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

[Siddharth Vadapalli]

On 9/16/26 2:30 PM, Herbert Xu wrote:
> 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.

Thank you for reviewing the patch and providing your valuable feedback.

I will split the patch as you have suggested with the one-line fix patch 
posted first followed by an independent patch posted later for handling 
long keys.

Regards,
Siddharth.