From 0ca128c9ee894f1b0067abd473bfb33171df67f8 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Mon, 16 Sep 2024 05:37:05 +0000 Subject: upstream: use 64 bit math to avoid signed underflow. upstream code relies on using -fwrapv to provide defined over/underflow behaviour, but we use -ftrapv to catch integer errors and abort the program. ok dtucker@ OpenBSD-Commit-ID: 8933369b33c17b5f02479503d0a92d87bc3a574b --- sntrup761.c | 14 +++++++------- sntrup761.sh | 7 ++++++- 2 files changed, 13 insertions(+), 8 deletions(-) diff --git a/sntrup761.c b/sntrup761.c index 6606e854f..123d01381 100644 --- a/sntrup761.c +++ b/sntrup761.c @@ -1,5 +1,5 @@ -/* $OpenBSD: sntrup761.c,v 1.7 2024/09/15 02:20:51 djm Exp $ */ +/* $OpenBSD: sntrup761.c,v 1.8 2024/09/16 05:37:05 djm Exp $ */ /* * Public Domain, Authors: @@ -917,8 +917,8 @@ crypto_int32 crypto_int32_min(crypto_int32 crypto_int32_x,crypto_int32 crypto_in __asm__ ("cmp %w0,%w1\n csel %w0,%w0,%w1,lt" : "+r"(crypto_int32_x) : "r"(crypto_int32_y) : "cc"); return crypto_int32_x; #else - crypto_int32 crypto_int32_r = crypto_int32_y ^ crypto_int32_x; - crypto_int32 crypto_int32_z = crypto_int32_y - crypto_int32_x; + crypto_int64 crypto_int32_r = (crypto_int64)crypto_int32_y ^ (crypto_int64)crypto_int32_x; + crypto_int64 crypto_int32_z = (crypto_int64)crypto_int32_y - (crypto_int64)crypto_int32_x; crypto_int32_z ^= crypto_int32_r & (crypto_int32_z ^ crypto_int32_y); crypto_int32_z = crypto_int32_negative_mask(crypto_int32_z); crypto_int32_z &= crypto_int32_r; @@ -936,8 +936,8 @@ crypto_int32 crypto_int32_max(crypto_int32 crypto_int32_x,crypto_int32 crypto_in __asm__ ("cmp %w0,%w1\n csel %w0,%w1,%w0,lt" : "+r"(crypto_int32_x) : "r"(crypto_int32_y) : "cc"); return crypto_int32_x; #else - crypto_int32 crypto_int32_r = crypto_int32_y ^ crypto_int32_x; - crypto_int32 crypto_int32_z = crypto_int32_y - crypto_int32_x; + crypto_int64 crypto_int32_r = (crypto_int64)crypto_int32_y ^ (crypto_int64)crypto_int32_x; + crypto_int64 crypto_int32_z = (crypto_int64)crypto_int32_y - (crypto_int64)crypto_int32_x; crypto_int32_z ^= crypto_int32_r & (crypto_int32_z ^ crypto_int32_y); crypto_int32_z = crypto_int32_negative_mask(crypto_int32_z); crypto_int32_z &= crypto_int32_r; @@ -961,8 +961,8 @@ void crypto_int32_minmax(crypto_int32 *crypto_int32_p,crypto_int32 *crypto_int32 *crypto_int32_p = crypto_int32_r; *crypto_int32_q = crypto_int32_s; #else - crypto_int32 crypto_int32_r = crypto_int32_y ^ crypto_int32_x; - crypto_int32 crypto_int32_z = crypto_int32_y - crypto_int32_x; + crypto_int64 crypto_int32_r = (crypto_int64)crypto_int32_y ^ (crypto_int64)crypto_int32_x; + crypto_int64 crypto_int32_z = (crypto_int64)crypto_int32_y - (crypto_int64)crypto_int32_x; crypto_int32_z ^= crypto_int32_r & (crypto_int32_z ^ crypto_int32_y); crypto_int32_z = crypto_int32_negative_mask(crypto_int32_z); crypto_int32_z &= crypto_int32_r; diff --git a/sntrup761.sh b/sntrup761.sh index 92c803bb1..4de8dc334 100644 --- a/sntrup761.sh +++ b/sntrup761.sh @@ -1,5 +1,5 @@ #!/bin/sh -# $OpenBSD: sntrup761.sh,v 1.8 2024/09/15 02:20:51 djm Exp $ +# $OpenBSD: sntrup761.sh,v 1.9 2024/09/16 05:37:05 djm Exp $ # Placed in the Public Domain. # AUTHOR="supercop-20240808/crypto_kem/sntrup761/ref/implementors" @@ -63,8 +63,13 @@ for i in $FILES; do -e "s/static void crypto_int16_minmax/void crypto_int16_minmax/" ;; */cryptoint/crypto_int32.h) + # Use int64_t for intermediate values in crypto_int32_minmax to + # prevent signed 32-bit integer overflow when called by + # crypto_sort_int32. Original code depends on -fwrapv (we set -ftrapv) sed -e "s/static void crypto_int32_store/void crypto_int32_store/" \ -e "s/^[#]define crypto_int32_optblocker.*//" \ + -e "s/crypto_int32 crypto_int32_r = crypto_int32_y ^ crypto_int32_x;/crypto_int64 crypto_int32_r = (crypto_int64)crypto_int32_y ^ (crypto_int64)crypto_int32_x;/" \ + -e "s/crypto_int32 crypto_int32_z = crypto_int32_y - crypto_int32_x;/crypto_int64 crypto_int32_z = (crypto_int64)crypto_int32_y - (crypto_int64)crypto_int32_x;/" \ -e "s/static void crypto_int32_minmax/void crypto_int32_minmax/" ;; */cryptoint/crypto_int64.h) -- cgit v1.2.3