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// Copyright (c) 2018-2023, Sylabs Inc. All rights reserved.
// Copyright (c) Contributors to the Apptainer project, established as
// Apptainer a Series of LF Projects LLC.
// Copyright (c) 2020, Control Command 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 (
"bufio"
"context"
"encoding/json"
"errors"
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
"syscall"
"github.com/ProtonMail/go-crypto/openpgp"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/sylabs/singularity/v4/internal/pkg/buildcfg"
"github.com/sylabs/singularity/v4/internal/pkg/cgroups"
fakerootutil "github.com/sylabs/singularity/v4/internal/pkg/fakeroot"
"github.com/sylabs/singularity/v4/internal/pkg/instance"
"github.com/sylabs/singularity/v4/internal/pkg/plugin"
"github.com/sylabs/singularity/v4/internal/pkg/runtime/engine/config/starter"
"github.com/sylabs/singularity/v4/internal/pkg/security"
"github.com/sylabs/singularity/v4/internal/pkg/security/seccomp"
"github.com/sylabs/singularity/v4/internal/pkg/syecl"
"github.com/sylabs/singularity/v4/internal/pkg/sypgp"
"github.com/sylabs/singularity/v4/internal/pkg/util/fs"
"github.com/sylabs/singularity/v4/internal/pkg/util/fs/overlay"
"github.com/sylabs/singularity/v4/internal/pkg/util/mainthread"
"github.com/sylabs/singularity/v4/internal/pkg/util/user"
"github.com/sylabs/singularity/v4/pkg/image"
fakerootcallback "github.com/sylabs/singularity/v4/pkg/plugin/callback/runtime/fakeroot"
"github.com/sylabs/singularity/v4/pkg/runtime/engine/config"
singularityConfig "github.com/sylabs/singularity/v4/pkg/runtime/engine/singularity/config"
"github.com/sylabs/singularity/v4/pkg/sylog"
"github.com/sylabs/singularity/v4/pkg/util/capabilities"
"github.com/sylabs/singularity/v4/pkg/util/fs/proc"
"github.com/sylabs/singularity/v4/pkg/util/namespaces"
"github.com/sylabs/singularity/v4/pkg/util/singularityconf"
"golang.org/x/sys/unix"
)
var nsProcName = map[specs.LinuxNamespaceType]string{
specs.PIDNamespace: "pid",
specs.UTSNamespace: "uts",
specs.IPCNamespace: "ipc",
specs.MountNamespace: "mnt",
specs.CgroupNamespace: "cgroup",
specs.NetworkNamespace: "net",
specs.UserNamespace: "user",
}
// PrepareConfig is called during stage1 to validate and prepare
// container configuration. It is responsible for singularity
// configuration file parsing, handling user input, reading capabilities,
// and checking what namespaces are required.
//
// No additional privileges can be gained as any of them are already
// dropped by the time PrepareConfig is called.
func (e *EngineOperations) PrepareConfig(starterConfig *starter.Config) error {
var err error
if e.CommonConfig.EngineName != singularityConfig.Name {
return fmt.Errorf("incorrect engine")
}
if e.EngineConfig.OciConfig.Generator.Config != &e.EngineConfig.OciConfig.Spec {
return fmt.Errorf("bad engine configuration provided")
}
configurationFile := buildcfg.SINGULARITY_CONF_FILE
if buildcfg.SINGULARITY_SUID_INSTALL == 0 || os.Geteuid() == 0 {
configFile := e.EngineConfig.GetConfigurationFile()
if configFile != "" {
configurationFile = configFile
}
}
e.EngineConfig.File, err = singularityconf.Parse(configurationFile)
if 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 if not set
if e.EngineConfig.GetCwd() == "" {
if cwd, err := os.Getwd(); err == nil {
e.EngineConfig.SetCwd(cwd)
} 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{}
}
if len(e.EngineConfig.OciConfig.Process.Args) == 0 {
return fmt.Errorf("container process arguments not found")
}
uid := e.EngineConfig.GetTargetUID()
gids := e.EngineConfig.GetTargetGID()
useTargetIDs := e.EngineConfig.GetFakeroot()
if os.Getuid() == 0 && (uid != 0 || len(gids) > 0) {
starterConfig.SetTargetUID(uid)
starterConfig.SetTargetGID(gids)
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
useTargetIDs = true
}
if e.EngineConfig.GetInstanceJoin() {
if err := e.prepareInstanceJoinConfig(starterConfig); err != nil {
return err
}
} else {
e.setUserInfo(useTargetIDs)
if err := e.prepareContainerConfig(starterConfig); err != nil {
return err
}
if err := e.loadImages(starterConfig); err != nil {
return err
}
}
starterConfig.SetMasterPropagateMount(true)
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)
}
// determine if engine need to propagate signals across processes
e.checkSignalPropagation()
// We must call this here because at this point we haven't
// spawned the master process nor the RPC server. The assumption
// is that this function runs in stage 1 and that even if it's a
// separate process, it's created in such a way that it's
// sharing its file descriptor table with the wrapper / stage 2.
//
// At this point we do not have elevated privileges. We assume
// that the user running singularity has access to /dev/fuse
// (typically it's 0666, or 0660 belonging to a group that
// allows the user to read and write to it).
sendFd, err := openDevFuse(e, starterConfig)
if err != nil {
return err
}
if sendFd {
fds, err := unix.Socketpair(unix.AF_UNIX, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0)
if err != nil {
return fmt.Errorf("failed to create socketpair to pass file descriptor: %s", err)
}
e.EngineConfig.SetUnixSocketPair(fds)
starterConfig.KeepFileDescriptor(fds[0])
starterConfig.KeepFileDescriptor(fds[1])
} else {
e.EngineConfig.SetUnixSocketPair([2]int{-1, -1})
}
// nvidia-container-cli requires additional caps in the starter bounding set.
// These are within the capability set for the starter process itself, *not* the capabilities
// that will be set on the running container process, which are defined with SetCapabilities above.
if e.EngineConfig.GetNvCCLI() {
starterConfig.SetNvCCLICaps(true)
}
return nil
}
// prepareUserCaps is responsible for checking that user's requested
// capabilities are authorized.
func (e *EngineOperations) prepareUserCaps(enforced bool) error {
commonCaps := make([]string, 0)
commonUnauthorizedCaps := make([]string, 0)
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
file, err := os.OpenFile(buildcfg.CAPABILITY_FILE, os.O_RDONLY, 0o644)
if err != nil {
return fmt.Errorf("while opening capability config file: %s", err)
}
defer file.Close()
capConfig, err := capabilities.ReadFrom(file)
if err != nil {
return fmt.Errorf("while parsing capability config data: %s", err)
}
pw, err := user.Current()
if err != nil {
return err
}
caps, ignoredCaps := capabilities.Split(e.EngineConfig.GetAddCaps())
if len(ignoredCaps) > 0 {
sylog.Warningf("won't add unknown capability: %s", strings.Join(ignoredCaps, ","))
}
caps = append(caps, e.EngineConfig.OciConfig.Process.Capabilities.Permitted...)
if enforced {
authorizedCaps, unauthorizedCaps := capConfig.CheckUserCaps(pw.Name, caps)
if len(authorizedCaps) > 0 {
sylog.Debugf("User capabilities %s added", strings.Join(authorizedCaps, ","))
commonCaps = authorizedCaps
}
if len(unauthorizedCaps) > 0 {
commonUnauthorizedCaps = append(commonUnauthorizedCaps, unauthorizedCaps...)
}
groups, err := os.Getgroups()
if err != nil {
return err
}
for _, g := range groups {
gr, err := user.GetGrGID(uint32(g))
if err != nil {
sylog.Debugf("Ignoring group %d: %s", g, err)
continue
}
authorizedCaps, unauthorizedCaps := capConfig.CheckGroupCaps(gr.Name, caps)
if len(authorizedCaps) > 0 {
sylog.Debugf("%s group capabilities %s added", gr.Name, strings.Join(authorizedCaps, ","))
commonCaps = append(commonCaps, authorizedCaps...)
}
if len(unauthorizedCaps) > 0 {
commonUnauthorizedCaps = append(commonUnauthorizedCaps, unauthorizedCaps...)
}
}
} else {
commonCaps = caps
}
commonCaps = capabilities.RemoveDuplicated(commonCaps)
commonUnauthorizedCaps = capabilities.RemoveDuplicated(commonUnauthorizedCaps)
// remove authorized capabilities from unauthorized capabilities list
// to end with the really unauthorized capabilities
for _, c := range commonCaps {
for i := len(commonUnauthorizedCaps) - 1; i >= 0; i-- {
if commonUnauthorizedCaps[i] == c {
commonUnauthorizedCaps = append(commonUnauthorizedCaps[:i], commonUnauthorizedCaps[i+1:]...)
break
}
}
}
if len(commonUnauthorizedCaps) > 0 {
sylog.Warningf("not authorized to add capability: %s", strings.Join(commonUnauthorizedCaps, ","))
}
caps, ignoredCaps = capabilities.Split(e.EngineConfig.GetDropCaps())
if len(ignoredCaps) > 0 {
sylog.Warningf("won't drop unknown capability: %s", strings.Join(ignoredCaps, ","))
}
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 := os.OpenFile(buildcfg.CAPABILITY_FILE, os.O_RDONLY, 0o644)
if err != nil {
return fmt.Errorf("while opening capability config file: %s", err)
}
defer file.Close()
capConfig, err := capabilities.ReadFrom(file)
if err != nil {
return fmt.Errorf("while parsing capability config data: %s", err)
}
commonCaps = append(commonCaps, capConfig.ListUserCaps("root")...)
groups, err := os.Getgroups()
if err != nil {
return fmt.Errorf("while getting groups: %s", err)
}
for _, g := range groups {
gr, err := user.GetGrGID(uint32(g))
if err != nil {
sylog.Debugf("Ignoring group %d: %s", g, err)
continue
}
caps := capConfig.ListGroupCaps(gr.Name)
commonCaps = append(commonCaps, caps...)
sylog.Debugf("%s group capabilities %s added", gr.Name, strings.Join(caps, ","))
}
default:
e.EngineConfig.OciConfig.SetProcessNoNewPrivileges(true)
}
caps, ignoredCaps := capabilities.Split(e.EngineConfig.GetAddCaps())
if len(ignoredCaps) > 0 {
sylog.Warningf("won't add unknown capability: %s", strings.Join(ignoredCaps, ","))
}
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, ignoredCaps = capabilities.Split(e.EngineConfig.GetDropCaps())
if len(ignoredCaps) > 0 {
sylog.Warningf("won't add unknown capability: %s", strings.Join(ignoredCaps, ","))
}
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 keepAutofsMount(source string, autoFsPoints []string) (int, error) {
resolved, err := filepath.EvalSymlinks(source)
if err != nil {
return -1, err
}
for _, p := range autoFsPoints {
if strings.HasPrefix(resolved, p) {
sylog.Debugf("Open file descriptor for %s", resolved)
f, err := os.Open(resolved)
if err != nil {
return -1, err
}
return int(f.Fd()), nil
}
}
return -1, fmt.Errorf("no mount point")
}
func (e *EngineOperations) prepareAutofs(starterConfig *starter.Config) error {
const mountInfoPath = "/proc/self/mountinfo"
entries, err := proc.GetMountInfoEntry(mountInfoPath)
if err != nil {
return fmt.Errorf("while parsing %s: %s", mountInfoPath, err)
}
autoFsPoints := make([]string, 0)
for _, e := range entries {
if e.FSType == "autofs" {
sylog.Debugf("Found %q as autofs mount point", e.Point)
autoFsPoints = append(autoFsPoints, e.Point)
}
}
if len(autoFsPoints) == 0 {
sylog.Debugf("No autofs mount point found")
return nil
}
fds := make([]int, 0)
if e.EngineConfig.File.UserBindControl {
for _, b := range e.EngineConfig.GetBindPath() {
fd, err := keepAutofsMount(b.Source, autoFsPoints)
if err != nil {
sylog.Debugf("Could not keep file descriptor for user bind path %s: %s", b.Source, err)
continue
}
fds = append(fds, fd)
}
}
if !e.EngineConfig.GetContain() {
for _, bindpath := range e.EngineConfig.File.BindPath {
splitted := strings.Split(bindpath, ":")
fd, err := keepAutofsMount(splitted[0], autoFsPoints)
if err != nil {
sylog.Debugf("Could not keep file descriptor for bind path %s: %s", splitted[0], err)
continue
}
fds = append(fds, fd)
}
// check home source directory
dir := e.EngineConfig.GetHomeSource()
fd, err := keepAutofsMount(dir, autoFsPoints)
if err != nil {
sylog.Debugf("Could not keep file descriptor for home directory %s: %s", dir, err)
} else {
fds = append(fds, fd)
}
// check the current working directory
dir = e.EngineConfig.GetCwd()
fd, err = keepAutofsMount(dir, autoFsPoints)
if err != nil {
sylog.Debugf("Could not keep file descriptor for current working directory %s: %s", dir, err)
} else {
fds = append(fds, fd)
}
} else {
// check workdir
dir := e.EngineConfig.GetWorkdir()
fd, err := keepAutofsMount(dir, autoFsPoints)
if err != nil {
sylog.Debugf("Could not keep file descriptor for workdir %s: %s", dir, err)
} else {
fds = append(fds, fd)
}
}
for _, f := range fds {
if err := starterConfig.KeepFileDescriptor(f); err != nil {
return err
}
}
e.EngineConfig.SetOpenFd(fds)
return nil
}
// 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 {
enforced := starterConfig.GetIsSUID()
if err := e.prepareUserCaps(enforced); err != nil {
return err
}
}
if e.EngineConfig.File.MountSlave {
starterConfig.SetMountPropagation("rslave")
} else {
starterConfig.SetMountPropagation("rprivate")
}
if e.EngineConfig.GetFakeroot() {
if !starterConfig.GetIsSUID() {
// no SUID workflow, check if newuidmap/newgidmap are present
sylog.Verbosef("Fakeroot requested with unprivileged workflow, fallback to newuidmap/newgidmap")
sylog.Debugf("Search for newuidmap binary")
if err := starterConfig.SetNewUIDMapPath(); err != nil {
return err
}
sylog.Debugf("Search for newgidmap binary")
if err := starterConfig.SetNewGIDMapPath(); err != nil {
return err
}
}
uid := uint32(os.Getuid())
gid := uint32(os.Getgid())
getIDRange := fakerootutil.GetIDRange
callbackType := (fakerootcallback.UserMapping)(nil)
callbacks, err := plugin.LoadCallbacks(callbackType)
if err != nil {
return fmt.Errorf("while loading plugins callbacks '%T': %s", callbackType, err)
}
if len(callbacks) > 1 {
return fmt.Errorf("multiple plugins have registered hook callback for fakeroot")
} else if len(callbacks) == 1 {
//nolint:forcetypeassert
getIDRange = callbacks[0].(fakerootcallback.UserMapping)
}
e.EngineConfig.OciConfig.AddLinuxUIDMapping(uid, 0, 1)
idRange, err := getIDRange(fakerootutil.SubUIDFile, uid)
if err != nil {
return fmt.Errorf("could not use fakeroot: %s", err)
}
e.EngineConfig.OciConfig.AddLinuxUIDMapping(idRange.HostID, idRange.ContainerID, idRange.Size)
starterConfig.AddUIDMappings(e.EngineConfig.OciConfig.Linux.UIDMappings)
e.EngineConfig.OciConfig.AddLinuxGIDMapping(gid, 0, 1)
idRange, err = getIDRange(fakerootutil.SubGIDFile, uid)
if err != nil {
return fmt.Errorf("could not use fakeroot: %s", err)
}
e.EngineConfig.OciConfig.AddLinuxGIDMapping(idRange.HostID, idRange.ContainerID, idRange.Size)
starterConfig.AddGIDMappings(e.EngineConfig.OciConfig.Linux.GIDMappings)
e.EngineConfig.OciConfig.SetupPrivileged(true)
e.EngineConfig.OciConfig.AddOrReplaceLinuxNamespace(specs.UserNamespace, "")
starterConfig.SetHybridWorkflow(true)
starterConfig.SetAllowSetgroups(true)
starterConfig.SetNoSetgroups(e.EngineConfig.GetNoSetgroups())
starterConfig.SetTargetUID(0)
starterConfig.SetTargetGID([]int{0})
}
starterConfig.SetBringLoopbackInterface(true)
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)
return e.prepareAutofs(starterConfig)
}
// prepareInstanceJoinConfig is responsible for getting and
// applying configuration to join a running instance.
//
//nolint:maintidx
func (e *EngineOperations) prepareInstanceJoinConfig(starterConfig *starter.Config) error {
name := instance.ExtractName(e.EngineConfig.GetImage())
file, err := instance.Get(name, instance.SingSubDir)
if err != nil {
return err
}
uid := os.Getuid()
gid := os.Getgid()
suidRequired := uid != 0 && !file.UserNs
// basic checks:
// 1. a user must not use SUID workflow to join an instance
// started with user namespace
// 2. a user must use SUID workflow to join an instance
// started without user namespace
if starterConfig.GetIsSUID() && !suidRequired {
return fmt.Errorf("joining user namespace with suid workflow is not allowed")
} else if !starterConfig.GetIsSUID() && suidRequired {
return fmt.Errorf("a setuid installation is required to join this instance")
}
// Pid and PPid are stored in instance file and can be controlled
// by users, check to make sure these values are sane
if file.Pid <= 1 || file.PPid <= 1 {
return fmt.Errorf("bad instance process ID found")
}
// instance configuration holding configuration read
// from instance file
instanceEngineConfig := singularityConfig.NewConfig()
// extract engine configuration from instance file, the whole content
// of this file can't be trusted
instanceConfig := &config.Common{
EngineConfig: instanceEngineConfig,
}
if err := json.Unmarshal(file.Config, instanceConfig); err != nil {
return err
}
// configuration may be altered, be sure to not panic
if instanceEngineConfig.OciConfig.Linux == nil {
instanceEngineConfig.OciConfig.Linux = &specs.Linux{}
}
// go into /proc/<pid> directory to open namespaces inodes
// relative to current working directory while joining
// namespaces within C starter code as changing directory
// here will also affects starter process thanks to
// SetWorkingDirectoryFd call.
// Additionally it would prevent TOCTOU races and symlink
// usage.
// And if instance process exits during checks or while
// entering in namespace, we would get a "no such process"
// error because current working directory would point to a
// deleted inode: "/proc/self/cwd -> /proc/<pid> (deleted)"
path := filepath.Join("/proc", strconv.Itoa(file.Pid))
fd, err := syscall.Open(path, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
if err != nil {
return fmt.Errorf("could not open proc directory %s: %s", path, err)
}
if err := mainthread.Fchdir(fd); err != nil {
return err
}
// will set starter (via fchdir too) in the same proc directory
// in order to open namespace inodes with relative paths for the
// right process
starterConfig.SetWorkingDirectoryFd(fd)
// If our image is FUSE mounted, we need the fd to close on cleanup
starterConfig.SetImageFd(fd)
// enforce checks while joining an instance process with SUID workflow
// since instance file is stored in user home directory, we can't trust
// its content when using SUID workflow
if suidRequired {
// check if instance is running with user namespace enabled
// by reading /proc/pid/uid_map
_, hid, err := proc.ReadIDMap("uid_map")
// if the error returned is "no such file or directory" it means
// that user namespaces are not supported, just skip this check
if err != nil && !os.IsNotExist(err) {
return fmt.Errorf("failed to read user namespace mapping: %s", err)
} else if err == nil && hid > 0 {
// a host uid greater than 0 means user namespace is in use for this process
return fmt.Errorf("trying to join an instance running with user namespace enabled")
}
// read "/proc/pid/root" link of instance process must return
// a permission denied error.
// This is the "sinit" process (PID 1 in container) and it inherited
// setuid bit, so most of "/proc/pid" entries are owned by root:root
// like "/proc/pid/root" link even if the process has dropped all
// privileges and run with user UID/GID. So we expect a "permission denied"
// error when reading link.
if _, err := mainthread.Readlink("root"); !os.IsPermission(err) {
return fmt.Errorf("trying to join a wrong instance process")
}
// Since we could be tricked to join namespaces of a root owned process,
// we will get UID/GID information of task directory to be sure it belongs
// to the user currently joining the instance. Also ensure that a user won't
// be able to join other user's instances.
fi, err := os.Stat("task")
if err != nil {
return fmt.Errorf("error while getting information for instance task directory: %s", err)
}
//nolint:forcetypeassert
st := fi.Sys().(*syscall.Stat_t)
if st.Uid != uint32(uid) || st.Gid != uint32(gid) {
return fmt.Errorf("instance process owned by %d:%d instead of %d:%d", st.Uid, st.Gid, uid, gid)
}
ppid := -1
// read "/proc/pid/status" to check if instance process
// is neither orphaned or faked
f, err := os.Open("status")
if err != nil {
return fmt.Errorf("could not open status: %s", err)
}
for s := bufio.NewScanner(f); s.Scan(); {
if n, _ := fmt.Sscanf(s.Text(), "PPid:\t%d", &ppid); n == 1 {
break
}
}
f.Close()
// check that Ppid/Pid read from instance file are "somewhat" valid
// processes
if ppid <= 1 || ppid != file.PPid {
return fmt.Errorf("orphaned (or faked) instance process")
}
// read "/proc/ppid/root" link of parent instance process must return
// a permission denied error (same logic than "sinit" process).
// Also we don't use absolute path because we want to return an error
// if current working directory is deleted meaning that instance process
// exited.
path := filepath.Join("..", strconv.Itoa(file.PPid), "root")
if _, err := mainthread.Readlink(path); !os.IsPermission(err) {
return fmt.Errorf("trying to join a wrong instance process")
}
// "/proc/ppid/task" directory must be owned by user UID/GID
path = filepath.Join("..", strconv.Itoa(file.PPid), "task")
fi, err = os.Stat(path)
if err != nil {
return fmt.Errorf("error while getting information for parent task directory: %s", err)
}
//nolint:forcetypeassert
st = fi.Sys().(*syscall.Stat_t)
if st.Uid != uint32(uid) || st.Gid != uint32(gid) {
return fmt.Errorf("parent instance process owned by %d:%d instead of %d:%d", st.Uid, st.Gid, uid, gid)
}
path, err = filepath.Abs("comm")
if err != nil {
return fmt.Errorf("failed to determine absolute path for comm: %s", err)
}
// we must read "sinit\n"
b, err := os.ReadFile("comm")
if err != nil {
return fmt.Errorf("failed to read %s: %s", path, err)
}
// check that we are currently joining sinit process
if "sinit" != strings.Trim(string(b), "\n") {
return fmt.Errorf("sinit not found in %s, wrong instance process", path)
}
}
// tell starter that we are joining an instance
starterConfig.SetNamespaceJoinOnly(true)
// update namespaces path relative to /proc/<pid>
// since starter process is in /proc/<pid> directory
for i := range instanceEngineConfig.OciConfig.Linux.Namespaces {
// ignore unknown namespaces
t := instanceEngineConfig.OciConfig.Linux.Namespaces[i].Type
if _, ok := nsProcName[t]; !ok {
continue
}
// set namespace relative path
instanceEngineConfig.OciConfig.Linux.Namespaces[i].Path = filepath.Join("ns", nsProcName[t])
}
// store namespace paths in starter configuration that will
// be passed via a shared memory area and used by starter C code
// once this process exit
if err := starterConfig.SetNsPathFromSpec(instanceEngineConfig.OciConfig.Linux.Namespaces); err != nil {
return err
}
// 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
}
// check if user is authorized to set those capabilities and remove
// unauthorized capabilities from current set according to capability
// configuration file
if uid == 0 {
if err := e.prepareRootCaps(); err != nil {
return err
}
} else {
if err := e.prepareUserCaps(suidRequired); err != nil {
return err
}
}
// set UID/GID for the fakeroot context
if instanceEngineConfig.GetFakeroot() {
starterConfig.SetTargetUID(0)
starterConfig.SetTargetGID([]int{0})
}
// restore HOME environment variable to match the
// one set during instance start
e.EngineConfig.OciConfig.AddProcessEnv("HOME", instanceEngineConfig.GetHomeDest())
// restore apparmor profile or apply a new one if provided
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 or apply a new one if provided
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 seccomp filter or apply a new one if provided
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 e.EngineConfig.OciConfig.Linux == nil {
e.EngineConfig.OciConfig.Linux = &specs.Linux{}
}
e.EngineConfig.OciConfig.Linux.Seccomp = instanceEngineConfig.OciConfig.Linux.Seccomp
}
// Note - in non-root flow without userns the CLI process joined the cgroup
// early in execStarter because we don't have permission to move a parent
// process into the cgroup here. In that case, this code is a no-op that
// just enforces that actually happened.
if file.Cgroup {
sylog.Debugf("Adding process to instance cgroup")
ppid := os.Getppid()
manager, err := cgroups.GetManagerForPid(file.Pid)
if err != nil {
return fmt.Errorf("couldn't create cgroup manager: %v", err)
}
if err := manager.AddProc(ppid); err != nil {
return fmt.Errorf("couldn't add process to instance cgroup: %v", err)
}
}
// only root user can set this value based on instance file
// and always set to true for normal users or if instance file
// returned a wrong configuration
if uid == 0 && instanceEngineConfig.OciConfig.Process != nil {
e.EngineConfig.OciConfig.Process.NoNewPrivileges = instanceEngineConfig.OciConfig.Process.NoNewPrivileges
} else {
e.EngineConfig.OciConfig.Process.NoNewPrivileges = true
}
return nil
}
// openDevFuse is a helper function that opens /dev/fuse once for each
// plugin that wants to mount a FUSE filesystem.
func openDevFuse(e *EngineOperations, starterConfig *starter.Config) (bool, error) {
// do we require to send file descriptor
sendFd := false
// we won't copy slice while iterating fuse mounts
mounts := e.EngineConfig.GetFuseMount()
if len(mounts) == 0 {
return false, nil
}
if !e.EngineConfig.File.EnableFusemount {
return false, fmt.Errorf("fusemount disabled by configuration 'enable fusemount = no'")
}
for i := range mounts {
sylog.Debugf("Opening /dev/fuse for FUSE mount point %s\n", mounts[i].MountPoint)
fd, err := syscall.Open("/dev/fuse", syscall.O_RDWR, 0)
if err != nil {
return false, err
}
mounts[i].Fd = fd
starterConfig.KeepFileDescriptor(fd)
if (!starterConfig.GetIsSUID() || e.EngineConfig.GetFakeroot()) && !mounts[i].FromContainer {
sendFd = true
}
}
return sendFd, nil
}
func (e *EngineOperations) checkSignalPropagation() {
// obtain the process group ID of the associated controlling
// terminal (if there's one).
pgrp := 0
for i := 0; i <= 2; i++ {
// The two possible errors:
// - EBADF will return 0 as process group
// - ENOTTY will also return 0 as process group
pgrp, _ = unix.IoctlGetInt(i, unix.TIOCGPGRP)
// based on kernel source a 0 value for process group
// theoretically be set but really not sure it can happen
// with linux tty behavior
if pgrp != 0 {
break
}
}
// cases we need to propagate signals to container process:
// - when pgrp == 0 because container won't run in a terminal
// - when process group is different from the process group controlling terminal
if pgrp == 0 || (pgrp > 0 && pgrp != syscall.Getpgrp()) {
e.EngineConfig.SetSignalPropagation(true)
}
}
// setSessionLayer will test if overlay is supported/allowed.
func (e *EngineOperations) setSessionLayer(img *image.Image) error {
e.EngineConfig.SetSessionLayer(singularityConfig.DefaultLayer)
writableTmpfs := e.EngineConfig.GetWritableTmpfs()
writableImage := e.EngineConfig.GetWritableImage()
hasOverlayImage := len(e.EngineConfig.GetOverlayImage()) > 0
if writableImage && hasOverlayImage {
return fmt.Errorf("you could not use --overlay in conjunction with --writable")
}
// a SIF image may contain one or more overlay partition
// check there is at least one ext3 overlay partition
// to validate overlay with writable flag
hasSIFOverlay := false
if img.Type == image.SIF {
overlays, err := img.GetOverlayPartitions()
if err != nil {
return fmt.Errorf("while getting overlay partition in SIF image %s: %s", img.Path, err)
}
for _, o := range overlays {
if o.Type == image.EXT3 {
hasSIFOverlay = true
break
}
}
}
// Check for implicit user namespace, e.g when we run %test in a fakeroot build
// https://github.com/hpcng/singularity/issues/5315
userNS, _ := namespaces.IsInsideUserNamespace(os.Getpid())
// Check for explicit user namespace request
if !userNS {
for _, ns := range e.EngineConfig.OciConfig.Linux.Namespaces {
if ns.Type == specs.UserNamespace {
userNS = true
break
}
}
}
// Check for kernel rootless overlay support if userNS in effect
rootlessOverlay := false
useOverlay := e.EngineConfig.File.EnableOverlay == "yes" || e.EngineConfig.File.EnableOverlay == "try"
if userNS && useOverlay {
err := overlay.CheckRootless()
if err == nil {
rootlessOverlay = true
}
if err != nil && err != overlay.ErrNoRootlessOverlay {
sylog.Warningf("While checking for rootless overlay support: %s", err)
}
}
// If rootless overlay is not supported for userns, we can only try underlay.
if userNS && !rootlessOverlay {
if !e.EngineConfig.File.EnableUnderlay {
sylog.Debugf("Not attempting to use underlay with user namespace: disabled by configuration ('enable underlay = no')")
return nil
}
if !writableImage {
sylog.Debugf("Using underlay layer: user namespace requested")
e.EngineConfig.SetSessionLayer(singularityConfig.UnderlayLayer)
return nil
}
sylog.Debugf("Not attempting to use overlay or underlay: writable flag requested")
return nil
}
// Now check if there is an overlay entry in /proc/filesystems
// Setuid starter will force module load.
// Rootless overlay mount check will also force module load.
if has, _ := proc.HasFilesystem("overlay"); has {
sylog.Debugf("Overlay seems supported and allowed by kernel")
switch e.EngineConfig.File.EnableOverlay {
case "yes", "try":
e.EngineConfig.SetSessionLayer(singularityConfig.OverlayLayer)
if !writableImage || hasSIFOverlay {
sylog.Debugf("Attempting to use overlayfs (enable overlay = %v)\n", e.EngineConfig.File.EnableOverlay)
return nil
}
sylog.Debugf("Not attempting to use overlay or underlay: writable flag requested")
e.EngineConfig.SetSessionLayer(singularityConfig.DefaultLayer)
return nil
default:
if hasOverlayImage {
return fmt.Errorf("overlay images requires 'enable overlay = yes': set to 'no' by administrator")
}
if writableTmpfs {
return fmt.Errorf("--writable-tmpfs requires 'enable overlay = yes': set to 'no' by administrator")
}
sylog.Debugf("Could not use overlay, disabled by configuration ('enable overlay = no')")
}
} else {
if writableTmpfs {
return fmt.Errorf("--writable-tmpfs requires overlay kernel support: your kernel doesn't support it")
}
if hasOverlayImage {
return fmt.Errorf("overlay images requires overlay kernel support: your kernel doesn't support it")
}
}
// if --writable wasn't set, use underlay if possible
if !writableImage && e.EngineConfig.File.EnableUnderlay {
sylog.Debugf("Attempting to use underlay (enable underlay = yes)\n")
e.EngineConfig.SetSessionLayer(singularityConfig.UnderlayLayer)
return nil
} else if writableImage {
sylog.Debugf("Not attempting to use overlay or underlay: writable flag requested")
return nil
}
sylog.Debugf("Not attempting to use overlay or underlay: both disabled by administrator")
return nil
}
func (e *EngineOperations) loadImages(starterConfig *starter.Config) 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
}
rootFs, err := img.GetRootFsPartition()
if err != nil {
return fmt.Errorf("while getting root filesystem partition in %s: %s", e.EngineConfig.GetImage(), err)
}
if writable && !img.Writable {
return fmt.Errorf("could not use %s for writing, you don't have write permissions", img.Path)
}
if err := e.setSessionLayer(img); err != nil {
return err
}
// first image is always the root filesystem
images = append(images, *img)
writableOverlayPath := ""
if err := starterConfig.KeepFileDescriptor(int(img.Fd)); err != nil {
return err
}
// sandbox are handled differently for security reasons
if img.Type == image.SANDBOX {
if img.Path == "/" {
return fmt.Errorf("/ as sandbox is not authorized")
}
// C starter code will position current working directory
starterConfig.SetWorkingDirectoryFd(int(img.Fd))
// If our image is FUSE mounted, we need the fd to close on cleanup
starterConfig.SetImageFd(int(img.Fd))
if e.EngineConfig.GetSessionLayer() == singularityConfig.OverlayLayer {
if err := overlay.CheckLower(img.Path); overlay.IsIncompatible(err) {
layer := singularityConfig.UnderlayLayer
if !e.EngineConfig.File.EnableUnderlay {
sylog.Warningf("Could not fallback to underlay, disabled by configuration ('enable underlay = no')")
layer = singularityConfig.DefaultLayer
}
e.EngineConfig.SetSessionLayer(layer)
// show a warning message if --writable-tmpfs or overlay images
// are requested otherwise make it verbose to not annoy users
if e.EngineConfig.GetWritableTmpfs() || len(e.EngineConfig.GetOverlayImage()) > 0 {
sylog.Warningf("Fallback to %s layer: %s", layer, err)
if e.EngineConfig.GetWritableTmpfs() {
e.EngineConfig.SetWritableTmpfs(false)
sylog.Warningf("--writable-tmpfs disabled due to sandbox filesystem incompatibility with overlay")
}
if len(e.EngineConfig.GetOverlayImage()) > 0 {
e.EngineConfig.SetOverlayImage(nil)
sylog.Warningf("overlay image(s) not loaded due to sandbox filesystem incompatibility with overlay")
}
} else {
sylog.Verbosef("Fallback to %s layer: %s", layer, err)
}
} else if err != nil {
return fmt.Errorf("while checking image compatibility with overlay: %s", err)
}
}
} else 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 fmt.Errorf("while validating ECL configuration: %s", err)
}
// Only try to load the global keyring here if the ECL is active.
// Otherwise pass through an empty keyring rather than avoiding calling
// the ECL functions as this keeps the logic for applying / ignoring ECL in a
// single location.
var kr openpgp.KeyRing = openpgp.EntityList{}
if ecl.Activated {
keyring := sypgp.NewHandle(buildcfg.SINGULARITY_CONFDIR, sypgp.GlobalHandleOpt())
kr, err = keyring.LoadPubKeyring()
if err != nil {
return fmt.Errorf("while obtaining keyring for ECL: %s", err)
}
}
if ok, err := ecl.ShouldRunFp(context.TODO(), img.File, kr); err != nil {
return fmt.Errorf("while checking container image with ECL: %s", err)
} else if !ok {
return errors.New("image prohibited by ECL")
}
}
// look for potential overlay partition in SIF image
if e.EngineConfig.GetSessionLayer() == singularityConfig.OverlayLayer {
overlays, err := img.GetOverlayPartitions()
if err != nil {
return fmt.Errorf("while getting overlay partitions in %s: %s", img.Path, err)
}
for _, p := range overlays {
if img.Writable && p.Type == image.EXT3 {
writableOverlayPath = img.Path
}
}
}
// SIF image open for writing without writable
// overlay partition, assuming that the root
// filesystem is squashfs or encrypted squashfs
if img.Writable && rootFs.Type != image.EXT3 && writableOverlayPath == "" {
return fmt.Errorf("no SIF writable overlay partition found in %s", img.Path)
}
}
switch e.EngineConfig.GetSessionLayer() {
case singularityConfig.OverlayLayer:
overlayImages, err := e.loadOverlayImages(starterConfig, writableOverlayPath)
if err != nil {
return fmt.Errorf("while loading overlay images: %s", err)
}
images = append(images, overlayImages...)
case singularityConfig.UnderlayLayer:
if e.EngineConfig.GetWritableTmpfs() {
sylog.Warningf("Disabling --writable-tmpfs as it can't be used in conjunction with underlay")
e.EngineConfig.SetWritableTmpfs(false)
}
}
bindImages, err := e.loadBindImages(starterConfig)
if err != nil {
return fmt.Errorf("while loading data bind images: %s", err)
}
images = append(images, bindImages...)
e.EngineConfig.SetImageList(images)
return nil
}
// loadOverlayImages loads overlay images.
func (e *EngineOperations) loadOverlayImages(starterConfig *starter.Config, writableOverlayPath string) ([]image.Image, error) {
images := make([]image.Image, 0)
for _, overlayImg := range e.EngineConfig.GetOverlayImage() {
writableOverlay := true
splitted := strings.SplitN(overlayImg, ":", 2)
if len(splitted) == 2 {
if splitted[1] == "ro" {
writableOverlay = false
}
}
img, err := e.loadImage(splitted[0], writableOverlay)
if err != nil {
if !image.IsReadOnlyFilesytem(err) {
return nil, fmt.Errorf("failed to open overlay image %s: %s", splitted[0], err)
}
// let's proceed with readonly filesystem and set
// writableOverlay to appropriate value
writableOverlay = false
}
img.Usage = image.OverlayUsage
if writableOverlay && img.Writable {
if writableOverlayPath != "" {
return nil, fmt.Errorf(
"you can't specify more than one writable overlay, "+
"%s contains a writable overlay, requires to use '--overlay %s:ro'",
writableOverlayPath, img.Path,
)
}
writableOverlayPath = img.Path
}
if err := starterConfig.KeepFileDescriptor(int(img.Fd)); err != nil {
return nil, err
}
images = append(images, *img)
}
if e.EngineConfig.GetWritableTmpfs() && writableOverlayPath != "" {
return nil, fmt.Errorf("you can't specify --writable-tmpfs with another writable overlay image (%s)", writableOverlayPath)
}
return images, nil
}
// loadBindImages load data bind images.
func (e *EngineOperations) loadBindImages(starterConfig *starter.Config) ([]image.Image, error) {
images := make([]image.Image, 0)
binds := e.EngineConfig.GetBindPath()
for i := range binds {
if binds[i].ImageSrc() == "" && binds[i].ID() == "" {
continue
}
imagePath := binds[i].Source
sylog.Debugf("Loading data image %s", imagePath)
img, err := e.loadImage(imagePath, !binds[i].Readonly())
if err != nil && !image.IsReadOnlyFilesytem(err) {
return nil, fmt.Errorf("failed to load data image %s: %s", imagePath, err)
}
img.Usage = image.DataUsage
if err := starterConfig.KeepFileDescriptor(int(img.Fd)); err != nil {
return nil, err
}
images = append(images, *img)
binds[i].Source = img.Source
}
return images, nil
}
func (e *EngineOperations) loadImage(path string, writable bool) (*image.Image, error) {
const delSuffix = " (deleted)"
imgObject, imgErr := image.Init(path, writable)
// pass imgObject if not nil for overlay and read-only filesystem error.
// Do not remove this line
if imgErr != nil && imgObject == nil {
return nil, imgErr
}
// get the real path from /proc/self/fd/X
imgTarget, err := mainthread.Readlink(imgObject.Source)
if err != nil {
return nil, fmt.Errorf("while reading symlink %s: %s", imgObject.Source, err)
}
// imgObject.Path is the resolved path provided to image.Init and imgTarget point
// to the opened path, if they are not identical (for some obscure reasons) we use
// the resolved path from /proc/self/fd/X
if imgObject.Path != imgTarget {
// With some kernel/filesystem combination the symlink target of /proc/self/fd/X
// may return a path with the suffix " (deleted)" even if not deleted, we just
// remove it because it won't impact ACL path check
finalTarget := strings.TrimSuffix(imgTarget, delSuffix)
sylog.Debugf("Replacing image resolved path %s by %s", imgObject.Path, finalTarget)
imgObject.Path = finalTarget
}
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 {
// Bare SquashFS
case image.SQUASHFS:
if !e.EngineConfig.File.AllowContainerSquashfs {
return nil, fmt.Errorf("configuration disallows users from running squashFS containers")
}
// Bare EXT3
case image.EXT3:
if !e.EngineConfig.File.AllowContainerExtfs {
return nil, fmt.Errorf("configuration disallows users from running extFS containers")
}
// Bare sandbox directory
case image.SANDBOX:
if !e.EngineConfig.File.AllowContainerDir {
return nil, fmt.Errorf("configuration disallows users from running sandbox containers")
}
// SIF
case image.SIF:
// Check if SIF contains an encrypted rootfs partition.
// We don't support encryption for other partitions at present.
encrypted, err := imgObject.HasEncryptedRootFs()
if err != nil {
return nil, fmt.Errorf("while checking for encrypted root FS: %v", err)
}
// SIF with encryption
if encrypted && !e.EngineConfig.File.AllowContainerEncrypted {
return nil, fmt.Errorf("configuration disallows users from running encrypted SIF containers")
}
// SIF without encryption - regardless of rootfs filesystem type
if !encrypted && !e.EngineConfig.File.AllowContainerSIF {
return nil, fmt.Errorf("configuration disallows users from running unencrypted SIF containers")
}
// We shouldn't be able to run anything else, but make sure we don't!
default:
return nil, fmt.Errorf("unknown image format %d", imgObject.Type)
}
return imgObject, imgErr
}
func (e *EngineOperations) setUserInfo(useTargetIDs bool) {
var gids []int
pw, err := user.CurrentOriginal()
if err != nil {
return
}
e.EngineConfig.JSON.UserInfo.Home = pw.Dir
if useTargetIDs {
pw, err = user.GetPwUID(uint32(e.EngineConfig.GetTargetUID()))
if err == nil {
e.EngineConfig.JSON.UserInfo.Username = pw.Name
e.EngineConfig.JSON.UserInfo.Gecos = pw.Gecos
e.EngineConfig.JSON.UserInfo.UID = int(pw.UID)
e.EngineConfig.JSON.UserInfo.GID = int(pw.GID)
}
} else {
e.EngineConfig.JSON.UserInfo.Username = pw.Name
e.EngineConfig.JSON.UserInfo.Gecos = pw.Gecos
e.EngineConfig.JSON.UserInfo.UID = int(pw.UID)
e.EngineConfig.JSON.UserInfo.GID = int(pw.GID)
}
e.EngineConfig.JSON.UserInfo.Groups = make(map[int]string)
if useTargetIDs {
gids = e.EngineConfig.GetTargetGID()
} else {
gids, err = os.Getgroups()
if err != nil {
return
}
}
if pw != nil {
gids = append(gids, int(pw.GID))
}
for _, gid := range gids {
group, err := user.GetGrGID(uint32(gid))
if err == nil {
e.EngineConfig.JSON.UserInfo.Groups[gid] = group.Name
}
}
}
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