[Assignment-7] (un)seal_key_pair now static functions

Assignment 7 - SGX Hands-on/src/enclave/enclave.c

@@ -0,0 +1,278 @@
+/*
+ * Copyright (C) 2011-2018 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+
+#include <stdarg.h>
+#include <stdio.h>      /* vsnprintf */
+#include <string.h>
+#include <stdlib.h>
+
+#include "Enclave.h"
+#include "Enclave_t.h"
+#include <sgx_tseal.h>
+#include <sgx_error.h>
+#include <sgx_tcrypto.h>
+
+#ifndef SK_SIZE
+#define SK_SIZE SGX_ECP256_KEY_SIZE
+#endif
+
+#ifndef PK_SIZE
+#define PK_SIZE 2*SK_SIZE
+#endif
+
+#ifndef SI_SIZE
+#define SI_SIZE 2*SK_SIZE
+#endif
+
+const sgx_ec256_public_t authorized[2] = {
+    {
+        0,
+        0
+    },
+    {
+        0,
+        0
+    }
+};
+
+int get_sealed_size() {
+    return sgx_calc_sealed_data_size(PK_SIZE, SK_SIZE);
+}
+
+int get_signature_size() {
+    return SI_SIZE;
+}
+
+int get_public_key_size() {
+    return PK_SIZE;
+}
+
+int get_private_key_size() {
+    return SK_SIZE;
+}
+
+static sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
+    // invalid parameter handling
+    if((private == NULL) || (public == NULL))
+        return SGX_ERROR_INVALID_PARAMETER;
+
+    // allocate temporary buffers on stack
+    uint8_t pk[PK_SIZE] = {0};
+    uint8_t sk[SK_SIZE] = {0};
+
+    // copy key pair into buffers
+    memcpy(pk, public->gx, PK_SIZE);
+    memcpy(sk, private->r, SK_SIZE);
+
+    // calculate needed size
+    uint32_t size = get_sealed_size();
+    if(size > sealed_size) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // seal keypair
+    return sgx_seal_data(PK_SIZE, (const uint8_t *)pk, SK_SIZE, (const uint8_t *)sk, size, (sgx_sealed_data_t *) *sealed);
+}
+
+static sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
+    // invalid parameter handling
+    if(sealed == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // allocate temporary buffers on stack
+    uint8_t pk[PK_SIZE] = {0};
+    uint8_t sk[SK_SIZE] = {0};
+    
+    // calculate public_key size and return error for unexpected results
+    uint32_t pk_size = sgx_get_add_mac_txt_len((const sgx_sealed_data_t *)sealed);
+    uint32_t sk_size = sgx_get_encrypt_txt_len((const sgx_sealed_data_t *)sealed);
+    if ((pk_size != PK_SIZE) || (sk_size != SK_SIZE)) {
+        return SGX_ERROR_UNEXPECTED;
+    }
+
+    // unseal ecc key pair
+    sgx_status_t status = sgx_unseal_data((const sgx_sealed_data_t *)sealed, pk, &pk_size, sk, &sk_size);
+    if (status != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy buffers into key structs
+    if(public != NULL) {
+        memcpy(public->gx, pk, PK_SIZE);
+    }
+    if (private != NULL) {
+        memcpy(private->r, sk, SK_SIZE);
+    }
+
+    // return success
+    return status;
+}
+
+sgx_status_t get_public_key(const uint8_t *sealed, uint32_t sealed_size, uint8_t *gx, uint32_t gx_size, uint8_t *gy, uint32_t gy_size) {
+    // invalid parameter handling
+    if((sealed == NULL) || (sealed_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // unseal public key
+    sgx_status_t status;
+    sgx_ec256_public_t public;
+    if((status = unseal_key_pair(sealed, NULL, &public)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy public key into return buffers
+    if((gx != NULL) && (gy != NULL)) {
+        memcpy(gx, public.gx, SK_SIZE);
+        memcpy(gy, public.gy, SK_SIZE);
+    }
+
+    // return success
+    return status;
+}
+
+sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, uint8_t *signature, uint32_t signature_size) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((sealed == NULL) || (sealed_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+    
+    // declare need structures
+    sgx_ecc_state_handle_t ecc_handle;
+    sgx_ec256_private_t private;
+    sgx_ec256_public_t public;
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // try unseal keypair
+    sgx_status_t seal_status;
+    if(seal_status = unseal_key_pair(sealed, &private, NULL) != SGX_SUCCESS) {
+        if((status = sgx_ecc256_create_key_pair(&private, &public, ecc_handle)) != SGX_SUCCESS) {
+            sgx_ecc256_close_context(ecc_handle);
+            return status;
+        }
+    }
+
+    // create signature
+    sgx_ec256_signature_t ecc_signature;
+    if((status = sgx_ecdsa_sign(data, data_size, &private, &ecc_signature, ecc_handle)) != SGX_SUCCESS) {
+        sgx_ecc256_close_context(ecc_handle);
+        return status;
+    }
+
+    // TODO: possible wrong endianess for other programms
+    // copy signature to return buffer
+    if((signature == NULL) || (signature_size == 0)) {
+        sgx_ecc256_close_context(ecc_handle);
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+    memcpy(signature, ecc_signature.x, SI_SIZE);
+
+    // seal the key
+    if((seal_status != SGX_SUCCESS) && (sealed != NULL)) {
+        seal_status = seal_key_pair(&private, &public, &sealed, sealed_size);
+    }
+
+    // close ecc handle and return success
+    sgx_ecc256_close_context(ecc_handle);
+    return seal_status;
+}
+
+sgx_status_t verify_firmware(const uint8_t *data, uint32_t data_size, const uint8_t *sealed, uint32_t sealed_size, const uint8_t *public_key, uint32_t public_key_size, const uint8_t *signature, uint32_t signature_size) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(((sealed == NULL) || (sealed_size == 0)) && ((public_key == NULL) || (public_key_size == 0))) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((sealed != NULL) && (public_key != NULL)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((signature == NULL) || (signature_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // declare need structures
+    sgx_ec256_signature_t ecc_signature;
+    sgx_ecc_state_handle_t ecc_handle;
+    sgx_ec256_public_t public;
+
+    // invalid signature
+    if(signature_size > SI_SIZE) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy signature into struct
+    memcpy(ecc_signature.x, signature, SI_SIZE);
+
+    // verify signature from staff or enclave
+    if(public_key != NULL) {
+        // invalid public key
+        if(public_key_size != PK_SIZE) {
+            sgx_ecc256_close_context(ecc_handle);
+            return SGX_ERROR_INVALID_PARAMETER;
+        }
+
+        // copy public key into struct
+        memcpy(public.gx, public_key, PK_SIZE);
+    } else {
+        // unseal public key
+        if(unseal_key_pair(sealed, NULL, &public) != SGX_SUCCESS) {
+            sgx_ecc256_close_context(ecc_handle);
+            return SGX_ERROR_UNEXPECTED;
+        }
+    }
+
+    // verify signature
+    uint8_t result;
+    sgx_status_t verification_status = sgx_ecdsa_verify(data, data_size, (const sgx_ec256_public_t *)&public, (const sgx_ec256_signature_t *)&ecc_signature, &result, ecc_handle);
+
+    // handle failed verification process
+    if(verification_status != SGX_SUCCESS) {
+        result = verification_status;
+    }
+
+    // close handle and return result
+    sgx_ecc256_close_context(ecc_handle);
+    return result;
+}