In the Linux kernel, the following vulnerability has been resolved: staging: media: tegra-video:...

In the Linux kernel, the following vulnerability has been resolved:

staging: media: tegra-video: fix device_node use after free

At probe time this code path is followed:

• tegra_csi_init
  • tegra_csi_channels_alloc
    • for_each_child_of_node(node, channel) -- iterates over channels
      • automatically gets 'channel'
        • tegra_csi_channel_alloc()
          • saves into chan->of_node a pointer to the channel OF node
      • automatically gets and puts 'channel'
      • now the node saved in chan->of_node has refcount 0, can disappear
  • tegra_csi_channels_init
    • iterates over channels
      • tegra_csi_channel_init -- uses chan->of_node

After that, chan->of_node keeps storing the node until the device is removed.

of_node_get() the node and of_node_put() it during teardown to avoid any risk.