From: "Tiezhu Yang" <kernelpatch@126.com>
To: gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] driver core: restrict buffer length in online_store()
Date: Fri, 21 Jul 2017 08:39:04 +0800 (CST) [thread overview]
Message-ID: <665c0831.b66.15d629566c7.Coremail.kernelpatch@126.com> (raw)
According to Documentation/ABI/testing/sysfs-devices-online, in order to
control CPU N's hotplug state, we should write one of 'Yy1Nn0' to the file
/sys/devices/system/cpu/cpuN/online, other values should be invalid. so the
buffer length should be 2, buf[0] is one of 'Yy1Nn0' and buf[1] is '\n'.
without patch:
[root@localhost home]# echo 0test > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
0
[root@localhost home]# echo 1test > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
1
[root@localhost home]# echo ntest > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
0
[root@localhost home]# echo ytest > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
1
[root@localhost home]# echo Ntest > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
0
[root@localhost home]# echo Ytest > /sys/devices/system/cpu/cpu1/online
[root@localhost home]# cat /sys/devices/system/cpu/cpu1/online
1
with patch:
[root@localhost home]# echo 0test > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
[root@localhost home]# echo 1test > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
[root@localhost home]# echo ntest > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
[root@localhost home]# echo ytest > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
[root@localhost home]# echo Ntest > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
[root@localhost home]# echo Ytest > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Invalid argument
Signed-off-by: Tiezhu Yang <kernelpatch@126.com>
---
drivers/base/core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 755451f..6588ed5 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1005,6 +1005,12 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
bool val;
int ret;
+ /* According to Documentation/ABI/testing/sysfs-devices-online,
+ * the buf length should be 2, buf[0]: one of 'Yy1Nn0', buf[1]: '\n'.
+ */
+ if (strlen(buf) != 2)
+ return -EINVAL;
+
ret = strtobool(buf, &val);
if (ret < 0)
return ret;
--
1.8.3.1
next reply other threads:[~2017-07-21 0:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-21 0:39 Tiezhu Yang [this message]
2017-07-21 5:28 ` [PATCH] driver core: restrict buffer length in online_store() Greg KH
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