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And it happens again... 

In Yet Another Protocol, implementation A neglected to set the padding bytes
to 0 and implementation B barfed on said padding (interestingly this
protocol's spec does not include the IETF-normal "receiver MUST ignore the
padding" blurb).

So:

Add the AVP to the dissection tree and add an expert info for when it's not
zero.

Also re-order a few of the hfs and remove a couple unneeded temporary
variables.

svn path=/trunk/; revision=48488
This commit is contained in:
Jeff Morriss 2013-03-22 18:13:31 +00:00
parent 1b5350b10a
commit 5c39978e35
1 changed files with 41 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
epan/dissectors/packet-diameter.c
View File

@ -256,6 +256,7 @@ static int hf_diameter_avp_flags_reserved6 = -1;
static int hf_diameter_avp_flags_reserved7 = -1;
static int hf_diameter_avp_vendor_id = -1;
static int hf_diameter_avp_data_wrong_length = -1;
static int hf_diameter_avp_pad = -1;
static int hf_diameter_answer_in = -1;
static int hf_diameter_answer_to = -1;
@ -393,7 +394,10 @@ dissect_diameter_avp(diam_ctx_t *c, tvbuff_t *tvb, int offset)
diam_vnd_t *vendor;
const char *code_str;
const char *avp_str;
guint8 pad_len;
len &= 0x00ffffff;
pad_len = (len % 4) ? 4 - (len % 4) : 0 ;
if (!a) {
a = &unknown_avp;
@ -435,12 +439,12 @@ dissect_diameter_avp(diam_ctx_t *c, tvbuff_t *tvb, int offset)
/* Code */
if (a == &unknown_avp) {
proto_tree *tu = proto_item_add_subtree(pi,ett_unknown);
proto_item *iu = proto_tree_add_text(tu,tvb,offset,4,"Unknown AVP, "
"if you know what this is you can add it to dictionary.xml");
expert_add_info_format(c->pinfo, iu, PI_UNDECODED, PI_WARN,
pi = proto_tree_add_text(tu,tvb,offset,4,"Unknown AVP, "
"if you know what this is you can add it to dictionary.xml");
expert_add_info_format(c->pinfo, pi, PI_UNDECODED, PI_WARN,
"Unknown AVP %u (vendor=%s)", code,
val_to_str_ext_const(vendorid, &sminmpec_values_ext, "Unknown"));
PROTO_ITEM_SET_GENERATED(iu);
PROTO_ITEM_SET_GENERATED(pi);
}
offset += 4;
@ -477,23 +481,25 @@ dissect_diameter_avp(diam_ctx_t *c, tvbuff_t *tvb, int offset)
pi = proto_tree_add_item(avp_tree,hf_diameter_avp_vendor_id,tvb,offset,4,ENC_BIG_ENDIAN);
if (vendor == &unknown_vendor) {
proto_tree *tu = proto_item_add_subtree(pi,ett_unknown);
proto_item *iu = proto_tree_add_text(tu,tvb,offset,4,"Unknown Vendor, "
"if you know whose this is you can add it to dictionary.xml");
expert_add_info_format(c->pinfo, iu, PI_UNDECODED, PI_WARN, "Unknown Vendor");
PROTO_ITEM_SET_GENERATED(iu);
pi = proto_tree_add_text(tu,tvb,offset,4,"Unknown Vendor, "
"if you know whose this is you can add it to dictionary.xml");
expert_add_info_format(c->pinfo, pi, PI_UNDECODED, PI_WARN, "Unknown Vendor");
PROTO_ITEM_SET_GENERATED(pi);
}
offset += 4;
}
if ( len == (guint32)(vendor_flag ? 12 : 8) ) {
/* Data is empty so return now */
proto_item *iu = proto_tree_add_text(avp_tree,tvb,offset,0,"No data");
expert_add_info_format(c->pinfo, iu, PI_UNDECODED, PI_WARN, "Data is empty");
PROTO_ITEM_SET_GENERATED(iu);
return len;
pi = proto_tree_add_text(avp_tree,tvb,offset,0,"No data");
expert_add_info_format(c->pinfo, pi, PI_UNDECODED, PI_WARN, "Data is empty");
PROTO_ITEM_SET_GENERATED(pi);
/* pad_len is always 0 in this case, but kept here for consistency */
return len+pad_len;
}
subtvb = tvb_new_subset(tvb,offset,len-(8+(vendor_flag?4:0)),len-(8+(vendor_flag?4:0)));
offset += len-(8+(vendor_flag?4:0));
save_tree = c->tree;
c->tree = avp_tree;
@ -524,7 +530,19 @@ dissect_diameter_avp(diam_ctx_t *c, tvbuff_t *tvb, int offset)
proto_tree_add_text(avp_tree, subtvb, 0, -1, "AVP %u data, Vendor Id %u ",code,vendorid);
*/
return len;
if (pad_len) {
guint8 i;
pi = proto_tree_add_item(avp_tree, hf_diameter_avp_pad, tvb, offset, pad_len, ENC_NA);
for (i=0; i < pad_len; i++) {
if (tvb_get_guint8(tvb, offset++) != 0) {
expert_add_info_format(c->pinfo, pi, PI_MALFORMED, PI_NOTE, "Padding is non-zero");
break;
}
}
}
return len+pad_len;
}
static const char *
@ -819,7 +837,6 @@ grouped_avp(diam_ctx_t *c, diam_avp_t *a, tvbuff_t *tvb)
while (offset < len) {
offset += dissect_diameter_avp(c, tvb, offset);
offset += (offset % 4) ? 4 - (offset % 4) : 0 ;
}
c->tree = pt;
@ -1068,12 +1085,8 @@ dissect_diameter_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
/* Dissect AVPs until the end of the packet is reached */
while (offset < packet_len) {
offset += dissect_diameter_avp(c, tvb, offset);
/* Skip to next 4-byte boundary */
offset += (offset % 4) ? 4 - (offset % 4) : 0 ;
}
/* Handle requests for which no answers were found and
* anawers for which no requests were found in the tap listener.
* In case if you don't need unpaired requests/answers use:
@ -1715,6 +1728,8 @@ real_proto_register_diameter(void)
{ &hf_diameter_avp_len,
{ "AVP Length","diameter.avp.len", FT_UINT24, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_diameter_avp_code,
{ "AVP Code", "diameter.avp.code", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL }},
{ &hf_diameter_avp_flags,
{ "AVP Flags","diameter.avp.flags", FT_UINT8, BASE_HEX,
NULL, 0x0, NULL, HFILL }},
@ -1746,15 +1761,13 @@ real_proto_register_diameter(void)
{ "AVP Vendor Id","diameter.avp.vendorId", FT_UINT32, BASE_DEC|BASE_EXT_STRING,
&sminmpec_values_ext, 0x0, NULL, HFILL }},
{ &(unknown_avp.hf_value),
{ "Value","diameter.avp.unknown", FT_BYTES, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ "Value","diameter.avp.unknown", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
{ &hf_diameter_avp_data_wrong_length,
{ "Data","diameter.avp.invalid-data", FT_BYTES, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ "Data","diameter.avp.invalid-data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
{ &hf_diameter_avp_pad,
{ "Padding","diameter.avp.pad", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
{ &hf_diameter_code,
{ "Command Code", "diameter.cmd.code", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL }},
{ &hf_diameter_avp_code,
{ "AVP Code", "diameter.avp.code", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL }},
{ &hf_diameter_answer_in,
{ "Answer In", "diameter.answer_in", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
"The answer to this diameter request is in this frame", HFILL }},
@ -1766,20 +1779,16 @@ real_proto_register_diameter(void)
"The time between the request and the answer", HFILL }},
{ &hf_framed_ipv6_prefix_reserved,
{ "Framed IPv6 Prefix Reserved byte", "diameter.framed_ipv6_prefix_reserved",
FT_UINT8, BASE_HEX, NULL, 0,
NULL, HFILL }},
FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL }},
{ &hf_framed_ipv6_prefix_length,
{ "Framed IPv6 Prefix length (in bits)", "diameter.framed_ipv6_prefix_length",
FT_UINT8, BASE_DEC, NULL, 0,
NULL, HFILL }},
FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL }},
{ &hf_framed_ipv6_prefix_bytes,
{ "Framed IPv6 Prefix as a bytestring", "diameter.framed_ipv6_prefix_bytes",
FT_BYTES, BASE_NONE, NULL, 0,
NULL, HFILL }},
FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL }},
{ &hf_framed_ipv6_prefix_ipv6,
{ "Framed IPv6 Prefix as an IPv6 address", "diameter.framed_ipv6_prefix_ipv6",
FT_IPv6, BASE_NONE, NULL, 0,
"This field is present only if the prefix length is 128", HFILL }}
FT_IPv6, BASE_NONE, NULL, 0, "This field is present only if the prefix length is 128", HFILL }}
};
gint *ett_base[] = {