conn, device, tun: set CLOEXEC on fds

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Brad Fitzpatrick 2022-07-01 21:28:52 -07:00 committed by Jason A. Donenfeld
parent 6a08d81f6b
commit c31a7b1ab4
6 changed files with 36 additions and 24 deletions

View File

@ -331,7 +331,7 @@ func create4(port uint16) (int, uint16, error) {
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {
@ -373,7 +373,7 @@ func create6(port uint16) (int, uint16, error) {
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET6, unix.AF_INET6,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {

View File

@ -204,7 +204,7 @@ func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netl
} }
func createNetlinkRouteSocket() (int, error) { func createNetlinkRouteSocket() (int, error) {
sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE) sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW|unix.SOCK_CLOEXEC, unix.NETLINK_ROUTE)
if err != nil { if err != nil {
return -1, err return -1, err
} }

View File

@ -107,7 +107,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
} }
} }
fd, err := unix.Socket(unix.AF_SYSTEM, unix.SOCK_DGRAM, 2) fd, err := socketCloexec(unix.AF_SYSTEM, unix.SOCK_DGRAM, 2)
if err != nil { if err != nil {
return nil, err return nil, err
} }
@ -173,7 +173,7 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
return nil, err return nil, err
} }
tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC) tun.routeSocket, err = socketCloexec(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
if err != nil { if err != nil {
tun.tunFile.Close() tun.tunFile.Close()
return nil, err return nil, err
@ -276,7 +276,7 @@ func (tun *NativeTun) Close() error {
} }
func (tun *NativeTun) setMTU(n int) error { func (tun *NativeTun) setMTU(n int) error {
fd, err := unix.Socket( fd, err := socketCloexec(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM,
0, 0,
@ -299,7 +299,7 @@ func (tun *NativeTun) setMTU(n int) error {
} }
func (tun *NativeTun) MTU() (int, error) { func (tun *NativeTun) MTU() (int, error) {
fd, err := unix.Socket( fd, err := socketCloexec(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM,
0, 0,
@ -317,3 +317,15 @@ func (tun *NativeTun) MTU() (int, error) {
return int(ifr.MTU), nil return int(ifr.MTU), nil
} }
func socketCloexec(family, sotype, proto int) (fd int, err error) {
// See go/src/net/sys_cloexec.go for background.
syscall.ForkLock.RLock()
defer syscall.ForkLock.RUnlock()
fd, err = unix.Socket(family, sotype, proto)
if err == nil {
unix.CloseOnExec(fd)
}
return
}

View File

@ -143,7 +143,7 @@ func tunName(fd uintptr) (string, error) {
// Destroy a named system interface // Destroy a named system interface
func tunDestroy(name string) error { func tunDestroy(name string) error {
fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0) fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
if err != nil { if err != nil {
return err return err
} }
@ -170,7 +170,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
return nil, fmt.Errorf("interface %s already exists", name) return nil, fmt.Errorf("interface %s already exists", name)
} }
tunFile, err := os.OpenFile("/dev/tun", unix.O_RDWR, 0) tunFile, err := os.OpenFile("/dev/tun", unix.O_RDWR|unix.O_CLOEXEC, 0)
if err != nil { if err != nil {
return nil, err return nil, err
} }
@ -213,7 +213,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
// Disable link-local v6, not just because WireGuard doesn't do that anyway, but // Disable link-local v6, not just because WireGuard doesn't do that anyway, but
// also because there are serious races with attaching and detaching LLv6 addresses // also because there are serious races with attaching and detaching LLv6 addresses
// in relation to interface lifetime within the FreeBSD kernel. // in relation to interface lifetime within the FreeBSD kernel.
confd6, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, 0) confd6, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
if err != nil { if err != nil {
tunFile.Close() tunFile.Close()
tunDestroy(assignedName) tunDestroy(assignedName)
@ -238,7 +238,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
} }
if name != "" { if name != "" {
confd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0) confd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
if err != nil { if err != nil {
tunFile.Close() tunFile.Close()
tunDestroy(assignedName) tunDestroy(assignedName)
@ -295,7 +295,7 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
return nil, err return nil, err
} }
tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC) tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW|unix.SOCK_CLOEXEC, unix.AF_UNSPEC)
if err != nil { if err != nil {
tun.tunFile.Close() tun.tunFile.Close()
return nil, err return nil, err
@ -397,7 +397,7 @@ func (tun *NativeTun) Close() error {
} }
func (tun *NativeTun) setMTU(n int) error { func (tun *NativeTun) setMTU(n int) error {
fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0) fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
if err != nil { if err != nil {
return err return err
} }
@ -414,7 +414,7 @@ func (tun *NativeTun) setMTU(n int) error {
} }
func (tun *NativeTun) MTU() (int, error) { func (tun *NativeTun) MTU() (int, error) {
fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0) fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
if err != nil { if err != nil {
return 0, err return 0, err
} }

View File

@ -99,7 +99,7 @@ func (tun *NativeTun) routineHackListener() {
} }
func createNetlinkSocket() (int, error) { func createNetlinkSocket() (int, error) {
sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE) sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW|unix.SOCK_CLOEXEC, unix.NETLINK_ROUTE)
if err != nil { if err != nil {
return -1, err return -1, err
} }
@ -194,7 +194,7 @@ func (tun *NativeTun) routineNetlinkListener() {
func getIFIndex(name string) (int32, error) { func getIFIndex(name string) (int32, error) {
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {
@ -228,7 +228,7 @@ func (tun *NativeTun) setMTU(n int) error {
// open datagram socket // open datagram socket
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {
@ -264,7 +264,7 @@ func (tun *NativeTun) MTU() (int, error) {
// open datagram socket // open datagram socket
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {
@ -400,7 +400,7 @@ func (tun *NativeTun) Close() error {
} }
func CreateTUN(name string, mtu int) (Device, error) { func CreateTUN(name string, mtu int) (Device, error) {
nfd, err := unix.Open(cloneDevicePath, os.O_RDWR, 0) nfd, err := unix.Open(cloneDevicePath, unix.O_RDWR|unix.O_CLOEXEC, 0)
if err != nil { if err != nil {
if os.IsNotExist(err) { if os.IsNotExist(err) {
return nil, fmt.Errorf("CreateTUN(%q) failed; %s does not exist", name, cloneDevicePath) return nil, fmt.Errorf("CreateTUN(%q) failed; %s does not exist", name, cloneDevicePath)

View File

@ -114,10 +114,10 @@ func CreateTUN(name string, mtu int) (Device, error) {
var err error var err error
if ifIndex != -1 { if ifIndex != -1 {
tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0) tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR|unix.O_CLOEXEC, 0)
} else { } else {
for ifIndex = 0; ifIndex < 256; ifIndex++ { for ifIndex = 0; ifIndex < 256; ifIndex++ {
tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0) tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR|unix.O_CLOEXEC, 0)
if err == nil || !errors.Is(err, syscall.EBUSY) { if err == nil || !errors.Is(err, syscall.EBUSY) {
break break
} }
@ -165,7 +165,7 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
return nil, err return nil, err
} }
tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC) tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW|unix.SOCK_CLOEXEC, unix.AF_UNSPEC)
if err != nil { if err != nil {
tun.tunFile.Close() tun.tunFile.Close()
return nil, err return nil, err
@ -270,7 +270,7 @@ func (tun *NativeTun) setMTU(n int) error {
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {
@ -304,7 +304,7 @@ func (tun *NativeTun) MTU() (int, error) {
fd, err := unix.Socket( fd, err := unix.Socket(
unix.AF_INET, unix.AF_INET,
unix.SOCK_DGRAM, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC,
0, 0,
) )
if err != nil { if err != nil {