2 files changed, 41 insertions, 6 deletions
diff --git a/app/controllers/concerns/signature_verification.rb b/app/controllers/concerns/signature_verification.rb
index abe845d93..aeb8da879 100644
--- a/app/controllers/concerns/signature_verification.rb
+++ b/app/controllers/concerns/signature_verification.rb
@@ -31,7 +31,7 @@ module SignatureVerification
       return
     end
 
-    account = ResolveRemoteAccountService.new.call(signature_params['keyId'].gsub(/\Aacct:/, ''))
+    account = account_from_key_id(signature_params['keyId'])
 
     if account.nil?
       @signed_request_account = nil
@@ -49,6 +49,10 @@ module SignatureVerification
     end
   end
 
+  def request_body
+    @request_body ||= request.raw_post
+  end
+
   private
 
   def build_signed_string(signed_headers)
@@ -57,6 +61,8 @@ module SignatureVerification
     signed_headers.split(' ').map do |signed_header|
       if signed_header == Request::REQUEST_TARGET
         "#{Request::REQUEST_TARGET}: #{request.method.downcase} #{request.path}"
+      elsif signed_header == 'digest'
+        "digest: #{body_digest}"
       else
         "#{signed_header}: #{request.headers[to_header_name(signed_header)]}"
       end
@@ -73,6 +79,10 @@ module SignatureVerification
     (Time.now.utc - time_sent).abs <= 30
   end
 
+  def body_digest
+    "SHA-256=#{Digest::SHA256.base64digest(request_body)}"
+  end
+
   def to_header_name(name)
     name.split(/-/).map(&:capitalize).join('-')
   end
@@ -81,7 +91,14 @@ module SignatureVerification
     signature_params['keyId'].blank? ||
       signature_params['signature'].blank? ||
       signature_params['algorithm'].blank? ||
-      signature_params['algorithm'] != 'rsa-sha256' ||
-      !signature_params['keyId'].start_with?('acct:')
+      signature_params['algorithm'] != 'rsa-sha256'
+  end
+
+  def account_from_key_id(key_id)
+    if key_id.start_with?('acct:')
+      ResolveRemoteAccountService.new.call(key_id.gsub(/\Aacct:/, ''))
+    elsif !ActivityPub::TagManager.instance.local_uri?(key_id)
+      ActivityPub::FetchRemoteAccountService.new.call(key_id)
+    end
   end
 end
diff --git a/app/lib/request.rb b/app/lib/request.rb
index e73c5ac20..c01e07925 100644
--- a/app/lib/request.rb
+++ b/app/lib/request.rb
@@ -12,15 +12,21 @@ class Request
     @headers = {}
 
     set_common_headers!
+    set_digest! if options.key?(:body)
   end
 
-  def on_behalf_of(account)
+  def on_behalf_of(account, key_id_format = :acct)
     raise ArgumentError unless account.local?
-    @account = account
+
+    @account       = account
+    @key_id_format = key_id_format
+
+    self
   end
 
   def add_headers(new_headers)
     @headers.merge!(new_headers)
+    self
   end
 
   def perform
@@ -40,8 +46,11 @@ class Request
     @headers['Date']         = Time.now.utc.httpdate
   end
 
+  def set_digest!
+    @headers['Digest'] = "SHA-256=#{Digest::SHA256.base64digest(@options[:body])}"
+  end
+
   def signature
-    key_id    = @account.to_webfinger_s
     algorithm = 'rsa-sha256'
     signature = Base64.strict_encode64(@account.keypair.sign(OpenSSL::Digest::SHA256.new, signed_string))
 
@@ -60,6 +69,15 @@ class Request
     @user_agent ||= "#{HTTP::Request::USER_AGENT} (Mastodon/#{Mastodon::Version}; +#{root_url})"
   end
 
+  def key_id
+    case @key_id_format
+    when :acct
+      @account.to_webfinger_s
+    when :uri
+      [ActivityPub::TagManager.instance.uri_for(@account), '#main-key'].join
+    end
+  end
+
   def timeout
     { write: 10, connect: 10, read: 10 }
   end