In the Linux kernel, the following vulnerability has been resolved:
pinctrl: devicetree: don’t free uninitialized dev_name on error path
dt_remember_or_free_map() duplicates dev_name for each map entry. If
kstrdup_const() fails, dt_free_map() frees dev_name in all num_maps
entries, including entries that have not been initialized.
Some pinctrl drivers, including pinctrl-imx, allocate the map with
kmalloc() and leave dev_name for the core to initialize. The untouched
entries therefore contain uninitialized data which is passed to
kfree_const().
Reproduced on qemu’s mcimx6ul-evk (pinctrl-imx) with failslab injection
while binding the pinctrl-consuming device, under KASAN:
BUG: KASAN: double-free in dt_free_map+0x34/0xa4
Free of addr c425a900 by task init/1
kfree from dt_free_map+0x34/0xa4
dt_free_map from dt_remember_or_free_map+0x184/0x198
dt_remember_or_free_map from pinctrl_dt_to_map+0x33c/0x4c8
pinctrl_dt_to_map from create_pinctrl+0x9c/0x5c0
Initialize all dev_name fields to NULL before duplicating the device
name, making the full-map cleanup safe after a partial failure.
