diff --git a/apps/dsaparam.c b/apps/dsaparam.c
index 63e2cab45f..7a3110136c 100644
--- a/apps/dsaparam.c
+++ b/apps/dsaparam.c
@@ -281,10 +281,7 @@ bad:
 	if (numbits > 0)
 		{
 		BN_GENCB cb;
-		cb.ver = 2;
-		cb.cb_2 = dsa_cb;
-		cb.arg = bio_err;
-
+		BN_GENCB_set(&cb, dsa_cb, bio_err);
 		assert(need_rand);
 		dsa = DSA_new();
 		if(!dsa)
diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index c1b5b41935..58263baf9a 100644
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -299,10 +299,22 @@ struct bn_gencb_st
 		void (*cb_1)(int, int, void *);
 		/* if(ver==2) - new callback style */
 		int (*cb_2)(int, int, BN_GENCB *);
-		};
+		} cb;
 	};
 /* Wrapper function to make using BN_GENCB easier,  */
 int BN_GENCB_call(BN_GENCB *cb, int a, int b);
+/* Macro to populate a BN_GENCB structure with an "old"-style callback */
+#define BN_GENCB_set_old(gencb, callback, cb_arg) { \
+		BN_GENCB *tmp_gencb = (gencb); \
+		tmp_gencb->ver = 1; \
+		tmp_gencb->arg = (cb_arg); \
+		tmp_gencb->cb.cb_1 = (callback); }
+/* Macro to populate a BN_GENCB structure with a "new"-style callback */
+#define BN_GENCB_set(gencb, callback, cb_arg) { \
+		BN_GENCB *tmp_gencb = (gencb); \
+		tmp_gencb->ver = 2; \
+		tmp_gencb->arg = (cb_arg); \
+		tmp_gencb->cb.cb_2 = (callback); }
 
 #define BN_prime_checks 0 /* default: select number of iterations
 			     based on the size of the number */
diff --git a/crypto/bn/bn_depr.c b/crypto/bn/bn_depr.c
index 76c349833c..35e9127288 100644
--- a/crypto/bn/bn_depr.c
+++ b/crypto/bn/bn_depr.c
@@ -70,9 +70,7 @@ BIGNUM *BN_generate_prime(BIGNUM *ret, int bits, int safe,
 	BIGNUM *rnd=NULL;
 	int found = 0;
 
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 
 	if (ret == NULL)
 		{
@@ -94,9 +92,7 @@ int BN_is_prime(const BIGNUM *a, int checks, void (*callback)(int,int,void *),
 	BN_CTX *ctx_passed, void *cb_arg)
 	{
 	BN_GENCB cb;
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 	return BN_is_prime_ex(a, checks, ctx_passed, &cb);
 	}
 
@@ -106,9 +102,7 @@ int BN_is_prime_fasttest(const BIGNUM *a, int checks,
 		int do_trial_division)
 	{
 	BN_GENCB cb;
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 	return BN_is_prime_fasttest_ex(a, checks, ctx_passed,
 				do_trial_division, &cb);
 	}
diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c
index a9ec01d916..43eb9e6dfd 100644
--- a/crypto/bn/bn_prime.c
+++ b/crypto/bn/bn_prime.c
@@ -142,11 +142,11 @@ int BN_GENCB_call(BN_GENCB *cb, int a, int b)
 		{
 	case 1:
 		/* Deprecated-style callbacks */
-		cb->cb_1(a, b, cb->arg);
+		cb->cb.cb_1(a, b, cb->arg);
 		return 1;
 	case 2:
 		/* New-style callbacks */
-		return cb->cb_2(a, b, cb);
+		return cb->cb.cb_2(a, b, cb);
 	default:
 		break;
 		}
diff --git a/crypto/dh/dh_depr.c b/crypto/dh/dh_depr.c
index 8a909b1959..3eb319e2a8 100644
--- a/crypto/dh/dh_depr.c
+++ b/crypto/dh/dh_depr.c
@@ -70,9 +70,7 @@ DH *DH_generate_parameters(int prime_len, int generator,
 	if((ret=DH_new()) == NULL)
 		return NULL;
 
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 
 	if(DH_generate_parameters_ex(ret, prime_len, generator, &cb))
 		return ret;
diff --git a/crypto/dsa/dsa_depr.c b/crypto/dsa/dsa_depr.c
index c16315389b..cb80457211 100644
--- a/crypto/dsa/dsa_depr.c
+++ b/crypto/dsa/dsa_depr.c
@@ -91,9 +91,7 @@ DSA *DSA_generate_parameters(int bits,
 
 	if ((ret=DSA_new()) == NULL) return NULL;
 
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 
 	if(DSA_generate_parameters_ex(ret, bits, seed_in, seed_len,
 				counter_ret, h_ret, &cb))
diff --git a/crypto/rsa/rsa_depr.c b/crypto/rsa/rsa_depr.c
index 25fa954393..3773d037c6 100644
--- a/crypto/rsa/rsa_depr.c
+++ b/crypto/rsa/rsa_depr.c
@@ -71,9 +71,7 @@ RSA *RSA_generate_key(int bits, unsigned long e_value,
 	if((rsa=RSA_new()) == NULL)
 		return 0;
 
-	cb.ver = 1;
-	cb.arg = cb_arg;
-	cb.cb_1 = callback;
+	BN_GENCB_set_old(&cb, callback, cb_arg);
 
 	if(RSA_generate_key_ex(rsa, bits, e_value, &cb))
 		return rsa;
diff --git a/crypto/rsa/rsa_gen.c b/crypto/rsa/rsa_gen.c
index a45b9aab5c..e3ae03e691 100644
--- a/crypto/rsa/rsa_gen.c
+++ b/crypto/rsa/rsa_gen.c
@@ -166,22 +166,16 @@ int RSA_generate_key_ex(RSA *rsa, int bits, unsigned long e_value, BN_GENCB *cb)
 		goto err;
 		}
 */
-	rsa->d=BN_mod_inverse(NULL,rsa->e,r0,ctx2);	/* d */
-	if (rsa->d == NULL) goto err;
+	if (!BN_mod_inverse(rsa->d,rsa->e,r0,ctx2)) goto err;	/* d */
 
 	/* calculate d mod (p-1) */
-	rsa->dmp1=BN_new();
-	if (rsa->dmp1 == NULL) goto err;
 	if (!BN_mod(rsa->dmp1,rsa->d,r1,ctx)) goto err;
 
 	/* calculate d mod (q-1) */
-	rsa->dmq1=BN_new();
-	if (rsa->dmq1 == NULL) goto err;
 	if (!BN_mod(rsa->dmq1,rsa->d,r2,ctx)) goto err;
 
 	/* calculate inverse of q mod p */
-	rsa->iqmp=BN_mod_inverse(NULL,rsa->q,rsa->p,ctx2);
-	if (rsa->iqmp == NULL) goto err;
+	if (!BN_mod_inverse(rsa->iqmp,rsa->q,rsa->p,ctx2)) goto err;
 
 	ok=1;
 err: