diff options
Diffstat (limited to 'security/Kconfig.hardening')
| -rw-r--r-- | security/Kconfig.hardening | 101 |
1 files changed, 97 insertions, 4 deletions
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index d051f8ceefdd..d766b7d0ffd1 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -22,11 +22,17 @@ menu "Memory initialization" config CC_HAS_AUTO_VAR_INIT_PATTERN def_bool $(cc-option,-ftrivial-auto-var-init=pattern) -config CC_HAS_AUTO_VAR_INIT_ZERO - # GCC ignores the -enable flag, so we can test for the feature with - # a single invocation using the flag, but drop it as appropriate in - # the Makefile, depending on the presence of Clang. +config CC_HAS_AUTO_VAR_INIT_ZERO_BARE + def_bool $(cc-option,-ftrivial-auto-var-init=zero) + +config CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER + # Clang 16 and later warn about using the -enable flag, but it + # is required before then. def_bool $(cc-option,-ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang) + depends on !CC_HAS_AUTO_VAR_INIT_ZERO_BARE + +config CC_HAS_AUTO_VAR_INIT_ZERO + def_bool CC_HAS_AUTO_VAR_INIT_ZERO_BARE || CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER choice prompt "Initialize kernel stack variables at function entry" @@ -106,6 +112,7 @@ choice config INIT_STACK_ALL_PATTERN bool "pattern-init everything (strongest)" depends on CC_HAS_AUTO_VAR_INIT_PATTERN + depends on !KMSAN help Initializes everything on the stack (including padding) with a specific debug value. This is intended to eliminate @@ -124,6 +131,7 @@ choice config INIT_STACK_ALL_ZERO bool "zero-init everything (strongest and safest)" depends on CC_HAS_AUTO_VAR_INIT_ZERO + depends on !KMSAN help Initializes everything on the stack (including padding) with a zero value. This is intended to eliminate all @@ -174,6 +182,16 @@ config GCC_PLUGIN_STACKLEAK * https://grsecurity.net/ * https://pax.grsecurity.net/ +config GCC_PLUGIN_STACKLEAK_VERBOSE + bool "Report stack depth analysis instrumentation" if EXPERT + depends on GCC_PLUGIN_STACKLEAK + depends on !COMPILE_TEST # too noisy + help + This option will cause a warning to be printed each time the + stackleak plugin finds a function it thinks needs to be + instrumented. This is useful for comparing coverage between + builds. + config STACKLEAK_TRACK_MIN_SIZE int "Minimum stack frame size of functions tracked by STACKLEAK" default 100 @@ -208,6 +226,7 @@ config STACKLEAK_RUNTIME_DISABLE config INIT_ON_ALLOC_DEFAULT_ON bool "Enable heap memory zeroing on allocation by default" + depends on !KMSAN help This has the effect of setting "init_on_alloc=1" on the kernel command line. This can be disabled with "init_on_alloc=0". @@ -220,6 +239,7 @@ config INIT_ON_ALLOC_DEFAULT_ON config INIT_ON_FREE_DEFAULT_ON bool "Enable heap memory zeroing on free by default" + depends on !KMSAN help This has the effect of setting "init_on_free=1" on the kernel command line. This can be disabled with "init_on_free=0". @@ -256,4 +276,77 @@ config ZERO_CALL_USED_REGS endmenu +config CC_HAS_RANDSTRUCT + def_bool $(cc-option,-frandomize-layout-seed-file=/dev/null) + +choice + prompt "Randomize layout of sensitive kernel structures" + default RANDSTRUCT_FULL if COMPILE_TEST && (GCC_PLUGINS || CC_HAS_RANDSTRUCT) + default RANDSTRUCT_NONE + help + If you enable this, the layouts of structures that are entirely + function pointers (and have not been manually annotated with + __no_randomize_layout), or structures that have been explicitly + marked with __randomize_layout, will be randomized at compile-time. + This can introduce the requirement of an additional information + exposure vulnerability for exploits targeting these structure + types. + + Enabling this feature will introduce some performance impact, + slightly increase memory usage, and prevent the use of forensic + tools like Volatility against the system (unless the kernel + source tree isn't cleaned after kernel installation). + + The seed used for compilation is in scripts/basic/randomize.seed. + It remains after a "make clean" to allow for external modules to + be compiled with the existing seed and will be removed by a + "make mrproper" or "make distclean". This file should not be made + public, or the structure layout can be determined. + + config RANDSTRUCT_NONE + bool "Disable structure layout randomization" + help + Build normally: no structure layout randomization. + + config RANDSTRUCT_FULL + bool "Fully randomize structure layout" + depends on CC_HAS_RANDSTRUCT || GCC_PLUGINS + select MODVERSIONS if MODULES + help + Fully randomize the member layout of sensitive + structures as much as possible, which may have both a + memory size and performance impact. + + One difference between the Clang and GCC plugin + implementations is the handling of bitfields. The GCC + plugin treats them as fully separate variables, + introducing sometimes significant padding. Clang tries + to keep adjacent bitfields together, but with their bit + ordering randomized. + + config RANDSTRUCT_PERFORMANCE + bool "Limit randomization of structure layout to cache-lines" + depends on GCC_PLUGINS + select MODVERSIONS if MODULES + help + Randomization of sensitive kernel structures will make a + best effort at restricting randomization to cacheline-sized + groups of members. It will further not randomize bitfields + in structures. This reduces the performance hit of RANDSTRUCT + at the cost of weakened randomization. +endchoice + +config RANDSTRUCT + def_bool !RANDSTRUCT_NONE + +config GCC_PLUGIN_RANDSTRUCT + def_bool GCC_PLUGINS && RANDSTRUCT + help + Use GCC plugin to randomize structure layout. + + This plugin was ported from grsecurity/PaX. More + information at: + * https://grsecurity.net/ + * https://pax.grsecurity.net/ + endmenu |