TPM1.2 hashing with just the device node

tpm1_hash.py

#!/usr/bin/env python

import binascii
import struct
import logging

logger = logging.getLogger()
#logger.setLevel(logging.DEBUG)

TPM_TAG_RQU_COMMAND = 0x00C1

TPM_ORD_SHA1Start = 0x000000A0
TPM_ORD_SHA1Complete = 0x000000A2


def main():

    str = "The quick brown fox jumps over the lazy dog"
    print "SHA-1 hash of the string: " + str

    try:
        f = open('/dev/tpm0', 'r+b')
    except IOError, e:
        logging.error('Error opening the device %s: \n%r' %
            ('/dev/tpm0', e))
        raise SystemExit(1)

## SHA1Start
    fmt = '>HII'
    cmd = struct.pack(fmt,
                      TPM_TAG_RQU_COMMAND,
                      struct.calcsize(fmt),
                      TPM_ORD_SHA1Start
                      )

    logging.debug('Cmd =' + binascii.hexlify(cmd[0:]))
    f.write(cmd)
    rsp = f.read()
    logging.debug('Res =' + binascii.hexlify(rsp[0:]))

## SHA1Complete
    fmt = '>HIII43s'
    cmd = struct.pack(fmt,
                      TPM_TAG_RQU_COMMAND,
                      struct.calcsize(fmt),
                      TPM_ORD_SHA1Complete,
                      len(str),
                      str
                      )

    logging.debug('Cmd =' + binascii.hexlify(cmd[0:]))
    f.write(cmd)
    rsp = f.read()
    logging.debug('Res =' + binascii.hexlify(rsp[0:]))

    print('Hash=' + binascii.hexlify(rsp[10:]))

    f.close()

if __name__ == "__main__":
    main()