Date:   Tue, 14 Feb 2023 10:47:41 +0100 (CET)
From:   Richard Weinberger <richard@nod.at>
To:     harshit m mogalapalli <harshit.m.mogalapalli@oracle.com>
Cc:     harshit m mogalapalli <harshit.m.mogalapalli@gmail.com>,
        error27@gmail.com, hch <hch@lst.de>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-mtd <linux-mtd@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Message-ID: <2138680093.127537.1676368061456.JavaMail.zimbra@nod.at>
In-Reply-To: <20230214093801.1267044-1-harshit.m.mogalapalli@oracle.com>
References: <20230214093801.1267044-1-harshit.m.mogalapalli@oracle.com>
Subject: Re: [PATCH linux-next] ubi: block: Fix a possible use-after-free
 bug in ubiblock_create()
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
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Thread-Topic: block: Fix a possible use-after-free bug in ubiblock_create()
Thread-Index: iOg5GBWw/6+vOMMkTA/Bpi1ap7bSZw==
Precedence: bulk

----- Ursprüngliche Mail -----
> Von: "harshit m mogalapalli" <harshit.m.mogalapalli@oracle.com>
> Smatch warns:
>	drivers/mtd/ubi/block.c:438 ubiblock_create()
>	warn: '&dev->list' not removed from list
> 
> 'dev' is freed in 'out_free_dev:, but it is still on the list.
> 
> To fix this, delete the list item before freeing.
> 
> Fixes: 91cc8fbcc8c7 ("ubi: block: set BLK_MQ_F_BLOCKING")
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
> ---
> Found by static analysis(smatch). Only Compile tested.
> ---
> drivers/mtd/ubi/block.c | 1 +
> 1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
> index f5d036203fe7..763704c8d05c 100644
> --- a/drivers/mtd/ubi/block.c
> +++ b/drivers/mtd/ubi/block.c
> @@ -429,6 +429,7 @@ int ubiblock_create(struct ubi_volume_info *vi)
> 	return 0;
> 
> out_remove_minor:
> +	list_del(&dev->list);
> 	idr_remove(&ubiblock_minor_idr, gd->first_minor);
> out_cleanup_disk:
> 	put_disk(dev->gd);

Good catch!

Thanks,
//richard