[GitHub/mt8127/android_kernel_alcatel_ttab.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);

/*
 * Leveraged for setting/resetting capabilities
 */

const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
const kernel_cap_t __cap_full_set = CAP_FULL_SET;
const kernel_cap_t __cap_init_eff_set = CAP_INIT_EFF_SET;

EXPORT_SYMBOL(__cap_empty_set);
EXPORT_SYMBOL(__cap_full_set);
EXPORT_SYMBOL(__cap_init_eff_set);

/*
 * More recent versions of libcap are available from:
 *
 *   http://www.kernel.org/pub/linux/libs/security/linux-privs/
 */

static void warn_legacy_capability_use(void)
{
	static int warned;
	if (!warned) {
		char name[sizeof(current->comm)];

		printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
		       " (legacy support in use)\n",
		       get_task_comm(name, current));
		warned = 1;
	}
}

/*
 * 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;
	unsigned tocopy;
	kernel_cap_t pE, pI, pP;

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

	switch (version) {
	case _LINUX_CAPABILITY_VERSION_1:
		warn_legacy_capability_use();
		tocopy = _LINUX_CAPABILITY_U32S_1;
		break;
	case _LINUX_CAPABILITY_VERSION_2:
		tocopy = _LINUX_CAPABILITY_U32S_2;
		break;
	default:
		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, &pE, &pI, &pP);

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

	if (!ret) {
		struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
		unsigned i;

		for (i = 0; i < tocopy; i++) {
			kdata[i].effective = pE.cap[i];
			kdata[i].permitted = pP.cap[i];
			kdata[i].inheritable = pI.cap[i];
		}

		/*
		 * Note, in the case, tocopy < _LINUX_CAPABILITY_U32S,
		 * we silently drop the upper capabilities here. This
		 * has the effect of making older libcap
		 * implementations implicitly drop upper capability
		 * bits when they perform a: capget/modify/capset
		 * sequence.
		 *
		 * This behavior is considered fail-safe
		 * behavior. Upgrading the application to a newer
		 * version of libcap will enable access to the newer
		 * capabilities.
		 *
		 * An alternative would be to return an error here
		 * (-ERANGE), but that causes legacy applications to
		 * unexpectidly fail; the capget/modify/capset aborts
		 * before modification is attempted and the application
		 * fails.
		 */

		if (copy_to_user(dataptr, kdata, tocopy
				 * sizeof(struct __user_cap_data_struct))) {
			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)
{
	struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
	unsigned i, tocopy;
	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;

	switch (version) {
	case _LINUX_CAPABILITY_VERSION_1:
		warn_legacy_capability_use();
		tocopy = _LINUX_CAPABILITY_U32S_1;
		break;
	case _LINUX_CAPABILITY_VERSION_2:
		tocopy = _LINUX_CAPABILITY_U32S_2;
		break;
	default:
		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(&kdata, data, tocopy
			   * sizeof(struct __user_cap_data_struct))) {
		return -EFAULT;
	}

	for (i = 0; i < tocopy; i++) {
		effective.cap[i] = kdata[i].effective;
		permitted.cap[i] = kdata[i].permitted;
		inheritable.cap[i] = kdata[i].inheritable;
	}
	while (i < _LINUX_CAPABILITY_U32S) {
		effective.cap[i] = 0;
		permitted.cap[i] = 0;
		inheritable.cap[i] = 0;
		i++;
	}

	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
e338d263 AM	24	/*
	25	* Leveraged for setting/resetting capabilities
	26	*/
	27
	28	const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
	29	const kernel_cap_t __cap_full_set = CAP_FULL_SET;
	30	const kernel_cap_t __cap_init_eff_set = CAP_INIT_EFF_SET;
	31
	32	EXPORT_SYMBOL(__cap_empty_set);
	33	EXPORT_SYMBOL(__cap_full_set);
	34	EXPORT_SYMBOL(__cap_init_eff_set);
	35
	36	/*
	37	* More recent versions of libcap are available from:
	38	*
	39	* http://www.kernel.org/pub/linux/libs/security/linux-privs/
	40	*/
	41
	42	static void warn_legacy_capability_use(void)
	43	{
	44	static int warned;
	45	if (!warned) {
	46	char name[sizeof(current->comm)];
	47
	48	printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
	49	" (legacy support in use)\n",
	50	get_task_comm(name, current));
	51	warned = 1;
	52	}
	53	}
	54
1da177e4 LT	55	/*
	56	* For sys_getproccap() and sys_setproccap(), any of the three
	57	* capability set pointers may be NULL -- indicating that that set is
	58	* uninteresting and/or not to be changed.
	59	*/
	60
207a7ba8	61	/**
1da177e4	62	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	63	* @header: pointer to struct that contains capability version and
	64	* target pid data
	65	* @dataptr: pointer to struct that contains the effective, permitted,
	66	* and inheritable capabilities that are returned
	67	*
	68	* Returns 0 on success and < 0 on error.
1da177e4 LT	69	*/
	70	asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
	71	{
314f70fd DW	72	int ret = 0;
	73	pid_t pid;
	74	__u32 version;
	75	struct task_struct *target;
e338d263 AM	76	unsigned tocopy;
e338d263 AM	77	kernel_cap_t pE, pI, pP;
314f70fd DW	78
	79	if (get_user(version, &header->version))
	80	return -EFAULT;
	81
e338d263 AM	82	switch (version) {
	83	case _LINUX_CAPABILITY_VERSION_1:
	84	warn_legacy_capability_use();
	85	tocopy = _LINUX_CAPABILITY_U32S_1;
	86	break;
	87	case _LINUX_CAPABILITY_VERSION_2:
	88	tocopy = _LINUX_CAPABILITY_U32S_2;
	89	break;
	90	default:
314f70fd DW	91	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	92	return -EFAULT;
	93	return -EINVAL;
	94	}
1da177e4	95
314f70fd DW	96	if (get_user(pid, &header->pid))
314f70fd DW	97	return -EFAULT;
1da177e4	98
314f70fd DW	99	if (pid < 0)
314f70fd DW	100	return -EINVAL;
1da177e4	101
314f70fd DW	102	spin_lock(&task_capability_lock);
314f70fd DW	103	read_lock(&tasklist_lock);
1da177e4	104
b488893a	105	if (pid && pid != task_pid_vnr(current)) {
228ebcbe	106	target = find_task_by_vpid(pid);
314f70fd DW	107	if (!target) {
	108	ret = -ESRCH;
	109	goto out;
	110	}
	111	} else
	112	target = current;
1da177e4	113
e338d263	114	ret = security_capget(target, &pE, &pI, &pP);
1da177e4 LT	115
1da177e4 LT	116	out:
314f70fd DW	117	read_unlock(&tasklist_lock);
314f70fd DW	118	spin_unlock(&task_capability_lock);
1da177e4	119
e338d263 AM	120	if (!ret) {
	121	struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
	122	unsigned i;
	123
	124	for (i = 0; i < tocopy; i++) {
	125	kdata[i].effective = pE.cap[i];
	126	kdata[i].permitted = pP.cap[i];
	127	kdata[i].inheritable = pI.cap[i];
	128	}
	129
	130	/*
	131	* Note, in the case, tocopy < _LINUX_CAPABILITY_U32S,
	132	* we silently drop the upper capabilities here. This
	133	* has the effect of making older libcap
	134	* implementations implicitly drop upper capability
	135	* bits when they perform a: capget/modify/capset
	136	* sequence.
	137	*
	138	* This behavior is considered fail-safe
	139	* behavior. Upgrading the application to a newer
	140	* version of libcap will enable access to the newer
	141	* capabilities.
	142	*
	143	* An alternative would be to return an error here
	144	* (-ERANGE), but that causes legacy applications to
	145	* unexpectidly fail; the capget/modify/capset aborts
	146	* before modification is attempted and the application
	147	* fails.
	148	*/
	149
	150	if (copy_to_user(dataptr, kdata, tocopy
	151	* sizeof(struct __user_cap_data_struct))) {
	152	return -EFAULT;
	153	}
	154	}
1da177e4	155
314f70fd	156	return ret;
1da177e4 LT	157	}
	158
	159	/*
	160	* cap_set_pg - set capabilities for all processes in a given process
	161	* group. We call this holding task_capability_lock and tasklist_lock.
	162	*/
41487c65	163	static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
1da177e4 LT	164	kernel_cap_t *inheritable,
	165	kernel_cap_t *permitted)
	166	{
36c8b586	167	struct task_struct g, target;
1da177e4 LT	168	int ret = -EPERM;
1da177e4 LT	169	int found = 0;
41487c65	170	struct pid *pgrp;
1da177e4	171
8990571e	172	pgrp = find_vpid(pgrp_nr);
41487c65	173	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
1da177e4 LT	174	target = g;
	175	while_each_thread(g, target) {
	176	if (!security_capset_check(target, effective,
	177	inheritable,
	178	permitted)) {
	179	security_capset_set(target, effective,
	180	inheritable,
	181	permitted);
	182	ret = 0;
	183	}
	184	found = 1;
	185	}
41487c65	186	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);
1da177e4 LT	187
1da177e4 LT	188	if (!found)
314f70fd	189	ret = 0;
1da177e4 LT	190	return ret;
	191	}
	192
	193	/*
	194	* cap_set_all - set capabilities for all processes other than init
	195	* and self. We call this holding task_capability_lock and tasklist_lock.
	196	*/
	197	static inline int cap_set_all(kernel_cap_t *effective,
	198	kernel_cap_t *inheritable,
	199	kernel_cap_t *permitted)
	200	{
36c8b586	201	struct task_struct g, target;
1da177e4 LT	202	int ret = -EPERM;
	203	int found = 0;
	204
	205	do_each_thread(g, target) {
b460cbc5	206	if (target == current \|\| is_container_init(target->group_leader))
1da177e4 LT	207	continue;
	208	found = 1;
	209	if (security_capset_check(target, effective, inheritable,
	210	permitted))
	211	continue;
	212	ret = 0;
	213	security_capset_set(target, effective, inheritable, permitted);
	214	} while_each_thread(g, target);
	215
	216	if (!found)
	217	ret = 0;
	218	return ret;
	219	}
	220
207a7ba8 RD	221	/**
	222	* sys_capset - set capabilities for a process or a group of processes
	223	* @header: pointer to struct that contains capability version and
	224	* target pid data
	225	* @data: pointer to struct that contains the effective, permitted,
	226	* and inheritable capabilities
	227	*
	228	* Set capabilities for a given process, all processes, or all
1da177e4 LT	229	* processes in a given process group.
	230	*
	231	* The restrictions on setting capabilities are specified as:
	232	*
	233	* [pid is for the 'target' task. 'current' is the calling task.]
	234	*
	235	* I: any raised capabilities must be a subset of the (old current) permitted
	236	* P: any raised capabilities must be a subset of the (old current) permitted
	237	* E: must be set to a subset of (new target) permitted
207a7ba8 RD	238	*
207a7ba8 RD	239	* Returns 0 on success and < 0 on error.
1da177e4 LT	240	*/
	241	asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
	242	{
e338d263 AM	243	struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
e338d263 AM	244	unsigned i, tocopy;
314f70fd DW	245	kernel_cap_t inheritable, permitted, effective;
	246	__u32 version;
	247	struct task_struct *target;
	248	int ret;
	249	pid_t pid;
	250
	251	if (get_user(version, &header->version))
	252	return -EFAULT;
	253
e338d263 AM	254	switch (version) {
	255	case _LINUX_CAPABILITY_VERSION_1:
	256	warn_legacy_capability_use();
	257	tocopy = _LINUX_CAPABILITY_U32S_1;
	258	break;
	259	case _LINUX_CAPABILITY_VERSION_2:
	260	tocopy = _LINUX_CAPABILITY_U32S_2;
	261	break;
	262	default:
314f70fd DW	263	if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
	264	return -EFAULT;
	265	return -EINVAL;
	266	}
	267
	268	if (get_user(pid, &header->pid))
	269	return -EFAULT;
	270
b488893a	271	if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
314f70fd DW	272	return -EPERM;
314f70fd DW	273
e338d263 AM	274	if (copy_from_user(&kdata, data, tocopy
e338d263 AM	275	* sizeof(struct __user_cap_data_struct))) {
314f70fd	276	return -EFAULT;
e338d263 AM	277	}
	278
	279	for (i = 0; i < tocopy; i++) {
	280	effective.cap[i] = kdata[i].effective;
	281	permitted.cap[i] = kdata[i].permitted;
	282	inheritable.cap[i] = kdata[i].inheritable;
	283	}
	284	while (i < _LINUX_CAPABILITY_U32S) {
	285	effective.cap[i] = 0;
	286	permitted.cap[i] = 0;
	287	inheritable.cap[i] = 0;
	288	i++;
	289	}
314f70fd DW	290
	291	spin_lock(&task_capability_lock);
	292	read_lock(&tasklist_lock);
	293
b488893a	294	if (pid > 0 && pid != task_pid_vnr(current)) {
228ebcbe	295	target = find_task_by_vpid(pid);
314f70fd DW	296	if (!target) {
	297	ret = -ESRCH;
	298	goto out;
	299	}
	300	} else
	301	target = current;
	302
	303	ret = 0;
	304
	305	/* having verified that the proposed changes are legal,
	306	we now put them into effect. */
	307	if (pid < 0) {
	308	if (pid == -1) /* all procs other than current and init */
	309	ret = cap_set_all(&effective, &inheritable, &permitted);
	310
	311	else /* all procs in process group */
	312	ret = cap_set_pg(-pid, &effective, &inheritable,
	313	&permitted);
	314	} else {
	315	ret = security_capset_check(target, &effective, &inheritable,
	316	&permitted);
	317	if (!ret)
	318	security_capset_set(target, &effective, &inheritable,
	319	&permitted);
	320	}
1da177e4 LT	321
1da177e4 LT	322	out:
314f70fd DW	323	read_unlock(&tasklist_lock);
314f70fd DW	324	spin_unlock(&task_capability_lock);
1da177e4	325
314f70fd	326	return ret;
1da177e4	327	}
12b5989b CW	328
	329	int __capable(struct task_struct *t, int cap)
	330	{
	331	if (security_capable(t, cap) == 0) {
	332	t->flags \|= PF_SUPERPRIV;
	333	return 1;
	334	}
	335	return 0;
	336	}
12b5989b CW	337
	338	int capable(int cap)
	339	{
	340	return __capable(current, cap);
	341	}
	342	EXPORT_SYMBOL(capable);