Re: [PATCH] aoe: fix the potential use-after-free problem in more places

joeyli
2024-04-30T15:14:59Z

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