From: Benjamin Block <bblock@linux.ibm.com>
To: Qinglang Miao <miaoqinglang@huawei.com>
Cc: Steffen Maier <maier@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] scsi: zfcp: fix use-after-free in zfcp_unit_remove
Date: Wed, 25 Nov 2020 18:06:58 +0100 [thread overview]
Message-ID: <20201125170658.GB8578@t480-pf1aa2c2> (raw)
In-Reply-To: <20201120074854.31754-1-miaoqinglang@huawei.com>
On Fri, Nov 20, 2020 at 03:48:54PM +0800, Qinglang Miao wrote:
> kfree(port) is called in put_device(&port->dev) so that following
> use would cause use-after-free bug.
>
> The former put_device is redundant for device_unregister contains
> put_device already. So just remove it to fix this.
>
> Fixes: 86bdf218a717 ("[SCSI] zfcp: cleanup unit sysfs attribute usage")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
> ---
> drivers/s390/scsi/zfcp_unit.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
> index e67bf7388..664b77853 100644
> --- a/drivers/s390/scsi/zfcp_unit.c
> +++ b/drivers/s390/scsi/zfcp_unit.c
> @@ -255,8 +255,6 @@ int zfcp_unit_remove(struct zfcp_port *port, u64 fcp_lun)
> scsi_device_put(sdev);
> }
>
> - put_device(&unit->dev);
> -
> device_unregister(&unit->dev);
>
> return 0;
Same as in the other mail for `zfcp_sysfs_port_remove_store()`. We
explicitly get a new ref in `_zfcp_unit_find()`, so we also need to put
that away again.
--
Best Regards, Benjamin Block / Linux on IBM Z Kernel Development / IBM Systems
IBM Deutschland Research & Development GmbH / https://www.ibm.com/privacy
Vorsitz. AufsR.: Gregor Pillen / Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: AmtsG Stuttgart, HRB 243294
next prev parent reply other threads:[~2020-11-25 17:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 7:48 [PATCH] scsi: zfcp: fix use-after-free in zfcp_unit_remove Qinglang Miao
2020-11-25 17:06 ` Benjamin Block [this message]
2020-11-26 1:27 ` Qinglang Miao
2020-11-26 8:13 ` Cornelia Huck
2020-11-26 9:42 ` Benjamin Block
2020-11-26 12:07 ` Qinglang Miao
2020-11-26 15:12 ` Benjamin Block
2020-11-27 9:21 ` Steffen Maier
2020-12-01 2:46 ` Qinglang Miao
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