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net: pass MSG_CMSG_CLOEXEC flag in ReadMsgUnix

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As mentioned in #42765, calling "recvmsg" syscall on Linux should come
with "MSG_CMSG_CLOEXEC" flag.

For other systems which not supports "MSG_CMSG_CLOEXEC". ReadMsgUnix()
would check the header. If the header type is "syscall.SCM_RIGHTS",
then ReadMsgUnix() would parse the SocketControlMessage and call each
fd with "syscall.CloseOnExec"

Fixes #42765

Change-Id: I74347db72b465685d7684bf0f32415d285845ebb
GitHub-Last-Rev: ca59e2c9e0
GitHub-Pull-Request: golang/go#42768
Reviewed-on: https://go-review.googlesource.com/c/go/+/272226
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
This commit is contained in:
HowJMay 2021-04-19 18:06:54 +00:00 committed by Ian Lance Taylor
parent bbb510ccc9
commit e97d8eb027
12 changed files with 186 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/internal/poll/fd_unix.go
View File

@ -231,7 +231,7 @@ func (fd *FD) ReadFrom(p []byte) (int, syscall.Sockaddr, error) {
}
// ReadMsg wraps the recvmsg network call.
func (fd *FD) ReadMsg(p []byte, oob []byte) (int, int, int, syscall.Sockaddr, error) {
func (fd *FD) ReadMsg(p []byte, oob []byte, flags int) (int, int, int, syscall.Sockaddr, error) {
if err := fd.readLock(); err != nil {
return 0, 0, 0, nil, err
}
@ -240,7 +240,7 @@ func (fd *FD) ReadMsg(p []byte, oob []byte) (int, int, int, syscall.Sockaddr, er
return 0, 0, 0, nil, err
}
for {
n, oobn, flags, sa, err := syscall.Recvmsg(fd.Sysfd, p, oob, 0)
n, oobn, sysflags, sa, err := syscall.Recvmsg(fd.Sysfd, p, oob, flags)
if err != nil {
if err == syscall.EINTR {
continue
@ -253,7 +253,7 @@ func (fd *FD) ReadMsg(p []byte, oob []byte) (int, int, int, syscall.Sockaddr, er
}
}
err = fd.eofError(n, err)
return n, oobn, flags, sa, err
return n, oobn, sysflags, sa, err
}
}

3
src/internal/poll/fd_windows.go
View File

@ -1013,7 +1013,7 @@ func sockaddrToRaw(sa syscall.Sockaddr) (unsafe.Pointer, int32, error) {
}
// ReadMsg wraps the WSARecvMsg network call.
func (fd *FD) ReadMsg(p []byte, oob []byte) (int, int, int, syscall.Sockaddr, error) {
func (fd *FD) ReadMsg(p []byte, oob []byte, flags int) (int, int, int, syscall.Sockaddr, error) {
if err := fd.readLock(); err != nil {
return 0, 0, 0, nil, err
}
@ -1028,6 +1028,7 @@ func (fd *FD) ReadMsg(p []byte, oob []byte) (int, int, int, syscall.Sockaddr, er
o.rsa = new(syscall.RawSockaddrAny)
o.msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
o.msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
o.msg.Flags = uint32(flags)
n, err := execIO(o, func(o *operation) error {
return windows.WSARecvMsg(o.fd.Sysfd, &o.msg, &o.qty, &o.o, nil)
})

6
src/net/fd_posix.go
View File

@ -64,10 +64,10 @@ func (fd *netFD) readFrom(p []byte) (n int, sa syscall.Sockaddr, err error) {
return n, sa, wrapSyscallError(readFromSyscallName, err)
}
func (fd *netFD) readMsg(p []byte, oob []byte) (n, oobn, flags int, sa syscall.Sockaddr, err error) {
n, oobn, flags, sa, err = fd.pfd.ReadMsg(p, oob)
func (fd *netFD) readMsg(p []byte, oob []byte, flags int) (n, oobn, retflags int, sa syscall.Sockaddr, err error) {
n, oobn, retflags, sa, err = fd.pfd.ReadMsg(p, oob, flags)
runtime.KeepAlive(fd)
return n, oobn, flags, sa, wrapSyscallError(readMsgSyscallName, err)
return n, oobn, retflags, sa, wrapSyscallError(readMsgSyscallName, err)
}
func (fd *netFD) Write(p []byte) (nn int, err error) {

2
src/net/iprawsock_posix.go
View File

@ -75,7 +75,7 @@ func stripIPv4Header(n int, b []byte) int {
func (c *IPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
n, oobn, flags, sa, err = c.fd.readMsg(b, oob, 0)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &IPAddr{IP: sa.Addr[0:]}

2
src/net/net_fake.go
View File

@ -268,7 +268,7 @@ func (fd *netFD) readFrom(p []byte) (n int, sa syscall.Sockaddr, err error) {
return 0, nil, syscall.ENOSYS
}
func (fd *netFD) readMsg(p []byte, oob []byte) (n, oobn, flags int, sa syscall.Sockaddr, err error) {
func (fd *netFD) readMsg(p []byte, oob []byte, flags int) (n, oobn, retflags int, sa syscall.Sockaddr, err error) {
return 0, 0, 0, nil, syscall.ENOSYS
}

2
src/net/udpsock_posix.go
View File

@ -56,7 +56,7 @@ func (c *UDPConn) readFrom(b []byte, addr *UDPAddr) (int, *UDPAddr, error) {
func (c *UDPConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
n, oobn, flags, sa, err = c.fd.readMsg(b, oob, 0)
switch sa := sa.(type) {
case *syscall.SockaddrInet4:
addr = &UDPAddr{IP: sa.Addr[0:], Port: sa.Port}

6
src/net/unixsock_posix.go
View File

@ -113,7 +113,11 @@ func (c *UnixConn) readFrom(b []byte) (int, *UnixAddr, error) {
func (c *UnixConn) readMsg(b, oob []byte) (n, oobn, flags int, addr *UnixAddr, err error) {
var sa syscall.Sockaddr
n, oobn, flags, sa, err = c.fd.readMsg(b, oob)
n, oobn, flags, sa, err = c.fd.readMsg(b, oob, readMsgFlags)
if oobn > 0 {
setReadMsgCloseOnExec(oob[:oobn])
}
switch sa := sa.(type) {
case *syscall.SockaddrUnix:
if sa.Name != "" {

17
src/net/unixsock_readmsg_linux.go Normal file
View File

@ -0,0 +1,17 @@
// Copyright 2021 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.
//go:build linux
// +build linux
package net
import (
"syscall"
)
const readMsgFlags = syscall.MSG_CMSG_CLOEXEC
func setReadMsgCloseOnExec(oob []byte) {
}

13
src/net/unixsock_readmsg_other.go Normal file
View File

@ -0,0 +1,13 @@
// Copyright 2021 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.
//go:build (js && wasm) || windows
// +build js,wasm windows
package net
const readMsgFlags = 0
func setReadMsgCloseOnExec(oob []byte) {
}

33
src/net/unixsock_readmsg_posix.go Normal file
View File

@ -0,0 +1,33 @@
// Copyright 2021 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.
//go:build aix || darwin || dragonfly || freebsd || netbsd || openbsd || solaris
// +build aix darwin dragonfly freebsd netbsd openbsd solaris
package net
import (
"syscall"
)
const readMsgFlags = 0
func setReadMsgCloseOnExec(oob []byte) {
scms, err := syscall.ParseSocketControlMessage(oob)
if err != nil {
return
}
for _, scm := range scms {
if scm.Header.Level == syscall.SOL_SOCKET && scm.Header.Type == syscall.SCM_RIGHTS {
fds, err := syscall.ParseUnixRights(&scm)
if err != nil {
continue
}
for _, fd := range fds {
syscall.CloseOnExec(fd)
}
}
}
}

105
src/net/unixsock_readmsg_test.go Normal file
View File

@ -0,0 +1,105 @@
// Copyright 2021 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.
//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
package net
import (
"os"
"syscall"
"testing"
"time"
)
func TestUnixConnReadMsgUnixSCMRightsCloseOnExec(t *testing.T) {
if !testableNetwork("unix") {
t.Skip("not unix system")
}
scmFile, err := os.Open(os.DevNull)
if err != nil {
t.Fatalf("file open: %v", err)
}
defer scmFile.Close()
rights := syscall.UnixRights(int(scmFile.Fd()))
fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
if err != nil {
t.Fatalf("Socketpair: %v", err)
}
writeFile := os.NewFile(uintptr(fds[0]), "write-socket")
defer writeFile.Close()
readFile := os.NewFile(uintptr(fds[1]), "read-socket")
defer readFile.Close()
cw, err := FileConn(writeFile)
if err != nil {
t.Fatalf("FileConn: %v", err)
}
defer cw.Close()
cr, err := FileConn(readFile)
if err != nil {
t.Fatalf("FileConn: %v", err)
}
defer cr.Close()
ucw, ok := cw.(*UnixConn)
if !ok {
t.Fatalf("got %T; want UnixConn", cw)
}
ucr, ok := cr.(*UnixConn)
if !ok {
t.Fatalf("got %T; want UnixConn", cr)
}
oob := make([]byte, syscall.CmsgSpace(4))
err = ucw.SetWriteDeadline(time.Now().Add(5 * time.Second))
if err != nil {
t.Fatalf("Can't set unix connection timeout: %v", err)
}
_, _, err = ucw.WriteMsgUnix(nil, rights, nil)
if err != nil {
t.Fatalf("UnixConn readMsg: %v", err)
}
err = ucr.SetReadDeadline(time.Now().Add(5 * time.Second))
if err != nil {
t.Fatalf("Can't set unix connection timeout: %v", err)
}
_, oobn, _, _, err := ucr.ReadMsgUnix(nil, oob)
if err != nil {
t.Fatalf("UnixConn readMsg: %v", err)
}
scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
if err != nil {
t.Fatalf("ParseSocketControlMessage: %v", err)
}
if len(scms) != 1 {
t.Fatalf("got scms = %#v; expected 1 SocketControlMessage", scms)
}
scm := scms[0]
gotFds, err := syscall.ParseUnixRights(&scm)
if err != nil {
t.Fatalf("syscall.ParseUnixRights: %v", err)
}
if len(gotFds) != 1 {
t.Fatalf("got FDs %#v: wanted only 1 fd", gotFds)
}
defer func() {
if err := syscall.Close(int(gotFds[0])); err != nil {
t.Fatalf("fail to close gotFds: %v", err)
}
}()
flags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(gotFds[0]), uintptr(syscall.F_GETFD), 0)
if errno != 0 {
t.Fatalf("Can't get flags of fd:%#v, with err:%v", gotFds[0], errno)
}
if flags&syscall.FD_CLOEXEC == 0 {
t.Fatalf("got flags %#x, want %#x (FD_CLOEXEC) set", flags, syscall.FD_CLOEXEC)
}
}

4
src/syscall/creds_test.go
View File

@ -105,8 +105,8 @@ func TestSCMCredentials(t *testing.T) {
if err != nil {
t.Fatalf("ReadMsgUnix: %v", err)
}
if flags != 0 {
t.Fatalf("ReadMsgUnix flags = 0x%x, want 0", flags)
if flags != syscall.MSG_CMSG_CLOEXEC {
t.Fatalf("ReadMsgUnix flags = %#x, want %#x (MSG_CMSG_CLOEXEC)", flags, syscall.MSG_CMSG_CLOEXEC)
}
if n != tt.dataLen {
t.Fatalf("ReadMsgUnix n = %d, want %d", n, tt.dataLen)