Re: [dpdk-dev] [PATCH v2] vhost/vhost_crypto: do not use possibly NULL Pointers

[Maxime Coquelin <mcoqueli@redhat.com>]

Hi Thierry,

On 5/24/21 11:08 AM, Thierry Herbelot wrote:
> Use vc_req only after it was checked not to be NULL.
> 
> Fixes: 2d962bb736521 ("vhost/crypto: fix possible TOCTOU attack")
> Cc: stable@dpdk.org
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Cc: Chenbo Xia <chenbo.xia@intel.com>
> 
> Signed-off-by: Thierry Herbelot <thierry.herbelot@6wind.com>
> --
> V2: fix copy/paste typo
> ---
>  lib/vhost/vhost_crypto.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/vhost/vhost_crypto.c b/lib/vhost/vhost_crypto.c
> index 6689c52df239..926b5c0bd94a 100644
> --- a/lib/vhost/vhost_crypto.c
> +++ b/lib/vhost/vhost_crypto.c
> @@ -1337,13 +1337,15 @@ vhost_crypto_finalize_one_request(struct rte_crypto_op *op,
>  	struct rte_mbuf *m_src = op->sym->m_src;
>  	struct rte_mbuf *m_dst = op->sym->m_dst;
>  	struct vhost_crypto_data_req *vc_req = rte_mbuf_to_priv(m_src);
> -	struct vhost_virtqueue *vq = vc_req->vq;
> -	uint16_t used_idx = vc_req->desc_idx, desc_idx;
> +	struct vhost_virtqueue *vq;
> +	uint16_t used_idx, desc_idx;
>  
>  	if (unlikely(!vc_req)) {
>  		VC_LOG_ERR("Failed to retrieve vc_req");
>  		return NULL;
>  	}
> +	vq = vc_req->vq;
> +	used_idx = vc_req->desc_idx;
>  
>  	if (old_vq && (vq != old_vq))
>  		return vq;
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime