643 lines
12 KiB
Go
643 lines
12 KiB
Go
// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
|
|
// All rights reserved.
|
|
//
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
package capability
|
|
|
|
import (
|
|
"bufio"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
"os"
|
|
"strings"
|
|
"syscall"
|
|
)
|
|
|
|
var errUnknownVers = errors.New("unknown capability version")
|
|
|
|
const (
|
|
linuxCapVer1 = 0x19980330
|
|
linuxCapVer2 = 0x20071026
|
|
linuxCapVer3 = 0x20080522
|
|
)
|
|
|
|
var (
|
|
capVers uint32
|
|
capLastCap Cap
|
|
)
|
|
|
|
func init() {
|
|
var hdr capHeader
|
|
capget(&hdr, nil)
|
|
capVers = hdr.version
|
|
|
|
if initLastCap() == nil {
|
|
CAP_LAST_CAP = capLastCap
|
|
if capLastCap > 31 {
|
|
capUpperMask = (uint32(1) << (uint(capLastCap) - 31)) - 1
|
|
} else {
|
|
capUpperMask = 0
|
|
}
|
|
}
|
|
}
|
|
|
|
func initLastCap() error {
|
|
if capLastCap != 0 {
|
|
return nil
|
|
}
|
|
|
|
f, err := os.Open("/proc/sys/kernel/cap_last_cap")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer f.Close()
|
|
|
|
var b []byte = make([]byte, 11)
|
|
_, err = f.Read(b)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
fmt.Sscanf(string(b), "%d", &capLastCap)
|
|
|
|
return nil
|
|
}
|
|
|
|
func mkStringCap(c Capabilities, which CapType) (ret string) {
|
|
for i, first := Cap(0), true; i <= CAP_LAST_CAP; i++ {
|
|
if !c.Get(which, i) {
|
|
continue
|
|
}
|
|
if first {
|
|
first = false
|
|
} else {
|
|
ret += ", "
|
|
}
|
|
ret += i.String()
|
|
}
|
|
return
|
|
}
|
|
|
|
func mkString(c Capabilities, max CapType) (ret string) {
|
|
ret = "{"
|
|
for i := CapType(1); i <= max; i <<= 1 {
|
|
ret += " " + i.String() + "=\""
|
|
if c.Empty(i) {
|
|
ret += "empty"
|
|
} else if c.Full(i) {
|
|
ret += "full"
|
|
} else {
|
|
ret += c.StringCap(i)
|
|
}
|
|
ret += "\""
|
|
}
|
|
ret += " }"
|
|
return
|
|
}
|
|
|
|
func newPid(pid int) (c Capabilities, err error) {
|
|
switch capVers {
|
|
case linuxCapVer1:
|
|
p := new(capsV1)
|
|
p.hdr.version = capVers
|
|
p.hdr.pid = int32(pid)
|
|
c = p
|
|
case linuxCapVer2, linuxCapVer3:
|
|
p := new(capsV3)
|
|
p.hdr.version = capVers
|
|
p.hdr.pid = int32(pid)
|
|
c = p
|
|
default:
|
|
err = errUnknownVers
|
|
return
|
|
}
|
|
return
|
|
}
|
|
|
|
type capsV1 struct {
|
|
hdr capHeader
|
|
data capData
|
|
}
|
|
|
|
func (c *capsV1) Get(which CapType, what Cap) bool {
|
|
if what > 32 {
|
|
return false
|
|
}
|
|
|
|
switch which {
|
|
case EFFECTIVE:
|
|
return (1<<uint(what))&c.data.effective != 0
|
|
case PERMITTED:
|
|
return (1<<uint(what))&c.data.permitted != 0
|
|
case INHERITABLE:
|
|
return (1<<uint(what))&c.data.inheritable != 0
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
func (c *capsV1) getData(which CapType) (ret uint32) {
|
|
switch which {
|
|
case EFFECTIVE:
|
|
ret = c.data.effective
|
|
case PERMITTED:
|
|
ret = c.data.permitted
|
|
case INHERITABLE:
|
|
ret = c.data.inheritable
|
|
}
|
|
return
|
|
}
|
|
|
|
func (c *capsV1) Empty(which CapType) bool {
|
|
return c.getData(which) == 0
|
|
}
|
|
|
|
func (c *capsV1) Full(which CapType) bool {
|
|
return (c.getData(which) & 0x7fffffff) == 0x7fffffff
|
|
}
|
|
|
|
func (c *capsV1) Set(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
if what > 32 {
|
|
continue
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data.effective |= 1 << uint(what)
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data.permitted |= 1 << uint(what)
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data.inheritable |= 1 << uint(what)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsV1) Unset(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
if what > 32 {
|
|
continue
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data.effective &= ^(1 << uint(what))
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data.permitted &= ^(1 << uint(what))
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data.inheritable &= ^(1 << uint(what))
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsV1) Fill(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data.effective = 0x7fffffff
|
|
c.data.permitted = 0x7fffffff
|
|
c.data.inheritable = 0
|
|
}
|
|
}
|
|
|
|
func (c *capsV1) Clear(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data.effective = 0
|
|
c.data.permitted = 0
|
|
c.data.inheritable = 0
|
|
}
|
|
}
|
|
|
|
func (c *capsV1) StringCap(which CapType) (ret string) {
|
|
return mkStringCap(c, which)
|
|
}
|
|
|
|
func (c *capsV1) String() (ret string) {
|
|
return mkString(c, BOUNDING)
|
|
}
|
|
|
|
func (c *capsV1) Load() (err error) {
|
|
return capget(&c.hdr, &c.data)
|
|
}
|
|
|
|
func (c *capsV1) Apply(kind CapType) error {
|
|
if kind&CAPS == CAPS {
|
|
return capset(&c.hdr, &c.data)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type capsV3 struct {
|
|
hdr capHeader
|
|
data [2]capData
|
|
bounds [2]uint32
|
|
ambient [2]uint32
|
|
}
|
|
|
|
func (c *capsV3) Get(which CapType, what Cap) bool {
|
|
var i uint
|
|
if what > 31 {
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
switch which {
|
|
case EFFECTIVE:
|
|
return (1<<uint(what))&c.data[i].effective != 0
|
|
case PERMITTED:
|
|
return (1<<uint(what))&c.data[i].permitted != 0
|
|
case INHERITABLE:
|
|
return (1<<uint(what))&c.data[i].inheritable != 0
|
|
case BOUNDING:
|
|
return (1<<uint(what))&c.bounds[i] != 0
|
|
case AMBIENT:
|
|
return (1<<uint(what))&c.ambient[i] != 0
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
func (c *capsV3) getData(which CapType, dest []uint32) {
|
|
switch which {
|
|
case EFFECTIVE:
|
|
dest[0] = c.data[0].effective
|
|
dest[1] = c.data[1].effective
|
|
case PERMITTED:
|
|
dest[0] = c.data[0].permitted
|
|
dest[1] = c.data[1].permitted
|
|
case INHERITABLE:
|
|
dest[0] = c.data[0].inheritable
|
|
dest[1] = c.data[1].inheritable
|
|
case BOUNDING:
|
|
dest[0] = c.bounds[0]
|
|
dest[1] = c.bounds[1]
|
|
case AMBIENT:
|
|
dest[0] = c.ambient[0]
|
|
dest[1] = c.ambient[1]
|
|
}
|
|
}
|
|
|
|
func (c *capsV3) Empty(which CapType) bool {
|
|
var data [2]uint32
|
|
c.getData(which, data[:])
|
|
return data[0] == 0 && data[1] == 0
|
|
}
|
|
|
|
func (c *capsV3) Full(which CapType) bool {
|
|
var data [2]uint32
|
|
c.getData(which, data[:])
|
|
if (data[0] & 0xffffffff) != 0xffffffff {
|
|
return false
|
|
}
|
|
return (data[1] & capUpperMask) == capUpperMask
|
|
}
|
|
|
|
func (c *capsV3) Set(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
var i uint
|
|
if what > 31 {
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data[i].effective |= 1 << uint(what)
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data[i].permitted |= 1 << uint(what)
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data[i].inheritable |= 1 << uint(what)
|
|
}
|
|
if which&BOUNDING != 0 {
|
|
c.bounds[i] |= 1 << uint(what)
|
|
}
|
|
if which&AMBIENT != 0 {
|
|
c.ambient[i] |= 1 << uint(what)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsV3) Unset(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
var i uint
|
|
if what > 31 {
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data[i].effective &= ^(1 << uint(what))
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data[i].permitted &= ^(1 << uint(what))
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data[i].inheritable &= ^(1 << uint(what))
|
|
}
|
|
if which&BOUNDING != 0 {
|
|
c.bounds[i] &= ^(1 << uint(what))
|
|
}
|
|
if which&AMBIENT != 0 {
|
|
c.ambient[i] &= ^(1 << uint(what))
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsV3) Fill(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data[0].effective = 0xffffffff
|
|
c.data[0].permitted = 0xffffffff
|
|
c.data[0].inheritable = 0
|
|
c.data[1].effective = 0xffffffff
|
|
c.data[1].permitted = 0xffffffff
|
|
c.data[1].inheritable = 0
|
|
}
|
|
|
|
if kind&BOUNDS == BOUNDS {
|
|
c.bounds[0] = 0xffffffff
|
|
c.bounds[1] = 0xffffffff
|
|
}
|
|
if kind&AMBS == AMBS {
|
|
c.ambient[0] = 0xffffffff
|
|
c.ambient[1] = 0xffffffff
|
|
}
|
|
}
|
|
|
|
func (c *capsV3) Clear(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data[0].effective = 0
|
|
c.data[0].permitted = 0
|
|
c.data[0].inheritable = 0
|
|
c.data[1].effective = 0
|
|
c.data[1].permitted = 0
|
|
c.data[1].inheritable = 0
|
|
}
|
|
|
|
if kind&BOUNDS == BOUNDS {
|
|
c.bounds[0] = 0
|
|
c.bounds[1] = 0
|
|
}
|
|
if kind&AMBS == AMBS {
|
|
c.ambient[0] = 0
|
|
c.ambient[1] = 0
|
|
}
|
|
}
|
|
|
|
func (c *capsV3) StringCap(which CapType) (ret string) {
|
|
return mkStringCap(c, which)
|
|
}
|
|
|
|
func (c *capsV3) String() (ret string) {
|
|
return mkString(c, BOUNDING)
|
|
}
|
|
|
|
func (c *capsV3) Load() (err error) {
|
|
err = capget(&c.hdr, &c.data[0])
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
var status_path string
|
|
|
|
if c.hdr.pid == 0 {
|
|
status_path = fmt.Sprintf("/proc/self/status")
|
|
} else {
|
|
status_path = fmt.Sprintf("/proc/%d/status", c.hdr.pid)
|
|
}
|
|
|
|
f, err := os.Open(status_path)
|
|
if err != nil {
|
|
return
|
|
}
|
|
b := bufio.NewReader(f)
|
|
for {
|
|
line, e := b.ReadString('\n')
|
|
if e != nil {
|
|
if e != io.EOF {
|
|
err = e
|
|
}
|
|
break
|
|
}
|
|
if strings.HasPrefix(line, "CapB") {
|
|
fmt.Sscanf(line[4:], "nd: %08x%08x", &c.bounds[1], &c.bounds[0])
|
|
continue
|
|
}
|
|
if strings.HasPrefix(line, "CapA") {
|
|
fmt.Sscanf(line[4:], "mb: %08x%08x", &c.ambient[1], &c.ambient[0])
|
|
continue
|
|
}
|
|
}
|
|
f.Close()
|
|
|
|
return
|
|
}
|
|
|
|
func (c *capsV3) Apply(kind CapType) (err error) {
|
|
if kind&BOUNDS == BOUNDS {
|
|
var data [2]capData
|
|
err = capget(&c.hdr, &data[0])
|
|
if err != nil {
|
|
return
|
|
}
|
|
if (1<<uint(CAP_SETPCAP))&data[0].effective != 0 {
|
|
for i := Cap(0); i <= CAP_LAST_CAP; i++ {
|
|
if c.Get(BOUNDING, i) {
|
|
continue
|
|
}
|
|
err = prctl(syscall.PR_CAPBSET_DROP, uintptr(i), 0, 0, 0)
|
|
if err != nil {
|
|
// Ignore EINVAL since the capability may not be supported in this system.
|
|
if errno, ok := err.(syscall.Errno); ok && errno == syscall.EINVAL {
|
|
err = nil
|
|
continue
|
|
}
|
|
return
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if kind&CAPS == CAPS {
|
|
err = capset(&c.hdr, &c.data[0])
|
|
if err != nil {
|
|
return
|
|
}
|
|
}
|
|
|
|
if kind&AMBS == AMBS {
|
|
for i := Cap(0); i <= CAP_LAST_CAP; i++ {
|
|
action := pr_CAP_AMBIENT_LOWER
|
|
if c.Get(AMBIENT, i) {
|
|
action = pr_CAP_AMBIENT_RAISE
|
|
}
|
|
err := prctl(pr_CAP_AMBIENT, action, uintptr(i), 0, 0)
|
|
// Ignore EINVAL as not supported on kernels before 4.3
|
|
if errno, ok := err.(syscall.Errno); ok && errno == syscall.EINVAL {
|
|
err = nil
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
func newFile(path string) (c Capabilities, err error) {
|
|
c = &capsFile{path: path}
|
|
return
|
|
}
|
|
|
|
type capsFile struct {
|
|
path string
|
|
data vfscapData
|
|
}
|
|
|
|
func (c *capsFile) Get(which CapType, what Cap) bool {
|
|
var i uint
|
|
if what > 31 {
|
|
if c.data.version == 1 {
|
|
return false
|
|
}
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
switch which {
|
|
case EFFECTIVE:
|
|
return (1<<uint(what))&c.data.effective[i] != 0
|
|
case PERMITTED:
|
|
return (1<<uint(what))&c.data.data[i].permitted != 0
|
|
case INHERITABLE:
|
|
return (1<<uint(what))&c.data.data[i].inheritable != 0
|
|
}
|
|
|
|
return false
|
|
}
|
|
|
|
func (c *capsFile) getData(which CapType, dest []uint32) {
|
|
switch which {
|
|
case EFFECTIVE:
|
|
dest[0] = c.data.effective[0]
|
|
dest[1] = c.data.effective[1]
|
|
case PERMITTED:
|
|
dest[0] = c.data.data[0].permitted
|
|
dest[1] = c.data.data[1].permitted
|
|
case INHERITABLE:
|
|
dest[0] = c.data.data[0].inheritable
|
|
dest[1] = c.data.data[1].inheritable
|
|
}
|
|
}
|
|
|
|
func (c *capsFile) Empty(which CapType) bool {
|
|
var data [2]uint32
|
|
c.getData(which, data[:])
|
|
return data[0] == 0 && data[1] == 0
|
|
}
|
|
|
|
func (c *capsFile) Full(which CapType) bool {
|
|
var data [2]uint32
|
|
c.getData(which, data[:])
|
|
if c.data.version == 0 {
|
|
return (data[0] & 0x7fffffff) == 0x7fffffff
|
|
}
|
|
if (data[0] & 0xffffffff) != 0xffffffff {
|
|
return false
|
|
}
|
|
return (data[1] & capUpperMask) == capUpperMask
|
|
}
|
|
|
|
func (c *capsFile) Set(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
var i uint
|
|
if what > 31 {
|
|
if c.data.version == 1 {
|
|
continue
|
|
}
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data.effective[i] |= 1 << uint(what)
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data.data[i].permitted |= 1 << uint(what)
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data.data[i].inheritable |= 1 << uint(what)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsFile) Unset(which CapType, caps ...Cap) {
|
|
for _, what := range caps {
|
|
var i uint
|
|
if what > 31 {
|
|
if c.data.version == 1 {
|
|
continue
|
|
}
|
|
i = uint(what) >> 5
|
|
what %= 32
|
|
}
|
|
|
|
if which&EFFECTIVE != 0 {
|
|
c.data.effective[i] &= ^(1 << uint(what))
|
|
}
|
|
if which&PERMITTED != 0 {
|
|
c.data.data[i].permitted &= ^(1 << uint(what))
|
|
}
|
|
if which&INHERITABLE != 0 {
|
|
c.data.data[i].inheritable &= ^(1 << uint(what))
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsFile) Fill(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data.effective[0] = 0xffffffff
|
|
c.data.data[0].permitted = 0xffffffff
|
|
c.data.data[0].inheritable = 0
|
|
if c.data.version == 2 {
|
|
c.data.effective[1] = 0xffffffff
|
|
c.data.data[1].permitted = 0xffffffff
|
|
c.data.data[1].inheritable = 0
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsFile) Clear(kind CapType) {
|
|
if kind&CAPS == CAPS {
|
|
c.data.effective[0] = 0
|
|
c.data.data[0].permitted = 0
|
|
c.data.data[0].inheritable = 0
|
|
if c.data.version == 2 {
|
|
c.data.effective[1] = 0
|
|
c.data.data[1].permitted = 0
|
|
c.data.data[1].inheritable = 0
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *capsFile) StringCap(which CapType) (ret string) {
|
|
return mkStringCap(c, which)
|
|
}
|
|
|
|
func (c *capsFile) String() (ret string) {
|
|
return mkString(c, INHERITABLE)
|
|
}
|
|
|
|
func (c *capsFile) Load() (err error) {
|
|
return getVfsCap(c.path, &c.data)
|
|
}
|
|
|
|
func (c *capsFile) Apply(kind CapType) (err error) {
|
|
if kind&CAPS == CAPS {
|
|
return setVfsCap(c.path, &c.data)
|
|
}
|
|
return
|
|
}
|