12 files changed, 140 insertions, 110 deletions

diff --git a/src/lib/libcrypto/bn/bn_div.c b/src/lib/libcrypto/bn/bn_div.c
index f4deccf77f..fefc53f9fa 100644
--- a/src/lib/libcrypto/bn/bn_div.c
+++ b/src/lib/libcrypto/bn/bn_div.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_div.c,v 1.22 2014/07/11 08:44:47 jsing Exp $ */
+/* $OpenBSD: bn_div.c,v 1.23 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -170,7 +170,7 @@ BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
                 res = BN_CTX_get(ctx);
         else
                 res = dv;
-        if (sdiv == NULL || res == NULL || tmp == NULL || snum == NULL)
+        if (tmp == NULL || snum == NULL || sdiv == NULL || res == NULL)
                 goto err;
 
         /* First we normalise the numbers */
diff --git a/src/lib/libcrypto/bn/bn_exp.c b/src/lib/libcrypto/bn/bn_exp.c
index 1aa5503dae..eecab5163b 100644
--- a/src/lib/libcrypto/bn/bn_exp.c
+++ b/src/lib/libcrypto/bn/bn_exp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_exp.c,v 1.19 2014/07/11 15:01:49 miod Exp $ */
+/* $OpenBSD: bn_exp.c,v 1.20 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -272,9 +272,9 @@ BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
         }
 
         BN_CTX_start(ctx);
-        aa = BN_CTX_get(ctx);
-        val[0] = BN_CTX_get(ctx);
-        if (!aa || !val[0])
+        if ((aa = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((val[0] = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         BN_RECP_CTX_init(&recp);
@@ -408,10 +408,11 @@ BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
         }
 
         BN_CTX_start(ctx);
-        d = BN_CTX_get(ctx);
-        r = BN_CTX_get(ctx);
-        val[0] = BN_CTX_get(ctx);
-        if (!d || !r || !val[0])
+        if ((d = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((r = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((val[0] = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         /* If this is not done, things will break in the montgomery
@@ -885,10 +886,11 @@ BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, const BIGNUM *m,
         }
 
         BN_CTX_start(ctx);
-        d = BN_CTX_get(ctx);
-        r = BN_CTX_get(ctx);
-        t = BN_CTX_get(ctx);
-        if (d == NULL || r == NULL || t == NULL)
+        if ((d = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((r = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((t = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (in_mont != NULL)
@@ -1003,9 +1005,9 @@ BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,
         }
 
         BN_CTX_start(ctx);
-        d = BN_CTX_get(ctx);
-        val[0] = BN_CTX_get(ctx);
-        if (!d || !val[0])
+        if ((d = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((val[0] = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (!BN_nnmod(val[0],a,m,ctx))
diff --git a/src/lib/libcrypto/bn/bn_exp2.c b/src/lib/libcrypto/bn/bn_exp2.c
index c8f0294f7a..38bf467a38 100644
--- a/src/lib/libcrypto/bn/bn_exp2.c
+++ b/src/lib/libcrypto/bn/bn_exp2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_exp2.c,v 1.9 2014/07/11 08:44:47 jsing Exp $ */
+/* $OpenBSD: bn_exp2.c,v 1.10 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -150,11 +150,13 @@ BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
         bits = (bits1 > bits2) ? bits1 : bits2;
 
         BN_CTX_start(ctx);
-        d = BN_CTX_get(ctx);
-        r = BN_CTX_get(ctx);
-        val1[0] = BN_CTX_get(ctx);
-        val2[0] = BN_CTX_get(ctx);
-        if (!d || !r || !val1[0] || !val2[0])
+        if ((d = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((r = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((val1[0] = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((val2[0] = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (in_mont != NULL)
diff --git a/src/lib/libcrypto/bn/bn_gcd.c b/src/lib/libcrypto/bn/bn_gcd.c
index 379bea99ad..da9c29a8e5 100644
--- a/src/lib/libcrypto/bn/bn_gcd.c
+++ b/src/lib/libcrypto/bn/bn_gcd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_gcd.c,v 1.9 2014/07/11 08:44:47 jsing Exp $ */
+/* $OpenBSD: bn_gcd.c,v 1.10 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -125,9 +125,9 @@ BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx)
         bn_check_top(in_b);
 
         BN_CTX_start(ctx);
-        a = BN_CTX_get(ctx);
-        b = BN_CTX_get(ctx);
-        if (a == NULL || b == NULL)
+        if ((a = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((b = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (BN_copy(a, in_a) == NULL)
@@ -247,14 +247,19 @@ BN_mod_inverse(BIGNUM *in, const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
         bn_check_top(n);
 
         BN_CTX_start(ctx);
-        A = BN_CTX_get(ctx);
-        B = BN_CTX_get(ctx);
-        X = BN_CTX_get(ctx);
-        D = BN_CTX_get(ctx);
-        M = BN_CTX_get(ctx);
-        Y = BN_CTX_get(ctx);
-        T = BN_CTX_get(ctx);
-        if (T == NULL)
+        if ((A = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((B = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((X = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((D = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((M = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((Y = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((T = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (in == NULL)
@@ -537,14 +542,19 @@ BN_mod_inverse_no_branch(BIGNUM *in, const BIGNUM *a, const BIGNUM *n,
         bn_check_top(n);
 
         BN_CTX_start(ctx);
-        A = BN_CTX_get(ctx);
-        B = BN_CTX_get(ctx);
-        X = BN_CTX_get(ctx);
-        D = BN_CTX_get(ctx);
-        M = BN_CTX_get(ctx);
-        Y = BN_CTX_get(ctx);
-        T = BN_CTX_get(ctx);
-        if (T == NULL)
+        if ((A = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((B = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((X = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((D = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((M = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((Y = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((T = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (in == NULL)
diff --git a/src/lib/libcrypto/bn/bn_gf2m.c b/src/lib/libcrypto/bn/bn_gf2m.c
index 1cd38c7797..4544369248 100644
--- a/src/lib/libcrypto/bn/bn_gf2m.c
+++ b/src/lib/libcrypto/bn/bn_gf2m.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_gf2m.c,v 1.16 2014/10/28 07:35:58 jsg Exp $ */
+/* $OpenBSD: bn_gf2m.c,v 1.17 2015/02/09 15:49:22 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -840,8 +840,7 @@ BN_GF2m_mod_div(BIGNUM *r, const BIGNUM *y, const BIGNUM *x, const BIGNUM *p,
         bn_check_top(p);
 
         BN_CTX_start(ctx);
-        xinv = BN_CTX_get(ctx);
-        if (xinv == NULL)
+        if ((xinv = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (!BN_GF2m_mod_inv(xinv, x, p, ctx))
@@ -875,11 +874,13 @@ BN_GF2m_mod_div(BIGNUM *r, const BIGNUM *y, const BIGNUM *x, const BIGNUM *p,
 
         BN_CTX_start(ctx);
 
-        a = BN_CTX_get(ctx);
-        b = BN_CTX_get(ctx);
-        u = BN_CTX_get(ctx);
-        v = BN_CTX_get(ctx);
-        if (v == NULL)
+        if ((a = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((b = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((u = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((v = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         /* reduce x and y mod p */
@@ -1137,10 +1138,11 @@ BN_GF2m_mod_solve_quad_arr(BIGNUM *r, const BIGNUM *a_, const int p[],
         }
 
         BN_CTX_start(ctx);
-        a = BN_CTX_get(ctx);
-        z = BN_CTX_get(ctx);
-        w = BN_CTX_get(ctx);
-        if (w == NULL)
+        if ((a = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((z = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((w = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (!BN_GF2m_mod_arr(a, a_, p))
@@ -1169,10 +1171,11 @@ BN_GF2m_mod_solve_quad_arr(BIGNUM *r, const BIGNUM *a_, const int p[],
         }
         else /* m is even */
         {
-                rho = BN_CTX_get(ctx);
-                w2 = BN_CTX_get(ctx);
-                tmp = BN_CTX_get(ctx);
-                if (tmp == NULL)
+                if ((rho = BN_CTX_get(ctx)) == NULL)
+                        goto err;
+                if ((w2 = BN_CTX_get(ctx)) == NULL)
+                        goto err;
+                if ((tmp = BN_CTX_get(ctx)) == NULL)
                         goto err;
                 do {
                         if (!BN_rand(rho, p[0], 0, 0))
diff --git a/src/lib/libcrypto/bn/bn_kron.c b/src/lib/libcrypto/bn/bn_kron.c
index 699cda55f0..274da5d186 100644
--- a/src/lib/libcrypto/bn/bn_kron.c
+++ b/src/lib/libcrypto/bn/bn_kron.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_kron.c,v 1.5 2014/07/11 08:44:48 jsing Exp $ */
+/* $OpenBSD: bn_kron.c,v 1.6 2015/02/09 15:49:22 jsing Exp $ */
 /* ====================================================================
  * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
  *
@@ -79,9 +79,9 @@ BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
         bn_check_top(b);
 
         BN_CTX_start(ctx);
-        A = BN_CTX_get(ctx);
-        B = BN_CTX_get(ctx);
-        if (B == NULL)
+        if ((A = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((B = BN_CTX_get(ctx)) == NULL)
                 goto end;
 
         err = !BN_copy(A, a);
diff --git a/src/lib/libcrypto/bn/bn_mont.c b/src/lib/libcrypto/bn/bn_mont.c
index 5803ca493d..3eb9913a9e 100644
--- a/src/lib/libcrypto/bn/bn_mont.c
+++ b/src/lib/libcrypto/bn/bn_mont.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_mont.c,v 1.23 2014/07/11 08:44:48 jsing Exp $ */
+/* $OpenBSD: bn_mont.c,v 1.24 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -149,8 +149,7 @@ BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
 #endif
 
         BN_CTX_start(ctx);
-        tmp = BN_CTX_get(ctx);
-        if (tmp == NULL)
+        if ((tmp = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         bn_check_top(tmp);
@@ -288,9 +287,9 @@ BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx)
         BIGNUM *t1, *t2;
 
         BN_CTX_start(ctx);
-        t1 = BN_CTX_get(ctx);
-        t2 = BN_CTX_get(ctx);
-        if (t1 == NULL || t2 == NULL)
+        if ((t1 = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((t2 = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (!BN_copy(t1, a))
diff --git a/src/lib/libcrypto/bn/bn_mul.c b/src/lib/libcrypto/bn/bn_mul.c
index daba02d6ca..7794d59707 100644
--- a/src/lib/libcrypto/bn/bn_mul.c
+++ b/src/lib/libcrypto/bn/bn_mul.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_mul.c,v 1.19 2014/07/11 08:44:48 jsing Exp $ */
+/* $OpenBSD: bn_mul.c,v 1.20 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1012,8 +1012,7 @@ BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
                         j = 1 << (j - 1);
                         assert(j <= al || j <= bl);
                         k = j + j;
-                        t = BN_CTX_get(ctx);
-                        if (t == NULL)
+                        if ((t = BN_CTX_get(ctx)) == NULL)
                                 goto err;
                         if (al > j || bl > j) {
                                 if (bn_wexpand(t, k * 4) == NULL)
@@ -1057,7 +1056,8 @@ BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
                         j = BN_num_bits_word((BN_ULONG)al);
                         j = 1 << (j - 1);
                         k = j + j;
-                        t = BN_CTX_get(ctx);
+                        if ((t = BN_CTX_get(ctx)) == NULL)
+                                goto err;
                         if (al == j) /* exact multiple */
                         {
                                 if (bn_wexpand(t, k * 2) == NULL)
diff --git a/src/lib/libcrypto/bn/bn_prime.c b/src/lib/libcrypto/bn/bn_prime.c
index e5cd315e47..02780d32e6 100644
--- a/src/lib/libcrypto/bn/bn_prime.c
+++ b/src/lib/libcrypto/bn/bn_prime.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_prime.c,v 1.12 2014/10/18 17:20:40 jsing Exp $ */
+/* $OpenBSD: bn_prime.c,v 1.13 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -170,8 +170,7 @@ BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, const BIGNUM *add,
         if (ctx == NULL)
                 goto err;
         BN_CTX_start(ctx);
-        t = BN_CTX_get(ctx);
-        if (!t)
+        if ((t = BN_CTX_get(ctx)) == NULL)
                 goto err;
 loop:
         /* make a random number and set the top and bottom bits */
@@ -287,10 +286,11 @@ BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,
                 A = t;
         } else
                 A = a;
-        A1 = BN_CTX_get(ctx);
-        A1_odd = BN_CTX_get(ctx);
-        check = BN_CTX_get(ctx);
-        if (check == NULL)
+        if ((A1 = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((A1_odd = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((check = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         /* compute A1 := A - 1 */
@@ -461,10 +461,11 @@ probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
 
         bits--;
         BN_CTX_start(ctx);
-        t1 = BN_CTX_get(ctx);
-        q = BN_CTX_get(ctx);
-        qadd = BN_CTX_get(ctx);
-        if (qadd == NULL)
+        if ((t1 = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((q = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((qadd = BN_CTX_get(ctx)) == NULL)
                 goto err;
 
         if (!BN_rshift1(qadd, padd))
diff --git a/src/lib/libcrypto/bn/bn_sqr.c b/src/lib/libcrypto/bn/bn_sqr.c
index 5ea9fb083d..a0dce6ea81 100644
--- a/src/lib/libcrypto/bn/bn_sqr.c
+++ b/src/lib/libcrypto/bn/bn_sqr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_sqr.c,v 1.11 2014/07/11 13:26:31 miod Exp $ */
+/* $OpenBSD: bn_sqr.c,v 1.12 2015/02/09 15:49:22 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -85,7 +85,7 @@ BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
         BN_CTX_start(ctx);
         rr = (a != r) ? r : BN_CTX_get(ctx);
         tmp = BN_CTX_get(ctx);
-        if (!rr || !tmp)
+        if (rr == NULL || tmp == NULL)
                 goto err;
 
         max = 2 * al; /* Non-zero (from above) */
diff --git a/src/lib/libcrypto/bn/bn_sqrt.c b/src/lib/libcrypto/bn/bn_sqrt.c
index 9a59d56b3f..f94fa41094 100644
--- a/src/lib/libcrypto/bn/bn_sqrt.c
+++ b/src/lib/libcrypto/bn/bn_sqrt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_sqrt.c,v 1.5 2014/07/11 08:44:48 jsing Exp $ */
+/* $OpenBSD: bn_sqrt.c,v 1.6 2015/02/09 15:49:22 jsing Exp $ */
 /* Written by Lenka Fibikova <fibikova@exp-math.uni-essen.de>
  * and Bodo Moeller for the OpenSSL project. */
 /* ====================================================================
@@ -108,13 +108,17 @@ BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
         }
 
         BN_CTX_start(ctx);
-        A = BN_CTX_get(ctx);
-        b = BN_CTX_get(ctx);
-        q = BN_CTX_get(ctx);
-        t = BN_CTX_get(ctx);
-        x = BN_CTX_get(ctx);
-        y = BN_CTX_get(ctx);
-        if (y == NULL)
+        if ((A = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((b = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((q = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((t = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((x = BN_CTX_get(ctx)) == NULL)
+                goto end;
+        if ((y = BN_CTX_get(ctx)) == NULL)
                 goto end;
 
         if (ret == NULL)
diff --git a/src/lib/libcrypto/bn/bn_x931p.c b/src/lib/libcrypto/bn/bn_x931p.c
index fc8d4c3c49..89c86c1ff7 100644
--- a/src/lib/libcrypto/bn/bn_x931p.c
+++ b/src/lib/libcrypto/bn/bn_x931p.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_x931p.c,v 1.5 2014/06/12 15:49:28 deraadt Exp $ */
+/* $OpenBSD: bn_x931p.c,v 1.6 2015/02/09 15:49:22 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2005.
  */
@@ -107,17 +107,21 @@ BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2, const BIGNUM *Xp,
                 return 0;
 
         BN_CTX_start(ctx);
-        if (!p1)
-                p1 = BN_CTX_get(ctx);
-
-        if (!p2)
-                p2 = BN_CTX_get(ctx);
-
-        t = BN_CTX_get(ctx);
-
-        p1p2 = BN_CTX_get(ctx);
+        if (p1 != NULL) {
+                if ((p1 = BN_CTX_get(ctx)) == NULL)
+                        goto err;
+        }
+        if (p2 != NULL) {
+                if ((p2 = BN_CTX_get(ctx)) == NULL)
+                        goto err;
+        }
 
-        pm1 = BN_CTX_get(ctx);
+        if ((t = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((p1p2 = BN_CTX_get(ctx)) == NULL)
+                goto err;
+        if ((pm1 = BN_CTX_get(ctx)) == NULL)
+                goto err;
 
         if (!bn_x931_derive_pi(p1, Xp1, ctx, cb))
                 goto err;
@@ -213,7 +217,8 @@ BN_X931_generate_Xpq(BIGNUM *Xp, BIGNUM *Xq, int nbits, BN_CTX *ctx)
                 return 0;
 
         BN_CTX_start(ctx);
-        t = BN_CTX_get(ctx);
+        if ((t = BN_CTX_get(ctx)) == NULL)
+                return 0;
 
         for (i = 0; i < 1000; i++) {
                 if (!BN_rand(Xq, nbits, 1, 0))
@@ -247,10 +252,14 @@ BN_X931_generate_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2, BIGNUM *Xp1,
         int ret = 0;
 
         BN_CTX_start(ctx);
-        if (!Xp1)
-                Xp1 = BN_CTX_get(ctx);
-        if (!Xp2)
-                Xp2 = BN_CTX_get(ctx);
+        if (Xp1 != NULL) {
+                if ((Xp1 = BN_CTX_get(ctx)) == NULL)
+                        goto error;
+        }
+        if (Xp2 != NULL) {
+                if ((Xp2 = BN_CTX_get(ctx)) == NULL)
+                        goto error;
+        }
 
         if (!BN_rand(Xp1, 101, 0, 0))
                 goto error;