stream: special handling for RST data

Data on RST packets is not invalid, but also shouldn't be used
in reassembly.

RFC 1122:

  4.2.2.12  RST Segment: RFC-793 Section 3.4

    A TCP SHOULD allow a received RST segment to include data.

    DISCUSSION
        It has been suggested that a RST segment could contain
        ASCII text that encoded and explained the cause of the
        RST.  No standard has yet been established for such
        data.

RST data will be presented to the detection engine per packet,
but will not be part of stream reassembly.

Bug: #6244.

diff --git a/src/stream-tcp-reassemble.c b/src/stream-tcp-reassemble.c
index 90bac3c649497b0d60094259f7e92f83f841c89a..135b22485c0476f0f004f5331c8aefbc62587260 100644 (file)
--- a/src/stream-tcp-reassemble.c
+++ b/src/stream-tcp-reassemble.c
@@ -2009,7 +2009,8 @@ int StreamTcpReassembleHandleSegment(ThreadVars *tv, TcpReassemblyThreadCtx *ra_
         }
     }
     /* if this segment contains data, insert it */
-    if (p->payload_len > 0 && !(stream->flags & STREAMTCP_STREAM_FLAG_NOREASSEMBLY)) {
+    if (p->payload_len > 0 && !(stream->flags & STREAMTCP_STREAM_FLAG_NOREASSEMBLY) &&
+            (p->tcph->th_flags & TH_RST) == 0) {
         SCLogDebug("calling StreamTcpReassembleHandleSegmentHandleData");
 
         if (StreamTcpReassembleHandleSegmentHandleData(tv, ra_ctx, ssn, stream, p) != 0) {
@@ -2024,10 +2025,9 @@ int StreamTcpReassembleHandleSegment(ThreadVars *tv, TcpReassemblyThreadCtx *ra_
         p->flags |= PKT_STREAM_ADD;
     } else {
         SCLogDebug("ssn %p / stream %p: not calling StreamTcpReassembleHandleSegmentHandleData:"
-                " p->payload_len %u, STREAMTCP_STREAM_FLAG_NOREASSEMBLY %s",
+                   " p->payload_len %u, STREAMTCP_STREAM_FLAG_NOREASSEMBLY %s",
                 ssn, stream, p->payload_len,
                 (stream->flags & STREAMTCP_STREAM_FLAG_NOREASSEMBLY) ? "true" : "false");
-
     }
 
     /* if the STREAMTCP_STREAM_FLAG_DEPTH_REACHED is set, but not the