File openssl-3-CVE-2023-3817.patch of Package openssl-3.34954
From 1c16253f3c3a8d1e25918c3f404aae6a5b0893de Mon Sep 17 00:00:00 2001
From: Tomas Mraz <tomas@openssl.org>
Date: Tue, 25 Jul 2023 15:22:48 +0200
Subject: [PATCH 179/200] DH_check(): Do not try checking q properties if it is
obviously invalid
If |q| >= |p| then the q value is obviously wrong as q
is supposed to be a prime divisor of p-1.
We check if p is overly large so this added test implies that
q is not large either when performing subsequent tests using that
q value.
Otherwise if it is too large these additional checks of the q value
such as the primality test can then trigger DoS by doing overly long
computations.
Fixes CVE-2023-3817
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from https://github.com/openssl/openssl/pull/21550)
---
crypto/dh/dh_check.c | 9 ++++++++-
test/dhtest.c | 12 ++++++++++++
2 files changed, 20 insertions(+), 1 deletion(-)
--- a/crypto/dh/dh_check.c
+++ b/crypto/dh/dh_check.c
@@ -143,7 +143,7 @@ int DH_check(const DH *dh, int *ret)
#ifdef FIPS_MODULE
return DH_check_params(dh, ret);
#else
- int ok = 0, r;
+ int ok = 0, r, q_good = 0;
BN_CTX *ctx = NULL;
BIGNUM *t1 = NULL, *t2 = NULL;
int nid = DH_get_nid((DH *)dh);
@@ -171,6 +171,13 @@ int DH_check(const DH *dh, int *ret)
goto err;
if (dh->params.q != NULL) {
+ if (BN_ucmp(dh->params.p, dh->params.q) > 0)
+ q_good = 1;
+ else
+ *ret |= DH_CHECK_INVALID_Q_VALUE;
+ }
+
+ if (q_good) {
if (BN_cmp(dh->params.g, BN_value_one()) <= 0)
*ret |= DH_NOT_SUITABLE_GENERATOR;
else if (BN_cmp(dh->params.g, dh->params.p) >= 0)
--- a/test/dhtest.c
+++ b/test/dhtest.c
@@ -124,6 +124,15 @@ static int dh_test(void)
/* We'll have a stale error on the queue from the above test so clear it */
ERR_clear_error();
+ if (!TEST_ptr(BN_copy(q, p)) || !TEST_true(BN_add(q, q, BN_value_one())))
+ goto err3;
+
+ if (!TEST_true(DH_check(dh, &i)))
+ goto err3;
+ if (!TEST_true(i & DH_CHECK_INVALID_Q_VALUE)
+ || !TEST_false(i & DH_CHECK_Q_NOT_PRIME))
+ goto err3;
+
/* Modulus of size: dh check max modulus bits + 1 */
if (!TEST_true(BN_set_word(p, 1))
|| !TEST_true(BN_lshift(p, p, OPENSSL_DH_CHECK_MAX_MODULUS_BITS)))
@@ -135,6 +144,9 @@ static int dh_test(void)
if (!TEST_false(DH_check(dh, &i)))
goto err3;
+ /* We'll have a stale error on the queue from the above test so clear it */
+ ERR_clear_error();
+
/*
* II) key generation
*/