Fwd: [gnutls-devel] Symbol versioning in gnutls broken -> crashes

[Dagobert Michelsen]

Hi folks,

Looks like other distros suffer the same pain /-)

Best regards -- Dago


Anfang der weitergeleiteten E‑Mail:

> Von: Andreas Metzler <ametzler at bebt.de>
> Datum: 24. Mai 2014 08:58:07 MESZ
> An: gnutls-devel at lists.gnutls.org
> Betreff: [gnutls-devel] Symbol versioning in gnutls broken -> crashes
> 
> Hello,
> 
> GnuTLS symbol versioning apparently does not fullfill its main
> purpose, to allow a binary to link against gnutls 2.x and gnutls 3.x
> without crashing.
> 
> This is a pretty common screnario for distributions in a transition
> period, where you go from:
> 
> scenario1
> application --depends_on--> libgnutls.so.26
>            `-depends_on--> libbar.so.5 --dep_on--> libgnutls.so.26
> 
> to
> 
> scenario2
> application --depends_on--> libgnutls.so.26
>            `-depends_on--> libbar.so.5 --dep_on--> libgnutls.so.28
> 
> at some point of time, since you cannot switch the whole distro at one
> point. Especially for the GnuTLS transition, since this is not just a
> straight rebuild but involves checking the source's gcrypt related
> code.
> 
> Usually symbol-versioning would cause any references to gnutls to be
> resolved to GnuTLS 2.x in both of the abovementioned cases, libbar's
> to GnuTLS 2.x or 3.x respectively. However e.g. gnutls_init() is
> versioned as @1.4 in both gnutls versions, therefore in scenario2
> application could also get gnutls_init() from GnuTLS 3.x.
> 
> Another function where it is obvious this breaks is
> gnutls_priority_set_direct(), where 3.x accepts more priority strings.
> 
> ------
> 
> Anyway, this causes hard crashes like in
> <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=746641#37> or
> <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=748742#37>.
> 
> Fixing this in gnutls' source is pretty easy: In gnutls.map move the
> contents of GNUTLS_1_4, GNUTLS_2_8, GNUTLS_2_10 and GNUTLS_2_12 to
> GNUTLS_3_0_0. However it breaks the ABI, everything linking against
> gnutls3 will need to be rebuilt after the change. Afaiu a soname bump
> would therefore be the correct thing.
> 
> cu Andreas
> 
> See also:
> <https://lists.debian.org/debian-release/2014/05/msg00262.html>
> 
> -- 
> `What a good friend you are to him, Dr. Maturin. His other friends are
> so grateful to you.'
> `I sew his ears on from time to time, sure'
> 
> _______________________________________________
> Gnutls-devel mailing list
> Gnutls-devel at lists.gnutls.org
> http://lists.gnupg.org/mailman/listinfo/gnutls-devel
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