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From: Kimberly Brown <kimbrownkd@gmail.com>
To: Michael Kelley <mikelley@microsoft.com>,
	Long Li <longli@microsoft.com>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	Dexuan Cui <decui@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	devel@linuxdriverproject.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Drivers: hv: vmbus: Add mutex lock to channel show functions
Date: Mon, 21 Jan 2019 21:07:59 -0500
Message-ID: <20190122020759.GA4054@ubu-Virtual-Machine> (raw)

The channel level "_show" functions are vulnerable to race conditions.
Add a mutex lock and unlock around the call to the channel level "_show"
functions in vmbus_chan_attr_show().

This problem was discussed here: https://lkml.org/lkml/2018/10/18/830

Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
---
 drivers/hv/vmbus_drv.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 403fee01572c..e8189bc168da 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1414,6 +1414,7 @@ static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
 		= container_of(attr, struct vmbus_chan_attribute, attr);
 	const struct vmbus_channel *chan
 		= container_of(kobj, struct vmbus_channel, kobj);
+	ssize_t ret;
 
 	if (!attribute->show)
 		return -EIO;
@@ -1421,7 +1422,10 @@ static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
 	if (chan->state != CHANNEL_OPENED_STATE)
 		return -EINVAL;
 
-	return attribute->show(chan, buf);
+	mutex_lock(&vmbus_connection.channel_mutex);
+	ret = attribute->show(chan, buf);
+	mutex_unlock(&vmbus_connection.channel_mutex);
+	return ret;
 }
 
 static const struct sysfs_ops vmbus_chan_sysfs_ops = {
-- 
2.17.1


             reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-22  2:07 Kimberly Brown [this message]
2019-01-22  3:46 ` Dexuan Cui
2019-01-22  6:42   ` Kimberly Brown
2019-01-22 18:40     ` Dexuan Cui
2019-01-28 19:58       ` Kimberly Brown
2019-01-29 19:20         ` Dexuan Cui
2019-01-31 15:19           ` Sasha Levin
2019-01-31 16:45             ` Michael Kelley
2019-01-31 17:47               ` Kimberly Brown
2019-02-01 14:13                 ` Sasha Levin
2019-02-01 18:24                 ` Dexuan Cui
2019-02-02 20:07                   ` Kimberly Brown
2019-02-15  1:54                     ` Sasha Levin
2019-02-15  2:27                       ` Kimberly Brown
2019-02-22  3:46 ` [PATCH v2 0/2] Fix a race condition vulnerability in "_show" functions Kimberly Brown
2019-02-22  3:47   ` [PATCH v2 1/2] Drivers: hv: vmbus: Refactor chan->state if statement Kimberly Brown
2019-02-24 16:54     ` Michael Kelley
2019-02-22  3:47   ` [PATCH v2 2/2] Drivers: hv: vmbus: Add a channel ring buffer mutex lock Kimberly Brown
2019-02-24 16:53     ` Michael Kelley
2019-02-26  6:24       ` Kimberly Brown
2019-03-14 20:04   ` [PATCH v3 0/3] Drivers: hv: vmbus: Fix a race condition in "_show" functions Kimberly Brown
2019-03-14 20:05     ` [PATCH v3 1/3] Drivers: hv: vmbus: Refactor chan->state if statement Kimberly Brown
2019-03-14 20:05     ` [PATCH v3 2/3] Drivers: hv: vmbus: Set ring_info field to 0 and remove memset Kimberly Brown
2019-03-29 16:01       ` Michael Kelley
2019-03-14 20:05     ` [PATCH v3 3/3] Drivers: hv: vmbus: Fix race condition with new ring_buffer_info mutex Kimberly Brown
2019-03-14 22:45       ` Stephen Hemminger
2019-03-17  1:49         ` Kimberly Brown
2019-03-20 20:06           ` Stephen Hemminger
2019-03-21  3:47             ` Kimberly Brown
2019-03-21 16:04               ` Michael Kelley
2019-03-28  4:30                 ` Kimberly Brown
2019-03-28 18:42                   ` Stephen Hemminger
2019-03-29 16:04       ` Michael Kelley
2019-04-10 22:59     ` [PATCH v3 0/3] Drivers: hv: vmbus: Fix a race condition in "_show" functions Sasha Levin

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