Add check to make sure EAP header length matches expected payload length.

ok markus@ yasuoka@

diff --git a/sbin/iked/ikev2_pld.c b/sbin/iked/ikev2_pld.c
index 1fb5f30..2760503 100644 (file)
--- a/sbin/iked/ikev2_pld.c
+++ b/sbin/iked/ikev2_pld.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ikev2_pld.c,v 1.134 2024/03/02 16:16:07 tobhe Exp $   */
+/*     $OpenBSD: ikev2_pld.c,v 1.135 2024/04/02 19:58:28 tobhe Exp $   */
 
 /*
  * Copyright (c) 2019 Tobias Heider <tobias.heider@stusta.de>
@@ -2074,19 +2074,25 @@ ikev2_pld_eap(struct iked *env, struct ikev2_payload *pld,
        struct eap_header                hdr;
        struct eap_message              *eap = NULL;
        const struct iked_sa            *sa = msg->msg_sa;
-       size_t                           len;
+       size_t                           eap_len;
 
        if (ikev2_validate_eap(msg, offset, left, &hdr))
                return (-1);
-       len = betoh16(hdr.eap_length);
 
-       if (len < sizeof(*eap)) {
+       eap_len = betoh16(hdr.eap_length);
+       if (left != eap_len) {
+               log_info("%s: malformed payload: EAP length does not match"
+                   " payload length (%zu != %zu)", __func__, left, eap_len);
+               return (-1);
+       }
+
+       if (eap_len < sizeof(*eap)) {
                log_info("%s: %s id %d length %d", SPI_SA(sa, __func__),
                    print_map(hdr.eap_code, eap_code_map),
                    hdr.eap_id, betoh16(hdr.eap_length));
        } else {
                /* Now try to get the indicated length */
-               if ((eap = ibuf_seek(msg->msg_data, offset, len)) == NULL) {
+               if ((eap = ibuf_seek(msg->msg_data, offset, eap_len)) == NULL) {
                        log_debug("%s: invalid EAP length", __func__);
                        return (-1);
                }