Patchwork [153/222] bonding: fix race condition in bonding_store_slaves_active

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Submitter Herton Ronaldo Krzesinski
Date Jan. 16, 2013, 3:55 p.m.
Message ID <1358351822-7675-154-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/212729/
State New
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Comments

Herton Ronaldo Krzesinski - Jan. 16, 2013, 3:55 p.m.
3.5.7.3 -stable review patch.  If anyone has any objections, please let me know.

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

From: "nikolay@redhat.com" <nikolay@redhat.com>

commit e196c0e579902f42cf72414461fb034e5a1ffbf7 upstream.

Race between bonding_store_slaves_active() and slave manipulation
 functions. The bond_for_each_slave use in bonding_store_slaves_active()
 is not protected by any synchronization mechanism.
 NULL pointer dereference is easy to reach.
 Fixed by acquiring the bond->lock for the slave walk.

 v2: Make description text < 75 columns

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 drivers/net/bonding/bond_sysfs.c |    2 ++
 1 file changed, 2 insertions(+)

Patch

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 485bedb..9ea29aa 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1582,6 +1582,7 @@  static ssize_t bonding_store_slaves_active(struct device *d,
 		goto out;
 	}
 
+	read_lock(&bond->lock);
 	bond_for_each_slave(bond, slave, i) {
 		if (!bond_is_active_slave(slave)) {
 			if (new_value)
@@ -1590,6 +1591,7 @@  static ssize_t bonding_store_slaves_active(struct device *d,
 				slave->inactive = 1;
 		}
 	}
+	read_unlock(&bond->lock);
 out:
 	return ret;
 }