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 674001A735 for ; Mon, 9 Oct 2023 13:28:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mPcZnemv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9BBEC433CB; Mon, 9 Oct 2023 13:28:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858122; bh=wmEY0wH7Na7AHPGM5Lq31apKdbDq9YrFo1+RBc2IVKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mPcZnemvIU7PaY+Td3prZuEsaiPoI+7Vvbmdhiw1eiieNtfpaX6a8CooIbEp+gjjd pBEVbH2IMzXGEhCYmOGd+jZWAuSZLRwKqeUhLia7D5oZrH5NVxQb7V3MjofwSvvic4 Pws/gncfEq4eb55iBrUNK1ZWC40dcWsbfgfqvc+o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Ahern , Kyle Zeng , Stephen Suryaputra , Vadim Fedorenko , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 023/131] ipv4: fix null-deref in ipv4_link_failure Date: Mon, 9 Oct 2023 15:01:03 +0200 Message-ID: <20231009130117.018605773@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130116.329529591@linuxfoundation.org> References: <20231009130116.329529591@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kyle Zeng [ Upstream commit 0113d9c9d1ccc07f5a3710dac4aa24b6d711278c ] Currently, we assume the skb is associated with a device before calling __ip_options_compile, which is not always the case if it is re-routed by ipvs. When skb->dev is NULL, dev_net(skb->dev) will become null-dereference. This patch adds a check for the edge case and switch to use the net_device from the rtable when skb->dev is NULL. Fixes: ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure") Suggested-by: David Ahern Signed-off-by: Kyle Zeng Cc: Stephen Suryaputra Cc: Vadim Fedorenko Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/route.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 7004e379c325f..f82d456afd0ed 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1221,6 +1221,7 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie) static void ipv4_send_dest_unreach(struct sk_buff *skb) { + struct net_device *dev; struct ip_options opt; int res; @@ -1238,7 +1239,8 @@ static void ipv4_send_dest_unreach(struct sk_buff *skb) opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr); rcu_read_lock(); - res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); + dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev; + res = __ip_options_compile(dev_net(dev), &opt, skb, NULL); rcu_read_unlock(); if (res) -- 2.40.1