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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2018-08-21 21:55:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-08-22 10:52:46 -0700 |
| commit | fc37191272a972d449bab3d8247cf52cadf5d4e6 (patch) | |
| tree | 17510f69e906aacff6c2a5c89f72ac4f17fb40f4 /include | |
| parent | 060288a7320b2837a8ff2af1b3643bdbd5e568f6 (diff) | |
| download | lwn-fc37191272a972d449bab3d8247cf52cadf5d4e6.tar.gz lwn-fc37191272a972d449bab3d8247cf52cadf5d4e6.zip | |
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')
| -rw-r--r-- | include/linux/sched/user.h | 5 |
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 *); |