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Biederman" To: Pedro Falcato Cc: Kees Cook , Alexander Viro , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Sebastian Ott , Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , Andrew Morton , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20230929031716.it.155-kees@kernel.org> <20230929032435.2391507-4-keescook@chromium.org> Date: Fri, 29 Sep 2023 10:32:59 -0500 In-Reply-To: (Pedro Falcato's message of "Fri, 29 Sep 2023 13:12:13 +0100") Message-ID: <87y1gp6llg.fsf@email.froward.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-XM-SPF: eid=1qmFUI-009b5s-TR;;;mid=<87y1gp6llg.fsf@email.froward.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.168.167;;;frm=ebiederm@xmission.com;;;spf=pass X-XM-AID: U2FsdGVkX18dXVfN1YAEePbYpFJoWWbpYNcqcNqjTNI= X-SA-Exim-Connect-IP: 68.227.168.167 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH v4 4/6] binfmt_elf: Use elf_load() for library X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) X-Rspamd-Queue-Id: 26F81C0015 X-Rspam-User: X-Stat-Signature: mia11isqmdhxs761ykamr7hc3pxmis7t X-Rspamd-Server: rspam01 X-HE-Tag: 1696001589-364697 X-HE-Meta: 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 Ign0Aels K21nnTKv0+MFA/GVKM41vS5p5hfLmeWcGmcU9TAWd8v/eKWNJ+tms03n8lNHGuuKPjJg/FTI/qVyX7RrEHHxnidfN8fDXzFPVcqTfnUF7M7i5zA/mF19QXhkUDwDy+iPmc2/dtCW1ZrMn0Gl23wMnC3yjSPqqutwelZJvas0LBpV44ePk3vYnd7XQRdvw8on/W6ih5bT5aYHQlK7Jlq9LtP6SyB9DS+JU3Qo+r4+SLVWj/CRbdVTOcagkXaNoKmicf0zrlcA4BiLqcvH3GbYcdVpgSJ/4rJGmPItx8OnKeZAHz7s= 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: Pedro Falcato writes: > On Fri, Sep 29, 2023 at 4:24=E2=80=AFAM Kees Cook = wrote: >> >> While load_elf_library() is a libc5-ism, we can still replace most of >> its contents with elf_load() as well, further simplifying the code. > > While I understand you want to break as little as possible (as the ELF > loader maintainer), I'm wondering if we could axe CONFIG_USELIB > altogether? Since CONFIG_BINFMT_AOUT also got axed. Does this have > users anywhere? As I recall: - libc4 was a.out and used uselib. - libc5 was elf and used uselib. - libc6 is elf and has never used uselib. Anything using libc5 is extremely rare. It is an entire big process to see if there are any users in existence. In the meantime changing load_elf_library to use elf_load removes any maintenance burden. Eric