c6d308534a
UBSAN uses compile-time instrumentation to catch undefined behavior (UB). Compiler inserts code that perform certain kinds of checks before operations that could cause UB. If check fails (i.e. UB detected) __ubsan_handle_* function called to print error message. So the most of the work is done by compiler. This patch just implements ubsan handlers printing errors. GCC has this capability since 4.9.x [1] (see -fsanitize=undefined option and its suboptions). However GCC 5.x has more checkers implemented [2]. Article [3] has a bit more details about UBSAN in the GCC. [1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html [2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html [3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/ Issues which UBSAN has found thus far are: Found bugs: * out-of-bounds access -97840cb67f("netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind") undefined shifts: *d48458d4a7("jbd2: use a better hash function for the revoke table") *10632008b9("clockevents: Prevent shift out of bounds") * 'x << -1' shift in ext4 - http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com> * undefined rol32(0) - http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com> * undefined dirty_ratelimit calculation - http://lkml.kernel.org/r/<566594E2.3050306@odin.com> * undefined roundown_pow_of_two(0) - http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com> * [WONTFIX] undefined shift in __bpf_prog_run - http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com> WONTFIX here because it should be fixed in bpf program, not in kernel. signed overflows: *32a8df4e0b("sched: Fix odd values in effective_load() calculations") * mul overflow in ntp - http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com> * incorrect conversion into rtc_time in rtc_time64_to_tm() - http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com> * unvalidated timespec in io_getevents() - http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com> * [NOTABUG] signed overflow in ktime_add_safe() - http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com> [akpm@linux-foundation.org: fix unused local warning] [akpm@linux-foundation.org: fix __int128 build woes] Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Marek <mmarek@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Yury Gribov <y.gribov@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
79 lines
3.2 KiB
Makefile
79 lines
3.2 KiB
Makefile
#
|
|
# The stub may be linked into the kernel proper or into a separate boot binary,
|
|
# but in either case, it executes before the kernel does (with MMU disabled) so
|
|
# things like ftrace and stack-protector are likely to cause trouble if left
|
|
# enabled, even if doing so doesn't break the build.
|
|
#
|
|
cflags-$(CONFIG_X86_32) := -march=i386
|
|
cflags-$(CONFIG_X86_64) := -mcmodel=small
|
|
cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 \
|
|
-fPIC -fno-strict-aliasing -mno-red-zone \
|
|
-mno-mmx -mno-sse
|
|
|
|
cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS))
|
|
cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \
|
|
-fno-builtin -fpic -mno-single-pic-base
|
|
|
|
cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
|
|
|
|
KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
|
|
$(call cc-option,-ffreestanding) \
|
|
$(call cc-option,-fno-stack-protector)
|
|
|
|
GCOV_PROFILE := n
|
|
KASAN_SANITIZE := n
|
|
UBSAN_SANITIZE := n
|
|
|
|
lib-y := efi-stub-helper.o
|
|
|
|
# include the stub's generic dependencies from lib/ when building for ARM/arm64
|
|
arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
|
|
|
|
$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
|
|
$(call if_changed_rule,cc_o_c)
|
|
|
|
lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
|
|
$(patsubst %.c,lib-%.o,$(arm-deps))
|
|
|
|
lib-$(CONFIG_ARM) += arm32-stub.o
|
|
lib-$(CONFIG_ARM64) += arm64-stub.o
|
|
CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
|
|
|
|
#
|
|
# arm64 puts the stub in the kernel proper, which will unnecessarily retain all
|
|
# code indefinitely unless it is annotated as __init/__initdata/__initconst etc.
|
|
# So let's apply the __init annotations at the section level, by prefixing
|
|
# the section names directly. This will ensure that even all the inline string
|
|
# literals are covered.
|
|
# The fact that the stub and the kernel proper are essentially the same binary
|
|
# also means that we need to be extra careful to make sure that the stub does
|
|
# not rely on any absolute symbol references, considering that the virtual
|
|
# kernel mapping that the linker uses is not active yet when the stub is
|
|
# executing. So build all C dependencies of the EFI stub into libstub, and do
|
|
# a verification pass to see if any absolute relocations exist in any of the
|
|
# object files.
|
|
#
|
|
extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
|
|
lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-y))
|
|
|
|
STUBCOPY_FLAGS-y := -R .debug* -R *ksymtab* -R *kcrctab*
|
|
STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
|
|
--prefix-symbols=__efistub_
|
|
STUBCOPY_RELOC-$(CONFIG_ARM64) := R_AARCH64_ABS
|
|
|
|
$(obj)/%.stub.o: $(obj)/%.o FORCE
|
|
$(call if_changed,stubcopy)
|
|
|
|
quiet_cmd_stubcopy = STUBCPY $@
|
|
cmd_stubcopy = if $(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@; then \
|
|
$(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y) \
|
|
&& (echo >&2 "$@: absolute symbol references not allowed in the EFI stub"; \
|
|
rm -f $@; /bin/false); else /bin/false; fi
|
|
|
|
#
|
|
# ARM discards the .data section because it disallows r/w data in the
|
|
# decompressor. So move our .data to .data.efistub, which is preserved
|
|
# explicitly by the decompressor linker script.
|
|
#
|
|
STUBCOPY_FLAGS-$(CONFIG_ARM) += --rename-section .data=.data.efistub
|
|
STUBCOPY_RELOC-$(CONFIG_ARM) := R_ARM_ABS
|