From 14f2f9eb1a15f234f1ef417b8e62a6b7f950be4d Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Tue, 28 Nov 2023 08:35:50 +0900 Subject: [PATCH] Add CHECK_FOR_INTERRUPTS() in scram_SaltedPassword() for the backend scram_SaltedPassword() could take a long time to compute when the number of iterations used is large enough, and this code uses a tight loop to compute a salted password. Note that the same issue exists in libpq when using \password and a large iteration number, but this cannot be interrupted. A CFI in the backend is useful for server-side computations, at least. Backpatch down to 16, where the user-settable GUC scram_iterations has been added. Author: Bowen Shi Reviewed-by: Aleksander Alekseev, Daniel Gustafsson Discussion: https://postgr.es/m/CAM_vCueV6xfr08KczfaCEk5J_qeTZtgqN7+orkNLx=g+phE82Q@mail.gmail.com Backpatch-through: 16 --- src/common/scram-common.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/src/common/scram-common.c b/src/common/scram-common.c index ef997ef6849..6448564a08c 100644 --- a/src/common/scram-common.c +++ b/src/common/scram-common.c @@ -22,6 +22,9 @@ #include "common/base64.h" #include "common/hmac.h" #include "common/scram-common.h" +#ifndef FRONTEND +#include "miscadmin.h" +#endif #include "port/pg_bswap.h" /* @@ -73,6 +76,14 @@ scram_SaltedPassword(const char *password, /* Subsequent iterations */ for (i = 2; i <= iterations; i++) { +#ifndef FRONTEND + /* + * Make sure that this is interruptible as scram_iterations could be + * set to a large value. + */ + CHECK_FOR_INTERRUPTS(); +#endif + if (pg_hmac_init(hmac_ctx, (uint8 *) password, password_len) < 0 || pg_hmac_update(hmac_ctx, (uint8 *) Ui_prev, key_length) < 0 || pg_hmac_final(hmac_ctx, Ui, key_length) < 0)