Fix out of bound read in libziparchive

Change-Id: I29e682f901a7b6529d7b25d98c1cf2387fe0a9b5

diff --git a/libziparchive/zip_archive.cc b/libziparchive/zip_archive.cc
index 986ee72..49097ce 100644 (file)
--- a/libziparchive/zip_archive.cc
+++ b/libziparchive/zip_archive.cc
@@ -386,6 +386,14 @@ static int32_t ParseZipArchive(ZipArchive* archive) {
   const uint8_t* const cd_end = cd_ptr + cd_length;
   const uint8_t* ptr = cd_ptr;
   for (uint16_t i = 0; i < num_entries; i++) {
+    if (ptr > cd_end - sizeof(CentralDirectoryRecord)) {
+      ALOGW("Zip: ran off the end (at %" PRIu16 ")", i);
+#if defined(__ANDROID__)
+      android_errorWriteLog(0x534e4554, "36392138");
+#endif
+      return -1;
+    }
+
     const CentralDirectoryRecord* cdr =
         reinterpret_cast<const CentralDirectoryRecord*>(ptr);
     if (cdr->record_signature != CentralDirectoryRecord::kSignature) {
@@ -393,11 +401,6 @@ static int32_t ParseZipArchive(ZipArchive* archive) {
       return -1;
     }
 
-    if (ptr + sizeof(CentralDirectoryRecord) > cd_end) {
-      ALOGW("Zip: ran off the end (at %" PRIu16 ")", i);
-      return -1;
-    }
-
     const off64_t local_header_offset = cdr->local_file_header_offset;
     if (local_header_offset >= archive->directory_offset) {
       ALOGW("Zip: bad LFH offset %" PRId64 " at entry %" PRIu16,