/
prepare.go
611 lines (524 loc) · 18.6 KB
/
prepare.go
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// Copyright (c) 2018, Sylabs Inc. All rights reserved.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.
package singularity
import (
"encoding/json"
"fmt"
"net"
"os"
"path/filepath"
"strings"
"github.com/sylabs/singularity/internal/pkg/buildcfg"
"github.com/sylabs/singularity/internal/pkg/image"
"github.com/sylabs/singularity/internal/pkg/instance"
"github.com/sylabs/singularity/internal/pkg/runtime/engines/config"
"github.com/sylabs/singularity/internal/pkg/runtime/engines/config/starter"
"github.com/sylabs/singularity/internal/pkg/security"
"github.com/sylabs/singularity/internal/pkg/security/seccomp"
"github.com/sylabs/singularity/internal/pkg/syecl"
"github.com/sylabs/singularity/internal/pkg/sylog"
"github.com/sylabs/singularity/internal/pkg/util/capabilities"
"github.com/sylabs/singularity/internal/pkg/util/fs"
"github.com/sylabs/singularity/internal/pkg/util/mainthread"
"github.com/sylabs/singularity/internal/pkg/util/user"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
// prepareUserCaps is responsible for checking that user's requested
// capabilities are authorized
func (e *EngineOperations) prepareUserCaps() error {
uid := os.Getuid()
commonCaps := make([]string, 0)
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
file, err := capabilities.Open(buildcfg.CAPABILITY_FILE, true)
if err != nil {
return err
}
defer file.Close()
pw, err := user.GetPwUID(uint32(uid))
if err != nil {
return err
}
caps, _ := capabilities.Split(e.EngineConfig.GetAddCaps())
caps = append(caps, e.EngineConfig.OciConfig.Process.Capabilities.Permitted...)
authorizedCaps, _ := file.CheckUserCaps(pw.Name, caps)
if len(authorizedCaps) > 0 {
sylog.Debugf("User capabilities %v added", authorizedCaps)
commonCaps = authorizedCaps
}
groups, err := os.Getgroups()
for _, g := range groups {
gr, err := user.GetGrGID(uint32(g))
if err != nil {
sylog.Debugf("Ignoring group %d: %s", g, err)
continue
}
authorizedCaps, _ := file.CheckGroupCaps(gr.Name, caps)
if len(authorizedCaps) > 0 {
sylog.Debugf("%s group capabilities %v added", gr.Name, authorizedCaps)
commonCaps = append(commonCaps, authorizedCaps...)
}
}
commonCaps = capabilities.RemoveDuplicated(commonCaps)
caps, _ = capabilities.Split(e.EngineConfig.GetDropCaps())
for _, cap := range caps {
for i, c := range commonCaps {
if c == cap {
sylog.Debugf("Capability %s dropped", cap)
commonCaps = append(commonCaps[:i], commonCaps[i+1:]...)
break
}
}
}
e.EngineConfig.OciConfig.Process.Capabilities.Permitted = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Effective = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Inheritable = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Bounding = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Ambient = commonCaps
return nil
}
// prepareRootCaps is responsible for setting root capabilities
// based on capability/configuration files and requested capabilities
func (e *EngineOperations) prepareRootCaps() error {
commonCaps := make([]string, 0)
defaultCapabilities := e.EngineConfig.File.RootDefaultCapabilities
uid := e.EngineConfig.GetTargetUID()
gids := e.EngineConfig.GetTargetGID()
if uid != 0 || len(gids) > 0 {
defaultCapabilities = "no"
}
// is no-privs/keep-privs set on command line
if e.EngineConfig.GetNoPrivs() {
sylog.Debugf("--no-privs requested, no new privileges enabled")
defaultCapabilities = "no"
} else if e.EngineConfig.GetKeepPrivs() {
sylog.Debugf("--keep-privs requested")
defaultCapabilities = "full"
}
sylog.Debugf("Root %s capabilities", defaultCapabilities)
// set default capabilities based on configuration file directive
switch defaultCapabilities {
case "full":
e.EngineConfig.OciConfig.SetupPrivileged(true)
commonCaps = e.EngineConfig.OciConfig.Process.Capabilities.Permitted
case "file":
file, err := capabilities.Open(buildcfg.CAPABILITY_FILE, true)
if err != nil {
return err
}
defer file.Close()
commonCaps = append(commonCaps, file.ListUserCaps("root")...)
groups, err := os.Getgroups()
for _, g := range groups {
gr, err := user.GetGrGID(uint32(g))
if err != nil {
sylog.Debugf("Ignoring group %d: %s", g, err)
continue
}
caps := file.ListGroupCaps(gr.Name)
commonCaps = append(commonCaps, caps...)
sylog.Debugf("%s group capabilities %v added", gr.Name, caps)
}
default:
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
}
caps, _ := capabilities.Split(e.EngineConfig.GetAddCaps())
for _, cap := range caps {
found := false
for _, c := range commonCaps {
if c == cap {
found = true
break
}
}
if !found {
sylog.Debugf("Root capability %s added", cap)
commonCaps = append(commonCaps, cap)
}
}
commonCaps = capabilities.RemoveDuplicated(commonCaps)
caps, _ = capabilities.Split(e.EngineConfig.GetDropCaps())
for _, cap := range caps {
for i, c := range commonCaps {
if c == cap {
sylog.Debugf("Root capability %s dropped", cap)
commonCaps = append(commonCaps[:i], commonCaps[i+1:]...)
break
}
}
}
e.EngineConfig.OciConfig.Process.Capabilities.Permitted = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Effective = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Inheritable = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Bounding = commonCaps
e.EngineConfig.OciConfig.Process.Capabilities.Ambient = commonCaps
return nil
}
func (e *EngineOperations) prepareFd() {
fds := make([]int, 0)
if e.EngineConfig.File.UserBindControl {
for _, b := range e.EngineConfig.GetBindPath() {
splitted := strings.Split(b, ":")
src, err := filepath.Abs(splitted[0])
if err != nil {
continue
}
if !fs.IsDir(src) {
continue
}
sylog.Debugf("Open file descriptor for %s", src)
f, err := os.Open(src)
if err != nil {
continue
}
fds = append(fds, int(f.Fd()))
}
}
if !e.EngineConfig.GetContain() {
for _, bindpath := range e.EngineConfig.File.BindPath {
splitted := strings.Split(bindpath, ":")
src := splitted[0]
if !fs.IsDir(src) {
continue
}
sylog.Debugf("Open file descriptor for %s", src)
f, err := os.Open(src)
if err != nil {
continue
}
fds = append(fds, int(f.Fd()))
}
}
for _, path := range e.EngineConfig.File.AutofsBugPath {
if !fs.IsDir(path) {
continue
}
sylog.Debugf("Open file descriptor for %s", path)
f, err := os.Open(path)
if err != nil {
continue
}
fds = append(fds, int(f.Fd()))
}
e.EngineConfig.SetOpenFd(fds)
}
// prepareContainerConfig is responsible for getting and applying user supplied
// configuration for container creation
func (e *EngineOperations) prepareContainerConfig(starterConfig *starter.Config) error {
// always set mount namespace
e.EngineConfig.OciConfig.AddOrReplaceLinuxNamespace(specs.MountNamespace, "")
// if PID namespace is not allowed remove it from namespaces
if !e.EngineConfig.File.AllowPidNs && e.EngineConfig.OciConfig.Linux != nil {
namespaces := e.EngineConfig.OciConfig.Linux.Namespaces
for i, ns := range namespaces {
if ns.Type == specs.PIDNamespace {
sylog.Debugf("Not virtualizing PID namespace by configuration")
e.EngineConfig.OciConfig.Linux.Namespaces = append(namespaces[:i], namespaces[i+1:]...)
break
}
}
}
if os.Getuid() == 0 {
if err := e.prepareRootCaps(); err != nil {
return err
}
} else {
if err := e.prepareUserCaps(); err != nil {
return err
}
}
if e.EngineConfig.File.MountSlave {
starterConfig.SetMountPropagation("slave")
} else {
starterConfig.SetMountPropagation("private")
}
starterConfig.SetInstance(e.EngineConfig.GetInstance())
starterConfig.SetNsFlagsFromSpec(e.EngineConfig.OciConfig.Linux.Namespaces)
// user namespace ID mappings
if e.EngineConfig.OciConfig.Linux != nil {
if err := starterConfig.AddUIDMappings(e.EngineConfig.OciConfig.Linux.UIDMappings); err != nil {
return err
}
if err := starterConfig.AddGIDMappings(e.EngineConfig.OciConfig.Linux.GIDMappings); err != nil {
return err
}
}
param := security.GetParam(e.EngineConfig.GetSecurity(), "selinux")
if param != "" {
sylog.Debugf("Applying SELinux context %s", param)
e.EngineConfig.OciConfig.SetProcessSelinuxLabel(param)
}
param = security.GetParam(e.EngineConfig.GetSecurity(), "apparmor")
if param != "" {
sylog.Debugf("Applying Apparmor profile %s", param)
e.EngineConfig.OciConfig.SetProcessApparmorProfile(param)
}
param = security.GetParam(e.EngineConfig.GetSecurity(), "seccomp")
if param != "" {
sylog.Debugf("Applying seccomp rule from %s", param)
generator := &e.EngineConfig.OciConfig.Generator
if err := seccomp.LoadProfileFromFile(param, generator); err != nil {
return err
}
}
// open file descriptors (autofs bug path)
e.prepareFd()
return nil
}
// prepareInstanceJoinConfig is responsible for getting and applying configuration
// to join a running instance
func (e *EngineOperations) prepareInstanceJoinConfig(starterConfig *starter.Config) error {
name := instance.ExtractName(e.EngineConfig.GetImage())
file, err := instance.Get(name)
if err != nil {
return err
}
// check if SUID workflow is really used with a privileged instance
if !file.PrivilegedPath() && starterConfig.GetIsSUID() {
return fmt.Errorf("try to join unprivileged instance with SUID workflow")
}
instanceEngineConfig := NewConfig()
// extract configuration from instance file
instanceConfig := &config.Common{
EngineConfig: instanceEngineConfig,
}
if err := json.Unmarshal(file.Config, instanceConfig); err != nil {
return err
}
// set namespaces to join
starterConfig.SetNsPathFromSpec(instanceEngineConfig.OciConfig.Linux.Namespaces)
if e.EngineConfig.OciConfig.Process == nil {
e.EngineConfig.OciConfig.Process = &specs.Process{}
}
if e.EngineConfig.OciConfig.Process.Capabilities == nil {
e.EngineConfig.OciConfig.Process.Capabilities = &specs.LinuxCapabilities{}
}
// duplicate instance capabilities
if instanceEngineConfig.OciConfig.Process != nil && instanceEngineConfig.OciConfig.Process.Capabilities != nil {
e.EngineConfig.OciConfig.Process.Capabilities.Permitted = instanceEngineConfig.OciConfig.Process.Capabilities.Permitted
e.EngineConfig.OciConfig.Process.Capabilities.Effective = instanceEngineConfig.OciConfig.Process.Capabilities.Effective
e.EngineConfig.OciConfig.Process.Capabilities.Inheritable = instanceEngineConfig.OciConfig.Process.Capabilities.Inheritable
e.EngineConfig.OciConfig.Process.Capabilities.Bounding = instanceEngineConfig.OciConfig.Process.Capabilities.Bounding
e.EngineConfig.OciConfig.Process.Capabilities.Ambient = instanceEngineConfig.OciConfig.Process.Capabilities.Ambient
}
if os.Getuid() == 0 {
if err := e.prepareRootCaps(); err != nil {
return err
}
} else {
if err := e.prepareUserCaps(); err != nil {
return err
}
}
// restore apparmor profile
param := security.GetParam(e.EngineConfig.GetSecurity(), "apparmor")
if param != "" {
sylog.Debugf("Applying Apparmor profile %s", param)
e.EngineConfig.OciConfig.SetProcessApparmorProfile(param)
} else {
e.EngineConfig.OciConfig.SetProcessApparmorProfile(instanceEngineConfig.OciConfig.Process.ApparmorProfile)
}
// restore selinux context
param = security.GetParam(e.EngineConfig.GetSecurity(), "selinux")
if param != "" {
sylog.Debugf("Applying SELinux context %s", param)
e.EngineConfig.OciConfig.SetProcessSelinuxLabel(param)
} else {
e.EngineConfig.OciConfig.SetProcessSelinuxLabel(instanceEngineConfig.OciConfig.Process.SelinuxLabel)
}
// restore security features
param = security.GetParam(e.EngineConfig.GetSecurity(), "seccomp")
if param != "" {
sylog.Debugf("Applying seccomp rule from %s", param)
generator := &e.EngineConfig.OciConfig.Generator
if err := seccomp.LoadProfileFromFile(param, generator); err != nil {
return err
}
} else {
if instanceEngineConfig.OciConfig.Linux != nil {
if e.EngineConfig.OciConfig.Linux == nil {
e.EngineConfig.OciConfig.Linux = &specs.Linux{}
}
e.EngineConfig.OciConfig.Linux.Seccomp = instanceEngineConfig.OciConfig.Linux.Seccomp
}
}
e.EngineConfig.OciConfig.Process.NoNewPrivileges = instanceEngineConfig.OciConfig.Process.NoNewPrivileges
return nil
}
// PrepareConfig checks and prepares the runtime engine config
func (e *EngineOperations) PrepareConfig(masterConn net.Conn, starterConfig *starter.Config) error {
if e.CommonConfig.EngineName != Name {
return fmt.Errorf("incorrect engine")
}
configurationFile := buildcfg.SYSCONFDIR + "/singularity/singularity.conf"
if err := config.Parser(configurationFile, e.EngineConfig.File); err != nil {
return fmt.Errorf("Unable to parse singularity.conf file: %s", err)
}
if !e.EngineConfig.File.AllowSetuid && starterConfig.GetIsSUID() {
return fmt.Errorf("SUID workflow disabled by administrator")
}
if starterConfig.GetIsSUID() {
// check for ownership of singularity.conf
if !fs.IsOwner(configurationFile, 0) {
return fmt.Errorf("%s must be owned by root", configurationFile)
}
// check for ownership of capability.json
if !fs.IsOwner(buildcfg.CAPABILITY_FILE, 0) {
return fmt.Errorf("%s must be owned by root", buildcfg.CAPABILITY_FILE)
}
// check for ownership of ecl.toml
if !fs.IsOwner(buildcfg.ECL_FILE, 0) {
return fmt.Errorf("%s must be owned by root", buildcfg.ECL_FILE)
}
}
// Save the current working directory to restore it in stage 2
// for relative bind paths
if pwd, err := os.Getwd(); err == nil {
e.EngineConfig.SetCwd(pwd)
} else {
sylog.Warningf("can't determine current working directory")
e.EngineConfig.SetCwd("/")
}
if e.EngineConfig.OciConfig.Process == nil {
e.EngineConfig.OciConfig.Process = &specs.Process{}
}
if e.EngineConfig.OciConfig.Process.Capabilities == nil {
e.EngineConfig.OciConfig.Process.Capabilities = &specs.LinuxCapabilities{}
}
uid := e.EngineConfig.GetTargetUID()
gids := e.EngineConfig.GetTargetGID()
if os.Getuid() == 0 && (uid != 0 || len(gids) > 0) {
starterConfig.SetTargetUID(uid)
starterConfig.SetTargetGID(gids)
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
}
if e.EngineConfig.GetInstanceJoin() {
if err := e.prepareInstanceJoinConfig(starterConfig); err != nil {
return err
}
} else {
if err := e.prepareContainerConfig(starterConfig); err != nil {
return err
}
if err := e.loadImages(); err != nil {
return err
}
}
starterConfig.SetNoNewPrivs(e.EngineConfig.OciConfig.Process.NoNewPrivileges)
if e.EngineConfig.OciConfig.Process != nil && e.EngineConfig.OciConfig.Process.Capabilities != nil {
starterConfig.SetCapabilities(capabilities.Permitted, e.EngineConfig.OciConfig.Process.Capabilities.Permitted)
starterConfig.SetCapabilities(capabilities.Effective, e.EngineConfig.OciConfig.Process.Capabilities.Effective)
starterConfig.SetCapabilities(capabilities.Inheritable, e.EngineConfig.OciConfig.Process.Capabilities.Inheritable)
starterConfig.SetCapabilities(capabilities.Bounding, e.EngineConfig.OciConfig.Process.Capabilities.Bounding)
starterConfig.SetCapabilities(capabilities.Ambient, e.EngineConfig.OciConfig.Process.Capabilities.Ambient)
}
return nil
}
func (e *EngineOperations) loadImages() error {
images := make([]image.Image, 0)
// load rootfs image
writable := e.EngineConfig.GetWritableImage()
img, err := e.loadImage(e.EngineConfig.GetImage(), writable)
if err != nil {
return err
}
if writable && !img.Writable {
sylog.Warningf("Can't set writable flag on image, no write permissions")
e.EngineConfig.SetWritableImage(false)
}
// sandbox are handled differently for security reasons
if img.Type == image.SANDBOX {
if img.Path == "/" {
return fmt.Errorf("/ as sandbox is not authorized")
}
if err := os.Chdir(img.Source); err != nil {
return err
}
cwd, err := os.Getwd()
if err != nil {
return fmt.Errorf("failed to determine current working directory: %s", err)
}
if cwd != img.Path {
return fmt.Errorf("path mismatch for sandbox %s != %s", cwd, img.Path)
}
}
if img.Type == image.SIF {
// query the ECL module, proceed if an ecl config file is found
ecl, err := syecl.LoadConfig(buildcfg.ECL_FILE)
if err == nil {
if err = ecl.ValidateConfig(); err != nil {
return err
}
_, err := ecl.ShouldRunFp(img.File)
if err != nil {
return err
}
}
}
img.RootFS = true
images = append(images, *img)
// load overlay images
for _, overlayImg := range e.EngineConfig.GetOverlayImage() {
writable := true
splitted := strings.SplitN(overlayImg, ":", 2)
if len(splitted) == 2 {
if splitted[1] == "ro" {
writable = false
}
}
img, err := e.loadImage(splitted[0], writable)
if err != nil {
return fmt.Errorf("failed to open overlay image %s: %s", splitted[0], err)
}
images = append(images, *img)
}
e.EngineConfig.SetImageList(images)
return nil
}
func (e *EngineOperations) loadImage(path string, writable bool) (*image.Image, error) {
imgObject, err := image.Init(path, writable)
if err != nil {
return nil, err
}
link, err := mainthread.Readlink(imgObject.Source)
if link != imgObject.Path {
return nil, fmt.Errorf("resolved path %s doesn't match with opened path %s", imgObject.Path, link)
}
if len(e.EngineConfig.File.LimitContainerPaths) != 0 {
if authorized, err := imgObject.AuthorizedPath(e.EngineConfig.File.LimitContainerPaths); err != nil {
return nil, err
} else if !authorized {
return nil, fmt.Errorf("Singularity image is not in an allowed configured path")
}
}
if len(e.EngineConfig.File.LimitContainerGroups) != 0 {
if authorized, err := imgObject.AuthorizedGroup(e.EngineConfig.File.LimitContainerGroups); err != nil {
return nil, err
} else if !authorized {
return nil, fmt.Errorf("Singularity image is not owned by required group(s)")
}
}
if len(e.EngineConfig.File.LimitContainerOwners) != 0 {
if authorized, err := imgObject.AuthorizedOwner(e.EngineConfig.File.LimitContainerOwners); err != nil {
return nil, err
} else if !authorized {
return nil, fmt.Errorf("Singularity image is not owned by required user(s)")
}
}
switch imgObject.Type {
case image.SANDBOX:
if !e.EngineConfig.File.AllowContainerDir {
return nil, fmt.Errorf("configuration disallows users from running sandbox based containers")
}
case image.EXT3:
if !e.EngineConfig.File.AllowContainerExtfs {
return nil, fmt.Errorf("configuration disallows users from running extFS based containers")
}
case image.SQUASHFS:
if !e.EngineConfig.File.AllowContainerSquashfs {
return nil, fmt.Errorf("configuration disallows users from running squashFS based containers")
}
}
return imgObject, nil
}