7e62255a4b
ATR size exceeding the limit is diagnosed, but then we merrily use it anyway, overrunning card->atr[]. The message is read from a character device. Obvious security implications unless the other end of the character device is trusted. Spotted by Coverity. CVE-2011-4111. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
341 lines
10 KiB
C
341 lines
10 KiB
C
/*
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* CCID Passthru Card Device emulation
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*
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* Copyright (c) 2011 Red Hat.
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* Written by Alon Levy.
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*
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* This work is licensed under the terms of the GNU GPL, version 2.1 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu-char.h"
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#include "qemu_socket.h"
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#include "monitor.h"
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#include "hw/ccid.h"
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#include "libcacard/vscard_common.h"
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#define DPRINTF(card, lvl, fmt, ...) \
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do { \
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if (lvl <= card->debug) { \
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printf("ccid-card-passthru: " fmt , ## __VA_ARGS__); \
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} \
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} while (0)
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#define D_WARN 1
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#define D_INFO 2
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#define D_MORE_INFO 3
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#define D_VERBOSE 4
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/* TODO: do we still need this? */
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uint8_t DEFAULT_ATR[] = {
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/*
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* From some example somewhere
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* 0x3B, 0xB0, 0x18, 0x00, 0xD1, 0x81, 0x05, 0xB1, 0x40, 0x38, 0x1F, 0x03, 0x28
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*/
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/* From an Athena smart card */
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0x3B, 0xD5, 0x18, 0xFF, 0x80, 0x91, 0xFE, 0x1F, 0xC3, 0x80, 0x73, 0xC8, 0x21,
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0x13, 0x08
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};
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#define PASSTHRU_DEV_NAME "ccid-card-passthru"
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#define VSCARD_IN_SIZE 65536
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/* maximum size of ATR - from 7816-3 */
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#define MAX_ATR_SIZE 40
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typedef struct PassthruState PassthruState;
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struct PassthruState {
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CCIDCardState base;
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CharDriverState *cs;
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uint8_t vscard_in_data[VSCARD_IN_SIZE];
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uint32_t vscard_in_pos;
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uint32_t vscard_in_hdr;
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uint8_t atr[MAX_ATR_SIZE];
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uint8_t atr_length;
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uint8_t debug;
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};
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/*
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* VSCard protocol over chardev
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* This code should not depend on the card type.
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*/
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static void ccid_card_vscard_send_msg(PassthruState *s,
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VSCMsgType type, uint32_t reader_id,
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const uint8_t *payload, uint32_t length)
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{
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VSCMsgHeader scr_msg_header;
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scr_msg_header.type = htonl(type);
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scr_msg_header.reader_id = htonl(reader_id);
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scr_msg_header.length = htonl(length);
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qemu_chr_fe_write(s->cs, (uint8_t *)&scr_msg_header, sizeof(VSCMsgHeader));
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qemu_chr_fe_write(s->cs, payload, length);
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}
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static void ccid_card_vscard_send_apdu(PassthruState *s,
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const uint8_t *apdu, uint32_t length)
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{
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ccid_card_vscard_send_msg(
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s, VSC_APDU, VSCARD_MINIMAL_READER_ID, apdu, length);
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}
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static void ccid_card_vscard_send_error(PassthruState *s,
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uint32_t reader_id, VSCErrorCode code)
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{
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VSCMsgError msg = {.code = htonl(code)};
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ccid_card_vscard_send_msg(
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s, VSC_Error, reader_id, (uint8_t *)&msg, sizeof(msg));
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}
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static void ccid_card_vscard_send_init(PassthruState *s)
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{
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VSCMsgInit msg = {
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.version = htonl(VSCARD_VERSION),
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.magic = VSCARD_MAGIC,
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.capabilities = {0}
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};
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ccid_card_vscard_send_msg(s, VSC_Init, VSCARD_UNDEFINED_READER_ID,
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(uint8_t *)&msg, sizeof(msg));
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}
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static int ccid_card_vscard_can_read(void *opaque)
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{
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PassthruState *card = opaque;
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return VSCARD_IN_SIZE >= card->vscard_in_pos ?
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VSCARD_IN_SIZE - card->vscard_in_pos : 0;
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}
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static void ccid_card_vscard_handle_init(
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PassthruState *card, VSCMsgHeader *hdr, VSCMsgInit *init)
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{
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uint32_t *capabilities;
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int num_capabilities;
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int i;
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capabilities = init->capabilities;
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num_capabilities =
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1 + ((hdr->length - sizeof(VSCMsgInit)) / sizeof(uint32_t));
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init->version = ntohl(init->version);
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for (i = 0 ; i < num_capabilities; ++i) {
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capabilities[i] = ntohl(capabilities[i]);
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}
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if (init->magic != VSCARD_MAGIC) {
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error_report("wrong magic");
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/* we can't disconnect the chardev */
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}
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if (init->version != VSCARD_VERSION) {
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DPRINTF(card, D_WARN,
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"got version %d, have %d", init->version, VSCARD_VERSION);
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}
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/* future handling of capabilities, none exist atm */
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ccid_card_vscard_send_init(card);
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}
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static void ccid_card_vscard_handle_message(PassthruState *card,
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VSCMsgHeader *scr_msg_header)
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{
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uint8_t *data = (uint8_t *)&scr_msg_header[1];
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switch (scr_msg_header->type) {
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case VSC_ATR:
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DPRINTF(card, D_INFO, "VSC_ATR %d\n", scr_msg_header->length);
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if (scr_msg_header->length > MAX_ATR_SIZE) {
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error_report("ATR size exceeds spec, ignoring");
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ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
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VSC_GENERAL_ERROR);
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break;
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}
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memcpy(card->atr, data, scr_msg_header->length);
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card->atr_length = scr_msg_header->length;
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ccid_card_card_inserted(&card->base);
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ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
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VSC_SUCCESS);
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break;
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case VSC_APDU:
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ccid_card_send_apdu_to_guest(
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&card->base, data, scr_msg_header->length);
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break;
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case VSC_CardRemove:
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DPRINTF(card, D_INFO, "VSC_CardRemove\n");
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ccid_card_card_removed(&card->base);
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ccid_card_vscard_send_error(card,
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scr_msg_header->reader_id, VSC_SUCCESS);
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break;
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case VSC_Init:
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ccid_card_vscard_handle_init(
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card, scr_msg_header, (VSCMsgInit *)data);
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break;
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case VSC_Error:
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ccid_card_card_error(&card->base, *(uint32_t *)data);
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break;
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case VSC_ReaderAdd:
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if (ccid_card_ccid_attach(&card->base) < 0) {
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ccid_card_vscard_send_error(card, VSCARD_UNDEFINED_READER_ID,
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VSC_CANNOT_ADD_MORE_READERS);
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} else {
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ccid_card_vscard_send_error(card, VSCARD_MINIMAL_READER_ID,
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VSC_SUCCESS);
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}
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break;
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case VSC_ReaderRemove:
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ccid_card_ccid_detach(&card->base);
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ccid_card_vscard_send_error(card,
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scr_msg_header->reader_id, VSC_SUCCESS);
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break;
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default:
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printf("usb-ccid: chardev: unexpected message of type %X\n",
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scr_msg_header->type);
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ccid_card_vscard_send_error(card, scr_msg_header->reader_id,
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VSC_GENERAL_ERROR);
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}
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}
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static void ccid_card_vscard_drop_connection(PassthruState *card)
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{
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qemu_chr_delete(card->cs);
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card->vscard_in_pos = card->vscard_in_hdr = 0;
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}
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static void ccid_card_vscard_read(void *opaque, const uint8_t *buf, int size)
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{
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PassthruState *card = opaque;
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VSCMsgHeader *hdr;
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if (card->vscard_in_pos + size > VSCARD_IN_SIZE) {
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error_report(
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"no room for data: pos %d + size %d > %d. dropping connection.",
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card->vscard_in_pos, size, VSCARD_IN_SIZE);
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ccid_card_vscard_drop_connection(card);
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return;
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}
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assert(card->vscard_in_pos < VSCARD_IN_SIZE);
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assert(card->vscard_in_hdr < VSCARD_IN_SIZE);
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memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size);
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card->vscard_in_pos += size;
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hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
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while ((card->vscard_in_pos - card->vscard_in_hdr >= sizeof(VSCMsgHeader))
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&&(card->vscard_in_pos - card->vscard_in_hdr >=
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sizeof(VSCMsgHeader) + ntohl(hdr->length))) {
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hdr->reader_id = ntohl(hdr->reader_id);
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hdr->length = ntohl(hdr->length);
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hdr->type = ntohl(hdr->type);
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ccid_card_vscard_handle_message(card, hdr);
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card->vscard_in_hdr += hdr->length + sizeof(VSCMsgHeader);
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hdr = (VSCMsgHeader *)(card->vscard_in_data + card->vscard_in_hdr);
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}
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if (card->vscard_in_hdr == card->vscard_in_pos) {
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card->vscard_in_pos = card->vscard_in_hdr = 0;
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}
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}
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static void ccid_card_vscard_event(void *opaque, int event)
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{
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PassthruState *card = opaque;
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switch (event) {
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case CHR_EVENT_BREAK:
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card->vscard_in_pos = card->vscard_in_hdr = 0;
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break;
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case CHR_EVENT_FOCUS:
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break;
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case CHR_EVENT_OPENED:
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DPRINTF(card, D_INFO, "%s: CHR_EVENT_OPENED\n", __func__);
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break;
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}
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}
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/* End VSCard handling */
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static void passthru_apdu_from_guest(
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CCIDCardState *base, const uint8_t *apdu, uint32_t len)
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{
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PassthruState *card = DO_UPCAST(PassthruState, base, base);
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if (!card->cs) {
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printf("ccid-passthru: no chardev, discarding apdu length %d\n", len);
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return;
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}
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ccid_card_vscard_send_apdu(card, apdu, len);
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}
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static const uint8_t *passthru_get_atr(CCIDCardState *base, uint32_t *len)
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{
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PassthruState *card = DO_UPCAST(PassthruState, base, base);
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*len = card->atr_length;
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return card->atr;
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}
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static int passthru_initfn(CCIDCardState *base)
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{
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PassthruState *card = DO_UPCAST(PassthruState, base, base);
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card->vscard_in_pos = 0;
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card->vscard_in_hdr = 0;
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if (card->cs) {
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DPRINTF(card, D_INFO, "initing chardev\n");
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qemu_chr_add_handlers(card->cs,
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ccid_card_vscard_can_read,
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ccid_card_vscard_read,
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ccid_card_vscard_event, card);
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ccid_card_vscard_send_init(card);
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} else {
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error_report("missing chardev");
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return -1;
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}
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assert(sizeof(DEFAULT_ATR) <= MAX_ATR_SIZE);
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memcpy(card->atr, DEFAULT_ATR, sizeof(DEFAULT_ATR));
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card->atr_length = sizeof(DEFAULT_ATR);
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return 0;
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}
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static int passthru_exitfn(CCIDCardState *base)
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{
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return 0;
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}
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static VMStateDescription passthru_vmstate = {
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.name = PASSTHRU_DEV_NAME,
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.version_id = 1,
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.minimum_version_id = 1,
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.fields = (VMStateField[]) {
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VMSTATE_BUFFER(vscard_in_data, PassthruState),
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VMSTATE_UINT32(vscard_in_pos, PassthruState),
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VMSTATE_UINT32(vscard_in_hdr, PassthruState),
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VMSTATE_BUFFER(atr, PassthruState),
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VMSTATE_UINT8(atr_length, PassthruState),
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VMSTATE_END_OF_LIST()
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}
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};
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static CCIDCardInfo passthru_card_info = {
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.qdev.name = PASSTHRU_DEV_NAME,
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.qdev.desc = "passthrough smartcard",
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.qdev.size = sizeof(PassthruState),
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.qdev.vmsd = &passthru_vmstate,
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.initfn = passthru_initfn,
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.exitfn = passthru_exitfn,
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.get_atr = passthru_get_atr,
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.apdu_from_guest = passthru_apdu_from_guest,
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.qdev.props = (Property[]) {
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DEFINE_PROP_CHR("chardev", PassthruState, cs),
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DEFINE_PROP_UINT8("debug", PassthruState, debug, 0),
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DEFINE_PROP_END_OF_LIST(),
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},
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};
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static void ccid_card_passthru_register_devices(void)
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{
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ccid_card_qdev_register(&passthru_card_info);
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}
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device_init(ccid_card_passthru_register_devices)
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