boxmein boxmein - 2 months ago 15
C++ Question

WinSCard SCARD_E_PROTO_MISMATCH when connecting to Estonian ID card

I am trying to read the personal file of the Estonian ID card.

I need to send the following data to the card (from
here) in order to read records from the personal file (ie ID Number, name, etc):



00 A4 00 0C # We choose root folder
00 A4 01 0C 02 EE EE # We choose folder EEEE
00 A4 02 04 02 50 44 # We choose file 5044, which contains personal data
00 B2 XX 04 # We read record XX (see table) from the personal data file
# The card responds 61 YY, where YY denotes the number of bytes waiting to be read
00 C0 00 00 YY # We read YY bytes from the card
# Card responds ... 90 00, where ... is the requested data and 90 00 means status OK


However, the raw bytes are in the T=0 protocol, and the card is stuck in T=1 for an unreasonably long time before accepting T=0. The sequence of events is as follows:


  1. Card is attached to reader

  2. Program returns from
    SCardStatusChange
    and starts handling card

  3. On trying to connect to the card (
    SCardConnect
    or
    SCardReconnect
    ) the error
    SCARD_E_SHARING_VIOLATION
    is received over and over, for around 5s

  4. Then, on trying to connect, the error
    SCARD_E_PROTO_MISMATCH
    is received for anywhere between 3 and 30 seconds, maybe more.

  5. After that, the card connects successfully and reads the data.



Can I somehow connect to it quicker in the T=0 protocol?

A simplified version of my source code is as follows:

// NOTE: this is approximately what I do.
// I haven't tested this code yet - it's almost 1 AM here.
#include <winscard.h>
void readSmartCard() {
LONG sCardErrorCode;
SCARDCONTEXT sCardContext;
DWORD sCardReaderStrLen = 1024;
wchar_t sCardReaderStr[1024];
SCARDHANDLE sCardHandle;
DWORD sCardActiveProtocol;
SCARD_READERSTATE readerState;

sCardErrorCode = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, &sCardContext);

// error handling macro

ZeroMemory(&sCardReaderState, sizeof(sCardReaderState));
sCardReaderState.szReader = L"\\\\?PnP?\\Notification";
sCardReaderState.pvUserData = nullptr;
sCardReaderState.dwEventState = SCARD_STATE_PRESENT;

sCardErrorCode = SCardGetStatusChange(sCardContext, INFINITE, &readerState, 1);

// e.h.m

if (readerState.dwCurrentState == 65538) {
sCardErrorCode = SCardListReaders(sCardContext, NULL, sCardReaderStr, &sCardReaderStrLen);
// e.h.m
readerState.szReader = sCardReaderStr;
}

sCardErrorCode = SCardGetStatusChange(sCardContext, INFINITE, &readerState, 1);
// e.h.m

if (sCardReaderState.dwEventState & SCARD_STATE_PRESENT) {

while (true) {
sCardErrorCode = SCardConnect(sCardContext, readerState.szReader, SCARD_SHARE_EXCLUSIVE,
SCARD_PROTOCOL_T0, &sCardHandle, &sCardActiveProtocol);

// e.h.m
printf("%x", sCardErrorCode);
// this will print:
// 8010000b (for around 5s)
// 8010000f (for around 20s)
if (sCardErrorCode == SCARD_S_SUCCESS) {
break;
}
Sleep(1000);
}

// open personal file and read data, yay!
}
}

Answer

After a long scouring of the internet, I discovered that no changes to the commands were necessary.

I simply needed to add an extra zero byte to the end of transmitted read/open commands, and receive the data as the response of the read command, not use a separate command to receive the bytes as well. (T=0 uses a "request data/read data" model, while T=1 just responds with the data, it seems)

I also needed to change all mentions of SCARD_PCI_T0 to conditionally use SCARD_PCI_T1 and make the SCardConnect() function accept T1 too.

I will post a decent code sample here later.

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