From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 8e9eacad7ec7a9cbf262649ebf1fa6e6f6cc7d82 ]
The MPTCP endpoint list is under RCU protection, guarded by the pernet spinlock. mptcp_nl_cmd_set_flags() traverses the list without acquiring the spin-lock nor under the RCU critical section.
This change addresses the issue performing the lookup and the endpoint update under the pernet spinlock.
Fixes: 0f9f696a502e ("mptcp: add set_flags command in PM netlink") Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/pm_netlink.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index ad3dc9c6c5310..35abcce604b4d 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -469,6 +469,20 @@ __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id) return NULL; }
+static struct mptcp_pm_addr_entry * +__lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info, + bool lookup_by_id) +{ + struct mptcp_pm_addr_entry *entry; + + list_for_each_entry(entry, &pernet->local_addr_list, list) { + if ((!lookup_by_id && addresses_equal(&entry->addr, info, true)) || + (lookup_by_id && entry->addr.id == info->id)) + return entry; + } + return NULL; +} + static int lookup_id_by_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr) { @@ -1753,18 +1767,21 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info) return -EOPNOTSUPP; }
- list_for_each_entry(entry, &pernet->local_addr_list, list) { - if ((!lookup_by_id && addresses_equal(&entry->addr, &addr.addr, true)) || - (lookup_by_id && entry->addr.id == addr.addr.id)) { - mptcp_nl_addr_backup(net, &entry->addr, bkup); - - if (bkup) - entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP; - else - entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP; - } + spin_lock_bh(&pernet->lock); + entry = __lookup_addr(pernet, &addr.addr, lookup_by_id); + if (!entry) { + spin_unlock_bh(&pernet->lock); + return -EINVAL; }
+ if (bkup) + entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP; + else + entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP; + addr = *entry; + spin_unlock_bh(&pernet->lock); + + mptcp_nl_addr_backup(net, &addr.addr, bkup); return 0; }