From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Thu, 12 Dec 2013 07:05:33 +0000 (+0100)
Subject: hwmon: Prevent some divide by zeros in FAN_TO_REG()
X-Git-Tag: v3.4.87~18
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=57591712825e050d0c70cd0526492de4d5ad2905;p=thirdparty%2Fkernel%2Fstable.git

hwmon: Prevent some divide by zeros in FAN_TO_REG()

commit 3806b45ba4655147a011df03242cc197ab986c43 upstream.

The "rpm * div" operations can overflow here, so this patch adds an
upper limit to rpm to prevent that.  Jean Delvare helped me with this
patch.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Roger Lucas <vt8231@hiddenengine.co.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/hwmon/lm78.c b/drivers/hwmon/lm78.c
index f6bc414e1e91e..8d6a133e4d877 100644
--- a/drivers/hwmon/lm78.c
+++ b/drivers/hwmon/lm78.c
@@ -94,6 +94,8 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 {
 	if (rpm <= 0)
 		return 255;
+	if (rpm > 1350000)
+		return 1;
 	return SENSORS_LIMIT((1350000 + rpm * div / 2) / (rpm * div), 1, 254);
 }
 
diff --git a/drivers/hwmon/sis5595.c b/drivers/hwmon/sis5595.c
index 6c4d8eb9b7ca5..098489cefc57f 100644
--- a/drivers/hwmon/sis5595.c
+++ b/drivers/hwmon/sis5595.c
@@ -141,6 +141,8 @@ static inline u8 FAN_TO_REG(long rpm, int div)
 {
 	if (rpm <= 0)
 		return 255;
+	if (rpm > 1350000)
+		return 1;
 	return SENSORS_LIMIT((1350000 + rpm * div / 2) / (rpm * div), 1, 254);
 }
 
diff --git a/drivers/hwmon/vt8231.c b/drivers/hwmon/vt8231.c
index 386a845380107..0a287e023603b 100644
--- a/drivers/hwmon/vt8231.c
+++ b/drivers/hwmon/vt8231.c
@@ -145,7 +145,7 @@ static const u8 regtempmin[] = { 0x3a, 0x3e, 0x2c, 0x2e, 0x30, 0x32 };
  */
 static inline u8 FAN_TO_REG(long rpm, int div)
 {
-	if (rpm == 0)
+	if (rpm <= 0 || rpm > 1310720)
 		return 0;
 	return SENSORS_LIMIT(1310720 / (rpm * div), 1, 255);
 }