Files
Marc Schier ae34b02938 Fuzzing coverage expansion (Full Encoders / Certificates / Network) (#3867)
# 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.
2026-06-12 10:15:28 +02:00

361 lines
15 KiB
C#

/* ========================================================================
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*
* OPC Foundation MIT License 1.00
*
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
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* ======================================================================*/
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace Opc.Ua.Fuzzing
{
public static partial class Testcases
{
public enum TestCaseEncoders
{
Binary = 0,
Json = 1,
Xml = 2
}
/// <summary>
/// Run the encoder test cases
/// </summary>
/// <param name="workPath"></param>
/// <param name="telemetry">The telemetry context to use to create obvservability instruments</param>
public static void Run(string workPath, ITelemetryContext telemetry)
{
// Create the Testcases for the binary decoder.
FuzzableCode.MessageContext = ServiceMessageContext.Create(telemetry);
string pathSuffix = GetTestcaseEncoderSuffix(TestCaseEncoders.Binary);
string pathTarget = workPath + pathSuffix + Path.DirectorySeparatorChar;
Directory.CreateDirectory(pathTarget);
foreach (MessageEncoder messageEncoder in GetMessageEncoders())
{
byte[] message;
using (var encoder = new BinaryEncoder(FuzzableCode.MessageContext))
{
messageEncoder(encoder);
message = encoder.CloseAndReturnBuffer();
}
// Test the fuzz targets with the message.
FuzzableCode.LibfuzzBinaryDecoder(message);
FuzzableCode.LibfuzzBinaryEncoder(message);
using (var stream = new MemoryStream(message))
{
FuzzableCode.AflfuzzBinaryDecoder(stream);
}
using (var stream = new MemoryStream(message))
{
FuzzableCode.AflfuzzBinaryEncoder(stream);
}
using (var stream = new MemoryStream(message))
{
FuzzableCode.FuzzBinaryDecoderCore(stream, true);
}
string fileName = Path.Combine(
pathTarget,
$"{messageEncoder.Method.Name}.bin".ToLowerInvariant());
File.WriteAllBytes(fileName, message);
}
// Create the Testcases for the json decoder.
pathSuffix = GetTestcaseEncoderSuffix(TestCaseEncoders.Json);
pathTarget = workPath + pathSuffix + Path.DirectorySeparatorChar;
Directory.CreateDirectory(pathTarget);
foreach (MessageEncoder messageEncoder in GetMessageEncoders())
{
byte[] message;
using (var memoryStream = new MemoryStream(0x1000))
using (var encoder = new JsonEncoder(memoryStream, FuzzableCode.MessageContext))
{
messageEncoder(encoder);
encoder.Close();
message = memoryStream.ToArray();
}
// Test the fuzz targets with the message.
FuzzableCode.LibfuzzJsonDecoder(message);
FuzzableCode.LibfuzzJsonEncoder(message);
string json = Encoding.UTF8.GetString(message);
FuzzableCode.AflfuzzJsonDecoder(json);
FuzzableCode.AflfuzzJsonEncoder(json);
FuzzableCode.FuzzJsonDecoderCore(json);
string fileName = Path.Combine(
pathTarget,
$"{messageEncoder.Method.Name}.json".ToLowerInvariant());
File.WriteAllBytes(fileName, message);
}
// Create the Testcases for the xml decoder.
pathSuffix = GetTestcaseEncoderSuffix(TestCaseEncoders.Xml);
pathTarget = workPath + pathSuffix + Path.DirectorySeparatorChar;
Directory.CreateDirectory(pathTarget);
foreach (MessageEncoder messageEncoder in GetMessageEncoders())
{
string xml;
using (var encoder = new XmlEncoder(FuzzableCode.MessageContext))
{
encoder.SetMappingTables(
FuzzableCode.MessageContext.NamespaceUris,
FuzzableCode.MessageContext.ServerUris);
messageEncoder(encoder);
xml = encoder.CloseAndReturnText();
}
// Test the fuzz targets with the message.
byte[] message = Encoding.UTF8.GetBytes(xml);
using (var stream = new MemoryStream(message))
{
FuzzableCode.AflfuzzXmlDecoder(stream);
}
using (var stream = new MemoryStream(message))
{
FuzzableCode.AflfuzzXmlEncoder(stream);
}
using (var stream = new MemoryStream(message))
{
FuzzableCode.FuzzXmlDecoderCore(stream);
}
FuzzableCode.LibfuzzXmlDecoder(message);
FuzzableCode.LibfuzzXmlEncoder(message);
string fileName = Path.Combine(
pathTarget,
$"{messageEncoder.Method.Name}.xml".ToLowerInvariant());
File.WriteAllBytes(fileName, Encoding.UTF8.GetBytes(xml));
}
WriteBuiltInTypeTestcases(workPath);
WriteParserTestcases(workPath);
}
private static string GetTestcaseEncoderSuffix(TestCaseEncoders encoder)
{
return "." + encoder;
}
private delegate void BuiltInEncoder(IEncoder encoder);
private static IEnumerable<MessageEncoder> GetMessageEncoders()
{
foreach (MessageEncoder messageEncoder in MessageEncoders)
{
yield return messageEncoder;
}
yield return BrowseRequest;
yield return WriteRequest;
}
private static void BrowseRequest(IEncoder encoder)
{
var browseRequest = new BrowseRequest
{
RequestHeader = CreateRequestHeader(),
RequestedMaxReferencesPerNode = 10,
NodesToBrowse =
[
new BrowseDescription
{
NodeId = ObjectIds.ObjectsFolder,
BrowseDirection = BrowseDirection.Forward,
ReferenceTypeId = ReferenceTypeIds.HierarchicalReferences,
IncludeSubtypes = true,
NodeClassMask = (uint)(NodeClass.Object | NodeClass.Variable),
ResultMask = (uint)BrowseResultMask.All
}
]
};
encoder.EncodeMessage(browseRequest);
}
private static void WriteRequest(IEncoder encoder)
{
var writeRequest = new WriteRequest
{
RequestHeader = CreateRequestHeader(),
NodesToWrite =
[
new WriteValue
{
NodeId = new NodeId(1000, 2),
AttributeId = Attributes.Value,
Value = new DataValue(
Variant.From(new LocalizedText("en-US", "Hello World")),
StatusCodes.Good,
DateTimeUtc.Now)
}
]
};
encoder.EncodeMessage(writeRequest);
}
private static RequestHeader CreateRequestHeader()
{
return new RequestHeader
{
Timestamp = DateTime.UtcNow,
RequestHandle = 42,
AdditionalHeader = new ExtensionObject(new ReadValueId
{
NodeId = new NodeId(2253),
AttributeId = Attributes.Value
})
};
}
private static void WriteBuiltInTypeTestcases(string workPath)
{
string builtInPath = workPath + ".BuiltInTypes" + Path.DirectorySeparatorChar;
Directory.CreateDirectory(builtInPath);
foreach ((string name, BuiltInEncoder builtInEncoder) in GetBuiltInEncoders())
{
string binaryPath = Path.Combine(builtInPath, "Binary");
Directory.CreateDirectory(binaryPath);
using (var encoder = new BinaryEncoder(FuzzableCode.MessageContext))
{
builtInEncoder(encoder);
File.WriteAllBytes(
Path.Combine(binaryPath, name + ".bin"),
encoder.CloseAndReturnBuffer() ?? []);
}
string jsonPath = Path.Combine(builtInPath, "Json");
Directory.CreateDirectory(jsonPath);
using (var memoryStream = new MemoryStream(0x1000))
using (var encoder = new JsonEncoder(memoryStream, FuzzableCode.MessageContext))
{
builtInEncoder(encoder);
encoder.Close();
File.WriteAllBytes(Path.Combine(jsonPath, name + ".json"), memoryStream.ToArray());
}
string xmlPath = Path.Combine(builtInPath, "Xml");
Directory.CreateDirectory(xmlPath);
File.WriteAllText(
Path.Combine(xmlPath, name + ".xml"),
GetXmlBuiltInSeed(name),
Encoding.UTF8);
}
}
private static IEnumerable<(string Name, BuiltInEncoder Encoder)> GetBuiltInEncoders()
{
yield return ("nodeid", encoder => encoder.WriteNodeId("Value", new NodeId(1000, 2)));
yield return ("expandednodeid", encoder => encoder.WriteExpandedNodeId(
"Value",
new ExpandedNodeId(new NodeId(1000, 2), "urn:example:namespace", 1)));
yield return ("variant", encoder => encoder.WriteVariant(
"Value",
Variant.From(new LocalizedText("en-US", "Hello World"))));
yield return ("extensionobject", encoder => encoder.WriteExtensionObject(
"Value",
new ExtensionObject(new ReadValueId
{
NodeId = new NodeId(2253),
AttributeId = Attributes.Value
})));
yield return ("datavalue", encoder => encoder.WriteDataValue(
"Value",
new DataValue(
Variant.From(new QualifiedName("Temperature", 2)),
StatusCodes.Good,
DateTimeUtc.Now)));
yield return ("diagnosticinfo", encoder => encoder.WriteDiagnosticInfo(
"Value",
new DiagnosticInfo
{
AdditionalInfo = "seed diagnostic",
InnerStatusCode = StatusCodes.BadNodeIdUnknown,
InnerDiagnosticInfo = new DiagnosticInfo
{
AdditionalInfo = "inner diagnostic",
InnerStatusCode = StatusCodes.BadDecodingError
}
}));
yield return ("qualifiedname", encoder => encoder.WriteQualifiedName(
"Value",
new QualifiedName("Temperature", 2)));
yield return ("localizedtext", encoder => encoder.WriteLocalizedText(
"Value",
new LocalizedText("en-US", "Hello World")));
}
private static string GetXmlBuiltInSeed(string name)
{
const string ns = " xmlns=\"http://opcfoundation.org/UA/2008/02/Types.xsd\"";
return name switch
{
"nodeid" => $"<Value{ns}><Identifier>ns=2;i=1000</Identifier></Value>",
"expandednodeid" => $"<Value{ns}><Identifier>svr=1;nsu=urn:example:namespace;i=1000" +
"</Identifier></Value>",
"variant" => $"<Value{ns}><Value><String>Hello World</String></Value></Value>",
"extensionobject" => $"<Value{ns}><TypeId><Identifier>i=628</Identifier></TypeId></Value>",
"datavalue" => $"<Value{ns}><Value><Value><String>Hello World</String></Value></Value></Value>",
"diagnosticinfo" => $"<Value{ns}><AdditionalInfo>seed diagnostic</AdditionalInfo></Value>",
"qualifiedname" => $"<Value{ns}><NamespaceIndex>2</NamespaceIndex><Name>Temperature</Name></Value>",
"localizedtext" => $"<Value{ns}><Locale>en-US</Locale><Text>Hello World</Text></Value>",
_ => $"<Value{ns} />"
};
}
private static void WriteParserTestcases(string workPath)
{
string parserPath = workPath + ".Parsers" + Path.DirectorySeparatorChar;
Directory.CreateDirectory(parserPath);
foreach ((string name, string text) in GetParserSeeds())
{
File.WriteAllText(Path.Combine(parserPath, name + ".txt"), text, Encoding.UTF8);
}
}
private static IEnumerable<(string Name, string Text)> GetParserSeeds()
{
yield return ("nodeid_numeric", "i=85");
yield return ("nodeid_string", "ns=2;s=Demo.Node");
yield return ("nodeid_guid", "ns=2;g=00000000-0000-0000-0000-000000000001");
yield return ("expandednodeid_uri", "svr=1;nsu=http://opcfoundation.org/UA/;i=85");
yield return ("expandednodeid_string", "nsu=urn:example:namespace;s=Demo");
yield return ("relativepath_child", "/2:Block/2:Parameter");
yield return ("relativepath_property", ".2:EngineeringUnits");
yield return ("qualifiedname", "2:Temperature");
yield return ("numericrange_single", "0");
yield return ("numericrange_matrix", "0:10,1:2");
yield return ("uuid", "00000000-0000-0000-0000-000000000001");
}
}
}