Add taint-tracking for text/scanner package.

Author: gagliardetto

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

@@ -14,6 +14,7 @@ import semmle.go.frameworks.stdlib.CompressLzw
 import semmle.go.frameworks.stdlib.CompressZlib
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
+import semmle.go.frameworks.stdlib.TextScanner
 
 /** A `String()` method. */
 class StringMethod extends TaintTracking::FunctionModel, Method {

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

@@ -0,0 +1,30 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `text/scanner` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `text/scanner` package. */
+module TextScanner {
+  private class MethodModels extends TaintTracking::FunctionModel, Method {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    MethodModels() {
+      // signature: func (*Scanner).Init(src io.Reader) *Scanner
+      this.hasQualifiedName("text/scanner", "Scanner", "Init") and
+      (
+        inp.isParameter(0) and
+        (outp.isReceiver() or outp.isResult())
+      )
+      or
+      // signature: func (*Scanner).TokenText() string
+      this.hasQualifiedName("text/scanner", "Scanner", "TokenText") and
+      (inp.isReceiver() and outp.isResult())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}