Ethereal-dev: [Ethereal-dev] [patch, capture] SRVLOC dissector - fixup for naming authority

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From: Brad Hards <bhards@xxxxxxxxxxxxxx>
Date: Thu, 23 Jan 2003 20:47:51 +1100
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Tim Jansen reported a bug to me concerning the SRVLOC dissector. The problem
is when you have a SrvTypeRqst for all naming authorities.

RFC2608, Section 10.1 states:
"  If the Naming Authority string is absent, the IANA
   registered service types will be returned.  If the length of the
   Naming Authority is set to 0xFFFF, the Naming Authority string is
   omitted and ALL Service Types are returned, regardless of Naming
   Authority."

That chokes the current dissector, which uses the length to read the
subsequent 65535 bytes, only to come up short. There is a sample capture that
shows this.

I have no idea how I missed this case when I did my original testing - I
certainly have a SrvTypeRqst test case, but it has a length of 0 (ie, the
IANA case), not 65535 (the all authorities case).

The only way I can see to fix this up is to special case this. Please review
the attached patch, and apply if OK.

MD5 sum patch of patch:
a03fc3572daa142a8c3ce7bb60efbaa1  srvloc-ffff-fix.patch

Brad

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Attachment: no-authority.cap
Description: Binary data

diff -Naur -x register.c -x register-static.c -x ps.c clean/ethereal-0.9.8/packet-srvloc.c ethereal-0.9.8/packet-srvloc.c
--- clean/ethereal-0.9.8/packet-srvloc.c	Sat Oct  5 13:47:38 2002
+++ ethereal-0.9.8/packet-srvloc.c	Thu Jan 23 18:12:33 2003
@@ -109,6 +109,7 @@
 static int hf_srvloc_srvtypereq_prlistlen = -1;
 static int hf_srvloc_srvtypereq_prlist = -1;
 static int hf_srvloc_srvtypereq_authlistlen = -1;
+static int hf_srvloc_srvtypereq_authlistlenall = -1;
 static int hf_srvloc_srvtypereq_authlist = -1;
 static int hf_srvloc_srvtypereq_scopelistlen = -1;
 static int hf_srvloc_srvtypereq_scopelist = -1;
@@ -884,10 +885,15 @@
                 proto_tree_add_item(srvloc_tree, hf_srvloc_srvtypereq_prlist, tvb, offset, length, TRUE);
                 offset += length;
                 length = tvb_get_ntohs(tvb, offset);
-                proto_tree_add_uint(srvloc_tree, hf_srvloc_srvtypereq_authlistlen, tvb, offset, 2, length);
-                offset += 2;
-                proto_tree_add_item(srvloc_tree, hf_srvloc_srvtypereq_authlist, tvb, offset, length, TRUE);
-                offset += length;
+		if (0xFFFF == length) {
+		    proto_tree_add_uint(srvloc_tree, hf_srvloc_srvtypereq_authlistlenall, tvb, offset, 2, length);
+		    offset += 2;
+		} else {
+		    proto_tree_add_uint(srvloc_tree, hf_srvloc_srvtypereq_authlistlen, tvb, offset, 2, length);
+		    offset += 2;
+		    proto_tree_add_item(srvloc_tree, hf_srvloc_srvtypereq_authlist, tvb, offset, length, TRUE);
+		    offset += length;
+		}
                 length = tvb_get_ntohs(tvb, offset);
                 proto_tree_add_uint(srvloc_tree, hf_srvloc_srvtypereq_scopelistlen, tvb, offset, 2, length);
                 offset += 2;
@@ -1270,6 +1276,10 @@
 	  { "Naming Authority List Length", "srvloc.srvtypereq.nameauthlistlen", FT_UINT16, BASE_DEC, NULL, 0x0,
 	    "Length of the Naming Authority List", HFILL}
 	},
+	{ &hf_srvloc_srvtypereq_authlistlenall,
+	  { "Naming Authority List Length (All Naming Authorities)", "srvloc.srvtypereq.nameauthlistlen", FT_UINT16, BASE_DEC, NULL, 0x0,
+	    "Length of the Naming Authority List", HFILL}
+	},
 	{ &hf_srvloc_srvtypereq_authlist,
 	  { "Naming Authority List", "srvloc.srvtypereq.nameauthlist", FT_STRING, BASE_DEC, NULL, 0x0,
 	    "", HFILL}