spi: Fix simplification of devm_spi_register_controller

[ Upstream commit 43cc5a0afe4184a7fafe1eba32b5a11bb69c9ce0 ]

This reverts commit 59ebbe40fb51 ("spi: simplify
devm_spi_register_controller").

If devm_add_action() fails in devm_add_action_or_reset(),
devm_spi_unregister() will be called, it decreases the
refcount of 'ctlr->dev' to 0, then it will cause uaf in
the drivers that calling spi_put_controller() in error path.

Fixes: 59ebbe40fb51 ("spi: simplify devm_spi_register_controller")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20220712135504.1055688-1-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d0bbf8f..556d65a 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2949,9 +2949,9 @@ free_bus_id:
 }
 EXPORT_SYMBOL_GPL(spi_register_controller);
 
-static void devm_spi_unregister(void *ctlr)
+static void devm_spi_unregister(struct device *dev, void *res)
 {
-       spi_unregister_controller(ctlr);
+       spi_unregister_controller(*(struct spi_controller **)res);
 }
 
 /**
@@ -2970,13 +2970,22 @@ static void devm_spi_unregister(void *ctlr)
 int devm_spi_register_controller(struct device *dev,
                                 struct spi_controller *ctlr)
 {
+       struct spi_controller **ptr;
        int ret;
 
+       ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
+       if (!ptr)
+               return -ENOMEM;
+
        ret = spi_register_controller(ctlr);
-       if (ret)
-               return ret;
+       if (!ret) {
+               *ptr = ctlr;
+               devres_add(dev, ptr);
+       } else {
+               devres_free(ptr);
+       }
 
-       return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
+       return ret;
 }
 EXPORT_SYMBOL_GPL(devm_spi_register_controller);