Get password from keychain using persistent reference

OpenVPN Tunnel Provider/KeychainAccess+Reference.swift

@@ -0,0 +1,45 @@
+//
+//  KeychainAccess+Reference.swift
+//  OpenVPN iOS Client
+//
+//  Created by Sergey Abramchuk on 07.03.17.
+//
+//
+
+import Foundation
+import KeychainAccess
+
+extension Keychain {
+    
+    public func get(ref: Data) throws -> String? {
+        guard let data = try getData(ref: ref) else {
+            return nil
+        }
+        
+        return String(data: data, encoding: .utf8)
+    }
+    
+    public func getData(ref: Data) throws -> Data? {
+        let query: [String: Any] = [
+            String(kSecClass): itemClass.rawValue,
+            String(kSecReturnData): kCFBooleanTrue,
+            String(kSecValuePersistentRef): ref as CFData
+        ]
+        
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        
+        switch status {
+        case errSecSuccess:
+            guard let data = result as? Data else {
+                throw Status.unexpectedError
+            }
+            return data
+        case errSecItemNotFound:
+            return nil
+        default:
+            throw Status(status: status)
+        }
+    }
+    
+}

OpenVPN iOS Client.xcodeproj/project.pbxproj

@@ -20,6 +20,7 @@
 		C910313F1E4732080004DFFE /* liblz4.a in Frameworks */ = {isa = PBXBuildFile; fileRef = C910313E1E4732080004DFFE /* liblz4.a */; };
 		C91031411E4732160004DFFE /* libmbedtls.a in Frameworks */ = {isa = PBXBuildFile; fileRef = C91031401E4732160004DFFE /* libmbedtls.a */; };
 		C91031461E47345F0004DFFE /* ovpncli.cpp in Sources */ = {isa = PBXBuildFile; fileRef = C91031451E47345F0004DFFE /* ovpncli.cpp */; };
+		C928AD731E6E952F00DA04BD /* KeychainAccess+Reference.swift in Sources */ = {isa = PBXBuildFile; fileRef = C928AD721E6E952F00DA04BD /* KeychainAccess+Reference.swift */; };
 		C9990B391E62F60400474227 /* TUNConfiguration.m in Sources */ = {isa = PBXBuildFile; fileRef = C9990B381E62F60400474227 /* TUNConfiguration.m */; };
 /* End PBXBuildFile section */
 
@@ -72,6 +73,7 @@
 		C91031431E47345E0004DFFE /* Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "Bridging-Header.h"; sourceTree = "<group>"; };
 		C91031441E47345F0004DFFE /* ovpncli.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; name = ovpncli.hpp; path = Vendors/openvpn/openvpn/client/ovpncli.hpp; sourceTree = "<group>"; };
 		C91031451E47345F0004DFFE /* ovpncli.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = ovpncli.cpp; path = Vendors/openvpn/openvpn/client/ovpncli.cpp; sourceTree = "<group>"; };
+		C928AD721E6E952F00DA04BD /* KeychainAccess+Reference.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "KeychainAccess+Reference.swift"; sourceTree = "<group>"; };
 		C9990B361E62F0E800474227 /* OpenVPN Client.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = "OpenVPN Client.entitlements"; sourceTree = "<group>"; };
 		C9990B371E62F60400474227 /* TUNConfiguration.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = TUNConfiguration.h; sourceTree = "<group>"; };
 		C9990B381E62F60400474227 /* TUNConfiguration.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = TUNConfiguration.m; sourceTree = "<group>"; };
@@ -262,6 +264,7 @@
 		C91031341E4729270004DFFE /* Helpers */ = {
 			isa = PBXGroup;
 			children = (
+				C928AD711E6E94FE00DA04BD /* Extensions */,
 			);
 			name = Helpers;
 			sourceTree = "<group>";
@@ -293,6 +296,14 @@
 			name = OpenVPN;
 			sourceTree = "<group>";
 		};
+		C928AD711E6E94FE00DA04BD /* Extensions */ = {
+			isa = PBXGroup;
+			children = (
+				C928AD721E6E952F00DA04BD /* KeychainAccess+Reference.swift */,
+			);
+			name = Extensions;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */
@@ -488,6 +499,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				C91031271E4727E20004DFFE /* PacketTunnelProvider.swift in Sources */,
+				C928AD731E6E952F00DA04BD /* KeychainAccess+Reference.swift in Sources */,
 				C91031461E47345F0004DFFE /* ovpncli.cpp in Sources */,
 				C909DF7D1E4F303F000999B2 /* OpenVPNAdapter.mm in Sources */,
 				C909DF751E4F2528000999B2 /* OpenVPNClient.mm in Sources */,