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From: Matthew Garrett <mjg59@google.com>
To: Dave Young <dyoung@redhat.com>
Cc: James Morris <jmorris@namei.org>, Jiri Bohac <jbohac@suse.cz>,
	Linux API <linux-api@vger.kernel.org>,
	kexec@lists.infradead.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	David Howells <dhowells@redhat.com>,
	LSM List <linux-security-module@vger.kernel.org>,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH V31 07/25] kexec_file: Restrict at runtime if the kernel is locked down
Date: Fri, 21 Jun 2019 13:18:03 -0700	[thread overview]
Message-ID: <CACdnJut=J1YTpM4s6g5XWCEs+=X0Jvf8otfMg+w=_oqSZmf01Q@mail.gmail.com> (raw)
In-Reply-To: <20190621064340.GB4528@localhost.localdomain>

On Thu, Jun 20, 2019 at 11:43 PM Dave Young <dyoung@redhat.com> wrote:
>
> On 03/26/19 at 11:27am, Matthew Garrett wrote:
> > From: Jiri Bohac <jbohac@suse.cz>
> >
> > When KEXEC_SIG is not enabled, kernel should not load images through
> > kexec_file systemcall if the kernel is locked down.
> >
> > [Modified by David Howells to fit with modifications to the previous patch
> >  and to return -EPERM if the kernel is locked down for consistency with
> >  other lockdowns. Modified by Matthew Garrett to remove the IMA
> >  integration, which will be replaced by integrating with the IMA
> >  architecture policy patches.]
> >
> > Signed-off-by: Jiri Bohac <jbohac@suse.cz>
> > Signed-off-by: David Howells <dhowells@redhat.com>
> > Signed-off-by: Matthew Garrett <mjg59@google.com>
> > Reviewed-by: Jiri Bohac <jbohac@suse.cz>
> > cc: kexec@lists.infradead.org
> > ---
> >  kernel/kexec_file.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> > index 67f3a866eabe..a1cc37c8b43b 100644
> > --- a/kernel/kexec_file.c
> > +++ b/kernel/kexec_file.c
> > @@ -239,6 +239,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
> >               }
> >
> >               ret = 0;
> > +
> > +             if (kernel_is_locked_down(reason, LOCKDOWN_INTEGRITY)) {
> > +                     ret = -EPERM;
> > +                     goto out;
> > +             }
> > +
>
> Checking here is late, it would be good to move the check to earlier
> code around below code:
>         /* We only trust the superuser with rebooting the system. */
>         if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
>                 return -EPERM;

I don't think so - we want it to be possible to load images if they
have a valid signature.

  reply	other threads:[~2019-06-21 20:18 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-26 18:27 [PATCH V31 00/25] Add support for kernel lockdown Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 01/25] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 02/25] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 03/25] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 04/25] kexec_load: Disable at runtime if " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 05/25] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 06/25] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-06-21  6:34   ` Dave Young
2019-06-21 20:13     ` Matthew Garrett
2019-06-21 20:14       ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 07/25] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-06-21  6:43   ` Dave Young
2019-06-21 20:18     ` Matthew Garrett [this message]
2019-06-24  1:52       ` Dave Young
2019-06-24 21:06         ` Matthew Garrett
2019-06-24 21:27           ` Mimi Zohar
2019-06-25  0:02             ` Matthew Garrett
2019-06-25  1:46               ` Mimi Zohar
2019-06-25  2:51           ` Dave Young
2019-03-26 18:27 ` [PATCH V31 08/25] hibernate: Disable when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 09/25] uswsusp: " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 10/25] PCI: Lock down BAR access " Matthew Garrett
2019-03-26 20:55   ` Andy Lutomirski
2019-03-26 21:19     ` Alex Williamson
2019-03-26 18:27 ` [PATCH V31 11/25] x86: Lock down IO port " Matthew Garrett
2019-03-26 20:56   ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 12/25] x86/msr: Restrict MSR " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 13/25] ACPI: Limit access to custom_method " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 15/25] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 16/25] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 17/25] Lock down TIOCSSERIAL Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 18/25] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 19/25] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-03-27 15:57   ` Steven Rostedt
2019-03-27 16:55     ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 20/25] Lock down /proc/kcore Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 21/25] Lock down kprobes when in confidentiality mode Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 22/25] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-03-26 19:21   ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 23/25] Lock down perf when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 24/25] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 25/25] debugfs: Disable open() when kernel is locked down Matthew Garrett
2019-03-26 19:20   ` Andy Lutomirski
2019-03-26 19:21     ` Matthew Garrett
2019-03-27  0:30     ` Greg KH
2019-03-27  4:29       ` Andy Lutomirski
2019-03-27  5:06         ` Greg KH
2019-03-27  5:29           ` Andy Lutomirski
2019-03-27  5:33             ` Greg KH
2019-03-27 16:53               ` James Morris
2019-03-27 17:39               ` Andy Lutomirski
2019-03-27 17:42                 ` Matthew Garrett
2019-03-27 18:29                   ` Greg KH
2019-03-27 18:31                 ` Greg KH
2019-03-27  0:31   ` Greg KH
2019-03-27  2:06     ` Matthew Garrett
2019-03-27  2:35       ` Greg KH

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