Disable OpenSSL EVP digest padding in pgcrypto

danielgustafsson · danielgustafsson · commit 00c72da4a22d · 2021-09-25T11:27:20.000+02:00
The PX layer in pgcrypto is handling digest padding on its own uniformly for all backend implementations. Starting with OpenSSL 3.0.0, DecryptUpdate doesn't flush the last block in case padding is enabled so explicitly disable it as we don't use it. This will be backpatched to all supported version once there is sufficient testing in the buildfarm of OpenSSL 3. Reviewed-by: Peter Eisentraut, Michael Paquier Discussion: https://postgr.es/m/FEF81714-D479-4512-839B-C769D2605F8A@yesql.se Backpatch-through: 9.6
diff --git a/contrib/pgcrypto/openssl.c b/contrib/pgcrypto/openssl.c
@@ -380,6 +380,8 @@ gen_ossl_decrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
 	{
 		if (!EVP_DecryptInit_ex(od->evp_ctx, od->evp_ciph, NULL, NULL, NULL))
 			return PXE_CIPHER_INIT;
+		if (!EVP_CIPHER_CTX_set_padding(od->evp_ctx, 0))
+			return PXE_CIPHER_INIT;
 		if (!EVP_CIPHER_CTX_set_key_length(od->evp_ctx, od->klen))
 			return PXE_CIPHER_INIT;
 		if (!EVP_DecryptInit_ex(od->evp_ctx, NULL, NULL, od->key, od->iv))
@@ -404,6 +406,8 @@ gen_ossl_encrypt(PX_Cipher *c, const uint8 *data, unsigned dlen,
 	{
 		if (!EVP_EncryptInit_ex(od->evp_ctx, od->evp_ciph, NULL, NULL, NULL))
 			return PXE_CIPHER_INIT;
+		if (!EVP_CIPHER_CTX_set_padding(od->evp_ctx, 0))
+			return PXE_CIPHER_INIT;
 		if (!EVP_CIPHER_CTX_set_key_length(od->evp_ctx, od->klen))
 			return PXE_CIPHER_INIT;
 		if (!EVP_EncryptInit_ex(od->evp_ctx, NULL, NULL, od->key, od->iv))
