[PATCH 3/5] audit: allow interfield comparison between gid and ogid

[Eric Paris]

Allow audit rules to compare the gid of the running task to the gid of the
inode in question.

Signed-off-by: Eric Paris <eparis at redhat.com>
---
 include/linux/audit.h |    3 ++-
 kernel/auditsc.c      |    6 ++++++
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 7bf31e2..4649506 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -184,8 +184,9 @@
 
 /* AUDIT_FIELD_COMPARE rule list */
 #define AUDIT_COMPARE_UID_TO_OBJ_UID	1
+#define AUDIT_COMPARE_GID_TO_OBJ_GID	2
 
-#define AUDIT_MAX_FIELD_COMPARE	AUDIT_COMPARE_UID_TO_OBJ_UID
+#define AUDIT_MAX_FIELD_COMPARE	AUDIT_COMPARE_GID_TO_OBJ_GID
 /* Rule fields */
 				/* These are useful when checking the
 				 * task structure at task creation time
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 45c13c5..cc1197f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -474,6 +474,8 @@ static int audit_compare_id(uid_t uid1,
 	uid_t uid2;
 	int rc;
 
+	BUILD_BUG_ON(sizeof(uid_t) != sizeof(gid_t));
+
 	if (name) {
 		addr = (unsigned long)name;
 		addr += name_offset;
@@ -510,6 +512,10 @@ static int audit_field_compare(struct task_struct *tsk,
 		return audit_compare_id(cred->uid,
 					name, offsetof(struct audit_names, uid),
 					f, ctx);
+	case AUDIT_COMPARE_GID_TO_OBJ_GID:
+		return audit_compare_id(cred->gid,
+					name, offsetof(struct audit_names, gid),
+					f, ctx);
 	default:
 		WARN(1, "Missing AUDIT_COMPARE define.  Report as a bug\n");
 		return 0;
-- 
1.7.1