From: Elena Reshetova <elena.reshetova@xxxxxxxxx> 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@xxxxxxxxx Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx> Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: David Windsor <dwindsor@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Serge Hallyn <serge@xxxxxxxxxx> Cc: <arozansk@xxxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/ipc_namespace.h | 5 +++-- ipc/msgutil.c | 2 +- ipc/namespace.c | 4 ++-- 3 files changed, 6 insertions(+), 5 deletions(-) diff -puN include/linux/ipc_namespace.h~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t include/linux/ipc_namespace.h --- a/include/linux/ipc_namespace.h~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t +++ a/include/linux/ipc_namespace.h @@ -7,6 +7,7 @@ #include <linux/notifier.h> #include <linux/nsproxy.h> #include <linux/ns_common.h> +#include <linux/refcount.h> struct user_namespace; @@ -19,7 +20,7 @@ struct ipc_ids { }; struct ipc_namespace { - atomic_t count; + refcount_t count; struct ipc_ids ids[3]; int sem_ctls[4]; @@ -118,7 +119,7 @@ extern struct ipc_namespace *copy_ipcs(u static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns) { if (ns) - atomic_inc(&ns->count); + refcount_inc(&ns->count); return ns; } diff -puN ipc/msgutil.c~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t ipc/msgutil.c --- a/ipc/msgutil.c~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t +++ a/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 -puN ipc/namespace.c~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t ipc/namespace.c --- a/ipc/namespace.c~ipc-convert-ipc_namespacecount-from-atomic_t-to-refcount_t +++ a/ipc/namespace.c @@ -50,7 +50,7 @@ static struct ipc_namespace *create_ipc_ 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_names */ 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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
