linux-kernel - [36/40] bonding: fix error handling if slave is busy (v2)

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

Date:	Tue, 10 Jan 2012 13:45:49 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Stephen Hemminger <shemminger@...tta.com>,
	"David S. Miller" <davem@...emloft.net>
Subject: [36/40] bonding: fix error handling if slave is busy (v2)

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

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

From: stephen hemminger <shemminger@...tta.com>

commit f7d9821a6a9c83450ac35e76d3709e32fd38b76f upstream.

If slave device already has a receive handler registered, then the
error unwind of bonding device enslave function is broken.

The following will leave a pointer to freed memory in the slave
device list, causing a later kernel panic.
# modprobe dummy
# ip li add dummy0-1 link dummy0 type macvlan
# modprobe bonding
# echo +dummy0 >/sys/class/net/bond0/bonding/slaves

The fix is to detach the slave (which removes it from the list)
in the unwind path.

Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
Reviewed-by: Nicolas de Pesloüan <nicolas.2p.debian@...e.fr>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/net/bonding/bond_main.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1905,7 +1905,7 @@ int bond_enslave(struct net_device *bond
 				 "but new slave device does not support netpoll.\n",
 				 bond_dev->name);
 			res = -EBUSY;
-			goto err_close;
+			goto err_detach;
 		}
 	}
 #endif
@@ -1914,7 +1914,7 @@ int bond_enslave(struct net_device *bond

 	res = bond_create_slave_symlinks(bond_dev, slave_dev);
 	if (res)
-		goto err_close;
+		goto err_detach;

 	res = netdev_rx_handler_register(slave_dev, bond_handle_frame,
 					 new_slave);
@@ -1935,6 +1935,11 @@ int bond_enslave(struct net_device *bond
 err_dest_symlinks:
 	bond_destroy_slave_symlinks(bond_dev, slave_dev);

+err_detach:
+	write_lock_bh(&bond->lock);
+	bond_detach_slave(bond, new_slave);
+	write_unlock_bh(&bond->lock);
+
 err_close:
 	dev_close(slave_dev);

--
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/