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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, Dai Ngo <Dai.Ngo@oracle.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.14 054/162] NLM: Fix svcxdr_encode_owner()
Date:   Mon, 27 Sep 2021 19:01:40 +0200
Message-Id: <20210927170235.363903954@linuxfoundation.org>
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From: Chuck Lever <chuck.lever@oracle.com>

[ Upstream commit 89c485c7a3ecbc2ebd568f9c9c2edf3a8cf7485b ]

Dai Ngo reports that, since the XDR overhaul, the NLM server crashes
when the TEST procedure wants to return NLM_DENIED. There is a bug
in svcxdr_encode_owner() that none of our standard test cases found.

Replace the open-coded function with a call to an appropriate
pre-fabricated XDR helper.

Reported-by: Dai Ngo <Dai.Ngo@oracle.com>
Fixes: a6a63ca5652e ("lockd: Common NLM XDR helpers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/lockd/svcxdr.h | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/fs/lockd/svcxdr.h b/fs/lockd/svcxdr.h
index c69a0bb76c94..4f1a451da5ba 100644
--- a/fs/lockd/svcxdr.h
+++ b/fs/lockd/svcxdr.h
@@ -134,18 +134,9 @@ svcxdr_decode_owner(struct xdr_stream *xdr, struct xdr_netobj *obj)
 static inline bool
 svcxdr_encode_owner(struct xdr_stream *xdr, const struct xdr_netobj *obj)
 {
-	unsigned int quadlen = XDR_QUADLEN(obj->len);
-	__be32 *p;
-
-	if (xdr_stream_encode_u32(xdr, obj->len) < 0)
-		return false;
-	p = xdr_reserve_space(xdr, obj->len);
-	if (!p)
+	if (obj->len > XDR_MAX_NETOBJ)
 		return false;
-	p[quadlen - 1] = 0;	/* XDR pad */
-	memcpy(p, obj->data, obj->len);
-
-	return true;
+	return xdr_stream_encode_opaque(xdr, obj->data, obj->len) > 0;
 }
 
 #endif /* _LOCKD_SVCXDR_H_ */
-- 
2.33.0