[Libreoffice-commits] .: src/msocrypto.py xls-dump.py

[Kohei Yoshida]

 src/msocrypto.py |   75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 xls-dump.py      |    8 +++++
 2 files changed, 83 insertions(+)

New commits:
commit 6dcfa7596d5b721b46787cd1d7b0ddb3a1e26105
Author: Kohei Yoshida <kohei.yoshida at gmail.com>
Date:   Mon Dec 17 17:11:12 2012 -0500

    Dump EncryptionInfo directory which stores info about encrypted documents.
    
    This is true even for the OOXML-based file formats.

diff --git a/src/msocrypto.py b/src/msocrypto.py
new file mode 100644
index 0000000..c264d54
--- /dev/null
+++ b/src/msocrypto.py
@@ -0,0 +1,75 @@
+########################################################################
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+########################################################################
+
+import globals
+
+class EncryptionInfo(object):
+
+    class Type:
+        Unknown = -1
+        Standard = 0
+        Extensible = 1
+        Agile = 2
+
+    def __init__ (self, bytes):
+        self.strm = globals.ByteStream(bytes)
+        self.type = EncryptionInfo.Type.Unknown
+        self.size = -1
+
+    def read (self):
+        self.major = self.strm.readUnsignedInt(2)
+        self.minor = self.strm.readUnsignedInt(2)
+
+        if self.major == 3 or self.major == 4:
+            if self.minor == 2:
+                self.type = EncryptionInfo.Type.Standard
+            elif self.minor == 3:
+                self.type = EncryptionInfo.Type.Extensible
+            elif self.minor == 4:
+                self.type = EncryptionInfo.Type.Agile
+
+        flag = self.strm.readUnsignedInt(4)
+        self.fCryptoAPI = (flag & 0x00000004) != 0 # C
+        self.fDocProps  = (flag & 0x00000008) != 0 # D (false if document properties are encrypted.)
+        self.fExternal  = (flag & 0x00000010) != 0 # E (extensible encryption used)
+        self.fAES       = (flag & 0x00000020) != 0 # F (ECMA-376 document)
+
+        if self.type == EncryptionInfo.Type.Standard or self.type == EncryptionInfo.Type.Extensible:
+            self.size = self.strm.readUnsignedInt(4)
+
+    def outputBoolean (self, name, value):
+        if value:
+            bs = "true"
+        else:
+            bs = "false"
+        print ("%s: %s"%(name, bs))
+
+    def outputInt (self, name, value):
+        print ("%s: %d"%(name, value))
+
+    def output (self):
+        print ("version: %d.%d"%(self.major, self.minor))
+        self.outputBoolean("crypto API", self.fCryptoAPI)
+        self.outputBoolean("encrypted document properties", not self.fDocProps)
+        self.outputBoolean("extensible encryption", self.fExternal)
+        self.outputBoolean("ECMA-376 document", self.fAES)
+        if self.type == EncryptionInfo.Type.Standard:
+            self.outputStandard()
+        elif self.type == EncryptionInfo.Type.Extensible:
+            self.outputExtensible()
+        elif self.type == EncryptionInfo.Type.Agile:
+            self.outputAgile()
+
+    def outputStandard (self):
+        self.outputInt("header stream size", self.size)
+
+    def outputExtensible (self):
+        self.outputInt("header stream size", self.size)
+
+    def outputAgile (self):
+        pass
diff --git a/xls-dump.py b/xls-dump.py
index 75e333e..0b7a7f6 100755
--- a/xls-dump.py
+++ b/xls-dump.py
@@ -30,6 +30,7 @@ import sys, os.path, optparse
 sys.path.append(sys.path[0]+"/src")
 import ole, xlsstream, globals, node, xlsmodel, olestream
 import xlsparser
+import msocrypto
 
 from globals import error
 
@@ -143,6 +144,13 @@ class XLDumper(object):
                 dirstrm.type = xlsstream.DirType.RevisionLog
                 self.__readSubStream(dirstrm)
 
+            elif dirname == "EncryptionInfo":
+                globals.dumpBytes(dirstrm.bytes, 512)
+                print("-"*globals.OutputWidth)
+                info = msocrypto.EncryptionInfo(dirstrm.bytes)
+                info.read()
+                info.output()
+
             elif self.strmData.isPivotCacheStream(dirname):
                 dirstrm.type = xlsstream.DirType.PivotTableCache
                 self.__readSubStream(dirstrm)