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Date:   Mon, 26 Jul 2021 08:48:10 +0200
From:   Corentin Labbe <clabbe.montjoie@gmail.com>
To:     Dongliang Mu <mudongliangabcd@gmail.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Maxime Ripard <mripard@kernel.org>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Eric Biggers <ebiggers@google.com>,
        Colin Ian King <colin.king@canonical.com>,
        Xiang Chen <chenxiang66@hisilicon.com>,
        dan.carpenter@oracle.com, linux-crypto@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] crypto: sun8i-ce: fix memory leak and return value of
 sun8i_ce_hash_run
Message-ID: <YP5aqtmAXS4xNtv/@Red>
References: <20210726062801.2078117-1-mudongliangabcd@gmail.com>
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Le Mon, Jul 26, 2021 at 02:27:50PM +0800, Dongliang Mu a ?crit :
> This patch fixes some memory leak caused by dma_mmap_sg/single
> in the error handling code. In addition, it fixes the return value
> when errors related with dma_mmap_sg/single occur.
> 
> Reported-by: Dongliang Mu <mudongliangabcd@gmail.com>
> Fixes: 732b764099f65 ("crypto: sun8i-ce - fix two error path's memory leak")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  .../crypto/allwinner/sun8i-ss/sun8i-ss-hash.c | 37 ++++++++++---------
>  1 file changed, 20 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
> index 3c073eb3db03..7c4ed19f5466 100644
> --- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
> +++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c
> @@ -324,11 +324,11 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
>  	struct sun8i_ss_alg_template *algt;
>  	struct sun8i_ss_dev *ss;
>  	struct scatterlist *sg;
> -	int nr_sgs, err, digestsize;
> +	int j, i, todo, nr_sgs, tmp_err, digestsize;
> +	int err = 0;
>  	unsigned int len;
>  	u64 fill, min_fill, byte_count;
>  	void *pad, *result;
> -	int j, i, todo;
>  	__be64 *bebits;
>  	__le64 *lebits;
>  	dma_addr_t addr_res, addr_pad;
> @@ -368,14 +368,14 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
>  	if (nr_sgs <= 0 || nr_sgs > MAX_SG) {
>  		dev_err(ss->dev, "Invalid sg number %d\n", nr_sgs);
>  		err = -EINVAL;
> -		goto theend;
> +		goto err_result;
>  	}
>  
>  	addr_res = dma_map_single(ss->dev, result, digestsize, DMA_FROM_DEVICE);
>  	if (dma_mapping_error(ss->dev, addr_res)) {
>  		dev_err(ss->dev, "DMA map dest\n");
>  		err = -EINVAL;
> -		goto theend;
> +		goto err_unmap_sg;
>  	}
>  
>  	len = areq->nbytes;
> @@ -390,7 +390,7 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
>  	if (len > 0) {
>  		dev_err(ss->dev, "remaining len %d\n", len);
>  		err = -EINVAL;
> -		goto theend;
> +		goto err_addr_res;
>  	}
>  
>  	byte_count = areq->nbytes;
> @@ -421,27 +421,30 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
>  	}
>  
>  	addr_pad = dma_map_single(ss->dev, pad, j * 4, DMA_TO_DEVICE);
> -	rctx->t_src[i].addr = addr_pad;
> -	rctx->t_src[i].len = j;
> -	rctx->t_dst[i].addr = addr_res;
> -	rctx->t_dst[i].len = digestsize / 4;
>  	if (dma_mapping_error(ss->dev, addr_pad)) {
>  		dev_err(ss->dev, "DMA error on padding SG\n");
>  		err = -EINVAL;
> -		goto theend;
> +		goto err_addr_res;
>  	}
> +	rctx->t_src[i].addr = addr_pad;
> +	rctx->t_src[i].len = j;
> +	rctx->t_dst[i].addr = addr_res;
> +	rctx->t_dst[i].len = digestsize / 4;
>  
> -	err = sun8i_ss_run_hash_task(ss, rctx, crypto_tfm_alg_name(areq->base.tfm));
> +	tmp_err = sun8i_ss_run_hash_task(ss, rctx, crypto_tfm_alg_name(areq->base.tfm));
> +
> +	memcpy(areq->result, result, algt->alg.hash.halg.digestsize);
> +
> +	crypto_finalize_hash_request(engine, breq, tmp_err);
>  
>  	dma_unmap_single(ss->dev, addr_pad, j * 4, DMA_TO_DEVICE);
> +err_addr_res:
> +	dma_unmap_single(ss->dev, addr_res, digestsize, DMA_FROM_DEVICE);
> +err_unmap_sg:
>  	dma_unmap_sg(ss->dev, areq->src, sg_nents(areq->src),
>  		     DMA_TO_DEVICE);
> -	dma_unmap_single(ss->dev, addr_res, digestsize, DMA_FROM_DEVICE);
> -
> -	memcpy(areq->result, result, algt->alg.hash.halg.digestsize);
> -theend:
> +err_result:
>  	kfree(pad);
>  	kfree(result);
> -	crypto_finalize_hash_request(engine, breq, err);
> -	return 0;
> +	return err;
>  }

Hello

This is wrong, you need to always call crypto_finalize_hash_request()

Do you have tested your changes ? Copying results before dma_unmap() is also very wrong, this will lead to random cache fail.

Regards