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Commit 9f2ad665 authored by Paul Moore's avatar Paul Moore Committed by David S. Miller
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NetLabel: SELinux cleanups 



This patch does a lot of cleanup in the SELinux NetLabel support code.  A
summary of the changes include:

* Use RCU locking for the NetLabel state variable in the skk_security_struct
  instead of using the inode_security_struct mutex.
* Remove unnecessary parameters in selinux_netlbl_socket_post_create().
* Rename selinux_netlbl_sk_clone_security() to
  selinux_netlbl_sk_security_clone() to better fit the other NetLabel
  sk_security functions.
* Improvements to selinux_netlbl_inode_permission() to help reduce the cost of
  the common case.

Signed-off-by: default avatarPaul Moore <paul.moore@hp.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 9bb5fd2b

security/selinux/hooks.c

+5 −5
Original line number Diff line number Diff line
@@ -3140,9 +3140,7 @@ static int selinux_socket_post_create(struct socket *sock, int family, 
	if (sock->sk) {

		sksec = sock->sk->sk_security;

		sksec->sid = isec->sid;

		err = selinux_netlbl_socket_post_create(sock,

							family,

							isec->sid);

		err = selinux_netlbl_socket_post_create(sock);

	}



	return err;
@@ -3661,7 +3659,7 @@ static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk) 
	newssec->sid = ssec->sid;

	newssec->peer_sid = ssec->peer_sid;



	selinux_netlbl_sk_clone_security(ssec, newssec);

	selinux_netlbl_sk_security_clone(ssec, newssec);

}



static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
@@ -3730,7 +3728,9 @@ static void selinux_inet_csk_clone(struct sock *newsk, 
	   So we will wait until sock_graft to do it, by which

	   time it will have been created and available. */



	selinux_netlbl_sk_security_init(newsksec, req->rsk_ops->family);

	/* We don't need to take any sort of lock here as we are the only

	 * thread with access to newsksec */

	selinux_netlbl_sk_security_reset(newsksec, req->rsk_ops->family);

}



static void selinux_inet_conn_established(struct sock *sk,

security/selinux/include/objsec.h

+2 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/fs.h>

#include <linux/binfmts.h>

#include <linux/in.h>

#include <linux/spinlock.h>

#include "flask.h"

#include "avc.h"
@@ -108,6 +109,7 @@ struct sk_security_struct { 
		NLBL_REQUIRE,

		NLBL_LABELED,

	} nlbl_state;

	spinlock_t nlbl_lock;		/* protects nlbl_state */

#endif

};

security/selinux/include/selinux_netlabel.h

+13 −8
Original line number Diff line number Diff line
@@ -38,9 +38,7 @@ 


#ifdef CONFIG_NETLABEL

void selinux_netlbl_cache_invalidate(void);

int selinux_netlbl_socket_post_create(struct socket *sock,

				      int sock_family,

				      u32 sid);

int selinux_netlbl_socket_post_create(struct socket *sock);

void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock);

u32 selinux_netlbl_inet_conn_request(struct sk_buff *skb, u32 sock_sid);

int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
@@ -48,9 +46,11 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, 
				struct avc_audit_data *ad);

u32 selinux_netlbl_socket_getpeersec_stream(struct socket *sock);

u32 selinux_netlbl_socket_getpeersec_dgram(struct sk_buff *skb);

void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,

				      int family);

void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec,

				     int family);

void selinux_netlbl_sk_clone_security(struct sk_security_struct *ssec,

void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec,

				      struct sk_security_struct *newssec);

int selinux_netlbl_inode_permission(struct inode *inode, int mask);

int selinux_netlbl_socket_setsockopt(struct socket *sock,
@@ -62,9 +62,7 @@ static inline void selinux_netlbl_cache_invalidate(void) 
	return;

}



static inline int selinux_netlbl_socket_post_create(struct socket *sock,

						    int sock_family,

						    u32 sid)

static inline int selinux_netlbl_socket_post_create(struct socket *sock)

{

	return 0;

}
@@ -98,6 +96,13 @@ static inline u32 selinux_netlbl_socket_getpeersec_dgram(struct sk_buff *skb) 
	return SECSID_NULL;

}



static inline void selinux_netlbl_sk_security_reset(

					       struct sk_security_struct *ssec,

					       int family)

{

	return;

}



static inline void selinux_netlbl_sk_security_init(

	                                       struct sk_security_struct *ssec,

					       int family)
@@ -105,7 +110,7 @@ static inline void selinux_netlbl_sk_security_init( 
	return;

}



static inline void selinux_netlbl_sk_clone_security(

static inline void selinux_netlbl_sk_security_clone(

	                                   struct sk_security_struct *ssec,

					   struct sk_security_struct *newssec)

{

security/selinux/ss/services.c

+66 −41
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <linux/slab.h>

#include <linux/string.h>

#include <linux/spinlock.h>

#include <linux/rcupdate.h>

#include <linux/errno.h>

#include <linux/in.h>

#include <linux/sched.h>
@@ -2435,7 +2436,9 @@ static int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, 
 *

 * Description:

 * Attempt to label a socket using the NetLabel mechanism using the given

 * SID.  Returns zero values on success, negative values on failure.

 * SID.  Returns zero values on success, negative values on failure.  The

 * caller is responsibile for calling rcu_read_lock() before calling this

 * this function and rcu_read_unlock() after this function returns.

 *

 */

static int selinux_netlbl_socket_setsid(struct socket *sock, u32 sid)
@@ -2472,8 +2475,11 @@ static int selinux_netlbl_socket_setsid(struct socket *sock, u32 sid) 
		secattr.flags |= NETLBL_SECATTR_MLS_CAT;



	rc = netlbl_socket_setattr(sock, &secattr);

	if (rc == 0)

	if (rc == 0) {

		spin_lock(&sksec->nlbl_lock);

		sksec->nlbl_state = NLBL_LABELED;

		spin_unlock(&sksec->nlbl_lock);

	}



netlbl_socket_setsid_return:

	POLICY_RDUNLOCK;
@@ -2482,16 +2488,16 @@ static int selinux_netlbl_socket_setsid(struct socket *sock, u32 sid) 
}



/**

 * selinux_netlbl_sk_security_init - Setup the NetLabel fields

 * selinux_netlbl_sk_security_reset - Reset the NetLabel fields

 * @ssec: the sk_security_struct

 * @family: the socket family

 *

 * Description:

 * Called when a new sk_security_struct is allocated to initialize the NetLabel

 * fields.

 * Called when the NetLabel state of a sk_security_struct needs to be reset.

 * The caller is responsibile for all the NetLabel sk_security_struct locking.

 *

 */

void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec,

void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,

				      int family)

{

        if (family == PF_INET)
@@ -2501,7 +2507,25 @@ void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec, 
}



/**

 * selinux_netlbl_sk_clone_security - Copy the NetLabel fields

 * selinux_netlbl_sk_security_init - Setup the NetLabel fields

 * @ssec: the sk_security_struct

 * @family: the socket family

 *

 * Description:

 * Called when a new sk_security_struct is allocated to initialize the NetLabel

 * fields.

 *

 */

void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec,

				     int family)

{

	/* No locking needed, we are the only one who has access to ssec */

	selinux_netlbl_sk_security_reset(ssec, family);

	spin_lock_init(&ssec->nlbl_lock);

}



/**

 * selinux_netlbl_sk_security_clone - Copy the NetLabel fields

 * @ssec: the original sk_security_struct

 * @newssec: the cloned sk_security_struct

 *
@@ -2510,41 +2534,41 @@ void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec, 
 * @newssec.

 *

 */

void selinux_netlbl_sk_clone_security(struct sk_security_struct *ssec,

void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec,

				      struct sk_security_struct *newssec)

{

	/* We don't need to take newssec->nlbl_lock because we are the only

	 * thread with access to newssec, but we do need to take the RCU read

	 * lock as other threads could have access to ssec */

	rcu_read_lock();

	selinux_netlbl_sk_security_reset(newssec, ssec->sk->sk_family);

	newssec->sclass = ssec->sclass;

	if (ssec->nlbl_state != NLBL_UNSET)

		newssec->nlbl_state = NLBL_REQUIRE;

	else

		newssec->nlbl_state = NLBL_UNSET;

	rcu_read_unlock();

}



/**

 * selinux_netlbl_socket_post_create - Label a socket using NetLabel

 * @sock: the socket to label

 * @sock_family: the socket family

 * @sid: the SID to use

 *

 * Description:

 * Attempt to label a socket using the NetLabel mechanism using the given

 * SID.  Returns zero values on success, negative values on failure.

 *

 */

int selinux_netlbl_socket_post_create(struct socket *sock,

				      int sock_family,

				      u32 sid)

int selinux_netlbl_socket_post_create(struct socket *sock)

{

	int rc = 0;

	struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;

	struct sk_security_struct *sksec = sock->sk->sk_security;



	sksec->sclass = isec->sclass;



	if (sock_family != PF_INET)

		return 0;

	rcu_read_lock();

	if (sksec->nlbl_state == NLBL_REQUIRE)

		rc = selinux_netlbl_socket_setsid(sock, sksec->sid);

	rcu_read_unlock();



	sksec->nlbl_state = NLBL_REQUIRE;

	return selinux_netlbl_socket_setsid(sock, sid);

	return rc;

}



/**
@@ -2566,8 +2590,12 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) 


	sksec->sclass = isec->sclass;



	if (sk->sk_family != PF_INET)

	rcu_read_lock();



	if (sksec->nlbl_state != NLBL_REQUIRE) {

		rcu_read_unlock();

		return;

	}



	netlbl_secattr_init(&secattr);

	if (netlbl_sock_getattr(sk, &secattr) == 0 &&
@@ -2579,12 +2607,12 @@ void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) 
		sksec->peer_sid = nlbl_peer_sid;

	netlbl_secattr_destroy(&secattr);



	sksec->nlbl_state = NLBL_REQUIRE;



	/* Try to set the NetLabel on the socket to save time later, if we fail

	 * here we will pick up the pieces in later calls to

	 * selinux_netlbl_inode_permission(). */

	selinux_netlbl_socket_setsid(sock, sksec->sid);



	rcu_read_unlock();

}



/**
@@ -2625,25 +2653,24 @@ u32 selinux_netlbl_inet_conn_request(struct sk_buff *skb, u32 sock_sid) 
int selinux_netlbl_inode_permission(struct inode *inode, int mask)

{

	int rc;

	struct inode_security_struct *isec;

	struct sk_security_struct *sksec;

	struct socket *sock;



	if (!S_ISSOCK(inode->i_mode))

	if (!S_ISSOCK(inode->i_mode) ||

	    ((mask & (MAY_WRITE | MAY_APPEND)) == 0))

		return 0;



	sock = SOCKET_I(inode);

	isec = inode->i_security;

	sksec = sock->sk->sk_security;

	mutex_lock(&isec->lock);

	if (unlikely(sksec->nlbl_state == NLBL_REQUIRE &&

		     (mask & (MAY_WRITE | MAY_APPEND)))) {



	rcu_read_lock();

	if (sksec->nlbl_state != NLBL_REQUIRE) {

		rcu_read_unlock();

		return 0;

	}

	lock_sock(sock->sk);

	rc = selinux_netlbl_socket_setsid(sock, sksec->sid);

	release_sock(sock->sk);

	} else

		rc = 0;

	mutex_unlock(&isec->lock);

	rcu_read_unlock();



	return rc;

}
@@ -2754,12 +2781,10 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, 
				     int optname)

{

	int rc = 0;

	struct inode *inode = SOCK_INODE(sock);

	struct sk_security_struct *sksec = sock->sk->sk_security;

	struct inode_security_struct *isec = inode->i_security;

	struct netlbl_lsm_secattr secattr;



	mutex_lock(&isec->lock);

	rcu_read_lock();

	if (level == IPPROTO_IP && optname == IP_OPTIONS &&

	    sksec->nlbl_state == NLBL_LABELED) {

		netlbl_secattr_init(&secattr);
@@ -2768,7 +2793,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, 
			rc = -EACCES;

		netlbl_secattr_destroy(&secattr);

	}

	mutex_unlock(&isec->lock);

	rcu_read_unlock();



	return rc;

}