From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ju.orth@gmail.com Received: from krantz.zx2c4.com (localhost [127.0.0.1]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 982dbb96 for ; Tue, 11 Sep 2018 19:12:38 +0000 (UTC) Received: from mail-wm0-x241.google.com (mail-wm0-x241.google.com [IPv6:2a00:1450:400c:c09::241]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 5c9be1d2 for ; Tue, 11 Sep 2018 19:12:37 +0000 (UTC) Received: by mail-wm0-x241.google.com with SMTP id y139-v6so2142546wmc.2 for ; Tue, 11 Sep 2018 12:13:30 -0700 (PDT) Return-Path: From: Julian Orth To: wireguard@lists.zx2c4.com Subject: [PATCH v3 03/12] netlink: allow specifying the device namespace Date: Tue, 11 Sep 2018 21:13:02 +0200 Message-Id: <20180911191311.25373-4-ju.orth@gmail.com> In-Reply-To: <20180911191311.25373-1-ju.orth@gmail.com> References: <20180911191311.25373-1-ju.orth@gmail.com> List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This commit adds two new attributes of which at most one may be provided: * WGDEVICE_A_DEV_NETNS_PID: NLA_U32 * WGDEVICE_A_DEV_NETNS_FD: NLA_U32 The Wireguard device is then looked up in this namespace instead of the namespace of the netlink socket. --- src/netlink.c | 82 ++++++++++++++++++++++++++++++++++---------- src/uapi/wireguard.h | 26 ++++++++++++-- 2 files changed, 87 insertions(+), 21 deletions(-) diff --git a/src/netlink.c b/src/netlink.c index a857aff..19fe92d 100644 --- a/src/netlink.c +++ b/src/netlink.c @@ -24,7 +24,9 @@ static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = { [WGDEVICE_A_FLAGS] = { .type = NLA_U32 }, [WGDEVICE_A_LISTEN_PORT] = { .type = NLA_U16 }, [WGDEVICE_A_FWMARK] = { .type = NLA_U32 }, - [WGDEVICE_A_PEERS] = { .type = NLA_NESTED } + [WGDEVICE_A_PEERS] = { .type = NLA_NESTED }, + [WGDEVICE_A_DEV_NETNS_PID] = { .type = NLA_U32 }, + [WGDEVICE_A_DEV_NETNS_FD] = { .type = NLA_U32 }, }; static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = { @@ -47,17 +49,17 @@ static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1] = { }; static struct wireguard_device *lookup_interface(struct nlattr **attrs, - struct sk_buff *skb) + struct net *net) { struct net_device *dev = NULL; if (!attrs[WGDEVICE_A_IFINDEX] == !attrs[WGDEVICE_A_IFNAME]) return ERR_PTR(-EBADR); if (attrs[WGDEVICE_A_IFINDEX]) - dev = dev_get_by_index(sock_net(skb->sk), + dev = dev_get_by_index(net, nla_get_u32(attrs[WGDEVICE_A_IFINDEX])); else if (attrs[WGDEVICE_A_IFNAME]) - dev = dev_get_by_name(sock_net(skb->sk), + dev = dev_get_by_name(net, nla_data(attrs[WGDEVICE_A_IFNAME])); if (!dev) return ERR_PTR(-ENODEV); @@ -166,30 +168,64 @@ err: return -EMSGSIZE; } +static struct net *get_attr_net(struct nlattr *net_pid, struct nlattr *net_fd) +{ + if (net_pid && net_fd) + return ERR_PTR(-EINVAL); + if (net_pid) + return get_net_ns_by_pid(nla_get_u32(net_pid)); + if (net_fd) + return get_net_ns_by_fd(nla_get_u32(net_fd)); + return NULL; +} + static int get_device_start(struct netlink_callback *cb) { struct nlattr **attrs = genl_family_attrbuf(&genl_family); int ret = nlmsg_parse(cb->nlh, GENL_HDRLEN + genl_family.hdrsize, attrs, genl_family.maxattr, device_policy, NULL); struct wireguard_device *wg; - struct net *dev_net = sock_net(cb->skb->sk); + struct net *owned_dev_net = NULL, *dev_net; + struct allowedips_cursor *cursor = NULL; if (ret < 0) return ret; - if (!netlink_ns_capable(cb->skb, dev_net->user_ns, CAP_NET_ADMIN)) - return -EPERM; - cb->args[2] = (long)kzalloc(sizeof(struct allowedips_cursor), - GFP_KERNEL); - if (unlikely(!cb->args[2])) - return -ENOMEM; - wg = lookup_interface(attrs, cb->skb); + + owned_dev_net = get_attr_net(attrs[WGDEVICE_A_DEV_NETNS_PID], + attrs[WGDEVICE_A_DEV_NETNS_FD]); + if (IS_ERR(owned_dev_net)) { + ret = PTR_ERR(owned_dev_net); + owned_dev_net = NULL; + goto out; + } + dev_net = owned_dev_net ? : sock_net(cb->skb->sk); + if (!netlink_ns_capable(cb->skb, dev_net->user_ns, CAP_NET_ADMIN)) { + ret = -EPERM; + goto out; + } + + cursor = kzalloc(sizeof(*cursor), GFP_KERNEL); + if (unlikely(!cursor)) { + ret = -ENOMEM; + goto out; + } + + wg = lookup_interface(attrs, dev_net); if (IS_ERR(wg)) { - kfree((void *)cb->args[2]); - cb->args[2] = 0; - return PTR_ERR(wg); + ret = PTR_ERR(wg); + goto out; } + cb->args[0] = (long)wg; - return 0; + cb->args[2] = (long)cursor; + cursor = NULL; + +out: + if (cursor) + kfree(cursor); + if (owned_dev_net) + put_net(owned_dev_net); + return ret; } static int get_device_dump(struct sk_buff *skb, struct netlink_callback *cb) @@ -481,14 +517,21 @@ static int set_device(struct sk_buff *skb, struct genl_info *info) { int ret; struct wireguard_device *wg; - struct net *dev_net = sock_net(skb->sk); + struct net *owned_dev_net, *dev_net; + owned_dev_net = get_attr_net(info->attrs[WGDEVICE_A_DEV_NETNS_PID], + info->attrs[WGDEVICE_A_DEV_NETNS_FD]); + if (IS_ERR(owned_dev_net)) { + ret = PTR_ERR(wg); + goto out_nonet; + } + dev_net = owned_dev_net ? : sock_net(skb->sk); if (!netlink_ns_capable(skb, dev_net->user_ns, CAP_NET_ADMIN)) { ret = -EPERM; goto out_nodev; } - wg = lookup_interface(info->attrs, skb); + wg = lookup_interface(info->attrs, dev_net); if (IS_ERR(wg)) { ret = PTR_ERR(wg); @@ -571,6 +614,9 @@ out: rtnl_unlock(); dev_put(wg->dev); out_nodev: + if (owned_dev_net) + put_net(owned_dev_net); +out_nonet: if (info->attrs[WGDEVICE_A_PRIVATE_KEY]) memzero_explicit(nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]), nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY])); diff --git a/src/uapi/wireguard.h b/src/uapi/wireguard.h index 3d73ad7..cff46f9 100644 --- a/src/uapi/wireguard.h +++ b/src/uapi/wireguard.h @@ -20,6 +20,16 @@ * WGDEVICE_A_IFINDEX: NLA_U32 * WGDEVICE_A_IFNAME: NLA_NUL_STRING, maxlen IFNAMESIZ - 1 * + * At most one of the following may be provided: + * + * WGDEVICE_A_DEV_NETNS_PID: NLA_U32 + * WGDEVICE_A_DEV_NETNS_FD: NLA_U32 + * + * If they are provided, the Wireguard device will be looked up in this network + * namespace. Otherwise it is looked up in the network namespace of the netlink + * socket. The caller must have CAP_NET_ADMIN in the namespace of the Wireguard + * device. + * * The kernel will then return several messages (NLM_F_MULTI) containing the * following tree of nested items: * @@ -72,9 +82,15 @@ * WG_CMD_SET_DEVICE * ----------------- * - * May only be called via NLM_F_REQUEST. The command should contain the - * following tree of nested items, containing one but not both of - * WGDEVICE_A_IFINDEX and WGDEVICE_A_IFNAME: + * May only be called via NLM_F_REQUEST. The command must contain the following + * tree of nested items. Exactly one of WGDEVICE_A_IFINDEX and WGDEVICE_A_IFNAME + * must be provided. All other top-level items are optional. At most one of + * WGDEVICE_A_DEV_NETNS_PID and WGDEVICE_A_DEV_NETNS_FD may be provided. + * + * If WGDEVICE_A_DEV_NETNS_PID/FD is provided, the Wireguard device is looked up + * in this network namespace. Otherwise it is looked up in the network namespace + * of the netlink socket. The caller must have CAP_NET_ADMIN in the namespace of + * the Wireguard device. * * WGDEVICE_A_IFINDEX: NLA_U32 * WGDEVICE_A_IFNAME: NLA_NUL_STRING, maxlen IFNAMESIZ - 1 @@ -82,6 +98,8 @@ * peers should be removed prior to adding the list below. * WGDEVICE_A_PRIVATE_KEY: len WG_KEY_LEN, all zeros to remove * WGDEVICE_A_LISTEN_PORT: NLA_U16, 0 to choose randomly + * WGDEVICE_A_DEV_NETNS_PID: NLA_U32 + * WGDEVICE_A_DEV_NETNS_FD: NLA_U32 * WGDEVICE_A_FWMARK: NLA_U32, 0 to disable * WGDEVICE_A_PEERS: NLA_NESTED * 0: NLA_NESTED @@ -154,6 +172,8 @@ enum wgdevice_attribute { WGDEVICE_A_LISTEN_PORT, WGDEVICE_A_FWMARK, WGDEVICE_A_PEERS, + WGDEVICE_A_DEV_NETNS_PID, + WGDEVICE_A_DEV_NETNS_FD, __WGDEVICE_A_LAST }; #define WGDEVICE_A_MAX (__WGDEVICE_A_LAST - 1) -- 2.18.0