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-rw-r--r--security/selinux/avc.c52
1 files changed, 38 insertions, 14 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 6989472..07620bc94 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -741,6 +741,41 @@ int avc_ss_reset(u32 seqno)
return rc;
}
+/*
+ * Slow-path helper function for avc_has_perm_noaudit,
+ * when the avc_node lookup fails. We get called with
+ * the RCU read lock held, and need to return with it
+ * still held, but drop if for the security compute.
+ *
+ * Don't inline this, since it's the slow-path and just
+ * results in a bigger stack frame.
+ */
+static noinline struct avc_node *avc_compute_av(u32 ssid, u32 tsid,
+ u16 tclass, struct av_decision *avd)
+{
+ rcu_read_unlock();
+ security_compute_av(ssid, tsid, tclass, avd);
+ rcu_read_lock();
+ return avc_insert(ssid, tsid, tclass, avd);
+}
+
+static noinline int avc_denied(u32 ssid, u32 tsid,
+ u16 tclass, u32 requested,
+ unsigned flags,
+ struct av_decision *avd)
+{
+ if (flags & AVC_STRICT)
+ return -EACCES;
+
+ if (selinux_enforcing && !(avd->flags & AVD_FLAGS_PERMISSIVE))
+ return -EACCES;
+
+ avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
+ tsid, tclass, avd->seqno);
+ return 0;
+}
+
+
/**
* avc_has_perm_noaudit - Check permissions but perform no auditing.
* @ssid: source security identifier
@@ -776,26 +811,15 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
node = avc_lookup(ssid, tsid, tclass);
if (unlikely(!node)) {
- rcu_read_unlock();
- security_compute_av(ssid, tsid, tclass, avd);
- rcu_read_lock();
- node = avc_insert(ssid, tsid, tclass, avd);
+ node = avc_compute_av(ssid, tsid, tclass, avd);
} else {
memcpy(avd, &node->ae.avd, sizeof(*avd));
avd = &node->ae.avd;
}
denied = requested & ~(avd->allowed);
-
- if (denied) {
- if (flags & AVC_STRICT)
- rc = -EACCES;
- else if (!selinux_enforcing || (avd->flags & AVD_FLAGS_PERMISSIVE))
- avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
- tsid, tclass, avd->seqno);
- else
- rc = -EACCES;
- }
+ if (unlikely(denied))
+ rc = avc_denied(ssid, tsid, tclass, requested, flags, avd);
rcu_read_unlock();
return rc;
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