Merge r1885939, r1885940, r1885941, r1885945 from trunk:

Do not allow to set empty bind passwords to be set via AuthLDAPBindPassword

Binds with empty passwords always succeed, but in case the password of the
user was not empty subsequent LDAP operations fail.

Before doing any bind check that the provided username is not NULL and that the
password is neither NULL nor empty.

Binds with empty passwords always succeed, but in case the password of the
user was not empty subsequent LDAP operations fail.
This causes authentications that use user supplied credentials
(AuthLDAPInitialBindAsUser set to on) to fail with status code 500 instead of
401 if the user supplied an empty password.

* Document r1885939 and r1885940

* Add lognumber

Reviewed by: rpluem, ylavic, covener

Github: closes #168

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1887080 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 5af3c081b938bda2c889fde7a75d4550139f8790..47ac08b2b5dbfea559f4d5cf7be0244de9553b39 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.4.47
 
+  *) mod_authnz_ldap: Prevent authentications with empty passwords for the
+     initial bind to fail with status 500. [Ruediger Pluem]
+
   *) mod_auth_digest: Fast validation of the nonce's base64 to fail early if
      the format can't match anyway.  [Yann Ylavic]
 

diff --git a/modules/aaa/mod_authnz_ldap.c b/modules/aaa/mod_authnz_ldap.c
index 4634fe96857146da1923d4bfdd4bccb1de9b5306..a7b4939752e7306bf4b023138b7feaa21abd7a70 100644 (file)
--- a/modules/aaa/mod_authnz_ldap.c
+++ b/modules/aaa/mod_authnz_ldap.c
@@ -500,6 +500,32 @@ static authn_status authn_ldap_check_password(request_rec *r, const char *user,
         return AUTH_GENERAL_ERROR;
     }
 
+    /* Get the password that the client sent */
+    if (password == NULL) {
+        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01692)
+                      "auth_ldap authenticate: no password specified");
+        return AUTH_GENERAL_ERROR;
+    }
+
+    if (user == NULL) {
+        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01693)
+                      "auth_ldap authenticate: no user specified");
+        return AUTH_GENERAL_ERROR;
+    }
+
+    /*
+     * A bind to the server with an empty password always succeeds, so
+     * we check to ensure that the password is not empty. This implies
+     * that users who actually do have empty passwords will never be
+     * able to authenticate with this module. I don't see this as a big
+     * problem.
+     */
+    if (!(*password)) {
+        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(10263)
+                      "auth_ldap authenticate: empty password specified");
+        return AUTH_DENIED;
+    }
+
     /* There is a good AuthLDAPURL, right? */
     if (sec->host) {
         const char *binddn = sec->binddn;
@@ -522,21 +548,6 @@ static authn_status authn_ldap_check_password(request_rec *r, const char *user,
     ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01691)
                   "auth_ldap authenticate: using URL %s", sec->url);
 
-    /* Get the password that the client sent */
-    if (password == NULL) {
-        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01692)
-                      "auth_ldap authenticate: no password specified");
-        util_ldap_connection_close(ldc);
-        return AUTH_GENERAL_ERROR;
-    }
-
-    if (user == NULL) {
-        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01693)
-                      "auth_ldap authenticate: no user specified");
-        util_ldap_connection_close(ldc);
-        return AUTH_GENERAL_ERROR;
-    }
-
     /* build the username filter */
     authn_ldap_build_filter(filtbuf, r, user, NULL, sec);
 
@@ -1673,6 +1684,10 @@ static const char *set_bind_password(cmd_parms *cmd, void *_cfg, const char *arg
         sec->bindpw = (char *)arg;
     }
 
+    if (!(*sec->bindpw)) {
+        return "Empty passwords are invalid for AuthLDAPBindPassword";
+    }
+
     return NULL;
 }