shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-06 19:08:57 +09:00
Code Issues Packages Projects Releases Wiki Activity

FROMLIST: ubsan: Add trap instrumentation option

Browse Source 
The Undefined Behavior Sanitizer can operate in two modes: warning
reporting mode via lib/ubsan.c handler calls, or trap mode, which uses
__builtin_trap() as the handler. Using lib/ubsan.c means the kernel
image is about 5% larger (due to all the debugging text and reporting
structures to capture details about the warning conditions). Using the
trap mode, the image size changes are much smaller, though at the loss
of the "warning only" mode.

In order to give greater flexibility to system builders that want
minimal changes to image size and are prepared to deal with kernel
threads being killed, this introduces CONFIG_UBSAN_TRAP. The resulting
image sizes comparison:

   text    data     bss       dec       hex     filename
19533663   6183037  18554956  44271656  2a38828 vmlinux.stock
19991849   7618513  18874448  46484810  2c54d4a vmlinux.ubsan
19712181   6284181  18366540  44362902  2a4ec96 vmlinux.ubsan-trap

CONFIG_UBSAN=y:      image +4.8% (text +2.3%, data +18.9%)
CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%)

Bug: 136249967
Link: https://lore.kernel.org/kernel-hardening/20191121181519.28637-2-keescook@chromium.org/
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Petrova <lenaptr@google.com>
Change-Id: Ifa36d25f9649958cfc7b78e21777390f128db165
This commit is contained in:
Kees Cook
2019-11-19 17:06:34 -08:00
committed by Todd Kjos
parent 9b177a7d1c
commit 44a3813052
3 changed files with 22 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Kconfig.ubsan
View File

@@ -5,12 +5,23 @@ config ARCH_HAS_UBSAN_SANITIZE_ALL
config UBSAN
bool "Undefined behaviour sanity checker"
help
This option enables undefined behaviour sanity checker
This option enables undefined behaviour sanity checker.
Compile-time instrumentation is used to detect various undefined
behaviours in runtime. Various types of checks may be enabled
behaviours at runtime. Various types of checks may be enabled
via boot parameter ubsan_handle
(see: Documentation/dev-tools/ubsan.rst).
config UBSAN_TRAP
bool "On Sanitizer warnings, stop the offending kernel thread"
depends on UBSAN
depends on $(cc-option, -fsanitize-undefined-trap-on-error)
help
Building kernels with Sanitizer features enabled tends to grow
the kernel size by over 5%, due to adding all the debugging
text on failure paths. To avoid this, Sanitizer instrumentation
can just issue a trap. This reduces the kernel size overhead but
turns all warnings into full thread-killing exceptions.
config UBSAN_SANITIZE_ALL
bool "Enable instrumentation for the entire kernel"
depends on UBSAN

2
lib/Makefile
View File

@@ -275,7 +275,9 @@ quiet_cmd_build_OID_registry = GEN $@
clean-files += oid_registry_data.c
obj-$(CONFIG_UCS2_STRING) += ucs2_string.o
ifneq ($(CONFIG_UBSAN_TRAP),y)
obj-$(CONFIG_UBSAN) += ubsan.o
endif
UBSAN_SANITIZE_ubsan.o := n
KASAN_SANITIZE_ubsan.o := n

9
scripts/Makefile.ubsan
View File

@@ -1,5 +1,10 @@
# SPDX-License-Identifier: GPL-2.0
ifdef CONFIG_UBSAN
ifdef CONFIG_UBSAN_ALIGNMENT
CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
endif
CFLAGS_UBSAN += $(call cc-option, -fsanitize=shift)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=integer-divide-by-zero)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=unreachable)
@@ -9,8 +14,8 @@ ifdef CONFIG_UBSAN
CFLAGS_UBSAN += $(call cc-option, -fsanitize=bool)
CFLAGS_UBSAN += $(call cc-option, -fsanitize=enum)
ifdef CONFIG_UBSAN_ALIGNMENT
CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
ifdef CONFIG_UBSAN_TRAP
CFLAGS_UBSAN += $(call cc-option, -fsanitize-undefined-trap-on-error)
endif
# -fsanitize=* options makes GCC less smart than usual and