linux-kernel - [PATCH] thermal_sys: check get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090802140652.16effa08@mail.gmx.de>
Date:	Sun, 2 Aug 2009 14:06:52 +0200
From:	Michael Brunner <mibru@....de>
To:	rui.zhang@...el.com, linux-acpi@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] thermal_sys: check get_temp return value

The return value of the get_temp function is not checked when doing a
thermal zone update. This may lead to a critical shutdown if get_temp
fails and the content of the temp variable is incorrectly set higher
than the critical trip point.
This has been observed on a system with incorrect ACPI implementation
where the corresponding methods were not serialized and therefore
sometimes triggered ACPI errors (AE_ALREADY_EXISTS). The following
critical shutdowns indicated a temperature of 2097 C, which was
obviously wrong.

The patch adds a return value check that jumps over all trip point
evaluations printing a warning if get_temp fails. The trip points are
evaluated again on the next polling interval with successful get_temp
execution.

Signed-off-by: Michael Brunner <mibru@....de>

---

 drivers/thermal/thermal_sys.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 0a69672..4e83c29 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -953,7 +953,12 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)

 	mutex_lock(&tz->lock);

-	tz->ops->get_temp(tz, &temp);
+	if (tz->ops->get_temp(tz, &temp)) {
+		/* get_temp failed - retry it later */
+		printk(KERN_WARNING PREFIX "failed to read out thermal zone "
+		       "%d\n", tz->id);
+		goto leave;
+	}

 	for (count = 0; count < tz->trips; count++) {
 		tz->ops->get_trip_type(tz, count, &trip_type);
@@ -1005,6 +1010,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
 					    THERMAL_TRIPS_NONE);

 	tz->last_temperature = temp;
+
+      leave:
 	if (tz->passive)
 		thermal_zone_device_set_polling(tz, tz->passive_delay);
 	else if (tz->polling_delay)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/