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 91CC93C07A; Mon, 23 Mar 2026 14:11:39 +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=1774275099; cv=none; b=TBTUGew693Nyq7HDUU8w236mXo7JeKV4kZSFLIPQgLJ2tu/FR1oeMQ12iEIUJZ/D+uae8wdqrEehZHgWnvUpiKJv9/mbMRF6F9zldEmZahFuckumNUk7yNJR+dYK+F8LG1MvyBWZ9+aE5fCDsfCf7HZOTnzAAcmOEmej9P1DHM4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774275099; c=relaxed/simple; bh=oceo1N62d3bESwko1tkg8uojxqrpY37DpGU1UrrNKyg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gl3dmKvptpA3FRmDZ0pAWg+4Do0urWqDvOuJv0fdmrt5ZDkWHyfg51KMPC8ZxLsvAzr8WTf2uc0WjrYJcT/wZH+OxHJxrKXaZFgjMQrKSOpKEPrwm5ObWPp2vTXY+Dmw5b4Ne5ChSEOzuDkbOmnvpWziWS992pk7TPFQgnLjOqQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mP8/87mJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mP8/87mJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24D9AC2BC9E; Mon, 23 Mar 2026 14:11:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774275099; bh=oceo1N62d3bESwko1tkg8uojxqrpY37DpGU1UrrNKyg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mP8/87mJGh2AEjzNbgePI6J8jJt1gyaaGaa++T4/XuOu9/32rKDKR2hQo7/lbAXtP y7RJMQ1Kuk/dRJyo+x3HGzQIsPx/0k22HiXB0JRvcUPqhehdV+H3QfOchem1KgnmsX RjFxnd6TM+O+iFrC8kIbKoXO5V08Z8TisQJ32uME= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 169/212] udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n Date: Mon, 23 Mar 2026 14:46:30 +0100 Message-ID: <20260323134509.068548470@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134503.770111826@linuxfoundation.org> References: <20260323134503.770111826@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit b3a6df291fecf5f8a308953b65ca72b7fc9e015d ] When CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0 (success) without actually creating a socket. Callers such as fou_create() then proceed to dereference the uninitialized socket pointer, resulting in a NULL pointer dereference. The captured NULL deref crash: BUG: kernel NULL pointer dereference, address: 0000000000000018 RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764) [...] Call Trace: genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114) genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209) [...] netlink_rcv_skb (net/netlink/af_netlink.c:2550) genl_rcv (net/netlink/genetlink.c:1219) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1)) __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1)) __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1)) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130) This patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so callers correctly take their error paths. There is only one caller of the vulnerable function and only privileged users can trigger it. Fixes: fd384412e199b ("udp_tunnel: Seperate ipv6 functions into its own file.") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Link: https://patch.msgid.link/20260317010241.1893893-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/udp_tunnel.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h index 9acef2fbd2fdc..d97ee26ba4f66 100644 --- a/include/net/udp_tunnel.h +++ b/include/net/udp_tunnel.h @@ -47,7 +47,7 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg, static inline int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg, struct socket **sockp) { - return 0; + return -EPFNOSUPPORT; } #endif -- 2.51.0