This is a note to let you know that I've just added the patch titled
io_uring/net: ensure socket is marked connected on connect retry
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-net-ensure-socket-is-marked-connected-on-connect-retry.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f8f9ab2d98116e79d220f1d089df7464ad4e026d Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Fri, 3 Nov 2023 10:35:40 -0600
Subject: io_uring/net: ensure socket is marked connected on connect retry
From: Jens Axboe <axboe@xxxxxxxxx>
commit f8f9ab2d98116e79d220f1d089df7464ad4e026d upstream.
io_uring does non-blocking connection attempts, which can yield some
unexpected results if a connect request is re-attempted by an an
application. This is equivalent to the following sync syscall sequence:
sock = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
connect(sock, &addr, sizeof(addr);
ret == -1 and errno == EINPROGRESS expected here. Now poll for POLLOUT
on sock, and when that returns, we expect the socket to be connected.
But if we follow that procedure with:
connect(sock, &addr, sizeof(addr));
you'd expect ret == -1 and errno == EISCONN here, but you actually get
ret == 0. If we attempt the connection one more time, then we get EISCON
as expected.
io_uring used to do this, but turns out that bluetooth fails with EBADFD
if you attempt to re-connect. Also looks like EISCONN _could_ occur with
this sequence.
Retain the ->in_progress logic, but work-around a potential EISCONN or
EBADFD error and only in those cases look at the sock_error(). This
should work in general and avoid the odd sequence of a repeated connect
request returning success when the socket is already connected.
This is all a side effect of the socket state being in a CONNECTING
state when we get EINPROGRESS, and only a re-connect or other related
operation will turn that into CONNECTED.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 3fb1bd688172 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT")
Link: https://github.com/axboe/liburing/issues/980
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/net.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1461,16 +1461,6 @@ int io_connect(struct io_kiocb *req, uns
int ret;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
- if (connect->in_progress) {
- struct socket *socket;
-
- ret = -ENOTSOCK;
- socket = sock_from_file(req->file);
- if (socket)
- ret = sock_error(socket->sk);
- goto out;
- }
-
if (req_has_async_data(req)) {
io = req->async_data;
} else {
@@ -1490,9 +1480,7 @@ int io_connect(struct io_kiocb *req, uns
&& force_nonblock) {
if (ret == -EINPROGRESS) {
connect->in_progress = true;
- return -EAGAIN;
- }
- if (ret == -ECONNABORTED) {
+ } else if (ret == -ECONNABORTED) {
if (connect->seen_econnaborted)
goto out;
connect->seen_econnaborted = true;
@@ -1506,6 +1494,16 @@ int io_connect(struct io_kiocb *req, uns
memcpy(req->async_data, &__io, sizeof(__io));
return -EAGAIN;
}
+ if (connect->in_progress) {
+ /*
+ * At least bluetooth will return -EBADFD on a re-connect
+ * attempt, and it's (supposedly) also valid to get -EISCONN
+ * which means the previous result is good. For both of these,
+ * grab the sock_error() and use that for the completion.
+ */
+ if (ret == -EBADFD || ret == -EISCONN)
+ ret = sock_error(sock_from_file(req->file)->sk);
+ }
if (ret == -ERESTARTSYS)
ret = -EINTR;
out:
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-6.5/io_uring-net-ensure-socket-is-marked-connected-on-connect-retry.patch
queue-6.5/io_uring-kbuf-allow-the-full-buffer-id-space-for-pro.patch
queue-6.5/nbd-fix-uaf-in-nbd_open.patch
queue-6.5/blk-core-use-pr_warn_ratelimited-in-bio_check_ro.patch
queue-6.5/io_uring-kbuf-fix-check-of-bid-wrapping-in-provided-.patch
queue-6.5/iov_iter-x86-be-consistent-about-the-__user-tag-on-c.patch
