nPA: fixed resume PIN command

PACE with CAN followed by PACE with PIN in SM failed, because the
eac_ctx holding the SM context was always cleared at the beginning of
the second PACE run.

virtualsmartcard/src/vpicc/virtualsmartcard/cards/nPA.py

@@ -172,9 +172,6 @@ class nPA_SE(Security_Environment):
         if  tlv_data != []:
             raise SwError(SW["WARN_NOINFO63"])
 
-        self.__eac_abort()
-
-        self.eac_ctx = pace.EAC_CTX_new()
         if self.at.keyref_is_mrz():
             self.sec = pace.PACE_SEC_new(self.sam.mrz, pace.PACE_MRZ)
         elif self.at.keyref_is_can():
@@ -198,9 +195,13 @@ class nPA_SE(Security_Environment):
         else:
             raise SwError(SW["ERR_INCORRECTPARAMETERS"])
 
+        if not self.eac_ctx:
+            self.eac_ctx = pace.EAC_CTX_new()
+
             ef_card_access = self.mf.select('fid', 0x011c)
             ef_card_access_data = ef_card_access.data
             pace.EAC_CTX_init_ef_cardaccess(ef_card_access_data, self.eac_ctx)
+
             ef_card_security = self.mf.select('fid', 0x011d)
             ef_card_security_data = ef_card_security.data
             ca_pubkey = pace.CA_get_pubkey(self.eac_ctx, ef_card_security_data)