From 7e0fefe970b98be7e455f671dbd0e994abd52110 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher <jakobunt@gmail.com>
Date: Sat, 17 Feb 2018 15:02:01 +0100
Subject: [PATCH] stupidgcm: switch to pointer receivers

What the key slice does not get copied around
will make it possible to check if the key has been wiped.
---
 internal/stupidgcm/stupidgcm.go       | 11 ++++++-----
 internal/stupidgcm/without_openssl.go | 12 ++++++------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/internal/stupidgcm/stupidgcm.go b/internal/stupidgcm/stupidgcm.go
index d690f93..2660808 100644
--- a/internal/stupidgcm/stupidgcm.go
+++ b/internal/stupidgcm/stupidgcm.go
@@ -29,6 +29,7 @@ type stupidGCM struct {
 	forceDecode bool
 }
 
+// Verify that we satisfy the cipher.AEAD interface
 var _ cipher.AEAD = &stupidGCM{}
 
 // New returns a new cipher.AEAD implementation..
@@ -36,19 +37,19 @@ func New(key []byte, forceDecode bool) cipher.AEAD {
 	if len(key) != keyLen {
 		log.Panicf("Only %d-byte keys are supported", keyLen)
 	}
-	return stupidGCM{key: key, forceDecode: forceDecode}
+	return &stupidGCM{key: key, forceDecode: forceDecode}
 }
 
-func (g stupidGCM) NonceSize() int {
+func (g *stupidGCM) NonceSize() int {
 	return ivLen
 }
 
-func (g stupidGCM) Overhead() int {
+func (g *stupidGCM) Overhead() int {
 	return tagLen
 }
 
 // Seal encrypts "in" using "iv" and "authData" and append the result to "dst"
-func (g stupidGCM) Seal(dst, iv, in, authData []byte) []byte {
+func (g *stupidGCM) Seal(dst, iv, in, authData []byte) []byte {
 	if len(iv) != ivLen {
 		log.Panicf("Only %d-byte IVs are supported", ivLen)
 	}
@@ -132,7 +133,7 @@ func (g stupidGCM) Seal(dst, iv, in, authData []byte) []byte {
 }
 
 // Open decrypts "in" using "iv" and "authData" and append the result to "dst"
-func (g stupidGCM) Open(dst, iv, in, authData []byte) ([]byte, error) {
+func (g *stupidGCM) Open(dst, iv, in, authData []byte) ([]byte, error) {
 	if len(iv) != ivLen {
 		log.Panicf("Only %d-byte IVs are supported", ivLen)
 	}
diff --git a/internal/stupidgcm/without_openssl.go b/internal/stupidgcm/without_openssl.go
index efd37f3..0c1c149 100644
--- a/internal/stupidgcm/without_openssl.go
+++ b/internal/stupidgcm/without_openssl.go
@@ -21,28 +21,28 @@ func errExit() {
 	os.Exit(exitcodes.OpenSSL)
 }
 
-func New(_ []byte, _ bool) stupidGCM {
+func New(_ []byte, _ bool) *stupidGCM {
 	errExit()
 	// Never reached
-	return stupidGCM{}
+	return &stupidGCM{}
 }
 
-func (g stupidGCM) NonceSize() int {
+func (g *stupidGCM) NonceSize() int {
 	errExit()
 	return -1
 }
 
-func (g stupidGCM) Overhead() int {
+func (g *stupidGCM) Overhead() int {
 	errExit()
 	return -1
 }
 
-func (g stupidGCM) Seal(_, _, _, _ []byte) []byte {
+func (g *stupidGCM) Seal(_, _, _, _ []byte) []byte {
 	errExit()
 	return nil
 }
 
-func (g stupidGCM) Open(_, _, _, _ []byte) ([]byte, error) {
+func (g *stupidGCM) Open(_, _, _, _ []byte) ([]byte, error) {
 	errExit()
 	return nil, nil
 }