From cb9917f7b40256b936c7b59511a9f14741055d90 Mon Sep 17 00:00:00 2001
From: Sascha Tommasone <sascha@tommasone.me>
Date: Wed, 3 Jul 2024 16:57:53 +0200
Subject: [PATCH] [Assignment-7] new function 'static sgx_status_t
 verify_signature'

---
 7-SGX_Hands-on/src/enclave/enclave.c | 33 ++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/7-SGX_Hands-on/src/enclave/enclave.c b/7-SGX_Hands-on/src/enclave/enclave.c
index 08cdee1..50bb056 100644
--- a/7-SGX_Hands-on/src/enclave/enclave.c
+++ b/7-SGX_Hands-on/src/enclave/enclave.c
@@ -161,6 +161,39 @@ sgx_status_t get_public_key(const uint8_t *sealed, uint32_t sealed_size, uint8_t
     return status;
 }
 
+static sgx_status_t verify_signature(const uint8_t *data, const uint32_t data_size, const sgx_ec256_public_t *public, const sgx_ec256_signature_t* ecc_signature) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(public == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(ecc_signature == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // declare needed structure
+    sgx_ecc_state_handle_t ecc_handle;
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // verify signature
+    uint8_t result;
+    sgx_status_t verification_status = sgx_ecdsa_verify(data, data_size, public, ecc_signature, &result, ecc_handle);
+
+    // handle failed verification process
+    if(verification_status != SGX_SUCCESS) {
+        result = verification_status;
+    }
+
+    // close context and return valid signature
+    sgx_ecc256_close_context(ecc_handle);
+    return result;
+}
+
 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)) {