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Commit 21193dcd authored by Eric Paris's avatar Eric Paris Committed by James Morris
Browse files

SELinux: more careful use of avd in avc_has_perm_noaudit 



we are often needlessly jumping through hoops when it comes to avd
entries in avc_has_perm_noaudit and we have extra initialization and memcpy
which are just wasting performance.  Try to clean the function up a bit.

This patch resulted in a 13% drop in time spent in avc_has_perm_noaudit in my
oprofile sampling of a tbench benchmark.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Reviewed-by: default avatarPaul Moore <paul.moore@hp.com>
Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 906d27d9

security/selinux/avc.c

+24 −19
Original line number Diff line number Diff line
@@ -350,12 +350,12 @@ out: 
	return node;

}



static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)

static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)

{

	node->ae.ssid = ssid;

	node->ae.tsid = tsid;

	node->ae.tclass = tclass;

	memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));

	memcpy(&node->ae.avd, avd, sizeof(node->ae.avd));

}



static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
@@ -435,31 +435,31 @@ static int avc_latest_notif_update(int seqno, int is_insert) 
 * @ssid: source security identifier

 * @tsid: target security identifier

 * @tclass: target security class

 * @ae: AVC entry

 * @avd: resulting av decision

 *

 * Insert an AVC entry for the SID pair

 * (@ssid, @tsid) and class @tclass.

 * The access vectors and the sequence number are

 * normally provided by the security server in

 * response to a security_compute_av() call.  If the

 * sequence number @ae->avd.seqno is not less than the latest

 * sequence number @avd->seqno is not less than the latest

 * revocation notification, then the function copies

 * the access vectors into a cache entry, returns

 * avc_node inserted. Otherwise, this function returns NULL.

 */

static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)

static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)

{

	struct avc_node *pos, *node = NULL;

	int hvalue;

	unsigned long flag;



	if (avc_latest_notif_update(ae->avd.seqno, 1))

	if (avc_latest_notif_update(avd->seqno, 1))

		goto out;



	node = avc_alloc_node();

	if (node) {

		hvalue = avc_hash(ssid, tsid, tclass);

		avc_node_populate(node, ssid, tsid, tclass, ae);

		avc_node_populate(node, ssid, tsid, tclass, avd);



		spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);

		list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
@@ -772,7 +772,7 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, 
	 * Copy and replace original node.

	 */



	avc_node_populate(node, ssid, tsid, tclass, &orig->ae);

	avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd);



	switch (event) {

	case AVC_CALLBACK_GRANT:
@@ -864,10 +864,10 @@ int avc_ss_reset(u32 seqno) 
int avc_has_perm_noaudit(u32 ssid, u32 tsid,

			 u16 tclass, u32 requested,

			 unsigned flags,

			 struct av_decision *avd)

			 struct av_decision *in_avd)

{

	struct avc_node *node;

	struct avc_entry entry, *p_ae;

	struct av_decision avd_entry, *avd;

	int rc = 0;

	u32 denied;
@@ -878,26 +878,31 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid, 
	node = avc_lookup(ssid, tsid, tclass, requested);

	if (!node) {

		rcu_read_unlock();

		rc = security_compute_av(ssid, tsid, tclass, requested, &entry.avd);



		if (in_avd)

			avd = in_avd;

		else

			avd = &avd_entry;



		rc = security_compute_av(ssid, tsid, tclass, requested, avd);

		if (rc)

			goto out;

		rcu_read_lock();

		node = avc_insert(ssid, tsid, tclass, &entry);

		node = avc_insert(ssid, tsid, tclass, avd);

	} else {

		if (in_avd)

			memcpy(in_avd, &node->ae.avd, sizeof(*in_avd));

		avd = &node->ae.avd;

	}



	p_ae = node ? &node->ae : &entry;



	if (avd)

		memcpy(avd, &p_ae->avd, sizeof(*avd));



	denied = requested & ~(p_ae->avd.allowed);

	denied = requested & ~(avd->allowed);



	if (denied) {

		if (flags & AVC_STRICT)

			rc = -EACCES;

		else if (!selinux_enforcing || security_permissive_sid(ssid))

			avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,

					tsid, tclass, p_ae->avd.seqno);

					tsid, tclass, avd->seqno);

		else

			rc = -EACCES;

	}