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

   1 From 8c07fa9eda13e835f3f968b2e1c9a8be3a851ff9 Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Thu, 29 Aug 2019 11:52:04 +0300
   4 Subject: [PATCH] AP: Silently ignore management frame from unexpected source
   5  address
   6
   7 Do not process any received Management frames with unexpected/invalid SA
   8 so that we do not add any state for unexpected STA addresses or end up
   9 sending out frames to unexpected destination. This prevents unexpected
  10 sequences where an unprotected frame might end up causing the AP to send
  11 out a response to another device and that other device processing the
  12 unexpected response.
  13
  14 In particular, this prevents some potential denial of service cases
  15 where the unexpected response frame from the AP might result in a
  16 connected station dropping its association.
  17
  18 Signed-off-by: Jouni Malinen <j@w1.fi>
  19 ---
  20  src/ap/drv_callbacks.c | 13 +++++++++++++
  21  src/ap/ieee802_11.c    | 12 ++++++++++++
  22  2 files changed, 25 insertions(+)
  23
  24 --- a/src/ap/drv_callbacks.c
  25 +++ b/src/ap/drv_callbacks.c
  26 @@ -129,6 +129,19 @@ int hostapd_notif_assoc(struct hostapd_d
  27                            "hostapd_notif_assoc: Skip event with no address");
  28                 return -1;
  29         }
  30 +
  31 +       if (is_multicast_ether_addr(addr) ||
  32 +           is_zero_ether_addr(addr) ||
  33 +           os_memcmp(addr, hapd->own_addr, ETH_ALEN) == 0) {
  34 +               /* Do not process any frames with unexpected/invalid SA so that
  35 +                * we do not add any state for unexpected STA addresses or end
  36 +                * up sending out frames to unexpected destination. */
  37 +               wpa_printf(MSG_DEBUG, "%s: Invalid SA=" MACSTR
  38 +                          " in received indication - ignore this indication silently",
  39 +                          __func__, MAC2STR(addr));
  40 +               return 0;
  41 +       }
  42 +
  43         random_add_randomness(addr, ETH_ALEN);
  44
  45         hostapd_logger(hapd, addr, HOSTAPD_MODULE_IEEE80211,
  46 --- a/src/ap/ieee802_11.c
  47 +++ b/src/ap/ieee802_11.c
  48 @@ -3978,6 +3978,18 @@ int ieee802_11_mgmt(struct hostapd_data
  49         fc = le_to_host16(mgmt->frame_control);
  50         stype = WLAN_FC_GET_STYPE(fc);
  51
  52 +       if (is_multicast_ether_addr(mgmt->sa) ||
  53 +           is_zero_ether_addr(mgmt->sa) ||
  54 +           os_memcmp(mgmt->sa, hapd->own_addr, ETH_ALEN) == 0) {
  55 +               /* Do not process any frames with unexpected/invalid SA so that
  56 +                * we do not add any state for unexpected STA addresses or end
  57 +                * up sending out frames to unexpected destination. */
  58 +               wpa_printf(MSG_DEBUG, "MGMT: Invalid SA=" MACSTR
  59 +                          " in received frame - ignore this frame silently",
  60 +                          MAC2STR(mgmt->sa));
  61 +               return 0;
  62 +       }
  63 +
  64         if (stype == WLAN_FC_STYPE_BEACON) {
  65                 handle_beacon(hapd, mgmt, len, fi);
  66                 return 1;