selinux.Chcon should check legal rather then just label.Relabel

Since label.Relabel ends up calling into selinux.chcon, we should
do the check for invalid directories under chcon. This will allow
the selinux.Chcon function to also be verified.

Signed-off-by: Daniel J Walsh <[email protected]>

Author: rhatdan

go-selinux/label/label_linux.go

@@ -3,8 +3,6 @@ package label
 import (
 	"errors"
 	"fmt"
-	"os"
-	"os/user"
 	"strings"
 
 	"github.com/opencontainers/selinux/go-selinux"
@@ -113,50 +111,6 @@ func Relabel(path string, fileLabel string, shared bool) error {
 		return nil
 	}
 
-	exclude_paths := map[string]bool{
-		"/":           true,
-		"/bin":        true,
-		"/boot":       true,
-		"/dev":        true,
-		"/etc":        true,
-		"/etc/passwd": true,
-		"/etc/pki":    true,
-		"/etc/shadow": true,
-		"/home":       true,
-		"/lib":        true,
-		"/lib64":      true,
-		"/media":      true,
-		"/opt":        true,
-		"/proc":       true,
-		"/root":       true,
-		"/run":        true,
-		"/sbin":       true,
-		"/srv":        true,
-		"/sys":        true,
-		"/tmp":        true,
-		"/usr":        true,
-		"/var":        true,
-		"/var/lib":    true,
-		"/var/log":    true,
-	}
-
-	if home := os.Getenv("HOME"); home != "" {
-		exclude_paths[home] = true
-	}
-
-	if sudoUser := os.Getenv("SUDO_USER"); sudoUser != "" {
-		if usr, err := user.Lookup(sudoUser); err == nil {
-			exclude_paths[usr.HomeDir] = true
-		}
-	}
-
-	if path != "/" {
-		path = strings.TrimSuffix(path, "/")
-	}
-	if exclude_paths[path] {
-		return fmt.Errorf("SELinux relabeling of %s is not allowed", path)
-	}
-
 	if shared {
 		c, err := selinux.NewContext(fileLabel)
 		if err != nil {

go-selinux/selinux_linux.go

@@ -11,6 +11,7 @@ import (
 	"io/ioutil"
 	"math/big"
 	"os"
+	"os/user"
 	"path"
 	"path/filepath"
 	"strconv"
@@ -1083,6 +1084,50 @@ func chcon(fpath string, label string, recurse bool) error {
 		return nil
 	}
 
+	exclude_paths := map[string]bool{
+		"/":           true,
+		"/bin":        true,
+		"/boot":       true,
+		"/dev":        true,
+		"/etc":        true,
+		"/etc/passwd": true,
+		"/etc/pki":    true,
+		"/etc/shadow": true,
+		"/home":       true,
+		"/lib":        true,
+		"/lib64":      true,
+		"/media":      true,
+		"/opt":        true,
+		"/proc":       true,
+		"/root":       true,
+		"/run":        true,
+		"/sbin":       true,
+		"/srv":        true,
+		"/sys":        true,
+		"/tmp":        true,
+		"/usr":        true,
+		"/var":        true,
+		"/var/lib":    true,
+		"/var/log":    true,
+	}
+
+	if home := os.Getenv("HOME"); home != "" {
+		exclude_paths[home] = true
+	}
+
+	if sudoUser := os.Getenv("SUDO_USER"); sudoUser != "" {
+		if usr, err := user.Lookup(sudoUser); err == nil {
+			exclude_paths[usr.HomeDir] = true
+		}
+	}
+
+	if fpath != "/" {
+		fpath = strings.TrimSuffix(fpath, "/")
+	}
+	if exclude_paths[fpath] {
+		return fmt.Errorf("SELinux relabeling of %s is not allowed", fpath)
+	}
+
 	if !recurse {
 		return setFileLabel(fpath, label)
 	}