From 4af1fe642f3724f1567e7c2017eeb857b08399d6 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 18 Aug 2023 18:26:02 -0700 Subject: net: validate veth and vxcan peer ifindexes [ 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 +---- 2 files changed, 2 insertions(+), 10 deletions(-) (limited to 'drivers') diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c index 26a472d2ea58..6d549dbdb467 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 a71786b3e7ba..727b9278b9fe 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; -- cgit v1.2.3