Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:wifi: cfg80211: regulatory: improve invalid hints checkingSyzbot keeps reporting an issue [1] that occurs when erroneous symbolssent from userspace get through into user_alpha2[] viaregulatory_hint_user() call. Such invalid regulatory hints should berejected.While a sanity check from commit 47caf685a685 ("cfg80211: regulatory:reject invalid hints") looks to be enough to deter these very cases,there is a way to get around it due to 2 reasons.1) The way isalpha() works, symbols other than latin lower andupper letters may be used to determine a country/domain.For instance, greek letters will also be considered upper/lowerletters and for such characters isalpha() will return true as well.However, ISO-3166-1 alpha2 codes should only hold latincharacters.2) While processing a user regulatory request, betweenreg_process_hint_user() and regulatory_hint_user() there happens tobe a call to queue_regulatory_request() which modifies letters inrequest->alpha2[] with toupper(). This works fine for latin symbols,less so for weird letter characters from the second part of _ctype[].Syzbot triggers a warning in is_user_regdom_saved() by first sendingover an unexpected non-latin letter that gets malformed by toupper()into a character that ends up failing isalpha() check.Prevent this by enhancing is_an_alpha2() to ensure that incomingsymbols are latin letters and nothing else.[1] Syzbot report:------------[ cut here ]------------Unexpected user alpha2: A�WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 is_user_regdom_saved net/wireless/reg.c:440 [inline]WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_alpha2 net/wireless/reg.c:3424 [inline]WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516Modules linked in:CPU: 1 UID: 0 PID: 964 Comm: kworker/1:2 Not tainted 6.12.0-rc5-syzkaller-00044-gc1e939a21eb1 #0Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024Workqueue: events_power_efficient crda_timeout_workRIP: 0010:is_user_regdom_saved net/wireless/reg.c:440 [inline]RIP: 0010:restore_alpha2 net/wireless/reg.c:3424 [inline]RIP: 0010:restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516...Call Trace:
No PoCs from references.
- https://github.com/w4zu/Debian_security