From: Paolo Abeni <pabeni@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
}
--
2.34.1
