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authorJakob Unterwurzacher2017-06-29 18:52:33 +0200
committerJakob Unterwurzacher2017-06-29 18:52:33 +0200
commit0cc6f53496d71ff3b8150f32116741147c1cab27 (patch)
tree21a4dc8b826102a0f8ef608158da77305a431af5 /internal/stupidgcm/stupidgcm_test.go
parentc12a50d4c8c24ff55d682b2fed1923be4f87f182 (diff)
stupidgcm: use "dst" as the output buffer it is big enough
This saves an allocation of the ciphertext block.
Diffstat (limited to 'internal/stupidgcm/stupidgcm_test.go')
-rw-r--r--internal/stupidgcm/stupidgcm_test.go39
1 files changed, 39 insertions, 0 deletions
diff --git a/internal/stupidgcm/stupidgcm_test.go b/internal/stupidgcm/stupidgcm_test.go
index eb322f2..4d37d08 100644
--- a/internal/stupidgcm/stupidgcm_test.go
+++ b/internal/stupidgcm/stupidgcm_test.go
@@ -73,6 +73,45 @@ func TestEncryptDecrypt(t *testing.T) {
}
}
+// Seal re-uses the "dst" buffer it is large enough.
+// Check that this works correctly by testing different "dst" capacities from
+// 5000 to 16 and "in" lengths from 1 to 5000.
+func TestInplaceSeal(t *testing.T) {
+ key := randBytes(32)
+ sGCM := New(key, false)
+ authData := randBytes(24)
+ iv := randBytes(16)
+
+ gAES, err := aes.NewCipher(key)
+ if err != nil {
+ t.Fatal(err)
+ }
+ gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
+ if err != nil {
+ t.Fatal(err)
+ }
+ max := 5016
+ // Check all block sizes from 1 to 5000
+ for i := 1; i < max-16; i++ {
+ in := make([]byte, i)
+ dst := make([]byte, max-i)
+ dst = dst[:16]
+
+ sOut := sGCM.Seal(dst, iv, in, authData)
+ dst2 := make([]byte, 16)
+ 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))
+ }
+ }
+}
+
// TestCorruption verifies that changes in the ciphertext result in a decryption
// error
func TestCorruption(t *testing.T) {