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From Jon Ringle: 

don't dissect attributes if there aren't any;

	put each attribute into a subtree;

	register the dissector by name.

Use "match_strval()" to check whether the message type is a known STUN
message type, and to generate the message type for the Info column.

Don't use "tvb_bytes_exist()" to check when we run out of data - use the
length fields from the packet.  Check the sanity of those lengths, too.

svn path=/trunk/; revision=13063
This commit is contained in:
Guy Harris 2005-01-16 04:25:27 +00:00
parent 5485b96a9a
commit d1ae7c688f
2 changed files with 79 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
AUTHORS
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@ -2369,6 +2369,7 @@ Tomasz Mrugalski <thomson [AT] klub.com.pl>
Brett Kuskie <mstrprgmmr [AT] chek.com>
Brian Caswell <bmc [AT] sourcefire.com>
Yann <yann_eads [AT] hotmail.com>
Jon Ringle <ml-ethereal [AT] ringle.org>
Alain Magloire <alainm[AT]rcsm.ece.mcgill.ca> was kind enough to
give his permission to use his version of snprintf.c.

160
epan/dissectors/packet-stun.c
View File

@ -89,6 +89,7 @@ static int stun_att_error_reason = -1;
/* Initialize the subtree pointers */
static gint ett_stun = -1;
static gint ett_stun_att_type = -1;
static gint ett_stun_att = -1;
@ -141,10 +142,15 @@ dissect_stun(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_item *ti;
proto_item *ta;
proto_tree *stun_tree;
proto_tree *att_type_tree;
proto_tree *att_tree;
guint16 msg_type;
guint16 msg_length;
char *msg_type_str;
guint16 att_type;
guint16 att_length;
guint16 offset;
guint i;
/*
* First check if the frame is really meant for us.
@ -154,26 +160,21 @@ dissect_stun(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
if (!tvb_bytes_exist(tvb, 0, STUN_HDR_LEN))
return 0;
att_type = tvb_get_ntohs(tvb, 0);
msg_type = tvb_get_ntohs(tvb, 0);
/* check if message type is correct */
if( (att_type != BINDING_REQUEST) &&
(att_type != BINDING_RESPONSE) &&
(att_type != BINDING_ERROR_RESPONSE) &&
(att_type != SHARED_SECRET_REQUEST) &&
(att_type != SHARED_SECRET_RESPONSE) &&
(att_type != SHARED_SECRET_ERROR_RESPONSE)
)
msg_type_str = match_strval(msg_type, messages);
if (msg_type_str == NULL)
return 0;
att_length = tvb_get_ntohs(tvb, 2);
msg_length = tvb_get_ntohs(tvb, 2);
/* check if payload enough */
if (!tvb_bytes_exist(tvb, 0, STUN_HDR_LEN+att_length))
if (!tvb_bytes_exist(tvb, 0, STUN_HDR_LEN+msg_length))
return 0;
if(tvb_bytes_exist(tvb, 0, STUN_HDR_LEN+att_length+1))
/* Check if too much payload */
if (tvb_bytes_exist(tvb, 0, STUN_HDR_LEN+msg_length+1))
return 0;
/* The message seems to be a valid STUN message! */
@ -182,115 +183,106 @@ dissect_stun(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
col_set_str(pinfo->cinfo, COL_PROTOCOL, "STUN");
if (check_col(pinfo->cinfo, COL_INFO)) {
col_clear(pinfo->cinfo, COL_INFO);
col_add_fstr(pinfo->cinfo, COL_INFO, "Message : %s",
(att_type==BINDING_REQUEST)?"Binding Request":
(att_type==BINDING_RESPONSE)?"Binding Response":
(att_type==BINDING_ERROR_RESPONSE)?"Binding Error Response":
(att_type==SHARED_SECRET_REQUEST)?"Shared Secret Request":
(att_type==SHARED_SECRET_RESPONSE)?"Shared Secret Response":
(att_type==SHARED_SECRET_ERROR_RESPONSE)?"Shared Secret Error Response":"UNKNOWN"
);
col_add_fstr(pinfo->cinfo, COL_INFO, "Message: %s",
msg_type_str);
}
if (tree) {
ti = proto_tree_add_item(tree, proto_stun, tvb, 0, -1, FALSE);
stun_tree = proto_item_add_subtree(ti, ett_stun);
proto_tree_add_item(stun_tree, hf_stun_type, tvb, 0, 2, FALSE);
proto_tree_add_item(stun_tree, hf_stun_length, tvb, 2, 2, FALSE);
proto_tree_add_uint(stun_tree, hf_stun_type, tvb, 0, 2, msg_type);
proto_tree_add_uint(stun_tree, hf_stun_length, tvb, 2, 2, msg_length);
proto_tree_add_item(stun_tree, hf_stun_id, tvb, 4, 16, FALSE);
ta = proto_tree_add_item(stun_tree, hf_stun_att, tvb, STUN_HDR_LEN, -1, FALSE);
att_tree = proto_item_add_subtree(ta, ett_stun_att);
if (msg_length > 0) {
ta = proto_tree_add_item(stun_tree, hf_stun_att, tvb, STUN_HDR_LEN, msg_length, FALSE);
att_type_tree = proto_item_add_subtree(ta, ett_stun_att_type);
offset = STUN_HDR_LEN;
offset = STUN_HDR_LEN;
while(1){
if( !tvb_bytes_exist(tvb, offset, ATTR_HDR_LEN) ) /* no data anymore */
break;
while( msg_length > 0) {
att_type = tvb_get_ntohs(tvb, offset); /* Type field in attribute header */
att_length = tvb_get_ntohs(tvb, offset+2); /* Length field in attribute header */
ta = proto_tree_add_text(att_type_tree, tvb, offset,
ATTR_HDR_LEN+att_length,
"Attribute: %s",
val_to_str(att_type, attributes, "Unknown (0x%04x)"));
att_tree = proto_item_add_subtree(ta, ett_stun_att);
proto_tree_add_uint(att_tree, stun_att_type, tvb,
offset, 2, att_type);
offset += 2;
if (ATTR_HDR_LEN+att_length > msg_length) {
proto_tree_add_uint_format(att_tree,
stun_att_length, tvb, offset, 2,
att_length,
"Attribute Length: %u (bogus, goes past the end of the message)",
att_length);
break;
}
proto_tree_add_uint(att_tree, stun_att_length, tvb,
offset, 2, att_length);
offset += 2;
switch( att_type ){
case MAPPED_ADDRESS:
case RESPONSE_ADDRESS:
case SOURCE_ADDRESS:
case CHANGED_ADDRESS:
case REFLECTED_FROM:
proto_tree_add_item(att_tree, stun_att_type, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_length, tvb, offset+2, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_family, tvb, offset+5, 1, FALSE);
proto_tree_add_item(att_tree, stun_att_port, tvb, offset+6, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_ip, tvb, offset+8, 4, FALSE);
offset = offset+(ATTR_HDR_LEN+att_length);
if (att_length < 2)
break;
proto_tree_add_item(att_tree, stun_att_family, tvb, offset+1, 1, FALSE);
if (att_length < 4)
break;
proto_tree_add_item(att_tree, stun_att_port, tvb, offset+2, 2, FALSE);
if (att_length < 8)
break;
proto_tree_add_item(att_tree, stun_att_ip, tvb, offset+4, 4, FALSE);
break;
case CHANGE_REQUEST:
proto_tree_add_item(att_tree, stun_att_type, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_length, tvb, offset+2, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_change_ip, tvb, offset+4, 4, FALSE);
proto_tree_add_item(att_tree, stun_att_change_port, tvb, offset+4, 4, FALSE);
offset = offset+(ATTR_HDR_LEN+att_length);
if (att_length < 4)
break;
proto_tree_add_item(att_tree, stun_att_change_ip, tvb, offset, 4, FALSE);
proto_tree_add_item(att_tree, stun_att_change_port, tvb, offset, 4, FALSE);
break;
case USERNAME:
case PASSWORD:
case MESSAGE_INTEGRITY:
proto_tree_add_item(att_tree, stun_att_type, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_length, tvb, offset+2, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_value, tvb, offset+4, att_length, FALSE);
offset = offset+(ATTR_HDR_LEN+att_length);
if (att_length < 1)
break;
proto_tree_add_item(att_tree, stun_att_value, tvb, offset, att_length, FALSE);
break;
case ERROR_CODE:
proto_tree_add_item(att_tree, stun_att_type, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_length, tvb, offset+2, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_error_class, tvb, offset+6, 1, FALSE);
proto_tree_add_item(att_tree, stun_att_error_number, tvb, offset+7, 1, FALSE);
if (att_length < 3)
break;
proto_tree_add_item(att_tree, stun_att_error_class, tvb, offset+2, 1, FALSE);
if (att_length < 4)
break;
proto_tree_add_item(att_tree, stun_att_error_number, tvb, offset+3, 1, FALSE);
if (att_length < 5)
break;
proto_tree_add_item(att_tree, stun_att_error_reason, tvb, offset+8, (att_length-4), FALSE);
offset = offset+(ATTR_HDR_LEN+att_length);
break;
break;
case UNKNOWN_ATTRIBUTES:
proto_tree_add_item(att_tree, stun_att_type, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_length, tvb, offset+2, 2, FALSE);
offset = offset + ATTR_HDR_LEN;
while(tvb_bytes_exist(tvb, offset, 4)){ /* UNKNOWN-ATTRIBUTES is 4 bytes aligned */
proto_tree_add_item(att_tree, stun_att_unknown, tvb, offset, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_unknown, tvb, offset+2, 2, FALSE);
offset = offset + 4;
for (i = 0; i < att_length; i += 4) {
proto_tree_add_item(att_tree, stun_att_unknown, tvb, offset+i, 2, FALSE);
proto_tree_add_item(att_tree, stun_att_unknown, tvb, offset+i+2, 2, FALSE);
}
break;
default:
return tvb_length(tvb);
break;
}
offset += att_length;
msg_length -= ATTR_HDR_LEN+att_length;
}
}
}
return tvb_length(tvb);
@ -383,6 +375,7 @@ proto_register_stun(void)
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_stun,
&ett_stun_att_type,
&ett_stun_att,
};
@ -393,6 +386,8 @@ proto_register_stun(void)
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_stun, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
new_register_dissector("stun", dissect_stun, proto_stun);
}
@ -401,7 +396,8 @@ proto_reg_handoff_stun(void)
{
dissector_handle_t stun_handle;
stun_handle = new_create_dissector_handle(dissect_stun, proto_stun);
stun_handle = find_dissector("stun");
dissector_add("tcp.port", TCP_PORT_STUN, stun_handle);
dissector_add("udp.port", UDP_PORT_STUN, stun_handle);