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GSM over IP: Require a valid message type for dissection. 

Protects against some false positives because by default GSM over IP
claims some "frequently used" ports.

Change-Id: I94736ecef8ac1422bb330a364a3f77edd9a52a2b
Reviewed-on: https://code.wireshark.org/review/31265
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Michael Mann 2018-12-30 11:19:13 -05:00 committed by Anders Broman
parent a88d60509d
commit 080ff63a00
1 changed files with 24 additions and 10 deletions
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34
epan/dissectors/packet-gsm_ipa.c
View File

@ -112,12 +112,12 @@ static dissector_table_t osmo_dissector_table;
static const value_string ipa_protocol_vals[] = {
{ 0x00, "RSL" },
{ 0xdd, "HSL Debug" },
{ 0xee, "OSMO EXT" },
{ 0xfc, "MGCP (old)" },
{ 0xfd, "SCCP" },
{ 0xfe, "IPA" },
{ 0xff, "OML" },
{ HSL_DEBUG, "HSL Debug" },
{ OSMO_EXT, "OSMO EXT" },
{ IPA_MGCP, "MGCP (old)" },
{ AIP_SCCP, "SCCP" },
{ ABISIP_IPACCESS, "IPA" },
{ ABISIP_OML, "OML" },
{ 0, NULL }
};
@ -259,12 +259,22 @@ dissect_osmo(tvbuff_t *tvb, packet_info *pinfo, proto_tree *ipatree, proto_tree
/* Code to actually dissect the packets */
static void
static gboolean
dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean is_udp)
{
gint remaining;
gint header_length = 3;
int offset = 0;
guint16 len, msg_type;
if (tvb_reported_length(tvb) < 4)
return FALSE;
//sanity check the message type
msg_type = tvb_get_guint8(tvb, 2);
if ((try_val_to_str(msg_type, ipa_protocol_vals) == NULL) &&
(msg_type >= ABISIP_RSL_MAX))
return FALSE;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "IPA");
col_clear(pinfo->cinfo, COL_INFO);
@ -272,7 +282,6 @@ dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean is_udp
while ((remaining = tvb_reported_length_remaining(tvb, offset)) > 0) {
proto_item *ti;
proto_tree *ipa_tree = NULL;
guint16 len, msg_type;
tvbuff_t *next_tvb;
len = tvb_get_ntohs(tvb, offset);
@ -345,19 +354,24 @@ dissect_ipa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean is_udp
}
offset += len + header_length;
}
return TRUE;
}
static int
dissect_ipa_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
dissect_ipa(tvb, pinfo, tree, FALSE);
if (!dissect_ipa(tvb, pinfo, tree, FALSE))
return 0;
return tvb_captured_length(tvb);
}
static int
dissect_ipa_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
dissect_ipa(tvb, pinfo, tree, TRUE);
if (!dissect_ipa(tvb, pinfo, tree, TRUE))
return 0;
return tvb_captured_length(tvb);
}