Properly copy salt when creating new instances of signatures

Author: vanitasvitae

pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java

@@ -1032,19 +1032,39 @@ public static PGPSignature join(PGPSignature sig1, PGPSignature sig2)
         }
 
         SignatureSubpacket[] unhashed = (SignatureSubpacket[])merged.toArray(new SignatureSubpacket[0]);
-        return new PGPSignature(
-            new SignaturePacket(
-                sig1.getVersion(),
-                sig1.sigPck.hasNewPacketFormat(),
-                sig1.getSignatureType(),
-                sig1.getKeyID(),
-                sig1.getKeyAlgorithm(),
-                sig1.getHashAlgorithm(),
-                sig1.getHashedSubPackets().packets,
-                unhashed,
-                sig1.getDigestPrefix(),
-                sig1.sigPck.getSignature()
-            )
-        );
+        if (sig1.getVersion() == SignaturePacket.VERSION_6)
+        {
+            return new PGPSignature(
+                new SignaturePacket(
+                    sig1.getVersion(),
+                    sig1.getSignatureType(),
+                    sig1.getKeyID(),
+                    sig1.getKeyAlgorithm(),
+                    sig1.getHashAlgorithm(),
+                    sig1.getHashedSubPackets().packets,
+                    unhashed,
+                    sig1.getDigestPrefix(),
+                    sig1.sigPck.getSignatureBytes(),
+                    sig1.getSalt()
+                )
+            );
+        }
+        else
+        {
+            return new PGPSignature(
+                new SignaturePacket(
+                    sig1.getVersion(),
+                    sig1.sigPck.hasNewPacketFormat(),
+                    sig1.getSignatureType(),
+                    sig1.getKeyID(),
+                    sig1.getKeyAlgorithm(),
+                    sig1.getHashAlgorithm(),
+                    sig1.getHashedSubPackets().packets,
+                    unhashed,
+                    sig1.getDigestPrefix(),
+                    sig1.sigPck.getSignature()
+                )
+            );
+        }
     }
 }