[Python-checkins] r60121 - in python/trunk/Lib: test/test_zipfile.py zipfile.py

[gregory.p.smith]

Author: gregory.p.smith
Date: Sun Jan 20 02:21:03 2008
New Revision: 60121

Modified:
   python/trunk/Lib/test/test_zipfile.py
   python/trunk/Lib/zipfile.py
Log:
Fix zipfile decryption.  The check for validity only worked on one
type of encrypted zip files.  Files using extended local headers
needed to compare the check byte against different values.  (according
to reading the infozip unzip crypt.c source code)

Fixes issue1003.


Modified: python/trunk/Lib/test/test_zipfile.py
==============================================================================
--- python/trunk/Lib/test/test_zipfile.py	(original)
+++ python/trunk/Lib/test/test_zipfile.py	Sun Jan 20 02:21:03 2008
@@ -698,31 +698,52 @@
     '\x1a\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x01\x00 \x00\xb6\x81'
     '\x00\x00\x00\x00test.txtPK\x05\x06\x00\x00\x00\x00\x01\x00\x01\x006\x00'
     '\x00\x00L\x00\x00\x00\x00\x00' )
+    data2 = (
+    'PK\x03\x04\x14\x00\t\x00\x08\x00\xcf}38xu\xaa\xb2\x14\x00\x00\x00\x00\x02'
+    '\x00\x00\x04\x00\x15\x00zeroUT\t\x00\x03\xd6\x8b\x92G\xda\x8b\x92GUx\x04'
+    '\x00\xe8\x03\xe8\x03\xc7<M\xb5a\xceX\xa3Y&\x8b{oE\xd7\x9d\x8c\x98\x02\xc0'
+    'PK\x07\x08xu\xaa\xb2\x14\x00\x00\x00\x00\x02\x00\x00PK\x01\x02\x17\x03'
+    '\x14\x00\t\x00\x08\x00\xcf}38xu\xaa\xb2\x14\x00\x00\x00\x00\x02\x00\x00'
+    '\x04\x00\r\x00\x00\x00\x00\x00\x00\x00\x00\x00\xa4\x81\x00\x00\x00\x00ze'
+    'roUT\x05\x00\x03\xd6\x8b\x92GUx\x00\x00PK\x05\x06\x00\x00\x00\x00\x01'
+    '\x00\x01\x00?\x00\x00\x00[\x00\x00\x00\x00\x00' )
 
     plain = 'zipfile.py encryption test'
+    plain2 = '\x00'*512
 
     def setUp(self):
         fp = open(TESTFN, "wb")
         fp.write(self.data)
         fp.close()
         self.zip = zipfile.ZipFile(TESTFN, "r")
+        fp = open(TESTFN2, "wb")
+        fp.write(self.data2)
+        fp.close()
+        self.zip2 = zipfile.ZipFile(TESTFN2, "r")
 
     def tearDown(self):
         self.zip.close()
         os.unlink(TESTFN)
+        self.zip2.close()
+        os.unlink(TESTFN2)
 
     def testNoPassword(self):
         # Reading the encrypted file without password
         # must generate a RunTime exception
         self.assertRaises(RuntimeError, self.zip.read, "test.txt")
+        self.assertRaises(RuntimeError, self.zip2.read, "zero")
 
     def testBadPassword(self):
         self.zip.setpassword("perl")
         self.assertRaises(RuntimeError, self.zip.read, "test.txt")
+        self.zip2.setpassword("perl")
+        self.assertRaises(RuntimeError, self.zip2.read, "zero")
 
     def testGoodPassword(self):
         self.zip.setpassword("python")
         self.assertEquals(self.zip.read("test.txt"), self.plain)
+        self.zip2.setpassword("12345")
+        self.assertEquals(self.zip2.read("zero"), self.plain2)
 
 
 class TestsWithRandomBinaryFiles(unittest.TestCase):

Modified: python/trunk/Lib/zipfile.py
==============================================================================
--- python/trunk/Lib/zipfile.py	(original)
+++ python/trunk/Lib/zipfile.py	Sun Jan 20 02:21:03 2008
@@ -186,6 +186,7 @@
             'CRC',
             'compress_size',
             'file_size',
+            '_raw_time',
         )
 
     def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
@@ -683,6 +684,7 @@
                 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 )
 
@@ -790,11 +792,18 @@
             # 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 = map(zd, bytes[0:12])
-            if ord(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 ord(h[11]) != check_byte:
+                raise RuntimeError("Bad password for file", name)
 
         # build and return a ZipExtFile
         if zd is None: