From 7ff139696d74d0d4917bd259347d00e3a4fcc410 Mon Sep 17 00:00:00 2001 From: "Reshetova, Elena" Date: Tue, 4 Jul 2017 15:53:14 +0300 Subject: [PATCH] net, sunrpc: convert gss_upcall_msg.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 --- net/sunrpc/auth_gss/auth_gss.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index 72f129c74acd..9463af4b32e8 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -287,7 +287,7 @@ err: #define UPCALL_BUF_LEN 128 struct gss_upcall_msg { - atomic_t count; + refcount_t count; kuid_t uid; struct rpc_pipe_msg msg; struct list_head list; @@ -328,7 +328,7 @@ static void gss_release_msg(struct gss_upcall_msg *gss_msg) { struct net *net = gss_msg->auth->net; - if (!atomic_dec_and_test(&gss_msg->count)) + if (!refcount_dec_and_test(&gss_msg->count)) return; put_pipe_version(net); BUG_ON(!list_empty(&gss_msg->list)); @@ -348,7 +348,7 @@ __gss_find_upcall(struct rpc_pipe *pipe, kuid_t uid, const struct gss_auth *auth continue; if (auth && pos->auth->service != auth->service) continue; - atomic_inc(&pos->count); + refcount_inc(&pos->count); dprintk("RPC: %s found msg %p\n", __func__, pos); return pos; } @@ -369,7 +369,7 @@ gss_add_msg(struct gss_upcall_msg *gss_msg) spin_lock(&pipe->lock); old = __gss_find_upcall(pipe, gss_msg->uid, gss_msg->auth); if (old == NULL) { - atomic_inc(&gss_msg->count); + refcount_inc(&gss_msg->count); list_add(&gss_msg->list, &pipe->in_downcall); } else gss_msg = old; @@ -383,7 +383,7 @@ __gss_unhash_msg(struct gss_upcall_msg *gss_msg) list_del_init(&gss_msg->list); rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno); wake_up_all(&gss_msg->waitqueue); - atomic_dec(&gss_msg->count); + refcount_dec(&gss_msg->count); } static void @@ -506,7 +506,7 @@ gss_alloc_msg(struct gss_auth *gss_auth, INIT_LIST_HEAD(&gss_msg->list); rpc_init_wait_queue(&gss_msg->rpc_waitqueue, "RPCSEC_GSS upcall waitq"); init_waitqueue_head(&gss_msg->waitqueue); - atomic_set(&gss_msg->count, 1); + refcount_set(&gss_msg->count, 1); gss_msg->uid = uid; gss_msg->auth = gss_auth; switch (vers) { @@ -542,11 +542,11 @@ gss_setup_upcall(struct gss_auth *gss_auth, struct rpc_cred *cred) gss_msg = gss_add_msg(gss_new); if (gss_msg == gss_new) { int res; - atomic_inc(&gss_msg->count); + refcount_inc(&gss_msg->count); res = rpc_queue_upcall(gss_new->pipe, &gss_new->msg); if (res) { gss_unhash_msg(gss_new); - atomic_dec(&gss_msg->count); + refcount_dec(&gss_msg->count); gss_release_msg(gss_new); gss_msg = ERR_PTR(res); } @@ -595,7 +595,7 @@ gss_refresh_upcall(struct rpc_task *task) task->tk_timeout = 0; gss_cred->gc_upcall = gss_msg; /* gss_upcall_callback will release the reference to gss_upcall_msg */ - atomic_inc(&gss_msg->count); + refcount_inc(&gss_msg->count); rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback); } else { gss_handle_downcall_result(gss_cred, gss_msg); @@ -815,7 +815,7 @@ restart: if (!list_empty(&gss_msg->msg.list)) continue; gss_msg->msg.errno = -EPIPE; - atomic_inc(&gss_msg->count); + refcount_inc(&gss_msg->count); __gss_unhash_msg(gss_msg); spin_unlock(&pipe->lock); gss_release_msg(gss_msg); @@ -834,7 +834,7 @@ gss_pipe_destroy_msg(struct rpc_pipe_msg *msg) if (msg->errno < 0) { dprintk("RPC: %s releasing msg %p\n", __func__, gss_msg); - atomic_inc(&gss_msg->count); + refcount_inc(&gss_msg->count); gss_unhash_msg(gss_msg); if (msg->errno == -ETIMEDOUT) warn_gssd(); -- 2.20.1