Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 1 | /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu> |
Patrick McHardy | f229f6c | 2013-04-06 15:24:29 +0200 | [diff] [blame] | 2 | * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 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 | */ |
| 7 | |
Pablo Neira Ayuso | ad6d950 | 2016-01-03 22:41:24 +0100 | [diff] [blame] | 8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 9 | |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 10 | #include <linux/module.h> |
| 11 | #include <linux/moduleparam.h> |
| 12 | #include <linux/in.h> |
| 13 | #include <linux/udp.h> |
Yasuyuki Kozakai | 1863f09 | 2006-12-02 22:12:54 -0800 | [diff] [blame] | 14 | #include <linux/netfilter.h> |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 15 | |
| 16 | #include <net/netfilter/nf_conntrack.h> |
| 17 | #include <net/netfilter/nf_conntrack_tuple.h> |
| 18 | #include <net/netfilter/nf_conntrack_expect.h> |
| 19 | #include <net/netfilter/nf_conntrack_ecache.h> |
| 20 | #include <net/netfilter/nf_conntrack_helper.h> |
| 21 | #include <linux/netfilter/nf_conntrack_tftp.h> |
| 22 | |
| 23 | MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>"); |
| 24 | MODULE_DESCRIPTION("TFTP connection tracking helper"); |
| 25 | MODULE_LICENSE("GPL"); |
| 26 | MODULE_ALIAS("ip_conntrack_tftp"); |
Pablo Neira Ayuso | 4dc06f9 | 2008-11-17 16:01:42 +0100 | [diff] [blame] | 27 | MODULE_ALIAS_NFCT_HELPER("tftp"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 28 | |
| 29 | #define MAX_PORTS 8 |
| 30 | static unsigned short ports[MAX_PORTS]; |
Stephen Hemminger | 2f0d2f1 | 2008-01-31 04:08:10 -0800 | [diff] [blame] | 31 | static unsigned int ports_c; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 32 | module_param_array(ports, ushort, &ports_c, 0400); |
| 33 | MODULE_PARM_DESC(ports, "Port numbers of TFTP servers"); |
| 34 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 35 | unsigned int (*nf_nat_tftp_hook)(struct sk_buff *skb, |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 36 | enum ip_conntrack_info ctinfo, |
| 37 | struct nf_conntrack_expect *exp) __read_mostly; |
| 38 | EXPORT_SYMBOL_GPL(nf_nat_tftp_hook); |
| 39 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 40 | static int tftp_help(struct sk_buff *skb, |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 41 | unsigned int protoff, |
| 42 | struct nf_conn *ct, |
| 43 | enum ip_conntrack_info ctinfo) |
| 44 | { |
Jan Engelhardt | de24b4e | 2008-01-31 04:50:51 -0800 | [diff] [blame] | 45 | const struct tftphdr *tfh; |
| 46 | struct tftphdr _tftph; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 47 | struct nf_conntrack_expect *exp; |
| 48 | struct nf_conntrack_tuple *tuple; |
| 49 | unsigned int ret = NF_ACCEPT; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 50 | typeof(nf_nat_tftp_hook) nf_nat_tftp; |
| 51 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 52 | tfh = skb_header_pointer(skb, protoff + sizeof(struct udphdr), |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 53 | sizeof(_tftph), &_tftph); |
| 54 | if (tfh == NULL) |
| 55 | return NF_ACCEPT; |
| 56 | |
| 57 | switch (ntohs(tfh->opcode)) { |
| 58 | case TFTP_OPCODE_READ: |
| 59 | case TFTP_OPCODE_WRITE: |
| 60 | /* RRQ and WRQ works the same way */ |
Jan Engelhardt | 3c9fba6 | 2008-04-14 11:15:54 +0200 | [diff] [blame] | 61 | nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); |
| 62 | nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 63 | |
Patrick McHardy | 6823645 | 2007-07-07 22:30:49 -0700 | [diff] [blame] | 64 | exp = nf_ct_expect_alloc(ct); |
Pablo Neira Ayuso | b20ab9cc | 2013-02-10 18:56:56 +0100 | [diff] [blame] | 65 | if (exp == NULL) { |
| 66 | nf_ct_helper_log(skb, ct, "cannot alloc expectation"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 67 | return NF_DROP; |
Pablo Neira Ayuso | b20ab9cc | 2013-02-10 18:56:56 +0100 | [diff] [blame] | 68 | } |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 69 | tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; |
Patrick McHardy | 5e8fbe2 | 2008-04-14 11:15:52 +0200 | [diff] [blame] | 70 | nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, |
| 71 | nf_ct_l3num(ct), |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 72 | &tuple->src.u3, &tuple->dst.u3, |
Patrick McHardy | 6823645 | 2007-07-07 22:30:49 -0700 | [diff] [blame] | 73 | IPPROTO_UDP, NULL, &tuple->dst.u.udp.port); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 74 | |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 75 | pr_debug("expect: "); |
Jan Engelhardt | 3c9fba6 | 2008-04-14 11:15:54 +0200 | [diff] [blame] | 76 | nf_ct_dump_tuple(&exp->tuple); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 77 | |
| 78 | nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook); |
| 79 | if (nf_nat_tftp && ct->status & IPS_NAT_MASK) |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 80 | ret = nf_nat_tftp(skb, ctinfo, exp); |
Pablo Neira Ayuso | b20ab9cc | 2013-02-10 18:56:56 +0100 | [diff] [blame] | 81 | else if (nf_ct_expect_related(exp) != 0) { |
| 82 | nf_ct_helper_log(skb, ct, "cannot add expectation"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 83 | ret = NF_DROP; |
Pablo Neira Ayuso | b20ab9cc | 2013-02-10 18:56:56 +0100 | [diff] [blame] | 84 | } |
Patrick McHardy | 6823645 | 2007-07-07 22:30:49 -0700 | [diff] [blame] | 85 | nf_ct_expect_put(exp); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 86 | break; |
| 87 | case TFTP_OPCODE_DATA: |
| 88 | case TFTP_OPCODE_ACK: |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 89 | pr_debug("Data/ACK opcode\n"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 90 | break; |
| 91 | case TFTP_OPCODE_ERROR: |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 92 | pr_debug("Error opcode\n"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 93 | break; |
| 94 | default: |
Patrick McHardy | 0d53778 | 2007-07-07 22:39:38 -0700 | [diff] [blame] | 95 | pr_debug("Unknown opcode\n"); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 96 | } |
| 97 | return ret; |
| 98 | } |
| 99 | |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 100 | static struct nf_conntrack_helper tftp[MAX_PORTS * 2] __read_mostly; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 101 | |
Patrick McHardy | 6002f266 | 2008-03-25 20:09:15 -0700 | [diff] [blame] | 102 | static const struct nf_conntrack_expect_policy tftp_exp_policy = { |
| 103 | .max_expected = 1, |
| 104 | .timeout = 5 * 60, |
| 105 | }; |
| 106 | |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 107 | static void nf_conntrack_tftp_fini(void) |
| 108 | { |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 109 | nf_conntrack_helpers_unregister(tftp, ports_c * 2); |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 110 | } |
| 111 | |
| 112 | static int __init nf_conntrack_tftp_init(void) |
| 113 | { |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 114 | int i, ret; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 115 | |
| 116 | if (ports_c == 0) |
| 117 | ports[ports_c++] = TFTP_PORT; |
| 118 | |
| 119 | for (i = 0; i < ports_c; i++) { |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 120 | nf_ct_helper_init(&tftp[2 * i], AF_INET, IPPROTO_UDP, "tftp", |
| 121 | TFTP_PORT, ports[i], i, &tftp_exp_policy, |
| 122 | 0, 0, tftp_help, NULL, THIS_MODULE); |
| 123 | nf_ct_helper_init(&tftp[2 * i + 1], AF_INET6, IPPROTO_UDP, "tftp", |
| 124 | TFTP_PORT, ports[i], i, &tftp_exp_policy, |
| 125 | 0, 0, tftp_help, NULL, THIS_MODULE); |
| 126 | } |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 127 | |
Gao Feng | 82de0be | 2016-07-18 11:39:23 +0800 | [diff] [blame] | 128 | ret = nf_conntrack_helpers_register(tftp, ports_c * 2); |
| 129 | if (ret < 0) { |
| 130 | pr_err("failed to register helpers\n"); |
| 131 | return ret; |
Patrick McHardy | a536df3 | 2006-12-02 22:10:18 -0800 | [diff] [blame] | 132 | } |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | module_init(nf_conntrack_tftp_init); |
| 137 | module_exit(nf_conntrack_tftp_fini); |