From d677f8c34657ed397c67f481056e17863d3d5341 Mon Sep 17 00:00:00 2001
From: Conor Patrick <conorpp94@gmail.com>
Date: Tue, 24 Mar 2020 17:12:46 -0400
Subject: [PATCH] add rk delete implementations

---
 fido2/device.c                 | 15 +++++++++++++++
 fido2/device.h                 |  7 +++++++
 pc/device.c                    |  6 ++++++
 targets/stm32l432/src/device.c |  7 +++++++
 4 files changed, 35 insertions(+)

diff --git a/fido2/device.c b/fido2/device.c
index 908c765..22e58f5 100644
--- a/fido2/device.c
+++ b/fido2/device.c
@@ -185,6 +185,21 @@ __attribute__((weak)) void ctap_store_rk(int index, CTAP_residentKey * rk)
 
 }
 
+__attribute__((weak)) void ctap_delete_rk(int index)
+{
+    CTAP_residentKey rk;
+
+    if (index < RK_NUM)
+    {
+        memmove(RK_STORE.rks + index, &rk, sizeof(CTAP_residentKey));
+    }
+    else
+    {
+        printf1(TAG_ERR,"Out of bounds for delete_rk\r\n");
+    }
+
+}
+
 __attribute__((weak)) void ctap_load_rk(int index, CTAP_residentKey * rk)
 {
     memmove(rk, RK_STORE.rks + index, sizeof(CTAP_residentKey));
diff --git a/fido2/device.h b/fido2/device.h
index 20029dd..0c96c73 100644
--- a/fido2/device.h
+++ b/fido2/device.h
@@ -140,6 +140,13 @@ uint32_t ctap_rk_size();
 */
 void ctap_store_rk(int index,CTAP_residentKey * rk);
 
+/** Delete a resident key from an index.
+ * @param index to delete resident key from.  Has no effect if no RK exists at index.
+ * 
+ * *Optional*, if not implemented, operates on non-persistant RK's.
+*/
+void ctap_delete_rk(int index);
+
 /** Read a resident key from an index into memory
  * @param index to read resident key from.
  * @param rk pointer to resident key structure to write into with RK.
diff --git a/pc/device.c b/pc/device.c
index c3c5905..0536bb2 100644
--- a/pc/device.c
+++ b/pc/device.c
@@ -449,6 +449,12 @@ void ctap_store_rk(int index, CTAP_residentKey * rk)
 
 }
 
+void ctap_delete_rk(int index)
+{
+    CTAP_residentKey rk;
+    memset(&rk, 0xff, sizeof(CTAP_residentKey));
+    memmove(RK_STORE.rks + index, &rk, sizeof(CTAP_residentKey));
+}
 
 void ctap_load_rk(int index, CTAP_residentKey * rk)
 {
diff --git a/targets/stm32l432/src/device.c b/targets/stm32l432/src/device.c
index e863ea5..c8f487b 100644
--- a/targets/stm32l432/src/device.c
+++ b/targets/stm32l432/src/device.c
@@ -793,6 +793,13 @@ void ctap_store_rk(int index,CTAP_residentKey * rk)
     ctap_overwrite_rk(index, rk);
 }
 
+void ctap_delete_rk(int index)
+{
+    CTAP_residentKey rk;
+    memset(&rk, 0xff, sizeof(CTAP_residentKey));
+    ctap_overwrite_rk(index, &rk);
+}
+
 void ctap_load_rk(int index,CTAP_residentKey * rk)
 {
     int byte_offset_into_page = (sizeof(CTAP_residentKey) * (index % (PAGE_SIZE/sizeof(CTAP_residentKey))));