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b=jbfKXfK0mE9O3f5dMY3E4dVKm5jEKviPm3oJiS/gqHdTHREyIh+YUPuPXL72lLNqS qv6lR4nMb2tNem1jeiCHP60PTjurfc4Kkb4ybGEFDOcJybT0jNRotx+KtIURUK7hMx e8pKFsN3Ml2gc0P8UrrNG/Ff3N4kmnDWrqXWZirAEUeRCLoXqB2nE6nz/flhtm5ytw +kABmsUcQJNp+z7TePeUJI3hEVstmyGsVafoOoKy0j/uN2KcxJZRwvdtpIor09m53o dC1ddPZ03jJ7lhKjadb0ByajF8+STLOQc6rac31L3IPJyObUjVTVYsvpwaji5ZuV0n hbPucduHDXx9w== From: Jonathan Corbet To: =?utf-8?B?TWljaGHFgiBDxYJhcGnFhHNraQ==?= Cc: Mike Kravetz , Muchun Song , Andrew Morton , Hugh Dickins , Shuah Khan , Greg Kroah-Hartman , Arnd Bergmann , Yi Liu , Dominik Brodowski , Hans Verkuil , Steve French , Simon Ser , Jason Gunthorpe , Marc Dionne , Jiri Slaby , David Howells , Luca Vizzarro , Jeff Xu , Aleksa Sarai , Kees Cook , Daniel Verkamp , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v2 0/2] mm/memfd: add ioctl(MEMFD_CHECK_IF_ORIGINAL) In-Reply-To: References: <20230908175738.41895-1-mclapinski@google.com> <87tts4z9nu.fsf@meer.lwn.net> Date: Fri, 08 Sep 2023 16:07:00 -0600 Message-ID: <87h6o4z5dn.fsf@meer.lwn.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 086D5140003 X-Rspam-User: X-Stat-Signature: cyh65zoe4jucrgd91a1ykijewx3znyi1 X-Rspamd-Server: rspam03 X-HE-Tag: 1694210822-436414 X-HE-Meta: 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 rZMZypK5 lMcKxUaCnO6UZDrgSY3zal5ODDao03pMKzfTrzSCW7PfRxS0y95rn6rxApdEs2jbod+1xULHonE2J8tSxMQLCl1jy8YVtn52wHd/6Moe5aHd06yqCFDbj7VOzUD+5DB7l6n64LUcaYGSLRBEyfs2Re53VZhzV1/NfVXqkPP90lVtA4X8Z3ghJVR3s2bF8K0v0nv9EfKhXVKfYvEKgfTYeq0DMr4kF84zBw4rGKJq/2Se98EnQZC14h8YAsXwZQns6UHlyf4iWEh0G3IL0yjmXMT8zTxlY2amCbOY2agXf7qK8NBaKYROmrwGm8w== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Micha=C5=82 C=C5=82api=C5=84ski writes: > On Fri, Sep 8, 2023 at 10:34=E2=80=AFPM Jonathan Corbet = wrote: >> Given that the two file descriptors are otherwise indistinguishable, >> might a better fix be to make them indistinguishable in this regard as >> well? Is there a good reason why the second fd doesn't become >> exec()able in this scenario and, if not, perhaps that behavior could be >> changed instead? > > It probably could be changed, yes. But I'm worried that would be > broadening the bug that is the exec()ability of memfds. AFAIK no other > fd that is opened as writable can be exec()ed. If maintainers would > prefer this, I could do this. I'm not convinced that perpetuating the behavior and adding an ioctl() workaround would be better than that; it seems to me that consistency would be better. But I don't have any real say in that matter, of course; I'm curious what others think. Thanks, jon