Re: short read from /dev/urandom

[Ulrich Drepper]

Theodore Ts'o wrote:
> What do you think?  Does gcc -pg calls sigaction with SA_RESTART, to
> avoid changing the behaviour of the programs that it is profiling?

Profiling certainly uses SA_RESTART.  But this was just one possible 
problem case.

I'm concerned that there is isgnificant code out there relying on the 
no-short-read promise.  And perhaps more importantly, other 
implementations promise the same.

The code in question comes from a crypto library which is in wide use 
(http://www.cryptopp.com) and it is using urandom under this assumption. 
 I fear there is quite a bit more code like this out there.  Changing 
the ABI after the fact is no good and dangerous in this case.

I know this is making the device special, but I really think the 
no-short-reads property should be perserved for urandom.

--
â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, CA â

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