From: Johannes Berg <johannes.berg@intel.com> stable inclusion from stable-v5.10.148 commit e7aa7fd10eba32835de3dfa7f1691a90043faa73 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0WL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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@chromium.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> --- net/mac80211/util.c | 2 ++ net/wireless/scan.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/net/mac80211/util.c b/net/mac80211/util.c index c2eae5270ee5..764a6655f513 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1409,6 +1409,8 @@ static size_t ieee802_11_find_bssid_profile(const u8 *start, size_t len, 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]; diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 1c883c2856f5..b5e6870faaeb 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -2103,6 +2103,8 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy, 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; -- 2.25.1