RADIUS: Use os_memcmp_const() for hash/password comparisons

This makes the implementation less likely to provide useful timing
information to potential attackers from comparisons of information
received from a remote device and private material known only by the
authorized devices.

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

src/radius/radius.c

@@ -508,7 +508,7 @@ int radius_msg_verify_acct_req(struct radius_msg *msg, const u8 *secret,
 	addr[3] = secret;
 	len[3] = secret_len;
 	md5_vector(4, addr, len, hash);
-	return os_memcmp(msg->hdr->authenticator, hash, MD5_MAC_LEN) != 0;
+	return os_memcmp_const(msg->hdr->authenticator, hash, MD5_MAC_LEN) != 0;
 }
 
 
@@ -535,7 +535,7 @@ int radius_msg_verify_das_req(struct radius_msg *msg, const u8 *secret,
 	addr[3] = secret;
 	len[3] = secret_len;
 	md5_vector(4, addr, len, hash);
-	if (os_memcmp(msg->hdr->authenticator, hash, MD5_MAC_LEN) != 0)
+	if (os_memcmp_const(msg->hdr->authenticator, hash, MD5_MAC_LEN) != 0)
 		return 1;
 
 	for (i = 0; i < msg->attr_used; i++) {
@@ -568,7 +568,7 @@ int radius_msg_verify_das_req(struct radius_msg *msg, const u8 *secret,
 	os_memcpy(msg->hdr->authenticator, orig_authenticator,
 		  sizeof(orig_authenticator));
 
-	return os_memcmp(orig, auth, MD5_MAC_LEN) != 0;
+	return os_memcmp_const(orig, auth, MD5_MAC_LEN) != 0;
 }
 
 
@@ -801,7 +801,7 @@ int radius_msg_verify_msg_auth(struct radius_msg *msg, const u8 *secret,
 			  sizeof(orig_authenticator));
 	}
 
-	if (os_memcmp(orig, auth, MD5_MAC_LEN) != 0) {
+	if (os_memcmp_const(orig, auth, MD5_MAC_LEN) != 0) {
 		wpa_printf(MSG_INFO, "Invalid Message-Authenticator!");
 		return 1;
 	}
@@ -838,7 +838,7 @@ int radius_msg_verify(struct radius_msg *msg, const u8 *secret,
 	addr[3] = secret;
 	len[3] = secret_len;
 	md5_vector(4, addr, len, hash);
-	if (os_memcmp(hash, msg->hdr->authenticator, MD5_MAC_LEN) != 0) {
+	if (os_memcmp_const(hash, msg->hdr->authenticator, MD5_MAC_LEN) != 0) {
 		wpa_printf(MSG_INFO, "Response Authenticator invalid!");
 		return 1;
 	}

src/radius/radius_server.c

@@ -864,7 +864,7 @@ radius_server_macacl(struct radius_server_data *data,
 			os_free(tmp.password);
 
 			if (res < 0 || pw_len != (size_t) res ||
-			    os_memcmp(pw, buf, res) != 0) {
+			    os_memcmp_const(pw, buf, res) != 0) {
 				RADIUS_DEBUG("Incorrect User-Password");
 				code = RADIUS_CODE_ACCESS_REJECT;
 			}