From: Kees Cook <keescook@chromium.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
kernel test robot <lkp@intel.com>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
kbuild-all@lists.01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Subject: Re: lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes
Date: Thu, 27 Aug 2020 11:42:07 -0700 [thread overview]
Message-ID: <202008271138.0FA7400@keescook> (raw)
In-Reply-To: <CAHk-=wgXW=YLxGN0QVpp-1w5GDd2pf1W-FqY15poKzoVfik2qA@mail.gmail.com>
On Thu, Aug 27, 2020 at 10:55:32AM -0700, Linus Torvalds wrote:
> On Thu, Aug 27, 2020 at 10:34 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > How are you guys testing? I have UBSAN and GCOV on, and don't see
> > crazy frames on either i386 or x86-64.
>
> Oh, never mind. I also have COMPILE_TEST on, so it ends up disabling
> GCOV_PROFILE_ALL and UBSAN_SANITIZE_ALL.
>
> And yeah, this seems to be a gcc bug. It generates a ton of stack
> slots for temporaries. It's -fsanitize=object-size that seems to do
> it.
>
> And "-fstack-reuse=all" doesn't seem to make any difference.
>
> So I think
>
> (a) our stack size check is good to catch this
>
> (b) gcc and -fsanitize=object-size is basically an unusable combination
>
> and it's not a bug in the kernel.
Do you mean you checked both gcc and clang and it was only a problem with gcc?
(If so, I can tweak the "depends" below...)
This should let us avoid it, I'm currently testing:
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 774315de555a..24091315c251 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -47,6 +47,19 @@ config UBSAN_BOUNDS
to the {str,mem}*cpy() family of functions (that is addressed
by CONFIG_FORTIFY_SOURCE).
+config UBSAN_OBJECT_SIZE
+ bool "Check for accesses beyond known object sizes"
+ default UBSAN
+ depends on !COMPILE_TEST
+ help
+ This option enables detection of cases where accesses may
+ happen beyond the end of an object's size, which happens in
+ places like invalid downcasts, or calling function pointers
+ through invalid pointers.
+
+ This uses much more stack space, and isn't recommended for
+ cases were stack utilization depth is a concern.
+
config UBSAN_MISC
bool "Enable all other Undefined Behavior sanity checks"
default UBSAN
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index 27348029b2b8..3ff67e9b17fd 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -7,12 +7,15 @@ ifdef CONFIG_UBSAN_BOUNDS
CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds)
endif
+ifdef CONFIG_UBSAN_OBJECT_SIZE
+ CFLAGS_UBSAN += $(call cc-option, -fsanitize=object-size)
+endif
+
ifdef CONFIG_UBSAN_MISC
CFLAGS_UBSAN += $(call cc-option, -fsanitize=shift)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=integer-divide-by-zero)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=unreachable)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=signed-integer-overflow)
- CFLAGS_UBSAN += $(call cc-option, -fsanitize=object-size)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=bool)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=enum)
endif
--
Kees Cook
next prev parent reply other threads:[~2020-08-27 18:42 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 3:52 lib/crypto/chacha.c:65:1: warning: the frame size of 1604 bytes is larger than 1024 bytes kernel test robot
2020-08-27 8:05 ` Herbert Xu
2020-08-27 8:10 ` Ard Biesheuvel
2020-08-27 8:24 ` Herbert Xu
2020-08-27 17:34 ` Linus Torvalds
2020-08-27 17:55 ` Linus Torvalds
2020-08-27 18:42 ` Kees Cook [this message]
2020-08-27 19:02 ` Linus Torvalds
2020-08-27 19:32 ` Kees Cook
2020-08-27 19:11 ` Arnd Bergmann
2020-08-27 19:34 ` Kees Cook
2020-08-27 20:08 ` Linus Torvalds
2020-08-27 8:33 ` Arnd Bergmann
2020-08-27 8:42 ` Ard Biesheuvel
2020-08-27 9:19 ` Arnd Bergmann
2020-08-27 10:41 ` Ard Biesheuvel
2020-08-27 11:51 ` Herbert Xu
2020-08-27 16:25 ` Arnd Bergmann
2020-09-19 17:27 kernel test robot
2020-10-18 19:13 kernel test robot
2020-10-19 15:47 ` Joe Perches
2020-10-20 8:00 ` David Laight
2020-10-20 10:13 ` Joe Perches
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