power: sequencing: fix an invalid pointer dereference in error path

[PATCH v2] power: sequencing: fix an invalid pointer dereference in error path

Posted by Bartosz Golaszewski 1 year, 5 months ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

We may end up calling pwrseq_target_free() on a partially initialized
target object whose unit is either NULL or an ERR_PTR(). Avoid
dereferencing invalid memory by adding an appropriate check to
pwrseq_target_free().

Fixes: 249ebf3f65f8 ("power: sequencing: implement the pwrseq core")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-pm/62a3531e-9927-40f8-b587-254a2dfa47ef@stanley.mountain/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
- check for ERR_PTR() in addition to checking for NULL
- only add the check to pwrseq_target_free() as anywhere else unit is
  always set and if it's not then it's another bug that needs fixing

 drivers/power/sequencing/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/power/sequencing/core.c b/drivers/power/sequencing/core.c
index 9c32b07a55e7..0ffc259c6bb6 100644
--- a/drivers/power/sequencing/core.c
+++ b/drivers/power/sequencing/core.c
@@ -212,7 +212,8 @@ pwrseq_target_new(const struct pwrseq_target_data *data)
 
 static void pwrseq_target_free(struct pwrseq_target *target)
 {
-	pwrseq_unit_put(target->unit);
+	if (!IS_ERR_OR_NULL(target->unit))
+		pwrseq_unit_put(target->unit);
 	kfree_const(target->name);
 	kfree(target);
 }
-- 
2.43.0

Re: [PATCH v2] power: sequencing: fix an invalid pointer dereference in error path

Posted by Bartosz Golaszewski 1 year, 5 months ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Fri, 12 Jul 2024 21:40:04 +0200, Bartosz Golaszewski wrote:
> We may end up calling pwrseq_target_free() on a partially initialized
> target object whose unit is either NULL or an ERR_PTR(). Avoid
> dereferencing invalid memory by adding an appropriate check to
> pwrseq_target_free().
> 
> 

Applied, thanks!

[1/1] power: sequencing: fix an invalid pointer dereference in error path
      commit: a19ce320c379e0519b68178c596e43d1d5dda03b

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH v2] power: sequencing: fix an invalid pointer dereference in error path

Posted by Dan Carpenter 1 year, 5 months ago

On Fri, Jul 12, 2024 at 09:40:04PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> We may end up calling pwrseq_target_free() on a partially initialized
> target object whose unit is either NULL or an ERR_PTR(). Avoid
> dereferencing invalid memory by adding an appropriate check to
> pwrseq_target_free().
> 
> Fixes: 249ebf3f65f8 ("power: sequencing: implement the pwrseq core")
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/linux-pm/62a3531e-9927-40f8-b587-254a2dfa47ef@stanley.mountain/
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
> - check for ERR_PTR() in addition to checking for NULL
> - only add the check to pwrseq_target_free() as anywhere else unit is
>   always set and if it's not then it's another bug that needs fixing
> 

Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>

regards,
dan carpenter