Add taint-tracking for html package.

Author: gagliardetto

ql/src/semmle/go/frameworks/Stdlib.qll

@@ -27,6 +27,7 @@ import semmle.go.frameworks.stdlib.EncodingHex
 import semmle.go.frameworks.stdlib.EncodingJson
 import semmle.go.frameworks.stdlib.EncodingPem
 import semmle.go.frameworks.stdlib.EncodingXml
+import semmle.go.frameworks.stdlib.Html
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
 import semmle.go.frameworks.stdlib.Reflect

ql/src/semmle/go/frameworks/stdlib/Html.qll

@@ -0,0 +1,27 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `html` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `html` package. */
+module Html {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func EscapeString(s string) string
+      hasQualifiedName("html", "EscapeString") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func UnescapeString(s string) string
+      hasQualifiedName("html", "UnescapeString") and
+      (inp.isParameter(0) and outp.isResult())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}