tailscale/wgengine/netstack/netstack_userping.go
Andrea Gottardo e5f67f90a2
xcode: allow ICMP ping relay on macOS + iOS platforms (#12048)
Fixes tailscale/tailscale#10393
Fixes tailscale/corp#15412
Fixes tailscale/corp#19808

On Apple platforms, exit nodes and subnet routers have been unable to relay pings from Tailscale devices to non-Tailscale devices due to sandbox restrictions imposed on our network extensions by Apple. The sandbox prevented the code in netstack.go from spawning the `ping` process which we were using.

Replace that exec call with logic to send an ICMP echo request directly, which appears to work in userspace, and not trigger a sandbox violation in the syslog.

Signed-off-by: Andrea Gottardo <andrea@gottardo.me>
2024-05-16 11:57:57 -07:00

66 lines
1.7 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build !darwin && !ios
package netstack
import (
"net/netip"
"os"
"os/exec"
"runtime"
"time"
"tailscale.com/version/distro"
)
// setAmbientCapsRaw is non-nil on Linux for Synology, to run ping with
// CAP_NET_RAW from tailscaled's binary.
var setAmbientCapsRaw func(*exec.Cmd)
var isSynology = runtime.GOOS == "linux" && distro.Get() == distro.Synology
// sendOutboundUserPing sends a non-privileged ICMP (or ICMPv6) ping to dstIP with the given timeout.
func (ns *Impl) sendOutboundUserPing(dstIP netip.Addr, timeout time.Duration) error {
var err error
switch runtime.GOOS {
case "windows":
err = exec.Command("ping", "-n", "1", "-w", "3000", dstIP.String()).Run()
case "freebsd":
// Note: 2000 ms is actually 1 second + 2,000
// milliseconds extra for 3 seconds total.
// See https://github.com/tailscale/tailscale/pull/3753 for details.
ping := "ping"
if dstIP.Is6() {
ping = "ping6"
}
err = exec.Command(ping, "-c", "1", "-W", "2000", dstIP.String()).Run()
case "openbsd":
ping := "ping"
if dstIP.Is6() {
ping = "ping6"
}
err = exec.Command(ping, "-c", "1", "-w", "3", dstIP.String()).Run()
case "android":
ping := "/system/bin/ping"
if dstIP.Is6() {
ping = "/system/bin/ping6"
}
err = exec.Command(ping, "-c", "1", "-w", "3", dstIP.String()).Run()
default:
ping := "ping"
if isSynology {
ping = "/bin/ping"
}
cmd := exec.Command(ping, "-c", "1", "-W", "3", dstIP.String())
if isSynology && os.Getuid() != 0 {
// On DSM7 we run as non-root and need to pass
// CAP_NET_RAW if our binary has it.
setAmbientCapsRaw(cmd)
}
err = cmd.Run()
}
return err
}