/src/opensc/src/libopensc/apdu.c

Source
/*
 * apdu.c: basic APDU handling functions
 *
 * Copyright (C) 2005 Nils Larsch <nils@larsch.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "internal.h"
#include "asn1.h"

/*********************************************************************/
/*   low level APDU handling functions                               */
/*********************************************************************/

/** Calculates the length of the encoded APDU in octets.
 *  @param  apdu   the APDU
 *  @param  proto  the desired protocol
 *  @return length of the encoded APDU
 */
size_t sc_apdu_get_length(const sc_apdu_t *apdu, unsigned int proto)
{
  size_t ret = 4;

  switch (apdu->cse) {
  case SC_APDU_CASE_1:
    if (proto == SC_PROTO_T0)
      ret++;
    break;
  case SC_APDU_CASE_2_SHORT:
    ret++;
    break;
  case SC_APDU_CASE_2_EXT:
    ret += (proto == SC_PROTO_T0 ? 1 : 3);
    break;
  case SC_APDU_CASE_3_SHORT:
    ret += 1 + apdu->lc;
    break;
  case SC_APDU_CASE_3_EXT:
    ret += apdu->lc + (proto == SC_PROTO_T0 ? 1 : 3);
    break;
  case SC_APDU_CASE_4_SHORT:
    ret += apdu->lc + (proto != SC_PROTO_T0 ? 2 : 1);
    break;
  case SC_APDU_CASE_4_EXT:
    ret += apdu->lc + (proto == SC_PROTO_T0 ? 1 : 5);
    break;
  default:
    return 0;
  }
  return ret;
}

/** Encodes a APDU as an octet string
 *  @param  ctx     sc_context_t object (used for logging)
 *  @param  apdu    APDU to be encoded as an octet string
 *  @param  proto   protocol version to be used
 *  @param  out     output buffer of size outlen.
 *  @param  outlen  size of the output buffer
 *  @return SC_SUCCESS on success and an error code otherwise
 */
int sc_apdu2bytes(sc_context_t *ctx, const sc_apdu_t *apdu,
  unsigned int proto, u8 *out, size_t outlen)
{
  u8     *p = out;

  size_t len = sc_apdu_get_length(apdu, proto);

  if (out == NULL || outlen < len)
    return SC_ERROR_INVALID_ARGUMENTS;
  /* CLA, INS, P1 and P2 */
  *p++ = apdu->cla;
  *p++ = apdu->ins;
  *p++ = apdu->p1;
  *p++ = apdu->p2;
  /* case depend part */
  switch (apdu->cse) {
  case SC_APDU_CASE_1:
    /* T0 needs an additional 0x00 byte */
    if (proto == SC_PROTO_T0)
      *p = (u8)0x00;
    break;
  case SC_APDU_CASE_2_SHORT:
    *p = (u8)apdu->le;
    break;
  case SC_APDU_CASE_2_EXT:
    if (proto == SC_PROTO_T0)
      /* T0 extended APDUs look just like short APDUs */
      *p = (u8)apdu->le;
    else {
      /* in case of T1 always use 3 bytes for length */
      *p++ = (u8)0x00;
      *p++ = (u8)(apdu->le >> 8);
      *p = (u8)apdu->le;
    }
    break;
  case SC_APDU_CASE_3_SHORT:
    *p++ = (u8)apdu->lc;
    memcpy(p, apdu->data, apdu->lc);
    break;
  case SC_APDU_CASE_3_EXT:
    if (proto == SC_PROTO_T0) {
      /* in case of T0 the command is transmitted in chunks
       * < 255 using the ENVELOPE command ... */
      if (apdu->lc > 255) {
        /* ... so if Lc is greater than 255 bytes
         * an error has occurred on a higher level */
        sc_log(ctx, "invalid Lc length for CASE 3 extended APDU (need ENVELOPE)");
        return SC_ERROR_INVALID_ARGUMENTS;
      }
    }
    else {
      /* in case of T1 always use 3 bytes for length */
      *p++ = (u8)0x00;
      *p++ = (u8)(apdu->lc >> 8);
      *p++ = (u8)apdu->lc;
    }
    memcpy(p, apdu->data, apdu->lc);
    break;
  case SC_APDU_CASE_4_SHORT:
    *p++ = (u8)apdu->lc;
    memcpy(p, apdu->data, apdu->lc);
    p += apdu->lc;
    /* in case of T0 no Le byte is added */
    if (proto != SC_PROTO_T0)
      *p = (u8)apdu->le;
    break;
  case SC_APDU_CASE_4_EXT:
    if (proto == SC_PROTO_T0) {
      /* again a T0 extended case 4 APDU looks just
       * like a short APDU, the additional data is
       * transferred using ENVELOPE and GET RESPONSE */
      *p++ = (u8)apdu->lc;
      memcpy(p, apdu->data, apdu->lc);
    }
    else {
      *p++ = (u8)0x00;
      *p++ = (u8)(apdu->lc >> 8);
      *p++ = (u8)apdu->lc;
      memcpy(p, apdu->data, apdu->lc);
      p += apdu->lc;
      /* only 2 bytes are use to specify the length of the
       * expected data */
      *p++ = (u8)(apdu->le >> 8);
      *p = (u8)apdu->le;
    }
    break;
  }

  return SC_SUCCESS;
}

int sc_apdu_get_octets(sc_context_t *ctx, const sc_apdu_t *apdu, u8 **buf,
  size_t *len, unsigned int proto)
{
  size_t  nlen;
  u8  *nbuf;

  if (apdu == NULL || buf == NULL || len == NULL)
    return SC_ERROR_INVALID_ARGUMENTS;

  /* get the estimated length of encoded APDU */
  nlen = sc_apdu_get_length(apdu, proto);
  if (nlen == 0)
    return SC_ERROR_INTERNAL;
  nbuf = malloc(nlen);
  if (nbuf == NULL)
    return SC_ERROR_OUT_OF_MEMORY;
  /* encode the APDU in the buffer */
  if (sc_apdu2bytes(ctx, apdu, proto, nbuf, nlen) != SC_SUCCESS) {
    free(nbuf);
    return SC_ERROR_INTERNAL;
  }
  *buf = nbuf;
  *len = nlen;

  return SC_SUCCESS;
}

int sc_apdu_set_resp(sc_context_t *ctx, sc_apdu_t *apdu, const u8 *buf,
  size_t len)
{
  if (len < 2) {
    /* no SW1 SW2 ... something went terrible wrong */
    sc_log(ctx, "invalid response: SW1 SW2 missing");
    return SC_ERROR_INTERNAL;
  }
  /* set the SW1 and SW2 status bytes (the last two bytes of
   * the response */
  apdu->sw1 = (unsigned int)buf[len - 2];
  apdu->sw2 = (unsigned int)buf[len - 1];
  len -= 2;
  /* set output length and copy the returned data if necessary */
  if (len <= apdu->resplen)
    apdu->resplen = len;

  if (apdu->resplen != 0)
    memcpy(apdu->resp, buf, apdu->resplen);

  return SC_SUCCESS;
}


/*********************************************************************/
/*   higher level APDU transfer handling functions                   */
/*********************************************************************/
/*   +------------------+
 *   | sc_transmit_apdu |
 *   +------------------+
 *         |  |  |
 *         |  |  |     detect APDU cse               +--------------------+
 *         |  |  +---------------------------------> | sc_detect_apdu_cse |
 *         |  |                                      +--------------------+
 *         |  |        check consistency of APDU     +--------------------+
 *         |  +------------------------------------> | sc_check_apdu      |
 *         |                                         +--------------------+
 *         |           send single APDU              +--------------------+
 *         +---------------------------------------> | sc_transmit        |
 *                        ^                          +--------------------+
 *                        |                               |
 *                        |  re-transmit if wrong length  |
 *                        |       or GET RESPONSE         |
 *                        +-------------------------------+
 *                                                        |
 *                                                        v
 *                                               card->reader->ops->transmit
 */

/** basic consistency check of the sc_apdu_t object
 *  @param  ctx   sc_context_t object for error messages
 *  @param  apdu  sc_apdu_t object to check
 *  @return SC_SUCCESS on success and an error code otherwise
 */
int
sc_check_apdu(sc_card_t *card, const sc_apdu_t *apdu)
{
  if ((apdu->cse & ~SC_APDU_SHORT_MASK) == 0) {
    /* length check for short APDU */
    if (apdu->le > 256 || (apdu->lc > 255 && (apdu->flags & SC_APDU_FLAGS_CHAINING) == 0))   {
      sc_log(card->ctx, "failed length check for short APDU");
      goto error;
    }
  }
  else if ((apdu->cse & SC_APDU_EXT) != 0) {
    /* check if the card supports extended APDUs */
    if ((card->caps & SC_CARD_CAP_APDU_EXT) == 0) {
      sc_log(card->ctx, "card doesn't support extended APDUs");
      goto error;
    }
    /* length check for extended APDU */
    if (apdu->le > 65536 || apdu->lc > 65535)   {
      sc_log(card->ctx, "failed length check for extended APDU");
      goto error;
    }
  }
  else   {
    goto error;
  }

  switch (apdu->cse & SC_APDU_SHORT_MASK) {
  case SC_APDU_CASE_1:
    /* no data is sent or received */
    if (apdu->datalen != 0 || apdu->lc != 0 || apdu->le != 0)
      goto error;
    break;
  case SC_APDU_CASE_2_SHORT:
    /* no data is sent */
    if (apdu->datalen != 0 || apdu->lc != 0)
      goto error;
    /* data is expected       */
    if (apdu->resplen == 0 || apdu->resp == NULL)
      goto error;
    break;
  case SC_APDU_CASE_3_SHORT:
    /* data is sent */
    if (apdu->datalen == 0 || apdu->data == NULL || apdu->lc == 0)
      goto error;
    /* no data is expected    */
    if (apdu->le != 0)
      goto error;
    /* inconsistent datalen   */
    if (apdu->datalen != apdu->lc)
      goto error;
    break;
  case SC_APDU_CASE_4_SHORT:
    /* data is sent */
    if (apdu->datalen == 0 || apdu->data == NULL || apdu->lc == 0)
      goto error;
    /* data is expected       */
    if (apdu->resplen == 0 || apdu->resp == NULL)
      goto error;
    /* inconsistent datalen   */
    if (apdu->datalen != apdu->lc)
      goto error;
    break;
  default:
    sc_log(card->ctx, "Invalid APDU case %d", apdu->cse);
    return SC_ERROR_INVALID_ARGUMENTS;
  }
  return SC_SUCCESS;
error:
  sc_log(card->ctx, "Invalid Case %d %s APDU:\n"
    "cse=%02x cla=%02x ins=%02x p1=%02x p2=%02x lc=%lu le=%lu\n"
    "resp=%p resplen=%lu data=%p datalen=%lu flags=0x%8.8lx",
    apdu->cse & SC_APDU_SHORT_MASK,
    (apdu->cse & SC_APDU_EXT) != 0 ? "extended" : "short",
    apdu->cse, apdu->cla, apdu->ins, apdu->p1, apdu->p2,
    (unsigned long) apdu->lc, (unsigned long) apdu->le,
    apdu->resp, (unsigned long) apdu->resplen,
    apdu->data, (unsigned long) apdu->datalen, apdu->flags);
  return SC_ERROR_INVALID_ARGUMENTS;
}

/** Tries to determine the APDU type (short or extended) of the supplied
 *  APDU if one of the SC_APDU_CASE_? types is used.
 *  @param  apdu  APDU object
 */
static void
sc_detect_apdu_cse(const sc_card_t *card, sc_apdu_t *apdu)
{
  if (apdu->cse == SC_APDU_CASE_2 || apdu->cse == SC_APDU_CASE_3 ||
      apdu->cse == SC_APDU_CASE_4) {
    int btype = apdu->cse & SC_APDU_SHORT_MASK;
    /* if either Lc or Le is bigger than the maximum for
     * short APDUs and the card supports extended APDUs
     * use extended APDUs (unless Lc is greater than
     * 255 and command chaining is activated) */
    if ((apdu->le > 256 || (apdu->lc > 255 && (apdu->flags & SC_APDU_FLAGS_CHAINING) == 0)) &&
        (card->caps & SC_CARD_CAP_APDU_EXT) != 0)
      btype |= SC_APDU_EXT;
    apdu->cse = btype;
  }
}


static int
sc_single_transmit(struct sc_card *card, struct sc_apdu *apdu)
{
  struct sc_context *ctx  = card->ctx;
  int rv;

  LOG_FUNC_CALLED(ctx);
  if (card->reader->ops->transmit == NULL)
    LOG_TEST_RET(card->ctx, SC_ERROR_NOT_SUPPORTED, "cannot transmit APDU");

  sc_log(ctx, "CLA:%X, INS:%X, P1:%X, P2:%X, data(%zu) %p",
      apdu->cla, apdu->ins, apdu->p1, apdu->p2, apdu->datalen, apdu->data);
#ifdef ENABLE_SM
  if (card->sm_ctx.sm_mode == SM_MODE_TRANSMIT
        && (apdu->flags & SC_APDU_FLAGS_NO_SM) == 0) {
    LOG_FUNC_RETURN(ctx, sc_sm_single_transmit(card, apdu));
  }
#endif

  /* send APDU to the reader driver */
  rv = card->reader->ops->transmit(card->reader, apdu);
  LOG_TEST_RET(ctx, rv, "unable to transmit APDU");

  LOG_FUNC_RETURN(ctx, rv);
}


static int
sc_set_le_and_transmit(struct sc_card *card, struct sc_apdu *apdu, size_t olen)
{
  struct sc_context *ctx  = card->ctx;
  size_t nlen = apdu->sw2 ? (size_t)apdu->sw2 : 256;
  int rv;

  LOG_FUNC_CALLED(ctx);
  /* we cannot re-transmit the APDU with the demanded Le value
   * as the buffer is too small => error */
  if (olen < nlen)
    LOG_TEST_RET(ctx, SC_ERROR_WRONG_LENGTH, "wrong length: required length exceeds resplen");

  /* don't try again if it doesn't work this time */
  apdu->flags  |= SC_APDU_FLAGS_NO_RETRY_WL;
  /* set the new expected length */
  apdu->resplen = olen;
  apdu->le      = nlen;
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  /* Belpic V1 applets have a problem: if the card sends a 6C XX (only XX bytes available),
   * and we resend the command too soon (i.e. the reader is too fast), the card doesn't respond.
   * So we build in a delay. */
  if (card->type == SC_CARD_TYPE_BELPIC_EID)
    msleep(40);
#endif

  /* re-transmit the APDU with new Le length */
  rv = sc_single_transmit(card, apdu);
  LOG_TEST_RET(ctx, rv, "cannot re-transmit APDU");

  LOG_FUNC_RETURN(ctx, rv);
}


static int
sc_get_response(struct sc_card *card, struct sc_apdu *apdu, size_t olen)
{
  struct sc_context *ctx  = card->ctx;
  size_t le, minlen, buflen;
  unsigned char *buf;
  int rv;

  LOG_FUNC_CALLED(ctx);
  if (apdu->le == 0) {
    /* no data is requested => change return value to 0x9000 and ignore the remaining data */
    apdu->sw1 = 0x90;
    apdu->sw2 = 0x00;
    return SC_SUCCESS;
  }

  /* this should _never_ happen */
  if (!card->ops->get_response)
    LOG_TEST_RET(ctx, SC_ERROR_NOT_SUPPORTED, "no GET RESPONSE command");

  /* call GET RESPONSE until we have read all data requested or until the card returns 0x9000,
   * whatever happens first. */

  /* if there are already data in response append a new data to the end of the buffer */
  buf = apdu->resp + apdu->resplen;

  /* read as much data as fits in apdu->resp (i.e. min(apdu->resplen, amount of data available)). */
  buflen = olen - apdu->resplen;

  /* 0x6100 means at least 256 more bytes to read */
  le = apdu->sw2 != 0 ? (size_t)apdu->sw2 : 256;
  /* we try to read at least as much as bytes as promised in the response bytes */
  minlen = le;

  do {
    unsigned char resp[256];
    size_t resp_len = le;

    /* we have all the data the caller requested even if the card has more data */
    if (buflen == 0)
      break;

    /* call GET RESPONSE to get more date from the card;
     * note: GET RESPONSE returns the left amount of data (== SW2) */
    memset(resp, 0, sizeof(resp));
    rv = card->ops->get_response(card, &resp_len, resp);
    if (rv < 0)   {
#ifdef ENABLE_SM
      if (resp_len)   {
        sc_log_hex(ctx, "SM response data", resp, resp_len);
        sc_sm_update_apdu_response(card, resp, resp_len, rv, apdu);
      }
#endif
      LOG_TEST_RET(ctx, rv, "GET RESPONSE error");
    }

    le = resp_len;
    /* copy as much as will fit in requested buffer */
    if (buflen < le)
      le = buflen;

    memcpy(buf, resp, le);
    buf    += le;
    buflen -= le;

    minlen -= le;
    if (rv != 0)
      le = minlen = (size_t)rv;
    else
      /* if the card has returned 0x9000 but we still expect data ask for more
       * until we have read enough bytes */
      le = minlen;
  } while (rv != 0 && minlen != 0);

  /* we've read all data, let's return 0x9000 */
  apdu->resplen = buf - apdu->resp;
  apdu->sw1 = 0x90;
  apdu->sw2 = 0x00;

  LOG_FUNC_RETURN(ctx, SC_SUCCESS);
}


/** Sends a single APDU to the card reader and calls GET RESPONSE to get the return data if necessary.
 *  @param  card  sc_card_t object for the smartcard
 *  @param  apdu  APDU to be sent
 *  @return SC_SUCCESS on success and an error value otherwise
 */
static int
sc_transmit(sc_card_t *card, sc_apdu_t *apdu)
{
  struct sc_context *ctx  = card->ctx;
  size_t       olen  = apdu->resplen;
  int          r;

  LOG_FUNC_CALLED(ctx);

  r = sc_single_transmit(card, apdu);
  LOG_TEST_RET(ctx, r, "transmit APDU failed");

  /* ok, the APDU was successfully transmitted. Now we have two special cases:
   * 1. the card returned 0x6Cxx: in this case APDU will be re-transmitted with Le set to SW2
   * (possible only if response buffer size is larger than new Le = SW2)
   */
  if (apdu->sw1 == 0x6C && (apdu->flags & SC_APDU_FLAGS_NO_RETRY_WL) == 0) {
    r = sc_set_le_and_transmit(card, apdu, olen);
    LOG_TEST_RET(ctx, r, "cannot re-transmit APDU ");
  }

  /* 2. the card returned 0x61xx: more data can be read from the card
   *    using the GET RESPONSE command (mostly used in the T0 protocol).
   *    Unless the SC_APDU_FLAGS_NO_GET_RESP is set we try to read as
   *    much data as possible using GET RESPONSE.
   */
  if (apdu->sw1 == 0x61 && (apdu->flags & SC_APDU_FLAGS_NO_GET_RESP) == 0) {
    r = sc_get_response(card, apdu, olen);
    LOG_TEST_RET(ctx, r, "cannot get all data with 'GET RESPONSE'");
  }

  LOG_FUNC_RETURN(ctx, SC_SUCCESS);
}


int sc_transmit_apdu(sc_card_t *card, sc_apdu_t *apdu)
{
  int r = SC_SUCCESS;

  if (card == NULL || apdu == NULL)
    return SC_ERROR_INVALID_ARGUMENTS;

  LOG_FUNC_CALLED(card->ctx);

  /* determine the APDU type if necessary, i.e. to use
   * short or extended APDUs  */
  sc_detect_apdu_cse(card, apdu);
  /* basic APDU consistency check */
  r = sc_check_apdu(card, apdu);
  if (r != SC_SUCCESS)
    return SC_ERROR_INVALID_ARGUMENTS;

  r = sc_lock(card);  /* acquire card lock*/
  if (r != SC_SUCCESS) {
    sc_log(card->ctx, "unable to acquire lock");
    return r;
  }

#if ENABLE_SM
  if (card->sm_ctx.sm_mode == SM_MODE_TRANSMIT
      && (apdu->flags & SC_APDU_FLAGS_CHAINING) != 0
      && (apdu->flags & SC_APDU_FLAGS_SM_CHAINING) != 0) {
    sc_log(card->ctx,"Let SM do the chaining");
    r = sc_transmit(card, apdu);
  } else
#endif
  if ((apdu->flags & SC_APDU_FLAGS_CHAINING) != 0) {
    /* divide et impera: transmit APDU in chunks with Lc <= max_send_size
     * bytes using command chaining */
    size_t    len  = apdu->datalen;
    const u8  *buf = apdu->data;
    size_t    max_send_size = sc_get_max_send_size(card);

    while (len != 0) {
      size_t    plen;
      sc_apdu_t tapdu;
      int       last = 0;

      tapdu = *apdu;
      /* clear chaining flag */
      tapdu.flags &= ~SC_APDU_FLAGS_CHAINING;
      if (len > max_send_size) {
        /* adjust APDU case: in case of CASE 4 APDU
         * the intermediate APDU are of CASE 3 */
        if ((tapdu.cse & SC_APDU_SHORT_MASK) == SC_APDU_CASE_4_SHORT)
          tapdu.cse--;
        /* XXX: the chunk size must be adjusted when
         *      secure messaging is used */
        plen          = max_send_size;
        tapdu.cla    |= 0x10;
        /* the intermediate APDU don't expect response data */
        tapdu.le      = 0;
        tapdu.resplen = 0;
        tapdu.resp    = NULL;
      } else {
        plen = len;
        last = 1;
      }
      tapdu.data    = buf;
      tapdu.datalen = tapdu.lc = plen;

      r = sc_check_apdu(card, &tapdu);
      if (r != SC_SUCCESS) {
        sc_log(card->ctx, "inconsistent APDU while chaining");
        break;
      }

      r = sc_transmit(card, &tapdu);
      if (r != SC_SUCCESS)
        break;
      if (last != 0) {
        /* in case of the last APDU set the SW1
         * and SW2 bytes in the original APDU */
        apdu->sw1 = tapdu.sw1;
        apdu->sw2 = tapdu.sw2;
        apdu->resplen = tapdu.resplen;
      } else {
        /* otherwise check the status bytes */
        r = sc_check_sw(card, tapdu.sw1, tapdu.sw2);
        if (r != SC_SUCCESS)
          break;
      }
      len -= plen;
      buf += plen;
    }
  } else {
    /* transmit single APDU */
    r = sc_transmit(card, apdu);
  }

  if (r == SC_ERROR_CARD_RESET || r == SC_ERROR_READER_REATTACHED) {
    /* give card driver a chance to react on resets */
    if (card->ops->card_reader_lock_obtained)
      card->ops->card_reader_lock_obtained(card, 1);
  }

  /* all done => release lock */
  if (sc_unlock(card) != SC_SUCCESS)
    sc_log(card->ctx, "sc_unlock failed");

  return r;
}


int
sc_bytes2apdu(sc_context_t *ctx, const u8 *buf, size_t len, sc_apdu_t *apdu)
{
  const unsigned char *p;
  size_t len0;

  if (!buf || !apdu)
    return SC_ERROR_INVALID_ARGUMENTS;

  len0 = len;
  if (len < 4) {
    sc_log(ctx, "APDU too short (must be at least 4 bytes)");
    return SC_ERROR_INVALID_DATA;
  }

  memset(apdu, 0, sizeof *apdu);
  p = buf;
  apdu->cla = *p++;
  apdu->ins = *p++;
  apdu->p1 = *p++;
  apdu->p2 = *p++;
  len -= 4;

  if (!len) {
    apdu->cse = SC_APDU_CASE_1;
    sc_log(ctx, "CASE_1 APDU: %zu bytes:\tins=%02x p1=%02x p2=%02x lc=%04zx le=%04zx",
        len0, apdu->ins, apdu->p1, apdu->p2, apdu->lc, apdu->le);
    return SC_SUCCESS;
  }

  if (*p == 0 && len >= 3) {
    /* ...must be an extended APDU */
    p++;
    if (len == 3) {
      apdu->le = (*p++)<<8;
      apdu->le += *p++;
      if (apdu->le == 0)
        apdu->le = 0xffff+1;
      len -= 3;
      apdu->cse = SC_APDU_CASE_2_EXT;
    }
    else {
      /* len > 3 */
      apdu->lc = (*p++)<<8;
      apdu->lc += *p++;
      len -= 3;
      if (len < apdu->lc) {
        sc_log(ctx, "APDU too short (need %zu more bytes)", apdu->lc - len);
        return SC_ERROR_INVALID_DATA;
      }
      apdu->data = p;
      apdu->datalen = apdu->lc;
      len -= apdu->lc;
      p += apdu->lc;
      if (!len) {
        apdu->cse = SC_APDU_CASE_3_EXT;
      }
      else {
        /* at this point the apdu has a Lc, so Le is on 2 bytes */
        if (len < 2) {
          sc_debug(ctx, SC_LOG_DEBUG_VERBOSE, "APDU too short (need 2 more bytes)\n");
          return SC_ERROR_INVALID_DATA;
        }
        apdu->le = (*p++)<<8;
        apdu->le += *p++;
        if (apdu->le == 0)
          apdu->le = 0xffff+1;
        len -= 2;
        apdu->cse = SC_APDU_CASE_4_EXT;
      }
    }
  }
  else {
    /* ...must be a short APDU */
    if (len == 1) {
      apdu->le = *p++;
      if (apdu->le == 0)
        apdu->le = 0xff+1;
      len--;
      apdu->cse = SC_APDU_CASE_2_SHORT;
    }
    else {
      apdu->lc = *p++;
      len--;
      if (len < apdu->lc) {
        sc_log(ctx, "APDU too short (need %zu more bytes)", apdu->lc - len);
        return SC_ERROR_INVALID_DATA;
      }
      apdu->data = p;
      apdu->datalen = apdu->lc;
      len -= apdu->lc;
      p += apdu->lc;
      if (!len) {
        apdu->cse = SC_APDU_CASE_3_SHORT;
      }
      else {
        apdu->le = *p++;
        if (apdu->le == 0)
          apdu->le = 0xff+1;
        len--;
        apdu->cse = SC_APDU_CASE_4_SHORT;
      }
    }
  }
  if (len) {
    sc_log(ctx, "APDU too long (%lu bytes extra)",(unsigned long) len);
    return SC_ERROR_INVALID_DATA;
  }

  sc_log(ctx, "Case %d %s APDU, %zu bytes:\tins=%02x p1=%02x p2=%02x lc=%04zx le=%04zx",
      apdu->cse & SC_APDU_SHORT_MASK, (apdu->cse & SC_APDU_EXT) != 0 ? "extended" : "short",
      len0, apdu->ins, apdu->p1, apdu->p2, apdu->lc, apdu->le);

  return SC_SUCCESS;
}

Coverage Report

Created: 2026-10-28 06:53