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 } 120
