5.4-stable review patch. If anyone has any objections, please let me know.
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From: Hans de Goede hansg@kernel.org
[ Upstream commit b6f56a44e4c1014b08859dcf04ed246500e310e5 ]
Since commit 7d5e9737efda ("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: 7d5e9737efda ("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: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/rfkill/rfkill-gpio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/rfkill/rfkill-gpio.c +++ b/net/rfkill/rfkill-gpio.c @@ -78,10 +78,10 @@ static int rfkill_gpio_acpi_probe(struct static int rfkill_gpio_probe(struct platform_device *pdev) { struct rfkill_gpio_data *rfkill; - struct gpio_desc *gpio; + const char *type_name = NULL; const char *name_property; const char *type_property; - const char *type_name; + struct gpio_desc *gpio; int ret;
rfkill = devm_kzalloc(&pdev->dev, sizeof(*rfkill), GFP_KERNEL);