From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Linux PM <linux-pm@vger.kernel.org>
Cc:     Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: [PATCH v2 4/4] thermal: intel: int340x: Improve int340x_thermal_set_trip_temp()
Date:   Mon, 30 Jan 2023 19:47:43 +0100
Message-ID: <3719164.kQq0lBPeGt@kreacher>
In-Reply-To: <2133431.irdbgypaU6@kreacher>
References: <2133431.irdbgypaU6@kreacher>
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Instead of using snprintf() to populate the ACPI object name in
int340x_thermal_set_trip_temp(), use an appropriate initializer
and make the function fail if its trip argument is greater than 9,
because ACPI object names can only be 4 characters long and it does
not make sense to even try to evaluate objects with longer names (that
argument is guaranteed to be non-negative, because it comes from the
thermal code that will not pass negative trip numbers to zone
callbacks).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2: New patch in v2

---
 drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
===================================================================
--- linux-pm.orig/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
+++ linux-pm/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
@@ -42,10 +42,12 @@ static int int340x_thermal_set_trip_temp
 					 int trip, int temp)
 {
 	struct int34x_thermal_zone *d = zone->devdata;
+	char name[] = {'P', 'A', 'T', '0' + trip, '\0'};
 	acpi_status status;
-	char name[10];
 
-	snprintf(name, sizeof(name), "PAT%d", trip);
+	if (trip > 9)
+		return -EINVAL;
+
 	status = acpi_execute_simple_method(d->adev->handle, name,
 					    millicelsius_to_deci_kelvin(temp));
 	if (ACPI_FAILURE(status))