[linux-2.6-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>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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);

#ifdef CONFIG_MULTIUSER
/*
 * 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)
{
	char name[sizeof(current->comm)];

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

/*
 * 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)
{
	char name[sizeof(current->comm)];

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

/*
 * 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
		 * unexpectedly 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++;
	}

	effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
	permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
	inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;

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

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

	audit_log_capset(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))) {
		pr_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);
#endif /* CONFIG_MULTIUSER */

/**
 * file_ns_capable - Determine if the file's opener had a capability in effect
 * @file:  The file we want to check
 * @ns:  The usernamespace we want the capability in
 * @cap: The capability to be tested for
 *
 * Return true if task that opened the file had a capability in effect
 * when the file was opened.
 *
 * This does not set PF_SUPERPRIV because the caller may not
 * actually be privileged.
 */
bool file_ns_capable(const struct file *file, struct user_namespace *ns,
		     int cap)
{
	if (WARN_ON_ONCE(!cap_valid(cap)))
		return false;

	if (security_capable(file->f_cred, ns, cap) == 0)
		return true;

	return false;
}
EXPORT_SYMBOL(file_ns_capable);

/**
 * capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
 * @inode: The inode in question
 * @cap: The capability in question
 *
 * Return true if the current task has the given capability targeted at
 * its own user namespace and that the given inode's uid and gid are
 * mapped into the current user namespace.
 */
bool capable_wrt_inode_uidgid(const struct inode *inode, int cap)
{
	struct user_namespace *ns = current_user_ns();

	return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) &&
		kgid_has_mapping(ns, inode->i_gid);
}
EXPORT_SYMBOL(capable_wrt_inode_uidgid);
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
f5645d35 JP	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
f5645d35 JP	11
e68b75a0	12	#include <linux/audit.h>
c59ede7b	13	#include <linux/capability.h>
1da177e4	14	#include <linux/mm.h>
9984de1a	15	#include <linux/export.h>
1da177e4 LT	16	#include <linux/security.h>
1da177e4 LT	17	#include <linux/syscalls.h>
b460cbc5	18	#include <linux/pid_namespace.h>
3486740a	19	#include <linux/user_namespace.h>
1da177e4	20	#include <asm/uaccess.h>
1da177e4	21
e338d263 AM	22	/*
	23	* Leveraged for setting/resetting capabilities
	24	*/
	25
	26	const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
e338d263	27	EXPORT_SYMBOL(__cap_empty_set);
e338d263	28
1f29fae2 SH	29	int file_caps_enabled = 1;
	30
	31	static int __init file_caps_disable(char *str)
	32	{
	33	file_caps_enabled = 0;
	34	return 1;
	35	}
	36	__setup("no_file_caps", file_caps_disable);
1f29fae2	37
2813893f	38	#ifdef CONFIG_MULTIUSER
e338d263 AM	39	/*
	40	* More recent versions of libcap are available from:
	41	*
	42	* http://www.kernel.org/pub/linux/libs/security/linux-privs/
	43	*/
	44
	45	static void warn_legacy_capability_use(void)
	46	{
f5645d35 JP	47	char name[sizeof(current->comm)];
	48
	49	pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
	50	get_task_comm(name, current));
e338d263 AM	51	}
e338d263 AM	52
ca05a99a AM	53	/*
	54	* Version 2 capabilities worked fine, but the linux/capability.h file
	55	* that accompanied their introduction encouraged their use without
	56	* the necessary user-space source code changes. As such, we have
	57	* created a version 3 with equivalent functionality to version 2, but
	58	* with a header change to protect legacy source code from using
	59	* version 2 when it wanted to use version 1. If your system has code
	60	* that trips the following warning, it is using version 2 specific
	61	* capabilities and may be doing so insecurely.
	62	*
	63	* The remedy is to either upgrade your version of libcap (to 2.10+,
	64	* if the application is linked against it), or recompile your
	65	* application with modern kernel headers and this warning will go
	66	* away.
	67	*/
	68
	69	static void warn_deprecated_v2(void)
	70	{
f5645d35	71	char name[sizeof(current->comm)];
ca05a99a	72
f5645d35 JP	73	pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
f5645d35 JP	74	get_task_comm(name, current));
ca05a99a AM	75	}
	76
	77	/*
	78	* Version check. Return the number of u32s in each capability flag
	79	* array, or a negative value on error.
	80	*/
	81	static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
	82	{
	83	__u32 version;
	84
	85	if (get_user(version, &header->version))
	86	return -EFAULT;
	87
	88	switch (version) {
	89	case _LINUX_CAPABILITY_VERSION_1:
	90	warn_legacy_capability_use();
	91	*tocopy = _LINUX_CAPABILITY_U32S_1;
	92	break;
	93	case _LINUX_CAPABILITY_VERSION_2:
	94	warn_deprecated_v2();
	95	/*
	96	* fall through - v3 is otherwise equivalent to v2.
	97	*/
	98	case _LINUX_CAPABILITY_VERSION_3:
	99	*tocopy = _LINUX_CAPABILITY_U32S_3;
	100	break;
	101	default:
	102	if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
	103	return -EFAULT;
	104	return -EINVAL;
	105	}
	106
	107	return 0;
	108	}
	109
ab763c71	110	/*
d84f4f99 DH	111	* The only thing that can change the capabilities of the current
	112	* process is the current process. As such, we can't be in this code
	113	* at the same time as we are in the process of setting capabilities
	114	* in this process. The net result is that we can limit our use of
	115	* locks to when we are reading the caps of another process.
ab763c71 AM	116	*/
	117	static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
	118	kernel_cap_t pIp, kernel_cap_t pPp)
	119	{
	120	int ret;
	121
	122	if (pid && (pid != task_pid_vnr(current))) {
	123	struct task_struct *target;
	124
86fc80f1	125	rcu_read_lock();
ab763c71 AM	126
	127	target = find_task_by_vpid(pid);
	128	if (!target)
	129	ret = -ESRCH;
	130	else
	131	ret = security_capget(target, pEp, pIp, pPp);
	132
86fc80f1	133	rcu_read_unlock();
ab763c71 AM	134	} else
	135	ret = security_capget(current, pEp, pIp, pPp);
	136
	137	return ret;
	138	}
	139
207a7ba8	140	/**
1da177e4	141	* sys_capget - get the capabilities of a given process.
207a7ba8 RD	142	* @header: pointer to struct that contains capability version and
	143	* target pid data
	144	* @dataptr: pointer to struct that contains the effective, permitted,
	145	* and inheritable capabilities that are returned
	146	*
	147	* Returns 0 on success and < 0 on error.
1da177e4	148	*/
b290ebe2	149	SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
1da177e4	150	{
314f70fd DW	151	int ret = 0;
314f70fd DW	152	pid_t pid;
e338d263 AM	153	unsigned tocopy;
e338d263 AM	154	kernel_cap_t pE, pI, pP;
314f70fd	155
ca05a99a	156	ret = cap_validate_magic(header, &tocopy);
c4a5af54 AM	157	if ((dataptr == NULL) \|\| (ret != 0))
c4a5af54 AM	158	return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
1da177e4	159
314f70fd DW	160	if (get_user(pid, &header->pid))
314f70fd DW	161	return -EFAULT;
1da177e4	162
314f70fd DW	163	if (pid < 0)
314f70fd DW	164	return -EINVAL;
1da177e4	165
ab763c71	166	ret = cap_get_target_pid(pid, &pE, &pI, &pP);
e338d263	167	if (!ret) {
ca05a99a	168	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
e338d263 AM	169	unsigned i;
	170
	171	for (i = 0; i < tocopy; i++) {
	172	kdata[i].effective = pE.cap[i];
	173	kdata[i].permitted = pP.cap[i];
	174	kdata[i].inheritable = pI.cap[i];
	175	}
	176
	177	/*
ca05a99a	178	* Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
e338d263 AM	179	* we silently drop the upper capabilities here. This
	180	* has the effect of making older libcap
	181	* implementations implicitly drop upper capability
	182	* bits when they perform a: capget/modify/capset
	183	* sequence.
	184	*
	185	* This behavior is considered fail-safe
	186	* behavior. Upgrading the application to a newer
	187	* version of libcap will enable access to the newer
	188	* capabilities.
	189	*
	190	* An alternative would be to return an error here
	191	* (-ERANGE), but that causes legacy applications to
a6c8c690	192	* unexpectedly fail; the capget/modify/capset aborts
e338d263 AM	193	* before modification is attempted and the application
	194	* fails.
	195	*/
e338d263 AM	196	if (copy_to_user(dataptr, kdata, tocopy
	197	* sizeof(struct __user_cap_data_struct))) {
	198	return -EFAULT;
	199	}
	200	}
1da177e4	201
314f70fd	202	return ret;
1da177e4 LT	203	}
1da177e4 LT	204
207a7ba8	205	/**
ab763c71	206	* sys_capset - set capabilities for a process or (*) a group of processes
207a7ba8 RD	207	* @header: pointer to struct that contains capability version and
	208	* target pid data
	209	* @data: pointer to struct that contains the effective, permitted,
	210	* and inheritable capabilities
	211	*
1cdcbec1 DH	212	* Set capabilities for the current process only. The ability to any other
1cdcbec1 DH	213	* process(es) has been deprecated and removed.
1da177e4 LT	214	*
	215	* The restrictions on setting capabilities are specified as:
	216	*
1cdcbec1 DH	217	* I: any raised capabilities must be a subset of the old permitted
	218	* P: any raised capabilities must be a subset of the old permitted
	219	* E: must be set to a subset of new permitted
207a7ba8 RD	220	*
207a7ba8 RD	221	* Returns 0 on success and < 0 on error.
1da177e4	222	*/
b290ebe2	223	SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
1da177e4	224	{
ca05a99a	225	struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
825332e4	226	unsigned i, tocopy, copybytes;
314f70fd	227	kernel_cap_t inheritable, permitted, effective;
d84f4f99	228	struct cred *new;
314f70fd DW	229	int ret;
	230	pid_t pid;
	231
ca05a99a AM	232	ret = cap_validate_magic(header, &tocopy);
	233	if (ret != 0)
	234	return ret;
314f70fd DW	235
	236	if (get_user(pid, &header->pid))
	237	return -EFAULT;
	238
1cdcbec1 DH	239	/* may only affect current now */
	240	if (pid != 0 && pid != task_pid_vnr(current))
	241	return -EPERM;
	242
825332e4 AV	243	copybytes = tocopy * sizeof(struct __user_cap_data_struct);
	244	if (copybytes > sizeof(kdata))
	245	return -EFAULT;
	246
	247	if (copy_from_user(&kdata, data, copybytes))
314f70fd	248	return -EFAULT;
e338d263 AM	249
	250	for (i = 0; i < tocopy; i++) {
	251	effective.cap[i] = kdata[i].effective;
	252	permitted.cap[i] = kdata[i].permitted;
	253	inheritable.cap[i] = kdata[i].inheritable;
	254	}
ca05a99a	255	while (i < _KERNEL_CAPABILITY_U32S) {
e338d263 AM	256	effective.cap[i] = 0;
	257	permitted.cap[i] = 0;
	258	inheritable.cap[i] = 0;
	259	i++;
	260	}
314f70fd	261
7d8b6c63 EP	262	effective.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
	263	permitted.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
	264	inheritable.cap[CAP_LAST_U32] &= CAP_LAST_U32_VALID_MASK;
	265
d84f4f99 DH	266	new = prepare_creds();
	267	if (!new)
	268	return -ENOMEM;
	269
	270	ret = security_capset(new, current_cred(),
	271	&effective, &inheritable, &permitted);
	272	if (ret < 0)
	273	goto error;
	274
ca24a23e	275	audit_log_capset(new, current_cred());
e68b75a0	276
d84f4f99 DH	277	return commit_creds(new);
	278
	279	error:
	280	abort_creds(new);
314f70fd	281	return ret;
1da177e4	282	}
12b5989b	283
3263245d	284	/**
25e75703	285	* has_ns_capability - Does a task have a capability in a specific user ns
3263245d	286	* @t: The task in question
25e75703	287	* @ns: target user namespace
3263245d SH	288	* @cap: The capability to be tested for
	289	*
	290	* Return true if the specified task has the given superior capability
25e75703	291	* currently in effect to the specified user namespace, false if not.
3263245d SH	292	*
	293	* Note that this does not set PF_SUPERPRIV on the task.
	294	*/
25e75703 EP	295	bool has_ns_capability(struct task_struct *t,
25e75703 EP	296	struct user_namespace *ns, int cap)
3263245d	297	{
2920a840 EP	298	int ret;
	299
	300	rcu_read_lock();
25e75703	301	ret = security_capable(__task_cred(t), ns, cap);
2920a840	302	rcu_read_unlock();
3263245d SH	303
	304	return (ret == 0);
	305	}
	306
	307	/**
25e75703	308	* has_capability - Does a task have a capability in init_user_ns
3263245d	309	* @t: The task in question
3263245d SH	310	* @cap: The capability to be tested for
	311	*
	312	* Return true if the specified task has the given superior capability
25e75703	313	* currently in effect to the initial user namespace, false if not.
3263245d SH	314	*
	315	* Note that this does not set PF_SUPERPRIV on the task.
	316	*/
25e75703	317	bool has_capability(struct task_struct *t, int cap)
3263245d	318	{
25e75703	319	return has_ns_capability(t, &init_user_ns, cap);
3263245d SH	320	}
	321
	322	/**
7b61d648 EP	323	* has_ns_capability_noaudit - Does a task have a capability (unaudited)
7b61d648 EP	324	* in a specific user ns.
3263245d	325	* @t: The task in question
7b61d648	326	* @ns: target user namespace
3263245d SH	327	* @cap: The capability to be tested for
	328	*
	329	* Return true if the specified task has the given superior capability
7b61d648 EP	330	* currently in effect to the specified user namespace, false if not.
7b61d648 EP	331	* Do not write an audit message for the check.
3263245d SH	332	*
	333	* Note that this does not set PF_SUPERPRIV on the task.
	334	*/
7b61d648 EP	335	bool has_ns_capability_noaudit(struct task_struct *t,
7b61d648 EP	336	struct user_namespace *ns, int cap)
3263245d	337	{
2920a840 EP	338	int ret;
	339
	340	rcu_read_lock();
7b61d648	341	ret = security_capable_noaudit(__task_cred(t), ns, cap);
2920a840	342	rcu_read_unlock();
3263245d SH	343
	344	return (ret == 0);
	345	}
	346
5cd9c58f	347	/**
7b61d648 EP	348	* has_capability_noaudit - Does a task have a capability (unaudited) in the
	349	* initial user ns
	350	* @t: The task in question
5cd9c58f DH	351	* @cap: The capability to be tested for
5cd9c58f DH	352	*
7b61d648 EP	353	* Return true if the specified task has the given superior capability
	354	* currently in effect to init_user_ns, false if not. Don't write an
	355	* audit message for the check.
5cd9c58f	356	*
7b61d648	357	* Note that this does not set PF_SUPERPRIV on the task.
5cd9c58f	358	*/
7b61d648	359	bool has_capability_noaudit(struct task_struct *t, int cap)
3486740a	360	{
7b61d648	361	return has_ns_capability_noaudit(t, &init_user_ns, cap);
3486740a	362	}
3486740a SH	363
	364	/**
	365	* ns_capable - Determine if the current task has a superior capability in effect
	366	* @ns: The usernamespace we want the capability in
	367	* @cap: The capability to be tested for
	368	*
	369	* Return true if the current task has the given superior capability currently
	370	* available for use, false if not.
	371	*
	372	* This sets PF_SUPERPRIV on the task if the capability is available on the
	373	* assumption that it's about to be used.
	374	*/
	375	bool ns_capable(struct user_namespace *ns, int cap)
12b5989b	376	{
637d32dc	377	if (unlikely(!cap_valid(cap))) {
f5645d35	378	pr_crit("capable() called with invalid cap=%u\n", cap);
637d32dc EP	379	BUG();
	380	}
	381
951880e6	382	if (security_capable(current_cred(), ns, cap) == 0) {
5cd9c58f	383	current->flags \|= PF_SUPERPRIV;
3486740a	384	return true;
12b5989b	385	}
3486740a	386	return false;
12b5989b	387	}
3486740a SH	388	EXPORT_SYMBOL(ns_capable);
3486740a SH	389
2813893f IM	390
	391	/**
	392	* capable - Determine if the current task has a superior capability in effect
	393	* @cap: The capability to be tested for
	394	*
	395	* Return true if the current task has the given superior capability currently
	396	* available for use, false if not.
	397	*
	398	* This sets PF_SUPERPRIV on the task if the capability is available on the
	399	* assumption that it's about to be used.
	400	*/
	401	bool capable(int cap)
	402	{
	403	return ns_capable(&init_user_ns, cap);
	404	}
	405	EXPORT_SYMBOL(capable);
	406	#endif /* CONFIG_MULTIUSER */
	407
935d8aab LT	408	/**
	409	* file_ns_capable - Determine if the file's opener had a capability in effect
	410	* @file: The file we want to check
	411	* @ns: The usernamespace we want the capability in
	412	* @cap: The capability to be tested for
	413	*
	414	* Return true if task that opened the file had a capability in effect
	415	* when the file was opened.
	416	*
	417	* This does not set PF_SUPERPRIV because the caller may not
	418	* actually be privileged.
	419	*/
a6c8c690 FF	420	bool file_ns_capable(const struct file file, struct user_namespace ns,
a6c8c690 FF	421	int cap)
935d8aab LT	422	{
	423	if (WARN_ON_ONCE(!cap_valid(cap)))
	424	return false;
	425
	426	if (security_capable(file->f_cred, ns, cap) == 0)
	427	return true;
	428
	429	return false;
	430	}
	431	EXPORT_SYMBOL(file_ns_capable);
	432
1a48e2ac	433	/**
23adbe12	434	* capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
1a48e2ac EB	435	* @inode: The inode in question
	436	* @cap: The capability in question
	437	*
23adbe12 AL	438	* Return true if the current task has the given capability targeted at
	439	* its own user namespace and that the given inode's uid and gid are
	440	* mapped into the current user namespace.
1a48e2ac	441	*/
23adbe12	442	bool capable_wrt_inode_uidgid(const struct inode *inode, int cap)
1a48e2ac EB	443	{
	444	struct user_namespace *ns = current_user_ns();
	445
23adbe12 AL	446	return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) &&
23adbe12 AL	447	kgid_has_mapping(ns, inode->i_gid);
1a48e2ac	448	}
23adbe12	449	EXPORT_SYMBOL(capable_wrt_inode_uidgid);