From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DAEE23AEF2E; Wed, 30 Sep 2026 18:30:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790793009; cv=none; b=ck1QbIDFFT6jqw1bHBEtSnt6pTIDBL0ILv1iCS9oMvVeNObpZXB6c3Wmz7KRVX1W1HO0mbZ3ncQIKr18WYry7dRQX+c5NaBEd9RPHcaAURxUYs1cftsorJWeqCADt0R9/pNbWBaew39KPL+2ho6YKK/nSVZA/eIOrKz0SkhF3TU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790793009; c=relaxed/simple; bh=xtoqGBFKniLFnaAydSmsE6tq9WIWFXSYFRs7xQvwDsg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VBKa2/zXb2a3ZgNedrQc4bJcLIDJVqYil8yjmvIgQ3iB9czajaBuv9e/mKyIcKl8Nikfjme5Ernn/3YsvM+k4EW6tOv8qLL3q2ocoeQNALPUmOBGt4IhRcBPXrKblZktbqK4pbPGKqfR9A3lXhhaJ3+HjZI3n9TID1rbMoAi788= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ldL+sOug; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ldL+sOug" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 449BC1F000FF; Wed, 30 Sep 2026 18:30:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790793007; bh=bVtdepO+CsWv9P4bIGMRPusiV+GUZ+yZghyueoF/Weg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ldL+sOugnhAI9le5BOKjsqHsTu2YCVU6GBq8bPMxjxvazV4kzjBsheceo5dRpk/rQ lHuvqaACukrX3+yFQLSO1X2ehJSIeLYqo0PiPvXvcJLqxG1tbQclU+c9dwLmZ6+MJp m8dpB6t2AzuggULYctTY6Tpjcbe01Ay9P0kIPzL0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ralf Lici , Antonio Quartulli , Sasha Levin Subject: [PATCH 6.18 103/395] ovpn: replace bind when clearing stale local source Date: Wed, 30 Sep 2026 17:26:05 +0200 Message-ID: <20260930152342.870067526@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152340.591469096@linuxfoundation.org> References: <20260930152340.591469096@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ralf Lici [ Upstream commit 7d8104988f423572df1f3347ce578037b1043f34 ] 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: 08857b5ec5d9 ("ovpn: implement basic TX path (UDP)") Signed-off-by: Ralf Lici Signed-off-by: Antonio Quartulli Signed-off-by: Sasha Levin --- drivers/net/ovpn/udp.c | 81 +++++++++++++++++++++++++++++------------- 1 file changed, 56 insertions(+), 25 deletions(-) diff --git a/drivers/net/ovpn/udp.c b/drivers/net/ovpn/udp.c index 6ca482144dc4f..0b620c6cc64dd 100644 --- a/drivers/net/ovpn/udp.c +++ b/drivers/net/ovpn/udp.c @@ -186,7 +186,7 @@ static void ovpn_dst_cache_check_key(struct ovpn_peer *peer, * to detect whether the bind was replaced while the route lookup was running. * * Return: true if the lookup result still matches the current peer state and - * may update the dst cache. + * may update the dst cache or replace the bind. */ static bool ovpn_dst_cache_current(const struct ovpn_peer *peer, const struct ovpn_bind *bind, @@ -219,6 +219,9 @@ static int ovpn_udp4_output(struct ovpn_peer *peer, struct ovpn_bind *bind, struct sk_buff *skb, const struct ovpn_route_key *key) { + struct sockaddr_storage remote; + struct in_addr local = {}; + bool reset_local = false; struct rtable *rt; struct flowi4 fl = { .saddr = bind->local.ipv4.s_addr, @@ -237,24 +240,17 @@ static int ovpn_udp4_output(struct ovpn_peer *peer, struct ovpn_bind *bind, if (fl.saddr && unlikely(!inet_confirm_addr(sock_net(sk), NULL, 0, fl.saddr, RT_SCOPE_HOST))) { - /* we may end up here when the cached address is not usable - * anymore. In this case we reset address/cache and perform a - * new look up + /* The learned local address is not usable anymore. + * Retry with source address autoselection. */ fl.saddr = 0; - spin_lock_bh(&peer->lock); - bind->local.ipv4.s_addr = 0; - spin_unlock_bh(&peer->lock); - dst_cache_reset(cache); + reset_local = true; } rt = ip_route_output_flow(sock_net(sk), &fl, sk); if (IS_ERR(rt) && PTR_ERR(rt) == -EINVAL) { fl.saddr = 0; - spin_lock_bh(&peer->lock); - bind->local.ipv4.s_addr = 0; - spin_unlock_bh(&peer->lock); - dst_cache_reset(cache); + reset_local = true; rt = ip_route_output_flow(sock_net(sk), &fl, sk); } @@ -268,10 +264,28 @@ static int ovpn_udp4_output(struct ovpn_peer *peer, struct ovpn_bind *bind, goto err; } - /* avoid storing a stale cache */ + /* avoid storing a stale cache or local address */ spin_lock_bh(&peer->lock); - if (likely(ovpn_dst_cache_current(peer, bind, key))) - dst_cache_set_ip4(cache, &rt->dst, fl.saddr); + if (likely(ovpn_dst_cache_current(peer, bind, key))) { + if (!reset_local) { + dst_cache_set_ip4(cache, &rt->dst, fl.saddr); + spin_unlock_bh(&peer->lock); + goto transmit; + } + + /* invalidate per-CPU dst entries that may still carry + * the stale source + */ + dst_cache_reset(cache); + + /* preserve the current remote */ + memcpy(&remote, &bind->remote, sizeof(struct sockaddr_in)); + /* The current packet already has a valid wildcard-source route. + * If replacing the bind fails, leave the stale local in place; + * a later cache miss will retry the repair. + */ + ovpn_peer_reset_sockaddr(peer, &remote, &local); + } spin_unlock_bh(&peer->lock); transmit: @@ -301,6 +315,9 @@ static int ovpn_udp6_output(struct ovpn_peer *peer, struct ovpn_bind *bind, struct sk_buff *skb, const struct ovpn_route_key *key) { + struct in6_addr local = in6addr_any; + struct sockaddr_storage remote; + bool reset_local = false; struct dst_entry *dst; int ret; @@ -321,15 +338,11 @@ static int ovpn_udp6_output(struct ovpn_peer *peer, struct ovpn_bind *bind, if (!ipv6_addr_any(&fl.saddr) && unlikely(!ipv6_chk_addr(sock_net(sk), &fl.saddr, NULL, 0))) { - /* we may end up here when the cached address is not usable - * anymore. In this case we reset address/cache and perform a - * new look up + /* The learned local address is not usable anymore. + * Retry with source address autoselection. */ fl.saddr = in6addr_any; - spin_lock_bh(&peer->lock); - bind->local.ipv6 = in6addr_any; - spin_unlock_bh(&peer->lock); - dst_cache_reset(cache); + reset_local = true; } dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sk), sk, &fl, NULL); @@ -341,10 +354,28 @@ static int ovpn_udp6_output(struct ovpn_peer *peer, struct ovpn_bind *bind, goto err; } - /* avoid storing a stale cache */ + /* avoid storing a stale cache or local address */ spin_lock_bh(&peer->lock); - if (likely(ovpn_dst_cache_current(peer, bind, key))) - dst_cache_set_ip6(cache, dst, &fl.saddr); + if (likely(ovpn_dst_cache_current(peer, bind, key))) { + if (!reset_local) { + dst_cache_set_ip6(cache, dst, &fl.saddr); + spin_unlock_bh(&peer->lock); + goto transmit; + } + + /* invalidate per-CPU dst entries that may still carry + * the stale source + */ + dst_cache_reset(cache); + + /* preserve the current remote */ + memcpy(&remote, &bind->remote, sizeof(struct sockaddr_in6)); + /* The current packet already has a valid wildcard-source route. + * If replacing the bind fails, leave the stale local in place; + * a later cache miss will retry the repair. + */ + ovpn_peer_reset_sockaddr(peer, &remote, &local); + } spin_unlock_bh(&peer->lock); transmit: -- 2.53.0