[linux.git] / kernel / capability.c

/*
 * linux/kernel/capability.c
 *
 * Copyright (C) 1997  Andrew Main <[email protected]>
 *
 * Integrated into 2.1.97+,  Andrew G. Morgan <[email protected]>
 * 30 May 2002:	Cleanup, Robert M. Love <[email protected]>
 */

#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <asm/uaccess.h>

/*
 * Leveraged for setting/resetting capabilities
 */

const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;

EXPORT_SYMBOL(__cap_empty_set);

int file_caps_enabled = 1;

static int __init file_caps_disable(char *str)
{
	file_caps_enabled = 0;
	return 1;
}
__setup("no_file_caps", file_caps_disable);

/*
 * 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;
}

/*
 * 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;

		rcu_read_lock();

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

		rcu_read_unlock();
	} else
		ret = security_capget(current, pEp, pIp, pPp);

	return ret;
}

/**
 * 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.
 */
SYSCALL_DEFINE2(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 ((dataptr == NULL) || (ret != 0))
		return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : 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 the current process only.  The ability to any other
 * process(es) has been deprecated and removed.
 *
 * The restrictions on setting capabilities are specified as:
 *
 * I: any raised capabilities must be a subset of the old permitted
 * P: any raised capabilities must be a subset of the old permitted
 * E: must be set to a subset of new permitted
 *
 * Returns 0 on success and < 0 on error.
 */
SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
{
	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
	unsigned i, tocopy, copybytes;
	kernel_cap_t inheritable, permitted, effective;
	struct cred *new;
	int ret;
	pid_t pid;

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

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

	/* may only affect current now */
	if (pid != 0 && pid != task_pid_vnr(current))
		return -EPERM;

	copybytes = tocopy * sizeof(struct __user_cap_data_struct);
	if (copybytes > sizeof(kdata))
		return -EFAULT;

	if (copy_from_user(&kdata, data, copybytes))
		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++;
	}

	new = prepare_creds();
	if (!new)
		return -ENOMEM;

	ret = security_capset(new, current_cred(),
			      &effective, &inheritable, &permitted);
	if (ret < 0)
		goto error;

	audit_log_capset(pid, new, current_cred());

	return commit_creds(new);

error:
	abort_creds(new);
	return ret;
}

/**
 * has_ns_capability - Does a task have a capability in a specific user ns
 * @t: The task in question
 * @ns: target user namespace
 * @cap: The capability to be tested for
 *
 * Return true if the specified task has the given superior capability
 * currently in effect to the specified user namespace, false if not.
 *
 * Note that this does not set PF_SUPERPRIV on the task.
 */
bool has_ns_capability(struct task_struct *t,
		       struct user_namespace *ns, int cap)
{
	int ret;

	rcu_read_lock();
	ret = security_capable(__task_cred(t), ns, cap);
	rcu_read_unlock();

	return (ret == 0);
}

/**
 * has_capability - Does a task have a capability in init_user_ns
 * @t: The task in question
 * @cap: The capability to be tested for
 *
 * Return true if the specified task has the given superior capability
 * currently in effect to the initial user namespace, false if not.
 *
 * Note that this does not set PF_SUPERPRIV on the task.
 */
bool has_capability(struct task_struct *t, int cap)
{
	return has_ns_capability(t, &init_user_ns, cap);
}

/**
 * has_ns_capability_noaudit - Does a task have a capability (unaudited)
 * in a specific user ns.
 * @t: The task in question
 * @ns: target user namespace
 * @cap: The capability to be tested for
 *
 * Return true if the specified task has the given superior capability
 * currently in effect to the specified user namespace, false if not.
 * Do not write an audit message for the check.
 *
 * Note that this does not set PF_SUPERPRIV on the task.
 */
bool has_ns_capability_noaudit(struct task_struct *t,
			       struct user_namespace *ns, int cap)
{
	int ret;

	rcu_read_lock();
	ret = security_capable_noaudit(__task_cred(t), ns, cap);
	rcu_read_unlock();

	return (ret == 0);
}

/**
 * has_capability_noaudit - Does a task have a capability (unaudited) in the
 * initial user ns
 * @t: The task in question
 * @cap: The capability to be tested for
 *
 * Return true if the specified task has the given superior capability
 * currently in effect to init_user_ns, false if not.  Don't write an
 * audit message for the check.
 *
 * Note that this does not set PF_SUPERPRIV on the task.
 */
bool has_capability_noaudit(struct task_struct *t, int cap)
{
	return has_ns_capability_noaudit(t, &init_user_ns, cap);
}

/**
 * ns_capable - Determine if the current task has a superior capability in effect
 * @ns:  The usernamespace we want the capability in
 * @cap: The capability to be tested for
 *
 * Return true if the current task has the given superior capability currently
 * available for use, false if not.
 *
 * This sets PF_SUPERPRIV on the task if the capability is available on the
 * assumption that it's about to be used.
 */
bool ns_capable(struct user_namespace *ns, int cap)
{
	if (unlikely(!cap_valid(cap))) {
		printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
		BUG();
	}

	if (security_capable(current_cred(), ns, cap) == 0) {
		current->flags |= PF_SUPERPRIV;
		return true;
	}
	return false;
}
EXPORT_SYMBOL(ns_capable);

/**
 * capable - Determine if the current task has a superior capability in effect
 * @cap: The capability to be tested for
 *
 * Return true if the current task has the given superior capability currently
 * available for use, false if not.
 *
 * This sets PF_SUPERPRIV on the task if the capability is available on the
 * assumption that it's about to be used.
 */
bool capable(int cap)
{
	return ns_capable(&init_user_ns, cap);
}
EXPORT_SYMBOL(capable);

/**
 * nsown_capable - Check superior capability to one's own user_ns
 * @cap: The capability in question
 *
 * Return true if the current task has the given superior capability
 * targeted at its own user namespace.
 */
bool nsown_capable(int cap)
{
	return ns_capable(current_user_ns(), cap);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/kernel/capability.c
	3	*
	4	* Copyright (C) 1997 Andrew Main <[email protected]>
	5	*
72c2d582	6	* Integrated into 2.1.97+, Andrew G. Morgan <[email protected]>
1da177e4	7	* 30 May 2002: Cleanup, Robert M. Love <[email protected]>
314f70fd	8	*/
1da177e4	9
e68b75a0	10	#include <linux/audit.h>
c59ede7b	11	#include <linux/capability.h>
1da177e4	12	#include <linux/mm.h>
9984de1a	13	#include <linux/export.h>
1da177e4 LT	14	#include <linux/security.h>
1da177e4 LT	15	#include <linux/syscalls.h>
b460cbc5	16	#include <linux/pid_namespace.h>
3486740a	17	#include <linux/user_namespace.h>
1da177e4	18	#include <asm/uaccess.h>
1da177e4	19
e338d263 AM	20	/*
	21	* Leveraged for setting/resetting capabilities
	22	*/
	23
	24	const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
e338d263 AM	25
e338d263 AM	26	EXPORT_SYMBOL(__cap_empty_set);
e338d263	27
1f29fae2 SH	28	int file_caps_enabled = 1;
	29
	30	static int __init file_caps_disable(char *str)
	31	{
	32	file_caps_enabled = 0;
	33	return 1;
	34	}
	35	__setup("no_file_caps", file_caps_disable);
1f29fae2	36
e338d263 AM	37	/*
	38	* More recent versions of libcap are available from:
	39	*
	40	* http://www.kernel.org/pub/linux/libs/security/linux-privs/
	41	*/
	42
	43	static void warn_legacy_capability_use(void)
	44	{
	45	static int warned;
	46	if (!warned) {
	47	char name[sizeof(current->comm)];
	48
	49	printk(KERN_INFO "warning: `%s' uses 32-bit capabilities"
	50	" (legacy support in use)\n",
	51	get_task_comm(name, current));
	52	warned = 1;
	53	}
	54	}
	55
ca05a99a AM	56	/*
	57	* Version 2 capabilities worked fine, but the linux/capability.h file
	58	* that accompanied their introduction encouraged their use without
	59	* the necessary user-space source code changes. As such, we have
	60	* created a version 3 with equivalent functionality to version 2, but
	61	* with a header change to protect legacy source code from using
	62	* version 2 when it wanted to use version 1. If your system has code
	63	* that trips the following warning, it is using version 2 specific
	64	* capabilities and may be doing so insecurely.
	65	*
	66	* The remedy is to either upgrade your version of libcap (to 2.10+,
	67	* if the application is linked against it), or recompile your
	68	* application with modern kernel headers and this warning will go
	69	* away.
	70	*/
	71
	72	static void warn_deprecated_v2(void)
	73	{
	74	static int warned;
	75
	76	if (!warned) {
	77	char name[sizeof(current->comm)];
	78
	79	printk(KERN_INFO "warning: `%s' uses deprecated v2"
	80	" capabilities in a way that may be insecure.\n",
	81	get_task_comm(name, current));
	82	warned = 1;
	83	}
	84	}
	85
	86	/*
	87	* Version check. Return the number of u32s in each capability flag
	88	* array, or a negative value on error.
	89	*/
	90	static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
	91	{
	92	__u32 version;
	93
	94	if (get_user(version, &header->version))
	95	return -EFAULT;
	96
	97	switch (version) {
	98	case _LINUX_CAPABILITY_VERSION_1:
	99	warn_legacy_capability_use();
	100	*tocopy = _LINUX_CAPABILITY_U32S_1;
	101	break;
	102	case _LINUX_CAPABILITY_VERSION_2:
	103	warn_deprecated_v2();
	104	/*
	105	* fall through - v3 is otherwise equivalent to v2.
	106	*/
	107	case _LINUX_CAPABILITY_VERSION_3:
	108	*tocopy = _LINUX_CAPABILITY_U32S_3;
	109	break;
	110	default:
	111	if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
	112	return -EFAULT;
	113	return -EINVAL;
	114	}
	115
	116	return 0;
	117	}
	118
ab763c71	119	/*
d84f4f99 DH	120	* The only thing that can change the capabilities of the current
	121	* process is the current process. As such, we can't be in this code
	122	* at the same time as we are in the process of setting capabilities
	123	* in this process. The net result is that we can limit our use of
	124	* locks to when we are reading the caps of another process.
ab763c71 AM	125	*/
	126	static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
	127	kernel_cap_t pIp, kernel_cap_t pPp)
	128	{
	129	int ret;
	130
	131	if (pid && (pid != task_pid_vnr(current))) {
	132	struct task_struct *target;
	133
86fc80f1	134	rcu_read_lock();
ab763c71 AM	135
	136	target = find_task_by_vpid(pid);
	137	if (!target)
	138	ret = -ESRCH;
	139	else
	140	ret = security_capget(target, pEp, pIp, pPp);
	141
86fc80f1	142	rcu_read_unlock();
ab763c71 AM	143	} else
	144	ret = security_capget(current, pEp, pIp, pPp);
	145
	146	return ret;
	147	}
	148
207a7ba8	149	/**
1da177e4	150	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	151	* @header: pointer to struct that contains capability version and
	152	* target pid data
	153	* @dataptr: pointer to struct that contains the effective, permitted,
	154	* and inheritable capabilities that are returned
	155	*
	156	* Returns 0 on success and < 0 on error.
1da177e4	157	*/
b290ebe2	158	SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
1da177e4	159	{
314f70fd DW	160	int ret = 0;
314f70fd DW	161	pid_t pid;
e338d263 AM	162	unsigned tocopy;
e338d263 AM	163	kernel_cap_t pE, pI, pP;
314f70fd	164
ca05a99a	165	ret = cap_validate_magic(header, &tocopy);
c4a5af54 AM	166	if ((dataptr == NULL) \|\| (ret != 0))
c4a5af54 AM	167	return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
1da177e4	168
314f70fd DW	169	if (get_user(pid, &header->pid))
314f70fd DW	170	return -EFAULT;
1da177e4	171
314f70fd DW	172	if (pid < 0)
314f70fd DW	173	return -EINVAL;
1da177e4	174
ab763c71	175	ret = cap_get_target_pid(pid, &pE, &pI, &pP);
e338d263	176	if (!ret) {
ca05a99a	177	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
e338d263 AM	178	unsigned i;
	179
	180	for (i = 0; i < tocopy; i++) {
	181	kdata[i].effective = pE.cap[i];
	182	kdata[i].permitted = pP.cap[i];
	183	kdata[i].inheritable = pI.cap[i];
	184	}
	185
	186	/*
ca05a99a	187	* Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
e338d263 AM	188	* we silently drop the upper capabilities here. This
	189	* has the effect of making older libcap
	190	* implementations implicitly drop upper capability
	191	* bits when they perform a: capget/modify/capset
	192	* sequence.
	193	*
	194	* This behavior is considered fail-safe
	195	* behavior. Upgrading the application to a newer
	196	* version of libcap will enable access to the newer
	197	* capabilities.
	198	*
	199	* An alternative would be to return an error here
	200	* (-ERANGE), but that causes legacy applications to
	201	* unexpectidly fail; the capget/modify/capset aborts
	202	* before modification is attempted and the application
	203	* fails.
	204	*/
e338d263 AM	205	if (copy_to_user(dataptr, kdata, tocopy
	206	* sizeof(struct __user_cap_data_struct))) {
	207	return -EFAULT;
	208	}
	209	}
1da177e4	210
314f70fd	211	return ret;
1da177e4 LT	212	}
1da177e4 LT	213
207a7ba8	214	/**
ab763c71	215	* sys_capset - set capabilities for a process or (*) a group of processes
207a7ba8 RD	216	* @header: pointer to struct that contains capability version and
	217	* target pid data
	218	* @data: pointer to struct that contains the effective, permitted,
	219	* and inheritable capabilities
	220	*
1cdcbec1 DH	221	* Set capabilities for the current process only. The ability to any other
1cdcbec1 DH	222	* process(es) has been deprecated and removed.
1da177e4 LT	223	*
	224	* The restrictions on setting capabilities are specified as:
	225	*
1cdcbec1 DH	226	* I: any raised capabilities must be a subset of the old permitted
	227	* P: any raised capabilities must be a subset of the old permitted
	228	* E: must be set to a subset of new permitted
207a7ba8 RD	229	*
207a7ba8 RD	230	* Returns 0 on success and < 0 on error.
1da177e4	231	*/
b290ebe2	232	SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
1da177e4	233	{
ca05a99a	234	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
825332e4	235	unsigned i, tocopy, copybytes;
314f70fd	236	kernel_cap_t inheritable, permitted, effective;
d84f4f99	237	struct cred *new;
314f70fd DW	238	int ret;
	239	pid_t pid;
	240
ca05a99a AM	241	ret = cap_validate_magic(header, &tocopy);
	242	if (ret != 0)
	243	return ret;
314f70fd DW	244
	245	if (get_user(pid, &header->pid))
	246	return -EFAULT;
	247
1cdcbec1 DH	248	/* may only affect current now */
	249	if (pid != 0 && pid != task_pid_vnr(current))
	250	return -EPERM;
	251
825332e4 AV	252	copybytes = tocopy * sizeof(struct __user_cap_data_struct);
	253	if (copybytes > sizeof(kdata))
	254	return -EFAULT;
	255
	256	if (copy_from_user(&kdata, data, copybytes))
314f70fd	257	return -EFAULT;
e338d263 AM	258
	259	for (i = 0; i < tocopy; i++) {
	260	effective.cap[i] = kdata[i].effective;
	261	permitted.cap[i] = kdata[i].permitted;
	262	inheritable.cap[i] = kdata[i].inheritable;
	263	}
ca05a99a	264	while (i < _KERNEL_CAPABILITY_U32S) {
e338d263 AM	265	effective.cap[i] = 0;
	266	permitted.cap[i] = 0;
	267	inheritable.cap[i] = 0;
	268	i++;
	269	}
314f70fd	270
d84f4f99 DH	271	new = prepare_creds();
	272	if (!new)
	273	return -ENOMEM;
	274
	275	ret = security_capset(new, current_cred(),
	276	&effective, &inheritable, &permitted);
	277	if (ret < 0)
	278	goto error;
	279
57f71a0a	280	audit_log_capset(pid, new, current_cred());
e68b75a0	281
d84f4f99 DH	282	return commit_creds(new);
	283
	284	error:
	285	abort_creds(new);
314f70fd	286	return ret;
1da177e4	287	}
12b5989b	288
3263245d	289	/**
25e75703	290	* has_ns_capability - Does a task have a capability in a specific user ns
3263245d	291	* @t: The task in question
25e75703	292	* @ns: target user namespace
3263245d SH	293	* @cap: The capability to be tested for
	294	*
	295	* Return true if the specified task has the given superior capability
25e75703	296	* currently in effect to the specified user namespace, false if not.
3263245d SH	297	*
	298	* Note that this does not set PF_SUPERPRIV on the task.
	299	*/
25e75703 EP	300	bool has_ns_capability(struct task_struct *t,
25e75703 EP	301	struct user_namespace *ns, int cap)
3263245d	302	{
2920a840 EP	303	int ret;
	304
	305	rcu_read_lock();
25e75703	306	ret = security_capable(__task_cred(t), ns, cap);
2920a840	307	rcu_read_unlock();
3263245d SH	308
	309	return (ret == 0);
	310	}
	311
	312	/**
25e75703	313	* has_capability - Does a task have a capability in init_user_ns
3263245d	314	* @t: The task in question
3263245d SH	315	* @cap: The capability to be tested for
	316	*
	317	* Return true if the specified task has the given superior capability
25e75703	318	* currently in effect to the initial user namespace, false if not.
3263245d SH	319	*
	320	* Note that this does not set PF_SUPERPRIV on the task.
	321	*/
25e75703	322	bool has_capability(struct task_struct *t, int cap)
3263245d	323	{
25e75703	324	return has_ns_capability(t, &init_user_ns, cap);
3263245d SH	325	}
	326
	327	/**
7b61d648 EP	328	* has_ns_capability_noaudit - Does a task have a capability (unaudited)
7b61d648 EP	329	* in a specific user ns.
3263245d	330	* @t: The task in question
7b61d648	331	* @ns: target user namespace
3263245d SH	332	* @cap: The capability to be tested for
	333	*
	334	* Return true if the specified task has the given superior capability
7b61d648 EP	335	* currently in effect to the specified user namespace, false if not.
7b61d648 EP	336	* Do not write an audit message for the check.
3263245d SH	337	*
	338	* Note that this does not set PF_SUPERPRIV on the task.
	339	*/
7b61d648 EP	340	bool has_ns_capability_noaudit(struct task_struct *t,
7b61d648 EP	341	struct user_namespace *ns, int cap)
3263245d	342	{
2920a840 EP	343	int ret;
	344
	345	rcu_read_lock();
7b61d648	346	ret = security_capable_noaudit(__task_cred(t), ns, cap);
2920a840	347	rcu_read_unlock();
3263245d SH	348
	349	return (ret == 0);
	350	}
	351
5cd9c58f	352	/**
7b61d648 EP	353	* has_capability_noaudit - Does a task have a capability (unaudited) in the
	354	* initial user ns
	355	* @t: The task in question
5cd9c58f DH	356	* @cap: The capability to be tested for
5cd9c58f DH	357	*
7b61d648 EP	358	* Return true if the specified task has the given superior capability
	359	* currently in effect to init_user_ns, false if not. Don't write an
	360	* audit message for the check.
5cd9c58f	361	*
7b61d648	362	* Note that this does not set PF_SUPERPRIV on the task.
5cd9c58f	363	*/
7b61d648	364	bool has_capability_noaudit(struct task_struct *t, int cap)
3486740a	365	{
7b61d648	366	return has_ns_capability_noaudit(t, &init_user_ns, cap);
3486740a	367	}
3486740a SH	368
	369	/**
	370	* ns_capable - Determine if the current task has a superior capability in effect
	371	* @ns: The usernamespace we want the capability in
	372	* @cap: The capability to be tested for
	373	*
	374	* Return true if the current task has the given superior capability currently
	375	* available for use, false if not.
	376	*
	377	* This sets PF_SUPERPRIV on the task if the capability is available on the
	378	* assumption that it's about to be used.
	379	*/
	380	bool ns_capable(struct user_namespace *ns, int cap)
12b5989b	381	{
637d32dc EP	382	if (unlikely(!cap_valid(cap))) {
	383	printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
	384	BUG();
	385	}
	386
951880e6	387	if (security_capable(current_cred(), ns, cap) == 0) {
5cd9c58f	388	current->flags \|= PF_SUPERPRIV;
3486740a	389	return true;
12b5989b	390	}
3486740a	391	return false;
12b5989b	392	}
3486740a SH	393	EXPORT_SYMBOL(ns_capable);
	394
	395	/**
105ddf49 EP	396	* capable - Determine if the current task has a superior capability in effect
	397	* @cap: The capability to be tested for
	398	*
	399	* Return true if the current task has the given superior capability currently
	400	* available for use, false if not.
3486740a	401	*
105ddf49 EP	402	* This sets PF_SUPERPRIV on the task if the capability is available on the
105ddf49 EP	403	* assumption that it's about to be used.
3486740a	404	*/
105ddf49	405	bool capable(int cap)
3486740a	406	{
105ddf49	407	return ns_capable(&init_user_ns, cap);
3486740a	408	}
105ddf49	409	EXPORT_SYMBOL(capable);
47a150ed SH	410
	411	/**
	412	* nsown_capable - Check superior capability to one's own user_ns
	413	* @cap: The capability in question
	414	*
	415	* Return true if the current task has the given superior capability
	416	* targeted at its own user namespace.
	417	*/
	418	bool nsown_capable(int cap)
	419	{
	420	return ns_capable(current_user_ns(), cap);
	421	}