userns: don't leak root user
[wrt350n-kernel.git] / net / netfilter / nf_conntrack_tftp.c
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1 /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 as
5 * published by the Free Software Foundation.
6 */
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/in.h>
11 #include <linux/udp.h>
12 #include <linux/netfilter.h>
14 #include <net/netfilter/nf_conntrack.h>
15 #include <net/netfilter/nf_conntrack_tuple.h>
16 #include <net/netfilter/nf_conntrack_expect.h>
17 #include <net/netfilter/nf_conntrack_ecache.h>
18 #include <net/netfilter/nf_conntrack_helper.h>
19 #include <linux/netfilter/nf_conntrack_tftp.h>
21 MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
22 MODULE_DESCRIPTION("TFTP connection tracking helper");
23 MODULE_LICENSE("GPL");
24 MODULE_ALIAS("ip_conntrack_tftp");
26 #define MAX_PORTS 8
27 static unsigned short ports[MAX_PORTS];
28 static int ports_c;
29 module_param_array(ports, ushort, &ports_c, 0400);
30 MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");
32 unsigned int (*nf_nat_tftp_hook)(struct sk_buff **pskb,
33 enum ip_conntrack_info ctinfo,
34 struct nf_conntrack_expect *exp) __read_mostly;
35 EXPORT_SYMBOL_GPL(nf_nat_tftp_hook);
37 static int tftp_help(struct sk_buff **pskb,
38 unsigned int protoff,
39 struct nf_conn *ct,
40 enum ip_conntrack_info ctinfo)
42 struct tftphdr _tftph, *tfh;
43 struct nf_conntrack_expect *exp;
44 struct nf_conntrack_tuple *tuple;
45 unsigned int ret = NF_ACCEPT;
46 int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
47 typeof(nf_nat_tftp_hook) nf_nat_tftp;
49 tfh = skb_header_pointer(*pskb, protoff + sizeof(struct udphdr),
50 sizeof(_tftph), &_tftph);
51 if (tfh == NULL)
52 return NF_ACCEPT;
54 switch (ntohs(tfh->opcode)) {
55 case TFTP_OPCODE_READ:
56 case TFTP_OPCODE_WRITE:
57 /* RRQ and WRQ works the same way */
58 NF_CT_DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
59 NF_CT_DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
61 exp = nf_ct_expect_alloc(ct);
62 if (exp == NULL)
63 return NF_DROP;
64 tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
65 nf_ct_expect_init(exp, family, &tuple->src.u3, &tuple->dst.u3,
66 IPPROTO_UDP, NULL, &tuple->dst.u.udp.port);
68 pr_debug("expect: ");
69 NF_CT_DUMP_TUPLE(&exp->tuple);
71 nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook);
72 if (nf_nat_tftp && ct->status & IPS_NAT_MASK)
73 ret = nf_nat_tftp(pskb, ctinfo, exp);
74 else if (nf_ct_expect_related(exp) != 0)
75 ret = NF_DROP;
76 nf_ct_expect_put(exp);
77 break;
78 case TFTP_OPCODE_DATA:
79 case TFTP_OPCODE_ACK:
80 pr_debug("Data/ACK opcode\n");
81 break;
82 case TFTP_OPCODE_ERROR:
83 pr_debug("Error opcode\n");
84 break;
85 default:
86 pr_debug("Unknown opcode\n");
88 return ret;
91 static struct nf_conntrack_helper tftp[MAX_PORTS][2] __read_mostly;
92 static char tftp_names[MAX_PORTS][2][sizeof("tftp-65535")] __read_mostly;
94 static void nf_conntrack_tftp_fini(void)
96 int i, j;
98 for (i = 0; i < ports_c; i++) {
99 for (j = 0; j < 2; j++)
100 nf_conntrack_helper_unregister(&tftp[i][j]);
104 static int __init nf_conntrack_tftp_init(void)
106 int i, j, ret;
107 char *tmpname;
109 if (ports_c == 0)
110 ports[ports_c++] = TFTP_PORT;
112 for (i = 0; i < ports_c; i++) {
113 memset(&tftp[i], 0, sizeof(tftp[i]));
115 tftp[i][0].tuple.src.l3num = AF_INET;
116 tftp[i][1].tuple.src.l3num = AF_INET6;
117 for (j = 0; j < 2; j++) {
118 tftp[i][j].tuple.dst.protonum = IPPROTO_UDP;
119 tftp[i][j].tuple.src.u.udp.port = htons(ports[i]);
120 tftp[i][j].max_expected = 1;
121 tftp[i][j].timeout = 5 * 60; /* 5 minutes */
122 tftp[i][j].me = THIS_MODULE;
123 tftp[i][j].help = tftp_help;
125 tmpname = &tftp_names[i][j][0];
126 if (ports[i] == TFTP_PORT)
127 sprintf(tmpname, "tftp");
128 else
129 sprintf(tmpname, "tftp-%u", i);
130 tftp[i][j].name = tmpname;
132 ret = nf_conntrack_helper_register(&tftp[i][j]);
133 if (ret) {
134 printk("nf_ct_tftp: failed to register helper "
135 "for pf: %u port: %u\n",
136 tftp[i][j].tuple.src.l3num, ports[i]);
137 nf_conntrack_tftp_fini();
138 return ret;
142 return 0;
145 module_init(nf_conntrack_tftp_init);
146 module_exit(nf_conntrack_tftp_fini);