On Thu, Apr 16, 2015 at 05:13:50PM +0200, Stephan Mueller wrote: > > Surely, the shadow approach scales better than a global lock. But its > drawback > is the (almost) identical state.
The drawback is that your DRBG is no longer anything like that specified by the standard. You've completely changed the cryptography by reusing the internal state. > Rafael: do you have any better idea here other than remove the shadow copy > approach and use a global lock? I don't think you can get around the global lock due to the sequential nature of the DRBG that is built into its design. > >The only users of RNG in the crypto API do so in process context > >so we can make it a rule that all users RNG must be in process > >context. > > Herbert, which type of lock am I allowed to use? Is a spin lock sufficient or > shall I use a mutex. I am not fully sure whether the used shash or cipher > type > can sleep. As I said we can make it a rule that any user of our RNG must be in process context (all existing users are) so you can use a mutex. Also, if we change the entropy source to a blocking one as discussed in the other thread then you'd definitely want to have a mutex intead of a spin lock. Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
