ForceZero - align 64-bit access on Intel 64-bit

Test added to ensure ForceZero works.

wolfcrypt/src/misc.c

@@ -201,7 +201,13 @@ STATIC INLINE void ForceZero(const void* mem, word32 len)
     volatile byte* z = (volatile byte*)mem;
 #if defined(WOLFSSL_X86_64_BUILD) && defined(WORD64_AVAILABLE)
     volatile word64* w;
+    #ifndef WOLFSSL_UNALIGNED_64BIT_ACCESS
+        word32 l = (8 - ((size_t)z & 0x7)) & 0x7;
 
+        if (len < l) l = len;
+        len -= l;
+        while (l--) *z++ = 0;
+    #endif
     for (w = (volatile word64*)z; len >= sizeof(*w); len -= sizeof(*w))
         *w++ = 0;
     z = (volatile byte*)w;

wolfcrypt/test/test.c

@@ -120,6 +120,10 @@
     #include <wolfssl/wolfcrypt/port/caam/wolfcaam.h>
 #endif
 
+#define WOLFSSL_MISC_INCLUDED
+#include <wolfcrypt/src/misc.c>
+
+
 /* only for stack size check */
 #ifdef HAVE_STACK_SIZE
     #include <wolfssl/ssl.h>
@@ -335,6 +339,7 @@ int memcb_test(void);
 #ifdef WOLFSSL_IMX6_CAAM_BLOB
 int blob_test(void);
 #endif
+int misc_test(void);
 
 
 /* General big buffer size for many tests. */
@@ -950,6 +955,11 @@ initDefaultName();
         printf( "blob     test passed!\n");
 #endif
 
+    if ( (ret = misc_test()) != 0)
+        return err_sys("misc     test failed!\n", ret);
+    else
+        printf( "misc     test passed!\n");
+
 #ifdef WOLFSSL_ASYNC_CRYPT
     wolfAsync_DevClose(&devId);
 #endif
@@ -18524,6 +18534,33 @@ int blob_test(void)
 }
 #endif /* WOLFSSL_IMX6_CAAM_BLOB */
 
+int misc_test(void)
+{
+    unsigned char data[32];
+    unsigned int i, j, len;
+
+    /* Test ForceZero */
+    for (i = 0; i < sizeof(data); i++) {
+        for (len = 1; len < sizeof(data) - i; len++) {
+            for (j = 0; j < sizeof(data); j++)
+                data[j] = j + 1;
+
+            ForceZero(data + i, len);
+
+            for (j = 0; j < sizeof(data); j++) {
+                if (j < i || j >= i + len) {
+                    if (data[j] == 0x00)
+                        return -9000;
+                }
+                else if (data[j] != 0x00)
+                    return -9001;
+            }
+        }
+    }
+
+    return 0;
+}
+
 #undef ERROR_OUT
 
 #else