11 files changed, 975 insertions, 0 deletions
diff --git a/go/parabola_hackers/.gitignore b/go/parabola_hackers/.gitignore
new file mode 100644
index 0000000..3be3f08
--- /dev/null
+++ b/go/parabola_hackers/.gitignore
@@ -0,0 +1,2 @@
+/users.go
+/passwords.go
diff --git a/go/parabola_hackers/nslcd_backend/db_config.go b/go/parabola_hackers/nslcd_backend/db_config.go
new file mode 100644
index 0000000..e78643b
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/db_config.go
@@ -0,0 +1,40 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	s "syscall"
+
+	p "lukeshu.com/git/go/libnslcd.git/proto"
+)
+
+func (o *Hackers) Config_Get(cred s.Ucred, req p.Request_Config_Get) <-chan p.Config {
+	o.lock.RLock()
+	ret := make(chan p.Config)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		switch req.Key {
+		case p.NSLCD_CONFIG_PAM_PASSWORD_PROHIBIT_MESSAGE:
+			if o.cfg.Pam_password_prohibit_message != "" {
+				ret <- p.Config{Value: o.cfg.Pam_password_prohibit_message}
+			}
+		}
+	}()
+	return ret
+}
diff --git a/go/parabola_hackers/nslcd_backend/db_group.go b/go/parabola_hackers/nslcd_backend/db_group.go
new file mode 100644
index 0000000..18e54b1
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/db_group.go
@@ -0,0 +1,141 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	"parabola_hackers"
+	s "syscall"
+
+	p "lukeshu.com/git/go/libnslcd.git/proto"
+)
+
+func (o *Hackers) groupByName(name string, users bool) p.Group {
+	members_set, found := o.groups[name]
+	if !found {
+		return p.Group{ID: -1}
+	}
+	gid := name2gid(name)
+	if gid < 0 {
+		return p.Group{ID: -1}
+	}
+	var members_list []string
+	if users {
+		members_list = parabola_hackers.Set2list(members_set)
+	} else {
+		members_list = make([]string, 0)
+	}
+	return p.Group{
+		Name:    name,
+		PwHash:  "x",
+		ID:      gid,
+		Members: members_list,
+	}
+}
+
+func (o *Hackers) groupByGid(gid int32, users bool) p.Group {
+	name, found := gid2name(gid)
+	if !found {
+		return p.Group{ID: -1}
+	}
+	members_set, found := o.groups[name]
+	if !found {
+		return p.Group{ID: -1}
+	}
+	var members_list []string
+	if users {
+		members_list = parabola_hackers.Set2list(members_set)
+	} else {
+		members_list = make([]string, 0)
+	}
+	return p.Group{
+		Name:    name,
+		PwHash:  "x",
+		ID:      gid,
+		Members: members_list,
+	}
+}
+
+func (o *Hackers) Group_ByName(cred s.Ucred, req p.Request_Group_ByName) <-chan p.Group {
+	o.lock.RLock()
+	ret := make(chan p.Group)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		group := o.groupByName(req.Name, true)
+		if group.ID < 0 {
+			return
+		}
+		ret <- group
+	}()
+	return ret
+}
+
+func (o *Hackers) Group_ByGid(cred s.Ucred, req p.Request_Group_ByGid) <-chan p.Group {
+	o.lock.RLock()
+	ret := make(chan p.Group)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		group := o.groupByGid(req.Gid, true)
+		if group.ID < 0 {
+			return
+		}
+		ret <- group
+	}()
+	return ret
+}
+
+// note that the BYMEMBER call returns an empty members list
+func (o *Hackers) Group_ByMember(cred s.Ucred, req p.Request_Group_ByMember) <-chan p.Group {
+	o.lock.RLock()
+	ret := make(chan p.Group)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		uid := o.name2uid(req.Member)
+		if uid < 0 {
+			return
+		}
+		for _, name := range o.users[uid].Groups {
+			group := o.groupByName(name, false)
+			if group.ID >= 0 {
+				ret <- group
+			}
+		}
+	}()
+	return ret
+}
+
+func (o *Hackers) Group_All(cred s.Ucred, req p.Request_Group_All) <-chan p.Group {
+	o.lock.RLock()
+	ret := make(chan p.Group)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		for name, _ := range o.groups {
+			group := o.groupByName(name, true)
+			if group.ID >= 0 {
+				ret <- group
+			}
+		}
+	}()
+	return ret
+}
diff --git a/go/parabola_hackers/nslcd_backend/db_pam.go b/go/parabola_hackers/nslcd_backend/db_pam.go
new file mode 100644
index 0000000..3374170
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/db_pam.go
@@ -0,0 +1,167 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	"fmt"
+	"parabola_hackers"
+	s "syscall"
+
+	"lukeshu.com/git/go/libgnulinux.git/crypt"
+	p "lukeshu.com/git/go/libnslcd.git/proto"
+	"lukeshu.com/git/go/libsystemd.git/sd_daemon/logger"
+)
+
+func checkPassword(password string, hash string) bool {
+	return crypt.Crypt(password, hash) == hash
+}
+
+func hashPassword(newPassword string, oldHash string) string {
+	salt := oldHash
+	if salt == "!" {
+		str, err := parabola_hackers.RandomString(crypt.SaltAlphabet, 8)
+		if err != nil {
+			logger.Err("Could not generate a random string")
+			str = ""
+		}
+		salt = "$6$" + str + "$"
+	}
+	return crypt.Crypt(newPassword, salt)
+}
+
+func (o *Hackers) PAM_Authentication(cred s.Ucred, req p.Request_PAM_Authentication) <-chan p.PAM_Authentication {
+	o.lock.RLock()
+	ret := make(chan p.PAM_Authentication)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		uid := o.name2uid(req.UserName)
+		if uid < 0 {
+			return
+		}
+
+		user := o.users[uid]
+		obj := p.PAM_Authentication{
+			AuthenticationResult: p.NSLCD_PAM_AUTH_ERR,
+			UserName:             "",
+			AuthorizationResult:  p.NSLCD_PAM_AUTH_ERR,
+			AuthorizationError:   "",
+		}
+		if checkPassword(req.Password, user.Passwd.PwHash) {
+			obj.AuthenticationResult = p.NSLCD_PAM_SUCCESS
+			obj.AuthorizationResult = obj.AuthenticationResult
+			obj.UserName = user.Passwd.Name
+		}
+		ret <- obj
+	}()
+	return ret
+}
+
+func (o *Hackers) PAM_Authorization(cred s.Ucred, req p.Request_PAM_Authorization) <-chan p.PAM_Authorization {
+	o.lock.RLock()
+	ret := make(chan p.PAM_Authorization)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		uid := o.name2uid(req.UserName)
+		if uid < 0 {
+			return
+		}
+		ret <- p.PAM_Authorization{
+			Result: p.NSLCD_PAM_SUCCESS,
+			Error:  "",
+		}
+	}()
+	return ret
+}
+
+const alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+
+func (o *Hackers) PAM_SessionOpen(cred s.Ucred, req p.Request_PAM_SessionOpen) <-chan p.PAM_SessionOpen {
+	ret := make(chan p.PAM_SessionOpen)
+	go func() {
+		defer close(ret)
+
+		sessionid, err := parabola_hackers.RandomString(alphabet, 24)
+		if err != nil {
+			return
+		}
+		ret <- p.PAM_SessionOpen{SessionID: sessionid}
+	}()
+	return ret
+}
+
+func (o *Hackers) PAM_SessionClose(cred s.Ucred, req p.Request_PAM_SessionClose) <-chan p.PAM_SessionClose {
+	ret := make(chan p.PAM_SessionClose)
+	go close(ret)
+	return ret
+}
+
+func (o *Hackers) PAM_PwMod(cred s.Ucred, req p.Request_PAM_PwMod) <-chan p.PAM_PwMod {
+	ret := make(chan p.PAM_PwMod)
+	o.lock.Lock()
+	go func() {
+		defer close(ret)
+		defer o.lock.Unlock()
+
+		uid := o.name2uid(req.UserName)
+		if uid < 0 {
+			return
+		}
+		user := o.users[uid]
+
+		// Check the OldPassword
+		if req.AsRoot == 1 {
+			if !checkPassword(req.OldPassword, user.Passwd.PwHash) {
+				ret <- p.PAM_PwMod{
+					Result: p.NSLCD_PAM_PERM_DENIED,
+					Error:  fmt.Sprintf("password change failed: %s", "Old password did not match"),
+				}
+				return
+			}
+		}
+
+		// Update the PwHash in memory
+		user.Passwd.PwHash = hashPassword(req.NewPassword, user.Passwd.PwHash)
+		if user.Passwd.PwHash == "" {
+			logger.Err("Password hashing failed")
+			return
+		}
+
+		// Update the PwHash on disk
+		passwords := make(map[string]string, len(o.users))
+		for _, ouser := range o.users {
+			passwords[ouser.Passwd.Name] = ouser.Passwd.PwHash
+		}
+		passwords[user.Passwd.Name] = user.Passwd.PwHash
+		err := parabola_hackers.SaveAllPasswords(passwords)
+		if err != nil {
+			logger.Err("Writing passwords to disk: %v", err)
+			return
+		}
+
+		// Ok, we're done, commit the changes
+		o.users[uid] = user
+		ret <- p.PAM_PwMod{
+			Result: p.NSLCD_PAM_SUCCESS,
+			Error:  "",
+		}
+	}()
+	return ret
+}
diff --git a/go/parabola_hackers/nslcd_backend/db_passwd.go b/go/parabola_hackers/nslcd_backend/db_passwd.go
new file mode 100644
index 0000000..3f32ddd
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/db_passwd.go
@@ -0,0 +1,82 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	s "syscall"
+
+	p "lukeshu.com/git/go/libnslcd.git/proto"
+)
+
+/* Note that the output password hash value should be one of:
+   <empty> - no password set, allow login without password
+   !       - used to prevent logins
+   x       - "valid" encrypted password that does not match any valid password
+             often used to indicate that the password is defined elsewhere
+   other   - encrypted password, in crypt(3) format */
+
+func (o *Hackers) Passwd_ByName(cred s.Ucred, req p.Request_Passwd_ByName) <-chan p.Passwd {
+	o.lock.RLock()
+	ret := make(chan p.Passwd)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		uid := o.name2uid(req.Name)
+		if uid < 0 {
+			return
+		}
+		passwd := o.users[uid].Passwd
+		passwd.PwHash = "x" // only put actual hashes in the Shadow DB
+		ret <- passwd
+	}()
+	return ret
+}
+
+func (o *Hackers) Passwd_ByUID(cred s.Ucred, req p.Request_Passwd_ByUID) <-chan p.Passwd {
+	o.lock.RLock()
+	ret := make(chan p.Passwd)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		user, found := o.users[req.UID]
+		if !found {
+			return
+		}
+		passwd := user.Passwd
+		passwd.PwHash = "x" // only put actual hashes in the Shadow DB
+		ret <- passwd
+	}()
+	return ret
+}
+
+func (o *Hackers) Passwd_All(cred s.Ucred, req p.Request_Passwd_All) <-chan p.Passwd {
+	o.lock.RLock()
+	ret := make(chan p.Passwd)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		for _, user := range o.users {
+			passwd := user.Passwd
+			passwd.PwHash = "x" // only put actual hashes in the Shadow DB
+			ret <- passwd
+		}
+	}()
+	return ret
+}
diff --git a/go/parabola_hackers/nslcd_backend/db_shadow.go b/go/parabola_hackers/nslcd_backend/db_shadow.go
new file mode 100644
index 0000000..abfff28
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/db_shadow.go
@@ -0,0 +1,78 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	s "syscall"
+
+	p "lukeshu.com/git/go/libnslcd.git/proto"
+)
+
+func (o *Hackers) Shadow_ByName(cred s.Ucred, req p.Request_Shadow_ByName) <-chan p.Shadow {
+	o.lock.RLock()
+	ret := make(chan p.Shadow)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		if cred.Uid != 0 {
+			return
+		}
+		uid := o.name2uid(req.Name)
+		user := o.users[uid]
+		ret <- p.Shadow{
+			Name:           user.Passwd.Name,
+			PwHash:         user.Passwd.PwHash,
+			LastChangeDate: -1,
+			MinDays:        -1,
+			MaxDays:        -1,
+			WarnDays:       -1,
+			InactDays:      -1,
+			ExpireDate:     -1,
+			Flag:           -1,
+		}
+	}()
+	return ret
+}
+
+func (o *Hackers) Shadow_All(cred s.Ucred, req p.Request_Shadow_All) <-chan p.Shadow {
+	o.lock.RLock()
+	ret := make(chan p.Shadow)
+	go func() {
+		defer o.lock.RUnlock()
+		defer close(ret)
+
+		if cred.Uid != 0 {
+			return
+		}
+
+		for _, user := range o.users {
+			ret <- p.Shadow{
+				Name:           user.Passwd.Name,
+				PwHash:         user.Passwd.PwHash,
+				LastChangeDate: -1,
+				MinDays:        -1,
+				MaxDays:        -1,
+				WarnDays:       -1,
+				InactDays:      -1,
+				ExpireDate:     -1,
+				Flag:           -1,
+			}
+		}
+	}()
+	return ret
+}
diff --git a/go/parabola_hackers/nslcd_backend/hackers.go b/go/parabola_hackers/nslcd_backend/hackers.go
new file mode 100644
index 0000000..bb03862
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/hackers.go
@@ -0,0 +1,122 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+// Package hackers_nslcd_backend is an nslcd_server Backend that
+// speaks to hackers.git.
+package hackers_nslcd_backend
+
+import (
+	"parabola_hackers"
+	"sync"
+
+	nslcd_server "lukeshu.com/git/go/libnslcd.git/proto/server"
+	nslcd_systemd "lukeshu.com/git/go/libnslcd.git/systemd"
+	"lukeshu.com/git/go/libsystemd.git/sd_daemon/logger"
+)
+
+type config struct {
+	Pam_password_prohibit_message string
+}
+
+type Hackers struct {
+	nslcd_server.NilBackend
+	lock sync.RWMutex
+
+	CfgFilename string
+
+	cfg    config
+	users  map[int32]parabola_hackers.User
+	groups map[string]map[string]bool
+}
+
+var _ nslcd_systemd.Backend = &Hackers{}
+var _ nslcd_server.Backend = &Hackers{}
+
+func (o *Hackers) Init() error {
+	logger.Debug("hackers.git: CfgFilename = %v", o.CfgFilename)
+	err := o.Reload()
+	if err != nil {
+		logger.Err("hackers.git: Could not initialize: %v", err)
+		return err
+	}
+	return nil
+}
+
+func (o *Hackers) Close() {
+	logger.Info("hackers.git: Closing session")
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
+	o.users = make(map[int32]parabola_hackers.User, 0)
+	o.groups = make(map[string]map[string]bool)
+}
+
+func (o *Hackers) Reload() error {
+	logger.Info("hackers.git: Loading session")
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
+	var err error
+	o.cfg, err = parse_config(o.CfgFilename)
+	if err != nil {
+		return err
+	}
+	logger.Info("hackers.git: pam_password_prohibit_message: %#v", o.cfg.Pam_password_prohibit_message)
+
+	logger.Debug("hackers.git:  Parsing user data")
+	o.users, err = parabola_hackers.LoadAllUsers()
+	if err != nil {
+		return err
+	}
+
+	passwords, err := parabola_hackers.LoadAllPasswords()
+	if err != nil {
+		return err
+	}
+
+	o.groups = make(map[string]map[string]bool)
+	for uid, user := range o.users {
+		user.Passwd.GID = usersGid
+		hash, hasHash := passwords[user.Passwd.Name]
+		if !hasHash {
+			hash = "!"
+		}
+		user.Passwd.PwHash = hash
+		o.users[uid] = user
+		for _, groupname := range user.Groups {
+			o.add_user_to_group(user.Passwd.Name, groupname)
+		}
+	}
+	return nil
+}
+
+func (o *Hackers) name2uid(name string) int32 {
+	for uid, data := range o.users {
+		if data.Passwd.Name == name {
+			return uid
+		}
+	}
+	return -1
+}
+
+func (o *Hackers) add_user_to_group(username string, groupname string) {
+	group, found := o.groups[groupname]
+	if !found {
+		group = make(map[string]bool)
+		o.groups[groupname] = group
+	}
+	group[username] = true
+}
diff --git a/go/parabola_hackers/nslcd_backend/util.go b/go/parabola_hackers/nslcd_backend/util.go
new file mode 100644
index 0000000..4fb28f3
--- /dev/null
+++ b/go/parabola_hackers/nslcd_backend/util.go
@@ -0,0 +1,58 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package hackers_nslcd_backend
+
+import (
+	"io/ioutil"
+	"os"
+
+	yaml "gopkg.in/yaml.v2"
+	"lukeshu.com/git/go/libgnulinux.git/getgr"
+)
+
+func name2gid(name string) int32 {
+	gr, err := getgr.ByName(name)
+	if gr == nil || err != nil {
+		return -1
+	} else {
+		return int32(gr.Gid)
+	}
+}
+
+func gid2name(gid int32) (string, bool) {
+	gr, err := getgr.ByGid(gid)
+	if gr == nil || err != nil {
+		return "", false
+	} else {
+		return gr.Name, true
+	}
+}
+
+var usersGid = name2gid("users")
+
+func parse_config(filename string) (cfg config, err error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	contents, err := ioutil.ReadAll(file)
+	if err != nil {
+		return
+	}
+	err = yaml.Unmarshal(contents, &cfg)
+	return
+}
diff --git a/go/parabola_hackers/passwords.go.in b/go/parabola_hackers/passwords.go.in
new file mode 100644
index 0000000..b9f93d9
--- /dev/null
+++ b/go/parabola_hackers/passwords.go.in
@@ -0,0 +1,97 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package parabola_hackers
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"sort"
+	"strings"
+
+	"lukeshu.com/git/go/libgnulinux.git/crypt"
+	"lukeshu.com/git/go/libsystemd.git/sd_daemon/logger"
+)
+
+/* Note that the password hash value should be one of:
+   <empty> - no password set, allow login without password
+   !       - used to prevent logins
+   x       - "valid" encrypted password that does not match any valid password
+             often used to indicate that the password is defined elsewhere
+   other   - encrypted password, in crypt(3) format */
+
+const shadow_file = "@shadow_file@"
+
+func LoadAllPasswords() (map[string]string, error) {
+	file, err := os.Open(shadow_file)
+	if err != nil {
+		return nil, err
+	}
+	contents, err := ioutil.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+	lines := strings.Split(string(contents), "\n")
+	passwords := make(map[string]string, len(lines))
+	for i, line := range lines {
+		if line == "" {
+			continue
+		}
+		cols := strings.SplitN(line, ":", 2)
+		if len(cols) != 2 {
+			logger.Err("hackers.git %s:%d: malformed line", shadow_file, i+1)
+			continue
+		}
+		username := cols[0]
+		hash := cols[1]
+		if hash != "!" && !crypt.SaltOk(hash) {
+			hash = "!"
+			logger.Err("%s:%d: malformed hash for user: %s", shadow_file, i+1, username)
+		}
+		passwords[username] = hash
+	}
+	return passwords, nil
+}
+
+func SaveAllPasswords(passwords map[string]string) error {
+	usernames := make([]string, len(passwords))
+	i := 0
+	for username, _ := range passwords {
+		usernames[i] = username
+		i++
+	}
+	sort.Strings(usernames)
+
+	file, err := os.OpenFile(shadow_file+"-", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+
+	for _, username := range usernames {
+		fmt.Fprintf(file, "%s:%s\n", username, passwords[username])
+	}
+	err = file.Sync()
+	if err != nil {
+		return err
+	}
+	err = file.Close()
+	if err != nil {
+		return err
+	}
+
+	return os.Rename(shadow_file+"-", shadow_file)
+}
diff --git a/go/parabola_hackers/users.go.in b/go/parabola_hackers/users.go.in
new file mode 100644
index 0000000..aeda069
--- /dev/null
+++ b/go/parabola_hackers/users.go.in
@@ -0,0 +1,141 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package parabola_hackers
+
+import (
+	"fmt"
+	"os/exec"
+
+	yaml "gopkg.in/yaml.v2"
+	nslcd_proto "lukeshu.com/git/go/libnslcd.git/proto"
+	"lukeshu.com/git/go/libsystemd.git/sd_daemon/logger"
+)
+
+/* Note that the password hash value should be one of:
+   <empty> - no password set, allow login without password
+   !       - used to prevent logins
+   x       - "valid" encrypted password that does not match any valid password
+             often used to indicate that the password is defined elsewhere
+   other   - encrypted password, in crypt(3) format */
+
+type User struct {
+	Passwd nslcd_proto.Passwd
+	Groups []string
+}
+
+func LoadAllUsers() (users map[int32]User, err error) {
+	contents, err := exec.Command("@bindir@/meta-cat").Output()
+	if err != nil {
+		return
+	}
+
+	var _data interface{}
+	err = yaml.Unmarshal(contents, &_data)
+	if err != nil {
+		return
+	}
+
+	data, isMap := _data.(map[interface{}]interface{})
+	errs := []string{}
+	if !isMap {
+		errs = append(errs, "root node is not a map")
+	} else {
+		users = make(map[int32]User, len(data))
+		for _uid, _user := range data {
+			uid, isInt := _uid.(int)
+			if !isInt {
+				errs = append(errs, fmt.Sprintf("UID is not an int: %T ( %#v )", _uid, _uid))
+				continue
+			}
+			user, _err := parseUser(_user)
+			if _err != nil {
+				errs = append(errs, fmt.Sprintf("Could not parse data for UID %d: %v", uid, _err))
+				continue
+			}
+			user.Passwd.UID = int32(uid)
+			logger.Debug("hackers.git:  -> User %d(%s) parsed", user.Passwd.UID, user.Passwd.Name)
+			users[user.Passwd.UID] = user
+		}
+	}
+	if len(errs) > 0 {
+		users = nil
+		err = &yaml.TypeError{Errors: errs}
+	}
+	return
+}
+
+func parseUser(_data interface{}) (ret User, err error) {
+	data, isMap := _data.(map[interface{}]interface{})
+	errs := []string{}
+	if !isMap {
+		errs = append(errs, "root node is not a map")
+	} else {
+		if iface, isSet := data["username"]; !isSet {
+			errs = append(errs, "\"username\" is not set")
+		} else if str, isTyp := iface.(string); !isTyp {
+			errs = append(errs, "\"username\" is not a string")
+		} else {
+			ret.Passwd.Name = str
+			ret.Passwd.HomeDir = "/home/" + str
+		}
+
+		if iface, isSet := data["fullname"]; !isSet {
+			errs = append(errs, "\"fullname\" is not set")
+		} else if str, isTyp := iface.(string); !isTyp {
+			errs = append(errs, "\"fullname\" is not a string")
+		} else {
+			ret.Passwd.GECOS = str
+		}
+
+		if iface, isSet := data["shell"]; !isSet {
+			errs = append(errs, "\"shell\" is not set")
+		} else if str, isTyp := iface.(string); !isTyp {
+			errs = append(errs, "\"shell\" is not a string")
+		} else {
+			ret.Passwd.Shell = str
+		}
+
+		if iface, isSet := data["groups"]; !isSet {
+			ret.Groups = make([]string, 0)
+		} else if ary, isTyp := iface.([]interface{}); !isTyp {
+			errs = append(errs, "\"groups\" is not an array")
+		} else {
+			groups := make(map[string]bool, len(ary))
+			e := false
+			for _, iface := range ary {
+				if str, isTyp := iface.(string); !isTyp {
+					errs = append(errs, "\"group\" item is not an array")
+					e = true
+					break
+				} else {
+					groups[str] = true
+				}
+			}
+			if !e {
+				ret.Groups = Set2list(groups)
+			}
+		}
+	}
+	if len(errs) > 0 {
+		err = &yaml.TypeError{Errors: errs}
+	}
+
+	ret.Passwd.PwHash = "x" // look in shadow for the password hash
+	ret.Passwd.GID = -1
+
+	return
+}
diff --git a/go/parabola_hackers/util.go b/go/parabola_hackers/util.go
new file mode 100644
index 0000000..9a241db
--- /dev/null
+++ b/go/parabola_hackers/util.go
@@ -0,0 +1,47 @@
+// Copyright 2015-2016 Luke Shumaker <lukeshu@sbcglobal.net>.
+//
+// This is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// This software is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public
+// License along with this manual; if not, see
+// <http://www.gnu.org/licenses/>.
+
+package parabola_hackers
+
+import (
+	"crypto/rand"
+	"math/big"
+)
+
+func RandomString(alphabet string, n uint) (str string, err error) {
+	var alphabet_len = big.NewInt(int64(len(alphabet)))
+	var bigint *big.Int
+	_str := make([]byte, n)
+	for i := 0; i < len(_str); i++ {
+		bigint, err = rand.Int(rand.Reader, alphabet_len)
+		if err != nil {
+			return
+		}
+		_str[i] = alphabet[bigint.Int64()]
+	}
+	str = string(_str[:])
+	return
+}
+
+func Set2list(set map[string]bool) []string {
+	list := make([]string, len(set))
+	i := uint(0)
+	for item, _ := range set {
+		list[i] = item
+		i++
+	}
+	return list
+}