path: root/io_uring/rw.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/blk-mq.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/fsnotify.h>
#include <linux/poll.h>
#include <linux/nospec.h>
#include <linux/compat.h>
#include <linux/io_uring/cmd.h>
#include <linux/indirect_call_wrapper.h>

#include <uapi/linux/io_uring.h>

#include "io_uring.h"
#include "opdef.h"
#include "kbuf.h"
#include "alloc_cache.h"
#include "rsrc.h"
#include "poll.h"
#include "rw.h"

struct io_rw {
	/* NOTE: kiocb has the file as the first member, so don't do it here */
	struct kiocb			kiocb;
	u64				addr;
	u32				len;
	rwf_t				flags;
};

static inline bool io_file_supports_nowait(struct io_kiocb *req)
{
	return req->flags & REQ_F_SUPPORT_NOWAIT;
}

#ifdef CONFIG_COMPAT
static int io_iov_compat_buffer_select_prep(struct io_rw *rw)
{
	struct compat_iovec __user *uiov;
	compat_ssize_t clen;

	uiov = u64_to_user_ptr(rw->addr);
	if (!access_ok(uiov, sizeof(*uiov)))
		return -EFAULT;
	if (__get_user(clen, &uiov->iov_len))
		return -EFAULT;
	if (clen < 0)
		return -EINVAL;

	rw->len = clen;
	return 0;
}
#endif

static int io_iov_buffer_select_prep(struct io_kiocb *req)
{
	struct iovec __user *uiov;
	struct iovec iov;
	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);

	if (rw->len != 1)
		return -EINVAL;

#ifdef CONFIG_COMPAT
	if (req->ctx->compat)
		return io_iov_compat_buffer_select_prep(rw);
#endif

	uiov = u64_to_user_ptr(rw->addr);
	if (copy_from_user(&iov, uiov, sizeof(*uiov)))
		return -EFAULT;
	rw->len = iov.iov_len;
	return 0;
}

static int __io_import_iovec(int ddir, struct io_kiocb *req,
			     struct io_async_rw *io,
			     unsigned int issue_flags)
{
	const struct io_issue_def *def = &io_issue_defs[req->opcode];
	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
	struct iovec *iov;
	void __user *buf;
	int nr_segs, ret;
	size_t sqe_len;

	buf = u64_to_user_ptr(rw->addr);
	sqe_len = rw->len;

	if (!def->vectored || req->flags & REQ_F_BUFFER_SELECT) {
		if (io_do_buffer_select(req)) {
			buf = io_buffer_select(req, &sqe_len, issue_flags);
			if (!buf)
				return -ENOBUFS;
			rw->addr = (unsigned long) buf;
			rw->len = sqe_len;
		}

		return import_ubuf(ddir, buf, sqe_len, &io->iter);
	}

	if (io->free_iovec) {
		nr_segs = io->free_iov_nr;
		iov = io->free_iovec;
	} else {
		iov = &io->fast_iov;
		nr_segs = 1;
	}
	ret = __import_iovec(ddir, buf, sqe_len, nr_segs, &iov, &io->iter,
				req->ctx->compat);
	if (unlikely(ret < 0))
		return ret;
	if (iov) {
		req->flags |= REQ_F_NEED_CLEANUP;
		io->free_iov_nr = io->iter.nr_segs;
		kfree(io->free_iovec);
		io->free_iovec = iov;
	}