From: David Howells <dhowells@redhat.com>
To: Jann Horn <jannh@google.com>
Cc: dhowells@redhat.com, Alexei Starovoitov <ast@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Matthew Garrett <mjg59@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
James Morris <jmorris@namei.org>,
Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Justin Forbes <jforbes@redhat.com>,
linux-man <linux-man@vger.kernel.org>, joeyli <jlee@suse.com>,
LSM List <linux-security-module@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
linux-efi <linux-efi@vger.kernel.org>
Subject: Re: An actual suggestion (Re: [GIT PULL] Kernel lockdown for secure boot)
Date: Wed, 04 Apr 2018 23:19:27 +0100 [thread overview]
Message-ID: <15406.1522880367@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAG48ez3edmZo1iFXqpvzOKNY0jLzcqa18KuoRrBaPyfp=7huZQ@mail.gmail.com>
Jann Horn <jannh@google.com> wrote:
> > Uh, no. bpf, for example, can be used to modify kernel memory.
>
> I'm pretty sure bpf isn't supposed to be able to modify arbitrary
> kernel memory. AFAIU if you can use BPF to write to arbitrary kernel
> memory, that's a bug; with CAP_SYS_ADMIN, you can read from userspace,
> write to userspace, and read from kernelspace, but you shouldn't be
> able to write to kernelspace.
Ah - you may be right. I seem to have misremembered what Joey Lee wrote in
his patch description.
David
next prev parent reply other threads:[~2018-04-04 22:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-04 14:49 An actual suggestion (Re: [GIT PULL] Kernel lockdown for secure boot) Andy Lutomirski
2018-04-04 16:17 ` David Howells
2018-04-04 16:23 ` Jann Horn
2018-04-04 22:19 ` David Howells [this message]
2018-04-05 1:48 ` joeyli
2018-04-04 16:36 ` Andy Lutomirski
2018-04-04 23:25 ` James Morris
2018-04-05 0:22 ` Matthew Garrett
2018-04-05 2:16 ` joeyli
2018-04-05 14:01 ` Mimi Zohar
2018-04-05 16:11 ` jlee
2018-04-05 1:45 ` joeyli
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