audit: comparison on interprocess fields

This allows audit to specify rules in which we compare two fields of a
process.  Such as is the running process uid != to the running process
euid?

Signed-off-by: Peter Moody <pmoody@google.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b8cee46..593237e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -545,6 +545,45 @@
 		return audit_compare_id(cred->fsgid,
 					name, offsetof(struct audit_names, gid),
 					f, ctx);
+	/* uid comparisons */
+	case AUDIT_COMPARE_UID_TO_AUID:
+		return audit_comparator(cred->uid, f->op, tsk->loginuid);
+	case AUDIT_COMPARE_UID_TO_EUID:
+		return audit_comparator(cred->uid, f->op, cred->euid);
+	case AUDIT_COMPARE_UID_TO_SUID:
+		return audit_comparator(cred->uid, f->op, cred->suid);
+	case AUDIT_COMPARE_UID_TO_FSUID:
+		return audit_comparator(cred->uid, f->op, cred->fsuid);
+	/* auid comparisons */
+	case AUDIT_COMPARE_AUID_TO_EUID:
+		return audit_comparator(tsk->loginuid, f->op, cred->euid);
+	case AUDIT_COMPARE_AUID_TO_SUID:
+		return audit_comparator(tsk->loginuid, f->op, cred->suid);
+	case AUDIT_COMPARE_AUID_TO_FSUID:
+		return audit_comparator(tsk->loginuid, f->op, cred->fsuid);
+	/* euid comparisons */
+	case AUDIT_COMPARE_EUID_TO_SUID:
+		return audit_comparator(cred->euid, f->op, cred->suid);
+	case AUDIT_COMPARE_EUID_TO_FSUID:
+		return audit_comparator(cred->euid, f->op, cred->fsuid);
+	/* suid comparisons */
+	case AUDIT_COMPARE_SUID_TO_FSUID:
+		return audit_comparator(cred->suid, f->op, cred->fsuid);
+	/* gid comparisons */
+	case AUDIT_COMPARE_GID_TO_EGID:
+		return audit_comparator(cred->gid, f->op, cred->egid);
+	case AUDIT_COMPARE_GID_TO_SGID:
+		return audit_comparator(cred->gid, f->op, cred->sgid);
+	case AUDIT_COMPARE_GID_TO_FSGID:
+		return audit_comparator(cred->gid, f->op, cred->fsgid);
+	/* egid comparisons */
+	case AUDIT_COMPARE_EGID_TO_SGID:
+		return audit_comparator(cred->egid, f->op, cred->sgid);
+	case AUDIT_COMPARE_EGID_TO_FSGID:
+		return audit_comparator(cred->egid, f->op, cred->fsgid);
+	/* sgid comparison */
+	case AUDIT_COMPARE_SGID_TO_FSGID:
+		return audit_comparator(cred->sgid, f->op, cred->fsgid);
 	default:
 		WARN(1, "Missing AUDIT_COMPARE define.  Report as a bug\n");
 		return 0;