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dlci: acquire rtnl_lock before calling __dev_get_by_name()

PATCH In review Li Zefan 2 participants 4 messages Jun 26, 2013

Subsystems (2)
Networking Network drivers
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Li Zefan

author
#0 lore raw

PATCH 1/2 dlci: acquire rtnl_lock before calling __dev_get_by_name()

Otherwise the net device returned can be freed at anytime.

Signed-off-by Li Zefan <[email protected]>
Cc [email protected]
---
 drivers/net/wan/dlci.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)
drivers/net/wan/dlci.c +9 -5
index 147614e..1f6e053 100644
@@ -385,20 +385,24 @@ static int dlci_del(struct dlci_add *dlci)
 	struct net_device	*master, *slave;
 	int			err;
 
+	rtnl_lock();
+
 	/* validate slave device */
 	master = __dev_get_by_name(&init_net, dlci->devname);
-	if (!master)
-		return -ENODEV;
+	if (!master) {
+		err = -ENODEV;
+		goto out;
+	}
 
 	if (netif_running(master)) {
-		return -EBUSY;
+		err = -EBUSY;
+		goto out;
 	}
 
 	dlp = netdev_priv(master);
 	slave = dlp->slave;
 	flp = netdev_priv(slave);
 
-	rtnl_lock();
 	err = (*flp->deassoc)(slave, master);
 	if (!err) {
 		list_del(&dlp->list);

@@ -407,8 +411,8 @@ static int dlci_del(struct dlci_add *dlci)
 
 		dev_put(slave);
 	}
+out:
 	rtnl_unlock();
-
 	return err;
 }
Signature · 1 line
1.8.0.2
author
#1 lore raw

PATCH 2/2 dlci: validate the net device in dlci_del()

We triggered an oops while running trinity with 3.4 kernel:

BUG: unable to handle kernel paging request at 0000000100000d07
IP: [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
PGD 640c0d067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
CPU 3
...
Pid: 7302, comm: trinity-child3 Not tainted 3.4.24.09+ 40 Huawei Technologies Co., Ltd. Tecal RH2285          /BC11BTSA
RIP: 0010:[<ffffffffa0109738>]  [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
...
Call Trace:
  [<ffffffff8137c5c3>] sock_ioctl+0x153/0x280
  [<ffffffff81195494>] do_vfs_ioctl+0xa4/0x5e0
  [<ffffffff8118354a>] ? fget_light+0x3ea/0x490
  [<ffffffff81195a1f>] sys_ioctl+0x4f/0x80
  [<ffffffff81478b69>] system_call_fastpath+0x16/0x1b

...

It's because the net device is not a dlci device.

Reported-by Li Jinyue <[email protected]>
Signed-off-by Li Zefan <[email protected]>
Cc [email protected]
---
 drivers/net/wan/dlci.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
drivers/net/wan/dlci.c +12 -0
index 1f6e053..6a8a382 100644
@@ -384,6 +384,7 @@ static int dlci_del(struct dlci_add *dlci)
 	struct frad_local	*flp;
 	struct net_device	*master, *slave;
 	int			err;
+	bool			found = false;
 
 	rtnl_lock();
 

@@ -394,6 +395,17 @@ static int dlci_del(struct dlci_add *dlci)
 		goto out;
 	}
 
+	list_for_each_entry(dlp, &dlci_devs, list) {
+		if (dlp->master == master) {
+			found = true;
+			break;
+		}
+	}
+	if (!found) {
+		err = -ENODEV;
+		goto out;
+	}
+
 	if (netif_running(master)) {
 		err = -EBUSY;
 		goto out;
Signature · 1 line
1.8.0.2
maintainer
#2 lore raw

Re: [PATCH 2/2] dlci: validate the net device in dlci_del()

In reply to Li Zefan

From: Li Zefan <[email protected]>
Date: Wed, 26 Jun 2013 15:31:58 +0800

Quoted 17 lines

We triggered an oops while running trinity with 3.4 kernel:

BUG: unable to handle kernel paging request at 0000000100000d07
IP: [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
PGD 640c0d067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
CPU 3
...
Pid: 7302, comm: trinity-child3 Not tainted 3.4.24.09+ 40 Huawei Technologies Co., Ltd. Tecal RH2285          /BC11BTSA
RIP: 0010:[<ffffffffa0109738>]  [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
...
Call Trace:
  [<ffffffff8137c5c3>] sock_ioctl+0x153/0x280
  [<ffffffff81195494>] do_vfs_ioctl+0xa4/0x5e0
  [<ffffffff8118354a>] ? fget_light+0x3ea/0x490
  [<ffffffff81195a1f>] sys_ioctl+0x4f/0x80
  [<ffffffff81478b69>] system_call_fastpath+0x16/0x1b
Quoted 6 lines

...

It's because the net device is not a dlci device.

Reported-by Li Jinyue <[email protected]>
Signed-off-by Li Zefan <[email protected]>

Applied and queued up for -stable.