stream/tcp: re-enable midstream-policy usage

We were always setting it to ignore, due to bug 5825.

The engine will now issue an initialization error if an invalid value
is passed in the configuration file for midstream exception policy.

'pass-packet' or 'drop-packet' are never valid, as the midstream policy
concerns the whole flow, not making sense for just a packet.

If midstream is enabled, only two actual config values are allowed:
'ignore' and 'pass-flow', both in IDS and in IPS mode. In default mode
('auto' or if no policy is defined), midstream-policy is set to
'ignore'. All other values will lead to initialization error.

In IDS mode, 'drop-flow' will also lead to initialization error.

Part of
Bug #5825

(cherry picked from commit 69d3750aaf29940c87797eb49ceef7c385e06f43)

diff --git a/src/stream-tcp.c b/src/stream-tcp.c
index d736edef2a094ec02370ab9a06d5b55a55954110..cad45ea7f0883b4f13c8ceba692e299ed340c6d9 100644 (file)
--- a/src/stream-tcp.c
+++ b/src/stream-tcp.c
@@ -478,15 +478,7 @@ void StreamTcpInitConfig(char quiet)
     stream_config.ssn_memcap_policy = ExceptionPolicyParse("stream.memcap-policy", true);
     stream_config.reassembly_memcap_policy =
             ExceptionPolicyParse("stream.reassembly.memcap-policy", true);
-    SCLogConfig("memcap-policy: %u/%u", stream_config.ssn_memcap_policy,
-            stream_config.reassembly_memcap_policy);
-    stream_config.midstream_policy = ExceptionPolicyParse("stream.midstream-policy", true);
-    if (stream_config.midstream && stream_config.midstream_policy != EXCEPTION_POLICY_NOT_SET) {
-        SCLogWarning(SC_WARN_COMPATIBILITY,
-                "stream.midstream_policy setting conflicting with stream.midstream enabled. "
-                "Ignoring stream.midstream_policy.");
-        stream_config.midstream_policy = EXCEPTION_POLICY_NOT_SET;
-    }
+    stream_config.midstream_policy = ExceptionPolicyMidstreamParse(stream_config.midstream);
 
     if (!quiet) {
         SCLogConfig("stream.\"inline\": %s",
@@ -962,8 +954,7 @@ static int StreamTcpPacketStateNone(ThreadVars *tv, Packet *p,
             return 0;
         }
         if (!(stream_config.midstream_policy == EXCEPTION_POLICY_NOT_SET ||
-                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_FLOW ||
-                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_PACKET)) {
+                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_FLOW)) {
             SCLogDebug("Midstream policy not permissive, so won't pick up a session");
             return 0;
         }
@@ -1133,8 +1124,7 @@ static int StreamTcpPacketStateNone(ThreadVars *tv, Packet *p,
             return 0;
         }
         if (!(stream_config.midstream_policy == EXCEPTION_POLICY_NOT_SET ||
-                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_FLOW ||
-                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_PACKET)) {
+                    stream_config.midstream_policy == EXCEPTION_POLICY_PASS_FLOW)) {
             SCLogDebug("Midstream policy not permissive, so won't pick up a session");
             return 0;
         }