From: Jiri Slaby <jslaby@suse.cz>
To: Gen Zhang <blackgod016574@gmail.com>,
dgilbert@interlog.com, jejb@linux.ibm.com,
martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sg: fix a double-fetch bug in sg_write()
Date: Wed, 5 Jun 2019 08:41:11 +0200 [thread overview]
Message-ID: <38bbd54f-d85b-e529-36ad-5c1809bb435f@suse.cz> (raw)
In-Reply-To: <20190531012704.GA4541@zhanggen-UX430UQ>
On 31. 05. 19, 3:27, Gen Zhang wrote:
> In sg_write(), the opcode of the command is fetched the first time from
> the userspace by __get_user(). Then the whole command, the opcode
> included, is fetched again from userspace by __copy_from_user().
> However, a malicious user can change the opcode between the two fetches.
> This can cause inconsistent data and potential errors as cmnd is used in
> the following codes.
>
> Thus we should check opcode between the two fetches to prevent this.
>
> Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> ---
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index d3f1531..a2971b8 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -694,6 +694,8 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
> hp->flags = input_size; /* structure abuse ... */
> hp->pack_id = old_hdr.pack_id;
> hp->usr_ptr = NULL;
> + if (opcode != cmnd[0])
> + return -EINVAL;
> if (__copy_from_user(cmnd, buf, cmd_size))
> return -EFAULT;
You are sending the same patches like a broken machine. Please STOP this
and give people some time to actually review your patches! (Don't expect
replies in days.)
I already commented on this apparently broken one earlier...
thanks,
--
js
suse labs
next prev parent reply other threads:[~2019-06-05 6:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 1:27 [PATCH] sg: fix a double-fetch bug in sg_write() Gen Zhang
2019-06-05 6:41 ` Jiri Slaby [this message]
2019-06-05 15:35 ` Gen Zhang
2019-06-06 5:01 ` Jiri Slaby
2019-06-06 7:43 ` Gen Zhang
-- strict thread matches above, loose matches on Subject: below --
2019-05-27 1:03 Gen Zhang
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