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objtool: Add CONFIG_OBJTOOL 

Now that stack validation is an optional feature of objtool, add
CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with
it.

CONFIG_STACK_VALIDATION can now be considered to be frame-pointer
specific.  CONFIG_UNWINDER_ORC is already inherently valid for live
patching, so no need to "validate" it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com
This commit is contained in:
Josh Poimboeuf 2022-04-18 09:50:36 -07:00 committed by Peter Zijlstra
parent c2bdd61c98
commit 03f16cd020
17 changed files with 73 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile
View File

@ -1302,7 +1302,7 @@ install: sub_make_done :=
# ---------------------------------------------------------------------------
# Tools
ifdef CONFIG_STACK_VALIDATION
ifdef CONFIG_OBJTOOL
prepare: tools/objtool
endif

8
arch/Kconfig
View File

@ -1028,11 +1028,14 @@ config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
depends on MMU
select ARCH_HAS_ELF_RANDOMIZE
config HAVE_OBJTOOL
bool
config HAVE_STACK_VALIDATION
bool
help
Architecture supports the 'objtool check' host tool command, which
performs compile-time stack metadata validation.
Architecture supports objtool compile-time frame pointer rule
validation.
config HAVE_RELIABLE_STACKTRACE
bool
@ -1302,6 +1305,7 @@ config HAVE_STATIC_CALL
config HAVE_STATIC_CALL_INLINE
bool
depends on HAVE_STATIC_CALL
select OBJTOOL
config HAVE_PREEMPT_DYNAMIC
bool

18
arch/x86/Kconfig
View File

@ -188,7 +188,7 @@ config X86
select HAVE_CONTEXT_TRACKING if X86_64
select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
select HAVE_C_RECORDMCOUNT
select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION
select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL
select HAVE_BUILDTIME_MCOUNT_SORT
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS
@ -231,6 +231,7 @@ config X86
select HAVE_MOVE_PMD
select HAVE_MOVE_PUD
select HAVE_NMI
select HAVE_OBJTOOL if X86_64
select HAVE_OPTPROBES
select HAVE_PCSPKR_PLATFORM
select HAVE_PERF_EVENTS
@ -239,17 +240,17 @@ config X86
select HAVE_PCI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
select HAVE_POSIX_CPU_TIMERS_TASK_WORK
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC || STACK_VALIDATION
select HAVE_FUNCTION_ARG_ACCESS_API
select HAVE_SETUP_PER_CPU_AREA
select HAVE_SOFTIRQ_ON_OWN_STACK
select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
select HAVE_STACK_VALIDATION if X86_64
select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
select HAVE_STATIC_CALL
select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL
select HAVE_PREEMPT_DYNAMIC_CALL
select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
@ -268,7 +269,6 @@ config X86
select RTC_MC146818_LIB
select SPARSE_IRQ
select SRCU
select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select TRACE_IRQFLAGS_SUPPORT
@ -459,6 +459,7 @@ config GOLDFISH
config RETPOLINE
bool "Avoid speculative indirect branches in kernel"
select OBJTOOL if HAVE_OBJTOOL
default y
help
Compile kernel with the retpoline compiler options to guard against
@ -472,6 +473,7 @@ config CC_HAS_SLS
config SLS
bool "Mitigate Straight-Line-Speculation"
depends on CC_HAS_SLS && X86_64
select OBJTOOL if HAVE_OBJTOOL
default n
help
Compile the kernel with straight-line-speculation options to guard
@ -1819,6 +1821,7 @@ config ARCH_RANDOM
config X86_SMAP
def_bool y
prompt "Supervisor Mode Access Prevention" if EXPERT
select OBJTOOL if HAVE_OBJTOOL
help
Supervisor Mode Access Prevention (SMAP) is a security
feature in newer Intel processors. There is a small
@ -1855,9 +1858,10 @@ config CC_HAS_IBT
config X86_KERNEL_IBT
prompt "Indirect Branch Tracking"
bool
depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION
depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
depends on !LD_IS_LLD || LLD_VERSION >= 140000
select OBJTOOL
help
Build the kernel with support for Indirect Branch Tracking, a
hardware support course-grain forward-edge Control Flow Integrity

2
arch/x86/Kconfig.debug
View File

@ -237,7 +237,7 @@ choice
config UNWINDER_ORC
bool "ORC unwinder"
depends on X86_64
select STACK_VALIDATION
select OBJTOOL
help
This option enables the ORC (Oops Rewind Capability) unwinder for
unwinding kernel stack traces. It uses a custom data format which is

6
arch/x86/include/asm/jump_label.h
View File

@ -20,7 +20,7 @@
_ASM_PTR "%c0 + %c1 - .\n\t" \
".popsection \n\t"
#ifdef CONFIG_STACK_VALIDATION
#ifdef CONFIG_OBJTOOL
static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
{
@ -34,7 +34,7 @@ l_yes:
return true;
}
#else
#else /* !CONFIG_OBJTOOL */
static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
{
@ -48,7 +48,7 @@ l_yes:
return true;
}
#endif /* STACK_VALIDATION */
#endif /* CONFIG_OBJTOOL */
static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
{

6
arch/x86/kernel/alternative.c
View File

@ -338,7 +338,7 @@ next:
}
}
#if defined(CONFIG_RETPOLINE) && defined(CONFIG_STACK_VALIDATION)
#if defined(CONFIG_RETPOLINE) && defined(CONFIG_OBJTOOL)
/*
* CALL/JMP *%\reg
@ -507,11 +507,11 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
}
}
#else /* !RETPOLINES || !CONFIG_STACK_VALIDATION */
#else /* !CONFIG_RETPOLINE || !CONFIG_OBJTOOL */
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
#endif /* CONFIG_RETPOLINE && CONFIG_STACK_VALIDATION */
#endif /* CONFIG_RETPOLINE && CONFIG_OBJTOOL */
#ifdef CONFIG_X86_KERNEL_IBT

6
include/linux/compiler.h
View File

@ -109,7 +109,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#endif
/* Unreachable code */
#ifdef CONFIG_STACK_VALIDATION
#ifdef CONFIG_OBJTOOL
/*
* These macros help objtool understand GCC code flow for unreachable code.
* The __COUNTER__ based labels are a hack to make each instance of the macros
@ -128,10 +128,10 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
/* Annotate a C jump table to allow objtool to follow the code flow */
#define __annotate_jump_table __section(".rodata..c_jump_table")
#else
#else /* !CONFIG_OBJTOOL */
#define annotate_unreachable()
#define __annotate_jump_table
#endif
#endif /* CONFIG_OBJTOOL */
#ifndef unreachable
# define unreachable() do { \

6
include/linux/instrumentation.h
View File

@ -2,7 +2,7 @@
#ifndef __LINUX_INSTRUMENTATION_H
#define __LINUX_INSTRUMENTATION_H
#if defined(CONFIG_DEBUG_ENTRY) && defined(CONFIG_STACK_VALIDATION)
#ifdef CONFIG_VMLINUX_VALIDATION
#include <linux/stringify.h>
@ -53,9 +53,9 @@
".popsection\n\t" : : "i" (c)); \
})
#define instrumentation_end() __instrumentation_end(__COUNTER__)
#else
#else /* !CONFIG_VMLINUX_VALIDATION */
# define instrumentation_begin() do { } while(0)
# define instrumentation_end() do { } while(0)
#endif
#endif /* CONFIG_VMLINUX_VALIDATION */
#endif /* __LINUX_INSTRUMENTATION_H */

6
include/linux/objtool.h
View File

@ -38,7 +38,7 @@ struct unwind_hint {
#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
#define UNWIND_HINT_TYPE_FUNC 3
#ifdef CONFIG_STACK_VALIDATION
#ifdef CONFIG_OBJTOOL
#ifndef __ASSEMBLY__
@ -157,7 +157,7 @@ struct unwind_hint {
#endif /* __ASSEMBLY__ */
#else /* !CONFIG_STACK_VALIDATION */
#else /* !CONFIG_OBJTOOL */
#ifndef __ASSEMBLY__
@ -179,6 +179,6 @@ struct unwind_hint {
.endm
#endif
#endif /* CONFIG_STACK_VALIDATION */
#endif /* CONFIG_OBJTOOL */
#endif /* _LINUX_OBJTOOL_H */

1
kernel/trace/Kconfig
View File

@ -728,6 +728,7 @@ config FTRACE_MCOUNT_USE_OBJTOOL
depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
depends on !FTRACE_MCOUNT_USE_CC
depends on FTRACE_MCOUNT_RECORD
select OBJTOOL
config FTRACE_MCOUNT_USE_RECORDMCOUNT
def_bool y

20
lib/Kconfig.debug
View File

@ -485,24 +485,25 @@ config FRAME_POINTER
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
config OBJTOOL
bool
config STACK_VALIDATION
bool "Compile-time stack metadata validation"
depends on HAVE_STACK_VALIDATION
depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
select OBJTOOL
default n
help
Add compile-time checks to validate stack metadata, including frame
pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
that runtime stack traces are more reliable.
This is also a prerequisite for generation of ORC unwind data, which
is needed for CONFIG_UNWINDER_ORC.
Validate frame pointer rules at compile-time. This helps ensure that
runtime stack traces are more reliable.
For more information, see
tools/objtool/Documentation/stack-validation.txt.
config VMLINUX_VALIDATION
bool
depends on STACK_VALIDATION && DEBUG_ENTRY
depends on HAVE_OBJTOOL && DEBUG_ENTRY
select OBJTOOL
default y
config VMLINUX_MAP
@ -2035,10 +2036,11 @@ config KCOV
bool "Code coverage for fuzzing"
depends on ARCH_HAS_KCOV
depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
depends on !ARCH_WANTS_NO_INSTR || HAVE_OBJTOOL || \
GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
select DEBUG_FS
select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
select OBJTOOL if HAVE_OBJTOOL
help
KCOV exposes kernel code coverage information in a form suitable
for coverage-guided fuzzing (randomized testing).

3
lib/Kconfig.kcsan
View File

@ -187,7 +187,8 @@ config KCSAN_WEAK_MEMORY
# We can either let objtool nop __tsan_func_{entry,exit}() and builtin
# atomics instrumentation in .noinstr.text, or use a compiler that can
# implement __no_kcsan to really remove all instrumentation.
depends on STACK_VALIDATION || CC_IS_GCC || CLANG_VERSION >= 140000
depends on HAVE_OBJTOOL || CC_IS_GCC || CLANG_VERSION >= 140000
select OBJTOOL if HAVE_OBJTOOL
help
Enable support for modeling a subset of weak memory, which allows
detecting a subset of data races due to missing memory barriers.

2
lib/Kconfig.ubsan
View File

@ -94,7 +94,7 @@ config UBSAN_UNREACHABLE
bool "Perform checking for unreachable code"
# objtool already handles unreachable checking and gets angry about
# seeing UBSan instrumentation located in unreachable places.
depends on !STACK_VALIDATION
depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || X86_SMAP))
depends on $(cc-option,-fsanitize=unreachable)
help
This option enables -fsanitize=unreachable which checks for control

4
scripts/Makefile.build
View File

@ -222,7 +222,7 @@ cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),
$(sub_cmd_record_mcount))
endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
ifdef CONFIG_STACK_VALIDATION
ifdef CONFIG_OBJTOOL
objtool := $(objtree)/tools/objtool/objtool
@ -241,7 +241,7 @@ objtool_args = \
cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
endif # CONFIG_STACK_VALIDATION
endif # CONFIG_OBJTOOL
ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)

32
scripts/link-vmlinux.sh
View File

@ -108,8 +108,11 @@ objtool_link()
local objtoolcmd;
local objtoolopt;
if is_enabled CONFIG_STACK_VALIDATION && \
( is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ); then
if ! is_enabled CONFIG_OBJTOOL; then
return;
fi
if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
# Don't perform vmlinux validation unless explicitly requested,
# but run objtool on vmlinux.o now that we have an object file.
@ -126,10 +129,23 @@ objtool_link()
objtoolopt="${objtoolopt} --orc"
fi
if is_enabled CONFIG_RETPOLINE; then
objtoolopt="${objtoolopt} --retpoline"
fi
if is_enabled CONFIG_SLS; then
objtoolopt="${objtoolopt} --sls"
fi
if is_enabled CONFIG_STACK_VALIDATION; then
objtoolopt="${objtoolopt} --stackval"
fi
if is_enabled CONFIG_X86_SMAP; then
objtoolopt="${objtoolopt} --uaccess"
fi
objtoolopt="${objtoolopt} --lto"
fi
@ -139,18 +155,6 @@ objtool_link()
if [ -n "${objtoolopt}" ]; then
if is_enabled CONFIG_RETPOLINE; then
objtoolopt="${objtoolopt} --retpoline"
fi
if is_enabled CONFIG_SLS; then
objtoolopt="${objtoolopt} --sls"
fi
if is_enabled CONFIG_X86_SMAP; then
objtoolopt="${objtoolopt} --uaccess"
fi
if ! is_enabled CONFIG_FRAME_POINTER; then
objtoolopt="${objtoolopt} --no-fp"
fi

2
scripts/package/builddeb
View File

@ -67,7 +67,7 @@ deploy_kernel_headers () {
) > debian/hdrsrcfiles
{
if is_enabled CONFIG_STACK_VALIDATION; then
if is_enabled CONFIG_OBJTOOL; then
echo tools/objtool/objtool
fi

6
tools/include/linux/objtool.h
View File

@ -38,7 +38,7 @@ struct unwind_hint {
#define UNWIND_HINT_TYPE_REGS_PARTIAL 2
#define UNWIND_HINT_TYPE_FUNC 3
#ifdef CONFIG_STACK_VALIDATION
#ifdef CONFIG_OBJTOOL
#ifndef __ASSEMBLY__
@ -157,7 +157,7 @@ struct unwind_hint {
#endif /* __ASSEMBLY__ */
#else /* !CONFIG_STACK_VALIDATION */
#else /* !CONFIG_OBJTOOL */
#ifndef __ASSEMBLY__
@ -179,6 +179,6 @@ struct unwind_hint {
.endm
#endif
#endif /* CONFIG_STACK_VALIDATION */
#endif /* CONFIG_OBJTOOL */
#endif /* _LINUX_OBJTOOL_H */