Add taint-tracking for encoding/pem

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

@@ -25,6 +25,7 @@ import semmle.go.frameworks.stdlib.EncodingCsv
 import semmle.go.frameworks.stdlib.EncodingGob
 import semmle.go.frameworks.stdlib.EncodingHex
 import semmle.go.frameworks.stdlib.EncodingJson
+import semmle.go.frameworks.stdlib.EncodingPem
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
 import semmle.go.frameworks.stdlib.Reflect

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

@@ -0,0 +1,31 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `encoding/pem` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `encoding/pem` package. */
+module EncodingPem {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func Decode(data []byte) (p *Block, rest []byte)
+      hasQualifiedName("encoding/pem", "Decode") and
+      (inp.isParameter(0) and outp.isResult(_))
+      or
+      // signature: func Encode(out io.Writer, b *Block) error
+      hasQualifiedName("encoding/pem", "Encode") and
+      (inp.isParameter(1) and outp.isParameter(0))
+      or
+      // signature: func EncodeToMemory(b *Block) []byte
+      hasQualifiedName("encoding/pem", "EncodeToMemory") and
+      (inp.isParameter(0) and outp.isResult())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}

ql/test/library-tests/semmle/go/frameworks/StdlibTaintFlow/EncodingPem.go

@@ -0,0 +1,56 @@
+// Code generated by https://github.com/gagliardetto/codebox. DO NOT EDIT.
+
+package main
+
+import (
+	"encoding/pem"
+	"io"
+)
+
+func TaintStepTest_EncodingPemDecode_B0I0O0(sourceCQL interface{}) interface{} {
+	fromByte656 := sourceCQL.([]byte)
+	intoBlock414, _ := pem.Decode(fromByte656)
+	return intoBlock414
+}
+
+func TaintStepTest_EncodingPemDecode_B0I0O1(sourceCQL interface{}) interface{} {
+	fromByte518 := sourceCQL.([]byte)
+	_, intoByte650 := pem.Decode(fromByte518)
+	return intoByte650
+}
+
+func TaintStepTest_EncodingPemEncode_B0I0O0(sourceCQL interface{}) interface{} {
+	fromBlock784 := sourceCQL.(*pem.Block)
+	var intoWriter957 io.Writer
+	pem.Encode(intoWriter957, fromBlock784)
+	return intoWriter957
+}
+
+func TaintStepTest_EncodingPemEncodeToMemory_B0I0O0(sourceCQL interface{}) interface{} {
+	fromBlock520 := sourceCQL.(*pem.Block)
+	intoByte443 := pem.EncodeToMemory(fromBlock520)
+	return intoByte443
+}
+
+func RunAllTaints_EncodingPem() {
+	{
+		source := newSource(0)
+		out := TaintStepTest_EncodingPemDecode_B0I0O0(source)
+		sink(0, out)
+	}
+	{
+		source := newSource(1)
+		out := TaintStepTest_EncodingPemDecode_B0I0O1(source)
+		sink(1, out)
+	}
+	{
+		source := newSource(2)
+		out := TaintStepTest_EncodingPemEncode_B0I0O0(source)
+		sink(2, out)
+	}
+	{
+		source := newSource(3)
+		out := TaintStepTest_EncodingPemEncodeToMemory_B0I0O0(source)
+		sink(3, out)
+	}
+}