SELinux: check seqno when updating an avc_node
The avc update node callbacks do not check the seqno of the caller with the
seqno of the node found. It is possible that a policy change could happen
(although almost impossibly unlikely) in which a permissive or
permissive_domain decision is not valid for the entry found. Simply pass
and check that the seqno of the caller and the seqno of the node found
match.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index eb41f43..0d00f48 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -742,13 +742,15 @@
* @event : Updating event
* @perms : Permission mask bits
* @ssid,@tsid,@tclass : identifier of an AVC entry
+ * @seqno : sequence number when decision was made
*
* if a valid AVC entry doesn't exist,this function returns -ENOENT.
* if kmalloc() called internal returns NULL, this function returns -ENOMEM.
* otherwise, this function update the AVC entry. The original AVC-entry object
* will release later by RCU.
*/
-static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
+static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass,
+ u32 seqno)
{
int hvalue, rc = 0;
unsigned long flag;
@@ -767,7 +769,8 @@
list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
if (ssid == pos->ae.ssid &&
tsid == pos->ae.tsid &&
- tclass == pos->ae.tclass){
+ tclass == pos->ae.tclass &&
+ seqno == pos->ae.avd.seqno){
orig = pos;
break;
}
@@ -908,7 +911,7 @@
rc = -EACCES;
else if (!selinux_enforcing || security_permissive_sid(ssid))
avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
- tsid, tclass);
+ tsid, tclass, p_ae->avd.seqno);
else
rc = -EACCES;
}