Quality for binary distributions

[Niels Möller]

Here's a common scenario where make check may fail to detect problems.
Say a distributor compiles gmp, runs make check, and builds some type of
binary package, which is distributed to users. For supported platforms
(i.e., x86), fat builds are typically used. Now, the user has a
different cpu flavour, so may exersize different code than make check on
the machine where gmp was built.

As far as I understand, it would typically affect only assembly code
(which is supposedly well tested and not subject to compiler bugs). But
if the fat machinery selects between assembly and C implementation (does
it ever do that?), the user could also see compiler bugs not visible on
the build machine.

Can we do anything about this? Like, distribute some gmp checking tools
to end users?

What got me thinking about this was a gnutls bug report about occasional
problems with bad rsa signatures (which could be a bug in gnutls,
nettle, gmp, or the hardware). It would be good to be able to check if
the problem is below or above gmp. See
http://lists.gnutls.org/pipermail/gnutls-help/2015-June/003889.html

On the nettle side, I ought to add code to check validy of all generated
signatures before passing them on, since an error in the computation may
leak the secret key.

Regards,
/Niels


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