Add support for reading accounts from Element Classic.

2026-11-04 19:11:45 +00:00 · 2025-10-10 16:44:26 +02:00
parent ac56a0ba43
commit 95b3a8fbb1
18 changed files with 775 additions and 3 deletions
@@ -0,0 +1,78 @@
+//
+// Copyright 2026 Element Creations Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+// Please see LICENSE files in the repository root for full details.
+//
+
+import CommonCrypto
+import Foundation
+
+enum ClassicAppAES {
+    enum Error: Swift.Error {
+        case cannotInitializeCryptor
+        case decryptionFailed(CCCryptorStatus)
+    }
+    
+    /// Decrypt data using AES-256 in CTR mode.
+    /// - Parameters:
+    ///   - data: The data to decrypt
+    ///   - aesKey: The AES decryption key (256-bit)
+    ///   - iv: The initialization vector
+    /// - Returns: The decrypted data, or nil if decryption fails
+    /// - Throws: An error if decryption fails
+    static func decrypt(_ data: Data, aesKey: Data, iv: Data) throws -> Data {
+        var cryptor: CCCryptorRef?
+        var status: CCCryptorStatus
+        
+        // Create the cryptor
+        status = iv.withUnsafeBytes { ivBytes in
+            aesKey.withUnsafeBytes { keyBytes in
+                CCCryptorCreateWithMode(CCOperation(kCCDecrypt),
+                                        CCMode(kCCModeCTR),
+                                        CCAlgorithm(kCCAlgorithmAES),
+                                        CCPadding(ccNoPadding),
+                                        ivBytes.baseAddress,
+                                        keyBytes.baseAddress,
+                                        kCCKeySizeAES256,
+                                        nil,
+                                        0,
+                                        0,
+                                        CCModeOptions(kCCModeOptionCTR_BE),
+                                        &cryptor)
+            }
+        }
+        
+        guard status == kCCSuccess, let cryptor else {
+            MXLog.error("Failed to create cryptor: \(status)")
+            throw Error.cannotInitializeCryptor
+        }
+        
+        // Get the output buffer size
+        let bufferLength = CCCryptorGetOutputLength(cryptor, data.count, false)
+        var buffer = Data(count: bufferLength)
+        
+        var outLength = 0
+        status = data.withUnsafeBytes { dataBytes in
+            let count = buffer.count
+            return buffer.withUnsafeMutableBytes { bufferBytes in
+                CCCryptorUpdate(cryptor,
+                                dataBytes.baseAddress,
+                                data.count,
+                                bufferBytes.baseAddress,
+                                count,
+                                &outLength)
+            }
+        }
+        
+        let releaseStatus = CCCryptorRelease(cryptor)
+        status = (status == kCCSuccess && releaseStatus == kCCSuccess) ? CCCryptorStatus(kCCSuccess) : status
+        
+        guard status == kCCSuccess else {
+            MXLog.error("Decryption failed: \(status)")
+            throw Error.decryptionFailed(status)
+        }
+        
+        return buffer
+    }
+}