1 5e70998a 2022-04-12 o package mailmux
  2 5e70998a 2022-04-12 o 
  3 5e70998a 2022-04-12 o import (
  4 5e70998a 2022-04-12 o 	"database/sql"
  5 5e70998a 2022-04-12 o 	"errors"
  6 5e70998a 2022-04-12 o 	"fmt"
  7 7583dd64 2022-04-13 o 	"net/mail"
  8 8d82f4f7 2022-04-12 o 	"os"
  9 8d82f4f7 2022-04-12 o 	"path"
 10 5e70998a 2022-04-12 o 
 11 5e70998a 2022-04-12 o 	_ "github.com/mattn/go-sqlite3"
 12 7583dd64 2022-04-13 o 	"golang.org/x/crypto/bcrypt"
 13 5e70998a 2022-04-12 o )
 14 5e70998a 2022-04-12 o 
 15 acca18c6 2022-04-23 o // maxUsernameSize defines a reasonable maximum length for an email address.
 16 acca18c6 2022-04-23 o const maxUsernameLength = 255
 17 acca18c6 2022-04-23 o 
 18 5e70998a 2022-04-12 o // UserDB is an implementation of UserStore backed by a SQLite3 database.
 19 5e70998a 2022-04-12 o // Users are fully authenticated after confirming ownership of their
 20 5e70998a 2022-04-12 o // email address by supplying a matching ticket to a generated ticket file.
 21 5e70998a 2022-04-12 o type UserDB struct {
 22 5e70998a 2022-04-12 o 	*sql.DB
 23 5e70998a 2022-04-12 o 	TicketDir string
 24 5e70998a 2022-04-12 o }
 25 5e70998a 2022-04-12 o 
 26 7583dd64 2022-04-13 o // CreateUserDB creates the named user database file and ticket directory.
 27 7583dd64 2022-04-13 o // If the database file already exists, it is truncated. If successfullly created,
 28 7583dd64 2022-04-13 o // the database's tables are initialised so the database is ready to use.
 29 7583dd64 2022-04-13 o func CreateUserDB(name, ticketDir string) (*UserDB, error) {
 30 7583dd64 2022-04-13 o 	_, err := os.Create(name)
 31 7583dd64 2022-04-13 o 	if err != nil {
 32 7583dd64 2022-04-13 o 		return nil, err
 33 7583dd64 2022-04-13 o 	}
 34 7583dd64 2022-04-13 o 	if err := os.MkdirAll(ticketDir, 0666); err != nil {
 35 7583dd64 2022-04-13 o 		return nil, fmt.Errorf("create user db: %w", err)
 36 7583dd64 2022-04-13 o 	}
 37 7583dd64 2022-04-13 o 	db, err := OpenUserDB(name, ticketDir)
 38 7583dd64 2022-04-13 o 	if err != nil {
 39 7583dd64 2022-04-13 o 		return nil, fmt.Errorf("create user db: %w", err)
 40 7583dd64 2022-04-13 o 	}
 41 be20893f 2022-04-25 o 	return db, initialiseUserDB(db.DB)
 42 7583dd64 2022-04-13 o }
 43 7583dd64 2022-04-13 o 
 44 5e70998a 2022-04-12 o // OpenUserDB opens the named user database file and ticket directory.
 45 a039d5d3 2022-05-12 o // If the database does not exist, it is created and its tables are
 46 be20893f 2022-04-25 o // initialised ready for use.
 47 5e70998a 2022-04-12 o func OpenUserDB(name, dir string) (*UserDB, error) {
 48 5e70998a 2022-04-12 o 	db, err := sql.Open("sqlite3", name)
 49 5e70998a 2022-04-12 o 	if err != nil {
 50 5e70998a 2022-04-12 o 		return nil, err
 51 5e70998a 2022-04-12 o 	}
 52 be20893f 2022-04-25 o 	if err := initialiseUserDB(db); err != nil {
 53 925168e0 2022-04-14 o 		return nil, err
 54 925168e0 2022-04-14 o 	}
 55 5e70998a 2022-04-12 o 	return &UserDB{db, dir}, db.Ping()
 56 5e70998a 2022-04-12 o }
 57 5e70998a 2022-04-12 o 
 58 be20893f 2022-04-25 o func initialiseUserDB(db *sql.DB) error {
 59 7583dd64 2022-04-13 o 	stmt := `CREATE TABLE IF NOT EXISTS users (
 60 7583dd64 2022-04-13 o 	username TEXT PRIMARY KEY,
 61 f7343271 2022-04-25 o 	password BLOB NOT NULL,
 62 e2ab3f7c 2022-04-25 o 	modtime INTEGER NOT NULL DEFAULT (unixepoch())
 63 7583dd64 2022-04-13 o );`
 64 7583dd64 2022-04-13 o 	_, err := db.Exec(stmt)
 65 7583dd64 2022-04-13 o 	return err
 66 7583dd64 2022-04-13 o }
 67 7583dd64 2022-04-13 o 
 68 5e70998a 2022-04-12 o func (db *UserDB) Lookup(name string) (User, error) {
 69 5e70998a 2022-04-12 o 	var u User
 70 5e70998a 2022-04-12 o 	row := db.QueryRow("SELECT username, password FROM users WHERE username = ?", name)
 71 5f060a33 2022-07-04 o 	var passwd string
 72 5f060a33 2022-07-04 o 	if err := row.Scan(&u.name, &passwd); err != nil {
 73 5e70998a 2022-04-12 o 		if errors.Is(err, sql.ErrNoRows) {
 74 71bdede3 2022-04-21 o 			return User{}, ErrUnknownUser
 75 5e70998a 2022-04-12 o 		}
 76 71bdede3 2022-04-21 o 		return User{}, err
 77 5e70998a 2022-04-12 o 	}
 78 5f060a33 2022-07-04 o 	u.password = Password(passwd)
 79 5e70998a 2022-04-12 o 	return u, nil
 80 5e70998a 2022-04-12 o }
 81 5e70998a 2022-04-12 o 
 82 5e70998a 2022-04-12 o func (db *UserDB) add(username string, pw Password) error {
 83 acca18c6 2022-04-23 o 	if len(username) > maxUsernameLength {
 84 a039d5d3 2022-05-12 o 		return fmt.Errorf("add %s: bad username: too long", username)
 85 acca18c6 2022-04-23 o 	}
 86 7583dd64 2022-04-13 o 	addr, err := mail.ParseAddress(username)
 87 5e70998a 2022-04-12 o 	if err != nil {
 88 a039d5d3 2022-05-12 o 		return fmt.Errorf("add %s: bad username: %w", username, err)
 89 7583dd64 2022-04-13 o 	}
 90 7583dd64 2022-04-13 o 	if addr.Name != "" {
 91 a039d5d3 2022-05-12 o 		return fmt.Errorf("add %s: bad username: proper name present", username)
 92 7583dd64 2022-04-13 o 	}
 93 7583dd64 2022-04-13 o 
 94 7583dd64 2022-04-13 o 	hashed, err := bcrypt.GenerateFromPassword(pw, bcrypt.DefaultCost)
 95 7583dd64 2022-04-13 o 	if err != nil {
 96 5e70998a 2022-04-12 o 		return fmt.Errorf("add %s: %w", username, err)
 97 5e70998a 2022-04-12 o 	}
 98 e2ab3f7c 2022-04-25 o 	_, err = db.Exec("INSERT INTO users (username, password) VALUES (?, ?)", username, hashed)
 99 7583dd64 2022-04-13 o 	if err != nil {
100 7583dd64 2022-04-13 o 		return fmt.Errorf("add %s: %w", username, err)
101 7583dd64 2022-04-13 o 	}
102 5e70998a 2022-04-12 o 	if err := createTicket(db.TicketDir, username, pw); err != nil {
103 5e70998a 2022-04-12 o 		return fmt.Errorf("add %s: create ticket: %w", username, err)
104 5e70998a 2022-04-12 o 	}
105 5e70998a 2022-04-12 o 	return nil
106 5e70998a 2022-04-12 o }
107 5e70998a 2022-04-12 o 
108 5e70998a 2022-04-12 o func (db *UserDB) Change(name string, new Password) error {
109 5e70998a 2022-04-12 o 	_, err := db.Lookup(name)
110 5e70998a 2022-04-12 o 	if errors.Is(err, ErrUnknownUser) {
111 5e70998a 2022-04-12 o 		return db.add(name, new)
112 5e70998a 2022-04-12 o 	}
113 5e70998a 2022-04-12 o 	if err != nil {
114 71bdede3 2022-04-21 o 		return fmt.Errorf("lookup %s: %w", name, err)
115 5e70998a 2022-04-12 o 	}
116 5e70998a 2022-04-12 o 
117 7583dd64 2022-04-13 o 	hashed, err := bcrypt.GenerateFromPassword(new, bcrypt.DefaultCost)
118 5e70998a 2022-04-12 o 	if err != nil {
119 71bdede3 2022-04-21 o 		return fmt.Errorf("generate hash: %w", err)
120 5e70998a 2022-04-12 o 	}
121 e2ab3f7c 2022-04-25 o 	q := "UPDATE users SET password = ?, modtime = unixepoch() WHERE username = ?"
122 e2ab3f7c 2022-04-25 o 	_, err = db.Exec(q, hashed, name)
123 71bdede3 2022-04-21 o 	return err
124 5e70998a 2022-04-12 o }
125 5e70998a 2022-04-12 o 
126 5e70998a 2022-04-12 o func (db *UserDB) Delete(name string) error {
127 5e70998a 2022-04-12 o 	_, err := db.Lookup(name)
128 5e70998a 2022-04-12 o 	if err != nil {
129 5e70998a 2022-04-12 o 		return fmt.Errorf("delete %s: %w", name, err)
130 5e70998a 2022-04-12 o 	}
131 5e70998a 2022-04-12 o 	_, err = db.Exec("DELETE FROM users WHERE username = ?", name)
132 5e70998a 2022-04-12 o 	if err != nil {
133 5e70998a 2022-04-12 o 		return fmt.Errorf("delete %s: %w", name, err)
134 5e70998a 2022-04-12 o 	}
135 5e70998a 2022-04-12 o 	return nil
136 5e70998a 2022-04-12 o }
137 8d82f4f7 2022-04-12 o 
138 7583dd64 2022-04-13 o func (db *UserDB) Authenticate(name string, pw Password) error {
139 7583dd64 2022-04-13 o 	u, err := db.Lookup(name)
140 7583dd64 2022-04-13 o 	if err != nil {
141 7583dd64 2022-04-13 o 		return fmt.Errorf("authenticate %s: %w", name, err)
142 7583dd64 2022-04-13 o 	}
143 7583dd64 2022-04-13 o 	if err := bcrypt.CompareHashAndPassword(u.password, pw); err != nil {
144 7583dd64 2022-04-13 o 		return fmt.Errorf("authenticate %s: %w", name, err)
145 7583dd64 2022-04-13 o 	}
146 7583dd64 2022-04-13 o 	return nil
147 7583dd64 2022-04-13 o }
148 7583dd64 2022-04-13 o 
149 8d82f4f7 2022-04-12 o // TODO tickets aren't implemented yet
150 8d82f4f7 2022-04-12 o func createTicket(dir, username string, pw Password) error {
151 8d82f4f7 2022-04-12 o 	f, err := os.Create(path.Join(dir, username))
152 8d82f4f7 2022-04-12 o 	if err != nil {
153 8d82f4f7 2022-04-12 o 		return err
154 8d82f4f7 2022-04-12 o 	}
155 8d82f4f7 2022-04-12 o 	defer f.Close()
156 8d82f4f7 2022-04-12 o 
157 8d82f4f7 2022-04-12 o 	// TODO hash username, password, random bytes
158 8d82f4f7 2022-04-12 o 	// _, err := f.Write(b)
159 8d82f4f7 2022-04-12 o 	if _, err := f.Write(testTicket); err != nil {
160 8d82f4f7 2022-04-12 o 		return err
161 8d82f4f7 2022-04-12 o 	}
162 8d82f4f7 2022-04-12 o 	return nil
163 8d82f4f7 2022-04-12 o }