From dac7c08f988bbc7208fc7403a5d75d4bb791139c Mon Sep 17 00:00:00 2001 From: Parav Pandit Date: Tue, 12 Feb 2019 14:24:08 -0600 Subject: 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: 4e54795a27f5 ("devlink: Add support for region snapshot read command") Signed-off-by: Parav Pandit Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- net/core/devlink.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/core/devlink.c b/net/core/devlink.c index 312084f76a0a..1d7502a5a651 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -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); -- cgit