Merge pull request #5448 from crosbymichael/selinux-defaults

Add selinux label support for processes and mount

label/label.go

@@ -24,3 +24,7 @@ func GetPidCon(pid int) (string, error) {
 
 func Init() {
 }
+
+func ReserveLabel(label string) error {
+	return nil
+}

label/label_selinux.go

@@ -4,8 +4,9 @@ package label
 
 import (
 	"fmt"
-	"github.com/dotcloud/docker/pkg/selinux"
 	"strings"
+
+	"github.com/dotcloud/docker/pkg/selinux"
 )
 
 func GenLabels(options string) (string, string, error) {
@@ -32,13 +33,13 @@ func GenLabels(options string) (string, string, error) {
 	return processLabel, mountLabel, err
 }
 
-func FormatMountLabel(src string, mountLabel string) string {
+func FormatMountLabel(src, mountLabel string) string {
-	if selinux.SelinuxEnabled() && mountLabel != "" {
+	if mountLabel != "" {
 		switch src {
 		case "":
-			src = fmt.Sprintf("%s,context=%s", src, mountLabel)
+			src = fmt.Sprintf("context=%q", mountLabel)
 		default:
-			src = fmt.Sprintf("context=%s", mountLabel)
+			src = fmt.Sprintf("%s,context=%q", src, mountLabel)
 		}
 	}
 	return src
@@ -75,3 +76,8 @@ func GetPidCon(pid int) (string, error) {
 func Init() {
 	selinux.SelinuxEnabled()
 }
+
+func ReserveLabel(label string) error {
+	selinux.ReserveLabel(label)
+	return nil
+}

libcontainer/mount/init.go

@@ -4,14 +4,15 @@ package mount
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+
 	"github.com/dotcloud/docker/pkg/label"
 	"github.com/dotcloud/docker/pkg/libcontainer"
 	"github.com/dotcloud/docker/pkg/libcontainer/mount/nodes"
 	"github.com/dotcloud/docker/pkg/libcontainer/security/restrict"
 	"github.com/dotcloud/docker/pkg/system"
-	"os"
-	"path/filepath"
-	"syscall"
 )
 
 // default mount point flags
@@ -130,11 +131,12 @@ func newSystemMounts(rootfs, mountLabel string, mounts libcontainer.Mounts) []mo
 	}
 
 	if len(mounts.OfType("devtmpfs")) == 1 {
-		systemMounts = append(systemMounts, mount{source: "tmpfs", path: filepath.Join(rootfs, "dev"), device: "tmpfs", flags: syscall.MS_NOSUID | syscall.MS_STRICTATIME, data: "mode=755"})
+		systemMounts = append(systemMounts, mount{source: "tmpfs", path: filepath.Join(rootfs, "dev"), device: "tmpfs", flags: syscall.MS_NOSUID | syscall.MS_STRICTATIME, data: label.FormatMountLabel("mode=755", mountLabel)})
 	}
 	systemMounts = append(systemMounts,
 		mount{source: "shm", path: filepath.Join(rootfs, "dev", "shm"), device: "tmpfs", flags: defaultMountFlags, data: label.FormatMountLabel("mode=1777,size=65536k", mountLabel)},
-		mount{source: "devpts", path: filepath.Join(rootfs, "dev", "pts"), device: "devpts", flags: syscall.MS_NOSUID | syscall.MS_NOEXEC, data: label.FormatMountLabel("newinstance,ptmxmode=0666,mode=620,gid=5", mountLabel)})
+		mount{source: "devpts", path: filepath.Join(rootfs, "dev", "pts"), device: "devpts", flags: syscall.MS_NOSUID | syscall.MS_NOEXEC, data: label.FormatMountLabel("newinstance,ptmxmode=0666,mode=620,gid=5", mountLabel)},
+	)
 
 	if len(mounts.OfType("sysfs")) == 1 {
 		systemMounts = append(systemMounts, mount{source: "sysfs", path: filepath.Join(rootfs, "sys"), device: "sysfs", flags: defaultMountFlags})

libcontainer/nsinit/init.go

@@ -75,8 +75,9 @@ func (ns *linuxNs) Init(container *libcontainer.Container, uncleanRootfs, consol
 		}
 	}
 	runtime.LockOSThread()
+
 	if err := label.SetProcessLabel(container.Context["process_label"]); err != nil {
-		return fmt.Errorf("SetProcessLabel label %s", err)
+		return fmt.Errorf("set process label %s", err)
 	}
 	ns.logger.Printf("execing %s\n", args[0])
 	return system.Execv(args[0], args[0:], container.Env)

selinux/selinux.go

@@ -146,15 +146,15 @@ func Setfilecon(path string, scon string) error {
 }
 
 func Setfscreatecon(scon string) error {
-	return writeCon("/proc/self/attr/fscreate", scon)
+	return writeCon(fmt.Sprintf("/proc/self/task/%d/attr/fscreate", system.Gettid()), scon)
 }
 
 func Getfscreatecon() (string, error) {
-	return readCon("/proc/self/attr/fscreate")
+	return readCon(fmt.Sprintf("/proc/self/task/%d/attr/fscreate", system.Gettid()))
 }
 
 func getcon() (string, error) {
-	return readCon("/proc/self/attr/current")
+	return readCon(fmt.Sprintf("/proc/self/task/%d/attr/current", system.Gettid()))
 }
 
 func Getpidcon(pid int) (string, error) {
@@ -204,6 +204,13 @@ func NewContext(scon string) SELinuxContext {
 	return c
 }
 
+func ReserveLabel(scon string) {
+	if len(scon) != 0 {
+		con := strings.SplitN(scon, ":", 4)
+		mcsAdd(con[3])
+	}
+}
+
 func SelinuxGetEnforce() int {
 	var enforce int
 
@@ -229,8 +236,12 @@ func SelinuxGetEnforceMode() int {
 	return Disabled
 }
 
-func mcsAdd(mcs string) {
+func mcsAdd(mcs string) error {
+	if mcsList[mcs] {
+		return fmt.Errorf("MCS Label already exists")
+	}
 	mcsList[mcs] = true
+	return nil
 }
 
 func mcsDelete(mcs string) {
@@ -283,15 +294,21 @@ func uniqMcs(catRange uint32) string {
 			}
 		}
 		mcs = fmt.Sprintf("s0:c%d,c%d", c1, c2)
-		if mcsExists(mcs) {
+		if err := mcsAdd(mcs); err != nil {
 			continue
 		}
-		mcsAdd(mcs)
 		break
 	}
 	return mcs
 }
 
+func FreeLxcContexts(scon string) {
+	if len(scon) != 0 {
+		con := strings.SplitN(scon, ":", 4)
+		mcsDelete(con[3])
+	}
+}
+
 func GetLxcContexts() (processLabel string, fileLabel string) {
 	var (
 		val, key string
@@ -344,7 +361,8 @@ func GetLxcContexts() (processLabel string, fileLabel string) {
 	}
 
 exit:
-	mcs := IntToMcs(os.Getpid(), 1024)
+	//	mcs := IntToMcs(os.Getpid(), 1024)
+	mcs := uniqMcs(1024)
 	scon := NewContext(processLabel)
 	scon["level"] = mcs
 	processLabel = scon.Get()
@@ -373,6 +391,8 @@ func CopyLevel(src, dest string) (string, error) {
 	}
 	scon := NewContext(src)
 	tcon := NewContext(dest)
+	mcsDelete(tcon["level"])
+	mcsAdd(scon["level"])
 	tcon["level"] = scon["level"]
 	return tcon.Get(), nil
 }

selinux/selinux_test.go

@@ -31,9 +31,11 @@ func TestSELinux(t *testing.T) {
 		plabel, flabel = selinux.GetLxcContexts()
 		t.Log(plabel)
 		t.Log(flabel)
+		selinux.FreeLxcContexts(plabel)
 		plabel, flabel = selinux.GetLxcContexts()
 		t.Log(plabel)
 		t.Log(flabel)
+		selinux.FreeLxcContexts(plabel)
 		t.Log("getenforce ", selinux.SelinuxGetEnforce())
 		t.Log("getenforcemode ", selinux.SelinuxGetEnforceMode())
 		pid := os.Getpid()