Sync credentials as a vault item type, and bind one to a host

Closes the largest remaining M1 gap in the data layer: a username and password can live in the vault, sync between machines, and be named by a host as how it authenticates. What is not here is the interface for creating one — see the end of this message. The third item type, and the first one that cost almost nothing to add. Server: a VaultCredential row, an EF configuration, a migration, and a CredentialKind. Client: a secret, a codec, a merge, a cipher, a kind, a repository facade and a session property. No new reconciliation logic, no change to the sync engine, no client cache migration. That was the whole point of the item-kind seam, and this is the evidence it holds. The narrowest type of the three on plaintext, and not for symmetry. A host has a deliberate concession — the relay needs an address it can resolve. A key has a fingerprint, public by nature, which this client still declines to send. A password has no part that is safe to expose: not its length, not a hash, not a hint. So CredentialKind refuses every plaintext field there is, hydrates none, and the table has no column to put one in. HostSecret.CredentialId is the password counterpart of SshKeyId, and the two are mutually exclusive. SSH itself would happily try a key and fall back to a password, but a host naming both leaves "how does this authenticate?" without a single answer — the interface, the connect path and the user would each be free to guess differently. TryValidate refuses it. One consequence was not anticipated: "a full host" stops being a coherent idea, which is what broke AFullHost_RoundTrips and is now written into that test. The schema version became a ladder rather than a maximum: credential-bound is 3, key-bound is 2, neither is still 1. Adding credentials therefore does not drag every key-bound host in every vault onto a version that clients understanding keys perfectly well would refuse to edit. A test pins exactly that, because it is the property the whole content-dependent-version rule exists to provide, and the obvious implementation would quietly lose it. Two tests had become false and said so: - Push_AnUnsupportedEntityType_IsInvalidNotAFailedBatch used Credential as its example of a type this server does not implement. It now asks the server's own registry what is still missing, so it cannot go stale again, and skips with a reason if that set ever empties. - ThePullFilterNamesEveryTypeThisBuildSynchronises pinned the exact list, which is what it is for. Also fixes ten nullable warnings — eight in SyncEndpointTests, two in a test file added earlier today. Neither set was introduced here; both were invisible until an unrelated change forced their project to recompile, which means the zero-warning claims made earlier in this work only ever covered what happened to be rebuilt. 777 tests green. Zero warnings, dotnet format clean. Not done, and deliberately: the credential interface. The vault column is 340 pixels wide and already holds two lists and two editors, kept from clipping its own buttons at the window's minimum height only by the one-editor-at-a-time rule added earlier today. A third list and a third editor would recreate that defect rather than avoid it, so the column needs a shape decision first. Credentials sync; they cannot yet be created in the interface.
2026-07-29 21:09:08 +02:00
parent 70b3290a77
commit e24012b039
27 changed files with 2812 additions and 23 deletions
@@ -68,7 +68,7 @@ internal interface IItemKind
 internal static class ItemKinds
 {
    private static readonly Dictionary<SyncEntityType, IItemKind> Supported =
-        new[] { (IItemKind)new HostKind(), new SshKeyKind() }
+        new[] { (IItemKind)new HostKind(), new SshKeyKind(), new CredentialKind() }
            .ToDictionary(kind => kind.WireType);

    /// <summary>The kind for a wire type, or null when this server does not synchronise it yet.</summary>
@@ -292,3 +292,98 @@ internal sealed class SshKeyKind : IItemKind
            ? new SyncPlaintextFields(PublicKeyFingerprint: fingerprint)
            : null;
 }
+
+/// <summary>Credentials: an envelope and nothing else.</summary>
+/// <remarks>
+/// The strictest of the three kinds about plaintext, and the reason is not symmetry. A key at least has a
+/// fingerprint that is public by nature; a password has no part that is safe to expose, so this kind accepts
+/// no plaintext fields at all and hydrates none.
+/// </remarks>
+internal sealed class CredentialKind : IItemKind
+{
+    /// <inheritdoc />
+    public SyncEntityType WireType => SyncEntityType.Credential;
+
+    /// <inheritdoc />
+    public ChangeEntityType ChangeType => ChangeEntityType.Credential;
+
+    /// <inheritdoc />
+    public async Task<IVaultItem?> FindAsync(
+        DodoDbContext database,
+        Guid id,
+        CancellationToken cancellationToken) =>
+        await database.Credentials.SingleOrDefaultAsync(c => c.Id == id, cancellationToken)
+            .ConfigureAwait(false);
+
+    /// <inheritdoc />
+    public async Task<Dictionary<Guid, IVaultItem>> LoadAsync(
+        DodoDbContext database,
+        Guid vaultId,
+        Guid[] ids,
+        CancellationToken cancellationToken)
+    {
+        var rows = await database.Credentials
+            .Where(c => c.VaultId == vaultId && ids.Contains(c.Id))
+            .ToListAsync(cancellationToken)
+            .ConfigureAwait(false);
+
+        return rows.ToDictionary(row => row.Id, row => (IVaultItem)row);
+    }
+
+    /// <inheritdoc />
+    public IVaultItem Add(DodoDbContext database, Guid id, Guid vaultId)
+    {
+        var credential = new VaultCredential { Id = id, VaultId = vaultId };
+
+        database.Credentials.Add(credential);
+
+        return credential;
+    }
+
+    /// <summary>
+    /// Refuses every plaintext field there is.
+    /// </summary>
+    /// <remarks>
+    /// Refused with a reason rather than silently dropped, so a client that believes it is storing something
+    /// finds out now rather than when the field turns out to be missing.
+    /// </remarks>
+    /// <inheritdoc />
+    public bool ValidateFields(SyncPlaintextFields fields, out string error)
+    {
+        ArgumentNullException.ThrowIfNull(fields);
+
+        error = string.Empty;
+
+        if (fields.RelayEnabled || fields.Hostname is not null || fields.Port is not null)
+        {
+            error = "A credential has no relay target; relay fields may only be set on a host.";
+            return false;
+        }
+
+        if (fields.PublicKeyFingerprint is not null)
+        {
+            error = "A credential has no public key.";
+            return false;
+        }
+
+        return true;
+    }
+
+    /// <remarks>Nothing to copy: this type has no plaintext columns to copy anything into.</remarks>
+    /// <inheritdoc />
+    public void ApplyFields(IVaultItem item, SyncPlaintextFields fields)
+    {
+    }
+
+    /// <inheritdoc />
+    public void ClearFieldsOnDelete(IVaultItem item)
+    {
+    }
+
+    /// <remarks>
+    /// Always null, which is a stronger statement than an empty record: this type has no plaintext columns,
+    /// so there is nothing a pull could hydrate even in principle.
+    /// </remarks>
+    /// <inheritdoc />
+    public SyncPlaintextFields? Hydrate(IVaultItem item) => null;
+}