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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>
Subject: [PATCH 4.19 063/116] NFS: fix an incorrect limit in filelayout_decode_layout()
Date:   Mon, 31 May 2021 15:13:59 +0200
Message-Id: <20210531130642.301511141@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

commit 769b01ea68b6c49dc3cde6adf7e53927dacbd3a8 upstream.

The "sizeof(struct nfs_fh)" is two bytes too large and could lead to
memory corruption.  It should be NFS_MAXFHSIZE because that's the size
of the ->data[] buffer.

I reversed the size of the arguments to put the variable on the left.

Fixes: 16b374ca439f ("NFSv4.1: pnfs: filelayout: add driver's LAYOUTGET and GETDEVICEINFO infrastructure")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/nfs/filelayout/filelayout.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -717,7 +717,7 @@ filelayout_decode_layout(struct pnfs_lay
 		if (unlikely(!p))
 			goto out_err;
 		fl->fh_array[i]->size = be32_to_cpup(p++);
-		if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
+		if (fl->fh_array[i]->size > NFS_MAXFHSIZE) {
 			printk(KERN_ERR "NFS: Too big fh %d received %d\n",
 			       i, fl->fh_array[i]->size);
 			goto out_err;