From 3997c01d260ed00d712b051fdab022a08719441e Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 11:15:06 +0200 Subject: [PATCH] ceph: convert ceph_mds_session.s_ref 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: Ilya Dryomov --- fs/ceph/mds_client.c | 18 +++++++++--------- fs/ceph/mds_client.h | 5 +++-- 2 files changed, 12 insertions(+), 11 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index c681762d76e6..074490542b4c 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -378,9 +378,9 @@ const char *ceph_session_state_name(int s) static struct ceph_mds_session *get_session(struct ceph_mds_session *s) { - if (atomic_inc_not_zero(&s->s_ref)) { + if (refcount_inc_not_zero(&s->s_ref)) { dout("mdsc get_session %p %d -> %d\n", s, - atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref)); + refcount_read(&s->s_ref)-1, refcount_read(&s->s_ref)); return s; } else { dout("mdsc get_session %p 0 -- FAIL", s); @@ -391,8 +391,8 @@ static struct ceph_mds_session *get_session(struct ceph_mds_session *s) void ceph_put_mds_session(struct ceph_mds_session *s) { dout("mdsc put_session %p %d -> %d\n", s, - atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1); - if (atomic_dec_and_test(&s->s_ref)) { + refcount_read(&s->s_ref), refcount_read(&s->s_ref)-1); + if (refcount_dec_and_test(&s->s_ref)) { if (s->s_auth.authorizer) ceph_auth_destroy_authorizer(s->s_auth.authorizer); kfree(s); @@ -411,7 +411,7 @@ struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc, return NULL; session = mdsc->sessions[mds]; dout("lookup_mds_session %p %d\n", session, - atomic_read(&session->s_ref)); + refcount_read(&session->s_ref)); get_session(session); return session; } @@ -466,7 +466,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc, INIT_LIST_HEAD(&s->s_caps); s->s_nr_caps = 0; s->s_trim_caps = 0; - atomic_set(&s->s_ref, 1); + refcount_set(&s->s_ref, 1); INIT_LIST_HEAD(&s->s_waiting); INIT_LIST_HEAD(&s->s_unsafe); s->s_num_cap_releases = 0; @@ -494,7 +494,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc, } mdsc->sessions[mds] = s; atomic_inc(&mdsc->num_sessions); - atomic_inc(&s->s_ref); /* one ref to sessions[], one to caller */ + refcount_inc(&s->s_ref); /* one ref to sessions[], one to caller */ ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds, ceph_mdsmap_get_addr(mdsc->mdsmap, mds)); @@ -3881,7 +3881,7 @@ static struct ceph_connection *con_get(struct ceph_connection *con) struct ceph_mds_session *s = con->private; if (get_session(s)) { - dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref)); + dout("mdsc con_get %p ok (%d)\n", s, refcount_read(&s->s_ref)); return con; } dout("mdsc con_get %p FAIL\n", s); @@ -3892,7 +3892,7 @@ static void con_put(struct ceph_connection *con) { struct ceph_mds_session *s = con->private; - dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref) - 1); + dout("mdsc con_put %p (%d)\n", s, refcount_read(&s->s_ref) - 1); ceph_put_mds_session(s); } diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h index ac0475a2daa7..bbebcd55d79e 100644 --- a/fs/ceph/mds_client.h +++ b/fs/ceph/mds_client.h @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -156,7 +157,7 @@ struct ceph_mds_session { unsigned long s_renew_requested; /* last time we sent a renew req */ u64 s_renew_seq; - atomic_t s_ref; + refcount_t s_ref; struct list_head s_waiting; /* waiting requests */ struct list_head s_unsafe; /* unsafe requests */ }; @@ -373,7 +374,7 @@ __ceph_lookup_mds_session(struct ceph_mds_client *, int mds); static inline struct ceph_mds_session * ceph_get_mds_session(struct ceph_mds_session *s) { - atomic_inc(&s->s_ref); + refcount_inc(&s->s_ref); return s; } -- 2.20.1