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devlink: Fix list access without lock while reading region 

While finding the devlink device during region reading,
devlink device list is accessed and devlink device is
returned without holding a lock. This could lead to use-after-free
accesses.

While at it, add lockdep assert to ensure that all future callers hold
the lock when calling devlink_get_from_attrs().

Fixes: 4e54795a27 ("devlink: Add support for region snapshot read command")
Signed-off-by: Parav Pandit <parav@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Parav Pandit 2019-02-12 14:24:08 -06:00 committed by David S. Miller
parent fdd41ec21e
commit dac7c08f98
1 changed files with 5 additions and 2 deletions
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7
net/core/devlink.c
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@ -116,6 +116,8 @@ static struct devlink *devlink_get_from_attrs(struct net *net,
busname = nla_data(attrs[DEVLINK_ATTR_BUS_NAME]);
devname = nla_data(attrs[DEVLINK_ATTR_DEV_NAME]);
lockdep_assert_held(&devlink_mutex);
list_for_each_entry(devlink, &devlink_list, list) {
if (strcmp(devlink->dev->bus->name, busname) == 0 &&
strcmp(dev_name(devlink->dev), devname) == 0 &&
@ -3645,13 +3647,13 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
if (err)
goto out_free;
mutex_lock(&devlink_mutex);
devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
if (IS_ERR(devlink)) {
err = PTR_ERR(devlink);
goto out_free;
goto out_dev;
}
mutex_lock(&devlink_mutex);
mutex_lock(&devlink->lock);
if (!attrs[DEVLINK_ATTR_REGION_NAME] ||
@ -3729,6 +3731,7 @@ nla_put_failure:
genlmsg_cancel(skb, hdr);
out_unlock:
mutex_unlock(&devlink->lock);
out_dev:
mutex_unlock(&devlink_mutex);
out_free:
kfree(attrs);