Global counter

SoftU2F.xcodeproj/project.pbxproj

@@ -85,6 +85,9 @@
 		F738F5871E4A3C09005680A2 /* DataReaderTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = F738F5851E4A3C09005680A2 /* DataReaderTests.swift */; };
 		F738F5881E4A3C09005680A2 /* DataWriterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = F738F5861E4A3C09005680A2 /* DataWriterTests.swift */; };
 		F738F58A1E4A3C21005680A2 /* TestUtil.swift in Sources */ = {isa = PBXBuildFile; fileRef = F738F5891E4A3C21005680A2 /* TestUtil.swift */; };
+		F761094D2056FE3F006BB8B0 /* Counter.swift in Sources */ = {isa = PBXBuildFile; fileRef = F761094C2056FE3F006BB8B0 /* Counter.swift */; };
+		F761094F2057198A006BB8B0 /* CounterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = F761094E2057198A006BB8B0 /* CounterTests.swift */; };
+		F761095120572117006BB8B0 /* Mutex.swift in Sources */ = {isa = PBXBuildFile; fileRef = F761095020572117006BB8B0 /* Mutex.swift */; };
 		F7713A5F1F477BA90036A0D5 /* CLI.swift in Sources */ = {isa = PBXBuildFile; fileRef = F7713A5D1F477BA90036A0D5 /* CLI.swift */; };
 		F7713A601F477BA90036A0D5 /* Settings.swift in Sources */ = {isa = PBXBuildFile; fileRef = F7713A5E1F477BA90036A0D5 /* Settings.swift */; };
 		F7ABD9BE1E80603D00768FEC /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = F7ABD9BD1E80603D00768FEC /* Assets.xcassets */; };
@@ -243,6 +246,9 @@
 		F738F5851E4A3C09005680A2 /* DataReaderTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = DataReaderTests.swift; path = DataTests/DataReaderTests.swift; sourceTree = "<group>"; };
 		F738F5861E4A3C09005680A2 /* DataWriterTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = DataWriterTests.swift; path = DataTests/DataWriterTests.swift; sourceTree = "<group>"; };
 		F738F5891E4A3C21005680A2 /* TestUtil.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestUtil.swift; sourceTree = "<group>"; };
+		F761094C2056FE3F006BB8B0 /* Counter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Counter.swift; sourceTree = "<group>"; };
+		F761094E2057198A006BB8B0 /* CounterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CounterTests.swift; sourceTree = "<group>"; };
+		F761095020572117006BB8B0 /* Mutex.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Mutex.swift; sourceTree = "<group>"; };
 		F7713A5D1F477BA90036A0D5 /* CLI.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CLI.swift; sourceTree = "<group>"; };
 		F7713A5E1F477BA90036A0D5 /* Settings.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Settings.swift; sourceTree = "<group>"; };
 		F7ABD9BD1E80603D00768FEC /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
@@ -374,6 +380,8 @@
 				5119862D1E3C1519006A3BBB /* KnownFacets.swift */,
 				514F3D811E43C833008FA513 /* Keychain.swift */,
 				514F3D861E43E828008FA513 /* KeyPair.swift */,
+				F761094C2056FE3F006BB8B0 /* Counter.swift */,
+				F761095020572117006BB8B0 /* Mutex.swift */,
 				51FE30F01E410B3D00BAE824 /* Utils.swift */,
 				51213EC51E3916EB005454E0 /* U2FHID.swift */,
 				51B289E41E39903F00AD90CC /* U2FAuthenticator.swift */,
@@ -390,6 +398,7 @@
 		51F090201E37E8C600F03AD3 /* SoftU2FTests */ = {
 			isa = PBXGroup;
 			children = (
+				F761094E2057198A006BB8B0 /* CounterTests.swift */,
 				51FE30EE1E40F3DB00BAE824 /* U2FRegistrationTests.swift */,
 				51E2145D1E3823E0005B2864 /* SHA256Tests.swift */,
 				51203C381E39234000F661DF /* U2FHIDTests.swift */,
@@ -852,7 +861,9 @@
 				F7713A601F477BA90036A0D5 /* Settings.swift in Sources */,
 				5119862E1E3C1519006A3BBB /* KnownFacets.swift in Sources */,
 				51F090101E37E8C600F03AD3 /* AppDelegate.swift in Sources */,
+				F761095120572117006BB8B0 /* Mutex.swift in Sources */,
 				51213EC61E3916EB005454E0 /* U2FHID.swift in Sources */,
+				F761094D2056FE3F006BB8B0 /* Counter.swift in Sources */,
 				51E214601E3823E7005B2864 /* SHA256.swift in Sources */,
 				51B289E51E39903F00AD90CC /* U2FAuthenticator.swift in Sources */,
 				514F3D821E43C833008FA513 /* Keychain.swift in Sources */,
@@ -867,6 +878,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				F761094F2057198A006BB8B0 /* CounterTests.swift in Sources */,
 				51E214641E382529005B2864 /* WebSafeBase64Tests.swift in Sources */,
 				5131C1B01E3B9C62006A820C /* IntegrationTests.swift in Sources */,
 				51E2145E1E3823E0005B2864 /* SHA256Tests.swift in Sources */,
@@ -1159,7 +1171,7 @@
 				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/inc";
 				INFOPLIST_FILE = SoftU2FToolTests/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				LIBRARY_SEARCH_PATHS = "/usr/local/Cellar/libu2f-host/1.1.3/lib";
+				LIBRARY_SEARCH_PATHS = "/usr/local/Cellar/libu2f-host/1.1.5/lib";
 				PRODUCT_BUNDLE_IDENTIFIER = com.github.SoftU2FToolTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
@@ -1182,7 +1194,7 @@
 				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/inc";
 				INFOPLIST_FILE = SoftU2FToolTests/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				LIBRARY_SEARCH_PATHS = "/usr/local/Cellar/libu2f-host/1.1.3/lib";
+				LIBRARY_SEARCH_PATHS = "/usr/local/Cellar/libu2f-host/1.1.5/lib";
 				PRODUCT_BUNDLE_IDENTIFIER = com.github.SoftU2FToolTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";

SoftU2FTool/CLI.swift

@@ -53,7 +53,6 @@ class CLI {
         print("  - Key handle: This is the key handle that we registered with a website. For Soft U2F, the key handle is simply a hash of the public key.")
         print("  - Application parameter: This is the sha256 of the app-id of the site.")
         print("  - Known facet: For some sites we know the application parameter → site name mapping.")
-        print("  - Counter: How many times this registration has been used.")
         print("  — In SEP: Whether this registration's private key is stored in the SEP.")
         print("")
 
@@ -67,7 +66,6 @@ class CLI {
                 print("Known facet: N/A")
             }
 
-            print("Counter: ", reg.counter)
             print("In SEP: ", reg.inSEP)
             print("")
         }

SoftU2FTool/Counter.swift

@@ -0,0 +1,88 @@
+//
+//  Counter.swift
+//  SoftU2F
+//
+//  Created by Benjamin P Toews on 3/12/18.
+//
+
+import Foundation
+
+class Counter {
+
+    private static let service = "Soft U2F"
+    private static let serviceLen = UInt32(service.utf8.count)
+    private static let account = "counter"
+    private static let accountLen = UInt32(account.utf8.count)
+    private static let mtx = Mutex()
+
+    static var next: UInt32 {
+        mtx.lock()
+        defer { mtx.unlock() }
+
+        let c = current ?? 0
+        current = c + 1
+        return c
+    }
+
+    // assumes mtx is already locked
+    static var current: UInt32? {
+        get {
+            var valLen: UInt32 = 0
+            var val: UnsafeMutableRawPointer? = nil
+
+            let err = SecKeychainFindGenericPassword(nil, serviceLen, service, accountLen, account, &valLen, &val, nil)
+            if err != errSecSuccess {
+                if err != errSecItemNotFound {
+                    print("Error from keychain: \(err)")
+                }
+                return nil
+            }
+            if val == nil { return nil }
+            defer { SecKeychainItemFreeContent(nil, val) }
+
+            guard let strVal = NSString(bytes: val!, length: Int(valLen), encoding: String.Encoding.utf8.rawValue) as String? else {
+                return nil
+            }
+
+            return UInt32(strVal)
+        }
+
+        set {
+            let err: OSStatus
+            if let val: UInt32 = newValue {
+                let strVal = String(val)
+                let strValLen = UInt32(strVal.utf8.count)
+                if let it = item {
+                    err = SecKeychainItemModifyContent(it, nil, strValLen, strVal)
+                } else {
+                    err = SecKeychainAddGenericPassword(nil, serviceLen, service, accountLen, account, strValLen, strVal, nil)
+                }
+            } else {
+                if let it = item {
+                    err = SecKeychainItemDelete(it)
+                } else {
+                    return
+                }
+            }
+
+            if err != errSecSuccess {
+                print("Error from keychain: \(err)")
+            }
+        }
+    }
+
+    // assumes mtx is already locked
+    private static var item: SecKeychainItem? {
+        var it: SecKeychainItem? = nil
+
+        let err = SecKeychainFindGenericPassword(nil, serviceLen, service, accountLen, account, nil, nil, &it)
+        if err != errSecSuccess {
+            if err != errSecItemNotFound {
+                print("Error from keychain: \(err)")
+            }
+            return nil
+        }
+
+        return it
+    }
+}

SoftU2FTool/KnownFacets.swift

@@ -16,5 +16,9 @@ let KnownFacets: [Data: String] = [
     SHA256.digest("https://keepersecurity.com"): "https://keepersecurity.com",
     SHA256.digest("https://api-9dcf9b83.duosecurity.com"): "https://api-9dcf9b83.duosecurity.com",
     SHA256.digest("https://dashboard.stripe.com"): "https://dashboard.stripe.com",
-    SHA256.digest("https://id.fedoraproject.org/u2f-origins.json"): "https://id.fedoraproject.org"
+    SHA256.digest("https://id.fedoraproject.org/u2f-origins.json"): "https://id.fedoraproject.org",
+
+    // When we return an error during authentication, Chrome will send a registration request with
+    // a bogus AppID.
+    "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA".data(using: .ascii)!: "bogus"
 ]

SoftU2FTool/Mutex.swift

@@ -0,0 +1,21 @@
+//
+//  Mutex.swift
+//  SoftU2F
+//
+//  Created by Benjamin P Toews on 3/12/18.
+//  Copyright © 2018 GitHub. All rights reserved.
+//
+
+import Foundation
+
+class Mutex {
+    private var semaphore = DispatchSemaphore(value: 1)
+
+    func lock() {
+        semaphore.wait()
+    }
+
+    func unlock() {
+        semaphore.signal()
+    }
+}

SoftU2FTool/U2FAuthenticator.swift

@@ -98,6 +98,14 @@ class U2FAuthenticator {
         let req = try APDU.RegisterRequest(raw: raw)
 
         let facet = KnownFacets[req.applicationParameter]
+
+        // When we return an error during authentication, Chrome will send a registration request with
+        // a bogus AppID.
+        if facet == "bogus" {
+            self.sendError(status: .OtherError, cid: cid)
+            return
+        }
+
         let notification = UserPresence.Notification.Register(facet: facet)
 
         UserPresence.test(notification) { tupSuccess in
@@ -155,7 +163,7 @@ class U2FAuthenticator {
 
         if reg.inSEP && !laptopIsOpen {
             // Can't use SEP/TouchID if laptop is closed.
-            sendError(status: .OtherError, cid: cid)
+            sendError(status: .ConditionsNotSatisfied, cid: cid)
             return
         }
 
@@ -169,8 +177,8 @@ class U2FAuthenticator {
                 return
             }
 
-            let counter = reg.counter
-            var ctrBigEndian = counter.bigEndian
+            let ctr = Counter.next
+            var ctrBigEndian = ctr.bigEndian
 
             let payloadSize = req.applicationParameter.count + 1 + MemoryLayout<UInt32>.size + req.challengeParameter.count
             var sigPayload = Data(capacity: payloadSize)
@@ -185,7 +193,7 @@ class U2FAuthenticator {
                 return
             }
 
-            let resp = AuthenticationResponse(userPresence: 0x01, counter: counter, signature: sig)
+            let resp = AuthenticationResponse(userPresence: 0x01, counter: ctr, signature: sig)
             self.sendMsg(msg: resp, cid: cid)
             return
         }