MSCHAPv2: Check challenge_hash() failures

In theory, the SHA1 operation may fail (e.g., if SHA1 becomes disallowed
in some security policies), so better check the return code from
challenge_hash().

Signed-hostap: Jouni Malinen <j@w1.fi>

src/crypto/ms_funcs.c

@@ -1,6 +1,6 @@
 /*
  * WPA Supplicant / shared MSCHAPV2 helper functions / RFC 2433 / RFC 2759
- * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
@@ -173,8 +173,9 @@ int generate_nt_response(const u8 *auth_challenge, const u8 *peer_challenge,
 	u8 challenge[8];
 	u8 password_hash[16];
 
-	challenge_hash(peer_challenge, auth_challenge, username, username_len,
-		       challenge);
+	if (challenge_hash(peer_challenge, auth_challenge, username,
+			   username_len, challenge))
+		return -1;
 	if (nt_password_hash(password, password_len, password_hash))
 		return -1;
 	challenge_response(challenge, password_hash, response);
@@ -260,8 +261,9 @@ int generate_authenticator_response_pwhash(
 	if (sha1_vector(3, addr1, len1, response))
 		return -1;
 
-	challenge_hash(peer_challenge, auth_challenge, username, username_len,
-		       challenge);
+	if (challenge_hash(peer_challenge, auth_challenge, username,
+			   username_len, challenge))
+		return -1;
 	return sha1_vector(3, addr2, len2, response);
 }