From: Dmitry Antipov <dmantipov@yandex.ru> mainline inclusion from mainline-v6.7-rc4 commit 4e86f32a13af1970d21be94f659cae56bbe487ee category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9HK6L CVE: CVE-2024-26907 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Recently the kernel test robot has reported an ARM-specific BUILD_BUG_ON() in an old and unmaintained wil6210 wireless driver. The problem comes from the structure packing rules of old ARM ABI ('-mabi=apcs-gnu'). For example, the following structure is packed to 18 bytes instead of 16: struct poorly_packed { unsigned int a; unsigned int b; unsigned short c; union { struct { unsigned short d; unsigned int e; } __attribute__((packed)); struct { unsigned short d; unsigned int e; } __attribute__((packed)) inner; }; } __attribute__((packed)); To fit it into 16 bytes, it's required to add packed attribute to the container union as well: struct poorly_packed { unsigned int a; unsigned int b; unsigned short c; union { struct { unsigned short d; unsigned int e; } __attribute__((packed)); struct { unsigned short d; unsigned int e; } __attribute__((packed)) inner; } __attribute__((packed)); } __attribute__((packed)); Thanks to Andrew Pinski of GCC team for sorting the things out at https://gcc.gnu.org/pipermail/gcc/2023-November/242888.html. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202311150821.cI4yciFE-lkp@intel.com Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Link: https://lore.kernel.org/r/20231120110607.98956-1-dmantipov@yandex.ru Fixes: 50d7bd38c3aa ("stddef: Introduce struct_group() helper macro") Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> --- include/uapi/linux/stddef.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/stddef.h b/include/uapi/linux/stddef.h index 46c7bab501cb..20f5e61617ac 100644 --- a/include/uapi/linux/stddef.h +++ b/include/uapi/linux/stddef.h @@ -27,7 +27,7 @@ union { \ struct { MEMBERS } ATTRS; \ struct TAG { MEMBERS } ATTRS NAME; \ - } + } ATTRS #ifdef __cplusplus /* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */ -- 2.25.1