All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] vhost: use struct_size and size_add to compute flex array sizes
Date: Mon, 27 Feb 2023 16:53:53 -0500	[thread overview]
Message-ID: <20230227165340-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230227214127.3678392-1-jacob.e.keller@intel.com>

On Mon, Feb 27, 2023 at 01:41:27PM -0800, Jacob Keller wrote:
> The vhost_get_avail_size and vhost_get_used_size functions compute the size
> of structures with flexible array members with an additional 2 bytes if the
> VIRTIO_RING_F_EVENT_IDX feature flag is set. Convert these functions to use
> struct_size() and size_add() instead of coding the calculation by hand.
> 
> This ensures that the calculations will saturate at SIZE_MAX rather than
> overflowing.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: virtualization@lists.linux-foundation.org
> Cc: kvm@vger.kernel.org


Acked-by: Michael S. Tsirkin <mst@redhat.com>

Will merge, thanks!
> ---
> 
> I found this using a coccinelle patch I developed and submitted at [1].
> 
> [1]: https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@intel.com/
> 
>  drivers/vhost/vhost.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f11bdbe4c2c5..43fa626d4e44 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -436,8 +436,7 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
>  	size_t event __maybe_unused =
>  	       vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>  
> -	return sizeof(*vq->avail) +
> -	       sizeof(*vq->avail->ring) * num + event;
> +	return size_add(struct_size(vq->avail, ring, num), event);
>  }
>  
>  static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
> @@ -446,8 +445,7 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
>  	size_t event __maybe_unused =
>  	       vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>  
> -	return sizeof(*vq->used) +
> -	       sizeof(*vq->used->ring) * num + event;
> +	return size_add(struct_size(vq->used, ring, num), event);
>  }
>  
>  static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
> -- 
> 2.39.1.405.gd4c25cc71f83

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: kvm@vger.kernel.org, Jason Wang <jasowang@redhat.com>,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] vhost: use struct_size and size_add to compute flex array sizes
Date: Mon, 27 Feb 2023 16:53:53 -0500	[thread overview]
Message-ID: <20230227165340-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230227214127.3678392-1-jacob.e.keller@intel.com>

On Mon, Feb 27, 2023 at 01:41:27PM -0800, Jacob Keller wrote:
> The vhost_get_avail_size and vhost_get_used_size functions compute the size
> of structures with flexible array members with an additional 2 bytes if the
> VIRTIO_RING_F_EVENT_IDX feature flag is set. Convert these functions to use
> struct_size() and size_add() instead of coding the calculation by hand.
> 
> This ensures that the calculations will saturate at SIZE_MAX rather than
> overflowing.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: virtualization@lists.linux-foundation.org
> Cc: kvm@vger.kernel.org


Acked-by: Michael S. Tsirkin <mst@redhat.com>

Will merge, thanks!
> ---
> 
> I found this using a coccinelle patch I developed and submitted at [1].
> 
> [1]: https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@intel.com/
> 
>  drivers/vhost/vhost.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index f11bdbe4c2c5..43fa626d4e44 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -436,8 +436,7 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
>  	size_t event __maybe_unused =
>  	       vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>  
> -	return sizeof(*vq->avail) +
> -	       sizeof(*vq->avail->ring) * num + event;
> +	return size_add(struct_size(vq->avail, ring, num), event);
>  }
>  
>  static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
> @@ -446,8 +445,7 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
>  	size_t event __maybe_unused =
>  	       vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
>  
> -	return sizeof(*vq->used) +
> -	       sizeof(*vq->used->ring) * num + event;
> +	return size_add(struct_size(vq->used, ring, num), event);
>  }
>  
>  static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
> -- 
> 2.39.1.405.gd4c25cc71f83


  reply	other threads:[~2023-02-27 21:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27 21:41 [PATCH] vhost: use struct_size and size_add to compute flex array sizes Jacob Keller
2023-02-27 21:41 ` Jacob Keller
2023-02-27 21:53 ` Michael S. Tsirkin [this message]
2023-02-27 21:53   ` Michael S. Tsirkin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230227165340-mutt-send-email-mst@kernel.org \
    --to=mst@redhat.com \
    --cc=jacob.e.keller@intel.com \
    --cc=kvm@vger.kernel.org \
    --cc=virtualization@lists.linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.