From: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@xxxxxxxxx> At present we have 2 different macros to calculate the size of a member of a struct: FIELD_SIZEOF() and sizeof_field(). As a prerequisite to bringing uniformity to the entire kernel source tree, add sizeof_member() macro as it is both more pleasant (not upper case) and more correct (sizeof()-family cannot operate on bit fields; this is meant to operate on struct members), as discussed[1]. Future patches will replace all occurrences of above macros with sizeof_member(). [1] https://www.openwall.com/lists/kernel-hardening/2019/07/02/2 Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@xxxxxxxxx> Link: https://lore.kernel.org/r/20190924105839.110713-2-pankaj.laxminarayan.bharadiya@xxxxxxxxx Co-developed-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- include/linux/stddef.h | 13 ++++++++++++- tools/testing/selftests/bpf/bpf_util.h | 6 +++--- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/include/linux/stddef.h b/include/linux/stddef.h index 998a4ba28eba..ecadb736c853 100644 --- a/include/linux/stddef.h +++ b/include/linux/stddef.h @@ -27,6 +27,17 @@ enum { */ #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) +/** + * sizeof_member(TYPE, MEMBER) - get the size of a struct's member + * + * @TYPE: the target struct + * @MEMBER: the target struct's member + * + * Return: the size of @MEMBER in the struct definition without having a + * declared instance of @TYPE. + */ +#define sizeof_member(TYPE, MEMBER) (sizeof(((TYPE *)0)->MEMBER)) + /** * offsetofend(TYPE, MEMBER) * @@ -34,6 +45,6 @@ enum { * @MEMBER: The member within the structure to get the end offset of */ #define offsetofend(TYPE, MEMBER) \ - (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER)) + (offsetof(TYPE, MEMBER) + sizeof_member(TYPE, MEMBER)) #endif diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h index ec219f84e041..6b4b3e24ba9f 100644 --- a/tools/testing/selftests/bpf/bpf_util.h +++ b/tools/testing/selftests/bpf/bpf_util.h @@ -31,13 +31,13 @@ static inline unsigned int bpf_num_possible_cpus(void) # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) #endif -#ifndef sizeof_field -#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) +#ifndef sizeof_member +#define sizeof_member(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) #endif #ifndef offsetofend #define offsetofend(TYPE, MEMBER) \ - (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER)) + (offsetof(TYPE, MEMBER) + sizeof_member(TYPE, MEMBER)) #endif #endif /* __BPF_UTIL__ */ -- 2.17.1
