minio/cmd/config/ldap/config.go

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/*
* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package ldap
import (
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"regexp"
"time"
"github.com/minio/minio/pkg/env"
ldap "gopkg.in/ldap.v3"
)
const (
defaultLDAPExpiry = time.Hour * 1
)
// Config contains AD/LDAP server connectivity information.
type Config struct {
IsEnabled bool `json:"enabled"`
// E.g. "ldap.minio.io:636"
ServerAddr string `json:"serverAddr"`
// STS credentials expiry duration
STSExpiryDuration string `json:"stsExpiryDuration"`
stsExpiryDuration time.Duration // contains converted value
RootCAs *x509.CertPool `json:"-"`
// Format string for usernames
UsernameFormat string `json:"usernameFormat"`
GroupSearchBaseDN string `json:"groupSearchBaseDN"`
GroupSearchFilter string `json:"groupSearchFilter"`
GroupNameAttribute string `json:"groupNameAttribute"`
}
// LDAP keys and envs.
const (
ServerAddr = "server_addr"
STSExpiry = "sts_expiry"
UsernameFormat = "username_format"
GroupSearchFilter = "group_search_filter"
GroupNameAttribute = "group_name_attribute"
GroupSearchBaseDN = "group_search_base_dn"
EnvServerAddr = "MINIO_IDENTITY_LDAP_SERVER_ADDR"
EnvSTSExpiry = "MINIO_IDENTITY_LDAP_STS_EXPIRY"
EnvUsernameFormat = "MINIO_IDENTITY_LDAP_USERNAME_FORMAT"
EnvGroupSearchFilter = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER"
EnvGroupNameAttribute = "MINIO_IDENTITY_LDAP_GROUP_NAME_ATTRIBUTE"
EnvGroupSearchBaseDN = "MINIO_IDENTITY_LDAP_GROUP_SEARCH_BASE_DN"
)
// Connect connect to ldap server.
func (l *Config) Connect() (ldapConn *ldap.Conn, err error) {
if l == nil {
// Happens when LDAP is not configured.
return
}
return ldap.DialTLS("tcp", l.ServerAddr, &tls.Config{RootCAs: l.RootCAs})
}
// GetExpiryDuration - return parsed expiry duration.
func (l Config) GetExpiryDuration() time.Duration {
return l.stsExpiryDuration
}
// Lookup - initializes LDAP config, overrides config, if any ENV values are set.
func Lookup(cfg Config, rootCAs *x509.CertPool) (l Config, err error) {
if cfg.ServerAddr == "" && cfg.IsEnabled {
return l, errors.New("ldap server cannot initialize with empty LDAP server")
}
l.RootCAs = rootCAs
ldapServer := env.Get(EnvServerAddr, cfg.ServerAddr)
if ldapServer == "" {
return l, nil
}
l.IsEnabled = true
l.ServerAddr = ldapServer
l.stsExpiryDuration = defaultLDAPExpiry
if v := env.Get(EnvSTSExpiry, cfg.STSExpiryDuration); v != "" {
expDur, err := time.ParseDuration(v)
if err != nil {
return l, errors.New("LDAP expiry time err:" + err.Error())
}
if expDur <= 0 {
return l, errors.New("LDAP expiry time has to be positive")
}
l.STSExpiryDuration = v
l.stsExpiryDuration = expDur
}
if v := env.Get(EnvUsernameFormat, cfg.UsernameFormat); v != "" {
subs, err := NewSubstituter("username", "test")
if err != nil {
return l, err
}
if _, err := subs.Substitute(v); err != nil {
return l, fmt.Errorf("Only username may be substituted in the username format: %s", err)
}
l.UsernameFormat = v
}
grpSearchFilter := env.Get(EnvGroupSearchFilter, cfg.GroupSearchFilter)
grpSearchNameAttr := env.Get(EnvGroupNameAttribute, cfg.GroupNameAttribute)
grpSearchBaseDN := env.Get(EnvGroupSearchBaseDN, cfg.GroupSearchBaseDN)
// Either all group params must be set or none must be set.
allNotSet := grpSearchFilter == "" && grpSearchNameAttr == "" && grpSearchBaseDN == ""
allSet := grpSearchFilter != "" && grpSearchNameAttr != "" && grpSearchBaseDN != ""
if !allNotSet && !allSet {
return l, errors.New("All group related parameters must be set")
}
if allSet {
subs, err := NewSubstituter("username", "test", "usernamedn", "test2")
if err != nil {
return l, err
}
if _, err := subs.Substitute(grpSearchFilter); err != nil {
return l, fmt.Errorf("Only username and usernamedn may be substituted in the group search filter string: %s", err)
}
l.GroupSearchFilter = grpSearchFilter
l.GroupNameAttribute = grpSearchNameAttr
subs, err = NewSubstituter("username", "test", "usernamedn", "test2")
if err != nil {
return l, err
}
if _, err := subs.Substitute(grpSearchBaseDN); err != nil {
return l, fmt.Errorf("Only username and usernamedn may be substituted in the base DN string: %s", err)
}
l.GroupSearchBaseDN = grpSearchBaseDN
}
return
}
// Substituter - This type is to allow restricted runtime
// substitutions of variables in LDAP configuration items during
// runtime.
type Substituter struct {
vals map[string]string
}
// NewSubstituter - sets up the substituter for usage, for e.g.:
//
// subber := NewSubstituter("username", "john")
func NewSubstituter(v ...string) (Substituter, error) {
if len(v)%2 != 0 {
return Substituter{}, errors.New("Need an even number of arguments")
}
vals := make(map[string]string)
for i := 0; i < len(v); i += 2 {
vals[v[i]] = v[i+1]
}
return Substituter{vals: vals}, nil
}
// Substitute - performs substitution on the given string `t`. Returns
// an error if there are any variables in the input that do not have
// values in the substituter. E.g.:
//
// subber.Substitute("uid=${username},cn=users,dc=example,dc=com")
//
// returns "uid=john,cn=users,dc=example,dc=com"
//
// whereas:
//
// subber.Substitute("uid=${usernamedn}")
//
// returns an error.
func (s *Substituter) Substitute(t string) (string, error) {
for k, v := range s.vals {
re := regexp.MustCompile(fmt.Sprintf(`\$\{%s\}`, k))
t = re.ReplaceAllLiteralString(t, v)
}
// Check if all requested substitutions have been made.
re := regexp.MustCompile(`\$\{.*\}`)
if re.MatchString(t) {
return "", errors.New("unsupported substitution requested")
}
return t, nil
}