From 412ba1263bdaad8aab547a143efce10893fc559e Mon Sep 17 00:00:00 2001
From: Slavomir <gagliardetto@users.noreply.github.com>
Date: Sun, 6 Sep 2020 18:06:39 +0200
Subject: [PATCH] Add taint-tracking for `encoding/ascii85`

---
 ql/src/semmle/go/frameworks/Stdlib.qll        |  1 +
 .../go/frameworks/stdlib/EncodingAscii85.qll  | 35 +++++++++++
 .../StdlibTaintFlow/EncodingAscii85.go        | 59 +++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 ql/src/semmle/go/frameworks/stdlib/EncodingAscii85.qll
 create mode 100644 ql/test/library-tests/semmle/go/frameworks/StdlibTaintFlow/EncodingAscii85.go

diff --git a/ql/src/semmle/go/frameworks/Stdlib.qll b/ql/src/semmle/go/frameworks/Stdlib.qll
index 6de114d1735..8c62bda1a1d 100644
--- a/ql/src/semmle/go/frameworks/Stdlib.qll
+++ b/ql/src/semmle/go/frameworks/Stdlib.qll
@@ -16,6 +16,7 @@ import semmle.go.frameworks.stdlib.Mime
 import semmle.go.frameworks.stdlib.MimeMultipart
 import semmle.go.frameworks.stdlib.MimeQuotedprintable
 import semmle.go.frameworks.stdlib.Encoding
+import semmle.go.frameworks.stdlib.EncodingAscii85
 import semmle.go.frameworks.stdlib.Path
 import semmle.go.frameworks.stdlib.PathFilepath
 import semmle.go.frameworks.stdlib.Reflect
diff --git a/ql/src/semmle/go/frameworks/stdlib/EncodingAscii85.qll b/ql/src/semmle/go/frameworks/stdlib/EncodingAscii85.qll
new file mode 100644
index 00000000000..cb039ab4c0b
--- /dev/null
+++ b/ql/src/semmle/go/frameworks/stdlib/EncodingAscii85.qll
@@ -0,0 +1,35 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `encoding/ascii85` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `encoding/ascii85` package. */
+module EncodingAscii85 {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func Decode(dst []byte, src []byte, flush bool) (ndst int, nsrc int, err error)
+      hasQualifiedName("encoding/ascii85", "Decode") and
+      (inp.isParameter(1) and outp.isParameter(0))
+      or
+      // signature: func Encode(dst []byte, src []byte) int
+      hasQualifiedName("encoding/ascii85", "Encode") and
+      (inp.isParameter(1) and outp.isParameter(0))
+      or
+      // signature: func NewDecoder(r io.Reader) io.Reader
+      hasQualifiedName("encoding/ascii85", "NewDecoder") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func NewEncoder(w io.Writer) io.WriteCloser
+      hasQualifiedName("encoding/ascii85", "NewEncoder") and
+      (inp.isResult() and outp.isParameter(0))
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}
diff --git a/ql/test/library-tests/semmle/go/frameworks/StdlibTaintFlow/EncodingAscii85.go b/ql/test/library-tests/semmle/go/frameworks/StdlibTaintFlow/EncodingAscii85.go
new file mode 100644
index 00000000000..1bd73a0649d
--- /dev/null
+++ b/ql/test/library-tests/semmle/go/frameworks/StdlibTaintFlow/EncodingAscii85.go
@@ -0,0 +1,59 @@
+// Code generated by https://github.com/gagliardetto/codebox. DO NOT EDIT.
+
+package main
+
+import (
+	"encoding/ascii85"
+	"io"
+)
+
+func TaintStepTest_EncodingAscii85Decode_B0I0O0(sourceCQL interface{}) interface{} {
+	fromByte656 := sourceCQL.([]byte)
+	var intoByte414 []byte
+	ascii85.Decode(intoByte414, fromByte656, false)
+	return intoByte414
+}
+
+func TaintStepTest_EncodingAscii85Encode_B0I0O0(sourceCQL interface{}) interface{} {
+	fromByte518 := sourceCQL.([]byte)
+	var intoByte650 []byte
+	ascii85.Encode(intoByte650, fromByte518)
+	return intoByte650
+}
+
+func TaintStepTest_EncodingAscii85NewDecoder_B0I0O0(sourceCQL interface{}) interface{} {
+	fromReader784 := sourceCQL.(io.Reader)
+	intoReader957 := ascii85.NewDecoder(fromReader784)
+	return intoReader957
+}
+
+func TaintStepTest_EncodingAscii85NewEncoder_B0I0O0(sourceCQL interface{}) interface{} {
+	fromWriteCloser520 := sourceCQL.(io.WriteCloser)
+	var intoWriter443 io.Writer
+	intermediateCQL := ascii85.NewEncoder(intoWriter443)
+	link(fromWriteCloser520, intermediateCQL)
+	return intoWriter443
+}
+
+func RunAllTaints_EncodingAscii85() {
+	{
+		source := newSource(0)
+		out := TaintStepTest_EncodingAscii85Decode_B0I0O0(source)
+		sink(0, out)
+	}
+	{
+		source := newSource(1)
+		out := TaintStepTest_EncodingAscii85Encode_B0I0O0(source)
+		sink(1, out)
+	}
+	{
+		source := newSource(2)
+		out := TaintStepTest_EncodingAscii85NewDecoder_B0I0O0(source)
+		sink(2, out)
+	}
+	{
+		source := newSource(3)
+		out := TaintStepTest_EncodingAscii85NewEncoder_B0I0O0(source)
+		sink(3, out)
+	}
+}