Re: [RESEND][PATCH] virtio_console: protect max_nr_ports to avoid invalid value
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-08-27 09:00:35
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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?
quoted hunk
Add the protection to guarantee max_nr_ports to get a safe value. Signed-off-by: Xianting Tian <redacted> --- 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 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization