Ethereal-dev: [Ethereal-dev] [PATCH]Dissecting SSH short frames

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From: Loïc Minier <lool+ethereal@xxxxxxxxxx>
Date: Thu, 18 Dec 2003 21:27:29 +0100
     Hi list!

 It turns out that packet-ssh.c loops forever if the first packets
 are short frames (the announced TCP payload is bigger than the real
 captured payload, for example because one forgot to -s 65535 with
 tcpdump :).

 Attached patch replaces the tvb_reported_length_remaining calls with
 tvb_ensure_length_remaining calls, and fixes the problem here.

 As a side note, I'm not sure packet-ssh.c takes all cases in account,
 for example my first workaround was to add an else block at line 329,
 now it seems this isn't needed anymore but I did not check all possible
 cases.

-- 
Lo�c Minier <lool@xxxxxxxx>
Index: packet-ssh.c
===================================================================
RCS file: /cvsroot/ethereal/packet-ssh.c,v
retrieving revision 1.7
diff -u -r1.7 packet-ssh.c
--- packet-ssh.c	17 Apr 2003 07:39:18 -0000	1.7
+++ packet-ssh.c	18 Dec 2003 19:01:17 -0000
@@ -295,7 +295,7 @@
 		return;
 	}
 			
-	while((remain_length = tvb_reported_length_remaining(tvb,offset))> 0 ) {
+	while((remain_length = tvb_ensure_length_remaining(tvb,offset))> 0 ) {
 		need_desegmentation = FALSE;
 		last_offset = offset;
 		this_number = this_data->counter+number;
@@ -573,7 +573,7 @@
 
 	/* MAC , if there is still bytes, treat it as 16bytes MAC*/
 	if(msg_code == SSH2_MSG_KEX_DH_GEX_REPLY) {
-		len = tvb_reported_length_remaining(tvb,offset);
+		len = tvb_ensure_length_remaining(tvb,offset);
 		if(len == 16) {
 			if(tree) {
 				proto_tree_add_item(key_ex_tree, hf_ssh_mac_string,
@@ -591,7 +591,7 @@
 {
 	gint len;
 
-	len = tvb_reported_length_remaining(tvb,offset);
+	len = tvb_ensure_length_remaining(tvb,offset);
 	if (check_col(pinfo->cinfo, COL_INFO)) {
   		col_add_fstr(pinfo->cinfo, COL_INFO, "Encrypted %s packet len=%d", 
 			is_response?"response":"request",len);