Add missing return value checks

The function DH_check_pub_key() was missing some return value checks in
some calls to BN functions.

RT#4278

Reviewed-by: Andy Polyakov <appro@openssl.org>

diff --git a/crypto/dh/dh_check.c b/crypto/dh/dh_check.c
index 3f9e90e92453b7f656de0efff8e2e65bfa5feef8..2cc218dbdce06ab4aa5a76c79e2fa257da00bc05 100644 (file)
--- a/crypto/dh/dh_check.c
+++ b/crypto/dh/dh_check.c
@@ -151,13 +151,12 @@ int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
         goto err;
     BN_CTX_start(ctx);
     tmp = BN_CTX_get(ctx);
-    if (tmp == NULL)
+    if (tmp == NULL || !BN_set_word(tmp, 1))
         goto err;
-    BN_set_word(tmp, 1);
     if (BN_cmp(pub_key, tmp) <= 0)
         *ret |= DH_CHECK_PUBKEY_TOO_SMALL;
-    BN_copy(tmp, dh->p);
-    BN_sub_word(tmp, 1);
+    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))
+        goto err;
     if (BN_cmp(pub_key, tmp) >= 0)
         *ret |= DH_CHECK_PUBKEY_TOO_LARGE;