On 01/19/2017 12:43 PM, Robin Murphy wrote:
Hi Laura,
On 19/01/17 01:29, Laura Abbott wrote:
Despite the word 'debug' in CONFIG_DEBUG_SET_MODULE_RONX, this kernel
option provides key security features that are to be expected on a
modern system. Change the name to CONFIG_HARDENED_MODULE_MAPPINGS which
more accurately describes what this option is intended to do.
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
[...]
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 09aff28..ef852e4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -8,6 +8,7 @@ config ARM
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_HARDENED_MAPPINGS if MMU && !XIP_KERNEL
+ select ARCH_HAS_HARDENED_MODULE_MAPPINGS if MMU
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_USE_BUILTIN_BSWAP
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index d83f7c3..426d271 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -1738,17 +1738,6 @@ config PID_IN_CONTEXTIDR
additional instructions during context switch. Say Y here only if you
are planning to use hardware trace tools with this kernel.
-config DEBUG_SET_MODULE_RONX
- bool "Set loadable kernel module data as NX and text as RO"
- depends on MODULES && MMU
- ---help---
- This option helps catch unintended modifications to loadable
- kernel module's text and read-only data. It also prevents execution
- of module data. Such protection may interfere with run-time code
- patching and dynamic kernel tracing - and they might also protect
- against certain classes of kernel exploits.
- If in doubt, say "N".
-
source "drivers/hwtracing/coresight/Kconfig"
endmenu
[...]
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -12,6 +12,7 @@ config ARM64
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_HARDENED_MAPPINGS
+ select ARCH_HAS_HARDENED_MODULE_MAPPINGS
select ARCH_HAS_KCOV
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index a26d27f..1eebe1f 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -71,17 +71,6 @@ config DEBUG_WX
If in doubt, say "Y".
-config DEBUG_SET_MODULE_RONX
- bool "Set loadable kernel module data as NX and text as RO"
- depends on MODULES
- default y
- help
- Is this is set, kernel module text and rodata will be made read-only.
- This is to help catch accidental or malicious attempts to change the
- kernel's executable code.
-
- If in doubt, say Y.
-
config DEBUG_ALIGN_RODATA
depends on ARCH_HAS_HARDENED_MAPPINGS
bool "Align linker sections up to SECTION_SIZE"
[...]
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -69,6 +69,7 @@ config S390
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_HARDENED_MAPPINGS
+ select ARCH_HAS_HARDENED_MODULE_MAPPINGS
select ARCH_HAS_KCOV
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_UBSAN_SANITIZE_ALL
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug
index 26c5d5be..57f8ea9 100644
--- a/arch/s390/Kconfig.debug
+++ b/arch/s390/Kconfig.debug
@@ -17,7 +17,4 @@ config S390_PTDUMP
kernel.
If in doubt, say "N"
-config DEBUG_SET_MODULE_RONX
- def_bool y
- depends on MODULES
endmenu
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9d80cd8..38ce850 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -51,6 +51,7 @@ config X86
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_HARDENED_MAPPINGS
+ select ARCH_HAS_HARDENED_MODULE_MAPPINGS
select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_MMIO_FLUSH
select ARCH_HAS_PMEM_API if X86_64
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 67eec55..69cdd0b 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -109,17 +109,6 @@ config DEBUG_WX
If in doubt, say "Y".
-config DEBUG_SET_MODULE_RONX
- bool "Set loadable kernel module data as NX and text as RO"
- depends on MODULES
- ---help---
- This option helps catch unintended modifications to loadable
- kernel module's text and read-only data. It also prevents execution
- of module data. Such protection may interfere with run-time code
- patching and dynamic kernel tracing - and they might also protect
- against certain classes of kernel exploits.
- If in doubt, say "N".
-
config DEBUG_NX_TEST
tristate "Testcase for the NX non-executable stack feature"
depends on DEBUG_KERNEL && m
[...]
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -174,6 +174,22 @@ config HARDENED_PAGE_MAPPINGS
Unless your system has known restrictions or performance issues, it
is recommended to say Y here.
+config ARCH_HAS_HARDENED_MODULE_MAPPINGS
+ def_bool n
+
+config HARDENED_MODULE_MAPPINGS
+ bool "Mark module mappings with stricter permissions (RO/W^X)"
+ default y
+ depends on ARCH_HAS_HARDENED_MODULE_MAPPINGS
It would seem that this ends up losing the previous dependency on
MODULES - is that intentional?
Robin.
(Apologies, my SMTP was set up incorrectly so this didn't actually
get sent out when I thought it did)
No, good catch. I missed re-adding that when doing the refactoring.
Thanks,
Laura
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