From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794049825; b=tyP8AirWL6nsPVc5doNRjD4GKX3rYFirsjVt6ivWM1hYf3qCQVyV28abLZ0fuG3NQuiq E/5EhD/38Nk01SXxNJQrM34TJg5uNd6QDiidQASp5qwjVxegtbJABTqKZhme3UGQo7sdF lbPaXpJ0ggxOjqhIHfbisDk+crPnkNnndIr70u4kOLe3cIiJJ/WMv8ORkgD0uGdP2eEgp NlIeTz9shCAfbZqyo6aNX0+r+lGgdvwRkboHeJ56uktfLdFBbPCH7HeMAYwQaIvt0sgwM j3HP2DQRN+nPhcjrGzm+LRevHSxg1rIYFv7wemKBQoFEQGeE4dmaJnMzQQuIetMtTwA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049825; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=JVL9IwUm/HQVZ6/nFZcF4lLFFKOD6C8glHQD8KQEZMI=; b=uG3QwsFtatg87+XlwaIQKemXgjjomZGdVX8o54FSdVVPprZCC6CGNNbcTFwFkHMCNEi+ yH4gKltsfXYs8Dnyxpb+k3emFJ8V/dNAn9Wjpn0zuHnBx61n3KM7piN8eLjmc7mPE8lZN 1BoOndOqZjF0PlYnbQphq/YQ8Gc6soulZJEKQyH3dXsPwq7Zhn67jxBaAd1B2WpUhsxZi XUqLr2zW9ahYLa+FJR3+wuZGwy/cl4XsXij7VWIk00SGdwnQWmkv1McIOjHtz9mw1OBg5 407dzEtpyOrMg0m6oqhisACKipvlxmokRisaBqEnWNHzvQK33zx6RnZLKgJuhA3AiuA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NO+hVzXa; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9CDF5606A326 for ; Sat, 7 Nov 2026 11:10:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=NO+hVzXa Received: by smtp.kernel.org (Postfix) with ESMTPSA id 159211F008A1; Sat, 7 Nov 2026 11:10:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049825; bh=JVL9IwUm/HQVZ6/nFZcF4lLFFKOD6C8glHQD8KQEZMI=; h=From:To:Cc:Subject:Date; b=NO+hVzXarUw/xqPir81OUykFkoJHnQhTW5dq656BZwUcYtkxJisLRrcDKmfEK2/Ut aK+zMEc+YLZ5u0/Hx9SJ0J/pkSFVCM93hkwLnKLwicPVGSBqC2f3h5om1wcPf8ou5h jiCFqmabLHvDK9SSsqp4AHCK5c2ugZeGWaaYEIzGfN9ErLUpqme4yEXS7dAX9+btcN hdBrek6cLskLTMpbv7Z820ch5sx3e4hCq//nHLi11m/EmSGkjabDnlUf76yk1RbtKw g1Suj3GLcXBV9KYam8ldbltOg/FUPUUoR71SRjFyZSgBobkAWhDY8x0euTUTxfrIG9 //x4qjKU8W9qg== From: Sasha Levin To: qingfang.deng@linux.dev, kuba@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] pppoe: delete session hash entries by pointer match" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:10:23 -0500 Message-ID: <20261107061023-failed-5.15-b5b8c81836e2@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x b5b8c81836e2bec7b444dfa2b14fd14e912e9d63 # git commit -s git send-email --to '' --in-reply-to '20261107061023-failed-5.15-b5b8c81836e2@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From b5b8c81836e2bec7b444dfa2b14fd14e912e9d63 Mon Sep 17 00:00:00 2001 From: Qingfang Deng Date: Tue, 20 Oct 2026 17:21:11 +0800 Subject: [PATCH] pppoe: delete session hash entries by pointer match pppoe_connect() copies the requested PPPoE address to a socket before attempting to insert the socket into the session hash table. If the tuple already exists, __set_item() returns -EALREADY, but the copied address and ifindex remain set on the failed socket. Closing that socket then deletes the existing socket's hash entry through pppoe_release(), preventing it from receiving further session traffic. An unprivileged process in the same network namespace can trigger this through a duplicate connection attempt. To avoid the accidental delete, pass the pppox_sock to __delete_item(), and unlink only an entry whose pointer matches the requested socket. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Qingfang Deng Link: https://patch.msgid.link/20261020092118.47416-1-qingfang.deng@linux.dev Signed-off-by: Jakub Kicinski --- drivers/net/ppp/pppoe.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c index bf7414b46a260..ee0e318d6a2a4 100644 --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -194,18 +194,16 @@ static int __set_item(struct pppoe_net *pn, struct pppox_sock *po) return 0; } -static void __delete_item(struct pppoe_net *pn, __be16 sid, - char *addr, int ifindex) +static void __delete_item(struct pppoe_net *pn, const struct pppox_sock *po) { - int hash = hash_item(sid, addr); + int hash = hash_item(po->pppoe_pa.sid, po->pppoe_pa.remote); struct pppox_sock *ret, __rcu **src; ret = rcu_dereference_protected(pn->hash_table[hash], lockdep_is_held(&pn->hash_lock)); src = &pn->hash_table[hash]; while (ret) { - if (cmp_addr(&ret->pppoe_pa, sid, addr) && - ret->pppoe_ifindex == ifindex) { + if (ret == po) { struct pppox_sock *next; next = rcu_dereference_protected(ret->next, @@ -236,11 +234,10 @@ static inline struct pppox_sock *get_item(struct pppoe_net *pn, __be16 sid, return po; } -static inline void delete_item(struct pppoe_net *pn, __be16 sid, - char *addr, int ifindex) +static void delete_item(struct pppoe_net *pn, const struct pppox_sock *po) { spin_lock(&pn->hash_lock); - __delete_item(pn, sid, addr, ifindex); + __delete_item(pn, po); spin_unlock(&pn->hash_lock); } @@ -570,8 +567,7 @@ static int pppoe_release(struct socket *sock) * protect "po" from concurrent updates * on pppoe_flush_dev */ - delete_item(pn, po->pppoe_pa.sid, po->pppoe_pa.remote, - po->pppoe_ifindex); + delete_item(pn, po); sock_orphan(sk); sock->sk = NULL; @@ -621,8 +617,7 @@ static int pppoe_connect(struct socket *sock, struct sockaddr_unsized *uservaddr if (stage_session(po->pppoe_pa.sid)) { pppox_unbind_sock(sk); pn = pppoe_pernet(sock_net(sk)); - delete_item(pn, po->pppoe_pa.sid, - po->pppoe_pa.remote, po->pppoe_ifindex); + delete_item(pn, po); if (po->pppoe_dev) { dev_put(po->pppoe_dev); po->pppoe_dev = NULL; @@ -672,8 +667,7 @@ static int pppoe_connect(struct socket *sock, struct sockaddr_unsized *uservaddr error = ppp_register_net_channel(dev_net(dev), &po->chan); if (error) { - delete_item(pn, po->pppoe_pa.sid, - po->pppoe_pa.remote, po->pppoe_ifindex); + delete_item(pn, po); goto err_put; } -- 2.53.0