50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !js && !windows
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package cli
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import (
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"bytes"
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"os"
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"path/filepath"
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"runtime"
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"strconv"
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"golang.org/x/sys/unix"
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)
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func init() {
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getSSHClientEnvVar = func() string {
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if os.Getenv("SUDO_USER") == "" {
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// No sudo, just check the env.
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return os.Getenv("SSH_CLIENT")
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}
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if runtime.GOOS != "linux" {
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// TODO(maisem): implement this for other platforms. It's not clear
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// if there is a way to get the environment for a given process on
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// darwin and bsd.
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return ""
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}
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// SID is the session ID of the user's login session.
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// It is also the process ID of the original shell that the user logged in with.
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// We only need to check the environment of that process.
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sid, err := unix.Getsid(os.Getpid())
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if err != nil {
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return ""
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}
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b, err := os.ReadFile(filepath.Join("/proc", strconv.Itoa(sid), "environ"))
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if err != nil {
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return ""
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}
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prefix := []byte("SSH_CLIENT=")
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for _, env := range bytes.Split(b, []byte{0}) {
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if bytes.HasPrefix(env, prefix) {
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return string(env[len(prefix):])
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}
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}
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return ""
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}
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}
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