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/*
* Copyright (c) 2018-2022 Yubico AB. All rights reserved.
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file.
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "fido.h"
#include "packed.h"
PACKED_TYPE(frame_t,
struct frame {
uint32_t cid; /* channel id */
union {
uint8_t type;
struct {
uint8_t cmd;
uint8_t bcnth;
uint8_t bcntl;
uint8_t data[CTAP_MAX_REPORT_LEN - CTAP_INIT_HEADER_LEN];
} init;
struct {
uint8_t seq;
uint8_t data[CTAP_MAX_REPORT_LEN - CTAP_CONT_HEADER_LEN];
} cont;
} body;
})
#ifndef MIN
#define MIN(x, y) ((x) > (y) ? (y) : (x))
#endif
static int
tx_pkt(fido_dev_t *d, const void *pkt, size_t len, int *ms)
{
struct timespec ts;
int n;
if (fido_time_now(&ts) != 0)
return (-1);
n = d->io.write(d->io_handle, pkt, len);
if (fido_time_delta(&ts, ms) != 0)
return (-1);
return (n);
}
static int
tx_empty(fido_dev_t *d, uint8_t cmd, int *ms)
{
struct frame *fp;
unsigned char pkt[sizeof(*fp) + 1];
const size_t len = d->tx_len + 1;
int n;
memset(&pkt, 0, sizeof(pkt));
fp = (struct frame *)(pkt + 1);
fp->cid = d->cid;
fp->body.init.cmd = CTAP_FRAME_INIT | cmd;
if (len > sizeof(pkt) || (n = tx_pkt(d, pkt, len, ms)) < 0 ||
(size_t)n != len)
return (-1);
return (0);
}
static size_t
tx_preamble(fido_dev_t *d, uint8_t cmd, const void *buf, size_t count, int *ms)
{
struct frame *fp;
unsigned char pkt[sizeof(*fp) + 1];
const size_t len = d->tx_len + 1;
int n;
if (d->tx_len - CTAP_INIT_HEADER_LEN > sizeof(fp->body.init.data))
return (0);
memset(&pkt, 0, sizeof(pkt));
fp = (struct frame *)(pkt + 1);
fp->cid = d->cid;
fp->body.init.cmd = CTAP_FRAME_INIT | cmd;
fp->body.init.bcnth = (count >> 8) & 0xff;
fp->body.init.bcntl = count & 0xff;
count = MIN(count, d->tx_len - CTAP_INIT_HEADER_LEN);
memcpy(&fp->body.init.data, buf, count);
if (len > sizeof(pkt) || (n = tx_pkt(d, pkt, len, ms)) < 0 ||
(size_t)n != len)
return (0);
return (count);
}
static size_t
tx_frame(fido_dev_t *d, uint8_t seq, const void *buf, size_t count, int *ms)
{
struct frame *fp;
unsigned char pkt[sizeof(*fp) + 1];
const size_t len = d->tx_len + 1;
int n;
if (d->tx_len - CTAP_CONT_HEADER_LEN > sizeof(fp->body.cont.data))
return (0);
memset(&pkt, 0, sizeof(pkt));
fp = (struct frame *)(pkt + 1);
fp->cid = d->cid;
fp->body.cont.seq = seq;
count = MIN(count, d->tx_len - CTAP_CONT_HEADER_LEN);
memcpy(&fp->body.cont.data, buf, count);
if (len > sizeof(pkt) || (n = tx_pkt(d, pkt, len, ms)) < 0 ||
(size_t)n != len)
return (0);
return (count);
}
static int
tx(fido_dev_t *d, uint8_t cmd, const unsigned char *buf, size_t count, int *ms)
{
size_t n, sent;
if ((sent = tx_preamble(d, cmd, buf, count, ms)) == 0) {
fido_log_debug("%s: tx_preamble", __func__);
return (-1);
}
for (uint8_t seq = 0; sent < count; sent += n) {
if (seq & 0x80) {
fido_log_debug("%s: seq & 0x80", __func__);
return (-1);
}
if ((n = tx_frame(d, seq++, buf + sent, count - sent,
ms)) == 0) {
fido_log_debug("%s: tx_frame", __func__);
return (-1);
}
}
return (0);
}
static int
transport_tx(fido_dev_t *d, uint8_t cmd, const void *buf, size_t count, int *ms)
{
struct timespec ts;
int n;
if (fido_time_now(&ts) != 0)
return (-1);
n = d->transport.tx(d, cmd, buf, count);
if (fido_time_delta(&ts, ms) != 0)
return (-1);
return (n);
}
int
fido_tx(fido_dev_t *d, uint8_t cmd, const void *buf, size_t count, int *ms)
{
fido_log_debug("%s: dev=%p, cmd=0x%02x", __func__, (void *)d, cmd);
fido_log_xxd(buf, count, "%s", __func__);
if (d->transport.tx != NULL)
return (transport_tx(d, cmd, buf, count, ms));
if (d->io_handle == NULL || d->io.write == NULL || count > UINT16_MAX) {
fido_log_debug("%s: invalid argument", __func__);
return (-1);
}
return (count == 0 ? tx_empty(d, cmd, ms) : tx(d, cmd, buf, count, ms));
}
static int
rx_frame(fido_dev_t *d, struct frame *fp, int *ms)
{
struct timespec ts;
int n;
memset(fp, 0, sizeof(*fp));
if (fido_time_now(&ts) != 0)
return (-1);
if (d->rx_len > sizeof(*fp) || (n = d->io.read(d->io_handle,
(unsigned char *)fp, d->rx_len, *ms)) < 0 || (size_t)n != d->rx_len)
return (-1);
return (fido_time_delta(&ts, ms));
}
static int
rx_preamble(fido_dev_t *d, uint8_t cmd, struct frame *fp, int *ms)
{
do {
if (rx_frame(d, fp, ms) < 0)
return (-1);
#ifdef FIDO_FUZZ
fp->cid = d->cid;
#endif
} while (fp->cid != d->cid || (fp->cid == d->cid &&
fp->body.init.cmd == (CTAP_FRAME_INIT | CTAP_KEEPALIVE)));
if (d->rx_len > sizeof(*fp))
return (-1);
fido_log_xxd(fp, d->rx_len, "%s", __func__);
#ifdef FIDO_FUZZ
fp->body.init.cmd = (CTAP_FRAME_INIT | cmd);
#endif
if (fp->cid != d->cid || fp->body.init.cmd != (CTAP_FRAME_INIT | cmd)) {
fido_log_debug("%s: cid (0x%x, 0x%x), cmd (0x%02x, 0x%02x)",
__func__, fp->cid, d->cid, fp->body.init.cmd, cmd);
return (-1);
}
return (0);
}
static int
rx(fido_dev_t *d, uint8_t cmd, unsigned char *buf, size_t count, int *ms)
{
struct frame f;
size_t r, payload_len, init_data_len, cont_data_len;
if (d->rx_len <= CTAP_INIT_HEADER_LEN ||
d->rx_len <= CTAP_CONT_HEADER_LEN)
return (-1);
init_data_len = d->rx_len - CTAP_INIT_HEADER_LEN;
cont_data_len = d->rx_len - CTAP_CONT_HEADER_LEN;
if (init_data_len > sizeof(f.body.init.data) ||
cont_data_len > sizeof(f.body.cont.data))
return (-1);
if (rx_preamble(d, cmd, &f, ms) < 0) {
fido_log_debug("%s: rx_preamble", __func__);
return (-1);
}
payload_len = (size_t)((f.body.init.bcnth << 8) | f.body.init.bcntl);
fido_log_debug("%s: payload_len=%zu", __func__, payload_len);
if (count < payload_len) {
fido_log_debug("%s: count < payload_len", __func__);
return (-1);
}
if (payload_len < init_data_len) {
memcpy(buf, f.body.init.data, payload_len);
return ((int)payload_len);
}
memcpy(buf, f.body.init.data, init_data_len);
r = init_data_len;
for (int seq = 0; r < payload_len; seq++) {
if (rx_frame(d, &f, ms) < 0) {
fido_log_debug("%s: rx_frame", __func__);
return (-1);
}
fido_log_xxd(&f, d->rx_len, "%s", __func__);
#ifdef FIDO_FUZZ
f.cid = d->cid;
f.body.cont.seq = (uint8_t)seq;
#endif
if (f.cid != d->cid || f.body.cont.seq != seq) {
fido_log_debug("%s: cid (0x%x, 0x%x), seq (%d, %d)",
__func__, f.cid, d->cid, f.body.cont.seq, seq);
return (-1);
}
if (payload_len - r > cont_data_len) {
memcpy(buf + r, f.body.cont.data, cont_data_len);
r += cont_data_len;
} else {
memcpy(buf + r, f.body.cont.data, payload_len - r);
r += payload_len - r; /* break */
}
}
return ((int)r);
}
static int
transport_rx(fido_dev_t *d, uint8_t cmd, void *buf, size_t count, int *ms)
{
struct timespec ts;
int n;
if (fido_time_now(&ts) != 0)
return (-1);
n = d->transport.rx(d, cmd, buf, count, *ms);
if (fido_time_delta(&ts, ms) != 0)
return (-1);
return (n);
}
int
fido_rx(fido_dev_t *d, uint8_t cmd, void *buf, size_t count, int *ms)
{
int n;
fido_log_debug("%s: dev=%p, cmd=0x%02x, ms=%d", __func__, (void *)d,
cmd, *ms);
if (d->transport.rx != NULL)
return (transport_rx(d, cmd, buf, count, ms));
if (d->io_handle == NULL || d->io.read == NULL || count > UINT16_MAX) {
fido_log_debug("%s: invalid argument", __func__);
return (-1);
}
if ((n = rx(d, cmd, buf, count, ms)) >= 0)
fido_log_xxd(buf, (size_t)n, "%s", __func__);
return (n);
}
int
fido_rx_cbor_status(fido_dev_t *d, int *ms)
{
unsigned char *msg;
int msglen;
int r;
if ((msg = malloc(FIDO_MAXMSG)) == NULL) {
r = FIDO_ERR_INTERNAL;
goto out;
}
if ((msglen = fido_rx(d, CTAP_CMD_CBOR, msg, FIDO_MAXMSG, ms)) < 0 ||
(size_t)msglen < 1) {
fido_log_debug("%s: fido_rx", __func__);
r = FIDO_ERR_RX;
goto out;
}
r = msg[0];
out:
freezero(msg, FIDO_MAXMSG);
return (r);
}
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