Do not construct out-of-bound pointers in SHA512/SHA1/RIPEMD160 code

src/crypto/sha1.cpp

@@ -163,7 +163,7 @@ CSHA1& CSHA1::Write(const unsigned char* data, size_t len)
         sha1::Transform(s, buf);
         bufsize = 0;
     }
-    while (end >= data + 64) {
+    while (end - data >= 64) {
         // Process full chunks directly from the source.
         sha1::Transform(s, data);
         bytes += 64;