From: Arvind Sankar <nivedita@alum.mit.edu>
To: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Fangrui Song <maskray@google.com>,
Dmitry Golovin <dima@golovin.in>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Daniel Kiper <daniel.kiper@oracle.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
Nathan Chancellor <natechancellor@gmail.com>,
Arnd Bergmann <arnd@arndb.de>, "H . J . Lu" <hjl@sourceware.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 7/7] x86/boot: Check that there are no runtime relocations
Date: Mon, 29 Jun 2020 12:56:03 -0400 [thread overview]
Message-ID: <20200629165603.GD900899@rani.riverdale.lan> (raw)
In-Reply-To: <202006290919.93C759C62@keescook>
On Mon, Jun 29, 2020 at 09:20:31AM -0700, Kees Cook wrote:
> On Mon, Jun 29, 2020 at 06:11:59PM +0200, Ard Biesheuvel wrote:
> > On Mon, 29 Jun 2020 at 18:09, Kees Cook <keescook@chromium.org> wrote:
> > >
> > > On Mon, Jun 29, 2020 at 10:09:28AM -0400, Arvind Sankar wrote:
> > > > Add a linker script check that there are no runtime relocations, and
> > > > remove the old one that tries to check via looking for specially-named
> > > > sections in the object files.
> > > >
> > > > Drop the tests for -fPIE compiler option and -pie linker option, as they
> > > > are available in all supported gcc and binutils versions (as well as
> > > > clang and lld).
> > > >
> > > > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > > > Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
> > > > Reviewed-by: Fangrui Song <maskray@google.com>
> > > > ---
> > > > arch/x86/boot/compressed/Makefile | 28 +++-----------------------
> > > > arch/x86/boot/compressed/vmlinux.lds.S | 8 ++++++++
> > > > 2 files changed, 11 insertions(+), 25 deletions(-)
> > >
> > > Reviewed-by: Kees Cook <keescook@chromium.org>
> > >
> > > question below ...
> > >
> > > > diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
> > > > index a4a4a59a2628..a78510046eec 100644
> > > > --- a/arch/x86/boot/compressed/vmlinux.lds.S
> > > > +++ b/arch/x86/boot/compressed/vmlinux.lds.S
> > > > @@ -42,6 +42,12 @@ SECTIONS
> > > > *(.rodata.*)
> > > > _erodata = . ;
> > > > }
> > > > + .rel.dyn : {
> > > > + *(.rel.*)
> > > > + }
> > > > + .rela.dyn : {
> > > > + *(.rela.*)
> > > > + }
> > > > .got : {
> > > > *(.got)
> > > > }
> > >
> > > Should these be marked (INFO) as well?
> > >
> >
> > Given that sections marked as (INFO) will still be emitted into the
> > ELF image, it does not really make a difference to do this for zero
> > sized sections.
>
> Oh, I misunderstood -- I though they were _not_ emitted; I see now what
> you said was not allocated. So, disk space used for the .got.plt case,
> but not memory space used. Sorry for the confusion!
>
> -Kees
In the case of the REL[A] and .got sections, they are actually already
not emitted at all into the ELF file now that they are zero size.
For .got.plt, it is only emitted for 32-bit (with the 3 reserved
entries), the 64-bit linker seems to get rid of it.
next prev parent reply other threads:[~2020-06-29 19:22 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 14:09 [PATCH v3 0/7] x86/boot: Remove runtime relocations from compressed kernel Arvind Sankar
2020-06-29 14:09 ` [PATCH v3 1/7] x86/boot/compressed: Move .got.plt entries out of the .got section Arvind Sankar
2020-06-29 15:48 ` Kees Cook
2020-06-29 15:50 ` Arvind Sankar
2020-06-29 15:51 ` Ard Biesheuvel
2020-06-29 16:10 ` Kees Cook
2020-06-29 14:09 ` [PATCH v3 2/7] x86/boot/compressed: Force hidden visibility for all symbol references Arvind Sankar
2020-06-29 15:50 ` Kees Cook
2020-07-14 9:20 ` Sedat Dilek
2020-07-14 9:47 ` Ard Biesheuvel
2020-06-29 14:09 ` [PATCH v3 3/7] x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar
2020-06-29 15:53 ` Kees Cook
2020-06-29 14:09 ` [PATCH v3 4/7] x86/boot: Add .text.* to setup.ld Arvind Sankar
2020-06-29 15:55 ` Kees Cook
2020-06-29 14:09 ` [PATCH v3 5/7] x86/boot: Remove run-time relocations from .head.text code Arvind Sankar
2020-06-29 16:04 ` Kees Cook
2020-06-29 17:01 ` Arvind Sankar
2020-07-14 13:20 ` Sedat Dilek
2020-06-29 14:09 ` [PATCH v3 6/7] x86/boot: Remove runtime relocations from head_{32,64}.S Arvind Sankar
2020-06-29 16:06 ` Kees Cook
2020-06-29 16:52 ` Arvind Sankar
2020-06-29 14:09 ` [PATCH v3 7/7] x86/boot: Check that there are no runtime relocations Arvind Sankar
2020-06-29 16:09 ` Kees Cook
2020-06-29 16:11 ` Ard Biesheuvel
2020-06-29 16:20 ` Kees Cook
2020-06-29 16:56 ` Arvind Sankar [this message]
2020-06-29 17:37 ` Fangrui Song
2020-06-29 18:11 ` Ard Biesheuvel
2020-06-29 23:34 ` Fangrui Song
2020-06-30 16:26 ` Ard Biesheuvel
2020-06-30 17:54 ` Arvind Sankar
2020-06-30 22:00 ` Fangrui Song
2020-06-30 23:27 ` Arvind Sankar
2020-07-01 6:44 ` Ard Biesheuvel
2020-07-01 14:42 ` Arvind Sankar
2020-06-29 18:43 ` Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 0/7] x86/boot: Remove runtime relocations from compressed kernel Arvind Sankar
2020-07-14 13:15 ` Sedat Dilek
2020-07-14 14:15 ` Arvind Sankar
2020-07-14 18:13 ` Sedat Dilek
2020-07-14 18:30 ` Sedat Dilek
2020-07-14 18:33 ` Sedat Dilek
2020-07-14 19:21 ` Sedat Dilek
2020-07-14 19:29 ` Arvind Sankar
2020-07-14 19:53 ` Sedat Dilek
2020-07-14 20:07 ` Arvind Sankar
2020-07-14 20:10 ` Sedat Dilek
2020-07-14 20:14 ` Arvind Sankar
2020-07-14 20:17 ` Sedat Dilek
2020-07-14 20:08 ` Sedat Dilek
2020-07-14 20:21 ` Arvind Sankar
2020-07-14 20:24 ` Sedat Dilek
2020-07-14 20:27 ` Sedat Dilek
2020-07-14 20:35 ` Arvind Sankar
2020-07-14 20:43 ` Sedat Dilek
2020-07-14 21:07 ` Arvind Sankar
2020-07-14 20:33 ` Arvind Sankar
2020-07-15 0:41 ` [PATCH v5 0/7] x86/boot: Remove run-time " Arvind Sankar
2020-07-15 1:46 ` Sedat Dilek
2020-07-15 7:11 ` Sedat Dilek
2020-07-17 13:46 ` Arvind Sankar
2020-07-17 18:16 ` Nick Desaulniers
2020-07-17 18:21 ` Sedat Dilek
2020-07-17 20:17 ` [PATCH-next " Arvind Sankar
2020-07-17 23:46 ` Nick Desaulniers
2020-07-29 22:04 ` Kees Cook
2020-07-29 22:23 ` Arvind Sankar
2020-07-30 2:38 ` Kees Cook
2020-07-17 20:17 ` [PATCH-next v5 1/7] x86/boot/compressed: Move .got.plt entries out of the .got section Arvind Sankar
2020-07-17 20:17 ` [PATCH-next v5 2/7] x86/boot/compressed: Force hidden visibility for all symbol references Arvind Sankar
2020-07-17 20:17 ` [PATCH-next v5 3/7] x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar
2020-07-17 20:17 ` [PATCH-next v5 4/7] x86/boot: Add .text.* to setup.ld Arvind Sankar
2020-07-17 20:17 ` [PATCH-next v5 5/7] x86/boot: Remove run-time relocations from .head.text code Arvind Sankar
2020-07-17 20:18 ` [PATCH-next v5 6/7] x86/boot: Remove run-time relocations from head_{32,64}.S Arvind Sankar
2020-07-17 20:18 ` [PATCH-next v5 7/7] x86/boot: Check that there are no run-time relocations Arvind Sankar
2020-07-18 5:44 ` [PATCH v5 0/7] x86/boot: Remove run-time relocations from compressed kernel Ard Biesheuvel
2020-07-18 7:01 ` Sedat Dilek
2020-07-24 23:25 ` Kees Cook
2020-07-31 14:53 ` Arvind Sankar
2020-07-31 14:58 ` Sedat Dilek
2020-07-31 20:27 ` [PATCH v6 " Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 1/7] x86/boot/compressed: Move .got.plt entries out of the .got section Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 2/7] x86/boot/compressed: Force hidden visibility for all symbol references Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 3/7] x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 4/7] x86/boot: Add .text.* to setup.ld Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 5/7] x86/boot: Remove run-time relocations from .head.text code Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 6/7] x86/boot: Remove run-time relocations from head_{32,64}.S Arvind Sankar
2020-07-31 20:27 ` [PATCH v6 7/7] x86/boot: Check that there are no run-time relocations Arvind Sankar
2020-07-31 23:15 ` [PATCH v6 0/7] x86/boot: Remove run-time relocations from compressed kernel Kees Cook
2020-07-15 0:41 ` [PATCH v5 1/7] x86/boot/compressed: Move .got.plt entries out of the .got section Arvind Sankar
2020-07-15 8:52 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 2/7] x86/boot/compressed: Force hidden visibility for all symbol references Arvind Sankar
2020-07-15 8:54 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 3/7] x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar
2020-07-15 8:54 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 4/7] x86/boot: Add .text.* to setup.ld Arvind Sankar
2020-07-15 8:55 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 5/7] x86/boot: Remove run-time relocations from .head.text code Arvind Sankar
2020-07-15 8:56 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 6/7] x86/boot: Remove run-time relocations from head_{32,64}.S Arvind Sankar
2020-07-15 8:58 ` Sedat Dilek
2020-07-15 9:03 ` Ard Biesheuvel
2020-07-15 9:10 ` Sedat Dilek
2020-07-15 0:41 ` [PATCH v5 7/7] x86/boot: Check that there are no run-time relocations Arvind Sankar
2020-07-15 9:00 ` Sedat Dilek
2020-07-15 9:12 ` Sedat Dilek
2020-07-14 2:38 ` [PATCH v4 1/7] x86/boot/compressed: Move .got.plt entries out of the .got section Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 2/7] x86/boot/compressed: Force hidden visibility for all symbol references Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 3/7] x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 4/7] x86/boot: Add .text.* to setup.ld Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 5/7] x86/boot: Remove run-time relocations from .head.text code Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 6/7] x86/boot: Remove runtime relocations from head_{32,64}.S Arvind Sankar
2020-07-14 2:38 ` [PATCH v4 7/7] x86/boot: Check that there are no runtime relocations Arvind Sankar
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