From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EE0D42C0F93; Thu, 30 Jul 2026 15:01:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423705; cv=none; b=Q4uJksiMkbaL/4lo6ewx0vsTAkughVvrvmtEApPSjufLPosDXQS5z42NsA4rn740HkMctxh0BJKTPN1GpX7WJId3H7eJw3+sRK0SSonbsPSzmAS+R1ziRQKPLa/FnxD8z6ZP9HtB5JFmPvuzGcm9YMqubrBCldbJX9PcyFX7pXA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423705; c=relaxed/simple; bh=Kejhq/vnUx2SfTs9UyhdQXHRueJtOeQGCpHGJB+RMHY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EBT5G4UrjiBrPa6sB/RGcprIGp9xjyi4wtVLwJ0GDjnKYlZ8FT7c8Qp1UMt/zN6ddfMk+gSMP+eIu7lfeCvEYMW5YvfIpiupv3wepgpzjcqGiegDSSofXvP3bebcUVjEOdRrzKpZiUT7KFHL7ATkvmxEX6varN32W8LfnXlg1F0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DQIZb15t; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DQIZb15t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B5AE1F000E9; Thu, 30 Jul 2026 15:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785423703; bh=x/8ZyCqB0cV7lMU86fFcNvsYiACmje1lX4iBmGrskUM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DQIZb15ty+ktcqnsAeyGHkG+OuaVZfTWf5jX800M3Xl11CKlHz5qBYe3wjLiWflW+ 3sArz5USduy65VriZDNZVZXVPEWPHV3zGpoAZ3pGdK6U6VMyZlPvXVNdRlMshDsI/+ R3+8H7JnNpk82pQu41RP5Bgb9rMtll3/uLGFN/sA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Weiming Shi , David Ahern , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 138/675] mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n Date: Thu, 30 Jul 2026 16:07:48 +0200 Message-ID: <20260730141448.071292661@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit 56d96fededd61192cd7cc8d2b0f36adfd59036c3 ] On CONFIG_INET=n builds, mpls_valid_fib_dump_req() walks the parsed attribute table itself instead of calling ip_valid_fib_dump_req(). The RTA_OIF arm passes tb[RTA_OIF] to nla_get_u32() without checking it is present, so an RTM_GETROUTE dump for AF_MPLS with strict checking and no RTA_OIF hits a NULL dereference. RTM_GETROUTE is RTNL_KIND_GET, which rtnetlink_rcv_msg() permits without CAP_NET_ADMIN, so an unprivileged user can trigger it. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:mpls_valid_fib_dump_req (net/mpls/af_mpls.c:2189) Call Trace: mpls_dump_routes (net/mpls/af_mpls.c:2236) netlink_dump (net/netlink/af_netlink.c:2331) __netlink_dump_start (net/netlink/af_netlink.c:2446) rtnetlink_rcv_msg (net/core/rtnetlink.c:7033) netlink_rcv_skb (net/netlink/af_netlink.c:2556) netlink_unicast (net/netlink/af_netlink.c:1345) netlink_sendmsg (net/netlink/af_netlink.c:1900) __sock_sendmsg (net/socket.c:790) ____sys_sendmsg (net/socket.c:2684) ___sys_sendmsg (net/socket.c:2738) __sys_sendmsg (net/socket.c:2770) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Skip unset attributes, as ip_valid_fib_dump_req() does. Fixes: 196cfebf8972 ("net/mpls: Handle kernel side filtering of route dumps") Assisted-by: Claude:claude-opus-4-8 Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: David Ahern Link: https://patch.msgid.link/20260711114958.1009619-3-bestswngs@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/mpls/af_mpls.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 1c70cb26e7ba17..f7f60025d042a4 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -2123,6 +2123,9 @@ static int mpls_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh, int ifindex; if (i == RTA_OIF) { + if (!tb[i]) + continue; + ifindex = nla_get_u32(tb[i]); filter->dev = __dev_get_by_index(net, ifindex); if (!filter->dev) -- 2.53.0