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passwd.go
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passwd.go
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// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package util
import (
"fmt"
"os"
"os/exec"
"os/user"
"path/filepath"
"strconv"
"strings"
"github.com/coreos/go-systemd/v22/journal"
"github.com/coreos/ignition/v2/config/util"
"github.com/coreos/ignition/v2/config/v3_5_experimental/types"
"github.com/coreos/ignition/v2/internal/as_user"
"github.com/coreos/ignition/v2/internal/distro"
"golang.org/x/sys/unix"
)
const (
// ignitionSSHAuthorizedkeysMessageID keeps track of the journald
// log related to ssh_authorized_keys information.
ignitionSSHAuthorizedkeysMessageID = "225067b87bbd4a0cb6ab151f82fa364b"
)
func appendIfTrue(args []string, test *bool, newargs string) []string {
if util.IsTrue(test) {
return append(args, newargs)
}
return args
}
func appendIfStringSet(args []string, arg string, str *string) []string {
if util.NotEmpty(str) {
return append(args, arg, *str)
}
return args
}
// EnsureUser ensures that the user exists as described. If the user does not
// yet exist, they will be created, otherwise the existing user will be modified.
// If the `shouldExist` field is set to false and the user already exists, then
// they will be deleted.
func (u Util) EnsureUser(c types.PasswdUser) error {
shouldExist := !util.IsFalse(c.ShouldExist)
exists, err := u.CheckIfUserExists(c)
if err != nil {
return err
}
if !shouldExist {
if exists {
args := []string{"--remove", "--root", u.DestDir, c.Name}
_, err := u.LogCmd(exec.Command(distro.UserdelCmd(), args...),
"deleting user %q", c.Name)
if err != nil {
return fmt.Errorf("failed to delete user %q: %v",
c.Name, err)
}
}
return nil
}
args := []string{"--root", u.DestDir}
var cmd string
if exists {
cmd = distro.UsermodCmd()
if util.NotEmpty(c.HomeDir) {
args = append(args, "--home", *c.HomeDir, "--move-home")
}
} else {
cmd = distro.UseraddCmd()
args = appendIfStringSet(args, "--home-dir", c.HomeDir)
if util.IsTrue(c.NoCreateHome) {
args = append(args, "--no-create-home")
} else {
args = append(args, "--create-home")
}
args = appendIfTrue(args, c.NoUserGroup, "--no-user-group")
args = appendIfTrue(args, c.System, "--system")
args = appendIfTrue(args, c.NoLogInit, "--no-log-init")
}
if c.PasswordHash != nil {
if *c.PasswordHash != "" {
args = append(args, "--password", *c.PasswordHash)
} else {
args = append(args, "--password", "*")
}
} else if !exists {
// Set the user's password to "*" if they don't exist yet and one wasn't
// set to disable password logins
args = append(args, "--password", "*")
}
if c.UID != nil {
args = append(args, "--uid",
strconv.FormatUint(uint64(*c.UID), 10))
}
args = appendIfStringSet(args, "--comment", c.Gecos)
args = appendIfStringSet(args, "--gid", c.PrimaryGroup)
if len(c.Groups) > 0 {
args = append(args, "--groups", strings.Join(translateV2_1PasswdUserGroupSliceToStringSlice(c.Groups), ","))
}
args = appendIfStringSet(args, "--shell", c.Shell)
args = append(args, c.Name)
_, err = u.LogCmd(exec.Command(cmd, args...),
"creating or modifying user %q", c.Name)
return err
}
// GetUserHomeDir returns the user home directory. Note that DestDir is not
// prefixed.
func (u Util) GetUserHomeDir(c types.PasswdUser) (string, error) {
usr, err := u.userLookup(c.Name)
if err != nil {
return "", err
}
return usr.HomeDir, nil
}
// CheckIfUserExists will return Info log when user is empty
func (u Util) CheckIfUserExists(c types.PasswdUser) (bool, error) {
_, err := u.userLookup(c.Name)
if _, ok := err.(user.UnknownUserError); ok {
return false, nil
}
if err != nil {
return false, err
}
return true, nil
}
// golang--
func translateV2_1PasswdUserGroupSliceToStringSlice(groups []types.Group) []string {
newGroups := make([]string, len(groups))
for i, g := range groups {
newGroups[i] = string(g)
}
return newGroups
}
// writeAuthKeysFile writes the content in keys to the path fp for the user,
// creating any directories in fp as needed.
func writeAuthKeysFile(u *user.User, fp string, keys []byte) error {
if err := as_user.MkdirAll(u, filepath.Dir(fp), 0700); err != nil {
return fmt.Errorf("creating parent dirs for %q: %w", fp, err)
}
f, err := as_user.OpenFile(u, fp, unix.O_WRONLY|unix.O_CREAT|unix.O_TRUNC, 0600)
if err != nil {
return fmt.Errorf("opening file %q as user %s and group %s: %w", fp, u.Uid, u.Gid, err)
}
if _, err = f.Write(keys); err != nil {
f.Close() // ignore errors
return fmt.Errorf("writing file %q: %w", fp, err)
}
if err := f.Close(); err != nil {
return fmt.Errorf("closing file %q: %w", fp, err)
}
return nil
}
// ModifyHomeDirPermissions changes the permissions for the user's home
// directory if it was created during the Ignition mount stage as a
// result of a mountpoint.
func (u Util) ModifyHomeDirPermissions(c types.PasswdUser) error {
if util.IsTrue(c.NoCreateHome) {
return nil
}
homeDir, err := u.GetUserHomeDir(c)
if err != nil {
return err
}
usr, err := u.userLookup(c.Name)
if err != nil {
return fmt.Errorf("unable to look up user %q: %w", c.Name, err)
}
uid, err := strconv.Atoi(usr.Uid)
if err != nil {
return fmt.Errorf("converting uid to int: %w", err)
}
gid, err := strconv.Atoi(usr.Gid)
if err != nil {
return fmt.Errorf("converting gid to int: %w", err)
}
for _, dir := range u.State.NotatedDirectories {
if dir == homeDir || strings.HasPrefix(dir, homeDir+"/") {
dir, err = u.JoinPath(dir)
if err != nil {
return fmt.Errorf("calculating path of %q: %w", dir, err)
}
if err := os.Chown(dir, uid, gid); err != nil {
return fmt.Errorf("changing ownership of %q: %w", dir, err)
}
// more restrictive than necessary for some subdirs,
// but default to secure
if err := os.Chmod(dir, 0700); err != nil {
return fmt.Errorf("changing file mode of %q: %w", dir, err)
}
}
}
return nil
}
// AuthorizeSSHKeys adds the provided SSH public keys to the user's authorized keys.
func (u Util) AuthorizeSSHKeys(c types.PasswdUser) error {
if len(c.SSHAuthorizedKeys) == 0 {
return nil
}
return u.LogOp(func() error {
usr, err := u.userLookup(c.Name)
if err != nil {
return fmt.Errorf("unable to lookup user %q", c.Name)
}
// TODO(vc): introduce key names to config?
// TODO(vc): validate c.SSHAuthorizedKeys well-formedness.
ks := strings.Join(translateV2_1SSHAuthorizedKeySliceToStringSlice(c.SSHAuthorizedKeys), "\n")
// XXX(vc): for now ensure the addition is always
// newline-terminated. A future version of akd will handle this
// for us in addition to validating the ssh keys for
// well-formedness.
if !strings.HasSuffix(ks, "\n") {
ks = ks + "\n"
}
var path string
if distro.WriteAuthorizedKeysFragment() {
path, err = u.JoinPath(usr.HomeDir, ".ssh", "authorized_keys.d", "ignition")
if err == nil {
err = writeAuthKeysFile(usr, path, []byte(ks))
}
} else {
path, err = u.JoinPath(usr.HomeDir, ".ssh", "authorized_keys")
if err == nil {
err = writeAuthKeysFile(usr, path, []byte(ks))
}
}
if err != nil {
return fmt.Errorf("failed to set SSH key: %v", err)
}
_ = journal.Send(fmt.Sprintf("wrote ssh authorized keys file for user: %s", c.Name), journal.PriInfo, map[string]string{
"IGNITION_USER_NAME": c.Name,
"IGNITION_PATH": path,
"MESSAGE_ID": ignitionSSHAuthorizedkeysMessageID,
})
return nil
}, "adding ssh keys to user %q", c.Name)
}
// golang--
func translateV2_1SSHAuthorizedKeySliceToStringSlice(keys []types.SSHAuthorizedKey) []string {
newKeys := make([]string, len(keys))
for i, k := range keys {
newKeys[i] = string(k)
}
return newKeys
}
// SetPasswordHash sets the password hash of the specified user.
func (u Util) SetPasswordHash(c types.PasswdUser) error {
if c.PasswordHash == nil {
return nil
}
pwhash := *c.PasswordHash
if *c.PasswordHash == "" {
pwhash = "*"
}
args := []string{
"--root", u.DestDir,
"--password", pwhash,
}
args = append(args, c.Name)
_, err := u.LogCmd(exec.Command(distro.UsermodCmd(), args...),
"setting password for %q", c.Name)
return err
}
// EnsureGroup ensures that the group exists as described. If the
// `shouldExist` field is set to false and the group already exists,
// then it will be deleted.
func (u Util) EnsureGroup(g types.PasswdGroup) error {
shouldExist := !util.IsFalse(g.ShouldExist)
exists, err := u.CheckIfGroupExists(g)
if err != nil {
return err
}
if !shouldExist {
if exists {
args := []string{"--root", u.DestDir, g.Name}
_, err := u.LogCmd(exec.Command(distro.GroupdelCmd(), args...),
"deleting group %q", g.Name)
if err != nil {
return fmt.Errorf("failed to delete group %q: %v",
g.Name, err)
}
}
return nil
}
args := []string{"--root", u.DestDir}
if g.Gid != nil {
args = append(args, "--gid",
strconv.FormatUint(uint64(*g.Gid), 10))
}
if util.NotEmpty(g.PasswordHash) {
args = append(args, "--password", *g.PasswordHash)
} else {
args = append(args, "--password", "*")
}
args = appendIfTrue(args, g.System, "--system")
args = append(args, g.Name)
_, err = u.LogCmd(exec.Command(distro.GroupaddCmd(), args...),
"adding group %q", g.Name)
return err
}
// CheckIfGroupExists will return Info log when group is empty
func (u Util) CheckIfGroupExists(g types.PasswdGroup) (bool, error) {
_, err := u.groupLookup(g.Name)
if _, ok := err.(user.UnknownGroupError); ok {
return false, nil
}
if err != nil {
return false, err
}
return true, nil
}