[PATCH 4.19 118/243] lockd: fix decoding of TEST results

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: J. Bruce Fields <bfields@xxxxxxxxxx>

[ Upstream commit b8db159239b3f51e2b909859935cc25cb3ff3eed ]

We fail to advance the read pointer when reading the stat.oh field that
identifies the lock-holder in a TEST result.

This turns out not to matter if the server is knfsd, which always
returns a zero-length field.  But other servers (Ganesha is an example)
may not do this.  The result is bad values in fcntl F_GETLK results.

Fix this.

Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/lockd/clnt4xdr.c | 22 ++++++----------------
 fs/lockd/clntxdr.c  | 22 ++++++----------------
 2 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/fs/lockd/clnt4xdr.c b/fs/lockd/clnt4xdr.c
index 00d5ef5f99f73..214a2fa1f1e39 100644
--- a/fs/lockd/clnt4xdr.c
+++ b/fs/lockd/clnt4xdr.c
@@ -128,24 +128,14 @@ static void encode_netobj(struct xdr_stream *xdr,
 static int decode_netobj(struct xdr_stream *xdr,
 			 struct xdr_netobj *obj)
 {
-	u32 length;
-	__be32 *p;
+	ssize_t ret;
 
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(p == NULL))
-		goto out_overflow;
-	length = be32_to_cpup(p++);
-	if (unlikely(length > XDR_MAX_NETOBJ))
-		goto out_size;
-	obj->len = length;
-	obj->data = (u8 *)p;
+	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
+						XDR_MAX_NETOBJ);
+	if (unlikely(ret < 0))
+		return -EIO;
+	obj->len = ret;
 	return 0;
-out_size:
-	dprintk("NFS: returned netobj was too long: %u\n", length);
-	return -EIO;
-out_overflow:
-	print_overflow_msg(__func__, xdr);
-	return -EIO;
 }
 
 /*
diff --git a/fs/lockd/clntxdr.c b/fs/lockd/clntxdr.c
index 2c6176387143c..747b9c8c940ac 100644
--- a/fs/lockd/clntxdr.c
+++ b/fs/lockd/clntxdr.c
@@ -125,24 +125,14 @@ static void encode_netobj(struct xdr_stream *xdr,
 static int decode_netobj(struct xdr_stream *xdr,
 			 struct xdr_netobj *obj)
 {
-	u32 length;
-	__be32 *p;
+	ssize_t ret;
 
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(p == NULL))
-		goto out_overflow;
-	length = be32_to_cpup(p++);
-	if (unlikely(length > XDR_MAX_NETOBJ))
-		goto out_size;
-	obj->len = length;
-	obj->data = (u8 *)p;
+	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
+			XDR_MAX_NETOBJ);
+	if (unlikely(ret < 0))
+		return -EIO;
+	obj->len = ret;
 	return 0;
-out_size:
-	dprintk("NFS: returned netobj was too long: %u\n", length);
-	return -EIO;
-out_overflow:
-	print_overflow_msg(__func__, xdr);
-	return -EIO;
 }
 
 /*
-- 
2.20.1