From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83570C433E0 for ; Fri, 22 Jan 2021 14:24:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CC75239D1 for ; Fri, 22 Jan 2021 14:24:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728658AbhAVOYb (ORCPT ); Fri, 22 Jan 2021 09:24:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:34950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728428AbhAVOPL (ORCPT ); Fri, 22 Jan 2021 09:15:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8B4B8239EE; Fri, 22 Jan 2021 14:11:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611324709; bh=zMUBhIrBMWSQJ/8uoD2Svo4/FRyX8kp+w3+5tktxVBo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=It21UrUCzCY9lZpZ44S+Q30mUMjmi40uZjvLlpB3Nxx8iv1eJn/7JWVBJcAfkfSeh mzZjLN5Fbk1tAM+gnMqB62dIUNkjn3/1u/Zc59Og4XgyOTKqNQouIUP6jm7iFGWdKQ TkNlDiwpzOSWsKZeB7vatZBwholNmjnlSNUI8/bA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jon Maloy , Hoang Le , Jakub Kicinski Subject: [PATCH 4.9 34/35] tipc: fix NULL deref in tipc_link_xmit() Date: Fri, 22 Jan 2021 15:10:36 +0100 Message-Id: <20210122135733.695282527@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210122135732.357969201@linuxfoundation.org> References: <20210122135732.357969201@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hoang Le [ Upstream commit b77413446408fdd256599daf00d5be72b5f3e7c6 ] The buffer list can have zero skb as following path: tipc_named_node_up()->tipc_node_xmit()->tipc_link_xmit(), so we need to check the list before casting an &sk_buff. Fault report: [] tipc: Bulk publication failure [] general protection fault, probably for non-canonical [#1] PREEMPT [...] [] KASAN: null-ptr-deref in range [0x00000000000000c8-0x00000000000000cf] [] CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 5.10.0-rc4+ #2 [] Hardware name: Bochs ..., BIOS Bochs 01/01/2011 [] RIP: 0010:tipc_link_xmit+0xc1/0x2180 [] Code: 24 b8 00 00 00 00 4d 39 ec 4c 0f 44 e8 e8 d7 0a 10 f9 48 [...] [] RSP: 0018:ffffc90000006ea0 EFLAGS: 00010202 [] RAX: dffffc0000000000 RBX: ffff8880224da000 RCX: 1ffff11003d3cc0d [] RDX: 0000000000000019 RSI: ffffffff886007b9 RDI: 00000000000000c8 [] RBP: ffffc90000007018 R08: 0000000000000001 R09: fffff52000000ded [] R10: 0000000000000003 R11: fffff52000000dec R12: ffffc90000007148 [] R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000007018 [] FS: 0000000000000000(0000) GS:ffff888037400000(0000) knlGS:000[...] [] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [] CR2: 00007fffd2db5000 CR3: 000000002b08f000 CR4: 00000000000006f0 Fixes: af9b028e270fd ("tipc: make media xmit call outside node spinlock context") Acked-by: Jon Maloy Signed-off-by: Hoang Le Link: https://lore.kernel.org/r/20210108071337.3598-1-hoang.h.le@dektech.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/tipc/link.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -877,9 +877,8 @@ void tipc_link_reset(struct tipc_link *l int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list, struct sk_buff_head *xmitq) { - struct tipc_msg *hdr = buf_msg(skb_peek(list)); unsigned int maxwin = l->window; - unsigned int i, imp = msg_importance(hdr); + unsigned int i; unsigned int mtu = l->mtu; u16 ack = l->rcv_nxt - 1; u16 seqno = l->snd_nxt; @@ -888,7 +887,13 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *backlogq = &l->backlogq; struct sk_buff *skb, *_skb, *bskb; int pkt_cnt = skb_queue_len(list); + struct tipc_msg *hdr; + int imp; + if (pkt_cnt <= 0) + return 0; + + imp = msg_importance(hdr); /* Match msg importance against this and all higher backlog limits: */ if (!skb_queue_empty(backlogq)) { for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) { @@ -896,6 +901,8 @@ int tipc_link_xmit(struct tipc_link *l, return link_schedule_user(l, list); } } + + hdr = buf_msg(skb_peek(list)); if (unlikely(msg_size(hdr) > mtu)) { skb_queue_purge(list); return -EMSGSIZE;