Fixes #1556 - A timing channel in Password.java.

jetty-jaspi/src/main/java/org/eclipse/jetty/security/jaspi/modules/DigestAuthModule.java

@@ -341,7 +341,7 @@ public class DigestAuthModule extends BaseAuthModule
                 byte[] digest = md.digest();
 
                 // check digest
-                return (TypeUtil.toString(digest, 16).equalsIgnoreCase(response));
+                return stringEquals(TypeUtil.toString(digest, 16).toLowerCase(), response == null ? null : response.toLowerCase());
             }
             catch (Exception e)
             {
@@ -356,6 +356,5 @@ public class DigestAuthModule extends BaseAuthModule
         {
             return username + "," + response;
         }
-
     }
 }

jetty-security/src/main/java/org/eclipse/jetty/security/authentication/DigestAuthenticator.java

@@ -401,7 +401,7 @@ public class DigestAuthenticator extends LoginAuthenticator
                 byte[] digest = md.digest();
 
                 // check digest
-                return (TypeUtil.toString(digest, 16).equalsIgnoreCase(response));
+                return stringEquals(TypeUtil.toString(digest, 16).toLowerCase(), response == null ? null : response.toLowerCase());
             }
             catch (Exception e)
             {

jetty-util/src/main/java/org/eclipse/jetty/util/security/Credential.java

@@ -71,6 +71,44 @@ public abstract class Credential implements Serializable
         return new Password(credential);
     }
 
+    /**
+     * <p>Utility method that replaces String.equals() to avoid timing attacks.</p>
+     *
+     * @param s1 the first string to compare
+     * @param s2 the second string to compare
+     * @return whether the two strings are equal
+     */
+    protected static boolean stringEquals(String s1, String s2)
+    {
+        if (s1 == s2)
+            return true;
+        if (s1 == null || s2 == null || s1.length() != s2.length())
+            return false;
+        boolean result = false;
+        for (int i = 0; i < s1.length(); i++)
+            result |= s1.charAt(i) == s2.charAt(i);
+        return result;
+    }
+
+    /**
+     * <p>Utility method that replaces Arrays.equals() to avoid timing attacks.</p>
+     *
+     * @param b1 the first byte array to compare
+     * @param b2 the second byte array to compare
+     * @return whether the two byte arrays are equal
+     */
+    protected static boolean byteEquals(byte[] b1, byte[] b2)
+    {
+        if (b1 == b2)
+            return true;
+        if (b1 == null || b2 == null || b1.length != b2.length)
+            return false;
+        boolean result = false;
+        for (int i = 0; i < b1.length; i++)
+            result |= b1[i] == b2[i];
+        return result;
+    }
+
     /**
      * Unix Crypt Credentials
      */
@@ -93,8 +131,7 @@ public abstract class Credential implements Serializable
                 credentials=new String((char[])credentials);
             if (!(credentials instanceof String) && !(credentials instanceof Password)) 
                 LOG.warn("Can't check " + credentials.getClass() + " against CRYPT");
-            String passwd = credentials.toString();
-            return _cooked.equals(UnixCrypt.crypt(passwd, _cooked));
+            return stringEquals(_cooked, UnixCrypt.crypt(credentials.toString(), _cooked));
         }
 
         public static String crypt(String user, String pw)
@@ -143,20 +180,12 @@ public abstract class Credential implements Serializable
                         __md.update(credentials.toString().getBytes(StandardCharsets.ISO_8859_1));
                         digest = __md.digest();
                     }
-                    if (digest == null || digest.length != _digest.length) return false;
-                    boolean digestMismatch = false;
-                    for (int i = 0; i < digest.length; i++)
-                        digestMismatch |= (digest[i] != _digest[i]);
-                    return !digestMismatch;
+                    return byteEquals(_digest, digest);
                 }
                 else if (credentials instanceof MD5)
                 {
                     MD5 md5 = (MD5)credentials;
-                    if (_digest.length != md5._digest.length) return false;
-                    boolean digestMismatch = false;
-                    for (int i = 0; i < _digest.length; i++)
-                        digestMismatch |= (_digest[i] != md5._digest[i]);
-                    return !digestMismatch;
+                    return byteEquals(_digest, md5._digest);
                 }
                 else if (credentials instanceof Credential)
                 {

jetty-util/src/main/java/org/eclipse/jetty/util/security/Password.java

@@ -20,7 +20,6 @@ package org.eclipse.jetty.util.security;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.util.Arrays;
 import java.util.Locale;
 
 import org.eclipse.jetty.util.log.Log;
@@ -96,15 +95,20 @@ public class Password extends Credential
     @Override
     public boolean check(Object credentials)
     {
-        if (this == credentials) return true;
+        if (this == credentials)
+            return true;
 
-        if (credentials instanceof Password) return credentials.equals(_pw);
+        if (credentials instanceof Password)
+            return credentials.equals(_pw);
 
-        if (credentials instanceof String) return credentials.equals(_pw);
+        if (credentials instanceof String)
+            return stringEquals(_pw, (String)credentials);
 
-        if (credentials instanceof char[]) return Arrays.equals(_pw.toCharArray(), (char[]) credentials);
+        if (credentials instanceof char[])
+            return stringEquals(_pw, new String((char[])credentials));
 
-        if (credentials instanceof Credential) return ((Credential) credentials).check(_pw);
+        if (credentials instanceof Credential)
+            return ((Credential)credentials).check(_pw);
 
         return false;
     }
@@ -120,14 +124,10 @@ public class Password extends Credential
             return false;
 
         if (o instanceof Password)
-        {
-            Password p = (Password) o;
-            //noinspection StringEquality
-            return p._pw == _pw || (null != _pw && _pw.equals(p._pw));
-        }
+            return stringEquals(_pw, ((Password)o)._pw);
 
         if (o instanceof String)
-            return o.equals(_pw);
+            return stringEquals(_pw, (String)o);
 
         return false;
     }
@@ -175,7 +175,6 @@ public class Password extends Credential
 
         }
         return buf.toString();
-
     }
 
     /* ------------------------------------------------------------ */