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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 D8EECC33C9E for ; Sat, 11 Jan 2020 10:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC1122084D for ; Sat, 11 Jan 2020 10:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578738132; bh=OgzESu4s4Pcc1zX94ABdnQJ/tjv6D4euGuRDZnjpa7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nwWxgepJJHV+lbM6UwmF/oQSXz5UuV5EuV55I7w9Kzr6jtQ6ns5GF2mggR+YQ5Ugz MPwBW27qqeE0DJhzzcNaG+vRKqHVwUtaGYFOFwMOLvYzh9jEPvz/PLG8KDZ9+u/7CA Vp5n4MRpH3VkGYZlswmEZM7GKfSoDBwjOPX12Rgc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730831AbgAKKWK (ORCPT ); Sat, 11 Jan 2020 05:22:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:41044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730662AbgAKKUI (ORCPT ); Sat, 11 Jan 2020 05:20:08 -0500 Received: from localhost (unknown [62.119.166.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 76D71205F4; Sat, 11 Jan 2020 10:20:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578738008; bh=OgzESu4s4Pcc1zX94ABdnQJ/tjv6D4euGuRDZnjpa7U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E4KHnPzatRxqYtjrs11NMDSDJ4rGEJBZ4c5GOi/1b+V+hFQm3EUbKNzejVEhCrSjh H6HDxqyxeHyVM7cikz8duavEAIa8tLai4NYhPM2eCXh3EZpgmRJqX6dWOgqEbUwsES knP7GvXZq/dJlfXWK+2LfyZ/BVVoyV7vgwpOGvnM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot+dc9071cc5a85950bdfce@syzkaller.appspotmail.com, "David S. Miller" , Florian Westphal Subject: [PATCH 4.19 72/84] pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM Date: Sat, 11 Jan 2020 10:50:49 +0100 Message-Id: <20200111094911.672249132@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200111094845.328046411@linuxfoundation.org> References: <20200111094845.328046411@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit d9e15a2733067c9328fb56d98fe8e574fa19ec31 ] As diagnosed by Florian : If TCA_FQ_QUANTUM is set to 0x80000000, fq_deueue() can loop forever in : if (f->credit <= 0) { f->credit += q->quantum; goto begin; } ... because f->credit is either 0 or -2147483648. Let's limit TCA_FQ_QUANTUM to no more than 1 << 20 : This max value should limit risks of breaking user setups while fixing this bug. Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler") Signed-off-by: Eric Dumazet Diagnosed-by: Florian Westphal Reported-by: syzbot+dc9071cc5a85950bdfce@syzkaller.appspotmail.com Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_fq.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -735,10 +735,12 @@ static int fq_change(struct Qdisc *sch, if (tb[TCA_FQ_QUANTUM]) { u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]); - if (quantum > 0) + if (quantum > 0 && quantum <= (1 << 20)) { q->quantum = quantum; - else + } else { + NL_SET_ERR_MSG_MOD(extack, "invalid quantum"); err = -EINVAL; + } } if (tb[TCA_FQ_INITIAL_QUANTUM])