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sniff: add checksum verification for ATR and PPS

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a checksum error is only signaled in the USB message with the
corresponding flag.

Change-Id: I277868267c3199eea216ab47bdd09fb2fb944b06
This commit is contained in:
Kévin Redon
2018-07-11 10:27:13 +02:00
parent 5f6b8717a4
commit f66af0c640
3 changed files with 28 additions and 3 deletions
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1
firmware/libcommon/include/simtrace_prot.h
View File

@@ -297,6 +297,7 @@ struct st_modem_status {
/* SIMTRACE_MSGT_SNIFF_ATR, SIMTRACE_MSGT_SNIFF_PPS, SIMTRACE_MSGT_SNIFF_TPDU flags */
#define SNIFF_DATA_FLAG_ERROR_INCOMPLETE (1<<5)
#define SNIFF_DATA_FLAG_ERROR_MALFORMED (1<<6)
#define SNIFF_DATA_FLAG_ERROR_CHECKSUM (1<<7)
/* SIMTRACE_MSGT_SNIFF_CHANGE */
struct sniff_change {

26
firmware/libcommon/source/sniffer.c
View File

@@ -394,6 +394,7 @@ static void process_byte_atr(uint8_t byte)
static uint8_t atr_hist_len = 0; /* store the number of expected historical bytes */
static uint8_t y = 0; /* last mask of the upcoming TA, TB, TC, TD interface bytes */
static uint8_t i = 0; /* interface byte subgroup number */
static uint32_t flags = 0; /* error flag */
/* sanity check */
if (ISO7816_S_IN_ATR != iso_state) {
@@ -411,6 +412,7 @@ static void process_byte_atr(uint8_t byte)
/* handle ATR byte depending on current state */
switch (atr_state) {
case ATR_S_WAIT_TS: /* see ISO/IEC 7816-3:2006 section 8.1 */
flags = 0;
switch (byte) {
case 0x23: /* direct convention used, but decoded using inverse convention (a parity error should also have occurred) */
case 0x30: /* inverse convention used, but decoded using direct convention (a parity error should also have occurred) */
@@ -480,8 +482,21 @@ static void process_byte_atr(uint8_t byte)
break;
}
case ATR_S_WAIT_TCK: /* see ISO/IEC 7816-3:2006 section 8.2.5 */
/* we could verify the checksum, but we are just here to sniff */
usb_send_atr(0); /* send ATR to host software using USB */
/* verify checksum if present */
if (ATR_S_WAIT_TCK == atr_state) {
uint8_t ui;
uint8_t checksum = 0;
for (ui = 1; ui < atr_i; atr_i++) {
checksum ^= atr[ui];
}
if (checksum) {
flags |= SNIFF_DATA_FLAG_ERROR_CHECKSUM;
/* We still consider the data as valid (e.g. for WT) even is the checksum is wrong.
* It is up to the reader to handle this error (e.g. by resetting)
*/
}
}
usb_send_atr(flags); /* send ATR to host software using USB */
change_state(ISO7816_S_WAIT_TPDU); /* go to next state */
break;
default:
@@ -551,6 +566,7 @@ static void usb_send_fidi(uint8_t fidi)
static void process_byte_pps(uint8_t byte)
{
uint8_t *pps_cur; /* current PPS (request or response) */
static uint32_t flags = 0; /* error flag */
/* sanity check */
if (ISO7816_S_IN_PPS_REQ == iso_state) {
@@ -565,6 +581,7 @@ static void process_byte_pps(uint8_t byte)
/* handle PPS byte depending on current state */
switch (pps_state) { /* see ISO/IEC 7816-3:2006 section 9.2 */
case PPS_S_WAIT_PPSS: /*!< initial byte */
flags = 0;
if (0xff) {
pps_cur[0] = byte;
pps_state = PPS_S_WAIT_PPS0; /* go to next state */
@@ -613,8 +630,11 @@ static void process_byte_pps(uint8_t byte)
check ^= pps_cur[4];
}
check ^= pps_cur[5];
if (check) {
flags |= SNIFF_DATA_FLAG_ERROR_CHECKSUM;
}
pps_state = PPS_S_WAIT_END;
usb_send_pps(0); /* send PPS to host software using USB */
usb_send_pps(flags); /* send PPS to host software using USB */
if (ISO7816_S_IN_PPS_REQ == iso_state) {
if (0 == check) { /* checksum is valid */
change_state(ISO7816_S_WAIT_PPS_RSP); /* go to next state */