From a2e0602c36ed9fe042714694dd5a889ecd8cb556 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 8 Sep 2017 16:17:38 -0700 Subject: ipc: convert ipc_namespace.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. Link: http://lkml.kernel.org/r/1499417992-3238-2-git-send-email-elena.reshetova@intel.com Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Cc: Peter Zijlstra Cc: Greg Kroah-Hartman Cc: "Eric W. Biederman" Cc: Ingo Molnar Cc: Alexey Dobriyan Cc: Serge Hallyn Cc: Cc: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/msgutil.c | 2 +- ipc/namespace.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'ipc') diff --git a/ipc/msgutil.c b/ipc/msgutil.c index bf74eaa5c39f..84598025a6ad 100644 --- a/ipc/msgutil.c +++ b/ipc/msgutil.c @@ -29,7 +29,7 @@ DEFINE_SPINLOCK(mq_lock); * and not CONFIG_IPC_NS. */ struct ipc_namespace init_ipc_ns = { - .count = ATOMIC_INIT(1), + .count = REFCOUNT_INIT(1), .user_ns = &init_user_ns, .ns.inum = PROC_IPC_INIT_INO, #ifdef CONFIG_IPC_NS diff --git a/ipc/namespace.c b/ipc/namespace.c index b4d80f9f7246..7af6e6b883b9 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -50,7 +50,7 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, goto fail_free; ns->ns.ops = &ipcns_operations; - atomic_set(&ns->count, 1); + refcount_set(&ns->count, 1); ns->user_ns = get_user_ns(user_ns); ns->ucounts = ucounts; @@ -144,7 +144,7 @@ static void free_ipc_ns(struct ipc_namespace *ns) */ void put_ipc_ns(struct ipc_namespace *ns) { - if (atomic_dec_and_lock(&ns->count, &mq_lock)) { + if (refcount_dec_and_lock(&ns->count, &mq_lock)) { mq_clear_sbinfo(ns); spin_unlock(&mq_lock); mq_put_mnt(ns); -- cgit