Support OpenSSH key for ECDSA algorithm

[jamesic]

Is your feature request related to a problem? Please describe.
Could you kindly help support OpenSSH key for ECDSA algorithms?

Describe alternatives you've considered
Currently, I can only use the OpenSSH key for the Ed25519 algorithm.

Additional context
Below is the code I am trying to implement:

        let sshKeyContent = try String(contentsOf: sshFileUrl)
        print("ssh key content: \(sshKeyContent)")
        let sshKeyType = try SSHKeyDetection.detectPrivateKeyType(from: sshKeyContent)
        print("sshKeyType = \(sshKeyType)")
        switch sshKeyType {
        case .rsa:
            print("RSA key detected")
            let privateKey = try Insecure.RSA.PrivateKey(sshRsa: sshKeyContent)
            sshAuthenticationMethod = .rsa(username: username, privateKey: privateKey)
        case .ed25519:
            print("Ed25519 key detected")
            let privateKey = try Curve25519.Signing.PrivateKey(sshEd25519: sshKeyContent)
            sshAuthenticationMethod = .ed25519(username: username, privateKey: privateKey)
        case .ecdsaP256:
            print("ecdsaP256 key detected")
            let privateKey = try P256.Signing.PrivateKey(pemRepresentation: sshKeyContent) // Does it support OpenSSH key?
            sshAuthenticationMethod = .p256(username: username, privateKey: privateKey)
        case .ecdsaP384:
            print("ecdsaP384 key detected")
            let privateKey = try P384.Signing.PrivateKey(pemRepresentation: sshKeyContent) // Does it support OpenSSH key?
            sshAuthenticationMethod = .p384(username: username, privateKey: privateKey)
        case .ecdsaP521:
            print("ecdsaP521 key detected")
            let privateKey = try P521.Signing.PrivateKey(pemRepresentation: sshKeyContent) // Does it support OpenSSH key?
            sshAuthenticationMethod = .p521(username: username, privateKey: privateKey)
        default:
            print("unsupported key type = \(sshKeyType)")
        }

[Joannis]

Hello @jamesic ! Thanks for reaching out. Why wouldn't this work today?

[jamesic]

Hi @Joannis , when I run the code above, I get the following error. Hence, I guess it doesn't support OpenSSH key format for ECDSA algorithm.

􀟈 Test testSSHKeyType() started.
sshKeyType = ECDSA P-256
ecdsaP256 key detected
􀢄 Test testSSHKeyType() recorded an issue at SshKeyLoginTests.swift:103:6: Caught error: invalidPEMDocument
􀢄 Test testSSHKeyType() failed after 0.734 seconds with 1 issue.
􀢄 Suite SshKeyLoginTests failed after 0.735 seconds with 1 issue.
􀢄 Test run with 1 test in 1 suite failed after 0.735 seconds with 1 issue.
Program ended with exit code: 1

[Joannis]

Right, OpenSSH format isn't in there yet. Makes sense!

[0nurulusoy]

I also get similar error, when trying to authenticate with an RSA private key in OpenSSH format, Citadel throws: Unsupported Key Type: RSA manual parsing not yet implemented. Please use Ed25519.

Fyi. @Joannis

Environment

• Citadel version: 0.11.1
• Swift: 5.9+
• Platform: macOS (App Store sandbox)