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1# SPDX-License-Identifier: GPL-2.0-only
2config ARCH_HAS_UBSAN_SANITIZE_ALL
3 bool
4
5config UBSAN
6 bool "Undefined behaviour sanity checker"
7 help
8 This option enables undefined behaviour sanity checker
9 Compile-time instrumentation is used to detect various undefined
10 behaviours in runtime. Various types of checks may be enabled
11 via boot parameter ubsan_handle
12 (see: Documentation/dev-tools/ubsan.rst).
13
14config UBSAN_SANITIZE_ALL
15 bool "Enable instrumentation for the entire kernel"
16 depends on UBSAN
17 depends on ARCH_HAS_UBSAN_SANITIZE_ALL
18
19 # We build with -Wno-maybe-uninitilzed, but we still want to
20 # use -Wmaybe-uninitilized in allmodconfig builds.
21 # So dependsy bellow used to disable this option in allmodconfig
22 depends on !COMPILE_TEST
23 default y
24 help
25 This option activates instrumentation for the entire kernel.
26 If you don't enable this option, you have to explicitly specify
27 UBSAN_SANITIZE := y for the files/directories you want to check for UB.
28 Enabling this option will get kernel image size increased
29 significantly.
30
31config UBSAN_NO_ALIGNMENT
32 bool "Disable checking of pointers alignment"
33 depends on UBSAN
34 default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
35 help
36 This option disables the check of unaligned memory accesses.
37 This option should be used when building allmodconfig.
38 Disabling this option on architectures that support unaligned
39 accesses may produce a lot of false positives.
40
41config UBSAN_ALIGNMENT
42 def_bool !UBSAN_NO_ALIGNMENT
43
44config TEST_UBSAN
45 tristate "Module for testing for undefined behavior detection"
46 depends on m && UBSAN
47 help
48 This is a test module for UBSAN.
49 It triggers various undefined behavior, and detect it.
1# SPDX-License-Identifier: GPL-2.0-only
2config ARCH_HAS_UBSAN_SANITIZE_ALL
3 bool
4
5menuconfig UBSAN
6 bool "Undefined behaviour sanity checker"
7 help
8 This option enables the Undefined Behaviour sanity checker.
9 Compile-time instrumentation is used to detect various undefined
10 behaviours at runtime. For more details, see:
11 Documentation/dev-tools/ubsan.rst
12
13if UBSAN
14
15config UBSAN_TRAP
16 bool "On Sanitizer warnings, abort the running kernel code"
17 depends on !COMPILE_TEST
18 depends on $(cc-option, -fsanitize-undefined-trap-on-error)
19 help
20 Building kernels with Sanitizer features enabled tends to grow
21 the kernel size by around 5%, due to adding all the debugging
22 text on failure paths. To avoid this, Sanitizer instrumentation
23 can just issue a trap. This reduces the kernel size overhead but
24 turns all warnings (including potentially harmless conditions)
25 into full exceptions that abort the running kernel code
26 (regardless of context, locks held, etc), which may destabilize
27 the system. For some system builders this is an acceptable
28 trade-off.
29
30config CC_HAS_UBSAN_BOUNDS
31 def_bool $(cc-option,-fsanitize=bounds)
32
33config CC_HAS_UBSAN_ARRAY_BOUNDS
34 def_bool $(cc-option,-fsanitize=array-bounds)
35
36config UBSAN_BOUNDS
37 bool "Perform array index bounds checking"
38 default UBSAN
39 depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS
40 help
41 This option enables detection of directly indexed out of bounds
42 array accesses, where the array size is known at compile time.
43 Note that this does not protect array overflows via bad calls
44 to the {str,mem}*cpy() family of functions (that is addressed
45 by CONFIG_FORTIFY_SOURCE).
46
47config UBSAN_ONLY_BOUNDS
48 def_bool CC_HAS_UBSAN_BOUNDS && !CC_HAS_UBSAN_ARRAY_BOUNDS
49 depends on UBSAN_BOUNDS
50 help
51 This is a weird case: Clang's -fsanitize=bounds includes
52 -fsanitize=local-bounds, but it's trapping-only, so for
53 Clang, we must use -fsanitize=array-bounds when we want
54 traditional array bounds checking enabled. For GCC, we
55 want -fsanitize=bounds.
56
57config UBSAN_ARRAY_BOUNDS
58 def_bool CC_HAS_UBSAN_ARRAY_BOUNDS
59 depends on UBSAN_BOUNDS
60
61config UBSAN_LOCAL_BOUNDS
62 bool "Perform array local bounds checking"
63 depends on UBSAN_TRAP
64 depends on $(cc-option,-fsanitize=local-bounds)
65 help
66 This option enables -fsanitize=local-bounds which traps when an
67 exception/error is detected. Therefore, it may only be enabled
68 with CONFIG_UBSAN_TRAP.
69
70 Enabling this option detects errors due to accesses through a
71 pointer that is derived from an object of a statically-known size,
72 where an added offset (which may not be known statically) is
73 out-of-bounds.
74
75config UBSAN_SHIFT
76 bool "Perform checking for bit-shift overflows"
77 default UBSAN
78 depends on $(cc-option,-fsanitize=shift)
79 help
80 This option enables -fsanitize=shift which checks for bit-shift
81 operations that overflow to the left or go switch to negative
82 for signed types.
83
84config UBSAN_DIV_ZERO
85 bool "Perform checking for integer divide-by-zero"
86 depends on $(cc-option,-fsanitize=integer-divide-by-zero)
87 # https://github.com/ClangBuiltLinux/linux/issues/1657
88 # https://github.com/llvm/llvm-project/issues/56289
89 depends on !CC_IS_CLANG
90 help
91 This option enables -fsanitize=integer-divide-by-zero which checks
92 for integer division by zero. This is effectively redundant with the
93 kernel's existing exception handling, though it can provide greater
94 debugging information under CONFIG_UBSAN_REPORT_FULL.
95
96config UBSAN_UNREACHABLE
97 bool "Perform checking for unreachable code"
98 # objtool already handles unreachable checking and gets angry about
99 # seeing UBSan instrumentation located in unreachable places.
100 depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || HAVE_UACCESS_VALIDATION))
101 depends on $(cc-option,-fsanitize=unreachable)
102 help
103 This option enables -fsanitize=unreachable which checks for control
104 flow reaching an expected-to-be-unreachable position.
105
106config UBSAN_BOOL
107 bool "Perform checking for non-boolean values used as boolean"
108 default UBSAN
109 depends on $(cc-option,-fsanitize=bool)
110 help
111 This option enables -fsanitize=bool which checks for boolean values being
112 loaded that are neither 0 nor 1.
113
114config UBSAN_ENUM
115 bool "Perform checking for out of bounds enum values"
116 default UBSAN
117 depends on $(cc-option,-fsanitize=enum)
118 help
119 This option enables -fsanitize=enum which checks for values being loaded
120 into an enum that are outside the range of given values for the given enum.
121
122config UBSAN_ALIGNMENT
123 bool "Perform checking for misaligned pointer usage"
124 default !HAVE_EFFICIENT_UNALIGNED_ACCESS
125 depends on !UBSAN_TRAP && !COMPILE_TEST
126 depends on $(cc-option,-fsanitize=alignment)
127 help
128 This option enables the check of unaligned memory accesses.
129 Enabling this option on architectures that support unaligned
130 accesses may produce a lot of false positives.
131
132config UBSAN_SANITIZE_ALL
133 bool "Enable instrumentation for the entire kernel"
134 depends on ARCH_HAS_UBSAN_SANITIZE_ALL
135 default y
136 help
137 This option activates instrumentation for the entire kernel.
138 If you don't enable this option, you have to explicitly specify
139 UBSAN_SANITIZE := y for the files/directories you want to check for UB.
140 Enabling this option will get kernel image size increased
141 significantly.
142
143config TEST_UBSAN
144 tristate "Module for testing for undefined behavior detection"
145 depends on m
146 help
147 This is a test module for UBSAN.
148 It triggers various undefined behavior, and detect it.
149
150endif # if UBSAN