Add taint-tracking for mime/quotedprintable 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.Mime
 import semmle.go.frameworks.stdlib.MimeMultipart
+import semmle.go.frameworks.stdlib.MimeQuotedprintable
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
 

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

@@ -0,0 +1,46 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `mime/quotedprintable` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `mime/quotedprintable` package. */
+module MimeQuotedprintable {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func NewReader(r io.Reader) *Reader
+      hasQualifiedName("mime/quotedprintable", "NewReader") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func NewWriter(w io.Writer) *Writer
+      hasQualifiedName("mime/quotedprintable", "NewWriter") and
+      (inp.isResult() and outp.isParameter(0))
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+
+  private class MethodModels extends TaintTracking::FunctionModel, Method {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    MethodModels() {
+      // signature: func (*Reader).Read(p []byte) (n int, err error)
+      this.hasQualifiedName("mime/quotedprintable", "Reader", "Read") and
+      (inp.isReceiver() and outp.isParameter(0))
+      or
+      // signature: func (*Writer).Write(p []byte) (n int, err error)
+      this.hasQualifiedName("mime/quotedprintable", "Writer", "Write") and
+      (inp.isParameter(0) and outp.isReceiver())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}