From: Kees Cook Date: Fri, 9 May 2025 18:46:45 +0000 (-0700) Subject: wifi: mac80211: Set n_channels after allocating struct cfg80211_scan_request X-Git-Tag: v6.15-rc7~26^2~3^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=82bbe02b2500ef0a62053fe2eb84773fe31c5a0a;p=thirdparty%2Flinux.git wifi: mac80211: Set n_channels after allocating struct cfg80211_scan_request Make sure that n_channels is set after allocating the struct cfg80211_registered_device::int_scan_req member. Seen with syzkaller: UBSAN: array-index-out-of-bounds in net/mac80211/scan.c:1208:5 index 0 is out of range for type 'struct ieee80211_channel *[] __counted_by(n_channels)' (aka 'struct ieee80211_channel *[]') This was missed in the initial conversions because I failed to locate the allocation likely due to the "sizeof(void *)" not matching the "channels" array type. Reported-by: syzbot+4bcdddd48bb6f0be0da1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/680fd171.050a0220.2b69d1.045e.GAE@google.com/ Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by") Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Link: https://patch.msgid.link/20250509184641.work.542-kees@kernel.org Signed-off-by: Johannes Berg --- diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 741e6c7edcb7c..6b6de43d9420a 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -1354,10 +1354,12 @@ int ieee80211_register_hw(struct ieee80211_hw *hw) hw->wiphy->software_iftypes |= BIT(NL80211_IFTYPE_MONITOR); - local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) + - sizeof(void *) * channels, GFP_KERNEL); + local->int_scan_req = kzalloc(struct_size(local->int_scan_req, + channels, channels), + GFP_KERNEL); if (!local->int_scan_req) return -ENOMEM; + local->int_scan_req->n_channels = channels; eth_broadcast_addr(local->int_scan_req->bssid);