diff options
Diffstat (limited to 'security/Kconfig.hardening')
| -rw-r--r-- | security/Kconfig.hardening | 114 |
1 files changed, 36 insertions, 78 deletions
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 2cff851ebfd7..fd1238753cad 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -1,22 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only menu "Kernel hardening options" -config GCC_PLUGIN_STRUCTLEAK - bool - help - While the kernel is built with warnings enabled for any missed - stack variable initializations, this warning is silenced for - anything passed by reference to another function, under the - occasionally misguided assumption that the function will do - the initialization. As this regularly leads to exploitable - flaws, this plugin is available to identify and zero-initialize - such variables, depending on the chosen level of coverage. - - This plugin was originally ported from grsecurity/PaX. More - information at: - * https://grsecurity.net/ - * https://pax.grsecurity.net/ - menu "Memory initialization" config CC_HAS_AUTO_VAR_INIT_PATTERN @@ -36,7 +20,6 @@ config CC_HAS_AUTO_VAR_INIT_ZERO choice prompt "Initialize kernel stack variables at function entry" - default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if COMPILE_TEST && GCC_PLUGINS default INIT_STACK_ALL_PATTERN if COMPILE_TEST && CC_HAS_AUTO_VAR_INIT_PATTERN default INIT_STACK_ALL_ZERO if CC_HAS_AUTO_VAR_INIT_ZERO default INIT_STACK_NONE @@ -60,55 +43,6 @@ choice classes of uninitialized stack variable exploits and information exposures. - config GCC_PLUGIN_STRUCTLEAK_USER - bool "zero-init structs marked for userspace (weak)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any structures on the stack containing - a __user attribute. This can prevent some classes of - uninitialized stack variable exploits and information - exposures, like CVE-2013-2141: - https://git.kernel.org/linus/b9e146d8eb3b9eca - - config GCC_PLUGIN_STRUCTLEAK_BYREF - bool "zero-init structs passed by reference (strong)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - depends on !(KASAN && KASAN_STACK) - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any structures on the stack that may - be passed by reference and had not already been - explicitly initialized. This can prevent most classes - of uninitialized stack variable exploits and information - exposures, like CVE-2017-1000410: - https://git.kernel.org/linus/06e7e776ca4d3654 - - As a side-effect, this keeps a lot of variables on the - stack that can otherwise be optimized out, so combining - this with CONFIG_KASAN_STACK can lead to a stack overflow - and is disallowed. - - config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL - bool "zero-init everything passed by reference (very strong)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - depends on !(KASAN && KASAN_STACK) - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any stack variables that may be passed - by reference and had not already been explicitly - initialized. This is intended to eliminate all classes - of uninitialized stack variable exploits and information - exposures. - - As a side-effect, this keeps a lot of variables on the - stack that can otherwise be optimized out, so combining - this with CONFIG_KASAN_STACK can lead to a stack overflow - and is disallowed. - config INIT_STACK_ALL_PATTERN bool "pattern-init everything (strongest)" depends on CC_HAS_AUTO_VAR_INIT_PATTERN @@ -127,6 +61,7 @@ choice repeating for all types and padding except float and double which use 0xFF repeating (-NaN). Clang on 32-bit uses 0xFF repeating for all types and padding. + GCC uses 0xFE repeating for all types, and zero for padding. config INIT_STACK_ALL_ZERO bool "zero-init everything (strongest and safest)" @@ -147,16 +82,6 @@ choice endchoice -config GCC_PLUGIN_STRUCTLEAK_VERBOSE - bool "Report forcefully initialized variables" - depends on GCC_PLUGIN_STRUCTLEAK - depends on !COMPILE_TEST # too noisy - help - This option will cause a warning to be printed each time the - structleak plugin finds a variable it thinks needs to be - initialized. Since not all existing initializers are detected - by the plugin, this can produce false positive warnings. - config GCC_PLUGIN_STACKLEAK bool "Poison kernel stack before returning from syscalls" depends on GCC_PLUGINS @@ -279,6 +204,39 @@ config ZERO_CALL_USED_REGS endmenu +menu "Bounds checking" + +config FORTIFY_SOURCE + bool "Harden common str/mem functions against buffer overflows" + depends on ARCH_HAS_FORTIFY_SOURCE + # https://github.com/llvm/llvm-project/issues/53645 + depends on !X86_32 || !CC_IS_CLANG || CLANG_VERSION >= 160000 + help + Detect overflows of buffers in common string and memory functions + where the compiler can determine and validate the buffer sizes. + +config HARDENED_USERCOPY + bool "Harden memory copies between kernel and userspace" + imply STRICT_DEVMEM + help + This option checks for obviously wrong memory regions when + copying memory to/from the kernel (via copy_to_user() and + copy_from_user() functions) by rejecting memory ranges that + are larger than the specified heap object, span multiple + separately allocated pages, are not on the process stack, + or are part of the kernel text. This prevents entire classes + of heap overflow exploits and similar kernel memory exposures. + +config HARDENED_USERCOPY_DEFAULT_ON + bool "Harden memory copies by default" + depends on HARDENED_USERCOPY + default HARDENED_USERCOPY + help + This has the effect of setting "hardened_usercopy=on" on the kernel + command line. This can be disabled with "hardened_usercopy=off". + +endmenu + menu "Hardening of kernel data structures" config LIST_HARDENED @@ -340,7 +298,7 @@ choice config RANDSTRUCT_FULL bool "Fully randomize structure layout" depends on CC_HAS_RANDSTRUCT || GCC_PLUGINS - select MODVERSIONS if MODULES + select MODVERSIONS if MODULES && !COMPILE_TEST help Fully randomize the member layout of sensitive structures as much as possible, which may have both a @@ -356,7 +314,7 @@ choice config RANDSTRUCT_PERFORMANCE bool "Limit randomization of structure layout to cache-lines" depends on GCC_PLUGINS - select MODVERSIONS if MODULES + select MODVERSIONS if MODULES && !COMPILE_TEST help Randomization of sensitive kernel structures will make a best effort at restricting randomization to cacheline-sized |