Commit 0ad95472 authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by J. Bruce Fields
Browse files

lockd: create NSM handles per net namespace 



Commit cb7323ff ("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: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent aaf91ec1

fs/lockd/host.c

+4 −3
Original line number Diff line number Diff line
@@ -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;

fs/lockd/mon.c

+22 −14
Original line number Diff line number Diff line
@@ -51,7 +51,6 @@ struct nsm_res { 
};



static const struct rpc_program	nsm_program;

static				LIST_HEAD(nsm_handles);

static				DEFINE_SPINLOCK(nsm_lock);



/*
@@ -264,33 +263,35 @@ void nsm_unmonitor(const struct nlm_host *host) 
	}

}



static struct nsm_handle *nsm_lookup_hostname(const char *hostname,

					      const size_t len)

static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles,

					const char *hostname, const size_t len)

{

	struct nsm_handle *nsm;



	list_for_each_entry(nsm, &nsm_handles, sm_link)

	list_for_each_entry(nsm, nsm_handles, sm_link)

		if (strlen(nsm->sm_name) == len &&

		    memcmp(nsm->sm_name, hostname, len) == 0)

			return nsm;

	return NULL;

}



static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)

static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles,

					const struct sockaddr *sap)

{

	struct nsm_handle *nsm;



	list_for_each_entry(nsm, &nsm_handles, sm_link)

	list_for_each_entry(nsm, nsm_handles, sm_link)

		if (rpc_cmp_addr(nsm_addr(nsm), sap))

			return nsm;

	return NULL;

}



static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)

static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles,

					const struct nsm_private *priv)

{

	struct nsm_handle *nsm;



	list_for_each_entry(nsm, &nsm_handles, sm_link)

	list_for_each_entry(nsm, nsm_handles, sm_link)

		if (memcmp(nsm->sm_priv.data, priv->data,

					sizeof(priv->data)) == 0)

			return nsm;
@@ -353,6 +354,7 @@ static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 


/**

 * nsm_get_handle - Find or create a cached nsm_handle

 * @net: network namespace

 * @sap: pointer to socket address of handle to find

 * @salen: length of socket address

 * @hostname: pointer to C string containing hostname to find
@@ -365,11 +367,13 @@ static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 
 * @hostname cannot be found in the handle cache.  Returns NULL if

 * an error occurs.

 */

struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,

struct nsm_handle *nsm_get_handle(const struct net *net,

				  const struct sockaddr *sap,

				  const size_t salen, const char *hostname,

				  const size_t hostname_len)

{

	struct nsm_handle *cached, *new = NULL;

	struct lockd_net *ln = net_generic(net, lockd_net_id);



	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {

		if (printk_ratelimit()) {
@@ -384,9 +388,10 @@ retry: 
	spin_lock(&nsm_lock);



	if (nsm_use_hostnames && hostname != NULL)

		cached = nsm_lookup_hostname(hostname, hostname_len);

		cached = nsm_lookup_hostname(&ln->nsm_handles,

					hostname, hostname_len);

	else

		cached = nsm_lookup_addr(sap);

		cached = nsm_lookup_addr(&ln->nsm_handles, sap);



	if (cached != NULL) {

		atomic_inc(&cached->sm_count);
@@ -400,7 +405,7 @@ retry: 
	}



	if (new != NULL) {

		list_add(&new->sm_link, &nsm_handles);

		list_add(&new->sm_link, &ln->nsm_handles);

		spin_unlock(&nsm_lock);

		dprintk("lockd: created nsm_handle for %s (%s)\n",

				new->sm_name, new->sm_addrbuf);
@@ -417,19 +422,22 @@ retry: 


/**

 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle

 * @net:  network namespace

 * @info: pointer to NLMPROC_SM_NOTIFY arguments

 *

 * Returns a matching nsm_handle if found in the nsm cache. The returned

 * nsm_handle's reference count is bumped. Otherwise returns NULL if some

 * error occurred.

 */

struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)

struct nsm_handle *nsm_reboot_lookup(const struct net *net,

				const struct nlm_reboot *info)

{

	struct nsm_handle *cached;

	struct lockd_net *ln = net_generic(net, lockd_net_id);



	spin_lock(&nsm_lock);



	cached = nsm_lookup_priv(&info->priv);

	cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv);

	if (unlikely(cached == NULL)) {

		spin_unlock(&nsm_lock);

		dprintk("lockd: never saw rebooted peer '%.*s' before\n",

fs/lockd/netns.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ struct lockd_net { 
	spinlock_t nsm_clnt_lock;

	unsigned int nsm_users;

	struct rpc_clnt *nsm_clnt;

	struct list_head nsm_handles;

};



extern int lockd_net_id;

fs/lockd/svc.c

+1 −0
Original line number Diff line number Diff line
@@ -593,6 +593,7 @@ static int lockd_init_net(struct net *net) 
	INIT_LIST_HEAD(&ln->lockd_manager.list);

	ln->lockd_manager.block_opens = false;

	spin_lock_init(&ln->nsm_clnt_lock);

	INIT_LIST_HEAD(&ln->nsm_handles);

	return 0;

}

fs/lockd/svc4proc.c

+1 −1
Original line number Diff line number Diff line
@@ -421,7 +421,7 @@ nlm4svc_proc_sm_notify(struct svc_rqst *rqstp, struct nlm_reboot *argp, 
		return rpc_system_err;

	}



	nlm_host_rebooted(argp);

	nlm_host_rebooted(SVC_NET(rqstp), argp);

	return rpc_success;

}

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