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From: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To: "tcs_kernel(腾讯云内核开发者)" <tcs_kernel@tencent.com>
Cc: Sam Ravnborg <sam@ravnborg.org>,
	"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
	"yepeilin.cs@gmail.com" <yepeilin.cs@gmail.com>,
	"penguin-kernel@I-love.SAKURA.ne.jp" 
	<penguin-kernel@i-love.sakura.ne.jp>,
	"tzimmermann@suse.de" <tzimmermann@suse.de>,
	"george.kennedy@oracle.com" <george.kennedy@oracle.com>,
	"ducheng2@gmail.com" <ducheng2@gmail.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Internet]Re: [PATCH] fbcon: Out-Of-Bounds write in sys_imageblit, add range check
Date: Tue, 27 Jul 2021 07:35:28 +0200	[thread overview]
Message-ID: <YP+bINav7znIU6xF@kroah.com> (raw)
In-Reply-To: <28F2D8E8-B519-40F6-B6CD-98A0FAD67CD7@tencent.com>

On Tue, Jul 27, 2021 at 01:53:13AM +0000, tcs_kernel(腾讯云内核开发者) wrote:
> yres and vyres can be controlled by user mode paramaters, and cause p->vrows to become a negative value. While this value be passed to real_y function, the ypos will be out of screen range.
> This is an out-of-bounds write bug.
> I think updatescrollmode is the right place to validate values supplied by a user ioctl, because only here makes --operation,and 0 is a legal value before that.

Please wrap your changelog text.

> 
> Signed-off-by: Tencent Cloud System tcs_kernel@tencent.com

That is not the name of a person :(

And the format isn't correct, so there's nothing we can do with this
patch, and the patch itself is corrupted and could not be applied :(

Also, what about checking these values earlier?  How can the value be 0
earlier and be acceptable?  Putting bounds on the user-provided values
would be much easier, right?

thanks,

greg k-h

      reply	other threads:[~2021-07-27  5:35 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 11:32 tcs_kernel(腾讯云内核开发者)
2021-07-26 13:00 ` gregkh
     [not found] ` <YP68cQ4WVVusCv0N@ravnborg.org>
2021-07-27  1:53   ` [Internet]Re: " tcs_kernel(腾讯云内核开发者)
2021-07-27  5:35     ` gregkh [this message]

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