Re: [PATCH v6] ima: move APPRAISE_BOOTPARAM dependency on ARCH_POLICY to runtime

[Nayna <nayna@linux.vnet.ibm.com>]

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@vger.kernel.org
> Fixes: d958083a8f64 ("x86/ima: define arch_get_ima_policy() for x86")
> Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>


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

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


Thanks & Regards,

         - Nayna