s4-ldb: cope better with corruption of tdb records

When doing an indexed search if we hit a corrupt record we abandoned
the indexed search and did a full search. The problem was that we
might have sent some records to the caller already, which means the
caller ended up with duplicate records. Fix this by returning a search
error if indexing returns an error and we have given any records to
the caller.

4 files changed, 30 insertions, 5 deletions

diff --git a/source4/lib/ldb/ldb_tdb/ldb_index.c b/source4/lib/ldb/ldb_tdb/ldb_index.c
index 85fbfa0458..b959471d16 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_index.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_index.c
@@ -1037,7 +1037,8 @@ static int ltdb_index_dn(struct ldb_module *module,
   extracting just the given attributes
 */
 static int ltdb_index_filter(const struct dn_list *dn_list,
-			     struct ltdb_context *ac)
+			     struct ltdb_context *ac, 
+			     uint32_t *match_count)
 {
 	struct ldb_context *ldb;
 	struct ldb_message *msg;
@@ -1093,6 +1094,8 @@ static int ltdb_index_filter(const struct dn_list *dn_list,
 			ac->request_terminated = true;
 			return ret;
 		}
+
+		(*match_count)++;
 	}
 
 	return LDB_SUCCESS;
@@ -1103,7 +1106,7 @@ static int ltdb_index_filter(const struct dn_list *dn_list,
   returns -1 if an indexed search is not possible, in which
   case the caller should call ltdb_search_full()
 */
-int ltdb_search_indexed(struct ltdb_context *ac)
+int ltdb_search_indexed(struct ltdb_context *ac, uint32_t *match_count)
 {
 	struct ldb_context *ldb;
 	void *data = ldb_module_get_private(ac->module);
@@ -1166,7 +1169,7 @@ int ltdb_search_indexed(struct ltdb_context *ac)
 	if (ret == LDB_SUCCESS) {
 		/* we've got a candidate list - now filter by the full tree
 		   and extract the needed attributes */
-		ret = ltdb_index_filter(dn_list, ac);
+		ret = ltdb_index_filter(dn_list, ac, match_count);
 	}
 
 	talloc_free(dn_list);
@@ -1578,6 +1581,8 @@ static int re_index(struct tdb_context *tdb, TDB_DATA key, TDB_DATA data, void *
 
 	ret = ltdb_unpack_data(module, &data, msg);
 	if (ret != 0) {
+		ldb_debug(ldb, LDB_DEBUG_ERROR, "Invalid data for index %s\n",
+			  ldb_dn_get_linearized(msg->dn));
 		talloc_free(msg);
 		return -1;
 	}
diff --git a/source4/lib/ldb/ldb_tdb/ldb_pack.c b/source4/lib/ldb/ldb_tdb/ldb_pack.c
index 5640e7053c..e7aeb47e72 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_pack.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_pack.c
@@ -236,6 +236,10 @@ int ltdb_unpack_data(struct ldb_module *module,
 			errno = EIO;
 			goto failed;
 		}
+		if (len == 0) {
+			errno = EIO;
+			goto failed;
+		}
 		message->elements[i].flags = 0;
 		message->elements[i].name = talloc_strndup(message->elements, (char *)p, len);
 		if (message->elements[i].name == NULL) {
diff --git a/source4/lib/ldb/ldb_tdb/ldb_search.c b/source4/lib/ldb/ldb_tdb/ldb_search.c
index b307c5fb2f..a6647ccd50 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_search.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_search.c
@@ -265,6 +265,9 @@ int ltdb_search_dn1(struct ldb_module *module, struct ldb_dn *dn, struct ldb_mes
 	ret = ltdb_unpack_data(module, &tdb_data, msg);
 	free(tdb_data.dptr);
 	if (ret == -1) {
+		struct ldb_context *ldb = ldb_module_get_ctx(module);
+		ldb_debug(ldb, LDB_DEBUG_ERROR, "Invalid data for index %s\n",
+			  ldb_dn_get_linearized(msg->dn));
 		return LDB_ERR_OPERATIONS_ERROR;		
 	}
 
@@ -535,7 +538,9 @@ int ltdb_search(struct ltdb_context *ctx)
 	ctx->attrs = req->op.search.attrs;
 
 	if (ret == LDB_SUCCESS) {
-		ret = ltdb_search_indexed(ctx);
+		uint32_t match_count = 0;
+
+		ret = ltdb_search_indexed(ctx, &match_count);
 		if (ret == LDB_ERR_NO_SUCH_OBJECT) {
 			/* Not in the index, therefore OK! */
 			ret = LDB_SUCCESS;
@@ -553,6 +558,17 @@ int ltdb_search(struct ltdb_context *ctx)
 			printf("FULL SEARCH: %s\n", expression);
 			talloc_free(expression);
 #endif
+			if (match_count != 0) {
+				/* the indexing code gave an error
+				 * after having returned at least one
+				 * entry. This means the indexes are
+				 * corrupt or a database record is
+				 * corrupt. We cannot continue with a
+				 * full search or we may return
+				 * duplicate entries
+				 */
+				return LDB_ERR_OPERATIONS_ERROR;
+			}
 			ret = ltdb_search_full(ctx);
 			if (ret != LDB_SUCCESS) {
 				ldb_set_errstring(ldb, "Indexed and full searches both failed!\n");
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.h b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
index 75034dcf4b..c8c1dad5de 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.h
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
@@ -82,7 +82,7 @@ int ltdb_check_at_attributes_values(const struct ldb_val *value);
 
 struct ldb_parse_tree;
 
-int ltdb_search_indexed(struct ltdb_context *ctx);
+int ltdb_search_indexed(struct ltdb_context *ctx, uint32_t *);
 int ltdb_index_add(struct ldb_module *module, const struct ldb_message *msg);
 int ltdb_index_del(struct ldb_module *module, const struct ldb_message *msg);
 int ltdb_index_one(struct ldb_module *module, const struct ldb_message *msg, int add);