From 359ce507f751d5d7027be5f64a88127621816803 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 29 Sep 2022 21:50:44 +0200 Subject: [PATCH] wifi: cfg80211: ensure length byte is present before access 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 Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/scan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index e0dd0249d026..32d6532ce922 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -265,7 +265,8 @@ 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; @@ -325,7 +326,8 @@ 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);