[PATCH 4.4 019/193] netfilter: xt_RATEEST: acquire xt_rateest_mutex for hash insert

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Cong Wang 

commit 7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 upstream.

rateest_hash is supposed to be protected by xt_rateest_mutex,
and, as suggested by Eric, lookup and insert should be atomic,
so we should acquire the xt_rateest_mutex once for both.

So introduce a non-locking helper for internal use and keep the
locking one for external.

Reported-by: 
Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target")
Signed-off-by: Cong Wang 
Reviewed-by: Florian Westphal 
Reviewed-by: Eric Dumazet 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman 

---
 net/netfilter/xt_RATEEST.c |   22 +-
 1 file changed, 17 insertions(+), 5 deletions(-)

--- a/net/netfilter/xt_RATEEST.c
+++ b/net/netfilter/xt_RATEEST.c
@@ -40,23 +40,31 @@ static void xt_rateest_hash_insert(struc
hlist_add_head(>list, _hash[h]);
 }
 
-struct xt_rateest *xt_rateest_lookup(const char *name)
+static struct xt_rateest *__xt_rateest_lookup(const char *name)
 {
struct xt_rateest *est;
unsigned int h;
 
h = xt_rateest_hash(name);
-   mutex_lock(_rateest_mutex);
hlist_for_each_entry(est, _hash[h], list) {
if (strcmp(est->name, name) == 0) {
est->refcnt++;
-   mutex_unlock(_rateest_mutex);
return est;
}
}
-   mutex_unlock(_rateest_mutex);
+
return NULL;
 }
+
+struct xt_rateest *xt_rateest_lookup(const char *name)
+{
+   struct xt_rateest *est;
+
+   mutex_lock(_rateest_mutex);
+   est = __xt_rateest_lookup(name);
+   mutex_unlock(_rateest_mutex);
+   return est;
+}
 EXPORT_SYMBOL_GPL(xt_rateest_lookup);
 
 void xt_rateest_put(struct xt_rateest *est)
@@ -104,8 +112,10 @@ static int xt_rateest_tg_checkentry(cons
rnd_inited = true;
}
 
-   est = xt_rateest_lookup(info->name);
+   mutex_lock(_rateest_mutex);
+   est = __xt_rateest_lookup(info->name);
if (est) {
+   mutex_unlock(_rateest_mutex);
/*
 * If estimator parameters are specified, they must match the
 * existing estimator.
@@ -143,11 +153,13 @@ static int xt_rateest_tg_checkentry(cons
 
info->est = est;
xt_rateest_hash_insert(est);
+   mutex_unlock(_rateest_mutex);
return 0;
 
 err2:
kfree(est);
 err1:
+   mutex_unlock(_rateest_mutex);
return ret;
 }
 

[PATCH 4.4 019/193] netfilter: xt_RATEEST: acquire xt_rateest_mutex for hash insert

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Cong Wang 

commit 7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 upstream.

rateest_hash is supposed to be protected by xt_rateest_mutex,
and, as suggested by Eric, lookup and insert should be atomic,
so we should acquire the xt_rateest_mutex once for both.

So introduce a non-locking helper for internal use and keep the
locking one for external.

Reported-by: 
Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target")
Signed-off-by: Cong Wang 
Reviewed-by: Florian Westphal 
Reviewed-by: Eric Dumazet 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman 

---
 net/netfilter/xt_RATEEST.c |   22 +-
 1 file changed, 17 insertions(+), 5 deletions(-)

--- a/net/netfilter/xt_RATEEST.c
+++ b/net/netfilter/xt_RATEEST.c
@@ -40,23 +40,31 @@ static void xt_rateest_hash_insert(struc
hlist_add_head(>list, _hash[h]);
 }
 
-struct xt_rateest *xt_rateest_lookup(const char *name)
+static struct xt_rateest *__xt_rateest_lookup(const char *name)
 {
struct xt_rateest *est;
unsigned int h;
 
h = xt_rateest_hash(name);
-   mutex_lock(_rateest_mutex);
hlist_for_each_entry(est, _hash[h], list) {
if (strcmp(est->name, name) == 0) {
est->refcnt++;
-   mutex_unlock(_rateest_mutex);
return est;
}
}
-   mutex_unlock(_rateest_mutex);
+
return NULL;
 }
+
+struct xt_rateest *xt_rateest_lookup(const char *name)
+{
+   struct xt_rateest *est;
+
+   mutex_lock(_rateest_mutex);
+   est = __xt_rateest_lookup(name);
+   mutex_unlock(_rateest_mutex);
+   return est;
+}
 EXPORT_SYMBOL_GPL(xt_rateest_lookup);
 
 void xt_rateest_put(struct xt_rateest *est)
@@ -104,8 +112,10 @@ static int xt_rateest_tg_checkentry(cons
rnd_inited = true;
}
 
-   est = xt_rateest_lookup(info->name);
+   mutex_lock(_rateest_mutex);
+   est = __xt_rateest_lookup(info->name);
if (est) {
+   mutex_unlock(_rateest_mutex);
/*
 * If estimator parameters are specified, they must match the
 * existing estimator.
@@ -143,11 +153,13 @@ static int xt_rateest_tg_checkentry(cons
 
info->est = est;
xt_rateest_hash_insert(est);
+   mutex_unlock(_rateest_mutex);
return 0;
 
 err2:
kfree(est);
 err1:
+   mutex_unlock(_rateest_mutex);
return ret;
 }