io_uring: fix {SQ,IO}POLL with unsupported opcodes

IORING_SETUP_IOPOLL is defined only for read/write, other opcodes should
be disallowed, otherwise it'll get an error as below. Also refuse
open/close with SQPOLL, as the polling thread wouldn't know which file
table to use.

RIP: 0010:io_iopoll_getevents+0x111/0x5a0
Call Trace:
 ? _raw_spin_unlock_irqrestore+0x24/0x40
 ? do_send_sig_info+0x64/0x90
 io_iopoll_reap_events.part.0+0x5e/0xa0
 io_ring_ctx_wait_and_kill+0x132/0x1c0
 io_uring_release+0x20/0x30
 __fput+0xcd/0x230
 ____fput+0xe/0x10
 task_work_run+0x67/0xa0
 do_exit+0x353/0xb10
 ? handle_mm_fault+0xd4/0x200
 ? syscall_trace_enter+0x18c/0x2c0
 do_group_exit+0x43/0xa0
 __x64_sys_exit_group+0x18/0x20
 do_syscall_64+0x60/0x1e0
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: allow provide/remove buffers and files update]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 417b710..c627dd9 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2766,6 +2766,8 @@ static int __io_splice_prep(struct io_kiocb *req,
 
        if (req->flags & REQ_F_NEED_CLEANUP)
                return 0;
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
 
        sp->file_in = NULL;
        sp->len = READ_ONCE(sqe->len);
@@ -2966,6 +2968,8 @@ static int io_fallocate_prep(struct io_kiocb *req,
 {
        if (sqe->ioprio || sqe->buf_index || sqe->rw_flags)
                return -EINVAL;
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
 
        req->sync.off = READ_ONCE(sqe->off);
        req->sync.len = READ_ONCE(sqe->addr);
@@ -2991,6 +2995,8 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        const char __user *fname;
        int ret;
 
+       if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
+               return -EINVAL;
        if (sqe->ioprio || sqe->buf_index)
                return -EINVAL;
        if (req->flags & REQ_F_FIXED_FILE)
@@ -3024,6 +3030,8 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        size_t len;
        int ret;
 
+       if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
+               return -EINVAL;
        if (sqe->ioprio || sqe->buf_index)
                return -EINVAL;
        if (req->flags & REQ_F_FIXED_FILE)
@@ -3263,6 +3271,8 @@ static int io_epoll_ctl_prep(struct io_kiocb *req,
 #if defined(CONFIG_EPOLL)
        if (sqe->ioprio || sqe->buf_index)
                return -EINVAL;
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
 
        req->epoll.epfd = READ_ONCE(sqe->fd);
        req->epoll.op = READ_ONCE(sqe->len);
@@ -3307,6 +3317,8 @@ static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
        if (sqe->ioprio || sqe->buf_index || sqe->off)
                return -EINVAL;
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
 
        req->madvise.addr = READ_ONCE(sqe->addr);
        req->madvise.len = READ_ONCE(sqe->len);
@@ -3341,6 +3353,8 @@ static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        if (sqe->ioprio || sqe->buf_index || sqe->addr)
                return -EINVAL;
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
 
        req->fadvise.offset = READ_ONCE(sqe->off);
        req->fadvise.len = READ_ONCE(sqe->len);
@@ -3374,6 +3388,8 @@ static int io_fadvise(struct io_kiocb *req, bool force_nonblock)
 
 static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
+       if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+               return -EINVAL;
        if (sqe->ioprio || sqe->buf_index)
                return -EINVAL;
        if (req->flags & REQ_F_FIXED_FILE)
@@ -3418,6 +3434,8 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
         */
        req->work.flags |= IO_WQ_WORK_NO_CANCEL;
 
+       if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
+               return -EINVAL;
        if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
            sqe->rw_flags || sqe->buf_index)
                return -EINVAL;