[RFC 0/1] whitelisting UDP GSO and GRO cmsgs

[Victor Stewart <v@nametag.social>]

so currently all cmsg headers are disabled through sendmsg and recvmsg
operations through io_uring because of
https://www.exploit-db.com/exploits/47779

i think it's time we start whitelisting the good guys though? GSO and
GRO are hugely important for QUIC servers, and together offer a higher
throughput gain than io_uring alone (rate of data transit
considering), thus io_uring is the lesser performance choice for QUIC
servers at the moment.

RE http://vger.kernel.org/lpc_net2018_talks/willemdebruijn-lpc2018-udpgso-paper-DRAFT-1.pdf,
GSO is about +~63% and GRO +~82%.

this patch closes that loophole.

Victor Stewart (1);
   net/socket.c: add __sys_whitelisted_cmsghdrs()

   net/socket.c | 15 ++++++++++++---
   1 file changed, 12 insertions(+), 3 deletions(-)