[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20221013175144.181064984@linuxfoundation.org>
Date: Thu, 13 Oct 2022 19:52:46 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Kees Cook <keescook@...omium.org>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH 5.15 17/27] wifi: cfg80211/mac80211: reject bad MBSSID elements
From: Johannes Berg <johannes.berg@...el.com>
commit 8f033d2becc24aa6bfd2a5c104407963560caabc upstream.
Per spec, the maximum value for the MaxBSSID ('n') indicator is 8,
and the minimum is 1 since a multiple BSSID set with just one BSSID
doesn't make sense (the # of BSSIDs is limited by 2^n).
Limit this in the parsing in both cfg80211 and mac80211, rejecting
any elements with an invalid value.
This fixes potentially bad shifts in the processing of these inside
the cfg80211_gen_new_bssid() function later.
I found this during the investigation of CVE-2022-41674 fixed by the
previous patch.
Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Fixes: 78ac51f81532 ("mac80211: support multi-bssid")
Reviewed-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/mac80211/util.c | 2 ++
net/wireless/scan.c | 2 ++
2 files changed, 4 insertions(+)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1414,6 +1414,8 @@ static size_t ieee802_11_find_bssid_prof
for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, start, len) {
if (elem->datalen < 2)
continue;
+ if (elem->data[0] < 1 || elem->data[0] > 8)
+ continue;
for_each_element(sub, elem->data + 1, elem->datalen - 1) {
u8 new_bssid[ETH_ALEN];
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -2103,6 +2103,8 @@ static void cfg80211_parse_mbssid_data(s
for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, ie, ielen) {
if (elem->datalen < 4)
continue;
+ if (elem->data[0] < 1 || (int)elem->data[0] > 8)
+ continue;
for_each_element(sub, elem->data + 1, elem->datalen - 1) {
u8 profile_len;
Powered by blists - more mailing lists