diff options
| author | George Popescu <georgepope@android.com> | 2020-10-15 20:13:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-16 11:11:22 -0700 |
| commit | 6a6155f664e31c9be43cd690541a9a682ba3dc22 (patch) | |
| tree | aefade86b74d129bd319a46ddc9241dd56d61cf3 /lib | |
| parent | 5cf53f3ce3b9ff5321b56f9ed9d90d59307be7d0 (diff) | |
ubsan: introduce CONFIG_UBSAN_LOCAL_BOUNDS for Clang
When the kernel is compiled with Clang, -fsanitize=bounds expands to
-fsanitize=array-bounds and -fsanitize=local-bounds.
Enabling -fsanitize=local-bounds with Clang has the unfortunate
side-effect of inserting traps; this goes back to its original intent,
which was as a hardening and not a debugging feature [1]. The same
feature made its way into -fsanitize=bounds, but the traps remained. For
that reason, -fsanitize=bounds was split into 'array-bounds' and
'local-bounds' [2].
Since 'local-bounds' doesn't behave like a normal sanitizer, enable it
with Clang only if trapping behaviour was requested by
CONFIG_UBSAN_TRAP=y.
Add the UBSAN_BOUNDS_LOCAL config to Kconfig.ubsan to enable the
'local-bounds' option by default when UBSAN_TRAP is enabled.
[1] http://lists.llvm.org/pipermail/llvm-dev/2012-May/049972.html
[2] http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20131021/091536.html
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: George Popescu <georgepope@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Brazdil <dbrazdil@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lkml.kernel.org/r/20200922074330.2549523-1-georgepope@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.ubsan | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 774315de555a..58f8d03d037b 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -47,6 +47,20 @@ config UBSAN_BOUNDS to the {str,mem}*cpy() family of functions (that is addressed by CONFIG_FORTIFY_SOURCE). +config UBSAN_LOCAL_BOUNDS + bool "Perform array local bounds checking" + depends on UBSAN_TRAP + depends on CC_IS_CLANG + depends on !UBSAN_KCOV_BROKEN + help + This option enables -fsanitize=local-bounds which traps when an + exception/error is detected. Therefore, it should be enabled only + if trapping is expected. + Enabling this option detects errors due to accesses through a + pointer that is derived from an object of a statically-known size, + where an added offset (which may not be known statically) is + out-of-bounds. + config UBSAN_MISC bool "Enable all other Undefined Behavior sanity checks" default UBSAN |