tcheck all bytes in strip_pkcs7_padding - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
DIR Log
DIR Files
DIR Refs
DIR Submodules
---
DIR commit cc71dfea863cce0a1f497a8524141e76cad824e2
DIR parent de1123e4a04933867908e19b61dbec8000a65947
HTML Author: ThomasV <thomasv@gitorious>
Date: Mon, 1 Sep 2014 15:37:38 +0200
check all bytes in strip_pkcs7_padding
Diffstat:
M lib/bitcoin.py | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
---
DIR diff --git a/lib/bitcoin.py b/lib/bitcoin.py
t@@ -45,6 +45,17 @@ MIN_RELAY_TX_FEE = 1000
EncodeAES = lambda secret, s: base64.b64encode(aes.encryptData(secret,s))
DecodeAES = lambda secret, e: aes.decryptData(secret, base64.b64decode(e))
+def strip_PKCS7_padding(s):
+ """return s stripped of PKCS7 padding"""
+ if len(s)%16 or not s:
+ raise ValueError("String of len %d can't be PCKS7-padded" % len(s))
+ numpads = ord(s[-1])
+ if numpads > 16:
+ raise ValueError("String ending with %r can't be PCKS7-padded" % s[-1])
+ if s[-numpads:] != numpads*chr(numpads):
+ raise ValueError("Invalid PKCS7 padding")
+ return s[:-numpads]
+
def aes_encrypt_with_iv(key, iv, data):
mode = aes.AESModeOfOperation.modeOfOperation["CBC"]
t@@ -66,7 +77,7 @@ def aes_decrypt_with_iv(key, iv, data):
data = map(ord, data)
moo = aes.AESModeOfOperation()
decr = moo.decrypt(data, None, mode, key, keysize, iv)
- decr = aes.strip_PKCS7_padding(decr)
+ decr = strip_PKCS7_padding(decr)
return decr