myeid: fix EC key upload, and avoid data copying

Fixes regression from commit 3688dfe which did not consider that
the zero prefixing tests were too generic and matched EC keys too.

This simplifies the code even further and avoids data copying
when possible. Proper test is now included to do data value prefixing
only for the RSA keys it is needed.

Closes #1701.

src/libopensc/card-myeid.c

@@ -1460,36 +1460,27 @@ static int myeid_loadkey(sc_card_t *card, unsigned mode, u8* value, int value_le
  myeid_private_data_t *priv = (myeid_private_data_t *) card->drv_data;
  sc_apdu_t apdu;
  u8 sbuf[MYEID_MAX_EXT_APDU_BUFFER_SIZE];
- int r, len;
+ int r;
 
  LOG_FUNC_CALLED(card->ctx);
- len = 0;
  if (value_len == 0 || value == NULL)
  return 0;
 
- if (value[0] != 0x0 &&
- mode != LOAD_KEY_PUBLIC_EXPONENT &&
- mode != LOAD_KEY_SYMMETRIC)
- sbuf[len++] = 0x0;
-
  if (mode == LOAD_KEY_MODULUS && value_len == 256 && !priv->cap_chaining)
  {
  if ((value_len % 2) > 0 && value[0] == 0x00)
  {
  value_len--;
- memmove(value, value + 1, value_len);
+ value++;
  }
- mode = 0x88;
- len = 128;
- memcpy(sbuf,value, 128);
-
+ mode = 0x88;
  memset(&apdu, 0, sizeof(apdu));
  sc_format_apdu(card, &apdu, SC_APDU_CASE_3_SHORT, 0xDA, 0x01, mode);
 
  apdu.cla = 0x00;
- apdu.data = sbuf;
- apdu.datalen = len;
- apdu.lc = len;
+ apdu.data = value;
+ apdu.datalen = 128;
+ apdu.lc = 128;
 
  r = sc_transmit_apdu(card, &apdu);
  LOG_TEST_RET(card->ctx, r, "APDU transmit failed");
@@ -1498,23 +1489,26 @@ static int myeid_loadkey(sc_card_t *card, unsigned mode, u8* value, int value_le
  LOG_TEST_RET(card->ctx, r, "LOAD KEY returned error");
 
  mode = 0x89;
- len = value_len - 128;
- memset(&sbuf, 0, SC_MAX_APDU_BUFFER_SIZE);
- memcpy(sbuf,value + 128, value_len - 128);
+ value += 128;
+ value_len -= 128;
  }
- else
+ else if ((mode & 0xff00) == 0 && mode != LOAD_KEY_PUBLIC_EXPONENT &&
+ value[0] != 0x00)
  {
- memcpy(sbuf + len, value, value_len);
- len += value_len;
+ /* RSA components needing leading zero byte */
+ sbuf[0] = 0x0;
+ memcpy(&sbuf[1], value, value_len);
+ value = sbuf;
+ value_len ++;
  }
 
  memset(&apdu, 0, sizeof(apdu));
  sc_format_apdu(card, &apdu, SC_APDU_CASE_3_SHORT, 0xDA, 0x01, mode & 0xFF);
  apdu.flags = SC_APDU_FLAGS_CHAINING;
  apdu.cla = 0x00;
- apdu.data = sbuf;
- apdu.datalen = len;
- apdu.lc = len;
+ apdu.data = value;
+ apdu.datalen = value_len;
+ apdu.lc = value_len;
 
  r = sc_transmit_apdu(card, &apdu);
  LOG_TEST_RET(card->ctx, r, "APDU transmit failed");