linux/io_uring/net.c

1810 lines
45 KiB

io_uring/net: add provided buffer support for IORING_OP_SEND It's pretty trivial to wire up provided buffer support for the send side, just like how it's done the receive side. This enables setting up a buffer ring that an application can use to push pending sends to, and then have a send pick a buffer from that ring. One of the challenges with async IO and networking sends is that you can get into reordering conditions if you have more than one inflight at the same time. Consider the following scenario where everything is fine: 1) App queues sendA for socket1 2) App queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, completes successfully, posts CQE 5) sendB is issued, completes successfully, posts CQE All is fine. Requests are always issued in-order, and both complete inline as most sends do. However, if we're flooding socket1 with sends, the following could also result from the same sequence: 1) App queues sendA for socket1 2) App queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, socket1 is full, poll is armed for retry 5) Space frees up in socket1, this triggers sendA retry via task_work 6) sendB is issued, completes successfully, posts CQE 7) sendA is retried, completes successfully, posts CQE Now we've sent sendB before sendA, which can make things unhappy. If both sendA and sendB had been using provided buffers, then it would look as follows instead: 1) App queues dataA for sendA, queues sendA for socket1 2) App queues dataB for sendB queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, socket1 is full, poll is armed for retry 5) Space frees up in socket1, this triggers sendA retry via task_work 6) sendB is issued, picks first buffer (dataA), completes successfully, posts CQE (which says "I sent dataA") 7) sendA is retried, picks first buffer (dataB), completes successfully, posts CQE (which says "I sent dataB") Now we've sent the data in order, and everybody is happy. It's worth noting that this also opens the door for supporting multishot sends, as provided buffers would be a prerequisite for that. Those can trigger either when new buffers are added to the outgoing ring, or (if stalled due to lack of space) when space frees up in the socket. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-02-19 10:46:44 -07:00
io_uring/net: always initialize kmsg->msg.msg_inq upfront [ Upstream commit c6e60a0a68b7e6b3c7e33863a16e8e88ba9eee6f ] syzbot reports that ->msg_inq may get used uinitialized from the following path: BUG: KMSAN: uninit-value in io_recv_buf_select io_uring/net.c:1094 [inline] BUG: KMSAN: uninit-value in io_recv+0x930/0x1f90 io_uring/net.c:1158 io_recv_buf_select io_uring/net.c:1094 [inline] io_recv+0x930/0x1f90 io_uring/net.c:1158 io_issue_sqe+0x420/0x2130 io_uring/io_uring.c:1740 io_queue_sqe io_uring/io_uring.c:1950 [inline] io_req_task_submit+0xfa/0x1d0 io_uring/io_uring.c:1374 io_handle_tw_list+0x55f/0x5c0 io_uring/io_uring.c:1057 tctx_task_work_run+0x109/0x3e0 io_uring/io_uring.c:1121 tctx_task_work+0x6d/0xc0 io_uring/io_uring.c:1139 task_work_run+0x268/0x310 kernel/task_work.c:239 io_run_task_work+0x43a/0x4a0 io_uring/io_uring.h:343 io_cqring_wait io_uring/io_uring.c:2527 [inline] __do_sys_io_uring_enter io_uring/io_uring.c:3439 [inline] __se_sys_io_uring_enter+0x204f/0x4ce0 io_uring/io_uring.c:3330 __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3330 x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f and it is correct, as it's never initialized upfront. Hence the first submission can end up using it uninitialized, if the recv wasn't successful and the networking stack didn't honor ->msg_get_inq being set and filling in the output value of ->msg_inq as requested. Set it to 0 upfront when it's allocated, just to silence this KMSAN warning. There's no side effect of using it uninitialized, it'll just potentially cause the next receive to use a recv value hint that's not accurate. Fixes: c6f32c7d9e09 ("io_uring/net: get rid of ->prep_async() for receive side") Reported-by: syzbot+068ff190354d2f74892f@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-02 16:32:51 -07:00
io_uring/net: fix UAF in io_sendrecv_fail() We should not assume anything about ->free_iov just from REQ_F_ASYNC_DATA but rather rely on REQ_F_NEED_CLEANUP, as we may allocate ->async_data but failed init would leave the field in not consistent state. The easiest solution is to remove removing REQ_F_NEED_CLEANUP and so ->async_data dealloc from io_sendrecv_fail() and let io_send_zc_cleanup() do the job. The catch here is that we also need to prevent double notif flushing, just test it for NULL and zero where it's needed. BUG: KASAN: use-after-free in io_sendrecv_fail+0x3b0/0x3e0 io_uring/net.c:1221 Write of size 8 at addr ffff8880771b4080 by task syz-executor.3/30199 CPU: 1 PID: 30199 Comm: syz-executor.3 Not tainted 6.0.0-rc6-next-20220923-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15e/0x45d mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 io_sendrecv_fail+0x3b0/0x3e0 io_uring/net.c:1221 io_req_complete_failed+0x155/0x1b0 io_uring/io_uring.c:873 io_drain_req io_uring/io_uring.c:1648 [inline] io_queue_sqe_fallback.cold+0x29f/0x788 io_uring/io_uring.c:1931 io_submit_sqe io_uring/io_uring.c:2160 [inline] io_submit_sqes+0x1180/0x1df0 io_uring/io_uring.c:2276 __do_sys_io_uring_enter+0xac6/0x2410 io_uring/io_uring.c:3216 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: c4c0009e0b56e ("io_uring/net: combine fail handlers") Reported-by: syzbot+4c597a574a3f5a251bda@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/23ab8346e407ea50b1198a172c8a97e1cf22915b.1663945875.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-23 16:23:34 +01:00
io_uring/net: ensure socket is marked connected on connect retry 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@vger.kernel.org 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@kernel.dk>
2023-11-03 10:35:40 -06:00
io_uring/net: ensure socket is marked connected on connect retry 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@vger.kernel.org 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@kernel.dk>
2023-11-03 10:35:40 -06:00