From: Johannes Berg Date: Fri, 30 Sep 2022 22:01:44 +0000 (+0200) Subject: wifi: cfg80211: avoid nontransmitted BSS list corruption X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0a8ee682e4f992eccce226b012bba600bb2251e2;p=linux.git wifi: cfg80211: avoid nontransmitted BSS list corruption commit bcca852027e5878aec911a347407ecc88d6fff7f upstream. If a non-transmitted BSS shares enough information (both SSID and BSSID!) with another non-transmitted BSS of a different AP, then we can find and update it, and then try to add it to the non-transmitted BSS list. We do a search for it on the transmitted BSS, but if it's not there (but belongs to another transmitted BSS), the list gets corrupted. Since this is an erroneous situation, simply fail the list insertion in this case and free the non-transmitted BSS. This fixes CVE-2022-42721. Reported-by: Sönke Huster Tested-by: Sönke Huster Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning") Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 2e576714e9891..a21baf7b36122 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -425,6 +425,15 @@ cfg80211_add_nontrans_list(struct cfg80211_bss *trans_bss, rcu_read_unlock(); + /* + * This is a bit weird - it's not on the list, but already on another + * one! The only way that could happen is if there's some BSSID/SSID + * shared by multiple APs in their multi-BSSID profiles, potentially + * with hidden SSID mixed in ... ignore it. + */ + if (!list_empty(&nontrans_bss->nontrans_list)) + return -EINVAL; + /* add to the list */ list_add_tail(&nontrans_bss->nontrans_list, &trans_bss->nontrans_list); return 0;