From 2e6dc03f345150353ecc796f18614c02256bd2df Mon Sep 17 00:00:00 2001 From: andrew-ma Date: Sat, 31 Jul 2021 22:18:24 -0700 Subject: [PATCH] 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 --- pySim/commands.py | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/pySim/commands.py b/pySim/commands.py index 76b7cd58..96571625 100644 --- a/pySim/commands.py +++ b/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.