[dpdk-stable] [PATCH] vhost: fix possible null pointer dereferencing

[Tiwei Bie]

On Tue, Nov 27, 2018 at 10:23:25AM +0100, Maxime Coquelin wrote:
> If mmap() call fails in vhost_user_set_mem_table, dev->mem
> is set to NULL. If later, qva_to_vva() is called, a segfault
> occurs.
> 
> Fixes: 8f972312b8f4 ("vhost: support vhost-user")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/librte_vhost/vhost_user.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 3ea64eba6..c44fef9cc 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -489,6 +489,9 @@ qva_to_vva(struct virtio_net *dev, uint64_t qva, uint64_t *len)
>  	struct rte_vhost_mem_region *r;
>  	uint32_t i;
>  
> +	if (unlikely(!dev || !dev->mem))
> +		return 0;

Better to also zero *len.

Reviewed-by: Tiwei Bie <tiwei.bie at intel.com>

> +
>  	/* Find the region where the address lives. */
>  	for (i = 0; i < dev->mem->nregions; i++) {
>  		r = &dev->mem->regions[i];
> -- 
> 2.17.2
>