Build 14591 (logs/482) failed on net48 with 2 test errors after the
corpus expansion in eba7fc64 added a new ECC CSR seed (request-ecc.der):
Failed FuzzGoodTestcases(AflfuzzPkcs10CertificationRequest, request-ecc.der)
Failed FuzzGoodTestcases(LibfuzzPkcs10CertificationRequest, request-ecc.der)
System.NotSupportedException : ECDSA certificate signing request
verification is not supported on this platform. Please use .NET 6.0
or later.
at Opc.Ua.Security.Certificates.Pkcs10CertificationRequest.VerifyEcdsaSignature
at Opc.Ua.Security.Certificates.Pkcs10CertificationRequest.Verify
at Opc.Ua.Fuzzing.FuzzableCode.FuzzPkcs10CertificationRequestCore
Root cause: Pkcs10CertificationRequest.VerifyEcdsaSignature throws
NotSupportedException on net48 / .NET Standard 2.x because the
implementation requires ECDsa.ImportSubjectPublicKeyInfo which is only
available on .NET 6.0+. The production code is explicit about this:
// For .NET Framework 4.8 and .NET Standard 2.x, ECDSA CSR
// verification is not supported. This is acceptable as the GDS
// Server primarily uses RSA certificates.
throw new NotSupportedException(...);
And Pkcs10CertificationRequest.Verify() likewise explicitly rethrows
NotSupportedException with a comment "Unsupported algorithm - rethrow
to inform caller".
Fix: extend the existing catch list in FuzzPkcs10CertificationRequestCore
to also swallow NotSupportedException. The fuzz harness's purpose is to
find parser bugs in the binding; platform/algorithm gaps that production
code already documents as intentional are not findings. An inline
comment records the reasoning so this stays correct under future
refactors.
Scope: only FuzzableCode.Pkcs10.cs is touched. No other Fuzz target hit
NotSupportedException in the CI run, and Pkcs10CertificationRequest.Verify
is the only production caller that intentionally rethrows it through any
of these fuzz code paths.
Verified locally:
- Certificates.Fuzz.Tests net48: 460 / 0 failed (previously 2 failed)
- Certificates.Fuzz.Tests net10: 460 / 0 failed
- Encoders.Fuzz.Tests net48: 4131 / 0 failed
- Encoders.Fuzz.Tests net10: 4131 / 0 failed
- Network.Fuzz.Tests net10: 330 / 0 failed
- Network.Fuzz.Tests net48: N/A (project targets net8.0/net9.0/net10.0 only)
Total 5381 tests, 0 failures across the affected TFM matrix.
# Description
Broadens fuzz coverage across the highest-value untrusted-input surfaces
in the stack, refactors the per-area scaffolding so adding a new fuzz
area is a copy-paste-replace operation, and integrates everything into
`UA.slnx`, `Fuzzing/Fuzzing.md`, and `Docs/README.md`.
**Totals**: 143 files, +4961 / −289. Source plan:
`plans/27-fuzzing-coverage-expansion.md` (added in this PR).
### Shared scaffolding (refactor, no behaviour change)
* Extract generic NUnit replay harness from
`Encoders/Fuzz.Tests/EncoderTests.cs` into
`Fuzzing/common/Fuzz.Tests/{FuzzTargetTestsBase,FuzzTargetFunction,TestcaseAsset,TestAssetUtils}.cs`.
* Each area's `Fuzz.Tests` becomes a thin subclass binding its own
`FuzzableCode` type.
* Hardcoded testcase-suffix arrays replaced with `Testcases.*` directory
discovery at runtime.
* New `Fuzzing/scripts/fuzz-menu.ps1`: dynamic target menu enumerating
`FuzzableCode` statics via reflection — no more hardcoded target lists
in `libfuzz.bat` / `aflfuzz.sh`.
### Encoders area hardening
* **Bug fix**: `AflfuzzXmlEncoder` was re-encoding via `JsonEncoder`;
now uses `XmlEncoder` (the `LibfuzzXmlEncoder` variant was already
correct).
* Add idempotent JSON / XML targets mirroring the existing Binary
idempotent pattern.
* Add compact-JSON encoder option coverage (`JsonEncoderOptions.None`
alongside `Verbose`).
* New `FuzzableCode.BuiltInTypes.cs` (48 targets): `NodeId`,
`ExpandedNodeId`, `Variant`, `ExtensionObject`, `DataValue`,
`DiagnosticInfo`, `QualifiedName`, `LocalizedText` × Binary/JSON/XML
decoders.
* Enrich `Encoders.Testcases.cs` seed corpus with `BrowseRequest` +
`WriteRequest`.
* New `Fuzzing/dictionaries/binary.dict`.
### String parsers (folded into Encoders area)
* New `FuzzableCode.Parsers.cs` (12 targets): `NodeId.Parse`,
`ExpandedNodeId.Parse`, `RelativePathFormatter.Parse`,
`QualifiedName.Parse`, `NumericRange.Parse`, `Uuid` round-trip (both
afl-string and libFuzzer-span signatures).
* New `Fuzzing/dictionaries/nodeid.dict`.
### Certificates / CRL / ASN.1 (NEW area)
* New `Fuzzing/Certificates/{Fuzz,Fuzz.Tests,Fuzz.Tools}` referencing
`Opc.Ua.Security.Certificates` + `Opc.Ua.Core`.
* Targets (20 total): `X509CRL(byte[])` → `EnsureDecoded`,
`X509SubjectAltNameExtension` / `X509AuthorityKeyIdentifierExtension` /
`X509CrlNumberExtension` raw-ASN.1 decoders,
`PEMReader.ImportPublicKeysFromPEM` / `ImportRsaPrivateKeyFromPEM`,
`Pkcs10CertificationRequest`, `AsnUtils.ParseX509Blob` + `AsnReader`
sequence/integer helpers.
* `Certificates.Testcases.cs` builds an RSA cert / CRL / CSR with the
existing builders and emits raw DER + PEM seeds.
* New `Fuzzing/dictionaries/asn1.dict` (DER tags, context-class tags,
length-form sentinels, OID prefixes).
### Network area via `Opc.Ua.Bindings.Pcap` (NO Core changes, NEW area)
* New `Fuzzing/Network/{Fuzz,Fuzz.Tests,Fuzz.Tools}`, multi-targeted
`net8.0;net9.0;net10.0` to match the pcap binding matrix (excluded from
net48/net472).
* **Stateless targets**: `OpcUaFrameParser.Process` (TCP segment → UA-SC
chunk splitter), `TcpStreamReassembler.Process` (raw TCP reassembly),
`OfflineSecureChannel.ReadChunk` (UA-SC symmetric decrypt + verify via
`UaSCUaBinaryChannel.ReadSymmetricMessage` → every security profile
covered through the binding), `ServiceCallReassembler.Push` (chunk →
decoded service call).
* **Stateful libFuzzer-only targets**: `MockServerReplay` /
`MockClientReplay` drivers in a separate target list so cheap stateless
targets dominate throughput.
* Deterministic test-only `ChannelKeyMaterial` via
`SecurityPolicies.None`.
* `Network.Testcases.cs` emits synthetic Hello/Ack/Err/Rhe/MSG seeds via
`LoopbackFrameBuilder`. Live handshake recorder is out of scope for this
PR (degraded mode documented).
* `Network.Fuzz` host does **not** instantiate `NicCaptureSource` — the
AFL/libFuzzer process never opens raw sockets.
* New `Fuzzing/dictionaries/uasc.dict` (MSG/OPN/CLO/HEL/ACK/ERR/RHE
magic + chunk-type bytes + security-policy URI prefixes) and `tcp.dict`
(Ethernet/IPv4/TCP framing markers).
### `Opc.Ua.Core` UA-SC parse seam (complements 4a)
* New `Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageParsers.cs` — `internal
static` helpers for the pre-crypto, pre-auth chunk surface NOT covered
by the pcap binding: `TryParseChunkHeader`, `ReadHelloMessage`,
`ReadAcknowledgeMessage`, `ReadErrorMessage`, `ReadReverseHelloMessage`,
`ReadAsymmetricMessageHeader`.
* **No production-code refactor** (Strategy B): the new internal helpers
are an independent parse seam, not a refactor of the entangled private
channel methods. Existing `ProcessHelloMessage` /
`ProcessReverseHelloMessage` / asym-header decode paths are untouched.
Behaviour is byte-identical (verified — Opc.Ua.Core.Tests Tcp subset 7/7
passing).
* Surface via `<InternalsVisibleTo Include="Network.Fuzz" />` (+
matching Tools and Tests entries because the linked
`FuzzableCode.Transport.cs` compiles from all three host projects).
* New `Fuzzing/Network/Fuzz/FuzzableCode.Transport.cs` (12 targets) +
`Fuzzing/Network/Fuzz.Tools/Transport.Testcases.cs` (seeds under
`Testcases.Tcp.*`).
### Integration
* `UA.slnx`: add the 6 new fuzz projects, 4 new shared harness `.cs`
files, 5 new dictionaries, and the new `fuzz-menu.ps1` script — all
under the right `/Fuzzing/<Area>/` solution folders.
* Rewrite `Fuzzing/Fuzzing.md`: areas table, per-area dictionaries,
dynamic target-menu, step-by-step "how to add a new fuzz area" recipe,
Network area's replay-driven seed pipeline + key-material discipline,
pcap binding dependency note.
* Cross-link from `Docs/README.md` to `Fuzzing/Fuzzing.md`.
* Fix `.Order()` → `.OrderBy()` in shared scaffolding
(`.Order(IComparer)` is net7+; the harness compiles on net48/net472 for
the Encoders + Certificates test matrices).
## Verification
| Project | TFM | Tests | Result |
|---|---|---|---|
| `Encoders.Fuzz.Tests` | net10.0 | 4131 | ✅ 0 failed |
| `Certificates.Fuzz.Tests` | net10.0 | 220 | ✅ 0 failed |
| `Network.Fuzz.Tests` | net10.0 | 330 | ✅ 0 failed |
| **Total** | | **4681** | **✅ 0 failed** |
* Full `dotnet build UA.slnx` (all TFMs, including
net48/net472/net8/net9/net10): **0 errors**, warning count unchanged
from baseline.
* `Network.Fuzz` multi-TFM build: **net8.0 + net9.0 + net10.0** all
green.
* `Opc.Ua.Core` build: **0 errors, 0 warnings** after Phase 4b seam
addition.
## Notes for reviewers
* **Base branch**: `channelrefinements2`, not `master`. The pcap binding
(`Stack/Opc.Ua.Bindings.Pcap`) only exists on the channelrefinements
line.
* **Real keylog / key material**: never committed. All Network seed
corpora use deterministic material generated from fixture test
certificates via the binding's own replay helpers.
* **`.der` test assets**: force-added with `git add -f` (consistent with
the existing intentional exception at
`Tests/Opc.Ua.Security.Certificates.Tests/Assets/OPC Foundation Root CA
[...].der`); the repo-wide `*.der` gitignore otherwise excludes them.
* **Out of scope** (documented as fold-ins for future work):
`PcapFileReader` / `PcapNgFileWriter` / `UaKeyLogTextReader` /
`UaKeyLogJsonReader` defensive parser fuzzing; live handshake recorder
for `Network.Testcases.cs`; real loopback replay drivers (current
implementation uses synthetic replay).
## Checklist
- [ ] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed. _(Fuzz
suites verified on net10.0: 4681/4681 passing. Full UA.slnx build green
on all TFMs. Full repo-wide test run not yet executed on net48 —
pre-existing tests unaffected by these changes; only
`Stack/Opc.Ua.Core/Stack/Tcp/TcpMessageParsers.cs` is new and is gated
behind `<InternalsVisibleTo>`.)_
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [ ] I have addressed **all** PR feedback received.
Two refactors that together reshape how the stack tier is laid out:
1. Rename `Opc.Ua` project to `Opc.Ua.Core.Types`
* Stack/Opc.Ua/ -> Stack/Opc.Ua.Core.Types/ (git mv preserves history)
* Opc.Ua.csproj -> Opc.Ua.Core.Types.csproj
* AssemblyName : `Opc.Ua` -> `Opc.Ua.Core.Types`
* PackageId : `OPCFoundation.NetStandard.Opc.Ua` ->
`OPCFoundation.NetStandard.Opc.Ua.Core.Types`
* RootNamespace : kept as `Opc.Ua`
* StackGeneration.cs assembly-name switch updated; the renamed
assembly still produces `StackGenerationType.Models`.
* The `OPCFoundation.NetStandard.Opc.Ua` name now belongs solely to
the roll-up meta-package (nuget/Opc.Ua.nuspec); the meta-package's
former self-dependency is replaced with the new
`.Core.Types` package, and `.Symbols.nuspec` gains the
matching `.Core.Types.Debug` debug-symbol dependency.
2. Move `Opc.Ua.Security.Certificates` from Libraries/ to Stack/
It is a stack-tier dependency consumed by Opc.Ua.Core, not a
higher-level library extension, so it now sits alongside the other
stack projects.
Both refactors update the same set of cross-cutting infrastructure:
- UA.slnx, UA Core Library.slnx, Applications/ConsoleReferenceServer/Dockerfile
- .azurepipelines/signlist{Debug,Release}.txt
- ProjectReferences across Stack/, Libraries/, Tests/, Fuzzing/
- Tests/Opc.Ua.SourceGeneration.Stack.Tests/StackGenerationAssemblyTests.cs
- Docs/PlatformBuild.md and .github/copilot-instructions.md (new
Core.Types package listed)
Verification
* dotnet build UA.slnx -c Debug -- succeeded, 0 errors
* StackGenerationAssemblyTests : 5 passed
* Opc.Ua.SourceGeneration.Tests : 40 passed
* Opc.Ua.SourceGeneration.Core.Tests : 3514 passed, 8 skipped
* Opc.Ua.Core.Tests (Stack filter) : 1982 passed, 80 skipped
* Opc.Ua.Security.Certificates.Tests : 239 passed
* New certificate and secrete abstraction with certificate infrastructure and certificate/secret stores.
* leak testing for certificate resources to validate new ref counting in every test assembly
* Migration guide updated and documentation added for all
* Remove IDisposable from Nodestate and UserIdentity.
* UserCertificateTokenHandler now just points into certificate registry/stores, no dispose required
* Fix CA2000 warnings and cleanup of other diagnostics, increase warning levels in .editorconfig
* make most ptojects aot compatible
* Remove newtonsoft
* Migrate all projects from Mono.Options to System.CommandLine 2.0.5
* Fix array clone
* Replace serializers for storage using new attribute driven type geberator
* Add new AOT integration tests covering all functional areas
* Documentation updates
Generate stack and application code using source generators
Change built in types to readonly structs
Update localized text implementation to use JSON text serializer
Status code with symbolic names
Immutable node ids
No boxing for all built in types <= 8 bytes in Variant.
Split user identity token and token handling via token handler
Add migration guide for breaking changes
This pull request modernizes the OPC UA .NET codebase and tests, removes .NET Standard 2.0 support from certificate/security code, and updates test code to use C# 12 and .NET 8+ features for clarity and maintainability.
- Certificate and BouncyCastle interop files (e.g., CertificateBuilder.cs, X509Extensions.cs, X509SignatureFactory.cs) are refactored to drop NETSTANDARD2_0 support and use modern .NET APIs and conditional compilation.
- Test code across the codebase is updated to use default, strongly-typed Parse methods, collection expressions, and improved async/await patterns.
- Exception handling and assertions in tests are modernized, and test method naming is made consistent with Async suffixes.
- The project and build files are updated to clarify Roslynator analyzer usage and remove obsolete netstandard tags.
- General code and test cleanup includes improved null safety, type safety, and removal of deprecated or unused code.
* Use Central Package Management
* Add Directory.Packages.props to solution files
* remove sourcelink version from common.props
* remove old entry from signlist
* remove .net 6 target
remove conditional packages
remove debug flag from pubsub
* Remove net 6 from azp
* Update Nuget Packages
* Update missed pipeline
* Add net 8 App Target framework
* fix asn1 package reference
* remove more net 6 references from AZP
* move main pipeline to net 8
* install net 8 in runners
* install net 8 in CC yml pipeline
- Reduce memory allocations in JSON encoder by using stackalloc/ArrayPool
- Fix some new warnings in .NET9 code analyzers
- Fix fuzzing error in JsonDecoder
- do not use .NET9 libraries with .NET8 LTS builds #2931, #2940
- Bump langversion to 9 (max VS2019)
- Use official ASP.Net 2.3. libraries for .NET Framework (rel. Jan 15th)
- reduce EscapeString overhead in JSON encoder
- client monitored items: allocate queues only if needed
- replace SortedDictionary with Dictionary for perf reasons
- revert a change in padding and reduce a log level
Add the reconnect exception text to the log message, otherwise the exception is filtered out.
Turn off the trace logging in tests, as it causes timeout issues on some ci VMs
reduce callbacks if client reconnect and call AddItems
Fix BadNothingToDo when Loading dictionaries
Revert benchmark.net to v13 due to weird build dependency issues with 14.x
-reduce Xml/Json output of encoder tests to avoid out of memory exception (trx reduced from 600MB to 40MB)
-simplify a few NodeCache tests and disable a test case which produces a lot of exception logs
-default targets to net8.0 instead of net6.0
-fix benchmark cmd (required PlatformTarget)
-remove nunitxml.testlogger dependency from projects
Marc Schier