package/wpa_supplicant/0003-EAP-pwd-peer-Fix-last-fragment-length-validation.patch

   1 From 8057821706784608b828e769ccefbced95591e50 Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Sun, 1 Nov 2015 18:18:17 +0200
   4 Subject: [PATCH] EAP-pwd peer: 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-2015-5315)
  12
  13 Signed-off-by: Jouni Malinen <j@w1.fi>
  14 ---
  15  src/eap_peer/eap_pwd.c | 7 +++----
  16  1 file changed, 3 insertions(+), 4 deletions(-)
  17
  18 diff --git a/src/eap_peer/eap_pwd.c b/src/eap_peer/eap_pwd.c
  19 index 1f78544..75ceef1 100644
  20 --- a/src/eap_peer/eap_pwd.c
  21 +++ b/src/eap_peer/eap_pwd.c
  22 @@ -903,7 +903,7 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
  23         /*
  24          * buffer and ACK the fragment
  25          */
  26 -       if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
  27 +       if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
  28                 data->in_frag_pos += len;
  29                 if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
  30                         wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
  31 @@ -916,7 +916,8 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
  32                         return NULL;
  33                 }
  34                 wpabuf_put_data(data->inbuf, pos, len);
  35 -
  36 +       }
  37 +       if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
  38                 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
  39                                      EAP_PWD_HDR_SIZE,
  40                                      EAP_CODE_RESPONSE, eap_get_id(reqData));
  41 @@ -930,10 +931,8 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
  42          * we're buffering and this is the last fragment
  43          */
  44         if (data->in_frag_pos) {
  45 -               wpabuf_put_data(data->inbuf, pos, len);
  46                 wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
  47                            (int) len);
  48 -               data->in_frag_pos += len;
  49                 pos = wpabuf_head_u8(data->inbuf);
  50                 len = data->in_frag_pos;
  51         }
  52 --
  53 1.9.1
  54