[PATCH v2 v2] evm: check return values of crypto_shash functions

[Roberto Sassu]

On 3/9/2026 4:03 PM, Mimi Zohar wrote:
> On Thu, 2026-02-19 at 10:26 +0100, Roberto Sassu wrote:
>> On Thu, 2026-02-05 at 21:42 -0500, Daniel Hodges wrote:
>>> The crypto_shash_update() and crypto_shash_final() functions can fail
>>> and return error codes, but their return values were not being checked
>>> in several places in security/integrity/evm/evm_crypto.c:
>>>
>>> - hmac_add_misc() ignored returns from crypto_shash_update() and
>>>    crypto_shash_final()
>>> - evm_calc_hmac_or_hash() ignored returns from crypto_shash_update()
>>> - evm_init_hmac() ignored returns from crypto_shash_update()
>>>
>>> If these hash operations fail silently, the resulting HMAC could be
>>> invalid or incomplete, which could weaken the integrity verification
>>> security that EVM provides.
>>>
>>> This patch converts hmac_add_misc() from void to int return type and
>>> adds proper error checking and propagation for all crypto_shash_*
>>> function calls. All callers are updated to handle the new return values.
>>> Additionally, error messages are logged when cryptographic operations
>>> fail to provide visibility into the failure rather than silently
>>> returning error codes.
>>>
>>> Fixes: 66dbc325afce ("evm: re-release")
>>> Signed-off-by: Daniel Hodges <git at danielhodges.dev>
>>
>> After fixing the minor issue below:
>>
>> Reviewed-by: Roberto Sassu <roberto.sassu at huawei.com>
> 
> Thanks Daniel, Roberto.  Daniel there are a couple of places where the line
> length is greater than 80.  To see them, add "--max-line-length=80" to
> scripts/checkpatch.pl.  I'd appreciate your fixing them.  Otherwise, the patch
> looks good.

Daniel, do you have time to fix the style issues, so that we upstream 
your patch?

Thanks

Roberto