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Commit a8d932f2 authored by Tianjie Xu's avatar Tianjie Xu
Browse files

Do Not Merge: Fix out of bound read in libziparchive 

We should check the boundary of central directory before checking its
signature. Swap the order of these two checks.

Bug: 36392138
Test: libziparchive doesn't read the signature after boundary check fails.
Change-Id: Ie89f709bb2d1ccb647116fb7ccb1e23c943e5ab8
(cherry picked from commit 74464a13)
parent 7e21e1ef

libziparchive/zip_archive.cc

+8 −5
Original line number Diff line number Diff line
@@ -622,6 +622,14 @@ 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

      goto bail;

    }



    const CentralDirectoryRecord* cdr =

        reinterpret_cast<const CentralDirectoryRecord*>(ptr);

    if (cdr->record_signature != CentralDirectoryRecord::kSignature) {
@@ -629,11 +637,6 @@ static int32_t ParseZipArchive(ZipArchive* archive) { 
      goto bail;

    }



    if (ptr + sizeof(CentralDirectoryRecord) > cd_end) {

      ALOGW("Zip: ran off the end (at %" PRIu16 ")", i);

      goto bail;

    }



    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, (int64_t)local_header_offset, i);