From: Parav Pandit <parav@mellanox.com>
Date: Tue, 12 Feb 2019 14:24:08 -0600
Subject: devlink: Fix list access without lock while reading region
Patch-mainline: v5.1-rc1
Git-commit: dac7c08f988bbc7208fc7403a5d75d4bb791139c
References: bsc#1109837
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 <parav@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/core/devlink.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -115,6 +115,8 @@ static struct devlink *devlink_get_from_
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 &&
@@ -3520,13 +3522,13 @@ static int devlink_nl_cmd_region_read_du
if (err)
goto out;
+ 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;
+ goto out_dev;
}
- mutex_lock(&devlink_mutex);
mutex_lock(&devlink->lock);
if (!attrs[DEVLINK_ATTR_REGION_NAME] ||
@@ -3603,6 +3605,7 @@ nla_put_failure:
genlmsg_cancel(skb, hdr);
out_unlock:
mutex_unlock(&devlink->lock);
+out_dev:
mutex_unlock(&devlink_mutex);
out:
return err;