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generic: add leds_st1202 patch to fix NULL pointer access

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As per @KanjiMonster comment: st1202_dt_init() calls devm_led_classdev_register_ext() before the internal data structures are properly setup, so the leds become visible to user space while being partially initialized, leading to a window where trying to access them causes a NULL pointer access.

Move devm_led_classdev_register_ext() to the last thing to happen during initialization.

Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/17543
Signed-off-by: Robert Marko <robimarko@gmail.com>
This commit is contained in:
Manuel Fombuena 2025-01-14 12:37:20 +00:00 committed by Robert Marko
parent 99431e3150
commit ec8a128cbb
1 changed files with 70 additions and 0 deletions
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70
target/linux/generic/pending-6.6/893-leds_st1202-Fix-NULL-pointer-access-error.patch Normal file
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@ -0,0 +1,70 @@
From e3da313ebcace17f1227566fe1b0d0c3883061f9 Mon Sep 17 00:00:00 2001
From: Manuel Fombuena <fombuena@outlook.com>
Date: Fri, 17 Jan 2025 12:31:49 +0000
Subject: [PATCH 1/5] leds: leds-st1202: fix NULL pointer access on race
condition
st1202_dt_init() calls devm_led_classdev_register_ext() before the
internal data structures are properly setup, so the leds become visible
to user space while being partially initialized, leading to a window
where trying to access them causes a NULL pointer access.
This change moves devm_led_classdev_register_ext() to the last thing to
happen during initialization to eliminate it.
Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
---
drivers/leds/leds-st1202.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
--- a/drivers/leds/leds-st1202.c
+++ b/drivers/leds/leds-st1202.c
@@ -261,8 +261,6 @@ static int st1202_dt_init(struct st1202_
int err, reg;
for_each_available_child_of_node_scoped(dev_of_node(dev), child) {
- struct led_init_data init_data = {};
-
err = of_property_read_u32(child, "reg", &reg);
if (err)
return dev_err_probe(dev, err, "Invalid register\n");
@@ -276,15 +274,6 @@ static int st1202_dt_init(struct st1202_
led->led_cdev.pattern_set = st1202_led_pattern_set;
led->led_cdev.pattern_clear = st1202_led_pattern_clear;
led->led_cdev.default_trigger = "pattern";
-
- init_data.fwnode = led->fwnode;
- init_data.devicename = "st1202";
- init_data.default_label = ":";
-
- err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data);
- if (err < 0)
- return dev_err_probe(dev, err, "Failed to register LED class device\n");
-
led->led_cdev.brightness_set = st1202_brightness_set;
led->led_cdev.brightness_get = st1202_brightness_get;
}
@@ -368,6 +357,7 @@ static int st1202_probe(struct i2c_clien
return ret;
for (int i = 0; i < ST1202_MAX_LEDS; i++) {
+ struct led_init_data init_data = {};
led = &chip->leds[i];
led->chip = chip;
led->led_num = i;
@@ -384,6 +374,15 @@ static int st1202_probe(struct i2c_clien
if (ret < 0)
return dev_err_probe(&client->dev, ret,
"Failed to clear LED pattern\n");
+
+ init_data.fwnode = led->fwnode;
+ init_data.devicename = "st1202";
+ init_data.default_label = ":";
+
+ ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to register LED class device\n");
}
return 0;