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: <LOOPBACK,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,M-DOWN> 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: <BROADCAST,MULTICAST,M-DOWN> 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 <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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;
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;
int rtnl_configure_link(struct net_device *dev, const struct ifinfomsg *ifm,
u32 portid, const struct nlmsghdr *nlh);
-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)
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[])
{