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Improve key detection

This commit is contained in:
NoDRM 2021-11-15 11:59:56 +01:00
parent 95fc924d1a
commit 969fe52e13
3 changed files with 105 additions and 7 deletions
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46
DeDRM_plugin/__init__.py
View File

@ -317,7 +317,41 @@ class DeDRM(FileTypePlugin):
import calibre_plugins.dedrm.ineptepub as ineptepub
if ineptepub.adeptBook(inf.name):
print("{0} v{1}: {2} is a secure Adobe Adept ePub".format(PLUGIN_NAME, PLUGIN_VERSION, os.path.basename(path_to_ebook)))
book_uuid = None
try:
# This tries to figure out which Adobe account UUID the book is licensed for.
# If we know that we can directly use the correct key instead of having to
# try them all.
book_uuid = ineptepub.adeptGetUserUUID(inf.name)
except:
pass
if book_uuid is None:
print("{0} v{1}: {2} is a secure Adobe Adept ePub".format(PLUGIN_NAME, PLUGIN_VERSION, os.path.basename(path_to_ebook)))
else:
print("{0} v{1}: {2} is a secure Adobe Adept ePub for UUID {3}".format(PLUGIN_NAME, PLUGIN_VERSION, os.path.basename(path_to_ebook), book_uuid))
if book_uuid is not None:
# Check if we have a key with that UUID in its name:
for keyname, userkeyhex in dedrmprefs['adeptkeys'].items():
if not book_uuid.lower() in keyname.lower():
continue
# Found matching key
userkey = codecs.decode(userkeyhex, 'hex')
print("{0} v{1}: Trying UUID-matched encryption key {2:s}".format(PLUGIN_NAME, PLUGIN_VERSION, keyname))
of = self.temporary_file(".epub")
try:
result = ineptepub.decryptBook(userkey, inf.name, of.name)
of.close()
if result == 0:
print("{0} v{1}: Decrypted with key {2:s} after {3:.1f} seconds".format(PLUGIN_NAME, PLUGIN_VERSION,keyname,time.time()-self.starttime))
return of.name
except:
print("{0} v{1}: Exception when decrypting after {2:.1f} seconds - trying other keys".format(PLUGIN_NAME, PLUGIN_VERSION, time.time()-self.starttime))
traceback.print_exc()
# Attempt to decrypt epub with each encryption key (generated or provided).
for keyname, userkeyhex in dedrmprefs['adeptkeys'].items():
@ -363,7 +397,10 @@ class DeDRM(FileTypePlugin):
scriptpath = os.path.join(self.alfdir,"adobekey.py")
defaultkeys, defaultnames = WineGetKeys(scriptpath, ".der",dedrmprefs['adobewineprefix'])
self.default_key = defaultkeys[0]
try:
self.default_key = defaultkeys[0]
except:
print("{0} v{1}: No ADE key found".format(PLUGIN_NAME, PLUGIN_VERSION))
except:
print("{0} v{1}: Exception when getting default Adobe Key after {2:.1f} seconds".format(PLUGIN_NAME, PLUGIN_VERSION, time.time()-self.starttime))
traceback.print_exc()
@ -470,7 +507,10 @@ class DeDRM(FileTypePlugin):
scriptpath = os.path.join(self.alfdir,"adobekey.py")
defaultkeys, defaultnames = WineGetKeys(scriptpath, ".der",dedrmprefs['adobewineprefix'])
self.default_key = defaultkeys[0]
try:
self.default_key = defaultkeys[0]
except:
print("{0} v{1}: No ADE key found".format(PLUGIN_NAME, PLUGIN_VERSION))
except:
print("{0} v{1}: Exception when getting default Adobe Key after {2:.1f} seconds".format(PLUGIN_NAME, PLUGIN_VERSION, time.time()-self.starttime))
traceback.print_exc()

38
DeDRM_plugin/ineptepub.py
View File

@ -393,6 +393,42 @@ def adeptBook(inpath):
return True
return False
# Checks the license file and returns the UUID the book is licensed for.
# This is used so that the Calibre plugin can pick the correct decryption key
# first try without having to loop through all possible keys.
def adeptGetUserUUID(inpath):
with closing(ZipFile(open(inpath, 'rb'))) as inf:
try:
rights = etree.fromstring(inf.read('META-INF/rights.xml'))
adept = lambda tag: '{%s}%s' % (NSMAP['adept'], tag)
expr = './/%s' % (adept('user'),)
user_uuid = ''.join(rights.findtext(expr))
if user_uuid[:9] != "urn:uuid:":
return None
return user_uuid[9:]
except:
return None
def verify_book_key(bookkey):
if bookkey[-17] != '\x00' and bookkey[-17] != 0:
# Byte not null, invalid result
return False
if ((bookkey[0] != '\x02' and bookkey[0] != 2) and
((bookkey[0] != '\x00' and bookkey[0] != 0) or
(bookkey[1] != '\x02' and bookkey[1] != 2))):
# Key not starting with "00 02" or "02" -> error
return False
keylen = len(bookkey) - 17
for i in range(1, keylen):
if bookkey[i] == 0 or bookkey[i] == '\x00':
# Padding data contains a space - that's not allowed.
# Probably bad decryption.
return False
return True
def decryptBook(userkey, inpath, outpath):
if AES is None:
raise ADEPTError("PyCrypto or OpenSSL must be installed.")
@ -416,7 +452,7 @@ def decryptBook(userkey, inpath, outpath):
bookkey = rsa.decrypt(codecs.decode(bookkey.encode('ascii'), 'base64'))
# Padded as per RSAES-PKCS1-v1_5
if len(bookkey) > 16:
if bookkey[-17] == '\x00' or bookkey[-17] == 0:
if verify_book_key(bookkey):
bookkey = bookkey[-16:]
else:
print("Could not decrypt {0:s}. Wrong key".format(os.path.basename(inpath)))

28
DeDRM_plugin/ineptpdf.py
View File

@ -1587,6 +1587,26 @@ class PDFDocument(object):
self.ready = True
return
def verify_book_key(self, bookkey):
if bookkey[-17] != '\x00' and bookkey[-17] != 0:
# Byte not null, invalid result
return False
if ((bookkey[0] != '\x02' and bookkey[0] != 2) and
((bookkey[0] != '\x00' and bookkey[0] != 0) or
(bookkey[1] != '\x02' and bookkey[1] != 2))):
# Key not starting with "00 02" or "02" -> error
return False
keylen = len(bookkey) - 17
for i in range(1, keylen):
if bookkey[i] == 0 or bookkey[i] == '\x00':
# Padding data contains a space - that's not allowed.
# Probably bad decryption.
return False
return True
def initialize_ebx(self, password, docid, param):
self.is_printable = self.is_modifiable = self.is_extractable = True
rsa = RSA(password)
@ -1597,12 +1617,14 @@ class PDFDocument(object):
expr = './/{http://ns.adobe.com/adept}encryptedKey'
bookkey = codecs.decode(''.join(rights.findtext(expr)).encode('utf-8'),'base64')
bookkey = rsa.decrypt(bookkey)
#if bookkey[0] != 2:
# raise ADEPTError('error decrypting book session key')
if len(bookkey) > 16:
if bookkey[-17] == '\x00' or bookkey[-17] == 0:
if (self.verify_book_key(bookkey)):
bookkey = bookkey[-16:]
length = 16
else:
raise ADEPTError('error decrypting book session key')
ebx_V = int_value(param.get('V', 4))
ebx_type = int_value(param.get('EBX_ENCRYPTIONTYPE', 6))
# added because of improper booktype / decryption book session key errors