From Didier via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=3055 :

Apply rev 25869 to most of the rest of the TCP-desegmenting dissectors.
(The SSL dissector was already updated in one of two spots with bug 4535/rev
32456.)

A couple of the patches had to be manually applied.

From me: Fix the comments to match the change (including in the TCP and SSL
dissectors.)

svn path=/trunk/; revision=36332

10 files changed, 113 insertions, 49 deletions

diff --git a/asn1/snmp/packet-snmp-template.c b/asn1/snmp/packet-snmp-template.c
index be94c9b073..03839f7660 100644
--- a/asn1/snmp/packet-snmp-template.c
+++ b/asn1/snmp/packet-snmp-template.c
@@ -1561,8 +1561,16 @@ dissect_snmp_pdu(tvbuff_t *tvb, int offset, packet_info *pinfo,
 		 * BER).
 		 */
 		if (length_remaining < 6) {
+			/*
+			 * Yes.  Tell the TCP dissector where the data
+			 * for this message starts in the data it handed
+			 * us and that we need "some more data."  Don't tell
+			 * it exactly how many bytes we need because if/when
+			 * we ask for even more (after the header) that will
+			 * break reassembly.
+			 */
 			pinfo->desegment_offset = offset;
-			pinfo->desegment_len = 6 - length_remaining;
+			pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 
 			/*
 			 * Return 0, which means "I didn't dissect anything
diff --git a/epan/dissectors/packet-bgp.c b/epan/dissectors/packet-bgp.c
index 3dafdd8bd3..edc5fd85dd 100644
--- a/epan/dissectors/packet-bgp.c
+++ b/epan/dissectors/packet-bgp.c
@@ -2912,12 +2912,14 @@ dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	     */
 	    if (length_remaining < BGP_HEADER_SIZE) {
 		/*
-		 * Yes.  Tell the TCP dissector where the data for this
-		 * message starts in the data it handed us, and how many
-		 * more bytes we need, and return.
+		 * Yes.  Tell the TCP dissector where the data for this message
+		 * starts in the data it handed us and that we need "some more
+		 * data."  Don't tell it exactly how many bytes we need because
+		 * if/when we ask for even more (after the header) that will
+		 * break reassembly.
 		 */
 		pinfo->desegment_offset = offset;
-		pinfo->desegment_len = BGP_HEADER_SIZE - length_remaining;
+		pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 		return;
 	    }
 	}
diff --git a/epan/dissectors/packet-rtsp.c b/epan/dissectors/packet-rtsp.c
index 8463c7b16f..f5c5ca9e1e 100644
--- a/epan/dissectors/packet-rtsp.c
+++ b/epan/dissectors/packet-rtsp.c
@@ -156,12 +156,15 @@ dissect_rtspinterleaved(tvbuff_t *tvb, int offset, packet_info *pinfo,
 		 */
 		if (length_remaining < 4) {
 			/*
-			 * Yes.  Tell the TCP dissector where the data
-			 * for this message starts in the data it handed
-			 * us, and how many more bytes we need, and return.
+			 * Yes.  Tell the TCP dissector where the data for
+			 * this message starts in the data it handed us and
+			 * that we need "some more data."  Don't tell it
+			 * exactly how many bytes we need because if/when we
+			 * ask for even more (after the header) that will
+			 * break reassembly.
 			 */
 			pinfo->desegment_offset = offset;
-			pinfo->desegment_len = 4 - length_remaining;
+			pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 			return -1;
 		}
 	}
diff --git a/epan/dissectors/packet-snmp.c b/epan/dissectors/packet-snmp.c
index e5a650ea3b..3c14c631a9 100644
--- a/epan/dissectors/packet-snmp.c
+++ b/epan/dissectors/packet-snmp.c
@@ -1,7 +1,7 @@
 /* Do not modify this file.                                                   */
 /* It is created automatically by the ASN.1 to Wireshark dissector compiler   */
 /* packet-snmp.c                                                              */
-/* ../../tools/asn2wrs.py -b -p snmp -c ./snmp.cnf -s ./packet-snmp-template -D . snmp.asn */
+/* ../../../tools/asn2wrs.py -b -p snmp -c ../../../asn1/snmp/snmp.cnf -s ../../../asn1/snmp/packet-snmp-template -D ../../../asn1/snmp snmp.asn */
 
 /* Input file: packet-snmp-template.c */
 
@@ -2785,8 +2785,16 @@ dissect_snmp_pdu(tvbuff_t *tvb, int offset, packet_info *pinfo,
 		 * BER).
 		 */
 		if (length_remaining < 6) {
+			/*
+			 * Yes.  Tell the TCP dissector where the data
+			 * for this message starts in the data it handed
+			 * us and that we need "some more data."  Don't tell
+			 * it exactly how many bytes we need because if/when
+			 * we ask for even more (after the header) that will
+			 * break reassembly.
+			 */
 			pinfo->desegment_offset = offset;
-			pinfo->desegment_len = 6 - length_remaining;
+			pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 
 			/*
 			 * Return 0, which means "I didn't dissect anything
@@ -3625,7 +3633,7 @@ void proto_register_snmp(void) {
         NULL, HFILL }},
 
 /*--- End of included file: packet-snmp-hfarr.c ---*/
-#line 2140 "packet-snmp-template.c"
+#line 2148 "packet-snmp-template.c"
   };
 
   /* List of subtrees */
@@ -3665,7 +3673,7 @@ void proto_register_snmp(void) {
     &ett_snmp_RReqPDU_U,
 
 /*--- End of included file: packet-snmp-ettarr.c ---*/
-#line 2156 "packet-snmp-template.c"
+#line 2164 "packet-snmp-template.c"
   };
   module_t *snmp_module;
 
diff --git a/epan/dissectors/packet-ssh.c b/epan/dissectors/packet-ssh.c
index b1a2053abd..93d7701a32 100644
--- a/epan/dissectors/packet-ssh.c
+++ b/epan/dissectors/packet-ssh.c
@@ -497,10 +497,25 @@ ssh_dissect_ssh1(tvbuff_t *tvb, packet_info *pinfo,
 	 * This means we're guaranteed that "remain_length" is positive.
 	 */
 	remain_length = tvb_ensure_length_remaining(tvb,offset);
+	/*
+	 * Can we do reassembly?
+	 */
 	if (ssh_desegment && pinfo->can_desegment) {
+		/*
+		 * Yes - would an SSH header starting at this offset be split
+		 * across segment boundaries?
+		 */
 		if(remain_length < 4) {
+			/*
+			 * Yes.  Tell the TCP dissector where the data for
+			 * this message starts in the data it handed us and
+			 * that we need "some more data."  Don't tell it
+			 * exactly how many bytes we need because if/when we
+			 * ask for even more (after the header) that will
+			 * break reassembly.
+			 */
                 	pinfo->desegment_offset = offset;
-                	pinfo->desegment_len = 4-remain_length;
+                	pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                 	*need_desegmentation = TRUE;
                 	return offset;
 		}
@@ -636,10 +651,25 @@ ssh_dissect_key_exchange(tvbuff_t *tvb, packet_info *pinfo,
 	 * This means we're guaranteed that "remain_length" is positive.
 	 */
 	remain_length = tvb_ensure_length_remaining(tvb,offset);
+	/*
+	 * Can we do reassembly?
+	 */
 	if (ssh_desegment && pinfo->can_desegment) {
+		/*
+		 * Yes - would an SSH header starting at this offset
+		 * be split across segment boundaries?
+		 */
 		if(remain_length < 4) {
+			/*
+			 * Yes.  Tell the TCP dissector where the data for
+			 * this message starts in the data it handed us and
+			 * that we need "some more data."  Don't tell it
+			 * exactly how many bytes we need because if/when we
+			 * ask for even more (after the header) that will
+			 * break reassembly.
+			 */
                 	pinfo->desegment_offset = offset;
-                	pinfo->desegment_len = 4-remain_length;
+                	pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                 	*need_desegmentation = TRUE;
                 	return offset;
 		}
diff --git a/epan/dissectors/packet-ssl.c b/epan/dissectors/packet-ssl.c
index 203aaeaa32..39959e02c0 100644
--- a/epan/dissectors/packet-ssl.c
+++ b/epan/dissectors/packet-ssl.c
@@ -1322,12 +1322,10 @@ dissect_ssl3_record(tvbuff_t *tvb, packet_info *pinfo,
         if (available_bytes < 5) {
             /*
              * Yes.  Tell the TCP dissector where the data for this
-             * message starts in the data it handed us, and how many
-             * more bytes we need, and return.
-             * Fix for bug 4535: Don't get just the data we need, get
-             * one more segment. Otherwise when the next segment does
-             * not contain all the rest of the SSL PDU, reassembly will
-             * break.
+             * message starts in the data it handed us, and that we need
+             * "some more data."  Don't tell it exactly how many bytes we
+             * need because if/when we ask for even more (after the header)
+             * that will break reassembly.
              */
             pinfo->desegment_offset = offset;
             pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
@@ -1366,7 +1364,8 @@ dissect_ssl3_record(tvbuff_t *tvb, packet_info *pinfo,
                  * the continuation of a previous PDU together with a full new
                  * PDU (and the info column would not show the message type
                  * of the second PDU)
-                */
+                 */
+
                 pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                 *need_desegmentation = TRUE;
                 return offset;
@@ -2811,11 +2810,11 @@ dissect_ssl2_record(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     byte = tvb_get_guint8(tvb, offset);
     record_length_length = (byte & 0x80) ? 2 : 3;
 
+    available_bytes = tvb_length_remaining(tvb, offset);
+
     /*
      * Can we do reassembly?
      */
-    available_bytes = tvb_length_remaining(tvb, offset);
-
     if (ssl_desegment && pinfo->can_desegment) {
         /*
          * Yes - is the record header split across segment boundaries?
@@ -2823,11 +2822,13 @@ dissect_ssl2_record(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
         if (available_bytes < record_length_length) {
             /*
              * Yes.  Tell the TCP dissector where the data for this
-             * message starts in the data it handed us, and how many
-             * more bytes we need, and return.
+             * message starts in the data it handed us, and that we need
+             * "some more data."  Don't tell it exactly how many bytes we
+             * need because if/when we ask for even more (after the header)
+             * that will break reassembly.
              */
             pinfo->desegment_offset = offset;
-            pinfo->desegment_len = record_length_length - available_bytes;
+            pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT; 
             *need_desegmentation = TRUE;
             return offset;
         }
diff --git a/epan/dissectors/packet-tcp.c b/epan/dissectors/packet-tcp.c
index bd8dba4f15..4ce527e5d3 100644
--- a/epan/dissectors/packet-tcp.c
+++ b/epan/dissectors/packet-tcp.c
@@ -2070,8 +2070,10 @@ tcp_dissect_pdus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
             if (length_remaining < fixed_len) {
                 /*
                  * Yes.  Tell the TCP dissector where the data for this message
-                 * starts in the data it handed us, and how many more bytes we
-                 * need, and return.
+                 * starts in the data it handed us and that we need "some more
+                 * data."  Don't tell it exactly how many bytes we need because
+                 * if/when we ask for even more (after the header) that will
+                 * break reassembly.
                  */
                 pinfo->desegment_offset = offset;
                 pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
diff --git a/epan/dissectors/packet-tds.c b/epan/dissectors/packet-tds.c
index 0550096fe3..2686fbcaf1 100644
--- a/epan/dissectors/packet-tds.c
+++ b/epan/dissectors/packet-tds.c
@@ -2402,14 +2402,15 @@ dissect_tds_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
              * split across segment boundaries?
              */
             if (length_remaining < 8) {
-                /*
-                 * Yes.  Tell the TCP dissector where the
-                 * data for this message starts in the data
-                 * it handed us, and how many more bytes we
-                 * need, and return.
-                 */
+		/*
+		 * Yes.  Tell the TCP dissector where the data for this message
+		 * starts in the data it handed us and that we need "some more
+		 * data."  Don't tell it exactly how many bytes we need because
+		 * if/when we ask for even more (after the header) that will
+		 * break reassembly.
+		 */
                 pinfo->desegment_offset = offset;
-                pinfo->desegment_len = 8 - length_remaining;
+                pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                 return;
             }
         }
diff --git a/epan/dissectors/packet-tpkt.c b/epan/dissectors/packet-tpkt.c
index 40ddb58a74..d5001a6282 100644
--- a/epan/dissectors/packet-tpkt.c
+++ b/epan/dissectors/packet-tpkt.c
@@ -432,13 +432,15 @@ dissect_tpkt_encap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 			 */
 			if (length_remaining < 4) {
 				/*
-				 * Yes.  Tell the TCP dissector where
-				 * the data for this message starts in
-				 * the data it handed us, and how many
-				 * more bytes we need, and return.
+				 * Yes.  Tell the TCP dissector where the data
+				 * for this message starts in the data it
+				 * handed us and that we need "some more data."
+				 * Don't tell it exactly how many bytes we need
+				 * because if/when we ask for even more (after
+				 * the header) that will break reassembly.
 				 */
 				pinfo->desegment_offset = offset;
-				pinfo->desegment_len = 4 - length_remaining;
+				pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
 				return;
 			}
 		}
diff --git a/epan/dissectors/packet-x11.c b/epan/dissectors/packet-x11.c
index a05dc2a814..f700b8a77c 100644
--- a/epan/dissectors/packet-x11.c
+++ b/epan/dissectors/packet-x11.c
@@ -4338,10 +4338,13 @@ static void dissect_x11_requests(tvbuff_t *tvb, packet_info *pinfo,
                         /*
                          * Yes.  Tell the TCP dissector where the data
                          * for this message starts in the data it handed
-                         * us, and how many more bytes we need, and return.
+                         * us and that we need "some more data."  Don't tell
+                         * it exactly how many bytes we need because if/when
+                         * we ask for even more (after the header) that will
+                         * break reassembly.
                          */
                         pinfo->desegment_offset = offset;
-                        pinfo->desegment_len = 4 - length_remaining;
+                        pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                         return;
                   }
             }
@@ -4450,11 +4453,13 @@ static void dissect_x11_requests(tvbuff_t *tvb, packet_info *pinfo,
                               /*
                                * Yes.  Tell the TCP dissector where the
                                * data for this message starts in the data
-                               * it handed us, and how many more bytes we
-                               * need, and return.
+                               * it handed us and that we need "some more
+                               * data."  Don't tell it exactly how many bytes
+                               * we need because if/when we ask for even more
+                               * (after the header) that will break reassembly.
                                */
                               pinfo->desegment_offset = offset;
-                              pinfo->desegment_len = 10 - length_remaining;
+                              pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                               return;
                         }
                   }
@@ -4699,11 +4704,13 @@ dissect_x11_replies(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
                         /*
                          * Yes.  Tell the TCP dissector where the data
                          * for this message starts in the data it handed
-                         * us, and how many more bytes we need, and
-                         * return.
+                         * us and that we need "some more data."  Don't tell
+                         * it exactly how many bytes we need because if/when
+                         * we ask for even more (after the header) that will
+                         * break reassembly.
                          */
                         pinfo->desegment_offset = offset;
-                        pinfo->desegment_len = 8 - length_remaining;
+                        pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
                         return;
                   }
             }