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-rw-r--r--mm/Kconfig.debug32
1 files changed, 32 insertions, 0 deletions
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 0271b22e063f..2409f7fc1567 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -118,6 +118,38 @@ config DEBUG_RODATA_TEST
---help---
This option enables a testcase for the setting rodata read-only.
+config ARCH_HAS_DEBUG_WX
+ bool
+
+config DEBUG_WX
+ bool "Warn on W+X mappings at boot"
+ depends on ARCH_HAS_DEBUG_WX
+ depends on MMU
+ select PTDUMP_CORE
+ help
+ Generate a warning if any W+X mappings are found at boot.
+
+ This is useful for discovering cases where the kernel is leaving W+X
+ mappings after applying NX, as such mappings are a security risk.
+
+ Look for a message in dmesg output like this:
+
+ <arch>/mm: Checked W+X mappings: passed, no W+X pages found.
+
+ or like this, if the check failed:
+
+ <arch>/mm: Checked W+X mappings: failed, <N> W+X pages found.
+
+ Note that even if the check fails, your kernel is possibly
+ still fine, as W+X mappings are not a security hole in
+ themselves, what they do is that they make the exploitation
+ of other unfixed kernel bugs easier.
+
+ There is no runtime or memory usage effect of this option
+ once the kernel has booted up - it's a one time check.
+
+ If in doubt, say "Y".
+
config GENERIC_PTDUMP
bool