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Message-ID: <62d1c43c-18e5-4ddf-ad85-c47e5c58d79a@I-love.SAKURA.ne.jp>
Date: Thu, 25 Jan 2024 23:34:00 +0900
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Subject: Re: [PATCH] exec: Check __FMODE_EXEC instead of in_execve for LSMs
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To: Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Kevin Locke <kevin@kevinlocke.name>,
        John Johansen <john.johansen@canonical.com>,
        Paul Moore
 <paul@paul-moore.com>, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Kentaro Takeda
 <takedakn@nttdata.co.jp>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
        Eric Biederman <ebiederm@xmission.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20240124192228.work.788-kees@kernel.org>
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 <202401241310.0A158998@keescook>
 <CAG48ez1tcxtEwWgxSUqLDcYbrkY=UM3hz22A0BTvTYq4BGpM8A@mail.gmail.com>
 <202401241348.1A2860EB58@keescook>
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
In-Reply-To: <202401241348.1A2860EB58@keescook>
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On 2024/01/25 6:50, Kees Cook wrote:
> Yeah, I was just noticing this. I was over thinking. :) It does look
> like all that is needed is to remove __FMODE_EXEC.

I worry that some out-of-tree kernel code continues using __FMODE_EXEC for
opening for non-execve() purpose. If that happened, TOMOYO will be fooled...
Can't we remove __FMODE_EXEC and FMODE_EXEC flag from f_flags instead of
replacing current->in_execve with file->f_flags & __FMODE_EXEC ?