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Buffer length checking errors in CODA

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                 NetBSD Security Advisory 2010-006

Topic:          Buffer length checking errors in CODA

Version:        NetBSD-current:         affected prior to July 20, 2010
                NetBSD 5.0.2:           affected
                NetBSD 5.0.1:           affected
                NetBSD 5.0:             affected
                NetBSD 4.0.1:           affected
                NetBSD 4.0:             affected

Severity:       Local Kernel Memory Information Disclosure

Fixed:          NetBSD-current:         Jul 20, 2010
                NetBSD-5 branch         Aug 26, 2010
                NetBSD-5-0 branch       Aug 26, 2010
                NetBSD-4 branch         Aug 4, 2010
                NetBSD-4-0 branch       Aug 4, 2010

Please note that NetBSD releases prior to 4.0 are no longer supported.
It is recommended that all users upgrade to a supported release.


The CODA filesystem kernel module was incorrectly checking buffer
limits enabling a regular user read access to kernel memory.

Technical Details

The type of the size parameters in the vice ioctl was signed short,
and by using negative values, the size checks where sometimes bypassed.

Solutions and Workarounds

- - Don't mount coda volumes.
- - Recompile and re-install the kernel.

  CVS branch    file                                    revision
  ------------- ----------------                        -----------
  HEAD          src/sys/coda/coda.h                     1.16
  HEAD          src/sys/coda/coda_venus.c               1.28
  HEAD          src/sys/coda/coda_vnops.c               1.76

  netbsd-4      src/sys/coda/coda.h           
  netbsd-4      src/sys/coda/coda_venus.c     
  netbsd-4      src/sys/coda/coda_vnops.c     

  netbsd-4-0    src/sys/coda/coda.h           
  netbsd-4-0    src/sys/coda/coda_venus.c     
  netbsd-4-0    src/sys/coda/coda_vnops.c     

  netbsd-5      src/sys/coda/coda.h           
  netbsd-5      src/sys/coda/coda_venus.c     
  netbsd-5      src/sys/coda/coda_vnops.c     

  netbsd-5-0    src/sys/coda/coda.h           
  netbsd-5-0    src/sys/coda/coda_venus.c     
  netbsd-5-0    src/sys/coda/coda_vnops.c     

The fixed source may be obtained from the NetBSD CVS repository.
The following instructions briefly summarise how to upgrade your
kernel.  In these instructions, replace:

  ARCH     with your architecture (from uname -m), and
  BRANCH   with the appropriate CVS branch (from the above table)
  FILES    with the file names for that branch (from the above table)
  KERNCONF with the name of your kernel configuration file.

To update from CVS, re-build, and re-install the kernel:

        # cd src
        # cvs update -d -P -r BRANCH FILES
        # ./ tools kernel=KERNCONF
        # mv /netbsd /netbsd.old
        # cp sys/arch/ARCH/compile/obj/KERNCONF/netbsd /netbsd
        # shutdown -r now

For more information on how to do this, see:

Thanks To

Dan J. Rosenberg for discovering and notifying us about the bug,
and Christos Zoulas for fixing the problem.

Revision History

        2010-08-25      Initial release

More Information

Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at

Information about NetBSD and NetBSD security can be found at and

Copyright 2010, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2010-006.txt,v 1.2 2010/08/25 21:54:36 tonnerre Exp $

Version: GnuPG v1.4.10 (NetBSD)


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