linux-arm-msm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Manivannan Sadhasivam <mani@kernel.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: qrtr: Avoid potential use after free in MHI send
Date: Thu, 22 Apr 2021 09:56:04 +0530	[thread overview]
Message-ID: <20210422042604.GB14470@work> (raw)
In-Reply-To: <20210421174007.2954194-1-bjorn.andersson@linaro.org>

On Wed, Apr 21, 2021 at 10:40:07AM -0700, Bjorn Andersson wrote:
> It is possible that the MHI ul_callback will be invoked immediately
> following the queueing of the skb for transmission, leading to the
> callback decrementing the refcount of the associated sk and freeing the
> skb.
> 
> As such the dereference of skb and the increment of the sk refcount must
> happen before the skb is queued, to avoid the skb to be used after free
> and potentially the sk to drop its last refcount..
> 
> Fixes: 6e728f321393 ("net: qrtr: Add MHI transport layer")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> ---
>  net/qrtr/mhi.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
> index 2bf2b1943e61..fa611678af05 100644
> --- a/net/qrtr/mhi.c
> +++ b/net/qrtr/mhi.c
> @@ -50,6 +50,9 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
>  	struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, ep);
>  	int rc;
>  
> +	if (skb->sk)
> +		sock_hold(skb->sk);
> +
>  	rc = skb_linearize(skb);
>  	if (rc)
>  		goto free_skb;
> @@ -59,12 +62,11 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
>  	if (rc)
>  		goto free_skb;
>  
> -	if (skb->sk)
> -		sock_hold(skb->sk);
> -
>  	return rc;
>  
>  free_skb:
> +	if (skb->sk)
> +		sock_put(skb->sk);
>  	kfree_skb(skb);
>  
>  	return rc;
> -- 
> 2.29.2
> 

  parent reply	other threads:[~2021-04-22  4:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-21 17:40 Bjorn Andersson
2021-04-21 18:10 ` patchwork-bot+netdevbpf
2021-04-22  4:26 ` Manivannan Sadhasivam [this message]
2021-05-26 19:03 ` patchwork-bot+linux-arm-msm

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=20210422042604.GB14470@work \
    --to=mani@kernel.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=davem@davemloft.net \
    --cc=kuba@kernel.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --subject='Re: [PATCH] net: qrtr: Avoid potential use after free in MHI send' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).