1 files changed, 5 insertions, 3 deletions

diff --git a/src/lib/libcrypto/bn/bn_kron.c b/src/lib/libcrypto/bn/bn_kron.c
index 49f75594ae..740359b752 100644
--- a/src/lib/libcrypto/bn/bn_kron.c
+++ b/src/lib/libcrypto/bn/bn_kron.c
@@ -53,9 +53,9 @@
  *
  */
 
+#include "cryptlib.h"
 #include "bn_lcl.h"
 
-
 /* least significant word */
 #define BN_lsw(n) (((n)->top == 0) ? (BN_ULONG) 0 : (n)->d[0])
 
@@ -74,6 +74,9 @@ int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
          */
         static const int tab[8] = {0, 1, 0, -1, 0, -1, 0, 1};
 
+        bn_check_top(a);
+        bn_check_top(b);
+
         BN_CTX_start(ctx);
         A = BN_CTX_get(ctx);
         B = BN_CTX_get(ctx);
@@ -172,8 +175,7 @@ int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
                 tmp = A; A = B; B = tmp;
                 tmp->neg = 0;
                 }
-        
- end:
+end:
         BN_CTX_end(ctx);
         if (err)
                 return -2;