Merge pull request iovisor#4544 from michalgr/fix_short_zip_parsing

bcc_zip_archive_open should not loop indefinitely for bad archives

src/cc/bcc_zip.c

@@ -202,9 +202,9 @@ static int find_central_directory(struct bcc_zip_archive* archive) {
  // Because the end of central directory ends with a variable length array of
  // up to 0xFFFF bytes we can't know exactly where it starts and need to
  // search for it at the end of the file, scanning the (limit, offset] range.
- uint32_t offset =
- archive->size - sizeof(struct end_of_central_directory_record);
- int64_t limit = (int64_t)offset - (1 << 16);
+ int64_t offset =
+ (int64_t)archive->size - sizeof(struct end_of_central_directory_record);
+ int64_t limit = offset - (1 << 16);
  for (; offset >= 0 && offset > limit && rc == -1; offset--) {
  rc = try_parse_end_of_central_directory(archive, offset);
  }

tests/cc/test_zip.cc

@@ -21,6 +21,7 @@
 
 #define LIB_ENTRY_NAME "libdebuginfo_test_lib.so"
 #define ENTRY_IN_SUBDIR_NAME "zip_subdir/file.txt"
+#define NOT_AN_ARCHIVE_PATH CMAKE_CURRENT_BINARY_DIR "/dummy_proc_map.txt"
 #define TEST_ARCHIVE_PATH CMAKE_CURRENT_BINARY_DIR "/archive.zip"
 
 namespace {
@@ -47,6 +48,11 @@ const void* get_uncompressed_data(const bcc_zip_entry& entry) {
 
 } // namespace
 
+TEST_CASE("returns error for non-zip files", "[zip]") {
+ bcc_zip_archive* archive = bcc_zip_archive_open(NOT_AN_ARCHIVE_PATH);
+ REQUIRE(archive == nullptr);
+}
+
 TEST_CASE("finds entries in a zip archive by name", "[zip]") {
  bcc_zip_archive* archive = bcc_zip_archive_open(TEST_ARCHIVE_PATH);
  REQUIRE(archive != nullptr);