From 0c63fc23c4ca5b859a99e0d1864a41df6cc08d5f Mon Sep 17 00:00:00 2001
From: "Gregory P. Smith" <greg@mad-scientist.com>
Date: Sun, 20 Jan 2008 01:21:03 +0000
Subject: 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.
---
 Lib/test/test_zipfile.py | 21 +++++++++++++++++++++
 Lib/zipfile.py           | 13 +++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_zipfile.py b/Lib/test/test_zipfile.py
index 40003aa..adc0dc1 100644
--- a/Lib/test/test_zipfile.py
+++ b/Lib/test/test_zipfile.py
@@ -698,31 +698,52 @@ class DecryptionTests(unittest.TestCase):
     '\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):
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index eb00b34..6feabbf 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -186,6 +186,7 @@ class ZipInfo (object):
             'CRC',
             'compress_size',
             'file_size',
+            '_raw_time',
         )
 
     def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
@@ -683,6 +684,7 @@ 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 )
 
@@ -790,11 +792,18 @@ 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 = 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:
-- 
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