Implement models for translation methods

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

@@ -30,6 +30,7 @@ private import codeql.ruby.frameworks.Json
 private import codeql.ruby.frameworks.Erb
 private import codeql.ruby.frameworks.Slim
 private import codeql.ruby.frameworks.Sinatra
+private import codeql.ruby.frameworks.Translation
 private import codeql.ruby.frameworks.Twirp
 private import codeql.ruby.frameworks.Sqlite3
 private import codeql.ruby.frameworks.Mysql2

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

@@ -0,0 +1,66 @@
+/** Provides modeling for the `I18n` translation method and the rails translation helpers. */
+
+private import codeql.ruby.ApiGraphs
+private import codeql.ruby.dataflow.FlowSummary
+private import codeql.ruby.Concepts
+private import codeql.ruby.frameworks.ActionView
+
+/** Gets a call to `I18n.translate`, which can use keyword arguments as inputs for string interpolation. */
+private MethodCall getI18nTranslateCall() {
+  result = API::getTopLevelMember("I18n").getAMethodCall(["t", "translate"]).asExpr().getExpr()
+}
+
+/**
+ * Gets a call to the rails view helper translate method, which is a wrapper around `I18n.translate`
+ * that can also escape html if the key ends in `_html` or `.html`.
+ */
+private MethodCall getViewHelperTranslateCall() {
+  result.getMethodName() = ["t", "translate"] and
+  inActionViewContext(result)
+}
+
+/**
+ * Gets a call to the rails controller helper translate method, which is a wrapper around `I18n.translate`
+ * that can also escape html if the key ends in `_html` or `.html`.
+ */
+private MethodCall getControllerHelperTranslateCall() {
+  result =
+    API::getTopLevelMember("ActionController")
+        .getMember("Base")
+        .getInstance()
+        .getAMethodCall(["t", "translate"])
+        .asExpr()
+        .getExpr()
+}
+
+/** Flow summary for translation methods. */
+private class TranslateSummary extends SummarizedCallable {
+  TranslateSummary() { this = "I18n.translate" }
+
+  override MethodCall getACall() {
+    result =
+      [getI18nTranslateCall(), getViewHelperTranslateCall(), getControllerHelperTranslateCall()]
+  }
+
+  override predicate propagatesFlow(string input, string output, boolean preservesValue) {
+    input = "Argument[hash-splat].Element[any]" and
+    output = "ReturnValue" and
+    preservesValue = false
+  }
+}
+
+/** A call to a translation helper method that escapes HTML. */
+private class TranslateHtmlEscape extends Escaping::Range, DataFlow::CallNode {
+  TranslateHtmlEscape() {
+    exists(MethodCall mc | mc = this.asExpr().getExpr() |
+      mc = [getViewHelperTranslateCall(), getControllerHelperTranslateCall()] and
+      mc.getArgument(0).getConstantValue().getStringlikeValue().matches(["%\\_html", "%.html"])
+    )
+  }
+
+  override string getKind() { result = Escaping::getHtmlKind() }
+
+  override DataFlow::Node getAnInput() { result = this.getKeywordArgument(_) }
+
+  override DataFlow::Node getOutput() { result = this }
+}