From b16dfbff87d3ca7c0e9d3ea29e1bf946596dc766 Mon Sep 17 00:00:00 2001
From: Bruno Vavala <bruno.vavala@intel.com>
Date: Fri, 24 May 2024 21:57:41 +0000
Subject: [PATCH] Add sgx flag checks to pservice.

This normalizes the attestation verification checks with the TP.

Signed-off-by: Bruno Vavala <bruno.vavala@intel.com>
---
 build/__tools__/generate_mrenclave_header     | 15 ++++++++++-
 .../lib/libpdo_enclave/secret_enclave.cpp     | 27 +++++++++++++------
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/build/__tools__/generate_mrenclave_header b/build/__tools__/generate_mrenclave_header
index 5522d7f8..f45440e8 100755
--- a/build/__tools__/generate_mrenclave_header
+++ b/build/__tools__/generate_mrenclave_header
@@ -30,9 +30,9 @@ parser.add_argument('--enclave', type=str, help='Name of the enclave to use in t
 
 options = parser.parse_args()
 
+# get mrenclave from metadata
 pattern_start = '^metadata->enclave_css.body.enclave_hash.m:$'
 pattern_end = '^metadata->'
-
 values = []
 with open(options.metadata, 'r') as f:
     for line in f :
@@ -43,11 +43,22 @@ with open(options.metadata, 'r') as f:
                 values.extend(list(map(lambda v : v.upper()[2:], line.strip().split(' '))))
             break
 
+def get_meta_parameter(meta_file, pattern):
+    with open(meta_file, 'r') as f:
+        for line in f :
+            if re.match(pattern, line) :
+                return line.strip().split(': ')[1]
+
+attributes_flags = get_meta_parameter(options.metadata, '^metadata->enclave_css.body.attributes.flags:')
+attribute_mask_flags = get_meta_parameter(options.metadata, '^metadata->enclave_css.body.attribute_mask.flags:')
+
 template_fields = dict()
 template_fields['mrenclave'] = ''.join(values)
 template_fields['source_file'] = options.metadata
 template_fields['timestamp'] = datetime.date.today().isoformat()
 template_fields['enclave'] = options.enclave
+template_fields['attributes_flags'] = attributes_flags
+template_fields['attribute_mask_flags'] = attribute_mask_flags
 
 with open(options.header, 'w') as f:
     f.write("""
@@ -58,4 +69,6 @@ with open(options.header, 'w') as f:
 #include "types.h"
 
 HexEncodedString {enclave}_ENCLAVE_MRENCLAVE = "{mrenclave}";
+uint64_t attributes_flags = {attributes_flags};
+uint64_t attribute_mask_flags = {attribute_mask_flags};
 """.format(**template_fields))
diff --git a/pservice/lib/libpdo_enclave/secret_enclave.cpp b/pservice/lib/libpdo_enclave/secret_enclave.cpp
index 905bfa2d..4abc032a 100644
--- a/pservice/lib/libpdo_enclave/secret_enclave.cpp
+++ b/pservice/lib/libpdo_enclave/secret_enclave.cpp
@@ -651,6 +651,7 @@ pdo_err_t VerifyEnclaveInfo(const std::string& enclaveInfo,
     sgx_report_body_t* reportBody = &quoteBody->report_body;
     sgx_report_data_t expectedReportData = *(&reportBody->report_data);
     sgx_measurement_t mrEnclaveFromReport = *(&reportBody->mr_enclave);
+    sgx_attributes_t attributes = *(&reportBody->attributes);
 
     ByteArray allowedContractMR_ENCLAVE = HexEncodedStringToByteArray(ESERVICE_ENCLAVE_MRENCLAVE);
 
@@ -676,14 +677,24 @@ pdo_err_t VerifyEnclaveInfo(const std::string& enclaveInfo,
         memcmp(computedReportData.d, expectedReportData.d, SGX_REPORT_DATA_SIZE)  != 0,
         "Invalid Report data: computedReportData does not match expectedReportData");
 
-    //Note that we do not currently verify whether the enclave debug flag is
-    //turned on or not. In order to ensure that the enclave is run in a mode
-    //that supports enhanced-confidentiality and execution integrity, the debug
-    //flag (SGX_FLAGS_DEBUG / 0x0000000000000002ULL in the report's attribute)
-    //should be set to 0. For additional details on how we plan to support this
-    //check, please see
-    //https://github.com/hyperledger-labs/private-data-objects/issues/195.
-    //
+    // Verify 64-bit enclave
+    pdo::error::ThrowIf<pdo::error::ValueError>((attributes.flags & SGX_FLAGS_MODE64BIT) == 0,
+            "Invalid 64-bit flag: 0");
+
+    // Verify SGX debug flag: check mask and enforce if necessary
+    if(attribute_mask_flags & SGX_FLAGS_DEBUG) //if bit is set, enforce debug flag check
+    {
+        pdo::error::ThrowIf<pdo::error::ValueError>(
+                (attributes.flags & SGX_FLAGS_DEBUG) != (attributes_flags & SGX_FLAGS_DEBUG),
+                "Invalid SGX debug flag");
+    }
+
+    // Note that we do not currently verify whether the TCB version of the enclave.
+    // This must be implemented to ensure that the enclave does not run using an old
+    // superseded TCB.
+    // For additional details on how we plan to support this check, please see
+    // https://github.com/hyperledger-labs/private-data-objects/issues/195.
+
     return result;
 }// VerifyEnclaveInfo