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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>,
        Christoph Hellwig <hch@lst.de>,
        Anna Schumaker <Anna.Schumaker@Netapp.com>
Subject: [PATCH 3.18 15/29] pnfs/blocklayout: off by one in bl_map_stripe()
Date:   Fri,  7 Sep 2018 23:10:36 +0200
Message-Id: <20180907210910.657928775@linuxfoundation.org>
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3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 0914bb965e38a055e9245637aed117efbe976e91 upstream.

"dev->nr_children" is the number of children which were parsed
successfully in bl_parse_stripe().  It could be all of them and then, in
that case, it is equal to v->stripe.volumes_count.  Either way, the >
should be >= so that we don't go beyond the end of what we're supposed
to.

Fixes: 5c83746a0cf2 ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/blocklayout/dev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -157,7 +157,7 @@ static bool bl_map_stripe(struct pnfs_bl
 	chunk = div_u64(offset, dev->chunk_size);
 	div_u64_rem(chunk, dev->nr_children, &chunk_idx);
 
-	if (chunk_idx > dev->nr_children) {
+	if (chunk_idx >= dev->nr_children) {
 		dprintk("%s: invalid chunk idx %d (%lld/%lld)\n",
 			__func__, chunk_idx, offset, dev->chunk_size);
 		/* error, should not happen */