On Thu, Feb 08, 2024 at 02:32:09PM -0500, Stefan Hajnoczi wrote:
> Newlines in virtiofs tags are awkward for users and potential vectors
> for string injection attacks.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
> ---
> fs/fuse/virtio_fs.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
> index 5f1be1da92ce..de9a38efdf1e 100644
> --- a/fs/fuse/virtio_fs.c
> +++ b/fs/fuse/virtio_fs.c
> @@ -323,6 +323,16 @@ static int virtio_fs_read_tag(struct virtio_device *vdev, struct virtio_fs *fs)
> return -ENOMEM;
> memcpy(fs->tag, tag_buf, len);
> fs->tag[len] = '\0';
> +
> + /* While the VIRTIO specification allows any character, newlines are
> + * awkward on mount(8) command-lines and cause problems in the sysfs
> + * "tag" attr and uevent TAG= properties. Forbid them.
> + */
> + if (strchr(fs->tag, '\n')) {
> + dev_err(&vdev->dev, "refusing virtiofs tag with newline character\n");
Please don't let userspace spam mthe kernel log if they are the ones
that are setting the tags. Just make this a debug message instead.
thanks,
greg k-h
