Re: [PATCH net-next v5] udp:allow UDP cmsghdrs through io_uring
From: Soheil Hassas Yeganeh <hidden>
Date: 2020-12-16 22:59:31
Also in:
io-uring
On Wed, Dec 16, 2020 at 5:56 PM Victor Stewart [off-list ref] wrote:
This patch adds PROTO_CMSG_DATA_ONLY to inet_dgram_ops and inet6_dgram_ops so that UDP_SEGMENT (GSO) and UDP_GRO can be used through io_uring. GSO and GRO are vital to bring QUIC servers on par with TCP throughputs, and together offer a higher throughput gain than io_uring alone (rate of data transit considering), thus io_uring is presently the lesser performance choice. 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. Signed-off-by: Victor Stewart <redacted>
Acked-by: Soheil Hassas Yeganeh <redacted> Thanks for adding this! I audied the code and couldn't find an escalation path. +Jann could you please double check?
quoted hunk ↗ jump to hunk
--- net/ipv4/af_inet.c | 1 + net/ipv6/af_inet6.c | 1 + net/socket.c | 8 +++++--- 3 files changed, 7 insertions(+), 3 deletions(-)diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index b7260c8cef2e..c9fd5e7cfd6e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c@@ -1052,6 +1052,7 @@ EXPORT_SYMBOL(inet_stream_ops); const struct proto_ops inet_dgram_ops = { .family = PF_INET, + .flags = PROTO_CMSG_DATA_ONLY, .owner = THIS_MODULE, .release = inet_release, .bind = inet_bind,diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index e648fbebb167..560f45009d06 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c@@ -695,6 +695,7 @@ const struct proto_ops inet6_stream_ops = { const struct proto_ops inet6_dgram_ops = { .family = PF_INET6, + .flags = PROTO_CMSG_DATA_ONLY, .owner = THIS_MODULE, .release = inet6_release, .bind = inet6_bind,diff --git a/net/socket.c b/net/socket.c index 6e6cccc2104f..6995835d6355 100644 --- a/net/socket.c +++ b/net/socket.c@@ -2416,9 +2416,11 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg, long __sys_sendmsg_sock(struct socket *sock, struct msghdr *msg, unsigned int flags) { - /* disallow ancillary data requests from this path */ - if (msg->msg_control || msg->msg_controllen) - return -EINVAL; + if (msg->msg_control || msg->msg_controllen) { + /* disallow ancillary data reqs unless cmsg is plain data */ + if (!(sock->ops->flags & PROTO_CMSG_DATA_ONLY)) + return -EINVAL; + } return ____sys_sendmsg(sock, msg, flags, NULL, 0); } --2.26.2