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Message-Id: <1515636190-24061-6-git-send-email-keescook@chromium.org> Date: Wed, 10 Jan 2018 18:02:37 -0800 From: Kees Cook <keescook@...omium.org> To: linux-kernel@...r.kernel.org Cc: Kees Cook <keescook@...omium.org>, Linus Torvalds <torvalds@...ux-foundation.org>, David Windsor <dave@...lcore.net>, Alexander Viro <viro@...iv.linux.org.uk>, Andrew Morton <akpm@...ux-foundation.org>, Andy Lutomirski <luto@...nel.org>, Christoph Hellwig <hch@...radead.org>, Christoph Lameter <cl@...ux.com>, "David S. Miller" <davem@...emloft.net>, Laura Abbott <labbott@...hat.com>, Mark Rutland <mark.rutland@....com>, "Martin K. Petersen" <martin.petersen@...cle.com>, Paolo Bonzini <pbonzini@...hat.com>, Christian Borntraeger <borntraeger@...ibm.com>, Christoffer Dall <christoffer.dall@...aro.org>, Dave Kleikamp <dave.kleikamp@...cle.com>, Jan Kara <jack@...e.cz>, Luis de Bethencourt <luisbg@...nel.org>, Marc Zyngier <marc.zyngier@....com>, Rik van Riel <riel@...hat.com>, Matthew Garrett <mjg59@...gle.com>, linux-fsdevel@...r.kernel.org, linux-arch@...r.kernel.org, netdev@...r.kernel.org, linux-mm@...ck.org, kernel-hardening@...ts.openwall.com Subject: [PATCH 05/38] 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 <keescook@...omium.org> --- include/linux/stddef.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) 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 @@ -20,12 +20,20 @@ enum { #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) * * @TYPE: The type of the structure * @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 -- 2.7.4
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