From: Johannes Berg johannes.berg@intel.com
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 shuster@seemoo.tu-darmstadt.de Tested-by: Sönke Huster shuster@seemoo.tu-darmstadt.de Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning") Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/wireless/scan.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -423,6 +423,15 @@ cfg80211_add_nontrans_list(struct cfg802
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;