Merge pull request #34 from microsoft/dev/qmuntal/nilseal

Initialize empty AES-GCM inputs
microsoft · Jul 27, 2022 · f0cde27 · f0cde27
2 parents 136d210 + 5909954
commit f0cde27
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Showing 2 changed files with 32 additions and 4 deletions.
diff --git a/openssl/aes_test.go b/openssl/aes_test.go
@@ -61,6 +61,28 @@ func TestSealAndOpen(t *testing.T) {
 	}
 }
 
+func TestSealAndOpen_Empty(t *testing.T) {
+	key := []byte("D249BF6DEC97B1EBD69BC4D6B3A3C49D")
+	ci, err := NewAESCipher(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c := ci.(*aesCipher)
+	gcm, err := c.NewGCM(gcmStandardNonceSize, gcmTagSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	nonce := []byte{0x91, 0xc7, 0xa7, 0x54, 0x52, 0xef, 0x10, 0xdb, 0x91, 0xa8, 0x6c, 0xf9}
+	sealed := gcm.Seal(nil, nonce, []byte{}, []byte{})
+	decrypted, err := gcm.Open(nil, nonce, sealed, []byte{})
+	if err != nil {
+		t.Error(err)
+	}
+	if !bytes.Equal(decrypted, []byte{}) {
+		t.Errorf("unexpected decrypted result\ngot: %#v\nexp: %#v", decrypted, []byte{})
+	}
+}
+
 func TestSealAndOpenTLS(t *testing.T) {
 	key := []byte("D249BF6DEC97B1EBD69BC4D6B3A3C49D")
 	ci, err := NewAESCipher(key)

diff --git a/openssl/goopenssl.h b/openssl/goopenssl.h
@@ -91,13 +91,16 @@ go_openssl_EVP_CIPHER_CTX_seal_wrapper(const GO_EVP_CIPHER_CTX_PTR ctx,
                                        unsigned char *out,
                                        const unsigned char *nonce,
                                        const unsigned char *in, int in_len,
-                                       const unsigned char *add, int add_len)
+                                       const unsigned char *aad, int aad_len)
 {
+    if (in_len == 0) in = "";
+    if (aad_len == 0) aad = "";
+
     if (go_openssl_EVP_CipherInit_ex(ctx, NULL, NULL, NULL, nonce, GO_AES_ENCRYPT) != 1)
         return 0;
 
     int discard_len, out_len;
-    if (go_openssl_EVP_EncryptUpdate(ctx, NULL, &discard_len, add, add_len) != 1
+    if (go_openssl_EVP_EncryptUpdate(ctx, NULL, &discard_len, aad, aad_len) != 1
         || go_openssl_EVP_EncryptUpdate(ctx, out, &out_len, in, in_len) != 1
         || go_openssl_EVP_EncryptFinal_ex(ctx, out + out_len, &discard_len) != 1)
     {
@@ -115,14 +118,17 @@ go_openssl_EVP_CIPHER_CTX_open_wrapper(const GO_EVP_CIPHER_CTX_PTR ctx,
                                        unsigned char *out,
                                        const unsigned char *nonce,
                                        const unsigned char *in, int in_len,
-                                       const unsigned char *add, int add_len,
+                                       const unsigned char *aad, int aad_len,
                                        const unsigned char *tag)
 {
+    if (in_len == 0) in = "";
+    if (aad_len == 0) aad = "";
+
     if (go_openssl_EVP_CipherInit_ex(ctx, NULL, NULL, NULL, nonce, GO_AES_DECRYPT) != 1)
         return 0;
 
     int discard_len, out_len;
-    if (go_openssl_EVP_DecryptUpdate(ctx, NULL, &discard_len, add, add_len) != 1
+    if (go_openssl_EVP_DecryptUpdate(ctx, NULL, &discard_len, aad, aad_len) != 1
         || go_openssl_EVP_DecryptUpdate(ctx, out, &out_len, in, in_len) != 1)
     {
         return 0;