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

From: Stefan Berger
Date: Wed May 30 2018 - 09:08:59 EST


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@xxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx>
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