autofs-5.0.6 - fix segfault in get_query_dn()

From: Leonardo Chiquitto <leonardo.lists@gmail.com>

Automount will segfault when two threads run get_query_dn()
simultaneously and $SEARCH_BASE is defined in sysconfig.
This happens because a thread tries to dereference ctxt->sdns
while another thread running the same function frees the
memory.

I believe we don't need to reread $SEARCH_BASE every time
get_query_dn() is called.

edit: Ian Kent <raven@themaw.net>
move the read of configured search dns to lookup_init().
edit end
---

 modules/lookup_ldap.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)


--- autofs-5.0.6.orig/modules/lookup_ldap.c
+++ autofs-5.0.6/modules/lookup_ldap.c
@@ -281,7 +281,6 @@ static int get_query_dn(unsigned logopt,
 	char buf[MAX_ERR_BUF];
 	char *query, *dn, *qdn;
 	LDAPMessage *result, *e;
-	struct ldap_searchdn *sdns = NULL;
 	char *attrs[2];
 	struct berval **value;
 	int scope;
@@ -330,15 +329,6 @@ static int get_query_dn(unsigned logopt,
 		scope = LDAP_SCOPE_SUBTREE;
 	}
 
-	if (!ctxt->base) {
-		sdns = defaults_get_searchdns();
-		if (sdns) {
-			if (ctxt->sdns)
-				defaults_free_searchdns(ctxt->sdns);
-			ctxt->sdns = sdns;
-		}
-	}
-
 	dn = NULL;
 	if (!ctxt->sdns) {
 		rv = ldap_search_s(ldap, ctxt->base,
@@ -1467,6 +1457,9 @@ int lookup_init(const char *mapfmt, int
 		return 1;
 	}
 
+	if (!ctxt->base)
+		ctxt->sdns = defaults_get_searchdns();
+
 	ctxt->timeout = defaults_get_ldap_timeout();
 	ctxt->network_timeout = defaults_get_ldap_network_timeout();