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Support Zip archives not starting at zero offset #309

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merged 1 commit into from
Jun 9, 2024
Merged

Support Zip archives not starting at zero offset #309

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77 changes: 65 additions & 12 deletions miniz_zip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -647,10 +647,23 @@ static int mz_stat64(const char *path, struct __stat64 *buffer)
return MZ_TRUE;
}

static mz_bool mz_zip_reader_eocd64_valid(mz_zip_archive *pZip, uint64_t offset, uint8_t *buf)
{
if (pZip->m_pRead(pZip->m_pIO_opaque, offset, buf, MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE) == MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE)
{
if (MZ_READ_LE32(buf + MZ_ZIP64_ECDH_SIG_OFS) == MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIG)
{
return MZ_TRUE;
}
}

return MZ_FALSE;
}

static mz_bool mz_zip_reader_read_central_dir(mz_zip_archive *pZip, mz_uint flags)
{
mz_uint cdir_size = 0, cdir_entries_on_this_disk = 0, num_this_disk = 0, cdir_disk_index = 0;
mz_uint64 cdir_ofs = 0;
mz_uint64 cdir_ofs = 0, eocd_ofs = 0, archive_ofs = 0;
mz_int64 cur_file_ofs = 0;
const mz_uint8 *p;

Expand All @@ -672,6 +685,7 @@ static int mz_stat64(const char *path, struct __stat64 *buffer)
if (!mz_zip_reader_locate_header_sig(pZip, MZ_ZIP_END_OF_CENTRAL_DIR_HEADER_SIG, MZ_ZIP_END_OF_CENTRAL_DIR_HEADER_SIZE, &cur_file_ofs))
return mz_zip_set_error(pZip, MZ_ZIP_FAILED_FINDING_CENTRAL_DIR);

eocd_ofs = cur_file_ofs;
/* Read and verify the end of central directory record. */
if (pZip->m_pRead(pZip->m_pIO_opaque, cur_file_ofs, pBuf, MZ_ZIP_END_OF_CENTRAL_DIR_HEADER_SIZE) != MZ_ZIP_END_OF_CENTRAL_DIR_HEADER_SIZE)
return mz_zip_set_error(pZip, MZ_ZIP_FILE_READ_FAILED);
Expand All @@ -685,21 +699,40 @@ static int mz_stat64(const char *path, struct __stat64 *buffer)
{
if (MZ_READ_LE32(pZip64_locator + MZ_ZIP64_ECDL_SIG_OFS) == MZ_ZIP64_END_OF_CENTRAL_DIR_LOCATOR_SIG)
{
zip64_end_of_central_dir_ofs = MZ_READ_LE64(pZip64_locator + MZ_ZIP64_ECDL_REL_OFS_TO_ZIP64_ECDR_OFS);
if (zip64_end_of_central_dir_ofs > (pZip->m_archive_size - MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE))
return mz_zip_set_error(pZip, MZ_ZIP_NOT_AN_ARCHIVE);

if (pZip->m_pRead(pZip->m_pIO_opaque, zip64_end_of_central_dir_ofs, pZip64_end_of_central_dir, MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE) == MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE)
{
if (MZ_READ_LE32(pZip64_end_of_central_dir + MZ_ZIP64_ECDH_SIG_OFS) == MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIG)
{
pZip->m_pState->m_zip64 = MZ_TRUE;
}
}
pZip->m_pState->m_zip64 = MZ_TRUE;
}
}
}

if (pZip->m_pState->m_zip64)
{
/* Try locating the EOCD64 right before the EOCD64 locator. This works even
* when the effective start of the zip header is not yet known. */
if (cur_file_ofs < MZ_ZIP64_END_OF_CENTRAL_DIR_LOCATOR_SIZE +
MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE)
return mz_zip_set_error(pZip, MZ_ZIP_NOT_AN_ARCHIVE);

zip64_end_of_central_dir_ofs = cur_file_ofs -
MZ_ZIP64_END_OF_CENTRAL_DIR_LOCATOR_SIZE -
MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE;

if (!mz_zip_reader_eocd64_valid(pZip, zip64_end_of_central_dir_ofs,
pZip64_end_of_central_dir))
{
/* That failed, try reading where the locator tells us to. */
zip64_end_of_central_dir_ofs = MZ_READ_LE64(
pZip64_locator + MZ_ZIP64_ECDL_REL_OFS_TO_ZIP64_ECDR_OFS);

if (zip64_end_of_central_dir_ofs >
(pZip->m_archive_size - MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE))
return mz_zip_set_error(pZip, MZ_ZIP_NOT_AN_ARCHIVE);

if (!mz_zip_reader_eocd64_valid(pZip, zip64_end_of_central_dir_ofs,
pZip64_end_of_central_dir))
return mz_zip_set_error(pZip, MZ_ZIP_NOT_AN_ARCHIVE);
}
}

pZip->m_total_files = MZ_READ_LE16(pBuf + MZ_ZIP_ECDH_CDIR_TOTAL_ENTRIES_OFS);
cdir_entries_on_this_disk = MZ_READ_LE16(pBuf + MZ_ZIP_ECDH_CDIR_NUM_ENTRIES_ON_DISK_OFS);
num_this_disk = MZ_READ_LE16(pBuf + MZ_ZIP_ECDH_NUM_THIS_DISK_OFS);
Expand Down Expand Up @@ -757,6 +790,26 @@ static int mz_stat64(const char *path, struct __stat64 *buffer)
if ((cdir_ofs + (mz_uint64)cdir_size) > pZip->m_archive_size)
return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);

/* The end of central dir follows the central dir, unless the zip file has
* some trailing data (e.g. it is appended to an executable file). */
archive_ofs = eocd_ofs - (cdir_ofs + cdir_size);
if (pZip->m_pState->m_zip64)
{
if (archive_ofs < MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE +
MZ_ZIP64_END_OF_CENTRAL_DIR_LOCATOR_SIZE)
return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);

archive_ofs -= MZ_ZIP64_END_OF_CENTRAL_DIR_HEADER_SIZE +
MZ_ZIP64_END_OF_CENTRAL_DIR_LOCATOR_SIZE;
}

/* Update the archive start position, but only if not specified. */
if (pZip->m_pState->m_file_archive_start_ofs == 0)
{
pZip->m_pState->m_file_archive_start_ofs = archive_ofs;
pZip->m_archive_size -= archive_ofs;
}

pZip->m_central_directory_file_ofs = cdir_ofs;

if (pZip->m_total_files)
Expand Down
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