Fix ResolveAccountService accepting mismatching acct: URI (#15368)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/services/resolve_account_service.rb

@@ -46,7 +46,7 @@ class ResolveAccountService < BaseService
     # Now it is certain, it is definitely a remote account, and it
     # either needs to be created, or updated from fresh data
 
-    process_account!
+    fetch_account!
   rescue Webfinger::Error, WebfingerRedirectError, Oj::ParseError => e
     Rails.logger.debug "Webfinger query for #{@uri} failed: #{e}"
     nil
@@ -99,16 +99,12 @@ class ResolveAccountService < BaseService
     acct.gsub(/\Aacct:/, '').split('@')
   end
 
-  def process_account!
+  def fetch_account!
     return unless activitypub_ready?
 
     RedisLock.acquire(lock_options) do |lock|
       if lock.acquired?
-        @account = Account.find_remote(@username, @domain)
+        @account = ActivityPub::FetchRemoteAccountService.new.call(actor_url)
-
-        next if actor_json.nil?
-
-        @account = ActivityPub::ProcessAccountService.new.call(@username, @domain, actor_json)
       else
         raise Mastodon::RaceConditionError
       end

spec/services/resolve_account_service_spec.rb

@@ -35,7 +35,22 @@ RSpec.describe ResolveAccountService, type: :service do
 
   context 'with a legitimate webfinger redirection' do
     before do
-      webfinger = { subject: 'acct:foo@ap.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo' }] }
+      webfinger = { subject: 'acct:foo@ap.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo', type: 'application/activity+json' }] }
+      stub_request(:get, 'https://redirected.example.com/.well-known/webfinger?resource=acct:Foo@redirected.example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
+    end
+
+    it 'returns new remote account' do
+      account = subject.call('Foo@redirected.example.com')
+
+      expect(account.activitypub?).to eq true
+      expect(account.acct).to eq 'foo@ap.example.com'
+      expect(account.inbox_url).to eq 'https://ap.example.com/users/foo/inbox'
+    end
+  end
+
+  context 'with a misconfigured redirection' do
+    before do
+      webfinger = { subject: 'acct:Foo@redirected.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo', type: 'application/activity+json' }] }
       stub_request(:get, 'https://redirected.example.com/.well-known/webfinger?resource=acct:Foo@redirected.example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
     end
 
@@ -50,9 +65,9 @@ RSpec.describe ResolveAccountService, type: :service do
 
   context 'with too many webfinger redirections' do
     before do
-      webfinger = { subject: 'acct:foo@evil.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo' }] }
+      webfinger = { subject: 'acct:foo@evil.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo', type: 'application/activity+json' }] }
       stub_request(:get, 'https://redirected.example.com/.well-known/webfinger?resource=acct:Foo@redirected.example.com').to_return(body: Oj.dump(webfinger), headers: { 'Content-Type': 'application/jrd+json' })
-      webfinger2 = { subject: 'acct:foo@ap.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo' }] }
+      webfinger2 = { subject: 'acct:foo@ap.example.com', links: [{ rel: 'self', href: 'https://ap.example.com/users/foo', type: 'application/activity+json' }] }
       stub_request(:get, 'https://evil.example.com/.well-known/webfinger?resource=acct:foo@evil.example.com').to_return(body: Oj.dump(webfinger2), headers: { 'Content-Type': 'application/jrd+json' })
     end