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 03DCD11C8D for ; Mon, 28 Aug 2023 10:31:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75E62C433C7; Mon, 28 Aug 2023 10:31:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693218667; bh=8h/nWeH79EWD2Sn/DcNqH8wvxNG5fm5Jdu6QjDaN0Hc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dXCXgdqi6DxzNPYGOEt2Num6JF0ZvcXBcfbywEFHvT5gNshQnk0oz8niLprXUcrf/ velKbzC+HG7FJfCR69RV549XEWh1zAT3kslob4LPup7ifo/tsdDGR1/2pAj+xfENZD hiBLuGxvEPbxe6DcuoYp9qigICGlZgsLxnmnAsLM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+5ba06978f34abb058571@syzkaller.appspotmail.com, Jakub Kicinski , Eric Dumazet , "David S. Miller" , Sasha Levin Subject: [PATCH 6.1 040/122] net: validate veth and vxcan peer ifindexes Date: Mon, 28 Aug 2023 12:12:35 +0200 Message-ID: <20230828101157.735520597@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101156.480754469@linuxfoundation.org> References: <20230828101156.480754469@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit f534f6581ec084fe94d6759f7672bd009794b07e ] veth and vxcan need to make sure the ifindexes of the peer are not negative, core does not validate this. Using iproute2 with user-space-level checking removed: Before: # ./ip link add index 10 type veth peer index -1 # ip link show 1: lo: mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: enp1s0: mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:74:b2:03 brd ff:ff:ff:ff:ff:ff 10: veth1@veth0: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 8a:90:ff:57:6d:5d brd ff:ff:ff:ff:ff:ff -1: veth0@veth1: mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether ae:ed:18:e6:fa:7f brd ff:ff:ff:ff:ff:ff Now: $ ./ip link add index 10 type veth peer index -1 Error: ifindex can't be negative. This problem surfaced in net-next because an explicit WARN() was added, the root cause is older. Fixes: e6f8f1a739b6 ("veth: Allow to create peer link with given ifindex") Fixes: a8f820a380a2 ("can: add Virtual CAN Tunnel driver (vxcan)") Reported-by: syzbot+5ba06978f34abb058571@syzkaller.appspotmail.com Signed-off-by: Jakub Kicinski Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/can/vxcan.c | 7 +------ drivers/net/veth.c | 5 +---- include/net/rtnetlink.h | 4 ++-- net/core/rtnetlink.c | 22 ++++++++++++++++++---- 4 files changed, 22 insertions(+), 16 deletions(-) diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c index 26a472d2ea583..6d549dbdb4674 100644 --- a/drivers/net/can/vxcan.c +++ b/drivers/net/can/vxcan.c @@ -192,12 +192,7 @@ static int vxcan_newlink(struct net *net, struct net_device *dev, nla_peer = data[VXCAN_INFO_PEER]; ifmp = nla_data(nla_peer); - err = rtnl_nla_parse_ifla(peer_tb, - nla_data(nla_peer) + - sizeof(struct ifinfomsg), - nla_len(nla_peer) - - sizeof(struct ifinfomsg), - NULL); + err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); if (err < 0) return err; diff --git a/drivers/net/veth.c b/drivers/net/veth.c index a71786b3e7ba7..727b9278b9fe5 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1716,10 +1716,7 @@ static int veth_newlink(struct net *src_net, struct net_device *dev, nla_peer = data[VETH_INFO_PEER]; ifmp = nla_data(nla_peer); - err = rtnl_nla_parse_ifla(peer_tb, - nla_data(nla_peer) + sizeof(struct ifinfomsg), - nla_len(nla_peer) - sizeof(struct ifinfomsg), - NULL); + err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); if (err < 0) return err; diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index bf8bb33578250..9f881b74f32ed 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -189,8 +189,8 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname, int rtnl_delete_link(struct net_device *dev); int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm); -int rtnl_nla_parse_ifla(struct nlattr **tb, const struct nlattr *head, int len, - struct netlink_ext_ack *exterr); +int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, + struct netlink_ext_ack *exterr); struct net *rtnl_get_net_ns_capable(struct sock *sk, int netnsid); #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 2758b3f7c0214..48e300a144ad6 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2220,13 +2220,27 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) return err; } -int rtnl_nla_parse_ifla(struct nlattr **tb, const struct nlattr *head, int len, - struct netlink_ext_ack *exterr) +int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, + struct netlink_ext_ack *exterr) { - return nla_parse_deprecated(tb, IFLA_MAX, head, len, ifla_policy, + const struct ifinfomsg *ifmp; + const struct nlattr *attrs; + size_t len; + + ifmp = nla_data(nla_peer); + attrs = nla_data(nla_peer) + sizeof(struct ifinfomsg); + len = nla_len(nla_peer) - sizeof(struct ifinfomsg); + + if (ifmp->ifi_index < 0) { + NL_SET_ERR_MSG_ATTR(exterr, nla_peer, + "ifindex can't be negative"); + return -EINVAL; + } + + return nla_parse_deprecated(tb, IFLA_MAX, attrs, len, ifla_policy, exterr); } -EXPORT_SYMBOL(rtnl_nla_parse_ifla); +EXPORT_SYMBOL(rtnl_nla_parse_ifinfomsg); struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]) { -- 2.40.1