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SubjectRe: [PATCH v2] net/sctp: Make sha1 as default algorithm if fips is enabled
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> On 27-May-2023, at 7:43 PM, Simon Horman <simon.horman@corigine.com> wrote:
>
> !! External Email
>
> On Sat, May 27, 2023 at 07:49:26AM +0000, Ashwin Dayanand Kamat wrote:
>>
>>
>>> On 25-Mar-2023, at 12:03 PM, Ashwin Dayanand Kamat <kashwindayan@vmware.com> wrote:
>>>
>>>
>>>> On 23-Mar-2023, at 2:16 AM, Simon Horman <simon.horman@corigine.com> wrote:
>>>>
>>>> !! External Email
>>>>
>>>> On Wed, Mar 22, 2023 at 07:34:40PM +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.
>>>>>
>>>>> Fixes: ltp testcase failure "cve-2018-5803 sctp_big_chunk"
>>>>> Signed-off-by: Ashwin Dayanand Kamat <kashwindayan@vmware.com>
>>>>> ---
>>>>> v2:
>>>>> the listener can still fail if fips mode is enabled after
>>>>> that the netns is initialized. So taking action in sctp_listen_start()
>>>>> and buming a ratelimited notice the selected hmac is changed due to fips.
>>>>> ---
>>>>> net/sctp/socket.c | 10 ++++++++++
>>>>> 1 file changed, 10 insertions(+)
>>>>>
>>>>> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
>>>>> index b91616f819de..a1107f42869e 100644
>>>>> --- a/net/sctp/socket.c
>>>>> +++ b/net/sctp/socket.c
>>>>> @@ -49,6 +49,7 @@
>>>>> #include <linux/poll.h>
>>>>> #include <linux/init.h>
>>>>> #include <linux/slab.h>
>>>>> +#include <linux/fips.h>
>>>>> #include <linux/file.h>
>>>>> #include <linux/compat.h>
>>>>> #include <linux/rhashtable.h>
>>>>> @@ -8496,6 +8497,15 @@ static int sctp_listen_start(struct sock *sk, int backlog)
>>>>> struct crypto_shash *tfm = NULL;
>>>>> char alg[32];
>>>>>
>>>>> + if (fips_enabled && !strcmp(sp->sctp_hmac_alg, "md5")) {
>>>>> +#if (IS_ENABLED(CONFIG_SCTP_DEFAULT_COOKIE_HMAC_SHA1))
>>>>
>>>> I'm probably misunderstanding things, but would
>>>> IS_ENABLED(CONFIG_SCTP_COOKIE_HMAC_SHA1)
>>>> be more appropriate here?
>>>>
>>>
>>> Hi Simon,
>>> I have moved the same check from sctp_init() to here based on the review for v1 patch.
>>> Please let me know if there is any alternative which can be used?
>>>
>>> Thanks,
>>> Ashwin Kamat
>>>
>> Hi Team,
>> Any update on this?
>
> Hi Ashwin,
>
> I don't recall exactly what I was thinking 2 months ago.
> But looking at this a second time it seems that I may have misread your
> patch: I now have no objections to it in its original form.
Thanks Simon.
I have Updated the v3 patch with some minor changes. Please review the same.

>
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