Re: [PATCH] KEYS: Fix signature input size for KEYCTL_PKEY_VERIFY

[Stefan Berger <stefanb@linux.ibm.com>]

On 11/13/26 9:11 AM, Jarkko Sakkinen wrote:
> On Fri, Nov 13, 2026 at 04:10:12PM +0200, Jarkko Sakkinen wrote:
>> On Fri, Nov 13, 2026 at 09:03:11AM -0500, Stefan Berger wrote:
>>> Revert the changes made for signature verification in cb481e59ea6c back
>>> to the old behavior where effectively the params->in2_len was set to the
>>> length of the user provided buffer uparams.in2_len (out_len is an alias
>>> for in2_len due to the union). We cannot use the max_sig_size in the
>>> case of signature verification since this is neither the true size of the
>>> input buffer nor would it pass tests of size indicators found in the ASN.1
>>> in the buffer comparing against the input buffer size.
>>>
>>> Fixes: cb481e59ea6c ("KEYS: fix overflow in keyctl_pkey_params_get_2()")
>>> Cc: Jarkko Sakkinen <jarkko@kernel.org>
>>> Cc: Florian Bauckholt <florian.bauckholt@cispa.de>
>>> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
>>> ---
>>>   security/keys/keyctl_pkey.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/security/keys/keyctl_pkey.c b/security/keys/keyctl_pkey.c
>>> index 15b6bf6399b5..794fa3d01911 100644
>>> --- a/security/keys/keyctl_pkey.c
>>> +++ b/security/keys/keyctl_pkey.c
>>> @@ -160,7 +160,7 @@ static int keyctl_pkey_params_get_2(const struct keyctl_pkey_params __user *_par
>>>   		    uparams.in2_len > info.max_sig_size)
>>>   			return -EINVAL;
>>>   
>>> -		params->out_len = info.max_sig_size;
>>> +		params->in2_len = uparams.in2_len;
>>>   		break;
>>>   	default:
>>>   		return -EOPNOTSUPP;
>>> -- 
>>> 2.56.0
>>>
>>
>>
>> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> 
> Did we have reported-by and closes tags for this?

Let me add this here for v2:

Link: 
https://lore.kernel.org/linux-crypto/473700a3-f5d7-4a7a-b89a-12c51adcc3df@cispa.de/T/#t
Reported-by: Sashiko <sashiko-bot@kernel.org>

Once Florian added his Tested-by: to v1 should I then add this?

Cc: stable@vger.kernel.org

> 
> Br, Jarkko