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Make RX a new style dissector: return 0 if there isn't at least 28 bytes of message or if it receives an unknown Type. Add a check of tvb length to README.developer's cut-n-paste dissector code. 

svn path=/trunk/; revision=21300
This commit is contained in:
Jeff Morriss 2007-04-02 08:25:43 +00:00
parent 98cc46f2a4
commit a5f4e7b85a
2 changed files with 15 additions and 2 deletions
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3
doc/README.developer
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@ -733,6 +733,9 @@ dissect_PROTOABBREV(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
* if someone analyzed that web server's traffic in Wireshark, would result
* in Wireshark handing an HTTP packet to your dissector). For example:
*/
/* Check that there's enough data */
if (tvb_length(tvb) < /* your protocol's smallest packet size */)
return 0;
/* Get some values from the packet header, probably using tvb_get_*() */
if ( /* these values are not possible in PROTONAME */ )

14
epan/dissectors/packet-rx.c
View File

@ -452,7 +452,7 @@ dissect_rx_flags(tvbuff_t *tvb, struct rxinfo *rxinfo, proto_tree *parent_tree,
return offset;
}
static void
static int
dissect_rx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
{
proto_tree *tree;
@ -463,6 +463,15 @@ dissect_rx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
guint32 seq, callnumber;
guint16 serviceid;
/* Ensure we have enough data */
if (tvb_length(tvb) < 28)
return 0;
/* Make sure it's a known type */
type = tvb_get_guint8(tvb, 20);
if (type == 0 || type == 10 || type == 11 || type == 12 || type > 13)
return 0;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "RX");
if (check_col(pinfo->cinfo, COL_INFO))
@ -582,6 +591,7 @@ dissect_rx(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
break;
}
return(tvb_length(tvb));
}
void
@ -784,7 +794,7 @@ proto_reg_handoff_rx(void)
/* Ports in the range UDP_PORT_RX_LOW to UDP_PORT_RX_HIGH
are all used for various AFS services. */
rx_handle = create_dissector_handle(dissect_rx, proto_rx);
rx_handle = new_create_dissector_handle(dissect_rx, proto_rx);
for (port = UDP_PORT_RX_LOW; port <= UDP_PORT_RX_HIGH; port++)
dissector_add("udp.port", port, rx_handle);
dissector_add("udp.port", UDP_PORT_RX_AFS_BACKUPS, rx_handle);