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

   1 From ef566a4d4f74022e1fdb0a2addfe81e6de9f4aae Mon Sep 17 00:00:00 2001
   2 From: Jouni Malinen <j@w1.fi>
   3 Date: Wed, 29 Apr 2015 02:21:53 +0300
   4 Subject: [PATCH] AP WMM: Fix integer underflow in WMM Action frame parser
   5
   6 The length of the WMM Action frame was not properly validated and the
   7 length of the information elements (int left) could end up being
   8 negative. This would result in reading significantly past the stack
   9 buffer while parsing the IEs in ieee802_11_parse_elems() and while doing
  10 so, resulting in segmentation fault.
  11
  12 This can result in an invalid frame being used for a denial of service
  13 attack (hostapd process killed) against an AP with a driver that uses
  14 hostapd for management frame processing (e.g., all mac80211-based
  15 drivers).
  16
  17 Thanks to Kostya Kortchinsky of Google security team for discovering and
  18 reporting this issue.
  19
  20 Signed-off-by: Jouni Malinen <j@w1.fi>
  21 ---
  22  src/ap/wmm.c | 3 +++
  23  1 file changed, 3 insertions(+)
  24
  25 --- a/src/ap/wmm.c
  26 +++ b/src/ap/wmm.c
  27 @@ -274,6 +274,9 @@ void hostapd_wmm_action(struct hostapd_d
  28                 return;
  29         }
  30
  31 +       if (left < 0)
  32 +               return; /* not a valid WMM Action frame */
  33 +
  34         /* extract the tspec info element */
  35         if (ieee802_11_parse_elems(pos, left, &elems, 1) == ParseFailed) {
  36                 hostapd_logger(hapd, mgmt->sa, HOSTAPD_MODULE_IEEE80211,