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Date: Tue, 30 Apr 2024 23:14:49 +0800
From: joeyli <jlee@suse.com>
To: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>
Cc: Justin Sanders <justin@coraid.com>, Jens Axboe <axboe@kernel.dk>,
	Pavel Emelianov <xemul@openvz.org>,
	Kirill Korotaev <dev@openvz.org>,
	"David S . Miller" <davem@davemloft.net>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] aoe: fix the potential use-after-free problem in more
 places
Message-ID: <20240430151449.GM26307@linux-l9pv.suse>
References: <20240410134858.6313-1-jlee@suse.com>
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In-Reply-To: <20240410134858.6313-1-jlee@suse.com>
User-Agent: Mutt/1.11.4 (2019-03-13)

Hi Justin, 

On Wed, Apr 10, 2024 at 09:48:58PM +0800, Lee, Chun-Yi wrote:
> From: Chun-Yi Lee <jlee@suse.com>
> 
> For fixing CVE-2023-6270, f98364e92662 patch moved dev_put() from
> aoecmd_cfg_pkts() to tx() to avoid that the tx() runs into use-after-free.
> 
> But Nicolai Stange found more places in aoe have potential use-after-free
> problem with tx(). e.g. revalidate(), aoecmd_ata_rw(), resend(), probe()
> and aoecmd_cfg_rsp(). Those functions also use aoenet_xmit() to push
> packet to tx queue. So they should also use dev_hold() to increase the
> refcnt of skb->dev.
> 
> This patch adds dev_hold() to those functions and also uses dev_put()
> when the skb_clone() returns NULL.
> 
> Link: https://nvd.nist.gov/vuln/detail/CVE-2023-6270
> Fixes: f98364e92662 ("aoe: fix the potential use-after-free problem in
> aoecmd_cfg_pkts")
> Reported-by: Nicolai Stange <nstange@suse.com>
> Signed-off-by: Chun-Yi Lee <jlee@suse.com>

Do you have any suggestion for this patch? or I missed anything?

Thanks a lot!
Joey Lee

> ---
>  drivers/block/aoe/aoecmd.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
> index cc9077b588d7..fcedbad8e3be 100644
> --- a/drivers/block/aoe/aoecmd.c
> +++ b/drivers/block/aoe/aoecmd.c
> @@ -361,6 +361,7 @@ ata_rw_frameinit(struct frame *f)
>  	}
>  
>  	ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
> +	dev_hold(t->ifp->nd);
>  	skb->dev = t->ifp->nd;
>  }
>  
> @@ -401,7 +402,8 @@ aoecmd_ata_rw(struct aoedev *d)
>  		__skb_queue_head_init(&queue);
>  		__skb_queue_tail(&queue, skb);
>  		aoenet_xmit(&queue);
> -	}
> +	} else
> +		dev_put(f->t->ifp->nd);
>  	return 1;
>  }
>  
> @@ -483,10 +485,13 @@ resend(struct aoedev *d, struct frame *f)
>  	memcpy(h->dst, t->addr, sizeof h->dst);
>  	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
>  
> +	dev_hold(t->ifp->nd);
>  	skb->dev = t->ifp->nd;
>  	skb = skb_clone(skb, GFP_ATOMIC);
> -	if (skb == NULL)
> +	if (skb == NULL) {
> +		dev_put(t->ifp->nd);
>  		return;
> +	}
>  	f->sent = ktime_get();
>  	__skb_queue_head_init(&queue);
>  	__skb_queue_tail(&queue, skb);
> @@ -617,7 +622,8 @@ probe(struct aoetgt *t)
>  		__skb_queue_head_init(&queue);
>  		__skb_queue_tail(&queue, skb);
>  		aoenet_xmit(&queue);
> -	}
> +	} else
> +		dev_put(f->t->ifp->nd);
>  }
>  
>  static long
> @@ -1395,6 +1401,7 @@ aoecmd_ata_id(struct aoedev *d)
>  	ah->cmdstat = ATA_CMD_ID_ATA;
>  	ah->lba3 = 0xa0;
>  
> +	dev_hold(t->ifp->nd);
>  	skb->dev = t->ifp->nd;
>  
>  	d->rttavg = RTTAVG_INIT;
> @@ -1404,6 +1411,8 @@ aoecmd_ata_id(struct aoedev *d)
>  	skb = skb_clone(skb, GFP_ATOMIC);
>  	if (skb)
>  		f->sent = ktime_get();
> +	else
> +		dev_put(t->ifp->nd);
>  
>  	return skb;
>  }
> -- 
> 2.35.3