Update cri to 9f39e32895.
Signed-off-by: Lantao Liu <lantaol@google.com>
This commit is contained in:
Lantao Liu
593
vendor/github.com/opencontainers/selinux/go-selinux/selinux.go
generated
vendored
593
vendor/github.com/opencontainers/selinux/go-selinux/selinux.go
generated
vendored
@@ -1,593 +0,0 @@
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// +build linux
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package selinux
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import (
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"bufio"
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"crypto/rand"
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"encoding/binary"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"regexp"
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"strconv"
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"strings"
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"sync"
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"syscall"
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)
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const (
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// Enforcing constant indicate SELinux is in enforcing mode
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Enforcing = 1
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// Permissive constant to indicate SELinux is in permissive mode
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Permissive = 0
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// Disabled constant to indicate SELinux is disabled
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Disabled = -1
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selinuxDir = "/etc/selinux/"
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selinuxConfig = selinuxDir + "config"
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selinuxTypeTag = "SELINUXTYPE"
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selinuxTag = "SELINUX"
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selinuxPath = "/sys/fs/selinux"
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xattrNameSelinux = "security.selinux"
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stRdOnly = 0x01
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)
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type selinuxState struct {
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enabledSet bool
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enabled bool
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selinuxfsSet bool
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selinuxfs string
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mcsList map[string]bool
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sync.Mutex
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}
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var (
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assignRegex = regexp.MustCompile(`^([^=]+)=(.*)$`)
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state = selinuxState{
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mcsList: make(map[string]bool),
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}
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)
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// Context is a representation of the SELinux label broken into 4 parts
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type Context map[string]string
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func (s *selinuxState) setEnable(enabled bool) bool {
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s.Lock()
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defer s.Unlock()
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s.enabledSet = true
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s.enabled = enabled
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return s.enabled
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}
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func (s *selinuxState) getEnabled() bool {
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s.Lock()
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enabled := s.enabled
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enabledSet := s.enabledSet
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s.Unlock()
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if enabledSet {
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return enabled
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}
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enabled = false
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if fs := getSelinuxMountPoint(); fs != "" {
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if con, _ := CurrentLabel(); con != "kernel" {
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enabled = true
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}
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}
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return s.setEnable(enabled)
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}
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// SetDisabled disables selinux support for the package
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func SetDisabled() {
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state.setEnable(false)
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}
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func (s *selinuxState) setSELinuxfs(selinuxfs string) string {
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s.Lock()
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defer s.Unlock()
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s.selinuxfsSet = true
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s.selinuxfs = selinuxfs
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return s.selinuxfs
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}
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func (s *selinuxState) getSELinuxfs() string {
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s.Lock()
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selinuxfs := s.selinuxfs
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selinuxfsSet := s.selinuxfsSet
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s.Unlock()
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if selinuxfsSet {
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return selinuxfs
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}
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selinuxfs = ""
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return selinuxfs
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}
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defer f.Close()
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scanner := bufio.NewScanner(f)
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for scanner.Scan() {
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txt := scanner.Text()
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// Safe as mountinfo encodes mountpoints with spaces as \040.
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sepIdx := strings.Index(txt, " - ")
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if sepIdx == -1 {
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continue
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}
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if !strings.Contains(txt[sepIdx:], "selinuxfs") {
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continue
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}
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fields := strings.Split(txt, " ")
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if len(fields) < 5 {
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continue
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}
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selinuxfs = fields[4]
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break
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}
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if selinuxfs != "" {
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var buf syscall.Statfs_t
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syscall.Statfs(selinuxfs, &buf)
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if (buf.Flags & stRdOnly) == 1 {
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selinuxfs = ""
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}
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}
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return s.setSELinuxfs(selinuxfs)
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}
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// getSelinuxMountPoint returns the path to the mountpoint of an selinuxfs
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// filesystem or an empty string if no mountpoint is found. Selinuxfs is
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// a proc-like pseudo-filesystem that exposes the selinux policy API to
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// processes. The existence of an selinuxfs mount is used to determine
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// whether selinux is currently enabled or not.
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func getSelinuxMountPoint() string {
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return state.getSELinuxfs()
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}
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// GetEnabled returns whether selinux is currently enabled.
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func GetEnabled() bool {
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return state.getEnabled()
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}
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func readConfig(target string) (value string) {
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var (
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val, key string
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bufin *bufio.Reader
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)
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in, err := os.Open(selinuxConfig)
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if err != nil {
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return ""
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}
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defer in.Close()
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bufin = bufio.NewReader(in)
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for done := false; !done; {
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var line string
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if line, err = bufin.ReadString('\n'); err != nil {
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if err != io.EOF {
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return ""
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}
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done = true
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}
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line = strings.TrimSpace(line)
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if len(line) == 0 {
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// Skip blank lines
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continue
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}
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if line[0] == ';' || line[0] == '#' {
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// Skip comments
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continue
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}
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if groups := assignRegex.FindStringSubmatch(line); groups != nil {
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key, val = strings.TrimSpace(groups[1]), strings.TrimSpace(groups[2])
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if key == target {
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return strings.Trim(val, "\"")
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}
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}
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}
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return ""
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}
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func getSELinuxPolicyRoot() string {
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return selinuxDir + readConfig(selinuxTypeTag)
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}
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func readCon(name string) (string, error) {
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var val string
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in, err := os.Open(name)
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if err != nil {
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return "", err
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}
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defer in.Close()
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_, err = fmt.Fscanf(in, "%s", &val)
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return val, err
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}
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// SetFileLabel sets the SELinux label for this path or returns an error.
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func SetFileLabel(path string, label string) error {
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return lsetxattr(path, xattrNameSelinux, []byte(label), 0)
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}
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// FileLabel returns the SELinux label for this path or returns an error.
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func FileLabel(path string) (string, error) {
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label, err := lgetxattr(path, xattrNameSelinux)
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if err != nil {
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return "", err
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}
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// Trim the NUL byte at the end of the byte buffer, if present.
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if len(label) > 0 && label[len(label)-1] == '\x00' {
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label = label[:len(label)-1]
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}
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return string(label), nil
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}
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/*
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SetFSCreateLabel tells kernel the label to create all file system objects
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created by this task. Setting label="" to return to default.
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*/
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func SetFSCreateLabel(label string) error {
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return writeCon(fmt.Sprintf("/proc/self/task/%d/attr/fscreate", syscall.Gettid()), label)
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}
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/*
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FSCreateLabel returns the default label the kernel which the kernel is using
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for file system objects created by this task. "" indicates default.
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*/
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func FSCreateLabel() (string, error) {
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return readCon(fmt.Sprintf("/proc/self/task/%d/attr/fscreate", syscall.Gettid()))
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}
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// CurrentLabel returns the SELinux label of the current process thread, or an error.
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func CurrentLabel() (string, error) {
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return readCon(fmt.Sprintf("/proc/self/task/%d/attr/current", syscall.Gettid()))
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}
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// PidLabel returns the SELinux label of the given pid, or an error.
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func PidLabel(pid int) (string, error) {
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return readCon(fmt.Sprintf("/proc/%d/attr/current", pid))
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}
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/*
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ExecLabel returns the SELinux label that the kernel will use for any programs
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that are executed by the current process thread, or an error.
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*/
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func ExecLabel() (string, error) {
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return readCon(fmt.Sprintf("/proc/self/task/%d/attr/exec", syscall.Gettid()))
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}
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func writeCon(name string, val string) error {
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out, err := os.OpenFile(name, os.O_WRONLY, 0)
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if err != nil {
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return err
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}
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defer out.Close()
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if val != "" {
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_, err = out.Write([]byte(val))
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} else {
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_, err = out.Write(nil)
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}
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return err
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}
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/*
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SetExecLabel sets the SELinux label that the kernel will use for any programs
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that are executed by the current process thread, or an error.
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*/
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func SetExecLabel(label string) error {
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return writeCon(fmt.Sprintf("/proc/self/task/%d/attr/exec", syscall.Gettid()), label)
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}
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// Get returns the Context as a string
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func (c Context) Get() string {
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return fmt.Sprintf("%s:%s:%s:%s", c["user"], c["role"], c["type"], c["level"])
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}
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// NewContext creates a new Context struct from the specified label
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func NewContext(label string) Context {
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c := make(Context)
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if len(label) != 0 {
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con := strings.SplitN(label, ":", 4)
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c["user"] = con[0]
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c["role"] = con[1]
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c["type"] = con[2]
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c["level"] = con[3]
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}
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return c
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}
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// ReserveLabel reserves the MLS/MCS level component of the specified label
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func ReserveLabel(label string) {
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if len(label) != 0 {
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con := strings.SplitN(label, ":", 4)
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mcsAdd(con[3])
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}
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}
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func selinuxEnforcePath() string {
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return fmt.Sprintf("%s/enforce", selinuxPath)
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}
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// EnforceMode returns the current SELinux mode Enforcing, Permissive, Disabled
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func EnforceMode() int {
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var enforce int
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enforceS, err := readCon(selinuxEnforcePath())
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if err != nil {
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return -1
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}
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enforce, err = strconv.Atoi(string(enforceS))
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if err != nil {
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return -1
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}
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return enforce
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}
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/*
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SetEnforceMode sets the current SELinux mode Enforcing, Permissive.
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Disabled is not valid, since this needs to be set at boot time.
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*/
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func SetEnforceMode(mode int) error {
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||||
return writeCon(selinuxEnforcePath(), fmt.Sprintf("%d", mode))
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}
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/*
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DefaultEnforceMode returns the systems default SELinux mode Enforcing,
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Permissive or Disabled. Note this is is just the default at boot time.
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EnforceMode tells you the systems current mode.
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*/
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func DefaultEnforceMode() int {
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||||
switch readConfig(selinuxTag) {
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||||
case "enforcing":
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||||
return Enforcing
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case "permissive":
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return Permissive
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}
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return Disabled
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||||
}
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||||
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func mcsAdd(mcs string) error {
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||||
state.Lock()
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||||
defer state.Unlock()
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||||
if state.mcsList[mcs] {
|
||||
return fmt.Errorf("MCS Label already exists")
|
||||
}
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||||
state.mcsList[mcs] = true
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||||
return nil
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||||
}
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||||
|
||||
func mcsDelete(mcs string) {
|
||||
state.Lock()
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||||
defer state.Unlock()
|
||||
state.mcsList[mcs] = false
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||||
}
|
||||
|
||||
func intToMcs(id int, catRange uint32) string {
|
||||
var (
|
||||
SETSIZE = int(catRange)
|
||||
TIER = SETSIZE
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||||
ORD = id
|
||||
)
|
||||
|
||||
if id < 1 || id > 523776 {
|
||||
return ""
|
||||
}
|
||||
|
||||
for ORD > TIER {
|
||||
ORD = ORD - TIER
|
||||
TIER--
|
||||
}
|
||||
TIER = SETSIZE - TIER
|
||||
ORD = ORD + TIER
|
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return fmt.Sprintf("s0:c%d,c%d", TIER, ORD)
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}
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|
||||
func uniqMcs(catRange uint32) string {
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||||
var (
|
||||
n uint32
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c1, c2 uint32
|
||||
mcs string
|
||||
)
|
||||
|
||||
for {
|
||||
binary.Read(rand.Reader, binary.LittleEndian, &n)
|
||||
c1 = n % catRange
|
||||
binary.Read(rand.Reader, binary.LittleEndian, &n)
|
||||
c2 = n % catRange
|
||||
if c1 == c2 {
|
||||
continue
|
||||
} else {
|
||||
if c1 > c2 {
|
||||
c1, c2 = c2, c1
|
||||
}
|
||||
}
|
||||
mcs = fmt.Sprintf("s0:c%d,c%d", c1, c2)
|
||||
if err := mcsAdd(mcs); err != nil {
|
||||
continue
|
||||
}
|
||||
break
|
||||
}
|
||||
return mcs
|
||||
}
|
||||
|
||||
/*
|
||||
ReleaseLabel will unreserve the MLS/MCS Level field of the specified label.
|
||||
Allowing it to be used by another process.
|
||||
*/
|
||||
func ReleaseLabel(label string) {
|
||||
if len(label) != 0 {
|
||||
con := strings.SplitN(label, ":", 4)
|
||||
mcsDelete(con[3])
|
||||
}
|
||||
}
|
||||
|
||||
var roFileLabel string
|
||||
|
||||
// ROFileLabel returns the specified SELinux readonly file label
|
||||
func ROFileLabel() (fileLabel string) {
|
||||
return roFileLabel
|
||||
}
|
||||
|
||||
/*
|
||||
ContainerLabels returns an allocated processLabel and fileLabel to be used for
|
||||
container labeling by the calling process.
|
||||
*/
|
||||
func ContainerLabels() (processLabel string, fileLabel string) {
|
||||
var (
|
||||
val, key string
|
||||
bufin *bufio.Reader
|
||||
)
|
||||
|
||||
if !GetEnabled() {
|
||||
return "", ""
|
||||
}
|
||||
lxcPath := fmt.Sprintf("%s/contexts/lxc_contexts", getSELinuxPolicyRoot())
|
||||
in, err := os.Open(lxcPath)
|
||||
if err != nil {
|
||||
return "", ""
|
||||
}
|
||||
defer in.Close()
|
||||
|
||||
bufin = bufio.NewReader(in)
|
||||
|
||||
for done := false; !done; {
|
||||
var line string
|
||||
if line, err = bufin.ReadString('\n'); err != nil {
|
||||
if err == io.EOF {
|
||||
done = true
|
||||
} else {
|
||||
goto exit
|
||||
}
|
||||
}
|
||||
line = strings.TrimSpace(line)
|
||||
if len(line) == 0 {
|
||||
// Skip blank lines
|
||||
continue
|
||||
}
|
||||
if line[0] == ';' || line[0] == '#' {
|
||||
// Skip comments
|
||||
continue
|
||||
}
|
||||
if groups := assignRegex.FindStringSubmatch(line); groups != nil {
|
||||
key, val = strings.TrimSpace(groups[1]), strings.TrimSpace(groups[2])
|
||||
if key == "process" {
|
||||
processLabel = strings.Trim(val, "\"")
|
||||
}
|
||||
if key == "file" {
|
||||
fileLabel = strings.Trim(val, "\"")
|
||||
}
|
||||
if key == "ro_file" {
|
||||
roFileLabel = strings.Trim(val, "\"")
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if processLabel == "" || fileLabel == "" {
|
||||
return "", ""
|
||||
}
|
||||
|
||||
if roFileLabel == "" {
|
||||
roFileLabel = fileLabel
|
||||
}
|
||||
exit:
|
||||
mcs := uniqMcs(1024)
|
||||
scon := NewContext(processLabel)
|
||||
scon["level"] = mcs
|
||||
processLabel = scon.Get()
|
||||
scon = NewContext(fileLabel)
|
||||
scon["level"] = mcs
|
||||
fileLabel = scon.Get()
|
||||
return processLabel, fileLabel
|
||||
}
|
||||
|
||||
// SecurityCheckContext validates that the SELinux label is understood by the kernel
|
||||
func SecurityCheckContext(val string) error {
|
||||
return writeCon(fmt.Sprintf("%s.context", selinuxPath), val)
|
||||
}
|
||||
|
||||
/*
|
||||
CopyLevel returns a label with the MLS/MCS level from src label replaces on
|
||||
the dest label.
|
||||
*/
|
||||
func CopyLevel(src, dest string) (string, error) {
|
||||
if src == "" {
|
||||
return "", nil
|
||||
}
|
||||
if err := SecurityCheckContext(src); err != nil {
|
||||
return "", err
|
||||
}
|
||||
if err := SecurityCheckContext(dest); err != nil {
|
||||
return "", err
|
||||
}
|
||||
scon := NewContext(src)
|
||||
tcon := NewContext(dest)
|
||||
mcsDelete(tcon["level"])
|
||||
mcsAdd(scon["level"])
|
||||
tcon["level"] = scon["level"]
|
||||
return tcon.Get(), nil
|
||||
}
|
||||
|
||||
// Prevent users from relabing system files
|
||||
func badPrefix(fpath string) error {
|
||||
var badprefixes = []string{"/usr"}
|
||||
|
||||
for _, prefix := range badprefixes {
|
||||
if fpath == prefix || strings.HasPrefix(fpath, fmt.Sprintf("%s/", prefix)) {
|
||||
return fmt.Errorf("relabeling content in %s is not allowed", prefix)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// Chcon changes the fpath file object to the SELinux label label.
|
||||
// If the fpath is a directory and recurse is true Chcon will walk the
|
||||
// directory tree setting the label
|
||||
func Chcon(fpath string, label string, recurse bool) error {
|
||||
if label == "" {
|
||||
return nil
|
||||
}
|
||||
if err := badPrefix(fpath); err != nil {
|
||||
return err
|
||||
}
|
||||
callback := func(p string, info os.FileInfo, err error) error {
|
||||
return SetFileLabel(p, label)
|
||||
}
|
||||
|
||||
if recurse {
|
||||
return filepath.Walk(fpath, callback)
|
||||
}
|
||||
|
||||
return SetFileLabel(fpath, label)
|
||||
}
|
||||
|
||||
// DupSecOpt takes an SELinux process label and returns security options that
|
||||
// can will set the SELinux Type and Level for future container processes
|
||||
func DupSecOpt(src string) []string {
|
||||
if src == "" {
|
||||
return nil
|
||||
}
|
||||
con := NewContext(src)
|
||||
if con["user"] == "" ||
|
||||
con["role"] == "" ||
|
||||
con["type"] == "" ||
|
||||
con["level"] == "" {
|
||||
return nil
|
||||
}
|
||||
return []string{"user:" + con["user"],
|
||||
"role:" + con["role"],
|
||||
"type:" + con["type"],
|
||||
"level:" + con["level"]}
|
||||
}
|
||||
|
||||
// DisableSecOpt returns a security opt that can be used to disabling SELinux
|
||||
// labeling support for future container processes
|
||||
func DisableSecOpt() []string {
|
||||
return []string{"disable"}
|
||||
}
|
||||
Reference in New Issue
Block a user