From 9f16b5c82a025cd4c864737409234ddc44fb166a Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 25 Nov 2022 12:36:57 +0100 Subject: [PATCH] wifi: cfg80211: fix buffer overflow in elem comparison MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit For vendor elements, the code here assumes that 5 octets are present without checking. Since the element itself is already checked to fit, we only need to check the length. Reported-and-tested-by: Sönke Huster Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning") Signed-off-by: Johannes Berg --- net/wireless/scan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index da752b0..4d21779 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -330,7 +330,8 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen, * determine if they are the same ie. */ if (tmp_old[0] == WLAN_EID_VENDOR_SPECIFIC) { - if (!memcmp(tmp_old + 2, tmp + 2, 5)) { + if (tmp_old[1] >= 5 && tmp[1] >= 5 && + !memcmp(tmp_old + 2, tmp + 2, 5)) { /* same vendor ie, copy from * subelement */ -- 2.7.4