Re: [PATCH v3] net/sctp: Make sha1 as default algorithm if fips is enabled

[Ashwin Dayanand Kamat]

> On 03-Jun-2023, at 4:46 AM, Xin Long <lucien.xin@xxxxxxxxx> wrote:
> 
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> On Fri, Jun 2, 2023 at 11:15 AM Simon Horman <simon.horman@xxxxxxxxxxxx> wrote:
>> 
>> + Xin Long
>> 
>> On Thu, Jun 01, 2023 at 11:47:54PM +0530, Ashwin Dayanand Kamat wrote:
>>> MD5 is not FIPS compliant. But still md5 was used as the
>>> default algorithm for sctp if fips was enabled.
>>> Due to this, listen() system call in ltp tests was
>>> failing for sctp in fips environment, with below error message.
>>> 
>>> [ 6397.892677] sctp: failed to load transform for md5: -2
>>> 
>>> Fix is to not assign md5 as default algorithm for sctp
>>> if fips_enabled is true. Instead make sha1 as default algorithm.
>>> The issue fixes ltp testcase failure "cve-2018-5803 sctp_big_chunk"
> Hi, Ashwin,
> 
> I have the same question as Paolo about "this patch gets fips compliance
> _disabling_ the encryption", is it from any standard?
> 
> If not,  can't you fix the ltp testcase for fips environment by sysctl?
> or set 'CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1=y' instead in config.
> 
> Sorry if I don't understand this well. You're trying to avoid SCTP code
> calling crypto_alloc_shash(MD5), right? What about other places
> where it may also do it in kernel? (where ltp just doesn't cover)
> 
> I don't think it makes sense to let SCTP have some code reply on
> FIPS only to make ltp testcase happy, while we can actually fix it
> in ltp by "sysctl".
> 
> Thanks.
> 
Hi Xi,
Thanks for your inputs. I have sent the patches to ltp upstream to handle the fix from ltp codebase.

Regards,
Ashwin Kamat
>>> 
>>> Signed-off-by: Ashwin Dayanand Kamat <kashwindayan@xxxxxxxxxx>
>>> ---
>>> v3:
>>> * Resolved hunk failures.
>>> * Changed the ratelimited notice to be more meaningful.
>>> * Used ternary condition for if/else condtion.
>>> v2:
>>> * The listener can still fail if fips mode is enabled after
>>>  that the netns is initialized.
>>> * Fixed this in sctp_listen_start() as suggested by
>>>  Paolo Abeni <pabeni@xxxxxxxxxx>
>> 
>> FWIIW, this seems reasonable to me.
>> 
>> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
> 
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