Thread (12 messages) read the whole thread 12 messages, 3 authors, 2012-09-17

Re: [PATCH 1/3] lockd: use rpc client's cl_nodename for id encoding

From: Chuck Lever <hidden>
Date: 2012-09-14 19:09:05
Also in: lkml

Hi-

On Sep 14, 2012, at 10:25 AM, Stanislav Kinsbursky wrote:
quoted hunk ↗ jump to hunk
Taking hostname from uts namespace if not safe, because this cuold be
performind during umount operation on child reaper death. And in this case
current->nsproxy is NULL already.

Signed-off-by: Stanislav Kinsbursky <redacted>
Cc: <redacted>
---
fs/lockd/mon.c |   14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 7ef14b3..c6186fb 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -426,11 +426,12 @@ static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 * has changed.
 */
-static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp,
+			 char *nodename)
{
	__be32 *p;

-	encode_nsm_string(xdr, utsname()->nodename);
+	encode_nsm_string(xdr, nodename);
	p = xdr_reserve_space(xdr, 4 + 4 + 4);
	*p++ = cpu_to_be32(argp->prog);
	*p++ = cpu_to_be32(argp->vers);
@@ -441,10 +442,11 @@ static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 * The "mon_id" argument specifies the non-private arguments
 * of an NSMPROC_MON or NSMPROC_UNMON call.
 */
-static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp,
+			  char *nodename)
{
	encode_mon_name(xdr, argp);
-	encode_my_id(xdr, argp);
+	encode_my_id(xdr, argp, nodename);
}

/*
@@ -463,14 +465,14 @@ static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
			    const struct nsm_args *argp)
{
-	encode_mon_id(xdr, argp);
+	encode_mon_id(xdr, argp, req->rq_task->tk_client->cl_nodename);
IMO you should get the cl_nodename in nsm_mon_unmon() from clnt->cl_nodename, and pass it in as part of *argp .  The choice of which nodename to use is clearly a decision for an "upper layer" not a choice for the XDR functions.

Long ago I had patches which fixed this layering violation for a very similar purpose as yours, but they were never applied.
	encode_priv(xdr, argp);
}

static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
			      const struct nsm_args *argp)
{
-	encode_mon_id(xdr, argp);
+	encode_mon_id(xdr, argp, req->rq_task->tk_client->cl_nodename);
Ditto.
}

static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,

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-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com



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