Added support for signatures based on HD BIP/SLIP.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/hsm/cmd_bip_slip.c

@@ -24,6 +24,8 @@
 const uint8_t *k1_seed = (const uint8_t *)"Bitcoin seed";
 const uint8_t *p1_seed = (const uint8_t *)"Nist256p1 seed";
 const uint8_t *sym_seed = (const uint8_t *)"Symmetric key seed";
+mbedtls_ecp_keypair hd_context = {0};
+uint8_t hd_keytype = 0;
 
 int node_derive_bip_child(const mbedtls_ecp_keypair *parent, const uint8_t cpar[32], const uint8_t *i, mbedtls_ecp_keypair *child, uint8_t cchild[32]) {
     uint8_t data[1+32+4], I[64], *iL = I, *iR = I + 32;
@@ -261,5 +263,13 @@ int cmd_bip_slip() {
         }
         mbedtls_ecp_keypair_free(&ctx);
     }
+    else if (p1 == 0x10) {
+        uint8_t chain[32] = {0}, fgpt[4] = {0}, last_node[4] = {0}, nodes = 0;
+        int r = node_derive_path(apdu.data, apdu.nc, &hd_context, chain, fgpt, &nodes, last_node, &hd_keytype);
+        if (r != CCID_OK) {
+            mbedtls_ecp_keypair_free(&hd_context);
+            return SW_EXEC_ERROR();
+        }
+    }
     return SW_OK();
 }

src/hsm/cmd_signature.c

@@ -14,13 +14,16 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
-
+#include "sc_hsm.h"
 #include "crypto_utils.h"
 #include "sc_hsm.h"
 #include "asn1.h"
 #include "mbedtls/oid.h"
 #include "random.h"
 
+extern mbedtls_ecp_keypair hd_context;
+extern uint8_t hd_keytype;
+
 //-----
 /* From OpenSC */
 static const uint8_t hdr_md5[] = {
@@ -281,6 +284,25 @@ int cmd_signature() {
         res_APDU_size = olen;
         mbedtls_ecdsa_free(&ctx);
     }
+    else if (p2 == ALGO_HD) {
+        size_t olen = 0;
+        uint8_t buf[MBEDTLS_ECDSA_MAX_LEN];
+        if (hd_context.grp.id == MBEDTLS_ECP_DP_NONE) {
+            return SW_CONDITIONS_NOT_SATISFIED();
+        }
+        if (hd_keytype != 0x1 && hd_keytype != 0x2) {
+            return SW_INCORRECT_PARAMS();
+        }
+        md = MBEDTLS_MD_SHA256;
+        if (mbedtls_ecdsa_write_signature(&hd_context, md, apdu.data, apdu.nc, buf, MBEDTLS_ECDSA_MAX_LEN,
+                                          &olen, random_gen, NULL) != 0) {
+            mbedtls_ecdsa_free(&hd_context);
+            return SW_EXEC_ERROR();
+        }
+        memcpy(res_APDU, buf, olen);
+        res_APDU_size = olen;
+        mbedtls_ecdsa_free(&hd_context);
+    }
     else {
         return SW_INCORRECT_P1P2();
     }

src/hsm/sc_hsm.h

@@ -58,6 +58,7 @@ extern const uint8_t sc_hsm_aid[];
 #define ALGO_EC_DH              0x80        /* ECDH key derivation */
 #define ALGO_EC_DH_AUTPUK       0x83
 #define ALGO_EC_DH_XKEK         0x84
+#define ALGO_HD                 0xA0
 
 #define ALGO_WRAP               0x92
 #define ALGO_UNWRAP             0x93