From: Kees Cook <keescook@chromium.org> To: Thomas Gleixner <tglx@linutronix.de>, Will Deacon <will@kernel.org> Cc: Kees Cook <keescook@chromium.org>, Arvind Sankar <nivedita@alum.mit.edu>, Nick Desaulniers <ndesaulniers@google.com>, Ard Biesheuvel <ardb@kernel.org>, Fangrui Song <maskray@google.com>, Sedat Dilek <sedat.dilek@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>, Mark Rutland <mark.rutland@arm.com>, Peter Collingbourne <pcc@google.com>, James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@redhat.com>, Russell King <linux@armlinux.org.uk>, Masahiro Yamada <masahiroy@kernel.org>, Nathan Chancellor <natechancellor@gmail.com>, Arnd Bergmann <arnd@arndb.de>, 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 Subject: [PATCH v5 06/36] x86/boot: Remove run-time relocations from head_{32,64}.S Date: Fri, 31 Jul 2020 16:07:50 -0700 [thread overview] Message-ID: <20200731230820.1742553-7-keescook@chromium.org> (raw) In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> From: Arvind Sankar <nivedita@alum.mit.edu> The BFD linker generates run-time relocations for z_input_len and z_output_len, even though they are absolute symbols. This is fixed for binutils-2.35 [1]. Work around this for earlier versions by defining two variables input_len and output_len in addition to the symbols, and use them via position-independent references. This eliminates the last two run-time relocations in the head code and allows us to drop the -z noreloc-overflow flag to the linker. Move the -pie and --no-dynamic-linker LDFLAGS to LDFLAGS_vmlinux instead of KBUILD_LDFLAGS. There shouldn't be anything else getting linked, but this is the more logical location for these flags, and modversions might call the linker if an EXPORT_SYMBOL is left over accidentally in one of the decompressors. [1] https://sourceware.org/bugzilla/show_bug.cgi?id=25754 Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/x86/boot/compressed/Makefile | 12 ++---------- arch/x86/boot/compressed/head_32.S | 17 ++++++++--------- arch/x86/boot/compressed/head_64.S | 4 ++-- arch/x86/boot/compressed/mkpiggy.c | 6 ++++++ 4 files changed, 18 insertions(+), 21 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 489fea16bcfb..7db0102a573d 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -51,16 +51,8 @@ UBSAN_SANITIZE :=n KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE) # Compressed kernel should be built as PIE since it may be loaded at any # address by the bootloader. -ifeq ($(CONFIG_X86_32),y) -KBUILD_LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker) -else -# To build 64-bit compressed kernel as PIE, we disable relocation -# overflow check to avoid relocation overflow error with a new linker -# command-line option, -z noreloc-overflow. -KBUILD_LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \ - && echo "-z noreloc-overflow -pie --no-dynamic-linker") -endif -LDFLAGS_vmlinux := -T +LDFLAGS_vmlinux := $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker) +LDFLAGS_vmlinux += -T hostprogs := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 8c1a4f5610f5..659fad53ca82 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -178,18 +178,17 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) /* * Do the extraction, and jump to the new kernel.. */ - /* push arguments for extract_kernel: */ - pushl $z_output_len /* decompressed length, end of relocs */ + /* push arguments for extract_kernel: */ - pushl %ebp /* output address */ - - pushl $z_input_len /* input_len */ + pushl output_len@GOTOFF(%ebx) /* decompressed length, end of relocs */ + pushl %ebp /* output address */ + pushl input_len@GOTOFF(%ebx) /* input_len */ leal input_data@GOTOFF(%ebx), %eax - pushl %eax /* input_data */ + pushl %eax /* input_data */ leal boot_heap@GOTOFF(%ebx), %eax - pushl %eax /* heap area */ - pushl %esi /* real mode pointer */ - call extract_kernel /* returns kernel location in %eax */ + pushl %eax /* heap area */ + pushl %esi /* real mode pointer */ + call extract_kernel /* returns kernel location in %eax */ addl $24, %esp /* diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 11429092c224..9e46729cf162 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -534,9 +534,9 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) movq %rsi, %rdi /* real mode address */ leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ leaq input_data(%rip), %rdx /* input_data */ - movl $z_input_len, %ecx /* input_len */ + movl input_len(%rip), %ecx /* input_len */ movq %rbp, %r8 /* output target address */ - movl $z_output_len, %r9d /* decompressed length, end of relocs */ + movl output_len(%rip), %r9d /* decompressed length, end of relocs */ call extract_kernel /* returns kernel location in %rax */ popq %rsi diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c index 7e01248765b2..52aa56cdbacc 100644 --- a/arch/x86/boot/compressed/mkpiggy.c +++ b/arch/x86/boot/compressed/mkpiggy.c @@ -60,6 +60,12 @@ int main(int argc, char *argv[]) printf(".incbin \"%s\"\n", argv[1]); printf("input_data_end:\n"); + printf(".section \".rodata\",\"a\",@progbits\n"); + printf(".globl input_len\n"); + printf("input_len:\n\t.long %lu\n", ilen); + printf(".globl output_len\n"); + printf("output_len:\n\t.long %lu\n", (unsigned long)olen); + retval = 0; bail: if (f) -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org> To: Thomas Gleixner <tglx@linutronix.de>, Will Deacon <will@kernel.org> Cc: Kees Cook <keescook@chromium.org>, Arvind Sankar <nivedita@alum.mit.edu>, Nick Desaulniers <ndesaulniers@google.com>, Ard Biesheuvel <ardb@kernel.org>, Fangrui Song <maskray@google.com>, Sedat Dilek <sedat.dilek@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>, Mark Rutland <mark.rutland@arm.com>, Peter Collingbourne <pcc@google.com>, James Morse <james.morse@arm.com>, Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@redhat.com>, Russell King <linux@armlinux.org.uk>, Masahiro Yamada <masahiroy@kernel.org>, Nathan Chancellor <natechancellor@gmail.com>, Arnd Bergmann <arnd@arndb.de>, 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 06/36] x86/boot: Remove run-time relocations from head_{32,64}.S Date: Fri, 31 Jul 2020 16:07:50 -0700 [thread overview] Message-ID: <20200731230820.1742553-7-keescook@chromium.org> (raw) Message-ID: <20200731230750.q79TgM8rMi_QnMTmnM9u2G7bevuum3aDPXaCkfM7f90@z> (raw) In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> From: Arvind Sankar <nivedita@alum.mit.edu> The BFD linker generates run-time relocations for z_input_len and z_output_len, even though they are absolute symbols. This is fixed for binutils-2.35 [1]. Work around this for earlier versions by defining two variables input_len and output_len in addition to the symbols, and use them via position-independent references. This eliminates the last two run-time relocations in the head code and allows us to drop the -z noreloc-overflow flag to the linker. Move the -pie and --no-dynamic-linker LDFLAGS to LDFLAGS_vmlinux instead of KBUILD_LDFLAGS. There shouldn't be anything else getting linked, but this is the more logical location for these flags, and modversions might call the linker if an EXPORT_SYMBOL is left over accidentally in one of the decompressors. [1] https://sourceware.org/bugzilla/show_bug.cgi?id=25754 Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Kees Cook <keescook@chromium.org> --- arch/x86/boot/compressed/Makefile | 12 ++---------- arch/x86/boot/compressed/head_32.S | 17 ++++++++--------- arch/x86/boot/compressed/head_64.S | 4 ++-- arch/x86/boot/compressed/mkpiggy.c | 6 ++++++ 4 files changed, 18 insertions(+), 21 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 489fea16bcfb..7db0102a573d 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -51,16 +51,8 @@ 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. -ifeq ($(CONFIG_X86_32),y) -KBUILD_LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker) -else -# To build 64-bit compressed kernel as PIE, we disable relocation -# overflow check to avoid relocation overflow error with a new linker -# command-line option, -z noreloc-overflow. -KBUILD_LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \ - && echo "-z noreloc-overflow -pie --no-dynamic-linker") -endif -LDFLAGS_vmlinux := -T +LDFLAGS_vmlinux := $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker) +LDFLAGS_vmlinux += -T hostprogs := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 8c1a4f5610f5..659fad53ca82 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -178,18 +178,17 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) /* * Do the extraction, and jump to the new kernel.. */ - /* push arguments for extract_kernel: */ - pushl $z_output_len /* decompressed length, end of relocs */ + /* push arguments for extract_kernel: */ - pushl %ebp /* output address */ - - pushl $z_input_len /* input_len */ + pushl output_len@GOTOFF(%ebx) /* decompressed length, end of relocs */ + pushl %ebp /* output address */ + pushl input_len@GOTOFF(%ebx) /* input_len */ leal input_data@GOTOFF(%ebx), %eax - pushl %eax /* input_data */ + pushl %eax /* input_data */ leal boot_heap@GOTOFF(%ebx), %eax - pushl %eax /* heap area */ - pushl %esi /* real mode pointer */ - call extract_kernel /* returns kernel location in %eax */ + pushl %eax /* heap area */ + pushl %esi /* real mode pointer */ + call extract_kernel /* returns kernel location in %eax */ addl $24, %esp /* diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 11429092c224..9e46729cf162 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -534,9 +534,9 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) movq %rsi, %rdi /* real mode address */ leaq boot_heap(%rip), %rsi /* malloc area for uncompression */ leaq input_data(%rip), %rdx /* input_data */ - movl $z_input_len, %ecx /* input_len */ + movl input_len(%rip), %ecx /* input_len */ movq %rbp, %r8 /* output target address */ - movl $z_output_len, %r9d /* decompressed length, end of relocs */ + movl output_len(%rip), %r9d /* decompressed length, end of relocs */ call extract_kernel /* returns kernel location in %rax */ popq %rsi diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c index 7e01248765b2..52aa56cdbacc 100644 --- a/arch/x86/boot/compressed/mkpiggy.c +++ b/arch/x86/boot/compressed/mkpiggy.c @@ -60,6 +60,12 @@ int main(int argc, char *argv[]) printf(".incbin \"%s\"\n", argv[1]); printf("input_data_end:\n"); + printf(".section \".rodata\",\"a\",@progbits\n"); + printf(".globl input_len\n"); + printf("input_len:\n\t.long %lu\n", ilen); + printf(".globl output_len\n"); + printf("output_len:\n\t.long %lu\n", (unsigned long)olen); + retval = 0; bail: if (f) -- 2.25.1
next prev parent reply other threads:[~2020-07-31 23:07 UTC|newest] Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-31 23:07 [PATCH v5 00/36] Warn on orphan section placement Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 01/36] x86/boot/compressed: Move .got.plt entries out of the .got section Kees Cook 2020-07-31 23:07 ` [PATCH v5 02/36] x86/boot/compressed: Force hidden visibility for all symbol references Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 03/36] x86/boot/compressed: Get rid of GOT fixup code Kees Cook 2020-07-31 23:07 ` [PATCH v5 04/36] x86/boot: Add .text.* to setup.ld Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 05/36] x86/boot: Remove run-time relocations from .head.text code Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:42 ` Nick Desaulniers 2020-07-31 23:42 ` Nick Desaulniers 2020-07-31 23:07 ` Kees Cook [this message] 2020-07-31 23:07 ` [PATCH v5 06/36] x86/boot: Remove run-time relocations from head_{32,64}.S Kees Cook 2020-08-07 18:12 ` Nick Desaulniers 2020-08-07 20:20 ` Arvind Sankar 2020-07-31 23:07 ` [PATCH v5 07/36] x86/boot: Check that there are no run-time relocations Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 08/36] vmlinux.lds.h: Create COMMON_DISCARDS Kees Cook 2020-07-31 23:07 ` [PATCH v5 09/36] vmlinux.lds.h: Add .gnu.version* to COMMON_DISCARDS Kees Cook 2020-07-31 23:07 ` [PATCH v5 10/36] vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 11/36] vmlinux.lds.h: Split ELF_DETAILS from STABS_DEBUG Kees Cook 2020-07-31 23:07 ` [PATCH v5 12/36] vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to ELF_DETAILS Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 13/36] vmlinux.lds.h: add PGO and AutoFDO input sections Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-08-01 3:51 ` Arvind Sankar 2020-08-01 3:51 ` Arvind Sankar 2020-08-01 6:18 ` Kees Cook 2020-08-01 6:18 ` Kees Cook 2020-08-01 17:27 ` Arvind Sankar 2020-08-01 17:27 ` Arvind Sankar 2020-08-03 19:05 ` Andi Kleen 2020-08-03 19:05 ` Andi Kleen 2020-08-03 20:15 ` Arvind Sankar 2020-08-03 20:15 ` Arvind Sankar 2020-08-04 1:19 ` Fāng-ruì Sòng 2020-08-04 1:19 ` Fāng-ruì Sòng 2020-08-04 4:45 ` Andi Kleen 2020-08-04 4:45 ` Andi Kleen 2020-08-04 5:32 ` Fāng-ruì Sòng 2020-08-04 5:32 ` Fāng-ruì Sòng 2020-08-04 16:06 ` Arvind Sankar 2020-08-04 16:06 ` Arvind Sankar 2020-08-21 19:18 ` Kees Cook 2020-07-31 23:07 ` [PATCH v5 14/36] efi/libstub: Disable -mbranch-protection Kees Cook 2020-07-31 23:07 ` [PATCH v5 15/36] arm64/mm: Remove needless section quotes Kees Cook 2020-07-31 23:07 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 16/36] arm64/kernel: Remove needless Call Frame Information annotations Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 17/36] arm64/build: Remove .eh_frame* sections due to unwind tables Kees Cook 2020-07-31 23:08 ` [PATCH v5 18/36] arm64/build: Use common DISCARDS in linker script Kees Cook 2020-07-31 23:08 ` [PATCH v5 19/36] arm64/build: Add missing DWARF sections Kees Cook 2020-07-31 23:08 ` [PATCH v5 20/36] arm64/build: Assert for unwanted sections Kees Cook 2020-07-31 23:08 ` [PATCH v5 21/36] arm64/build: Warn on orphan section placement Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 22/36] arm/build: Refactor linker script headers Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 23/36] arm/build: Explicitly keep .ARM.attributes sections Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-08-03 19:02 ` Nick Desaulniers 2020-08-03 19:02 ` Nick Desaulniers 2020-08-17 22:06 ` Fangrui Song 2020-07-31 23:08 ` [PATCH v5 24/36] arm/build: Add missing sections Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 25/36] arm/build: Warn on orphan section placement Kees Cook 2020-07-31 23:08 ` [PATCH v5 26/36] arm/boot: Handle all sections explicitly Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 27/36] arm/boot: Warn on orphan section placement Kees Cook 2020-07-31 23:08 ` [PATCH v5 28/36] x86/asm: Avoid generating unused kprobe sections Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 29/36] x86/build: Enforce an empty .got.plt section Kees Cook 2020-08-01 2:12 ` Arvind Sankar 2020-08-01 5:32 ` Kees Cook 2020-08-21 17:49 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 30/36] x86/build: Assert for unwanted sections Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 31/36] x86/build: Warn on orphan section placement Kees Cook 2020-07-31 23:08 ` [PATCH v5 32/36] x86/boot/compressed: Reorganize zero-size section asserts Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-08-01 1:47 ` Arvind Sankar 2020-08-01 2:53 ` Arvind Sankar 2020-08-01 2:53 ` Arvind Sankar 2020-08-01 5:36 ` Kees Cook 2020-08-01 17:12 ` Arvind Sankar 2020-08-21 18:24 ` Kees Cook 2020-08-01 5:35 ` Kees Cook 2020-08-01 5:35 ` Kees Cook 2020-08-01 17:00 ` Arvind Sankar 2020-08-21 18:19 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 33/36] x86/boot/compressed: Remove, discard, or assert for unwanted sections Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 34/36] x86/boot/compressed: Add missing debugging sections to output Kees Cook 2020-07-31 23:08 ` Kees Cook 2020-07-31 23:08 ` [PATCH v5 35/36] x86/boot/compressed: Warn on orphan section placement Kees Cook 2020-07-31 23:08 ` [PATCH v5 36/36] arm/build: Assert for unwanted sections Kees Cook
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