diff options
Diffstat (limited to 'vendor')
-rw-r--r-- | vendor/github.com/opencontainers/selinux/go-selinux/label/label_selinux.go | 3 | ||||
-rw-r--r-- | vendor/github.com/opencontainers/selinux/go-selinux/selinux.go | 272 |
2 files changed, 200 insertions, 75 deletions
diff --git a/vendor/github.com/opencontainers/selinux/go-selinux/label/label_selinux.go b/vendor/github.com/opencontainers/selinux/go-selinux/label/label_selinux.go index c008a387b..f7b238529 100644 --- a/vendor/github.com/opencontainers/selinux/go-selinux/label/label_selinux.go +++ b/vendor/github.com/opencontainers/selinux/go-selinux/label/label_selinux.go @@ -87,9 +87,6 @@ func FormatMountLabel(src, mountLabel string) string { // SetProcessLabel takes a process label and tells the kernel to assign the // label to the next program executed by the current process. func SetProcessLabel(processLabel string) error { - if processLabel == "" { - return nil - } return selinux.SetExecLabel(processLabel) } diff --git a/vendor/github.com/opencontainers/selinux/go-selinux/selinux.go b/vendor/github.com/opencontainers/selinux/go-selinux/selinux.go index de9316c2e..6068e84a5 100644 --- a/vendor/github.com/opencontainers/selinux/go-selinux/selinux.go +++ b/vendor/github.com/opencontainers/selinux/go-selinux/selinux.go @@ -4,10 +4,13 @@ package selinux import ( "bufio" + "bytes" "crypto/rand" "encoding/binary" + "errors" "fmt" "io" + "io/ioutil" "os" "path/filepath" "regexp" @@ -23,14 +26,16 @@ const ( // Permissive constant to indicate SELinux is in permissive mode Permissive = 0 // Disabled constant to indicate SELinux is disabled - Disabled = -1 + Disabled = -1 + selinuxDir = "/etc/selinux/" selinuxConfig = selinuxDir + "config" + selinuxfsMount = "/sys/fs/selinux" selinuxTypeTag = "SELINUXTYPE" selinuxTag = "SELINUX" - selinuxPath = "/sys/fs/selinux" xattrNameSelinux = "security.selinux" stRdOnly = 0x01 + selinuxfsMagic = 0xf97cff8c ) type selinuxState struct { @@ -43,7 +48,13 @@ type selinuxState struct { } var ( + // ErrMCSAlreadyExists is returned when trying to allocate a duplicate MCS. + ErrMCSAlreadyExists = errors.New("MCS label already exists") + // ErrEmptyPath is returned when an empty path has been specified. + ErrEmptyPath = errors.New("empty path") + assignRegex = regexp.MustCompile(`^([^=]+)=(.*)$`) + roFileLabel string state = selinuxState{ mcsList: make(map[string]bool), } @@ -91,49 +102,93 @@ func (s *selinuxState) setSELinuxfs(selinuxfs string) string { return s.selinuxfs } -func (s *selinuxState) getSELinuxfs() string { - s.Lock() - selinuxfs := s.selinuxfs - selinuxfsSet := s.selinuxfsSet - s.Unlock() - if selinuxfsSet { - return selinuxfs +func verifySELinuxfsMount(mnt string) bool { + var buf syscall.Statfs_t + for { + err := syscall.Statfs(mnt, &buf) + if err == nil { + break + } + if err == syscall.EAGAIN { + continue + } + return false + } + if uint32(buf.Type) != uint32(selinuxfsMagic) { + return false + } + if (buf.Flags & stRdOnly) != 0 { + return false + } + + return true +} + +func findSELinuxfs() string { + // fast path: check the default mount first + if verifySELinuxfsMount(selinuxfsMount) { + return selinuxfsMount + } + + // check if selinuxfs is available before going the slow path + fs, err := ioutil.ReadFile("/proc/filesystems") + if err != nil { + return "" + } + if !bytes.Contains(fs, []byte("\tselinuxfs\n")) { + return "" } - selinuxfs = "" + // slow path: try to find among the mounts f, err := os.Open("/proc/self/mountinfo") if err != nil { - return selinuxfs + return "" } defer f.Close() scanner := bufio.NewScanner(f) - for scanner.Scan() { - txt := scanner.Text() - // Safe as mountinfo encodes mountpoints with spaces as \040. - sepIdx := strings.Index(txt, " - ") - if sepIdx == -1 { - continue + for { + mnt := findSELinuxfsMount(scanner) + if mnt == "" { // error or not found + return "" + } + if verifySELinuxfsMount(mnt) { + return mnt } - if !strings.Contains(txt[sepIdx:], "selinuxfs") { + } +} + +// findSELinuxfsMount returns a next selinuxfs mount point found, +// if there is one, or an empty string in case of EOF or error. +func findSELinuxfsMount(s *bufio.Scanner) string { + for s.Scan() { + txt := s.Text() + // The first field after - is fs type. + // Safe as spaces in mountpoints are encoded as \040 + if !strings.Contains(txt, " - selinuxfs ") { continue } - fields := strings.Split(txt, " ") - if len(fields) < 5 { + const mPos = 5 // mount point is 5th field + fields := strings.SplitN(txt, " ", mPos+1) + if len(fields) < mPos+1 { continue } - selinuxfs = fields[4] - break + return fields[mPos-1] } - if selinuxfs != "" { - var buf syscall.Statfs_t - syscall.Statfs(selinuxfs, &buf) - if (buf.Flags & stRdOnly) == 1 { - selinuxfs = "" - } + return "" +} + +func (s *selinuxState) getSELinuxfs() string { + s.Lock() + selinuxfs := s.selinuxfs + selinuxfsSet := s.selinuxfsSet + s.Unlock() + if selinuxfsSet { + return selinuxfs } - return s.setSELinuxfs(selinuxfs) + + return s.setSELinuxfs(findSELinuxfs()) } // getSelinuxMountPoint returns the path to the mountpoint of an selinuxfs @@ -150,7 +205,7 @@ func GetEnabled() bool { return state.getEnabled() } -func readConfig(target string) (value string) { +func readConfig(target string) string { var ( val, key string bufin *bufio.Reader @@ -192,30 +247,42 @@ func readConfig(target string) (value string) { } func getSELinuxPolicyRoot() string { - return selinuxDir + readConfig(selinuxTypeTag) + return filepath.Join(selinuxDir, readConfig(selinuxTypeTag)) } -func readCon(name string) (string, error) { - var val string +func readCon(fpath string) (string, error) { + if fpath == "" { + return "", ErrEmptyPath + } - in, err := os.Open(name) + in, err := os.Open(fpath) if err != nil { return "", err } defer in.Close() - _, err = fmt.Fscanf(in, "%s", &val) - return val, err + var retval string + if _, err := fmt.Fscanf(in, "%s", &retval); err != nil { + return "", err + } + return strings.Trim(retval, "\x00"), nil } // SetFileLabel sets the SELinux label for this path or returns an error. -func SetFileLabel(path string, label string) error { - return lsetxattr(path, xattrNameSelinux, []byte(label), 0) +func SetFileLabel(fpath string, label string) error { + if fpath == "" { + return ErrEmptyPath + } + return lsetxattr(fpath, xattrNameSelinux, []byte(label), 0) } // FileLabel returns the SELinux label for this path or returns an error. -func FileLabel(path string) (string, error) { - label, err := lgetxattr(path, xattrNameSelinux) +func FileLabel(fpath string) (string, error) { + if fpath == "" { + return "", ErrEmptyPath + } + + label, err := lgetxattr(fpath, xattrNameSelinux) if err != nil { return "", err } @@ -260,8 +327,12 @@ func ExecLabel() (string, error) { return readCon(fmt.Sprintf("/proc/self/task/%d/attr/exec", syscall.Gettid())) } -func writeCon(name string, val string) error { - out, err := os.OpenFile(name, os.O_WRONLY, 0) +func writeCon(fpath string, val string) error { + if fpath == "" { + return ErrEmptyPath + } + + out, err := os.OpenFile(fpath, os.O_WRONLY, 0) if err != nil { return err } @@ -276,6 +347,37 @@ func writeCon(name string, val string) error { } /* +CanonicalizeContext takes a context string and writes it to the kernel +the function then returns the context that the kernel will use. This function +can be used to see if two contexts are equivalent +*/ +func CanonicalizeContext(val string) (string, error) { + return readWriteCon(filepath.Join(getSelinuxMountPoint(), "context"), val) +} + +func readWriteCon(fpath string, val string) (string, error) { + if fpath == "" { + return "", ErrEmptyPath + } + f, err := os.OpenFile(fpath, os.O_RDWR, 0) + if err != nil { + return "", err + } + defer f.Close() + + _, err = f.Write([]byte(val)) + if err != nil { + return "", err + } + + var retval string + if _, err := fmt.Fscanf(f, "%s", &retval); err != nil { + return "", err + } + return strings.Trim(retval, "\x00"), nil +} + +/* SetExecLabel sets the SELinux label that the kernel will use for any programs that are executed by the current process thread, or an error. */ @@ -285,7 +387,10 @@ func SetExecLabel(label string) error { // Get returns the Context as a string func (c Context) Get() string { - return fmt.Sprintf("%s:%s:%s:%s", c["user"], c["role"], c["type"], c["level"]) + if c["level"] != "" { + return fmt.Sprintf("%s:%s:%s:%s", c["user"], c["role"], c["type"], c["level"]) + } + return fmt.Sprintf("%s:%s:%s", c["user"], c["role"], c["type"]) } // NewContext creates a new Context struct from the specified label @@ -297,7 +402,9 @@ func NewContext(label string) Context { c["user"] = con[0] c["role"] = con[1] c["type"] = con[2] - c["level"] = con[3] + if len(con) > 3 { + c["level"] = con[3] + } } return c } @@ -306,12 +413,14 @@ func NewContext(label string) Context { func ReserveLabel(label string) { if len(label) != 0 { con := strings.SplitN(label, ":", 4) - mcsAdd(con[3]) + if len(con) > 3 { + mcsAdd(con[3]) + } } } func selinuxEnforcePath() string { - return fmt.Sprintf("%s/enforce", selinuxPath) + return fmt.Sprintf("%s/enforce", getSelinuxMountPoint()) } // EnforceMode returns the current SELinux mode Enforcing, Permissive, Disabled @@ -354,16 +463,22 @@ func DefaultEnforceMode() int { } func mcsAdd(mcs string) error { + if mcs == "" { + return nil + } state.Lock() defer state.Unlock() if state.mcsList[mcs] { - return fmt.Errorf("MCS Label already exists") + return ErrMCSAlreadyExists } state.mcsList[mcs] = true return nil } func mcsDelete(mcs string) { + if mcs == "" { + return + } state.Lock() defer state.Unlock() state.mcsList[mcs] = false @@ -424,14 +539,14 @@ Allowing it to be used by another process. func ReleaseLabel(label string) { if len(label) != 0 { con := strings.SplitN(label, ":", 4) - mcsDelete(con[3]) + if len(con) > 3 { + mcsDelete(con[3]) + } } } -var roFileLabel string - // ROFileLabel returns the specified SELinux readonly file label -func ROFileLabel() (fileLabel string) { +func ROFileLabel() string { return roFileLabel } @@ -497,23 +612,25 @@ func ContainerLabels() (processLabel string, fileLabel string) { roFileLabel = fileLabel } exit: - mcs := uniqMcs(1024) scon := NewContext(processLabel) - scon["level"] = mcs - processLabel = scon.Get() - scon = NewContext(fileLabel) - scon["level"] = mcs - fileLabel = scon.Get() + if scon["level"] != "" { + mcs := uniqMcs(1024) + 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) + return writeCon(fmt.Sprintf("%s/context", getSelinuxMountPoint()), val) } /* -CopyLevel returns a label with the MLS/MCS level from src label replaces on +CopyLevel returns a label with the MLS/MCS level from src label replaced on the dest label. */ func CopyLevel(src, dest string) (string, error) { @@ -536,20 +653,26 @@ func CopyLevel(src, dest string) (string, error) { // Prevent users from relabing system files func badPrefix(fpath string) error { - var badprefixes = []string{"/usr"} + if fpath == "" { + return ErrEmptyPath + } - for _, prefix := range badprefixes { - if fpath == prefix || strings.HasPrefix(fpath, fmt.Sprintf("%s/", prefix)) { + badPrefixes := []string{"/usr"} + for _, prefix := range badPrefixes { + if strings.HasPrefix(fpath, 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 +// Chcon changes the `fpath` file object to the SELinux label `label`. +// If `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 fpath == "" { + return ErrEmptyPath + } if label == "" { return nil } @@ -568,7 +691,7 @@ func Chcon(fpath string, label string, recurse bool) error { } // DupSecOpt takes an SELinux process label and returns security options that -// can will set the SELinux Type and Level for future container processes +// can be used to set the SELinux Type and Level for future container processes. func DupSecOpt(src string) []string { if src == "" { return nil @@ -576,18 +699,23 @@ func DupSecOpt(src string) []string { con := NewContext(src) if con["user"] == "" || con["role"] == "" || - con["type"] == "" || - con["level"] == "" { + con["type"] == "" { return nil } - return []string{"user:" + con["user"], + dup := []string{"user:" + con["user"], "role:" + con["role"], "type:" + con["type"], - "level:" + con["level"]} + } + + if con["level"] != "" { + dup = append(dup, "level:"+con["level"]) + } + + return dup } -// DisableSecOpt returns a security opt that can be used to disabling SELinux -// labeling support for future container processes +// DisableSecOpt returns a security opt that can be used to disable SELinux +// labeling support for future container processes. func DisableSecOpt() []string { return []string{"disable"} } |