commit b6f56a44e4c1014b08859dcf04ed246500e310e5 upstream.
Since commit 7d5e9737ef ("net: rfkill: gpio: get the name and type from
device property") rfkill_find_type() gets called with the possibly
uninitialized "const char *type_name;" local variable.
On x86 systems when rfkill-gpio binds to a "BCM4752" or "LNV4752"
acpi_device, the rfkill->type is set based on the ACPI acpi_device_id:
rfkill->type = (unsigned)id->driver_data;
and there is no "type" property so device_property_read_string() will fail
and leave type_name uninitialized, leading to a potential crash.
rfkill_find_type() does accept a NULL pointer, fix the potential crash
by initializing type_name to NULL.
Note likely sofar this has not been caught because:
1. Not many x86 machines actually have a "BCM4752"/"LNV4752" acpi_device
2. The stack happened to contain NULL where type_name is stored
Fixes: 7d5e9737ef ("net: rfkill: gpio: get the name and type from device property")
Cc: stable@vger.kernel.org
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hansg@kernel.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20250913113515.21698-1-hansg@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
21ba85d9d5