From: David Howells <dhowells@redhat.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org,
linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk,
netdev@vger.kernel.org, Chun-Yi Lee <jlee@suse.com>,
linux-security-module@vger.kernel.org, keyrings@vger.kernel.org,
gregkh@linuxfoundation.org, matthew.garrett@nebula.com
Subject: Re: [PATCH 20/24] bpf: Restrict kernel image access functions when the kernel is locked down
Date: Thu, 13 Apr 2017 09:46:18 +0100 [thread overview]
Message-ID: <15283.1492073178@warthog.procyon.org.uk> (raw)
In-Reply-To: <20170406122907.GA53880@ast-mbp.thefacebook.com>
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> this will obviously break the program.
Yeah. But if it allows one to twiddle the kernel image or gain access to
crypto material...
> How about disabling loading tracing programs during the lockdown completely?
Interesting thought. I'm not sure how much would actually need locking down
here. Turning on tracepoints in the kernel and reading out of the trace
buffer, for example, ought to be okay, though if there are any tracepoints
that leak crypto information, they may need locking down also.
Basically, I think it boils down to: if it can be used to modify the kernel
image or read arbitrary data from the kernel image then should probably be
forbidden. There have to be exceptions, though, such as loading authenticated
kernel modules.
David
WARNING: multiple messages have this Message-ID (diff)
From: dhowells@redhat.com (David Howells)
To: linux-security-module@vger.kernel.org
Subject: [PATCH 20/24] bpf: Restrict kernel image access functions when the kernel is locked down
Date: Thu, 13 Apr 2017 09:46:18 +0100 [thread overview]
Message-ID: <15283.1492073178@warthog.procyon.org.uk> (raw)
In-Reply-To: <20170406122907.GA53880@ast-mbp.thefacebook.com>
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> this will obviously break the program.
Yeah. But if it allows one to twiddle the kernel image or gain access to
crypto material...
> How about disabling loading tracing programs during the lockdown completely?
Interesting thought. I'm not sure how much would actually need locking down
here. Turning on tracepoints in the kernel and reading out of the trace
buffer, for example, ought to be okay, though if there are any tracepoints
that leak crypto information, they may need locking down also.
Basically, I think it boils down to: if it can be used to modify the kernel
image or read arbitrary data from the kernel image then should probably be
forbidden. There have to be exceptions, though, such as loading authenticated
kernel modules.
David
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next prev parent reply other threads:[~2017-04-13 8:46 UTC|newest]
Thread overview: 211+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 20:14 [PATCH 00/24] Kernel lockdown David Howells
2017-04-05 20:14 ` David Howells
2017-04-05 20:14 ` [PATCH 01/24] efi: Add EFI_SECURE_BOOT bit David Howells
2017-04-05 20:14 ` David Howells
2017-04-06 8:26 ` Ard Biesheuvel
2017-04-06 8:26 ` Ard Biesheuvel
2017-04-06 8:48 ` David Howells
2017-04-06 8:48 ` David Howells
2017-04-05 20:14 ` [PATCH 02/24] Add the ability to lock down access to the running kernel image David Howells
2017-04-05 20:14 ` David Howells
2017-04-05 20:14 ` David Howells
2017-04-05 20:14 ` [PATCH 03/24] efi: Lock down the kernel if booted in secure boot mode David Howells
2017-04-05 20:14 ` David Howells
2017-04-05 20:15 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` [PATCH 05/24] Restrict /dev/mem and /dev/kmem when " David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` [PATCH 06/24] Add a sysrq option to exit secure boot mode David Howells
2017-04-05 20:15 ` David Howells
2017-04-14 18:05 ` Thomas Gleixner
2017-04-14 18:05 ` Thomas Gleixner
2017-04-14 18:05 ` Thomas Gleixner
2017-04-14 18:15 ` Ard Biesheuvel
2017-04-14 18:15 ` Ard Biesheuvel
2017-04-14 18:15 ` Ard Biesheuvel
2017-04-14 23:16 ` David Howells
2017-04-14 23:16 ` David Howells
2017-04-14 23:16 ` David Howells
2017-04-16 20:46 ` Matt Fleming
2017-04-16 20:46 ` Matt Fleming
2017-04-16 20:46 ` Matt Fleming
2017-04-05 20:15 ` [PATCH 07/24] kexec: Disable at runtime if the kernel is locked down David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` David Howells
2017-04-07 3:07 ` Dave Young
2017-04-07 3:07 ` Dave Young
2017-04-07 3:07 ` Dave Young
2017-04-07 3:07 ` Dave Young
2017-04-05 20:15 ` [PATCH 08/24] Copy secure_boot flag in boot params across kexec reboot David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` David Howells
2017-04-05 20:15 ` David Howells
2017-04-07 3:05 ` Dave Young
2017-04-07 3:05 ` Dave Young
2017-04-07 3:05 ` Dave Young
2017-04-07 3:05 ` Dave Young
2017-04-07 3:49 ` Mimi Zohar
2017-04-07 3:49 ` Mimi Zohar
2017-04-07 3:49 ` Mimi Zohar
2017-04-07 6:19 ` Dave Young
2017-04-07 6:19 ` Dave Young
2017-04-07 6:19 ` Dave Young
2017-04-07 6:19 ` Dave Young
2017-04-07 7:45 ` Mimi Zohar
2017-04-07 7:45 ` Mimi Zohar
2017-04-07 7:45 ` Mimi Zohar
2017-04-07 8:01 ` Dave Young
2017-04-07 8:01 ` Dave Young
2017-04-07 8:01 ` Dave Young
2017-04-07 7:07 ` David Howells
2017-04-07 7:07 ` David Howells
2017-04-07 7:07 ` David Howells
2017-04-07 7:41 ` Dave Young
2017-04-07 7:41 ` Dave Young
2017-04-07 7:41 ` Dave Young
2017-04-07 7:41 ` Dave Young
2017-04-07 8:28 ` Mimi Zohar
2017-04-07 8:28 ` Mimi Zohar
2017-04-07 8:28 ` Mimi Zohar
2017-04-07 8:28 ` Mimi Zohar
2017-04-07 8:42 ` Dave Young
2017-04-07 8:42 ` Dave Young
2017-04-07 8:42 ` Dave Young
2017-04-07 8:42 ` Dave Young
2017-04-07 7:09 ` David Howells
2017-04-07 7:09 ` David Howells
2017-04-07 7:09 ` David Howells
2017-04-07 7:46 ` Mimi Zohar
2017-04-07 7:46 ` Mimi Zohar
2017-04-07 7:46 ` Mimi Zohar
2017-04-07 9:17 ` David Howells
2017-04-07 9:17 ` David Howells
2017-04-07 9:17 ` David Howells
2017-04-07 12:36 ` Mimi Zohar
2017-04-07 12:36 ` Mimi Zohar
2017-04-07 12:36 ` Mimi Zohar
2017-04-10 13:19 ` David Howells
2017-04-10 13:19 ` David Howells
2017-04-10 13:19 ` David Howells
2017-05-02 19:01 ` Mimi Zohar
2017-05-02 19:01 ` Mimi Zohar
2017-05-02 19:01 ` Mimi Zohar
2017-05-02 19:01 ` Mimi Zohar
2017-04-05 20:16 ` [PATCH 10/24] hibernate: Disable when the kernel is locked down David Howells
2017-04-05 20:16 ` David Howells
2017-04-05 20:16 ` [PATCH 11/24] uswsusp: " David Howells
2017-04-05 20:16 ` David Howells
2017-04-05 23:38 ` Rafael J. Wysocki
2017-04-05 23:38 ` Rafael J. Wysocki
2017-04-05 23:38 ` Rafael J. Wysocki
2017-04-06 6:39 ` Oliver Neukum
2017-04-06 6:39 ` Oliver Neukum
2017-04-06 8:41 ` David Howells
2017-04-06 8:41 ` David Howells
2017-04-06 20:09 ` Rafael J. Wysocki
2017-04-06 20:09 ` Rafael J. Wysocki
2017-04-06 20:09 ` Rafael J. Wysocki
2017-04-06 20:12 ` Rafael J. Wysocki
2017-04-06 20:12 ` Rafael J. Wysocki
2017-04-06 20:25 ` Jiri Kosina
2017-04-06 20:25 ` Jiri Kosina
2017-04-08 3:28 ` poma
2017-04-08 3:28 ` poma
2017-04-12 13:44 ` joeyli
2017-04-12 13:44 ` joeyli
2017-04-06 6:55 ` David Howells
2017-04-06 6:55 ` David Howells
2017-04-06 20:07 ` Rafael J. Wysocki
2017-04-06 20:07 ` Rafael J. Wysocki
2017-04-05 20:16 ` [PATCH 12/24] PCI: Lock down BAR access " David Howells
2017-04-05 20:16 ` David Howells
2017-04-18 17:50 ` Bjorn Helgaas
2017-04-18 17:50 ` Bjorn Helgaas
2017-04-18 17:50 ` Bjorn Helgaas
2017-04-05 20:16 ` [PATCH 13/24] x86: Lock down IO port " David Howells
2017-04-05 20:16 ` David Howells
2017-04-05 20:16 ` David Howells
2017-04-14 18:28 ` Thomas Gleixner
2017-04-14 18:28 ` Thomas Gleixner
2017-04-14 18:28 ` Thomas Gleixner
2017-04-05 20:16 ` [PATCH 14/24] x86: Restrict MSR " David Howells
2017-04-05 20:16 ` David Howells
2017-04-14 18:30 ` Thomas Gleixner
2017-04-14 18:30 ` Thomas Gleixner
2017-04-05 20:16 ` [PATCH 15/24] asus-wmi: Restrict debugfs interface " David Howells
2017-04-05 20:16 ` David Howells
2017-04-07 10:25 ` Andy Shevchenko
2017-04-07 10:25 ` Andy Shevchenko
2017-04-07 12:50 ` David Howells
2017-04-07 12:50 ` David Howells
2017-04-09 11:10 ` Andy Shevchenko
2017-04-09 11:10 ` Andy Shevchenko
2017-04-10 13:16 ` David Howells
2017-04-10 13:16 ` David Howells
2017-04-18 6:06 ` Andy Shevchenko
2017-04-18 6:06 ` Andy Shevchenko
2017-04-18 6:06 ` Andy Shevchenko
2017-04-18 14:34 ` Ben Hutchings
2017-04-18 14:34 ` Ben Hutchings
2017-04-18 14:55 ` David Howells
2017-04-18 14:55 ` David Howells
2017-04-18 14:55 ` David Howells
2017-04-18 15:19 ` Ben Hutchings
2017-04-18 15:19 ` Ben Hutchings
2017-04-18 15:34 ` David Howells
2017-04-18 15:34 ` David Howells
2017-04-18 15:34 ` David Howells
2017-04-18 15:30 ` David Howells
2017-04-18 15:30 ` David Howells
2017-04-18 17:39 ` Ben Hutchings
2017-04-18 17:39 ` Ben Hutchings
2017-04-18 17:39 ` Ben Hutchings
2017-04-05 20:16 ` [PATCH 16/24] ACPI: Limit access to custom_method " David Howells
2017-04-05 20:16 ` David Howells
2017-04-05 20:16 ` [PATCH 17/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2017-04-05 20:16 ` David Howells
2017-04-06 19:43 ` Rafael J. Wysocki
2017-04-06 19:43 ` Rafael J. Wysocki
2017-04-07 6:31 ` Dave Young
2017-04-07 6:31 ` Dave Young
[not found] ` <20170407063107.GA10451-0VdLhd/A9Pl+NNSt+8eSiB/sF2h8X+2i0E9HWUfgJXw@public.gmane.org>
2017-04-07 7:05 ` David Howells
2017-04-07 7:05 ` David Howells
2017-04-07 7:05 ` David Howells
2017-04-07 7:39 ` Dave Young
2017-04-07 7:39 ` Dave Young
2017-04-05 20:17 ` [PATCH 18/24] acpi: Disable ACPI table override if the kernel is " David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` [PATCH 19/24] acpi: Disable APEI error injection " David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` [PATCH 20/24] bpf: Restrict kernel image access functions when " David Howells
2017-04-05 20:17 ` David Howells
2017-04-06 12:29 ` Alexei Starovoitov
2017-04-06 12:29 ` Alexei Starovoitov
2017-04-06 12:40 ` Ard Biesheuvel
2017-04-06 12:40 ` Ard Biesheuvel
2017-04-12 14:57 ` joeyli
2017-04-12 14:57 ` joeyli
2017-04-12 14:57 ` joeyli
2017-04-13 8:46 ` David Howells [this message]
2017-04-13 8:46 ` David Howells
2017-04-05 20:17 ` [PATCH 21/24] scsi: Lock down the eata driver David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` [PATCH 22/24] Prohibit PCMCIA CIS storage when the kernel is locked down David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` [PATCH 23/24] Lock down TIOCSSERIAL David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:17 ` David Howells
2017-04-05 20:18 ` [PATCH 24/24] Lock down module params that specify hardware parameters (eg. ioport) David Howells
2017-04-05 20:18 ` David Howells
2017-04-05 20:18 ` David Howells
2017-04-07 15:59 ` [PATCH 00/24] Kernel lockdown Austin S. Hemmelgarn
2017-04-07 15:59 ` Austin S. Hemmelgarn
2017-04-07 16:29 ` Justin Forbes
2017-04-07 16:29 ` Justin Forbes
2017-04-07 16:29 ` Justin Forbes
2017-04-10 23:15 ` Why kernel lockdown? David Howells
2017-04-10 23:15 ` David Howells
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