commands.py: Add support for multiple logical channels.
Historically we always only had one instance of SimCardCommands, but
with this patch we can now have multiple instances, one for each lchan.
The SimCardCommands class is aware of the logical channel it runs on
and will patch the CLA byte accordingly.
Change-Id: Ibe5650dedc0f7681acf82018a86f83377ba81d30
Related: OS#6230
diff --git a/pySim/commands.py b/pySim/commands.py
index e072069..3edee98 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -26,7 +26,7 @@
from construct import *
from pySim.construct import LV
-from pySim.utils import rpad, lpad, b2h, h2b, sw_match, bertlv_encode_len, Hexstr, h2i, str_sanitize, expand_hex
+from pySim.utils import rpad, lpad, b2h, h2b, sw_match, bertlv_encode_len, Hexstr, h2i, i2h, str_sanitize, expand_hex
from pySim.utils import Hexstr, SwHexstr, ResTuple
from pySim.exceptions import SwMatchError
from pySim.transport import LinkBase
@@ -34,11 +34,70 @@
# A path can be either just a FID or a list of FID
Path = typing.Union[Hexstr, List[Hexstr]]
+def lchan_nr_to_cla(cla: int, lchan_nr: int) -> int:
+ """Embed a logical channel number into the CLA byte."""
+ # TS 102 221 10.1.1 Coding of Class Byte
+ if lchan_nr < 4:
+ # standard logical channel number
+ if cla >> 4 in [0x0, 0xA, 0x8]:
+ return (cla & 0xFC) | (lchan_nr & 3)
+ else:
+ raise ValueError('Undefined how to use CLA %2X with logical channel %u' % (cla, lchan_nr))
+ elif lchan_nr < 16:
+ # extended logical channel number
+ if cla >> 6 in [1, 3]:
+ return (cla & 0xF0) | ((lchan_nr - 4) & 0x0F)
+ else:
+ raise ValueError('Undefined how to use CLA %2X with logical channel %u' % (cla, lchan_nr))
+ else:
+ raise ValueError('logical channel outside of range 0 .. 15')
+
+def cla_with_lchan(cla_byte: Hexstr, lchan_nr: int) -> Hexstr:
+ """Embed a logical channel number into the hex-string encoded CLA value."""
+ cla_int = h2i(cla_byte)[0]
+ return i2h([lchan_nr_to_cla(cla_int, lchan_nr)])
+
class SimCardCommands:
- def __init__(self, transport: LinkBase):
+ """Class providing methods for various card-specific commands such as SELECT, READ BINARY, etc.
+ Historically one instance exists below CardBase, but with the introduction of multiple logical
+ channels there can be multiple instances. The lchan number will then be patched into the CLA
+ byte by the respective instance. """
+ def __init__(self, transport: LinkBase, lchan_nr: int = 0):
self._tp = transport
- self.cla_byte = "a0"
+ self._cla_byte = None
self.sel_ctrl = "0000"
+ self.lchan_nr = lchan_nr
+ # invokes the setter below
+ self.cla_byte = "a0"
+
+ def fork_lchan(self, lchan_nr: int) -> 'SimCardCommands':
+ """Fork a per-lchan specific SimCardCommands instance off the current instance."""
+ ret = SimCardCommands(transport = self._tp, lchan_nr = lchan_nr)
+ ret.cla_byte = self._cla_byte
+ return ret
+
+ @property
+ def cla_byte(self) -> Hexstr:
+ """Return the (cached) patched default CLA byte for this card."""
+ return self._cla4lchan
+
+ @cla_byte.setter
+ def cla_byte(self, new_val: Hexstr):
+ """Set the (raw, without lchan) default CLA value for this card."""
+ self._cla_byte = new_val
+ # compute cached result
+ self._cla4lchan = cla_with_lchan(self._cla_byte, self.lchan_nr)
+
+ def cla4lchan(self, cla: Hexstr) -> Hexstr:
+ """Compute the lchan-patched value of the given CLA value. If no CLA
+ value is provided as argument, the lchan-patched version of the SimCardCommands._cla_byte
+ value is used. Most commands will use the latter, while some wish to override it and
+ can pass it as argument here."""
+ if not cla:
+ # return cached result to avoid re-computing this over and over again
+ return self._cla4lchan
+ else:
+ return cla_with_lchan(cla, self.lchan_nr)
# Extract a single FCP item from TLV
def __parse_fcp(self, fcp: Hexstr):
@@ -344,9 +403,9 @@
# TS 102 221 Section 11.3.1 low-level helper
def _retrieve_data(self, tag: int, first: bool = True) -> ResTuple:
if first:
- pdu = '80cb008001%02x' % (tag)
+ pdu = self.cla4lchan('80') + 'cb008001%02x' % (tag)
else:
- pdu = '80cb000000'
+ pdu = self.cla4lchan('80') + 'cb000000'
return self._tp.send_apdu_checksw(pdu)
def retrieve_data(self, ef: Path, tag: int) -> ResTuple:
@@ -376,7 +435,7 @@
p1 = 0x00
if isinstance(data, bytes) or isinstance(data, bytearray):
data = b2h(data)
- pdu = '80db00%02x%02x%s' % (p1, len(data)//2, data)
+ pdu = self.cla4lchan('80') + 'db00%02x%02x%s' % (p1, len(data)//2, data)
return self._tp.send_apdu_checksw(pdu)
def set_data(self, ef, tag: int, value: str, verify: bool = False, conserve: bool = False) -> ResTuple:
@@ -419,7 +478,7 @@
if len(rand) != 32:
raise ValueError('Invalid rand')
self.select_path(['3f00', '7f20'])
- return self._tp.send_apdu_checksw('a0' + '88000010' + rand, sw='9000')
+ return self._tp.send_apdu_checksw(self.cla4lchan('a0') + '88000010' + rand, sw='9000')
def authenticate(self, rand: Hexstr, autn: Hexstr, context: str = '3g') -> ResTuple:
"""Execute AUTHENTICATE (USIM/ISIM).
@@ -451,7 +510,7 @@
def status(self) -> ResTuple:
"""Execute a STATUS command as per TS 102 221 Section 11.1.2."""
- return self._tp.send_apdu_checksw('80F20000ff')
+ return self._tp.send_apdu_checksw(self.cla4lchan('80') + 'F20000ff')
def deactivate_file(self) -> ResTuple:
"""Execute DECATIVATE FILE command as per TS 102 221 Section 11.1.14."""
@@ -471,7 +530,7 @@
def resize_file(self, payload: Hexstr) -> ResTuple:
"""Execute RESIZE FILE command as per TS 102 222 Section 6.10"""
- return self._tp.send_apdu_checksw('80d40000%02x%s' % (len(payload)//2, payload))
+ return self._tp.send_apdu_checksw(self.cla4lchan('80') + 'd40000%02x%s' % (len(payload)//2, payload))
def delete_file(self, fid: Hexstr) -> ResTuple:
"""Execute DELETE FILE command as per TS 102 222 Section 6.4"""