From 3d25bcc75765a2fdecd754a39e5bdb79b2aef2ae Mon Sep 17 00:00:00 2001
From: AdamKorcz <44787359+AdamKorcz@users.noreply.github.com>
Date: Fri, 21 Oct 2022 10:14:03 +0100
Subject: [PATCH] golang: add encoding fuzzer (#8829)

Signed-off-by: AdamKorcz <adam@adalogics.com>

Signed-off-by: AdamKorcz <adam@adalogics.com>
---
 projects/golang/Dockerfile         |  1 +
 projects/golang/build.sh           |  3 ++
 projects/golang/encoding_fuzzer.go | 71 ++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+)
 create mode 100644 projects/golang/encoding_fuzzer.go

diff --git a/projects/golang/Dockerfile b/projects/golang/Dockerfile
index 9083d8bdc..5769bfd7b 100644
--- a/projects/golang/Dockerfile
+++ b/projects/golang/Dockerfile
@@ -43,6 +43,7 @@ COPY build.sh text_fuzzer.go \
      filepath_fuzzer.go \
      strings_fuzzer.go \
      multipart_fuzzer.go \
+     encoding_fuzzer.go \
      glob_fuzzer.options $SRC/
 
 WORKDIR $SRC/golang
diff --git a/projects/golang/build.sh b/projects/golang/build.sh
index b402de380..7e013ab61 100755
--- a/projects/golang/build.sh
+++ b/projects/golang/build.sh
@@ -47,12 +47,15 @@ function setup_golang_fuzzers() {
 
 	cp $SRC/multipart_fuzzer.go $SRC/golang/multipart/main.go
 
+	mkdir $SRC/golang/encoding && cp $SRC/encoding_fuzzer.go $SRC/golang/encoding/
+
 	go mod init "github.com/dvyukov/go-fuzz-corpus"
 }
 
 function compile_fuzzers() {
 	# version is used as suffix for the binaries
 	version=$1
+	compile_go_fuzzer $FUZZ_ROOT/encoding FuzzEncoding fuzz_encoding$version
 	compile_go_fuzzer $FUZZ_ROOT/strings FuzzStringsSplit fuzz_strings_split$version
 	compile_go_fuzzer $FUZZ_ROOT/fp FuzzFpGlob glob_fuzzer$version
 	compile_go_fuzzer $FUZZ_ROOT/crypto/x509 FuzzParseCert fuzz_parse_cert$version
diff --git a/projects/golang/encoding_fuzzer.go b/projects/golang/encoding_fuzzer.go
new file mode 100644
index 000000000..2f2c01656
--- /dev/null
+++ b/projects/golang/encoding_fuzzer.go
@@ -0,0 +1,71 @@
+package encoding
+
+import (
+	"bytes"
+	"encoding/base32"
+	"encoding/base64"
+	"encoding/gob"
+	"encoding/json"
+	"encoding/xml"
+	"runtime"
+	fuzz "github.com/AdaLogics/go-fuzz-headers"
+)
+
+func FuzzEncoding(data []byte) int {
+	f := fuzz.NewConsumer(data)
+	decType, err := f.GetInt()
+	if err != nil {
+		return 0
+	}
+	b1, err := f.GetBytes()
+	if err != nil {
+		return 0
+	}
+	b2, err := f.GetBytes()
+	if err != nil {
+		return 0
+	}
+	defer func() {
+		if r := recover(); r != nil {
+		}
+		runtime.GC()
+	}()
+	switch decType%5 {
+	case 0:
+		e, err := f.GetString()
+		if err != nil || len(e) != 32 {
+			return 0
+		}
+		enc := base32.NewEncoding(e)
+		d := base32.NewDecoder(enc, bytes.NewReader(b1))
+		_, _ = d.Read(b2)
+		return 1
+	case 1:
+		e, err := f.GetString()
+		if err != nil || len(e) != 64 {
+			return 0
+		}
+		for i := 0; i < len(e); i++ {
+			if e[i] == '\n' || e[i] == '\r' {
+				return 0
+			}
+		}
+		enc := base64.NewEncoding(e)
+		d := base64.NewDecoder(enc, bytes.NewReader(b1))
+		_, _ = d.Read(b2)
+		return 1
+	case 2:
+		d := gob.NewDecoder(bytes.NewReader(b1))
+		_ = d.Decode(b2)
+		return 1
+	case 3:
+		d := json.NewDecoder(bytes.NewReader(b1))
+		_ = d.Decode(b2)
+		return 1
+	case 4:
+		d := xml.NewDecoder(bytes.NewReader(b1))
+		_, _ = d.Token()
+		return 1
+	}
+	return 1
+}