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 7C1FB2F0C62; Wed, 20 May 2026 17:44:53 +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=1779299094; cv=none; b=MRhC83fKYalBaUA9qCUaIyigLCTYW7e6zIKYfDrc4QottgKwzBMgqJrlIcBXlF5hcOX1MFyE7RRFmuIMiwFG/utBqy9qZ6MGj62A519b/4Ahtqd2AWkoZ35vl54SJlUhNSI6gfUoJ1GMhK8EeZB35IXbW2wrwn2rCjvvFiP6wpA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779299094; c=relaxed/simple; bh=nTu56Bo7sE4fdvNjOCTktiDs+KaCuRmRF8toGUYv4HY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=inendExvyJdMPz46o5lACEs2M1aT5HNwk2KymRusK/3hu7sLwlUNL4S0aILcm1uAeRbq89yYJZVzPmCDd4Bx3ZEBVQOK/U7gDd2Zf+fESQyWIFZr7cFeW2XtL3DFpNbXmiFdfNnulMY8lFApMzJRvoS1Z1LENMh6qVICQZJG4yE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YKyE2P85; 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="YKyE2P85" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC45A1F000E9; Wed, 20 May 2026 17:44:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779299093; bh=GIln1AT3Mf/lWjHM18AJG252IImhEoacyUpWH6gv/C8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YKyE2P85Q1GrqdIotSFXaPFHWL6gjZD2yrgvp5sJ2nwGq6k7NRQkBvHpECrRrqQLh CufHYldaXAcoueWtRc3nyg3xgLVLJaunwyIfGUSMlaQoz3O6dJswGXvNkFtXGoNMkC RW8ke6sbWm2a7G4+q6diGXIcqCY8wflwMPjrfxzc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Weiming Shi , Ilya Maximets , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 658/957] openvswitch: cap upcall PID array size and pre-size vport replies Date: Wed, 20 May 2026 18:19:01 +0200 Message-ID: <20260520162148.801948597@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162134.554764788@linuxfoundation.org> References: <20260520162134.554764788@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 2091c6aa0df6aba47deb5c8ab232b1cb60af3519 ] The vport netlink reply helpers allocate a fixed-size skb with nlmsg_new(NLMSG_DEFAULT_SIZE, ...) but serialize the full upcall PID array via ovs_vport_get_upcall_portids(). Since ovs_vport_set_upcall_portids() accepts any non-zero multiple of sizeof(u32) with no upper bound, a CAP_NET_ADMIN user can install a PID array large enough to overflow the reply buffer, causing nla_put() to fail with -EMSGSIZE and hitting BUG_ON(err < 0). On systems with unprivileged user namespaces enabled (e.g., Ubuntu default), this is reachable via unshare -Urn since OVS vport mutation operations use GENL_UNS_ADMIN_PERM. kernel BUG at net/openvswitch/datapath.c:2414! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 1 UID: 0 PID: 65 Comm: poc Not tainted 7.0.0-rc7-00195-geb216e422044 #1 RIP: 0010:ovs_vport_cmd_set+0x34c/0x400 Call Trace: genl_family_rcv_msg_doit (net/netlink/genetlink.c:1116) genl_rcv_msg (net/netlink/genetlink.c:1194) netlink_rcv_skb (net/netlink/af_netlink.c:2550) genl_rcv (net/netlink/genetlink.c:1219) netlink_unicast (net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Kernel panic - not syncing: Fatal exception Reject attempts to set more PIDs than nr_cpu_ids in ovs_vport_set_upcall_portids(), and pre-compute the worst-case reply size in ovs_vport_cmd_msg_size() based on that bound, similar to the existing ovs_dp_cmd_msg_size(). nr_cpu_ids matches the cap already used by the per-CPU dispatch configuration on the datapath side (ovs_dp_cmd_fill_info() serialises at most nr_cpu_ids PIDs), so the two sides stay consistent. Fixes: 5cd667b0a456 ("openvswitch: Allow each vport to have an array of 'port_id's.") Reported-by: Xiang Mei Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Weiming Shi Reviewed-by: Ilya Maximets Link: https://patch.msgid.link/20260416024653.153456-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/openvswitch/datapath.c | 35 +++++++++++++++++++++++++++++++++-- net/openvswitch/vport.c | 3 +++ 2 files changed, 36 insertions(+), 2 deletions(-) diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index d5b6e2002bc1f..2304c8e3be4f7 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -2186,9 +2186,40 @@ static int ovs_vport_cmd_fill_info(struct vport *vport, struct sk_buff *skb, return err; } +static size_t ovs_vport_cmd_msg_size(void) +{ + size_t msgsize = NLMSG_ALIGN(sizeof(struct ovs_header)); + + msgsize += nla_total_size(sizeof(u32)); /* OVS_VPORT_ATTR_PORT_NO */ + msgsize += nla_total_size(sizeof(u32)); /* OVS_VPORT_ATTR_TYPE */ + msgsize += nla_total_size(IFNAMSIZ); /* OVS_VPORT_ATTR_NAME */ + msgsize += nla_total_size(sizeof(u32)); /* OVS_VPORT_ATTR_IFINDEX */ + msgsize += nla_total_size(sizeof(s32)); /* OVS_VPORT_ATTR_NETNSID */ + + /* OVS_VPORT_ATTR_STATS */ + msgsize += nla_total_size_64bit(sizeof(struct ovs_vport_stats)); + + /* OVS_VPORT_ATTR_UPCALL_STATS(OVS_VPORT_UPCALL_ATTR_SUCCESS + + * OVS_VPORT_UPCALL_ATTR_FAIL) + */ + msgsize += nla_total_size(nla_total_size_64bit(sizeof(u64)) + + nla_total_size_64bit(sizeof(u64))); + + /* OVS_VPORT_ATTR_UPCALL_PID */ + msgsize += nla_total_size(nr_cpu_ids * sizeof(u32)); + + /* OVS_VPORT_ATTR_OPTIONS(OVS_TUNNEL_ATTR_DST_PORT + + * OVS_TUNNEL_ATTR_EXTENSION(OVS_VXLAN_EXT_GBP)) + */ + msgsize += nla_total_size(nla_total_size(sizeof(u16)) + + nla_total_size(nla_total_size(0))); + + return msgsize; +} + static struct sk_buff *ovs_vport_cmd_alloc_info(void) { - return nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + return genlmsg_new(ovs_vport_cmd_msg_size(), GFP_KERNEL); } /* Called with ovs_mutex, only via ovs_dp_notify_wq(). */ @@ -2198,7 +2229,7 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net, struct sk_buff *skb; int retval; - skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + skb = ovs_vport_cmd_alloc_info(); if (!skb) return ERR_PTR(-ENOMEM); diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c index f0ce8ce1dce0e..1f0c86a9f43b0 100644 --- a/net/openvswitch/vport.c +++ b/net/openvswitch/vport.c @@ -407,6 +407,9 @@ int ovs_vport_set_upcall_portids(struct vport *vport, const struct nlattr *ids) if (!nla_len(ids) || nla_len(ids) % sizeof(u32)) return -EINVAL; + if (nla_len(ids) / sizeof(u32) > nr_cpu_ids) + return -EINVAL; + old = ovsl_dereference(vport->upcall_portids); vport_portids = kmalloc(sizeof(*vport_portids) + nla_len(ids), -- 2.53.0