linux-kernel - [PATCH 2/2] applesmc: Perform some more sanity checking on temperatures

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 for Android: free password hash cracker in your pocket

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

Message-Id: <1292623106-31684-2-git-send-email-mjg@redhat.com>
Date:	Fri, 17 Dec 2010 16:58:26 -0500
From:	Matthew Garrett <mjg@...hat.com>
To:	guenter.roeck@...csson.com
Cc:	rydberg@...omail.se, linux-kernel@...r.kernel.org,
	lm-sensors@...sensors.org, Matthew Garrett <mjg@...hat.com>
Subject: [PATCH 2/2] applesmc: Perform some more sanity checking on temperatures

It seems that the two-byte temperature format is intended to be signed
("sp78" appears to mean "signed, decimal point, 7 bits before, 8 bits
after") and it doesn't seem terribly plausible that we'll get any of these
machines below freezing. It's probably more reasonable to assume that
negative values indicate errors and drop them.

Signed-off-by: Matthew Garrett <mjg@...hat.com>
---
 drivers/hwmon/applesmc.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index 6c98b60..c1eead4 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -744,6 +744,10 @@ static ssize_t applesmc_show_temperature(struct device *dev,
 		return ret;
 
 	if (entry->len == 2) {
+		if (buffer[0] >= 0x80) {
+			/* The two byte format is signed - ignore negative */
+			return -EINVAL;
+		}
 		temp = buffer[0] * 1000;
 		temp += (buffer[1] >> 6) * 250;
 	} else {
-- 
1.7.3.3

--
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/