Merge r1878890 from trunk:

mod_ldap: Use the LDAP API directly to implement the rebind callback
for modern versions of OpenLDAP, avoiding the overhead of the apr-util
implementation.

* modules/ldap/util_ldap.c:
  Define USE_APR_LDAP_REBIND if a modern version of OpenLDAP is used.
  (uldap_rebind_proc): New function.
  (uldap_rebind_init, uldap_rebind_add): Define, using either the
  callback or the (bad) APR-util versions.
  (uldap_connection_unbind): Clear the rebind pool to remove rebind
  references prior to destroying the LDAP *.
  Omit for !USE_APR_LDAP_REBIND.
  (uldap_connection_init): Use new wrappers, only create the rebind
  pool if USE_APR_LDAP_REBIND.

* include/util_ldap.h: Don't include apr_ldap_rebind.h here.

PR: 64414
Github: closes #124
Reviewed by: jorton, covener, ylavic (by inspection)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1910853 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/changes-entries/ldap-rebind.txt b/changes-entries/ldap-rebind.txt
new file mode 100644 (file)
index 0000000..77cdd61
--- /dev/null
+++ b/changes-entries/ldap-rebind.txt
@@ -0,0 +1,2 @@
+  *) mod_ldap: Avoid performance overhead of APR-util rebind cache for
+     OpenLDAP 2.2+.  PR 64414.  [Joe Orton]

diff --git a/include/util_ldap.h b/include/util_ldap.h
index 28e076096f1851498c967f5d66743612d917250e..edb8a8124239c315ff77a4a435981cb04f71e95a 100644 (file)
--- a/include/util_ldap.h
+++ b/include/util_ldap.h
@@ -32,7 +32,6 @@
 #if APR_MAJOR_VERSION < 2
 /* The LDAP API is currently only present in APR 1.x */
 #include "apr_ldap.h"
-#include "apr_ldap_rebind.h"
 #else
 #define APR_HAS_LDAP 0
 #endif

diff --git a/modules/ldap/util_ldap.c b/modules/ldap/util_ldap.c
index 14b774a0d82e6bc7a61eedaa77fbe94a35aa21c5..aa0bad1397c4c00c65dabaffa7ada8ded6c996e0 100644 (file)
--- a/modules/ldap/util_ldap.c
+++ b/modules/ldap/util_ldap.c
@@ -75,6 +75,38 @@ module AP_MODULE_DECLARE_DATA ldap_module;
 static const char *ldap_cache_mutex_type = "ldap-cache";
 static apr_status_t uldap_connection_unbind(void *param);
 
+/* For OpenLDAP with the 3-arg version of ldap_set_rebind_proc(), use
+ * a simpler rebind callback than the implementation in APR-util.
+ * Testing for API version >= 3001 appears safe although OpenLDAP
+ * 2.1.x (API version = 2004) also has the 3-arg API. */
+#if APR_HAS_OPENLDAP_LDAPSDK && defined(LDAP_API_VERSION) && LDAP_API_VERSION >= 3001
+
+#define uldap_rebind_init(p) APR_SUCCESS /* noop */
+
+static int uldap_rebind_proc(LDAP *ld, const char *url, ber_tag_t request,
+                             ber_int_t msgid, void *params)
+{
+    util_ldap_connection_t *ldc = params;
+
+    return ldap_bind_s(ld, ldc->binddn, ldc->bindpw, LDAP_AUTH_SIMPLE);
+}
+
+static apr_status_t uldap_rebind_add(util_ldap_connection_t *ldc)
+{
+    ldap_set_rebind_proc(ldc->ldap, uldap_rebind_proc, ldc);
+    return APR_SUCCESS;
+}
+
+#else /* !APR_HAS_OPENLDAP_LDAPSDK */
+
+#define USE_APR_LDAP_REBIND
+#include <apr_ldap_rebind.h>
+
+#define uldap_rebind_init(p) apr_ldap_rebind_init(p)
+#define uldap_rebind_add(ldc) apr_ldap_rebind_add((ldc)->rebind_pool, \
+                                                  (ldc)->ldap, (ldc)->binddn, \
+                                                  (ldc)->bindpw)
+#endif
 
 static APR_INLINE apr_status_t ldap_cache_lock(util_ldap_state_t *st, request_rec *r) { 
     apr_status_t rv = APR_SUCCESS;
@@ -195,6 +227,13 @@ static apr_status_t uldap_connection_unbind(void *param)
     util_ldap_connection_t *ldc = param;
 
     if (ldc) {
+#ifdef USE_APR_LDAP_REBIND
+        /* forget the rebind info for this conn */
+        if (ldc->ChaseReferrals == AP_LDAP_CHASEREFERRALS_ON) {
+            apr_pool_clear(ldc->rebind_pool);
+        }
+#endif
+
         if (ldc->ldap) {
             if (ldc->r) { 
                 ap_log_rerror(APLOG_MARK, APLOG_TRACE5, 0, ldc->r, "LDC %pp unbind", ldc); 
@@ -203,12 +242,6 @@ static apr_status_t uldap_connection_unbind(void *param)
             ldc->ldap = NULL;
         }
         ldc->bound = 0;
-
-        /* forget the rebind info for this conn */
-        if (ldc->ChaseReferrals == AP_LDAP_CHASEREFERRALS_ON) {
-            apr_ldap_rebind_remove(ldc->ldap);
-            apr_pool_clear(ldc->rebind_pool);
-        }
     }
 
     return APR_SUCCESS;
@@ -344,7 +377,7 @@ static int uldap_connection_init(request_rec *r,
 
     if (ldc->ChaseReferrals == AP_LDAP_CHASEREFERRALS_ON) {
         /* Now that we have an ldap struct, add it to the referral list for rebinds. */
-        rc = apr_ldap_rebind_add(ldc->rebind_pool, ldc->ldap, ldc->binddn, ldc->bindpw);
+        rc = uldap_rebind_add(ldc);
         if (rc != APR_SUCCESS) {
             ap_log_error(APLOG_MARK, APLOG_ERR, rc, r->server, APLOGNO(01277)
                     "LDAP: Unable to add rebind cross reference entry. Out of memory?");
@@ -870,6 +903,7 @@ static util_ldap_connection_t *
         /* whether or not to keep this connection in the pool when it's returned */
         l->keep = (st->connection_pool_ttl == 0) ? 0 : 1;
 
+#ifdef USE_APR_LDAP_REBIND
         if (l->ChaseReferrals == AP_LDAP_CHASEREFERRALS_ON) {
             if (apr_pool_create(&(l->rebind_pool), l->pool) != APR_SUCCESS) {
                 ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, APLOGNO(01286)
@@ -881,6 +915,7 @@ static util_ldap_connection_t *
             }
             apr_pool_tag(l->rebind_pool, "util_ldap_rebind");
         }
+#endif
 
         if (p) {
             p->next = l;
@@ -3070,7 +3105,7 @@ static int util_ldap_post_config(apr_pool_t *p, apr_pool_t *plog,
     }
 
     /* Initialize the rebind callback's cross reference list. */
-    apr_ldap_rebind_init (p);
+    (void) uldap_rebind_init(p);
 
 #ifdef AP_LDAP_OPT_DEBUG
     if (st->debug_level > 0) {