From aff69273af61f5d1c8fb401d6f19148d11629b41 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Fri, 10 Mar 2023 19:07:50 +0000 Subject: [PATCH] vdso: Improve cmd_vdso_check to check all dynamic relocations The actual intention is that no dynamic relocation exists in the VDSO. For this the VDSO build validates that the resulting .so file does not have any relocations which are specified via $(ARCH_REL_TYPE_ABS) per architecture, which is fragile as e.g. ARM64 lacks an entry for R_AARCH64_RELATIVE. Aside of that ARCH_REL_TYPE_ABS is a misnomer as it checks for relative relocations too. However, some GNU ld ports produce unneeded R_*_NONE relocation entries. If a port fails to determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE relocations. E.g. ld's powerpc port recently fixed https://sourceware.org/bugzilla/show_bug.cgi?id=29540). R_*_NONE are generally a no-op in the dynamic loaders. So just ignore them. Remove the ARCH_REL_TYPE_ABS defines and just validate that the resulting .so file does not contain any R_* relocation entries except R_*_NONE. Signed-off-by: Fangrui Song Signed-off-by: Thomas Gleixner Tested-by: Vincenzo Frascino # for aarch64 Reviewed-by: Christophe Leroy Reviewed-by: Vincenzo Frascino # for vDSO, aarch64 Acked-by: Michael Ellerman (powerpc) Link: https://lore.kernel.org/r/20230310190750.3323802-1-maskray@google.com --- arch/arm/vdso/Makefile | 4 +--- arch/arm64/kernel/vdso/Makefile | 4 +--- arch/arm64/kernel/vdso32/Makefile | 3 --- arch/csky/kernel/vdso/Makefile | 4 +--- arch/loongarch/vdso/Makefile | 4 +--- arch/mips/vdso/Makefile | 4 +--- arch/powerpc/kernel/vdso/Makefile | 2 +- arch/riscv/kernel/vdso/Makefile | 4 +--- arch/s390/kernel/vdso32/Makefile | 3 +-- arch/s390/kernel/vdso64/Makefile | 3 +-- arch/x86/entry/vdso/Makefile | 5 +---- lib/vdso/Makefile | 13 ++++--------- 12 files changed, 14 insertions(+), 39 deletions(-) diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index a7ec06ce3785..515ca33b854c 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -1,8 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile hostprogs := vdsomunge diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index beaf9586338f..fe7a53c6781f 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -6,9 +6,7 @@ # Heavily based on the vDSO Makefiles for other archs. # -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64 +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso := vgettimeofday.o note.o sigreturn.o diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index f59bd1a4ead6..d014162c5c71 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -3,9 +3,6 @@ # Makefile for vdso32 # -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 include $(srctree)/lib/vdso/Makefile # Same as cc-*option, but using CC_COMPAT instead of CC diff --git a/arch/csky/kernel/vdso/Makefile b/arch/csky/kernel/vdso/Makefile index 0b6909f10667..299e4e41ebc5 100644 --- a/arch/csky/kernel/vdso/Makefile +++ b/arch/csky/kernel/vdso/Makefile @@ -1,8 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_CKCORE_ADDR32|R_CKCORE_JUMP_SLOT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile # Symbols present in the vdso diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile index d89e2ac75f7b..461240ab4436 100644 --- a/arch/loongarch/vdso/Makefile +++ b/arch/loongarch/vdso/Makefile @@ -1,9 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 # Objects to go into the VDSO. -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_LARCH_32|R_LARCH_64|R_LARCH_MARK_LA|R_LARCH_JUMP_SLOT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o sigreturn.o diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile index 18af9474ed0e..eb56581f6d73 100644 --- a/arch/mips/vdso/Makefile +++ b/arch/mips/vdso/Makefile @@ -4,9 +4,7 @@ # Sanitizer runtimes are unavailable and cannot be linked here. KCSAN_SANITIZE := n -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso-y := elf.o vgettimeofday.o sigreturn.o diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile index 66f723f53be2..4c3f34485f08 100644 --- a/arch/powerpc/kernel/vdso/Makefile +++ b/arch/powerpc/kernel/vdso/Makefile @@ -2,7 +2,7 @@ # List of files in the vdso, has to be asm only for now -ARCH_REL_TYPE_ABS := R_PPC_JUMP_SLOT|R_PPC_GLOB_DAT|R_PPC_ADDR32|R_PPC_ADDR24|R_PPC_ADDR16|R_PPC_ADDR16_LO|R_PPC_ADDR16_HI|R_PPC_ADDR16_HA|R_PPC_ADDR14|R_PPC_ADDR14_BRTAKEN|R_PPC_ADDR14_BRNTAKEN|R_PPC_REL24 +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile index 06e6b27f3bcc..a04b3bc35ca2 100644 --- a/arch/riscv/kernel/vdso/Makefile +++ b/arch/riscv/kernel/vdso/Makefile @@ -1,9 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only # Copied from arch/tile/kernel/vdso/Makefile -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_RISCV_32|R_RISCV_64|R_RISCV_JUMP_SLOT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile # Symbols present in the vdso vdso-syms = rt_sigreturn diff --git a/arch/s390/kernel/vdso32/Makefile b/arch/s390/kernel/vdso32/Makefile index 245bddfe9bc0..bafd3147eb4e 100644 --- a/arch/s390/kernel/vdso32/Makefile +++ b/arch/s390/kernel/vdso32/Makefile @@ -2,9 +2,8 @@ # List of files in the vdso KCOV_INSTRUMENT := n -ARCH_REL_TYPE_ABS := R_390_COPY|R_390_GLOB_DAT|R_390_JMP_SLOT|R_390_RELATIVE -ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso32 = vdso_user_wrapper-32.o note-32.o diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile index 34f9542636e9..a766d286e15f 100644 --- a/arch/s390/kernel/vdso64/Makefile +++ b/arch/s390/kernel/vdso64/Makefile @@ -2,9 +2,8 @@ # List of files in the vdso KCOV_INSTRUMENT := n -ARCH_REL_TYPE_ABS := R_390_COPY|R_390_GLOB_DAT|R_390_JMP_SLOT|R_390_RELATIVE -ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile obj-vdso64 = vdso_user_wrapper.o note.o obj-cvdso64 = vdso64_generic.o getcpu.o diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 1506a22a4fb6..6a1821bd7d5e 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -3,10 +3,7 @@ # Building vDSO images for x86. # -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before -# the inclusion of generic Makefile. -ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE| -ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE +# Include the generic Makefile to check the built vdso. include $(srctree)/lib/vdso/Makefile # Sanitizer runtimes are unavailable and cannot be linked here. diff --git a/lib/vdso/Makefile b/lib/vdso/Makefile index e814061d6aa0..9f031eafc465 100644 --- a/lib/vdso/Makefile +++ b/lib/vdso/Makefile @@ -5,18 +5,13 @@ GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH)) c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c) -# This cmd checks that the vdso library does not contain absolute relocation +# This cmd checks that the vdso library does not contain dynamic relocations. # It has to be called after the linking of the vdso library and requires it # as a parameter. # -# $(ARCH_REL_TYPE_ABS) is defined in the arch specific makefile and corresponds -# to the absolute relocation types printed by "objdump -R" and accepted by the -# dynamic linker. -ifndef ARCH_REL_TYPE_ABS -$(error ARCH_REL_TYPE_ABS is not set) -endif - +# As a workaround for some GNU ld ports which produce unneeded R_*_NONE +# dynamic relocations, ignore R_*_NONE. quiet_cmd_vdso_check = VDSOCHK $@ - cmd_vdso_check = if $(OBJDUMP) -R $@ | grep -E -h "$(ARCH_REL_TYPE_ABS)"; \ + cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q " R_\w*_"; \ then (echo >&2 "$@: dynamic relocations are not supported"; \ rm -f $@; /bin/false); fi