syscall: Test SCM credentials on Linux.

This test was previously removed in 087c6e15702e.

R=bradfitz, rsc, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/6506061

diff --git a/src/pkg/syscall/creds_test.go b/src/pkg/syscall/creds_test.go
new file mode 100644 (file)
index 0000000..6eaa97e
--- /dev/null
+++ b/src/pkg/syscall/creds_test.go
@@ -0,0 +1,109 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package syscall_test
+
+import (
+       "bytes"
+       "net"
+       "os"
+       "syscall"
+       "testing"
+)
+
+// TestSCMCredentials tests the sending and receiving of credentials
+// (PID, UID, GID) in an ancillary message between two UNIX
+// sockets. The SO_PASSCRED socket option is enabled on the sending
+// socket for this to work.
+func TestSCMCredentials(t *testing.T) {
+       fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
+       if err != nil {
+               t.Fatalf("Socketpair: %v", err)
+       }
+       defer syscall.Close(fds[0])
+       defer syscall.Close(fds[1])
+
+       err = syscall.SetsockoptInt(fds[0], syscall.SOL_SOCKET, syscall.SO_PASSCRED, 1)
+       if err != nil {
+               t.Fatalf("SetsockoptInt: %v", err)
+       }
+
+       srv, err := net.FileConn(os.NewFile(uintptr(fds[0]), ""))
+       if err != nil {
+               t.Errorf("FileConn: %v", err)
+               return
+       }
+       defer srv.Close()
+
+       cli, err := net.FileConn(os.NewFile(uintptr(fds[1]), ""))
+       if err != nil {
+               t.Errorf("FileConn: %v", err)
+               return
+       }
+       defer cli.Close()
+
+       var ucred syscall.Ucred
+       if os.Getuid() != 0 {
+               ucred.Pid = int32(os.Getpid())
+               ucred.Uid = 0
+               ucred.Gid = 0
+               oob := syscall.UnixCredentials(&ucred)
+               _, _, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
+               if err.(*net.OpError).Err != syscall.EPERM {
+                       t.Fatalf("WriteMsgUnix failed with %v, want EPERM", err)
+               }
+       }
+
+       ucred.Pid = int32(os.Getpid())
+       ucred.Uid = uint32(os.Getuid())
+       ucred.Gid = uint32(os.Getgid())
+       oob := syscall.UnixCredentials(&ucred)
+
+       // this is going to send a dummy byte
+       n, oobn, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
+       if err != nil {
+               t.Fatalf("WriteMsgUnix: %v", err)
+       }
+       if n != 0 {
+               t.Fatalf("WriteMsgUnix n = %d, want 0", n)
+       }
+       if oobn != len(oob) {
+               t.Fatalf("WriteMsgUnix oobn = %d, want %d", oobn, len(oob))
+       }
+
+       oob2 := make([]byte, 10*len(oob))
+       n, oobn2, flags, _, err := srv.(*net.UnixConn).ReadMsgUnix(nil, oob2)
+       if err != nil {
+               t.Fatalf("ReadMsgUnix: %v", err)
+       }
+       if flags != 0 {
+               t.Fatalf("ReadMsgUnix flags = 0x%x, want 0", flags)
+       }
+       if n != 1 {
+               t.Fatalf("ReadMsgUnix n = %d, want 1 (dummy byte)", n)
+       }
+       if oobn2 != oobn {
+               // without SO_PASSCRED set on the socket, ReadMsgUnix will
+               // return zero oob bytes
+               t.Fatalf("ReadMsgUnix oobn = %d, want %d", oobn2, oobn)
+       }
+       oob2 = oob2[:oobn2]
+       if !bytes.Equal(oob, oob2) {
+               t.Fatal("ReadMsgUnix oob bytes don't match")
+       }
+
+       scm, err := syscall.ParseSocketControlMessage(oob2)
+       if err != nil {
+               t.Fatalf("ParseSocketControlMessage: %v", err)
+       }
+       newUcred, err := syscall.ParseUnixCredentials(&scm[0])
+       if err != nil {
+               t.Fatalf("ParseUnixCredentials: %v", err)
+       }
+       if *newUcred != ucred {
+               t.Fatalf("ParseUnixCredentials = %+v, want %+v", newUcred, ucred)
+       }
+}