Messages in this thread | | | Date | Fri, 27 Aug 2021 11:00:21 +0200 | From | Greg KH <> | Subject | Re: [RESEND][PATCH] virtio_console: protect max_nr_ports to avoid invalid value |
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On Fri, Aug 20, 2021 at 03:52:19PM +0800, Xianting Tian wrote: > In theory untrusted remote host can pass a big or overflow value > of max_nr_ports to guest, it may cause guest system consumes > a lot of memory when create vqs and other impacts.
How can you have a untrusted host? Can't they do a lot worse things than just this?
> > Add the protection to guarantee max_nr_ports to get a safe value. > > Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> > --- > drivers/char/virtio_console.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index 7eaf303a7..bba985c81 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -29,6 +29,8 @@ > > #define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC) > > +#define MAX_NR_PORTS MAX_NR_HVC_CONSOLES
How was this value picked?
thanks,
greg k-h
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