ipc: convert sem_undo_list.refcnt 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/1499417992-3238-3-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>
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@ -122,7 +122,7 @@ struct sem_undo {
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* that may be shared among all a CLONE_SYSVSEM task group.
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*/
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struct sem_undo_list {
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atomic_t refcnt;
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refcount_t refcnt;
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spinlock_t lock;
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struct list_head list_proc;
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};
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@ -1642,7 +1642,7 @@ static inline int get_undo_list(struct sem_undo_list **undo_listp)
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if (undo_list == NULL)
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return -ENOMEM;
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spin_lock_init(&undo_list->lock);
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atomic_set(&undo_list->refcnt, 1);
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refcount_set(&undo_list->refcnt, 1);
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INIT_LIST_HEAD(&undo_list->list_proc);
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current->sysvsem.undo_list = undo_list;
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@ -2041,7 +2041,7 @@ int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
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error = get_undo_list(&undo_list);
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if (error)
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return error;
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atomic_inc(&undo_list->refcnt);
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refcount_inc(&undo_list->refcnt);
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tsk->sysvsem.undo_list = undo_list;
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} else
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tsk->sysvsem.undo_list = NULL;
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@ -2070,7 +2070,7 @@ void exit_sem(struct task_struct *tsk)
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return;
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tsk->sysvsem.undo_list = NULL;
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if (!atomic_dec_and_test(&ulp->refcnt))
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if (!refcount_dec_and_test(&ulp->refcnt))
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return;
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for (;;) {
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