Merge pull request #600 from RUB-NDS/nullpointerfix

fixed nullpointer exception when pms is null

Author: ic0ns

Attacks/src/main/java/de/rub/nds/tlsattacker/attacks/impl/InvalidCurveAttacker.java

@@ -117,8 +117,9 @@ private void setPremasterSecret(EllipticCurve curve, int i, Point point) {
             premasterSecret = config.getPremasterSecret();
         } else {
             Point sharedPoint = curve.mult(new BigInteger("" + (i + 1)), point);
-            premasterSecret = sharedPoint.getX().getData();
-            if (premasterSecret == null) {
+            if (sharedPoint.getX() != null) {
+                premasterSecret = sharedPoint.getX().getData();
+            } else {
                 premasterSecret = BigInteger.ZERO;
             }
             LOGGER.debug("PMS: " + premasterSecret.toString());

TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/crypto/ec/EllipticCurve.java

@@ -15,6 +15,7 @@
  * fields.
  */
 public abstract class EllipticCurve {
+
     private Point basePoint;
     private BigInteger basePointOrder;
     /**
@@ -26,7 +27,7 @@ public abstract class EllipticCurve {
      * Every child class must define its own public constructor. These
      * constructors must be able to set the coefficients for the curve. They can
      * use this constructor to set the value of modulus.
-     * 
+     *
      * @param modulus
      *            The modulus of the field over which the curve is defined.
      */
@@ -39,7 +40,7 @@ protected EllipticCurve(BigInteger modulus) {
      * constructors must be able to set the coefficients for the curve. They can
      * use this constructor to set the values of modulus, basePoint and
      * basePointOrder.
-     * 
+     *
      * @param modulus
      *            The modulus of the field over which the curve is defined.
      * @param basePointX
@@ -60,7 +61,7 @@ protected EllipticCurve(BigInteger modulus, BigInteger basePointX, BigInteger ba
      * result will be null. If one point is not on the curve and the
      * calculations would require dividing by 0, the result will be the point at
      * infinity.
-     * 
+     *
      * @param p
      *            A point which's coordinates are elements of the field over
      *            which the curve is defined or the point at infinity.
@@ -69,83 +70,70 @@ protected EllipticCurve(BigInteger modulus, BigInteger basePointX, BigInteger ba
      *            which the curve is defined or the point at infinity.
      */
     public Point add(Point p, Point q) {
+        if (p.isAtInfinity()) {
+            // O + q == q
+            return q;
+        }
 
-        if (p == null || q == null) {
-            return null;
-        } else {
-            if (p.isAtInfinity()) {
-                // O + q == q
-                return q;
-            }
-
-            if (q.isAtInfinity()) {
-                // p + O == p
-                return p;
-            }
-
-            if (this.inverse(p).equals(q)) {
-                // p == -q <=> -p == q
-                // => p + q = O
-                return new Point();
-            }
+        if (q.isAtInfinity()) {
+            // p + O == p
+            return p;
+        }
 
-            return this.additionFormular(p, q);
+        if (this.inverse(p).equals(q)) {
+            // p == -q <=> -p == q
+            // => p + q = O
+            return new Point();
         }
+
+        return this.additionFormular(p, q);
     }
 
     /**
      * Returns k*p on this curve. If k or p is null, the result will be null. If
      * the point is not on the curve and the calculations would require dividing
      * by 0, the result will be the point at infinity.
-     * 
+     *
      * @param p
      *            A point which's coordinates are elements of the field over
      *            which the curve is defined or the point at infinity.
      */
     public Point mult(BigInteger k, Point p) {
-        if (k == null || p == null) {
-            return null;
-        } else {
-            if (k.compareTo(BigInteger.ZERO) < 0) {
-                k = k.negate();
-                p = this.inverse(p);
-            }
-
-            // Double-and-add
+        if (k.compareTo(BigInteger.ZERO) < 0) {
+            k = k.negate();
+            p = this.inverse(p);
+        }
 
-            Point q = new Point(); // q == O
+        // Double-and-add
+        Point q = new Point(); // q == O
 
-            for (int i = k.bitLength(); i > 0; i--) {
+        for (int i = k.bitLength(); i > 0; i--) {
 
-                q = this.add(q, q);
+            q = this.add(q, q);
 
-                if (k.testBit(i - 1)) {
-                    q = this.add(q, p);
-                }
+            if (k.testBit(i - 1)) {
+                q = this.add(q, p);
             }
-
-            return q;
         }
+
+        return q;
     }
 
     /**
      * Returns the unique point q with the property p + q = O on this curve. If
      * p is null the result will be null.
-     * 
+     *
      * @param p
      *            A point which's coordinates are elements of the field over
      *            which the curve is defined or the point at infinity.
      */
     public Point inverse(Point p) {
-        if (p == null) {
-            return null;
+
+        if (p.isAtInfinity()) {
+            // -O == O
+            return p;
         } else {
-            if (p.isAtInfinity()) {
-                // -O == O
-                return p;
-            } else {
-                return this.inverseAffine(p);
-            }
+            return this.inverseAffine(p);
         }
     }
 
@@ -154,7 +142,7 @@ public Point inverse(Point p) {
      * are elements of the field over which this curve is defined. Whenever
      * possible, this method should be used instead of creating a point via its
      * own constructor.
-     * 
+     *
      * @param x
      *            The x coordinate of the point.
      * @param y
@@ -164,7 +152,7 @@ public Point inverse(Point p) {
 
     /**
      * Returns true iff the point p is on the curve.
-     * 
+     *
      * @param p
      *            An affine point which's coordinates are elements of the field
      *            over which the curve is defined or the point at infinity.
@@ -174,7 +162,7 @@ public Point inverse(Point p) {
     /**
      * Returns the unique (affine) point q with the property p + q = O on this
      * curve.
-     * 
+     *
      * @param p
      *            An affine point which's coordinates are elements of the field
      *            over which the curve is defined.
@@ -185,7 +173,7 @@ public Point inverse(Point p) {
      * Returns p+q for two affine points p and q, with p != -q. If one point is
      * not on the curve and the calculations would require dividing by 0, the
      * result will be the point at infinity.
-     * 
+     *
      * @param p
      *            An affine point which's coordinates are elements of the field
      *            over which the curve is defined.

TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/crypto/ec/EllipticCurveOverF2m.java

@@ -9,6 +9,8 @@
 package de.rub.nds.tlsattacker.core.crypto.ec;
 
 import java.math.BigInteger;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 /**
  * An elliptic curve over a galois field F_{2^m}.<br />
@@ -18,6 +20,8 @@
  */
 public class EllipticCurveOverF2m extends EllipticCurve {
 
+    private final static Logger LOGGER = LogManager.getLogger();
+
     private final FieldElementF2m a;
     private final FieldElementF2m b;
 
@@ -147,7 +151,8 @@ protected Point additionFormular(Point p, Point q) {
 
             return new Point(x3, y3);
         } catch (ArithmeticException e) {
-            return new Point();
+            LOGGER.warn("Encountered an arithmetic exception during addition. Returning point at 0,0");
+            return this.getPoint(BigInteger.ZERO, BigInteger.ZERO);
         }
     }
 

TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/crypto/ec/EllipticCurveOverFp.java

@@ -8,13 +8,18 @@
  */
 package de.rub.nds.tlsattacker.core.crypto.ec;
 
+import de.rub.nds.tlsattacker.core.constants.GOSTCurve;
 import java.math.BigInteger;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 /**
  * An elliptic curve over a galois field F_p, where p is a prime number.
  */
 public class EllipticCurveOverFp extends EllipticCurve {
 
+    private static final Logger LOGGER = LogManager.getLogger();
+
     private final FieldElementFp a;
     private final FieldElementFp b;
 
@@ -132,7 +137,8 @@ protected Point additionFormular(Point p, Point q) {
 
             return new Point(x3, y3);
         } catch (ArithmeticException e) {
-            return new Point();
+            LOGGER.warn("Encountered an arithmetic exception during addition. Returning point at 0,0");
+            return this.getPoint(BigInteger.ZERO, BigInteger.ZERO);
         }
     }