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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2008-2009 Patrick McHardy <[email protected]>
4 * Copyright (c) 2012-2014 Pablo Neira Ayuso <[email protected]>
5 *
6 * Development of this code funded by Astaro AG (http://www.astaro.com/)
7 */
8
9#include <linux/audit.h>
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/netlink.h>
14#include <linux/netfilter.h>
15#include <linux/netfilter/nf_tables.h>
16#include <net/ipv6.h>
17#include <net/ip.h>
18#include <net/netfilter/nf_tables.h>
19#include <net/netfilter/nf_log.h>
20#include <linux/netdevice.h>
21
22static const char *nft_log_null_prefix = "";
23
24struct nft_log {
25 struct nf_loginfo loginfo;
26 char *prefix;
27};
28
29static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
30{
31 struct sk_buff *skb = pkt->skb;
32 struct audit_buffer *ab;
33
34 if (!audit_enabled)
35 return;
36
37 ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
38 if (!ab)
39 return;
40
41 audit_log_format(ab, "mark=%#x", skb->mark);
42
43 audit_log_nf_skb(ab, skb, nft_pf(pkt));
44
45 audit_log_end(ab);
46}
47
48static void nft_log_eval(const struct nft_expr *expr,
49 struct nft_regs *regs,
50 const struct nft_pktinfo *pkt)
51{
52 const struct nft_log *priv = nft_expr_priv(expr);
53
54 if (priv->loginfo.type == NF_LOG_TYPE_LOG &&
55 priv->loginfo.u.log.level == NFT_LOGLEVEL_AUDIT) {
56 nft_log_eval_audit(pkt);
57 return;
58 }
59
60 nf_log_packet(nft_net(pkt), nft_pf(pkt), nft_hook(pkt), pkt->skb,
61 nft_in(pkt), nft_out(pkt), &priv->loginfo, "%s",
62 priv->prefix);
63}
64
65static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
66 [NFTA_LOG_GROUP] = { .type = NLA_U16 },
67 [NFTA_LOG_PREFIX] = { .type = NLA_STRING,
68 .len = NF_LOG_PREFIXLEN - 1 },
69 [NFTA_LOG_SNAPLEN] = { .type = NLA_U32 },
70 [NFTA_LOG_QTHRESHOLD] = { .type = NLA_U16 },
71 [NFTA_LOG_LEVEL] = { .type = NLA_U32 },
72 [NFTA_LOG_FLAGS] = NLA_POLICY_MASK(NLA_BE32, NF_LOG_MASK),
73};
74
75static int nft_log_modprobe(struct net *net, enum nf_log_type t)
76{
77 switch (t) {
78 case NF_LOG_TYPE_LOG:
79 return nft_request_module(net, "%s", "nf_log_syslog");
80 case NF_LOG_TYPE_ULOG:
81 return nft_request_module(net, "%s", "nfnetlink_log");
82 case NF_LOG_TYPE_MAX:
83 break;
84 }
85
86 return -ENOENT;
87}
88
89static int nft_log_init(const struct nft_ctx *ctx,
90 const struct nft_expr *expr,
91 const struct nlattr * const tb[])
92{
93 struct nft_log *priv = nft_expr_priv(expr);
94 struct nf_loginfo *li = &priv->loginfo;
95 const struct nlattr *nla;
96 int err;
97
98 li->type = NF_LOG_TYPE_LOG;
99 if (tb[NFTA_LOG_LEVEL] != NULL &&
100 tb[NFTA_LOG_GROUP] != NULL)
101 return -EINVAL;
102 if (tb[NFTA_LOG_GROUP] != NULL) {
103 li->type = NF_LOG_TYPE_ULOG;
104 if (tb[NFTA_LOG_FLAGS] != NULL)
105 return -EINVAL;
106 }
107
108 nla = tb[NFTA_LOG_PREFIX];
109 if (nla != NULL) {
110 priv->prefix = kmalloc(nla_len(nla) + 1, GFP_KERNEL_ACCOUNT);
111 if (priv->prefix == NULL)
112 return -ENOMEM;
113 nla_strscpy(priv->prefix, nla, nla_len(nla) + 1);
114 } else {
115 priv->prefix = (char *)nft_log_null_prefix;
116 }
117
118 switch (li->type) {
119 case NF_LOG_TYPE_LOG:
120 if (tb[NFTA_LOG_LEVEL] != NULL) {
121 li->u.log.level =
122 ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
123 } else {
124 li->u.log.level = NFT_LOGLEVEL_WARNING;
125 }
126 if (li->u.log.level > NFT_LOGLEVEL_AUDIT) {
127 err = -EINVAL;
128 goto err1;
129 }
130
131 if (tb[NFTA_LOG_FLAGS] != NULL) {
132 li->u.log.logflags =
133 ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
134 if (li->u.log.logflags & ~NF_LOG_MASK) {
135 err = -EINVAL;
136 goto err1;
137 }
138 }
139 break;
140 case NF_LOG_TYPE_ULOG:
141 li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
142 if (tb[NFTA_LOG_SNAPLEN] != NULL) {
143 li->u.ulog.flags |= NF_LOG_F_COPY_LEN;
144 li->u.ulog.copy_len =
145 ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
146 }
147 if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
148 li->u.ulog.qthreshold =
149 ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
150 }
151 break;
152 }
153
154 if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
155 return 0;
156
157 err = nf_logger_find_get(ctx->family, li->type);
158 if (err < 0) {
159 if (nft_log_modprobe(ctx->net, li->type) == -EAGAIN)
160 err = -EAGAIN;
161
162 goto err1;
163 }
164
165 return 0;
166
167err1:
168 if (priv->prefix != nft_log_null_prefix)
169 kfree(priv->prefix);
170 return err;
171}
172
173static void nft_log_destroy(const struct nft_ctx *ctx,
174 const struct nft_expr *expr)
175{
176 struct nft_log *priv = nft_expr_priv(expr);
177 struct nf_loginfo *li = &priv->loginfo;
178
179 if (priv->prefix != nft_log_null_prefix)
180 kfree(priv->prefix);
181
182 if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
183 return;
184
185 nf_logger_put(ctx->family, li->type);
186}
187
188static int nft_log_dump(struct sk_buff *skb,
189 const struct nft_expr *expr, bool reset)
190{
191 const struct nft_log *priv = nft_expr_priv(expr);
192 const struct nf_loginfo *li = &priv->loginfo;
193
194 if (priv->prefix != nft_log_null_prefix)
195 if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
196 goto nla_put_failure;
197 switch (li->type) {
198 case NF_LOG_TYPE_LOG:
199 if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
200 goto nla_put_failure;
201
202 if (li->u.log.logflags) {
203 if (nla_put_be32(skb, NFTA_LOG_FLAGS,
204 htonl(li->u.log.logflags)))
205 goto nla_put_failure;
206 }
207 break;
208 case NF_LOG_TYPE_ULOG:
209 if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
210 goto nla_put_failure;
211
212 if (li->u.ulog.flags & NF_LOG_F_COPY_LEN) {
213 if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
214 htonl(li->u.ulog.copy_len)))
215 goto nla_put_failure;
216 }
217 if (li->u.ulog.qthreshold) {
218 if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
219 htons(li->u.ulog.qthreshold)))
220 goto nla_put_failure;
221 }
222 break;
223 }
224 return 0;
225
226nla_put_failure:
227 return -1;
228}
229
230static struct nft_expr_type nft_log_type;
231static const struct nft_expr_ops nft_log_ops = {
232 .type = &nft_log_type,
233 .size = NFT_EXPR_SIZE(sizeof(struct nft_log)),
234 .eval = nft_log_eval,
235 .init = nft_log_init,
236 .destroy = nft_log_destroy,
237 .dump = nft_log_dump,
238};
239
240static struct nft_expr_type nft_log_type __read_mostly = {
241 .name = "log",
242 .ops = &nft_log_ops,
243 .policy = nft_log_policy,
244 .maxattr = NFTA_LOG_MAX,
245 .owner = THIS_MODULE,
246};
247
248static int __init nft_log_module_init(void)
249{
250 return nft_register_expr(&nft_log_type);
251}
252
253static void __exit nft_log_module_exit(void)
254{
255 nft_unregister_expr(&nft_log_type);
256}
257
258module_init(nft_log_module_init);
259module_exit(nft_log_module_exit);
260
261MODULE_LICENSE("GPL");
262MODULE_AUTHOR("Patrick McHardy <[email protected]>");
263MODULE_ALIAS_NFT_EXPR("log");
264MODULE_DESCRIPTION("Netfilter nf_tables log module");