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=...
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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;