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From:   tedheadster <tedheadster@gmail.com>
Date:   Tue, 13 Feb 2018 10:27:29 -0500
Message-ID: <CAP8WD_Yr8bt+uz7JBixf+xELB-_3Y8J8tsaQWpEg8nvFtGFraw@mail.gmail.com>
Subject: Re: move stack-protector availability out of Kconfig
To:     Kees Cook <keescook@chromium.org>
Cc:     akpm@linux-foundation.org, yamada.masahiro@socionext.com,
        Arnd Bergmann <arnd@arndb.de>, josh@joshtriplett.org,
        npiggin@gmail.com, Laura Abbott <labbott@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Kees,
  I have a question about this patch. When I configure a kernel for
ARCH=i386 it sets these Kconfig variables this way:

HAVE_CC_STACKPROTECTOR=y
CC_STACKPROTECTOR_AUTO=y

CC_STACKPROTECTOR_NONE=n
CC_STACKPROTECTOR_REGULAR=n
CC_STACKPROTECTOR_STRONG=n

It seems to me that at least _one_ of the last _three_ variables
should be set to 'y' with the defaults that are being set, probably
CC_STACKPOINTER_NONE=y. All of them being 'n' doesn't make sense to
me.

As a side note, these defaults set X86_32_LAZY_GS=n (depends on X86_32
[=y] && CC_STACKPROTECTOR_NONE [=n]) which causes the x86_32 kernels
to hang. I'll discuss  that in a different email thread, but just
wanted to say how I came upon this.

- Matthew Whitehead