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=ham 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 52F9CC43332 for ; Fri, 22 Jan 2021 18:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39BAC23ABA for ; Fri, 22 Jan 2021 18:24:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730044AbhAVSYT (ORCPT ); Fri, 22 Jan 2021 13:24:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:38816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728584AbhAVOXQ (ORCPT ); Fri, 22 Jan 2021 09:23:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id AA36323B00; Fri, 22 Jan 2021 14:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611325049; bh=1sPWefoRRq2dMC3jN2dTikkosy66j/s6vBBM+qYnQlY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cF547jTunS+gOggp0Y+1GTKr1VrHZKRfQHiqq0Totk9m0FNdnhggktVLgt4ddqkzL GMtKVxzFM8D3BNYqzASI+sUyhRihM/ulMRIQJFc4GywV2IN7rmrQ9pB3k4Y1pwdCNw QqiaGgOuQ/1JmR4lMoX5ul68X4q1UWt5+sn4NBQQ= 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 5.4 30/33] tipc: fix NULL deref in tipc_link_xmit() Date: Fri, 22 Jan 2021 15:12:46 +0100 Message-Id: <20210122135734.787814821@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210122135733.565501039@linuxfoundation.org> References: <20210122135733.565501039@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 | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -939,9 +939,7 @@ 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; - int imp = msg_importance(hdr); unsigned int mtu = l->mtu; u16 ack = l->rcv_nxt - 1; u16 seqno = l->snd_nxt; @@ -950,8 +948,14 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *backlogq = &l->backlogq; struct sk_buff *skb, *_skb, **tskb; int pkt_cnt = skb_queue_len(list); + struct tipc_msg *hdr; int rc = 0; + int imp; + if (pkt_cnt <= 0) + return 0; + + hdr = buf_msg(skb_peek(list)); if (unlikely(msg_size(hdr) > mtu)) { pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n", skb_queue_len(list), msg_user(hdr), @@ -960,6 +964,7 @@ int tipc_link_xmit(struct tipc_link *l, return -EMSGSIZE; } + imp = msg_importance(hdr); /* Allow oversubscription of one data msg per source at congestion */ if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) { if (imp == TIPC_SYSTEM_IMPORTANCE) {