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authorPaolo Abeni <pabeni@redhat.com>2022-02-18 13:35:41 -0800
committerDavid S. Miller <davem@davemloft.net>2022-02-19 12:28:00 +0000
commit837cf45df163a3780bc04b555700231e95b31dc9 (patch)
treef059a95f02bfad5cb1929eda0a3e26f0aca1bb94 /net/mptcp
parent98247bc16a27cf8ead4c47ce9f15888be85841fc (diff)
downloadlinux-837cf45df163a3780bc04b555700231e95b31dc9.tar.bz2
mptcp: fix race in incoming ADD_ADDR option processing
If an MPTCP endpoint received multiple consecutive incoming ADD_ADDR options, mptcp_pm_add_addr_received() can overwrite the current remote address value after the PM lock is released in mptcp_pm_nl_add_addr_received() and before such address is echoed. Fix the issue caching the remote address value a little earlier and always using the cached value after releasing the PM lock. Fixes: f7efc7771eac ("mptcp: drop argument port from mptcp_pm_announce_addr") Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mptcp')
-rw-r--r--net/mptcp/pm_netlink.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 82f82a513f5b..4b5d795383cd 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -660,6 +660,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
unsigned int add_addr_accept_max;
struct mptcp_addr_info remote;
unsigned int subflows_max;
+ bool reset_port = false;
int i, nr;
add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
@@ -669,15 +670,19 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
msk->pm.add_addr_accepted, add_addr_accept_max,
msk->pm.remote.family);
- if (lookup_subflow_by_daddr(&msk->conn_list, &msk->pm.remote))
+ remote = msk->pm.remote;
+ if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
goto add_addr_echo;
+ /* pick id 0 port, if none is provided the remote address */
+ if (!remote.port) {
+ reset_port = true;
+ remote.port = sk->sk_dport;
+ }
+
/* connect to the specified remote address, using whatever
* local address the routing configuration will pick.
*/
- remote = msk->pm.remote;
- if (!remote.port)
- remote.port = sk->sk_dport;
nr = fill_local_addresses_vec(msk, addrs);
msk->pm.add_addr_accepted++;
@@ -690,8 +695,12 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
__mptcp_subflow_connect(sk, &addrs[i], &remote);
spin_lock_bh(&msk->pm.lock);
+ /* be sure to echo exactly the received address */
+ if (reset_port)
+ remote.port = 0;
+
add_addr_echo:
- mptcp_pm_announce_addr(msk, &msk->pm.remote, true);
+ mptcp_pm_announce_addr(msk, &remote, true);
mptcp_pm_nl_addr_send_ack(msk);
}