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Subject[PATCH 01/18] net, llc: convert llc_sap.refcnt from atomic_t to refcount_t
Date
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@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
include/net/llc.h | 6 +++---
net/llc/llc_core.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/net/llc.h b/include/net/llc.h
index e8e61d4..dc35f25 100644
--- a/include/net/llc.h
+++ b/include/net/llc.h
@@ -55,7 +55,7 @@ struct llc_sap {
unsigned char state;
unsigned char p_bit;
unsigned char f_bit;
- atomic_t refcnt;
+ refcount_t refcnt;
int (*rcv_func)(struct sk_buff *skb,
struct net_device *dev,
struct packet_type *pt,
@@ -113,14 +113,14 @@ struct llc_sap *llc_sap_open(unsigned char lsap,
struct net_device *orig_dev));
static inline void llc_sap_hold(struct llc_sap *sap)
{
- atomic_inc(&sap->refcnt);
+ refcount_inc(&sap->refcnt);
}

void llc_sap_close(struct llc_sap *sap);

static inline void llc_sap_put(struct llc_sap *sap)
{
- if (atomic_dec_and_test(&sap->refcnt))
+ if (refcount_dec_and_test(&sap->refcnt))
llc_sap_close(sap);
}

diff --git a/net/llc/llc_core.c b/net/llc/llc_core.c
index 842851c..8904126 100644
--- a/net/llc/llc_core.c
+++ b/net/llc/llc_core.c
@@ -41,7 +41,7 @@ static struct llc_sap *llc_sap_alloc(void)
spin_lock_init(&sap->sk_lock);
for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++)
INIT_HLIST_NULLS_HEAD(&sap->sk_laddr_hash[i], i);
- atomic_set(&sap->refcnt, 1);
+ refcount_set(&sap->refcnt, 1);
}
return sap;
}
--
2.7.4
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