Commit 567e14e3 authored by Johannes Berg's avatar Johannes Berg
Browse files

wifi: cfg80211: ensure length byte is present before access 



When iterating the elements here, ensure the length byte is
present before checking it to see if the entire element will
fit into the buffer.

Longer term, we should rewrite this code using the type-safe
element iteration macros that check all of this.

Fixes: 0b8fb823 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Reported-by: default avatarSoenke Huster <shuster@seemoo.tu-darmstadt.de>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent ff05d4b4

net/wireless/scan.c

+4 −2
Original line number Diff line number Diff line
@@ -304,7 +304,8 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen, 
	tmp_old = cfg80211_find_ie(WLAN_EID_SSID, ie, ielen);

	tmp_old = (tmp_old) ? tmp_old + tmp_old[1] + 2 : ie;



	while (tmp_old + tmp_old[1] + 2 - ie <= ielen) {

	while (tmp_old + 2 - ie <= ielen &&

	       tmp_old + tmp_old[1] + 2 - ie <= ielen) {

		if (tmp_old[0] == 0) {

			tmp_old++;

			continue;
@@ -364,7 +365,8 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen, 
	 * copied to new ie, skip ssid, capability, bssid-index ie

	 */

	tmp_new = sub_copy;

	while (tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {

	while (tmp_new + 2 - sub_copy <= subie_len &&

	       tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {

		if (!(tmp_new[0] == WLAN_EID_NON_TX_BSSID_CAP ||

		      tmp_new[0] == WLAN_EID_SSID)) {

			memcpy(pos, tmp_new, tmp_new[1] + 2);