Re: [PATCH v5] crypto: af_alg - add extra parameters for DRBG interface

Eric Biggers [off-list ref] wrote:

Since proto_ops are almost identical, and only one is used in a given kernel
build, why not just do:

static struct proto_ops algif_rng_ops = {
       ...
#ifdef CONFIG_CRYPTO_USER_API_RNG_CAVP
       .sendmsg        = rng_sendmsg,
#else
       .sendmsg        = sock_no_sendmsg,
#endif
       ...
};

Similarly for .recvmsg(), although I don't understand what's wrong with just
adding the lock_sock() instead...  The RNG algorithms do locking anyway, so it's
not like that would regress the ability to recvmsg() in parallel.  Also,
conditional locking depending on the kernel config makes it more difficult to
find kernel bugs like deadlocks.

I want this to have minimal impact on anyone who's not using it.
After all, this is something that only Google is asking for.

Anyway, I wasn't looking for a compile-time ops switch, but a
run-time one.

I think what we can do is move the new newsock->ops assignment
in af_alg_accept up above the type->accept call which would then
allow it to be overridden by the accept call.

After that you could just change newsock->ops depending on whether
pctx->entropy is NULL or not in rng_accept_parent.

As for the proto_ops duplication I don't think it's that big a
deal, but if you're really bothered just create a macro for the
identical bits in the struct.

Thanks,
-- 
Email: Herbert Xu [off-list ref]
Home Page: http://gondor.apana.org.au/~herbert/
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