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telnet: full START_TLS support 

Assumes that the source and destination ports are different (or else
some packets may be wrongly dissected as TLS instead of telnet). SSL
does something similar.

Bug: 11874
Change-Id: Ibf6d3ce2950cb5745c33716db21005cd28bf603b
Reviewed-on: https://code.wireshark.org/review/12652
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Peter Wu 2015-12-15 14:10:15 +01:00 committed by Anders Broman
parent e3dd3f97f1
commit 4d17b275e7
1 changed files with 34 additions and 0 deletions
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34
epan/dissectors/packet-telnet.c
View File

@ -31,6 +31,7 @@
#include <epan/expert.h>
#include <epan/asn1.h>
#include "packet-kerberos.h"
#include "packet-ssl-utils.h"
#include "packet-tn3270.h"
#include "packet-tn5250.h"
@ -148,6 +149,7 @@ static dissector_handle_t telnet_handle;
static dissector_handle_t tn3270_handle;
static dissector_handle_t tn5250_handle;
static dissector_handle_t ssl_handle;
/* Some defines for Telnet */
@ -214,6 +216,11 @@ typedef struct tn_opt {
/* routine to dissect option */
} tn_opt;
typedef struct _telnet_conv_info {
guint32 starttls_requested_in; /* Frame of first sender of START_TLS FOLLOWS */
guint32 starttls_port; /* Source port for first sender */
} telnet_conv_info_t;
static void
check_tn3270_model(packet_info *pinfo _U_, const char *terminaltype)
{
@ -254,6 +261,20 @@ check_for_tn3270(packet_info *pinfo _U_, const char *optname, const char *termin
add_tn5250_conversation(pinfo, 0);
}
static telnet_conv_info_t *
telnet_get_session(packet_info *pinfo)
{
conversation_t *conversation = find_or_create_conversation(pinfo);
telnet_conv_info_t *telnet_info;
telnet_info = (telnet_conv_info_t*)conversation_get_proto_data(conversation, proto_telnet);
if (!telnet_info) {
telnet_info = wmem_new0(wmem_file_scope(), telnet_conv_info_t);
conversation_add_proto_data(conversation, proto_telnet, telnet_info);
}
return telnet_info;
}
static void
dissect_string_subopt(packet_info *pinfo, const char *optname, tvbuff_t *tvb, int offset, int len,
proto_tree *tree, proto_item *item)
@ -455,7 +476,19 @@ static void
dissect_starttls_subopt(packet_info *pinfo _U_, const char *optname _U_, tvbuff_t *tvb, int offset,
int len _U_, proto_tree *tree, proto_item *item _U_)
{
telnet_conv_info_t *session = telnet_get_session(pinfo);
proto_tree_add_item(tree, hf_telnet_starttls, tvb, offset, 1, ENC_BIG_ENDIAN);
if (session->starttls_requested_in == 0) {
/* First sender (client or server) requesting to start TLS. */
session->starttls_requested_in = pinfo->fd->num;
session->starttls_port = pinfo->srcport;
} else if (session->starttls_requested_in < pinfo->fd->num &&
session->starttls_port != pinfo->srcport) {
/* Other side confirms that following data is TLS. */
ssl_starttls_ack(ssl_handle, pinfo, telnet_handle);
}
}
static const value_string telnet_outmark_subopt_cmd_vals[] = {
@ -2165,6 +2198,7 @@ proto_reg_handoff_telnet(void)
dissector_add_uint("tcp.port", TCP_PORT_TELNET, telnet_handle);
tn3270_handle = find_dissector("tn3270");
tn5250_handle = find_dissector("tn5250");
ssl_handle = find_dissector("ssl");
}
/*