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Date: Thu, 17 Dec 2015 09:57:49 -0500
From: David Windsor <dave@...gbits.org>
To: kernel-hardening@...ts.openwall.com
Cc: David Windsor <dave@...gbits.org>
Subject: [RFC PATCH v2 11/12] security: add Kconfig options for PAX_REFCOUNT
Currently the Kconfig options for this feature retain the original
naming from Pax/grsecurity.
Signed-off-by: David Windsor <dave@...gbits.org>
---
security/Kconfig | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/security/Kconfig b/security/Kconfig
index bf4ec46..cf08034 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -4,6 +4,78 @@
menu "Security options"
+menu "Grsecurity"
+
+config GRKERNSEC
+ bool "Grsecurity"
+ help
+ If you say Y here, you will be able to configure many features
+ that will enhance the security of your system. It is highly
+ recommended that you say Y here and read through the help
+ for each option so that you fully understand the features and
+ can evaluate their usefulness for your machine.
+
+choice
+ prompt "Configuration Method"
+ depends on GRKERNSEC
+ default GRKERNSEC_CONFIG_CUSTOM
+ help
+
+config GRKERNSEC_CONFIG_AUTO
+ bool "Automatic"
+ help
+ If you choose this configuration method, you'll be able to answer a small
+ number of simple questions about how you plan to use this kernel.
+ The settings of grsecurity and PaX will be automatically configured for
+ the highest commonly-used settings within the provided constraints.
+
+ If you require additional configuration, custom changes can still be made
+ from the "custom configuration" menu.
+
+config GRKERNSEC_CONFIG_CUSTOM
+ bool "Custom"
+ help
+ If you choose this configuration method, you'll be able to configure all
+ grsecurity and PaX settings manually. Via this method, no options are
+ automatically enabled.
+
+ Take note that if menuconfig is exited with this configuration method
+ chosen, you will not be able to use the automatic configuration methods
+ without starting again with a kernel configuration with no grsecurity
+ or PaX options specified inside.
+
+endchoice
+
+menu "PaX"
+
+menu "Miscellaneous hardening features"
+
+config PAX_REFCOUNT
+ bool "Prevent various kernel object reference counter overflows"
+ default y if GRKERNSEC_CONFIG_AUTO
+ depends on GRKERNSEC && ((ARM && (CPU_V6 || CPU_V6K || CPU_V7)) || MIPS || PPC || SPARC64 || X86)
+ help
+ By saying Y here the kernel will detect and prevent overflowing
+ various (but not all) kinds of object reference counters. Such
+ overflows can normally occur due to bugs only and are often, if
+ not always, exploitable.
+
+ The tradeoff is that data structures protected by an overflowed
+ refcount will never be freed and therefore will leak memory. Note
+ that this leak also happens even without this protection but in
+ that case the overflow can eventually trigger the freeing of the
+ data structure while it is still being used elsewhere, resulting
+ in the exploitable situation that this feature prevents.
+
+ Since this has a negligible performance impact, you should enable
+ this feature.
+
+endmenu
+
+endmenu
+
+endmenu
+
source security/keys/Kconfig
config SECURITY_DMESG_RESTRICT
--
2.5.0
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