[PATCH 5.19 0270/1157] spi: Fix simplification of devm_spi_register_controller

Greg Kroah-Hartman
2022-08-15T23:02:20Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ 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>
---
drivers/spi/spi.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 62aa3f062f3d..2c616024f7c0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3050,9 +3050,9 @@ int spi_register_controller(struct spi_controller *ctlr)
}
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);
}

/**
@@ -3071,13 +3071,22 @@ 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);

--
2.35.1