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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id m190sm9732049pfm.89.2020.07.31.16.08.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 16:08:35 -0700 (PDT) From: Kees Cook To: Thomas Gleixner , Will Deacon Cc: Kees Cook , Arvind Sankar , Nick Desaulniers , Ard Biesheuvel , Fangrui Song , Sedat Dilek , Catalin Marinas , Mark Rutland , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 07/36] x86/boot: Check that there are no run-time relocations Date: Fri, 31 Jul 2020 16:07:51 -0700 Message-Id: <20200731230820.1742553-8-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> References: <20200731230820.1742553-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arvind Sankar 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: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Ard Biesheuvel Reviewed-by: Fangrui Song Reviewed-by: Sedat Dilek Tested-by: Sedat Dilek Signed-off-by: Arvind Sankar Signed-off-by: Kees Cook --- 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 7db0102a573d..96d53e300ab6 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_MIXED) += $(obj)/efi_thunk_$(BITS).o efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a -# 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) $(efi-obj-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!") -- 2.25.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH v5 07/36] x86/boot: Check that there are no run-time relocations Date: Fri, 31 Jul 2020 16:07:51 -0700 Message-ID: <20200731230820.1742553-8-keescook@chromium.org> References: <20200731230820.1742553-1-keescook@chromium.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner , Will Deacon Cc: Kees Cook , Arvind Sankar , Nick Desaulniers , Ard Biesheuvel , Fangrui Song , Sedat Dilek , Catalin Marinas , Mark Rutland , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.ker List-Id: linux-arch.vger.kernel.org From: Arvind Sankar 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: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Ard Biesheuvel Reviewed-by: Fangrui Song Reviewed-by: Sedat Dilek Tested-by: Sedat Dilek Signed-off-by: Arvind Sankar Signed-off-by: Kees Cook --- 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 7db0102a573d..96d53e300ab6 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_MIXED) += $(obj)/efi_thunk_$(BITS).o efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a -# 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) $(efi-obj-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!") -- 2.25.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB07EC433DF for ; Fri, 31 Jul 2020 23:11:16 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 71337205CB for ; 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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id m190sm9732049pfm.89.2020.07.31.16.08.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 16:08:35 -0700 (PDT) From: Kees Cook To: Thomas Gleixner , Will Deacon Subject: [PATCH v5 07/36] x86/boot: Check that there are no run-time relocations Date: Fri, 31 Jul 2020 16:07:51 -0700 Message-Id: <20200731230820.1742553-8-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> References: <20200731230820.1742553-1-keescook@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200731_190841_434869_9E4700BE X-CRM114-Status: GOOD ( 18.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-efi@vger.kernel.org, Catalin Marinas , Arvind Sankar , Ard Biesheuvel , linux-arch@vger.kernel.org, Fangrui Song , Masahiro Yamada , x86@kernel.org, Russell King , clang-built-linux@googlegroups.com, Ingo Molnar , Borislav Petkov , Kees Cook , Arnd Bergmann , Sedat Dilek , Nathan Chancellor , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, Nick Desaulniers , linux-kernel@vger.kernel.org, James Morse Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Arvind Sankar 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: Nick Desaulniers Reviewed-by: Kees Cook Reviewed-by: Ard Biesheuvel Reviewed-by: Fangrui Song Reviewed-by: Sedat Dilek Tested-by: Sedat Dilek Signed-off-by: Arvind Sankar Signed-off-by: Kees Cook --- 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 7db0102a573d..96d53e300ab6 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_MIXED) += $(obj)/efi_thunk_$(BITS).o efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a -# 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) $(efi-obj-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!") -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel