Re: [PATCH] X.509: if signature is unsupported skip validation

[Thore Sommer]

On 16.08.23 23:54, Jarkko Sakkinen wrote:
> On Tue Aug 15, 2023 at 2:29 PM EEST, Thore Sommer wrote:
> > When the hash algorithm for the signature is not available the digest size
> > is 0 and the signature in the certificate is marked as unsupported.
> >
> > When validating a self-signed certificate, this needs to be checked,
> > because otherwise trying to validate the signature will fail with an
> > warning:
> >
> > Loading compiled-in X.509 certificates
> > WARNING: CPU: 0 PID: 1 at crypto/rsa-pkcs1pad.c:537 \
> > pkcs1pad_verify+0x46/0x12c
> > ...
> > Problem loading in-kernel X.509 certificate (-22)
> >
> > Signed-off-by: Thore Sommer <public@xxxxxxxx>
> > ---
> >   crypto/asymmetric_keys/x509_public_key.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
> > index 6fdfc82e23a8..7c71db3ac23d 100644
> > --- a/crypto/asymmetric_keys/x509_public_key.c
> > +++ b/crypto/asymmetric_keys/x509_public_key.c
> > @@ -130,6 +130,11 @@ int x509_check_for_self_signed(struct x509_certificate *cert)
> >   			goto out;
> >   	}
> >   
> > +	if (cert->unsupported_sig) {
> > +		ret = 0;
> > +		goto out;
> > +	}
> > +
> >   	ret = public_key_verify_signature(cert->pub, cert->sig);
> >   	if (ret < 0) {
> >   		if (ret == -ENOPKG) {
> > --
> > 2.41.0
>
> Should have:
>
> Cc: stable@xxxxxxxxxxxxxxx # v4.7+
> Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
>
> BR, Jarkko

Hi Jarkko,

should I resend it with the stable mailing list in CC or will it be 
added when a maintainer includes the change?

Best regards,
Thore