135 lines
3.1 KiB
Go
135 lines
3.1 KiB
Go
package main
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import (
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"errors"
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"fmt"
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"net/http"
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"github.com/go-ldap/ldap/v3"
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)
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/* Check credentials against LDAP */
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type LdapPreAuth struct {
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WithConfig *Config
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OnWrongPassword ErrorHandler
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OnFailure ErrorHandler
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OnCreds CredsHandler
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}
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func (l LdapPreAuth) WithCreds(username, password string) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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var e *LdapWrongPasswordError
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access_key, secret_key, err := LdapGetS3(l.WithConfig, username, password)
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if err == nil {
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l.OnCreds.WithCreds(access_key, secret_key).ServeHTTP(w, r)
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} else if errors.As(err, &e) {
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l.OnWrongPassword.WithError(err).ServeHTTP(w, r)
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} else {
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l.OnFailure.WithError(e).ServeHTTP(w, r)
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}
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})
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}
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/**
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* Private logic
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*/
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type ldapConnector struct {
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conn *ldap.Conn
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config *Config
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userDn string
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}
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type LdapError struct {
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Username string
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Err error
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}
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func (e *LdapError) Error() string { return "ldap error for "+e.Username+": "+e.Err.Error() }
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type LdapWrongPasswordError struct { LdapError }
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func LdapGetS3(c *Config, username, password string) (access_key, secret_key string, werr error) {
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// 1. Connect to the server
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conn, err := ldapConnect(c)
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if err != nil {
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werr = &LdapError { username, err }
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return
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}
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defer conn.Close()
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// 2. Authenticate with provided credentials
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// @FIXME we should better check the error, it could also be due to an LDAP error
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err = conn.auth(username, password)
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if err != nil {
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werr = &LdapWrongPasswordError { LdapError { username, err } }
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return
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}
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// 3. Fetch user's profile
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profile, err := conn.profile()
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if err != nil {
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werr = &LdapError { username, err }
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return
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}
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// 4. Basic checks upon users' attributes
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access_key = profile.GetAttributeValue("garage_s3_access_key")
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secret_key = profile.GetAttributeValue("garage_s3_secret_key")
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if access_key == "" || secret_key == "" {
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err = errors.New(fmt.Sprintf("Either access key or secret key is missing in LDAP for %s", conn.userDn))
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werr = &LdapError { username, err }
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return
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}
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// 5. Send fetched credentials to the next middleware
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return
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}
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func ldapConnect(c *Config) (ldapConnector, error) {
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ldapSock, err := ldap.Dial("tcp", c.LdapServer)
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if err != nil {
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return ldapConnector{}, err
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}
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return ldapConnector{
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conn: ldapSock,
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config: c,
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}, nil
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}
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func (l *ldapConnector) auth(username, password string) error {
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l.userDn = fmt.Sprintf("%s=%s,%s", l.config.UserNameAttr, username, l.config.UserBaseDN)
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return l.conn.Bind(l.userDn, password)
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}
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func (l *ldapConnector) profile() (*ldap.Entry, error) {
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searchRequest := ldap.NewSearchRequest(
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l.userDn,
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ldap.ScopeBaseObject,
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ldap.NeverDerefAliases,
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0,
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0,
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false,
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"(objectClass=*)",
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[]string{"garage_s3_access_key", "garage_s3_secret_key"},
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nil)
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sr, err := l.conn.Search(searchRequest)
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if err != nil {
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return nil, err
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}
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if len(sr.Entries) != 1 {
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return nil, errors.New(fmt.Sprintf("Wrong number of LDAP entries, expected 1, got %d", len(sr.Entries)))
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}
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return sr.Entries[0], nil
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}
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func (l *ldapConnector) Close() {
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if l.conn != nil {
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l.conn.Close()
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l.conn = nil
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}
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}
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