1 preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
5 default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC
7 Host compiler used to build GCC plugins. This can be $(HOSTCXX),
8 $(HOSTCC), or a null string if GCC plugin is unsupported.
10 config HAVE_GCC_PLUGINS
13 An arch should select this symbol if it supports building with
16 menuconfig GCC_PLUGINS
18 depends on HAVE_GCC_PLUGINS
19 depends on PLUGIN_HOSTCC != ""
21 GCC plugins are loadable modules that provide extra features to the
22 compiler. They are useful for runtime instrumentation and static analysis.
24 See Documentation/gcc-plugins.txt for details.
28 config GCC_PLUGIN_CYC_COMPLEXITY
29 bool "Compute the cyclomatic complexity of a function" if EXPERT
30 depends on !COMPILE_TEST # too noisy
32 The complexity M of a function's control flow graph is defined as:
36 E = the number of edges
37 N = the number of nodes
38 P = the number of connected components (exit nodes).
40 Enabling this plugin reports the complexity to stderr during the
41 build. It mainly serves as a simple example of how to create a
42 gcc plugin for the kernel.
44 config GCC_PLUGIN_SANCOV
47 This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
48 basic blocks. It supports all gcc versions with plugin support (from
49 gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
50 by Dmitry Vyukov <dvyukov@google.com>.
52 config GCC_PLUGIN_LATENT_ENTROPY
53 bool "Generate some entropy during boot and runtime"
55 By saying Y here the kernel will instrument some kernel code to
56 extract some entropy from both original and artificially created
57 program state. This will help especially embedded systems where
58 there is little 'natural' source of entropy normally. The cost
59 is some slowdown of the boot process (about 0.5%) and fork and
62 Note that entropy extracted this way is not cryptographically
65 This plugin was ported from grsecurity/PaX. More information at:
66 * https://grsecurity.net/
67 * https://pax.grsecurity.net/
69 config GCC_PLUGIN_STRUCTLEAK
70 bool "Zero initialize stack variables"
72 While the kernel is built with warnings enabled for any missed
73 stack variable initializations, this warning is silenced for
74 anything passed by reference to another function, under the
75 occasionally misguided assumption that the function will do
76 the initialization. As this regularly leads to exploitable
77 flaws, this plugin is available to identify and zero-initialize
78 such variables, depending on the chosen level of coverage.
80 This plugin was originally ported from grsecurity/PaX. More
82 * https://grsecurity.net/
83 * https://pax.grsecurity.net/
87 depends on GCC_PLUGIN_STRUCTLEAK
88 default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
90 This chooses the level of coverage over classes of potentially
91 uninitialized variables. The selected class will be
92 zero-initialized before use.
94 config GCC_PLUGIN_STRUCTLEAK_USER
95 bool "structs marked for userspace"
97 Zero-initialize any structures on the stack containing
98 a __user attribute. This can prevent some classes of
99 uninitialized stack variable exploits and information
100 exposures, like CVE-2013-2141:
101 https://git.kernel.org/linus/b9e146d8eb3b9eca
103 config GCC_PLUGIN_STRUCTLEAK_BYREF
104 bool "structs passed by reference"
106 Zero-initialize any structures on the stack that may
107 be passed by reference and had not already been
108 explicitly initialized. This can prevent most classes
109 of uninitialized stack variable exploits and information
110 exposures, like CVE-2017-1000410:
111 https://git.kernel.org/linus/06e7e776ca4d3654
113 config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
114 bool "anything passed by reference"
116 Zero-initialize any stack variables that may be passed
117 by reference and had not already been explicitly
118 initialized. This is intended to eliminate all classes
119 of uninitialized stack variable exploits and information
124 config GCC_PLUGIN_STRUCTLEAK_VERBOSE
125 bool "Report forcefully initialized variables"
126 depends on GCC_PLUGIN_STRUCTLEAK
127 depends on !COMPILE_TEST # too noisy
129 This option will cause a warning to be printed each time the
130 structleak plugin finds a variable it thinks needs to be
131 initialized. Since not all existing initializers are detected
132 by the plugin, this can produce false positive warnings.
134 config GCC_PLUGIN_RANDSTRUCT
135 bool "Randomize layout of sensitive kernel structures"
136 select MODVERSIONS if MODULES
138 If you say Y here, the layouts of structures that are entirely
139 function pointers (and have not been manually annotated with
140 __no_randomize_layout), or structures that have been explicitly
141 marked with __randomize_layout, will be randomized at compile-time.
142 This can introduce the requirement of an additional information
143 exposure vulnerability for exploits targeting these structure
146 Enabling this feature will introduce some performance impact,
147 slightly increase memory usage, and prevent the use of forensic
148 tools like Volatility against the system (unless the kernel
149 source tree isn't cleaned after kernel installation).
151 The seed used for compilation is located at
152 scripts/gcc-plgins/randomize_layout_seed.h. It remains after
153 a make clean to allow for external modules to be compiled with
154 the existing seed and will be removed by a make mrproper or
157 Note that the implementation requires gcc 4.7 or newer.
159 This plugin was ported from grsecurity/PaX. More information at:
160 * https://grsecurity.net/
161 * https://pax.grsecurity.net/
163 config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
164 bool "Use cacheline-aware structure randomization"
165 depends on GCC_PLUGIN_RANDSTRUCT
166 depends on !COMPILE_TEST # do not reduce test coverage
168 If you say Y here, the RANDSTRUCT randomization will make a
169 best effort at restricting randomization to cacheline-sized
170 groups of elements. It will further not randomize bitfields
171 in structures. This reduces the performance hit of RANDSTRUCT
172 at the cost of weakened randomization.
174 config GCC_PLUGIN_STACKLEAK
175 bool "Erase the kernel stack before returning from syscalls"
176 depends on GCC_PLUGINS
177 depends on HAVE_ARCH_STACKLEAK
179 This option makes the kernel erase the kernel stack before
180 returning from system calls. That reduces the information which
181 kernel stack leak bugs can reveal and blocks some uninitialized
182 stack variable attacks.
184 The tradeoff is the performance impact: on a single CPU system kernel
185 compilation sees a 1% slowdown, other systems and workloads may vary
186 and you are advised to test this feature on your expected workload
189 This plugin was ported from grsecurity/PaX. More information at:
190 * https://grsecurity.net/
191 * https://pax.grsecurity.net/
193 config STACKLEAK_TRACK_MIN_SIZE
194 int "Minimum stack frame size of functions tracked by STACKLEAK"
197 depends on GCC_PLUGIN_STACKLEAK
199 The STACKLEAK gcc plugin instruments the kernel code for tracking
200 the lowest border of the kernel stack (and for some other purposes).
201 It inserts the stackleak_track_stack() call for the functions with
202 a stack frame size greater than or equal to this parameter.
203 If unsure, leave the default value 100.
205 config STACKLEAK_METRICS
206 bool "Show STACKLEAK metrics in the /proc file system"
207 depends on GCC_PLUGIN_STACKLEAK
210 If this is set, STACKLEAK metrics for every task are available in
211 the /proc file system. In particular, /proc/<pid>/stack_depth
212 shows the maximum kernel stack consumption for the current and
213 previous syscalls. Although this information is not precise, it
214 can be useful for estimating the STACKLEAK performance impact for
217 config STACKLEAK_RUNTIME_DISABLE
218 bool "Allow runtime disabling of kernel stack erasing"
219 depends on GCC_PLUGIN_STACKLEAK
221 This option provides 'stack_erasing' sysctl, which can be used in
222 runtime to control kernel stack erasing for kernels built with
223 CONFIG_GCC_PLUGIN_STACKLEAK.
225 config GCC_PLUGIN_ARM_SSP_PER_TASK
227 depends on GCC_PLUGINS && ARM