In MP mode, ovpn uses peer VPN addresses as lookup keys for selecting
the peer that should receive outgoing tunnel packets. The netlink
configuration path currently accepts address values that cannot sensibly
identify a VPN peer, such as multicast, broadcast or loopback addresses.
Reject invalid peer VPN addresses when creating or updating an MP peer.
Keep accepting the unspecified address as the internal unset value,
provided that at least one VPN address family remains configured.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
In MP mode, ovpn uses the peer VPN addresses to select the peer for
outgoing tunnel packets. Peer creation currently requires a VPN IPv4 or
IPv6 attribute, but it only checks for the presence of the attribute and
not for a usable address value.
This allows userspace to create an MP peer with only unspecified VPN
addresses, or to update an existing peer so that both VPN address
families become unspecified. Such a peer cannot be selected through the
VPN address hash tables.
Reject MP peer creation or update when the resulting peer would not have
at least one VPN address configured.
This changes such configurations from being accepted to being rejected,
but they have never been usable because the peer cannot be selected
through the VPN address hash tables.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
In MP mode, ovpn uses the peer VPN addresses as lookup keys for
selecting the peer that should receive an outgoing tunnel packet.
However, the netlink peer configuration path does not currently reject
duplicate VPN addresses.
If two peers are configured with the same VPN address, both can be
inserted in the VPN address hash table and lookups return whichever peer
is found first. This makes peer selection ambiguous and dependent on
hash insertion order.
Reject peer creation or update when the resulting VPN address is already
assigned to another peer. Ignore unspecified addresses because those are
not inserted in the VPN address hash tables.
This changes such configurations from being accepted to being rejected,
but they have never worked reliably because peer selection is ambiguous.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_peer_hash_vpn_ip updates the per-peer VPN address hash entries
after userspace changes a peer VPN address. The current code removes an
old hash entry only when the new address for that family is not the
unspecified address.
When an address is cleared to 0.0.0.0 or ::, its hash node therefore
remains linked in the bucket selected by the old address. The address
comparison performed during lookup prevents the old address from
matching, but the table retains a stale entry until the peer is removed
or another address is configured for that family.
Always remove both old VPN address hash entries before conditionally
adding the currently configured addresses back. This ensures that a
cleared address leaves its hash node unhashed.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
The UDP output fallback clears bind->local in place when the remembered
source address is no longer usable. The bind is RCU-published and read
locklessly by concurrent TX, so an IPv6 reader can observe a torn
address.
Retry the route lookup with source address autoselection without
modifying the bind. After a successful lookup, revalidate the bind and
route key under peer->lock, reset the dst cache, and best-effort publish
a replacement bind with a wildcard local address.
Do not cache the resolved dst when clearing the local source. Replacing
the source invalidates all per-CPU cache entries, while
dst_cache_set_ip4 and dst_cache_set_ip6 update only the current CPU
slot. The current packet can still use the resolved route; if bind
allocation fails, a later cache miss retries the repair.
Fixes: 08857b5ec5 ("ovpn: implement basic TX path (UDP)")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
struct ovpn_bind is published through peer->bind with RCU, but local
endpoint learning updates bind->local in place under peer->lock. UDP TX
reads the field without that lock. In particular, a concurrent IPv6
update can therefore result in a torn address read.
Use ovpn_peer_reset_sockaddr to publish a replacement bind when learning
a new local endpoint, just as a remote endpoint change does. Preserve
the current remote address and reset the dst cache only after the new
bind has been published successfully.
Track remote endpoint changes separately so that float notification and
transport-address rehashing remain limited to actual peer floats.
Fixes: f0281c1d37 ("ovpn: add support for updating local or remote UDP endpoint")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
UDP route lookup runs without peer->lock while the bind is protected by
RCU. The route key is snapshotted separately. Either can change while
the lookup is in progress.
The TX path currently checks only the route key before publishing the
looked-up dst. If the bind changes but the route key does not, a dst
resolved from the old endpoint can be installed in the cache after the
bind replacement.
Compare both the bind pointer and the route key under peer->lock before
updating the cache. The RCU read-side critical section keeps the old
bind alive throughout the lookup, so pointer identity is sufficient to
detect a replacement.
Fixes: f0281c1d37 ("ovpn: add support for updating local or remote UDP endpoint")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn stores the route used to transmit UDP packets in a per-peer dst
cache. A cached dst is only valid for the route lookup inputs used when
it was resolved.
Some of those inputs are mutable while userspace still owns the UDP
socket. In particular, changes to the socket mark or UDP source port do
not invalidate ovpn's peer dst cache, so ovpn can keep using a route
selected with an old socket route key.
Replace the cached mark with a route key containing the socket-owned
lookup inputs currently used by ovpn, and reset the peer dst cache when
the key changes. Before storing a newly looked-up dst, recheck the route
key under the peer lock so a dst resolved for stale socket state is not
published.
Fixes: 08857b5ec5 ("ovpn: implement basic TX path (UDP)")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn validates the cached local UDP source address before reusing or
refreshing a peer dst cache. This is only meaningful when a concrete
source address is selected.
For IPv6, calling ipv6_chk_addr with :: checks whether the unspecified
address itself is configured on the host. A peer may legitimately have
bind->local.ipv6 set to :: when no local endpoint was configured or
after a stale learned address was cleared. In that case the source
should be left unspecified and selected by ip6_dst_lookup_flow().
For IPv4, inet_confirm_addr(..., local = 0, ...) asks for local address
autoselection rather than validating a chosen source. Skip the precheck
there as well and let ip_route_output_flow select or reject the source.
Only validate non-zero/non-any source addresses.
Fixes: 08857b5ec5 ("ovpn: implement basic TX path (UDP)")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn accepts OVPN_A_PEER_REMOTE_IPV6_SCOPE_ID and reports
bind->remote.in6.sin6_scope_id in peer dumps, but the netlink endpoint
parser never copied the attribute into the sockaddr_in6 used to create or
update the peer bind.
As a result, an IPv6 link-local remote endpoint configured through
netlink loses its interface scope, unlike on the peer float path where
ipv6_iface_scope_id populates the field. The UDPv6 output path then
builds a flow with flowi6_oif set to zero and route lookup can fail or
select the wrong interface.
Copy the scope id when parsing non-v4-mapped IPv6 remote endpoints. The
existing precheck already rejects the scope-id attribute for IPv4 and
v4-mapped IPv6 remotes.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Key slots are released through a kref and the existing release path
frees the AEAD transforms from an RCU callback. That is not safe for all
crypto implementations: crypto_free_aead can sleep, for example when an
async or hardware implementation has teardown work to complete.
Use queue_rcu_work for key-slot release. This keeps the RCU grace period
needed by lockless key-slot readers, but runs the actual crypto teardown
from workqueue context where sleeping is allowed. Once the rcu_work
callback runs, pre-existing RCU readers are gone, and the final kref put
already proves that no transform user remains, so the worker can release
the AEAD transforms and free the slot directly.
The previous patch drains ovpn_wq during module exit, so queued key-slot
teardown work cannot outlive module text.
Fixes: 8534731dbf ("ovpn: implement packet processing")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn queues several work items whose callbacks execute module text.
These works currently run on the global system workqueues, so module
exit has no driver-owned drain point that guarantees the callbacks have
fully returned before the module text can be freed.
Object references protect the objects used by the callbacks, but they do
not prove that a workqueue function has returned. In particular, a
worker can drop the final reference that unblocks device teardown while
it is still executing ovpn code.
Add a module-owned workqueue and queue all ovpn work items on it. During
module exit, unregister rtnl and netlink first, flush the workqueue so
ordinary ovpn workers finish, run the final RCU barrier, and destroy the
workqueue last. This keeps the workqueue available for cleanup work
queued from RCU callbacks, while ensuring no ovpn work item can outlive
the module text.
The per-device delayed keepalive work remains explicitly disabled during
netdev teardown (disable_delayed_work_sync in ndo_uninit), since
flush_workqueue does not flush delayed work that is still only pending
on its timer.
Fixes: 3ecfd9349f ("ovpn: implement keepalive mechanism")
Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Crypto completion callbacks hold both key-slot and peer references. The
peer reference pins the netdev, and dropping the last peer reference can
let netdev unregistration and module removal make progress.
Do not release that peer reference before the callback has finished its
own cleanup. If ovpn_crypto_key_slot_put runs after ovpn_peer_put, it can
schedule an RCU callback backed by module text after ovpn_cleanup
rcu_barrier has already run. The TX error path also freed the remaining
skb after ovpn_peer_put, leaving callback cleanup outside the peer/netdev
lifetime window.
Release the key slot and free any remaining skb first, then drop the peer
reference as the last callback action.
Fixes: 8534731dbf ("ovpn: implement packet processing")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_crypto_kill_key assumes both crypto slots are populated and
dereferences each slot before checking it. That is not guaranteed: a
peer can have only one installed key, and the kill path may be asked to
remove a key that is not present.
Read each slot once while holding the crypto state lock, check for NULL
before looking at key_id, and only replace the slot that actually
matches.
Fixes: 89d3c0e461 ("ovpn: kill key and notify userspace in case of IV exhaustion")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
rcu_access_pointer() should only be used to test the value of a pointer,
not to dereference it. As it's in a spin_lock_bh() critical section, use
rcu_dereference_bh() instead, avoiding an extra rcu_read_lock().
Fixes: f6226ae7a0 ("ovpn: introduce the ovpn_socket object")
Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Netlink calls may access TCP global vars (i.e. when attaching
a TCP socket), therefore we need to make sure the
latters are initialized beforehand.
For this reason move the global TCP initialization at the top
of the module init function.
Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_mp_alloc() tried to disable SEND_REDIRECTS on a multipeer
interface, but it runs from ovpn_net_init() (->ndo_init), which
register_netdevice() invokes before the NETDEV_REGISTER notifier
chain. The IPv4 in_device is only created when that notifier reaches
inetdev_event() -> inetdev_init(), so __in_dev_get_rtnl() always
returned NULL at ndo_init time and the whole redirect-disabling block
(both the per-device and the per-netns IPV4_DEVCONF_ALL write) was
dead. MP interfaces therefore kept emitting ICMP redirects.
Disabling redirects only once is not enough either: the IPv4
in_device is destroyed and recreated when the interface is moved to a
different network namespace (NETDEV_UNREGISTER/NETDEV_REGISTER), and
the newly created in_device inherits the destination namespace
defaults, silently re-enabling SEND_REDIRECTS.
Disable redirects from ovpn_net_open() (->ndo_open) instead: it runs
every time the interface is brought up, including after the in_device
has been recreated, so the setting is always re-applied. This mirrors
what wireguard does in wg_open(). RTNL is held on the ndo_open() path,
so __in_dev_get_rtnl() is safe.
Fixes: 05003b408c ("ovpn: implement multi-peer support")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
The by_transp_addr table is keyed on the peer's remote transport
address, but the float rehash hashed bind->remote directly, while the
two other sites that touch the table build a clean key first:
ovpn_peer_add_mp() and the lookup in ovpn_peer_get_by_transp_addr()
both hash a sockaddr holding only family/address/port.
For a link-local IPv6 peer, bind->remote carries sin6_scope_id (set
from ipv6_iface_scope_id() when the endpoint is learned), and that
field is folded into the jhash() over sizeof(struct sockaddr_in6).
The lookup never sets sin6_scope_id, so after such a peer floats it is
rehashed into a scope_id-dependent bucket that lookups (scope_id 0)
never visit, making the peer unreachable through the by_transp_addr
fallback. ovpn_peer_transp_match() only compares address and port, so
the hash was keying on a field the match ignores.
sin6_scope_id must stay in bind->remote because the TX path uses it as
flowi6_oif, so it cannot just be cleared there. Instead build the hash
key from family/address/port only, exactly like ovpn_peer_add_mp() and
the lookup, so all three sites agree on the bucket.
Fixes: f0281c1d37 ("ovpn: add support for updating local or remote UDP endpoint")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_peer_endpoints_update() builds the new remote endpoint in an
on-stack struct sockaddr_storage that is left uninitialized. For IPv4
only sin_family/sin_addr/sin_port are written, leaving the 8-byte
sin_zero padding as stack garbage (for IPv6, sin6_flowinfo is left
uninitialized likewise).
ovpn_peer_reset_sockaddr() -> ovpn_bind_from_sockaddr() then memcpy()s
sizeof(struct sockaddr_in)/sizeof(struct sockaddr_in6) bytes - padding
included - into bind->remote. That buffer is later hashed with jhash()
over the same length to place the peer in the by_transp_addr table, so
the garbage padding lands the floated peer in an essentially random
bucket. Lockless lookups in ovpn_peer_get_by_transp_addr() build their
key from a zero-initialized sockaddr_storage, compute a different bucket
and fail to find the peer.
This is also a plain use of uninitialized stack memory in jhash().
Build the floated endpoint with a designated initializer so the
padding (sin_zero for IPv4, sin6_flowinfo for IPv6) is zeroed as part
of the assignment. This keeps the padding out of the by_transp_addr
hash key without memset-ing the whole sockaddr_storage on every
received packet.
Fixes: f0281c1d37 ("ovpn: add support for updating local or remote UDP endpoint")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Some subsystems, like BPF SOCKMAP, set sk_user_data without
actually setting the encap_type.
For this reason, we must make sure that the type is the
one ovpn expects before dereferencing sk_user_data.
Failing to do so may lead to out-of-bounds reads.
Fixes: f6226ae7a0 ("ovpn: introduce the ovpn_socket object")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
When userspace updates a peer's remote endpoint via OVPN_CMD_PEER_SET,
ovpn_nl_peer_modify() installs a new ovpn_bind through
ovpn_peer_reset_sockaddr(), but ovpn_nl_peer_set_doit() only calls
ovpn_peer_hash_vpn_ip() to refresh the VPN-IP hashtables. The peer is
left in the bucket of peers->by_transp_addr corresponding to its old
remote address.
As a consequence, datagrams arriving at the UDP RX path from the newly
configured remote hash to a different slot and the lockless lookup in
ovpn_peer_get_by_transp_addr() (called from ovpn_udp_encap_recv()) does
not find the peer, until either a float event or a peer re-add fixes
the bucket.
Introduce ovpn_peer_hash_transp_addr() (modeled after
ovpn_peer_hash_vpn_ip()) and invoke it from ovpn_nl_peer_set_doit()
whenever the request carried a new remote address. The helper bails
out in P2P mode and on peers without a bind (TCP), and relies on
hlist_nulls_del_init_rcu()'s pprev==NULL short-circuit to handle the
case of an entry not currently linked in the table.
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_nl_peer_set_doit() resolves the target peer via
ovpn_peer_get_by_id() before taking ovpn->lock. In the window between
the lookup (which only takes a refcount) and the subsequent
spin_lock_bh(&ovpn->lock), a concurrent OVPN_CMD_PEER_DEL, keepalive
expiry, or socket teardown can take ovpn->lock first, run
ovpn_peer_remove() to unhash the peer from all four tables (by_id,
by_vpn_addr4/6, by_transp_addr) and release the lock. set_doit then
acquires ovpn->lock and calls ovpn_peer_hash_vpn_ip(), which
re-inserts the now-removed peer back into the rehashing tables.
The same race affects the float path: ovpn_peer_endpoints_update()
holds only a refcount and acquires ovpn->lock very late (after async
AEAD decrypt and a netlink notification), then rehashes the peer
in the by_transp_addr table.
The resurrected peer becomes reachable again from the RX lookup
(ovpn_peer_get_by_transp_addr) and the TX VPN-IP lookup, even though
userspace believes it is gone. Once the data-path refcount drops the
peer is freed via call_rcu while the hash entries embedded in it
remain linked, opening a UAF window.
Bail out of the rehash when hash_entry_id is unhashed, mirroring
the sentinel already used by ovpn_peer_remove() to detect the
already-removed state. The check is safe under ovpn->lock, which
serializes every mutation of hash_entry_id, and is a no-op for the
add path because ovpn_peer_add_mp() inserts hash_entry_id before
calling ovpn_peer_hash_vpn_ip().
Fixes: 1d36a36f6d ("ovpn: implement peer add/get/dump/delete via netlink")
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Large keepalive values can overflow the delayed-work delay on 32-bit
systems, causing the keepalive worker to be repeatedly scheduled.
A correct configuration should not require such large keepalive values,
and an upper limit of one day is already generous and unnecessary in
practice. Limit both the keepalive interval and timeout to 86400 seconds.
Signed-off-by: Marco Baffo <marco@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
ovpn_fill_info emits IFLA_OVPN_MODE inside IFLA_INFO_DATA, but
ovpn_link_ops does not provide a get_size callback. Consequently,
rtnetlink's size estimate for ovpn link messages does not include the
nested mode attribute.
Available skb tailroom may hide this mismatch. When the remaining space
is insufficient, however, ovpn_fill_info returns -EMSGSIZE and message
construction fails.
Add the callback and account for IFLA_OVPN_MODE.
Fixes: c2d950c467 ("ovpn: add basic interface creation/destruction/management routines")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: 3ecfd9349f ("ovpn: implement keepalive mechanism")
Signed-off-by: Marco Baffo <marco@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: 80747caef3 ("ovpn: introduce the ovpn_peer object")
Signed-off-by: Marco Baffo <marco@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: 3ecfd9349f ("ovpn: implement keepalive mechanism")
Cc: stable@vger.kernel.org
Signed-off-by: Shuvam Pandey <shuvampandey1@gmail.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: a6a5e87b3e ("ovpn: avoid sleep in atomic context in TCP RX error path")
Cc: stable@vger.kernel.org
Signed-off-by: Pavitra Jha <jhapavitra98@gmail.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: f6226ae7a0 ("ovpn: introduce the ovpn_socket object")
Signed-off-by: Qing Ming <a0yami@mailbox.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: 11851cbd60 ("ovpn: implement TCP transport")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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 <imv4bel@gmail.com>
Closes: https://lore.kernel.org/netdev/aaVgJ16edTfQkYbx@v4bel/
Suggested-by: Sabrina Dubroca <sd@queasysnail.net>
Fixes: 80747caef3 ("ovpn: introduce the ovpn_peer object")
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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: 11851cbd60 ("ovpn: implement TCP transport")
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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 94560267d6 ("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: 11851cbd60 ("ovpn: implement TCP transport")
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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 <kuniyu@google.com>
Link: https://patch.msgid.link/20260502031401.3557229-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ovpn injects decrypted packets into the netdev RX path through
ovpn_netdev_write() which invokes gro_cells_receive() and
dev_dstats_rx_add().
ovpn_netdev_write() is normally called in softirq context,
however, in case of TCP connections it may also be invoked
process context.
When this happens gro_cells_receive() will throw a warning:
[ 230.183747][ T12] WARNING: net/core/gro_cells.c:30 at gro_cells_receive+0x708/0xaa0, CPU#1: kworker/u16:0/12
and lockdep will also report a potential inconsistent lock state:
WARNING: inconsistent lock state
7.0.0-rc4+ #246 Tainted: G W
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
because attempts to acquire gro_cells->bh_lock by both
contexts may lead to a deadlock.
At the same time, dev_dstats_rx_add() does not expect to race
with a softirq (which may happen when invoked in process context),
because the latter may access its per-cpu state and corrupt
it.
Fix all this by invoking local_bh_disable/enable() around
gro_cells_receive() and dev_dstats_rx_add() to ensure that
bottom halves are always disabled before calling both of
them.
Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
After decapsulating a packet, the skb->mac_header still points to the
outer transport header.
Fix this by calling skb_reset_mac_header() in ovpn_netdev_write() to
ensure the MAC header points to the beginning of
the inner IP/network packet, as expected by the rest of the stack.
Reported-by: Minqiang Chen <ptpt52@gmail.com>
Fixes: 8534731dbf ("ovpn: implement packet processing")
Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
As IPv6 is built-in only, the ipv6_stub infrastructure is no longer
necessary.
Convert all drivers currently utilizing ipv6_stub to make direct
function calls. The fallback functions introduced previously will
prevent linkage errors when CONFIG_IPV6 is disabled.
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Tested-by: Ricardo B. Marlière <rbm@suse.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://patch.msgid.link/20260325120928.15848-7-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently ovpn uses three separate dynamically allocated structures to
set up cryptographic operations for both encryption and decryption. This
adds overhead to performance-critical paths and contribute to memory
fragmentation.
This commit consolidates those allocations into a single temporary blob,
similar to what esp_alloc_tmp() does.
The resulting performance gain is +7.7% and +4.3% for UDP when using AES
and ChaChaPoly respectively, and +4.3% for TCP.
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
In order to support the multipeer architecture, upon connection setup
each side of a tunnel advertises a unique ID that the other side must
include in packets sent to them. Therefore when transmitting a packet, a
peer inserts the recipient's advertised ID for that specific tunnel into
the peer ID field. When receiving a packet, a peer expects to find its
own unique receive ID for that specific tunnel in the peer ID field.
Add support for the TX peer ID and embed it into transmitting packets.
If no TX peer ID is specified, fallback to using the same peer ID both
for RX and TX in order to be compatible with the non-multipeer compliant
peers.
Cc: horms@kernel.org
Cc: donald.hunter@gmail.com
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Send a netlink notification when a client updates its remote UDP
endpoint. The notification includes the new IP address, port, and scope
ID (for IPv6).
Cc: linux-kselftest@vger.kernel.org
Cc: horms@kernel.org
Cc: shuah@kernel.org
Cc: donald.hunter@gmail.com
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Use bitops.h for replay window to simplify code.
Signed-off-by: Qingfang Deng <dqfext@gmail.com>
[antonio@openvpn.net: extended commit message]
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
In ovpn_nl_key_swap_doit, the attributes array used to parse the
OVPN_A_KEYCONF uses OVPN_A_PEER_MAX instead of
OVPN_A_KEYCONF_MAX. Note that this does not cause any bug, since
currently OVPN_A_KEYCONF_MAX < OVPN_A_PEER_MAX.
The wrong constant was introduced by commit 203e2bf559
("ovpn: implement key add/get/del/swap via netlink")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
When processing TCP stream data in ovpn_tcp_recv, we receive large
cloned skbs from __strp_rcv that may contain multiple coalesced packets.
The current implementation has two bugs:
1. Header offset overflow: Using pskb_pull with large offsets on
coalesced skbs causes skb->data - skb->head to exceed the u16 storage
of skb->network_header. This causes skb_reset_network_header to fail
on the inner decapsulated packet, resulting in packet drops.
2. Unaligned protocol headers: Extracting packets from arbitrary
positions within the coalesced TCP stream provides no alignment
guarantees for the packet data causing performance penalties on
architectures without efficient unaligned access. Additionally,
openvpn's 2-byte length prefix on TCP packets causes the subsequent
4-byte opcode and packet ID fields to be inherently misaligned.
Fix both issues by allocating a new skb for each openvpn packet and
using skb_copy_bits to extract only the packet content into the new
buffer, skipping the 2-byte length prefix. Also, check the length before
invoking the function that performs the allocation to avoid creating an
invalid skb.
If the packet has to be forwarded to userspace the 2-byte prefix can be
pushed to the head safely, without misalignment.
As a side effect, this approach also avoids the expensive linearization
that pskb_pull triggers on cloned skbs with page fragments. In testing,
this resulted in TCP throughput improvements of up to 74%.
Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When deleting a peer in case of keepalive expiration, the peer is
removed from the OpenVPN hashtable and is temporary inserted in a
"release list" for further processing.
This happens in:
ovpn_peer_keepalive_work()
unlock_ovpn(release_list)
This processing includes detaching from the socket being used to
talk to this peer, by restoring its original proto and socket
ops/callbacks.
In case of TCP it may happen that, while the peer is sitting in
the release list, userspace decides to close the socket.
This will result in a concurrent execution of:
tcp_close(sk)
__tcp_close(sk)
sock_orphan(sk)
sk_set_socket(sk, NULL)
The last function call will set sk->sk_socket to NULL.
When the releasing routine is resumed, ovpn_tcp_socket_detach()
will attempt to dereference sk->sk_socket to restore its original
ops member. This operation will crash due to sk->sk_socket being NULL.
Fix this race condition by testing-and-accessing
sk->sk_socket atomically under sk->sk_callback_lock.
Link: https://lore.kernel.org/netdev/176996279620.3109699.15382994681575380467@eldamar.lan/
Link: https://github.com/OpenVPN/ovpn-net-next/issues/29
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Fixes: 11851cbd60 ("ovpn: implement TCP transport")
Link: https://patch.msgid.link/20260212213130.11497-1-antonio@openvpn.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
