diff mbox series

[v3] gpio: cdev: sanitize the label before requesting the interrupt

Message ID 20240325090242.14281-1-brgl@bgdev.pl
State New
Headers show
Series [v3] gpio: cdev: sanitize the label before requesting the interrupt | expand

Commit Message

Bartosz Golaszewski March 25, 2024, 9:02 a.m. UTC
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

When an interrupt is requested, a procfs directory is created under
"/proc/irq/<irqnum>/<label>" where <label> 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>
---
v2 -> v3:
- fix a memory leak in error path

v1 -> v2:
- use ':' as the delimiter instead of '-'
- return -ENOMEM if creating the label fails

 drivers/gpio/gpiolib-cdev.c | 38 +++++++++++++++++++++++++++++++------
 1 file changed, 32 insertions(+), 6 deletions(-)

Comments

Linus Walleij March 28, 2024, 8:54 a.m. UTC | #1
On Mon, Mar 25, 2024 at 10:02 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> When an interrupt is requested, a procfs directory is created under
> "/proc/irq/<irqnum>/<label>" where <label> 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>

Good work on this one!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
Bartosz Golaszewski April 2, 2024, 9:48 a.m. UTC | #2
On Tue, Apr 2, 2024 at 11:35 AM Naresh Kamboju
<naresh.kamboju@linaro.org> wrote:
>
> Results from Linaro’s test farm.
> Regressions on arm64, arm, x86_64, and i386 with libgpiod tests.
>
> libgpiod test regressions noticed on Linux stable-rc 6.8, 6.7 and 6.6
> and Linux next and mainline master v6.9-rc2.
>
> Anders bisected and found this first bad commit,
>   gpio: cdev: sanitize the label before requesting the interrupt
>   commit b34490879baa847d16fc529c8ea6e6d34f004b38 upstream.
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> LKFT is running libgpiod test suite version
>   v2.0.1-0-gae275c3 (and also tested v2.1)
>
> libgpiod
>   - _gpiod_edge-event_edge_event_wait_timeout
>   - _gpiod_edge-event_event_copy
>   - _gpiod_edge-event_null_buffer
>   - _gpiod_edge-event_read_both_events
>   - _gpiod_edge-event_read_both_events_blocking
>   - _gpiod_edge-event_read_falling_edge_event
>   - _gpiod_edge-event_read_rising_edge_event
>   - _gpiod_edge-event_read_rising_edge_event_polled
>   - _gpiod_edge-event_reading_more_events_than_the_queue_contains_doesnt_block
>   - _gpiod_edge-event_seqno
>   - _gpiod_line-info_edge_detection_settings
>
> Test log:
> -------
> ok 16 /gpiod/edge-event/edge_event_buffer_max_capacity
> **
> gpiod-test:ERROR:tests-edge-event.c:52:_gpiod_test_func_edge_event_wait_timeout: '_request' should not be NULL
> # gpiod-test:ERROR:tests-edge-event.c:52:_gpiod_test_func_edge_event_wait_timeout: '_request' should not be NULL
> not ok 17 /gpiod/edge-event/edge_event_wait_timeout
> ok 18 /gpiod/edge-event/cannot_request_lines_in_output_mode_with_edge_detection
> **
> gpiod-test:ERROR:tests-edge-event.c:125:_gpiod_test_func_read_both_events: '_request' should not be NULL
> # gpiod-test:ERROR:tests-edge-event.c:125:_gpiod_test_func_read_both_events: '_request' should not be NULL
> not ok 19 /gpiod/edge-event/read_both_events
>
> Steps to reproduce:
> -----
> https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2eUlyN8HN4R1u0RyLwN6hx7IV0I/reproducer
>
> Links:
>  - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240402/testrun/23265184/suite/libgpiod/tests/
>  - https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v6.9-rc2/testrun/23244617/suite/libgpiod/tests/
>  - https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2eUlyN8HN4R1u0RyLwN6hx7IV0I
>  - https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-6.8.y/build/v6.8.2-400-gbffeaccf18b5/testrun/23252337/suite/libgpiod/tests/
>  - https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-6.7.y/build/v6.7.11-433-gb15156435f06/testrun/23252698/suite/libgpiod/tests/
>  - https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-6.6.y/build/v6.6.23-397-g75a2533b74d0/testrun/23254910/suite/libgpiod/tests/
>
> --
> Linaro LKFT
> https://lkft.linaro.org

Hi!

Yes, I confirm the issue, I will have a fix ready soon.

Thanks!
Bart
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index f384fa278764..fa9635610251 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1083,10 +1083,20 @@  static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
 	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;
 	}
 
@@ -1110,6 +1120,7 @@  static int edge_detector_setup(struct line *line,
 	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)) {
@@ -1146,11 +1157,17 @@  static int edge_detector_setup(struct line *line,
 			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;
@@ -1973,7 +1990,7 @@  static void lineevent_free(struct lineevent_state *le)
 		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);
@@ -2114,6 +2131,7 @@  static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	int fd;
 	int ret;
 	int irq, irqflags = 0;
+	char *label;
 
 	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
 		return -EFAULT;
@@ -2198,15 +2216,23 @@  static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	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;