[PATCH 6.1.y] io_uring: prevent opcode speculation

[Robert Garcia]

From: Pavel Begunkov <asml.silence@xxxxxxxxx>

[ Upstream commit 1e988c3fe1264708f4f92109203ac5b1d65de50b ]

sqe->opcode is used for different tables, make sure we santitise it
against speculations.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: d3656344fea03 ("io_uring: add lookup table for various opcode needs")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Reviewed-by: Li Zetao <lizetao1@xxxxxxxxxx>
Link: https://lore.kernel.org/r/7eddbf31c8ca0a3947f8ed98271acc2b4349c016.1739568408.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Robert Garcia <rob_garcia@xxxxxxx>
---
 io_uring/io_uring.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index d0d9ff6b87a0..fdb8afdb0135 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2031,6 +2031,8 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 		req->opcode = 0;
 		return io_init_fail_req(req, -EINVAL);
 	}
+	opcode = array_index_nospec(opcode, IORING_OP_LAST);
+
 	def = &io_op_defs[opcode];
 	if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
 		/* enforce forwards compatibility on users */
-- 
2.34.1