diff options
| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-02-20 12:19:00 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-03-06 14:55:22 -0500 |
| commit | 387ad9674b0013c8756ad20d854ff005b0c313ad (patch) | |
| tree | 4e019a943d277232afdd5421276cc48829008214 | |
| parent | c1ae3cfa0e89fa1a7ecc4c99031f5e9ae99d9201 (diff) | |
kernel: convert cgroup_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.
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>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | include/linux/cgroup.h | 7 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 2 | ||||
| -rw-r--r-- | kernel/cgroup/namespace.c | 2 |
3 files changed, 6 insertions, 5 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index f6b43fbb141c..44129793c7b8 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -22,6 +22,7 @@ #include <linux/ns_common.h> #include <linux/nsproxy.h> #include <linux/user_namespace.h> +#include <linux/refcount.h> #include <linux/cgroup-defs.h> @@ -640,7 +641,7 @@ static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} #endif /* CONFIG_CGROUP_DATA */ struct cgroup_namespace { - atomic_t count; + refcount_t count; struct ns_common ns; struct user_namespace *user_ns; struct ucounts *ucounts; @@ -675,12 +676,12 @@ copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, static inline void get_cgroup_ns(struct cgroup_namespace *ns) { if (ns) - atomic_inc(&ns->count); + refcount_inc(&ns->count); } static inline void put_cgroup_ns(struct cgroup_namespace *ns) { - if (ns && atomic_dec_and_test(&ns->count)) + if (ns && refcount_dec_and_test(&ns->count)) free_cgroup_ns(ns); } diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 0125589c7428..8ee78688e36d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -189,7 +189,7 @@ static u16 have_canfork_callback __read_mostly; /* cgroup namespace for init task */ struct cgroup_namespace init_cgroup_ns = { - .count = { .counter = 2, }, + .count = REFCOUNT_INIT(2), .user_ns = &init_user_ns, .ns.ops = &cgroupns_operations, .ns.inum = PROC_CGROUP_INIT_INO, diff --git a/kernel/cgroup/namespace.c b/kernel/cgroup/namespace.c index 96d38dab6fb2..66129eb4371d 100644 --- a/kernel/cgroup/namespace.c +++ b/kernel/cgroup/namespace.c @@ -31,7 +31,7 @@ static struct cgroup_namespace *alloc_cgroup_ns(void) kfree(new_ns); return ERR_PTR(ret); } - atomic_set(&new_ns->count, 1); + refcount_set(&new_ns->count, 1); new_ns->ns.ops = &cgroupns_operations; return new_ns; } |