exec_windows_test.go

Documentation: internal/syscall/windows

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build windows
     6  
     7  package windows_test
     8  
     9  import (
    10  	"fmt"
    11  	"internal/syscall/windows"
    12  	"os"
    13  	"os/exec"
    14  	"syscall"
    15  	"testing"
    16  	"unsafe"
    17  )
    18  
    19  func TestRunAtLowIntegrity(t *testing.T) {
    20  	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
    21  		wil, err := getProcessIntegrityLevel()
    22  		if err != nil {
    23  			fmt.Fprintf(os.Stderr, "error: %s\n", err.Error())
    24  			os.Exit(9)
    25  			return
    26  		}
    27  		fmt.Printf("%s", wil)
    28  		os.Exit(0)
    29  		return
    30  	}
    31  
    32  	cmd := exec.Command(os.Args[0], "-test.run=^TestRunAtLowIntegrity$", "--")
    33  	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
    34  
    35  	token, err := getIntegrityLevelToken(sidWilLow)
    36  	if err != nil {
    37  		t.Fatal(err)
    38  	}
    39  	defer token.Close()
    40  
    41  	cmd.SysProcAttr = &syscall.SysProcAttr{
    42  		Token: token,
    43  	}
    44  
    45  	out, err := cmd.CombinedOutput()
    46  	if err != nil {
    47  		t.Fatal(err)
    48  	}
    49  
    50  	if string(out) != sidWilLow {
    51  		t.Fatalf("Child process did not run as low integrity level: %s", string(out))
    52  	}
    53  }
    54  
    55  const (
    56  	sidWilLow = `S-1-16-4096`
    57  )
    58  
    59  func getProcessIntegrityLevel() (string, error) {
    60  	procToken, err := syscall.OpenCurrentProcessToken()
    61  	if err != nil {
    62  		return "", err
    63  	}
    64  	defer procToken.Close()
    65  
    66  	p, err := tokenGetInfo(procToken, syscall.TokenIntegrityLevel, 64)
    67  	if err != nil {
    68  		return "", err
    69  	}
    70  
    71  	tml := (*windows.TOKEN_MANDATORY_LABEL)(p)
    72  
    73  	sid := (*syscall.SID)(unsafe.Pointer(tml.Label.Sid))
    74  
    75  	return sid.String()
    76  }
    77  
    78  func tokenGetInfo(t syscall.Token, class uint32, initSize int) (unsafe.Pointer, error) {
    79  	n := uint32(initSize)
    80  	for {
    81  		b := make([]byte, n)
    82  		e := syscall.GetTokenInformation(t, class, &b[0], uint32(len(b)), &n)
    83  		if e == nil {
    84  			return unsafe.Pointer(&b[0]), nil
    85  		}
    86  		if e != syscall.ERROR_INSUFFICIENT_BUFFER {
    87  			return nil, e
    88  		}
    89  		if n <= uint32(len(b)) {
    90  			return nil, e
    91  		}
    92  	}
    93  }
    94  
    95  func getIntegrityLevelToken(wns string) (syscall.Token, error) {
    96  	var procToken, token syscall.Token
    97  
    98  	proc, err := syscall.GetCurrentProcess()
    99  	if err != nil {
   100  		return 0, err
   101  	}
   102  	defer syscall.CloseHandle(proc)
   103  
   104  	err = syscall.OpenProcessToken(proc,
   105  		syscall.TOKEN_DUPLICATE|
   106  			syscall.TOKEN_ADJUST_DEFAULT|
   107  			syscall.TOKEN_QUERY|
   108  			syscall.TOKEN_ASSIGN_PRIMARY,
   109  		&procToken)
   110  	if err != nil {
   111  		return 0, err
   112  	}
   113  	defer procToken.Close()
   114  
   115  	sid, err := syscall.StringToSid(wns)
   116  	if err != nil {
   117  		return 0, err
   118  	}
   119  
   120  	tml := &windows.TOKEN_MANDATORY_LABEL{}
   121  	tml.Label.Attributes = windows.SE_GROUP_INTEGRITY
   122  	tml.Label.Sid = sid
   123  
   124  	err = windows.DuplicateTokenEx(procToken, 0, nil, windows.SecurityImpersonation,
   125  		windows.TokenPrimary, &token)
   126  	if err != nil {
   127  		return 0, err
   128  	}
   129  
   130  	err = windows.SetTokenInformation(token,
   131  		syscall.TokenIntegrityLevel,
   132  		uintptr(unsafe.Pointer(tml)),
   133  		tml.Size())
   134  	if err != nil {
   135  		token.Close()
   136  		return 0, err
   137  	}
   138  	return token, nil
   139  }
   140
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