linux-6.12.1/security/Kconfig.hardening

1 # SPDX-License-Identifier: GPL-2.0-only
12 	  flaws, this plugin is available to identify and zero-initialize
23 	def_bool $(cc-option,-ftrivial-auto-var-init=pattern)
26 	def_bool $(cc-option,-ftrivial-auto-var-init=zero)
29 	# Clang 16 and later warn about using the -enable flag, but it
31 …def_bool $(cc-option,-ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-wi…
47 	  variables initialized), but the performance impact depends
64 		bool "zero-init structs marked for userspace (weak)"
69 		  Zero-initialize any structures on the stack containing
72 		  exposures, like CVE-2013-2141:
76 		bool "zero-init structs passed by reference (strong)"
82 		  Zero-initialize any structures on the stack that may
86 		  exposures, like CVE-2017-1000410:
89 		  As a side-effect, this keeps a lot of variables on the
95 		bool "zero-init everything passed by reference (very strong)"
101 		  Zero-initialize any stack variables that may be passed
107 		  As a side-effect, this keeps a lot of variables on the
113 		bool "pattern-init everything (strongest)"
125 		  non-NULL values, buffer sizes and indices are very big. The
126 		  pattern is situation-specific; Clang on 64-bit uses 0xAA
128 		  which use 0xFF repeating (-NaN). Clang on 32-bit uses 0xFF
132 		bool "zero-init everything (strongest and safest)"
143 		  (immediately NUL-terminated), pointers (NULL), indices
172 	  most uninitialized stack variable attacks, with the performance
176 	  The performance impact on a single CPU system kernel compilation
216 	  can be useful for estimating the STACKLEAK performance impact for
236 	  heap content exposures. The performance impact varies by
238 	  workloads have measured as high as 7%.
253 	  The performance impact varies by workload, but is more expensive
255 	  touching "cold" memory areas. Most cases see 3-5% impact. Some
256 	  synthetic workloads have measured as high as 8%.
259 	def_bool $(cc-option,-fzero-call-used-regs=used-gpr)
261 	# https://github.com/llvm/llvm-project/issues/59242
268 	  At the end of functions, always zero any caller-used register
274 	  generated "write-what-where" gadgets) in the resulting kernel
275 	  image. This has a less than 1% performance impact on most
287 	  Minimal integrity checking in the linked-list manipulation routines
306 	def_bool $(cc-option,-frandomize-layout-seed-file=/dev/null)
308 	# Clang 16 due to https://github.com/llvm/llvm-project/issues/60349
319 	  marked with __randomize_layout, will be randomized at compile-time.
324 	  Enabling this feature will introduce some performance impact,
347 		  memory size and performance impact.
357 		bool "Limit randomization of structure layout to cache-lines"
362 		  best effort at restricting randomization to cacheline-sized
364 		  in structures. This reduces the performance hit of RANDSTRUCT