Joseph Doherty
dbb580b2c8
Adds `MxAsbClient.Probe --dump-signed-xml` flag that builds five ConnectedRequest shapes (AuthenticateMe, Disconnect, KeepAlive, RegisterItemsRequest, UnregisterItemsRequest) with deterministic field values and prints `AsbSerialization.ToXml(...)` output. The output is exactly what `AsbSystemAuthenticator.Sign` HMACs (`AsbSystemAuthenticator.cs:79`), so the Rust port's canonical-XML emitter must produce byte-identical bytes for HMAC parity. Captured fixtures land under `rust/crates/mxaccess-asb/tests/fixtures/signed-xml/`: - `authenticate-me.xml` — 1000 bytes - `disconnect.xml` — 980 bytes - `keep-alive.xml` — 705 bytes - `register-items.xml` — 1068 bytes - `unregister-items.xml` — 1072 bytes Plus a `README.md` documenting 10 inferred XmlSerializer rules (element name = class name not WrapperName, field order = declaration order not [MessageBodyMember.Order], `[XmlType.Namespace]` on field type causes per-child xmlns redeclaration on the children not the wrapper, `*Specified` pattern controls Xxx emission, CRLF + 2-space indent + utf-16 declaration but UTF-8 bytes fed to HMAC). `.gitattributes` marks the XML fixtures as binary (`*.xml -text`) so neither `core.autocrlf` nor `text` filters can rewrite the byte content — CRLF is part of the canonical form and must survive round-trip through Git untouched. `MxAsbClient.csproj` gains `<InternalsVisibleTo Include="MxAsbClient .Probe" />` so the probe can reach the internal `AsbSerialization` helper without making it public. Workspace: 702 tests pass (no Rust changes — fixtures only). F28 follow-up updated with the captured fixtures + the inferred rules. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
100 lines
4.0 KiB
Markdown
100 lines
4.0 KiB
Markdown
# Signed-request XML fixtures
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Canonical `XmlSerializer` output for every `ConnectedRequest` shape that
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the .NET reference HMACs in `AsbSystemAuthenticator.Sign`
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(`src/MxAsbClient/AsbSystemAuthenticator.cs:79`). The Rust port's
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canonical-XML emitter (F28) must produce these exact UTF-8 bytes for
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the HMAC to match the server's recomputation.
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## Capture procedure
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```powershell
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dotnet run --project src\MxAsbClient.Probe -c Release -- --dump-signed-xml > capture.txt
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```
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The probe's `--dump-signed-xml` flag (added 2026-05-05) builds each
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shape with deterministic field values and prints the output of
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`AsbSerialization.ToXml(...)` (`src/MxAsbClient/AsbSerialization.cs:12`).
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## Pinned values
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All shapes use the same `ConnectionValidator`:
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- `ConnectionId = 8cba964a-74c1-ef74-f6aa-761b3540191b`
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- `MessageNumber = 42`
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- `MessageAuthenticationCode = AAECAwQFBgcICQoLDA0ODw==` (base64 of bytes 0..15)
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- `SignatureInitializationVector = EBESExQVFhcYGRobHB0eHw==` (base64 of bytes 16..31)
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`AuthenticateMe` and `Disconnect` use `AuthenticationData` with:
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- `Data = "deterministic-ciphertext-bytes"` (base64-encoded)
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- `InitializationVector = "0123456789abcdef"` (base64-encoded)
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`RegisterItemsRequest` uses one `ItemIdentity` with
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`Type = Name (0)`, `ReferenceType = Absolute (1)`,
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`Name = "TestChildObject.TestInt"`, `ContextName = ""`.
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`UnregisterItemsRequest` uses one `ItemIdentity` with
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`Type = Id (1)`, `ReferenceType = Absolute (1)`, `Name = null`,
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`ContextName = null`, `Id = 0xCAFEBABEDEADBEEF (14627333968688430831)`,
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`IdSpecified = true`.
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## Observed serialiser behaviour
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These rules were inferred from the captured output and from the .NET
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source for `XmlSerializer`:
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1. **Element name = class name**, NOT `[MessageContract.WrapperName]`.
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`XmlSerializer` does not honour WCF's MessageContract attributes.
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2. **Top-element xmlns ordering** (after `<?xml ... ?>`):
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`xmlns:xsi`, then `xmlns:xsd`, then default `xmlns`.
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The `AsbSerialization.ToXml` post-process (`AsbSerialization.cs:36-47`)
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reparses with `XDocument.Load` and reorders to put `xsi` before
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`xsd` — `XmlSerializer`'s native order is the opposite.
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3. **Field order = C# declaration order** (with inherited fields
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first), NOT `[MessageBodyMember.Order]`.
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4. **`[XmlType(Namespace = ...)]` on a field's type** triggers an
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`xmlns="..."` redeclaration on EACH child element of that type's
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instance, NOT on the wrapper element itself. e.g. inside
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`<ConnectionValidator>`, every direct child gets
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`xmlns="http://asb.contracts.data/20111111"`.
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5. **`byte[]` fields** serialise as base64 text content.
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**`Guid`** as canonical lowercase D-format (`8cba964a-74c1-...`).
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**`ulong`** as decimal.
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**`bool`** as `"true"` / `"false"`.
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6. **Null reference-type fields** with `[XmlElement(IsNullable = true)]`
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produce `<Name xsi:nil="true" xmlns="..." />`.
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Empty string fields produce a self-closing `<ContextName xmlns="..." />`.
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7. **`*Specified` pattern**: a public bool field named `XxxSpecified` =
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`true` causes XmlSerializer to emit the corresponding `<Xxx>`
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element. `IdSpecified = false` (default) → `<Id>` omitted.
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`IdSpecified = true` → `<Id>` emitted with the int value.
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The `*Specified` field itself is `[XmlIgnore]` and never emitted.
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8. **Self-closing elements** use ` />` (space before `/>`).
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9. **Indentation**: 2 spaces, `\r\n` line endings, no trailing
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newline after the closing tag.
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10. **XML declaration**: `<?xml version="1.0" encoding="utf-16"?>` —
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note `utf-16` even though `AsbSystemAuthenticator.Sign` HMACs
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`Encoding.UTF8.GetBytes(...)` of this string. The declaration is
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a static .NET StringWriter default; the actual byte encoding fed
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to HMAC is UTF-8.
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## Files
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- `authenticate-me.xml` — `AuthenticateMe`
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- `disconnect.xml` — `Disconnect`
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- `keep-alive.xml` — `KeepAlive`
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- `register-items.xml` — `RegisterItemsRequest`
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- `unregister-items.xml` — `UnregisterItemsRequest`
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Each file is the verbatim UTF-8 representation of `request.ToXml()`,
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with literal `\r\n` line endings preserved. Treat as binary (don't
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let your editor reformat).
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