From: Pavel Begunkov asml.silence@gmail.com
mainline inclusion from mainline-5.7-rc6 commit c96874265cd04b4bd4a8e114ac9af039a6d83cfe category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
do_splice() doesn't expect len to be 0. Just always return 0 in this case as splice(2) does.
Fixes: 7d67af2c0134 ("io_uring: add splice(2) support") Reported-by: Jann Horn jannh@google.com Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/io_uring.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 380d29bfbc5a..88eede355116 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2763,16 +2763,19 @@ static int io_splice(struct io_kiocb *req, bool force_nonblock) struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; loff_t *poff_in, *poff_out; - long ret; + long ret = 0;
if (force_nonblock) return -EAGAIN;
poff_in = (sp->off_in == -1) ? NULL : &sp->off_in; poff_out = (sp->off_out == -1) ? NULL : &sp->off_out; - ret = do_splice(in, poff_in, out, poff_out, sp->len, flags); - if (force_nonblock && ret == -EAGAIN) - return -EAGAIN; + + if (sp->len) { + ret = do_splice(in, poff_in, out, poff_out, sp->len, flags); + if (force_nonblock && ret == -EAGAIN) + return -EAGAIN; + }
io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED)); req->flags &= ~REQ_F_NEED_CLEANUP;