Tuesday, 12 October 2021

More fun with keyctl on Ubuntu

Following on from my earlier post: -

Fun with keyctl on Ubuntu

I started seeing the same Bad message exception when adding a certificate into a keyring: -

keyctl padd asymmetric foo @u < ~/ssl/server.crt 

add_key: Bad message

even though the required kernel module was loaded: -

lsmod |grep pkcs

pkcs8_key_parser       16384  0

and this appeared to be a valid certificate: -

file ~/ssl/server.crt

/home/hayd/ssl/server.crt: PEM certificate

openssl verify -verbose -CAfile ~/ssl/etcd-ca.crt ~/ssl/server.crt

/home/hayd/ssl/server.crt: OK

so, as per the above, the certificate is stored in Privacy Enhanced Mail (PEM) format: -

PEM or Privacy Enhanced Mail is a Base64 encoded DER certificate. PEM certificates are frequently used for web servers as they can easily be translated into readable data using a simple text editor. Generally when a PEM encoded file is opened in a text editor, it contains very distinct headers and footers.

Jumping to a conclusion that keyctl may require a different format e.g. Distinguished Encoding Rules (DER) instead: -

DER (Distinguished Encoding Rules) is a binary encoding for X.509 certificates and private keys. Unlike PEM, DER-encoded files do not contain plain text statements such as -----BEGIN CERTIFICATE-----. DER files are most commonly seen in Java contexts.

I regenerated the certificate: -

openssl x509 -req -extfile <(printf "subjectAltName=DNS:localhost,DNS:genctl-etcd-cluster.genctl.svc,DNS:genctl-etcd-cluster-client.genctl.svc") -days 365 -in ~/ssl/server.csr -CA ~/ssl/etcd-ca.crt -CAkey ~/ssl/etcd-ca.key -CAcreateserial -out ~/ssl/server.der -outform der

in DER format ( via -outform der ) and verified it: -

file ~/ssl/server.der

/home/hayd/ssl/server.der: data

and then imported it using keyctl : -

export description="Test1"

keyctl padd asymmetric $description @u < ~/ssl/server.der


and validated thusly: -

keyctl list @u

1 key in keyring:
526852507: --als--v  1000  1000 asymmetric: Test1


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