git.librecmc.org Git - oweals/openwrt.git/blob

   1 From 3035cc2894e08319b905bd6561e8bddc8c2db9fa Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Sat, 2 May 2015 19:26:06 +0300
   4 Subject: [PATCH 4/5] EAP-pwd server: Fix Total-Length parsing for fragment
   5  reassembly
   6
   7 The remaining number of bytes in the message could be smaller than the
   8 Total-Length field size, so the length needs to be explicitly checked
   9 prior to reading the field and decrementing the len variable. This could
  10 have resulted in the remaining length becoming negative and interpreted
  11 as a huge positive integer.
  12
  13 In addition, check that there is no already started fragment in progress
  14 before allocating a new buffer for reassembling fragments. This avoid a
  15 potential memory leak when processing invalid message.
  16
  17 Signed-off-by: Jouni Malinen <j@w1.fi>
  18 ---
  19  src/eap_server/eap_server_pwd.c | 10 ++++++++++
  20  1 file changed, 10 insertions(+)
  21
  22 diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c
  23 index 3189105..2bfc3c2 100644
  24 --- a/src/eap_server/eap_server_pwd.c
  25 +++ b/src/eap_server/eap_server_pwd.c
  26 @@ -942,11 +942,21 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
  27          * the first fragment has a total length
  28          */
  29         if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
  30 +               if (len < 2) {
  31 +                       wpa_printf(MSG_DEBUG,
  32 +                                  "EAP-pwd: Frame too short to contain Total-Length field");
  33 +                       return;
  34 +               }
  35                 tot_len = WPA_GET_BE16(pos);
  36                 wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments, total "
  37                            "length = %d", tot_len);
  38                 if (tot_len > 15000)
  39                         return;
  40 +               if (data->inbuf) {
  41 +                       wpa_printf(MSG_DEBUG,
  42 +                                  "EAP-pwd: Unexpected new fragment start when previous fragment is still in use");
  43 +                       return;
  44 +               }
  45                 data->inbuf = wpabuf_alloc(tot_len);
  46                 if (data->inbuf == NULL) {
  47                         wpa_printf(MSG_INFO, "EAP-pwd: Out of memory to "
  48 --
  49 1.9.1
  50