From 0ad95472bf169a3501991f8f33f5147f792a8116 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Wed, 23 Sep 2015 15:49:29 +0300 Subject: 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 Cc: Signed-off-by: J. Bruce Fields --- fs/lockd/mon.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) (limited to 'fs/lockd/mon.c') diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c index 47a32b6d9b90..6c05cd17e520 100644 --- a/fs/lockd/mon.c +++ b/fs/lockd/mon.c @@ -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", -- cgit v1.2.3