From b52c5103f64ee825996ca1ab8df7283cde8c5f86 Mon Sep 17 00:00:00 2001 From: Qing Ming Date: Sat, 23 May 2026 16:15:43 +0800 Subject: [PATCH 1/6] ovpn: avoid putting unrelated P2P peer on socket release 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 --- drivers/net/ovpn/peer.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index a09d61296425..1844d97154ce 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -1167,7 +1167,6 @@ static void ovpn_peer_release_p2p(struct ovpn_priv *ovpn, struct sock *sk, ovpn_sock = rcu_access_pointer(peer->sock); if (!ovpn_sock || ovpn_sock->sk != sk) { spin_unlock_bh(&ovpn->lock); - ovpn_peer_put(peer); return; } } From 63bbe18fc03062f483c627838a566a707b62da79 Mon Sep 17 00:00:00 2001 From: Pavitra Jha Date: Sat, 23 May 2026 05:02:43 -0400 Subject: [PATCH 2/6] ovpn: fix peer refcount leak in TCP error paths 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 --- drivers/net/ovpn/tcp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ovpn/tcp.c b/drivers/net/ovpn/tcp.c index 433bd07a4f1b..0af14055c39a 100644 --- a/drivers/net/ovpn/tcp.c +++ b/drivers/net/ovpn/tcp.c @@ -151,7 +151,8 @@ static void ovpn_tcp_rcv(struct strparser *strp, struct sk_buff *skb) /* take reference for deferred peer deletion. should never fail */ if (WARN_ON(!ovpn_peer_hold(peer))) goto err_nopeer; - schedule_work(&peer->tcp.defer_del_work); + if (!schedule_work(&peer->tcp.defer_del_work)) + ovpn_peer_put(peer); ovpn_dev_dstats_rx_dropped(peer->ovpn->dev); err_nopeer: kfree_skb(skb); @@ -283,7 +284,8 @@ static void ovpn_tcp_send_sock(struct ovpn_peer *peer, struct sock *sk) * stream therefore we abort the connection */ ovpn_peer_hold(peer); - schedule_work(&peer->tcp.defer_del_work); + if (!schedule_work(&peer->tcp.defer_del_work)) + ovpn_peer_put(peer); /* we bail out immediately and keep tx_in_progress set * to true. This way we prevent more TX attempts From a4710ae2e7e322fdaefb4be8604228279cfaf48c Mon Sep 17 00:00:00 2001 From: Shuvam Pandey Date: Sat, 23 May 2026 20:38:27 +0545 Subject: [PATCH 3/6] ovpn: hold peer before scheduling keepalive work 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 --- drivers/net/ovpn/peer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 1844d97154ce..2b6096d8b1cc 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -1284,8 +1284,10 @@ static time64_t ovpn_peer_keepalive_work_single(struct ovpn_peer *peer, netdev_dbg(peer->ovpn->dev, "sending keepalive to peer %u\n", peer->id); - if (schedule_work(&peer->keepalive_work)) - ovpn_peer_hold(peer); + if (WARN_ON(!ovpn_peer_hold(peer))) + return 0; + if (!schedule_work(&peer->keepalive_work)) + ovpn_peer_put(peer); } if (next_run1 < next_run2) From 0bd9cfebc1c91e1066e56d6261b99691b9df6008 Mon Sep 17 00:00:00 2001 From: longlong yan Date: Wed, 3 Jun 2026 15:27:41 +0800 Subject: [PATCH 4/6] selftests/net: ovpn: fix getaddrinfo memory leak in ovpn_parse_remote() The ovpn_parse_remote() function has two memory management issues: 1. When both 'host' and 'vpnip' are non-NULL, the first getaddrinfo() allocation is leaked because 'result' is overwritten by the second getaddrinfo() call without freeing the first allocation. 2. When both 'host' and 'vpnip' are NULL, 'result' is an uninitialized stack variable passed to freeaddrinfo(), which is undefined behavior. Fix by initializing 'result' to NULL and calling freeaddrinfo() after the first getaddrinfo() result is consumed. Fixes: 959bc330a439 ("testing/selftests: add test tool and scripts for ovpn module") Signed-off-by: longlong yan Signed-off-by: Antonio Quartulli --- tools/testing/selftests/net/ovpn/ovpn-cli.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/ovpn/ovpn-cli.c b/tools/testing/selftests/net/ovpn/ovpn-cli.c index d40953375c86..f4effa7580c0 100644 --- a/tools/testing/selftests/net/ovpn/ovpn-cli.c +++ b/tools/testing/selftests/net/ovpn/ovpn-cli.c @@ -1785,7 +1785,7 @@ static int ovpn_parse_remote(struct ovpn_ctx *ovpn, const char *host, const char *service, const char *vpnip) { int ret; - struct addrinfo *result; + struct addrinfo *result = NULL; struct addrinfo hints = { .ai_family = ovpn->sa_family, .ai_socktype = SOCK_DGRAM, @@ -1809,6 +1809,8 @@ static int ovpn_parse_remote(struct ovpn_ctx *ovpn, const char *host, } memcpy(&ovpn->remote, result->ai_addr, result->ai_addrlen); + freeaddrinfo(result); + result = NULL; } if (vpnip) { From e1ad6fe5db719874efa45b2caf9934552e09fc43 Mon Sep 17 00:00:00 2001 From: Marco Baffo Date: Mon, 8 Jun 2026 16:04:46 +0200 Subject: [PATCH 5/6] ovpn: fix use after free in unlock_ovpn() 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 --- drivers/net/ovpn/peer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 2b6096d8b1cc..8fdbb5050690 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -26,11 +26,12 @@ static void unlock_ovpn(struct ovpn_priv *ovpn, struct llist_head *release_list) __releases(&ovpn->lock) { - struct ovpn_peer *peer; + struct ovpn_peer *peer, *next; spin_unlock_bh(&ovpn->lock); - llist_for_each_entry(peer, release_list->first, release_entry) { + llist_for_each_entry_safe(peer, next, release_list->first, + release_entry) { ovpn_socket_release(peer); ovpn_peer_put(peer); } From f7e6287ccd3abeed9e638b581dc3fdf742106ba3 Mon Sep 17 00:00:00 2001 From: Marco Baffo Date: Mon, 8 Jun 2026 16:06:42 +0200 Subject: [PATCH 6/6] ovpn: use monotonic clock for peer keepalive timeouts 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 --- drivers/net/ovpn/io.c | 4 ++-- drivers/net/ovpn/peer.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c index a6b777a9c2d9..9a66d693039a 100644 --- a/drivers/net/ovpn/io.c +++ b/drivers/net/ovpn/io.c @@ -142,7 +142,7 @@ void ovpn_decrypt_post(void *data, int ret) } /* keep track of last received authenticated packet for keepalive */ - WRITE_ONCE(peer->last_recv, ktime_get_real_seconds()); + WRITE_ONCE(peer->last_recv, ktime_get_boottime_seconds()); rcu_read_lock(); sock = rcu_dereference(peer->sock); @@ -294,7 +294,7 @@ void ovpn_encrypt_post(void *data, int ret) ovpn_peer_stats_increment_tx(&peer->link_stats, orig_len); /* keep track of last sent packet for keepalive */ - WRITE_ONCE(peer->last_sent, ktime_get_real_seconds()); + WRITE_ONCE(peer->last_sent, ktime_get_boottime_seconds()); /* skb passed down the stack - don't free it */ skb = NULL; err_unlock: diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index 8fdbb5050690..a21d02ac715e 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -45,7 +45,7 @@ static void unlock_ovpn(struct ovpn_priv *ovpn, */ void ovpn_peer_keepalive_set(struct ovpn_peer *peer, u32 interval, u32 timeout) { - time64_t now = ktime_get_real_seconds(); + time64_t now = ktime_get_boottime_seconds(); netdev_dbg(peer->ovpn->dev, "scheduling keepalive for peer %u: interval=%u timeout=%u\n", @@ -1359,7 +1359,7 @@ void ovpn_peer_keepalive_work(struct work_struct *work) { struct ovpn_priv *ovpn = container_of(work, struct ovpn_priv, keepalive_work.work); - time64_t next_run = 0, now = ktime_get_real_seconds(); + time64_t next_run = 0, now = ktime_get_boottime_seconds(); LLIST_HEAD(release_list); spin_lock_bh(&ovpn->lock);