From: Bryam Vargas Date: Sun, 21 Jun 2026 02:45:18 +0000 (-0500) Subject: wifi: mac80211_hwsim: clamp virtio RX length before skb_put X-Git-Tag: v7.2-rc4~17^2~16^2~38 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=10a2b430f8f06ae14b9590b6f6faa6b588ef0654;p=thirdparty%2Fkernel%2Flinux.git wifi: mac80211_hwsim: clamp virtio RX length before skb_put hwsim_virtio_rx_work() passes the virtqueue used-ring length reported by the device straight to skb_put() on a fixed-size receive skb. A backend reporting a length larger than the skb tailroom drives skb_put() past the buffer end and hits skb_over_panic() -- a host-triggerable guest panic (denial of service). Clamp the length to the skb's available room before skb_put(). A conforming device never reports more than the posted buffer size, so valid frames are unaffected; a truncated over-report then fails the length/header checks in hwsim_virtio_handle_cmd() and is dropped, so truncating rather than dropping here cannot be turned into a parsing problem. Fixes: 5d44fe7c9808 ("mac80211_hwsim: add frame transmission support over virtio") Signed-off-by: Bryam Vargas Link: https://patch.msgid.link/20260620-b4-disp-474bee37-v1-1-1a4d37f3e2d4@proton.me Signed-off-by: Johannes Berg --- diff --git a/drivers/net/wireless/virtual/mac80211_hwsim_main.c b/drivers/net/wireless/virtual/mac80211_hwsim_main.c index 0dd8a6c85953..5c1718277599 100644 --- a/drivers/net/wireless/virtual/mac80211_hwsim_main.c +++ b/drivers/net/wireless/virtual/mac80211_hwsim_main.c @@ -7289,6 +7289,7 @@ static void hwsim_virtio_rx_work(struct work_struct *work) skb->data = skb->head; skb_reset_tail_pointer(skb); + len = min(len, skb_end_offset(skb)); skb_put(skb, len); hwsim_virtio_handle_cmd(skb);