WIP: Re-use cipher contexts for SMGR-level encryption

Author: jeltz

src/encryption/enc_aes.c

@@ -40,6 +40,9 @@ static const EVP_CIPHER *cipher_cbc_256 = NULL;
 static const EVP_CIPHER *cipher_gcm_256 = NULL;
 static const EVP_CIPHER *cipher_ctr_ecb_256 = NULL;
 
+static EVP_CIPHER_CTX *ctx_cbc_128 = NULL;
+static EVP_CIPHER_CTX *ctx_cbc_256 = NULL;
+
 void
 AesInit(void)
 {
@@ -52,6 +55,18 @@ AesInit(void)
 	cipher_cbc_256 = EVP_aes_256_cbc();
 	cipher_gcm_256 = EVP_aes_256_gcm();
 	cipher_ctr_ecb_256 = EVP_aes_256_ecb();
+
+	ctx_cbc_128 = EVP_CIPHER_CTX_new();
+	if (EVP_CipherInit_ex(ctx_cbc_128, cipher_cbc_128, NULL, NULL, NULL, 1) == 0)
+		ereport(ERROR,
+				errmsg("EVP_CipherInit_ex failed. OpenSSL error: %s", ERR_error_string(ERR_get_error(), NULL)));
+	EVP_CIPHER_CTX_set_padding(ctx_cbc_128, 0);
+
+	ctx_cbc_256 = EVP_CIPHER_CTX_new();
+	if (EVP_CipherInit_ex(ctx_cbc_256, cipher_cbc_256, NULL, NULL, NULL, 1) == 0)
+		ereport(ERROR,
+				errmsg("EVP_CipherInit_ex failed. OpenSSL error: %s", ERR_error_string(ERR_get_error(), NULL)));
+	EVP_CIPHER_CTX_set_padding(ctx_cbc_256, 0);
 }
 
 static void
@@ -94,23 +109,18 @@ AesRunCbc(int enc, const unsigned char *key, int key_len, const unsigned char *i
 {
 	int			out_len;
 	int			out_len_final;
-	EVP_CIPHER_CTX *ctx = NULL;
-	const EVP_CIPHER *cipher;
+	EVP_CIPHER_CTX *ctx;
 
 	Assert(key_len == 16 || key_len == 32);
-	cipher = key_len == 32 ? cipher_cbc_256 : cipher_cbc_128;
-
-	Assert(cipher != NULL);
-	Assert(in_len % EVP_CIPHER_block_size(cipher) == 0);
+	ctx = key_len == 32 ? ctx_cbc_128 : ctx_cbc_128;
 
-	ctx = EVP_CIPHER_CTX_new();
+	Assert(ctx != NULL);
+	Assert(in_len % EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ctx)) == 0);
 
-	if (EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc) == 0)
+	if (EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, enc) == 0)
 		ereport(ERROR,
 				errmsg("EVP_CipherInit_ex failed. OpenSSL error: %s", ERR_error_string(ERR_get_error(), NULL)));
 
-	EVP_CIPHER_CTX_set_padding(ctx, 0);
-
 	if (EVP_CipherUpdate(ctx, out, &out_len, in, in_len) == 0)
 		ereport(ERROR,
 				errmsg("EVP_CipherUpdate failed. OpenSSL error: %s", ERR_error_string(ERR_get_error(), NULL)));
@@ -125,8 +135,6 @@ AesRunCbc(int enc, const unsigned char *key, int key_len, const unsigned char *i
 	 */
 	out_len += out_len_final;
 	Assert(in_len == out_len);
-
-	EVP_CIPHER_CTX_free(ctx);
 }
 
 void