From ee44a1def7ee4c6f9f04a02bfa1a106ee41434d3 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 18 Mar 2025 18:04:29 +0200 Subject: [PATCH] leds: core: Bail out when composed name can't fit the buffer MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit GCC compiler complains about snprintf() calls that may potentially cut the output: drivers/leds/led-core.c:551:78: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=] drivers/leds/led-core.c:554:78: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=] ... Fix these by checking for the potential overflow. This requires to align all the branches to use the same callee, i.e. snprintf(), otherwise the code will be blown up and return different error codes for the different branches. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250318160524.2979982-1-andriy.shevchenko@linux.intel.com Signed-off-by: Lee Jones --- drivers/leds/led-core.c | 43 +++++++++++++++++++++++------------------ 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index 907fc703e0c5f..1a59a4f384791 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -529,6 +529,7 @@ int led_compose_name(struct device *dev, struct led_init_data *init_data, struct led_properties props = {}; struct fwnode_handle *fwnode = init_data->fwnode; const char *devicename = init_data->devicename; + int n; if (!led_classdev_name) return -EINVAL; @@ -542,45 +543,49 @@ int led_compose_name(struct device *dev, struct led_init_data *init_data, * Otherwise the label is prepended with devicename to compose * the final LED class device name. */ - if (!devicename) { - strscpy(led_classdev_name, props.label, - LED_MAX_NAME_SIZE); + if (devicename) { + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", + devicename, props.label); } else { - snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", - devicename, props.label); + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s", props.label); } } else if (props.function || props.color_present) { char tmp_buf[LED_MAX_NAME_SIZE]; if (props.func_enum_present) { - snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d", - props.color_present ? led_colors[props.color] : "", - props.function ?: "", props.func_enum); + n = snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d", + props.color_present ? led_colors[props.color] : "", + props.function ?: "", props.func_enum); } else { - snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s", - props.color_present ? led_colors[props.color] : "", - props.function ?: ""); + n = snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s", + props.color_present ? led_colors[props.color] : "", + props.function ?: ""); } + if (n >= LED_MAX_NAME_SIZE) + return -E2BIG; + if (init_data->devname_mandatory) { - snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", - devicename, tmp_buf); + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", + devicename, tmp_buf); } else { - strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE); - + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s", tmp_buf); } } else if (init_data->default_label) { if (!devicename) { dev_err(dev, "Legacy LED naming requires devicename segment"); return -EINVAL; } - snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", - devicename, init_data->default_label); + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", + devicename, init_data->default_label); } else if (is_of_node(fwnode)) { - strscpy(led_classdev_name, to_of_node(fwnode)->name, - LED_MAX_NAME_SIZE); + n = snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s", + to_of_node(fwnode)->name); } else return -EINVAL; + if (n >= LED_MAX_NAME_SIZE) + return -E2BIG; + return 0; } EXPORT_SYMBOL_GPL(led_compose_name); -- 2.50.1