github.com/zebozhuang/go@v0.0.0-20200207033046-f8a98f6f5c5d/src/syscall/creds_test.go (about)

     1  // Copyright 2012 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  // +build linux
     6  
     7  package syscall_test
     8  
     9  import (
    10  	"bytes"
    11  	"net"
    12  	"os"
    13  	"syscall"
    14  	"testing"
    15  )
    16  
    17  // TestSCMCredentials tests the sending and receiving of credentials
    18  // (PID, UID, GID) in an ancillary message between two UNIX
    19  // sockets. The SO_PASSCRED socket option is enabled on the sending
    20  // socket for this to work.
    21  func TestSCMCredentials(t *testing.T) {
    22  	fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
    23  	if err != nil {
    24  		t.Fatalf("Socketpair: %v", err)
    25  	}
    26  	defer syscall.Close(fds[0])
    27  	defer syscall.Close(fds[1])
    28  
    29  	err = syscall.SetsockoptInt(fds[0], syscall.SOL_SOCKET, syscall.SO_PASSCRED, 1)
    30  	if err != nil {
    31  		t.Fatalf("SetsockoptInt: %v", err)
    32  	}
    33  
    34  	srvFile := os.NewFile(uintptr(fds[0]), "server")
    35  	defer srvFile.Close()
    36  	srv, err := net.FileConn(srvFile)
    37  	if err != nil {
    38  		t.Errorf("FileConn: %v", err)
    39  		return
    40  	}
    41  	defer srv.Close()
    42  
    43  	cliFile := os.NewFile(uintptr(fds[1]), "client")
    44  	defer cliFile.Close()
    45  	cli, err := net.FileConn(cliFile)
    46  	if err != nil {
    47  		t.Errorf("FileConn: %v", err)
    48  		return
    49  	}
    50  	defer cli.Close()
    51  
    52  	var ucred syscall.Ucred
    53  	if os.Getuid() != 0 {
    54  		ucred.Pid = int32(os.Getpid())
    55  		ucred.Uid = 0
    56  		ucred.Gid = 0
    57  		oob := syscall.UnixCredentials(&ucred)
    58  		_, _, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
    59  		if op, ok := err.(*net.OpError); ok {
    60  			err = op.Err
    61  		}
    62  		if sys, ok := err.(*os.SyscallError); ok {
    63  			err = sys.Err
    64  		}
    65  		if err != syscall.EPERM {
    66  			t.Fatalf("WriteMsgUnix failed with %v, want EPERM", err)
    67  		}
    68  	}
    69  
    70  	ucred.Pid = int32(os.Getpid())
    71  	ucred.Uid = uint32(os.Getuid())
    72  	ucred.Gid = uint32(os.Getgid())
    73  	oob := syscall.UnixCredentials(&ucred)
    74  
    75  	// this is going to send a dummy byte
    76  	n, oobn, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
    77  	if err != nil {
    78  		t.Fatalf("WriteMsgUnix: %v", err)
    79  	}
    80  	if n != 0 {
    81  		t.Fatalf("WriteMsgUnix n = %d, want 0", n)
    82  	}
    83  	if oobn != len(oob) {
    84  		t.Fatalf("WriteMsgUnix oobn = %d, want %d", oobn, len(oob))
    85  	}
    86  
    87  	oob2 := make([]byte, 10*len(oob))
    88  	n, oobn2, flags, _, err := srv.(*net.UnixConn).ReadMsgUnix(nil, oob2)
    89  	if err != nil {
    90  		t.Fatalf("ReadMsgUnix: %v", err)
    91  	}
    92  	if flags != 0 {
    93  		t.Fatalf("ReadMsgUnix flags = 0x%x, want 0", flags)
    94  	}
    95  	if n != 1 {
    96  		t.Fatalf("ReadMsgUnix n = %d, want 1 (dummy byte)", n)
    97  	}
    98  	if oobn2 != oobn {
    99  		// without SO_PASSCRED set on the socket, ReadMsgUnix will
   100  		// return zero oob bytes
   101  		t.Fatalf("ReadMsgUnix oobn = %d, want %d", oobn2, oobn)
   102  	}
   103  	oob2 = oob2[:oobn2]
   104  	if !bytes.Equal(oob, oob2) {
   105  		t.Fatal("ReadMsgUnix oob bytes don't match")
   106  	}
   107  
   108  	scm, err := syscall.ParseSocketControlMessage(oob2)
   109  	if err != nil {
   110  		t.Fatalf("ParseSocketControlMessage: %v", err)
   111  	}
   112  	newUcred, err := syscall.ParseUnixCredentials(&scm[0])
   113  	if err != nil {
   114  		t.Fatalf("ParseUnixCredentials: %v", err)
   115  	}
   116  	if *newUcred != ucred {
   117  		t.Fatalf("ParseUnixCredentials = %+v, want %+v", newUcred, ucred)
   118  	}
   119  }