[PATCH 5.12 696/700] io_uring: add IOPOLL and reserved field checks to IORING_OP_UNLINKAT

[Greg Kroah-Hartman]

From: Jens Axboe <axboe@xxxxxxxxx>

commit 22634bc5620d29765e5199c7b230a372c7ddcda2 upstream.

We can't support IOPOLL with non-pollable request types, and we should
check for unused/reserved fields like we do for other request types.

Fixes: 14a1143b68ee ("io_uring: add support for IORING_OP_UNLINKAT")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Dmitry Kadashev <dkadashev@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/io_uring.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3548,6 +3548,10 @@ static int io_unlinkat_prep(struct io_ki
 	struct io_unlink *un = &req->unlink;
 	const char __user *fname;
 
+	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
+		return -EINVAL;
 	if (unlikely(req->flags & REQ_F_FIXED_FILE))
 		return -EBADF;