Allow update_binary function to write more than 255 bytes

The T0 protocol (selected in transport/pcsc.py) does not support extended APDU, so 255 bytes is the maximum number of bytes that can be transmitted at a time.  We can divide large data into 255 byte chunks.  The read_binary function already has code to read more than 255 bytes, so we can just adapt it to the update_binary function.

Change-Id: Icc240d5c8c04198640eb118565ea99f10ba27466
changes/14/25114/1
andrew-ma 2 years ago
parent bb73e516cb
commit 2e6dc03f34
  1. 18
      pySim/commands.py

@ -170,11 +170,23 @@ class SimCardCommands(object):
return None, sw
self.select_path(ef)
pdu = self.cla_byte + 'd6%04x%02x' % (offset, data_length) + data
res = self._tp.send_apdu_checksw(pdu)
total_data = ''
total_sw = "9000"
chunk_offset = offset
while chunk_offset < data_length:
chunk_len = min(255, data_length - chunk_offset)
# chunk_offset is bytes, but data slicing is hex chars, so we need to multiply by 2
pdu = self.cla_byte + 'd6%04x%02x' % (chunk_offset, chunk_len) + data[chunk_offset*2 : (chunk_offset+chunk_len)*2]
chunk_data, chunk_sw = self._tp.send_apdu(pdu)
if chunk_sw == total_sw:
total_data += chunk_data
chunk_offset += chunk_len
else:
total_sw = chunk_sw
raise ValueError('Failed to write chunk (chunk_offset %d, chunk_len %d)' % (chunk_offset, chunk_len))
if verify:
self.verify_binary(ef, data, offset)
return res
return total_data, total_sw
def verify_binary(self, ef, data:str, offset:int=0):
"""Verify contents of transparent EF.

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