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virtio_console: validate max_nr_ports before trying to use it

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We calculate nr_ports based on the max_nr_ports:

nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;

If the device advertises a large max_nr_ports, we will end up with a
integer overflow. Fixing this by validating the max_nr_ports and fail
the probe for invalid max_nr_ports in this case.

Cc: Amit Shah <amit@kernel.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20211019070152.8236-3-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2021-10-19 15:01:44 +08:00 committed by Michael S. Tsirkin
parent 63b4ffa4fa
commit 28962ec595
1 changed files with 9 additions and 0 deletions
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9
drivers/char/virtio_console.c
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@ -28,6 +28,7 @@
#include "../tty/hvc/hvc_console.h"
#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
#define VIRTCONS_MAX_PORTS 0x8000
/*
* This is a global struct for storing common data for all the devices
@ -2036,6 +2037,14 @@ static int virtcons_probe(struct virtio_device *vdev)
virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
struct virtio_console_config, max_nr_ports,
&portdev->max_nr_ports) == 0) {
if (portdev->max_nr_ports == 0 ||
portdev->max_nr_ports > VIRTCONS_MAX_PORTS) {
dev_err(&vdev->dev,
"Invalidate max_nr_ports %d",
portdev->max_nr_ports);
err = -EINVAL;
goto free;
}
multiport = true;
}