net-2.6 : V2 - fix dev_get_valid_name
the commit:
commit d90310243fd750240755e217c5faa13e24f41536
Author: Octavian Purdila <opurdila@ixiacom.com>
Date: Wed Nov 18 02:36:59 2009 +0000
net: device name allocation cleanups
introduced a bug when there is a hash collision making impossible
to rename a device with eth%d. This bug is very hard to reproduce
and appears rarely.
The problem is coming from we don't pass a temporary buffer to
__dev_alloc_name but 'dev->name' which is modified by the function.
A detailed explanation is here:
http://marc.info/?l=linux-netdev&m=127417784011987&w=2
Changelog:
V2 : replaced strings comparison by pointers comparison
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Reviewed-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 0aab66d..07a48e2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -954,18 +954,22 @@
}
EXPORT_SYMBOL(dev_alloc_name);
-static int dev_get_valid_name(struct net *net, const char *name, char *buf,
- bool fmt)
+static int dev_get_valid_name(struct net_device *dev, const char *name, bool fmt)
{
+ struct net *net;
+
+ BUG_ON(!dev_net(dev));
+ net = dev_net(dev);
+
if (!dev_valid_name(name))
return -EINVAL;
if (fmt && strchr(name, '%'))
- return __dev_alloc_name(net, name, buf);
+ return dev_alloc_name(dev, name);
else if (__dev_get_by_name(net, name))
return -EEXIST;
- else if (buf != name)
- strlcpy(buf, name, IFNAMSIZ);
+ else if (dev->name != name)
+ strlcpy(dev->name, name, IFNAMSIZ);
return 0;
}
@@ -997,7 +1001,7 @@
memcpy(oldname, dev->name, IFNAMSIZ);
- err = dev_get_valid_name(net, newname, dev->name, 1);
+ err = dev_get_valid_name(dev, newname, 1);
if (err < 0)
return err;
@@ -4965,7 +4969,7 @@
}
}
- ret = dev_get_valid_name(net, dev->name, dev->name, 0);
+ ret = dev_get_valid_name(dev, dev->name, 0);
if (ret)
goto err_uninit;
@@ -5574,7 +5578,7 @@
/* We get here if we can't use the current device name */
if (!pat)
goto out;
- if (dev_get_valid_name(net, pat, dev->name, 1))
+ if (dev_get_valid_name(dev, pat, 1))
goto out;
}