Avoid segfault if ret==0.

Submitted by: Nils Larsch

diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c
index f02e6fcdb422903cff18eaeba6b7ee9313dfe09f..0248753f6dc9a0f1499fb19d092d0c7d5b37b640 100644 (file)
--- a/crypto/bn/bn_gcd.c
+++ b/crypto/bn/bn_gcd.c
@@ -488,6 +488,7 @@ BIGNUM *BN_mod_inverse(BIGNUM *in,
 err:
        if ((ret == NULL) && (in == NULL)) BN_free(R);
        BN_CTX_end(ctx);
-       bn_check_top(ret);
+       if (ret)
+               bn_check_top(ret);
        return(ret);
        }