Re: [PATCH] crypto: caam - Fix DMA corruption on long hmac keys

[Herbert Xu <herbert@gondor.apana.org.au>]

On Tue, Mar 10, 2026 at 05:12:10PM +0200, Horia Geantă wrote:
> 
> When aligned_len is bigger than keylen, kmemdup would go beyond the end of
> "key" buffer.
> 
> Looks like kzalloc + memcpy should be used instead of kmemdup.
> 
> Double checking the faulty commit, I've found the same pattern in
> ahash_setkey from drivers/crypto/caam/caamalg_qi2.c. Let me know if you'd
> send a fix for this or I should do it.

Hi Horia:

While we should still fix this, it turns out that the original
problem went beyond the memory allocation.

The root cause of the self-test failure is actually caused by
the parallel self-test mechanism which became the default in
2024.

It appears the caam is unable to deal with this because the
ahash_setkey function will fail if caam_jr_enqueue returns
ENOSPC, which is bound to happen sooner or later in a parallel
environment.

So it'll either need to deal with ENOSPC, or switch to a
software fallback.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt