From 39f7362328cbd18c4494e470d01928c86f4b2dee 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 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: b397b5577905 ("cfg80211: Parsing of Multiple BSSID information in scanning") Reported-by: Soenke Huster Signed-off-by: Johannes Berg --- 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 5dab33e1f3a81..a183f2b758742 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -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); -- 2.39.5