From: jikos@kernel.org (Jiri Kosina)
To: linux-security-module@vger.kernel.org
Subject: [PATCH 26/30] Lock down ftrace
Date: Fri, 10 Nov 2017 10:23:19 +0100 (CET) [thread overview]
Message-ID: <alpine.LRH.2.00.1711101021440.24296@gjva.wvxbf.pm> (raw)
In-Reply-To: <151024883613.28329.14808632296386937974.stgit@warthog.procyon.org.uk>
On Thu, 9 Nov 2017, David Howells wrote:
> Disallow the use of ftrace when the kernel is locked down. This patch
> turns off ftrace_enabled late in the kernel boot so that the selftest can
> still be potentially be run.
>
> The sysctl that controls ftrace_enables is also disallowed when the kernel
> is locked down. If the lockdown is lifted, then the sysctl can be used to
> reenable ftrace - if ftrace was compiled with CONFIG_DYNAMIC_FTRACE, that
> is; if it wasn't then it won't be possible to reenable it.
>
> This prevents crypto data theft by analysis of execution patterns, and, if
> in future ftrace also logs the register contents at the time, will prevent
> data theft by that mechanism also.
I fail to see how this fits into the secure boot security model, could you
please explain?
Secure boot is about having a constant proof / verification that the code
you're running in ring0 can be trusted (IOW is the one that has been
signed and verified by the whole boot chain).
Checking execution patterns doesn't seem to fit at all.
Thanks,
--
Jiri Kosina
SUSE Labs
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next prev parent reply other threads:[~2017-11-10 9:23 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-09 17:30 [PATCH 00/30] security, efi: Add kernel lockdown David Howells
2017-11-09 17:30 ` [PATCH 01/30] Add the ability to lock down access to the running kernel image David Howells
2017-11-09 17:30 ` [PATCH 02/30] Add a SysRq option to lift kernel lockdown David Howells
2017-11-09 17:31 ` [PATCH 03/30] ima: require secure_boot rules in lockdown mode David Howells
2017-11-09 17:31 ` [PATCH 04/30] Enforce module signatures if the kernel is locked down David Howells
2017-11-09 17:31 ` [PATCH 05/30] Restrict /dev/{mem, kmem, port} when " David Howells
2017-11-09 17:31 ` [PATCH 06/30] kexec: Disable at runtime if " David Howells
2017-11-09 17:31 ` [PATCH 07/30] Copy secure_boot flag in boot params across kexec reboot David Howells
2017-11-09 17:31 ` [PATCH 08/30] kexec_file: Restrict at runtime if the kernel is locked down David Howells
2018-01-11 11:59 ` Jiri Bohac
2018-01-11 12:01 ` [PATCH 08a/30] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Jiri Bohac
2018-01-11 12:02 ` [PATCH 08b/30] kexec_file: Restrict at runtime if the kernel is locked down Jiri Bohac
2018-01-16 16:31 ` [PATCH 08a/30] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE David Howells
2018-01-16 19:39 ` Jiri Bohac
2018-01-17 16:34 ` David Howells
2018-01-19 12:54 ` Jiri Bohac
2018-02-21 16:20 ` David Howells
2018-01-11 12:43 ` [PATCH 08/30] kexec_file: Restrict at runtime if the kernel is locked down David Howells
2018-01-11 12:47 ` David Howells
2018-01-11 15:44 ` Jiri Bohac
2018-01-17 16:16 ` David Howells
2017-11-09 17:31 ` [PATCH 09/30] hibernate: Disable when " David Howells
2017-11-09 17:31 ` [PATCH 10/30] uswsusp: " David Howells
2017-11-09 17:32 ` [PATCH 11/30] PCI: Lock down BAR access " David Howells
2017-11-09 17:32 ` [PATCH 12/30] x86: Lock down IO port " David Howells
2017-11-09 17:32 ` [PATCH 13/30] x86/msr: Restrict MSR " David Howells
2017-11-09 17:32 ` [PATCH 14/30] asus-wmi: Restrict debugfs interface " David Howells
2017-11-09 17:32 ` [PATCH 15/30] ACPI: Limit access to custom_method " David Howells
2017-11-09 17:32 ` [PATCH 16/30] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells
2017-11-09 17:32 ` [PATCH 17/30] acpi: Disable ACPI table override if the kernel is " David Howells
2017-11-09 17:32 ` [PATCH 18/30] acpi: Disable APEI error injection " David Howells
2019-11-07 8:21 ` Joey Lee
2022-05-28 0:11 ` joeyli
2017-11-09 17:33 ` [PATCH 19/30] scsi: Lock down the eata driver David Howells
2017-11-09 17:33 ` [PATCH 20/30] Prohibit PCMCIA CIS storage when the kernel is locked down David Howells
2017-11-09 17:33 ` [PATCH 21/30] Lock down TIOCSSERIAL David Howells
2017-11-09 17:33 ` [PATCH 22/30] Lock down module params that specify hardware parameters (eg. ioport) David Howells
2017-11-09 17:33 ` [PATCH 23/30] x86/mmiotrace: Lock down the testmmiotrace module David Howells
2017-11-09 17:33 ` [PATCH 24/30] debugfs: Disallow use of debugfs files when the kernel is locked down David Howells
2017-11-09 17:33 ` [PATCH 25/30] Lock down /proc/kcore David Howells
2017-11-09 17:33 ` [PATCH 26/30] Lock down ftrace David Howells
2017-11-10 9:23 ` Jiri Kosina [this message]
2017-11-10 10:07 ` David Howells
2017-11-10 10:15 ` Jiri Kosina
2017-11-10 10:21 ` David Howells
2017-11-10 10:23 ` Jiri Kosina
2017-11-10 11:06 ` David Howells
2017-11-09 17:34 ` [PATCH 27/30] Lock down kprobes David Howells
2017-11-09 17:34 ` [PATCH 28/30] bpf: Restrict kernel image access functions when the kernel is locked down David Howells
2017-11-09 17:34 ` [PATCH 29/30] efi: Add an EFI_SECURE_BOOT flag to indicate secure boot mode David Howells
2017-11-09 17:34 ` [PATCH 30/30] efi: Lock down the kernel if booted in " David Howells
2018-02-22 13:07 ` [PATCH 04/30] Enforce module signatures if the kernel is locked down David Howells
2018-02-22 18:44 ` Jiri Bohac
2018-02-22 14:20 ` [PATCH 08/30] kexec_file: Restrict at runtime " David Howells
2018-02-22 19:08 ` Jiri Bohac
2018-02-22 14:21 ` David Howells
2018-02-22 19:14 ` Jiri Bohac
2018-03-03 1:18 ` [PATCH 00/30] security, efi: Add kernel lockdown Andrew Morton
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