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| 1 | +preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC)) | |
| 2 | + | |
| 3 | +config PLUGIN_HOSTCC | |
| 4 | + string | |
| 5 | + default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" | |
| 6 | + help | |
| 7 | + Host compiler used to build GCC plugins. This can be $(HOSTCXX), | |
| 8 | + $(HOSTCC), or a null string if GCC plugin is unsupported. | |
| 9 | + | |
| 10 | +config HAVE_GCC_PLUGINS | |
| 11 | + bool | |
| 12 | + help | |
| 13 | + An arch should select this symbol if it supports building with | |
| 14 | + GCC plugins. | |
| 15 | + | |
| 16 | +menuconfig GCC_PLUGINS | |
| 17 | + bool "GCC plugins" | |
| 18 | + depends on HAVE_GCC_PLUGINS | |
| 19 | + depends on PLUGIN_HOSTCC != "" | |
| 20 | + help | |
| 21 | + GCC plugins are loadable modules that provide extra features to the | |
| 22 | + compiler. They are useful for runtime instrumentation and static analysis. | |
| 23 | + | |
| 24 | + See Documentation/gcc-plugins.txt for details. | |
| 25 | + | |
| 26 | +if GCC_PLUGINS | |
| 27 | + | |
| 28 | +config GCC_PLUGIN_CYC_COMPLEXITY | |
| 29 | + bool "Compute the cyclomatic complexity of a function" if EXPERT | |
| 30 | + depends on !COMPILE_TEST # too noisy | |
| 31 | + help | |
| 32 | + The complexity M of a function's control flow graph is defined as: | |
| 33 | + M = E - N + 2P | |
| 34 | + where | |
| 35 | + | |
| 36 | + E = the number of edges | |
| 37 | + N = the number of nodes | |
| 38 | + P = the number of connected components (exit nodes). | |
| 39 | + | |
| 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. | |
| 43 | + | |
| 44 | +config GCC_PLUGIN_SANCOV | |
| 45 | + bool | |
| 46 | + help | |
| 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>. | |
| 51 | + | |
| 52 | +config GCC_PLUGIN_LATENT_ENTROPY | |
| 53 | + bool "Generate some entropy during boot and runtime" | |
| 54 | + help | |
| 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 | |
| 60 | + irq processing. | |
| 61 | + | |
| 62 | + Note that entropy extracted this way is not cryptographically | |
| 63 | + secure! | |
| 64 | + | |
| 65 | + This plugin was ported from grsecurity/PaX. More information at: | |
| 66 | + * https://grsecurity.net/ | |
| 67 | + * https://pax.grsecurity.net/ | |
| 68 | + | |
| 69 | +config GCC_PLUGIN_STRUCTLEAK | |
| 70 | + bool "Force initialization of variables containing userspace addresses" | |
| 71 | + # Currently STRUCTLEAK inserts initialization out of live scope of | |
| 72 | + # variables from KASAN point of view. This leads to KASAN false | |
| 73 | + # positive reports. Prohibit this combination for now. | |
| 74 | + depends on !KASAN_EXTRA | |
| 75 | + help | |
| 76 | + This plugin zero-initializes any structures containing a | |
| 77 | + __user attribute. This can prevent some classes of information | |
| 78 | + exposures. | |
| 79 | + | |
| 80 | + This plugin was ported from grsecurity/PaX. More information at: | |
| 81 | + * https://grsecurity.net/ | |
| 82 | + * https://pax.grsecurity.net/ | |
| 83 | + | |
| 84 | +config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL | |
| 85 | + bool "Force initialize all struct type variables passed by reference" | |
| 86 | + depends on GCC_PLUGIN_STRUCTLEAK | |
| 87 | + depends on !COMPILE_TEST | |
| 88 | + help | |
| 89 | + Zero initialize any struct type local variable that may be passed by | |
| 90 | + reference without having been initialized. | |
| 91 | + | |
| 92 | +config GCC_PLUGIN_STRUCTLEAK_VERBOSE | |
| 93 | + bool "Report forcefully initialized variables" | |
| 94 | + depends on GCC_PLUGIN_STRUCTLEAK | |
| 95 | + depends on !COMPILE_TEST # too noisy | |
| 96 | + help | |
| 97 | + This option will cause a warning to be printed each time the | |
| 98 | + structleak plugin finds a variable it thinks needs to be | |
| 99 | + initialized. Since not all existing initializers are detected | |
| 100 | + by the plugin, this can produce false positive warnings. | |
| 101 | + | |
| 102 | +config GCC_PLUGIN_RANDSTRUCT | |
| 103 | + bool "Randomize layout of sensitive kernel structures" | |
| 104 | + select MODVERSIONS if MODULES | |
| 105 | + help | |
| 106 | + If you say Y here, the layouts of structures that are entirely | |
| 107 | + function pointers (and have not been manually annotated with | |
| 108 | + __no_randomize_layout), or structures that have been explicitly | |
| 109 | + marked with __randomize_layout, will be randomized at compile-time. | |
| 110 | + This can introduce the requirement of an additional information | |
| 111 | + exposure vulnerability for exploits targeting these structure | |
| 112 | + types. | |
| 113 | + | |
| 114 | + Enabling this feature will introduce some performance impact, | |
| 115 | + slightly increase memory usage, and prevent the use of forensic | |
| 116 | + tools like Volatility against the system (unless the kernel | |
| 117 | + source tree isn't cleaned after kernel installation). | |
| 118 | + | |
| 119 | + The seed used for compilation is located at | |
| 120 | + scripts/gcc-plgins/randomize_layout_seed.h. It remains after | |
| 121 | + a make clean to allow for external modules to be compiled with | |
| 122 | + the existing seed and will be removed by a make mrproper or | |
| 123 | + make distclean. | |
| 124 | + | |
| 125 | + Note that the implementation requires gcc 4.7 or newer. | |
| 126 | + | |
| 127 | + This plugin was ported from grsecurity/PaX. More information at: | |
| 128 | + * https://grsecurity.net/ | |
| 129 | + * https://pax.grsecurity.net/ | |
| 130 | + | |
| 131 | +config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE | |
| 132 | + bool "Use cacheline-aware structure randomization" | |
| 133 | + depends on GCC_PLUGIN_RANDSTRUCT | |
| 134 | + depends on !COMPILE_TEST # do not reduce test coverage | |
| 135 | + help | |
| 136 | + If you say Y here, the RANDSTRUCT randomization will make a | |
| 137 | + best effort at restricting randomization to cacheline-sized | |
| 138 | + groups of elements. It will further not randomize bitfields | |
| 139 | + in structures. This reduces the performance hit of RANDSTRUCT | |
| 140 | + at the cost of weakened randomization. | |
| 141 | + | |
| 142 | +endif | |