Messages in this thread | | | Date | Fri, 28 Sep 2007 14:20:15 -0700 (PDT) | Subject | Re: PATCH: tcp rfc 2385 security/bugfix for sparc64 | From | David Miller <> |
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From: "Peter Lieven" <pl@dlh.net> Date: Fri, 28 Sep 2007 22:42:25 +0200 (CEST)
> TCP MD5 signatures on sparc64 (big-endian) completely fail on current > kernel releases in interoperability with Cisco/Foundry or other > little-endian linux systems. > > The root cause is a cast in the return statement of tcp_v4_md5_do_lookup, > where a tcp4_md5sig_key is casted onto tcp_md5sig_key without proper > conversion. On little-endian systems the upper 8 bits are cut of which > yields the expected behaviour. However, on big-endian systems (like > sparc64) only the most significant 8 bits are preserved. Since > TCP_MD5SIG_MAXKEYLEN is 80, this always yields 0. > > In the calculation of the md5 signature afterwards the key is therefore > not appended to the tcp segment which could result in a security problem > since only the presence of a md5 signature is checked, and the key itself > doesn't matter.
Thanks for finding this bug.
> --- linux.old/include/net/tcp.h 2007-09-28 21:43:26.000000000 +0200 +++ > linux/include/net/tcp.h 2007-09-28 21:45:35.000000000 +0200 @@ -1055,6 > +1055,7 @@ static inline void clear_all_retrans_hin
I'll have to apply this patch by hand because your email client completely corrupted the patch.
> Signed-off-by: Peter Lieven <pl@dlh.net> > Signed-off-by: Matthias M. Dellweg <2500@gmx.de>
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