avoid using the SDK to decrypt attachments for emergency access (#16293)

- The SDK does not have emergency access functionality built in at this point.

libs/common/src/vault/abstractions/cipher.service.ts

@@ -257,6 +257,10 @@ export abstract class CipherService implements UserKeyRotationDataProvider<Ciphe
    * @param attachment The attachment view object
    * @param response The response object containing the encrypted content
    * @param userId The user ID whose key will be used for decryption
+   * @param useLegacyDecryption When true, forces the use of the legacy decryption method
+   * even when the SDK feature is enabled. This is helpful for domains of
+   * the application that have yet to be moved into the SDK, i.e. emergency access.
+   * TODO: PM-25469 - this should be obsolete once emergency access is moved to the SDK.
    *
    * @returns A promise that resolves to the decrypted content
    */
@@ -265,6 +269,7 @@ export abstract class CipherService implements UserKeyRotationDataProvider<Ciphe
     attachment: AttachmentView,
     response: Response,
     userId: UserId,
+    useLegacyDecryption?: boolean,
   ): Promise<Uint8Array | null>;
 
   /**

libs/common/src/vault/services/cipher.service.ts

@@ -1544,11 +1544,13 @@ export class CipherService implements CipherServiceAbstraction {
     return encryptedCiphers;
   }
 
+  /** @inheritdoc */
   async getDecryptedAttachmentBuffer(
     cipherId: CipherId,
     attachment: AttachmentView,
     response: Response,
     userId: UserId,
+    useLegacyDecryption?: boolean,
   ): Promise<Uint8Array> {
     const useSdkDecryption = await this.configService.getFeatureFlag(
       FeatureFlag.PM19941MigrateCipherDomainToSdk,
@@ -1558,7 +1560,7 @@ export class CipherService implements CipherServiceAbstraction {
       this.ciphers$(userId).pipe(map((ciphersData) => new Cipher(ciphersData[cipherId]))),
     );
 
-    if (useSdkDecryption) {
+    if (useSdkDecryption && !useLegacyDecryption) {
       const encryptedContent = await response.arrayBuffer();
       return this.cipherEncryptionService.decryptAttachmentContent(
         cipherDomain,

libs/vault/src/components/download-attachment/download-attachment.component.ts

@@ -92,6 +92,9 @@ export class DownloadAttachmentComponent {
         this.attachment,
         response,
         userId,
+        // When the emergency access ID is present, the cipher is being viewed via emergency access.
+        // Force legacy decryption in these cases.
+        this.emergencyAccessId ? true : false,
       );
 
       this.fileDownloadService.download({