Re: [PATCH net-next v4 5/7] ipv4: convert do_ip_getsockopt() to sockopt_t

[Jiayuan Chen <jiayuan.chen@linux.dev>]

On 11/3/26 7:01 PM, Breno Leitao wrote:
> Convert the SOL_IP switch and ip_mroute_getsockopt() to sockopt_t, its
> last leaf on a sockptr_t pair. The IP_MSFILTER and MCAST_MSFILTER
> bridges go away.
>
> ip_getsockopt() builds the sockopt_t with sockopt_init_user() and
> writes optlen back unconditionally, because IP_OPTIONS and others
> report a length and can then fail. ip_mc_msfget() therefore stores its
> length only after its last copy, so a copy failure can't report a
> changed one.
>
> The write-back also happens before the netfilter fallback, so an
> unwritable optlen turns any error into -EFAULT and skips the fallback.
> Likewise optlen is now read before the level check and the MRT_*
> dispatch, so an unreadable or negative one wins over -EOPNOTSUPP.
>
> IP_OPTIONS with no options set and IP_PKTOPTIONS used to return the
> result of copy_to_sockptr(), the number of bytes not copied, so an
> unwritable optlen made getsockopt() return 4. They now return -EFAULT.
>
> sol_ip_sockopt() builds the sockopt_t with sockptr_to_sockopt() and
> stores optlen back as well. This extra code will go away when we
> convert sol_ip_sockopt() to talk sockopt as well, but for now we are
> converting the leaves.
>
> Acked-by: Stanislav Fomichev <sdf@fomichev.me>
> Acked-by: Ido Schimmel <idosch@nvidia.com>
> Signed-off-by: Breno Leitao <leitao@debian.org>


Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>