syslog: distinguish between /proc/kmsg and syscalls
This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls. By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor. For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged
behavior.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/include/linux/syslog.h b/include/linux/syslog.h
new file mode 100644
index 0000000..5f02b18
--- /dev/null
+++ b/include/linux/syslog.h
@@ -0,0 +1,29 @@
+/* Syslog internals
+ *
+ * Copyright 2010 Canonical, Ltd.
+ * Author: Kees Cook <kees.cook@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _LINUX_SYSLOG_H
+#define _LINUX_SYSLOG_H
+
+#define SYSLOG_FROM_CALL 0
+#define SYSLOG_FROM_FILE 1
+
+int do_syslog(int type, char __user *buf, int count, bool from_file);
+
+#endif /* _LINUX_SYSLOG_H */