Messages in this thread Patch in this message | | | From | Xianting Tian <> | Subject | [RESEND][PATCH] virtio_console: protect max_nr_ports to avoid invalid value | Date | Fri, 20 Aug 2021 15:52:19 +0800 |
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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.
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 + /* * This is a global struct for storing common data for all the devices * this driver handles. @@ -2039,6 +2041,9 @@ static int virtcons_probe(struct virtio_device *vdev) multiport = true; } + /* limit max_nr_ports to avoid invalid value from untrusted remote host */ + portdev->max_nr_ports = min_t(u32, portdev->max_nr_ports, MAX_NR_PORTS); + err = init_vqs(portdev); if (err < 0) { dev_err(&vdev->dev, "Error %d initializing vqs\n", err); -- 2.17.1
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