Throw if silent assert request requires showing UI

apps/desktop/src/autofill/services/desktop-autofill.service.ts

@@ -307,7 +307,7 @@ export class DesktopAutofillService implements OnDestroy {
           }
 
           const response = await this.fido2AuthenticatorService.getAssertion(
-            this.convertAssertionRequest(request, true),
+            this.convertAssertionRequest(request, { assumeUserPresence: true, isSilent: true }),
             { windowXy: request.windowXy, handle: clientHandle },
             controller,
             request.context,
@@ -453,15 +453,20 @@ export class DesktopAutofillService implements OnDestroy {
   /**
    *
    * @param request
-   * @param assumeUserPresence For WithoutUserInterface requests, we assume the user is present
+   * @param options For WithoutUserInterface requests, we assume user presence and throw errors if we cannot fulfill the request silently.
    * @returns
    */
   private convertAssertionRequest(
     request:
       | autofill.PasskeyAssertionRequest
       | autofill.PasskeyAssertionWithoutUserInterfaceRequest,
-    assumeUserPresence: boolean = false,
+    options?: {
+      assumeUserPresence?: boolean,
+      isSilent?: boolean,
+    }
+
   ): Fido2AuthenticatorGetAssertionParams {
+    const { assumeUserPresence, isSilent } = options ?? {};
     let allowedCredentials;
     if ("credentialId" in request) {
       allowedCredentials = [
@@ -486,6 +491,7 @@ export class DesktopAutofillService implements OnDestroy {
         request.userVerification === "required" || request.userVerification === "preferred",
       fallbackSupported: false,
       assumeUserPresence,
+      isSilent,
     };
   }
 

apps/desktop/src/autofill/services/desktop-fido2-user-interface.service.ts

@@ -18,6 +18,7 @@ import {
   Fido2UserInterfaceSession,
   NewCredentialParams,
   PickCredentialParams,
+UserInteractionRequired,
 } from "@bitwarden/common/platform/abstractions/fido2/fido2-user-interface.service.abstraction";
 import { LogService } from "@bitwarden/common/platform/abstractions/log.service";
 import { MessagingService } from "@bitwarden/common/platform/abstractions/messaging.service";
@@ -130,18 +131,20 @@ export class DesktopFido2UserInterfaceSession implements Fido2UserInterfaceSessi
     userVerification,
     assumeUserPresence,
     masterPasswordRepromptRequired,
+    isSilent,
   }: PickCredentialParams): Promise<{ cipherId: string; userVerified: boolean }> {
     this.logService.debug("pickCredential desktop function", {
       cipherIds,
       userVerification,
       assumeUserPresence,
       masterPasswordRepromptRequired,
+      isSilent,
     });
 
     try {
       // Check if we can return the credential without user interaction
       await this.accountService.setShowHeader(false);
-      if (assumeUserPresence && cipherIds.length === 1 && !masterPasswordRepromptRequired) {
+      if (cipherIds.length === 1 && !masterPasswordRepromptRequired) {
         const selectedCipherId = cipherIds[0];
         if (userVerification) {
           // retrieve the cipher
@@ -166,7 +169,7 @@ export class DesktopFido2UserInterfaceSession implements Fido2UserInterfaceSessi
             this.logService.debug("Failed to prompt for user verification without showing UI", e)
           }
         }
-        else {
+        else if (assumeUserPresence) {
           this.logService.warning(
             "shortcut - Assuming user presence and returning cipherId",
             cipherIds[0],
@@ -175,11 +178,13 @@ export class DesktopFido2UserInterfaceSession implements Fido2UserInterfaceSessi
         }
       }
 
-      this.logService.debug("Could not shortcut, showing UI");
-
-      // TODO: We need to pass context from the original request whether this
-      // should be a silent request or not. Then, we can fail here if it's
-      // supposed to be silent.
+      if (isSilent) {
+        this.logService.info("Could not fulfill request silently, aborting request");
+        throw new UserInteractionRequired()
+      }
+      else {
+        this.logService.debug("Could not shortcut, showing UI");
+      }
 
       // make the cipherIds available to the UI.
       this.availableCipherIdsSubject.next(cipherIds);

libs/common/src/platform/abstractions/fido2/fido2-authenticator.service.abstraction.ts

@@ -153,8 +153,14 @@ export interface Fido2AuthenticatorGetAssertionParams {
   /** Forwarded to user interface */
   fallbackSupported: boolean;
 
-  // Bypass the UI and assume that the user has already interacted with the authenticator
+  /** Bypass the UI and assume that the user has already interacted with the authenticator */
   assumeUserPresence?: boolean;
+
+  /** Signals whether an error should be thrown if an assertion cannot be obtained without showing Bitwarden UI.
+   *
+   * Note that OS user verification prompts are allowed in silent requests.
+  */
+  isSilent?: boolean;
 }
 
 export interface Fido2AuthenticatorGetAssertionResult {

libs/common/src/platform/abstractions/fido2/fido2-user-interface.service.abstraction.ts

@@ -50,6 +50,12 @@ export interface PickCredentialParams {
    * Identifies whether a cipher requires a master password reprompt when getting a credential.
    */
   masterPasswordRepromptRequired?: boolean;
+
+  /** Signals whether an error should be thrown if an assertion cannot be obtained without showing Bitwarden UI.
+   *
+   * Note that OS user verification prompts are allowed in silent requests.
+  */
+  isSilent?: boolean;
 }
 
 /**
@@ -121,3 +127,6 @@ export abstract class Fido2UserInterfaceSession {
    */
   abstract close(): void;
 }
+
+/** Thrown when user interaction is required during a request for a silent assertion. */
+export class UserInteractionRequired extends Error {}

libs/common/src/platform/services/fido2/fido2-authenticator.service.ts

@@ -291,6 +291,7 @@ export class Fido2AuthenticatorService<
           userVerification: params.requireUserVerification,
           assumeUserPresence: params.assumeUserPresence,
           masterPasswordRepromptRequired,
+          isSilent: params.isSilent,
         });
       }