From:   Stephan =?ISO-8859-1?Q?M=FCller?= <smueller@chronox.de>
To:     herbert@gondor.apana.org.au
Cc:     linux-crypto@vger.kernel.org
Subject: [PATCH] crypto: DH - limit key size to 2048 in FIPS mode
Date:   Sun, 21 Nov 2021 15:51:44 +0100
Message-ID: <2564099.lGaqSPkdTl@positron.chronox.de>
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Precedence: bulk

FIPS disallows DH with keys < 2048 bits. Thus, the kernel should
consider the enforcement of this limit.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
 crypto/dh.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/crypto/dh.c b/crypto/dh.c
index cd4f32092e5c..38557e64b4b3 100644
--- a/crypto/dh.c
+++ b/crypto/dh.c
@@ -5,6 +5,7 @@
  * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
  */
 
+#include <linux/fips.h>
 #include <linux/module.h>
 #include <crypto/internal/kpp.h>
 #include <crypto/kpp.h>
@@ -47,6 +48,9 @@ static inline struct dh_ctx *dh_get_ctx(struct crypto_kpp *tfm)
 
 static int dh_check_params_length(unsigned int p_len)
 {
+	if (fips_enabled)
+		return (p_len < 2048) ? -EINVAL : 0;
+
 	return (p_len < 1536) ? -EINVAL : 0;
 }
 
-- 
2.33.1