--- /dev/null
+From 0d362be5b14200b77ecc2127936a5ff82fbffe41 Mon Sep 17 00:00:00 2001
+From: Nick Desaulniers <ndesaulniers@google.com>
+Date: Wed, 10 Aug 2022 15:24:40 -0700
+Subject: Makefile: link with -z noexecstack --no-warn-rwx-segments
+
+From: Nick Desaulniers <ndesaulniers@google.com>
+
+commit 0d362be5b14200b77ecc2127936a5ff82fbffe41 upstream.
+
+Users of GNU ld (BFD) from binutils 2.39+ will observe multiple
+instances of a new warning when linking kernels in the form:
+
+ ld: warning: vmlinux: missing .note.GNU-stack section implies executable stack
+ ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
+ ld: warning: vmlinux has a LOAD segment with RWX permissions
+
+Generally, we would like to avoid the stack being executable. Because
+there could be a need for the stack to be executable, assembler sources
+have to opt-in to this security feature via explicit creation of the
+.note.GNU-stack feature (which compilers create by default) or command
+line flag --noexecstack. Or we can simply tell the linker the
+production of such sections is irrelevant and to link the stack as
+--noexecstack.
+
+LLVM's LLD linker defaults to -z noexecstack, so this flag isn't
+strictly necessary when linking with LLD, only BFD, but it doesn't hurt
+to be explicit here for all linkers IMO. --no-warn-rwx-segments is
+currently BFD specific and only available in the current latest release,
+so it's wrapped in an ld-option check.
+
+While the kernel makes extensive usage of ELF sections, it doesn't use
+permissions from ELF segments.
+
+Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@kernel.dk/
+Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107
+Link: https://github.com/llvm/llvm-project/issues/57009
+Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
+Suggested-by: Fangrui Song <maskray@google.com>
+Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ Makefile | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+--- a/Makefile
++++ b/Makefile
+@@ -873,6 +873,11 @@ ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATI
+ LDFLAGS_vmlinux += $(call ld-option, --gc-sections,)
+ endif
+
++LDFLAGS += -z noexecstack
++ifeq ($(CONFIG_LD_IS_BFD),y)
++LDFLAGS += $(call ld-option,--no-warn-rwx-segments)
++endif
++
+ ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
+ LDFLAGS_vmlinux += $(call ld-option, -X,)
+ endif
--- /dev/null
+From ffcf9c5700e49c0aee42dcba9a12ba21338e8136 Mon Sep 17 00:00:00 2001
+From: Nick Desaulniers <ndesaulniers@google.com>
+Date: Wed, 10 Aug 2022 15:24:41 -0700
+Subject: x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments
+
+From: Nick Desaulniers <ndesaulniers@google.com>
+
+commit ffcf9c5700e49c0aee42dcba9a12ba21338e8136 upstream.
+
+Users of GNU ld (BFD) from binutils 2.39+ will observe multiple
+instances of a new warning when linking kernels in the form:
+
+ ld: warning: arch/x86/boot/pmjump.o: missing .note.GNU-stack section implies executable stack
+ ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker
+ ld: warning: arch/x86/boot/compressed/vmlinux has a LOAD segment with RWX permissions
+
+Generally, we would like to avoid the stack being executable. Because
+there could be a need for the stack to be executable, assembler sources
+have to opt-in to this security feature via explicit creation of the
+.note.GNU-stack feature (which compilers create by default) or command
+line flag --noexecstack. Or we can simply tell the linker the
+production of such sections is irrelevant and to link the stack as
+--noexecstack.
+
+LLVM's LLD linker defaults to -z noexecstack, so this flag isn't
+strictly necessary when linking with LLD, only BFD, but it doesn't hurt
+to be explicit here for all linkers IMO. --no-warn-rwx-segments is
+currently BFD specific and only available in the current latest release,
+so it's wrapped in an ld-option check.
+
+While the kernel makes extensive usage of ELF sections, it doesn't use
+permissions from ELF segments.
+
+Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@kernel.dk/
+Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107
+Link: https://github.com/llvm/llvm-project/issues/57009
+Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
+Suggested-by: Fangrui Song <maskray@google.com>
+Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/boot/Makefile | 2 +-
+ arch/x86/boot/compressed/Makefile | 6 ++++++
+ arch/x86/entry/vdso/Makefile | 2 +-
+ 3 files changed, 8 insertions(+), 2 deletions(-)
+
+--- a/arch/x86/boot/Makefile
++++ b/arch/x86/boot/Makefile
+@@ -100,7 +100,7 @@ $(obj)/zoffset.h: $(obj)/compressed/vmli
+ AFLAGS_header.o += -I$(objtree)/$(obj)
+ $(obj)/header.o: $(obj)/zoffset.h
+
+-LDFLAGS_setup.elf := -m elf_i386 -T
++LDFLAGS_setup.elf := -m elf_i386 -z noexecstack -T
+ $(obj)/setup.elf: $(src)/setup.ld $(SETUP_OBJS) FORCE
+ $(call if_changed,ld)
+
+--- a/arch/x86/boot/compressed/Makefile
++++ b/arch/x86/boot/compressed/Makefile
+@@ -55,6 +55,12 @@ else
+ LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \
+ && echo "-z noreloc-overflow -pie --no-dynamic-linker")
+ endif
++
++LDFLAGS += -z noexecstack
++ifeq ($(CONFIG_LD_IS_BFD),y)
++LDFLAGS += $(call ld-option,--no-warn-rwx-segments)
++endif
++
+ LDFLAGS_vmlinux := -T
+
+ hostprogs-y := mkpiggy
+--- a/arch/x86/entry/vdso/Makefile
++++ b/arch/x86/entry/vdso/Makefile
+@@ -183,7 +183,7 @@ quiet_cmd_vdso = VDSO $@
+
+ VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
+ $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
+- -Bsymbolic
++ -Bsymbolic -z noexecstack
+ GCOV_PROFILE := n
+
+ #
projects / thirdparty / kernel / stable-queue.git / commitdiff
