From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 08/31] netfilter: xt_cgroup: shrink size of v2 path Date: Tue, 9 Oct 2018 01:01:02 +0200 Message-ID: <20181008230125.2330-9-pablo@netfilter.org> References: <20181008230125.2330-1-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:56250 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726461AbeJIGPn (ORCPT ); Tue, 9 Oct 2018 02:15:43 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id CAC2753AA3E for ; Tue, 9 Oct 2018 01:01:38 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id B7445DA85E for ; Tue, 9 Oct 2018 01:01:38 +0200 (CEST) In-Reply-To: <20181008230125.2330-1-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-ID: cgroup v2 path field is PATH_MAX which is too large, this is placing too much pressure on memory allocation for people with many rules doing cgroup v1 classid matching, side effects of this are bug reports like: https://bugzilla.kernel.org/show_bug.cgi?id=200639 This patch registers a new revision that shrinks the cgroup path to 512 bytes, which is the same approach we follow in similar extensions that have a path field. Cc: Tejun Heo Signed-off-by: Pablo Neira Ayuso Acked-by: Tejun Heo --- include/uapi/linux/netfilter/xt_cgroup.h | 16 +++++++ net/netfilter/xt_cgroup.c | 72 ++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/include/uapi/linux/netfilter/xt_cgroup.h b/include/uapi/linux/netfilter/xt_cgroup.h index e96dfa1b34f7..b74e370d6133 100644 --- a/include/uapi/linux/netfilter/xt_cgroup.h +++ b/include/uapi/linux/netfilter/xt_cgroup.h @@ -22,4 +22,20 @@ struct xt_cgroup_info_v1 { void *priv __attribute__((aligned(8))); }; +#define XT_CGROUP_PATH_MAX 512 + +struct xt_cgroup_info_v2 { + __u8 has_path; + __u8 has_classid; + __u8 invert_path; + __u8 invert_classid; + union { + char path[XT_CGROUP_PATH_MAX]; + __u32 classid; + }; + + /* kernel internal data */ + void *priv __attribute__((aligned(8))); +}; + #endif /* _UAPI_XT_CGROUP_H */ diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c index 5d92e1781980..5cb1ecb29ea4 100644 --- a/net/netfilter/xt_cgroup.c +++ b/net/netfilter/xt_cgroup.c @@ -68,6 +68,38 @@ static int cgroup_mt_check_v1(const struct xt_mtchk_param *par) return 0; } +static int cgroup_mt_check_v2(const struct xt_mtchk_param *par) +{ + struct xt_cgroup_info_v2 *info = par->matchinfo; + struct cgroup *cgrp; + + if ((info->invert_path & ~1) || (info->invert_classid & ~1)) + return -EINVAL; + + if (!info->has_path && !info->has_classid) { + pr_info("xt_cgroup: no path or classid specified\n"); + return -EINVAL; + } + + if (info->has_path && info->has_classid) { + pr_info_ratelimited("path and classid specified\n"); + return -EINVAL; + } + + info->priv = NULL; + if (info->has_path) { + cgrp = cgroup_get_from_path(info->path); + if (IS_ERR(cgrp)) { + pr_info_ratelimited("invalid path, errno=%ld\n", + PTR_ERR(cgrp)); + return -EINVAL; + } + info->priv = cgrp; + } + + return 0; +} + static bool cgroup_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) { @@ -99,6 +131,24 @@ static bool cgroup_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) info->invert_classid; } +static bool cgroup_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_cgroup_info_v2 *info = par->matchinfo; + struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data; + struct cgroup *ancestor = info->priv; + struct sock *sk = skb->sk; + + if (!sk || !sk_fullsock(sk) || !net_eq(xt_net(par), sock_net(sk))) + return false; + + if (ancestor) + return cgroup_is_descendant(sock_cgroup_ptr(skcd), ancestor) ^ + info->invert_path; + else + return (info->classid == sock_cgroup_classid(skcd)) ^ + info->invert_classid; +} + static void cgroup_mt_destroy_v1(const struct xt_mtdtor_param *par) { struct xt_cgroup_info_v1 *info = par->matchinfo; @@ -107,6 +157,14 @@ static void cgroup_mt_destroy_v1(const struct xt_mtdtor_param *par) cgroup_put(info->priv); } +static void cgroup_mt_destroy_v2(const struct xt_mtdtor_param *par) +{ + struct xt_cgroup_info_v2 *info = par->matchinfo; + + if (info->priv) + cgroup_put(info->priv); +} + static struct xt_match cgroup_mt_reg[] __read_mostly = { { .name = "cgroup", @@ -134,6 +192,20 @@ static struct xt_match cgroup_mt_reg[] __read_mostly = { (1 << NF_INET_POST_ROUTING) | (1 << NF_INET_LOCAL_IN), }, + { + .name = "cgroup", + .revision = 2, + .family = NFPROTO_UNSPEC, + .checkentry = cgroup_mt_check_v2, + .match = cgroup_mt_v2, + .matchsize = sizeof(struct xt_cgroup_info_v2), + .usersize = offsetof(struct xt_cgroup_info_v2, priv), + .destroy = cgroup_mt_destroy_v2, + .me = THIS_MODULE, + .hooks = (1 << NF_INET_LOCAL_OUT) | + (1 << NF_INET_POST_ROUTING) | + (1 << NF_INET_LOCAL_IN), + }, }; static int __init cgroup_mt_init(void) -- 2.11.0