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Subject: Re: [PATCH -next] mtd/ftl: Fix uaf in ftl_remove_dev()
To:     <miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>,
        <cuigaosheng1@huawei.com>
CC:     <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <gongruiqi1@huawei.com>, <wangweiyang2@huawei.com>
References: <20220715071119.2321463-1-cuigaosheng1@huawei.com>
From:   cuigaosheng <cuigaosheng1@huawei.com>
Message-ID: <a2b4dccd-0942-69ff-39ac-a9313f41fed1@huawei.com>
Date:   Thu, 18 Aug 2022 09:32:13 +0800
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PING

?? 2022/7/15 15:11, Gaosheng Cui д??:
> del_mtd_blktrans_dev will reclaim the resources of mtd_blktrans_dev,
> and call kfree(dev) in blktrans_dev_put to release the memory of
> mtd_blktrans_dev, so when ftl_freepart reclaims the memory of other
> member pointers of the partition_t, it will trigger the uaf problem,
> Fix it by moving ftl_freepart in front of del_mtd_blktrans_dev.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> ---
>   drivers/mtd/ftl.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c
> index 200271bdc7aa..bec56070039d 100644
> --- a/drivers/mtd/ftl.c
> +++ b/drivers/mtd/ftl.c
> @@ -1039,8 +1039,12 @@ static void ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
>   
>   static void ftl_remove_dev(struct mtd_blktrans_dev *dev)
>   {
> +	struct partition_t *partition;
> +
> +	partition = container_of(dev, struct partition_t, mbd);
> +
> +	ftl_freepart(partition);
>   	del_mtd_blktrans_dev(dev);
> -	ftl_freepart((partition_t *)dev);
>   }
>   
>   static struct mtd_blktrans_ops ftl_tr = {