kernel/linux.git/drivers/net/ovpn, branch v7.1.6

ovpn: hold peer before scheduling keepalive work

2026-08-03T09:26:00+00:00

commit a4710ae2e7e322fdaefb4be8604228279cfaf48c upstream. ovpn_peer_keepalive_send() passes its peer reference to ovpn_xmit_special(), which ultimately drops it. The keepalive scheduler currently queues the work first and takes the reference only after schedule_work() reports that the work was queued. Once schedule_work() queues the item, another CPU may run the worker before the caller gets to ovpn_peer_hold(). In that case the worker can consume a reference that was not acquired for it, corrupting the peer lifetime accounting. Take the peer reference before queueing the work and drop it again when the work was already pending. Fixes: 3ecfd9349f40 ("ovpn: implement keepalive mechanism") Cc: stable@vger.kernel.org Signed-off-by: Shuvam Pandey Reviewed-by: Sabrina Dubroca Signed-off-by: Antonio Quartulli Signed-off-by: Greg Kroah-Hartman

ovpn: fix peer refcount leak in TCP error paths

2026-08-03T09:26:00+00:00

commit 63bbe18fc03062f483c627838a566a707b62da79 upstream. When either the TCP RX or TX error path calls ovpn_peer_hold() followed by schedule_work(&peer->tcp.defer_del_work), and the work item is already pending from the other path, schedule_work() returns false and the work runs only once. Since ovpn_tcp_peer_del_work() calls ovpn_peer_put() exactly once, the extra reference taken by the losing path is never dropped, leaking the peer object. The race window: CPU0 (strparser/RX error): CPU1 (tcp_tx_work/TX error): ovpn_peer_hold() <- refcnt+1 ovpn_peer_hold() <- refcnt+2 schedule_work() <- queued schedule_work() <- NO-OP (work already pending) ovpn_tcp_peer_del_work runs: ovpn_peer_del() ovpn_peer_put() <- refcnt+1 <- peer never freed Fix by checking the return value of schedule_work() in both paths and calling ovpn_peer_put() to drop the extra reference if the work was already pending. ovpn_peer_hold() is kept unconditional in the TX path as it cannot fail at that point. Fixes: a6a5e87b3ee4 ("ovpn: avoid sleep in atomic context in TCP RX error path") Cc: stable@vger.kernel.org Signed-off-by: Pavitra Jha Reviewed-by: Sabrina Dubroca Signed-off-by: Antonio Quartulli Signed-off-by: Greg Kroah-Hartman

ovpn: use monotonic clock for peer keepalive timeouts

2026-08-03T09:25:30+00:00

[ Upstream commit f7e6287ccd3abeed9e638b581dc3fdf742106ba3 ] Replace ktime_get_real_seconds() with the monotonic ktime_get_boottime_seconds() to ensure the keepalive mechanism is robust against system clock modifications. Right now, the driver uses ktime_get_real_seconds() to track peer timeouts, relying on the system wall-clock. An administrative time adjustment or an NTP sync that steps the clock forward can cause `now' to instantly exceed `last_recv + timeout'. When this occurs, the driver artificially expires healthy peers. Depending on the OpenVPN user-space configuration, this triggers a premature tunnel restart (if --keepalive or --ping-restart is used) or a complete disconnection of the client (if --ping-exit is used). Fixes: 3ecfd9349f40 ("ovpn: implement keepalive mechanism") Signed-off-by: Marco Baffo Signed-off-by: Antonio Quartulli Signed-off-by: Sasha Levin

ovpn: fix use after free in unlock_ovpn()

2026-08-03T09:25:29+00:00

[ Upstream commit e1ad6fe5db719874efa45b2caf9934552e09fc43 ] unlock_ovpn() iterates over the release_list using llist_for_each_entry() and drops the peer reference inside the loop body via ovpn_peer_put(). If this drops the last reference, the peer is eventually freed. However, llist_for_each_entry() reads peer->release_entry.next in the loop advance expression, which runs after the body. By that time the peer may have already been freed, resulting in a use after free when advancing to the next list entry. Fix this by using llist_for_each_entry_safe(), which caches the next pointer before executing the loop body. Fixes: 80747caef33d ("ovpn: introduce the ovpn_peer object") Signed-off-by: Marco Baffo Signed-off-by: Antonio Quartulli Signed-off-by: Sasha Levin

ovpn: avoid putting unrelated P2P peer on socket release

2026-08-03T09:25:29+00:00

[ Upstream commit b52c5103f64ee825996ca1ab8df7283cde8c5f86 ] ovpn_peer_release_p2p() is called when an OVPN UDP socket is being destroyed. It checks the currently published P2P peer and releases it only if that peer still uses the socket being destroyed. A peer replacement can publish a new peer before the old UDP socket is destroyed. When the old socket destruction path runs afterwards, ovpn_peer_release_p2p() observes the new peer through ovpn->peer. Since the new peer uses a different socket, the function takes the socket mismatch branch. That branch still calls ovpn_peer_put(peer). At this point, however, peer is the currently published replacement peer, not the peer associated with the socket being destroyed. Dropping its reference can free it while ovpn->peer still points to it, leading to later use-after-free accesses from the peer and socket cleanup paths. KASAN reports this as a slab-use-after-free on the kmalloc-1k ovpn_peer object. In the reproducer, the object is allocated from ovpn_peer_new() via ovpn_nl_peer_new_doit(), and freed through ovpn_peer_release_rcu() from RCU callback processing. Observed access sites include ovpn_peer_remove(), ovpn_socket_release(), ovpn_nl_peer_del_notify(), and unlock_ovpn(). Fix this by returning from the socket mismatch branch without putting the peer. Fixes: f6226ae7a0cd ("ovpn: introduce the ovpn_socket object") Signed-off-by: Qing Ming Reviewed-by: Simon Horman Signed-off-by: Antonio Quartulli Signed-off-by: Sasha Levin

udp_tunnel: Pass struct sock to setup_udp_tunnel_sock().

2026-07-24T14:20:31+00:00

[ Upstream commit 2cba193628fe523cee6dd61938db2c4563ce15a9 ] None of the udp_tunnel users need struct socket in their fast paths; it is only used for tunnel setup / teardown. Even setup_udp_tunnel_sock() does not need struct socket. Let's change setup_udp_tunnel_sock() to take struct sock instead of struct socket. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260502031401.3557229-3-kuniyu@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: c1481c94e74c ("tipc: avoid busy looping in tipc_exit_net()") Signed-off-by: Sasha Levin

ovpn: disable BHs when updating device stats

2026-05-14T22:43:55+00:00

ovpn updates dev->dstats from both process and softirq contexts. In particular, TCP paths may run from socket callbacks, workqueues or strparser work, while UDP receive and ovpn's ndo_start_xmit path may update the same per-device dstats from BH context. Add ovpn device drop-stat helpers that disable BHs around dev_dstats_rx_dropped() and dev_dstats_tx_dropped(), and use them for drop accounting. The successful RX dev_dstats_rx_add() update is already covered by the BH-disabled section around gro_cells_receive(). For the successful TCP TX dev_dstats_tx_add() update, replace the existing preempt-disabled section with a BH-disabled one. Fixes: 11851cbd60ea ("ovpn: implement TCP transport") Signed-off-by: Ralf Lici Signed-off-by: Antonio Quartulli

ovpn: fix race between deleting interface and adding new peer

2026-05-14T14:24:45+00:00

While deleting an existing ovpn interface, there is a very narrow window where adding a new peer via netlink may cause the netdevice to hang and prevent its unregistration. It may happen during ovpn_dellink(), when all existing peers are freed and the device is queued for deregistration, but a CMD_PEER_NEW message comes in adding a new peer that takes again a reference to the netdev. At this point there is no way to release the device because we are under the assumption that all peers were already released. Fix the race condition by releasing all peers in ndo_uninit(), when the netdevice has already been removed from the netdev list. Also ovpn_peer_add() has now an extra check that forces the function to bail out if the device reg_state is not REGISTERED. This way any incoming CMD_PEER_NEW racing with the interface deletion routine will simply stop before adding the peer. Note that the above check happens while holding the netdev_lock to prevent racing netdev state changes. ovpn_dellink() is now empty and can be removed. Reported-by: Hyunwoo Kim Closes: https://lore.kernel.org/netdev/aaVgJ16edTfQkYbx@v4bel/ Suggested-by: Sabrina Dubroca Fixes: 80747caef33d ("ovpn: introduce the ovpn_peer object") Reviewed-by: Sabrina Dubroca Signed-off-by: Antonio Quartulli

ovpn: respect peer refcount in CMD_NEW_PEER error path

2026-05-14T14:24:45+00:00

ovpn_nl_peer_new_doit()'s error path calls ovpn_peer_release() directly rather than ovpn_peer_put(), bypassing the kref. The accompanying comment ("peer was not yet hashed, thus it is not used in any context") holds for UDP but not for TCP. For UDP, the ovpn_socket union uses the .ovpn arm and never points back at a peer; UDP encap_recv looks up peers via the not-yet-populated hashtables, so the new peer is unreachable until ovpn_peer_add() publishes it. For TCP, ovpn_socket_new() sets ovpn_sock->peer and ovpn_tcp_socket_attach() publishes ovpn_sock via rcu_assign_sk_user_data(). From that moment until ovpn_socket_release() detaches in the error path, the TCP fd is fully wired: userspace recvmsg / sendmsg / close / poll on the fd, as well as the strparser-driven ovpn_tcp_rcv() path, can reach the peer through sk_user_data -> ovpn_sock->peer and bump its refcount via ovpn_peer_hold(). ovpn_tcp_socket_wait_finish() (called inside ovpn_socket_release()) drains strparser and the tx work, but does not synchronize with userspace syscall callers that already hold a peer reference. If ovpn_nl_peer_modify() or ovpn_peer_add() returns an error while such a caller is in flight - notably an ovpn_tcp_recvmsg() blocked in __skb_recv_datagram() on peer->tcp.user_queue - the direct ovpn_peer_release() destroys the peer while the caller still holds the reference, and the eventual ovpn_peer_put() from that caller operates on freed memory. Replace the direct destructor call with ovpn_peer_put() so the kref correctly defers destruction until the last reference is dropped. In the common case where no concurrent user is present, behaviour is unchanged: the kref hits zero immediately and ovpn_peer_release_kref() runs the same destructor. With this conversion ovpn_peer_release() has no callers outside peer.c - ovpn_peer_release_kref() in the same translation unit is the only remaining user - so make it static and drop its declaration from peer.h. Fixes: 11851cbd60ea ("ovpn: implement TCP transport") Reviewed-by: Sabrina Dubroca Assisted-by: Claude:claude-opus-4-7 Signed-off-by: David Carlier Signed-off-by: Antonio Quartulli

ovpn: tcp - use cached peer pointer in ovpn_tcp_close()

2026-05-14T14:24:45+00:00

ovpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data() under rcu_read_lock(), takes a reference on sock->peer, caches the peer pointer in a local, and drops the read lock. It then passes sock->peer (rather than the cached local) to ovpn_peer_del(), re-dereferencing the ovpn_socket after the RCU read section has ended. Unlike ovpn_tcp_sendmsg(), which uses the same "load under RCU, use after unlock" pattern but is protected by lock_sock() held across the function, ovpn_tcp_close() runs without the socket lock: inet_release() invokes sk_prot->close() without taking lock_sock first. ovpn_socket_release() can therefore complete its kref_put -> detach -> synchronize_rcu -> kfree(sock) sequence concurrently, in the window after ovpn_tcp_close() drops rcu_read_lock() but before it dereferences sock->peer. The synchronize_rcu() in ovpn_socket_release() protects readers that use the dereferenced pointer inside the RCU read section, not those that escape the pointer to a local and use it afterwards. A reproducer follows the pattern of commit 94560267d6c4 ("ovpn: tcp - don't deref NULL sk_socket member after tcp_close()"): trigger a peer removal (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same moment userspace closes the TCP fd. That commit fixed the detach-side of the same race window; this one fixes the close-side at a different victim. Tighten the entry block to read sock->peer exactly once into the cached peer local, and route all subsequent uses (the hold check, the ovpn_peer_del() call, and the prot->close() invocation) through that local. sock->peer is only ever written once in ovpn_socket_new() under lock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket, and is never reassigned afterwards - but the previous multi-read pattern made that invariant implicit rather than explicit. The same multi-read shape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(), ovpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned up via a dedicated helper in a follow-up net-next series. Fixes: 11851cbd60ea ("ovpn: implement TCP transport") Reviewed-by: Sabrina Dubroca Assisted-by: Claude:claude-opus-4-7 Signed-off-by: David Carlier Signed-off-by: Antonio Quartulli