From 8851ab526791530d00bbbd0952512d68684a44b8 Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Fri, 30 Jun 2017 13:08:02 +0300 Subject: [PATCH] net: convert ip_mc_list.refcnt from atomic_t to refcount_t 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 Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller --- include/linux/igmp.h | 3 ++- net/ipv4/igmp.c | 10 +++++----- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/igmp.h b/include/linux/igmp.h index 12f6fba6d21a..97caf1821de8 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -18,6 +18,7 @@ #include #include #include +#include #include static inline struct igmphdr *igmp_hdr(const struct sk_buff *skb) @@ -84,7 +85,7 @@ struct ip_mc_list { struct ip_mc_list __rcu *next_hash; struct timer_list timer; int users; - atomic_t refcnt; + refcount_t refcnt; spinlock_t lock; char tm_running; char reporter; diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index c4032302d7cd..28f14afd0dd3 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -173,7 +173,7 @@ static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode, static void ip_ma_put(struct ip_mc_list *im) { - if (atomic_dec_and_test(&im->refcnt)) { + if (refcount_dec_and_test(&im->refcnt)) { in_dev_put(im->interface); kfree_rcu(im, rcu); } @@ -199,7 +199,7 @@ static void igmp_stop_timer(struct ip_mc_list *im) { spin_lock_bh(&im->lock); if (del_timer(&im->timer)) - atomic_dec(&im->refcnt); + refcount_dec(&im->refcnt); im->tm_running = 0; im->reporter = 0; im->unsolicit_count = 0; @@ -213,7 +213,7 @@ static void igmp_start_timer(struct ip_mc_list *im, int max_delay) im->tm_running = 1; if (!mod_timer(&im->timer, jiffies+tv+2)) - atomic_inc(&im->refcnt); + refcount_inc(&im->refcnt); } static void igmp_gq_start_timer(struct in_device *in_dev) @@ -249,7 +249,7 @@ static void igmp_mod_timer(struct ip_mc_list *im, int max_delay) spin_unlock_bh(&im->lock); return; } - atomic_dec(&im->refcnt); + refcount_dec(&im->refcnt); } igmp_start_timer(im, max_delay); spin_unlock_bh(&im->lock); @@ -1374,7 +1374,7 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr) /* initial mode is (EX, empty) */ im->sfmode = MCAST_EXCLUDE; im->sfcount[MCAST_EXCLUDE] = 1; - atomic_set(&im->refcnt, 1); + refcount_set(&im->refcnt, 1); spin_lock_init(&im->lock); #ifdef CONFIG_IP_MULTICAST setup_timer(&im->timer, igmp_timer_expire, (unsigned long)im);