Re: [PATCH][next] crypto: sun8i-ss - Fix memory leak in sun8i_ss_prng_generate()

From: Corentin Labbe <clabbe.montjoie@gmail.com>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
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>,
	linux-crypto@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] crypto: sun8i-ss - Fix memory leak in sun8i_ss_prng_generate()
Date: Fri, 2 Oct 2020 09:11:25 +0200	[thread overview]
Message-ID: <20201002071125.GA15586@Red> (raw)
In-Reply-To: <20200928175945.GA11320@embeddedor>

On Mon, Sep 28, 2020 at 12:59:45PM -0500, Gustavo A. R. Silva wrote:
> Set _err_ to the return error code -EFAULT before jumping to the new
> label err_d, so resources for _d_ can be released before returning
> from function sun8i_ss_prng_generate().
> 
> Addresses-Coverity-ID: 1497459 ("Resource leak")
> Fixes: ac2614d721de ("crypto: sun8i-ss - Add support for the PRNG")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c
> index 08a1473b2145..0573f6289e8b 100644
> --- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c
> +++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-prng.c
> @@ -103,7 +103,8 @@ int sun8i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
>  	dma_iv = dma_map_single(ss->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
>  	if (dma_mapping_error(ss->dev, dma_iv)) {
>  		dev_err(ss->dev, "Cannot DMA MAP IV\n");
> -		return -EFAULT;
> +		err = -EFAULT;
> +		goto err_d;
>  	}
>  
>  	dma_dst = dma_map_single(ss->dev, d, todo, DMA_FROM_DEVICE);
> @@ -160,7 +161,7 @@ int sun8i_ss_prng_generate(struct crypto_rng *tfm, const u8 *src,
>  	dma_unmap_single(ss->dev, dma_dst, todo, DMA_FROM_DEVICE);
>  err_iv:
>  	dma_unmap_single(ss->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);
> -
> +err_d:
>  	if (!err) {
>  		memcpy(dst, d, dlen);
>  		/* Update seed */
> -- 
> 2.27.0
> 

Hello

The label could be better placed just before the kfree.
In error case, there are no need to memzero the not used "d".

But a patch with it, was already sent to the ML.
Anyway if you fix it, you could add "Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>"

Regards