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@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://lore.kernel.org/lkml/680fd171.050a0220.2b69d1.045e.GAE@xxxxxxxxxx/ Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by") Signed-off-by: Kees Cook <kees@xxxxxxxxxx> --- Cc: Edward Adam Davis <eadavis@xxxxxx> Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> Cc: <linux-wireless@xxxxxxxxxxxxxxx> --- net/mac80211/main.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 741e6c7edcb7..6b6de43d9420 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); -- 2.34.1
