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Wed, 17 Apr 2024 16:21:24 +0000 Received: from smtpav06.wdc07v.mail.ibm.com (smtpav06.wdc07v.mail.ibm.com [10.39.53.233]) by smtprelay03.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 43HGLLmv25035454 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Apr 2024 16:21:24 GMT Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 826315803F; Wed, 17 Apr 2024 16:21:21 +0000 (GMT) Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A69FD58056; Wed, 17 Apr 2024 16:21:20 +0000 (GMT) Received: from sbct-3.bos2.lab (unknown [9.47.158.153]) by smtpav06.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 17 Apr 2024 16:21:20 +0000 (GMT) From: Stefan Berger To: linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net Cc: linux-kernel@vger.kernel.org, jarkko@kernel.org, ardb@kernel.org, salvatore.benedetto@intel.com, git@jvdsn.com, Stefan Berger Subject: [PATCH v2 1/2] crypto: ecdh - Pass private key in proper byte order to check valid key Date: Wed, 17 Apr 2024 12:21:16 -0400 Message-ID: <20240417162117.2752326-2-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240417162117.2752326-1-stefanb@linux.ibm.com> References: <20240417162117.2752326-1-stefanb@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: CvN5zoxWixQPeOTPFhABapZPuf9QIzM6 X-Proofpoint-ORIG-GUID: CvN5zoxWixQPeOTPFhABapZPuf9QIzM6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-04-17_13,2024-04-16_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 mlxscore=0 spamscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 priorityscore=1501 mlxlogscore=999 phishscore=0 malwarescore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2404010000 definitions=main-2404170113 ecc_is_key_valid expects a key with the most significant digit in the last entry of the digit array. Currently ecdh_set_secret passes a reversed key to ecc_is_key_valid that then passes the rather simple test checking whether the private key is in range [2, n-3]. For all current ecdh- supported curves (NIST P192/256/384) the 'n' parameter is a rather large number, therefore easily passing this test. Throughout the ecdh and ecc codebase the variable 'priv' is used for a private_key holding the bytes in proper byte order. Therefore, introduce priv in ecdh_set_secret and copy the bytes from ctx->private_key into priv in proper byte order by using ecc_swap_digits. Pass priv to ecc_is_valid_key. Cc: Ard Biesheuvel Cc: Salvatore Benedetto Signed-off-by: Stefan Berger --- crypto/ecdh.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/crypto/ecdh.c b/crypto/ecdh.c index 3049f147e011..c02c9a2b9682 100644 --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -27,7 +27,9 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, unsigned int len) { struct ecdh_ctx *ctx = ecdh_get_ctx(tfm); + u64 priv[ECC_MAX_DIGITS]; struct ecdh params; + int ret = 0; if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || params.key_size > sizeof(u64) * ctx->ndigits) @@ -40,13 +42,16 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, ctx->private_key); memcpy(ctx->private_key, params.key, params.key_size); + ecc_swap_digits(ctx->private_key, priv, ctx->ndigits); if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits, - ctx->private_key, params.key_size) < 0) { + priv, params.key_size) < 0) { memzero_explicit(ctx->private_key, params.key_size); - return -EINVAL; + ret = -EINVAL; } - return 0; + memzero_explicit(priv, sizeof(priv)); + + return ret; } static int ecdh_compute_value(struct kpp_request *req)