From 010f245b9dd734adda6386c494a4ace953ea8dc4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 17 Oct 2017 10:07:44 -0700 Subject: [PATCH] tun: relax check on eth_get_headlen() return value syzkaller hit the WARN() in tun_get_user(), providing skb with payload in fragments only, and nothing in skb->head GRO layer is fine with this, so relax the check. Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 57e4c31fa84a..c64ec19af9b7 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1737,7 +1737,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, /* Exercise flow dissector code path. */ u32 headlen = eth_get_headlen(skb->data, skb_headlen(skb)); - if (headlen > skb_headlen(skb) || headlen < ETH_HLEN) { + if (unlikely(headlen > skb_headlen(skb))) { this_cpu_inc(tun->pcpu_stats->rx_dropped); napi_free_frags(&tfile->napi); mutex_unlock(&tfile->napi_mutex);