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Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set

From Mimi Zohar <zohar@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set
Date 2017-04-07 05:50 +0200
Message-ID <ttt4m-1IG-3@gated-at.bofh.it> (permalink)
References <tsZzj-7hF-5@gated-at.bofh.it> <tsZJ0-7kG-7@gated-at.bofh.it> <ttsrD-1tz-1@gated-at.bofh.it>
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On Fri, 2017-04-07 at 11:05 +0800, Dave Young wrote:
> On 04/05/17 at 09:15pm, David Howells wrote:
> > From: Chun-Yi Lee <joeyli.kernel@gmail.com>
> > 
> > When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image
> > through kexec_file systemcall if securelevel has been set.
> > 
> > This code was showed in Matthew's patch but not in git:
> > https://lkml.org/lkml/2015/3/13/778
> > 
> > Cc: Matthew Garrett <mjg59@srcf.ucam.org>
> > Signed-off-by: Chun-Yi Lee <jlee@suse.com>
> > Signed-off-by: David Howells <dhowells@redhat.com>
> > 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 b118735fea9d..f6937eecd1eb 100644
> > --- a/kernel/kexec_file.c
> > +++ b/kernel/kexec_file.c
> > @@ -268,6 +268,12 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
> >  	if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
> >  		return -EPERM;
> >  
> > +	/* Don't permit images to be loaded into trusted kernels if we're not
> > +	 * going to verify the signature on them
> > +	 */
> > +	if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && kernel_is_locked_down())
> > +		return -EPERM;
> > +
> >  

IMA can be used to verify file signatures too, based on the LSM hooks
in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be
required.

Mimi


> 	/* Make sure we have a legal set of flags */
> >  	if (flags != (flags & KEXEC_FILE_FLAGS))
> >  		return -EINVAL;
> > 
> > 
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
> 
> Acked-by: Dave Young <dyoung@redhat.com>
> 
> Thanks
> Dave
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo@vger.kernel.org
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>

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Thread

[PATCH 00/24] Kernel lockdown David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 24/24] Lock down module params that specify hardware  parameters (eg. ioport) David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 03/24] efi: Lock down the kernel if booted in secure boot  mode David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 20/24] bpf: Restrict kernel image access functions when the  kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
    Re: [PATCH 20/24] bpf: Restrict kernel image access functions when  the kernel is locked down Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2017-04-06 14:30 +0200
      Re: [PATCH 20/24] bpf: Restrict kernel image access functions when  the kernel is locked down Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-04-06 14:50 +0200
  [PATCH 12/24] PCI: Lock down BAR access when the kernel is locked  down David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 15/24] asus-wmi: Restrict debugfs interface when the kernel  is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
    Re: [PATCH 15/24] asus-wmi: Restrict debugfs interface when the  kernel is locked down Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-07 12:30 +0200
      Re: [PATCH 15/24] asus-wmi: Restrict debugfs interface when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-07 15:00 +0200
        Re: [PATCH 15/24] asus-wmi: Restrict debugfs interface when the  kernel is locked down Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-04-09 13:20 +0200
          Re: [PATCH 15/24] asus-wmi: Restrict debugfs interface when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-10 15:20 +0200
  [PATCH 02/24] Add the ability to lock down access to the running  kernel image David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 07/24] kexec: Disable at runtime if the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
    Re: [PATCH 07/24] kexec: Disable at runtime if the kernel is locked  down Dave Young <dyoung@redhat.com> - 2017-04-07 05:10 +0200
  [PATCH 08/24] Copy secure_boot flag in boot params across kexec  reboot David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 06/24] Add a sysrq option to exit secure boot mode David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 10/24] hibernate: Disable when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:20 +0200
  [PATCH 14/24] x86: Restrict MSR access when the kernel is locked  down David Howells <dhowells@redhat.com> - 2017-04-05 22:30 +0200
  [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:30 +0200
  [PATCH 11/24] uswsusp: Disable when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-05 22:30 +0200
    Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-06 01:40 +0200
      Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down Oliver Neukum <oneukum@suse.com> - 2017-04-06 08:50 +0200
        Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-06 11:30 +0200
          Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-06 22:20 +0200
            Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down Jiri Kosina <jikos@kernel.org> - 2017-04-06 22:30 +0200
              Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down poma <pomidorabelisima@gmail.com> - 2017-04-08 05:30 +0200
          Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-06 22:20 +0200
      Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down David Howells <dhowells@redhat.com> - 2017-04-06 09:00 +0200
        Re: [PATCH 11/24] uswsusp: Disable when the kernel is locked down "Rafael J. Wysocki" <rafael@kernel.org> - 2017-04-06 22:20 +0200
  [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set David Howells <dhowells@redhat.com> - 2017-04-05 22:30 +0200
    Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Dave Young <dyoung@redhat.com> - 2017-04-07 05:10 +0200
      Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-04-07 05:50 +0200
        Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Dave Young <dyoung@redhat.com> - 2017-04-07 08:20 +0200
          Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells <dhowells@redhat.com> - 2017-04-07 09:10 +0200
            Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Dave Young <dyoung@redhat.com> - 2017-04-07 09:50 +0200
              Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-04-07 10:30 +0200
                Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Dave Young <dyoung@redhat.com> - 2017-04-07 10:50 +0200
          Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-04-07 09:50 +0200
            Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Dave Young <dyoung@redhat.com> - 2017-04-07 10:10 +0200
        Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells <dhowells@redhat.com> - 2017-04-07 09:20 +0200
          Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-04-07 09:50 +0200
            Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells <dhowells@redhat.com> - 2017-04-07 11:20 +0200
              Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has  been set Mimi Zohar <zohar@linux.vnet.ibm.com> - 2017-04-07 14:40 +0200
                Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells <dhowells@redhat.com> - 2017-04-10 15:30 +0200
  Re: [PATCH 00/24] Kernel lockdown "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2017-04-07 18:10 +0200
    Re: [PATCH 00/24] Kernel lockdown Justin Forbes <jmforbes@linuxtx.org> - 2017-04-07 18:40 +0200

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