On Mon, Jun 25, 2018 at 2:23 PM, Joe Perches <joe@xxxxxxxxxxx> wrote: > On Mon, 2018-06-25 at 14:10 -0700, Kees Cook wrote: >> In the quest to remove all stack VLA usage from the kernel[1], this uses >> the maximum blocksize and adds a sanity check. For xcbc, the blocksize >> must always be 16, so use that, since it's already being enforced during >> instantiation. > > Is it time yet to change this warning from 'make W=3' to W=1? > --- > scripts/Makefile.extrawarn | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn > index 8d5357053f86..27ba478d40cd 100644 > --- a/scripts/Makefile.extrawarn > +++ b/scripts/Makefile.extrawarn > @@ -29,6 +29,7 @@ warning-1 += $(call cc-option, -Wmissing-include-dirs) > warning-1 += $(call cc-option, -Wunused-but-set-variable) > warning-1 += $(call cc-option, -Wunused-const-variable) > warning-1 += $(call cc-option, -Wpacked-not-aligned) > +warning-1 += $(call cc-option, -Wvla) > warning-1 += $(call cc-disable-warning, missing-field-initializers) > warning-1 += $(call cc-disable-warning, sign-compare) > > @@ -52,7 +53,6 @@ warning-3 += -Wpointer-arith > warning-3 += -Wredundant-decls > warning-3 += -Wswitch-default > warning-3 += $(call cc-option, -Wpacked-bitfield-compat) > -warning-3 += $(call cc-option, -Wvla) > > warning := $(warning-$(findstring 1, > $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) > warning += $(warning-$(findstring 2, > $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) I was going to skip the churn since I intend to make the default build use -Wvla for the next merge window (assuming we've killed all the VLAs by then). After crypto, only fs/ntfs remains, and I have that half done already. There are a couple more still under some development back-and-forth. I'm not _opposed_ to this change, but I'd rather just make it the default. And then the next cycle, I'd want it to be -Werror=vla, but I may get shouted down. ;) -Kees -- Kees Cook Pixel Security
