add ykpiv_fetch_object() to library

lib/ykpiv.c

@@ -602,3 +602,27 @@ ykpiv_rc ykpiv_verify(ykpiv_state *state, const char *pin, int *tries) {
     return YKPIV_GENERIC_ERROR;
   }
 }
+
+ykpiv_rc ykpiv_fetch_object(ykpiv_state *state, int object_id,
+    unsigned char *data, unsigned long *len) {
+  int sw;
+  unsigned char indata[5];
+  unsigned char templ[] = {0, YKPIV_INS_GET_DATA, 0x3b, 0xff};
+  long inlen = 5;
+
+  indata[0] = 0x5c;
+  if(object_id == YKPIV_OBJ_DISCOVERY) {
+    indata[1] = 1;
+    indata[2] = YKPIV_OBJ_DISCOVERY;
+    inlen = 3;
+  } else if(object_id > 0xffff && object_id <= 0xffffff) {
+    indata[1] = 3;
+    indata[2] = (object_id >> 16) & 0xff;
+    indata[3] = (object_id >> 8) & 0xff;
+    indata[4] = object_id & 0xff;
+  } else {
+    return YKPIV_INVALID_OBJECT;
+  }
+
+  return ykpiv_transfer_data(state, templ, indata, inlen, data, len, &sw);
+}

lib/ykpiv.h

@@ -54,6 +54,7 @@ extern "C"
 		YKPIV_KEY_ERROR = -8,
 		YKPIV_PARSE_ERROR = -9,
 		YKPIV_WRONG_PIN = -10,
+		YKPIV_INVALID_OBJECT = -11,
 	} ykpiv_rc;
 
 	const char *ykpiv_strerror(ykpiv_rc err);
@@ -77,6 +78,8 @@ extern "C"
 			unsigned char algorithm, unsigned char key);
 	ykpiv_rc ykpiv_get_version(ykpiv_state *state, char *version, size_t len);
 	ykpiv_rc ykpiv_verify(ykpiv_state *state, const char *pin, int *tries);
+	ykpiv_rc ykpiv_fetch_object(ykpiv_state *state, int object_id,
+			unsigned char *data, unsigned long *len);
 
 #define YKPIV_ALGO_3DES 0x03
 #define YKPIV_ALGO_RSA1024 0x06

lib/ykpiv.map

@@ -42,6 +42,7 @@ global:
 	ykpiv_sign_data;
 	ykpiv_get_version;
 	ykpiv_verify;
+	ykpiv_fetch_object;
 
 local:
 	*;