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![Stefan Metzmacher](/assets/img/avatar_default.png)
We need to make sure (at build time) that struct io_cmd_data is not casted to a structure that's larger. Signed-off-by: Stefan Metzmacher <metze@samba.org> Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
171 lines
4 KiB
C
171 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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#include <linux/nospec.h>
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#include <linux/io_uring.h>
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#include <uapi/linux/io_uring.h>
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#include "io_uring.h"
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#include "rsrc.h"
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#include "filetable.h"
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#include "msg_ring.h"
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struct io_msg {
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struct file *file;
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u64 user_data;
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u32 len;
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u32 cmd;
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u32 src_fd;
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u32 dst_fd;
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u32 flags;
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};
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static int io_msg_ring_data(struct io_kiocb *req)
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{
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struct io_ring_ctx *target_ctx = req->file->private_data;
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struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
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if (msg->src_fd || msg->dst_fd || msg->flags)
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return -EINVAL;
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if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0, true))
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return 0;
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return -EOVERFLOW;
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}
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static void io_double_unlock_ctx(struct io_ring_ctx *ctx,
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struct io_ring_ctx *octx,
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unsigned int issue_flags)
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{
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if (issue_flags & IO_URING_F_UNLOCKED)
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mutex_unlock(&ctx->uring_lock);
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mutex_unlock(&octx->uring_lock);
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}
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static int io_double_lock_ctx(struct io_ring_ctx *ctx,
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struct io_ring_ctx *octx,
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unsigned int issue_flags)
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{
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/*
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* To ensure proper ordering between the two ctxs, we can only
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* attempt a trylock on the target. If that fails and we already have
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* the source ctx lock, punt to io-wq.
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*/
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if (!(issue_flags & IO_URING_F_UNLOCKED)) {
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if (!mutex_trylock(&octx->uring_lock))
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return -EAGAIN;
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return 0;
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}
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/* Always grab smallest value ctx first. We know ctx != octx. */
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if (ctx < octx) {
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mutex_lock(&ctx->uring_lock);
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mutex_lock(&octx->uring_lock);
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} else {
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mutex_lock(&octx->uring_lock);
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mutex_lock(&ctx->uring_lock);
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}
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return 0;
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}
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static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
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{
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struct io_ring_ctx *target_ctx = req->file->private_data;
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struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
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struct io_ring_ctx *ctx = req->ctx;
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unsigned long file_ptr;
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struct file *src_file;
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int ret;
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if (target_ctx == ctx)
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return -EINVAL;
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ret = io_double_lock_ctx(ctx, target_ctx, issue_flags);
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if (unlikely(ret))
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return ret;
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ret = -EBADF;
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if (unlikely(msg->src_fd >= ctx->nr_user_files))
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goto out_unlock;
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msg->src_fd = array_index_nospec(msg->src_fd, ctx->nr_user_files);
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file_ptr = io_fixed_file_slot(&ctx->file_table, msg->src_fd)->file_ptr;
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src_file = (struct file *) (file_ptr & FFS_MASK);
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get_file(src_file);
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ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd);
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if (ret < 0) {
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fput(src_file);
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goto out_unlock;
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}
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if (msg->flags & IORING_MSG_RING_CQE_SKIP)
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goto out_unlock;
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/*
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* If this fails, the target still received the file descriptor but
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* wasn't notified of the fact. This means that if this request
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* completes with -EOVERFLOW, then the sender must ensure that a
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* later IORING_OP_MSG_RING delivers the message.
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*/
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if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0, true))
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ret = -EOVERFLOW;
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out_unlock:
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io_double_unlock_ctx(ctx, target_ctx, issue_flags);
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return ret;
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}
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int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
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{
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struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
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if (unlikely(sqe->buf_index || sqe->personality))
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return -EINVAL;
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msg->user_data = READ_ONCE(sqe->off);
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msg->len = READ_ONCE(sqe->len);
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msg->cmd = READ_ONCE(sqe->addr);
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msg->src_fd = READ_ONCE(sqe->addr3);
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msg->dst_fd = READ_ONCE(sqe->file_index);
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msg->flags = READ_ONCE(sqe->msg_ring_flags);
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if (msg->flags & ~IORING_MSG_RING_CQE_SKIP)
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return -EINVAL;
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return 0;
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}
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int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
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{
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struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
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int ret;
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ret = -EBADFD;
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if (!io_is_uring_fops(req->file))
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goto done;
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switch (msg->cmd) {
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case IORING_MSG_DATA:
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ret = io_msg_ring_data(req);
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break;
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case IORING_MSG_SEND_FD:
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ret = io_msg_send_fd(req, issue_flags);
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break;
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default:
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ret = -EINVAL;
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break;
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}
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done:
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if (ret < 0)
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req_set_fail(req);
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io_req_set_res(req, ret, 0);
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/* put file to avoid an attempt to IOPOLL the req */
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io_put_file(req->file);
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req->file = NULL;
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return IOU_OK;
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}
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