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

Stefan Berger
2018-05-30T13:08:56Z

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@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@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
>