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Subject: Re: [PATCH 1/7] crypto: fix a memory leak in sm2
To:     Hongbo Li <herbert.tencent@gmail.com>, keyrings@vger.kernel.org,
        linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au,
        dhowells@redhat.com, jarkko@kernel.org, herberthbli@tencent.com,
        stable@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org
References: <1620828254-25545-1-git-send-email-herbert.tencent@gmail.com>
 <1620828254-25545-2-git-send-email-herbert.tencent@gmail.com>
From:   Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Message-ID: <246ad441-76c9-0934-d132-42d263d63195@linux.alibaba.com>
Date:   Fri, 14 May 2021 12:52:29 +0800
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Hi Hongbo,

On 5/12/21 10:04 PM, Hongbo Li wrote:
> From: Hongbo Li <herberthbli@tencent.com>
> 
> SM2 module alloc ec->Q in sm2_set_pub_key(), when doing alg test in
> test_akcipher_one(), it will set public key for every test vector,
> and don't free ec->Q. This will cause a memory leak.
> 
> This patch alloc ec->Q in sm2_ec_ctx_init().
> 
> Signed-off-by: Hongbo Li <herberthbli@tencent.com>
> ---
>   crypto/sm2.c | 24 ++++++++++--------------
>   1 file changed, 10 insertions(+), 14 deletions(-)
> 
> diff --git a/crypto/sm2.c b/crypto/sm2.c
> index b21addc..db8a4a2 100644
> --- a/crypto/sm2.c
> +++ b/crypto/sm2.c
> @@ -79,10 +79,17 @@ static int sm2_ec_ctx_init(struct mpi_ec_ctx *ec)
>   		goto free;
>   
>   	rc = -ENOMEM;
> +
> +	ec->Q = mpi_point_new(0);
> +	if (!ec->Q)
> +		goto free;
> +
>   	/* mpi_ec_setup_elliptic_curve */
>   	ec->G = mpi_point_new(0);
> -	if (!ec->G)
> +	if (!ec->G) {
> +		mpi_point_release(ec->Q);
>   		goto free;
> +	}
>   
>   	mpi_set(ec->G->x, x);
>   	mpi_set(ec->G->y, y);
> @@ -91,6 +98,7 @@ static int sm2_ec_ctx_init(struct mpi_ec_ctx *ec)
>   	rc = -EINVAL;
>   	ec->n = mpi_scanval(ecp->n);
>   	if (!ec->n) {
> +		mpi_point_release(ec->Q);
>   		mpi_point_release(ec->G);
>   		goto free;
>   	}
> @@ -386,27 +394,15 @@ static int sm2_set_pub_key(struct crypto_akcipher *tfm,
>   	MPI a;
>   	int rc;
>   
> -	ec->Q = mpi_point_new(0);
> -	if (!ec->Q)
> -		return -ENOMEM;
> -
>   	/* include the uncompressed flag '0x04' */
> -	rc = -ENOMEM;
>   	a = mpi_read_raw_data(key, keylen);
>   	if (!a)
> -		goto error;
> +		return -ENOMEM;
>   
>   	mpi_normalize(a);
>   	rc = sm2_ecc_os2ec(ec->Q, a);
>   	mpi_free(a);
> -	if (rc)
> -		goto error;
> -
> -	return 0;
>   
> -error:
> -	mpi_point_release(ec->Q);
> -	ec->Q = NULL;
>   	return rc;
>   }
>   
> 

Thanks a lot for fixing this issue.

Reviewed-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>

Also added:

Cc: stable@vger.kernel.org # v5.10+

Best regards,
Tianjia