On Mon, 2022-03-07 at 21:31 -0500, Stefan Berger wrote: > > On 3/7/22 18:38, Eric Snowberg wrote: > > > > > >> On Mar 7, 2022, at 4:01 PM, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > >> > >> On Mon, 2022-03-07 at 18:06 +0000, Eric Snowberg wrote: > >>> > >>>>> diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c > >>>>> index 6b1ac5f5896a..49bb2ea7f609 100644 > >>>>> --- a/crypto/asymmetric_keys/restrict.c > >>>>> +++ b/crypto/asymmetric_keys/restrict.c > >>>>> @@ -108,6 +108,49 @@ int restrict_link_by_signature(struct key *dest_keyring, > >>>>> return ret; > >>>>> } > >>>>> +/** > >>>>> + * restrict_link_by_ca - Restrict additions to a ring of CA keys > >>>>> + * @dest_keyring: Keyring being linked to. > >>>>> + * @type: The type of key being added. > >>>>> + * @payload: The payload of the new key. > >>>>> + * @trust_keyring: Unused. > >>>>> + * > >>>>> + * Check if the new certificate is a CA. If it is a CA, then mark the new > >>>>> + * certificate as being ok to link. > >>>> > >>>> CA = root CA here, right? > >>> > >>> Yes, I’ll update the comment > >> > >> Updating the comment is not enough. There's an existing function named > >> "x509_check_for_self_signed()" which determines whether the certificate > >> is self-signed. > > > > Originally I tried using that function. However when the restrict link code is called, > > all the necessary x509 information is no longer available. The code in > > restrict_link_by_ca is basically doing the equivalent to x509_check_for_self_signed. > > After verifying the cert has the CA flag set, the call to public_key_verify_signature > > validates the cert is self signed. > > > Isn't x509_cert_parse() being called as part of parsing the certificate? > If so, it seems to check for a self-signed certificate every time. You > could add something like the following to x509_check_for_self_signed(cert): > pub->x509_self_signed = cert->self_signed = true; > > This could then reduce the function in 3/4 to something like: > > return payload->data[asym_crypto]->x509_self_signed; Agreed, as long as the other two criteria are also met: CA and keyUsage should be required and limited to keyCertSign. thanks, Mimi
