[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;
	}
}

/*
 * Version 2 capabilities worked fine, but the linux/capability.h file
 * that accompanied their introduction encouraged their use without
 * the necessary user-space source code changes. As such, we have
 * created a version 3 with equivalent functionality to version 2, but
 * with a header change to protect legacy source code from using
 * version 2 when it wanted to use version 1. If your system has code
 * that trips the following warning, it is using version 2 specific
 * capabilities and may be doing so insecurely.
 *
 * The remedy is to either upgrade your version of libcap (to 2.10+,
 * if the application is linked against it), or recompile your
 * application with modern kernel headers and this warning will go
 * away.
 */

static void warn_deprecated_v2(void)
{
	static int warned;

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

		printk(KERN_INFO "warning: `%s' uses deprecated v2"
		       " capabilities in a way that may be insecure.\n",
		       get_task_comm(name, current));
		warned = 1;
	}
}

/*
 * Version check. Return the number of u32s in each capability flag
 * array, or a negative value on error.
 */
static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
{
	__u32 version;

	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:
		warn_deprecated_v2();
		/*
		 * fall through - v3 is otherwise equivalent to v2.
		 */
	case _LINUX_CAPABILITY_VERSION_3:
		*tocopy = _LINUX_CAPABILITY_U32S_3;
		break;
	default:
		if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
			return -EFAULT;
		return -EINVAL;
	}

	return 0;
}

#ifndef CONFIG_SECURITY_FILE_CAPABILITIES

/*
 * Without filesystem capability support, we nominally support one process
 * setting the capabilities of another
 */
static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
				     kernel_cap_t *pIp, kernel_cap_t *pPp)
{
	struct task_struct *target;
	int ret;

	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, pEp, pIp, pPp);

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

	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;

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

	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);

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

	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;

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

	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);

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

	if (!found)
		ret = 0;

	return ret;
}

/*
 * Given the target pid does not refer to the current process we
 * need more elaborate support... (This support is not present when
 * filesystem capabilities are configured.)
 */
static inline int do_sys_capset_other_tasks(pid_t pid, kernel_cap_t *effective,
					    kernel_cap_t *inheritable,
					    kernel_cap_t *permitted)
{
	struct task_struct *target;
	int ret;

	if (!capable(CAP_SETPCAP))
		return -EPERM;

	if (pid == -1)	          /* all procs other than current and init */
		return cap_set_all(effective, inheritable, permitted);

	else if (pid < 0)                    /* all procs in process group */
		return cap_set_pg(-pid, effective, inheritable, permitted);

	/* target != current */
	spin_lock(&task_capability_lock);
	read_lock(&tasklist_lock);

	target = find_task_by_vpid(pid);
	if (!target)
		ret = -ESRCH;
	else {
		ret = security_capset_check(target, effective, inheritable,
					    permitted);

		/* having verified that the proposed changes are legal,
		   we now put them into effect. */
		if (!ret)
			security_capset_set(target, effective, inheritable,
					    permitted);
	}

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

	return ret;
}

#else /* ie., def CONFIG_SECURITY_FILE_CAPABILITIES */

/*
 * If we have configured with filesystem capability support, then the
 * only thing that can change the capabilities of the current process
 * is the current process. As such, we can't be in this code at the
 * same time as we are in the process of setting capabilities in this
 * process. The net result is that we can limit our use of locks to
 * when we are reading the caps of another process.
 */
static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
				     kernel_cap_t *pIp, kernel_cap_t *pPp)
{
	int ret;

	if (pid && (pid != task_pid_vnr(current))) {
		struct task_struct *target;

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

		target = find_task_by_vpid(pid);
		if (!target)
			ret = -ESRCH;
		else
			ret = security_capget(target, pEp, pIp, pPp);

		read_unlock(&tasklist_lock);
		spin_unlock(&task_capability_lock);
	} else
		ret = security_capget(current, pEp, pIp, pPp);

	return ret;
}

/*
 * With filesystem capability support configured, the kernel does not
 * permit the changing of capabilities in one process by another
 * process. (CAP_SETPCAP has much less broad semantics when configured
 * this way.)
 */
static inline int do_sys_capset_other_tasks(pid_t pid,
					    kernel_cap_t *effective,
					    kernel_cap_t *inheritable,
					    kernel_cap_t *permitted)
{
	return -EPERM;
}

#endif /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */

/*
 * Atomically modify the effective capabilities returning the original
 * value. No permission check is performed here - it is assumed that the
 * caller is permitted to set the desired effective capabilities.
 */
kernel_cap_t cap_set_effective(const kernel_cap_t pE_new)
{
	kernel_cap_t pE_old;

	spin_lock(&task_capability_lock);

	pE_old = current->cap_effective;
	current->cap_effective = pE_new;

	spin_unlock(&task_capability_lock);

	return pE_old;
}

EXPORT_SYMBOL(cap_set_effective);

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

	ret = cap_validate_magic(header, &tocopy);
	if (ret != 0)
		return ret;

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

	if (pid < 0)
		return -EINVAL;

	ret = cap_get_target_pid(pid, &pE, &pI, &pP);

	if (!ret) {
		struct __user_cap_data_struct kdata[_KERNEL_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 < _KERNEL_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;
}

/**
 * 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[_KERNEL_CAPABILITY_U32S];
	unsigned i, tocopy;
	kernel_cap_t inheritable, permitted, effective;
	int ret;
	pid_t pid;

	ret = cap_validate_magic(header, &tocopy);
	if (ret != 0)
		return ret;

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

	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 < _KERNEL_CAPABILITY_U32S) {
		effective.cap[i] = 0;
		permitted.cap[i] = 0;
		inheritable.cap[i] = 0;
		i++;
	}

	if (pid && (pid != task_pid_vnr(current)))
		ret = do_sys_capset_other_tasks(pid, &effective, &inheritable,
						&permitted);
	else {
		/*
		 * This lock is required even when filesystem
		 * capability support is configured - it protects the
		 * sys_capget() call from returning incorrect data in
		 * the case that the targeted process is not the
		 * current one.
		 */
		spin_lock(&task_capability_lock);

		ret = security_capset_check(current, &effective, &inheritable,
					    &permitted);
		/*
		 * Having verified that the proposed changes are
		 * legal, we now put them into effect.
		 */
		if (!ret)
			security_capset_set(current, &effective, &inheritable,
					    &permitted);
		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
ca05a99a AM	55	/*
	56	* Version 2 capabilities worked fine, but the linux/capability.h file
	57	* that accompanied their introduction encouraged their use without
	58	* the necessary user-space source code changes. As such, we have
	59	* created a version 3 with equivalent functionality to version 2, but
	60	* with a header change to protect legacy source code from using
	61	* version 2 when it wanted to use version 1. If your system has code
	62	* that trips the following warning, it is using version 2 specific
	63	* capabilities and may be doing so insecurely.
	64	*
	65	* The remedy is to either upgrade your version of libcap (to 2.10+,
	66	* if the application is linked against it), or recompile your
	67	* application with modern kernel headers and this warning will go
	68	* away.
	69	*/
	70
	71	static void warn_deprecated_v2(void)
	72	{
	73	static int warned;
	74
	75	if (!warned) {
	76	char name[sizeof(current->comm)];
	77
	78	printk(KERN_INFO "warning: `%s' uses deprecated v2"
	79	" capabilities in a way that may be insecure.\n",
	80	get_task_comm(name, current));
	81	warned = 1;
	82	}
	83	}
	84
	85	/*
	86	* Version check. Return the number of u32s in each capability flag
	87	* array, or a negative value on error.
	88	*/
	89	static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
	90	{
	91	__u32 version;
	92
	93	if (get_user(version, &header->version))
	94	return -EFAULT;
	95
	96	switch (version) {
	97	case _LINUX_CAPABILITY_VERSION_1:
	98	warn_legacy_capability_use();
	99	*tocopy = _LINUX_CAPABILITY_U32S_1;
	100	break;
	101	case _LINUX_CAPABILITY_VERSION_2:
	102	warn_deprecated_v2();
	103	/*
	104	* fall through - v3 is otherwise equivalent to v2.
	105	*/
	106	case _LINUX_CAPABILITY_VERSION_3:
	107	*tocopy = _LINUX_CAPABILITY_U32S_3;
	108	break;
	109	default:
	110	if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
	111	return -EFAULT;
	112	return -EINVAL;
	113	}
	114
	115	return 0;
	116	}
	117
ab763c71 AM	118	#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
	119
	120	/*
	121	* Without filesystem capability support, we nominally support one process
	122	* setting the capabilities of another
	123	*/
	124	static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
	125	kernel_cap_t pIp, kernel_cap_t pPp)
	126	{
	127	struct task_struct *target;
	128	int ret;
	129
	130	spin_lock(&task_capability_lock);
	131	read_lock(&tasklist_lock);
	132
	133	if (pid && pid != task_pid_vnr(current)) {
	134	target = find_task_by_vpid(pid);
	135	if (!target) {
	136	ret = -ESRCH;
	137	goto out;
	138	}
	139	} else
	140	target = current;
	141
	142	ret = security_capget(target, pEp, pIp, pPp);
	143
	144	out:
	145	read_unlock(&tasklist_lock);
	146	spin_unlock(&task_capability_lock);
	147
	148	return ret;
	149	}
	150
	151	/*
	152	* cap_set_pg - set capabilities for all processes in a given process
	153	* group. We call this holding task_capability_lock and tasklist_lock.
	154	*/
	155	static inline int cap_set_pg(int pgrp_nr, kernel_cap_t *effective,
	156	kernel_cap_t *inheritable,
	157	kernel_cap_t *permitted)
	158	{
	159	struct task_struct g, target;
	160	int ret = -EPERM;
	161	int found = 0;
	162	struct pid *pgrp;
	163
	164	spin_lock(&task_capability_lock);
	165	read_lock(&tasklist_lock);
	166
	167	pgrp = find_vpid(pgrp_nr);
	168	do_each_pid_task(pgrp, PIDTYPE_PGID, g) {
	169	target = g;
	170	while_each_thread(g, target) {
	171	if (!security_capset_check(target, effective,
	172	inheritable, permitted)) {
	173	security_capset_set(target, effective,
	174	inheritable, permitted);
	175	ret = 0;
	176	}
	177	found = 1;
	178	}
	179	} while_each_pid_task(pgrp, PIDTYPE_PGID, g);
	180
	181	read_unlock(&tasklist_lock);
182	spin_unlock(&task_capability_lock);
183
184	if (!found)
185	ret = 0;
186	return ret;
187	}
188
1da177e4	189	/*
ab763c71 AM	190	* cap_set_all - set capabilities for all processes other than init
ab763c71 AM	191	* and self. We call this holding task_capability_lock and tasklist_lock.
1da177e4	192	*/
ab763c71 AM	193	static inline int cap_set_all(kernel_cap_t *effective,
	194	kernel_cap_t *inheritable,
	195	kernel_cap_t *permitted)
	196	{
	197	struct task_struct g, target;
	198	int ret = -EPERM;
	199	int found = 0;
	200
	201	spin_lock(&task_capability_lock);
	202	read_lock(&tasklist_lock);
	203
	204	do_each_thread(g, target) {
	205	if (target == current
	206	\|\| is_container_init(target->group_leader))
	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	read_unlock(&tasklist_lock);
	217	spin_unlock(&task_capability_lock);
	218
	219	if (!found)
	220	ret = 0;
	221
	222	return ret;
	223	}
	224
	225	/*
	226	* Given the target pid does not refer to the current process we
	227	* need more elaborate support... (This support is not present when
	228	* filesystem capabilities are configured.)
	229	*/
	230	static inline int do_sys_capset_other_tasks(pid_t pid, kernel_cap_t *effective,
	231	kernel_cap_t *inheritable,
	232	kernel_cap_t *permitted)
	233	{
	234	struct task_struct *target;
	235	int ret;
	236
	237	if (!capable(CAP_SETPCAP))
	238	return -EPERM;
	239
	240	if (pid == -1) /* all procs other than current and init */
	241	return cap_set_all(effective, inheritable, permitted);
	242
	243	else if (pid < 0) /* all procs in process group */
	244	return cap_set_pg(-pid, effective, inheritable, permitted);
	245
	246	/* target != current */
	247	spin_lock(&task_capability_lock);
	248	read_lock(&tasklist_lock);
	249
	250	target = find_task_by_vpid(pid);
	251	if (!target)
	252	ret = -ESRCH;
	253	else {
	254	ret = security_capset_check(target, effective, inheritable,
	255	permitted);
	256
257	/* having verified that the proposed changes are legal,
258	we now put them into effect. */
259	if (!ret)
260	security_capset_set(target, effective, inheritable,
261	permitted);
262	}
263
264	read_unlock(&tasklist_lock);
265	spin_unlock(&task_capability_lock);
266
267	return ret;
268	}
269
270	#else /* ie., def CONFIG_SECURITY_FILE_CAPABILITIES */
271
272	/*
273	* If we have configured with filesystem capability support, then the
274	* only thing that can change the capabilities of the current process
275	* is the current process. As such, we can't be in this code at the
276	* same time as we are in the process of setting capabilities in this
277	* process. The net result is that we can limit our use of locks to
278	* when we are reading the caps of another process.
279	*/
280	static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
281	kernel_cap_t pIp, kernel_cap_t pPp)
282	{
283	int ret;
284
285	if (pid && (pid != task_pid_vnr(current))) {
286	struct task_struct *target;
287
288	spin_lock(&task_capability_lock);
289	read_lock(&tasklist_lock);
290
291	target = find_task_by_vpid(pid);
292	if (!target)
293	ret = -ESRCH;
294	else
295	ret = security_capget(target, pEp, pIp, pPp);
296
297	read_unlock(&tasklist_lock);
298	spin_unlock(&task_capability_lock);
299	} else
300	ret = security_capget(current, pEp, pIp, pPp);
301
302	return ret;
303	}
304
305	/*
306	* With filesystem capability support configured, the kernel does not
307	* permit the changing of capabilities in one process by another
308	* process. (CAP_SETPCAP has much less broad semantics when configured
309	* this way.)
310	*/
311	static inline int do_sys_capset_other_tasks(pid_t pid,
312	kernel_cap_t *effective,
313	kernel_cap_t *inheritable,
314	kernel_cap_t *permitted)
315	{
316	return -EPERM;
317	}
318
319	#endif /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
1da177e4	320
086f7316 AM	321	/*
	322	* Atomically modify the effective capabilities returning the original
	323	* value. No permission check is performed here - it is assumed that the
	324	* caller is permitted to set the desired effective capabilities.
	325	*/
	326	kernel_cap_t cap_set_effective(const kernel_cap_t pE_new)
	327	{
	328	kernel_cap_t pE_old;
	329
	330	spin_lock(&task_capability_lock);
	331
	332	pE_old = current->cap_effective;
	333	current->cap_effective = pE_new;
	334
	335	spin_unlock(&task_capability_lock);
	336
	337	return pE_old;
	338	}
	339
	340	EXPORT_SYMBOL(cap_set_effective);
	341
207a7ba8	342	/**
1da177e4	343	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	344	* @header: pointer to struct that contains capability version and
	345	* target pid data
	346	* @dataptr: pointer to struct that contains the effective, permitted,
	347	* and inheritable capabilities that are returned
	348	*
	349	* Returns 0 on success and < 0 on error.
1da177e4 LT	350	*/
	351	asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
	352	{
314f70fd DW	353	int ret = 0;
314f70fd DW	354	pid_t pid;
e338d263 AM	355	unsigned tocopy;
e338d263 AM	356	kernel_cap_t pE, pI, pP;
314f70fd	357
ca05a99a AM	358	ret = cap_validate_magic(header, &tocopy);
	359	if (ret != 0)
	360	return ret;
1da177e4	361
314f70fd DW	362	if (get_user(pid, &header->pid))
314f70fd DW	363	return -EFAULT;
1da177e4	364
314f70fd DW	365	if (pid < 0)
314f70fd DW	366	return -EINVAL;
1da177e4	367
ab763c71	368	ret = cap_get_target_pid(pid, &pE, &pI, &pP);
1da177e4	369
e338d263	370	if (!ret) {
ca05a99a	371	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
e338d263 AM	372	unsigned i;
	373
	374	for (i = 0; i < tocopy; i++) {
	375	kdata[i].effective = pE.cap[i];
	376	kdata[i].permitted = pP.cap[i];
	377	kdata[i].inheritable = pI.cap[i];
	378	}
	379
	380	/*
ca05a99a	381	* Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
e338d263 AM	382	* we silently drop the upper capabilities here. This
	383	* has the effect of making older libcap
	384	* implementations implicitly drop upper capability
	385	* bits when they perform a: capget/modify/capset
	386	* sequence.
	387	*
	388	* This behavior is considered fail-safe
	389	* behavior. Upgrading the application to a newer
	390	* version of libcap will enable access to the newer
	391	* capabilities.
	392	*
	393	* An alternative would be to return an error here
	394	* (-ERANGE), but that causes legacy applications to
	395	* unexpectidly fail; the capget/modify/capset aborts
	396	* before modification is attempted and the application
	397	* fails.
	398	*/
e338d263 AM	399	if (copy_to_user(dataptr, kdata, tocopy
	400	* sizeof(struct __user_cap_data_struct))) {
	401	return -EFAULT;
	402	}
	403	}
1da177e4	404
314f70fd	405	return ret;
1da177e4 LT	406	}
1da177e4 LT	407
207a7ba8	408	/**
ab763c71	409	* sys_capset - set capabilities for a process or (*) a group of processes
207a7ba8 RD	410	* @header: pointer to struct that contains capability version and
	411	* target pid data
	412	* @data: pointer to struct that contains the effective, permitted,
	413	* and inheritable capabilities
	414	*
	415	* Set capabilities for a given process, all processes, or all
1da177e4 LT	416	* processes in a given process group.
	417	*
	418	* The restrictions on setting capabilities are specified as:
	419	*
	420	* [pid is for the 'target' task. 'current' is the calling task.]
	421	*
	422	* I: any raised capabilities must be a subset of the (old current) permitted
	423	* P: any raised capabilities must be a subset of the (old current) permitted
	424	* E: must be set to a subset of (new target) permitted
207a7ba8 RD	425	*
207a7ba8 RD	426	* Returns 0 on success and < 0 on error.
1da177e4 LT	427	*/
	428	asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
	429	{
ca05a99a	430	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
e338d263	431	unsigned i, tocopy;
314f70fd	432	kernel_cap_t inheritable, permitted, effective;
314f70fd DW	433	int ret;
	434	pid_t pid;
	435
ca05a99a AM	436	ret = cap_validate_magic(header, &tocopy);
	437	if (ret != 0)
	438	return ret;
314f70fd DW	439
	440	if (get_user(pid, &header->pid))
	441	return -EFAULT;
	442
e338d263 AM	443	if (copy_from_user(&kdata, data, tocopy
e338d263 AM	444	* sizeof(struct __user_cap_data_struct))) {
314f70fd	445	return -EFAULT;
e338d263 AM	446	}
	447
	448	for (i = 0; i < tocopy; i++) {
	449	effective.cap[i] = kdata[i].effective;
	450	permitted.cap[i] = kdata[i].permitted;
	451	inheritable.cap[i] = kdata[i].inheritable;
	452	}
ca05a99a	453	while (i < _KERNEL_CAPABILITY_U32S) {
e338d263 AM	454	effective.cap[i] = 0;
	455	permitted.cap[i] = 0;
	456	inheritable.cap[i] = 0;
	457	i++;
	458	}
314f70fd	459
ab763c71 AM	460	if (pid && (pid != task_pid_vnr(current)))
	461	ret = do_sys_capset_other_tasks(pid, &effective, &inheritable,
	462	&permitted);
	463	else {
	464	/*
	465	* This lock is required even when filesystem
	466	* capability support is configured - it protects the
	467	* sys_capget() call from returning incorrect data in
	468	* the case that the targeted process is not the
	469	* current one.
	470	*/
	471	spin_lock(&task_capability_lock);
314f70fd	472
ab763c71	473	ret = security_capset_check(current, &effective, &inheritable,
314f70fd	474	&permitted);
ab763c71 AM	475	/*
	476	* Having verified that the proposed changes are
	477	* legal, we now put them into effect.
	478	*/
314f70fd	479	if (!ret)
ab763c71	480	security_capset_set(current, &effective, &inheritable,
314f70fd	481	&permitted);
ab763c71	482	spin_unlock(&task_capability_lock);
314f70fd	483	}
1da177e4	484
1da177e4	485
314f70fd	486	return ret;
1da177e4	487	}
12b5989b CW	488
	489	int __capable(struct task_struct *t, int cap)
	490	{
	491	if (security_capable(t, cap) == 0) {
	492	t->flags \|= PF_SUPERPRIV;
	493	return 1;
	494	}
	495	return 0;
	496	}
12b5989b CW	497
	498	int capable(int cap)
	499	{
	500	return __capable(current, cap);
	501	}
	502	EXPORT_SYMBOL(capable);