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

   1 From bef802ece03f9ae9d52a21f0cf4f1bc2c5a1f8aa Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Sun, 1 Nov 2015 18:24:16 +0200
   4 Subject: [PATCH] EAP-pwd server: Fix last fragment length validation
   5
   6 All but the last fragment had their length checked against the remaining
   7 room in the reassembly buffer. This allowed a suitably constructed last
   8 fragment frame to try to add extra data that would go beyond the buffer.
   9 The length validation code in wpabuf_put_data() prevents an actual
  10 buffer write overflow from occurring, but this results in process
  11 termination. (CVE-2015-5314)
  12
  13 Signed-off-by: Jouni Malinen <j@w1.fi>
  14 ---
  15  src/eap_server/eap_server_pwd.c | 6 +++---
  16  1 file changed, 3 insertions(+), 3 deletions(-)
  17
  18 diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c
  19 index cb83ff7..9f787ab 100644
  20 --- a/src/eap_server/eap_server_pwd.c
  21 +++ b/src/eap_server/eap_server_pwd.c
  22 @@ -970,7 +970,7 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
  23         /*
  24          * the first and all intermediate fragments have the M bit set
  25          */
  26 -       if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
  27 +       if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
  28                 if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
  29                         wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
  30                                    "attack detected! (%d+%d > %d)",
  31 @@ -981,6 +981,8 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
  32                 }
  33                 wpabuf_put_data(data->inbuf, pos, len);
  34                 data->in_frag_pos += len;
  35 +       }
  36 +       if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
  37                 wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
  38                            (int) len);
  39                 return;
  40 @@ -990,8 +992,6 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv,
  41          * buffering fragments so that's how we know it's the last)
  42          */
  43         if (data->in_frag_pos) {
  44 -               wpabuf_put_data(data->inbuf, pos, len);
  45 -               data->in_frag_pos += len;
  46                 pos = wpabuf_head_u8(data->inbuf);
  47                 len = data->in_frag_pos;
  48                 wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
  49 --
  50 1.9.1
  51