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go/src/syscall/lsf_linux.go
Lorenz Bauer 9c8c27a318 syscall: use SOCK_CLOEXEC when creating sockets
LsfSocket, SetLsfPromisc and NetlinkRIB currently don't force the CLOEXEC
flag on the sockets they create. While the former two functions are
deprecated, NetlinkRIB is called by various functions related to
net.Interface.

Add a helper to create CLOEXEC sockets, and use it from SetLsfPromisc and
NetlinkRIB. LsfSocket is unchanged since we don't want to break callers.

Fixes #36053

Change-Id: I72fe2b167996797698d8a44b0d28165045c42d3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/210517
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-12-11 00:01:17 +00:00

87 lines
2.1 KiB
Go

// Copyright 2011 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.
// Linux socket filter
package syscall
import (
"unsafe"
)
// Deprecated: Use golang.org/x/net/bpf instead.
func LsfStmt(code, k int) *SockFilter {
return &SockFilter{Code: uint16(code), K: uint32(k)}
}
// Deprecated: Use golang.org/x/net/bpf instead.
func LsfJump(code, k, jt, jf int) *SockFilter {
return &SockFilter{Code: uint16(code), Jt: uint8(jt), Jf: uint8(jf), K: uint32(k)}
}
// Deprecated: Use golang.org/x/net/bpf instead.
func LsfSocket(ifindex, proto int) (int, error) {
var lsall SockaddrLinklayer
// This is missing SOCK_CLOEXEC, but adding the flag
// could break callers.
s, e := Socket(AF_PACKET, SOCK_RAW, proto)
if e != nil {
return 0, e
}
p := (*[2]byte)(unsafe.Pointer(&lsall.Protocol))
p[0] = byte(proto >> 8)
p[1] = byte(proto)
lsall.Ifindex = ifindex
e = Bind(s, &lsall)
if e != nil {
Close(s)
return 0, e
}
return s, nil
}
type iflags struct {
name [IFNAMSIZ]byte
flags uint16
}
// Deprecated: Use golang.org/x/net/bpf instead.
func SetLsfPromisc(name string, m bool) error {
s, e := cloexecSocket(AF_INET, SOCK_DGRAM, 0)
if e != nil {
return e
}
defer Close(s)
var ifl iflags
copy(ifl.name[:], []byte(name))
_, _, ep := Syscall(SYS_IOCTL, uintptr(s), SIOCGIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
if ep != 0 {
return Errno(ep)
}
if m {
ifl.flags |= uint16(IFF_PROMISC)
} else {
ifl.flags &^= uint16(IFF_PROMISC)
}
_, _, ep = Syscall(SYS_IOCTL, uintptr(s), SIOCSIFFLAGS, uintptr(unsafe.Pointer(&ifl)))
if ep != 0 {
return Errno(ep)
}
return nil
}
// Deprecated: Use golang.org/x/net/bpf instead.
func AttachLsf(fd int, i []SockFilter) error {
var p SockFprog
p.Len = uint16(len(i))
p.Filter = (*SockFilter)(unsafe.Pointer(&i[0]))
return setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, unsafe.Pointer(&p), unsafe.Sizeof(p))
}
// Deprecated: Use golang.org/x/net/bpf instead.
func DetachLsf(fd int) error {
var dummy int
return setsockopt(fd, SOL_SOCKET, SO_DETACH_FILTER, unsafe.Pointer(&dummy), unsafe.Sizeof(dummy))
}