On Wed, 16 Sep 2020 at 09:40, George Popescu <georgepope@xxxxxxxxxx> wrote: > > On Tue, Sep 15, 2020 at 07:32:28PM +0200, Marco Elver wrote: > > On Tue, 15 Sep 2020 at 14:01, George Popescu <georgepope@xxxxxxxxxx> wrote: > > > > > > On Tue, Sep 15, 2020 at 01:18:11PM +0200, Marco Elver wrote: > > > > On Tue, 15 Sep 2020 at 12:25, George Popescu <georgepope@xxxxxxxxxx> wrote: > > > > > On Mon, Sep 14, 2020 at 03:13:14PM -0700, Kees Cook wrote: > > > > > > On Mon, Sep 14, 2020 at 05:27:42PM +0000, George-Aurelian Popescu wrote: > > > > > > > From: George Popescu <georgepope@xxxxxxxxxx> > > > > > > > > > > > > > > When the kernel is compiled with Clang, UBSAN_BOUNDS inserts a brk after > > > > > > > the handler call, preventing it from printing any information processed > > > > > > > inside the buffer. > > > > > > > For Clang -fsanitize=bounds expands to -fsanitize=array-bounds and > > > > > > > -fsanitize=local-bounds, and the latter adds a brk after the handler > > > > > > > call > > > > > > > > > > > This would mean losing the local-bounds coverage. I tried to test it without > > > > > local-bounds and with a locally defined array on the stack and it works fine > > > > > (the handler is called and the error reported). For me it feels like > > > > > --array-bounds and --local-bounds are triggered for the same type of > > > > > undefined_behaviours but they are handling them different. > > > > > > > > Does -fno-sanitize-trap=bounds help?> > > > > > > I tried replacing it with: > > > ifdef CONFIG_CC_IS_CLANG > > > CFLAGS_UBSAN += $(call cc-option, -fno-sanitize-trap=bounds) > > > CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds) > > > else > > > CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds) > > > endif > > > > > > The code traps. > > > > What's your config? Do you have CONFIG_UBSAN_TRAP=y? If so, you have 2 > > options: honor UBSAN_TRAP and crash the kernel, or have a > > 'CFLAGS_REMOVE_... = -fsanitize-undefined-trap-on-error' for the files > > where you can't deal with traps> > > I don't have CONFIG_UBSAN_TRAP=y. My .config is: > CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y > CONFIG_UBSAN=y > # CONFIG_UBSAN_TRAP is not set > CONFIG_UBSAN_KCOV_BROKEN=y > CONFIG_UBSAN_MISC=y > CONFIG_UBSAN_SANITIZE_ALL=y > # CONFIG_UBSAN_ALIGNMENT is not set > CONFIG_TEST_UBSAN=m Your full config would be good, because it includes compiler version etc.
