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From: Mimi Zohar <zohar@linux.ibm.com>
To: Matthew Garrett <matthewgarrett@google.com>, jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, dhowells@redhat.com
Subject: Re: [PATCH 08/27] kexec_file: Restrict at runtime if the kernel is locked down
Date: Thu, 28 Feb 2019 21:05:53 -0500
Message-ID: <1551405953.10911.281.camel@linux.ibm.com> (raw)
In-Reply-To: <20190228231203.212359-8-matthewgarrett@google.com>

Hi Jiri,

Thank you for thinking about IMA.

On Thu, 2019-02-28 at 15:11 -0800, 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 unless IMA can be used
> to validate the image.

This patch is a partial solution, but it doesn't take into account the
architecture specific or custom policies.

Mimi

> [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]
> 
> Signed-off-by: Jiri Bohac <jbohac@suse.cz>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Reviewed-by: Jiri Bohac <jbohac@suse.cz>
> Cc: Matthew Garrett <mjg59@srcf.ucam.org>
> cc: Chun-Yi Lee <jlee@suse.com>
> cc: kexec@lists.infradead.org
> ---
>  include/linux/ima.h | 6 ++++++
>  kernel/kexec_file.c | 8 ++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/include/linux/ima.h b/include/linux/ima.h
> index b5e16b8c50b7..b35ed0725a05 100644
> --- a/include/linux/ima.h
> +++ b/include/linux/ima.h
> @@ -127,4 +127,10 @@ static inline int ima_inode_removexattr(struct dentry *dentry,
>  	return 0;
>  }
>  #endif /* CONFIG_IMA_APPRAISE */
> +
> +static inline bool is_ima_kexec_appraise_enabled(void)
> +{
> +	return IS_ENABLED(CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS);
> +}
> +
>  #endif /* _LINUX_IMA_H */
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 67f3a866eabe..b4e938dff4be 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -239,6 +239,14 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
>  		}
> 
>  		ret = 0;
> +		if (is_ima_kexec_appraise_enabled())
> +			break;
> +
> +		if (kernel_is_locked_down(reason)) {
> +			ret = -EPERM;
> +			goto out;
> +		}
> +
>  		break;
> 
>  		/* All other errors are fatal, including nomem, unparseable


  reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-28 21:28 [PULL REQUEST] Lock down patches Matthew Garrett
2019-02-28 22:20 ` Mimi Zohar
2019-02-28 23:13   ` Matthew Garrett
2019-03-01  0:05     ` Mimi Zohar
2019-03-01  1:01       ` Matthew Garrett
2019-03-01  1:44         ` Mimi Zohar
2019-03-01  3:33           ` Matthew Garrett
2019-03-01  4:16             ` Mimi Zohar
2019-02-28 22:44 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 22:44   ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:10 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:10   ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:11   ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:11   ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11   ` [PATCH 03/27] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-02-28 23:11   ` [PATCH 04/27] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-02-28 23:11   ` [PATCH 05/27] kexec_load: Disable at runtime if " Matthew Garrett
2019-02-28 23:11   ` [PATCH 06/27] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-02-28 23:11   ` [PATCH 07/27] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-02-28 23:11   ` [PATCH 08/27] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-03-01  2:05     ` Mimi Zohar [this message]
2019-02-28 23:11   ` [PATCH 09/27] hibernate: Disable when " Matthew Garrett
2019-03-19 22:15     ` Pavel Machek
2019-02-28 23:11   ` [PATCH 10/27] uswsusp: " Matthew Garrett
2019-02-28 23:11   ` [PATCH 11/27] PCI: Lock down BAR access " Matthew Garrett
2019-02-28 23:11   ` [PATCH 12/27] x86: Lock down IO port " Matthew Garrett
2019-02-28 23:11   ` [PATCH 13/27] x86/msr: Restrict MSR " Matthew Garrett
2019-02-28 23:11   ` [PATCH 14/27] ACPI: Limit access to custom_method " Matthew Garrett
2019-02-28 23:11   ` [PATCH 15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-02-28 23:11   ` [PATCH 16/27] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-02-28 23:11   ` [PATCH 17/27] acpi: Disable APEI error injection " Matthew Garrett
2019-02-28 23:11   ` [PATCH 18/27] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-02-28 23:11   ` [PATCH 19/27] Lock down TIOCSSERIAL Matthew Garrett
2019-02-28 23:11   ` [PATCH 20/27] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-02-28 23:11   ` [PATCH 21/27] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-02-28 23:11   ` [PATCH 22/27] Lock down /proc/kcore Matthew Garrett
2019-02-28 23:11   ` [PATCH 23/27] Lock down kprobes Matthew Garrett
2019-02-28 23:12   ` [PATCH 24/27] bpf: Restrict kernel image access functions when the kernel is locked down Matthew Garrett
2019-02-28 23:12   ` [PATCH 25/27] Lock down perf Matthew Garrett
2019-02-28 23:12   ` [PATCH 26/27] debugfs: Restrict debugfs when the kernel is locked down Matthew Garrett
2019-02-28 23:12   ` [PATCH 27/27] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-02-28 23:24 ` [PULL REQUEST] Lock down patches Randy Dunlap
2019-03-04 22:10 ` Matthew Garrett
2019-03-06 23:58 [PULL REQUEST] Kernel lockdown patches for 5.2 Matthew Garrett
2019-03-06 23:58 ` [PATCH 08/27] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett

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