ntfy/auth/auth_sqlite.go
2022-02-01 16:40:33 -05:00

399 lines
11 KiB
Go

package auth
import (
"database/sql"
"errors"
"fmt"
_ "github.com/mattn/go-sqlite3" // SQLite driver
"golang.org/x/crypto/bcrypt"
"strings"
)
const (
bcryptCost = 11
intentionalSlowDownHash = "$2a$11$eX15DeF27FwAgXt9wqJF0uAUMz74XywJcGBH3kP93pzKYv6ATk2ka" // Cost should match bcryptCost
)
// Auther-related queries
const (
createAuthTablesQueries = `
BEGIN;
CREATE TABLE IF NOT EXISTS user (
user TEXT NOT NULL PRIMARY KEY,
pass TEXT NOT NULL,
role TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS access (
user TEXT NOT NULL,
topic TEXT NOT NULL,
read INT NOT NULL,
write INT NOT NULL,
PRIMARY KEY (topic, user)
);
CREATE TABLE IF NOT EXISTS schemaVersion (
id INT PRIMARY KEY,
version INT NOT NULL
);
COMMIT;
`
selectUserQuery = `SELECT pass, role FROM user WHERE user = ?`
selectTopicPermsQuery = `
SELECT read, write
FROM access
WHERE user IN ('*', ?) AND ? LIKE topic
ORDER BY user DESC
`
)
// Manager-related queries
const (
insertUserQuery = `INSERT INTO user (user, pass, role) VALUES (?, ?, ?)`
selectUsernamesQuery = `SELECT user FROM user ORDER BY role, user`
updateUserPassQuery = `UPDATE user SET pass = ? WHERE user = ?`
updateUserRoleQuery = `UPDATE user SET role = ? WHERE user = ?`
deleteUserQuery = `DELETE FROM user WHERE user = ?`
upsertUserAccessQuery = `
INSERT INTO access (user, topic, read, write)
VALUES (?, ?, ?, ?)
ON CONFLICT (user, topic) DO UPDATE SET read=excluded.read, write=excluded.write
`
selectUserAccessQuery = `SELECT topic, read, write FROM access WHERE user = ?`
deleteAllAccessQuery = `DELETE FROM access`
deleteUserAccessQuery = `DELETE FROM access WHERE user = ?`
deleteTopicAccessQuery = `DELETE FROM access WHERE user = ? AND topic = ?`
)
// Schema management queries
const (
currentSchemaVersion = 1
insertSchemaVersion = `INSERT INTO schemaVersion VALUES (1, ?)`
selectSchemaVersionQuery = `SELECT version FROM schemaVersion WHERE id = 1`
)
// SQLiteAuth is an implementation of Auther and Manager. It stores users and access control list
// in a SQLite database.
type SQLiteAuth struct {
db *sql.DB
defaultRead bool
defaultWrite bool
}
var _ Auther = (*SQLiteAuth)(nil)
var _ Manager = (*SQLiteAuth)(nil)
// NewSQLiteAuth creates a new SQLiteAuth instance
func NewSQLiteAuth(filename string, defaultRead, defaultWrite bool) (*SQLiteAuth, error) {
db, err := sql.Open("sqlite3", filename)
if err != nil {
return nil, err
}
if err := setupAuthDB(db); err != nil {
return nil, err
}
return &SQLiteAuth{
db: db,
defaultRead: defaultRead,
defaultWrite: defaultWrite,
}, nil
}
// Authenticate checks username and password and returns a user if correct. The method
// returns in constant-ish time, regardless of whether the user exists or the password is
// correct or incorrect.
func (a *SQLiteAuth) Authenticate(username, password string) (*User, error) {
if username == Everyone {
return nil, ErrUnauthenticated
}
user, err := a.User(username)
if err != nil {
bcrypt.CompareHashAndPassword([]byte(intentionalSlowDownHash),
[]byte("intentional slow-down to avoid timing attacks"))
return nil, ErrUnauthenticated
}
if err := bcrypt.CompareHashAndPassword([]byte(user.Hash), []byte(password)); err != nil {
return nil, ErrUnauthenticated
}
return user, nil
}
// Authorize returns nil if the given user has access to the given topic using the desired
// permission. The user param may be nil to signal an anonymous user.
func (a *SQLiteAuth) Authorize(user *User, topic string, perm Permission) error {
if user != nil && user.Role == RoleAdmin {
return nil // Admin can do everything
}
username := Everyone
if user != nil {
username = user.Name
}
// Select the read/write permissions for this user/topic combo. The query may return two
// rows (one for everyone, and one for the user), but prioritizes the user. The value for
// user.Name may be empty (= everyone).
rows, err := a.db.Query(selectTopicPermsQuery, username, topic)
if err != nil {
return err
}
defer rows.Close()
if !rows.Next() {
return a.resolvePerms(a.defaultRead, a.defaultWrite, perm)
}
var read, write bool
if err := rows.Scan(&read, &write); err != nil {
return err
} else if err := rows.Err(); err != nil {
return err
}
return a.resolvePerms(read, write, perm)
}
func (a *SQLiteAuth) resolvePerms(read, write bool, perm Permission) error {
if perm == PermissionRead && read {
return nil
} else if perm == PermissionWrite && write {
return nil
}
return ErrUnauthorized
}
// AddUser adds a user with the given username, password and role. The password should be hashed
// before it is stored in a persistence layer.
func (a *SQLiteAuth) AddUser(username, password string, role Role) error {
if !AllowedUsername(username) || !AllowedRole(role) {
return ErrInvalidArgument
}
hash, err := bcrypt.GenerateFromPassword([]byte(password), bcryptCost)
if err != nil {
return err
}
if _, err = a.db.Exec(insertUserQuery, username, hash, role); err != nil {
return err
}
return nil
}
// RemoveUser deletes the user with the given username. The function returns nil on success, even
// if the user did not exist in the first place.
func (a *SQLiteAuth) RemoveUser(username string) error {
if !AllowedUsername(username) {
return ErrInvalidArgument
}
if _, err := a.db.Exec(deleteUserQuery, username); err != nil {
return err
}
if _, err := a.db.Exec(deleteUserAccessQuery, username); err != nil {
return err
}
return nil
}
// Users returns a list of users. It always also returns the Everyone user ("*").
func (a *SQLiteAuth) Users() ([]*User, error) {
rows, err := a.db.Query(selectUsernamesQuery)
if err != nil {
return nil, err
}
defer rows.Close()
usernames := make([]string, 0)
for rows.Next() {
var username string
if err := rows.Scan(&username); err != nil {
return nil, err
} else if err := rows.Err(); err != nil {
return nil, err
}
usernames = append(usernames, username)
}
rows.Close()
users := make([]*User, 0)
for _, username := range usernames {
user, err := a.User(username)
if err != nil {
return nil, err
}
users = append(users, user)
}
everyone, err := a.everyoneUser()
if err != nil {
return nil, err
}
users = append(users, everyone)
return users, nil
}
// User returns the user with the given username if it exists, or ErrNotFound otherwise.
// You may also pass Everyone to retrieve the anonymous user and its Grant list.
func (a *SQLiteAuth) User(username string) (*User, error) {
if username == Everyone {
return a.everyoneUser()
}
rows, err := a.db.Query(selectUserQuery, username)
if err != nil {
return nil, err
}
defer rows.Close()
var hash, role string
if !rows.Next() {
return nil, ErrNotFound
}
if err := rows.Scan(&hash, &role); err != nil {
return nil, err
} else if err := rows.Err(); err != nil {
return nil, err
}
grants, err := a.readGrants(username)
if err != nil {
return nil, err
}
return &User{
Name: username,
Hash: hash,
Role: Role(role),
Grants: grants,
}, nil
}
func (a *SQLiteAuth) everyoneUser() (*User, error) {
grants, err := a.readGrants(Everyone)
if err != nil {
return nil, err
}
return &User{
Name: Everyone,
Hash: "",
Role: RoleAnonymous,
Grants: grants,
}, nil
}
func (a *SQLiteAuth) readGrants(username string) ([]Grant, error) {
rows, err := a.db.Query(selectUserAccessQuery, username)
if err != nil {
return nil, err
}
defer rows.Close()
grants := make([]Grant, 0)
for rows.Next() {
var topic string
var read, write bool
if err := rows.Scan(&topic, &read, &write); err != nil {
return nil, err
} else if err := rows.Err(); err != nil {
return nil, err
}
grants = append(grants, Grant{
TopicPattern: fromSQLWildcard(topic),
AllowRead: read,
AllowWrite: write,
})
}
return grants, nil
}
// ChangePassword changes a user's password
func (a *SQLiteAuth) ChangePassword(username, password string) error {
hash, err := bcrypt.GenerateFromPassword([]byte(password), bcryptCost)
if err != nil {
return err
}
if _, err := a.db.Exec(updateUserPassQuery, hash, username); err != nil {
return err
}
return nil
}
// ChangeRole changes a user's role. When a role is changed from RoleUser to RoleAdmin,
// all existing access control entries (Grant) are removed, since they are no longer needed.
func (a *SQLiteAuth) ChangeRole(username string, role Role) error {
if !AllowedUsername(username) || !AllowedRole(role) {
return ErrInvalidArgument
}
if _, err := a.db.Exec(updateUserRoleQuery, string(role), username); err != nil {
return err
}
if role == RoleAdmin {
if _, err := a.db.Exec(deleteUserAccessQuery, username); err != nil {
return err
}
}
return nil
}
// AllowAccess adds or updates an entry in th access control list for a specific user. It controls
// read/write access to a topic. The parameter topicPattern may include wildcards (*).
func (a *SQLiteAuth) AllowAccess(username string, topicPattern string, read bool, write bool) error {
if (!AllowedUsername(username) && username != Everyone) || !AllowedTopicPattern(topicPattern) {
return ErrInvalidArgument
}
if _, err := a.db.Exec(upsertUserAccessQuery, username, toSQLWildcard(topicPattern), read, write); err != nil {
return err
}
return nil
}
// ResetAccess removes an access control list entry for a specific username/topic, or (if topic is
// empty) for an entire user. The parameter topicPattern may include wildcards (*).
func (a *SQLiteAuth) ResetAccess(username string, topicPattern string) error {
if !AllowedUsername(username) && username != Everyone && username != "" {
return ErrInvalidArgument
} else if !AllowedTopicPattern(topicPattern) && topicPattern != "" {
return ErrInvalidArgument
}
if username == "" && topicPattern == "" {
_, err := a.db.Exec(deleteAllAccessQuery, username)
return err
} else if topicPattern == "" {
_, err := a.db.Exec(deleteUserAccessQuery, username)
return err
}
_, err := a.db.Exec(deleteTopicAccessQuery, username, toSQLWildcard(topicPattern))
return err
}
// DefaultAccess returns the default read/write access if no access control entry matches
func (a *SQLiteAuth) DefaultAccess() (read bool, write bool) {
return a.defaultRead, a.defaultWrite
}
func toSQLWildcard(s string) string {
return strings.ReplaceAll(s, "*", "%")
}
func fromSQLWildcard(s string) string {
return strings.ReplaceAll(s, "%", "*")
}
func setupAuthDB(db *sql.DB) error {
// If 'schemaVersion' table does not exist, this must be a new database
rowsSV, err := db.Query(selectSchemaVersionQuery)
if err != nil {
return setupNewAuthDB(db)
}
defer rowsSV.Close()
// If 'schemaVersion' table exists, read version and potentially upgrade
schemaVersion := 0
if !rowsSV.Next() {
return errors.New("cannot determine schema version: database file may be corrupt")
}
if err := rowsSV.Scan(&schemaVersion); err != nil {
return err
}
rowsSV.Close()
// Do migrations
if schemaVersion == currentSchemaVersion {
return nil
}
return fmt.Errorf("unexpected schema version found: %d", schemaVersion)
}
func setupNewAuthDB(db *sql.DB) error {
if _, err := db.Exec(createAuthTablesQueries); err != nil {
return err
}
if _, err := db.Exec(insertSchemaVersion, currentSchemaVersion); err != nil {
return err
}
return nil
}