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GVCP: Fix an infinite loop. 

Remove an "if(tree)" test in order to ensure that our offset always
advances.

Bug: 16029
Change-Id: I5bb38f2eccfbf3c44a06682a17aafcba9d8fa0c6
Reviewed-on: https://code.wireshark.org/review/37611
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Gerald Combs 2020-06-29 15:19:19 -07:00 committed by Anders Broman
parent 5258ceadb3
commit d70bd4489f
1 changed files with 55 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

113
epan/dissectors/packet-gvcp.c
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@ -2014,74 +2014,71 @@ static void dissect_eventdata_cmd(proto_tree *gvcp_telegram_tree, tvbuff_t *tvb,
/* fill in Info column in Wireshark GUI */
col_append_fstr(pinfo->cinfo, COL_INFO, "[ID: 0x%04X]", eventid);
if (gvcp_telegram_tree != NULL)
/* If extended ID, then we have event_size here (2.1) */
if (extendedblockids)
{
/* If extended ID, then we have event_size here (2.1) */
if (extendedblockids)
{
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_extid_length, tvb, offset, 2, ENC_BIG_ENDIAN);
data_length = tvb_get_ntohs(tvb, offset); // We get the data length here
}
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_extid_length, tvb, offset, 2, ENC_BIG_ENDIAN);
data_length = tvb_get_ntohs(tvb, offset); // We get the data length here
}
/* skip reserved field */
/* skip reserved field */
offset += 2;
/* Use range to determine type of event */
if ((eventid >= 0x0000) && (eventid <= 0x8000))
{
/* Standard ID */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
else if ((eventid >= 0x8001) && (eventid <= 0x8FFF))
{
/* Error */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_error_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
else if ((eventid >= 0x9000) && (eventid <= 0xFFFF))
{
/* Device specific */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_device_specific_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
offset += 2;
/* Stream channel (possibly) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_stream_channel_index, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
if (extendedblockids == 0)
{
/* Block id (16 bit) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_block_id, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
/* Use range to determine type of event */
if ((eventid >= 0x0000) && (eventid <= 0x8000))
{
/* Standard ID */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
else if ((eventid >= 0x8001) && (eventid <= 0x8FFF))
{
/* Error */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_error_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
else if ((eventid >= 0x9000) && (eventid <= 0xFFFF))
{
/* Device specific */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_device_specific_id, tvb, offset, 2, ENC_BIG_ENDIAN);
}
}
else
{
offset += 2;
/* Stream channel (possibly) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_stream_channel_index, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
if (extendedblockids == 0)
{
/* Block id (16 bit) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_block_id, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
else
{
offset += 2;
/* Block id (64 bit) only if reported by gvcp flag */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_block_id_64bit_v2_0, tvb, offset, 8, ENC_BIG_ENDIAN);
offset += 8;
}
/* Timestamp (64 bit) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_timestamp, tvb, offset, 8, ENC_BIG_ENDIAN);
/* Block id (64 bit) only if reported by gvcp flag */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_block_id_64bit_v2_0, tvb, offset, 8, ENC_BIG_ENDIAN);
offset += 8;
}
if (extendedblockids)
{
if (data_length > 24)
{
/* Data */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_data, tvb, offset, data_length - 24, ENC_NA);
offset += data_length - 24;
}
}
else
/* Timestamp (64 bit) associated with event */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_timestamp, tvb, offset, 8, ENC_BIG_ENDIAN);
offset += 8;
if (extendedblockids)
{
if (data_length > 24)
{
/* Data */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_data, tvb, offset, -1, ENC_NA);
return;
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_data, tvb, offset, data_length - 24, ENC_NA);
offset += data_length - 24;
}
}
else
{
/* Data */
proto_tree_add_item(gvcp_telegram_tree, hf_gvcp_eventcmd_data, tvb, offset, -1, ENC_NA);
return;
}
}
}