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192.168.1.100 / T800 / 15d4438f3c457b15d5b7f076bba313638bae4402 / . / src / kernel / linux / v4.19 / lib / Kconfig.kasan
blob: 5aba7639d0c30385fd77f683b2bafe0c814fc9da [file] [log] [blame]
xjb04a4022021-11-25 15:01:52 +0800[diff] [blame]1# This config refers to the generic KASAN mode.
2config HAVE_ARCH_KASAN
3 bool
4
5config HAVE_ARCH_KASAN_SW_TAGS
6 bool
7
8config CC_HAS_KASAN_GENERIC
9 def_bool $(cc-option, -fsanitize=kernel-address)
10
11config CC_HAS_KASAN_SW_TAGS
12 def_bool $(cc-option, -fsanitize=kernel-hwaddress)
13
14config KASAN
15 bool "KASAN: runtime memory debugger"
16 depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
17 (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
18 depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
19 help
20 Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
21 designed to find out-of-bounds accesses and use-after-free bugs.
22 See Documentation/dev-tools/kasan.rst for details.
23
24choice
25 prompt "KASAN mode"
26 depends on KASAN
27 default KASAN_GENERIC
28 help
29 KASAN has two modes: generic KASAN (similar to userspace ASan,
30 x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
31 software tag-based KASAN (a version based on software memory
32 tagging, arm64 only, similar to userspace HWASan, enabled with
33 CONFIG_KASAN_SW_TAGS).
34 Both generic and tag-based KASAN are strictly debugging features.
35
36config KASAN_GENERIC
37 bool "Generic mode"
38 depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
39 depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
40 select SLUB_DEBUG if SLUB
41 select CONSTRUCTORS
42 select STACKDEPOT
43 help
44 Enables generic KASAN mode.
45 Supported in both GCC and Clang. With GCC it requires version 4.9.2
46 or later for basic support and version 5.0 or later for detection of
47 out-of-bounds accesses for stack and global variables and for inline
48 instrumentation mode (CONFIG_KASAN_INLINE). With Clang it requires
49 version 3.7.0 or later and it doesn't support detection of
50 out-of-bounds accesses for global variables yet.
51 This mode consumes about 1/8th of available memory at kernel start
52 and introduces an overhead of ~x1.5 for the rest of the allocations.
53 The performance slowdown is ~x3.
54 For better error detection enable CONFIG_STACKTRACE.
55 Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
56 (the resulting kernel does not boot).
57
58config KASAN_SW_TAGS
59 bool "Software tag-based mode"
60 depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
61 depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
62 select SLUB_DEBUG if SLUB
63 select CONSTRUCTORS
64 select STACKDEPOT
65 help
66 Enables software tag-based KASAN mode.
67 This mode requires Top Byte Ignore support by the CPU and therefore
68 is only supported for arm64.
69 This mode requires Clang version 7.0.0 or later.
70 This mode consumes about 1/16th of available memory at kernel start
71 and introduces an overhead of ~20% for the rest of the allocations.
72 This mode may potentially introduce problems relating to pointer
73 casting and comparison, as it embeds tags into the top byte of each
74 pointer.
75 For better error detection enable CONFIG_STACKTRACE.
76 Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
77 (the resulting kernel does not boot).
78
79endchoice
80
81choice
82 prompt "Instrumentation type"
83 depends on KASAN
84 default KASAN_OUTLINE
85
86config KASAN_OUTLINE
87 bool "Outline instrumentation"
88 help
89 Before every memory access compiler insert function call
90 __asan_load*/__asan_store*. These functions performs check
91 of shadow memory. This is slower than inline instrumentation,
92 however it doesn't bloat size of kernel's .text section so
93 much as inline does.
94
95config KASAN_INLINE
96 bool "Inline instrumentation"
97 help
98 Compiler directly inserts code checking shadow memory before
99 memory accesses. This is faster than outline (in some workloads
100 it gives about x2 boost over outline instrumentation), but
101 make kernel's .text size much bigger.
102 For CONFIG_KASAN_GENERIC this requires GCC 5.0 or later.
103
104endchoice
105
106config KASAN_STACK_ENABLE
107 bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
108 default !(CLANG_VERSION < 90000)
109 depends on KASAN
110 help
111 The LLVM stack address sanitizer has a know problem that
112 causes excessive stack usage in a lot of functions, see
113 https://bugs.llvm.org/show_bug.cgi?id=38809
114 Disabling asan-stack makes it safe to run kernels build
115 with clang-8 with KASAN enabled, though it loses some of
116 the functionality.
117 This feature is always disabled when compile-testing with clang-8
118 or earlier to avoid cluttering the output in stack overflow
119 warnings, but clang-8 users can still enable it for builds without
120 CONFIG_COMPILE_TEST. On gcc and later clang versions it is
121 assumed to always be safe to use and enabled by default.
122
123config KASAN_STACK
124 int
125 default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
126 default 0
127
128config KASAN_SW_TAGS_IDENTIFY
129 bool "Enable memory corruption identification"
130 depends on KASAN_SW_TAGS
131 help
132 This option enables best-effort identification of bug type
133 (use-after-free or out-of-bounds) at the cost of increased
134 memory consumption.
135
136config TEST_KASAN
137 tristate "Module for testing KASAN for bug detection"
138 depends on m && KASAN
139 help
140 This is a test module doing various nasty things like
141 out of bounds accesses, use after free. It is useful for testing
142 kernel debugging features like KASAN.