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Date:   Mon, 10 May 2021 21:02:21 +0300
From:   Mike Rapoport <rppt@kernel.org>
To:     James Bottomley <jejb@linux.ibm.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christopher Lameter <cl@linux.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        David Hildenbrand <david@redhat.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Matthew Garrett <mjg59@srcf.ucam.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Michal Hocko <mhocko@suse.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Peter Zijlstra <peterz@infradead.org>,
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Subject: Re: [PATCH v18 0/9] mm: introduce memfd_secret system call to create
 "secret" memory areas
Message-ID: <YJl1LQvQuxxfGRnJ@kernel.org>
References: <20210303162209.8609-1-rppt@kernel.org>
 <20210505120806.abfd4ee657ccabf2f221a0eb@linux-foundation.org>
 <de27bfae0f4fdcbb0bb4ad17ec5aeffcd774c44b.camel@linux.ibm.com>
 <202105060916.ECDEC21@keescook>
 <9e1953a1412fad06a9f7988a280d2d9a74ab0464.camel@linux.ibm.com>
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On Thu, May 06, 2021 at 11:47:47AM -0700, James Bottomley wrote:
> On Thu, 2021-05-06 at 10:33 -0700, Kees Cook wrote:
> > On Thu, May 06, 2021 at 08:26:41AM -0700, James Bottomley wrote:
> 
> > What's happening with O_CLOEXEC in this code? I don't see that
> > mentioned in the cover letter either. Why is it disallowed? That
> > seems a strange limitation for something trying to avoid leaking
> > secrets into other processes.
> 
> I actually thought we forced it, so I'll let Mike address this.  I
> think allowing it is great, so the secret memory isn't inherited by
> children, but I can see use cases where a process would want its child
> to inherit the secrets.

We do not enforce O_CLOEXEC, but if the user explicitly requested O_CLOEXEC
it would be passed to get_unused_fd_flags().

-- 
Sincerely yours,
Mike.