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ipvs: changes related to service usecnt 

Change the usage of svc usecnt during command execution:

- we check if svc is registered but we do not need to hold usecnt
reference while under __ip_vs_mutex, only the packet handling needs
it during scheduling

- change __ip_vs_service_get to __ip_vs_service_find and
__ip_vs_svc_fwm_get to __ip_vs_svc_fwm_find because now caller
will increase svc->usecnt

- put common code that calls update_service in __ip_vs_update_dest

- put common code in ip_vs_unlink_service() and use it to unregister
the service

- add comment that svc should not be accessed after ip_vs_del_service
anymore

- all IP_VS_WAIT_WHILE calls are now unified: usecnt > 0

- Properly log the app ports

	As result, some problems are fixed:

- possible use-after-free of svc in ip_vs_genl_set_cmd after
ip_vs_del_service because our usecnt reference does not guarantee that
svc is not freed on refcnt==0, eg. when no dests are moved to trash

- possible usecnt leak in do_ip_vs_set_ctl after ip_vs_del_service
when the service is not freed now, for example, when some
destionations are moved into trash and svc->refcnt remains above 0.
It is harmless because svc is not in hash anymore.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Julian Anastasov 2010-09-21 18:12:30 +02:00 committed by Patrick McHardy
parent 99f07e91be
commit 26c15cfd29
2 changed files with 102 additions and 154 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
net/netfilter/ipvs/ip_vs_app.c
View File

@ -103,8 +103,8 @@ ip_vs_app_inc_new(struct ip_vs_app *app, __u16 proto, __u16 port)
goto out;
list_add(&inc->a_list, &app->incs_list);
IP_VS_DBG(9, "%s application %s:%u registered\n",
pp->name, inc->name, inc->port);
IP_VS_DBG(9, "%s App %s:%u registered\n",
pp->name, inc->name, ntohs(inc->port));
return 0;
@ -130,7 +130,7 @@ ip_vs_app_inc_release(struct ip_vs_app *inc)
pp->unregister_app(inc);
IP_VS_DBG(9, "%s App %s:%u unregistered\n",
pp->name, inc->name, inc->port);
pp->name, inc->name, ntohs(inc->port));
list_del(&inc->a_list);

250
net/netfilter/ipvs/ip_vs_ctl.c
View File

@ -405,7 +405,7 @@ static int ip_vs_svc_unhash(struct ip_vs_service *svc)
* Get service by {proto,addr,port} in the service table.
*/
static inline struct ip_vs_service *
__ip_vs_service_get(int af, __u16 protocol, const union nf_inet_addr *vaddr,
__ip_vs_service_find(int af, __u16 protocol, const union nf_inet_addr *vaddr,
__be16 vport)
{
unsigned hash;
@ -420,7 +420,6 @@ __ip_vs_service_get(int af, __u16 protocol, const union nf_inet_addr *vaddr,
&& (svc->port == vport)
&& (svc->protocol == protocol)) {
/* HIT */
atomic_inc(&svc->usecnt);
return svc;
}
}
@ -433,7 +432,7 @@ __ip_vs_service_get(int af, __u16 protocol, const union nf_inet_addr *vaddr,
* Get service by {fwmark} in the service table.
*/
static inline struct ip_vs_service *
__ip_vs_svc_fwm_get(int af, __u32 fwmark)
__ip_vs_svc_fwm_find(int af, __u32 fwmark)
{
unsigned hash;
struct ip_vs_service *svc;
@ -444,7 +443,6 @@ __ip_vs_svc_fwm_get(int af, __u32 fwmark)
list_for_each_entry(svc, &ip_vs_svc_fwm_table[hash], f_list) {
if (svc->fwmark == fwmark && svc->af == af) {
/* HIT */
atomic_inc(&svc->usecnt);
return svc;
}
}
@ -463,14 +461,14 @@ ip_vs_service_get(int af, __u32 fwmark, __u16 protocol,
/*
* Check the table hashed by fwmark first
*/
if (fwmark && (svc = __ip_vs_svc_fwm_get(af, fwmark)))
if (fwmark && (svc = __ip_vs_svc_fwm_find(af, fwmark)))
goto out;
/*
* Check the table hashed by <protocol,addr,port>
* for "full" addressed entries
*/
svc = __ip_vs_service_get(af, protocol, vaddr, vport);
svc = __ip_vs_service_find(af, protocol, vaddr, vport);
if (svc == NULL
&& protocol == IPPROTO_TCP
@ -480,7 +478,7 @@ ip_vs_service_get(int af, __u32 fwmark, __u16 protocol,
* Check if ftp service entry exists, the packet
* might belong to FTP data connections.
*/
svc = __ip_vs_service_get(af, protocol, vaddr, FTPPORT);
svc = __ip_vs_service_find(af, protocol, vaddr, FTPPORT);
}
if (svc == NULL
@ -488,10 +486,12 @@ ip_vs_service_get(int af, __u32 fwmark, __u16 protocol,
/*
* Check if the catch-all port (port zero) exists
*/
svc = __ip_vs_service_get(af, protocol, vaddr, 0);
svc = __ip_vs_service_find(af, protocol, vaddr, 0);
}
out:
if (svc)
atomic_inc(&svc->usecnt);
read_unlock(&__ip_vs_svc_lock);
IP_VS_DBG_BUF(9, "lookup service: fwm %u %s %s:%u %s\n",
@ -510,14 +510,19 @@ __ip_vs_bind_svc(struct ip_vs_dest *dest, struct ip_vs_service *svc)
dest->svc = svc;
}
static inline void
static void
__ip_vs_unbind_svc(struct ip_vs_dest *dest)
{
struct ip_vs_service *svc = dest->svc;
dest->svc = NULL;
if (atomic_dec_and_test(&svc->refcnt))
if (atomic_dec_and_test(&svc->refcnt)) {
IP_VS_DBG_BUF(3, "Removing service %u/%s:%u usecnt=%d\n",
svc->fwmark,
IP_VS_DBG_ADDR(svc->af, &svc->addr),
ntohs(svc->port), atomic_read(&svc->usecnt));
kfree(svc);
}
}
@ -762,8 +767,8 @@ ip_vs_zero_stats(struct ip_vs_stats *stats)
* Update a destination in the given service
*/
static void
__ip_vs_update_dest(struct ip_vs_service *svc,
struct ip_vs_dest *dest, struct ip_vs_dest_user_kern *udest)
__ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
struct ip_vs_dest_user_kern *udest, int add)
{
int conn_flags;
@ -818,6 +823,25 @@ __ip_vs_update_dest(struct ip_vs_service *svc,
dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
dest->u_threshold = udest->u_threshold;
dest->l_threshold = udest->l_threshold;
if (add)
ip_vs_new_estimator(&dest->stats);
write_lock_bh(&__ip_vs_svc_lock);
/* Wait until all other svc users go away */
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
if (add) {
list_add(&dest->n_list, &svc->destinations);
svc->num_dests++;
}
/* call the update_service, because server weight may be changed */
if (svc->scheduler->update_service)
svc->scheduler->update_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
}
@ -865,13 +889,12 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest,
atomic_set(&dest->activeconns, 0);
atomic_set(&dest->inactconns, 0);
atomic_set(&dest->persistconns, 0);
atomic_set(&dest->refcnt, 0);
atomic_set(&dest->refcnt, 1);
INIT_LIST_HEAD(&dest->d_list);
spin_lock_init(&dest->dst_lock);
spin_lock_init(&dest->stats.lock);
__ip_vs_update_dest(svc, dest, udest);
ip_vs_new_estimator(&dest->stats);
__ip_vs_update_dest(svc, dest, udest, 1);
*dest_p = dest;
@ -931,65 +954,22 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
IP_VS_DBG_ADDR(svc->af, &dest->vaddr),
ntohs(dest->vport));
__ip_vs_update_dest(svc, dest, udest);
/*
* Get the destination from the trash
*/
list_del(&dest->n_list);
ip_vs_new_estimator(&dest->stats);
write_lock_bh(&__ip_vs_svc_lock);
__ip_vs_update_dest(svc, dest, udest, 1);
ret = 0;
} else {
/*
* Wait until all other svc users go away.
* Allocate and initialize the dest structure
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
list_add(&dest->n_list, &svc->destinations);
svc->num_dests++;
/* call the update_service function of its scheduler */
if (svc->scheduler->update_service)
svc->scheduler->update_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
return 0;
ret = ip_vs_new_dest(svc, udest, &dest);
}
/*
* Allocate and initialize the dest structure
*/
ret = ip_vs_new_dest(svc, udest, &dest);
if (ret) {
return ret;
}
/*
* Add the dest entry into the list
*/
atomic_inc(&dest->refcnt);
write_lock_bh(&__ip_vs_svc_lock);
/*
* Wait until all other svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
list_add(&dest->n_list, &svc->destinations);
svc->num_dests++;
/* call the update_service function of its scheduler */
if (svc->scheduler->update_service)
svc->scheduler->update_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
LeaveFunction(2);
return 0;
return ret;
}
@ -1028,19 +1008,7 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
return -ENOENT;
}
__ip_vs_update_dest(svc, dest, udest);
write_lock_bh(&__ip_vs_svc_lock);
/* Wait until all other svc users go away */
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
/* call the update_service, because server weight may be changed */
if (svc->scheduler->update_service)
svc->scheduler->update_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
__ip_vs_update_dest(svc, dest, udest, 0);
LeaveFunction(2);
return 0;
@ -1067,6 +1035,10 @@ static void __ip_vs_del_dest(struct ip_vs_dest *dest)
* the destination into the trash.
*/
if (atomic_dec_and_test(&dest->refcnt)) {
IP_VS_DBG_BUF(3, "Removing destination %u/%s:%u\n",
dest->vfwmark,
IP_VS_DBG_ADDR(dest->af, &dest->addr),
ntohs(dest->port));
ip_vs_dst_reset(dest);
/* simply decrease svc->refcnt here, let the caller check
and release the service if nobody refers to it.
@ -1133,7 +1105,7 @@ ip_vs_del_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
/*
* Wait until all other svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
/*
* Unlink dest from the service
@ -1190,7 +1162,7 @@ ip_vs_add_service(struct ip_vs_service_user_kern *u,
}
/* I'm the first user of the service */
atomic_set(&svc->usecnt, 1);
atomic_set(&svc->usecnt, 0);
atomic_set(&svc->refcnt, 0);
svc->af = u->af;
@ -1284,7 +1256,7 @@ ip_vs_edit_service(struct ip_vs_service *svc, struct ip_vs_service_user_kern *u)
/*
* Wait until all other svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
/*
* Set the flags and timeout value
@ -1383,21 +1355,23 @@ static void __ip_vs_del_service(struct ip_vs_service *svc)
/*
* Free the service if nobody refers to it
*/
if (atomic_read(&svc->refcnt) == 0)
if (atomic_read(&svc->refcnt) == 0) {
IP_VS_DBG_BUF(3, "Removing service %u/%s:%u usecnt=%d\n",
svc->fwmark,
IP_VS_DBG_ADDR(svc->af, &svc->addr),
ntohs(svc->port), atomic_read(&svc->usecnt));
kfree(svc);
}
/* decrease the module use count */
ip_vs_use_count_dec();
}
/*
* Delete a service from the service list
* Unlink a service from list and try to delete it if its refcnt reached 0
*/
static int ip_vs_del_service(struct ip_vs_service *svc)
static void ip_vs_unlink_service(struct ip_vs_service *svc)
{
if (svc == NULL)
return -EEXIST;
/*
* Unhash it from the service table
*/
@ -1408,11 +1382,21 @@ static int ip_vs_del_service(struct ip_vs_service *svc)
/*
* Wait until all the svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 1);
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
__ip_vs_del_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
}
/*
* Delete a service from the service list
*/
static int ip_vs_del_service(struct ip_vs_service *svc)
{
if (svc == NULL)
return -EEXIST;
ip_vs_unlink_service(svc);
return 0;
}
@ -1431,14 +1415,7 @@ static int ip_vs_flush(void)
*/
for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
list_for_each_entry_safe(svc, nxt, &ip_vs_svc_table[idx], s_list) {
write_lock_bh(&__ip_vs_svc_lock);
ip_vs_svc_unhash(svc);
/*
* Wait until all the svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
__ip_vs_del_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
ip_vs_unlink_service(svc);
}
}
@ -1448,14 +1425,7 @@ static int ip_vs_flush(void)
for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
list_for_each_entry_safe(svc, nxt,
&ip_vs_svc_fwm_table[idx], f_list) {
write_lock_bh(&__ip_vs_svc_lock);
ip_vs_svc_unhash(svc);
/*
* Wait until all the svc users go away.
*/
IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);
__ip_vs_del_service(svc);
write_unlock_bh(&__ip_vs_svc_lock);
ip_vs_unlink_service(svc);
}
}
@ -2168,15 +2138,15 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
/* Lookup the exact service by <protocol, addr, port> or fwmark */
if (usvc.fwmark == 0)
svc = __ip_vs_service_get(usvc.af, usvc.protocol,
&usvc.addr, usvc.port);
svc = __ip_vs_service_find(usvc.af, usvc.protocol,
&usvc.addr, usvc.port);
else
svc = __ip_vs_svc_fwm_get(usvc.af, usvc.fwmark);
svc = __ip_vs_svc_fwm_find(usvc.af, usvc.fwmark);
if (cmd != IP_VS_SO_SET_ADD
&& (svc == NULL || svc->protocol != usvc.protocol)) {
ret = -ESRCH;
goto out_drop_service;
goto out_unlock;
}
switch (cmd) {
@ -2210,10 +2180,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
ret = -EINVAL;
}
out_drop_service:
if (svc)
ip_vs_service_put(svc);
out_unlock:
mutex_unlock(&__ip_vs_mutex);
out_dec:
@ -2306,10 +2272,10 @@ __ip_vs_get_dest_entries(const struct ip_vs_get_dests *get,
int ret = 0;
if (get->fwmark)
svc = __ip_vs_svc_fwm_get(AF_INET, get->fwmark);
svc = __ip_vs_svc_fwm_find(AF_INET, get->fwmark);
else
svc = __ip_vs_service_get(AF_INET, get->protocol, &addr,
get->port);
svc = __ip_vs_service_find(AF_INET, get->protocol, &addr,
get->port);
if (svc) {
int count = 0;
@ -2337,7 +2303,6 @@ __ip_vs_get_dest_entries(const struct ip_vs_get_dests *get,
}
count++;
}
ip_vs_service_put(svc);
} else
ret = -ESRCH;
return ret;
@ -2458,15 +2423,14 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
entry = (struct ip_vs_service_entry *)arg;
addr.ip = entry->addr;
if (entry->fwmark)
svc = __ip_vs_svc_fwm_get(AF_INET, entry->fwmark);
svc = __ip_vs_svc_fwm_find(AF_INET, entry->fwmark);
else
svc = __ip_vs_service_get(AF_INET, entry->protocol,
&addr, entry->port);
svc = __ip_vs_service_find(AF_INET, entry->protocol,
&addr, entry->port);
if (svc) {
ip_vs_copy_service(entry, svc);
if (copy_to_user(user, entry, sizeof(*entry)) != 0)
ret = -EFAULT;
ip_vs_service_put(svc);
} else
ret = -ESRCH;
}
@ -2733,10 +2697,12 @@ nla_put_failure:
}
static int ip_vs_genl_parse_service(struct ip_vs_service_user_kern *usvc,
struct nlattr *nla, int full_entry)
struct nlattr *nla, int full_entry,
struct ip_vs_service **ret_svc)
{
struct nlattr *attrs[IPVS_SVC_ATTR_MAX + 1];
struct nlattr *nla_af, *nla_port, *nla_fwmark, *nla_protocol, *nla_addr;
struct ip_vs_service *svc;
/* Parse mandatory identifying service fields first */
if (nla == NULL ||
@ -2772,12 +2738,18 @@ static int ip_vs_genl_parse_service(struct ip_vs_service_user_kern *usvc,
usvc->fwmark = 0;
}
if (usvc->fwmark)
svc = __ip_vs_svc_fwm_find(usvc->af, usvc->fwmark);
else
svc = __ip_vs_service_find(usvc->af, usvc->protocol,
&usvc->addr, usvc->port);
*ret_svc = svc;
/* If a full entry was requested, check for the additional fields */
if (full_entry) {
struct nlattr *nla_sched, *nla_flags, *nla_timeout,
*nla_netmask;
struct ip_vs_flags flags;
struct ip_vs_service *svc;
nla_sched = attrs[IPVS_SVC_ATTR_SCHED_NAME];
nla_flags = attrs[IPVS_SVC_ATTR_FLAGS];
@ -2790,16 +2762,8 @@ static int ip_vs_genl_parse_service(struct ip_vs_service_user_kern *usvc,
nla_memcpy(&flags, nla_flags, sizeof(flags));
/* prefill flags from service if it already exists */
if (usvc->fwmark)
svc = __ip_vs_svc_fwm_get(usvc->af, usvc->fwmark);
else
svc = __ip_vs_service_get(usvc->af, usvc->protocol,
&usvc->addr, usvc->port);
if (svc) {
if (svc)
usvc->flags = svc->flags;
ip_vs_service_put(svc);
} else
usvc->flags = 0;
/* set new flags from userland */
usvc->flags = (usvc->flags & ~flags.mask) |
@ -2815,17 +2779,11 @@ static int ip_vs_genl_parse_service(struct ip_vs_service_user_kern *usvc,
static struct ip_vs_service *ip_vs_genl_find_service(struct nlattr *nla)
{
struct ip_vs_service_user_kern usvc;
struct ip_vs_service *svc;
int ret;
ret = ip_vs_genl_parse_service(&usvc, nla, 0);
if (ret)
return ERR_PTR(ret);
if (usvc.fwmark)
return __ip_vs_svc_fwm_get(usvc.af, usvc.fwmark);
else
return __ip_vs_service_get(usvc.af, usvc.protocol,
&usvc.addr, usvc.port);
ret = ip_vs_genl_parse_service(&usvc, nla, 0, &svc);
return ret ? ERR_PTR(ret) : svc;
}
static int ip_vs_genl_fill_dest(struct sk_buff *skb, struct ip_vs_dest *dest)
@ -2916,7 +2874,6 @@ static int ip_vs_genl_dump_dests(struct sk_buff *skb,
nla_put_failure:
cb->args[0] = idx;
ip_vs_service_put(svc);
out_err:
mutex_unlock(&__ip_vs_mutex);
@ -3129,17 +3086,10 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
ret = ip_vs_genl_parse_service(&usvc,
info->attrs[IPVS_CMD_ATTR_SERVICE],
need_full_svc);
need_full_svc, &svc);
if (ret)
goto out;
/* Lookup the exact service by <protocol, addr, port> or fwmark */
if (usvc.fwmark == 0)
svc = __ip_vs_service_get(usvc.af, usvc.protocol,
&usvc.addr, usvc.port);
else
svc = __ip_vs_svc_fwm_get(usvc.af, usvc.fwmark);
/* Unless we're adding a new service, the service must already exist */
if ((cmd != IPVS_CMD_NEW_SERVICE) && (svc == NULL)) {
ret = -ESRCH;
@ -3173,6 +3123,7 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
break;
case IPVS_CMD_DEL_SERVICE:
ret = ip_vs_del_service(svc);
/* do not use svc, it can be freed */
break;
case IPVS_CMD_NEW_DEST:
ret = ip_vs_add_dest(svc, &udest);
@ -3191,8 +3142,6 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
}
out:
if (svc)
ip_vs_service_put(svc);
mutex_unlock(&__ip_vs_mutex);
return ret;
@ -3238,7 +3187,6 @@ static int ip_vs_genl_get_cmd(struct sk_buff *skb, struct genl_info *info)
goto out_err;
} else if (svc) {
ret = ip_vs_genl_fill_service(msg, svc);
ip_vs_service_put(svc);
if (ret)
goto nla_put_failure;
} else {