From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2036131B822 for ; Wed, 26 Nov 2025 10:26:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764152791; cv=none; b=oV56YVsHWqP6Dr2Ky+dRptWKRTYYvn89r6Kl+4j0Dd2pcRVKa+RMkSNAT0WKgzJTe3D3Uw/bK3HlMS/iqQ8d52Fwt5LPJ3mUQO0/2B1PKgUN1BZrheFyShG+Cr79hjBj74ztQgZkNvvEc0uvVX7YdsLjrY7FedyGlsXzo8gT0UM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764152791; c=relaxed/simple; bh=ogXONSA9Fs4JaC6IWq0Wj8CqDg5KXtavSmanR7JQSok=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=um+pb7YnhsV3i8zRmdVK7dgIUYW1atLnZ5j9BZmbUpYf/gv9peOK1tGAPFMuVeWWU5lWFu6C+++bnxyVd6mLngzG/4YM8bdMM6KpadKg3Amfqe2L+oleW4foJrOf5gBRpUlo2aNqMOkJFl27BkbPHfZdNaCjcvHSLbLToZgMYZk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YEnbxhpD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YEnbxhpD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 263F4C2BC87; Wed, 26 Nov 2025 10:26:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764152790; bh=ogXONSA9Fs4JaC6IWq0Wj8CqDg5KXtavSmanR7JQSok=; h=From:To:Cc:Subject:Date:From; b=YEnbxhpDFpa/1KXLU+I3BOaZz02oZktGP3hhtpGzKHpKwIeGa0nT6BRcbigRf6Zqn 94UFQeR5V4gEeFcebwcU4SNQiqQq1YKHhWefuYRJH6qrhfBO/sQnnWqulc9FIMBxvq SVhUHswKAeU+1AOt90XFnFwBJ9/PsGyzIw++kNbLU4moc5CY9Sjr/TdWiTHYJYfX/Y emvRM6HBc5eGZDlWmRqqPu0Hvtj8V2EK7aXFDYysErQoBWpBzIQ83FTvfEQtsnBOKS MoCjeOl51PtlksdUXRZ0zemYkcTRpZXeF0zE9BlgJRn1HFQN1zQx9QvmQWipBwhcDz qC+kbADcgR1KQ== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, andrew+netdev@lunn.ch Cc: Antoine Tenart , netdev@vger.kernel.org, Liang Li , Beniamino Galvani Subject: [PATCH net v2] net: vxlan: prevent NULL deref in vxlan_xmit_one Date: Wed, 26 Nov 2025 11:26:25 +0100 Message-ID: <20251126102627.74223-1-atenart@kernel.org> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Neither sock4 nor sock6 pointers are guaranteed to be non-NULL in vxlan_xmit_one, e.g. if the iface is brought down. This can lead to the following NULL dereference: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:vxlan_xmit_one+0xbb3/0x1580 Call Trace: vxlan_xmit+0x429/0x610 dev_hard_start_xmit+0x55/0xa0 __dev_queue_xmit+0x6d0/0x7f0 ip_finish_output2+0x24b/0x590 ip_output+0x63/0x110 Mentioned commits changed the code path in vxlan_xmit_one and as a side effect the sock4/6 pointer validity checks in vxlan(6)_get_route were lost. Fix this by adding back checks. Since both commits being fixed were released in the same version (v6.7) and are strongly related, bundle the fixes in a single commit. Reported-by: Liang Li Fixes: 6f19b2c136d9 ("vxlan: use generic function for tunnel IPv4 route lookup") Fixes: 2aceb896ee18 ("vxlan: use generic function for tunnel IPv6 route lookup") Cc: Beniamino Galvani Signed-off-by: Antoine Tenart --- Since v1: - Fixed uninitialized err variable reported by clang [Jakub] drivers/net/vxlan/vxlan_core.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index a5c55e7e4d79..e957aa12a8a4 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2349,7 +2349,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, int addr_family; __u8 tos, ttl; int ifindex; - int err; + int err = 0; u32 flags = vxlan->cfg.flags; bool use_cache; bool udp_sum = false; @@ -2454,12 +2454,18 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, rcu_read_lock(); if (addr_family == AF_INET) { - struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock); + struct vxlan_sock *sock4; u16 ipcb_flags = 0; struct rtable *rt; __be16 df = 0; __be32 saddr; + sock4 = rcu_dereference(vxlan->vn4_sock); + if (unlikely(!sock4)) { + reason = SKB_DROP_REASON_DEV_READY; + goto tx_error; + } + if (!ifindex) ifindex = sock4->sock->sk->sk_bound_dev_if; @@ -2534,10 +2540,16 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, ipcb_flags); #if IS_ENABLED(CONFIG_IPV6) } else { - struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock); + struct vxlan_sock *sock6; struct in6_addr saddr; u16 ip6cb_flags = 0; + sock6 = rcu_dereference(vxlan->vn6_sock); + if (unlikely(!sock6)) { + reason = SKB_DROP_REASON_DEV_READY; + goto tx_error; + } + if (!ifindex) ifindex = sock6->sock->sk->sk_bound_dev_if; -- 2.52.0