Replace homeserver authorization approach with an Authorization header instead of access_token when talking to the application service, as per [MSC2832](matrix-org/matrix-spec-proposals#2832).

Author: benkuly

trixnity-applicationserviceapi/trixnity-applicationserviceapi-server/src/commonMain/kotlin/net/folivo/trixnity/applicationserviceapi/server/MatrixQueryParameterAuth.kt

@@ -0,0 +1,69 @@
+package net.folivo.trixnity.applicationserviceapi.server
+
+import io.ktor.http.*
+import io.ktor.http.auth.*
+import io.ktor.server.auth.*
+import io.ktor.server.request.*
+import io.ktor.server.response.*
+import net.folivo.trixnity.core.ErrorResponse
+
+class MatrixQueryParameterOrBearerAuthenticationProvider internal constructor(
+    configuration: Configuration,
+    private val field: String,
+    private val token: String
+) : AuthenticationProvider(configuration) {
+    class Configuration internal constructor(name: String? = null) : Config(name)
+
+    override suspend fun onAuthenticate(context: AuthenticationContext) {
+        val queryCredentials = context.call.request.queryParameters[field]
+        val accessTokenCredentials = context.call.request.getAccessTokenFromHeader()
+        val cause = when {
+            queryCredentials == null && accessTokenCredentials == null -> AuthenticationFailedCause.NoCredentials
+            accessTokenCredentials != null && queryCredentials != null && accessTokenCredentials != queryCredentials
+                    || (accessTokenCredentials == null && queryCredentials != token)
+                    || (queryCredentials == null && accessTokenCredentials != token)
+                    || (accessTokenCredentials == queryCredentials && queryCredentials != token) -> AuthenticationFailedCause.InvalidCredentials
+
+            else -> null
+        }
+
+        if (cause != null) {
+            context.challenge("MatrixQueryParameterAuth", cause) { challenge, call ->
+                when (cause) {
+                    AuthenticationFailedCause.NoCredentials ->
+                        call.respond<ErrorResponse>(HttpStatusCode.Unauthorized, ErrorResponse.Unauthorized())
+
+                    else -> call.respond<ErrorResponse>(HttpStatusCode.Forbidden, ErrorResponse.Forbidden())
+                }
+                challenge.complete()
+            }
+        } else {
+            context.principal(UserIdPrincipal("homeserver"))
+        }
+    }
+}
+
+private fun ApplicationRequest.getAccessTokenFromHeader(): String? {
+    return when (val authHeader = parseAuthorizationHeader()) {
+        is HttpAuthHeader.Single -> {
+            if (!authHeader.authScheme.equals("Bearer", ignoreCase = true)) null
+            else authHeader.blob
+        }
+
+        else -> null
+    }
+}
+
+fun AuthenticationConfig.matrixQueryParameterOrBearer(
+    name: String? = null,
+    field: String,
+    token: String,
+) {
+    val provider =
+        MatrixQueryParameterOrBearerAuthenticationProvider(
+            MatrixQueryParameterOrBearerAuthenticationProvider.Configuration(name),
+            field,
+            token
+        )
+    register(provider)
+}

trixnity-applicationserviceapi/trixnity-applicationserviceapi-server/src/commonMain/kotlin/net/folivo/trixnity/applicationserviceapi/server/MatrixQueryParameterOrBearerAuth.kt

@@ -16,7 +16,7 @@ fun Application.matrixApplicationServiceApiServer(
     routes: Route.() -> Unit,
 ) {
     install(Authentication) {
-        matrixQueryParameter("matrix-query-parameter-auth", "access_token", hsToken)
+        matrixQueryParameterOrBearer("matrix-query-parameter-auth", "access_token", hsToken)
     }
     matrixApiServer(json) {
         authenticate("matrix-query-parameter-auth") {

trixnity-applicationserviceapi/trixnity-applicationserviceapi-server/src/commonMain/kotlin/net/folivo/trixnity/applicationserviceapi/server/matrixApplicationServiceApiServer.kt

@@ -23,7 +23,7 @@ private fun Application.testAppMatrixQueryParameterAuth() {
         json()
     }
     install(Authentication) {
-        matrixQueryParameter(null, "access_token", "validToken")
+        matrixQueryParameterOrBearer(null, "access_token", "validToken")
     }
     routing {
         authenticate {
@@ -34,10 +34,10 @@ private fun Application.testAppMatrixQueryParameterAuth() {
     }
 }
 
-class MatrixQueryParameterAuthTest {
+class MatrixQueryParameterOrBearerAuthTest {
 
     @Test
-    fun `should forbid missing token`() = testApplication {
+    fun `should forbid missing query or auth token`() = testApplication {
         application { testAppMatrixQueryParameterAuth() }
         val response = client.get("/_matrix/something")
         assertEquals(HttpStatusCode.Unauthorized, response.status)
@@ -47,7 +47,7 @@ class MatrixQueryParameterAuthTest {
     }
 
     @Test
-    fun `should forbid wrong token`() = testApplication {
+    fun `should forbid wrong query token`() = testApplication {
         application { testAppMatrixQueryParameterAuth() }
         val response = client.get("/_matrix/something?access_token=invalidToken")
         assertEquals(HttpStatusCode.Forbidden, response.status)
@@ -57,9 +57,42 @@ class MatrixQueryParameterAuthTest {
     }
 
     @Test
-    fun `should permit right token`() = testApplication {
+    fun `should forbid wrong header token`() = testApplication {
+        application { testAppMatrixQueryParameterAuth() }
+        val response = client.get("/_matrix/something") {
+            bearerAuth("invalidToken")
+        }
+        assertEquals(HttpStatusCode.Forbidden, response.status)
+        assertEquals(ContentType.Application.Json.withCharset(UTF_8), response.contentType())
+        Json.decodeFromString(ErrorResponseSerializer, response.body())
+            .shouldBeInstanceOf<ErrorResponse.Forbidden>()
+    }
+
+    @Test
+    fun `should forbid non matching token`() = testApplication {
+        application { testAppMatrixQueryParameterAuth() }
+        val response = client.get("/_matrix/something?access_token=validToken") {
+            bearerAuth("invalidToken")
+        }
+        assertEquals(HttpStatusCode.Forbidden, response.status)
+        assertEquals(ContentType.Application.Json.withCharset(UTF_8), response.contentType())
+        Json.decodeFromString(ErrorResponseSerializer, response.body())
+            .shouldBeInstanceOf<ErrorResponse.Forbidden>()
+    }
+
+    @Test
+    fun `should permit right query token`() = testApplication {
         application { testAppMatrixQueryParameterAuth() }
         val response = client.get("/_matrix/something?access_token=validToken")
         assertEquals(HttpStatusCode.OK, response.status)
     }
+
+    @Test
+    fun `should permit right header token`() = testApplication {
+        application { testAppMatrixQueryParameterAuth() }
+        val response = client.get("/_matrix/something") {
+            bearerAuth("validToken")
+        }
+        assertEquals(HttpStatusCode.OK, response.status)
+    }
 }