directory_iterator: consistency check on open

lib/directory/directory_iterator.c

@@ -76,7 +76,7 @@ load_metablock(
 }
 
 static int
-check_consistency(struct SqshDirectoryIterator *iterator) {
+check_consistency(const struct SqshDirectoryIterator *iterator) {
 	const char *name = sqsh_directory_iterator_name(iterator);
 	const size_t name_len = sqsh_directory_iterator_name_size(iterator);
 
@@ -269,13 +269,48 @@ sqsh_directory_iterator_file_type(
 	return SQSH_FILE_TYPE_UNKNOWN;
 }
 
+static int
+check_file_consistency(
+		const struct SqshDirectoryIterator *iterator,
+		const struct SqshFile *file) {
+	const uint64_t file_inode = sqsh_file_inode(file);
+	const uint64_t iter_inode = sqsh_directory_iterator_inode_number(iterator);
+	if (iter_inode != file_inode) {
+		return -SQSH_ERROR_CORRUPTED_DIRECTORY_ENTRY;
+	}
+
+	enum SqshFileType file_type = sqsh_file_type(file);
+	enum SqshFileType iter_type = sqsh_directory_iterator_file_type(iterator);
+	if (iter_type != file_type) {
+		return -SQSH_ERROR_CORRUPTED_DIRECTORY_ENTRY;
+	}
+	return 0;
+}
+
 struct SqshFile *
 sqsh_directory_iterator_open_file(
 		const struct SqshDirectoryIterator *iterator, int *err) {
+	int rv = 0;
+	struct SqshFile *file = NULL;
 	const uint64_t inode_ref = sqsh_directory_iterator_inode_ref(iterator);
 	struct SqshArchive *archive = iterator->file->archive;
 
-	return sqsh_open_by_ref(archive, inode_ref, err);
+	file = sqsh_open_by_ref(archive, inode_ref, &rv);
+	if (file == NULL) {
+		goto out;
+	}
+
+	rv = check_file_consistency(iterator, file);
+
+out:
+	if (rv < 0) {
+		sqsh_close(file);
+		file = NULL;
+	}
+	if (err != NULL) {
+		*err = rv;
+	}
+	return file;
 }
 
 static int

test/directory/directory_iterator.c

@@ -207,9 +207,55 @@ iter_invalid_file_type(void) {
 	sqsh__archive_cleanup(&archive);
 }
 
+static void
+iter_inconsistent_file_type(void) {
+	int rv;
+	struct SqshArchive archive = {0};
+	uint8_t payload[] = {
+			/* clang-format off */
+			SQSH_HEADER,
+			/* inode */
+			[INODE_TABLE_OFFSET] = METABLOCK_HEADER(0, 1024),
+			INODE_HEADER(1, 0, 0, 0, 0, 1),
+			INODE_BASIC_DIR(0, 1024, 0, 0),
+			[INODE_TABLE_OFFSET+2+128] =
+			INODE_HEADER(3, 0, 0, 0, 0, 2),
+			INODE_BASIC_SYMLINK(3),
+			't', 'g', 't',
+			[DIRECTORY_TABLE_OFFSET] = METABLOCK_HEADER(0, 128),
+			DIRECTORY_HEADER(2, 0, 0),
+			DIRECTORY_ENTRY(128, 2, 1, 1),
+			'1',
+			[FRAGMENT_TABLE_OFFSET] = 0,
+			/* clang-format on */
+	};
+	mk_stub(&archive, payload, sizeof(payload));
+
+	struct SqshFile file = {0};
+	rv = sqsh__file_init(&file, &archive, 0);
+	assert(rv == 0);
+
+	struct SqshDirectoryIterator *iter =
+			sqsh_directory_iterator_new(&file, &rv);
+	assert(rv == 0);
+
+	bool has_next = sqsh_directory_iterator_next(iter, &rv);
+	assert(rv == 0);
+	assert(has_next == true);
+
+	struct SqshFile *entry_file = sqsh_directory_iterator_open_file(iter, &rv);
+	assert(rv == -SQSH_ERROR_CORRUPTED_DIRECTORY_ENTRY);
+	assert(entry_file == NULL);
+
+	sqsh_directory_iterator_free(iter);
+	sqsh__file_cleanup(&file);
+	sqsh__archive_cleanup(&archive);
+}
+
 DECLARE_TESTS
 TEST(iter_two_files)
 TEST(iter_invalid_file_name_with_slash)
 TEST(iter_invalid_file_name_with_0)
 TEST(iter_invalid_file_type)
+TEST(iter_inconsistent_file_type)
 END_TESTS