From dcb3429884a153442d5fa92d91f2ce2b3d380f43 Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Wed, 8 Feb 2017 11:13:53 +0000
Subject: [PATCH] Enforce all hmac/mac to always be lower case.

---
 .../java/at/bitfire/davdroid/journalmanager/Helpers.java    | 6 +++++-
 .../davdroid/journalmanager/JournalEntryManager.java        | 2 +-
 .../at/bitfire/davdroid/journalmanager/JournalManager.java  | 3 ++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/app/src/main/java/at/bitfire/davdroid/journalmanager/Helpers.java b/app/src/main/java/at/bitfire/davdroid/journalmanager/Helpers.java
index c25ef7c2..641e0839 100644
--- a/app/src/main/java/at/bitfire/davdroid/journalmanager/Helpers.java
+++ b/app/src/main/java/at/bitfire/davdroid/journalmanager/Helpers.java
@@ -120,9 +120,13 @@ public class Helpers {
         try {
             MessageDigest digest = MessageDigest.getInstance("SHA-256");
             byte[] hash = digest.digest(base);
-            return Hex.toHexString(hash);
+            return toHex(hash);
         } catch (Exception ex) {
             throw new RuntimeException(ex);
         }
     }
+
+    public static String toHex(byte[] bytes) {
+        return Hex.toHexString(bytes).toLowerCase();
+    }
 }
diff --git a/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalEntryManager.java b/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalEntryManager.java
index b5fe6592..aac438b6 100644
--- a/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalEntryManager.java
+++ b/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalEntryManager.java
@@ -105,7 +105,7 @@ public class JournalEntryManager extends BaseManager {
                 uuid = previous.getUuid();
             }
 
-            return Hex.toHexString(calculateHmac(keyBase64, uuid));
+            return Helpers.toHex(calculateHmac(keyBase64, uuid));
         }
     }
 
diff --git a/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalManager.java b/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalManager.java
index bbed9b7e..6d1002f7 100644
--- a/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalManager.java
+++ b/app/src/main/java/at/bitfire/davdroid/journalmanager/JournalManager.java
@@ -19,6 +19,7 @@ import okhttp3.Response;
 import okhttp3.ResponseBody;
 
 import static at.bitfire.davdroid.journalmanager.Helpers.sha256;
+import static at.bitfire.davdroid.journalmanager.Helpers.toHex;
 
 public class JournalManager extends BaseManager {
     final static private Type journalType = new TypeToken<List<Journal>>() {
@@ -104,7 +105,7 @@ public class JournalManager extends BaseManager {
 
             byte[] correctHash = calculateHmac(keyBase64);
             if (!Arrays.areEqual(hmac, correctHash)) {
-                throw new Exceptions.IntegrityException("Bad HMAC. " + Hex.toHexString(hmac) + " != " + Hex.toHexString(correctHash));
+                throw new Exceptions.IntegrityException("Bad HMAC. " + toHex(hmac) + " != " + toHex(correctHash));
             }
         }