Re: [RFC PATCH v2 9/9] Smack: Brutalist io_uring support with debug

Casey Schaufler
2021-08-31T15:03:20Z

On 8/31/2021 7:44 AM, Paul Moore wrote:
> On Wed, Aug 11, 2021 at 4:49 PM Paul Moore <paul@paul-moore.com> wrote:
>> From: Casey Schaufler <casey@schaufler-ca.com>
>>
>> Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE
>> for the override_creds case and CAP_MAC_ADMIN for creating a
>> polling thread. These choices are based on conjecture regarding
>> the intent of the surrounding code.
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> [PM: make the smack_uring_* funcs static]
>> Signed-off-by: Paul Moore <paul@paul-moore.com>
>>
>> ---
>> v2:
>> - made the smack_uring_* funcs static
>> v1:
>> - initial draft
>> ---
>> security/smack/smack_lsm.c | 64 ++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 64 insertions(+)
>>
>> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
>> index 223a6da0e6dc..7fb094098f38 100644
>> --- a/security/smack/smack_lsm.c
>> +++ b/security/smack/smack_lsm.c
>> @@ -4691,6 +4691,66 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
>> return 0;
>> }
>>
>> +#ifdef CONFIG_IO_URING
>> +/**
>> + * smack_uring_override_creds - Is io_uring cred override allowed?
>> + * @new: the target creds
>> + *
>> + * Check to see if the current task is allowed to override it's credentials
>> + * to service an io_uring operation.
>> + */
>> +static int smack_uring_override_creds(const struct cred *new)
>> +{
>> + struct task_smack *tsp = smack_cred(current_cred());
>> + struct task_smack *nsp = smack_cred(new);
>> +
>> +#if 1
>> + if (tsp->smk_task == nsp->smk_task)
>> + pr_info("%s: Smack matches %s\n", __func__,
>> + tsp->smk_task->smk_known);
>> + else
>> + pr_info("%s: Smack override check %s to %s\n", __func__,
>> + tsp->smk_task->smk_known, nsp->smk_task->smk_known);
>> +#endif
> Casey, with the idea of posting a v3 towards the end of the merge
> window next week, without the RFC tag and with the intention of
> merging it into -next during the first/second week of the -rcX phase,
> do you have any objections to me removing the debug code (#if 1 ...
> #endif) from your patch? Did you have any other changes?

I have no other changes. And yes, the debug code should be stripped.
Thank you.

>
>
> --
> paul moore
> www.paul-moore.com