@ -1177,6 +1177,61 @@ fn passkey_transports(passkey: &Passkey) -> Vec<String> {
. unwrap_or_default ( )
}
/// Augments the base login response (from `authenticated_response`) with the credential-
/// specific `WebAuthnPrfOption` field that upstream Bitwarden's `UserDecryptionOptionsBuilder`
/// attaches via `WithWebAuthnLoginCredential` after a successful passkey assertion. Without
/// this attachment the client receives a valid access token but no way to unlock the vault
/// from the PRF secret it just derived — login completes, vault stays locked.
pub ( crate ) fn build_webauthn_login_response ( base : Value , matched_wac : & WebAuthnCredential , passkey : & Passkey ) -> Value {
let mut result = base ;
if let Some ( prf_option ) = build_webauthn_login_prf_option ( matched_wac , passkey ) {
result [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] = prf_option ;
}
result
}
/// Singular `WebAuthnPrfOption` for the webauthn-login response. The Bitwarden client's
/// immediate post-passkey-login decryption path reads this field to recover the user key from
/// the PRF output the assertion just produced. Gated on `has_prf_keyset()` so we never
/// advertise PRF capability for a credential whose keyset is incomplete.
pub ( crate ) fn build_webauthn_login_prf_option ( matched_wac : & WebAuthnCredential , passkey : & Passkey ) -> Option < Value > {
if ! matched_wac . has_prf_keyset ( ) {
return None ;
}
let credential_id = passkey_credential_id ( passkey ) . ok ( ) ? ;
let transports = passkey_transports ( passkey ) ;
Some ( json ! ( {
"EncryptedPrivateKey" : matched_wac . encrypted_private_key ,
"EncryptedUserKey" : matched_wac . encrypted_user_key ,
"CredentialId" : credential_id ,
"Transports" : transports ,
} ) )
}
/// `WebAuthnPrfOptions` array for `UserDecryptionOptions` (login response) and
/// `userDecryption` (sync response). Only credentials with `prf_status() == Enabled`
/// (supports PRF + complete keyset) appear; corrupted blobs are filter_map'd out
/// so one broken row doesn't suppress the lock-screen option for healthy
/// credentials. Mirrors upstream
/// `SyncResponseModel.UserDecryption.WebAuthnPrfOptions`.
pub ( crate ) fn build_webauthn_prf_options ( credentials : & [ WebAuthnCredential ] ) -> Vec < Value > {
credentials
. iter ( )
. filter ( | wac | wac . has_prf_keyset ( ) )
. filter_map ( | wac | {
let passkey : Passkey = serde_json ::from_str ( & wac . credential ) . ok ( ) ? ;
let credential_id = passkey_credential_id ( & passkey ) . ok ( ) ? ;
let transports = passkey_transports ( & passkey ) ;
Some ( json ! ( {
"EncryptedPrivateKey" : wac . encrypted_private_key ,
"EncryptedUserKey" : wac . encrypted_user_key ,
"CredentialId" : credential_id ,
"Transports" : transports ,
} ) )
} )
. collect ( )
}
#[ get( " /accounts/webauthn/assertion-options " ) ]
async fn get_web_authn_assertion_options ( ip : ClientIp , conn : DbConn ) -> JsonResult {
// Same gate the 2FA WebAuthn entry point uses, applied here so a
@ -1398,25 +1453,12 @@ async fn webauthn_login(data: ConnectData, user_id: &mut Option<UserId>, conn: &
let auth_tokens = auth ::AuthTokens ::new ( & device , & user , AuthMethod ::WebAuthn , data . client_id ) ;
// Build response using the common authenticated_response helper
let mut result = authenticated_response ( & user , & mut device , auth_tokens , None , conn , ip ) . await ? ;
// Add WebAuthnPrfOption only when the credential is in the PRF "Enabled"
// state (supports_prf + all three encrypted blobs present), matching
// Bitwarden's `GetPrfStatus() == Enabled` gate.
if matched_wac . has_prf_keyset ( ) {
let credential_id = passkey_credential_id ( & passkey ) ? ;
let transports = passkey_transports ( & passkey ) ;
let Json ( ref mut val ) = result ;
val [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] = json ! ( {
"EncryptedPrivateKey" : matched_wac . encrypted_private_key ,
"EncryptedUserKey" : matched_wac . encrypted_user_key ,
"CredentialId" : credential_id ,
"Transports" : transports ,
} ) ;
}
Ok ( result )
// Build the common response, then attach the credential-specific `WebAuthnPrfOption`
// upstream populates via `WithWebAuthnLoginCredential` after a webauthn-grant assertion.
// The wrapped-key payload lets the client unlock the vault using the PRF secret it just
// derived; without it, login completes but the vault stays locked.
let Json ( base ) = authenticated_response ( & user , & mut device , auth_tokens , None , conn , ip ) . await ? ;
Ok ( Json ( build_webauthn_login_response ( base , & matched_wac , & passkey ) ) )
}
// https://github.com/bitwarden/jslib/blob/master/common/src/models/request/tokenRequest.ts
@ -1693,4 +1735,209 @@ mod tests {
fn passkey_transports_defaults_to_empty_when_absent ( ) {
assert ! ( passkey_transports ( & passkey ( None ) ) . is_empty ( ) ) ;
}
fn make_credential (
supports_prf : bool ,
encrypted_user_key : Option < & str > ,
encrypted_public_key : Option < & str > ,
encrypted_private_key : Option < & str > ,
passkey_json : & str ,
) -> WebAuthnCredential {
WebAuthnCredential ::new (
UserId ::from ( String ::from ( "00000000-0000-0000-0000-000000000000" ) ) ,
String ::from ( "test" ) ,
passkey_json . to_owned ( ) ,
String ::from ( "credential-id-hash" ) ,
supports_prf ,
encrypted_user_key . map ( String ::from ) ,
encrypted_public_key . map ( String ::from ) ,
encrypted_private_key . map ( String ::from ) ,
)
}
#[ test ]
fn webauthn_prf_options_skips_credentials_without_full_keyset ( ) {
let pk = serde_json ::to_string ( & passkey ( None ) ) . unwrap ( ) ;
let creds = [
make_credential ( false , Some ( "u" ) , Some ( "p" ) , Some ( "k" ) , & pk ) , // PRF unsupported
make_credential ( true , None , None , None , & pk ) , // PRF supported, no keyset
make_credential ( true , Some ( "u" ) , Some ( "p" ) , None , & pk ) , // partial keyset
] ;
assert ! ( build_webauthn_prf_options ( & creds ) . is_empty ( ) ) ;
}
#[ test ]
fn webauthn_prf_options_emits_entry_per_enabled_credential ( ) {
let pk = serde_json ::to_string ( & passkey ( Some ( vec ! [ AuthenticatorTransport ::Internal ] ) ) ) . unwrap ( ) ;
let creds = [
make_credential ( true , Some ( "uk-a" ) , Some ( "pk-a" ) , Some ( "priv-a" ) , & pk ) ,
make_credential ( true , Some ( "uk-b" ) , Some ( "pk-b" ) , Some ( "priv-b" ) , & pk ) ,
make_credential ( false , Some ( "uk-c" ) , Some ( "pk-c" ) , Some ( "priv-c" ) , & pk ) , // skipped
] ;
let options = build_webauthn_prf_options ( & creds ) ;
assert_eq ! ( options . len ( ) , 2 , "only PRF-enabled credentials should produce entries" ) ;
// Match upstream `WebAuthnPrfDecryptionOption` field names (PascalCase). The Bitwarden
// client deserialises case-insensitively, but pinning the casing here catches a
// refactor that accidentally renames a key.
assert_eq ! ( options [ 0 ] [ "EncryptedUserKey" ] , "uk-a" ) ;
assert_eq ! ( options [ 0 ] [ "EncryptedPrivateKey" ] , "priv-a" ) ;
assert_eq ! ( options [ 0 ] [ "CredentialId" ] , "AQIDBA" ) ;
assert_eq ! ( options [ 0 ] [ "Transports" ] , json ! ( [ "internal" ] ) ) ;
assert_eq ! ( options [ 1 ] [ "EncryptedUserKey" ] , "uk-b" ) ;
assert_eq ! ( options [ 1 ] [ "EncryptedPrivateKey" ] , "priv-b" ) ;
}
#[ test ]
fn webauthn_login_prf_option_emits_for_enabled_credential ( ) {
// Pins the singular `WebAuthnPrfOption` block emitted by the webauthn-login response.
// The Bitwarden client's post-passkey-login decryption path reads this specific field
// (alongside the plural `WebAuthnPrfOptions` array used by the lock screen). Removing
// it leaves the credential just authenticated with un-usable for immediate vault unlock
// even though the PRF assertion already produced the output the client would decrypt
// with.
let pk = passkey ( Some ( vec ! [ AuthenticatorTransport ::Internal ] ) ) ;
let pk_blob = serde_json ::to_string ( & pk ) . unwrap ( ) ;
let wac = make_credential ( true , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & pk_blob ) ;
let option = build_webauthn_login_prf_option ( & wac , & pk ) . expect ( "PRF-enabled credential emits singular option" ) ;
assert_eq ! ( option [ "EncryptedPrivateKey" ] , "priv" ) ;
assert_eq ! ( option [ "EncryptedUserKey" ] , "uk" ) ;
assert_eq ! ( option [ "CredentialId" ] , "AQIDBA" ) ;
assert_eq ! ( option [ "Transports" ] , json ! ( [ "internal" ] ) ) ;
}
#[ test ]
fn webauthn_login_response_attaches_singular_prf_option_for_enabled_credential ( ) {
// Pins the shape of the `webauthn_login` response augmentation: when a PRF-enabled
// credential authenticates, `UserDecryptionOptions.WebAuthnPrfOption` (singular) is
// attached to the response. Matches upstream Bitwarden's `UserDecryptionOptions`
// contract (singular field, populated only by the webauthn grant via
// `UserDecryptionOptionsBuilder.WithWebAuthnLoginCredential`).
let base = json ! ( {
"UserDecryptionOptions" : {
"HasMasterPassword" : true ,
"Object" : "userDecryptionOptions" ,
}
} ) ;
let pk = passkey ( Some ( vec ! [ AuthenticatorTransport ::Internal ] ) ) ;
let wac = make_credential ( true , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & serde_json ::to_string ( & pk ) . unwrap ( ) ) ;
let response = build_webauthn_login_response ( base , & wac , & pk ) ;
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] [ "EncryptedPrivateKey" ] , "priv" ) ;
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] [ "EncryptedUserKey" ] , "uk" ) ;
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] [ "CredentialId" ] , "AQIDBA" ) ;
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] [ "Transports" ] , json ! ( [ "internal" ] ) ) ;
// Pre-existing fields are preserved.
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "HasMasterPassword" ] , true ) ;
}
#[ test ]
fn webauthn_login_response_omits_singular_prf_option_when_credential_keyset_incomplete ( ) {
// PRF-capable but no keyset (Supported, not Enabled) → no field attached, matching
// upstream's `GetPrfStatus() == Enabled` gate inside `WithWebAuthnLoginCredential`.
let base = json ! ( {
"UserDecryptionOptions" : { "HasMasterPassword" : true , "Object" : "userDecryptionOptions" }
} ) ;
let pk = passkey ( None ) ;
let wac = make_credential ( true , None , None , None , & serde_json ::to_string ( & pk ) . unwrap ( ) ) ;
let response = build_webauthn_login_response ( base , & wac , & pk ) ;
assert ! ( response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] . is_null ( ) ) ;
// Untouched otherwise.
assert_eq ! ( response [ "UserDecryptionOptions" ] [ "HasMasterPassword" ] , true ) ;
}
#[ test ]
fn webauthn_login_response_is_noop_for_prf_unsupported_credential ( ) {
// Behavior: a credential whose authenticator doesn't support PRF (`supports_prf=false`)
// must produce **zero modification** to the response — not a null field, not an empty
// object, nothing. The function's contract is "only emit for Enabled". We assert by
// comparing the whole response to the input.
let base = json ! ( {
"UserDecryptionOptions" : { "HasMasterPassword" : true , "Object" : "userDecryptionOptions" }
} ) ;
let pk = passkey ( None ) ;
// supports_prf=false, even with all blobs present, should still not emit the option.
let wac = make_credential ( false , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & serde_json ::to_string ( & pk ) . unwrap ( ) ) ;
let response = build_webauthn_login_response ( base . clone ( ) , & wac , & pk ) ;
assert_eq ! ( response , base , "PRF-unsupported credential must produce no modification" ) ;
}
#[ test ]
fn webauthn_login_response_lands_user_in_vault_for_prf_enabled_credential ( ) {
// End-to-end behaviour: after a passkey login with a PRF-enabled credential the
// response must carry the wrapped-key payload the client combines with the PRF
// secret from the just-completed assertion to recover the user key and unlock the
// vault. Without it, the client authenticates successfully but lands on the lock
// screen with an MP prompt — which is what triggered the original regression
// report. Pins the contract upstream populates via `WithWebAuthnLoginCredential`.
let base = json ! ( {
"UserDecryptionOptions" : { "HasMasterPassword" : false , "Object" : "userDecryptionOptions" }
} ) ;
let pk = passkey ( Some ( vec ! [ AuthenticatorTransport ::Internal ] ) ) ;
let wac = make_credential ( true , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & serde_json ::to_string ( & pk ) . unwrap ( ) ) ;
let response = build_webauthn_login_response ( base , & wac , & pk ) ;
let prf = & response [ "UserDecryptionOptions" ] [ "WebAuthnPrfOption" ] ;
// All four fields must be present for the client to perform the unlock.
assert ! ( prf . is_object ( ) , "unlock payload must be an object, not null" ) ;
assert ! ( prf [ "EncryptedPrivateKey" ] . as_str ( ) . is_some ( ) , "EncryptedPrivateKey required" ) ;
assert ! ( prf [ "EncryptedUserKey" ] . as_str ( ) . is_some ( ) , "EncryptedUserKey required" ) ;
assert ! ( prf [ "CredentialId" ] . as_str ( ) . is_some ( ) , "CredentialId required" ) ;
assert ! ( prf [ "Transports" ] . is_array ( ) , "Transports required (may be empty)" ) ;
}
#[ test ]
fn webauthn_login_response_is_idempotent_for_enabled_credential ( ) {
// Behavior: calling the augmentation twice on the same inputs produces an identical
// response on each call. Pins that the function is pure (no accumulating side effects)
// and that writing the same key twice doesn't change the structure.
let base = json ! ( {
"UserDecryptionOptions" : { "HasMasterPassword" : true , "Object" : "userDecryptionOptions" }
} ) ;
let pk = passkey ( Some ( vec ! [ AuthenticatorTransport ::Internal ] ) ) ;
let wac = make_credential ( true , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & serde_json ::to_string ( & pk ) . unwrap ( ) ) ;
let once = build_webauthn_login_response ( base , & wac , & pk ) ;
let twice = build_webauthn_login_response ( once . clone ( ) , & wac , & pk ) ;
assert_eq ! ( once , twice , "idempotent application of the augmentation" ) ;
}
#[ test ]
fn webauthn_login_prf_option_suppressed_when_credential_lacks_keyset ( ) {
// PRF-capable but no keyset (Supported status) → no singular emission, matching the
// `GetPrfStatus() == Enabled` gate the original webauthn-login code already applied.
let pk = passkey ( None ) ;
let pk_blob = serde_json ::to_string ( & pk ) . unwrap ( ) ;
let supported_only = make_credential ( true , None , None , None , & pk_blob ) ;
let unsupported = make_credential ( false , Some ( "uk" ) , Some ( "pk" ) , Some ( "priv" ) , & pk_blob ) ;
let partial = make_credential ( true , Some ( "uk" ) , Some ( "pk" ) , None , & pk_blob ) ;
assert ! ( build_webauthn_login_prf_option ( & supported_only , & pk ) . is_none ( ) ) ;
assert ! ( build_webauthn_login_prf_option ( & unsupported , & pk ) . is_none ( ) ) ;
assert ! ( build_webauthn_login_prf_option ( & partial , & pk ) . is_none ( ) ) ;
}
#[ test ]
fn webauthn_prf_options_skips_corrupted_credential_blob ( ) {
// A row whose `credential` column was somehow corrupted should be silently dropped
// rather than aborting the whole response — the lock screen should still surface the
// healthy credentials.
let pk = serde_json ::to_string ( & passkey ( None ) ) . unwrap ( ) ;
let creds = [
make_credential ( true , Some ( "uk-a" ) , Some ( "pk-a" ) , Some ( "priv-a" ) , "not-json" ) ,
make_credential ( true , Some ( "uk-b" ) , Some ( "pk-b" ) , Some ( "priv-b" ) , & pk ) ,
] ;
let options = build_webauthn_prf_options ( & creds ) ;
assert_eq ! ( options . len ( ) , 1 ) ;
assert_eq ! ( options [ 0 ] [ "EncryptedUserKey" ] , "uk-b" ) ;
}
}
Zaid Marji
2 weeks ago