Re: [PATCH 19/32] afs: Use mem_to_flex_dup() with struct afs_acl

On Thu, May 12, 2022 at 10:41:05PM +0100, David Howells wrote:

Kees Cook keescook@chromium.org wrote:

...

struct afs_acl {

• u32 size;
• u8 data[];

• DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u32, size);
• DECLARE_FLEX_ARRAY_ELEMENTS(u8, data);

};

Oof... That's really quite unpleasant syntax. Is it not possible to have mem_to_flex_dup() and friends work without that? You are telling them the fields they have to fill in.

Other threads discussed this too. I'm hoping to have something more flexible (pardon the pun) in v2.

[...] or:

ret = mem_to_flex_dup(&acl, buffer, size, GFP_KERNEL); if (ret < 0)

(or use != 0 rather than < 0)

Sure, I can make the tests more explicit. The kerndoc, etc all shows it's using < 0 for errors.