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wifi: cfg80211: ensure length byte is present before access

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commit 567e14e39e8f8c6997a1378bc3be615afca86063 upstream.

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: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Reported-by: Soenke Huster <shuster@seemoo.tu-darmstadt.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Berg 2022-09-29 21:50:44 +02:00 committed by Greg Kroah-Hartman
parent e7aa7fd10e
commit 6144c97f96
1 changed files with 4 additions and 2 deletions
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6
net/wireless/scan.c
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@ -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);