ensure usb_msg_hdr contains raw message length

we want to ensure that the length of every (current or future) message
can be determined by looking at cardemu_usb_msg_hdr.msg_len, rather than
having a length that is relative to the respective specific command.

firmware/src_simtrace/card_emu.c

@@ -174,7 +174,8 @@ static void flush_rx_buffer(struct card_handle *ch)
 
  /* store length of data payload fild in header */
  rd = (struct cardemu_usb_msg_rx_data *) rctx->data;
- rd->hdr.data_len = rctx->idx;
+ rd->data_len = rctx->idx;
+ rd->hdr.msg_len = sizeof(*rd) + rd->data_len;
 
  llist_add_tail(&rctx->list, &ch->usb_tx_queue);
  req_ctx_set_state(rctx, RCTX_S_USB_TX_PENDING);
@@ -229,7 +230,8 @@ static void flush_pts(struct card_handle *ch)
 
  ptsi = (struct cardemu_usb_msg_pts_info *) rctx->data;
  ptsi->hdr.msg_type = CEMU_USB_MSGT_DO_PTS;
- ptsi->hdr.data_len = serialize_pts(ptsi->req, ch->pts.req);
+ ptsi->hdr.msg_len = sizeof(*ptsi);
+ ptsi->pts_len = serialize_pts(ptsi->req, ch->pts.req);
  serialize_pts(ptsi->resp, ch->pts.resp);
 
  llist_add_tail(&rctx->list, &ch->usb_tx_queue);
@@ -701,7 +703,7 @@ static int tx_byte_tpdu(struct card_handle *ch)
  }
 
  /* check if the buffer has now been fully transmitted */
- if ((rctx->idx >= td->hdr.data_len) ||
+ if ((rctx->idx >= td->data_len) ||
  (td->data + rctx->idx >= rctx->data + rctx->tot_len)) {
  if (td->flags & CEMU_DATA_F_PB_AND_RX) {
  /* we have just sent the procedure byte and now

firmware/src_simtrace/cardemu_prot.h

@@ -43,7 +43,8 @@ enum cardemu_usb_msg_type {
 struct cardemu_usb_msg_hdr {
  uint8_t msg_type; /* enum cardemu_usb_msg_type */
  uint8_t seq_nr; /* sequence number */
- uint16_t data_len; /* length of optional data field */
+ uint16_t msg_len; /* length of message including hdr */
+ uint8_t data[0];
 } __attribute__ ((packed));
 
 /* indicates a TPDU header is present in this message */
@@ -64,23 +65,26 @@ struct cardemu_usb_msg_cardinsert {
 /* CEMU_USB_MSGT_DT_SET_ATR */
 struct cardemu_usb_msg_set_atr {
  struct cardemu_usb_msg_hdr hdr;
- /* variable-length ATR data (hdr.data_len) */
+ uint8_t atr_len;
+ /* variable-length ATR data */
  uint8_t atr[0];
 } __attribute__ ((packed));
 
 /* CEMU_USB_MSGT_DT_TX_DATA */
 struct cardemu_usb_msg_tx_data {
  struct cardemu_usb_msg_hdr hdr;
  uint32_t flags;
- /* variable-length TPDU data (hdr.data_len) */
+ uint16_t data_len;
+ /* variable-length TPDU data */
  uint8_t data[0];
 } __attribute__ ((packed));
 
 /* CEMU_USB_MSGT_DO_RX_DATA */
 struct cardemu_usb_msg_rx_data {
  struct cardemu_usb_msg_hdr hdr;
  uint32_t flags;
- /* variable-length TPDU data (hdr.data_len) */
+ uint16_t data_len;
+ /* variable-length TPDU data */
  uint8_t data[0];
 } __attribute__ ((packed));
 
@@ -105,6 +109,7 @@ struct cardemu_usb_msg_status {
 /* CEMU_USB_MSGT_DO_PTS */
 struct cardemu_usb_msg_pts_info {
  struct cardemu_usb_msg_hdr hdr;
+ uint8_t pts_len;
  /* PTS request as sent from reader */
  uint8_t req[6];
  /* PTS response as sent by card */
@@ -117,6 +122,7 @@ struct cardemu_usb_msg_error {
  uint8_t severity;
  uint8_t subsystem;
  uint16_t code;
+ uint8_t msg_len;
  /* human-readable error message */
  uint8_t msg[0];
 } __attribute__ ((packed));

firmware/src_simtrace/mode_cardemu.c

@@ -305,7 +305,7 @@ static void dispatch_usb_command(struct req_ctx *rctx, struct cardem_inst *ci)
  break;
  case CEMU_USB_MSGT_DT_SET_ATR:
  atr = (struct cardemu_usb_msg_set_atr *) hdr;
- card_emu_set_atr(ci->ch, atr->atr, hdr->data_len);
+ card_emu_set_atr(ci->ch, atr->atr, atr->atr_len);
  req_ctx_put(rctx);
  break;
  case CEMU_USB_MSGT_DT_CARDINSERT:

firmware/test/card_emu_tests.c

@@ -140,7 +140,7 @@ static void dump_rctx(struct req_ctx *rctx)
  case CEMU_USB_MSGT_DO_RX_DATA:
  rxd = (struct cardemu_usb_msg_rx_data *)mh;
  printf(" flags=%x, data=", rxd->flags);
- for (i = 0; i < mh->data_len; i++)
+ for (i = 0; i < rxd->data_len; i++)
  printf(" %02x", rxd->data[i]);
  printf("\n");
  break;
@@ -162,13 +162,13 @@ static void get_and_verify_rctx(int state, const uint8_t *data, unsigned int len
  case RCTX_S_USB_TX_PENDING:
  td = (struct cardemu_usb_msg_tx_data *) rctx->data;
  assert(td->hdr.msg_type == CEMU_USB_MSGT_DO_RX_DATA);
- assert(td->hdr.data_len == len);
+ assert(td->data_len == len);
  assert(!memcmp(td->data, data, len));
  break;
 #if 0
  case RCTX_S_UART_RX_PENDING:
  rd = (struct cardemu_usb_msg_rx_data *) rctx->data;
- assert(rd->hdr.data_len == len);
+ assert(rd->data_len == len);
  assert(!memcmp(rd->data, data, len));
  break;
 #endif
@@ -229,8 +229,9 @@ static void host_to_device_data(const uint8_t *data, uint16_t len, unsigned int
  cardemu_hdr_set(&rd->hdr, CEMU_USB_MSGT_DT_TX_DATA);
  rd->flags = flags;
  /* copy data and set length */
- rd->hdr.data_len = len;
+ rd->data_len = len;
  memcpy(rd->data, data, len);
+ rd->hdr.msg_len = sizeof(*rd) + len;
 
  /* hand the req_ctx to the UART transmit code */
  req_ctx_set_state(rctx, RCTX_S_UART_TX_PENDING);