Add error handling to the remaining calls to bn_wexpand().

Noticed by pascal-cuoq from Github:
https://github.com/libressl-portable/openbsd/issues/56

ok beck@

1 files changed, 7 insertions, 4 deletions

diff --git a/src/lib/libcrypto/bn/bn_gf2m.c b/src/lib/libcrypto/bn/bn_gf2m.c
index 40c1a94220..d83ae291ec 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 1.20 2015/06/11 15:55:28 jsing Exp $ */
+/* $OpenBSD: bn_gf2m.c,v 1.21 2016/03/12 21:44:11 bcook Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -702,18 +702,21 @@ BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
                 top = p->top;
                 BN_ULONG *udp, *bdp, *vdp, *cdp;
 
-                bn_wexpand(u, top);
+                if (!bn_wexpand(u, top))
+                        goto err;
                 udp = u->d;
                 for (i = u->top; i < top; i++)
                         udp[i] = 0;
                 u->top = top;
-                bn_wexpand(b, top);
+                if (!bn_wexpand(b, top))
+                        goto err;
                 bdp = b->d;
                 bdp[0] = 1;
                 for (i = 1; i < top; i++)
                         bdp[i] = 0;
                 b->top = top;
-                bn_wexpand(c, top);
+                if (!bn_wexpand(c, top))
+                        goto err;
                 cdp = c->d;
                 for (i = 0; i < top; i++)
                         cdp[i] = 0;