postgres.go

package backends

import (
	"database/sql"
	"fmt"
	"strconv"
	"strings"

	"github.com/iegomez/mosquitto-go-auth/backends/topics"
	"github.com/iegomez/mosquitto-go-auth/hashing"
	"github.com/jmoiron/sqlx"
	_ "github.com/lib/pq"
	"github.com/pkg/errors"
	log "github.com/sirupsen/logrus"
)

//Postgres holds all fields of the postgres db connection.
type Postgres struct {
	DB             *sqlx.DB
	Host           string
	Port           string
	DBName         string
	User           string
	Password       string
	UserQuery      string
	SuperuserQuery string
	AclQuery       string
	SSLMode        string
	SSLCert        string
	SSLKey         string
	SSLRootCert    string
	hasher         hashing.HashComparer
	maxLifeTime    int64

	connectTries int
}

func NewPostgres(authOpts map[string]string, logLevel log.Level, hasher hashing.HashComparer) (Postgres, error) {

	log.SetLevel(logLevel)

	//Set defaults for postgres

	pgOk := true
	missingOptions := ""

	var postgres = Postgres{
		Host:           "localhost",
		Port:           "5432",
		SSLMode:        "verify-full",
		SuperuserQuery: "",
		AclQuery:       "",
		hasher:         hasher,
	}

	if host, ok := authOpts["pg_host"]; ok {
		postgres.Host = host
	}

	if port, ok := authOpts["pg_port"]; ok {
		postgres.Port = port
	}

	if dbName, ok := authOpts["pg_dbname"]; ok {
		postgres.DBName = dbName
	} else {
		pgOk = false
		missingOptions += " pg_dbname"
	}

	if user, ok := authOpts["pg_user"]; ok {
		postgres.User = user
	} else {
		pgOk = false
		missingOptions += " pg_user"
	}

	if password, ok := authOpts["pg_password"]; ok {
		postgres.Password = password
	} else {
		pgOk = false
		missingOptions += " pg_password"
	}

	if userQuery, ok := authOpts["pg_userquery"]; ok {
		postgres.UserQuery = userQuery
	} else {
		pgOk = false
		missingOptions += " pg_userquery"
	}

	if superuserQuery, ok := authOpts["pg_superquery"]; ok {
		postgres.SuperuserQuery = superuserQuery
	}

	if aclQuery, ok := authOpts["pg_aclquery"]; ok {
		postgres.AclQuery = aclQuery
	}

	if sslmode, ok := authOpts["pg_sslmode"]; ok {
		switch sslmode {
		case "verify-full", "verify-ca", "require", "disable":
		default:
			log.Warnf("PG backend warning: using unknown pg_sslmode: '%s'", sslmode)
		}
		postgres.SSLMode = sslmode
	} else {
		postgres.SSLMode = "verify-full"
	}

	if sslCert, ok := authOpts["pg_sslcert"]; ok {
		postgres.SSLCert = sslCert
	}

	if sslKey, ok := authOpts["pg_sslkey"]; ok {
		postgres.SSLKey = sslKey
	}

	if sslRootCert, ok := authOpts["pg_sslrootcert"]; ok {
		postgres.SSLRootCert = sslRootCert
	}

	//Exit if any mandatory option is missing.
	if !pgOk {
		return postgres, errors.Errorf("PG backend error: missing options: %s", missingOptions)
	}

	//Build the dsn string and try to connect to the db.
	connStr := fmt.Sprintf("user=%s password=%s dbname=%s host=%s port=%s", postgres.User, postgres.Password, postgres.DBName, postgres.Host, postgres.Port)

	switch postgres.SSLMode {
	case "disable":
		connStr = fmt.Sprintf("%s sslmode=disable", connStr)
	case "require":
		connStr = fmt.Sprintf("%s sslmode=require", connStr)
	case "verify-ca":
		connStr = fmt.Sprintf("%s sslmode=verify-ca", connStr)
	case "verify-full":
		fallthrough
	default:
		connStr = fmt.Sprintf("%s sslmode=verify-full", connStr)
	}

	if postgres.SSLRootCert != "" {
		connStr = fmt.Sprintf("%s sslrootcert=%s", connStr, postgres.SSLRootCert)
	}

	if postgres.SSLKey != "" {
		connStr = fmt.Sprintf("%s sslkey=%s", connStr, postgres.SSLKey)
	}

	if postgres.SSLCert != "" {
		connStr = fmt.Sprintf("%s sslcert=%s", connStr, postgres.SSLCert)
	}

	if tries, ok := authOpts["pg_connect_tries"]; ok {
		connectTries, err := strconv.Atoi(tries)

		if err != nil {
			log.Warnf("invalid postgres connect tries options: %s", err)
		} else {
			postgres.connectTries = connectTries
		}
	}

	if maxLifeTime, ok := authOpts["pg_max_life_time"]; ok {
		lifeTime, err := strconv.ParseInt(maxLifeTime, 10, 64)

		if err == nil {
			postgres.maxLifeTime = lifeTime
		}
	}

	var err error
	postgres.DB, err = OpenDatabase(connStr, "postgres", postgres.connectTries, postgres.maxLifeTime)

	if err != nil {
		return postgres, errors.Errorf("PG backend error: couldn't open db: %s", err)
	}

	return postgres, nil

}

//GetUser checks that the username exists and the given password hashes to the same password.
func (o Postgres) GetUser(username, password, clientid string) (bool, error) {

	var pwHash sql.NullString
	err := o.DB.Get(&pwHash, o.UserQuery, username)

	if err != nil {
		if err == sql.ErrNoRows {
			// avoid leaking the fact that user exists or not though error.
			return false, nil
		}

		log.Debugf("PG get user error: %s", err)
		return false, err
	}

	if !pwHash.Valid {
		log.Debugf("PG get user error: user %s not found", username)
		return false, err
	}

	if o.hasher.Compare(password, pwHash.String) {
		return true, nil
	}

	return false, nil

}

//GetSuperuser checks that the username meets the superuser query.
func (o Postgres) GetSuperuser(username string) (bool, error) {

	//If there's no superuser query, return false.
	if o.SuperuserQuery == "" {
		return false, nil
	}

	var count sql.NullInt64
	err := o.DB.Get(&count, o.SuperuserQuery, username)

	if err != nil {
		if err == sql.ErrNoRows {
			// avoid leaking the fact that user exists or not though error.
			return false, nil
		}

		log.Debugf("PG get superuser error: %s", err)
		return false, err
	}

	if !count.Valid {
		log.Debugf("PG get superuser error: user %s not found", username)
		return false, nil
	}

	if count.Int64 > 0 {
		return true, nil
	}

	return false, nil

}

//CheckAcl gets all acls for the username and tries to match against topic, acc, and username/clientid if needed.
func (o Postgres) CheckAcl(username, topic, clientid string, acc int32) (bool, error) {

	//If there's no acl query, assume all privileges for all users.
	if o.AclQuery == "" {
		return true, nil
	}

	var acls []string

	err := o.DB.Select(&acls, o.AclQuery, username, acc)

	if err != nil {
		log.Debugf("PG check acl error: %s", err)
		return false, err
	}

	for _, acl := range acls {
		aclTopic := strings.Replace(acl, "%c", clientid, -1)
		aclTopic = strings.Replace(aclTopic, "%u", username, -1)
		if topics.Match(aclTopic, topic) {
			return true, nil
		}
	}

	return false, nil

}

//GetName returns the backend's name
func (o Postgres) GetName() string {
	return "Postgres"
}

//Halt closes the mysql connection.
func (o Postgres) Halt() {
	if o.DB != nil {
		err := o.DB.Close()
		if err != nil {
			log.Errorf("Postgres cleanup error: %s", err)
		}
	}
}