OpenPGP: Implemented "keep alive" command

etc/opensc.conf.in

@@ -272,8 +272,9 @@ app default {
 		# can be specified as strings:
 		#
 		# rng - On-board random number source
+		# keep_alive - Request the card driver to send a "keep alive" command before each transaction to make sure that the required applet is still selected.
 		#
-		# flags = "rng", "0x80000000";
+		# flags = "rng", "keep_alive", "0x80000000";
 
 		# Enable pkcs11 initialization.
 		# Default: no
@@ -373,11 +374,30 @@ app default {
 		# notify_pin_bad_text = "bad text";
 	# }
 
-	# PIV cards need an entry similar to this one:
-	# card_atr 3B:7D:96:00:00:80:31:80:65:B0:83:11:00:AC:83:00:90:00 {
-		# name = "PIV-II";
-		# driver = "piv";
-	# }
+	# Yubikey is known to have the PIV applet and the OpenPGP applet. OpenSC
+	# can handle both to access keys and certificates, but only one at a time.
+	card_atr 3b:f8:13:00:00:81:31:fe:15:59:75:62:69:6b:65:79:34:d4 {
+		name = "Yubikey 4";
+		# Select the PKI applet to use ("PIV-II" or "openpgp")
+		driver = "PIV-II";
+		# Recover from other applications accessing a different applet
+		flags = "keep_alive";
+	}
+	card_atr 3b:fc:13:00:00:81:31:fe:15:59:75:62:69:6b:65:79:4e:45:4f:72:33:e1 {
+		name = "Yubikey Neo";
+		# Select the PKI applet to use ("PIV-II" or "openpgp")
+		driver = "PIV-II";
+		# Recover from other applications accessing a different applet
+		flags = "keep_alive";
+	}
+	card_atr 3b:8c:80:01:59:75:62:69:6b:65:79:4e:45:4f:72:33:58 {
+		atrmask = "FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:FF:00:00";
+		name = "Yubikey Neo";
+		# Select the PKI applet to use ("PIV-II" or "openpgp")
+		driver = "PIV-II";
+		# Recover from other applications accessing a different applet
+		flags = "keep_alive";
+	}
 
 	# Micardo driver sometimes only play together with T=0
 	# In theory only the 'cold' ATR should be specified, as T=0 will

src/libopensc/card-openpgp.c

@@ -2870,10 +2870,25 @@ pgp_update_binary(sc_card_t *card, unsigned int idx,
 
 static int pgp_card_reader_lock_obtained(sc_card_t *card, int was_reset)
 {
+	struct pgp_priv_data *priv = DRVDATA(card); /* may be null during initialization */
 	int r = SC_SUCCESS;
 
 	SC_FUNC_CALLED(card->ctx, SC_LOG_DEBUG_VERBOSE);
 
+	if (card->flags & SC_CARD_FLAG_KEEP_ALIVE
+			&& was_reset <= 0
+			&& priv != NULL && priv->mf && priv->mf->file) {
+		/* check whether applet is still selected */
+		unsigned char aid[16];
+
+		r = sc_get_data(card, 0x004F, aid, sizeof aid);
+		if ((size_t) r != priv->mf->file->namelen
+				|| 0 != memcmp(aid, priv->mf->file->name, r)) {
+			/* reselect is required */
+			was_reset = 1;
+		}
+	}
+
 	if (was_reset > 0) {
 		sc_file_t	*file = NULL;
 		sc_path_t	path;

src/libopensc/ctx.c

@@ -631,6 +631,8 @@ static int load_card_atrs(sc_context_t *ctx)
 
 				if (!strcmp(list->data, "rng"))
 					flags = SC_CARD_FLAG_RNG;
+				else if (!strcmp(list->data, "keep_alive"))
+					flags = SC_CARD_FLAG_KEEP_ALIVE;
 				else if (sscanf(list->data, "%x", &flags) != 1)
 					flags = 0;
 

src/libopensc/dir.c

@@ -259,10 +259,8 @@ void sc_free_apps(sc_card_t *card)
 	int	i;
 
 	for (i = 0; i < card->app_count; i++) {
-		if (card->app[i]->label)
-			free(card->app[i]->label);
-		if (card->app[i]->ddo.value)
-			free(card->app[i]->ddo.value);
+		free(card->app[i]->label);
+		free(card->app[i]->ddo.value);
 		free(card->app[i]);
 	}
 	card->app_count = -1;

src/libopensc/opensc.h

@@ -453,6 +453,7 @@ struct sc_reader_operations {
 
 /* Hint SC_CARD_CAP_RNG */
 #define SC_CARD_FLAG_RNG		0x00000002
+#define SC_CARD_FLAG_KEEP_ALIVE	0x00000004
 
 /*
  * Card capabilities

src/libopensc/pkcs15.c

@@ -790,15 +790,12 @@ sc_pkcs15_free_tokeninfo(struct sc_pkcs15_tokeninfo *tokeninfo)
 void
 sc_pkcs15_free_app(struct sc_pkcs15_card *p15card)
 {
-	if (!p15card || !p15card->app)
-		return;
-
-	if (p15card->app->label)
+	if (p15card && p15card->app) {
 		free(p15card->app->label);
-	if (p15card->app->ddo.value)
 		free(p15card->app->ddo.value);
-	free(p15card->app);
-	p15card->app = NULL;
+		free(p15card->app);
+		p15card->app = NULL;
+	}
 }