Change in pysim[master]: Allow update_binary function to write more than 255 bytes

andrew-ma gerrit-no-reply at lists.osmocom.org
Sun Aug 1 05:29:51 UTC 2021


andrew-ma has uploaded this change for review. ( https://gerrit.osmocom.org/c/pysim/+/25114 )


Change subject: Allow update_binary function to write more than 255 bytes
......................................................................

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
---
M pySim/commands.py
1 file changed, 15 insertions(+), 3 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/pysim refs/changes/14/25114/1

diff --git a/pySim/commands.py b/pySim/commands.py
index 76b7cd5..9657162 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -170,11 +170,23 @@
 				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.

-- 
To view, visit https://gerrit.osmocom.org/c/pysim/+/25114
To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings

Gerrit-Project: pysim
Gerrit-Branch: master
Gerrit-Change-Id: Icc240d5c8c04198640eb118565ea99f10ba27466
Gerrit-Change-Number: 25114
Gerrit-PatchSet: 1
Gerrit-Owner: andrew-ma <andrewm098 at gmail.com>
Gerrit-MessageType: newchange
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osmocom.org/pipermail/gerrit-log/attachments/20210801/d16f1965/attachment.htm>


More information about the gerrit-log mailing list