From 69393cb03ccdf29f3b452d3482ef918469d1c098 Mon Sep 17 00:00:00 2001 From: "Christopher M. Riedl" Date: Sat, 7 Sep 2019 01:11:24 -0500 Subject: powerpc/xmon: Restrict when kernel is locked down Xmon should be either fully or partially disabled depending on the kernel lockdown state. Put xmon into read-only mode for lockdown=integrity and prevent user entry into xmon when lockdown=confidentiality. Xmon checks the lockdown state on every attempted entry: (1) during early xmon'ing (2) when triggered via sysrq (3) when toggled via debugfs (4) when triggered via a previously enabled breakpoint The following lockdown state transitions are handled: (1) lockdown=none -> lockdown=integrity set xmon read-only mode (2) lockdown=none -> lockdown=confidentiality clear all breakpoints, set xmon read-only mode, prevent user re-entry into xmon (3) lockdown=integrity -> lockdown=confidentiality clear all breakpoints, set xmon read-only mode, prevent user re-entry into xmon Suggested-by: Andrew Donnellan Signed-off-by: Christopher M. Riedl Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190907061124.1947-3-cmr@informatik.wtf --- include/linux/security.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/security.h b/include/linux/security.h index a8d59d612d27..79567eacb834 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -116,12 +116,14 @@ enum lockdown_reason { LOCKDOWN_MODULE_PARAMETERS, LOCKDOWN_MMIOTRACE, LOCKDOWN_DEBUGFS, + LOCKDOWN_XMON_WR, LOCKDOWN_INTEGRITY_MAX, LOCKDOWN_KCORE, LOCKDOWN_KPROBES, LOCKDOWN_BPF_READ, LOCKDOWN_PERF, LOCKDOWN_TRACEFS, + LOCKDOWN_XMON_RW, LOCKDOWN_CONFIDENTIALITY_MAX, }; -- cgit v1.2.3-59-g8ed1b