Re: [PATCH v2] archive-zip: Add zip64 headers when file size is too large for 32 bits
From: Johannes Sixt <hidden>
Date: 2017-04-23 07:50:24
Am 23.04.2017 um 00:41 schrieb Peter Krefting:
Indeed. Last time I implemented zip64 support it was on the reading side, and I remember this was a mess...
It is indeed!
static void set_zip_header_data_desc(struct zip_local_header *header,
unsigned long size,
unsigned long compressed_size,
- unsigned long crc)
+ unsigned long crc,
+ int *clamped)
{
copy_le32(header->crc32, crc);
- copy_le32(header->compressed_size, compressed_size);
- copy_le32(header->size, size);
+ copy_le32(header->compressed_size, clamp_max(compressed_size, 0xFFFFFFFFU, clamped));
+ copy_le32(header->size, clamp_max(size, 0xFFFFFFFFU, clamped));
+ if (clamped)
+ zip_zip64 = 1;This must be if (*clamped)
quoted hunk ↗ jump to hunk
} static int has_only_ascii(const char *s)@@ -279,6 +299,7 @@ static int write_zip_entry(struct archiver_args *args, int is_binary = -1; const char *path_without_prefix = path + args->baselen; unsigned int creator_version = 0; + int clamped = 0; crc = crc32(0, NULL, 0);@@ -376,7 +397,7 @@ static int write_zip_entry(struct archiver_args *args, copy_le16(dirent.comment_length, 0); copy_le16(dirent.disk, 0); copy_le32(dirent.attr2, attr2); - copy_le32(dirent.offset, zip_offset); + copy_le32(dirent.offset, clamp_max(zip_offset, 0xFFFFFFFFU, &clamped));
I don't see any provisions to write the zip64 extra header in the central directory when this offset is clamped. This means that ZIP archives whose size exceed 4GB are still unsupported.
quoted hunk ↗ jump to hunk
copy_le32(header.magic, 0x04034b50); copy_le16(header.version, 10);@@ -384,15 +405,26 @@ static int write_zip_entry(struct archiver_args *args, copy_le16(header.compression_method, method); copy_le16(header.mtime, zip_time); copy_le16(header.mdate, zip_date); - set_zip_header_data_desc(&header, size, compressed_size, crc); + set_zip_header_data_desc(&header, size, compressed_size, crc, &clamped); copy_le16(header.filename_length, pathlen); - copy_le16(header.extra_length, ZIP_EXTRA_MTIME_SIZE); + copy_le16(header.extra_length, ZIP_EXTRA_MTIME_SIZE + (clamped ? ZIP_EXTRA_ZIP64_SIZE : 0)); write_or_die(1, &header, ZIP_LOCAL_HEADER_SIZE); zip_offset += ZIP_LOCAL_HEADER_SIZE; write_or_die(1, path, pathlen); zip_offset += pathlen; write_or_die(1, &extra, ZIP_EXTRA_MTIME_SIZE); zip_offset += ZIP_EXTRA_MTIME_SIZE; + if (clamped) { + struct zip_extra_zip64 extra_zip64; + copy_le16(extra_zip64.magic, 0x0001); + copy_le16(extra_zip64.extra_size, ZIP_EXTRA_ZIP64_PAYLOAD_SIZE); + copy_le64(extra_zip64.size, size >= 0xFFFFFFFFU ? size : 0); + copy_le64(extra_zip64.compressed_size, compressed_size >= 0xFFFFFFFFU ? compressed_size : 0); + copy_le64(extra_zip64.offset, zip_offset >= 0xFFFFFFFFU ? zip_offset : 0); + copy_le32(extra_zip64.disk, 0);
These are wrong, I think. Entries that did not overflow must be omitted entirely from the zip64 extra record, not filled with 0. This implies that the payload size (.extra_size) is dynamic. As René pointed out, the offset is only written in the central directory, but not in the local header for the current file. Therefore, it must be omitted here. The disk number also never exceeds 0xffff and must be omitted as well.
quoted hunk ↗ jump to hunk
+ write_or_die(1, &extra_zip64, ZIP_EXTRA_ZIP64_SIZE); + zip_offset += ZIP_EXTRA_ZIP64_SIZE; + } if (stream && method == 0) { unsigned char buf[STREAM_BUFFER_SIZE]; ssize_t readlen;@@ -538,7 +570,7 @@ static void write_zip_trailer(const unsigned char *sha1) copy_le16(trailer.comment_length, sha1 ? GIT_SHA1_HEXSZ : 0); write_or_die(1, zip_dir, zip_dir_offset); - if (clamped) + if (clamped || zip_zip64) write_zip64_trailer(); write_or_die(1, &trailer, ZIP_DIR_TRAILER_SIZE); if (sha1)
-- Hannes