From: Sedat Dilek <sedat.dilek@gmail.com>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Nick Desaulniers <ndesaulniers@google.com>,
Fangrui Song <maskray@google.com>,
Dmitry Golovin <dima@golovin.in>,
Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
Ard Biesheuvel <ardb@kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Daniel Kiper <daniel.kiper@oracle.com>,
Kees Cook <keescook@chromium.org>,
Nathan Chancellor <natechancellor@gmail.com>,
Arnd Bergmann <arnd@arndb.de>, "H . J . Lu" <hjl@sourceware.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 7/7] x86/boot: Check that there are no run-time relocations
Date: Wed, 15 Jul 2020 11:12:14 +0200 [thread overview]
Message-ID: <CA+icZUVJLreLhESAhd2AMyPOJF9bqUqqJ2PR6Qw5Y3ae4se1eQ@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUX56cEjdkiuxOXtCgY1F0NWD5QxqMBRQxE5Li3=RUe-7w@mail.gmail.com>
On Wed, Jul 15, 2020 at 11:00 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Wed, Jul 15, 2020 at 2:41 AM Arvind Sankar <nivedita@alum.mit.edu> wrote:
> >
> > Add a linker script check that there are no run-time 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).
> >
>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
>
> Here I reported the breakage with LLD and tested the move to
> LDFLAGS_vmlinux with a previous version of the patch.
>
Feel free to also add my:
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
- Sedat -
>
> > Reviewed-by: Kees Cook <keescook@chromium.org>
> > Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
> > Reviewed-by: Fangrui Song <maskray@google.com>
> > Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> > ---
> > arch/x86/boot/compressed/Makefile | 28 +++-----------------------
> > arch/x86/boot/compressed/vmlinux.lds.S | 8 ++++++++
> > 2 files changed, 11 insertions(+), 25 deletions(-)
> >
> > diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> > index ae2c0dc98a6a..a9e082b8c720 100644
> > --- a/arch/x86/boot/compressed/Makefile
> > +++ b/arch/x86/boot/compressed/Makefile
> > @@ -29,7 +29,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
> > vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4
> >
> > KBUILD_CFLAGS := -m$(BITS) -O2
> > -KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC)
> > +KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
> > KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
> > cflags-$(CONFIG_X86_32) := -march=i386
> > cflags-$(CONFIG_X86_64) := -mcmodel=small
> > @@ -51,7 +51,7 @@ UBSAN_SANITIZE :=n
> > KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
> > # Compressed kernel should be built as PIE since it may be loaded at any
> > # address by the bootloader.
> > -LDFLAGS_vmlinux := $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker)
> > +LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
> > LDFLAGS_vmlinux += -T
> >
> > hostprogs := mkpiggy
> > @@ -86,30 +86,8 @@ vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o
> > vmlinux-objs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
> > vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o
> >
> > -# The compressed kernel is built with -fPIC/-fPIE so that a boot loader
> > -# can place it anywhere in memory and it will still run. However, since
> > -# it is executed as-is without any ELF relocation processing performed
> > -# (and has already had all relocation sections stripped from the binary),
> > -# none of the code can use data relocations (e.g. static assignments of
> > -# pointer values), since they will be meaningless at runtime. This check
> > -# will refuse to link the vmlinux if any of these relocations are found.
> > -quiet_cmd_check_data_rel = DATAREL $@
> > -define cmd_check_data_rel
> > - for obj in $(filter %.o,$^); do \
> > - $(READELF) -S $$obj | grep -qF .rel.local && { \
> > - echo "error: $$obj has data relocations!" >&2; \
> > - exit 1; \
> > - } || true; \
> > - done
> > -endef
> > -
> > -# We need to run two commands under "if_changed", so merge them into a
> > -# single invocation.
> > -quiet_cmd_check-and-link-vmlinux = LD $@
> > - cmd_check-and-link-vmlinux = $(cmd_check_data_rel); $(cmd_ld)
> > -
> > $(obj)/vmlinux: $(vmlinux-objs-y) FORCE
> > - $(call if_changed,check-and-link-vmlinux)
> > + $(call if_changed,ld)
> >
> > OBJCOPYFLAGS_vmlinux.bin := -R .comment -S
> > $(obj)/vmlinux.bin: vmlinux FORCE
> > diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
> > index a4a4a59a2628..29df99b6cc64 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)
> > }
> > @@ -85,3 +91,5 @@ ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, "Unexpected GOT/PLT en
> > #else
> > ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0xc, "Unexpected GOT/PLT entries detected!")
> > #endif
> > +
> > +ASSERT(SIZEOF(.rel.dyn) == 0 && SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations detected!")
> > --
> > 2.26.2
> >
next prev parent reply other threads:[~2020-07-15 9:12 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
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 [this message]
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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