From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E0EE412C02 for ; Tue, 14 Jul 2026 17:41:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784050887; cv=none; b=hd6b5jBsimVYaqE1DbwNrAjkaktboAlGGXq5c3a+3NPzx1BZUBDAASsivH0QE05ugt/8cSzyUA0YKb8b/pTWFzMMiseEa14DM9a97CyCkqsWTPNjAt/MSKsZUO0RWeHuVc+o2vxs8lxWULS9RG9KHzzEapF6aiHdEHtOO9aE8jw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784050887; c=relaxed/simple; bh=Ox4/W8NtFAMX+f40X+2E9Ck7CpfewVytyBCKoigiegA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Kwk5GUMi3HaOwm0Z96tyltIeq3jOGsp5KH2E0UouqPx5nyx2TrH5fVNsv2aNbr7/rB00+zDA0hWTae81OR3r38421O94wxzWfjvNA0y+Ms0ExSpy834/85sVGGp5H7XZ32qdTisYy+Fy1rn6Au/ACT59ScINEcpkpYvQQUN0cnc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=g2SiHA7E; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="g2SiHA7E" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2caced6038eso17853655ad.0 for ; Tue, 14 Jul 2026 10:41:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784050883; x=1784655683; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=v+beJDAg7FygtSf3CwSH4de8wcnddt96Jva8qhSMu00=; b=g2SiHA7E9xDKUENAvAE3XoG+lK6jWwa1ad27j46rJ2LlORDaVEzHMtsFzW/2rVZiCk bYbz7WmFglee1V3sB8Tuouce7dz6nOR5O1hyqK3SWIwUNxX4qXLCHv6+Eaax/fffEY4t fIfZ5w6WRAeqxUxwCZC7+BSXdWDcbq1kXvGbX7mpiKitq8X/cnXgeIjBnFhPYKbNpjg8 3HXJuY+udvq2EGbhj1i6RA9HiQnDycnqcO1DTIKIMDLqja5v3hoqusfzSux6jUygdwQh CmYoh7yHdgcbMhlfl2ZYMHoGcycTYevKYeouHdDmnpDUjvqkEq4jDajlCuDZ71wLCNT0 QZGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784050883; x=1784655683; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=v+beJDAg7FygtSf3CwSH4de8wcnddt96Jva8qhSMu00=; b=m24TdKt0oL0Pzx34Xb3b8FcG3mB5omzgOiYLWaLUBIlcctFL6iAxtFuC/BidLLgfsa 2vaLK3dZNLkHARC/fRCk70Cy4ZTt6y3lVHxw36YBwW7l14hupVj7US5X03ew7ccSwUSU H7P88c77vNcSdeONdb3tm6dM5ZONYTOLPnfLv1Ga/7ZtqcEIlngre2NqrI3R3og3M21h NE0DKDDL//41qGU97svC0oaASY38agkSmbzMwXbuaqRegBequenZpd0XOUU4j6uMhFNz CyDY3WAdlzJteVjo0xpsgBol7qRrCLXOKtxk5Mg2qSH1nVx+UDRQPG5RjyhMMdVoIatL q6Ig== X-Forwarded-Encrypted: i=1; AHgh+Rrkac4mrNkUuULNU+d1a6dhetJJacp/pS5RjYZKwQVg45bga1YjCJxOlb3BboPSl52oJ/rK6mY=@vger.kernel.org X-Gm-Message-State: AOJu0Yzt+zaDfVfYpjxW15BYf+2szsKczESy3gdXw02xRt5zJTN2/f/D gQhzGo5IRUXuu9Et6JCsIRItVUyV1aGKyhJSlgS9DeM5lswBmBabRQmA X-Gm-Gg: AfdE7cnMKXNT16FyHkD7nL8XDvxOEt/ly3cVdomVUv5Tk60wrHGIHttItl/sVgURauQ oGkwuujQGhRv84oGOn8xPYHh1uaExvl4Lg0/o3HDgt+Z60n3FGZo+QBr8DY5cuw8MFfcZkg4gzD Qna+UABVHcnMqmffJ2R8br7ZGGR179H/MM/K0Yyu5FWt9QpQUWQbaJL02XDhZG8iMZ51SQQ4qVd dE/ydEzxJ6rAws2AQyrR5g66qDi/h71Dt0RiYpLGIzcb00Yy3g1YHI1ULWfvnTuMCEHB4GJlq+P AhpSLTdvcZfeNpqfDK+gRBRPFGo+v3NT0sjSRddm155Jmnzwuuoa/EH5CnYBefRYeQwfNbmTWS1 ap5SemieagOrz8NNGk+VBhnUlFWcSomCZ+xhHlV09Q1cnnMZjBBwjENAq7kELEcUSSTIgdEVrJY Nn4+zJNMD9KJrxVfa/Jbe0SvGlBgHZObQ92bu4dX3nVmBydr/Okci88E7s+Q== X-Received: by 2002:a17:903:110f:b0:2cc:92ae:b36 with SMTP id d9443c01a7336-2ce82970406mr171900695ad.24.1784050882693; Tue, 14 Jul 2026 10:41:22 -0700 (PDT) Received: from fx.tailc0aff1.ts.net ([206.206.192.132]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13b87b92b27sm38055954c88.6.2026.07.14.10.41.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2026 10:41:21 -0700 (PDT) From: Weiming Shi To: Jon Maloy , netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net Cc: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Hoang Huu Le , Xiang Mei , Tung Quang Nguyen , linux-kernel@vger.kernel.org, Weiming Shi Subject: [PATCH net v3 2/2] tipc: fix NULL deref in tipc_named_node_up() on empty publication list Date: Tue, 14 Jul 2026 10:41:10 -0700 Message-ID: <20260714174110.1571033-3-bestswngs@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260714174110.1571033-1-bestswngs@gmail.com> References: <20260714174110.1571033-1-bestswngs@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit named_distribute() ends by stamping the last_bulk flag on the tail skb via buf_msg(skb_peek_tail(list)). When the publication list is empty no skb is enqueued, skb_peek_tail() returns NULL, and buf_msg(NULL) is dereferenced. tipc_named_node_up() runs this on &nt->cluster_scope. With a node-id configuration cluster_scope is populated only later by tipc_net_finalize(), so a peer link that comes up first reaches named_distribute() with an empty list. It is reachable by an unprivileged user (TIPC genl ops use GENL_UNS_ADMIN_PERM) over a UDP bearer in a user+net namespace: KASAN: null-ptr-deref in range [0x00000000000000d8-0x00000000000000df] RIP: 0010:tipc_named_node_up (net/tipc/name_distr.c:196) tipc_named_node_up (net/tipc/name_distr.c:196 net/tipc/name_distr.c:221) tipc_node_write_unlock (net/tipc/node.c:428) tipc_rcv (net/tipc/node.c:2185) tipc_udp_recv (net/tipc/udp_media.c:392) Kernel panic - not syncing: Fatal exception in interrupt The peer holds back this node's later name updates until it sees a bulk with the last_bulk flag, so simply skipping the empty bulk would stall it. Emit an item-less bulk when the list is empty, and break out of the build loop on allocation failure instead of returning, so the last_bulk flag is applied to the last queued skb. Fixes: cad2929dc432 ("tipc: update a binding service via broadcast") Reported-by: Xiang Mei Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Weiming Shi --- net/tipc/name_distr.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c index ba4f4906e13b..dbcfa965de34 100644 --- a/net/tipc/name_distr.c +++ b/net/tipc/name_distr.c @@ -165,7 +165,7 @@ static void named_distribute(struct net *net, struct sk_buff_head *list, dnode); if (!skb) { pr_warn("Bulk publication failure\n"); - return; + break; } hdr = buf_msg(skb); msg_set_bc_ack_invalid(hdr, true); @@ -192,6 +192,20 @@ static void named_distribute(struct net *net, struct sk_buff_head *list, skb_trim(skb, INT_H_SIZE + (msg_dsz - msg_rem)); __skb_queue_tail(list, skb); } + + if (skb_queue_empty(list)) { + skb = named_prepare_buf(net, PUBLICATION, 0, dnode); + if (!skb) { + pr_warn("Bulk publication failure\n"); + return; + } + hdr = buf_msg(skb); + msg_set_bc_ack_invalid(hdr, true); + msg_set_bulk(hdr); + msg_set_non_legacy(hdr); + __skb_queue_tail(list, skb); + } + hdr = buf_msg(skb_peek_tail(list)); msg_set_last_bulk(hdr); msg_set_named_seqno(hdr, seqno); -- 2.43.0