[RFC][PATCH v2 3/5] clone: Disallown CLONE_THREAD with a shared sighand_struct
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From: Eric W. Biederman <hidden>
Date: 2017-04-02 22:58:21
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lkml
Subsystem:
exec & binfmt api, elf, memory management - core, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2017-04-05 · Re: [RFC][PATCH v2 3/5] clone: Disallown CLONE_THREAD with a shared sighand_struct · Oleg Nesterov <oleg@redhat.com>
- 2017-04-05 · Re: [RFC][PATCH v2 3/5] clone: Disallown CLONE_THREAD with a shared sighand_struct · Eric W. Biederman <hidden>
Old threading libraries used CLONE_SIGHAND without clone thread. Modern threadding libraries always use CLONE_SIGHAND | CLONE_THREAD. Therefore let's simplify our lives and stop supporting a case no one cares about. Signed-off-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> --- kernel/fork.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/fork.c b/kernel/fork.c
index fe6f1bf32bb9..0632ac1180be 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -1515,6 +1515,13 @@ static __latent_entropy struct task_struct *copy_process( if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) return ERR_PTR(-EINVAL); + /* Disallow CLONE_THREAD with a shared SIGHAND structure. No + * one cares and supporting it leads to unnecessarily complex + * code. + */ + if ((clone_flags & CLONE_THREAD) && (atomic_read(¤t->sighand->count) > 1)) + return ERR_PTR(-EINVAL); + /* * Shared signal handlers imply shared VM. By way of the above, * thread groups also imply shared VM. Blocking this case allows
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2.10.1