added zipfix

README.md

@@ -1,2 +1,10 @@
 # zipfix
 Fix zip files with broken central directory
+
+Most of the code is taken from https://github.com/ejrh/ejrh/blob/master/utils/zipfix.py
+
+Added support for data descriptor
+
+# Usage
+
+`zipfix.py file.zip`

zipfix.py

@@ -0,0 +1,137 @@
+# This files contains code from https://github.com/ejrh/ejrh/blob/master/utils/zipfix.py
+
+import zipfile
+import struct
+import sys
+import os
+
+data_descriptor = False
+skip_size_check = False
+
+structDataDescriptor = b"<4sL2L"
+stringDataDescriptor = b"PK\x07\x08"
+sizeDataDescriptor = struct.calcsize(structDataDescriptor)
+
+_DD_SIGNATURE = 0
+_DD_CRC = 1
+_DD_COMPRESSED_SIZE = 2
+_DD_UNCOMPRESSED_SIZE = 3
+
+def write_data(filename, data):
+    if filename.endswith(b'/'):
+        os.mkdir(filename)
+    else:
+        f = open(filename, 'wb')
+        f.write(data)
+        f.close()
+
+def fdescriptor_reader(file, initial_offset=zipfile.sizeFileHeader):
+    offset = initial_offset
+    file.seek(offset)
+    while True:
+        temp = file.read(1024)
+        if len(temp) < 1024:
+            print('Found end of file.  Some entries missed.')
+            return None
+
+        parts = temp.split(stringDataDescriptor)
+        if len(parts) > 1:
+            offset += len(parts[0])
+            break
+        else:
+            offset += 1024
+    file.seek(offset)
+
+    ddescriptor = file.read(sizeDataDescriptor)
+    if len(ddescriptor) < sizeDataDescriptor:
+        print('Found end of file.  Some entries missed.')
+        return None
+
+    ddescriptor = struct.unpack(structDataDescriptor, ddescriptor)
+    if ddescriptor[_DD_SIGNATURE] != stringDataDescriptor:
+        print('Error reading data descriptor.')
+        return None
+
+    file.seek(initial_offset)
+    return ddescriptor
+
+
+def main(filename):
+    print('Reading %s Central Directory' % filename)
+
+    # Get info from ZIP Central Directory
+    with zipfile.ZipFile(filename, 'r') as myzip:
+        files = myzip.namelist()
+        print('Found %d file(s) from Central Directory:' % (len(files)))
+        print('- '+'\n- '.join(files))
+
+    print('Reading %s ZIP entry manually' % sys.argv[1])
+    f = open(filename, 'rb')
+
+    while True:
+        # Read and parse a file header
+        fheader = f.read(zipfile.sizeFileHeader)
+        if len(fheader) < zipfile.sizeFileHeader:
+            print('Found end of file.  Some entries missed.')
+            break
+
+        fheader = struct.unpack(zipfile.structFileHeader, fheader)
+        if fheader[zipfile._FH_SIGNATURE] == zipfile.stringCentralDir:
+            print('Found start of central directory.  All entries processed.')
+            break
+
+        if fheader[zipfile._FH_SIGNATURE] != zipfile.stringFileHeader:
+            raise Exception('Size mismatch! File Header expected, got "%s"' % (fheader[zipfile._FH_SIGNATURE]))
+
+        if fheader[zipfile._FH_GENERAL_PURPOSE_FLAG_BITS] & 0x8:
+            data_descriptor = True
+
+        fname = f.read(fheader[zipfile._FH_FILENAME_LENGTH])
+        if fheader[zipfile._FH_EXTRA_FIELD_LENGTH]:
+            f.read(fheader[zipfile._FH_EXTRA_FIELD_LENGTH])
+        print('Found %s' % fname.decode())
+
+        # Fake a zipinfo record
+        zi = zipfile.ZipInfo()
+        zi.filename = fname
+        zi.compress_size = fheader[zipfile._FH_COMPRESSED_SIZE]
+        zi.compress_type = fheader[zipfile._FH_COMPRESSION_METHOD]
+        zi.flag_bits = fheader[zipfile._FH_GENERAL_PURPOSE_FLAG_BITS]
+        zi.file_size = fheader[zipfile._FH_UNCOMPRESSED_SIZE]
+        zi.CRC = fheader[zipfile._FH_CRC]
+
+        if data_descriptor:
+            # Compress size is zero
+            # Get the real sizes with datadescriptor
+            ddescriptor = fdescriptor_reader(f, f.tell())
+            if ddescriptor is None:
+                break
+            zi.compress_size = ddescriptor[_DD_COMPRESSED_SIZE]
+            zi.file_size = ddescriptor[_DD_UNCOMPRESSED_SIZE]
+            zi.CRC = ddescriptor[_DD_CRC]
+
+        #print(zi)
+
+        # Read the file contents
+        zef = zipfile.ZipExtFile(f, 'rb', zi)
+        data = zef.read()
+
+        # Sanity checks
+        if len(data) != zi.file_size:
+            raise Exception("Unzipped data doesn't match expected size! %d != %d, in %s" % (len(data), zi.file_size, fname))
+        calc_crc = zipfile.crc32(data) & 0xffffffff
+        if calc_crc != zi.CRC:
+            raise Exception('CRC mismatch! %d != %d, in %s' % (calc_crc, zi.CRC, fname))
+
+        # Write the file
+        write_data(fname, data)
+
+        if data_descriptor:
+            # skip dataDescriptor before reading the next file
+            f.seek(f.tell()+sizeDataDescriptor)
+
+    f.close()
+
+if __name__ == '__main__':
+    main(sys.argv[1])
+