upd: refetch user keys on signature failure

Reference: https://github.com/misskey-dev/misskey/pull/12051

packages/backend/src/core/activitypub/ApDbResolverService.ts

@@ -12,7 +12,7 @@ import type { MiUserPublickey } from '@/models/UserPublickey.js';
 import { CacheService } from '@/core/CacheService.js';
 import type { MiNote } from '@/models/Note.js';
 import { bindThis } from '@/decorators.js';
-import { MiLocalUser, MiRemoteUser } from '@/models/User.js';
+import type { MiLocalUser, MiRemoteUser } from '@/models/User.js';
 import { getApId } from './type.js';
 import { ApPersonService } from './models/ApPersonService.js';
 import type { IObject } from './type.js';
@@ -164,6 +164,19 @@ export class ApDbResolverService implements OnApplicationShutdown {
 		};
 	}
 
+	/**
+	 * Sharkey User -> Refetched Key
+	 */
+	@bindThis
+	public async refetchPublicKeyForApId(user: MiRemoteUser): Promise<MiUserPublickey | null> {
+		await this.apPersonService.updatePerson(user.uri);
+		const key = await this.userPublickeysRepository.findOneBy({ userId: user.id });
+		if (key != null) {
+			await this.publicKeyByUserIdCache.set(user.id, key);
+		}
+		return key;
+	}
+
 	@bindThis
 	public dispose(): void {
 		this.publicKeyCache.dispose();

packages/backend/src/queue/processors/InboxProcessorService.ts

@@ -104,12 +104,24 @@ export class InboxProcessorService {
 		}
 
 		// HTTP-Signatureの検証
-		const httpSignatureValidated = httpSignature.verifySignature(signature, authUser.key.keyPem);
+		let httpSignatureValidated = httpSignature.verifySignature(signature, authUser.key.keyPem);
 
 		// また、signatureのsignerは、activity.actorと一致する必要がある
 		if (!httpSignatureValidated || authUser.user.uri !== activity.actor) {
+			let renewKeyFailed = false;
+			
+			if (!httpSignatureValidated) {
+				authUser.key = await this.apDbResolverService.refetchPublicKeyForApId(authUser.user);
+
+				if (authUser.key != null) {
+					httpSignatureValidated = httpSignature.verifySignature(signature, authUser.key.keyPem);
+				} else {
+					renewKeyFailed = true;
+				}
+			}
+
 			// 一致しなくても、でもLD-Signatureがありそうならそっちも見る
-			if (activity.signature) {
+			if (activity.signature && renewKeyFailed) {
 				if (activity.signature.type !== 'RsaSignature2017') {
 					throw new Bull.UnrecoverableError(`skip: unsupported LD-signature type ${activity.signature.type}`);
 				}