Disable OpenSSL EVP digest padding in pgcrypto

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
index cfb73de719158a2aaa47be7680d7c215e53a3b95..3411f3afed7365c68fa388d8336e1ddecfab476c 100644 (file)
--- 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))