linux-kernel - [PATCH] SUNRPC: check current nsproxy before set of node name on client creation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 13 Aug 2012 15:21:56 +0400
From:	Stanislav Kinsbursky <skinsbursky@...allels.com>
To:	Trond.Myklebust@...app.com
Cc:	bfields@...ldses.org, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, devel@...nvz.org
Subject: [PATCH] SUNRPC: check current nsproxy before set of node name on
	client creation

When child reaper exits, it can destroy mount namespace it belong to, and if
there are NFS mounts inside, then it will try to umount them. But in this
point current->nsproxy is set to NULL and all namespaces will be destroyed one
by one. I.e. we can't dereference current->nsproxy to obtain uts namespace.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@...allels.com>
---
 net/sunrpc/clnt.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 9a9676e..28ac940 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -279,6 +279,16 @@ void rpc_clients_notifier_unregister(void)
 
 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
 {
+	const char *nodename;
+
+	/*
+	 * We have to protect against dying chilp reaper, which has released
+	 * it's nsproxy already and is trying to destroy mount namespace.
+	 */
+	if (current->nsproxy == NULL)
+		return;
+
+	nodename = utsname()->nodename;
 	clnt->cl_nodelen = strlen(nodename);
 	if (clnt->cl_nodelen > UNX_MAXNODENAME)
 		clnt->cl_nodelen = UNX_MAXNODENAME;
@@ -365,7 +375,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
 	}
 
 	/* save the nodename */
-	rpc_clnt_set_nodename(clnt, utsname()->nodename);
+	rpc_clnt_set_nodename(clnt);
 	rpc_register_client(clnt);
 	return clnt;
 
@@ -524,7 +534,7 @@ rpc_clone_client(struct rpc_clnt *clnt)
 	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 	if (err != 0)
 		goto out_no_path;
-	rpc_clnt_set_nodename(new, utsname()->nodename);
+	rpc_clnt_set_nodename(new);
 	if (new->cl_auth)
 		atomic_inc(&new->cl_auth->au_count);
 	atomic_inc(&clnt->cl_count);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/