Add support for dynamic VIDPID via PHY.

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

src/fido/cbor_config.c

@@ -27,6 +27,7 @@
 #include "mbedtls/ecdh.h"
 #include "mbedtls/chachapoly.h"
 #include "mbedtls/sha256.h"
+#include "file.h"
 
 extern uint8_t keydev_dec[32];
 extern bool has_keydev_dec;
@@ -35,7 +36,7 @@ int cbor_config(const uint8_t *data, size_t len) {
     CborParser parser;
     CborValue map;
     CborError error = CborNoError;
-    uint64_t subcommand = 0, pinUvAuthProtocol = 0, vendorCommandId = 0, newMinPinLength = 0;
+    uint64_t subcommand = 0, pinUvAuthProtocol = 0, vendorCommandId = 0, newMinPinLength = 0, vendorParam = 0;
     CborByteString pinUvAuthParam = { 0 }, vendorAutCt = { 0 };
     CborCharString minPinLengthRPIDs[32] = { 0 };
     size_t resp_size = 0, raw_subpara_len = 0, minPinLengthRPIDs_len = 0;
@@ -65,7 +66,7 @@ int cbor_config(const uint8_t *data, size_t len) {
             raw_subpara = (uint8_t *) cbor_value_get_next_byte(&_f1);
             CBOR_PARSE_MAP_START(_f1, 2)
             {
-                if (subcommand == 0x7f) {
+                if (subcommand == 0x7f) { // Config Aut
                     CBOR_FIELD_GET_UINT(subpara, 2);
                     if (subpara == 0x01) {
                         CBOR_FIELD_GET_UINT(vendorCommandId, 2);
@@ -74,7 +75,7 @@ int cbor_config(const uint8_t *data, size_t len) {
                         CBOR_FIELD_GET_BYTES(vendorAutCt, 2);
                     }
                 }
-                else if (subcommand == 0x03) {
+                else if (subcommand == 0x03) { // Extensions
                     CBOR_FIELD_GET_UINT(subpara, 2);
                     if (subpara == 0x01) {
                         CBOR_FIELD_GET_UINT(newMinPinLength, 2);
@@ -94,6 +95,15 @@ int cbor_config(const uint8_t *data, size_t len) {
                         CBOR_FIELD_GET_BOOL(forceChangePin, 2);
                     }
                 }
+                else  if (subcommand == 0x1B) { // PHY
+                    CBOR_FIELD_GET_UINT(subpara, 2);
+                    if (subpara == 0x01) {
+                        CBOR_FIELD_GET_UINT(vendorCommandId, 2);
+                    }
+                    else if (subpara == 0x02) {
+                        CBOR_FIELD_GET_UINT(vendorParam, 2);
+                    }
+                }
             }
             CBOR_PARSE_MAP_END(_f1, 2);
             raw_subpara_len = cbor_value_get_next_byte(&_f1) - raw_subpara;
@@ -212,6 +222,45 @@ int cbor_config(const uint8_t *data, size_t len) {
         set_opts(get_opts() | FIDO2_OPT_EA);
         goto err;
     }
+#ifndef ENABLE_EMULATION
+    else if (subcommand == 0x1B) {
+        uint8_t tmp[PHY_MAX_SIZE];
+        memset(tmp, 0, sizeof(tmp));
+        uint16_t opts = 0;
+        if (file_has_data(ef_phy)) {
+            memcpy(tmp, file_get_data(ef_phy), MIN(sizeof(tmp), file_get_size(ef_phy)));
+            if (file_get_size(ef_phy) >= 8) {
+                opts = (tmp[PHY_OPTS] << 8) | tmp[PHY_OPTS + 1];
+            }
+        }
+        if (vendorCommandId == CTAP_CONFIG_PHY_VIDPID) {
+            if (vendorParam != 0) {
+                uint8_t d[4] = { (vendorParam >> 24) & 0xFF, (vendorParam >> 16) & 0xFF, (vendorParam >> 8) & 0xFF, vendorParam & 0xFF };
+                memcpy(tmp + PHY_VID, d, sizeof(d));
+                opts |= PHY_OPT_VPID;
+            }
+            else {
+                CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
+            }
+        }
+        else if (vendorCommandId == CTAP_CONFIG_PHY_OPTS) {
+            if (vendorParam != 0) {
+                uint16_t opt = (uint16_t)vendorParam;
+                opts = (opts & ~PHY_OPT_MASK) | (opt & PHY_OPT_MASK);
+            }
+            else {
+                CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
+            }
+        }
+        else {
+            CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_OPTION);
+        }
+        tmp[PHY_OPTS] = opts >> 8;
+        tmp[PHY_OPTS + 1] = opts & 0xff;
+        file_put_data(ef_phy, tmp, sizeof(tmp));
+        low_flash_available();
+    }
+#endif
     else {
         CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_OPTION);
     }

src/fido/cbor_vendor.c

@@ -37,14 +37,7 @@ int mse_decrypt_ct(uint8_t *data, size_t len) {
     mbedtls_chachapoly_context chatx;
     mbedtls_chachapoly_init(&chatx);
     mbedtls_chachapoly_setkey(&chatx, mse.key_enc + 12);
-    int ret = mbedtls_chachapoly_auth_decrypt(&chatx,
+    int ret = mbedtls_chachapoly_auth_decrypt(&chatx, len - 16, mse.key_enc, mse.Qpt, 65, data + len - 16, data, data);
-                                              len - 16,
-                                              mse.key_enc,
-                                              mse.Qpt,
-                                              65,
-                                              data + len - 16,
-                                              data,
-                                              data);
     mbedtls_chachapoly_free(&chatx);
     return ret;
 }
@@ -112,8 +105,7 @@ int cbor_vendor_generic(uint8_t cmd, const uint8_t *data, size_t len) {
             CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, 1));
             CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x01));
 
-            CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, file_get_data(ef_keydev_enc),
+            CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, file_get_data(ef_keydev_enc), file_get_size(ef_keydev_enc)));
-                                               file_get_size(ef_keydev_enc)));
         }
         else if (vendorCmd == 0x02) {
             if (vendorParam.present == false) {
@@ -140,11 +132,7 @@ int cbor_vendor_generic(uint8_t cmd, const uint8_t *data, size_t len) {
             mbedtls_ecdh_context hkey;
             mbedtls_ecdh_init(&hkey);
             mbedtls_ecdh_setup(&hkey, MBEDTLS_ECP_DP_SECP256R1);
-            int ret = mbedtls_ecdh_gen_public(&hkey.ctx.mbed_ecdh.grp,
+            int ret = mbedtls_ecdh_gen_public(&hkey.ctx.mbed_ecdh.grp, &hkey.ctx.mbed_ecdh.d, &hkey.ctx.mbed_ecdh.Q, random_gen, NULL);
-                                              &hkey.ctx.mbed_ecdh.d,
-                                              &hkey.ctx.mbed_ecdh.Q,
-                                              random_gen,
-                                              NULL);
             mbedtls_mpi_lset(&hkey.ctx.mbed_ecdh.Qp.Z, 1);
             if (ret != 0) {
                 CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
@@ -160,37 +148,19 @@ int cbor_vendor_generic(uint8_t cmd, const uint8_t *data, size_t len) {
 
             uint8_t buf[MBEDTLS_ECP_MAX_BYTES];
             size_t olen = 0;
-            ret = mbedtls_ecp_point_write_binary(&hkey.ctx.mbed_ecdh.grp,
+            ret = mbedtls_ecp_point_write_binary(&hkey.ctx.mbed_ecdh.grp, &hkey.ctx.mbed_ecdh.Qp, MBEDTLS_ECP_PF_UNCOMPRESSED, &olen, mse.Qpt,sizeof(mse.Qpt));
-                                                 &hkey.ctx.mbed_ecdh.Qp,
-                                                 MBEDTLS_ECP_PF_UNCOMPRESSED,
-                                                 &olen,
-                                                 mse.Qpt,
-                                                 sizeof(mse.Qpt));
             if (ret != 0) {
                 mbedtls_ecdh_free(&hkey);
                 CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
             }
 
-            ret = mbedtls_ecdh_calc_secret(&hkey,
+            ret = mbedtls_ecdh_calc_secret(&hkey, &olen, buf, MBEDTLS_ECP_MAX_BYTES, random_gen, NULL);
-                                           &olen,
-                                           buf,
-                                           MBEDTLS_ECP_MAX_BYTES,
-                                           random_gen,
-                                           NULL);
             if (ret != 0) {
                 mbedtls_ecdh_free(&hkey);
                 mbedtls_platform_zeroize(buf, sizeof(buf));
                 CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
             }
-            ret = mbedtls_hkdf(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
+            ret = mbedtls_hkdf(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), NULL, 0, buf, olen, mse.Qpt, sizeof(mse.Qpt), mse.key_enc, sizeof(mse.key_enc));
-                               NULL,
-                               0,
-                               buf,
-                               olen,
-                               mse.Qpt,
-                               sizeof(mse.Qpt),
-                               mse.key_enc,
-                               sizeof(mse.key_enc));
             mbedtls_platform_zeroize(buf, sizeof(buf));
             if (ret != 0) {
                 mbedtls_ecdh_free(&hkey);
@@ -248,9 +218,7 @@ int cbor_vendor_generic(uint8_t cmd, const uint8_t *data, size_t len) {
             }
             mbedtls_x509write_csr ctx;
             mbedtls_x509write_csr_init(&ctx);
-            snprintf((char *) buffer,
+            snprintf((char *) buffer, sizeof(buffer), "C=ES,O=Pico Keys,OU=Authenticator Attestation,CN=Pico Fido EE Serial %s", pico_serial_str);
-                     sizeof(buffer),
-                     "C=ES,O=Pico Keys,OU=Authenticator Attestation,CN=Pico Fido EE Serial %s", pico_serial_str);
             mbedtls_x509write_csr_set_subject_name(&ctx, (char *) buffer);
             mbedtls_pk_context key;
             mbedtls_pk_init(&key);
@@ -258,12 +226,7 @@ int cbor_vendor_generic(uint8_t cmd, const uint8_t *data, size_t len) {
             key.pk_ctx = &ekey;
             mbedtls_x509write_csr_set_key(&ctx, &key);
             mbedtls_x509write_csr_set_md_alg(&ctx, MBEDTLS_MD_SHA256);
-            mbedtls_x509write_csr_set_extension(&ctx,
+            mbedtls_x509write_csr_set_extension(&ctx, "\x2B\x06\x01\x04\x01\x82\xE5\x1C\x01\x01\x04", 0xB, 0, aaguid, sizeof(aaguid));
-                                                "\x2B\x06\x01\x04\x01\x82\xE5\x1C\x01\x01\x04",
-                                                0xB,
-                                                0,
-                                                aaguid,
-                                                sizeof(aaguid));
             ret = mbedtls_x509write_csr_der(&ctx, buffer, sizeof(buffer), random_gen, NULL);
             mbedtls_ecdsa_free(&ekey);
             if (ret <= 0) {

src/fido/ctap.h

@@ -114,6 +114,8 @@ typedef struct {
 
 #define CTAP_CONFIG_AUT_ENABLE      0x03e43f56b34285e2
 #define CTAP_CONFIG_AUT_DISABLE     0x1831a40f04a25ed9
+#define CTAP_CONFIG_PHY_VIDPID      0x6fcb19b0cbe3acfa
+#define CTAP_CONFIG_PHY_OPTS        0x969f3b09eceb805f
 
 #define CTAP_VENDOR_CBOR            (CTAPHID_VENDOR_FIRST + 1)