ipc: convert ipc_namespace.count from atomic_t to refcount_t (a2e0602c) · Commits · 戴 / test

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 <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> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: <arozansk@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/ipc_namespace.h

+3 −2

Original line number	Diff line number	Diff line
		@@ -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(unsigned long flags,
		static inline struct ipc_namespace get_ipc_ns(struct ipc_namespace ns)
		{
		if (ns)
		atomic_inc(&ns->count);
		refcount_inc(&ns->count);
		return ns;
		}

ipc/msgutil.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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

ipc/namespace.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);

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