cmd/tailscale: don't allow setting exit node to known invalid value

Fixes #3081

Change-Id: I34c378dfd51ee013c21962dbe79c49b1ba06c0c5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/3489/head
Brad Fitzpatrick 3 years ago committed by Brad Fitzpatrick
parent a8f60cf6e8
commit 03a323de4e

@ -852,9 +852,47 @@ func TestExitNodeIPOfArg(t *testing.T) {
want netaddr.IP
wantErr string
}{
{
name: "ip_while_stopped_okay",
arg: "1.2.3.4",
st: &ipnstate.Status{
BackendState: "Stopped",
},
want: mustIP("1.2.3.4"),
},
{
name: "ip_not_found",
arg: "1.2.3.4",
st: &ipnstate.Status{
BackendState: "Running",
},
wantErr: `no node found in netmap with IP 1.2.3.4`,
},
{
name: "ip_not_exit",
arg: "1.2.3.4",
st: &ipnstate.Status{
BackendState: "Running",
Peer: map[key.NodePublic]*ipnstate.PeerStatus{
key.NewNode().Public(): {
TailscaleIPs: []netaddr.IP{mustIP("1.2.3.4")},
},
},
},
wantErr: `node 1.2.3.4 is not advertising an exit node`,
},
{
name: "ip",
arg: "1.2.3.4",
st: &ipnstate.Status{
BackendState: "Running",
Peer: map[key.NodePublic]*ipnstate.PeerStatus{
key.NewNode().Public(): {
TailscaleIPs: []netaddr.IP{mustIP("1.2.3.4")},
ExitNodeOption: true,
},
},
},
want: mustIP("1.2.3.4"),
},
{
@ -870,15 +908,16 @@ func TestExitNodeIPOfArg(t *testing.T) {
MagicDNSSuffix: ".foo",
Peer: map[key.NodePublic]*ipnstate.PeerStatus{
key.NewNode().Public(): {
DNSName: "skippy.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
DNSName: "skippy.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
ExitNodeOption: true,
},
},
},
want: mustIP("1.0.0.2"),
},
{
name: "ambiguous",
name: "name_not_exit",
arg: "skippy",
st: &ipnstate.Status{
MagicDNSSuffix: ".foo",
@ -887,9 +926,25 @@ func TestExitNodeIPOfArg(t *testing.T) {
DNSName: "skippy.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
},
},
},
wantErr: `node "skippy" is not advertising an exit node`,
},
{
name: "ambiguous",
arg: "skippy",
st: &ipnstate.Status{
MagicDNSSuffix: ".foo",
Peer: map[key.NodePublic]*ipnstate.PeerStatus{
key.NewNode().Public(): {
DNSName: "skippy.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
ExitNodeOption: true,
},
key.NewNode().Public(): {
DNSName: "SKIPPY.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
DNSName: "SKIPPY.foo.",
TailscaleIPs: []netaddr.IP{mustIP("1.0.0.2")},
ExitNodeOption: true,
},
},
},

@ -193,12 +193,38 @@ func calcAdvertiseRoutes(advertiseRoutes string, advertiseDefaultRoute bool) ([]
return routes, nil
}
// peerWithTailscaleIP returns the peer in st with the provided
// Tailscale IP.
func peerWithTailscaleIP(st *ipnstate.Status, ip netaddr.IP) (ps *ipnstate.PeerStatus, ok bool) {
for _, ps := range st.Peer {
for _, ip2 := range ps.TailscaleIPs {
if ip == ip2 {
return ps, true
}
}
}
return nil, false
}
// exitNodeIPOfArg maps from a user-provided CLI flag value to an IP
// address they want to use as an exit node.
func exitNodeIPOfArg(arg string, st *ipnstate.Status) (ip netaddr.IP, err error) {
if arg == "" {
return ip, errors.New("invalid use of exitNodeIPOfArg with empty string")
}
ip, err = netaddr.ParseIP(arg)
if err == nil {
// If we're online already and have a netmap, double check that the IP
// address specified is valid.
if st.BackendState == "Running" {
ps, ok := peerWithTailscaleIP(st, ip)
if !ok {
return ip, fmt.Errorf("no node found in netmap with IP %v", ip)
}
if !ps.ExitNodeOption {
return ip, fmt.Errorf("node %v is not advertising an exit node", ip)
}
}
return ip, err
}
match := 0
@ -211,6 +237,9 @@ func exitNodeIPOfArg(arg string, st *ipnstate.Status) (ip netaddr.IP, err error)
if len(ps.TailscaleIPs) == 0 {
return ip, fmt.Errorf("node %q has no Tailscale IP?", arg)
}
if !ps.ExitNodeOption {
return ip, fmt.Errorf("node %q is not advertising an exit node", arg)
}
ip = ps.TailscaleIPs[0]
}
switch match {

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