From: Dan Carpenter <dan.carpenter@oracle.com>
To: Colin King <colin.king@canonical.com>
Cc: Ari Kauppi <ari@synopsys.com>,
"J . Bruce Fields" <bfields@fieldses.org>,
Jeff Layton <jlayton@poochiereds.net>,
linux-nfs@vger.kernel.org, kernel-janitors@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nfsd: avoid out of bounds read on array nfsd4_layout_ops
Date: Tue, 9 May 2017 17:04:14 +0300 [thread overview]
Message-ID: <20170509140414.ycw4z6zsdevbkozm@mwanda> (raw)
In-Reply-To: <20170509133121.26529-1-colin.king@canonical.com>
On Tue, May 09, 2017 at 02:31:21PM +0100, Colin King wrote:
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 1dbf62190bee..c453a1998e00 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1259,7 +1259,8 @@ nfsd4_layout_verify(struct svc_export *exp, unsigned int layout_type)
> return NULL;
> }
>
> - if (layout_type >= 32 || !(exp->ex_layout_types & (1 << layout_type))) {
> + if (layout_type >= LAYOUT_TYPE_MAX ||
> + !(exp->ex_layout_types & (1 << layout_type))) {
The 32 is there to prevent a shift wrapping bug. The bit test prevents
a buffer overflow so this can't actually overflow. But this change
doesn't hurt and is probably cleaner.
exp->ex_layout_types is set in nfsd4_setup_layout_type().
regards,
dan carpenter
next prev parent reply other threads:[~2017-05-09 14:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-09 13:31 Colin King
2017-05-09 14:04 ` Dan Carpenter [this message]
2017-05-09 21:03 ` J . Bruce Fields
2017-05-09 21:14 ` Colin Ian King
2017-05-10 5:24 ` Ari Kauppi
2017-05-09 19:57 ` Christoph Hellwig
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