From b5c99c0e95c331647e9c4352ac6adae862c05b2e Mon Sep 17 00:00:00 2001
From: Derek McGowan <derek@mcg.dev>
Date: Sat, 1 Mar 2025 00:11:49 -0800
Subject: [PATCH 1/3] Update moby/sys/user to version which includes mapping

Update idtools to use Mkdir funcs from moby sys/user package
Add deprecation exception to golanci until move off idtools is complete

Signed-off-by: Derek McGowan <derek@mcg.dev>
---
 .golangci.yml                                 |   4 +
 pkg/idtools/idtools.go                        |  28 +++-
 pkg/idtools/idtools_unix_test.go              |  18 +--
 pkg/idtools/idtools_windows.go                |  12 --
 vendor.mod                                    |   2 +-
 vendor.sum                                    |   4 +-
 vendor/github.com/moby/sys/user/idtools.go    | 141 ++++++++++++++++++
 .../github.com/moby/sys/user}/idtools_unix.go |  63 +++-----
 .../moby/sys/user/idtools_windows.go          |  13 ++
 vendor/modules.txt                            |   2 +-
 10 files changed, 208 insertions(+), 79 deletions(-)
 create mode 100644 vendor/github.com/moby/sys/user/idtools.go
 rename {pkg/idtools => vendor/github.com/moby/sys/user}/idtools_unix.go (62%)
 create mode 100644 vendor/github.com/moby/sys/user/idtools_windows.go

diff --git a/.golangci.yml b/.golangci.yml
index ae92a4fdf3..bda9aad4fb 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -212,6 +212,10 @@ issues:
       linters:
         - staticcheck
 
+    - text: "SA1019: idtools\\.(CurrentIdentity|FromUserIdentityMapping|IDMap|MkdirAndChown|MkdirAllAndChown|MkdirAllAndChownNew) is deprecated"
+      linters:
+        - staticcheck
+
     # Ignore "nested context in function literal (fatcontext)" as we intentionally set up tracing on a base-context for tests.
     # FIXME(thaJeztah): see if there's a more iodiomatic way to do this.
     - text: 'nested context in function literal'
diff --git a/pkg/idtools/idtools.go b/pkg/idtools/idtools.go
index d2fbd943a6..37b184cc62 100644
--- a/pkg/idtools/idtools.go
+++ b/pkg/idtools/idtools.go
@@ -3,11 +3,15 @@ package idtools
 import (
 	"fmt"
 	"os"
+
+	"github.com/moby/sys/user"
 )
 
 // IDMap contains a single entry for user namespace range remapping. An array
 // of IDMap entries represents the structure that will be provided to the Linux
 // kernel for creating a user namespace.
+//
+// Deprecated: use [user.IDMap] instead.
 type IDMap struct {
 	ContainerID int `json:"container_id"`
 	HostID      int `json:"host_id"`
@@ -17,28 +21,42 @@ type IDMap struct {
 // MkdirAllAndChown creates a directory (include any along the path) and then modifies
 // ownership to the requested uid/gid.  If the directory already exists, this
 // function will still change ownership and permissions.
+//
+// Deprecated: use [user.MkdirAllAndChown] instead.
 func MkdirAllAndChown(path string, mode os.FileMode, owner Identity) error {
-	return mkdirAs(path, mode, owner, true, true)
+	return user.MkdirAllAndChown(path, mode, owner.UID, owner.GID)
 }
 
 // MkdirAndChown creates a directory and then modifies ownership to the requested uid/gid.
 // If the directory already exists, this function still changes ownership and permissions.
 // Note that unlike os.Mkdir(), this function does not return IsExist error
 // in case path already exists.
+//
+// Deprecated: use [user.MkdirAndChown] instead.
 func MkdirAndChown(path string, mode os.FileMode, owner Identity) error {
-	return mkdirAs(path, mode, owner, false, true)
+	return user.MkdirAndChown(path, mode, owner.UID, owner.GID)
 }
 
 // MkdirAllAndChownNew creates a directory (include any along the path) and then modifies
 // ownership ONLY of newly created directories to the requested uid/gid. If the
 // directories along the path exist, no change of ownership or permissions will be performed
+//
+// Deprecated: use [user.MkdirAllAndChown] instead.
 func MkdirAllAndChownNew(path string, mode os.FileMode, owner Identity) error {
-	return mkdirAs(path, mode, owner, true, false)
+	return user.MkdirAllAndChown(path, mode, owner.UID, owner.GID, user.WithOnlyNew)
 }
 
 // GetRootUIDGID retrieves the remapped root uid/gid pair from the set of maps.
 // If the maps are empty, then the root uid/gid will default to "real" 0/0
+//
+// Deprecated: use [(user.IdentityMapping).RootPair] instead.
 func GetRootUIDGID(uidMap, gidMap []IDMap) (int, int, error) {
+	return getRootUIDGID(uidMap, gidMap)
+}
+
+// getRootUIDGID retrieves the remapped root uid/gid pair from the set of maps.
+// If the maps are empty, then the root uid/gid will default to "real" 0/0
+func getRootUIDGID(uidMap, gidMap []IDMap) (int, int, error) {
 	uid, err := toHost(0, uidMap)
 	if err != nil {
 		return -1, -1, err
@@ -105,7 +123,7 @@ type IdentityMapping struct {
 // because a root user always exists, and the defaults are correct when the uid
 // and gid maps are empty.
 func (i IdentityMapping) RootPair() Identity {
-	uid, gid, _ := GetRootUIDGID(i.UIDMaps, i.GIDMaps)
+	uid, gid, _ := getRootUIDGID(i.UIDMaps, i.GIDMaps)
 	return Identity{UID: uid, GID: gid}
 }
 
@@ -144,6 +162,8 @@ func (i IdentityMapping) Empty() bool {
 }
 
 // CurrentIdentity returns the identity of the current process
+//
+// Deprecated: use [os.Getuid] and [os.Getegid] instead.
 func CurrentIdentity() Identity {
 	return Identity{UID: os.Getuid(), GID: os.Getegid()}
 }
diff --git a/pkg/idtools/idtools_unix_test.go b/pkg/idtools/idtools_unix_test.go
index 381a1d7a62..916c2811e9 100644
--- a/pkg/idtools/idtools_unix_test.go
+++ b/pkg/idtools/idtools_unix_test.go
@@ -334,7 +334,7 @@ func TestGetRootUIDGID(t *testing.T) {
 		},
 	}
 
-	uid, gid, err := GetRootUIDGID(uidMap, gidMap)
+	uid, gid, err := getRootUIDGID(uidMap, gidMap)
 	assert.Check(t, err)
 	assert.Check(t, is.Equal(os.Geteuid(), uid))
 	assert.Check(t, is.Equal(os.Getegid(), gid))
@@ -346,7 +346,7 @@ func TestGetRootUIDGID(t *testing.T) {
 			Size:        1,
 		},
 	}
-	_, _, err = GetRootUIDGID(uidMapError, gidMap)
+	_, _, err = getRootUIDGID(uidMapError, gidMap)
 	assert.Check(t, is.Error(err, "Container ID 0 cannot be mapped to a host ID"))
 }
 
@@ -364,20 +364,6 @@ func TestToContainer(t *testing.T) {
 	assert.Check(t, is.Equal(uidMap[0].ContainerID, containerID))
 }
 
-// TestMkdirIsNotDir checks that mkdirAs() function (used by MkdirAll...)
-// returns a correct error in case a directory which it is about to create
-// already exists but is a file (rather than a directory).
-func TestMkdirIsNotDir(t *testing.T) {
-	file, err := os.CreateTemp("", t.Name())
-	if err != nil {
-		t.Fatalf("Couldn't create temp dir: %v", err)
-	}
-	defer os.Remove(file.Name())
-
-	err = mkdirAs(file.Name(), 0o755, Identity{UID: 0, GID: 0}, false, false)
-	assert.Check(t, is.Error(err, "mkdir "+file.Name()+": not a directory"))
-}
-
 func RequiresRoot(t *testing.T) {
 	skip.If(t, os.Getuid() != 0, "skipping test that requires root")
 }
diff --git a/pkg/idtools/idtools_windows.go b/pkg/idtools/idtools_windows.go
index a12b14040a..f83f59f30c 100644
--- a/pkg/idtools/idtools_windows.go
+++ b/pkg/idtools/idtools_windows.go
@@ -1,9 +1,5 @@
 package idtools
 
-import (
-	"os"
-)
-
 const (
 	SeTakeOwnershipPrivilege = "SeTakeOwnershipPrivilege"
 )
@@ -14,11 +10,3 @@ const (
 
 	ContainerUserSidString = "S-1-5-93-2-2"
 )
-
-// This is currently a wrapper around [os.MkdirAll] since currently
-// permissions aren't set through this path, the identity isn't utilized.
-// Ownership is handled elsewhere, but in the future could be support here
-// too.
-func mkdirAs(path string, _ os.FileMode, _ Identity, _, _ bool) error {
-	return os.MkdirAll(path, 0)
-}
diff --git a/vendor.mod b/vendor.mod
index b3391db995..a5241f6898 100644
--- a/vendor.mod
+++ b/vendor.mod
@@ -76,7 +76,7 @@ require (
 	github.com/moby/sys/sequential v0.6.0
 	github.com/moby/sys/signal v0.7.1
 	github.com/moby/sys/symlink v0.3.0
-	github.com/moby/sys/user v0.3.0
+	github.com/moby/sys/user v0.4.0
 	github.com/moby/sys/userns v0.1.0
 	github.com/moby/term v0.5.2
 	github.com/morikuni/aec v1.0.0
diff --git a/vendor.sum b/vendor.sum
index 3a957d5bb4..42a8de83c7 100644
--- a/vendor.sum
+++ b/vendor.sum
@@ -409,8 +409,8 @@ github.com/moby/sys/signal v0.7.1 h1:PrQxdvxcGijdo6UXXo/lU/TvHUWyPhj7UOpSo8tuvk0
 github.com/moby/sys/signal v0.7.1/go.mod h1:Se1VGehYokAkrSQwL4tDzHvETwUZlnY7S5XtQ50mQp8=
 github.com/moby/sys/symlink v0.3.0 h1:GZX89mEZ9u53f97npBy4Rc3vJKj7JBDj/PN2I22GrNU=
 github.com/moby/sys/symlink v0.3.0/go.mod h1:3eNdhduHmYPcgsJtZXW1W4XUJdZGBIkttZ8xKqPUJq0=
-github.com/moby/sys/user v0.3.0 h1:9ni5DlcW5an3SvRSx4MouotOygvzaXbaSrc/wGDFWPo=
-github.com/moby/sys/user v0.3.0/go.mod h1:bG+tYYYJgaMtRKgEmuueC0hJEAZWwtIbZTB+85uoHjs=
+github.com/moby/sys/user v0.4.0 h1:jhcMKit7SA80hivmFJcbB1vqmw//wU61Zdui2eQXuMs=
+github.com/moby/sys/user v0.4.0/go.mod h1:bG+tYYYJgaMtRKgEmuueC0hJEAZWwtIbZTB+85uoHjs=
 github.com/moby/sys/userns v0.1.0 h1:tVLXkFOxVu9A64/yh59slHVv9ahO9UIev4JZusOLG/g=
 github.com/moby/sys/userns v0.1.0/go.mod h1:IHUYgu/kao6N8YZlp9Cf444ySSvCmDlmzUcYfDHOl28=
 github.com/moby/term v0.5.2 h1:6qk3FJAFDs6i/q3W/pQ97SX192qKfZgGjCQqfCJkgzQ=
diff --git a/vendor/github.com/moby/sys/user/idtools.go b/vendor/github.com/moby/sys/user/idtools.go
new file mode 100644
index 0000000000..595b7a9272
--- /dev/null
+++ b/vendor/github.com/moby/sys/user/idtools.go
@@ -0,0 +1,141 @@
+package user
+
+import (
+	"fmt"
+	"os"
+)
+
+// MkdirOpt is a type for options to pass to Mkdir calls
+type MkdirOpt func(*mkdirOptions)
+
+type mkdirOptions struct {
+	onlyNew bool
+}
+
+// WithOnlyNew is an option for MkdirAllAndChown that will only change ownership and permissions
+// on newly created directories.  If the directory already exists, it will not be modified
+func WithOnlyNew(o *mkdirOptions) {
+	o.onlyNew = true
+}
+
+// MkdirAllAndChown creates a directory (include any along the path) and then modifies
+// ownership to the requested uid/gid.  By default, if the directory already exists, this
+// function will still change ownership and permissions. If WithOnlyNew is passed as an
+// option, then only the newly created directories will have ownership and permissions changed.
+func MkdirAllAndChown(path string, mode os.FileMode, uid, gid int, opts ...MkdirOpt) error {
+	var options mkdirOptions
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return mkdirAs(path, mode, uid, gid, true, options.onlyNew)
+}
+
+// MkdirAndChown creates a directory and then modifies ownership to the requested uid/gid.
+// By default, if the directory already exists, this function still changes ownership and permissions.
+// If WithOnlyNew is passed as an option, then only the newly created directory will have ownership
+// and permissions changed.
+// Note that unlike os.Mkdir(), this function does not return IsExist error
+// in case path already exists.
+func MkdirAndChown(path string, mode os.FileMode, uid, gid int, opts ...MkdirOpt) error {
+	var options mkdirOptions
+	for _, opt := range opts {
+		opt(&options)
+	}
+	return mkdirAs(path, mode, uid, gid, false, options.onlyNew)
+}
+
+// getRootUIDGID retrieves the remapped root uid/gid pair from the set of maps.
+// If the maps are empty, then the root uid/gid will default to "real" 0/0
+func getRootUIDGID(uidMap, gidMap []IDMap) (int, int, error) {
+	uid, err := toHost(0, uidMap)
+	if err != nil {
+		return -1, -1, err
+	}
+	gid, err := toHost(0, gidMap)
+	if err != nil {
+		return -1, -1, err
+	}
+	return uid, gid, nil
+}
+
+// toContainer takes an id mapping, and uses it to translate a
+// host ID to the remapped ID. If no map is provided, then the translation
+// assumes a 1-to-1 mapping and returns the passed in id
+func toContainer(hostID int, idMap []IDMap) (int, error) {
+	if idMap == nil {
+		return hostID, nil
+	}
+	for _, m := range idMap {
+		if (int64(hostID) >= m.ParentID) && (int64(hostID) <= (m.ParentID + m.Count - 1)) {
+			contID := int(m.ID + (int64(hostID) - m.ParentID))
+			return contID, nil
+		}
+	}
+	return -1, fmt.Errorf("host ID %d cannot be mapped to a container ID", hostID)
+}
+
+// toHost takes an id mapping and a remapped ID, and translates the
+// ID to the mapped host ID. If no map is provided, then the translation
+// assumes a 1-to-1 mapping and returns the passed in id #
+func toHost(contID int, idMap []IDMap) (int, error) {
+	if idMap == nil {
+		return contID, nil
+	}
+	for _, m := range idMap {
+		if (int64(contID) >= m.ID) && (int64(contID) <= (m.ID + m.Count - 1)) {
+			hostID := int(m.ParentID + (int64(contID) - m.ID))
+			return hostID, nil
+		}
+	}
+	return -1, fmt.Errorf("container ID %d cannot be mapped to a host ID", contID)
+}
+
+// IdentityMapping contains a mappings of UIDs and GIDs.
+// The zero value represents an empty mapping.
+type IdentityMapping struct {
+	UIDMaps []IDMap `json:"UIDMaps"`
+	GIDMaps []IDMap `json:"GIDMaps"`
+}
+
+// RootPair returns a uid and gid pair for the root user. The error is ignored
+// because a root user always exists, and the defaults are correct when the uid
+// and gid maps are empty.
+func (i IdentityMapping) RootPair() (int, int) {
+	uid, gid, _ := getRootUIDGID(i.UIDMaps, i.GIDMaps)
+	return uid, gid
+}
+
+// ToHost returns the host UID and GID for the container uid, gid.
+// Remapping is only performed if the ids aren't already the remapped root ids
+func (i IdentityMapping) ToHost(uid, gid int) (int, int, error) {
+	var err error
+	ruid, rgid := i.RootPair()
+
+	if uid != ruid {
+		ruid, err = toHost(uid, i.UIDMaps)
+		if err != nil {
+			return ruid, rgid, err
+		}
+	}
+
+	if gid != rgid {
+		rgid, err = toHost(gid, i.GIDMaps)
+	}
+	return ruid, rgid, err
+}
+
+// ToContainer returns the container UID and GID for the host uid and gid
+func (i IdentityMapping) ToContainer(uid, gid int) (int, int, error) {
+	ruid, err := toContainer(uid, i.UIDMaps)
+	if err != nil {
+		return -1, -1, err
+	}
+	rgid, err := toContainer(gid, i.GIDMaps)
+	return ruid, rgid, err
+}
+
+// Empty returns true if there are no id mappings
+func (i IdentityMapping) Empty() bool {
+	return len(i.UIDMaps) == 0 && len(i.GIDMaps) == 0
+}
diff --git a/pkg/idtools/idtools_unix.go b/vendor/github.com/moby/sys/user/idtools_unix.go
similarity index 62%
rename from pkg/idtools/idtools_unix.go
rename to vendor/github.com/moby/sys/user/idtools_unix.go
index 1f11fe4740..4e39d2446b 100644
--- a/pkg/idtools/idtools_unix.go
+++ b/vendor/github.com/moby/sys/user/idtools_unix.go
@@ -1,6 +1,6 @@
 //go:build !windows
 
-package idtools
+package user
 
 import (
 	"fmt"
@@ -8,11 +8,9 @@ import (
 	"path/filepath"
 	"strconv"
 	"syscall"
-
-	"github.com/moby/sys/user"
 )
 
-func mkdirAs(path string, mode os.FileMode, owner Identity, mkAll, chownExisting bool) error {
+func mkdirAs(path string, mode os.FileMode, uid, gid int, mkAll, onlyNew bool) error {
 	path, err := filepath.Abs(path)
 	if err != nil {
 		return err
@@ -23,21 +21,21 @@ func mkdirAs(path string, mode os.FileMode, owner Identity, mkAll, chownExisting
 		if !stat.IsDir() {
 			return &os.PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
 		}
-		if !chownExisting {
+		if onlyNew {
 			return nil
 		}
 
 		// short-circuit -- we were called with an existing directory and chown was requested
-		return setPermissions(path, mode, owner, stat)
+		return setPermissions(path, mode, uid, gid, stat)
 	}
 
 	// make an array containing the original path asked for, plus (for mkAll == true)
 	// all path components leading up to the complete path that don't exist before we MkdirAll
-	// so that we can chown all of them properly at the end.  If chownExisting is false, we won't
+	// so that we can chown all of them properly at the end.  If onlyNew is true, we won't
 	// chown the full directory path if it exists
 	var paths []string
 	if os.IsNotExist(err) {
-		paths = []string{path}
+		paths = append(paths, path)
 	}
 
 	if mkAll {
@@ -49,7 +47,7 @@ func mkdirAs(path string, mode os.FileMode, owner Identity, mkAll, chownExisting
 			if dirPath == "/" {
 				break
 			}
-			if _, err = os.Stat(dirPath); err != nil && os.IsNotExist(err) {
+			if _, err = os.Stat(dirPath); os.IsNotExist(err) {
 				paths = append(paths, dirPath)
 			}
 		}
@@ -62,39 +60,18 @@ func mkdirAs(path string, mode os.FileMode, owner Identity, mkAll, chownExisting
 	// even if it existed, we will chown the requested path + any subpaths that
 	// didn't exist when we called MkdirAll
 	for _, pathComponent := range paths {
-		if err = setPermissions(pathComponent, mode, owner, nil); err != nil {
+		if err = setPermissions(pathComponent, mode, uid, gid, nil); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-// LookupUser uses traditional local system files lookup (from libcontainer/user) on a username
-//
-// Deprecated: use [user.LookupUser] instead
-func LookupUser(name string) (user.User, error) {
-	return user.LookupUser(name)
-}
-
-// LookupUID uses traditional local system files lookup (from libcontainer/user) on a uid
-//
-// Deprecated: use [user.LookupUid] instead
-func LookupUID(uid int) (user.User, error) {
-	return user.LookupUid(uid)
-}
-
-// LookupGroup uses traditional local system files lookup (from libcontainer/user) on a group name,
-//
-// Deprecated: use [user.LookupGroup] instead
-func LookupGroup(name string) (user.Group, error) {
-	return user.LookupGroup(name)
-}
-
 // setPermissions performs a chown/chmod only if the uid/gid don't match what's requested
 // Normally a Chown is a no-op if uid/gid match, but in some cases this can still cause an error, e.g. if the
 // dir is on an NFS share, so don't call chown unless we absolutely must.
 // Likewise for setting permissions.
-func setPermissions(p string, mode os.FileMode, owner Identity, stat os.FileInfo) error {
+func setPermissions(p string, mode os.FileMode, uid, gid int, stat os.FileInfo) error {
 	if stat == nil {
 		var err error
 		stat, err = os.Stat(p)
@@ -108,10 +85,10 @@ func setPermissions(p string, mode os.FileMode, owner Identity, stat os.FileInfo
 		}
 	}
 	ssi := stat.Sys().(*syscall.Stat_t)
-	if ssi.Uid == uint32(owner.UID) && ssi.Gid == uint32(owner.GID) {
+	if ssi.Uid == uint32(uid) && ssi.Gid == uint32(gid) {
 		return nil
 	}
-	return os.Chown(p, owner.UID, owner.GID)
+	return os.Chown(p, uid, gid)
 }
 
 // LoadIdentityMapping takes a requested username and
@@ -119,9 +96,9 @@ func setPermissions(p string, mode os.FileMode, owner Identity, stat os.FileInfo
 // proper uid and gid remapping ranges for that user/group pair
 func LoadIdentityMapping(name string) (IdentityMapping, error) {
 	// TODO: Consider adding support for calling out to "getent"
-	usr, err := user.LookupUser(name)
+	usr, err := LookupUser(name)
 	if err != nil {
-		return IdentityMapping{}, fmt.Errorf("could not get user for username %s: %v", name, err)
+		return IdentityMapping{}, fmt.Errorf("could not get user for username %s: %w", name, err)
 	}
 
 	subuidRanges, err := lookupSubRangesFile("/etc/subuid", usr)
@@ -139,9 +116,9 @@ func LoadIdentityMapping(name string) (IdentityMapping, error) {
 	}, nil
 }
 
-func lookupSubRangesFile(path string, usr user.User) ([]IDMap, error) {
+func lookupSubRangesFile(path string, usr User) ([]IDMap, error) {
 	uidstr := strconv.Itoa(usr.Uid)
-	rangeList, err := user.ParseSubIDFileFilter(path, func(sid user.SubID) bool {
+	rangeList, err := ParseSubIDFileFilter(path, func(sid SubID) bool {
 		return sid.Name == usr.Name || sid.Name == uidstr
 	})
 	if err != nil {
@@ -153,14 +130,14 @@ func lookupSubRangesFile(path string, usr user.User) ([]IDMap, error) {
 
 	idMap := []IDMap{}
 
-	containerID := 0
+	var containerID int64
 	for _, idrange := range rangeList {
 		idMap = append(idMap, IDMap{
-			ContainerID: containerID,
-			HostID:      int(idrange.SubID),
-			Size:        int(idrange.Count),
+			ID:       containerID,
+			ParentID: idrange.SubID,
+			Count:    idrange.Count,
 		})
-		containerID = containerID + int(idrange.Count)
+		containerID = containerID + idrange.Count
 	}
 	return idMap, nil
 }
diff --git a/vendor/github.com/moby/sys/user/idtools_windows.go b/vendor/github.com/moby/sys/user/idtools_windows.go
new file mode 100644
index 0000000000..9de730cafb
--- /dev/null
+++ b/vendor/github.com/moby/sys/user/idtools_windows.go
@@ -0,0 +1,13 @@
+package user
+
+import (
+	"os"
+)
+
+// This is currently a wrapper around [os.MkdirAll] since currently
+// permissions aren't set through this path, the identity isn't utilized.
+// Ownership is handled elsewhere, but in the future could be support here
+// too.
+func mkdirAs(path string, _ os.FileMode, _, _ int, _, _ bool) error {
+	return os.MkdirAll(path, 0)
+}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 197d0b8376..a750e1c4d4 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1025,7 +1025,7 @@ github.com/moby/sys/signal
 # github.com/moby/sys/symlink v0.3.0
 ## explicit; go 1.17
 github.com/moby/sys/symlink
-# github.com/moby/sys/user v0.3.0
+# github.com/moby/sys/user v0.4.0
 ## explicit; go 1.17
 github.com/moby/sys/user
 # github.com/moby/sys/userns v0.1.0

From 3fc36bcac49cb881abe16a0bd4a469a02fd6af11 Mon Sep 17 00:00:00 2001
From: Derek McGowan <derek@mcg.dev>
Date: Sat, 1 Mar 2025 01:57:51 -0800
Subject: [PATCH 2/3] Update daemon to use moby sys/user identity mapping

Signed-off-by: Derek McGowan <derek@mcg.dev>
---
 daemon/archive_tarcopyoptions.go     |  3 ++-
 daemon/container_operations_unix.go  | 27 +++++++++++----------
 daemon/create_unix.go                |  9 +++----
 daemon/daemon.go                     | 31 ++++++++++++------------
 daemon/daemon_unix.go                | 36 +++++++++++++++-------------
 daemon/daemon_windows.go             | 10 ++++----
 daemon/export.go                     |  3 ++-
 daemon/info.go                       |  2 +-
 daemon/oci_linux.go                  | 11 +++++----
 daemon/volumes_unix.go               |  8 ++++---
 daemon/workdir.go                    |  5 +++-
 internal/usergroup/add_linux_test.go |  7 +++---
 internal/usergroup/lookup_unix.go    | 27 ++++++++++-----------
 pkg/idtools/idtools.go               | 25 +++++++++++++++++++
 14 files changed, 119 insertions(+), 85 deletions(-)

diff --git a/daemon/archive_tarcopyoptions.go b/daemon/archive_tarcopyoptions.go
index 2e2141042e..42bd1ace2b 100644
--- a/daemon/archive_tarcopyoptions.go
+++ b/daemon/archive_tarcopyoptions.go
@@ -2,6 +2,7 @@ package daemon // import "github.com/docker/docker/daemon"
 
 import (
 	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/idtools"
 )
 
 // defaultTarCopyOptions is the setting that is used when unpacking an archive
@@ -9,6 +10,6 @@ import (
 func (daemon *Daemon) defaultTarCopyOptions(noOverwriteDirNonDir bool) *archive.TarOptions {
 	return &archive.TarOptions{
 		NoOverwriteDirNonDir: noOverwriteDirNonDir,
-		IDMap:                daemon.idMapping,
+		IDMap:                idtools.FromUserIdentityMapping(daemon.idMapping),
 	}
 }
diff --git a/daemon/container_operations_unix.go b/daemon/container_operations_unix.go
index cda101673d..dd8351dd57 100644
--- a/daemon/container_operations_unix.go
+++ b/daemon/container_operations_unix.go
@@ -23,6 +23,7 @@ import (
 	"github.com/docker/docker/pkg/process"
 	"github.com/docker/docker/pkg/stringid"
 	"github.com/moby/sys/mount"
+	"github.com/moby/sys/user"
 	"github.com/opencontainers/selinux/go-selinux/label"
 	"github.com/pkg/errors"
 	"go.opentelemetry.io/otel"
@@ -251,14 +252,14 @@ func (daemon *Daemon) setupIPCDirs(ctr *container.Container) error {
 		fallthrough
 
 	case ipcMode.IsShareable():
-		rootIDs := daemon.idMapping.RootPair()
+		uid, gid := daemon.idMapping.RootPair()
 		if !ctr.HasMountFor("/dev/shm") {
 			shmPath, err := ctr.ShmResourcePath()
 			if err != nil {
 				return err
 			}
 
-			if err := idtools.MkdirAllAndChown(shmPath, 0o700, rootIDs); err != nil {
+			if err := user.MkdirAllAndChown(shmPath, 0o700, uid, gid); err != nil {
 				return err
 			}
 
@@ -266,7 +267,7 @@ func (daemon *Daemon) setupIPCDirs(ctr *container.Container) error {
 			if err := unix.Mount("shm", shmPath, "tmpfs", uintptr(unix.MS_NOEXEC|unix.MS_NOSUID|unix.MS_NODEV), label.FormatMountLabel(shmproperty, ctr.GetMountLabel())); err != nil {
 				return fmt.Errorf("mounting shm tmpfs: %s", err)
 			}
-			if err := os.Chown(shmPath, rootIDs.UID, rootIDs.GID); err != nil {
+			if err := os.Chown(shmPath, uid, gid); err != nil {
 				return err
 			}
 			ctr.ShmPath = shmPath
@@ -298,7 +299,7 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 	}
 
 	// retrieve possible remapped range start for root UID, GID
-	rootIDs := daemon.idMapping.RootPair()
+	ruid, rgid := daemon.idMapping.RootPair()
 
 	for _, s := range ctr.SecretReferences {
 		// TODO (ehazlett): use type switch when more are supported
@@ -313,7 +314,7 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 		if err != nil {
 			return errors.Wrap(err, "error getting secret file path")
 		}
-		if err := idtools.MkdirAllAndChown(filepath.Dir(fPath), 0o700, rootIDs); err != nil {
+		if err := user.MkdirAllAndChown(filepath.Dir(fPath), 0o700, ruid, rgid); err != nil {
 			return errors.Wrap(err, "error creating secret mount path")
 		}
 
@@ -338,7 +339,7 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 			return err
 		}
 
-		if err := os.Chown(fPath, rootIDs.UID+uid, rootIDs.GID+gid); err != nil {
+		if err := os.Chown(fPath, ruid+uid, rgid+gid); err != nil {
 			return errors.Wrap(err, "error setting ownership for secret")
 		}
 		if err := os.Chmod(fPath, s.File.Mode); err != nil {
@@ -364,7 +365,7 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 		if err != nil {
 			return errors.Wrap(err, "error getting config file path for container")
 		}
-		if err := idtools.MkdirAllAndChown(filepath.Dir(fPath), 0o700, rootIDs); err != nil {
+		if err := user.MkdirAllAndChown(filepath.Dir(fPath), 0o700, ruid, rgid); err != nil {
 			return errors.Wrap(err, "error creating config mount path")
 		}
 
@@ -389,7 +390,7 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 			return err
 		}
 
-		if err := os.Chown(fPath, rootIDs.UID+uid, rootIDs.GID+gid); err != nil {
+		if err := os.Chown(fPath, ruid+uid, rgid+gid); err != nil {
 			return errors.Wrap(err, "error setting ownership for config")
 		}
 		if err := os.Chmod(fPath, configRef.File.Mode); err != nil {
@@ -404,18 +405,18 @@ func (daemon *Daemon) setupSecretDir(ctr *container.Container) (setupErr error)
 // In practice this is using a tmpfs mount and is used for both "configs" and "secrets"
 func (daemon *Daemon) createSecretsDir(ctr *container.Container) error {
 	// retrieve possible remapped range start for root UID, GID
-	rootIDs := daemon.idMapping.RootPair()
+	uid, gid := daemon.idMapping.RootPair()
 	dir, err := ctr.SecretMountPath()
 	if err != nil {
 		return errors.Wrap(err, "error getting container secrets dir")
 	}
 
 	// create tmpfs
-	if err := idtools.MkdirAllAndChown(dir, 0o700, rootIDs); err != nil {
+	if err := user.MkdirAllAndChown(dir, 0o700, uid, gid); err != nil {
 		return errors.Wrap(err, "error creating secret local mount path")
 	}
 
-	tmpfsOwnership := fmt.Sprintf("uid=%d,gid=%d", rootIDs.UID, rootIDs.GID)
+	tmpfsOwnership := fmt.Sprintf("uid=%d,gid=%d", uid, gid)
 	if err := mount.Mount("tmpfs", dir, "tmpfs", "nodev,nosuid,noexec,"+tmpfsOwnership); err != nil {
 		return errors.Wrap(err, "unable to setup secret mount")
 	}
@@ -430,8 +431,8 @@ func (daemon *Daemon) remountSecretDir(ctr *container.Container) error {
 	if err := label.Relabel(dir, ctr.MountLabel, false); err != nil {
 		log.G(context.TODO()).WithError(err).WithField("dir", dir).Warn("Error while attempting to set selinux label")
 	}
-	rootIDs := daemon.idMapping.RootPair()
-	tmpfsOwnership := fmt.Sprintf("uid=%d,gid=%d", rootIDs.UID, rootIDs.GID)
+	uid, gid := daemon.idMapping.RootPair()
+	tmpfsOwnership := fmt.Sprintf("uid=%d,gid=%d", uid, gid)
 
 	// remount secrets ro
 	if err := mount.Mount("tmpfs", dir, "tmpfs", "remount,ro,"+tmpfsOwnership); err != nil {
diff --git a/daemon/create_unix.go b/daemon/create_unix.go
index d91bf94fec..7853a9a5c6 100644
--- a/daemon/create_unix.go
+++ b/daemon/create_unix.go
@@ -14,6 +14,7 @@ import (
 	"github.com/docker/docker/container"
 	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/oci"
+	"github.com/docker/docker/pkg/idtools"
 	volumemounts "github.com/docker/docker/volume/mounts"
 	volumeopts "github.com/docker/docker/volume/service/opts"
 	"github.com/opencontainers/selinux/go-selinux/label"
@@ -27,8 +28,8 @@ func (daemon *Daemon) createContainerOSSpecificSettings(ctx context.Context, con
 	}
 	defer daemon.Unmount(container)
 
-	rootIDs := daemon.idMapping.RootPair()
-	if err := container.SetupWorkingDirectory(rootIDs); err != nil {
+	uid, gid := daemon.idMapping.RootPair()
+	if err := container.SetupWorkingDirectory(idtools.Identity{UID: uid, GID: gid}); err != nil {
 		return err
 	}
 
@@ -107,8 +108,8 @@ func (daemon *Daemon) populateVolume(ctx context.Context, c *container.Container
 		}
 		return err
 	}
-
-	volumePath, cleanup, err := mnt.Setup(ctx, c.MountLabel, daemon.idMapping.RootPair(), nil)
+	uid, gid := daemon.idMapping.RootPair()
+	volumePath, cleanup, err := mnt.Setup(ctx, c.MountLabel, idtools.Identity{UID: uid, GID: gid}, nil)
 	if err != nil {
 		if errdefs.IsNotFound(err) {
 			return nil
diff --git a/daemon/daemon.go b/daemon/daemon.go
index 395f4cc351..50bb480d3b 100644
--- a/daemon/daemon.go
+++ b/daemon/daemon.go
@@ -75,6 +75,7 @@ import (
 	"github.com/moby/buildkit/util/grpcerrors"
 	"github.com/moby/buildkit/util/tracing"
 	"github.com/moby/locker"
+	"github.com/moby/sys/user"
 	"github.com/moby/sys/userns"
 	"github.com/pkg/errors"
 	"go.etcd.io/bbolt"
@@ -113,7 +114,7 @@ type Daemon struct {
 	sysInfoOnce       sync.Once
 	sysInfo           *sysinfo.SysInfo
 	shutdown          bool
-	idMapping         idtools.IdentityMapping
+	idMapping         user.IdentityMapping
 	PluginStore       *plugin.Store // TODO: remove
 	pluginManager     *plugin.Manager
 	linkIndex         *linkIndex
@@ -791,7 +792,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 	if err != nil {
 		return nil, err
 	}
-	rootIDs := idMapping.RootPair()
+	uid, gid := idMapping.RootPair()
 
 	// set up the tmpDir to use a canonical path
 	tmp, err := prepareTempDir(config.Root)
@@ -878,10 +879,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 	}
 
 	daemonRepo := filepath.Join(cfgStore.Root, "containers")
-	if err := idtools.MkdirAllAndChown(daemonRepo, 0o710, idtools.Identity{
-		UID: idtools.CurrentIdentity().UID,
-		GID: rootIDs.GID,
-	}); err != nil {
+	if err := user.MkdirAllAndChown(daemonRepo, 0o710, os.Getuid(), gid); err != nil {
 		return nil, err
 	}
 
@@ -999,7 +997,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 	}
 	log.G(ctx).Debugf("Using default logging driver %s", d.defaultLogConfig.Type)
 
-	d.volumes, err = volumesservice.NewVolumeService(cfgStore.Root, d.PluginStore, rootIDs, d)
+	d.volumes, err = volumesservice.NewVolumeService(cfgStore.Root, d.PluginStore, idtools.Identity{UID: uid, GID: gid}, d)
 	if err != nil {
 		return nil, err
 	}
@@ -1074,15 +1072,15 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 			RegistryHosts:   d.RegistryHosts,
 			Registry:        d.registryService,
 			EventsService:   d.EventsService,
-			IDMapping:       idMapping,
-			RefCountMounter: snapshotter.NewMounter(config.Root, driverName, idMapping),
+			IDMapping:       idtools.FromUserIdentityMapping(idMapping),
+			RefCountMounter: snapshotter.NewMounter(config.Root, driverName, idtools.FromUserIdentityMapping(idMapping)),
 		})
 	} else {
 		layerStore, err := layer.NewStoreFromOptions(layer.StoreOptions{
 			Root:               cfgStore.Root,
 			GraphDriver:        driverName,
 			GraphDriverOptions: cfgStore.GraphOptions,
-			IDMapping:          idMapping,
+			IDMapping:          idtools.FromUserIdentityMapping(idMapping),
 		})
 		if err != nil {
 			return nil, err
@@ -1423,7 +1421,7 @@ func prepareTempDir(rootDir string) (string, error) {
 			}
 		}
 	}
-	return tmpDir, idtools.MkdirAllAndChown(tmpDir, 0o700, idtools.CurrentIdentity())
+	return tmpDir, user.MkdirAllAndChown(tmpDir, 0o700, os.Getuid(), os.Getegid())
 }
 
 func (daemon *Daemon) setGenericResources(conf *config.Config) error {
@@ -1545,7 +1543,8 @@ func CreateDaemonRoot(config *config.Config) error {
 	if err != nil {
 		return err
 	}
-	return setupDaemonRoot(config, realRoot, idMapping.RootPair())
+	uid, gid := idMapping.RootPair()
+	return setupDaemonRoot(config, realRoot, uid, gid)
 }
 
 // RemapContainerdNamespaces returns the right containerd namespaces to use:
@@ -1561,16 +1560,16 @@ func RemapContainerdNamespaces(config *config.Config) (ns string, pluginNs strin
 	if idMapping.Empty() {
 		return config.ContainerdNamespace, config.ContainerdPluginNamespace, nil
 	}
-	root := idMapping.RootPair()
+	uid, gid := idMapping.RootPair()
 
 	ns = config.ContainerdNamespace
 	if _, ok := config.ValuesSet["containerd-namespace"]; !ok {
-		ns = fmt.Sprintf("%s-%d.%d", config.ContainerdNamespace, root.UID, root.GID)
+		ns = fmt.Sprintf("%s-%d.%d", config.ContainerdNamespace, uid, gid)
 	}
 
 	pluginNs = config.ContainerdPluginNamespace
 	if _, ok := config.ValuesSet["containerd-plugin-namespace"]; !ok {
-		pluginNs = fmt.Sprintf("%s-%d.%d", config.ContainerdPluginNamespace, root.UID, root.GID)
+		pluginNs = fmt.Sprintf("%s-%d.%d", config.ContainerdPluginNamespace, uid, gid)
 	}
 
 	return ns, pluginNs, nil
@@ -1601,7 +1600,7 @@ func (daemon *Daemon) GetAttachmentStore() *network.AttachmentStore {
 
 // IdentityMapping returns uid/gid mapping or a SID (in the case of Windows) for the builder
 func (daemon *Daemon) IdentityMapping() idtools.IdentityMapping {
-	return daemon.idMapping
+	return idtools.FromUserIdentityMapping(daemon.idMapping)
 }
 
 // ImageService returns the Daemon's ImageService
diff --git a/daemon/daemon_unix.go b/daemon/daemon_unix.go
index b988b07a8e..a36bdee907 100644
--- a/daemon/daemon_unix.go
+++ b/daemon/daemon_unix.go
@@ -45,6 +45,7 @@ import (
 	"github.com/docker/docker/runconfig"
 	volumemounts "github.com/docker/docker/volume/mounts"
 	"github.com/moby/sys/mount"
+	"github.com/moby/sys/user"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/selinux/go-selinux"
 	"github.com/opencontainers/selinux/go-selinux/label"
@@ -1250,9 +1251,10 @@ func removeDefaultBridgeInterface() {
 	}
 }
 
-func setupInitLayer(idMapping idtools.IdentityMapping) func(string) error {
+func setupInitLayer(idMapping user.IdentityMapping) func(string) error {
 	return func(initPath string) error {
-		return initlayer.Setup(initPath, idMapping.RootPair())
+		uid, gid := idMapping.RootPair()
+		return initlayer.Setup(initPath, idtools.Identity{UID: uid, GID: gid})
 	}
 }
 
@@ -1349,9 +1351,9 @@ func parseRemappedRoot(usergrp string) (string, string, error) {
 	return username, groupname, nil
 }
 
-func setupRemappedRoot(config *config.Config) (idtools.IdentityMapping, error) {
+func setupRemappedRoot(config *config.Config) (user.IdentityMapping, error) {
 	if runtime.GOOS != "linux" && config.RemappedRoot != "" {
-		return idtools.IdentityMapping{}, fmt.Errorf("User namespaces are only supported on Linux")
+		return user.IdentityMapping{}, fmt.Errorf("User namespaces are only supported on Linux")
 	}
 
 	// if the daemon was started with remapped root option, parse
@@ -1359,13 +1361,13 @@ func setupRemappedRoot(config *config.Config) (idtools.IdentityMapping, error) {
 	if config.RemappedRoot != "" {
 		username, groupname, err := parseRemappedRoot(config.RemappedRoot)
 		if err != nil {
-			return idtools.IdentityMapping{}, err
+			return user.IdentityMapping{}, err
 		}
 		if username == "root" {
 			// Cannot setup user namespaces with a 1-to-1 mapping; "--root=0:0" is a no-op
 			// effectively
 			log.G(context.TODO()).Warn("User namespaces: root cannot be remapped with itself; user namespaces are OFF")
-			return idtools.IdentityMapping{}, nil
+			return user.IdentityMapping{}, nil
 		}
 		log.G(context.TODO()).Infof("User namespaces: ID ranges will be mapped to subuid/subgid ranges of: %s", username)
 		// update remapped root setting now that we have resolved them to actual names
@@ -1373,14 +1375,14 @@ func setupRemappedRoot(config *config.Config) (idtools.IdentityMapping, error) {
 
 		mappings, err := usergroup.LoadIdentityMapping(username)
 		if err != nil {
-			return idtools.IdentityMapping{}, errors.Wrap(err, "Can't create ID mappings")
+			return user.IdentityMapping{}, errors.Wrap(err, "Can't create ID mappings")
 		}
 		return mappings, nil
 	}
-	return idtools.IdentityMapping{}, nil
+	return user.IdentityMapping{}, nil
 }
 
-func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools.Identity) error {
+func setupDaemonRoot(config *config.Config, rootDir string, uid, gid int) error {
 	config.Root = rootDir
 	// the docker root metadata directory needs to have execute permissions for all users (g+x,o+x)
 	// so that syscalls executing as non-root, operating on subdirectories of the graph root
@@ -1400,9 +1402,9 @@ func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools
 		}
 	}
 
-	id := idtools.Identity{UID: idtools.CurrentIdentity().UID, GID: remappedRoot.GID}
+	curuid := os.Getuid()
 	// First make sure the current root dir has the correct perms.
-	if err := idtools.MkdirAllAndChown(config.Root, 0o710, id); err != nil {
+	if err := user.MkdirAllAndChown(config.Root, 0o710, curuid, gid); err != nil {
 		return errors.Wrapf(err, "could not create or set daemon root permissions: %s", config.Root)
 	}
 
@@ -1411,10 +1413,10 @@ func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools
 	// a new subdirectory with ownership set to the remapped uid/gid (so as to allow
 	// `chdir()` to work for containers namespaced to that uid/gid)
 	if config.RemappedRoot != "" {
-		config.Root = filepath.Join(rootDir, fmt.Sprintf("%d.%d", remappedRoot.UID, remappedRoot.GID))
+		config.Root = filepath.Join(rootDir, fmt.Sprintf("%d.%d", uid, gid))
 		log.G(context.TODO()).Debugf("Creating user namespaced daemon root: %s", config.Root)
 		// Create the root directory if it doesn't exist
-		if err := idtools.MkdirAllAndChown(config.Root, 0o710, id); err != nil {
+		if err := user.MkdirAllAndChown(config.Root, 0o710, curuid, gid); err != nil {
 			return fmt.Errorf("Cannot create daemon root: %s: %v", config.Root, err)
 		}
 		// we also need to verify that any pre-existing directories in the path to
@@ -1427,7 +1429,7 @@ func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools
 			if dirPath == "/" {
 				break
 			}
-			if !canAccess(dirPath, remappedRoot) {
+			if !canAccess(dirPath, uid, gid) {
 				return fmt.Errorf("a subdirectory in your graphroot path (%s) restricts access to the remapped root uid/gid; please fix by allowing 'o+x' permissions on existing directories", config.Root)
 			}
 		}
@@ -1445,7 +1447,7 @@ func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools
 // Note: this is a very rudimentary check, and may not produce accurate results,
 // so should not be used for anything other than the current use, see:
 // https://github.com/moby/moby/issues/43724
-func canAccess(path string, pair idtools.Identity) bool {
+func canAccess(path string, uid, gid int) bool {
 	statInfo, err := os.Stat(path)
 	if err != nil {
 		return false
@@ -1456,11 +1458,11 @@ func canAccess(path string, pair idtools.Identity) bool {
 		return true
 	}
 	ssi := statInfo.Sys().(*syscall.Stat_t)
-	if ssi.Uid == uint32(pair.UID) && (perms&0o100 == 0o100) {
+	if ssi.Uid == uint32(uid) && (perms&0o100 == 0o100) {
 		// owner access.
 		return true
 	}
-	if ssi.Gid == uint32(pair.GID) && (perms&0o010 == 0o010) {
+	if ssi.Gid == uint32(gid) && (perms&0o010 == 0o010) {
 		// group access.
 		return true
 	}
diff --git a/daemon/daemon_windows.go b/daemon/daemon_windows.go
index 5a099c1800..20d173c08c 100644
--- a/daemon/daemon_windows.go
+++ b/daemon/daemon_windows.go
@@ -24,10 +24,10 @@ import (
 	"github.com/docker/docker/libnetwork/netlabel"
 	"github.com/docker/docker/libnetwork/options"
 	"github.com/docker/docker/libnetwork/scope"
-	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/parsers/operatingsystem"
 	"github.com/docker/docker/pkg/sysinfo"
 	"github.com/docker/docker/pkg/system"
+	"github.com/moby/sys/user"
 	"github.com/pkg/errors"
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc/mgr"
@@ -56,7 +56,7 @@ func (daemon *Daemon) parseSecurityOpt(daemonCfg *config.Config, securityOptions
 	return nil
 }
 
-func setupInitLayer(idMapping idtools.IdentityMapping) func(string) error {
+func setupInitLayer(idMapping user.IdentityMapping) func(string) error {
 	return nil
 }
 
@@ -462,11 +462,11 @@ func recursiveUnmount(_ string) error {
 	return nil
 }
 
-func setupRemappedRoot(config *config.Config) (idtools.IdentityMapping, error) {
-	return idtools.IdentityMapping{}, nil
+func setupRemappedRoot(config *config.Config) (user.IdentityMapping, error) {
+	return user.IdentityMapping{}, nil
 }
 
-func setupDaemonRoot(config *config.Config, rootDir string, rootIdentity idtools.Identity) error {
+func setupDaemonRoot(config *config.Config, rootDir string, uid, gid int) error {
 	config.Root = rootDir
 	// Create the root directory if it doesn't exists
 	if err := system.MkdirAllWithACL(config.Root, 0, system.SddlAdministratorsLocalSystem); err != nil {
diff --git a/daemon/export.go b/daemon/export.go
index d01057cd26..b3aaca8477 100644
--- a/daemon/export.go
+++ b/daemon/export.go
@@ -11,6 +11,7 @@ import (
 	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/pkg/archive"
 	"github.com/docker/docker/pkg/chrootarchive"
+	"github.com/docker/docker/pkg/idtools"
 )
 
 // ContainerExport writes the contents of the container to the given
@@ -65,7 +66,7 @@ func (daemon *Daemon) containerExport(ctx context.Context, ctr *container.Contai
 
 	archv, err := chrootarchive.Tar(basefs, &archive.TarOptions{
 		Compression: archive.Uncompressed,
-		IDMap:       daemon.idMapping,
+		IDMap:       idtools.FromUserIdentityMapping(daemon.idMapping),
 	}, basefs)
 	if err != nil {
 		return err
diff --git a/daemon/info.go b/daemon/info.go
index 339d9664ef..ebc3fa280c 100644
--- a/daemon/info.go
+++ b/daemon/info.go
@@ -191,7 +191,7 @@ func (daemon *Daemon) fillSecurityOptions(v *system.Info, sysInfo *sysinfo.SysIn
 	if selinux.GetEnabled() {
 		securityOptions = append(securityOptions, "name=selinux")
 	}
-	if rootIDs := daemon.idMapping.RootPair(); rootIDs.UID != 0 || rootIDs.GID != 0 {
+	if uid, gid := daemon.idMapping.RootPair(); uid != 0 || gid != 0 {
 		securityOptions = append(securityOptions, "name=userns")
 	}
 	if Rootless(cfg) {
diff --git a/daemon/oci_linux.go b/daemon/oci_linux.go
index 1529dee046..28c7543527 100644
--- a/daemon/oci_linux.go
+++ b/daemon/oci_linux.go
@@ -360,13 +360,13 @@ func WithNamespaces(daemon *Daemon, c *container.Container) coci.SpecOpts {
 	}
 }
 
-func specMapping(s []idtools.IDMap) []specs.LinuxIDMapping {
+func specMapping(s []user.IDMap) []specs.LinuxIDMapping {
 	var ids []specs.LinuxIDMapping
 	for _, item := range s {
 		ids = append(ids, specs.LinuxIDMapping{
-			HostID:      uint32(item.HostID),
-			ContainerID: uint32(item.ContainerID),
-			Size:        uint32(item.Size),
+			HostID:      uint32(item.ParentID),
+			ContainerID: uint32(item.ID),
+			Size:        uint32(item.Count),
 		})
 	}
 	return ids
@@ -712,7 +712,8 @@ func withCommonOptions(daemon *Daemon, daemonCfg *dconfig.Config, c *container.C
 			Path:     c.BaseFS,
 			Readonly: c.HostConfig.ReadonlyRootfs,
 		}
-		if err := c.SetupWorkingDirectory(daemon.idMapping.RootPair()); err != nil {
+		uid, gid := daemon.idMapping.RootPair()
+		if err := c.SetupWorkingDirectory(idtools.Identity{UID: uid, GID: gid}); err != nil {
 			return err
 		}
 		cwd := c.Config.WorkingDir
diff --git a/daemon/volumes_unix.go b/daemon/volumes_unix.go
index 0a04fe2369..05f4d56fea 100644
--- a/daemon/volumes_unix.go
+++ b/daemon/volumes_unix.go
@@ -14,6 +14,7 @@ import (
 	mounttypes "github.com/docker/docker/api/types/mount"
 	"github.com/docker/docker/container"
 	"github.com/docker/docker/internal/cleanups"
+	"github.com/docker/docker/pkg/idtools"
 	volumemounts "github.com/docker/docker/volume/mounts"
 	"github.com/pkg/errors"
 )
@@ -61,7 +62,8 @@ func (daemon *Daemon) setupMounts(ctx context.Context, c *container.Container) (
 			return nil
 		}
 
-		path, clean, err := m.Setup(ctx, c.MountLabel, daemon.idMapping.RootPair(), checkfunc)
+		uid, gid := daemon.idMapping.RootPair()
+		path, clean, err := m.Setup(ctx, c.MountLabel, idtools.Identity{UID: uid, GID: gid}, checkfunc)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -106,13 +108,13 @@ func (daemon *Daemon) setupMounts(ctx context.Context, c *container.Container) (
 	// if we are going to mount any of the network files from container
 	// metadata, the ownership must be set properly for potential container
 	// remapped root (user namespaces)
-	rootIDs := daemon.idMapping.RootPair()
+	uid, gid := daemon.idMapping.RootPair()
 	for _, mnt := range netMounts {
 		// we should only modify ownership of network files within our own container
 		// metadata repository. If the user specifies a mount path external, it is
 		// up to the user to make sure the file has proper ownership for userns
 		if strings.Index(mnt.Source, daemon.repository) == 0 {
-			if err := os.Chown(mnt.Source, rootIDs.UID, rootIDs.GID); err != nil {
+			if err := os.Chown(mnt.Source, uid, gid); err != nil {
 				return nil, nil, err
 			}
 		}
diff --git a/daemon/workdir.go b/daemon/workdir.go
index 4c0184998a..0e4885f54f 100644
--- a/daemon/workdir.go
+++ b/daemon/workdir.go
@@ -1,5 +1,7 @@
 package daemon // import "github.com/docker/docker/daemon"
 
+import "github.com/docker/docker/pkg/idtools"
+
 // ContainerCreateWorkdir creates the working directory. This solves the
 // issue arising from https://github.com/docker/docker/issues/27545,
 // which was initially fixed by https://github.com/docker/docker/pull/27884. But that fix
@@ -16,5 +18,6 @@ func (daemon *Daemon) ContainerCreateWorkdir(cID string) error {
 		return err
 	}
 	defer daemon.Unmount(container)
-	return container.SetupWorkingDirectory(daemon.idMapping.RootPair())
+	uid, gid := daemon.idMapping.RootPair()
+	return container.SetupWorkingDirectory(idtools.Identity{UID: uid, GID: gid})
 }
diff --git a/internal/usergroup/add_linux_test.go b/internal/usergroup/add_linux_test.go
index 9308965d15..6e6cc5e430 100644
--- a/internal/usergroup/add_linux_test.go
+++ b/internal/usergroup/add_linux_test.go
@@ -7,7 +7,7 @@ import (
 	"syscall"
 	"testing"
 
-	"github.com/docker/docker/pkg/idtools"
+	mobyuser "github.com/moby/sys/user"
 	"gotest.tools/v3/assert"
 	is "gotest.tools/v3/assert/cmp"
 	"gotest.tools/v3/skip"
@@ -29,14 +29,13 @@ func TestNewIDMappings(t *testing.T) {
 	idMapping, err := LoadIdentityMapping(tempUser.Username)
 	assert.Check(t, err)
 
-	rootUID, rootGID, err := idtools.GetRootUIDGID(idMapping.UIDMaps, idMapping.GIDMaps)
-	assert.Check(t, err)
+	rootUID, rootGID := idMapping.RootPair()
 
 	dirName, err := os.MkdirTemp("", "mkdirall")
 	assert.Check(t, err, "Couldn't create temp directory")
 	defer os.RemoveAll(dirName)
 
-	err = idtools.MkdirAllAndChown(dirName, 0o700, idtools.Identity{UID: rootUID, GID: rootGID})
+	err = mobyuser.MkdirAllAndChown(dirName, 0o700, rootUID, rootGID)
 	assert.Check(t, err, "Couldn't change ownership of file path. Got error")
 	cmd := exec.Command("ls", "-la", dirName)
 	cmd.SysProcAttr = &syscall.SysProcAttr{
diff --git a/internal/usergroup/lookup_unix.go b/internal/usergroup/lookup_unix.go
index 79e9535c04..4ac10ecc52 100644
--- a/internal/usergroup/lookup_unix.go
+++ b/internal/usergroup/lookup_unix.go
@@ -10,7 +10,6 @@ import (
 	"strconv"
 	"syscall"
 
-	"github.com/docker/docker/pkg/idtools"
 	"github.com/moby/sys/user"
 )
 
@@ -140,28 +139,28 @@ func getExitCode(err error) (int, error) {
 // LoadIdentityMapping takes a requested username and
 // using the data from /etc/sub{uid,gid} ranges, creates the
 // proper uid and gid remapping ranges for that user/group pair
-func LoadIdentityMapping(name string) (idtools.IdentityMapping, error) {
+func LoadIdentityMapping(name string) (user.IdentityMapping, error) {
 	usr, err := LookupUser(name)
 	if err != nil {
-		return idtools.IdentityMapping{}, fmt.Errorf("could not get user for username %s: %v", name, err)
+		return user.IdentityMapping{}, fmt.Errorf("could not get user for username %s: %v", name, err)
 	}
 
 	subuidRanges, err := lookupSubRangesFile("/etc/subuid", usr)
 	if err != nil {
-		return idtools.IdentityMapping{}, err
+		return user.IdentityMapping{}, err
 	}
 	subgidRanges, err := lookupSubRangesFile("/etc/subgid", usr)
 	if err != nil {
-		return idtools.IdentityMapping{}, err
+		return user.IdentityMapping{}, err
 	}
 
-	return idtools.IdentityMapping{
+	return user.IdentityMapping{
 		UIDMaps: subuidRanges,
 		GIDMaps: subgidRanges,
 	}, nil
 }
 
-func lookupSubRangesFile(path string, usr user.User) ([]idtools.IDMap, error) {
+func lookupSubRangesFile(path string, usr user.User) ([]user.IDMap, error) {
 	uidstr := strconv.Itoa(usr.Uid)
 	rangeList, err := user.ParseSubIDFileFilter(path, func(sid user.SubID) bool {
 		return sid.Name == usr.Name || sid.Name == uidstr
@@ -173,16 +172,16 @@ func lookupSubRangesFile(path string, usr user.User) ([]idtools.IDMap, error) {
 		return nil, fmt.Errorf("no subuid ranges found for user %q", usr.Name)
 	}
 
-	idMap := []idtools.IDMap{}
+	idMap := []user.IDMap{}
 
-	containerID := 0
+	containerID := int64(0)
 	for _, idrange := range rangeList {
-		idMap = append(idMap, idtools.IDMap{
-			ContainerID: containerID,
-			HostID:      int(idrange.SubID),
-			Size:        int(idrange.Count),
+		idMap = append(idMap, user.IDMap{
+			ID:       containerID,
+			ParentID: idrange.SubID,
+			Count:    idrange.Count,
 		})
-		containerID = containerID + int(idrange.Count)
+		containerID = containerID + idrange.Count
 	}
 	return idMap, nil
 }
diff --git a/pkg/idtools/idtools.go b/pkg/idtools/idtools.go
index 37b184cc62..dcb09c2377 100644
--- a/pkg/idtools/idtools.go
+++ b/pkg/idtools/idtools.go
@@ -119,6 +119,31 @@ type IdentityMapping struct {
 	GIDMaps []IDMap `json:"GIDMaps"`
 }
 
+// FromUserIdentityMapping converts a [user.IdentityMapping] to an [idtools.IdentityMapping].
+//
+// Deprecated: use [user.IdentityMapping] directly, this is transitioning to user package.
+func FromUserIdentityMapping(u user.IdentityMapping) IdentityMapping {
+	return IdentityMapping{
+		UIDMaps: fromUserIDMap(u.UIDMaps),
+		GIDMaps: fromUserIDMap(u.GIDMaps),
+	}
+}
+
+func fromUserIDMap(u []user.IDMap) []IDMap {
+	if u == nil {
+		return nil
+	}
+	m := make([]IDMap, len(u))
+	for i := range u {
+		m[i] = IDMap{
+			ContainerID: int(u[i].ID),
+			HostID:      int(u[i].ParentID),
+			Size:        int(u[i].Count),
+		}
+	}
+	return m
+}
+
 // RootPair returns a uid and gid pair for the root user. The error is ignored
 // because a root user always exists, and the defaults are correct when the uid
 // and gid maps are empty.

From f1ec5bf14f42a2da15ac19fcf651065faf251131 Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Fri, 4 Apr 2025 10:19:43 +0200
Subject: [PATCH 3/3] pkg/idtools: remove tests already covered in
 moby/sys/user

Removes all tests, except for TestGetRootUIDGID and TestToContainer, which
are the only once that have a local implementation that's not covered.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 pkg/idtools/idtools_unix_test.go | 312 -------------------------------
 1 file changed, 312 deletions(-)

diff --git a/pkg/idtools/idtools_unix_test.go b/pkg/idtools/idtools_unix_test.go
index 916c2811e9..6270d66924 100644
--- a/pkg/idtools/idtools_unix_test.go
+++ b/pkg/idtools/idtools_unix_test.go
@@ -3,321 +3,13 @@
 package idtools
 
 import (
-	"fmt"
 	"os"
-	"path/filepath"
 	"testing"
 
-	"golang.org/x/sys/unix"
 	"gotest.tools/v3/assert"
 	is "gotest.tools/v3/assert/cmp"
-	"gotest.tools/v3/skip"
 )
 
-type node struct {
-	uid int
-	gid int
-}
-
-func TestMkdirAllAndChown(t *testing.T) {
-	RequiresRoot(t)
-	dirName, err := os.MkdirTemp("", "mkdirall")
-	if err != nil {
-		t.Fatalf("Couldn't create temp dir: %v", err)
-	}
-	defer os.RemoveAll(dirName)
-
-	testTree := map[string]node{
-		"usr":              {0, 0},
-		"usr/bin":          {0, 0},
-		"lib":              {33, 33},
-		"lib/x86_64":       {45, 45},
-		"lib/x86_64/share": {1, 1},
-	}
-
-	if err := buildTree(dirName, testTree); err != nil {
-		t.Fatal(err)
-	}
-
-	// test adding a directory to a pre-existing dir; only the new dir is owned by the uid/gid
-	if err := MkdirAllAndChown(filepath.Join(dirName, "usr", "share"), 0o755, Identity{UID: 99, GID: 99}); err != nil {
-		t.Fatal(err)
-	}
-	testTree["usr/share"] = node{99, 99}
-	verifyTree, err := readTree(dirName, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := compareTrees(testTree, verifyTree); err != nil {
-		t.Fatal(err)
-	}
-
-	// test 2-deep new directories--both should be owned by the uid/gid pair
-	if err := MkdirAllAndChown(filepath.Join(dirName, "lib", "some", "other"), 0o755, Identity{UID: 101, GID: 101}); err != nil {
-		t.Fatal(err)
-	}
-	testTree["lib/some"] = node{101, 101}
-	testTree["lib/some/other"] = node{101, 101}
-	verifyTree, err = readTree(dirName, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := compareTrees(testTree, verifyTree); err != nil {
-		t.Fatal(err)
-	}
-
-	// test a directory that already exists; should be chowned, but nothing else
-	if err := MkdirAllAndChown(filepath.Join(dirName, "usr"), 0o755, Identity{UID: 102, GID: 102}); err != nil {
-		t.Fatal(err)
-	}
-	testTree["usr"] = node{102, 102}
-	verifyTree, err = readTree(dirName, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := compareTrees(testTree, verifyTree); err != nil {
-		t.Fatal(err)
-	}
-}
-
-func TestMkdirAllAndChownNew(t *testing.T) {
-	RequiresRoot(t)
-	dirName, err := os.MkdirTemp("", "mkdirnew")
-	assert.NilError(t, err)
-	defer os.RemoveAll(dirName)
-
-	testTree := map[string]node{
-		"usr":              {0, 0},
-		"usr/bin":          {0, 0},
-		"lib":              {33, 33},
-		"lib/x86_64":       {45, 45},
-		"lib/x86_64/share": {1, 1},
-	}
-	assert.NilError(t, buildTree(dirName, testTree))
-
-	// test adding a directory to a pre-existing dir; only the new dir is owned by the uid/gid
-	err = MkdirAllAndChownNew(filepath.Join(dirName, "usr", "share"), 0o755, Identity{UID: 99, GID: 99})
-	assert.NilError(t, err)
-
-	testTree["usr/share"] = node{99, 99}
-	verifyTree, err := readTree(dirName, "")
-	assert.NilError(t, err)
-	assert.NilError(t, compareTrees(testTree, verifyTree))
-
-	// test 2-deep new directories--both should be owned by the uid/gid pair
-	err = MkdirAllAndChownNew(filepath.Join(dirName, "lib", "some", "other"), 0o755, Identity{UID: 101, GID: 101})
-	assert.NilError(t, err)
-	testTree["lib/some"] = node{101, 101}
-	testTree["lib/some/other"] = node{101, 101}
-	verifyTree, err = readTree(dirName, "")
-	assert.NilError(t, err)
-	assert.NilError(t, compareTrees(testTree, verifyTree))
-
-	// test a directory that already exists; should NOT be chowned
-	err = MkdirAllAndChownNew(filepath.Join(dirName, "usr"), 0o755, Identity{UID: 102, GID: 102})
-	assert.NilError(t, err)
-	verifyTree, err = readTree(dirName, "")
-	assert.NilError(t, err)
-	assert.NilError(t, compareTrees(testTree, verifyTree))
-}
-
-func TestMkdirAllAndChownNewRelative(t *testing.T) {
-	RequiresRoot(t)
-
-	tests := []struct {
-		in  string
-		out []string
-	}{
-		{
-			in:  "dir1",
-			out: []string{"dir1"},
-		},
-		{
-			in:  "dir2/subdir2",
-			out: []string{"dir2", "dir2/subdir2"},
-		},
-		{
-			in:  "dir3/subdir3/",
-			out: []string{"dir3", "dir3/subdir3"},
-		},
-		{
-			in:  "dir4/subdir4/.",
-			out: []string{"dir4", "dir4/subdir4"},
-		},
-		{
-			in:  "dir5/././subdir5/",
-			out: []string{"dir5", "dir5/subdir5"},
-		},
-		{
-			in:  "./dir6",
-			out: []string{"dir6"},
-		},
-		{
-			in:  "./dir7/subdir7",
-			out: []string{"dir7", "dir7/subdir7"},
-		},
-		{
-			in:  "./dir8/subdir8/",
-			out: []string{"dir8", "dir8/subdir8"},
-		},
-		{
-			in:  "./dir9/subdir9/.",
-			out: []string{"dir9", "dir9/subdir9"},
-		},
-		{
-			in:  "./dir10/././subdir10/",
-			out: []string{"dir10", "dir10/subdir10"},
-		},
-	}
-
-	// Set the current working directory to the temp-dir, as we're
-	// testing relative paths.
-	tmpDir := t.TempDir()
-	setWorkingDirectory(t, tmpDir)
-
-	const expectedUIDGID = 101
-
-	for _, tc := range tests {
-		t.Run(tc.in, func(t *testing.T) {
-			for _, p := range tc.out {
-				_, err := os.Stat(p)
-				assert.ErrorIs(t, err, os.ErrNotExist)
-			}
-
-			err := MkdirAllAndChownNew(tc.in, 0o755, Identity{UID: expectedUIDGID, GID: expectedUIDGID})
-			assert.Check(t, err)
-
-			for _, p := range tc.out {
-				s := &unix.Stat_t{}
-				err = unix.Stat(p, s)
-				if assert.Check(t, err) {
-					assert.Check(t, is.Equal(uint64(s.Uid), uint64(expectedUIDGID)))
-					assert.Check(t, is.Equal(uint64(s.Gid), uint64(expectedUIDGID)))
-				}
-			}
-		})
-	}
-}
-
-// Change the current working directory for the duration of the test. This may
-// break if tests are run in parallel.
-func setWorkingDirectory(t *testing.T, dir string) {
-	t.Helper()
-	cwd, err := os.Getwd()
-	assert.NilError(t, err)
-	t.Cleanup(func() {
-		assert.NilError(t, os.Chdir(cwd))
-	})
-	err = os.Chdir(dir)
-	assert.NilError(t, err)
-}
-
-func TestMkdirAndChown(t *testing.T) {
-	RequiresRoot(t)
-	dirName, err := os.MkdirTemp("", "mkdir")
-	if err != nil {
-		t.Fatalf("Couldn't create temp dir: %v", err)
-	}
-	defer os.RemoveAll(dirName)
-
-	testTree := map[string]node{
-		"usr": {0, 0},
-	}
-	if err := buildTree(dirName, testTree); err != nil {
-		t.Fatal(err)
-	}
-
-	// test a directory that already exists; should just chown to the requested uid/gid
-	if err := MkdirAndChown(filepath.Join(dirName, "usr"), 0o755, Identity{UID: 99, GID: 99}); err != nil {
-		t.Fatal(err)
-	}
-	testTree["usr"] = node{99, 99}
-	verifyTree, err := readTree(dirName, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := compareTrees(testTree, verifyTree); err != nil {
-		t.Fatal(err)
-	}
-
-	// create a subdir under a dir which doesn't exist--should fail
-	if err := MkdirAndChown(filepath.Join(dirName, "usr", "bin", "subdir"), 0o755, Identity{UID: 102, GID: 102}); err == nil {
-		t.Fatalf("Trying to create a directory with Mkdir where the parent doesn't exist should have failed")
-	}
-
-	// create a subdir under an existing dir; should only change the ownership of the new subdir
-	if err := MkdirAndChown(filepath.Join(dirName, "usr", "bin"), 0o755, Identity{UID: 102, GID: 102}); err != nil {
-		t.Fatal(err)
-	}
-	testTree["usr/bin"] = node{102, 102}
-	verifyTree, err = readTree(dirName, "")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := compareTrees(testTree, verifyTree); err != nil {
-		t.Fatal(err)
-	}
-}
-
-func buildTree(base string, tree map[string]node) error {
-	for path, node := range tree {
-		fullPath := filepath.Join(base, path)
-		if err := os.MkdirAll(fullPath, 0o755); err != nil {
-			return fmt.Errorf("couldn't create path: %s; error: %v", fullPath, err)
-		}
-		if err := os.Chown(fullPath, node.uid, node.gid); err != nil {
-			return fmt.Errorf("couldn't chown path: %s; error: %v", fullPath, err)
-		}
-	}
-	return nil
-}
-
-func readTree(base, root string) (map[string]node, error) {
-	tree := make(map[string]node)
-
-	dirInfos, err := os.ReadDir(base)
-	if err != nil {
-		return nil, fmt.Errorf("couldn't read directory entries for %q: %v", base, err)
-	}
-
-	for _, info := range dirInfos {
-		s := &unix.Stat_t{}
-		if err := unix.Stat(filepath.Join(base, info.Name()), s); err != nil {
-			return nil, fmt.Errorf("can't stat file %q: %v", filepath.Join(base, info.Name()), err)
-		}
-		tree[filepath.Join(root, info.Name())] = node{int(s.Uid), int(s.Gid)}
-		if info.IsDir() {
-			// read the subdirectory
-			subtree, err := readTree(filepath.Join(base, info.Name()), filepath.Join(root, info.Name()))
-			if err != nil {
-				return nil, err
-			}
-			for path, nodeinfo := range subtree {
-				tree[path] = nodeinfo
-			}
-		}
-	}
-	return tree, nil
-}
-
-func compareTrees(left, right map[string]node) error {
-	if len(left) != len(right) {
-		return fmt.Errorf("trees aren't the same size")
-	}
-	for path, nodeLeft := range left {
-		if nodeRight, ok := right[path]; ok {
-			if nodeRight.uid != nodeLeft.uid || nodeRight.gid != nodeLeft.gid {
-				// mismatch
-				return fmt.Errorf("mismatched ownership for %q: expected: %d:%d, got: %d:%d", path,
-					nodeLeft.uid, nodeLeft.gid, nodeRight.uid, nodeRight.gid)
-			}
-			continue
-		}
-		return fmt.Errorf("right tree didn't contain path %q", path)
-	}
-	return nil
-}
-
 func TestGetRootUIDGID(t *testing.T) {
 	uidMap := []IDMap{
 		{
@@ -363,7 +55,3 @@ func TestToContainer(t *testing.T) {
 	assert.Check(t, err)
 	assert.Check(t, is.Equal(uidMap[0].ContainerID, containerID))
 }
-
-func RequiresRoot(t *testing.T) {
-	skip.If(t, os.Getuid() != 0, "skipping test that requires root")
-}