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 socketTypeTests := []struct { 23 socketType int 24 dataLen int 25 }{ 26 { 27 syscall.SOCK_STREAM, 28 1, 29 }, { 30 syscall.SOCK_DGRAM, 31 0, 32 }, 33 } 34 35 for _, tt := range socketTypeTests { 36 fds, err := syscall.Socketpair(syscall.AF_LOCAL, tt.socketType, 0) 37 if err != nil { 38 t.Fatalf("Socketpair: %v", err) 39 } 40 defer syscall.Close(fds[0]) 41 defer syscall.Close(fds[1]) 42 43 err = syscall.SetsockoptInt(fds[0], syscall.SOL_SOCKET, syscall.SO_PASSCRED, 1) 44 if err != nil { 45 t.Fatalf("SetsockoptInt: %v", err) 46 } 47 48 srvFile := os.NewFile(uintptr(fds[0]), "server") 49 defer srvFile.Close() 50 srv, err := net.FileConn(srvFile) 51 if err != nil { 52 t.Errorf("FileConn: %v", err) 53 return 54 } 55 defer srv.Close() 56 57 cliFile := os.NewFile(uintptr(fds[1]), "client") 58 defer cliFile.Close() 59 cli, err := net.FileConn(cliFile) 60 if err != nil { 61 t.Errorf("FileConn: %v", err) 62 return 63 } 64 defer cli.Close() 65 66 var ucred syscall.Ucred 67 if os.Getuid() != 0 { 68 ucred.Pid = int32(os.Getpid()) 69 ucred.Uid = 0 70 ucred.Gid = 0 71 oob := syscall.UnixCredentials(&ucred) 72 _, _, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil) 73 if op, ok := err.(*net.OpError); ok { 74 err = op.Err 75 } 76 if sys, ok := err.(*os.SyscallError); ok { 77 err = sys.Err 78 } 79 if err != syscall.EPERM { 80 t.Fatalf("WriteMsgUnix failed with %v, want EPERM", err) 81 } 82 } 83 84 ucred.Pid = int32(os.Getpid()) 85 ucred.Uid = uint32(os.Getuid()) 86 ucred.Gid = uint32(os.Getgid()) 87 oob := syscall.UnixCredentials(&ucred) 88 89 // On SOCK_STREAM, this is internally going to send a dummy byte 90 n, oobn, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil) 91 if err != nil { 92 t.Fatalf("WriteMsgUnix: %v", err) 93 } 94 if n != 0 { 95 t.Fatalf("WriteMsgUnix n = %d, want 0", n) 96 } 97 if oobn != len(oob) { 98 t.Fatalf("WriteMsgUnix oobn = %d, want %d", oobn, len(oob)) 99 } 100 101 oob2 := make([]byte, 10*len(oob)) 102 n, oobn2, flags, _, err := srv.(*net.UnixConn).ReadMsgUnix(nil, oob2) 103 if err != nil { 104 t.Fatalf("ReadMsgUnix: %v", err) 105 } 106 if flags != 0 { 107 t.Fatalf("ReadMsgUnix flags = 0x%x, want 0", flags) 108 } 109 if n != tt.dataLen { 110 t.Fatalf("ReadMsgUnix n = %d, want %d", n, tt.dataLen) 111 } 112 if oobn2 != oobn { 113 // without SO_PASSCRED set on the socket, ReadMsgUnix will 114 // return zero oob bytes 115 t.Fatalf("ReadMsgUnix oobn = %d, want %d", oobn2, oobn) 116 } 117 oob2 = oob2[:oobn2] 118 if !bytes.Equal(oob, oob2) { 119 t.Fatal("ReadMsgUnix oob bytes don't match") 120 } 121 122 scm, err := syscall.ParseSocketControlMessage(oob2) 123 if err != nil { 124 t.Fatalf("ParseSocketControlMessage: %v", err) 125 } 126 newUcred, err := syscall.ParseUnixCredentials(&scm[0]) 127 if err != nil { 128 t.Fatalf("ParseUnixCredentials: %v", err) 129 } 130 if *newUcred != ucred { 131 t.Fatalf("ParseUnixCredentials = %+v, want %+v", newUcred, ucred) 132 } 133 } 134 } 135
