[PATCH V4 07/14] i3c: master: Fix potential UAF in i3c_device_match()

[Adrian Hunter]

i3c_device_match() dereferences i3cdev->desc without holding the bus
normal-use lock.  Since the descriptor pointer can be replaced
concurrently, the dereference can race with descriptor replacement and
result in a use-after-free.

Protect access to i3cdev->desc with the normal-use lock.  While the lock
is held, the descriptor is guaranteed to remain valid, so the NULL check
is also unnecessary and can be removed.

This change depends on "i3c: master: Fix recursive locking during device
registration".  Prior to that change, taking the normal-use lock in
i3c_device_match() could recurse on bus->lock during device
registration.

This fixes "i3c: master: match I3C device through DT and ACPI".

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
---


Changes in V4:

	None

Changes in V3:

	New patch


 drivers/i3c/master.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index ee771ac0b203..83e04a2c202a 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -347,8 +347,10 @@ static int i3c_device_match(struct device *dev, const struct device_driver *drv)
 	i3cdev = dev_to_i3cdev(dev);
 	i3cdrv = drv_to_i3cdrv(drv);
 
-	if (i3cdev->desc && i3cdev->desc->boardinfo)
+	i3c_bus_normaluse_lock(i3cdev->bus);
+	if (i3cdev->desc->boardinfo)
 		static_addr_method = i3cdev->desc->boardinfo->static_addr_method;
+	i3c_bus_normaluse_unlock(i3cdev->bus);
 
 	/*
 	 * SETAASA-based devices need not always have a matching ID since
-- 
2.53.0