Prevent winbindd from segfaulting due to corrupted cache tdb.

If we try to flush the caches and due to a corrupted tdb we and have no tdb
context close the tdb and validate it. Initialize the cache afterwards again.
(This used to be commit d0c0f91fb9f3438a18c6f47ed894f525beb75cbf)

2 files changed, 36 insertions, 4 deletions

diff --git a/source3/winbindd/winbindd.c b/source3/winbindd/winbindd.c
index 07cf22618e..dfad50bf96 100644
--- a/source3/winbindd/winbindd.c
+++ b/source3/winbindd/winbindd.c
@@ -121,7 +121,23 @@ static void flush_caches(void)
            otherwise cached access denied errors due to restrict anonymous
            hang around until the sequence number changes. */
 
-	wcache_invalidate_cache();
+	if (wcache_invalidate_cache() < 0) {
+		DEBUG(0, ("invalidating the cache failed; revalidate the cache\n"));
+		/* Close the cache to be able to valdite the cache */
+		close_winbindd_cache();
+		/*
+		 * Ensure all cache and idmap caches are consistent
+		 * before we initialize the cache again.
+		 */
+		if (winbindd_validate_cache() < 0) {
+			DEBUG(0, ("corrupted tdb found, trying to restore backup\n"));
+		}
+
+		/* Initialize cache again. */
+		if (!initialize_winbindd_cache()) {
+			exit(1);
+		}
+	}
 }
 
 /* Handle the signal by unlinking socket and exiting */
diff --git a/source3/winbindd/winbindd_cache.c b/source3/winbindd/winbindd_cache.c
index f63c7a5b2f..62a68aa8aa 100644
--- a/source3/winbindd/winbindd_cache.c
+++ b/source3/winbindd/winbindd_cache.c
@@ -2261,7 +2261,7 @@ void wcache_invalidate_samlogon(struct winbindd_domain *domain,
 	netsamlogon_clear_cached_user(cache->tdb, info3);
 }
 
-void wcache_invalidate_cache(void)
+int wcache_invalidate_cache(void)
 {
 	struct winbindd_domain *domain;
 
@@ -2270,9 +2270,15 @@ void wcache_invalidate_cache(void)
 
 		DEBUG(10, ("wcache_invalidate_cache: invalidating cache "
 			   "entries for %s\n", domain->name));
-		if (cache)
-			tdb_traverse(cache->tdb, traverse_fn, NULL);
+		if (cache) {
+			if (cache->tdb) {
+				tdb_traverse(cache->tdb, traverse_fn, NULL);
+			} else {
+				return -1;
+			}
+		}
 	}
+	return 0;
 }
 
 bool init_wcache(void)
@@ -2354,6 +2360,16 @@ bool initialize_winbindd_cache(void)
 	return True;
 }
 
+void close_winbindd_cache()
+{
+	if (!wcache)
+		return;
+	if (wcache->tdb) {
+		tdb_close(wcache->tdb);
+		wcache->tdb = NULL;
+	}
+}
+
 void cache_store_response(pid_t pid, struct winbindd_response *response)
 {
 	fstring key_str;