The patch below does not apply to the 5.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 63ff822358b276137059520cf16e587e8073e80f Mon Sep 17 00:00:00 2001
From: Jens Axboe axboe@kernel.dk Date: Thu, 7 May 2020 14:56:15 -0600 Subject: [PATCH] io_uring: don't use 'fd' for openat/openat2/statx
We currently make some guesses as when to open this fd, but in reality we have no business (or need) to do so at all. In fact, it makes certain things fail, like O_PATH.
Remove the fd lookup from these opcodes, we're just passing the 'fd' to generic helpers anyway. With that, we can also remove the special casing of fd values in io_req_needs_file(), and the 'fd_non_neg' check that we have. And we can ensure that we only read sqe->fd once.
This fixes O_PATH usage with openat/openat2, and ditto statx path side oddities.
Cc: stable@vger.kernel.org: # v5.6 Reported-by: Max Kellermann mk@cm4all.com Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/fs/io_uring.c b/fs/io_uring.c index dd680eb153cb..979d9f977409 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -680,8 +680,6 @@ struct io_op_def { unsigned needs_mm : 1; /* needs req->file assigned */ unsigned needs_file : 1; - /* needs req->file assigned IFF fd is >= 0 */ - unsigned fd_non_neg : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ @@ -784,8 +782,6 @@ static const struct io_op_def io_op_defs[] = { .needs_file = 1, }, [IORING_OP_OPENAT] = { - .needs_file = 1, - .fd_non_neg = 1, .file_table = 1, .needs_fs = 1, }, @@ -799,8 +795,6 @@ static const struct io_op_def io_op_defs[] = { }, [IORING_OP_STATX] = { .needs_mm = 1, - .needs_file = 1, - .fd_non_neg = 1, .needs_fs = 1, .file_table = 1, }, @@ -837,8 +831,6 @@ static const struct io_op_def io_op_defs[] = { .buffer_select = 1, }, [IORING_OP_OPENAT2] = { - .needs_file = 1, - .fd_non_neg = 1, .file_table = 1, .needs_fs = 1, }, @@ -5368,15 +5360,6 @@ static void io_wq_submit_work(struct io_wq_work **workptr) io_steal_work(req, workptr); }
-static int io_req_needs_file(struct io_kiocb *req, int fd) -{ - if (!io_op_defs[req->opcode].needs_file) - return 0; - if ((fd == -1 || fd == AT_FDCWD) && io_op_defs[req->opcode].fd_non_neg) - return 0; - return 1; -} - static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, int index) { @@ -5414,14 +5397,11 @@ static int io_file_get(struct io_submit_state *state, struct io_kiocb *req, }
static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req, - int fd, unsigned int flags) + int fd) { bool fixed;
- if (!io_req_needs_file(req, fd)) - return 0; - - fixed = (flags & IOSQE_FIXED_FILE); + fixed = (req->flags & REQ_F_FIXED_FILE) != 0; if (unlikely(!fixed && req->needs_fixed_file)) return -EBADF;
@@ -5798,7 +5778,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, struct io_submit_state *state, bool async) { unsigned int sqe_flags; - int id, fd; + int id;
/* * All io need record the previous position, if LINK vs DARIN, @@ -5850,8 +5830,10 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, IOSQE_ASYNC | IOSQE_FIXED_FILE | IOSQE_BUFFER_SELECT | IOSQE_IO_LINK);
- fd = READ_ONCE(sqe->fd); - return io_req_set_file(state, req, fd, sqe_flags); + if (!io_op_defs[req->opcode].needs_file) + return 0; + + return io_req_set_file(state, req, READ_ONCE(sqe->fd)); }
static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,