From: Jann Horn <jannh@google.com>
To: Kees Cook <keescook@chromium.org>
Cc: Josh Triplett <josh@joshtriplett.org>,
Kevin Locke <kevin@kevinlocke.name>,
Linus Torvalds <torvalds@linux-foundation.org>,
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>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.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
Subject: Re: [PATCH] exec: Check __FMODE_EXEC instead of in_execve for LSMs
Date: Wed, 24 Jan 2024 20:58:55 +0100 [thread overview]
Message-ID: <CAG48ez017tTwxXbxdZ4joVDv5i8FLWEjk=K_z1Vf=pf0v1=cTg@mail.gmail.com> (raw)
In-Reply-To: <20240124192228.work.788-kees@kernel.org>
On Wed, Jan 24, 2024 at 8:22 PM Kees Cook <keescook@chromium.org> wrote:
> After commit 978ffcbf00d8 ("execve: open the executable file before
> doing anything else"), current->in_execve was no longer in sync with the
> open(). This broke AppArmor and TOMOYO which depend on this flag to
> distinguish "open" operations from being "exec" operations.
>
> Instead of moving around in_execve, switch to using __FMODE_EXEC, which
> is where the "is this an exec?" intent is stored. Note that TOMOYO still
> uses in_execve around cred handling.
I think this is wrong. When CONFIG_USELIB is enabled, the uselib()
syscall will open a file with __FMODE_EXEC but without going through
execve(). From what I can tell, there are no bprm hooks on this path.
I don't know if it _matters_ much, given that it'll only let you
read/execute stuff from files with valid ELF headers, but still.
next prev parent reply other threads:[~2024-01-24 19:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-24 19:22 Kees Cook
2024-01-24 19:39 ` Kevin Locke
2024-01-24 19:51 ` Kees Cook
2024-01-24 19:58 ` Jann Horn [this message]
2024-01-24 20:15 ` Kees Cook
2024-01-24 20:47 ` Linus Torvalds
2024-01-24 20:51 ` Jann Horn
2024-01-24 21:32 ` Kees Cook
2024-01-24 21:35 ` Kees Cook
2024-01-24 21:40 ` Jann Horn
2024-01-24 21:50 ` Kees Cook
2024-01-25 14:34 ` Tetsuo Handa
2024-01-25 14:59 ` Jann Horn
2024-01-25 16:38 ` Mickaël Salaün
2024-01-27 4:53 ` John Johansen
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