From 5476dfed29ad9b19d4e187685ab71bb9c496f965 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 5 Feb 2021 00:57:59 +0000 Subject: [PATCH] io_uring: clean iov usage for recvmsg buf select Don't pretend we don't know that REQ_F_BUFFER_SELECT for recvmsg always uses fast_iov -- clean up confusing intermixing kmsg->iov and kmsg->fast_iov for buffer select. Also don't init iter with garbage in __io_recvmsg_copy_hdr() only for it to be set shortly after in io_recvmsg(). Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 39bc1df..e07a7fa 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4701,11 +4701,9 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *req, if (req->flags & REQ_F_BUFFER_SELECT) { if (iov_len > 1) return -EINVAL; - if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov))) + if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov))) return -EFAULT; - sr->len = iomsg->iov[0].iov_len; - iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1, - sr->len); + sr->len = iomsg->fast_iov[0].iov_len; iomsg->iov = NULL; } else { ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV, @@ -4748,7 +4746,6 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, if (clen < 0) return -EINVAL; sr->len = clen; - iomsg->iov[0].iov_len = clen; iomsg->iov = NULL; } else { ret = __import_iovec(READ, (struct iovec __user *)uiov, len, @@ -4855,7 +4852,8 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock, if (IS_ERR(kbuf)) return PTR_ERR(kbuf); kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr); - iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov, + kmsg->fast_iov[0].iov_len = req->sr_msg.len; + iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1, req->sr_msg.len); } -- 2.7.4