From 01e05ed5ae67942655cdca7e244f758302e66c1d Mon Sep 17 00:00:00 2001
From: Arnaud Fontaine <arnaud.fontaine@ssi.gouv.fr>
Date: Fri, 15 May 2020 10:36:47 +0200
Subject: [PATCH] smartpgp-cli: add getm-sm-key command

---
 bin/smartpgp-cli          |  1 +
 bin/smartpgp/commands.py  |  6 ++++++
 bin/smartpgp/highlevel.py | 42 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/bin/smartpgp-cli b/bin/smartpgp-cli
index dec8254..5a2b7de 100755
--- a/bin/smartpgp-cli
+++ b/bin/smartpgp-cli
@@ -38,6 +38,7 @@ VALID_COMMANDS={
         'switch-p384': CardConnectionContext.cmd_switch_p384,
         'switch-p521': CardConnectionContext.cmd_switch_p521,
         'generate-sm-key': CardConnectionContext.cmd_generate_sm_key,
+        'get-sm-key': CardConnectionContext.cmd_get_sm_key,
         'set-resetting-code': CardConnectionContext.cmd_set_resetting_code,
         'unblock-pin': CardConnectionContext.cmd_unblock_pin,
         'put-sm-key': CardConnectionContext.cmd_put_sm_key,
diff --git a/bin/smartpgp/commands.py b/bin/smartpgp/commands.py
index bd98745..7b78e02 100644
--- a/bin/smartpgp/commands.py
+++ b/bin/smartpgp/commands.py
@@ -40,6 +40,7 @@ ACTIVATE = [0x00, 0x44, 0x00, 0x00]
 ACTIVATE_FULL = [0x00, 0x44, 0x00, 0x01]
 GET_SM_CURVE_OID = [0x00, 0xca, 0x00, 0xd4]
 GENERATE_ASYMETRIC_KEYPAIR = [0x00, 0x47, 0x80, 0x00]
+GET_ASYMETRIC_KEYPAIR = [0x00, 0x47, 0x81, 0x00]
 
 ALGS_ALIASES = {
     'ansix9p256r1': 'ansix9p256r1',
@@ -232,6 +233,11 @@ def generate_sm_key(connection):
     apdu = apdu + [0x00]
     return _raw_send_apdu(connection,"Generate SM key",apdu)
 
+def get_sm_key(connection):
+    apdu = assemble_with_len(GET_ASYMETRIC_KEYPAIR, [0xA6, 0x00])
+    apdu = apdu + [0x00]
+    return _raw_send_apdu(connection,"Get SM key",apdu)
+
 def set_resetting_code(connection, resetting_code): 
     apdu = assemble_with_len([0x00, 0xDA, 0x00, 0xD3], ascii_encode_pin(resetting_code))
     _raw_send_apdu(connection,"Define the resetting code (PUK)",apdu)
diff --git a/bin/smartpgp/highlevel.py b/bin/smartpgp/highlevel.py
index a1f9309..a06fda4 100644
--- a/bin/smartpgp/highlevel.py
+++ b/bin/smartpgp/highlevel.py
@@ -189,6 +189,48 @@ class CardConnectionContext:
             f.write(pubkey_der)
             f.close()
 
+    def cmd_get_sm_key(self):
+        if not self.output:
+            print "Missing output file name"
+            return
+        self.connect()
+        (data,sw1,sw2) = get_sm_key(self.connection)
+        if sw1!=0x90 or sw2!=0x00:
+            print "get_sm_key failed"
+            return
+        if len(data) < 4 or data[0]!=0x7f or data[1]!=0x49:
+            print "Strange reply for get_sm_key"
+            return
+        blob_len = data[2]
+        blob = data[3:]
+        assert(blob_len == len(blob))
+        if blob[0]!=0x86:
+            print "get_sm_key something not a public key"
+            return
+        assert(blob[1]==len(blob[2:]))
+        pubkey = blob[2:]
+        # get curve OID
+        curve_oid_der = get_sm_curve_oid(self.connection)
+        if not curve_oid_der:
+            print "Error getting SM curve OID"
+            return
+        (curve_oid,_) = der_decoder.decode(str(curve_oid_der))
+        # now format it to DER [RFC5480]
+        s = univ.Sequence()
+        oid_elliptic_curve_pubkey = univ.ObjectIdentifier('1.2.840.10045.2.1')
+        s.setComponentByPosition(0,oid_elliptic_curve_pubkey)
+        s.setComponentByPosition(1,curve_oid)
+        bs = univ.BitString("'%s'H" % binascii.hexlify(bytearray(pubkey)))
+        s2 = univ.Sequence()
+        s2.setComponentByPosition(0,s)
+        s2.setComponentByPosition(1,bs)
+        pubkey_der = der_encoder.encode(s2)
+        print binascii.hexlify(pubkey_der)
+        # and write result
+        with open(self.output,"wb") as f:
+            f.write(pubkey_der)
+            f.close()
+
     def cmd_put_sm_key(self):
         if self.input is None:
             print "No input key file"