Merge pull request #376 from jwrdegoede/oss-fuzz-36187-null-ptr-deref…

…-fix Fix null-ptr deref when table->map_sz is 0
mdbtools · Jan 25, 2022 · 2da65ff · 2da65ff
2 parents bcad261 + 4febc7b
commit 2da65ff
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/src/libmdb/table.c b/src/libmdb/table.c
@@ -92,6 +92,12 @@ MdbTableDef *mdb_read_table(MdbCatalogEntry *entry)
 		mdb_free_tabledef(table);
 		return NULL;
 	}
+	/* First byte of usage_map is the map-type and must always be present */
+	if (table->map_sz < 1) {
+		fprintf(stderr, "mdb_read_table: invalid map-size: %zu\n", table->map_sz);
+		mdb_free_tabledef(table);
+		return NULL;
+	}
 	table->usage_map = g_memdup2((char*)buf + row_start, table->map_sz);
 	if (mdb_get_option(MDB_DEBUG_USAGE)) 
 		mdb_buffer_dump(buf, row_start, table->map_sz);