Re: [PATCH 04/58] LSM: Create an lsm_export data structure.

On 6/1/2019 8:23 AM, Kees Cook wrote:

On Fri, May 31, 2019 at 04:09:26PM -0700, Casey Schaufler wrote:

quoted

When more than one security module is exporting data to
audit and networking sub-systems a single 32 bit integer
is no longer sufficient to represent the data. Add a
structure to be used instead.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Reviewed-by: Kees Cook <redacted>

Thoughts below...

quoted

---
 include/linux/security.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/security.h b/include/linux/security.h
index 49f2685324b0..81f9f79f9a1e 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h

@@ -76,6 +76,18 @@ enum lsm_event {
 	LSM_POLICY_CHANGE,
 };
 
+/* Data exported by the security modules */
+struct lsm_export {
+	u32	selinux;
+	u32	smack;
+	u32	apparmor;
+	u32	flags;
+};

I think it might make more logical sent to leave flags at the start.
While I don't expect to add more fields, I find it surprising that
it is at the end. :)

Data structure randomization notwithstanding, it
doesn't matter to me, so I'll put the flags first.
This came about because I initially didn't think I'd
need flags, and they were add to the end when I determined
I did.

-Kees

quoted

+#define LSM_EXPORT_NONE		0x00
+#define LSM_EXPORT_SELINUX	0x01
+#define LSM_EXPORT_SMACK	0x02
+#define LSM_EXPORT_APPARMOR	0x04
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, unsigned int opts);
-- 
2.19.1