build: implement zip64 stripping (#22998)
When zip contains files larger than 4GB 4bytes length headers are not sufficient anymore. Zip64 defines an extra header 0x0001 which may contain 8byte lengthed (16 exabytes) lengths [uncompressed and compressed]. Read this value when performing extra data cleaning and override the bogus value if the header is available. Read https://blog.yaakov.online/zip64-go-big-or-go-home/ for more information on Zip64 extra header. This is the first known implementation of zip64 stripping.
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Родитель
f4cf23f6ac
Коммит
ff21444429
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@ -182,7 +182,7 @@ def zero_zip_date_time(fname):
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def _zero_zip_date_time(zip_):
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def purify_extra_data(mm, offset, length):
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def purify_extra_data(mm, offset, length, compressed_size=0):
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extra_header_struct = Struct("<HH")
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# 0. id
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# 1. length
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@ -194,6 +194,16 @@ def _zero_zip_date_time(zip_):
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UNIX_EXTRA_DATA = 0x7875
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# Unix extra data; UID / GID stuff, see
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# ftp://ftp.info-zip.org/pub/infozip/src/zip30.zip ./proginfo/extrafld.txt
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ZIP64_EXTRA_HEADER = 0x0001
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zip64_extra_struct = Struct("<HHQQ")
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# ZIP64.
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# When a ZIP64 extra field is present his 8byte length
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# will override the 4byte length defined in canonical zips.
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# This is in the form:
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# - 0x0001 (header_id)
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# - 0x0010 [16] (header_length)
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# - ... (8byte uncompressed_length)
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# - ... (8byte compressed_length)
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mlen = offset + length
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while offset < mlen:
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@ -205,15 +215,17 @@ def _zero_zip_date_time(zip_):
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if header_id in (EXTENDED_TIME_DATA, UNIX_EXTRA_DATA):
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values[0] = STRIPZIP_OPTION_HEADER
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for i in xrange(2, len(values)):
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for i in range(2, len(values)):
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values[i] = 0xff
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extra_struct.pack_into(mm, offset, *values)
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elif header_id != STRIPZIP_OPTION_HEADER:
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return False
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if header_id == ZIP64_EXTRA_HEADER:
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assert header_length == 16
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values = list(zip64_extra_struct.unpack_from(mm, offset))
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header_id, header_length, uncompressed_size, compressed_size = values
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offset += extra_header_struct.size + header_length
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return True
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return compressed_size
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FILE_HEADER_SIGNATURE = 0x04034b50
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CENDIR_HEADER_SIGNATURE = 0x02014b50
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@ -263,9 +275,10 @@ def _zero_zip_date_time(zip_):
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# reset last_mod_date
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values[5] = 0x21
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local_file_header_struct.pack_into(mm, offset, *values)
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offset += local_file_header_struct.size + compressed_size + name_length + extra_field_length
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offset += local_file_header_struct.size + name_length
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if extra_field_length != 0:
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purify_extra_data(mm, offset - extra_field_length - compressed_size, extra_field_length)
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compressed_size = purify_extra_data(mm, offset, extra_field_length, compressed_size)
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offset += compressed_size + extra_field_length
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while offset < archive_size:
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if signature_struct.unpack_from(mm, offset) != (CENDIR_HEADER_SIGNATURE,):
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