[PATCH 6.6 203/252] gpio: cdev: fix missed label sanitizing in debounce_setup()

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6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kent Gibson <warthog618@xxxxxxxxx>

commit 83092341e15d0dfee1caa8dc502f66c815ccd78a upstream.

When adding sanitization of the label, the path through
edge_detector_setup() that leads to debounce_setup() was overlooked.
A request taking this path does not allocate a new label and the
request label is freed twice when the request is released, resulting
in memory corruption.

Add label sanitization to debounce_setup().

Cc: stable@xxxxxxxxxxxxxxx
Fixes: b34490879baa ("gpio: cdev: sanitize the label before requesting the interrupt")
Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx>
[Bartosz: rebased on top of the fix for empty GPIO labels]
Co-developed-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib-cdev.c |   49 +++++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 21 deletions(-)

--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -655,6 +655,25 @@ static u32 line_event_id(int level)
 		       GPIO_V2_LINE_EVENT_FALLING_EDGE;
 }
 
+static inline char *make_irq_label(const char *orig)
+{
+	char *new;
+
+	if (!orig)
+		return NULL;
+
+	new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
+	if (!new)
+		return ERR_PTR(-ENOMEM);
+
+	return new;
+}
+
+static inline void free_irq_label(const char *label)
+{
+	kfree(label);
+}
+
 #ifdef CONFIG_HTE
 
 static enum hte_return process_hw_ts_thread(void *p)
@@ -942,6 +961,7 @@ static int debounce_setup(struct line *l
 {
 	unsigned long irqflags;
 	int ret, level, irq;
+	char *label;
 
 	/* try hardware */
 	ret = gpiod_set_debounce(line->desc, debounce_period_us);
@@ -964,11 +984,17 @@ static int debounce_setup(struct line *l
 			if (irq < 0)
 				return -ENXIO;
 
+			label = make_irq_label(line->req->label);
+			if (IS_ERR(label))
+				return -ENOMEM;
+
 			irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
 			ret = request_irq(irq, debounce_irq_handler, irqflags,
-					  line->req->label, line);
-			if (ret)
+					  label, line);
+			if (ret) {
+				free_irq_label(label);
 				return ret;
+			}
 			line->irq = irq;
 		} else {
 			ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
@@ -1010,25 +1036,6 @@ static u32 gpio_v2_line_config_debounce_
 	return 0;
 }
 
-static inline char *make_irq_label(const char *orig)
-{
-	char *new;
-
-	if (!orig)
-		return NULL;
-
-	new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
-	if (!new)
-		return ERR_PTR(-ENOMEM);
-
-	return new;
-}
-
-static inline void free_irq_label(const char *label)
-{
-	kfree(label);
-}
-
 static void edge_detector_stop(struct line *line)
 {
 	if (line->irq) {






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