[PATCH 1/7] net, netfilter: convert ip_vs_conn.refcnt from atomic_t to refcount_t

From: Elena Reshetova
Date: Wed Mar 15 2017 - 07:13:26 EST

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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
include/net/ip_vs.h | 8 +++++---
net/netfilter/ipvs/ip_vs_conn.c | 24 ++++++++++++------------
net/netfilter/ipvs/ip_vs_core.c | 4 ++--
net/netfilter/ipvs/ip_vs_proto_sctp.c | 2 +-
net/netfilter/ipvs/ip_vs_proto_tcp.c | 2 +-
5 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 7bdfa7d..f1429c3 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -12,6 +12,8 @@
#include <linux/list.h> /* for struct list_head */
#include <linux/spinlock.h> /* for struct rwlock_t */
#include <linux/atomic.h> /* for struct atomic_t */
+#include <linux/refcount.h> /* for struct refcount_t */
+
#include <linux/compiler.h>
#include <linux/timer.h>
#include <linux/bug.h>
@@ -525,7 +527,7 @@ struct ip_vs_conn {
struct netns_ipvs *ipvs;

/* counter and timer */
- atomic_t refcnt; /* reference count */
+ refcount_t refcnt; /* reference count */
struct timer_list timer; /* Expiration timer */
volatile unsigned long timeout; /* timeout */

@@ -1211,14 +1213,14 @@ struct ip_vs_conn * ip_vs_conn_out_get_proto(struct netns_ipvs *ipvs, int af,
*/
static inline bool __ip_vs_conn_get(struct ip_vs_conn *cp)
{
- return atomic_inc_not_zero(&cp->refcnt);
+ return refcount_inc_not_zero(&cp->refcnt);
}

/* put back the conn without restarting its timer */
static inline void __ip_vs_conn_put(struct ip_vs_conn *cp)
{
smp_mb__before_atomic();
- atomic_dec(&cp->refcnt);
+ refcount_dec(&cp->refcnt);
}
void ip_vs_conn_put(struct ip_vs_conn *cp);
void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport);
diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index e6a2753..3d2ac71a 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -181,7 +181,7 @@ static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)

if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
cp->flags |= IP_VS_CONN_F_HASHED;
- atomic_inc(&cp->refcnt);
+ refcount_inc(&cp->refcnt);
hlist_add_head_rcu(&cp->c_list, &ip_vs_conn_tab[hash]);
ret = 1;
} else {
@@ -215,7 +215,7 @@ static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
if (cp->flags & IP_VS_CONN_F_HASHED) {
hlist_del_rcu(&cp->c_list);
cp->flags &= ~IP_VS_CONN_F_HASHED;
- atomic_dec(&cp->refcnt);
+ refcount_dec(&cp->refcnt);
ret = 1;
} else
ret = 0;
@@ -242,13 +242,13 @@ static inline bool ip_vs_conn_unlink(struct ip_vs_conn *cp)
if (cp->flags & IP_VS_CONN_F_HASHED) {
ret = false;
/* Decrease refcnt and unlink conn only if we are last user */
- if (atomic_cmpxchg(&cp->refcnt, 1, 0) == 1) {
+ if (refcount_dec_if_one(&cp->refcnt)) {
hlist_del_rcu(&cp->c_list);
cp->flags &= ~IP_VS_CONN_F_HASHED;
ret = true;
}
} else
- ret = atomic_read(&cp->refcnt) ? false : true;
+ ret = refcount_read(&cp->refcnt) ? false : true;

spin_unlock(&cp->lock);
ct_write_unlock_bh(hash);
@@ -475,7 +475,7 @@ static void __ip_vs_conn_put_timer(struct ip_vs_conn *cp)
void ip_vs_conn_put(struct ip_vs_conn *cp)
{
if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) &&
- (atomic_read(&cp->refcnt) == 1) &&
+ (refcount_read(&cp->refcnt) == 1) &&
!timer_pending(&cp->timer))
/* expire connection immediately */
__ip_vs_conn_put_notimer(cp);
@@ -617,8 +617,8 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
ip_vs_fwd_tag(cp), cp->state,
- cp->flags, atomic_read(&cp->refcnt),
- atomic_read(&dest->refcnt));
+ cp->flags, refcount_read(&cp->refcnt),
+ refcount_read(&dest->refcnt));

/* Update the connection counters */
if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
@@ -714,8 +714,8 @@ static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
ip_vs_fwd_tag(cp), cp->state,
- cp->flags, atomic_read(&cp->refcnt),
- atomic_read(&dest->refcnt));
+ cp->flags, refcount_read(&cp->refcnt),
+ refcount_read(&dest->refcnt));

/* Update the connection counters */
if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
@@ -863,10 +863,10 @@ static void ip_vs_conn_expire(unsigned long data)

expire_later:
IP_VS_DBG(7, "delayed: conn->refcnt=%d conn->n_control=%d\n",
- atomic_read(&cp->refcnt),
+ refcount_read(&cp->refcnt),
atomic_read(&cp->n_control));

- atomic_inc(&cp->refcnt);
+ refcount_inc(&cp->refcnt);
cp->timeout = 60*HZ;

if (ipvs->sync_state & IP_VS_STATE_MASTER)
@@ -941,7 +941,7 @@ ip_vs_conn_new(const struct ip_vs_conn_param *p, int dest_af,
* it in the table, so that other thread run ip_vs_random_dropentry
* but cannot drop this entry.
*/
- atomic_set(&cp->refcnt, 1);
+ refcount_set(&cp->refcnt, 1);

cp->control = NULL;
atomic_set(&cp->n_control, 0);
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index db40050..a3e1b9c 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -542,7 +542,7 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
- cp->flags, atomic_read(&cp->refcnt));
+ cp->flags, refcount_read(&cp->refcnt));

ip_vs_conn_stats(cp, svc);
return cp;
@@ -1193,7 +1193,7 @@ struct ip_vs_conn *ip_vs_new_conn_out(struct ip_vs_service *svc,
IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
- cp->flags, atomic_read(&cp->refcnt));
+ cp->flags, refcount_read(&cp->refcnt));
LeaveFunction(12);
return cp;
}
diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c
index d952d67..56f8e4b 100644
--- a/net/netfilter/ipvs/ip_vs_proto_sctp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c
@@ -447,7 +447,7 @@ set_sctp_state(struct ip_vs_proto_data *pd, struct ip_vs_conn *cp,
ntohs(cp->cport),
sctp_state_name(cp->state),
sctp_state_name(next_state),
- atomic_read(&cp->refcnt));
+ refcount_read(&cp->refcnt));
if (dest) {
if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
(next_state != IP_VS_SCTP_S_ESTABLISHED)) {
diff --git a/net/netfilter/ipvs/ip_vs_proto_tcp.c b/net/netfilter/ipvs/ip_vs_proto_tcp.c
index 5117bcb..12dc8d5 100644
--- a/net/netfilter/ipvs/ip_vs_proto_tcp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_tcp.c
@@ -557,7 +557,7 @@ set_tcp_state(struct ip_vs_proto_data *pd, struct ip_vs_conn *cp,
ntohs(cp->cport),
tcp_state_name(cp->state),
tcp_state_name(new_state),
- atomic_read(&cp->refcnt));
+ refcount_read(&cp->refcnt));

if (dest) {
if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
--
2.7.4

Next message: Lee Jones: "Re: [PATCH v3 5/5] phy: exynos: Use one define for enable bit"
Previous message: Heiko Stübner: "Re: [PATCH v1 0/7] initialize dtsi file and dts file for RK3328 SoCs"
In reply to: Elena Reshetova: "[PATCH 6/7] net, netfilter: convert nfulnl_instance.use from atomic_t to refcount_t"
Next in thread: Pablo Neira Ayuso: "Re: [PATCH 0/7] net, netfilter refcounter conversions"
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