github.com/mtsmfm/go/src@v0.0.0-20221020090648-44bdcb9f8fde/os/exec/lp_linux_test.go (about)

     1  // Copyright 2022 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  package exec
     6  
     7  import (
     8  	"internal/syscall/unix"
     9  	"os"
    10  	"path/filepath"
    11  	"syscall"
    12  	"testing"
    13  )
    14  
    15  func TestFindExecutableVsNoexec(t *testing.T) {
    16  	t.Parallel()
    17  
    18  	// This test case relies on faccessat2(2) syscall, which appeared in Linux v5.8.
    19  	if major, minor := unix.KernelVersion(); major < 5 || (major == 5 && minor < 8) {
    20  		t.Skip("requires Linux kernel v5.8 with faccessat2(2) syscall")
    21  	}
    22  
    23  	tmp := t.TempDir()
    24  
    25  	// Create a tmpfs mount.
    26  	err := syscall.Mount("tmpfs", tmp, "tmpfs", 0, "")
    27  	if err != nil {
    28  		// Usually this means lack of CAP_SYS_ADMIN, but there might be
    29  		// other reasons, especially in restricted test environments.
    30  		t.Skipf("requires ability to mount tmpfs (%v)", err)
    31  	}
    32  	t.Cleanup(func() {
    33  		if err := syscall.Unmount(tmp, 0); err != nil {
    34  			t.Error(err)
    35  		}
    36  	})
    37  
    38  	// Create an executable.
    39  	path := filepath.Join(tmp, "program")
    40  	err = os.WriteFile(path, []byte("#!/bin/sh\necho 123\n"), 0o755)
    41  	if err != nil {
    42  		t.Fatal(err)
    43  	}
    44  
    45  	// Check that it works as expected.
    46  	err = findExecutable(path)
    47  	if err != nil {
    48  		t.Fatalf("findExecutable: got %v, want nil", err)
    49  	}
    50  
    51  	if err := Command(path).Run(); err != nil {
    52  		t.Fatalf("exec: got %v, want nil", err)
    53  	}
    54  
    55  	// Remount with noexec flag.
    56  	err = syscall.Mount("", tmp, "", syscall.MS_REMOUNT|syscall.MS_NOEXEC, "")
    57  	if err != nil {
    58  		t.Fatalf("remount %s with noexec failed: %v", tmp, err)
    59  	}
    60  
    61  	if err := Command(path).Run(); err == nil {
    62  		t.Fatal("exec on noexec filesystem: got nil, want error")
    63  	}
    64  
    65  	err = findExecutable(path)
    66  	if err == nil {
    67  		t.Fatalf("findExecutable: got nil, want error")
    68  	}
    69  }