2019-05-19 20:07:45 +08:00
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# SPDX-License-Identifier: GPL-2.0-only
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2016-01-21 07:00:55 +08:00
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config ARCH_HAS_UBSAN_SANITIZE_ALL
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bool
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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menuconfig UBSAN
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2016-01-21 07:00:55 +08:00
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bool "Undefined behaviour sanity checker"
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help
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2020-04-07 11:12:27 +08:00
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This option enables the Undefined Behaviour sanity checker.
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2016-01-21 07:00:55 +08:00
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Compile-time instrumentation is used to detect various undefined
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2020-04-07 11:12:27 +08:00
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behaviours at runtime. For more details, see:
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Documentation/dev-tools/ubsan.rst
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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if UBSAN
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2020-04-07 11:12:27 +08:00
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config UBSAN_TRAP
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bool "On Sanitizer warnings, abort the running kernel code"
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2020-12-16 12:46:31 +08:00
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depends on !COMPILE_TEST
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2020-04-07 11:12:27 +08:00
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depends on $(cc-option, -fsanitize-undefined-trap-on-error)
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help
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Building kernels with Sanitizer features enabled tends to grow
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the kernel size by around 5%, due to adding all the debugging
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text on failure paths. To avoid this, Sanitizer instrumentation
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can just issue a trap. This reduces the kernel size overhead but
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turns all warnings (including potentially harmless conditions)
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into full exceptions that abort the running kernel code
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(regardless of context, locks held, etc), which may destabilize
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the system. For some system builders this is an acceptable
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trade-off.
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2016-01-21 07:00:55 +08:00
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2020-12-16 12:46:24 +08:00
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config CC_HAS_UBSAN_BOUNDS
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def_bool $(cc-option,-fsanitize=bounds)
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config CC_HAS_UBSAN_ARRAY_BOUNDS
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def_bool $(cc-option,-fsanitize=array-bounds)
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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config UBSAN_BOUNDS
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bool "Perform array index bounds checking"
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default UBSAN
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2020-12-16 12:46:24 +08:00
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depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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help
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This option enables detection of directly indexed out of bounds
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array accesses, where the array size is known at compile time.
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Note that this does not protect array overflows via bad calls
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to the {str,mem}*cpy() family of functions (that is addressed
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by CONFIG_FORTIFY_SOURCE).
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2020-12-16 12:46:24 +08:00
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config UBSAN_ONLY_BOUNDS
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def_bool CC_HAS_UBSAN_BOUNDS && !CC_HAS_UBSAN_ARRAY_BOUNDS
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depends on UBSAN_BOUNDS
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help
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This is a weird case: Clang's -fsanitize=bounds includes
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-fsanitize=local-bounds, but it's trapping-only, so for
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Clang, we must use -fsanitize=array-bounds when we want
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traditional array bounds checking enabled. For GCC, we
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want -fsanitize=bounds.
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config UBSAN_ARRAY_BOUNDS
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def_bool CC_HAS_UBSAN_ARRAY_BOUNDS
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depends on UBSAN_BOUNDS
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2020-10-16 11:13:38 +08:00
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config UBSAN_LOCAL_BOUNDS
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bool "Perform array local bounds checking"
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depends on UBSAN_TRAP
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=local-bounds)
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2020-10-16 11:13:38 +08:00
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help
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This option enables -fsanitize=local-bounds which traps when an
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2020-12-16 12:46:24 +08:00
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exception/error is detected. Therefore, it may only be enabled
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with CONFIG_UBSAN_TRAP.
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2020-10-16 11:13:38 +08:00
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Enabling this option detects errors due to accesses through a
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pointer that is derived from an object of a statically-known size,
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where an added offset (which may not be known statically) is
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out-of-bounds.
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2020-12-16 12:46:24 +08:00
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config UBSAN_SHIFT
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2020-12-16 12:46:39 +08:00
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bool "Perform checking for bit-shift overflows"
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default UBSAN
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=shift)
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2020-12-16 12:46:39 +08:00
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help
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This option enables -fsanitize=shift which checks for bit-shift
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operations that overflow to the left or go switch to negative
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for signed types.
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2020-12-16 12:46:24 +08:00
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config UBSAN_DIV_ZERO
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2020-12-16 12:46:39 +08:00
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bool "Perform checking for integer divide-by-zero"
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=integer-divide-by-zero)
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2020-12-16 12:46:39 +08:00
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help
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This option enables -fsanitize=integer-divide-by-zero which checks
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for integer division by zero. This is effectively redundant with the
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kernel's existing exception handling, though it can provide greater
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debugging information under CONFIG_UBSAN_REPORT_FULL.
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2020-12-16 12:46:24 +08:00
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config UBSAN_UNREACHABLE
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2020-12-16 12:46:39 +08:00
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bool "Perform checking for unreachable code"
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# objtool already handles unreachable checking and gets angry about
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# seeing UBSan instrumentation located in unreachable places.
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depends on !STACK_VALIDATION
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=unreachable)
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2020-12-16 12:46:39 +08:00
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help
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This option enables -fsanitize=unreachable which checks for control
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flow reaching an expected-to-be-unreachable position.
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2020-12-16 12:46:24 +08:00
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config UBSAN_BOOL
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2020-12-16 12:46:39 +08:00
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bool "Perform checking for non-boolean values used as boolean"
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default UBSAN
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=bool)
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2020-12-16 12:46:39 +08:00
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help
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This option enables -fsanitize=bool which checks for boolean values being
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loaded that are neither 0 nor 1.
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2020-12-16 12:46:24 +08:00
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config UBSAN_ENUM
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2020-12-16 12:46:39 +08:00
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bool "Perform checking for out of bounds enum values"
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default UBSAN
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2020-12-16 12:46:24 +08:00
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depends on $(cc-option,-fsanitize=enum)
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2020-12-16 12:46:39 +08:00
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help
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This option enables -fsanitize=enum which checks for values being loaded
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into an enum that are outside the range of given values for the given enum.
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config UBSAN_ALIGNMENT
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bool "Perform checking for misaligned pointer usage"
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default !HAVE_EFFICIENT_UNALIGNED_ACCESS
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depends on !UBSAN_TRAP && !COMPILE_TEST
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depends on $(cc-option,-fsanitize=alignment)
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help
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This option enables the check of unaligned memory accesses.
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Enabling this option on architectures that support unaligned
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accesses may produce a lot of false positives.
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2020-12-16 12:46:24 +08:00
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2016-01-21 07:00:55 +08:00
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config UBSAN_SANITIZE_ALL
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bool "Enable instrumentation for the entire kernel"
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depends on ARCH_HAS_UBSAN_SANITIZE_ALL
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default y
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help
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This option activates instrumentation for the entire kernel.
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If you don't enable this option, you have to explicitly specify
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UBSAN_SANITIZE := y for the files/directories you want to check for UB.
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2016-02-12 08:12:55 +08:00
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Enabling this option will get kernel image size increased
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significantly.
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2016-01-21 07:00:55 +08:00
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2018-04-11 07:32:58 +08:00
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config TEST_UBSAN
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tristate "Module for testing for undefined behavior detection"
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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depends on m
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2018-04-11 07:32:58 +08:00
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help
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This is a test module for UBSAN.
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It triggers various undefined behavior, and detect it.
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ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.
For example, using this, we can start to expand the coverage syzkaller is
providing. Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy. This will let us focus on one feature
at a time.
For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference). In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.
Some notes on the bounds checker:
- it does not instrument {mem,str}*()-family functions, it only
instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
the {mem,str}*()-family functions is a work-in-progress around
CONFIG_FORTIFY_SOURCE[1].
- it ignores flexible array members, including the very old single
byte (e.g. "int foo[1];") declarations. (Note that GCC's
implementation appears to ignore _all_ trailing arrays, but Clang only
ignores empty, 0, and 1 byte arrays[2].)
[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:12:31 +08:00
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endif # if UBSAN
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