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lockd: create NSM handles per net namespace

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Commit cb7323fffa ("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>
This commit is contained in:
Andrey Ryabinin 2015-09-23 15:49:29 +03:00 committed by J. Bruce Fields
parent aaf91ec148
commit 0ad95472bf
7 changed files with 36 additions and 22 deletions
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7
fs/lockd/host.c
View file

@ -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;

36
fs/lockd/mon.c
View file

@ -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",

1
fs/lockd/netns.h
View file

@ -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;

1
fs/lockd/svc.c
View file

@ -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;
}

2
fs/lockd/svc4proc.c
View file

@ -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;
}

2
fs/lockd/svcproc.c
View file

@ -464,7 +464,7 @@ nlmsvc_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;
}

9
include/linux/lockd/lockd.h
View file

@ -235,7 +235,8 @@ void nlm_rebind_host(struct nlm_host *);
struct nlm_host * nlm_get_host(struct nlm_host *);
void nlm_shutdown_hosts(void);
void nlm_shutdown_hosts_net(struct net *net);
void nlm_host_rebooted(const struct nlm_reboot *);
void nlm_host_rebooted(const struct net *net,
const struct nlm_reboot *);
/*
* Host monitoring
@ -243,11 +244,13 @@ void nlm_host_rebooted(const struct nlm_reboot *);
int nsm_monitor(const struct nlm_host *host);
void nsm_unmonitor(const struct nlm_host *host);
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 *nsm_reboot_lookup(const struct nlm_reboot *info);
struct nsm_handle *nsm_reboot_lookup(const struct net *net,
const struct nlm_reboot *info);
void nsm_release(struct nsm_handle *nsm);
/*