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Transfer all previous tests for KASAN to KUnit so they can be run more easily. Using kunit_tool, developers can run these tests with their other KUnit tests and see "pass" or "fail" with the appropriate KASAN report instead of needing to parse each KASAN report to test KASAN functionalities. All KASAN reports are still printed to dmesg. Stack tests do not work properly when KASAN_STACK is enabled so those tests use a check for "if IS_ENABLED(CONFIG_KASAN_STACK)" so they only run if stack instrumentation is enabled. If KASAN_STACK is not enabled, KUnit will print a statement to let the user know this test was not run with KASAN_STACK enabled. copy_user_test and kasan_rcu_uaf cannot be run in KUnit so there is a separate test file for those tests, which can be run as before as a module. [trishalfonso@google.com: v14] Link: https://lkml.kernel.org/r/20200915035828.570483-4-davidgow@google.com Signed-off-by: Patricia Alfonso <trishalfonso@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Brendan Higgins <brendanhiggins@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Shuah Khan <shuah@kernel.org> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20200910070331.3358048-4-davidgow@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
189 lines
6.3 KiB
Text
189 lines
6.3 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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# This config refers to the generic KASAN mode.
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config HAVE_ARCH_KASAN
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bool
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config HAVE_ARCH_KASAN_SW_TAGS
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bool
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config HAVE_ARCH_KASAN_VMALLOC
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bool
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config CC_HAS_KASAN_GENERIC
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def_bool $(cc-option, -fsanitize=kernel-address)
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config CC_HAS_KASAN_SW_TAGS
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def_bool $(cc-option, -fsanitize=kernel-hwaddress)
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config CC_HAS_WORKING_NOSANITIZE_ADDRESS
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def_bool !CC_IS_GCC || GCC_VERSION >= 80300
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menuconfig KASAN
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bool "KASAN: runtime memory debugger"
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depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
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(HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS
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help
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Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
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designed to find out-of-bounds accesses and use-after-free bugs.
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See Documentation/dev-tools/kasan.rst for details.
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if KASAN
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choice
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prompt "KASAN mode"
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default KASAN_GENERIC
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help
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KASAN has two modes: generic KASAN (similar to userspace ASan,
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x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
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software tag-based KASAN (a version based on software memory
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tagging, arm64 only, similar to userspace HWASan, enabled with
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CONFIG_KASAN_SW_TAGS).
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Both generic and tag-based KASAN are strictly debugging features.
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config KASAN_GENERIC
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bool "Generic mode"
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depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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Enables generic KASAN mode.
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This mode is supported in both GCC and Clang. With GCC it requires
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version 8.3.0 or later. Any supported Clang version is compatible,
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but detection of out-of-bounds accesses for global variables is
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supported only since Clang 11.
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This mode consumes about 1/8th of available memory at kernel start
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and introduces an overhead of ~x1.5 for the rest of the allocations.
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The performance slowdown is ~x3.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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config KASAN_SW_TAGS
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bool "Software tag-based mode"
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depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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Enables software tag-based KASAN mode.
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This mode requires Top Byte Ignore support by the CPU and therefore
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is only supported for arm64. This mode requires Clang.
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This mode consumes about 1/16th of available memory at kernel start
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and introduces an overhead of ~20% for the rest of the allocations.
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This mode may potentially introduce problems relating to pointer
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casting and comparison, as it embeds tags into the top byte of each
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pointer.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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endchoice
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choice
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prompt "Instrumentation type"
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default KASAN_OUTLINE
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config KASAN_OUTLINE
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bool "Outline instrumentation"
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help
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Before every memory access compiler insert function call
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__asan_load*/__asan_store*. These functions performs check
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of shadow memory. This is slower than inline instrumentation,
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however it doesn't bloat size of kernel's .text section so
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much as inline does.
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config KASAN_INLINE
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bool "Inline instrumentation"
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help
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Compiler directly inserts code checking shadow memory before
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memory accesses. This is faster than outline (in some workloads
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it gives about x2 boost over outline instrumentation), but
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make kernel's .text size much bigger.
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endchoice
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config KASAN_STACK_ENABLE
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bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
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help
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The LLVM stack address sanitizer has a know problem that
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causes excessive stack usage in a lot of functions, see
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https://bugs.llvm.org/show_bug.cgi?id=38809
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Disabling asan-stack makes it safe to run kernels build
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with clang-8 with KASAN enabled, though it loses some of
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the functionality.
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This feature is always disabled when compile-testing with clang
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to avoid cluttering the output in stack overflow warnings,
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but clang users can still enable it for builds without
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CONFIG_COMPILE_TEST. On gcc it is assumed to always be safe
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to use and enabled by default.
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config KASAN_STACK
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int
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default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
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default 0
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config KASAN_S390_4_LEVEL_PAGING
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bool "KASan: use 4-level paging"
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depends on S390
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help
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Compiling the kernel with KASan disables automatic 3-level vs
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4-level paging selection. 3-level paging is used by default (up
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to 3TB of RAM with KASan enabled). This options allows to force
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4-level paging instead.
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config KASAN_SW_TAGS_IDENTIFY
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bool "Enable memory corruption identification"
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depends on KASAN_SW_TAGS
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help
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This option enables best-effort identification of bug type
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(use-after-free or out-of-bounds) at the cost of increased
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memory consumption.
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config KASAN_VMALLOC
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bool "Back mappings in vmalloc space with real shadow memory"
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depends on HAVE_ARCH_KASAN_VMALLOC
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help
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By default, the shadow region for vmalloc space is the read-only
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zero page. This means that KASAN cannot detect errors involving
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vmalloc space.
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Enabling this option will hook in to vmap/vmalloc and back those
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mappings with real shadow memory allocated on demand. This allows
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for KASAN to detect more sorts of errors (and to support vmapped
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stacks), but at the cost of higher memory usage.
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config KASAN_KUNIT_TEST
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tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS
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depends on KASAN && KUNIT
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default KUNIT_ALL_TESTS
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help
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This is a KUnit test suite doing various nasty things like
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out of bounds and use after free accesses. It is useful for testing
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kernel debugging features like KASAN.
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For more information on KUnit and unit tests in general, please refer
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to the KUnit documentation in Documentation/dev-tools/kunit
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config TEST_KASAN_MODULE
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tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
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depends on m && KASAN
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help
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This is a part of the KASAN test suite that is incompatible with
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KUnit. Currently includes tests that do bad copy_from/to_user
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accesses.
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endif # KASAN
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