summaryrefslogtreecommitdiff
path: root/include/linux
diff options
context:
space:
mode:
authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2018-08-22 07:55:38 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 20:52:46 +0300
commitfc37191272a972d449bab3d8247cf52cadf5d4e6 (patch)
tree17510f69e906aacff6c2a5c89f72ac4f17fb40f4 /include/linux
parent060288a7320b2837a8ff2af1b3643bdbd5e568f6 (diff)
downloadlinux-fc37191272a972d449bab3d8247cf52cadf5d4e6.tar.xz
userns: use refcount_t for reference counting instead atomic_t
refcount_t type and corresponding API should be used instead of atomic_t wh en the variable is used as a reference counter. This avoids accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/20180703200141.28415-6-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/sched/user.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h
index 96fe289c4c6e..39ad98c09c58 100644
--- a/include/linux/sched/user.h
+++ b/include/linux/sched/user.h
@@ -4,6 +4,7 @@
#include <linux/uidgid.h>
#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/ratelimit.h>
struct key;
@@ -12,7 +13,7 @@ struct key;
* Some day this will be a full-fledged user tracking system..
*/
struct user_struct {
- atomic_t __count; /* reference count */
+ refcount_t __count; /* reference count */
atomic_t processes; /* How many processes does this user have? */
atomic_t sigpending; /* How many pending signals does this user have? */
#ifdef CONFIG_FANOTIFY
@@ -59,7 +60,7 @@ extern struct user_struct root_user;
extern struct user_struct * alloc_uid(kuid_t);
static inline struct user_struct *get_uid(struct user_struct *u)
{
- atomic_inc(&u->__count);
+ refcount_inc(&u->__count);
return u;
}
extern void free_uid(struct user_struct *);