Re: [PATCH v2] Documentation: crypto: add info about "fips=" boot option

[Randy Dunlap]

On 3/29/21 10:29 PM, Eric Biggers wrote:
> On Mon, Mar 29, 2021 at 10:06:51PM -0700, Randy Dunlap wrote:
>> Having just seen a report of using "fips=1" on the kernel command line,
>> I could not find it documented anywhere, so add some help for it.
>>
>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx>
>> Cc: linux-crypto@xxxxxxxxxxxxxxx
>> Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
>> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
>> Cc: Jonathan Corbet <corbet@xxxxxxx>
>> Cc: linux-doc@xxxxxxxxxxxxxxx
>> ---
>> Updates/corrections welcome.
>>
>> v2: drop comment that "fips_enabled can cause some tests to be skipped".
>>
>>  Documentation/admin-guide/kernel-parameters.txt |   14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>>
>> --- linux-next-20210329.orig/Documentation/admin-guide/kernel-parameters.txt
>> +++ linux-next-20210329/Documentation/admin-guide/kernel-parameters.txt
>> @@ -1370,6 +1370,20 @@
>>  			See Documentation/admin-guide/sysctl/net.rst for
>>  			fb_tunnels_only_for_init_ns
>>  
>> +	fips=		Format: { 0 | 1}
>> +			Use to disable (0) or enable (1) FIPS mode.
>> +			If enabled, any process that is waiting on the
>> +			'fips_fail_notif_chain' will be notified of fips
>> +			failures.
>> +			This setting can also be modified via sysctl at
>> +			/proc/sysctl/crypto/fips_enabled, i.e.,
>> +			crypto.fips_enabled.
>> +			If fips_enabled = 1 and a test fails, it will cause a
>> +			kernel panic.
>> +			If fips_enabled = 1, RSA test requires a key size of
>> +			2K or larger.
>> +			It can also effect which ECC curve is used.
> 
> This doesn't really explain why anyone would want to give this option.
> What high-level thing is this option meant to be accomplishing?
> That's what the documentation should explain.

Yes, clearly, even to me.

But I could not find anything in the kernel source tree that would help me
explain that.  So to repeat:

>> Updates/corrections welcome.

thanks.
-- 
~Randy