From 676a4ceb87e8c8e0811b4312ce4b3b74f53b4368 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Thu, 2 Sep 2021 09:57:06 +0200
Subject: stupidgcm: deduplicate tests 1/2

Pull the code shared between chacha and gcm into
generic functions.
---
 internal/stupidgcm/stupidchacha_test.go | 131 +++-----------------------------
 1 file changed, 11 insertions(+), 120 deletions(-)

(limited to 'internal/stupidgcm/stupidchacha_test.go')

diff --git a/internal/stupidgcm/stupidchacha_test.go b/internal/stupidgcm/stupidchacha_test.go
index 010055f..c1086d1 100644
--- a/internal/stupidgcm/stupidchacha_test.go
+++ b/internal/stupidgcm/stupidchacha_test.go
@@ -6,8 +6,6 @@
 package stupidgcm
 
 import (
-	"bytes"
-	"encoding/hex"
 	"testing"
 
 	"golang.org/x/crypto/chacha20poly1305"
@@ -17,46 +15,13 @@ import (
 // GCM implementation and verifies that the results are identical.
 func TestEncryptDecryptChacha(t *testing.T) {
 	key := randBytes(32)
-	sGCM := newChacha20poly1305(key)
-	authData := randBytes(24)
-	iv := randBytes(sGCM.NonceSize())
-	dst := make([]byte, 71) // 71 = random length
-
-	gGCM, err := chacha20poly1305.New(key)
+	c := newChacha20poly1305(key)
+	ref, err := chacha20poly1305.New(key)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	// Check all block sizes from 1 to 5000
-	for i := 1; i < 5000; i++ {
-		in := make([]byte, i)
-
-		sOut := sGCM.Seal(dst, iv, in, authData)
-		gOut := gGCM.Seal(dst, iv, in, authData)
-
-		// Ciphertext must be identical to Go GCM
-		if !bytes.Equal(sOut, gOut) {
-			t.Fatalf("Compare failed for encryption, size %d", i)
-			t.Log("sOut:")
-			t.Log("\n" + hex.Dump(sOut))
-			t.Log("gOut:")
-			t.Log("\n" + hex.Dump(gOut))
-		}
-
-		sOut2, sErr := sGCM.Open(dst, iv, sOut[len(dst):], authData)
-		if sErr != nil {
-			t.Fatal(sErr)
-		}
-		gOut2, gErr := gGCM.Open(dst, iv, gOut[len(dst):], authData)
-		if gErr != nil {
-			t.Fatal(gErr)
-		}
-
-		// Plaintext must be identical to Go GCM
-		if !bytes.Equal(sOut2, gOut2) {
-			t.Fatalf("Compare failed for decryption, size %d", i)
-		}
-	}
+	testEncryptDecrypt(t, c, ref)
 }
 
 // Seal re-uses the "dst" buffer it is large enough.
@@ -64,34 +29,13 @@ func TestEncryptDecryptChacha(t *testing.T) {
 // 5000 to 16 and "in" lengths from 1 to 5000.
 func TestInplaceSealChacha(t *testing.T) {
 	key := randBytes(32)
-	sGCM := newChacha20poly1305(key)
-	authData := randBytes(24)
-	iv := randBytes(sGCM.NonceSize())
-
-	gGCM, err := chacha20poly1305.New(key)
+	c := newChacha20poly1305(key)
+	ref, err := chacha20poly1305.New(key)
 	if err != nil {
 		t.Fatal(err)
 	}
-	max := 5016
-	// Check all block sizes from 1 to 5000
-	for i := 1; i < max-len(iv); i++ {
-		in := make([]byte, i)
-		dst := make([]byte, max-i)
-		dst = dst[:len(iv)]
-
-		sOut := sGCM.Seal(dst, iv, in, authData)
-		dst2 := make([]byte, len(iv))
-		gOut := gGCM.Seal(dst2, iv, in, authData)
 
-		// Ciphertext must be identical to Go GCM
-		if !bytes.Equal(sOut, gOut) {
-			t.Fatalf("Compare failed for encryption, size %d", i)
-			t.Log("sOut:")
-			t.Log("\n" + hex.Dump(sOut))
-			t.Log("gOut:")
-			t.Log("\n" + hex.Dump(gOut))
-		}
-	}
+	testInplaceSeal(t, c, ref)
 }
 
 // Open re-uses the "dst" buffer it is large enough.
@@ -99,73 +43,20 @@ func TestInplaceSealChacha(t *testing.T) {
 // 5000 to 16 and "in" lengths from 1 to 5000.
 func TestInplaceOpenChacha(t *testing.T) {
 	key := randBytes(32)
-	sGCM := newChacha20poly1305(key)
-	authData := randBytes(24)
-	iv := randBytes(sGCM.NonceSize())
-
-	gGCM, err := chacha20poly1305.New(key)
+	c := newChacha20poly1305(key)
+	ref, err := chacha20poly1305.New(key)
 	if err != nil {
 		t.Fatal(err)
 	}
-	max := 5016
-	// Check all block sizes from 1 to 5000
-	for i := 1; i < max-len(iv); i++ {
-		in := make([]byte, i)
-
-		gCiphertext := gGCM.Seal(iv, iv, in, authData)
 
-		dst := make([]byte, max-i)
-		// sPlaintext ... stupidgcm plaintext
-		sPlaintext, err := sGCM.Open(dst[:0], iv, gCiphertext[len(iv):], authData)
-		if err != nil {
-			t.Fatal(err)
-		}
-
-		// Plaintext must be identical to Go GCM
-		if !bytes.Equal(in, sPlaintext) {
-			t.Fatalf("Compare failed, i=%d", i)
-		}
-	}
+	testInplaceOpen(t, c, ref)
 }
 
 // TestCorruption verifies that changes in the ciphertext result in a decryption
 // error
 func TestCorruptionChacha(t *testing.T) {
 	key := randBytes(32)
-	sGCM := newChacha20poly1305(key)
-	authData := randBytes(24)
-	iv := randBytes(sGCM.NonceSize())
-
-	in := make([]byte, 354)
-	sOut := sGCM.Seal(nil, iv, in, authData)
-	sOut2, sErr := sGCM.Open(nil, iv, sOut, authData)
-	if sErr != nil {
-		t.Fatal(sErr)
-	}
-	if !bytes.Equal(in, sOut2) {
-		t.Fatalf("Compare failed")
-	}
+	c := newChacha20poly1305(key)
 
-	// Corrupt first byte
-	sOut[0]++
-	sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
-	if sErr == nil || sOut2 != nil {
-		t.Fatalf("Should have gotten error")
-	}
-	sOut[0]--
-
-	// Corrupt last byte
-	sOut[len(sOut)-1]++
-	sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
-	if sErr == nil || sOut2 != nil {
-		t.Fatalf("Should have gotten error")
-	}
-	sOut[len(sOut)-1]--
-
-	// Append one byte
-	sOut = append(sOut, 0)
-	sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
-	if sErr == nil || sOut2 != nil {
-		t.Fatalf("Should have gotten error")
-	}
+	testCorruption(t, c)
 }
-- 
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