linux-kernel - [PATCH 079/105] tuntap: forbid changing mq flag for persistent device

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 for Android: free password hash cracker in your pocket

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

Message-Id: <1372445527-24414-80-git-send-email-kamal@canonical.com>
Date:	Fri, 28 Jun 2013 11:51:41 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	"Michael S. Tsirkin" <mst@...hat.com>,
	Jason Wang <jasowang@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 079/105] tuntap: forbid changing mq flag for persistent device

3.8.13.4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@...hat.com>

[ Upstream commit 8e6d91ae0917bf934ed86411148f79d904728d51 ]

We currently allow changing the mq flag (IFF_MULTI_QUEUE) for a persistent
device. This will result a mismatch between the number the queues in netdev and
tuntap. This is because we only allocate a 1q netdevice when IFF_MULTI_QUEUE was
not specified, so when we set the IFF_MULTI_QUEUE and try to attach more queues
later, netif_set_real_num_tx_queues() may fail which result a single queue
netdevice with multiple sockets attached.

Solve this by disallowing changing the mq flag for persistent device.

Bug was introduced by commit edfb6a148ce62e5e19354a1dcd9a34e00815c2a1
(tuntap: reduce memory using of queues).

Reported-by: Sriram Narasimhan <sriram.narasimhan@...com>
Cc: Michael S. Tsirkin <mst@...hat.com>
Signed-off-by: Jason Wang <jasowang@...hat.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 drivers/net/tun.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 522dc0a..2129cf90 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1585,6 +1585,10 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		else
 			return -EINVAL;
 
+		if (!!(ifr->ifr_flags & IFF_MULTI_QUEUE) !=
+		    !!(tun->flags & TUN_TAP_MQ))
+			return -EINVAL;
+
 		if (tun_not_capable(tun))
 			return -EPERM;
 		err = security_tun_dev_open(tun->security);
-- 
1.8.1.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/