linux-kernel - [PATCH] nbd: fix potential NULL pointer fault in nbd_genl

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:   Mon, 20 Jan 2020 19:23:20 +0800
From:   Sun Ke <sunke32@...wei.com>
To:     <sunke32@...wei.com>, <josef@...icpanda.com>, <axboe@...nel.dk>,
        <mchristi@...hat.com>
CC:     <linux-block@...r.kernel.org>, <nbd@...er.debian.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] nbd: fix potential NULL pointer fault in nbd_genl_disconnect

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@...wei.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