EAP-pwd server: Fix reassembly buffer handling

data->inbuf allocation might fail and if that were to happen, the next
fragment in the exchange could have resulted in NULL pointer
dereference. Unexpected fragment with more bit might also be able to
trigger this. Fix that by explicitly checking for data->inbuf to be
available before using it.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c
index 11bef55e7191b1bc0b6067cea479604165ca6973..38e2af86b4706eb9ecdc34526529120af15bc3b3 100644 (file)
--- a/src/eap_server/eap_server_pwd.c
+++ b/src/eap_server/eap_server_pwd.c
@@ -912,6 +912,12 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
         * the first and all intermediate fragments have the M bit set
         */
        if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
+               if (!data->inbuf) {
+                       wpa_printf(MSG_DEBUG,
+                                  "EAP-pwd: No buffer for reassembly");
+                       eap_pwd_state(data, FAILURE);
+                       return;
+               }
                if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
                        wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
                                   "attack detected! (%d+%d > %d)",
@@ -932,7 +938,7 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
         * last fragment won't have the M bit set (but we're obviously
         * buffering fragments so that's how we know it's the last)
         */
-       if (data->in_frag_pos) {
+       if (data->in_frag_pos && data->inbuf) {
                pos = wpabuf_head_u8(data->inbuf);
                len = data->in_frag_pos;
                wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",