diff options
| author | Andrey Ryabinin <ryabinin.a.a@gmail.com> | 2021-02-25 17:22:42 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-26 09:41:05 -0800 |
| commit | 6aaa31aeb9cf260e1b7155cc11ec864f052db5ec (patch) | |
| tree | 4546f94fd7723de6c3c700b0eac658e910c63e30 /lib/Kconfig.ubsan | |
| parent | d54ce6158e354f5358a547b96299ecd7f3725393 (diff) | |
ubsan: remove overflow checks
Since GCC 8.0 -fsanitize=signed-integer-overflow doesn't work with
-fwrapv. -fwrapv makes signed overflows defines and GCC essentially
disables ubsan checks. On GCC < 8.0 -fwrapv doesn't have influence on
-fsanitize=signed-integer-overflow setting, so it kinda works but
generates false-positves and violates uaccess rules:
lib/iov_iter.o: warning: objtool: iovec_from_user()+0x22d: call to
__ubsan_handle_add_overflow() with UACCESS enabled
Disable signed overflow checks to avoid these problems. Remove unsigned
overflow checks as well. Unsigned overflow appeared as side effect of
commit cdf8a76fda4a ("ubsan: move cc-option tests into Kconfig"), but it
never worked (kernel doesn't boot). And unsigned overflows are allowed by
C standard, so it just pointless.
Link: https://lkml.kernel.org/r/20210209232348.20510-1-ryabinin.a.a@gmail.com
Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/Kconfig.ubsan')
| -rw-r--r-- | lib/Kconfig.ubsan | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 3a0b1c930733..e5372a13511d 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -112,23 +112,6 @@ config UBSAN_UNREACHABLE This option enables -fsanitize=unreachable which checks for control flow reaching an expected-to-be-unreachable position. -config UBSAN_SIGNED_OVERFLOW - bool "Perform checking for signed arithmetic overflow" - default UBSAN - depends on $(cc-option,-fsanitize=signed-integer-overflow) - help - This option enables -fsanitize=signed-integer-overflow which checks - for overflow of any arithmetic operations with signed integers. - -config UBSAN_UNSIGNED_OVERFLOW - bool "Perform checking for unsigned arithmetic overflow" - depends on $(cc-option,-fsanitize=unsigned-integer-overflow) - depends on !X86_32 # avoid excessive stack usage on x86-32/clang - help - This option enables -fsanitize=unsigned-integer-overflow which checks - for overflow of any arithmetic operations with unsigned integers. This - currently causes x86 to fail to boot. - config UBSAN_OBJECT_SIZE bool "Perform checking for accesses beyond the end of objects" default UBSAN |