[FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-14:11.crypt

Fri Oct 24 11:14:32 UTC 2014

Hi,

I was wondering if there is more information about this change?  FreeBSD changed the default away from DES to MD5 back in the 1.1.5 -> 2.0 transition.  It seems to me a downgrade and rewarding bad programming to be changing back to DES now.  Also the proper course of action is to correct programs that make the wrong assumption about what crypt() changes.

Thanks

- JimP

On Oct 22, 2014, at 4:07 PM, FreeBSD Errata Notices <errata-notices at freebsd.org> wrote:

> Signed PGP part
> =============================================================================
> FreeBSD-EN-14:11.crypt                                          Errata Notice
>                                                           The FreeBSD Project
> 
> Topic:          crypt(3) default hashing algorithm
> 
> Category:       core
> Module:         libcrypt
> Announced:      2014-10-22
> Affects:        FreeBSD 9.3 and FreeBSD 10.0-STABLE after 2014-05-11 and
>                 before 2014-10-16.
> Corrected:      2014-10-13 15:56:47 UTC (stable/10, 10.1-PRERELEASE)
>                 2014-10-16 21:39:04 UTC (releng/10.1, 10.1-RC3)
>                 2014-10-16 21:39:04 UTC (releng/10.1, 10.1-RC2-p2)
>                 2014-10-16 21:39:04 UTC (releng/10.1, 10.1-RC1-p2)
>                 2014-10-16 21:39:04 UTC (releng/10.1, 10.1-BETA3-p2)
>                 2014-10-21 21:09:54 UTC (stable/9, 9.3-STABLE)
>                 2014-10-21 23:50:46 UTC (releng/9.3, 9.3-RELEASE-p4)
> 
> For general information regarding FreeBSD Errata Notices and Security
> Advisories, including descriptions of the fields above, security
> branches, and the following sections, please visit
> <URL:http://security.freebsd.org/>.
> 
> I.   Background
> 
> The crypt(3) function performs password hashing.  Different algorithms
> of varying strength are available, with older, weaker algorithms being
> retained for compatibility.
> 
> The crypt(3) function was originally based on the DES encryption
> algorithm and generated a 13-character hash from an eight-character
> password (longer passwords were truncated) and a two-character salt.
> 
> II.  Problem Description
> 
> In recent FreeBSD releases, the default algorithm for crypt(3) was
> changed to SHA-512, which generates a much longer hash than the
> traditional DES-based algorithm.
> 
> III. Impact
> 
> Many applications assume that crypt(3) always returns a traditional DES
> hash, and blindly copy it into a short buffer without bounds checks. This
> may lead to a variety of undesirable results including, at worst, crashing
> the application.
> 
> IV.  Workaround
> 
> No workaround is available.
> 
> V.   Solution
> 
> Perform one of the following:
> 
> 1) Upgrade your system to a supported FreeBSD stable or release / security
> branch (releng) dated after the correction date.
> 
> 2) To update your present system via a source code patch:
> 
> The following patches have been verified to apply to the applicable
> FreeBSD release branches.
> 
> a) Download the relevant patch from the location below, and verify the
> detached PGP signature using your PGP utility.
> 
> # fetch http://security.FreeBSD.org/patches/EN-14:11/crypt.patch
> # fetch http://security.FreeBSD.org/patches/EN-14:11/crypt.patch.asc
> # gpg --verify crypt.patch.asc
> 
> b) Apply the patch.  Execute the following commands as root:
> 
> # cd /usr/src
> # patch < /path/to/patch
> 
> c) Recompile the operating system using buildworld and installworld as
> described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>.
> 
> Restart all deamons using the library, or reboot the system.
> 
> 3) To update your system via a binary patch:
> 
> Systems running a RELEASE version of FreeBSD on the i386 or amd64
> platforms can be updated via the freebsd-update(8) utility:
> 
> # freebsd-update fetch
> # freebsd-update install
> 
> VI.  Correction details
> 
> The following list contains the revision numbers of each file that was
> corrected in FreeBSD.
> 
> Branch/path                                                      Revision
> -------------------------------------------------------------------------
> stable/9/                                                         r273425
> releng/9.3/                                                       r273438
> stable/10/                                                        r273043
> releng/10.1/                                                      r273187
> -------------------------------------------------------------------------
> 
> To see which files were modified by a particular revision, run the
> following command, replacing NNNNNN with the revision number, on a
> machine with Subversion installed:
> 
> # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
> 
> Or visit the following URL, replacing NNNNNN with the revision number:
> 
> <URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
> 
> VII. References
> 
> The latest revision of this Errata Notice is available at
> http://security.FreeBSD.org/advisories/FreeBSD-EN-14:11.crypt.asc
> 
> _______________________________________________
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--- @(#) $Id: dot.signature,v 1.15 2007/12/27 15:06:13 pirzyk Exp $
    __o  jim at pirzyk.org --------------------------------------------------
 _'\<,_
(*)/ (*) I'd rather be out biking.

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