1 files changed, 9 insertions, 6 deletions

diff --git a/util.h b/util.h
index 9ec701b9e7..bf8cf300fd 100644
--- a/util.h
+++ b/util.h
@@ -430,8 +430,9 @@ inline void heapchk()
 template<typename T1>

 inline uint256 Hash(const T1 pbegin, const T1 pend)

 {

+    static unsigned char pblank[1];

     uint256 hash1;

-    SHA256((unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]), (unsigned char*)&hash1);

+    SHA256((pbegin == pend ? pblank : (unsigned char*)&pbegin[0]), (pend - pbegin) * sizeof(pbegin[0]), (unsigned char*)&hash1);

     uint256 hash2;

     SHA256((unsigned char*)&hash1, sizeof(hash1), (unsigned char*)&hash2);

     return hash2;

@@ -441,11 +442,12 @@ template<typename T1, typename T2>
 inline uint256 Hash(const T1 p1begin, const T1 p1end,

                     const T2 p2begin, const T2 p2end)

 {

+    static unsigned char pblank[1];

     uint256 hash1;

     SHA256_CTX ctx;

     SHA256_Init(&ctx);

-    SHA256_Update(&ctx, (unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]));

-    SHA256_Update(&ctx, (unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]));

+    SHA256_Update(&ctx, (p1begin == p1end ? pblank : (unsigned char*)&p1begin[0]), (p1end - p1begin) * sizeof(p1begin[0]));

+    SHA256_Update(&ctx, (p2begin == p2end ? pblank : (unsigned char*)&p2begin[0]), (p2end - p2begin) * sizeof(p2begin[0]));

     SHA256_Final((unsigned char*)&hash1, &ctx);

     uint256 hash2;

     SHA256((unsigned char*)&hash1, sizeof(hash1), (unsigned char*)&hash2);

@@ -457,12 +459,13 @@ inline uint256 Hash(const T1 p1begin, const T1 p1end,
                     const T2 p2begin, const T2 p2end,

                     const T3 p3begin, const T3 p3end)

 {

+    static unsigned char pblank[1];

     uint256 hash1;

     SHA256_CTX ctx;

     SHA256_Init(&ctx);

-    SHA256_Update(&ctx, (unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]));

-    SHA256_Update(&ctx, (unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]));

-    SHA256_Update(&ctx, (unsigned char*)&p3begin[0], (p3end - p3begin) * sizeof(p3begin[0]));

+    SHA256_Update(&ctx, (p1begin == p1end ? pblank : (unsigned char*)&p1begin[0]), (p1end - p1begin) * sizeof(p1begin[0]));

+    SHA256_Update(&ctx, (p2begin == p2end ? pblank : (unsigned char*)&p2begin[0]), (p2end - p2begin) * sizeof(p2begin[0]));

+    SHA256_Update(&ctx, (p3begin == p3end ? pblank : (unsigned char*)&p3begin[0]), (p3end - p3begin) * sizeof(p3begin[0]));

     SHA256_Final((unsigned char*)&hash1, &ctx);

     uint256 hash2;

     SHA256((unsigned char*)&hash1, sizeof(hash1), (unsigned char*)&hash2);