io_uring: prevent opcode speculation

isilence · axboe · commit 1e988c3fe126 · 2025-02-15T08:15:12.000-07:00
sqe->opcode is used for different tables, make sure we santitise it against speculations. Cc: stable@vger.kernel.org Fixes: d365634 ("io_uring: add lookup table for various opcode needs") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Li Zetao <lizetao1@huawei.com> Link: https://lore.kernel.org/r/7eddbf31c8ca0a3947f8ed98271acc2b4349c016.1739568408.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
@@ -2045,6 +2045,8 @@ 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_issue_defs[opcode];
 	if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
 		/* enforce forwards compatibility on users */

Original file line number	Diff line number	Diff line change
`@@ -2045,6 +2045,8 @@ static int io_init_req(struct io_ring_ctx ctx, struct io_kiocb req,`
`2045`	`2045`	`req->opcode = 0;`
`2046`	`2046`	`return io_init_fail_req(req, -EINVAL);`
`2047`	`2047`	`}`
	`2048`	`+ opcode = array_index_nospec(opcode, IORING_OP_LAST);`
	`2049`	`+`
`2048`	`2050`	`def = &io_issue_defs[opcode];`
`2049`	`2051`	`if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {`
`2050`	`2052`	`/* enforce forwards compatibility on users */`