1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Xtables module to match the process control group. |
4 | * |
5 | * Might be used to implement individual "per-application" firewall |
6 | * policies in contrast to global policies based on control groups. |
7 | * Matching is based upon processes tagged to net_cls' classid marker. |
8 | * |
9 | * (C) 2013 Daniel Borkmann <dborkman@redhat.com> |
10 | */ |
11 | |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | |
14 | #include <linux/skbuff.h> |
15 | #include <linux/module.h> |
16 | #include <linux/netfilter/x_tables.h> |
17 | #include <linux/netfilter/xt_cgroup.h> |
18 | #include <net/sock.h> |
19 | |
20 | MODULE_LICENSE("GPL" ); |
21 | MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>" ); |
22 | MODULE_DESCRIPTION("Xtables: process control group matching" ); |
23 | MODULE_ALIAS("ipt_cgroup" ); |
24 | MODULE_ALIAS("ip6t_cgroup" ); |
25 | |
26 | static int cgroup_mt_check_v0(const struct xt_mtchk_param *par) |
27 | { |
28 | struct xt_cgroup_info_v0 *info = par->matchinfo; |
29 | |
30 | if (info->invert & ~1) |
31 | return -EINVAL; |
32 | |
33 | return 0; |
34 | } |
35 | |
36 | static int cgroup_mt_check_v1(const struct xt_mtchk_param *par) |
37 | { |
38 | struct xt_cgroup_info_v1 *info = par->matchinfo; |
39 | struct cgroup *cgrp; |
40 | |
41 | if ((info->invert_path & ~1) || (info->invert_classid & ~1)) |
42 | return -EINVAL; |
43 | |
44 | if (!info->has_path && !info->has_classid) { |
45 | pr_info("xt_cgroup: no path or classid specified\n" ); |
46 | return -EINVAL; |
47 | } |
48 | |
49 | if (info->has_path && info->has_classid) { |
50 | pr_info_ratelimited("path and classid specified\n" ); |
51 | return -EINVAL; |
52 | } |
53 | |
54 | info->priv = NULL; |
55 | if (info->has_path) { |
56 | cgrp = cgroup_get_from_path(path: info->path); |
57 | if (IS_ERR(ptr: cgrp)) { |
58 | pr_info_ratelimited("invalid path, errno=%ld\n" , |
59 | PTR_ERR(cgrp)); |
60 | return -EINVAL; |
61 | } |
62 | info->priv = cgrp; |
63 | } |
64 | |
65 | return 0; |
66 | } |
67 | |
68 | static int cgroup_mt_check_v2(const struct xt_mtchk_param *par) |
69 | { |
70 | struct xt_cgroup_info_v2 *info = par->matchinfo; |
71 | struct cgroup *cgrp; |
72 | |
73 | if ((info->invert_path & ~1) || (info->invert_classid & ~1)) |
74 | return -EINVAL; |
75 | |
76 | if (!info->has_path && !info->has_classid) { |
77 | pr_info("xt_cgroup: no path or classid specified\n" ); |
78 | return -EINVAL; |
79 | } |
80 | |
81 | if (info->has_path && info->has_classid) { |
82 | pr_info_ratelimited("path and classid specified\n" ); |
83 | return -EINVAL; |
84 | } |
85 | |
86 | info->priv = NULL; |
87 | if (info->has_path) { |
88 | cgrp = cgroup_get_from_path(path: info->path); |
89 | if (IS_ERR(ptr: cgrp)) { |
90 | pr_info_ratelimited("invalid path, errno=%ld\n" , |
91 | PTR_ERR(cgrp)); |
92 | return -EINVAL; |
93 | } |
94 | info->priv = cgrp; |
95 | } |
96 | |
97 | return 0; |
98 | } |
99 | |
100 | static bool |
101 | cgroup_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) |
102 | { |
103 | const struct xt_cgroup_info_v0 *info = par->matchinfo; |
104 | struct sock *sk = skb->sk; |
105 | |
106 | if (!sk || !sk_fullsock(sk) || !net_eq(net1: xt_net(par), net2: sock_net(sk))) |
107 | return false; |
108 | |
109 | return (info->id == sock_cgroup_classid(skcd: &skb->sk->sk_cgrp_data)) ^ |
110 | info->invert; |
111 | } |
112 | |
113 | static bool cgroup_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) |
114 | { |
115 | const struct xt_cgroup_info_v1 *info = par->matchinfo; |
116 | struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data; |
117 | struct cgroup *ancestor = info->priv; |
118 | struct sock *sk = skb->sk; |
119 | |
120 | if (!sk || !sk_fullsock(sk) || !net_eq(net1: xt_net(par), net2: sock_net(sk))) |
121 | return false; |
122 | |
123 | if (ancestor) |
124 | return cgroup_is_descendant(cgrp: sock_cgroup_ptr(skcd), ancestor) ^ |
125 | info->invert_path; |
126 | else |
127 | return (info->classid == sock_cgroup_classid(skcd)) ^ |
128 | info->invert_classid; |
129 | } |
130 | |
131 | static bool cgroup_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) |
132 | { |
133 | const struct xt_cgroup_info_v2 *info = par->matchinfo; |
134 | struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data; |
135 | struct cgroup *ancestor = info->priv; |
136 | struct sock *sk = skb->sk; |
137 | |
138 | if (!sk || !sk_fullsock(sk) || !net_eq(net1: xt_net(par), net2: sock_net(sk))) |
139 | return false; |
140 | |
141 | if (ancestor) |
142 | return cgroup_is_descendant(cgrp: sock_cgroup_ptr(skcd), ancestor) ^ |
143 | info->invert_path; |
144 | else |
145 | return (info->classid == sock_cgroup_classid(skcd)) ^ |
146 | info->invert_classid; |
147 | } |
148 | |
149 | static void cgroup_mt_destroy_v1(const struct xt_mtdtor_param *par) |
150 | { |
151 | struct xt_cgroup_info_v1 *info = par->matchinfo; |
152 | |
153 | if (info->priv) |
154 | cgroup_put(cgrp: info->priv); |
155 | } |
156 | |
157 | static void cgroup_mt_destroy_v2(const struct xt_mtdtor_param *par) |
158 | { |
159 | struct xt_cgroup_info_v2 *info = par->matchinfo; |
160 | |
161 | if (info->priv) |
162 | cgroup_put(cgrp: info->priv); |
163 | } |
164 | |
165 | static struct xt_match cgroup_mt_reg[] __read_mostly = { |
166 | { |
167 | .name = "cgroup" , |
168 | .revision = 0, |
169 | .family = NFPROTO_UNSPEC, |
170 | .checkentry = cgroup_mt_check_v0, |
171 | .match = cgroup_mt_v0, |
172 | .matchsize = sizeof(struct xt_cgroup_info_v0), |
173 | .me = THIS_MODULE, |
174 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
175 | (1 << NF_INET_POST_ROUTING) | |
176 | (1 << NF_INET_LOCAL_IN), |
177 | }, |
178 | { |
179 | .name = "cgroup" , |
180 | .revision = 1, |
181 | .family = NFPROTO_UNSPEC, |
182 | .checkentry = cgroup_mt_check_v1, |
183 | .match = cgroup_mt_v1, |
184 | .matchsize = sizeof(struct xt_cgroup_info_v1), |
185 | .usersize = offsetof(struct xt_cgroup_info_v1, priv), |
186 | .destroy = cgroup_mt_destroy_v1, |
187 | .me = THIS_MODULE, |
188 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
189 | (1 << NF_INET_POST_ROUTING) | |
190 | (1 << NF_INET_LOCAL_IN), |
191 | }, |
192 | { |
193 | .name = "cgroup" , |
194 | .revision = 2, |
195 | .family = NFPROTO_UNSPEC, |
196 | .checkentry = cgroup_mt_check_v2, |
197 | .match = cgroup_mt_v2, |
198 | .matchsize = sizeof(struct xt_cgroup_info_v2), |
199 | .usersize = offsetof(struct xt_cgroup_info_v2, priv), |
200 | .destroy = cgroup_mt_destroy_v2, |
201 | .me = THIS_MODULE, |
202 | .hooks = (1 << NF_INET_LOCAL_OUT) | |
203 | (1 << NF_INET_POST_ROUTING) | |
204 | (1 << NF_INET_LOCAL_IN), |
205 | }, |
206 | }; |
207 | |
208 | static int __init cgroup_mt_init(void) |
209 | { |
210 | return xt_register_matches(match: cgroup_mt_reg, ARRAY_SIZE(cgroup_mt_reg)); |
211 | } |
212 | |
213 | static void __exit cgroup_mt_exit(void) |
214 | { |
215 | xt_unregister_matches(match: cgroup_mt_reg, ARRAY_SIZE(cgroup_mt_reg)); |
216 | } |
217 | |
218 | module_init(cgroup_mt_init); |
219 | module_exit(cgroup_mt_exit); |
220 | |