From dddca22636c9062f284e755e2a49fb8863db8a82 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 27 Apr 2021 16:13:52 +0100 Subject: io_uring: dont overlap internal and user req flags CQE flags take one byte that we store in req->flags together with other REQ_F_* internal flags. CQE flags are copied directly into req and then verified that requires some handling on failures, e.g. to make sure that that copy doesn't set some of the internal flags. Move all internal flags to take bits after the first byte, so we don't need extra handling and make it safer overall. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/b8b5b02d1ab9d786fcc7db4a3fe86db6b70b8987.1619536280.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index b0706f047c50..2872f1db6458 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -702,7 +702,8 @@ enum { REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT, REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT, - REQ_F_FAIL_LINK_BIT, + /* first byte is taken by user flags, shift it to not overlap */ + REQ_F_FAIL_LINK_BIT = 8, REQ_F_INFLIGHT_BIT, REQ_F_CUR_POS_BIT, REQ_F_NOWAIT_BIT, @@ -6503,14 +6504,10 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, req->work.creds = NULL; /* enforce forwards compatibility on users */ - if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) { - req->flags = 0; + if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) return -EINVAL; - } - if (unlikely(req->opcode >= IORING_OP_LAST)) return -EINVAL; - if (unlikely(!io_check_restriction(ctx, req, sqe_flags))) return -EACCES; -- cgit v1.2.3-58-ga151