linux-kernel - Re: [PATCH] vc_screen: don't clobber return value in vcs

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Message-ID: <Y/TMH8Hf6zBrC3yc@kroah.com>
Date:   Tue, 21 Feb 2023 14:50:23 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     George Kennedy <george.kennedy@...cle.com>
Cc:     Thomas Weißschuh <linux@...ssschuh.net>,
        Jiri Slaby <jirislaby@...nel.org>,
        linux-kernel@...r.kernel.org, Randy Dunlap <rdunlap@...radead.org>,
        Storm Dragon <stormdragon2976@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        sfr@...b.auug.org.au, akpm@...ux-foundation.org,
        linux-serial@...r.kernel.org
Subject: Re: [PATCH] vc_screen: don't clobber return value in vcs_read

On Tue, Feb 21, 2023 at 08:30:11AM -0500, George Kennedy wrote:
> 
> 
> On 2/20/2023 11:34 AM, Thomas Weißschuh wrote:
> > +Cc people who were involved in the original thread.
> > 
> > On Mon, Feb 20, 2023 at 12:48:59PM +0100, Jiri Slaby wrote:
> > > On 20. 02. 23, 7:46, linux@...ssschuh.net wrote:
> > > > From: Thomas Weißschuh <linux@...ssschuh.net>
> > > > 
> > > > Commit 226fae124b2d
> > > > ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF")
> > > > moved the call to vcs_vc() into the loop.
> > > > While doing this it also moved the unconditional assignment of
> > > > "ret = -ENXIO".
> > > > This unconditional assignment was valid outside the loop but within it
> > > > it clobbers the actual value of ret.
> > > > 
> > > > To avoid this only assign "ret = -ENXIO" when actually needed.
> > > Not sure -- I cannot find it -- but hasn't George fixed this yet?
> > Indeed there was a proposed fix at
> > https://lore.kernel.org/lkml/1675704844-17228-1-git-send-email-george.kennedy@oracle.com/
> > 
> > Linus had some suggestions so it was not applied as is.
> > 
> > I'm not sure what the current state is.
> > George, do you have something in the pipeline?
> 
> Yes, that is in the pipeline:
> https://lore.kernel.org/lkml/1675774098-17722-1-git-send-email-george.kennedy@oracle.com/
> 
> Linus suggested the fix, which was tested and submitted.
> 
> Jiri commented on the patch, which I believe was directed at Linus as he
> suggested the fix.

And I was waiting for a new version from you based on those comments :(

Can you fix that up and send?

thanks,

greg k-h