From c38c4597e4bf3e99860eac98211748e1ecb0e139 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 7 Dec 2015 17:38:55 -0500 Subject: [PATCH] netfilter: implement xt_cgroup cgroup2 path match This patch implements xt_cgroup path match which matches cgroup2 membership of the associated socket. The match is recursive and invertible. For rationales on introducing another cgroup based match, please refer to a preceding commit "sock, cgroup: add sock->sk_cgroup". v3: Folded into xt_cgroup as a new revision interface as suggested by Pablo. v2: Included linux/limits.h from xt_cgroup2.h for PATH_MAX. Added explicit alignment to the priv field. Both suggested by Jan. Signed-off-by: Tejun Heo Cc: Daniel Borkmann Cc: Daniel Wagner CC: Neil Horman Cc: Jan Engelhardt Cc: Pablo Neira Ayuso Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/xt_cgroup.h | 13 +++++ net/netfilter/xt_cgroup.c | 69 ++++++++++++++++++++++++ 2 files changed, 82 insertions(+) diff --git a/include/uapi/linux/netfilter/xt_cgroup.h b/include/uapi/linux/netfilter/xt_cgroup.h index 577c9e0b9406..1e4b37b93bef 100644 --- a/include/uapi/linux/netfilter/xt_cgroup.h +++ b/include/uapi/linux/netfilter/xt_cgroup.h @@ -2,10 +2,23 @@ #define _UAPI_XT_CGROUP_H #include +#include struct xt_cgroup_info_v0 { __u32 id; __u32 invert; }; +struct xt_cgroup_info_v1 { + __u8 has_path; + __u8 has_classid; + __u8 invert_path; + __u8 invert_classid; + char path[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 17300256772a..a086a914865f 100644 --- a/net/netfilter/xt_cgroup.c +++ b/net/netfilter/xt_cgroup.c @@ -34,6 +34,37 @@ static int cgroup_mt_check_v0(const struct xt_mtchk_param *par) return 0; } +static int cgroup_mt_check_v1(const struct xt_mtchk_param *par) +{ + struct xt_cgroup_info_v1 *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("xt_cgroup: both path and classid specified\n"); + return -EINVAL; + } + + if (info->has_path) { + cgrp = cgroup_get_from_path(info->path); + if (IS_ERR(cgrp)) { + pr_info("xt_cgroup: 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) { @@ -46,6 +77,31 @@ cgroup_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) info->invert; } +static bool cgroup_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_cgroup_info_v1 *info = par->matchinfo; + struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data; + struct cgroup *ancestor = info->priv; + + if (!skb->sk || !sk_fullsock(skb->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; + + if (info->priv) + cgroup_put(info->priv); +} + static struct xt_match cgroup_mt_reg[] __read_mostly = { { .name = "cgroup", @@ -59,6 +115,19 @@ static struct xt_match cgroup_mt_reg[] __read_mostly = { (1 << NF_INET_POST_ROUTING) | (1 << NF_INET_LOCAL_IN), }, + { + .name = "cgroup", + .revision = 1, + .family = NFPROTO_UNSPEC, + .checkentry = cgroup_mt_check_v1, + .match = cgroup_mt_v1, + .matchsize = sizeof(struct xt_cgroup_info_v1), + .destroy = cgroup_mt_destroy_v1, + .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)