Add taint-tracking for encoding/gob

Author: gagliardetto

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

@@ -22,6 +22,7 @@ import semmle.go.frameworks.stdlib.EncodingBase32
 import semmle.go.frameworks.stdlib.EncodingBase64
 import semmle.go.frameworks.stdlib.EncodingBinary
 import semmle.go.frameworks.stdlib.EncodingCsv
+import semmle.go.frameworks.stdlib.EncodingGob
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
 import semmle.go.frameworks.stdlib.Reflect

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

@@ -0,0 +1,62 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `encoding/gob` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `encoding/gob` package. */
+module EncodingGob {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func NewDecoder(r io.Reader) *Decoder
+      hasQualifiedName("encoding/gob", "NewDecoder") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func NewEncoder(w io.Writer) *Encoder
+      hasQualifiedName("encoding/gob", "NewEncoder") 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 (*Decoder).Decode(e interface{}) error
+      this.hasQualifiedName("encoding/gob", "Decoder", "Decode") and
+      (inp.isReceiver() and outp.isParameter(0))
+      or
+      // signature: func (*Decoder).DecodeValue(v reflect.Value) error
+      this.hasQualifiedName("encoding/gob", "Decoder", "DecodeValue") and
+      (inp.isReceiver() and outp.isParameter(0))
+      or
+      // signature: func (*Encoder).Encode(e interface{}) error
+      this.hasQualifiedName("encoding/gob", "Encoder", "Encode") and
+      (inp.isParameter(0) and outp.isReceiver())
+      or
+      // signature: func (*Encoder).EncodeValue(value reflect.Value) error
+      this.hasQualifiedName("encoding/gob", "Encoder", "EncodeValue") and
+      (inp.isParameter(0) and outp.isReceiver())
+      or
+      // signature: func (GobDecoder).GobDecode([]byte) error
+      this.implements("encoding/gob", "GobDecoder", "GobDecode") and
+      (inp.isParameter(0) and outp.isReceiver())
+      or
+      // signature: func (GobEncoder).GobEncode() ([]byte, error)
+      this.implements("encoding/gob", "GobEncoder", "GobEncode") and
+      (inp.isReceiver() and outp.isResult(0))
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}