From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793198242; b=BVMCON45xJvIjK5jPF/U5Yhq5b9tVVqq7NHBj8jXD554lob/Ai72IJ21kSiuGnoEJj0C OhrHdj58IQuHlyf54iPX0RZqu5EL0Utqu7RXrEXbWk/4P2J2QCC1CkPCr75F2+BhVLsLp /LbU0O0j+ML1QDVGpYd6NBBlO3J3dyaW+ihxGGEDYSxTQhrNFpCUXO1KIcIzPyQdQa3GF 6Yit+uqpNeAlraqyVX+mRc3IA3xhCiWQmB2VmWblk2IT1k02WqwQk8wdz3yawGaW942Zf 0YgE127jxRyEucVHEarBYK6NSQe8TkI5VdKwpJ8XTRKVV8h1PGr7omxozWgLNdEC5dg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793198242; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:Content-Language:To:Cc:References:From:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=pPQxkHJYfqZk37WDAM2FHcljmku7bcSuOn2JFLL4Fyg=; b=1BUVzkzHrKcRpxpIj8qYB2XsVGkv6As7FpnVbnO/8r5P3cjMPyWwxsZ0tq7u8nrqx4Z2 Fk7x0j4AeW26R/JH9WI/12xLOEbG2/thYS8iTRZTQxDTerbKzFIK3hpJYDmq0lZ2tvWaR Ky7s4IcWH9B/V1YVdqU/Kn7XAAq16HXtWw5qQ0t8wO0+/G3oXjIMGI4UEh6Vz02DU1QSy rCbsYBnj40hfgjYwBvawPYNxFRooS0jPuQGxKeMJ+OlaVY1Ia8sUKgUZs0uMx3gdxJ1m5 Lh1XsFulZChwxGotmXztVN/G6tfLYYjpPdgHtI6yrL6SWdMhmy8FKMrLUyyADaorS0g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=lcWp7mA5; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC318606A31A; Wed, 28 Oct 2026 14:37:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=lcWp7mA5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDC401F01825; Wed, 28 Oct 2026 14:37:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793198241; bh=pPQxkHJYfqZk37WDAM2FHcljmku7bcSuOn2JFLL4Fyg=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=lcWp7mA5XJFge5P7O7vqY2e/Ljb3SfS35Bzk61em8A05dZJFv76+x1DDJarDWRYZi eTzpoMZBE6L6GJvGsuwkul42005ckd4ieU8kcgMIzgf6CUc6ZXIJLibLh6P0dhuXI2 QhGGUGM7eSjq/ucZPJfGZmwwT2TfyTQv1GTcQGoTm7Qh2zG7dUaFHCTknW/ISa896R mzLka157H5tLaLS0/YPHKAUsXWGEAh6bRj6XC/jn23eDObvHgIG81zg2g7IwgCEh+v Xfxjh0chl8Fhld0zY6BwgpwSmF3C92JNdGJ5/eeQf1lZUHPt6dPpGXzBKXV19+dYYC 9eI/IeMow8kGg== Message-ID: <15556a7f-c9e4-4ada-9810-9bf64d67164a@kernel.org> Date: Wed, 28 Oct 2026 08:37:20 -0600 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net v2] ipv6: raw: fix use-after-free in rawv6_send_hdrinc() Content-Language: en-US To: Hangbin Liu , Antoine Tenart Cc: Zhou Qiuyue , netdev@vger.kernel.org, Ido Schimmel , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20261026044808.613-1-n0ps1edzz@gmail.com> From: David Ahern In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/27/26 7:27 PM, Hangbin Liu wrote: > On Tue, Oct 27, 2026 at 10:43:48AM +0100, Antoine Tenart wrote: >> On Tue, Oct 27, 2026 at 09:38:34AM +0800, Hangbin Liu wrote: >>> On Mon, Oct 26, 2026 at 04:07:40PM +0100, Antoine Tenart wrote: >>>> On Mon, Oct 26, 2026 at 02:09:23PM +0800, Hangbin Liu wrote: >>>>> On Mon, Oct 26, 2026 at 12:48:08PM +0800, Zhou Qiuyue wrote: >>>>>> diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c >>>>>> index b965258cf..bdea82543 100644 >>>>>> --- a/net/ipv6/raw.c >>>>>> +++ b/net/ipv6/raw.c >>>>>> @@ -654,6 +654,9 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length, >>>>>> if (unlikely(!skb)) >>>>>> return 0; >>>>>> >>>>>> + /* l3mdev_ip6_out() may have replaced the skb dst. */ >>>>>> + rt = dst_rt6_info(skb_dst(skb)); >>>>>> + >>>>>> /* Acquire rcu_read_lock() in case we need to use rt->rt6i_idev >>>>>> * in the error path. Since skb has been freed, the dst could >>>>>> * have been queued for deletion. >>>>> >>>>> Reviewed-by: Hangbin Liu >>>> >>>> Doesn't this change the device seen by the nf hook / used for the stats? >>> >>> Should we still use the old/released rt->dst.dev after the VRF output >>> path replace skb->dst? vrf_ip6_out_redirect() said it allows the nf hook >>> use vrf device. >> >> Right, but then in the direct path the NF_INET_LOCAL_OUT hook would be >> run twice with the same dev. Looking at other call sites for >> l3mdev_ip6_out, it's not clear either, __ip6_local_out reloads the dev >> while ip6_xmit does not. I'm not sure what is the expected behavior. > > Hmm, me neither. David might know. > I do not recall the original behavior; that was many years ago.