Unpad Valid PKCS#7

unpad_valid_pkcs7.py

def unpad_valid_pkcs7(buffer):
    padding = buffer[-1]
    for i in range(len(buffer)-1, len(buffer)-padding, -1):
        if buffer[i] != buffer[-1]:
            raise Exception("Bad PKCS#7 padding.")
    new_buffer = bytearray()
    new_buffer[:] = buffer[:-padding]
    return new_buffer

unpad_valid_pkcs7(bytearray("ICE ICE BABY\x04\x04\x04\x03"))
Traceback (most recent call last):
  File "15.py", line 10, in <module>
    print unpad_valid_pkcs7(bytearray("ICE ICE BABY\x04\x04\x04\x03"))
  File "15.py", line 5, in unpad_valid_pkcs7
    raise Exception("Bad PKCS#7 padding.")
Exception: Bad PKCS#7 padding.