fix(migrate): oauth account:* spec, p256 support

Lewis: May this revision serve well! <lu5a@proton.me>

frontend/public/oauth-client-metadata.json

@@ -8,7 +8,7 @@
   ],
   "grant_types": ["authorization_code", "refresh_token"],
   "response_types": ["code"],
-  "scope": "atproto transition:generic repo:* blob:*/* rpc:* rpc:com.atproto.server.createAccount?aud=* account:*?action=manage identity:*",
+  "scope": "atproto transition:generic repo:* blob:*/* rpc:* rpc:com.atproto.server.createAccount?aud=* account:*?action=manage account:repo?action=manage identity:*",
   "token_endpoint_auth_method": "none",
   "application_type": "web",
   "dpop_bound_access_tokens": true

frontend/src/lib/migration/offline-flow.svelte.ts

@@ -209,11 +209,15 @@ export function createOfflineInboundMigrationFlow() {
     }
 
     try {
-      userRotationKeypair = await plcOps.getKeyPair(state.rotationKey.trim());
       const { lastOperation } = await plcOps.getLastPlcOpFromPlc(state.userDid);
       const currentRotationKeys = lastOperation.rotationKeys || [];
 
-      if (!currentRotationKeys.includes(userRotationKeypair.didPublicKey)) {
+      userRotationKeypair = await plcOps.getMatchingKeyPair(
+        state.rotationKey.trim(),
+        currentRotationKeys,
+      );
+
+      if (!userRotationKeypair) {
         state.rotationKeyDidKey = "";
         return false;
       }

frontend/src/lib/migration/plc-ops.ts

@@ -248,6 +248,33 @@ export class PlcOps {
     };
   }
 
+  async getMatchingKeyPair(
+    privateKeyString: string,
+    acceptableDidKeys: readonly string[],
+  ): Promise<KeypairInfo | null> {
+    const curves: readonly KeyCurve[] = ["secp256k1", "p256"];
+    const results = await Promise.allSettled(
+      curves.map((curve) => this.getKeyPair(privateKeyString, curve)),
+    );
+    const candidates = results
+      .filter(
+        (r): r is PromiseFulfilledResult<KeypairInfo> =>
+          r.status === "fulfilled",
+      )
+      .map((r) => r.value);
+    if (candidates.length === 0) {
+      const rejection = results.find(
+        (r): r is PromiseRejectedResult => r.status === "rejected",
+      );
+      throw rejection?.reason ?? new Error("Unrecognized key format");
+    }
+    return (
+      candidates.find((info) =>
+        acceptableDidKeys.includes(info.didPublicKey)
+      ) ?? null
+    );
+  }
+
   async signAndPublishNewOp(
     did: string,
     signingRotationKey: PrivateKey,

frontend/src/tests/migration/plc-ops.test.ts

@@ -144,6 +144,45 @@ describe("migration/plc-ops", () => {
     });
   });
 
+  describe("getMatchingKeyPair", () => {
+    it("resolves a P-256 key supplied as hex against its did:key", async () => {
+      const keypair = await P256PrivateKeyExportable.createKeypair();
+      const rawHex = await keypair.exportPrivateKey("rawHex");
+      const did = await keypair.exportPublicKey("did");
+
+      const result = await plcOps.getMatchingKeyPair(rawHex, [did]);
+
+      expect(result?.didPublicKey).toBe(did);
+    });
+
+    it("resolves a secp256k1 key supplied as hex against its did:key", async () => {
+      const keypair = await Secp256k1PrivateKeyExportable.createKeypair();
+      const rawHex = await keypair.exportPrivateKey("rawHex");
+      const did = await keypair.exportPublicKey("did");
+
+      const result = await plcOps.getMatchingKeyPair(rawHex, [did]);
+
+      expect(result?.didPublicKey).toBe(did);
+    });
+
+    it("returns null when no curve matches the accepted keys", async () => {
+      const keypair = await P256PrivateKeyExportable.createKeypair();
+      const rawHex = await keypair.exportPrivateKey("rawHex");
+
+      const result = await plcOps.getMatchingKeyPair(rawHex, [
+        "did:key:zQ3shqPwo8CSE8zNXEyEpN4ASEBCCNeUFQq8Lrw3zkAJYB7SB",
+      ]);
+
+      expect(result).toBeNull();
+    });
+
+    it("throws on unparseable input", async () => {
+      await expect(
+        plcOps.getMatchingKeyPair("not-a-valid-key", []),
+      ).rejects.toThrow();
+    });
+  });
+
   describe("getKeyPair - JWK format", () => {
     it("imports secp256k1 JWK with d parameter", async () => {
       const keypair = await Secp256k1PrivateKeyExportable.createKeypair();