Re: [RFC] xfrm: convert alg_key to flexible array member

[Steffen Klassert <steffen.klassert@secunet.com>]

On Tue, May 24, 2022 at 01:47:40PM -0700, Stephen Hemminger wrote:
> Iproute2 build generates a warning when built with gcc-12.
> This is because the alg_key in xfrm.h API has zero size
> array element instead of flexible array.
> 
>     CC       xfrm_state.o
> In function ‘xfrm_algo_parse’,
>     inlined from ‘xfrm_state_modify.constprop’ at xfrm_state.c:573:5:
> xfrm_state.c:162:32: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
>   162 |                         buf[j] = val;
>       |                         ~~~~~~~^~~~~
> 
> This patch convert the alg_key into flexible array member.
> There are other zero size arrays here that should be converted as
> well.
> 
> This patch is RFC only since it is only compile tested and
> passes trivial iproute2 tests.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

I've put this today to our test systems and it showed no problems,
so we can integrate it after the merge window.