lockd: create NSM handles per net namespace

Commit cb7323fffa85 ("lockd: create and use per-net NSM
 RPC clients on MON/UNMON requests") introduced per-net
NSM RPC clients. Unfortunately this doesn't make any sense
without per-net nsm_handle.

E.g. the following scenario could happen
Two hosts (X and Y) in different namespaces (A and B) share
the same nsm struct.

1. nsm_monitor(host_X) called => NSM rpc client created,
	nsm->sm_monitored bit set.
2. nsm_mointor(host-Y) called => nsm->sm_monitored already set,
	we just exit. Thus in namespace B ln->nsm_clnt == NULL.
3. host X destroyed => nsm->sm_count decremented to 1
4. host Y destroyed => nsm_unmonitor() => nsm_mon_unmon() => NULL-ptr
	dereference of *ln->nsm_clnt

So this could be fixed by making per-net nsm_handles list,
instead of global. Thus different net namespaces will not be able
share the same nsm_handle.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index 969d589c848d..b5f3c3ab0d5f 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -116,7 +116,7 @@ static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
 		atomic_inc(&nsm->sm_count);
 	else {
 		host = NULL;
-		nsm = nsm_get_handle(ni->sap, ni->salen,
+		nsm = nsm_get_handle(ni->net, ni->sap, ni->salen,
 					ni->hostname, ni->hostname_len);
 		if (unlikely(nsm == NULL)) {
 			dprintk("lockd: %s failed; no nsm handle\n",
@@ -534,17 +534,18 @@ static struct nlm_host *next_host_state(struct hlist_head *cache,
 
 /**
  * nlm_host_rebooted - Release all resources held by rebooted host
+ * @net:  network namespace
  * @info: pointer to decoded results of NLM_SM_NOTIFY call
  *
  * We were notified that the specified host has rebooted.  Release
  * all resources held by that peer.
  */
-void nlm_host_rebooted(const struct nlm_reboot *info)
+void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info)
 {
 	struct nsm_handle *nsm;
 	struct nlm_host	*host;
 
-	nsm = nsm_reboot_lookup(info);
+	nsm = nsm_reboot_lookup(net, info);
 	if (unlikely(nsm == NULL))
 		return;