Re: [PATCH v2] crypto: sa2ul - Fix stack overflow in sa_prepare_iopads

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

On Mon, Aug 31, 2026 at 11:21:38AM +0530, Siddharth Vadapalli wrote:
>
> Since crypto_shash_export() writes 105 bytes into this 104-byte union, it
> overflows by one byte into the adjacent stack frame.

This should be converted to crypto_shash_export_core which exports
just the hash state without the partial block buffer.
 
> Changes since v1:
> - Propagated error from sa_prepare_iopads throughout the call chain.
> - Added missing check for authentication key size being within limits.
> Above changes are based on Sashiko review of the v1 patch at:
> https://sashiko.dev/#/patchset/20260819142357.3950463-1-s-vadapalli%40ti.com

Looks like Sashiko is still not happy:

https://sashiko.dev/#/patchset/20260831055141.1632832-1-s-vadapalli%40ti.com

Let's split this up.  Just do a one-liner to switch shash_export
to shash_export_core, that should fix the stack overrun.  Then
fix the long key issue in a separate patch.

I think you should support long keys properly by hashing them as
crypto/hmac.c does.

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