Redact password from query_options (#1334)

Redact password from query_options to avoid leaking
credentials in exceptions via #inspect. Minor refactor
to make RuboCop happy about client.rb complexity.

Closes #1049

.rubocop_todo.yml

@@ -45,7 +45,7 @@ Metrics/BlockNesting:
 # Offense count: 1
 # Configuration parameters: CountComments, CountAsOne.
 Metrics/ClassLength:
-  Max: 135
+  Max: 141
 
 # Offense count: 3
 # Configuration parameters: IgnoredMethods.

lib/mysql2/client.rb

@@ -71,12 +71,7 @@ def initialize(opts = {})
       # SSL verify is a connection flag rather than a mysql_ssl_set option
       flags |= SSL_VERIFY_SERVER_CERT if opts[:sslverify]
 
-      if %i[user pass hostname dbname db sock].any? { |k| @query_options.key?(k) }
-        warn "============= WARNING FROM mysql2 ============="
-        warn "The options :user, :pass, :hostname, :dbname, :db, and :sock are deprecated and will be removed at some point in the future."
-        warn "Instead, please use :username, :password, :host, :port, :database, :socket, :flags for the options."
-        warn "============= END WARNING FROM mysql2 ========="
-      end
+      check_and_clean_query_options
 
       user     = opts[:username] || opts[:user]
       pass     = opts[:password] || opts[:pass]
@@ -165,6 +160,21 @@ def info
       self.class.info
     end
 
+    private
+
+    def check_and_clean_query_options
+      if %i[user pass hostname dbname db sock].any? { |k| @query_options.key?(k) }
+        warn "============= WARNING FROM mysql2 ============="
+        warn "The options :user, :pass, :hostname, :dbname, :db, and :sock are deprecated and will be removed at some point in the future."
+        warn "Instead, please use :username, :password, :host, :port, :database, :socket, :flags for the options."
+        warn "============= END WARNING FROM mysql2 ========="
+      end
+
+      # avoid logging sensitive data via #inspect
+      @query_options.delete(:password)
+      @query_options.delete(:pass)
+    end
+
     class << self
       private
 

spec/mysql2/client_spec.rb

@@ -1195,4 +1195,22 @@ def run_gc
   it "should respond to #encoding" do
     expect(@client).to respond_to(:encoding)
   end
+
+  it "should not include the password in the output of #inspect" do
+    client_class = Class.new(Mysql2::Client) do
+      def connect(*args); end
+    end
+
+    client = client_class.new(password: "secretsecret")
+
+    expect(client.inspect).not_to include("password")
+    expect(client.inspect).not_to include("secretsecret")
+
+    expect do
+      client = client_class.new(pass: "secretsecret")
+    end.to output(/WARNING/).to_stderr
+
+    expect(client.inspect).not_to include("pass")
+    expect(client.inspect).not_to include("secretsecret")
+  end
 end

spec/mysql2/statement_spec.rb

@@ -320,7 +320,7 @@ def stmt_count
       result = @client.prepare("SELECT 1 UNION SELECT 2").execute(stream: true, cache_rows: false)
       expect do
         result.each {}
-        result.each {} # rubocop:disable Style/CombinableLoops
+        result.each {}
       end.to raise_exception(Mysql2::Error)
     end
   end