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 CBFB34EFFA2; Tue, 13 Oct 2026 12:12:26 +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=1791893549; cv=none; b=BPoBtxdgk2nLJJG/y1i3+aVk2V9xQevO31P9oDKkoItR05W7GSPKDulVhdP0DPJ8sXCyt/Lij7weQGL+NlCMT3tAER1lBTbL4H1ny8B97kvQ7RIA2Hvk5UaUcVSoKXDE/o7FVQ//+ON81vj7sm//DZDSXb2pxgPcXYUOP2+wUOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893549; c=relaxed/simple; bh=XZClN/aktDho0N9BhqcYbPeTVPOlVy2PsEYmWeSmDnU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fTW1O9dDA8e30IasyjshJIkWJSV0RA2/8feL2ogWek/PwZP7PKEJfhePmqGIcTt0T7H0DgEiR2Zpa2yiElGUtsDksBni/m6OrAvrQQG201KFeDMEJaPHrzB9hkXKJs7I33bbc5sTqgZnl5IG1oTDvyHzS9Mq0G0kHcfN5glV3Vo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Rhi/Bd5M; 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="Rhi/Bd5M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AD0B1F000FF; Tue, 13 Oct 2026 12:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893546; bh=Dv3lz4WZ0yhIZWLi5tZ2ahg/qD9D+j04UIiKb6KlCXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Rhi/Bd5Mg13CLhp7FUsM6YgJ1ffd7agSu9uqr2b2/mP7cMbHlvjrjtnmR831AAil3 dJ7eZiiSofHlwE3vPCt7Mi/GRsI+VatfT0SMyhsQhZttMPdKdrdsZDTA7zc8oZQelv NfyDrEEsECGMh5/+sF6DCh9cx5TjlhHB3/moFrds= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Tung Nguyen , Weiming Shi , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 263/621] tipc: serialize udp bearer replicast list updates Date: Tue, 13 Oct 2026 13:34:18 +0200 Message-ID: <20261013112927.100783997@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@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: Weiming Shi [ Upstream commit 350e592ff4e30e48ffb55e142d11a73e63f4869c ] tipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with list_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs from the encap receive softirq (via tipc_udp_rcast_disc()) without rtnl_lock(), so it can race the cleanup delete and corrupt the list: list_del corruption. prev->next should be ffff8880298d7ab8, but was ffff88802449ad38. (prev=ffff888027e3ec98) kernel BUG at lib/list_debug.c:62! RIP: __list_del_entry_valid_or_report+0x17a/0x200 Workqueue: events cleanup_bearer Call Trace: cleanup_bearer (net/tipc/udp_media.c:811) process_one_work (kernel/workqueue.c:3302) worker_thread (kernel/workqueue.c:3466) The bearer can be enabled from an unprivileged user namespace, as the TIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM. Add a spinlock to struct udp_bearer and take it around the list_add_rcu() in tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so the two writers can no longer corrupt the list. Reject a duplicate peer under the same lock before allocating, and remove tipc_udp_is_known_peer(). The old lockless pre-check in tipc_udp_rcast_disc() was racy: two softirqs discovering the same peer could both find it absent and add it twice. cleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the bearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add() and add a peer after cleanup_bearer() has already emptied the list, leaking that entry when the bearer is freed. Mark the bearer disabled under rcast_lock once the list is emptied and refuse further additions. Fixes: ef20cd4dd163 ("tipc: introduce UDP replicast") Reported-by: Xiang Mei Suggested-by: Tung Nguyen Signed-off-by: Weiming Shi Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260716025203.9332-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/tipc/udp_media.c | 56 +++++++++++++++++++++----------------------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index b85ab0fb3b8cc..4a1b73a1943dd 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -94,6 +94,8 @@ struct udp_replicast { * @ifindex: local address scope * @work: used to schedule deferred work on a bearer * @rcast: associated udp_replicast container + * @rcast_lock: serialize updates to @rcast.list against concurrent updaters + * @disabled: bearer is being torn down; reject further @rcast.list additions */ struct udp_bearer { struct tipc_bearer __rcu *bearer; @@ -101,6 +103,8 @@ struct udp_bearer { u32 ifindex; struct work_struct work; struct udp_replicast rcast; + spinlock_t rcast_lock; + bool disabled; }; static int tipc_udp_is_mcast_addr(struct udp_media_addr *addr) @@ -279,26 +283,6 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb, return err; } -static bool tipc_udp_is_known_peer(struct tipc_bearer *b, - struct udp_media_addr *addr) -{ - struct udp_replicast *rcast, *tmp; - struct udp_bearer *ub; - - ub = rcu_dereference_rtnl(b->media_ptr); - if (!ub) { - pr_err_ratelimited("UDP bearer instance not found\n"); - return false; - } - - list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) { - if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr))) - return true; - } - - return false; -} - static int tipc_udp_rcast_add(struct tipc_bearer *b, struct udp_media_addr *addr) { @@ -309,16 +293,34 @@ static int tipc_udp_rcast_add(struct tipc_bearer *b, if (!ub) return -ENODEV; + spin_lock_bh(&ub->rcast_lock); + if (ub->disabled) { + spin_unlock_bh(&ub->rcast_lock); + return 0; + } + list_for_each_entry(rcast, &ub->rcast.list, list) { + if (!memcmp(&rcast->addr, addr, sizeof(*addr))) { + spin_unlock_bh(&ub->rcast_lock); + return 0; + } + } + rcast = kmalloc(sizeof(*rcast), GFP_ATOMIC); - if (!rcast) + if (!rcast) { + spin_unlock_bh(&ub->rcast_lock); return -ENOMEM; + } if (dst_cache_init(&rcast->dst_cache, GFP_ATOMIC)) { + spin_unlock_bh(&ub->rcast_lock); kfree(rcast); return -ENOMEM; } memcpy(&rcast->addr, addr, sizeof(struct udp_media_addr)); + list_add_rcu(&rcast->list, &ub->rcast.list); + b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT; + spin_unlock_bh(&ub->rcast_lock); if (ntohs(addr->proto) == ETH_P_IP) pr_info("New replicast peer: %pI4\n", &rcast->addr.ipv4); @@ -326,8 +328,6 @@ static int tipc_udp_rcast_add(struct tipc_bearer *b, else if (ntohs(addr->proto) == ETH_P_IPV6) pr_info("New replicast peer: %pI6\n", &rcast->addr.ipv6); #endif - b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT; - list_add_rcu(&rcast->list, &ub->rcast.list); return 0; } @@ -362,9 +362,6 @@ static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb) return 0; } - if (likely(tipc_udp_is_known_peer(b, &src))) - return 0; - return tipc_udp_rcast_add(b, &src); } @@ -646,9 +643,6 @@ int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr) return -EINVAL; } - if (tipc_udp_is_known_peer(b, &addr)) - return 0; - return tipc_udp_rcast_add(b, &addr); } @@ -680,6 +674,7 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b, return -ENOMEM; INIT_LIST_HEAD(&ub->rcast.list); + spin_lock_init(&ub->rcast_lock); if (!attrs[TIPC_NLA_BEARER_UDP_OPTS]) goto err; @@ -809,11 +804,14 @@ static void cleanup_bearer(struct work_struct *work) struct udp_replicast *rcast, *tmp; struct tipc_net *tn; + spin_lock_bh(&ub->rcast_lock); list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) { dst_cache_destroy(&rcast->dst_cache); list_del_rcu(&rcast->list); kfree_rcu(rcast, rcu); } + ub->disabled = true; + spin_unlock_bh(&ub->rcast_lock); tn = tipc_net(sock_net(ub->ubsock->sk)); -- 2.53.0