From patchwork Wed Feb 7 17:42:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 870553 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3zc7wm3lNhz9ryQ for ; Thu, 8 Feb 2018 04:43:52 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754310AbeBGRmp (ORCPT ); Wed, 7 Feb 2018 12:42:45 -0500 Received: from mail.us.es ([193.147.175.20]:46980 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754141AbeBGRmk (ORCPT ); Wed, 7 Feb 2018 12:42:40 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 9AA493066AB for ; Wed, 7 Feb 2018 18:42:38 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 7D4E8DA3AE for ; Wed, 7 Feb 2018 18:42:38 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 7CAB5DA3AD; Wed, 7 Feb 2018 18:42:38 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on antivirus1-rhel7.int X-Spam-Level: X-Spam-Status: No, score=-108.2 required=7.5 tests=ALL_TRUSTED,BAYES_50, SMTPAUTH_US2,USER_IN_WHITELIST autolearn=disabled version=3.4.1 Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 0AED1DA729; Wed, 7 Feb 2018 18:42:35 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Wed, 07 Feb 2018 18:42:35 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (129.166.216.87.static.jazztel.es [87.216.166.129]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id 994A74265A2F; Wed, 7 Feb 2018 18:42:34 +0100 (CET) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 01/11] netfilter: x_tables: make allocation less aggressive Date: Wed, 7 Feb 2018 18:42:19 +0100 Message-Id: <20180207174229.4098-2-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180207174229.4098-1-pablo@netfilter.org> References: <20180207174229.4098-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Michal Hocko syzbot has noticed that xt_alloc_table_info can allocate a lot of memory. This is an admin only interface but an admin in a namespace is sufficient as well. eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_table_info()") has changed the opencoded kmalloc->vmalloc fallback into kvmalloc. It has dropped __GFP_NORETRY on the way because vmalloc has simply never fully supported __GFP_NORETRY semantic. This is still the case because e.g. page tables backing the vmalloc area are hardcoded GFP_KERNEL. Revert back to __GFP_NORETRY as a poors man defence against excessively large allocation request here. We will not rule out the OOM killer completely but __GFP_NORETRY should at least stop the large request in most cases. [akpm@linux-foundation.org: coding-style fixes] Fixes: eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_tableLink: http://lkml.kernel.org/r/20180130140104.GE21609@dhcp22.suse.cz Signed-off-by: Michal Hocko Acked-by: Florian Westphal Reviewed-by: Andrew Morton Cc: David S. Miller Signed-off-by: Andrew Morton Signed-off-by: Pablo Neira Ayuso --- net/netfilter/x_tables.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 8fa4d37141a7..2f685ee1f9c8 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1008,7 +1008,12 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size) if ((size >> PAGE_SHIFT) + 2 > totalram_pages) return NULL; - info = kvmalloc(sz, GFP_KERNEL); + /* __GFP_NORETRY is not fully supported by kvmalloc but it should + * work reasonably well if sz is too large and bail out rather + * than shoot all processes down before realizing there is nothing + * more to reclaim. + */ + info = kvmalloc(sz, GFP_KERNEL | __GFP_NORETRY); if (!info) return NULL;