diff options
Diffstat (limited to 'Lib/zipfile.py')
| -rw-r--r-- | Lib/zipfile.py | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/Lib/zipfile.py b/Lib/zipfile.py index 9f98728..2865c0a 100644 --- a/Lib/zipfile.py +++ b/Lib/zipfile.py @@ -34,9 +34,9 @@ ZIP_DEFLATED = 8 # Other ZIP compression methods not supported # Here are some struct module formats for reading headers -structEndArchive = "<4s4H2lH" # 9 items, end of archive, 22 bytes +structEndArchive = "<4s4H2LH" # 9 items, end of archive, 22 bytes stringEndArchive = b"PK\005\006" # magic number for end of archive record -structCentralDir = "<4s4B4HlLL5HLl"# 19 items, central directory, 46 bytes +structCentralDir = "<4s4B4HlLL5HLL"# 19 items, central directory, 46 bytes stringCentralDir = b"PK\001\002" # magic number for central directory structFileHeader = "<4s2B4HlLL2H" # 12 items, file header record, 30 bytes stringFileHeader = b"PK\003\004" # magic number for file header @@ -188,6 +188,7 @@ class ZipInfo (object): 'CRC', 'compress_size', 'file_size', + '_raw_time', ) def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)): @@ -303,7 +304,7 @@ class _ZipDecrypter: ZIP supports a password-based form of encryption. Even though known plaintext attacks have been found against it, it is still useful - for low-level securicy. + to be able to get data out of such a file. Usage: zd = _ZipDecrypter(mypwd) @@ -690,6 +691,7 @@ class ZipFile: x.CRC, x.compress_size, x.file_size) = centdir[1:12] x.volume, x.internal_attr, x.external_attr = centdir[15:18] # Convert date/time code to (year, month, day, hour, min, sec) + x._raw_time = t x.date_time = ( (d>>9)+1980, (d>>5)&0xF, d&0x1F, t>>11, (t>>5)&0x3F, (t&0x1F) * 2 ) @@ -800,11 +802,18 @@ class ZipFile: # The first 12 bytes in the cypher stream is an encryption header # used to strengthen the algorithm. The first 11 bytes are # completely random, while the 12th contains the MSB of the CRC, + # or the MSB of the file time depending on the header type # and is used to check the correctness of the password. bytes = zef_file.read(12) h = list(map(zd, bytes[0:12])) - if h[11] != ((zinfo.CRC>>24) & 255): - raise RuntimeError("Bad password for file %s" % name) + if zinfo.flag_bits & 0x8: + # compare against the file type from extended local headers + check_byte = (zinfo._raw_time >> 8) & 0xff + else: + # compare against the CRC otherwise + check_byte = (zinfo.CRC >> 24) & 0xff + if h[11] != check_byte: + raise RuntimeError("Bad password for file", name) # build and return a ZipExtFile if zd is None: |