From: Reshetova, Elena Date: Tue, 4 Jul 2017 12:52:58 +0000 (+0300) Subject: net, l2tp: convert l2tp_session.ref_count from atomic_t to refcount_t X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~7517^2~7^2~33 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=f00c854c965fd7197c9ac0f59d823ca0a909e33b;p=mirror_ubuntu-focal-kernel.git net, l2tp: convert l2tp_session.ref_count 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 --- diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 203c4aa3e916..b0c2d4ae781d 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1854,7 +1854,7 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn /* Bump the reference count. The session context is deleted * only when this drops to zero. */ - l2tp_session_inc_refcount(session); + refcount_set(&session->ref_count, 1); l2tp_tunnel_inc_refcount(tunnel); /* Ensure tunnel socket isn't deleted */ diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index da58fad2451b..cdb6e3327f74 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -99,7 +99,7 @@ struct l2tp_session { int nr_oos_count; /* For OOS recovery */ int nr_oos_count_max; struct hlist_node hlist; /* Hash list node */ - atomic_t ref_count; + refcount_t ref_count; char name[32]; /* for logging */ char ifname[IFNAMSIZ]; @@ -274,12 +274,12 @@ int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg); */ static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session) { - atomic_inc(&session->ref_count); + refcount_inc(&session->ref_count); } static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) { - if (atomic_dec_and_test(&session->ref_count)) + if (refcount_dec_and_test(&session->ref_count)) l2tp_session_free(session); } @@ -288,14 +288,14 @@ static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session) do { \ pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n", \ __func__, __LINE__, (_s)->name, \ - atomic_read(&_s->ref_count)); \ + refcount_read(&_s->ref_count)); \ l2tp_session_inc_refcount_1(_s); \ } while (0) #define l2tp_session_dec_refcount(_s) \ do { \ pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n", \ __func__, __LINE__, (_s)->name, \ - atomic_read(&_s->ref_count)); \ + refcount_read(&_s->ref_count)); \ l2tp_session_dec_refcount_1(_s); \ } while (0) #else