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

   1 From: Johannes Berg <johannes.berg@intel.com>
   2 Date: Thu, 29 Sep 2022 21:50:44 +0200
   3 Subject: [PATCH] wifi: cfg80211: ensure length byte is present before
   4  access
   5
   6 commit 567e14e39e8f8c6997a1378bc3be615afca86063 upstream.
   7
   8 When iterating the elements here, ensure the length byte is
   9 present before checking it to see if the entire element will
  10 fit into the buffer.
  11
  12 Longer term, we should rewrite this code using the type-safe
  13 element iteration macros that check all of this.
  14
  15 Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
  16 Reported-by: Soenke Huster <shuster@seemoo.tu-darmstadt.de>
  17 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
  18 ---
  19
  20 --- a/net/wireless/scan.c
  21 +++ b/net/wireless/scan.c
  22 @@ -304,7 +304,8 @@ static size_t cfg80211_gen_new_ie(const
  23         tmp_old = cfg80211_find_ie(WLAN_EID_SSID, ie, ielen);
  24         tmp_old = (tmp_old) ? tmp_old + tmp_old[1] + 2 : ie;
  25
  26 -       while (tmp_old + tmp_old[1] + 2 - ie <= ielen) {
  27 +       while (tmp_old + 2 - ie <= ielen &&
  28 +              tmp_old + tmp_old[1] + 2 - ie <= ielen) {
  29                 if (tmp_old[0] == 0) {
  30                         tmp_old++;
  31                         continue;
  32 @@ -364,7 +365,8 @@ static size_t cfg80211_gen_new_ie(const
  33          * copied to new ie, skip ssid, capability, bssid-index ie
  34          */
  35         tmp_new = sub_copy;
  36 -       while (tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {
  37 +       while (tmp_new + 2 - sub_copy <= subie_len &&
  38 +              tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {
  39                 if (!(tmp_new[0] == WLAN_EID_NON_TX_BSSID_CAP ||
  40                       tmp_new[0] == WLAN_EID_SSID)) {
  41                         memcpy(pos, tmp_new, tmp_new[1] + 2);