Merge pull request github#13066 from maikypedia/maikypedia/sqli-sink-2

Ruby: Add Sequel as SQL Injection Sink

Author: alexrford

ruby/ql/lib/change-notes/2023-05-07-sequel.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Support for the `sequel` gem has been added. Method calls that execute queries against a database that may be vulnerable to injection attacks will now be recognized.

ruby/ql/lib/codeql/ruby/Frameworks.qll

@@ -33,3 +33,4 @@ private import codeql.ruby.frameworks.Sinatra
 private import codeql.ruby.frameworks.Twirp
 private import codeql.ruby.frameworks.Sqlite3
 private import codeql.ruby.frameworks.Pg
+private import codeql.ruby.frameworks.Sequel

ruby/ql/lib/codeql/ruby/frameworks/Sequel.qll

@@ -0,0 +1,71 @@
+/**
+ * Provides modeling for `Sequel`, the database toolkit for Ruby.
+ * https://github.com/jeremyevans/sequel
+ */
+
+private import ruby
+private import codeql.ruby.ApiGraphs
+private import codeql.ruby.dataflow.FlowSummary
+private import codeql.ruby.Concepts
+
+/**
+ * Provides modeling for `Sequel`, the database toolkit for Ruby.
+ * https://github.com/jeremyevans/sequel
+ */
+module Sequel {
+  /** Flow Summary for `Sequel`. */
+  private class SqlSummary extends SummarizedCallable {
+    SqlSummary() { this = "Sequel.connect" }
+
+    override MethodCall getACall() { result = any(SequelConnection c).asExpr().getExpr() }
+
+    override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
+      input = "Argument[0]" and output = "ReturnValue" and preservesValue = false
+    }
+  }
+
+  /** A call to establish a connection to a database */
+  private class SequelConnection extends DataFlow::CallNode {
+    SequelConnection() {
+      this =
+        API::getTopLevelMember("Sequel").getAMethodCall(["connect", "sqlite", "mysql2", "jdbc"])
+    }
+  }
+
+  /** A call that constructs SQL statements */
+  private class SequelConstruction extends SqlConstruction::Range, DataFlow::CallNode {
+    DataFlow::Node query;
+
+    SequelConstruction() {
+      this = API::getTopLevelMember("Sequel").getAMethodCall("cast") and query = this.getArgument(1)
+      or
+      this = API::getTopLevelMember("Sequel").getAMethodCall("function") and
+      query = this.getArgument(0)
+    }
+
+    override DataFlow::Node getSql() { result = query }
+  }
+
+  /** A call that executes SQL statements against a database */
+  private class SequelExecution extends SqlExecution::Range, DataFlow::CallNode {
+    SequelExecution() {
+      exists(SequelConnection sequelConnection |
+        this =
+          sequelConnection
+              .getAMethodCall([
+                  "execute", "execute_ddl", "execute_dui", "execute_insert", "run", "<<", "fetch",
+                  "fetch_rows", "[]", "log_connection_yield"
+                ]) or
+        this =
+          sequelConnection
+              .getAMethodCall("dataset")
+              .getAMethodCall([
+                  "with_sql", "with_sql_all", "with_sql_delete", "with_sql_each", "with_sql_first",
+                  "with_sql_insert", "with_sql_single_value", "with_sql_update"
+                ])
+      )
+    }
+
+    override DataFlow::Node getSql() { result = this.getArgument(0) }
+  }
+}

ruby/ql/test/library-tests/dataflow/local/TaintStep.expected

@@ -2815,6 +2815,7 @@
 | file://:0:0:0:0 | parameter position 0 of File.realpath | file://:0:0:0:0 | [summary] to write: return (return) in File.realpath |
 | file://:0:0:0:0 | parameter position 0 of Hash[] | file://:0:0:0:0 | [summary] read: argument position 0.any element in Hash[] |
 | file://:0:0:0:0 | parameter position 0 of PG.new() | file://:0:0:0:0 | [summary] to write: return (return) in PG.new() |
+| file://:0:0:0:0 | parameter position 0 of Sequel.connect | file://:0:0:0:0 | [summary] to write: return (return) in Sequel.connect |
 | file://:0:0:0:0 | parameter position 0 of String.try_convert | file://:0:0:0:0 | [summary] to write: return (return) in String.try_convert |
 | file://:0:0:0:0 | parameter position 0 of \| | file://:0:0:0:0 | [summary] read: argument position 0.any element in \| |
 | file://:0:0:0:0 | parameter position 1.. of File.join | file://:0:0:0:0 | [summary] to write: return (return) in File.join |

ruby/ql/test/library-tests/frameworks/sequel/Sequel.expected

@@ -0,0 +1,23 @@
+sequelSqlConstruction
+| sequel.rb:62:29:62:49 | call to cast | sequel.rb:62:45:62:48 | name |
+| sequel.rb:65:29:65:49 | call to function | sequel.rb:65:45:65:48 | name |
+sequelSqlExecution
+| sequel.rb:9:9:9:60 | ...[...] | sequel.rb:9:14:9:59 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:12:9:12:64 | call to run | sequel.rb:12:18:12:63 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:15:9:17:11 | call to fetch | sequel.rb:15:20:15:65 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:20:9:20:65 | ...[...] | sequel.rb:20:14:20:64 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:23:9:23:65 | call to execute | sequel.rb:23:22:23:65 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:26:9:26:71 | call to execute_ddl | sequel.rb:26:26:26:71 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:29:9:29:71 | call to execute_dui | sequel.rb:29:26:29:71 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:32:9:32:74 | call to execute_insert | sequel.rb:32:29:32:74 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:35:9:35:62 | ... << ... | sequel.rb:35:17:35:62 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:38:9:38:79 | call to fetch_rows | sequel.rb:38:25:38:70 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:41:9:41:81 | call to with_sql_all | sequel.rb:41:35:41:80 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:44:9:44:84 | call to with_sql_delete | sequel.rb:44:38:44:83 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:47:9:47:90 | call to with_sql_each | sequel.rb:47:36:47:81 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:50:9:50:83 | call to with_sql_first | sequel.rb:50:37:50:82 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:53:9:53:84 | call to with_sql_insert | sequel.rb:53:38:53:83 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:56:9:56:90 | call to with_sql_single_value | sequel.rb:56:44:56:89 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:59:9:59:84 | call to with_sql_update | sequel.rb:59:38:59:83 | "SELECT * FROM users WHERE use..." |
+| sequel.rb:62:9:62:20 | ...[...] | sequel.rb:62:14:62:19 | :table |
+| sequel.rb:65:9:65:20 | ...[...] | sequel.rb:65:14:65:19 | :table |

ruby/ql/test/library-tests/frameworks/sequel/Sequel.ql

@@ -0,0 +1,7 @@
+private import codeql.ruby.DataFlow
+private import codeql.ruby.Concepts
+private import codeql.ruby.frameworks.Sequel
+
+query predicate sequelSqlConstruction(SqlConstruction c, DataFlow::Node sql) { sql = c.getSql() }
+
+query predicate sequelSqlExecution(SqlExecution e, DataFlow::Node sql) { sql = e.getSql() }

ruby/ql/test/library-tests/frameworks/sequel/sequel.rb

@@ -0,0 +1,67 @@
+require 'sequel'
+
+class UsersController < ActionController::Base
+    def sequel_handler(event:, context:)
+        name = params[:name]
+        conn = Sequel.sqlite("sqlite://example.db")
+
+        # BAD: SQL statement constructed from user input
+        conn["SELECT * FROM users WHERE username='#{name}'"]
+
+        # BAD: SQL statement constructed from user input
+        conn.run("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.fetch("SELECT * FROM users WHERE username='#{name}'") do |row|
+            puts row[:name]
+        end
+
+        # GOOD: SQL statement is not constructed from user input
+        conn["SELECT * FROM users WHERE username='im_not_input'"]
+
+        # BAD: SQL statement constructed from user input
+        conn.execute "SELECT * FROM users WHERE username=#{name}"
+
+        # BAD: SQL statement constructed from user input
+        conn.execute_ddl "SELECT * FROM users WHERE username='#{name}'"
+
+        # BAD: SQL statement constructed from user input
+        conn.execute_dui "SELECT * FROM users WHERE username='#{name}'"
+
+        # BAD: SQL statement constructed from user input
+        conn.execute_insert "SELECT * FROM users WHERE username='#{name}'"
+
+        # BAD: SQL statement constructed from user input
+        conn << "SELECT * FROM users WHERE username='#{name}'"
+
+        # BAD: SQL statement constructed from user input
+        conn.fetch_rows("SELECT * FROM users WHERE username='#{name}'"){|row| }
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_all("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_delete("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_each("SELECT * FROM users WHERE username='#{name}'"){|row| }
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_first("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_insert("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_single_value("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn.dataset.with_sql_update("SELECT * FROM users WHERE username='#{name}'")
+
+        # BAD: SQL statement constructed from user input
+        conn[:table].select(Sequel.cast(:a, name)) 
+
+        # BAD: SQL statement constructed from user input
+        conn[:table].select(Sequel.function(name)) 
+    end
+end