2024-02-23 17:08:39

by Kees Cook

Subject: [PATCH] init/Kconfig: Lower GCC version check for -Warray-bounds

We continue to see false positives from -Warray-bounds even in GCC 10,
which is getting reported in a few places[1] still:

security/security.c:811:2: warning: ‘memcpy’ offset 32 is out of the bounds [0, 0] [-Warray-bounds]

Lower the GCC version check from 11 to 10.

Reported-by: Lu Yao <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/linux-next/[email protected] [1]
Signed-off-by: Kees Cook <[email protected]>
---
Cc: Masahiro Yamada <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: Gustavo A. R. Silva <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Johannes Weiner <[email protected]>
---
init/Kconfig | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 8d4e836e1b6b..7b352f2943f2 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -867,14 +867,14 @@ config CC_IMPLICIT_FALLTHROUGH
default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5)
default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough)

-# Currently, disable gcc-11+ array-bounds globally.
+# Currently, disable gcc-10+ array-bounds globally.
# It's still broken in gcc-13, so no upper bound yet.
-config GCC11_NO_ARRAY_BOUNDS
+config GCC10_NO_ARRAY_BOUNDS
def_bool y

config CC_NO_ARRAY_BOUNDS
bool
- default y if CC_IS_GCC && GCC_VERSION >= 110000 && GCC11_NO_ARRAY_BOUNDS
+ default y if CC_IS_GCC && GCC_VERSION >= 100000 && GCC10_NO_ARRAY_BOUNDS

# Currently, disable -Wstringop-overflow for GCC 11, globally.
config GCC11_NO_STRINGOP_OVERFLOW
--
2.34.1

2024-02-23 19:11:44

by Paul Moore

Subject: Re: [PATCH] init/Kconfig: Lower GCC version check for -Warray-bounds

On Fri, Feb 23, 2024 at 12:08 PM Kees Cook <[email protected]> wrote:
>
> We continue to see false positives from -Warray-bounds even in GCC 10,
> which is getting reported in a few places[1] still:
>
> security/security.c:811:2: warning: ‘memcpy’ offset 32 is out of the bounds [0, 0] [-Warray-bounds]
>
> Lower the GCC version check from 11 to 10.
>
> Reported-by: Lu Yao <[email protected]>
> Closes: https://lore.kernel.org/lkml/[email protected]/
> Link: https://lore.kernel.org/linux-next/[email protected] [1]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> Cc: Masahiro Yamada <[email protected]>
> Cc: Paul Moore <[email protected]>
> Cc: Gustavo A. R. Silva <[email protected]>
> Cc: Nathan Chancellor <[email protected]>
> Cc: Christophe Leroy <[email protected]>
> Cc: Johannes Weiner <[email protected]>
> ---
> init/Kconfig | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)

Thanks Kees.

Reviewed-by: Paul Moore <[email protected]>

--
paul-moore.com