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-rw-r--r--internal/stupidgcm/common_test.go152
1 files changed, 152 insertions, 0 deletions
diff --git a/internal/stupidgcm/common_test.go b/internal/stupidgcm/common_test.go
new file mode 100644
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--- /dev/null
+++ b/internal/stupidgcm/common_test.go
@@ -0,0 +1,152 @@
+package stupidgcm
+
+import (
+ "bytes"
+ "crypto/cipher"
+ "encoding/hex"
+ "testing"
+)
+
+// testEncryptDecrypt encrypts and decrypts using both stupidgcm and Go's built-in
+// GCM implementation and verifies that the results are identical.
+func testEncryptDecrypt(t *testing.T, c1 cipher.AEAD, c2 cipher.AEAD) {
+ if c1.NonceSize() != c2.NonceSize() {
+ t.Fatal("different NonceSize")
+ }
+ if c1.Overhead() != c2.Overhead() {
+ t.Fatal("different Overhead")
+ }
+
+ authData := randBytes(24)
+ iv := randBytes(c1.NonceSize())
+
+ dst := make([]byte, 71) // 71 = arbitrary length
+
+ // Check all block sizes from 1 to 5000
+ for i := 1; i < 5000; i++ {
+ in := make([]byte, i)
+
+ c1out := c1.Seal(dst, iv, in, authData)
+ c2out := c2.Seal(dst, iv, in, authData)
+
+ // Ciphertext must be identical to Go GCM
+ if !bytes.Equal(c1out, c2out) {
+ t.Fatalf("Compare failed for encryption, size %d", i)
+ t.Log("c1out:")
+ t.Log("\n" + hex.Dump(c1out))
+ t.Log("c2out:")
+ t.Log("\n" + hex.Dump(c2out))
+ }
+
+ c1out2, sErr := c1.Open(dst, iv, c1out[len(dst):], authData)
+ if sErr != nil {
+ t.Fatal(sErr)
+ }
+ c2out2, gErr := c2.Open(dst, iv, c2out[len(dst):], authData)
+ if gErr != nil {
+ t.Fatal(gErr)
+ }
+
+ // Plaintext must be identical to Go GCM
+ if !bytes.Equal(c1out2, c2out2) {
+ t.Fatalf("Compare failed for decryption, size %d", i)
+ }
+ }
+}
+
+// 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, c1 cipher.AEAD, c2 cipher.AEAD) {
+ authData := randBytes(24)
+ iv := randBytes(c1.NonceSize())
+
+ 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]
+
+ c1out := c1.Seal(dst, iv, in, authData)
+ dst2 := make([]byte, 16)
+ c2out := c2.Seal(dst2, iv, in, authData)
+
+ // Ciphertext must be identical to Go GCM
+ if !bytes.Equal(c1out, c2out) {
+ t.Fatalf("Compare failed for encryption, size %d", i)
+ t.Log("sOut:")
+ t.Log("\n" + hex.Dump(c1out))
+ t.Log("gOut:")
+ t.Log("\n" + hex.Dump(c2out))
+ }
+ }
+}
+
+// testInplaceOpen - Open 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 testInplaceOpen(t *testing.T, c1 cipher.AEAD, c2 cipher.AEAD) {
+ authData := randBytes(24)
+ iv := randBytes(c1.NonceSize())
+
+ max := 5016
+ // Check all block sizes from 1 to 5000
+ for i := 1; i < max-c1.NonceSize(); i++ {
+ in := make([]byte, i)
+
+ c2ciphertext := c2.Seal(iv, iv, in, authData)
+
+ dst := make([]byte, max-i)
+ // sPlaintext ... stupidgcm plaintext
+ c1plaintext, err := c1.Open(dst[:0], iv, c2ciphertext[c1.NonceSize():], authData)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ // Plaintext must be identical to Go GCM
+ if !bytes.Equal(in, c1plaintext) {
+ t.Fatalf("Compare failed, i=%d", i)
+ }
+ }
+}
+
+// testCorruption verifies that changes in the ciphertext result in a decryption
+// error
+func testCorruption(t *testing.T, c cipher.AEAD) {
+ authData := randBytes(24)
+ iv := randBytes(c.NonceSize())
+
+ in := make([]byte, 354)
+ out := c.Seal(nil, iv, in, authData)
+ out2, sErr := c.Open(nil, iv, out, authData)
+ if sErr != nil {
+ t.Fatal(sErr)
+ }
+ if !bytes.Equal(in, out2) {
+ t.Fatalf("Compare failed")
+ }
+
+ // Corrupt first byte
+ out[0]++
+ out2, sErr = c.Open(nil, iv, out, authData)
+ if sErr == nil || out2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+ out[0]--
+
+ // Corrupt last byte
+ out[len(out)-1]++
+ out2, sErr = c.Open(nil, iv, out, authData)
+ if sErr == nil || out2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+ out[len(out)-1]--
+
+ // Append one byte
+ out = append(out, 0)
+ out2, sErr = c.Open(nil, iv, out, authData)
+ if sErr == nil || out2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+}