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From:   Andreas Gruenbacher <agruenba@redhat.com>
Date:   Fri, 26 Aug 2022 15:28:28 +0200
Message-ID: <CAHc6FU4g_6qYsUoFOnfcX5e2=XiZCu76EUy8kFP1AHDW0f6zyQ@mail.gmail.com>
Subject: Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused
 retval to strscpy
To:     Andrew Price <anprice@redhat.com>
Cc:     Wolfram Sang <wsa+renesas@sang-engineering.com>,
        cluster-devel@redhat.com, linux-kernel@vger.kernel.org,
        Bob Peterson <rpeterso@redhat.com>
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Wolfram and Andy,

On Thu, Aug 25, 2022 at 11:33 AM Andrew Price <anprice@redhat.com> wrote:
> On 24/08/2022 21:08, Wolfram Sang wrote:
> > Hi Andy.
> >
> >>> -   strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> >>> -   strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> >>> +   strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> >>> +   strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> >>
> >> Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the size of
> >> the destination, too.
> >>
> >> With that addition, this patch fixes this syzkaller report:
> >>
> >> https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html
> >
> > Linus wrote another summary about strlcpy vs. strscpy use[1]. So, the
> > size argument should be the size of the smaller buffer if the buffers
> > are of different size. GFS2_LOCKNAME_LEN is smaller, so that looks
> > suitable. Shall I resend the patch with the suggested change?
>
> Yes, please. I can't speak for the gfs2 maintainers but I think it would
> be a good plan, as the combination of strscpy and the size change fixes
> a bug.

thanks, I've fixed this in for-next now:

https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git/commit/?h=for-next&id=204c0300c4e99707e9fb6e57840aa1127060e63f

Andreas