From 4229a470175be14e1d2648713be8a5e8e8fbea02 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 10 Jan 2018 12:53:20 -0800 Subject: stddef.h: Introduce sizeof_field() The size of fields within a structure is needed in a few places in the kernel already, and will be needed for the usercopy whitelisting when declaring whitelist regions within structures. This creates a dedicated macro and redefines offsetofend() to use it. Existing usage, ignoring the 1200+ lustre assert uses: $ git grep -E 'sizeof\(\(\((struct )?[a-zA-Z_]+ \*\)0\)->' | \ grep -v staging/lustre | wc -l 65 Signed-off-by: Kees Cook --- include/linux/stddef.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'include/linux/stddef.h') diff --git a/include/linux/stddef.h b/include/linux/stddef.h index 2181719fd907..998a4ba28eba 100644 --- a/include/linux/stddef.h +++ b/include/linux/stddef.h @@ -19,6 +19,14 @@ enum { #define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) #endif +/** + * sizeof_field(TYPE, MEMBER) + * + * @TYPE: The structure containing the field of interest + * @MEMBER: The field to return the size of + */ +#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) + /** * offsetofend(TYPE, MEMBER) * @@ -26,6 +34,6 @@ enum { * @MEMBER: The member within the structure to get the end offset of */ #define offsetofend(TYPE, MEMBER) \ - (offsetof(TYPE, MEMBER) + sizeof(((TYPE *)0)->MEMBER)) + (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER)) #endif -- cgit