diff options
Diffstat (limited to 'net/mctp/device.c')
| -rw-r--r-- | net/mctp/device.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/net/mctp/device.c b/net/mctp/device.c index ef2755f82f87..f49be882e98e 100644 --- a/net/mctp/device.c +++ b/net/mctp/device.c @@ -6,6 +6,7 @@ * Copyright (c) 2021 Google */ +#include <linux/if_arp.h> #include <linux/if_link.h> #include <linux/mctp.h> #include <linux/netdevice.h> @@ -24,12 +25,25 @@ struct mctp_dump_cb { size_t a_idx; }; -/* unlocked: caller must hold rcu_read_lock */ +/* unlocked: caller must hold rcu_read_lock. + * Returned mctp_dev has its refcount incremented, or NULL if unset. + */ struct mctp_dev *__mctp_dev_get(const struct net_device *dev) { - return rcu_dereference(dev->mctp_ptr); + struct mctp_dev *mdev = rcu_dereference(dev->mctp_ptr); + + /* RCU guarantees that any mdev is still live. + * Zero refcount implies a pending free, return NULL. + */ + if (mdev) + if (!refcount_inc_not_zero(&mdev->refs)) + return NULL; + return mdev; } +/* Returned mctp_dev does not have refcount incremented. The returned pointer + * remains live while rtnl_lock is held, as that prevents mctp_unregister() + */ struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev) { return rtnl_dereference(dev->mctp_ptr); @@ -106,7 +120,7 @@ static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb) struct ifaddrmsg *hdr; struct mctp_dev *mdev; int ifindex; - int idx, rc; + int idx = 0, rc; hdr = nlmsg_data(cb->nlh); // filter by ifindex if requested @@ -123,6 +137,7 @@ static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb) if (mdev) { rc = mctp_dump_dev_addrinfo(mdev, skb, cb); + mctp_dev_put(mdev); // Error indicates full buffer, this // callback will get retried. if (rc < 0) @@ -208,7 +223,7 @@ static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, if (!mdev) return -ENODEV; - if (!mctp_address_ok(addr->s_addr)) + if (!mctp_address_unicast(addr->s_addr)) return -EINVAL; /* Prevent duplicates. Under RTNL so don't need to lock for reading */ @@ -297,7 +312,7 @@ void mctp_dev_hold(struct mctp_dev *mdev) void mctp_dev_put(struct mctp_dev *mdev) { - if (refcount_dec_and_test(&mdev->refs)) { + if (mdev && refcount_dec_and_test(&mdev->refs)) { dev_put(mdev->dev); kfree_rcu(mdev, rcu); } @@ -369,6 +384,7 @@ static size_t mctp_get_link_af_size(const struct net_device *dev, if (!mdev) return 0; ret = nla_total_size(4); /* IFLA_MCTP_NET */ + mctp_dev_put(mdev); return ret; } @@ -412,10 +428,10 @@ static void mctp_unregister(struct net_device *dev) struct mctp_dev *mdev; mdev = mctp_dev_get_rtnl(dev); - if (mctp_known(dev) != (bool)mdev) { + if (mdev && !mctp_known(dev)) { // Sanity check, should match what was set in mctp_register - netdev_warn(dev, "%s: mdev pointer %d but type (%d) match is %d", - __func__, (bool)mdev, mctp_known(dev), dev->type); + netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", + __func__, dev->type); return; } if (!mdev) @@ -439,7 +455,7 @@ static int mctp_register(struct net_device *dev) if (mdev) { if (!mctp_known(dev)) - netdev_warn(dev, "%s: mctp_dev set for unknown type %d", + netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", __func__, dev->type); return 0; } |