From a5dda683328f99c781f92c66cc52ffc0639bef58 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 12 Feb 2009 14:50:11 -0500 Subject: [PATCH] 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 Acked-by: Stephen Smalley Signed-off-by: James Morris --- security/selinux/avc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/security/selinux/avc.c b/security/selinux/avc.c index eb41f43e277..0d00f4874f3 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -742,13 +742,15 @@ static inline int avc_sidcmp(u32 x, u32 y) * @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 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass) 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 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid, 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; }