Don't call memcpy with NULL as source

Calling it with lenght 0 and NULL as source is undefined behaviour.

Reviewed-by: Rich Salz <rsalz@openssl.org>
GH: #2089

diff --git a/crypto/bn/bn_intern.c b/crypto/bn/bn_intern.c
index 9227b6e2415998a9e619b84eb74337eaaa38700a..2c970647defd5efec7d925c92f8daad61671f748 100644 (file)
--- a/crypto/bn/bn_intern.c
+++ b/crypto/bn/bn_intern.c
@@ -167,7 +167,8 @@ int bn_copy_words(BN_ULONG *out, const BIGNUM *in, int size)
         return 0;
 
     memset(out, 0, sizeof(*out) * size);
-    memcpy(out, in->d, sizeof(*out) * in->top);
+    if (in->d != NULL)
+        memcpy(out, in->d, sizeof(*out) * in->top);
     return 1;
 }