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

[Stefan Berger]

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 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.




>
>>   	entry->uid = INVALID_UID;
>>   	entry->fowner = INVALID_UID;
>> @@ -926,7 +926,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
>>   		temp_ima_appraise |= IMA_APPRAISE_FIRMWARE;
>>   	else if (entry->func == POLICY_CHECK)
>>   		temp_ima_appraise |= IMA_APPRAISE_POLICY;
>> -	audit_log_format(ab, "res=%d", !result);
>> +	integrity_audit_msg_common(ab, NULL, NULL,
>> +				   "policy_update", "parse_rule", result);
>>   	audit_log_end(ab);
>>   	return result;
>>   }
> - RGB
>
> --
> Richard Guy Briggs <rgb at redhat.com>
> Sr. S/W Engineer, Kernel Security, Base Operating Systems
> Remote, Ottawa, Red Hat Canada
> IRC: rgb, SunRaycer
> Voice: +1.647.777.2635, Internal: (81) 32635
>