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CIP: Highlight correct bytes in Req/Rsp processing 

Previously, dissect_cip_generic_service_req and dissect_cip_generic_service_rsp
set lengths at different levels of the packet. In some cases, this would
cause a malformed packet when the data length was zero. This fixes the
malformed error by explicitly setting the length, instead of using -1.

The length of the service data set is not the data paylod for both
cases. Previously, for requests, it attempted to highlight the whole CIP
layer, but this was already covered by the full CIP protocol layer
length.

Change-Id: I4b4a99d30b9e04872fcf7ffb127c496e6062856c
Reviewed-on: https://code.wireshark.org/review/25672
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot
Reviewed-by: Michael Mann <mmann78@netscape.net>
This commit is contained in:
Dylan Ulis 2018-02-07 16:34:11 -05:00 committed by Michael Mann
parent 60c5ec67f8
commit e4c5efafb7
1 changed files with 9 additions and 5 deletions
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14
epan/dissectors/packet-cip.c
View File

@ -5541,14 +5541,14 @@ dissect_cip_generic_service_req(tvbuff_t *tvb, packet_info *pinfo, proto_tree *t
add_cip_service_to_info_column(pinfo, service, cip_sc_vals);
req_path_size = tvb_get_guint8(tvb, offset + 1);
offset += ((req_path_size * 2) + 2);
/* Create service tree */
cmd_data_tree = proto_tree_add_subtree(tree, tvb, 0, -1, ett_cmd_data, &cmd_data_item,
cmd_data_tree = proto_tree_add_subtree(tree, tvb, offset, 0, ett_cmd_data, &cmd_data_item,
val_to_str(service, cip_sc_vals , "Unknown Service (0x%02x)"));
proto_item_append_text(cmd_data_item, " (Request)");
req_path_size = tvb_get_guint8( tvb, offset+1);
offset += ((req_path_size*2)+2);
int parsed_len = 0;
switch(service)
@ -5589,6 +5589,8 @@ dissect_cip_generic_service_req(tvbuff_t *tvb, packet_info *pinfo, proto_tree *t
proto_tree_add_item(cmd_data_tree, hf_cip_data, tvb, offset + parsed_len, remain_len, ENC_NA);
}
proto_item_set_len(cmd_data_item, parsed_len + remain_len);
return tvb_reported_length(tvb);
}
@ -5931,7 +5933,7 @@ dissect_cip_generic_service_rsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *t
add_cip_service_to_info_column(pinfo, service, cip_sc_vals);
cmd_data_tree = proto_tree_add_subtree(tree, tvb, offset, -1,
cmd_data_tree = proto_tree_add_subtree(tree, tvb, offset, 0,
ett_cmd_data, &cmd_data_item, val_to_str(service, cip_sc_vals, "Unknown Service (0x%02x)"));
proto_item_append_text(cmd_data_item, " (Response)");
@ -5984,6 +5986,8 @@ dissect_cip_generic_service_rsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *t
proto_tree_add_item(cmd_data_tree, hf_cip_data, tvb, offset + parsed_len, remain_len, ENC_NA);
}
proto_item_set_len(cmd_data_item, parsed_len + remain_len);
return tvb_reported_length(tvb);
}