Add Nix flake for mciasctl and mciasgrpcctl

Vendor dependencies and expose control program binaries via
nix build. Uses nixpkgs-unstable for Go 1.26 support.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-03-25 21:01:21 -07:00
parent 35e96444aa
commit 115f23a3ea
2485 changed files with 6802335 additions and 0 deletions

View File

@@ -0,0 +1,255 @@
package protocol
import (
"bytes"
"crypto/x509"
"encoding/asn1"
"fmt"
"strings"
"time"
"github.com/go-webauthn/webauthn/metadata"
"github.com/go-webauthn/webauthn/protocol/webauthncose"
)
func init() {
RegisterAttestationFormat(AttestationFormatPacked, attestationFormatValidationHandlerPacked)
}
// attestationFormatValidationHandlerPacked is the handler for the Packed Attestation Statement Format.
//
// The syntax of a Packed Attestation statement is defined by the following CDDL:
//
// $$attStmtType //= (
//
// fmt: "packed",
// attStmt: packedStmtFormat
// )
//
// packedStmtFormat = {
// alg: COSEAlgorithmIdentifier,
// sig: bytes,
// x5c: [ attestnCert: bytes, * (caCert: bytes) ]
// } //
// {
// alg: COSEAlgorithmIdentifier
// sig: bytes,
// }
//
// Specification: §8.2. Packed Attestation Statement Format
//
// See: https://www.w3.org/TR/webauthn/#sctn-packed-attestation
func attestationFormatValidationHandlerPacked(att AttestationObject, clientDataHash []byte, mds metadata.Provider) (attestationType string, x5cs []any, err error) {
var (
alg int64
sig []byte
x5c []any
ok bool
)
// Step 1. Verify that attStmt is valid CBOR conforming to the syntax defined
// above and perform CBOR decoding on it to extract the contained fields.
// Get the alg value - A COSEAlgorithmIdentifier containing the identifier of the algorithm
// used to generate the attestation signature.
if alg, ok = att.AttStatement[stmtAlgorithm].(int64); !ok {
return string(AttestationFormatPacked), nil, ErrAttestationFormat.WithDetails("Error retrieving alg value")
}
// Get the sig value - A byte string containing the attestation signature.
if sig, ok = att.AttStatement[stmtSignature].([]byte); !ok {
return string(AttestationFormatPacked), nil, ErrAttestationFormat.WithDetails("Error retrieving sig value")
}
// Step 2. If x5c is present, this indicates that the attestation type is not ECDAA.
if x5c, ok = att.AttStatement[stmtX5C].([]any); ok {
// Handle Basic Attestation steps for the x509 Certificate.
return handleBasicAttestation(sig, clientDataHash, att.RawAuthData, att.AuthData.AttData.AAGUID, alg, x5c, mds)
}
// Step 3. If ecdaaKeyId is present, then the attestation type is ECDAA.
// Also make sure the we did not have an x509.
ecdaaKeyID, ecdaaKeyPresent := att.AttStatement[stmtECDAAKID].([]byte)
if ecdaaKeyPresent {
// Handle ECDAA Attestation steps for the x509 Certificate.
return handleECDAAAttestation(sig, clientDataHash, ecdaaKeyID, mds)
}
// Step 4. If neither x5c nor ecdaaKeyId is present, self attestation is in use.
return handleSelfAttestation(alg, att.AuthData.AttData.CredentialPublicKey, att.RawAuthData, clientDataHash, sig, mds)
}
// Handle the attestation steps laid out in the basic format.
func handleBasicAttestation(sig, clientDataHash, authData, aaguid []byte, alg int64, x5c []any, _ metadata.Provider) (attestationType string, x5cs []any, err error) {
// Step 2.1. Verify that sig is a valid signature over the concatenation of authenticatorData
// and clientDataHash using the attestation public key in attestnCert with the algorithm specified in alg.
var attestnCert *x509.Certificate
for i, raw := range x5c {
rawByes, ok := raw.([]byte)
if !ok {
return "", x5c, ErrAttestation.WithDetails("Error getting certificate from x5c cert chain")
}
cert, err := x509.ParseCertificate(rawByes)
if err != nil {
return "", x5c, ErrAttestationFormat.WithDetails(fmt.Sprintf("Error parsing certificate from ASN.1 data: %+v", err)).WithError(err)
}
if cert.NotBefore.After(time.Now()) || cert.NotAfter.Before(time.Now()) {
return "", x5c, ErrAttestationFormat.WithDetails("Cert in chain not time valid")
}
if i == 0 {
attestnCert = cert
}
}
if attestnCert == nil {
return "", x5c, ErrAttestation.WithDetails("Error getting certificate from x5c cert chain")
}
signatureData := append(authData, clientDataHash...) //nolint:gocritic // This is intentional.
if sigAlg := webauthncose.SigAlgFromCOSEAlg(webauthncose.COSEAlgorithmIdentifier(alg)); sigAlg == x509.UnknownSignatureAlgorithm {
return "", nil, ErrInvalidAttestation.WithDetails(fmt.Sprintf("Unsupported COSE alg: %d", alg))
} else if err = attestnCert.CheckSignature(sigAlg, signatureData, sig); err != nil {
return "", nil, ErrInvalidAttestation.WithDetails(fmt.Sprintf("Signature validation error: %+v", err)).WithError(err)
}
// Step 2.2 Verify that attestnCert meets the requirements in §8.2.1 Packed attestation statement certificate requirements.
// §8.2.1 can be found here https://www.w3.org/TR/webauthn/#packed-attestation-cert-requirements
// Step 2.2.1 (from §8.2.1) Version MUST be set to 3 (which is indicated by an ASN.1 INTEGER with value 2).
if attestnCert.Version != 3 {
return "", x5c, ErrAttestationCertificate.WithDetails("Attestation Certificate is incorrect version")
}
// Step 2.2.2 (from §8.2.1) Subject field MUST be set to:
// Subject-C
// ISO 3166 code specifying the country where the Authenticator vendor is incorporated (PrintableString).
// TODO: Find a good, usable, country code library. For now, check stringy-ness
subjectString := strings.Join(attestnCert.Subject.Country, "")
if subjectString == "" {
return "", x5c, ErrAttestationCertificate.WithDetails("Attestation Certificate Country Code is invalid")
}
// Subject-O
// Legal name of the Authenticator vendor (UTF8String).
subjectString = strings.Join(attestnCert.Subject.Organization, "")
if subjectString == "" {
return "", x5c, ErrAttestationCertificate.WithDetails("Attestation Certificate Organization is invalid")
}
// Subject-OU
// Literal string “Authenticator Attestation” (UTF8String).
subjectString = strings.Join(attestnCert.Subject.OrganizationalUnit, " ")
if subjectString != "Authenticator Attestation" {
return "", x5c, ErrAttestationCertificate.WithDetails("Attestation Certificate Organizational Unit is invalid")
}
// Subject-CN
// A UTF8String of the vendors choosing.
subjectString = attestnCert.Subject.CommonName
if subjectString == "" {
return "", x5c, ErrAttestationCertificate.WithDetails("Attestation Certificate Common Name not set")
}
// Step 2.2.3 (from §8.2.1) If the related attestation root certificate is used for multiple authenticator models,
// the Extension OID 1.3.6.1.4.1.45724.1.1.4 (id-fido-gen-ce-aaguid) MUST be present, containing the
// AAGUID as a 16-byte OCTET STRING. The extension MUST NOT be marked as critical.
var foundAAGUID []byte
for _, extension := range attestnCert.Extensions {
if extension.Id.Equal(oidFIDOGenCeAAGUID) {
if extension.Critical {
return "", x5c, ErrInvalidAttestation.WithDetails("Attestation certificate FIDO extension marked as critical")
}
foundAAGUID = extension.Value
}
}
// We validate the AAGUID as mentioned above
// This is not well defined in§8.2.1 but mentioned in step 2.3: we validate the AAGUID if it is present within the certificate
// and make sure it matches the auth data AAGUID
// Note that an X.509 Extension encodes the DER-encoding of the value in an OCTET STRING. Thus, the
// AAGUID MUST be wrapped in two OCTET STRINGS to be valid.
if len(foundAAGUID) > 0 {
var unMarshalledAAGUID []byte
if _, err = asn1.Unmarshal(foundAAGUID, &unMarshalledAAGUID); err != nil {
return "", x5c, ErrInvalidAttestation.WithDetails("Error unmarshalling AAGUID from certificate")
}
if !bytes.Equal(aaguid, unMarshalledAAGUID) {
return "", x5c, ErrInvalidAttestation.WithDetails("Certificate AAGUID does not match Auth Data certificate")
}
}
// Step 2.2.4 The Basic Constraints extension MUST have the CA component set to false.
if attestnCert.IsCA {
return "", x5c, ErrInvalidAttestation.WithDetails("Attestation certificate's Basic Constraints marked as CA")
}
// Note for 2.2.5 An Authority Information Access (AIA) extension with entry id-ad-ocsp and a CRL
// Distribution Point extension [RFC5280](https://www.w3.org/TR/webauthn/#biblio-rfc5280) are
// both OPTIONAL as the status of many attestation certificates is available through authenticator
// metadata services. See, for example, the FIDO Metadata Service
// [FIDOMetadataService] (https://www.w3.org/TR/webauthn/#biblio-fidometadataservice)
// Step 2.4 If successful, return attestation type Basic and attestation trust path x5c.
// We don't handle trust paths yet but we're done.
return string(metadata.BasicFull), x5c, nil
}
func handleECDAAAttestation(sig, clientDataHash, ecdaaKeyID []byte, _ metadata.Provider) (attestationType string, x5cs []any, err error) {
return "Packed (ECDAA)", nil, ErrNotSpecImplemented
}
func handleSelfAttestation(alg int64, pubKey, authData, clientDataHash, sig []byte, _ metadata.Provider) (attestationType string, x5cs []any, err error) {
verificationData := append(authData, clientDataHash...) //nolint:gocritic // This is intentional.
var (
key any
valid bool
)
if key, err = webauthncose.ParsePublicKey(pubKey); err != nil {
return "", nil, ErrAttestationFormat.WithDetails(fmt.Sprintf("Error parsing the public key: %+v", err))
}
// §4.1 Validate that alg matches the algorithm of the credentialPublicKey in authenticatorData.
switch k := key.(type) {
case webauthncose.OKPPublicKeyData:
err = verifyKeyAlgorithm(k.Algorithm, alg)
case webauthncose.EC2PublicKeyData:
err = verifyKeyAlgorithm(k.Algorithm, alg)
case webauthncose.RSAPublicKeyData:
err = verifyKeyAlgorithm(k.Algorithm, alg)
default:
return "", nil, ErrInvalidAttestation.WithDetails("Error verifying the public key data")
}
if err != nil {
return "", nil, err
}
// §4.2 Verify that sig is a valid signature over the concatenation of authenticatorData and
// clientDataHash using the credential public key with alg.
if valid, err = webauthncose.VerifySignature(key, verificationData, sig); err != nil {
return "", nil, ErrAttestationFormat.WithDetails(fmt.Sprintf("Error verifying the signature: %+v", err)).WithError(err)
} else if !valid {
return "", nil, ErrInvalidAttestation.WithDetails("Unable to verify signature")
}
return string(metadata.BasicSurrogate), nil, err
}
func verifyKeyAlgorithm(keyAlgorithm, attestedAlgorithm int64) error {
if keyAlgorithm != attestedAlgorithm {
return ErrInvalidAttestation.WithDetails("Public key algorithm does not equal att statement algorithm")
}
return nil
}