From: Ard Biesheuvel <ardb@kernel.org>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: linux-efi <linux-efi@vger.kernel.org>, X86 ML <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 5/5] efi/x86: Check for bad relocations
Date: Thu, 16 Apr 2020 09:38:36 +0200 [thread overview]
Message-ID: <CAMj1kXFMMeYUPirY10JJfs31Z5GnHvUe=gLgG6SUJY9uWj588g@mail.gmail.com> (raw)
In-Reply-To: <20200415221520.2692512-6-nivedita@alum.mit.edu>
On Thu, 16 Apr 2020 at 00:15, Arvind Sankar <nivedita@alum.mit.edu> wrote:
>
> Add relocation checking for x86 as well to catch non-PC-relative
> relocations that require runtime processing, since the EFI stub does not
> do any runtime relocation processing.
>
> This will catch, for example, data relocations created by static
> initializers of pointers.
>
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
> ---
> drivers/firmware/efi/libstub/Makefile | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index 0bb2916eb12b..2aff59812a54 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -96,6 +96,8 @@ STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS
> # .bss section here so it's easy to pick out in the linker script.
> #
> STUBCOPY_FLAGS-$(CONFIG_X86) += --rename-section .bss=.bss.efistub,load,alloc
> +STUBCOPY_RELOC-$(CONFIG_X86_32) := 'R_X86_32_(8|16|32)'
This should be R_386_xxx
> +STUBCOPY_RELOC-$(CONFIG_X86_64) := 'R_X86_64_(8|16|32|32S|64)'
>
... and in general, I think we only need the native pointer sized ones, so
R_386_32
R_X86_64_64
> $(obj)/%.stub.o: $(obj)/%.o FORCE
> $(call if_changed,stubcopy)
> @@ -107,16 +109,14 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
> # this time, use objcopy and leave all sections in place.
> #
>
> -cmd_stubrelocs_check-y = /bin/true
> -
> -cmd_stubrelocs_check-$(CONFIG_EFI_ARMSTUB) = \
> +cmd_stubrelocs_check = \
> $(STRIP) --strip-debug -o $@ $<; \
> - if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then \
> + if $(OBJDUMP) -r $@ | grep -E $(STUBCOPY_RELOC-y); then \
... which means we don't need to -E either
> echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
> /bin/false; \
> fi
>
> quiet_cmd_stubcopy = STUBCPY $@
> cmd_stubcopy = \
> - $(cmd_stubrelocs_check-y); \
> + $(cmd_stubrelocs_check); \
> $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
> --
> 2.24.1
>
Could we fold this into the previous x86 patch, and drop the one that
splits off the relocation check from stubcpy?
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next prev parent reply other threads:[~2020-04-16 7:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 22:15 [PATCH 0/5] efi: Remove __efistub_global annotation Arvind Sankar
2020-04-15 22:15 ` [PATCH 1/5] efi/arm: " Arvind Sankar
2020-04-16 7:50 ` Ard Biesheuvel
2020-04-15 22:15 ` [PATCH 2/5] efi/libstub: Factor out relocation checking Arvind Sankar
2020-04-15 22:15 ` [PATCH 3/5] efi/x86: Remove __efistub_global annotation Arvind Sankar
2020-04-16 7:51 ` Ard Biesheuvel
2020-04-15 22:15 ` [PATCH 4/5] efi: Kill __efistub_global Arvind Sankar
2020-04-16 7:51 ` Ard Biesheuvel
2020-04-15 22:15 ` [PATCH 5/5] efi/x86: Check for bad relocations Arvind Sankar
2020-04-16 7:38 ` Ard Biesheuvel [this message]
2020-04-16 14:48 ` Arvind Sankar
2020-04-16 15:12 ` [PATCH v2 0/3] efi: Remove __efistub_global annotation Arvind Sankar
2020-04-16 16:01 ` Ard Biesheuvel
2020-04-16 15:12 ` [PATCH v2 1/3] efi/arm: " Arvind Sankar
2020-04-16 15:12 ` [PATCH v2 2/3] efi/x86: Remove __efistub_global and add relocation check Arvind Sankar
2020-04-16 15:12 ` [PATCH v2 3/3] efi: Kill __efistub_global Arvind Sankar
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