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a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1695346152; bh=b9gW9MIcyJlWGdZgvLY+dtieW9BAuI8bt7DipfXBSqI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=u/GhEEGvLTbxweuNixKTTgDjLXMrk3GdhOT2YlQGOuMn0J57nwZW/iUTh5LG1nPGy X41WWqfXv+qtW3gZ0X+1O99Y+P4TQkx32/f5U2rcwzNEj028SHTPgpQZksqwgfY64v 7+fJofXzg151864g5VRBhHehSL1X+l4VvZKPm0bA= Date: Thu, 21 Sep 2023 18:29:10 -0700 From: Andrew Morton To: Florent Revest Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, catalin.marinas@arm.com, anshuman.khandual@arm.com, joey.gouly@arm.com, mhocko@suse.com, keescook@chromium.org, david@redhat.com, peterx@redhat.com, izbyshev@ispras.ru, broonie@kernel.org, szabolcs.nagy@arm.com, kpsingh@kernel.org, gthelen@google.com, toiwoton@gmail.com, ayush.jain3@amd.com, stable@vger.kernel.org Subject: Re: [PATCH v4 4/6] mm: Make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long Message-Id: <20230921182910.2fcce58b27b23f767050033c@linux-foundation.org> In-Reply-To: <20230828150858.393570-5-revest@chromium.org> References: <20230828150858.393570-1-revest@chromium.org> <20230828150858.393570-5-revest@chromium.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 919604000B X-Stat-Signature: cc6soahte1stj5w3g7ahgudouuky3q1p X-HE-Tag: 1695346153-568492 X-HE-Meta: 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 /XoUCYOg 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 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: On Mon, 28 Aug 2023 17:08:56 +0200 Florent Revest wrote: > Defining a prctl flag as an int is a footgun because on a 64 bit machine > and with a variadic implementation of prctl (like in musl and glibc), > when used directly as a prctl argument, it can get casted to long with > garbage upper bits which would result in unexpected behaviors. > > This patch changes the constant to an unsigned long to eliminate that > possibilities. This does not break UAPI. > > Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl") > Cc: stable@vger.kernel.org > Signed-off-by: Florent Revest > Suggested-by: Alexey Izbyshev > Reviewed-by: David Hildenbrand > Reviewed-by: Kees Cook > Acked-by: Catalin Marinas Why is this being offered to -stable? Does it fix any known problem?