[PATCH 6.6 325/396] gpio: cdev: sanitize the label before requesting the interrupt

Greg Kroah-Hartman
2024-04-01T16:52:33Z

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

commit b34490879baa847d16fc529c8ea6e6d34f004b38 upstream.

When an interrupt is requested, a procfs directory is created under
"/proc/irq/<irqnum>/ " where is the string passed to one of
the request_irq() variants.

What follows is that the string must not contain the "/" character or
the procfs mkdir operation will fail. We don't have such constraints for
GPIO consumer labels which are used verbatim as interrupt labels for
GPIO irqs. We must therefore sanitize the consumer string before
requesting the interrupt.

Let's replace all "/" with ":".

Cc: stable@vger.kernel.org
Reported-by: Stefan Wahren <wahrenst@gmx.net>
Closes: https://lore.kernel.org/linux-gpio/39fe95cb-aa83-4b8b-8cab-63947a726754@gmx.net/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpio/gpiolib-cdev.c | 38 ++++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)

--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1010,10 +1010,20 @@ static u32 gpio_v2_line_config_debounce_
return 0;
}

+static inline char *make_irq_label(const char *orig)
+{
+ return kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
+}
+
+static inline void free_irq_label(const char *label)
+{
+ kfree(label);
+}
+
static void edge_detector_stop(struct line *line)
{
if (line->irq) {
- free_irq(line->irq, line);
+ free_irq_label(free_irq(line->irq, line));
line->irq = 0;
}

@@ -1038,6 +1048,7 @@ static int edge_detector_setup(struct li
unsigned long irqflags = 0;
u64 eflags;
int irq, ret;
+ char *label;

eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
if (eflags && !kfifo_initialized(&line->req->events)) {
@@ -1074,11 +1085,17 @@ static int edge_detector_setup(struct li
IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
irqflags |= IRQF_ONESHOT;

+ label = make_irq_label(line->req->label);
+ if (!label)
+ return -ENOMEM;
+
/* Request a thread to read the events */
ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
- irqflags, line->req->label, line);
- if (ret)
+ irqflags, label, line);
+ if (ret) {
+ free_irq_label(label);
return ret;
+ }

line->irq = irq;
return 0;
@@ -1943,7 +1960,7 @@ static void lineevent_free(struct lineev
blocking_notifier_chain_unregister(&le->gdev->device_notifier,
&le->device_unregistered_nb);
if (le->irq)
- free_irq(le->irq, le);
+ free_irq_label(free_irq(le->irq, le));
if (le->desc)
gpiod_free(le->desc);
kfree(le->label);
@@ -2091,6 +2108,7 @@ static int lineevent_create(struct gpio_
int fd;
int ret;
int irq, irqflags = 0;
+ char *label;

if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
return -EFAULT;
@@ -2175,15 +2193,23 @@ static int lineevent_create(struct gpio_
if (ret)
goto out_free_le;

+ label = make_irq_label(le->label);
+ if (!label) {
+ ret = -ENOMEM;
+ goto out_free_le;
+ }
+
/* Request a thread to read the events */
ret = request_threaded_irq(irq,
lineevent_irq_handler,
lineevent_irq_thread,
irqflags,
- le->label,
+ label,
le);
- if (ret)
+ if (ret) {
+ free_irq_label(label);
goto out_free_le;
+ }

le->irq = irq;