linux-kernel - Re: [PATCH v6] ima: move APPRAISE_BOOTPARAM dependency on ARCH

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Message-ID: <d337cbba-e996-e898-1e75-9f142d480e5e@linux.vnet.ibm.com>
Date:   Mon, 20 Jul 2020 10:40:29 -0400
From:   Nayna <nayna@...ux.vnet.ibm.com>
To:     Bruno Meneguele <bmeneg@...hat.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-integrity@...r.kernel.org,
        zohar@...ux.ibm.com
Cc:     erichte@...ux.ibm.com, nayna@...ux.ibm.com, stable@...r.kernel.org
Subject: Re: [PATCH v6] ima: move APPRAISE_BOOTPARAM dependency on ARCH_POLICY
 to runtime


On 7/13/20 12:48 PM, Bruno Meneguele wrote:
> The IMA_APPRAISE_BOOTPARAM config allows enabling different "ima_appraise="
> modes - log, fix, enforce - at run time, but not when IMA architecture
> specific policies are enabled.  This prevents properly labeling the
> filesystem on systems where secure boot is supported, but not enabled on the
> platform.  Only when secure boot is actually enabled should these IMA
> appraise modes be disabled.
>
> This patch removes the compile time dependency and makes it a runtime
> decision, based on the secure boot state of that platform.
>
> Test results as follows:
>
> -> x86-64 with secure boot enabled
>
> [    0.015637] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix
> [    0.015668] ima: Secure boot enabled: ignoring ima_appraise=fix boot parameter option
>
> -> powerpc with secure boot disabled
>
> [    0.000000] Kernel command line: <...> ima_policy=appraise_tcb ima_appraise=fix
> [    0.000000] Secure boot mode disabled
>
> -> Running the system without secure boot and with both options set:
>
> CONFIG_IMA_APPRAISE_BOOTPARAM=y
> CONFIG_IMA_ARCH_POLICY=y
>
> Audit prompts "missing-hash" but still allow execution and, consequently,
> filesystem labeling:
>
> type=INTEGRITY_DATA msg=audit(07/09/2020 12:30:27.778:1691) : pid=4976
> uid=root auid=root ses=2
> subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 op=appraise_data
> cause=missing-hash comm=bash name=/usr/bin/evmctl dev="dm-0" ino=493150
> res=no
>
> Cc: stable@...r.kernel.org
> Fixes: d958083a8f64 ("x86/ima: define arch_get_ima_policy() for x86")
> Signed-off-by: Bruno Meneguele <bmeneg@...hat.com>


Reviewed-by: Nayna Jain<nayna@...ux.ibm.com>

Tested-by: Nayna Jain<nayna@...ux.ibm.com>


Thanks & Regards,

         - Nayna