Tuesday, December 16, 2014

OS X Yosemite bug: SCardReconnect

This is part of the series: "OS X Yosemite and smart cards: known bugs".


SCardReconnect() has a bad side effect on Yosemite.
After a SCardReconnect(..., SCARD_RESET_CARD, ...) the next SCardTransmit() will fail with the error code 0x80100068 that is SCARD_W_RESET_CARD.

This should not happen since SCardReconnect() should reconnect (sic) to the card after the card has been reseted.

See also

"[OSX 10.10] After connect and SCardReconnect, SCardTransmit raises card reset" https://smartcardservices.macosforge.org/trac/ticket/136

Apple bug report #19262854 "PC/SC function SCardReconnect does not work as expected". Closed by Apple, 6th January 2015, as a duplicated of #18689292.

Sample code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef __APPLE__
#include <PCSC/winscard.h>
#include <PCSC/wintypes.h>
#include <winscard.h>

int main(int argc, const char * argv[]) {
    SCARDCONTEXT hContext;
    LPSTR mszReaders;
    DWORD err = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, &hContext);
    if (err != SCARD_S_SUCCESS) {
        printf("ScardEstablishedContext: 0x%08x\n",err);
        return -1;

    DWORD cchReaders = 0;
    err = SCardListReaders(hContext, "SCard$AllReaders", NULL, &cchReaders);
    if (err != 0) {
        printf("ScardListReaders: 0x%08x\n",err);
        return -1;
    mszReaders = calloc(cchReaders, sizeof(char));
    if (!mszReaders) {
        return -1;
    err = SCardListReaders(hContext,"SCard$AllReaders", mszReaders, &cchReaders);
    if (err != SCARD_S_SUCCESS) {
        printf("ScardListReaders: 0x%08x\n",err);
        return -1;
    printf("Reader: %s\n", mszReaders);

    DWORD dwActiveProtocol;
    err = SCardConnect(hContext, mszReaders, SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1, &hCard, &dwActiveProtocol);
    if (err != SCARD_S_SUCCESS) {
        printf("ScardConnect: 0x%08x\n",err);
        return -1;

    unsigned char cmd[] = {0, 0, 0, 0};
    unsigned char resp[255];
    DWORD resp_len = sizeof resp;

    err = SCardReconnect(hCard, SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1, SCARD_RESET_CARD, &dwActiveProtocol);
    if (err != SCARD_S_SUCCESS) {
        printf("SCardReconnect: 0x%08x\n",err);

    if (SCARD_PROTOCOL_T0 == dwActiveProtocol)
        pci = SCARD_PCI_T0;
        pci = SCARD_PCI_T1;
    err = SCardTransmit(hCard, pci, cmd, sizeof cmd, pci, resp, &resp_len);
    if (err != SCARD_S_SUCCESS) {
        printf("SCardTransmit: 0x%08x\n",err);
    SCardDisconnect(hCard, SCARD_LEAVE_CARD);

    return 0;

Result (on Yosemite)

$ CFLAGS="-framework PCSC" make main
cc -framework PCSC    main.c   -o main

$ ./main 
Reader: Gemalto PC Twin Reader
SCardTransmit: 0x80100068

Expected result (on Debian)

$ CFLAGS=`pkg-config --cflags libpcsclite` LDFLAGS=`pkg-config --libs libpcsclite` make main
cc -pthread -I/usr/include/PCSC    -lpcsclite    main.c   -o main
main.c: In function ‘main’:
main.c:57:7: warning: assignment discards ‘const’ qualifier from pointer target type [enabled by default]
main.c:59:7: warning: assignment discards ‘const’ qualifier from pointer target type [enabled by default]

No error expected:
$ ./main 
Reader: Gemalto PC Twin Reader 00 00

Known workaround

You can add an second call to SCardReconnect(..., SCARD_LEAVE_CARD, ...) after the first one to force a card reconnection.

Or you can replace the bogus SCardReconnect() by the sequence:
SCardDisconnect(..., SCARD_RESET_CARD);

I could not find an elegant way to write a macro to automate the code change. The problem is that SCardConnect() needs parameters (PC/SC context and reader name) that are not available from the SCardReconnect() call.


This bug is now fixed in Mac OS X Yosemite 10.10.2.