From: Jeff Layton <jlayton@kernel.org>
To: Chuck Lever <chuck.lever@oracle.com>, linux-nfs@vger.kernel.org
Subject: Re: [PATCH v3 3/6] NFSD: Protect against send buffer overflow in NFSv2 READDIR
Date: Fri, 02 Sep 2022 09:09:01 -0400 [thread overview]
Message-ID: <86bb9bc0a5b9e46c93c9918b7df6708ef7e01830.camel@kernel.org> (raw)
In-Reply-To: <166205940565.1435.7170548905174362083.stgit@manet.1015granger.net>
On Thu, 2022-09-01 at 15:10 -0400, Chuck Lever wrote:
> Restore the previous limit on the @count argument to prevent a
> buffer overflow attack.
>
> Fixes: 53b1119a6e50 ("NFSD: Fix READDIR buffer overflow")
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> fs/nfsd/nfsproc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> index 7381972f1677..ddb1902c0a18 100644
> --- a/fs/nfsd/nfsproc.c
> +++ b/fs/nfsd/nfsproc.c
> @@ -567,12 +567,11 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *rqstp,
> struct xdr_buf *buf = &resp->dirlist;
> struct xdr_stream *xdr = &resp->xdr;
>
> - count = clamp(count, (u32)(XDR_UNIT * 2), svc_max_payload(rqstp));
> -
> memset(buf, 0, sizeof(*buf));
>
> /* Reserve room for the NULL ptr & eof flag (-2 words) */
> - buf->buflen = count - XDR_UNIT * 2;
> + buf->buflen = clamp(count, (u32)(XDR_UNIT * 2), (u32)PAGE_SIZE);
> + buf->buflen -= XDR_UNIT * 2;
> buf->pages = rqstp->rq_next_page;
> rqstp->rq_next_page++;
>
>
>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
next prev parent reply other threads:[~2022-09-02 13:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 19:09 [PATCH v3 0/6] Fixes for server-side xdr_stream overhaul Chuck Lever
2022-09-01 19:09 ` [PATCH v3 1/6] SUNRPC: Fix svcxdr_init_decode's end-of-buffer calculation Chuck Lever
2022-09-01 19:09 ` [PATCH v3 2/6] SUNRPC: Fix svcxdr_init_encode's buflen calculation Chuck Lever
2022-09-01 19:10 ` [PATCH v3 3/6] NFSD: Protect against send buffer overflow in NFSv2 READDIR Chuck Lever
2022-09-02 13:09 ` Jeff Layton [this message]
2022-09-01 19:10 ` [PATCH v3 4/6] NFSD: Protect against send buffer overflow in NFSv3 READDIR Chuck Lever
2022-09-02 13:12 ` Jeff Layton
2022-09-01 19:10 ` [PATCH v3 5/6] NFSD: Protect against send buffer overflow in NFSv2 READ Chuck Lever
2022-09-02 13:14 ` Jeff Layton
2022-09-01 19:10 ` [PATCH v3 6/6] NFSD: Protect against send buffer overflow in NFSv3 READ Chuck Lever
2022-09-02 13:15 ` Jeff Layton
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