Wireshark-bugs: [Wireshark-bugs] [Bug 6246] New: Incorrect PER UNALIGNED decoding of IA5String
Date Index · Thread Index · Other Months · All Mailing Lists
Date Prev · Date Next · Thread Prev · Thread Next
From: bugzilla-daemon@xxxxxxxxxxxxx
Date: Wed, 17 Aug 2011 03:59:02 -0700 (PDT)
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6246

           Summary: Incorrect PER UNALIGNED decoding of IA5String
           Product: Wireshark
           Version: 1.6.1
          Platform: x86
        OS/Version: Windows 7
            Status: NEW
          Severity: Major
          Priority: Low
         Component: Wireshark
        AssignedTo: bugzilla-admin@xxxxxxxxxxxxx
        ReportedBy: jleskovar@xxxxxxxxx


Created an attachment (id=6839)
 --> (https://bugs.wireshark.org/bugzilla/attachment.cgi?id=6839)
Incorrect decoding of IA5String as 8-bit ascii characters

Build Information:
Version 1.6.1 (SVN Rev 38096 from /trunk-1.6)

Copyright 1998-2011 Gerald Combs <gerald@xxxxxxxxxxxxx> and contributors.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Compiled (32-bit) with GTK+ 2.22.1, with GLib 2.26.1, with WinPcap (version
unknown), with libz 1.2.5, without POSIX capabilities, without libpcre, with
SMI
0.4.8, with c-ares 1.7.1, with Lua 5.1, without Python, with GnuTLS 2.10.3,
with
Gcrypt 1.4.6, with MIT Kerberos, with GeoIP, with PortAudio V19-devel (built
Jul
18 2011), with AirPcap.

Running on 32-bit Windows 7, build 7600, with WinPcap version 4.1.2 (packet.dll
version 4.1.0.2001), based on libpcap version 1.0 branch 1_0_rel0b (20091008),
GnuTLS 2.10.3, Gcrypt 1.4.6, without AirPcap.

Built using Microsoft Visual C++ 9.0 build 21022

Wireshark is Open Source Software released under the GNU General Public
License.

Check the man page and http://www.wireshark.org for more information.
--
Wireshark appears to be incorrectly decoding IA5String fields in PER UNALIGNED
encoded messages. The attached pcap file is of a ULP PDU - SUPL Start
(http://member.openmobilealliance.org/ftp/Public_documents/LOC/Permanent_documents/OMA-TS-ULP-V2_0-20110523-D.zip). 

Of interest is the "nai" choice in sessionID.setSessionID.setId. The value of
this field is the IA5String "1234". Wireshark appears to be decoding the string
as 8-bit ascii, whereas the characters are encoded as 7-bit ascii. X.691-0207
(http://www.itu.int/ITU-T/studygroups/com17/languages/X.691-0207.pdf) gives
clear guidance on how the unaligned variant of IA5String should be encoded,
mainly in Chapter 27, Note 3. It suggests that the correct encoding of each
character should indeed consume 7 bits (ie. smallest number of bits that can
encode N-1, N=128 characters for IA5String)

-- 
Configure bugmail: https://bugs.wireshark.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are watching all bug changes.