From: Pavel Begunkov asml.silence@gmail.com
commit 2d280bc8930ba9ed1705cfd548c6c8924949eaf1 upstream.
__io_compat_recvmsg_copy_hdr() with REQ_F_BUFFER_SELECT reads out iov len but never assigns it to iov/fast_iov, leaving sr->len with garbage. Hopefully, following io_buffer_select() truncates it to the selected buffer size, but the value is still may be under what was specified.
Cc: stable@vger.kernel.org # 5.7 Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4300,7 +4300,8 @@ static int __io_compat_recvmsg_copy_hdr( return -EFAULT; if (clen < 0) return -EINVAL; - sr->len = iomsg->iov[0].iov_len; + sr->len = clen; + iomsg->iov[0].iov_len = clen; iomsg->iov = NULL; } else { ret = compat_import_iovec(READ, uiov, len, UIO_FASTIOV,