libziparchive: fix issue with a directory with one file

libziparchive fails to iterate some bootanimation archives
reporting invalid offset error. This is caused by failure
to process a directory with one file
(when name_offset + file_name_length == cd_offset).

Change-Id: I2733e7f782c14a6fadd5491bb94318ac968df206

3 files changed, 17 insertions, 1 deletions

diff --git a/libziparchive/testdata/declaredlength.zip b/libziparchive/testdata/declaredlength.zip
new file mode 100644
index 0000000..773380c
--- /dev/null
+++ b/libziparchive/testdata/declaredlength.zip
diff --git a/libziparchive/zip_archive.cc b/libziparchive/zip_archive.cc
index e820f2a..6475649 100644
--- a/libziparchive/zip_archive.cc
+++ b/libziparchive/zip_archive.cc
@@ -824,7 +824,7 @@ static int32_t FindEntry(const ZipArchive* archive, const int ent,
   // name in the central directory.
   if (lfh->file_name_length == nameLen) {
     const off64_t name_offset = local_header_offset + sizeof(LocalFileHeader);
-    if (name_offset + lfh->file_name_length >= cd_offset) {
+    if (name_offset + lfh->file_name_length > cd_offset) {
       ALOGW("Zip: Invalid declared length");
       return kInvalidOffset;
     }
diff --git a/libziparchive/zip_archive_test.cc b/libziparchive/zip_archive_test.cc
index c8dafa9..64faa6d 100644
--- a/libziparchive/zip_archive_test.cc
+++ b/libziparchive/zip_archive_test.cc
@@ -171,6 +171,22 @@ TEST(ziparchive, FindEntry) {
   CloseArchive(handle);
 }
 
+TEST(ziparchive, TestInvalidDeclaredLength) {
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveWrapper("declaredlength.zip", &handle));
+
+  void* iteration_cookie;
+  ASSERT_EQ(0, StartIteration(handle, &iteration_cookie, NULL));
+
+  ZipEntryName name;
+  ZipEntry data;
+
+  ASSERT_EQ(Next(iteration_cookie, &data, &name), 0);
+  ASSERT_EQ(Next(iteration_cookie, &data, &name), 0);
+
+  CloseArchive(handle);
+}
+
 TEST(ziparchive, ExtractToMemory) {
   ZipArchiveHandle handle;
   ASSERT_EQ(0, OpenArchiveWrapper(kValidZip, &handle));