Re: [PATCH v13 01/12] spmi: Fix potential use-after-free by grabbing of_node reference

[Abel Vesa]

On 26-07-21 11:36:15, AngeloGioacchino Del Regno wrote:
> As noticed by Sashiko during a review run of an unrelated patch,
> in of_spmi_register_devices(), for_each_available_child_of_node()
> is used to loop through children, and to also assign a node to a
> newly created SPMI child device.
> 
> Problem is that the refcount is dropped at every iteration so, in
> the specific case of DT overlays, a use-after-free may occur when
> an overlay is dynamically unloaded!
> 
> To resolve this, increase the of_node refcount when assigning (in
> function of_spmi_register_devices) and release the reference in
> spmi_device_remove().
> 
> Fixes: bc32bbd04011 ("spmi: Set fwnode for spmi devices")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Sashiko Bot <sashiko-bot@xxxxxxxxxx>
> Closes: https://sashiko.dev/#/patchset/20260608100949.36309-1-angelogioacchino.delregno@xxxxxxxxxxxxx?part=2
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>

Reviewed-by: Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx>