Thread (10 messages) 10 messages, 3 authors, 2018-06-06

Re: [PATCH v3 3/4] ima: Do not audit if CONFIG_INTEGRITY_AUDIT is not set

From: Paul Moore <paul@paul-moore.com>
Date: 2018-06-05 00:16:46
Also in: lkml

On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
If Integrity is not auditing, IMA shouldn't audit, either.

Signed-off-by: Stefan Berger <redacted>
---
 security/integrity/ima/Kconfig      |  1 +
 security/integrity/ima/ima_policy.c |  6 +++++-
 security/integrity/integrity.h      | 15 +++++++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 6a8f67714c83..94c2151331aa 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -12,6 +12,7 @@ config IMA
        select TCG_TIS if TCG_TPM && X86
        select TCG_CRB if TCG_TPM && ACPI
        select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
+       select INTEGRITY_AUDIT if AUDIT
        help
          The Trusted Computing Group(TCG) runtime Integrity
          Measurement Architecture(IMA) maintains a list of hash
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3fcf0935468c..bc99713dfe57 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -628,6 +628,9 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
                              bool (*rule_operator)(kuid_t, kuid_t))
 {
+       if (!ab)
+               return;
+
        if (rule_operator == &uid_gt)
                audit_log_format(ab, "%s>", key);
        else if (rule_operator == &uid_lt)
@@ -649,7 +652,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
        bool uid_token;
        int result = 0;

-       ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
+       ab = integrity_audit_log_start(NULL, GFP_KERNEL,
+                                      AUDIT_INTEGRITY_RULE);
There was a lot of confusion here, so this is understandable, but you
should pass "audit_context()"[1] as the first parameter instead of
NULL.  Other than that this patch looks fine.

[1] In Linus' tree at the moment you would need to use
current->audit_context, but the audit PR heading to Linus during this
merge window will introduce the "audit_context()" function which is
preferable as we may need to change things around a bit in the near
future.
quoted hunk ↗ jump to hunk
        entry->uid = INVALID_UID;
        entry->fowner = INVALID_UID;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0bb372eed62a..e60473b13a8d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -15,6 +15,7 @@
 #include <linux/integrity.h>
 #include <crypto/sha.h>
 #include <linux/key.h>
+#include <linux/audit.h>

 /* iint action cache flags */
 #define IMA_MEASURE            0x00000001
@@ -199,6 +200,13 @@ static inline void evm_load_x509(void)
 void integrity_audit_msg(int audit_msgno, struct inode *inode,
                         const unsigned char *fname, const char *op,
                         const char *cause, int result, int info);
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+       return audit_log_start(ctx, gfp_mask, type);
+}
+
 #else
 static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
                                       const unsigned char *fname,
@@ -206,4 +214,11 @@ static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
                                       int result, int info)
 {
 }
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+       return NULL;
+}
+
 #endif
--
2.13.6
-- 
paul moore
www.paul-moore.com
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