keep SM2 config during FIDO2 reset

canokeys · Jan 2, 2024 · 0d11de4 · 0d11de4
1 parent 661030f
commit 0d11de4
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Showing 2 changed files with 21 additions and 4 deletions.
diff --git a/applets/ctap/ctap.c b/applets/ctap/ctap.c
@@ -81,10 +81,6 @@ uint8_t ctap_install(uint8_t reset) {
   if (write_attr(CTAP_CERT_FILE, KH_KEY_ATTR, kh_key, sizeof(kh_key)) < 0) return CTAP2_ERR_UNHANDLED_REQUEST;
   random_buffer(kh_key, sizeof(kh_key));
   if (write_attr(CTAP_CERT_FILE, HE_KEY_ATTR, kh_key, sizeof(kh_key)) < 0) return CTAP2_ERR_UNHANDLED_REQUEST;
-  ctap_sm2_attr.enabled = 0;
-  ctap_sm2_attr.curve_id = 9; // An unused one. See https://www.iana.org/assignments/cose/cose.xhtml#elliptic-curves
-  ctap_sm2_attr.algo_id = -48; // An unused one. See https://www.iana.org/assignments/cose/cose.xhtml#algorithms
-  if (write_attr(CTAP_CERT_FILE, SM2_ATTR, &ctap_sm2_attr, sizeof(ctap_sm2_attr)) < 0) return CTAP2_ERR_UNHANDLED_REQUEST;
   memcpy(kh_key,
          (uint8_t[]) {0x80, 0x76, 0xbe, 0x8b, 0x52, 0x8d, 0x00, 0x75, 0xf7, 0xaa, 0xe9, 0x8d, 0x6f, 0xa5, 0x7a, 0x6d,
                       0x3c}, 17);
@@ -96,6 +92,11 @@ uint8_t ctap_install(uint8_t reset) {
 
 int ctap_install_private_key(const CAPDU *capdu, RAPDU *rapdu) {
   if (LC != PRI_KEY_SIZE) EXCEPT(SW_WRONG_LENGTH);
+  // initialize SM2 config
+  ctap_sm2_attr.enabled = 0;
+  ctap_sm2_attr.curve_id = 9; // An unused one. See https://www.iana.org/assignments/cose/cose.xhtml#elliptic-curves
+  ctap_sm2_attr.algo_id = -48; // An unused one. See https://www.iana.org/assignments/cose/cose.xhtml#algorithms
+  if (write_attr(CTAP_CERT_FILE, SM2_ATTR, &ctap_sm2_attr, sizeof(ctap_sm2_attr)) < 0) return CTAP2_ERR_UNHANDLED_REQUEST;
   return write_attr(CTAP_CERT_FILE, KEY_ATTR, DATA, LC);
 }
 

diff --git a/virt-card/fabrication.c b/virt-card/fabrication.c
@@ -5,6 +5,7 @@
 #include "oath.h"
 #include "openpgp.h"
 #include "piv.h"
+#include <../applets/ctap/ctap-internal.h>
 #include <admin.h>
 #include <aes.h>
 #include <apdu.h>
@@ -62,6 +63,7 @@ static void fake_fido_personalization() {
   uint8_t c_buf[1024], r_buf[1024];
   CAPDU capdu;
   RAPDU rapdu;
+  CTAP_sm2_attr sm2_attr;
   capdu.data = c_buf;
   rapdu.data = r_buf;
 
@@ -82,6 +84,20 @@ static void fake_fido_personalization() {
   capdu.lc = sizeof(cert);
   admin_process_apdu(&capdu, &rapdu);
   assert(rapdu.sw == 0x9000);
+
+  capdu.ins = ADMIN_INS_READ_CTAP_SM2_CONFIG;
+  capdu.lc = 0;
+  admin_process_apdu(&capdu, &rapdu);
+  assert(rapdu.sw == 0x9000);
+
+  memcpy(&sm2_attr, r_buf, sizeof(sm2_attr));
+  sm2_attr.enabled = 1;
+
+  capdu.ins = ADMIN_INS_WRITE_CTAP_SM2_CONFIG;
+  capdu.data = &sm2_attr;
+  capdu.lc = sizeof(sm2_attr);
+  admin_process_apdu(&capdu, &rapdu);
+  assert(rapdu.sw == 0x9000);
 }
 
 static void fido2_init() { fake_fido_personalization(); }