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From: Sun Ke <sunke32@huawei.com>
To: <sunke32@huawei.com>, <josef@toxicpanda.com>, <axboe@kernel.dk>,
	<mchristi@redhat.com>
Cc: <linux-block@vger.kernel.org>, <nbd@other.debian.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH] nbd: fix potential NULL pointer fault in nbd_genl_disconnect
Date: Mon, 20 Jan 2020 19:23:20 +0800	[thread overview]
Message-ID: <20200120112320.7375-1-sunke32@huawei.com> (raw)

Open /dev/nbdX first, the config_refs will be 1 and
the pointers in nbd_device are still null. Disconnect
/dev/nbdX, then reference a null recv_workq. The
protection by config_refs in nbd_genl_disconnect is useless.

To fix it, just add a check for a non null task_recv in
nbd_genl_disconnect.

Signed-off-by: Sun Ke <sunke32@huawei.com>
---
 drivers/block/nbd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index b4607dd96185..5e1530bcb81a 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2008,6 +2008,8 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
 		       index);
 		return -EINVAL;
 	}
+	if (!nbd->task_recv)
+		return -EINVAL;
 	if (!refcount_inc_not_zero(&nbd->refs)) {
 		mutex_unlock(&nbd_index_mutex);
 		printk(KERN_ERR "nbd: device at index %d is going down\n",
-- 
2.17.2


                 reply	other threads:[~2020-01-20 11:24 UTC|newest]

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