From 5b9af968518344ba92b7023428280873fab1d34e Mon Sep 17 00:00:00 2001
From: Frank Morgner <frankmorgner@gmail.com>
Date: Tue, 3 Mar 2020 15:09:17 +0100
Subject: [PATCH] pkcs11: reclaim unused slots based on reader description

When a reader is removed and reattached, this re-uses the old slot
without relying on the fact that the sc_reader_t is unchanged.
---
 src/pkcs11/pkcs11-global.c |  5 ++---
 src/pkcs11/slot.c          | 46 ++++++++++++++++++++++++++++++++------
 2 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/src/pkcs11/pkcs11-global.c b/src/pkcs11/pkcs11-global.c
index 25c4cd36..95c37f3c 100644
--- a/src/pkcs11/pkcs11-global.c
+++ b/src/pkcs11/pkcs11-global.c
@@ -468,8 +468,7 @@ CK_RV C_GetSlotList(CK_BBOOL       tokenPresent,  /* only slots with token prese
 	for (i=0; i<list_size(&virtual_slots); i++) {
 		slot = (sc_pkcs11_slot_t *) list_get_at(&virtual_slots, i);
 		/* the list of available slots contains:
-		 * - if present, virtual hotplug slot;
-		 * - without token(s), one empty slot per reader;
+		 * - without token(s), at least one empty slot per reader;
 		 * - any slot with token;
 		 * - any slot that has already been seen;
 		 */
@@ -550,7 +549,7 @@ CK_RV C_GetSlotInfo(CK_SLOT_ID slotID, CK_SLOT_INFO_PTR pInfo)
 	sc_log(context, "C_GetSlotInfo(0x%lx)", slotID);
 
 	if (sc_pkcs11_conf.init_sloppy) {
-		/* Most likely virtual_slots only contains the hotplug slot and has not
+		/* Most likely virtual_slots is empty and has not
 		 * been initialized because the caller has *not* called C_GetSlotList
 		 * before C_GetSlotInfo, as required by PKCS#11.  Initialize
 		 * virtual_slots to make things work and hope the caller knows what
diff --git a/src/pkcs11/slot.c b/src/pkcs11/slot.c
index 2fb495d2..bf91b6bc 100644
--- a/src/pkcs11/slot.c
+++ b/src/pkcs11/slot.c
@@ -37,15 +37,26 @@ static struct sc_pkcs11_framework_ops *frameworks[] = {
 	NULL
 };
 
-static struct sc_pkcs11_slot * reader_get_slot(sc_reader_t *reader)
+static struct sc_pkcs11_slot * reader_reclaim_slot(sc_reader_t *reader)
 {
 	unsigned int i;
+	CK_UTF8CHAR slotDescription[64];
+	CK_UTF8CHAR manufacturerID[32];
+
+	strcpy_bp(slotDescription, reader->name, 64);
+	strcpy_bp(manufacturerID, reader->vendor, 32);
 
 	/* Locate a slot related to the reader */
 	for (i = 0; i<list_size(&virtual_slots); i++) {
 		sc_pkcs11_slot_t *slot = (sc_pkcs11_slot_t *) list_get_at(&virtual_slots, i);
 		if (slot->reader == reader)
 			return slot;
+		if (slot->reader == NULL && reader != NULL
+				&& 0 == memcmp(slot->slot_info.slotDescription, slotDescription, 64)
+				&& 0 == memcmp(slot->slot_info.manufacturerID, manufacturerID, 32)
+				&& slot->slot_info.hardwareVersion.major == reader->version_major
+				&& slot->slot_info.hardwareVersion.minor == reader->version_minor)
+			return slot;
 	}
 	return NULL;
 }
@@ -82,8 +93,8 @@ static int object_list_seeker(const void *el, const void *key)
 
 CK_RV create_slot(sc_reader_t *reader)
 {
-	/* find unused virtual hotplug slots */
-	struct sc_pkcs11_slot *slot = reader_get_slot(NULL);
+	/* find unused slots previously allocated for the same reader */
+	struct sc_pkcs11_slot *slot = reader_reclaim_slot(reader);
 
 	/* create a new slot if no empty slot is available */
 	if (!slot) {
@@ -373,11 +384,32 @@ card_detect_all(void)
 			 * possible according to PKCS#11 2.20 and later, because NSS can't
 			 * handle a shrinking slot list
 			 * https://bugzilla.mozilla.org/show_bug.cgi?id=1613632 */
+
+			/* Instead, remove the releation between reader and slot */
+			for (i = 0; i<list_size(&virtual_slots); i++) {
+				sc_pkcs11_slot_t *slot = (sc_pkcs11_slot_t *) list_get_at(&virtual_slots, i);
+				if (slot->reader == reader) {
+					slot->reader = NULL;
+				}
+			}
 		} else {
-			if (!reader_get_slot(reader))
-				initialize_reader(reader);
-			else
-				card_detect(sc_ctx_get_reader(context, i));
+			/* Locate a slot related to the reader */
+			int found = 0;
+			for (i = 0; i<list_size(&virtual_slots); i++) {
+				sc_pkcs11_slot_t *slot = (sc_pkcs11_slot_t *) list_get_at(&virtual_slots, i);
+				if (slot->reader == reader) {
+					found = 1;
+					break;
+				}
+			}
+			if (!found) {
+				for (i = 0; i < sc_pkcs11_conf.slots_per_card; i++) {
+					CK_RV rv = create_slot(reader);
+					if (rv != CKR_OK)
+						return rv;
+				}
+			}
+			card_detect(reader);
 		}
 	}
 	sc_log(context, "All cards detected");