| Message ID | 20240714170847.2029108-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fortify: fix warnings in fortify tests with KASAN | expand |
On Mon, Jul 15, 2024 at 2:09 AM Masahiro Yamada <masahiroy@kernel.org> wrote: > > When a software KASAN mode is enabled, the fortify tests emit warnings > on some architectures. > > For example, for ARCH=arm, the combination of CONFIG_FORTIFY_SOURCE=y > and CONFIG_KASAN=y produces the following warnings: > > TEST lib/test_fortify/read_overflow-memchr.log > warning: unsafe memchr() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memchr.c > TEST lib/test_fortify/read_overflow-memchr_inv.log > warning: unsafe memchr_inv() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memchr_inv.c > TEST lib/test_fortify/read_overflow-memcmp.log > warning: unsafe memcmp() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memcmp.c > TEST lib/test_fortify/read_overflow-memscan.log > warning: unsafe memscan() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memscan.c > TEST lib/test_fortify/read_overflow2-memcmp.log > warning: unsafe memcmp() usage lacked '__read_overflow2' warning in lib/test_fortify/read_overflow2-memcmp.c > [ more and more similar warnings... ] > > Commit 9c2d1328f88a ("kbuild: provide reasonable defaults for tool > coverage") removed KASAN flags from non-kernel objects by default. > It was an intended behavior because lib/test_fortify/*.c are unit > tests that are not linked to the kernel. > > As it turns out, some architectures require -fsanitize=kernel-(hw)address > to define __SANITIZE_ADDRESS__ for the fortify tests. > > Without __SANITIZE_ADDRESS__ defined, arch/arm/include/asm/string.h > defines __NO_FORTIFY, thus excluding <linux/fortify-string.h>. > > This issue does not occur on x86 thanks to commit 4ec4190be4cf > ("kasan, x86: don't rename memintrinsics in uninstrumented files"), > but there are still some architectures that define __NO_FORTIFY > in such a situation. > > Set KASAN_SANITIZE=y explicitly to the fortify tests. > > Fixes: 9c2d1328f88a ("kbuild: provide reasonable defaults for tool coverage") > Reported-by: Arnd Bergmann <arnd@arndb.de> > Closes: https://lore.kernel.org/all/0e8dee26-41cc-41ae-9493-10cd1a8e3268@app.fastmail.com/ > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- Applied to linux-kbuild.
On July 14, 2024 10:04:32 AM PDT, Masahiro Yamada <masahiroy@kernel.org> wrote: >When a software KASAN mode is enabled, the fortify tests emit warnings >on some architectures. > >For example, for ARCH=arm, the combination of CONFIG_FORTIFY_SOURCE=y >and CONFIG_KASAN=y produces the following warnings: > > TEST lib/test_fortify/read_overflow-memchr.log > warning: unsafe memchr() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memchr.c > TEST lib/test_fortify/read_overflow-memchr_inv.log > warning: unsafe memchr_inv() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memchr_inv.c > TEST lib/test_fortify/read_overflow-memcmp.log > warning: unsafe memcmp() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memcmp.c > TEST lib/test_fortify/read_overflow-memscan.log > warning: unsafe memscan() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memscan.c > TEST lib/test_fortify/read_overflow2-memcmp.log > warning: unsafe memcmp() usage lacked '__read_overflow2' warning in lib/test_fortify/read_overflow2-memcmp.c > [ more and more similar warnings... ] > >Commit 9c2d1328f88a ("kbuild: provide reasonable defaults for tool >coverage") removed KASAN flags from non-kernel objects by default. >It was an intended behavior because lib/test_fortify/*.c are unit >tests that are not linked to the kernel. > >As it turns out, some architectures require -fsanitize=kernel-(hw)address >to define __SANITIZE_ADDRESS__ for the fortify tests. > >Without __SANITIZE_ADDRESS__ defined, arch/arm/include/asm/string.h >defines __NO_FORTIFY, thus excluding <linux/fortify-string.h>. > >This issue does not occur on x86 thanks to commit 4ec4190be4cf >("kasan, x86: don't rename memintrinsics in uninstrumented files"), >but there are still some architectures that define __NO_FORTIFY >in such a situation. > >Set KASAN_SANITIZE=y explicitly to the fortify tests. > >Fixes: 9c2d1328f88a ("kbuild: provide reasonable defaults for tool coverage") >Reported-by: Arnd Bergmann <arnd@arndb.de> >Closes: https://lore.kernel.org/all/0e8dee26-41cc-41ae-9493-10cd1a8e3268@app.fastmail.com/ >Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> >--- > >Kees Cook said "I'll try to figure this out", but I have not seen a patch so far, >so I decided to do this myself. >(https://lore.kernel.org/all/202405310908.A5733DF@keescook/) > >I will send a pull req with this and some other fixes. >I need to fix this, as v6.10 will be released soon. Awesome! Thanks for figuring this out; I hadn't had time yet. Acked-by: Kees Cook<kees@kernel.org>
diff --git a/lib/Makefile b/lib/Makefile index 3b1769045651..30337431d10e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -426,3 +426,7 @@ $(obj)/$(TEST_FORTIFY_LOG): $(addprefix $(obj)/, $(TEST_FORTIFY_LOGS)) FORCE ifeq ($(CONFIG_FORTIFY_SOURCE),y) $(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG) endif + +# Some architectures define __NO_FORTIFY if __SANITIZE_ADDRESS__ is undefined. +# Pass CFLAGS_KASAN to avoid warnings. +$(foreach x, $(patsubst %.log,%.o,$(TEST_FORTIFY_LOGS)), $(eval KASAN_SANITIZE_$(x) := y))
When a software KASAN mode is enabled, the fortify tests emit warnings on some architectures. For example, for ARCH=arm, the combination of CONFIG_FORTIFY_SOURCE=y and CONFIG_KASAN=y produces the following warnings: TEST lib/test_fortify/read_overflow-memchr.log warning: unsafe memchr() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memchr.c TEST lib/test_fortify/read_overflow-memchr_inv.log warning: unsafe memchr_inv() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memchr_inv.c TEST lib/test_fortify/read_overflow-memcmp.log warning: unsafe memcmp() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memcmp.c TEST lib/test_fortify/read_overflow-memscan.log warning: unsafe memscan() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memscan.c TEST lib/test_fortify/read_overflow2-memcmp.log warning: unsafe memcmp() usage lacked '__read_overflow2' warning in lib/test_fortify/read_overflow2-memcmp.c [ more and more similar warnings... ] Commit 9c2d1328f88a ("kbuild: provide reasonable defaults for tool coverage") removed KASAN flags from non-kernel objects by default. It was an intended behavior because lib/test_fortify/*.c are unit tests that are not linked to the kernel. As it turns out, some architectures require -fsanitize=kernel-(hw)address to define __SANITIZE_ADDRESS__ for the fortify tests. Without __SANITIZE_ADDRESS__ defined, arch/arm/include/asm/string.h defines __NO_FORTIFY, thus excluding <linux/fortify-string.h>. This issue does not occur on x86 thanks to commit 4ec4190be4cf ("kasan, x86: don't rename memintrinsics in uninstrumented files"), but there are still some architectures that define __NO_FORTIFY in such a situation. Set KASAN_SANITIZE=y explicitly to the fortify tests. Fixes: 9c2d1328f88a ("kbuild: provide reasonable defaults for tool coverage") Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/all/0e8dee26-41cc-41ae-9493-10cd1a8e3268@app.fastmail.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Kees Cook said "I'll try to figure this out", but I have not seen a patch so far, so I decided to do this myself. (https://lore.kernel.org/all/202405310908.A5733DF@keescook/) I will send a pull req with this and some other fixes. I need to fix this, as v6.10 will be released soon. lib/Makefile | 4 ++++ 1 file changed, 4 insertions(+)