some working code for selecting applet

cmdline.ggo

@@ -25,3 +25,4 @@
 # for the parts of OpenSSL used as well as that of the covered work.
 
 option "verbose" v "Print more information" flag off
+option "reader" r "Only use a matching reader" string optional

yubico-piv-tool.c

@@ -29,6 +29,8 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
 
 #ifdef __APPLE__
 #include <PCSC/wintypes.h>
@@ -43,19 +45,145 @@ unsigned const char default_key[] = {
   0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
   0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
 };
+#define KEY_LEN 24
 
-typedef struct {
+unsigned const char aid[] = {
+  0xa0, 0x00, 0x00, 0x03, 0x08
+};
+#define AID_LEN 5
+
+union u_APDU {
+  struct {
     unsigned char cla;
     unsigned char ins;
     unsigned char p1;
     unsigned char p2;
     unsigned char lc;
     unsigned char data[0xff];
-} APDU;
+  } st;
+  unsigned char raw[0xff + 5];
+};
 
-static void dump_hex(const unsigned char *buf, int len) {
-  int i;
-  printf("length: %d\n", len);
+typedef union u_APDU APDU;
+
+void dump_hex(unsigned const char*, unsigned int);
+int send_data(SCARDHANDLE*, APDU, unsigned int, unsigned char*, unsigned long*, int);
+
+static bool connect_reader(SCARDHANDLE *card, SCARDCONTEXT *context, const char *wanted, int verbose) {
+  unsigned long num_readers;
+  unsigned long active_protocol;
+  char reader_buf[1024];
+  long rc;
+  char *reader_ptr;
+
+  rc = SCardEstablishContext(SCARD_SCOPE_SYSTEM, NULL, NULL, context);
+  if (rc != SCARD_S_SUCCESS) {
+    fprintf (stderr, "error: SCardEstablishContext failed, rc=%08lx\n", rc);
+    return false;
+  }
+
+  rc = SCardListReaders(*context, NULL, NULL, &num_readers);
+  if (rc != SCARD_S_SUCCESS) {
+    fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
+    SCardReleaseContext(*context);
+    return false;
+  }
+
+  if (num_readers > sizeof(reader_buf)) {
+    num_readers = sizeof(reader_buf);
+  }
+
+  rc = SCardListReaders(*context, NULL, reader_buf, &num_readers);
+  if (rc != SCARD_S_SUCCESS)
+  {
+    fprintf (stderr, "error: SCardListReaders failed, rc=%08lx\n", rc);
+    SCardReleaseContext(*context);
+    return false;
+  }
+
+  reader_ptr = reader_buf;
+  if(wanted) {
+    while(*reader_ptr != '\0') {
+      if(strstr(reader_ptr, wanted)) {
+        if(verbose) {
+          printf("using reader '%s' matching '%s'.\n", reader_ptr, wanted);
+        }
+        break;
+      } else {
+        if(verbose) {
+          printf("skipping reader '%s' since it doesn't match.\n", reader_ptr);
+        }
+        reader_ptr += strlen(reader_ptr) + 1;
+      }
+    }
+  }
+  if(*reader_ptr == '\0') {
+    fprintf (stderr, "error: no useable reader found.\n");
+    SCardReleaseContext(*context);
+    return false;
+  }
+
+  rc = SCardConnect(*context, reader_ptr, SCARD_SHARE_SHARED,
+      SCARD_PROTOCOL_T1, card, &active_protocol);
+  if(rc != SCARD_S_SUCCESS)
+  {
+    fprintf (stderr, "error: SCardConnect failed, rc=%08lx\n", rc);
+    SCardReleaseContext(*context);
+    return false;
+  }
+
+  return true;
+}
+
+static bool select_applet(SCARDHANDLE *card, int verbose) {
+  APDU apdu;
+  unsigned char data[0xff];
+  unsigned long recv_len = sizeof(data);
+  int sw;
+
+  apdu.st.cla = 0x00;
+  apdu.st.ins = 0xa4;
+  apdu.st.p1 = 0x04;
+  apdu.st.p2 = 0x00;
+  apdu.st.lc = AID_LEN;
+  memcpy(apdu.st.data, aid, AID_LEN);
+
+  sw = send_data(card, apdu, AID_LEN + 5, data, &recv_len, verbose);
+  if(sw == 0x9000) {
+    return true;
+  }
+
+  return false;
+}
+
+int send_data(SCARDHANDLE *card, APDU apdu, unsigned int send_len, unsigned char *data, unsigned long *recv_len, int verbose) {
+  long rc;
+  int sw;
+
+  if(verbose) {
+    printf("sending data: (%d bytes)\n", send_len);
+    dump_hex(apdu.raw, send_len);
+  }
+  rc = SCardTransmit(*card, SCARD_PCI_T1, apdu.raw, send_len, NULL, data, recv_len);
+  if(rc != SCARD_S_SUCCESS) {
+    fprintf (stderr, "error: SCardTransmit failed, rc=%08lx\n", rc);
+    return 0;
+  }
+
+  if(verbose) {
+    printf("received data: (%ld bytes)\n", *recv_len);
+    dump_hex(data, *recv_len);
+  }
+  if(*recv_len >= 2) {
+    sw = (data[*recv_len - 2] << 8) | data[*recv_len - 1];
+  } else {
+    sw = 0;
+  }
+  return sw;
+}
+
+void dump_hex(const unsigned char *buf, unsigned int len) {
+  unsigned int i;
   for (i = 0; i < len; i++) {
     printf("0x%02x ", buf[i]);
     if (i % 8 == 7) {
@@ -67,12 +195,20 @@ static void dump_hex(const unsigned char *buf, int len) {
 
 int main(int argc, char *argv[]) {
   struct gengetopt_args_info args_info;
+  SCARDHANDLE card;
+  SCARDCONTEXT context;
 
   if (cmdline_parser(argc, argv, &args_info) != 0) {
     return EXIT_FAILURE;
   }
 
-  dump_hex(default_key, 24);
+  if (connect_reader(&card, &context, args_info.reader_arg, args_info.verbose_flag) == false) {
+    return EXIT_FAILURE;
+  }
+
+  if (select_applet(&card, args_info.verbose_flag) == false) {
+    return EXIT_FAILURE;
+  }
 
   return EXIT_SUCCESS;
 }