qemu/hw/usb/ccid-card-passthru.c
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   1/*
   2 * CCID Passthru Card Device emulation
   3 *
   4 * Copyright (c) 2011 Red Hat.
   5 * Written by Alon Levy.
   6 *
   7 * This work is licensed under the terms of the GNU GPL, version 2.1 or later.
   8 * See the COPYING file in the top-level directory.
   9 */
  10
  11#include "qemu/osdep.h"
  12#include "qemu/units.h"
  13#include <libcacard.h>
  14#include "chardev/char-fe.h"
  15#include "qemu/error-report.h"
  16#include "qemu/sockets.h"
  17#include "ccid.h"
  18#include "qapi/error.h"
  19
  20#define DPRINTF(card, lvl, fmt, ...)                    \
  21do {                                                    \
  22    if (lvl <= card->debug) {                           \
  23        printf("ccid-card-passthru: " fmt , ## __VA_ARGS__);     \
  24    }                                                   \
  25} while (0)
  26
  27#define D_WARN 1
  28#define D_INFO 2
  29#define D_MORE_INFO 3
  30#define D_VERBOSE 4
  31
  32/* TODO: do we still need this? */
  33static const uint8_t DEFAULT_ATR[] = {
  34/*
  35 * From some example somewhere
  36 * 0x3B, 0xB0, 0x18, 0x00, 0xD1, 0x81, 0x05, 0xB1, 0x40, 0x38, 0x1F, 0x03, 0x28
  37 */
  38
  39/* From an Athena smart card */
  40 0x3B, 0xD5, 0x18, 0xFF, 0x80, 0x91, 0xFE, 0x1F, 0xC3, 0x80, 0x73, 0xC8, 0x21,
  41 0x13, 0x08
  42};
  43
  44#define VSCARD_IN_SIZE      (64 * KiB)
  45
  46/* maximum size of ATR - from 7816-3 */
  47#define MAX_ATR_SIZE        40
  48
  49typedef struct PassthruState PassthruState;
  50
  51struct PassthruState {
  52    CCIDCardState base;
  53    CharBackend cs;
  54    uint8_t  vscard_in_data[VSCARD_IN_SIZE];
  55    uint32_t vscard_in_pos;
  56    uint32_t vscard_in_hdr;
  57    uint8_t  atr[MAX_ATR_SIZE];
  58    uint8_t  atr_length;
  59    uint8_t  debug;
  60};
  61
  62#define TYPE_CCID_PASSTHRU "ccid-card-passthru"
  63#define PASSTHRU_CCID_CARD(obj) \
  64    OBJECT_CHECK(PassthruState, (obj), TYPE_CCID_PASSTHRU)
  65
  66/*
  67 * VSCard protocol over chardev
  68 * This code should not depend on the card type.
  69 */
  70
  71static void ccid_card_vscard_send_msg(PassthruState *s,
  72        VSCMsgType type, uint32_t reader_id,
  73        const uint8_t *payload, uint32_t length)
  74{
  75    VSCMsgHeader scr_msg_header;
  76
  77    scr_msg_header.type = htonl(type);
  78    scr_msg_header.reader_id = htonl(reader_id);
  79    scr_msg_header.length = htonl(length);
  80    /* XXX this blocks entire thread. Rewrite to use
  81     * qemu_chr_fe_write and background I/O callbacks */
  82    qemu_chr_fe_write_all(&s->cs, (uint8_t *)&scr_msg_header,
  83                          sizeof(VSCMsgHeader));
  84    qemu_chr_fe_write_all(&s->cs, payload, length);
  85}
  86
  87static void ccid_card_vscard_send_apdu(PassthruState *s,
  88    const uint8_t *apdu, uint32_t length)
  89{
  90    ccid_card_vscard_send_msg(
  91        s, VSC_APDU, VSCARD_MINIMAL_READER_ID, apdu, length);
  92}
  93
  94static void ccid_card_vscard_send_error(PassthruState *s,
  95                    uint32_t reader_id, VSCErrorCode code)
  96{
  97    VSCMsgError msg = {.code = htonl(code)};
  98
  99    ccid_card_vscard_send_msg(
 100        s, VSC_Error, reader_id, (uint8_t *)&msg, sizeof(msg));
 101}
 102
 103static void ccid_card_vscard_send_init(PassthruState *s)
 104{
 105    VSCMsgInit msg = {
 106        .version = htonl(VSCARD_VERSION),
 107        .magic = VSCARD_MAGIC,
 108        .capabilities = {0}
 109    };
 110
 111    ccid_card_vscard_send_msg(s, VSC_Init, VSCARD_UNDEFINED_READER_ID,
 112                         (uint8_t *)&msg, sizeof(msg));
 113}
 114
 115static int ccid_card_vscard_can_read(void *opaque)
 116{
 117    PassthruState *card = opaque;
 118
 119    return VSCARD_IN_SIZE >= card->vscard_in_pos ?
 120           VSCARD_IN_SIZE - card->vscard_in_pos : 0;
 121}
 122
 123static void ccid_card_vscard_handle_init(
 124    PassthruState *card, VSCMsgHeader *hdr, VSCMsgInit *init)
 125{
 126    uint32_t *capabilities;
 127    int num_capabilities;
 128    int i;
 129
 130    capabilities = init->capabilities;
 131    num_capabilities =
 132        1 + ((hdr->length - sizeof(VSCMsgInit)) / sizeof(uint32_t));
 133    init->version = ntohl(init->version);
 134    for (i = 0 ; i < num_capabilities; ++i) {
 135        capabilities[i] = ntohl(capabilities[i]);
 136    }
 137    if (init->magic != VSCARD_MAGIC) {
 138        error_report("wrong magic");
 139        /* we can't disconnect the chardev */
 140    }
 141    if (init->version != VSCARD_VERSION) {
 142        DPRINTF(card, D_WARN,
 143            "got version %d, have %d", init->version, VSCARD_VERSION);
 144    }
 145    /* future handling of capabilities, none exist atm */
 146    ccid_card_vscard_send_init(card);
 147}
 148
 149static int check_atr(PassthruState *card, uint8_t *data, int len)
 150{
 151    int historical_length, opt_bytes;
 152    int td_count = 0;
 153    int td;
 154
 155    if (len < 2) {
 156        return 0;
 157    }
 158    historical_length = data[1] & 0xf;
 159    opt_bytes = 0;
 160    if (data[0] != 0x3b && data[0] != 0x3f) {
 161        DPRINTF(card, D_WARN, "atr's T0 is 0x%X, not in {0x3b, 0x3f}\n",
 162                data[0]);
 163        return 0;
 164    }
 165    td_count = 0;
 166    td = data[1] >> 4;
 167    while (td && td_count < 2 && opt_bytes + historical_length + 2 < len) {
 168        td_count++;
 169        if (td & 0x1) {
 170            opt_bytes++;
 171        }
 172        if (td & 0x2) {
 173            opt_bytes++;
 174        }
 175        if (td & 0x4) {
 176            opt_bytes++;
 177        }
 178        if (td & 0x8) {
 179            opt_bytes++;
 180            td = data[opt_bytes + 2] >> 4;
 181        }
 182    }
 183    if (len < 2 + historical_length + opt_bytes) {
 184        DPRINTF(card, D_WARN,
 185            "atr too short: len %d, but historical_len %d, T1 0x%X\n",
 186            len, historical_length, data[1]);
 187        return 0;
 188    }
 189    if (len > 2 + historical_length + opt_bytes) {
 190        DPRINTF(card, D_WARN,
 191            "atr too long: len %d, but hist/opt %d/%d, T1 0x%X\n",
 192            len, historical_length, opt_bytes, data[1]);
 193        /* let it through */
 194    }
 195    DPRINTF(card, D_VERBOSE,
 196            "atr passes check: %d total length, %d historical, %d optional\n",
 197            len, historical_length, opt_bytes);
 198
 199    return 1;
 200}
 201
 202static void ccid_card_vscard_handle_message(PassthruState *card,
 203    VSCMsgHeader *scr_msg_header)
 204{
 205    uint8_t *data = (uint8_t *)&scr_msg_header[1];
 206
 207    switch (scr_msg_header->type) {
 208    case VSC_ATR:
 209        DPRINTF(card, D_INFO, "VSC_ATR %d\n", scr_msg_header->length);
 210        if (scr_msg_header->length > MAX_ATR_SIZE) {
 211            error_report("ATR size exceeds spec, ignoring");
 212            ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
 213                                        VSC_GENERAL_ERROR);
 214            break;
 215        }
 216        if (!check_atr(card, data, scr_msg_header->length)) {
 217            error_report("ATR is inconsistent, ignoring");
 218            ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
 219                                        VSC_GENERAL_ERROR);
 220            break;
 221        }
 222        memcpy(card->atr, data, scr_msg_header->length);
 223        card->atr_length = scr_msg_header->length;
 224        ccid_card_card_inserted(&card->base);
 225        ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
 226                                    VSC_SUCCESS);
 227        break;
 228    case VSC_APDU:
 229        ccid_card_send_apdu_to_guest(
 230            &card->base, data, scr_msg_header->length);
 231        break;
 232    case VSC_CardRemove:
 233        DPRINTF(card, D_INFO, "VSC_CardRemove\n");
 234        ccid_card_card_removed(&card->base);
 235        ccid_card_vscard_send_error(card,
 236            scr_msg_header->reader_id, VSC_SUCCESS);
 237        break;
 238    case VSC_Init:
 239        ccid_card_vscard_handle_init(
 240            card, scr_msg_header, (VSCMsgInit *)data);
 241        break;
 242    case VSC_Error:
 243        ccid_card_card_error(&card->base, *(uint32_t *)data);
 244        break;
 245    case VSC_ReaderAdd:
 246        if (ccid_card_ccid_attach(&card->base) < 0) {
 247            ccid_card_vscard_send_error(card, VSCARD_UNDEFINED_READER_ID,
 248                                      VSC_CANNOT_ADD_MORE_READERS);
 249        } else {
 250            ccid_card_vscard_send_error(card, VSCARD_MINIMAL_READER_ID,
 251                                        VSC_SUCCESS);
 252        }
 253        break;
 254    case VSC_ReaderRemove:
 255        ccid_card_ccid_detach(&card->base);
 256        ccid_card_vscard_send_error(card,
 257            scr_msg_header->reader_id, VSC_SUCCESS);
 258        break;
 259    default:
 260        printf("usb-ccid: chardev: unexpected message of type %X\n",
 261               scr_msg_header->type);
 262        ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
 263            VSC_GENERAL_ERROR);
 264    }
 265}
 266
 267static void ccid_card_vscard_drop_connection(PassthruState *card)
 268{
 269    qemu_chr_fe_deinit(&card->cs, true);
 270    card->vscard_in_pos = card->vscard_in_hdr = 0;
 271}
 272
 273static void ccid_card_vscard_read(void *opaque, const uint8_t *buf, int size)
 274{
 275    PassthruState *card = opaque;
 276    VSCMsgHeader *hdr;
 277
 278    if (card->vscard_in_pos + size > VSCARD_IN_SIZE) {
 279        error_report("no room for data: pos %u +  size %d > %" PRId64 "."
 280                     " dropping connection.",
 281                     card->vscard_in_pos, size, VSCARD_IN_SIZE);
 282        ccid_card_vscard_drop_connection(card);
 283        return;
 284    }
 285    assert(card->vscard_in_pos < VSCARD_IN_SIZE);
 286    assert(card->vscard_in_hdr < VSCARD_IN_SIZE);
 287    memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size);
 288    card->vscard_in_pos += size;
 289    hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
 290
 291    while ((card->vscard_in_pos - card->vscard_in_hdr >= sizeof(VSCMsgHeader))
 292         &&(card->vscard_in_pos - card->vscard_in_hdr >=
 293                                  sizeof(VSCMsgHeader) + ntohl(hdr->length))) {
 294        hdr->reader_id = ntohl(hdr->reader_id);
 295        hdr->length = ntohl(hdr->length);
 296        hdr->type = ntohl(hdr->type);
 297        ccid_card_vscard_handle_message(card, hdr);
 298        card->vscard_in_hdr += hdr->length + sizeof(VSCMsgHeader);
 299        hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
 300    }
 301    if (card->vscard_in_hdr == card->vscard_in_pos) {
 302        card->vscard_in_pos = card->vscard_in_hdr = 0;
 303    }
 304}
 305
 306static void ccid_card_vscard_event(void *opaque, int event)
 307{
 308    PassthruState *card = opaque;
 309
 310    switch (event) {
 311    case CHR_EVENT_BREAK:
 312        card->vscard_in_pos = card->vscard_in_hdr = 0;
 313        break;
 314    case CHR_EVENT_OPENED:
 315        DPRINTF(card, D_INFO, "%s: CHR_EVENT_OPENED\n", __func__);
 316        break;
 317    }
 318}
 319
 320/* End VSCard handling */
 321
 322static void passthru_apdu_from_guest(
 323    CCIDCardState *base, const uint8_t *apdu, uint32_t len)
 324{
 325    PassthruState *card = PASSTHRU_CCID_CARD(base);
 326
 327    if (!qemu_chr_fe_backend_connected(&card->cs)) {
 328        printf("ccid-passthru: no chardev, discarding apdu length %d\n", len);
 329        return;
 330    }
 331    ccid_card_vscard_send_apdu(card, apdu, len);
 332}
 333
 334static const uint8_t *passthru_get_atr(CCIDCardState *base, uint32_t *len)
 335{
 336    PassthruState *card = PASSTHRU_CCID_CARD(base);
 337
 338    *len = card->atr_length;
 339    return card->atr;
 340}
 341
 342static void passthru_realize(CCIDCardState *base, Error **errp)
 343{
 344    PassthruState *card = PASSTHRU_CCID_CARD(base);
 345
 346    card->vscard_in_pos = 0;
 347    card->vscard_in_hdr = 0;
 348    if (qemu_chr_fe_backend_connected(&card->cs)) {
 349        DPRINTF(card, D_INFO, "ccid-card-passthru: initing chardev");
 350        qemu_chr_fe_set_handlers(&card->cs,
 351            ccid_card_vscard_can_read,
 352            ccid_card_vscard_read,
 353            ccid_card_vscard_event, NULL, card, NULL, true);
 354        ccid_card_vscard_send_init(card);
 355    } else {
 356        error_setg(errp, "missing chardev");
 357        return;
 358    }
 359    card->debug = parse_debug_env("QEMU_CCID_PASSTHRU_DEBUG", D_VERBOSE,
 360                                  card->debug);
 361    assert(sizeof(DEFAULT_ATR) <= MAX_ATR_SIZE);
 362    memcpy(card->atr, DEFAULT_ATR, sizeof(DEFAULT_ATR));
 363    card->atr_length = sizeof(DEFAULT_ATR);
 364}
 365
 366static VMStateDescription passthru_vmstate = {
 367    .name = "ccid-card-passthru",
 368    .version_id = 1,
 369    .minimum_version_id = 1,
 370    .fields = (VMStateField[]) {
 371        VMSTATE_BUFFER(vscard_in_data, PassthruState),
 372        VMSTATE_UINT32(vscard_in_pos, PassthruState),
 373        VMSTATE_UINT32(vscard_in_hdr, PassthruState),
 374        VMSTATE_BUFFER(atr, PassthruState),
 375        VMSTATE_UINT8(atr_length, PassthruState),
 376        VMSTATE_END_OF_LIST()
 377    }
 378};
 379
 380static Property passthru_card_properties[] = {
 381    DEFINE_PROP_CHR("chardev", PassthruState, cs),
 382    DEFINE_PROP_UINT8("debug", PassthruState, debug, 0),
 383    DEFINE_PROP_END_OF_LIST(),
 384};
 385
 386static void passthru_class_initfn(ObjectClass *klass, void *data)
 387{
 388    DeviceClass *dc = DEVICE_CLASS(klass);
 389    CCIDCardClass *cc = CCID_CARD_CLASS(klass);
 390
 391    cc->realize = passthru_realize;
 392    cc->get_atr = passthru_get_atr;
 393    cc->apdu_from_guest = passthru_apdu_from_guest;
 394    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 395    dc->desc = "passthrough smartcard";
 396    dc->vmsd = &passthru_vmstate;
 397    dc->props = passthru_card_properties;
 398}
 399
 400static const TypeInfo passthru_card_info = {
 401    .name          = TYPE_CCID_PASSTHRU,
 402    .parent        = TYPE_CCID_CARD,
 403    .instance_size = sizeof(PassthruState),
 404    .class_init    = passthru_class_initfn,
 405};
 406
 407static void ccid_card_passthru_register_types(void)
 408{
 409    type_register_static(&passthru_card_info);
 410}
 411
 412type_init(ccid_card_passthru_register_types)
 413