Re: linux-next: Tree for Apr 16 (IMA appraise causing build error)

Re: linux-next: Tree for Apr 16 (IMA appraise causing build error)

[Randy Dunlap]

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On 4/16/21 4:36 AM, Stephen Rothwell wrote:
> Hi all,
> 
> Changes since 20210415:
> 

I noticed this build error message (on an i386 build):

../certs/Makefile:52: *** Could not determine digest type to use from kernel config.  Stop.

and when I was checking on why it happened, I noticed that
# CONFIG_MODULES is not set

and hence
ifndef CONFIG_MODULE_SIG_HASH
$(error Could not determine digest type to use from kernel config)
endif

CONFIG_MODULE_SIG_HASH is not set/enabled/defined.

However, the .config file does have
CONFIG_IMA_APPRAISE=y
# CONFIG_IMA_ARCH_POLICY is not set
# CONFIG_IMA_APPRAISE_BUILD_POLICY is not set
CONFIG_IMA_APPRAISE_BOOTPARAM=y
CONFIG_IMA_APPRAISE_MODSIG=y

as well as
CONFIG_MODULE_SIG_FORMAT=y

due to a "select" by IMA_APPRAISE_MODSIG.
(although I see that MODULE_SIG_FORMAT does not depend on MODULES)


Is there anything that you can do (or recommend) to prevent
the build error?



BTW, it looks like this:
config IMA_APPRAISE_REQUIRE_MODULE_SIGS
	bool "Appraise kernel modules signatures"
	depends on IMA_APPRAISE_BUILD_POLICY

could also depend on MODULES.



Full i386 randconfig file is attached.

thanks.
-- 
~Randy
Reported-by: Randy Dunlap <rdunlap@infradead.org>

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Re: linux-next: Tree for Apr 16 (IMA appraise causing build error)

[Nayna]

On 4/16/21 2:53 PM, Randy Dunlap wrote:
> On 4/16/21 4:36 AM, Stephen Rothwell wrote:
>> Hi all,
>>
>> Changes since 20210415:
>>
> I noticed this build error message (on an i386 build):
>
> ../certs/Makefile:52: *** Could not determine digest type to use from kernel config.  Stop.
>
> and when I was checking on why it happened, I noticed that
> # CONFIG_MODULES is not set
>
> and hence
> ifndef CONFIG_MODULE_SIG_HASH
> $(error Could not determine digest type to use from kernel config)
> endif
>
> CONFIG_MODULE_SIG_HASH is not set/enabled/defined.
>
> However, the .config file does have
> CONFIG_IMA_APPRAISE=y
> # CONFIG_IMA_ARCH_POLICY is not set
> # CONFIG_IMA_APPRAISE_BUILD_POLICY is not set
> CONFIG_IMA_APPRAISE_BOOTPARAM=y
> CONFIG_IMA_APPRAISE_MODSIG=y
>
> as well as
> CONFIG_MODULE_SIG_FORMAT=y
>
> due to a "select" by IMA_APPRAISE_MODSIG.
> (although I see that MODULE_SIG_FORMAT does not depend on MODULES)
>
>
> Is there anything that you can do (or recommend) to prevent
> the build error?
>
>
>
> BTW, it looks like this:
> config IMA_APPRAISE_REQUIRE_MODULE_SIGS
> 	bool "Appraise kernel modules signatures"
> 	depends on IMA_APPRAISE_BUILD_POLICY
>
> could also depend on MODULES.
>
>
>
> Full i386 randconfig file is attached.


With the new patchset "ima: kernel build support for loading the kernel 
module signing key", there shouldn't be a difference when generating the 
config file between MODULE_SIG and IMA_APPRAISE_MODSIG. Both prompt for 
the hash algorithm.

Can you please explain how you generate randconfig? Do you use make xconfig?

Thanks & Regards,

     - Nayna

Re: linux-next: Tree for Apr 16 (IMA appraise causing build error)

[Randy Dunlap]

Hi,

On 4/16/21 1:25 PM, Nayna wrote:
> 
> On 4/16/21 2:53 PM, Randy Dunlap wrote:
>> On 4/16/21 4:36 AM, Stephen Rothwell wrote:
>>> Hi all,
>>>
>>> Changes since 20210415:
>>>
>> I noticed this build error message (on an i386 build):
>>
>> ../certs/Makefile:52: *** Could not determine digest type to use from kernel config.  Stop.
>>
>> and when I was checking on why it happened, I noticed that
>> # CONFIG_MODULES is not set
>>
>> and hence
>> ifndef CONFIG_MODULE_SIG_HASH
>> $(error Could not determine digest type to use from kernel config)
>> endif
>>
>> CONFIG_MODULE_SIG_HASH is not set/enabled/defined.
>>
>> However, the .config file does have
>> CONFIG_IMA_APPRAISE=y
>> # CONFIG_IMA_ARCH_POLICY is not set
>> # CONFIG_IMA_APPRAISE_BUILD_POLICY is not set
>> CONFIG_IMA_APPRAISE_BOOTPARAM=y
>> CONFIG_IMA_APPRAISE_MODSIG=y
>>
>> as well as
>> CONFIG_MODULE_SIG_FORMAT=y
>>
>> due to a "select" by IMA_APPRAISE_MODSIG.
>> (although I see that MODULE_SIG_FORMAT does not depend on MODULES)
>>
>>
>> Is there anything that you can do (or recommend) to prevent
>> the build error?
>>
>>
>>
>> BTW, it looks like this:
>> config IMA_APPRAISE_REQUIRE_MODULE_SIGS
>>     bool "Appraise kernel modules signatures"
>>     depends on IMA_APPRAISE_BUILD_POLICY
>>
>> could also depend on MODULES.
>>
>>
>>
>> Full i386 randconfig file is attached.
> 
> 
> With the new patchset "ima: kernel build support for loading the kernel module signing key", there shouldn't be a difference when generating the config file between MODULE_SIG and IMA_APPRAISE_MODSIG. Both prompt for the hash algorithm.

That patchset appears to be included in today's linux-next 2021-04-16.

> Can you please explain how you generate randconfig? Do you use make xconfig?

with the 'make randconfig' command.


-- 
~Randy