[PATCH 8/8] ima: Differentiate auditing policy rules from "audit" actions

[Paul Moore]

On Wed, May 30, 2018 at 9:08 AM, Stefan Berger
<stefanb at linux.vnet.ibm.com> wrote:
> On 05/30/2018 08:49 AM, Richard Guy Briggs wrote:
>>
>> On 2018-05-24 16:11, Stefan Berger wrote:
>>>
>>> The AUDIT_INTEGRITY_RULE is used for auditing IMA policy rules and
>>> the IMA "audit" policy action.  This patch defines
>>> AUDIT_INTEGRITY_POLICY_RULE to reflect the IMA policy rules.
>>>
>>> With this change we now call integrity_audit_msg_common() to get
>>> common integrity auditing fields. This now produces the following
>>> record when parsing an IMA policy rule:
>>>
>>> type=UNKNOWN[1806] msg=audit(1527004216.690:311): action=dont_measure \
>>>    fsmagic=0x9fa0 pid=1613 uid=0 auid=0 ses=2 \
>>>    subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 \
>>>    op=policy_update cause=parse_rule comm="echo" exe="/usr/bin/echo" \
>>>    tty=tty2 res=1
>>>
>>> Signed-off-by: Stefan Berger <stefanb at linux.vnet.ibm.com>
>>> ---
>>>   include/uapi/linux/audit.h          | 3 ++-
>>>   security/integrity/ima/ima_policy.c | 5 +++--
>>>   2 files changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
>>> index 4e61a9e05132..776e0abd35cf 100644
>>> --- a/include/uapi/linux/audit.h
>>> +++ b/include/uapi/linux/audit.h
>>> @@ -146,7 +146,8 @@
>>>   #define AUDIT_INTEGRITY_STATUS            1802 /* Integrity enable
>>> status */
>>>   #define AUDIT_INTEGRITY_HASH      1803 /* Integrity HASH type */
>>>   #define AUDIT_INTEGRITY_PCR       1804 /* PCR invalidation msgs */
>>> -#define AUDIT_INTEGRITY_RULE       1805 /* policy rule */
>>> +#define AUDIT_INTEGRITY_RULE       1805 /* IMA "audit" action policy
>>> msgs  */
>>> +#define AUDIT_INTEGRITY_POLICY_RULE 1806 /* IMA policy rules */
>>>     #define AUDIT_KERNEL                2000    /* Asynchronous audit
>>> record. NOT A REQUEST. */
>>>   diff --git a/security/integrity/ima/ima_policy.c
>>> b/security/integrity/ima/ima_policy.c
>>> index 3aed25a7178a..a8ae47a386b4 100644
>>> --- a/security/integrity/ima/ima_policy.c
>>> +++ b/security/integrity/ima/ima_policy.c
>>> @@ -634,7 +634,7 @@ static int ima_parse_rule(char *rule, struct
>>> ima_rule_entry *entry)
>>>         int result = 0;
>>>         ab = integrity_audit_log_start(NULL, GFP_KERNEL,
>>> -                                      AUDIT_INTEGRITY_RULE);
>>> +                                      AUDIT_INTEGRITY_POLICY_RULE);
>>
>> Is it possible to connect this record to a syscall by replacing the
>> first parameter (NULL) by current->context?

We're likely going to need to "associate" this record (audit speak for
making the first parameter non-NULL) with others for the audit
container ID work.  If you do it now, Richard's patches will likely
get a few lines smaller and that will surely make him a bit happier :)

> We would have to fix current->context in this case since it is NULL. We get
> to this location by root cat'ing a policy or writing a policy filename into
> /sys/kernel/security/ima/policy.

Perhaps I'm missing something, but current in this case should point
to the process which is writing to the policy file, yes?

-- 
paul moore
www.paul-moore.com