password tracking and changing in etc

4 files changed, 128 insertions, 24 deletions

diff --git a/src/parabola_hackers/.gitignore b/src/parabola_hackers/.gitignore
index e93884b..3be3f08 100644
--- a/src/parabola_hackers/.gitignore
+++ b/src/parabola_hackers/.gitignore
@@ -1 +1,2 @@
 /users.go
+/passwords.go
diff --git a/src/parabola_hackers/nslcd_backend/db_pam.go b/src/parabola_hackers/nslcd_backend/db_pam.go
index 303a66c..3374170 100644
--- a/src/parabola_hackers/nslcd_backend/db_pam.go
+++ b/src/parabola_hackers/nslcd_backend/db_pam.go
@@ -17,17 +17,32 @@
 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)
@@ -97,3 +112,56 @@ func (o *Hackers) PAM_SessionClose(cred s.Ucred, req p.Request_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/src/parabola_hackers/nslcd_backend/hackers.go b/src/parabola_hackers/nslcd_backend/hackers.go
index f7d56e3..bb03862 100644
--- a/src/parabola_hackers/nslcd_backend/hackers.go
+++ b/src/parabola_hackers/nslcd_backend/hackers.go
@@ -82,14 +82,19 @@ func (o *Hackers) Reload() error {
 		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
-		var _err error
-		user.Passwd.PwHash, _err = parabola_hackers.LoadUserPassword(user.Passwd.HomeDir + "/.password")
-		if _err != nil {
-			logger.Debug("hackers.git: Ignoring password: %v", _err)
+		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)
diff --git a/src/parabola_hackers/password.go b/src/parabola_hackers/passwords.go.in
index 957de1f..0d763b9 100644
--- a/src/parabola_hackers/password.go
+++ b/src/parabola_hackers/passwords.go.in
@@ -20,9 +20,11 @@ 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:
@@ -32,33 +34,61 @@ import (
              often used to indicate that the password is defined elsewhere
    other   - encrypted password, in crypt(3) format */
 
-func LoadUserPassword(filename string) (hash string, err error) {
-	file, err := os.Open(filename)
+const shadow_file = "@shadow_file@"
+
+func LoadAllPasswords() (map[string]string, error) {
+	file, err := os.Open(shadow_file)
 	if err != nil {
-		return
+		return nil, err
 	}
 	contents, err := ioutil.ReadAll(file)
 	if err != nil {
-		return
+		return nil, err
 	}
 	lines := strings.Split(string(contents), "\n")
-	switch len(lines) {
-	case 1:
-		hash = lines[0]
-	case 2:
-		if lines[1] == "" {
-			hash = lines[0]
-		} else {
-			err = fmt.Errorf("Invalid password format in file: %q", filename)
+	passwords := make(map[string]string, len(lines))
+	for i, line := range lines {
+		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)
 		}
-	default:
-		err = fmt.Errorf("Invalid password format in file (number of lines): %q", filename)
-		return
+		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])
 	}
-	if hash != "!" && !crypt.SaltOk(hash) {
-		hash = "!"
-		err = fmt.Errorf("Invalid password format in file (invalid salt): %q", filename)
-		return
+	err = file.Sync()
+	if err != nil {
+		return err
 	}
-	return
+	err = file.Close()
+	if err != nil {
+		return err
+	}
+
+	return os.Rename(shadow_file+"-", shadow_file)
 }