	192
	193	if (pid && pid != current->pid && !capable(CAP_SETPCAP))
	194	return -EPERM;
	195
	196	if (copy_from_user(&effective, &data->effective, sizeof(effective)) \|\|
	197	copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) \|\|
	198	copy_from_user(&permitted, &data->permitted, sizeof(permitted)))
	199	return -EFAULT;
	200
	201	spin_lock(&task_capability_lock);
	202	read_lock(&tasklist_lock);
	203
	204	if (pid > 0 && pid != current->pid) {
	205	target = find_task_by_pid(pid);
	206	if (!target) {
	207	ret = -ESRCH;
	208	goto out;
	209	}
	210	} else
	211	target = current;
	212
	213	ret = 0;
	214
	215	/* having verified that the proposed changes are legal,
	216	we now put them into effect. */
	217	if (pid < 0) {
	218	if (pid == -1) /* all procs other than current and init */
	219	ret = cap_set_all(&effective, &inheritable, &permitted);
	220
	221	else /* all procs in process group */
	222	ret = cap_set_pg(-pid, &effective, &inheritable,
	223	&permitted);
	224	} else {
	225	ret = security_capset_check(target, &effective, &inheritable,
	226	&permitted);
	227	if (!ret)
	228	security_capset_set(target, &effective, &inheritable,
	229	&permitted);
	230	}
	231
	232	out:
	233	read_unlock(&tasklist_lock);
	234	spin_unlock(&task_capability_lock);
	235
	236	return ret;
	237	}
12b5989b CW	238
	239	int __capable(struct task_struct *t, int cap)
	240	{
	241	if (security_capable(t, cap) == 0) {
	242	t->flags \|= PF_SUPERPRIV;
	243	return 1;
	244	}
	245	return 0;
	246	}
	247	EXPORT_SYMBOL(__capable);
	248
	249	int capable(int cap)
	250	{
	251	return __capable(current, cap);
	252	}
	253	EXPORT_SYMBOL(capable);