Endian-ness enforcement of generated compressed fabric ID (#9488)

* Endian-ness enforcement of generated compressed fabric ID

* address review comments

src/transport/FabricTable.cpp

@@ -173,9 +173,13 @@ CHIP_ERROR FabricInfo::FetchFromKVS(PersistentStorageDelegate * kvs)
 CHIP_ERROR FabricInfo::GetCompressedId(FabricId fabricId, NodeId nodeId, PeerId * compressedPeerId) const
 {
     ReturnErrorCodeIf(compressedPeerId == nullptr, CHIP_ERROR_INVALID_ARGUMENT);
-    CompressedFabricId compressedFabricId = 0;
-    MutableByteSpan fabricIdSpan(reinterpret_cast<uint8_t *>(&compressedFabricId), sizeof(compressedFabricId));
-    ReturnErrorOnFailure(GenerateCompressedFabricId(mRootPubkey, fabricId, fabricIdSpan));
+    uint8_t compressedFabricIdBuf[sizeof(uint64_t)];
+    MutableByteSpan compressedFabricIdSpan(compressedFabricIdBuf);
+    ReturnErrorOnFailure(GenerateCompressedFabricId(mRootPubkey, fabricId, compressedFabricIdSpan));
+
+    // Decode compressed fabric ID accounting for endianness, as GenerateCompressedFabricId()
+    // returns a binary buffer and is agnostic of usage of the output as an integer type.
+    CompressedFabricId compressedFabricId = Encoding::BigEndian::Get64(compressedFabricIdBuf);
     compressedPeerId->SetCompressedFabricId(compressedFabricId);
     compressedPeerId->SetNodeId(nodeId);
     return CHIP_NO_ERROR;

src/transport/FabricTable.h

@@ -124,6 +124,7 @@ class DLL_EXPORT FabricInfo
 
     // TODO - Update these APIs to take ownership of the buffer, instead of copying
     //        internally.
+    // TODO - Optimize persistent storage of NOC and Root Cert in FabricInfo.
     CHIP_ERROR SetOperationalCertsFromCertArray(const chip::ByteSpan & certArray);
     CHIP_ERROR SetRootCert(const chip::ByteSpan & cert);
 
@@ -191,6 +192,11 @@ class DLL_EXPORT FabricInfo
 
     const Crypto::P256PublicKey & GetRootPubkey() const { return mRootPubkey; }
 
+    /* Generate a compressed peer ID (containing compressed fabric ID) using provided fabric ID, node ID and
+       root public key of the fabric. The generated compressed ID is returned via compressedPeerId
+       output parameter */
+    CHIP_ERROR GetCompressedId(FabricId fabricId, NodeId nodeId, PeerId * compressedPeerId) const;
+
     friend class FabricTable;
 
 private:
@@ -232,11 +238,6 @@ class DLL_EXPORT FabricInfo
     void ReleaseOperationalCerts();
     void ReleaseRootCert();
 
-    /* Generate a compressed peer ID (containing compressed fabric ID) using provided fabric ID, node ID and
-       root public key of the fabric. The generated compressed ID is returned via compressedPeerId
-       output parameter */
-    CHIP_ERROR GetCompressedId(FabricId fabricId, NodeId nodeId, PeerId * compressedPeerId) const;
-
     struct StorableFabricInfo
     {
         uint16_t mFabric;   /* This field is serialized in LittleEndian byte order */

src/transport/tests/BUILD.gn

@@ -23,6 +23,7 @@ chip_test_suite("tests") {
   output_name = "libTransportLayerTests"
 
   test_sources = [
+    "TestFabricTable.cpp",
     "TestPeerConnections.cpp",
     "TestSecureSession.cpp",
     "TestSecureSessionMgr.cpp",

src/transport/tests/TestFabricTable.cpp

@@ -0,0 +1,131 @@
+/*
+ *
+ *    Copyright (c) 2021 Project CHIP Authors
+ *    All rights reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+/**
+ *    @file
+ *      This file implements unit tests for FabricTable implementation.
+ */
+
+#include <errno.h>
+#include <nlunit-test.h>
+
+#include <lib/core/CHIPCore.h>
+
+#include <transport/FabricTable.h>
+
+#include <lib/support/CodeUtils.h>
+#include <lib/support/UnitTestRegistration.h>
+#include <stdarg.h>
+
+using namespace chip;
+using namespace Transport;
+
+static const uint8_t sTestRootCert[] = {
+    0x15, 0x30, 0x01, 0x08, 0x59, 0xea, 0xa6, 0x32, 0x94, 0x7f, 0x54, 0x1c, 0x24, 0x02, 0x01, 0x37, 0x03, 0x27, 0x14, 0x01, 0x00,
+    0x00, 0x00, 0xca, 0xca, 0xca, 0xca, 0x18, 0x26, 0x04, 0xef, 0x17, 0x1b, 0x27, 0x26, 0x05, 0x6e, 0xb5, 0xb9, 0x4c, 0x37, 0x06,
+    0x27, 0x14, 0x01, 0x00, 0x00, 0x00, 0xca, 0xca, 0xca, 0xca, 0x18, 0x24, 0x07, 0x01, 0x24, 0x08, 0x01, 0x30, 0x09, 0x41, 0x04,
+    0x13, 0x53, 0xa3, 0xb3, 0xef, 0x1d, 0xa7, 0x08, 0xc4, 0x90, 0x80, 0x48, 0x01, 0x4e, 0x40, 0x7d, 0x59, 0x90, 0xce, 0x22, 0xbc,
+    0x4e, 0xb3, 0x3e, 0x9a, 0x5a, 0xcb, 0x25, 0xa8, 0x56, 0x03, 0xeb, 0xa6, 0xdc, 0xd8, 0x21, 0x36, 0x66, 0xa4, 0xe4, 0x4f, 0x5a,
+    0xca, 0x13, 0xeb, 0x76, 0x7f, 0xaf, 0xa7, 0xdc, 0xdd, 0xdc, 0x33, 0x41, 0x1f, 0x82, 0xa3, 0x0b, 0x54, 0x3d, 0xd1, 0xd2, 0x4b,
+    0xa8, 0x37, 0x0a, 0x35, 0x01, 0x29, 0x01, 0x18, 0x24, 0x02, 0x60, 0x30, 0x04, 0x14, 0x13, 0xaf, 0x81, 0xab, 0x37, 0x37, 0x4b,
+    0x2e, 0xd2, 0xa9, 0x64, 0x9b, 0x12, 0xb7, 0xa3, 0xa4, 0x28, 0x7e, 0x15, 0x1d, 0x30, 0x05, 0x14, 0x13, 0xaf, 0x81, 0xab, 0x37,
+    0x37, 0x4b, 0x2e, 0xd2, 0xa9, 0x64, 0x9b, 0x12, 0xb7, 0xa3, 0xa4, 0x28, 0x7e, 0x15, 0x1d, 0x18, 0x30, 0x0b, 0x40, 0x45, 0x81,
+    0x64, 0x46, 0x6c, 0x8f, 0x19, 0x5a, 0xbc, 0x0a, 0xbb, 0x7c, 0x6c, 0xb5, 0xa2, 0x7a, 0x83, 0xf4, 0x1d, 0x37, 0xf8, 0xd5, 0x3b,
+    0xee, 0xc5, 0x20, 0xab, 0xd2, 0xa0, 0xda, 0x05, 0x09, 0xb8, 0xa7, 0xc2, 0x5c, 0x04, 0x2e, 0x30, 0xcf, 0x64, 0xdc, 0x30, 0xfe,
+    0x33, 0x4e, 0x12, 0x00, 0x19, 0x66, 0x4e, 0x51, 0x50, 0x49, 0x13, 0x4f, 0x57, 0x81, 0x23, 0x84, 0x44, 0xfc, 0x75, 0x31, 0x18,
+};
+
+void TestGetCompressedFabricID(nlTestSuite * inSuite, void * inContext)
+{
+    FabricInfo fabricInfo;
+
+    fabricInfo.SetRootCert(ByteSpan(sTestRootCert));
+
+    PeerId compressedId;
+    NL_TEST_ASSERT(inSuite, fabricInfo.GetCompressedId(1234, 4321, &compressedId) == CHIP_NO_ERROR);
+
+    // We are compairing with hard coded values here (which are generated manually when the test was written)
+    // This is to ensure that the same value is generated on big endian and little endian platforms.
+    // If in this test any input to GetCompressedId() is changed, this value must be recomputed.
+    NL_TEST_ASSERT(inSuite, compressedId.GetCompressedFabricId() == 0x090F17C67be7b663);
+    NL_TEST_ASSERT(inSuite, compressedId.GetNodeId() == 4321);
+
+    NL_TEST_ASSERT(inSuite, fabricInfo.GetCompressedId(0xabcd, 0xdeed, &compressedId) == CHIP_NO_ERROR);
+
+    // We are compairing with hard coded values here (which are generated manually when the test was written)
+    // This is to ensure that the same value is generated on big endian and little endian platforms
+    // If in this test any input to GetCompressedId() is changed, this value must be recomputed.
+    NL_TEST_ASSERT(inSuite, compressedId.GetCompressedFabricId() == 0xf3fecbcec485d5d7);
+    NL_TEST_ASSERT(inSuite, compressedId.GetNodeId() == 0xdeed);
+}
+
+// Test Suite
+
+/**
+ *  Test Suite that lists all the test functions.
+ */
+// clang-format off
+static const nlTest sTests[] =
+{
+    NL_TEST_DEF("Compressed Fabric ID",    TestGetCompressedFabricID),
+    NL_TEST_SENTINEL()
+};
+// clang-format on
+
+int TestFabricTable_Setup(void * inContext);
+int TestFabricTable_Teardown(void * inContext);
+
+// clang-format off
+static nlTestSuite sSuite =
+{
+    "Test-CHIP-FabricTable",
+    &sTests[0],
+    TestFabricTable_Setup,
+    TestFabricTable_Teardown,
+};
+// clang-format on
+
+/**
+ *  Set up the test suite.
+ */
+int TestFabricTable_Setup(void * inContext)
+{
+    return chip::Platform::MemoryInit() == CHIP_NO_ERROR ? SUCCESS : FAILURE;
+}
+
+/**
+ *  Tear down the test suite.
+ */
+int TestFabricTable_Teardown(void * inContext)
+{
+    chip::Platform::MemoryShutdown();
+    return SUCCESS;
+}
+
+/**
+ *  Main
+ */
+int TestFabricTable()
+{
+    // Run test suit against one context
+    nlTestRunner(&sSuite, nullptr);
+
+    return (nlTestRunnerStats(&sSuite));
+}
+
+CHIP_REGISTER_TEST_SUITE(TestFabricTable)