Contributors: 15
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Harald Welte |
724 |
43.75% |
6 |
10.53% |
| Jan Engelhardt |
214 |
12.93% |
15 |
26.32% |
| Patrick McHardy |
194 |
11.72% |
9 |
15.79% |
| Linus Torvalds (pre-git) |
174 |
10.51% |
8 |
14.04% |
| Florian Westphal |
104 |
6.28% |
2 |
3.51% |
| Yasuyuki Kozakai |
52 |
3.14% |
6 |
10.53% |
| David S. Miller |
45 |
2.72% |
2 |
3.51% |
| Gerrit Renker |
45 |
2.72% |
1 |
1.75% |
| Linus Torvalds |
32 |
1.93% |
1 |
1.75% |
| Rusty Russell |
32 |
1.93% |
2 |
3.51% |
| Pablo Neira Ayuso |
17 |
1.03% |
1 |
1.75% |
| Jamal Hadi Salim |
15 |
0.91% |
1 |
1.75% |
| Joe Perches |
5 |
0.30% |
1 |
1.75% |
| Jesper Bengtsson |
1 |
0.06% |
1 |
1.75% |
| Thomas Gleixner |
1 |
0.06% |
1 |
1.75% |
| Total |
1655 |
|
57 |
|
// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/module.h>
#include <net/ip.h>
#include <linux/ipv6.h>
#include <linux/icmp.h>
#include <net/ipv6.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_tcpudp.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
MODULE_DESCRIPTION("Xtables: TCP, UDP and UDP-Lite match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("xt_tcp");
MODULE_ALIAS("xt_udp");
MODULE_ALIAS("ipt_udp");
MODULE_ALIAS("ipt_tcp");
MODULE_ALIAS("ip6t_udp");
MODULE_ALIAS("ip6t_tcp");
MODULE_ALIAS("ipt_icmp");
MODULE_ALIAS("ip6t_icmp6");
/* Returns 1 if the port is matched by the range, 0 otherwise */
static inline bool
port_match(u_int16_t min, u_int16_t max, u_int16_t port, bool invert)
{
return (port >= min && port <= max) ^ invert;
}
static bool
tcp_find_option(u_int8_t option,
const struct sk_buff *skb,
unsigned int protoff,
unsigned int optlen,
bool invert,
bool *hotdrop)
{
/* tcp.doff is only 4 bits, ie. max 15 * 4 bytes */
const u_int8_t *op;
u_int8_t _opt[60 - sizeof(struct tcphdr)];
unsigned int i;
pr_debug("finding option\n");
if (!optlen)
return invert;
/* If we don't have the whole header, drop packet. */
op = skb_header_pointer(skb, protoff + sizeof(struct tcphdr),
optlen, _opt);
if (op == NULL) {
*hotdrop = true;
return false;
}
for (i = 0; i < optlen; ) {
if (op[i] == option) return !invert;
if (op[i] < 2) i++;
else i += op[i+1]?:1;
}
return invert;
}
static bool tcp_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct tcphdr *th;
struct tcphdr _tcph;
const struct xt_tcp *tcpinfo = par->matchinfo;
if (par->fragoff != 0) {
/* To quote Alan:
Don't allow a fragment of TCP 8 bytes in. Nobody normal
causes this. Its a cracker trying to break in by doing a
flag overwrite to pass the direction checks.
*/
if (par->fragoff == 1) {
pr_debug("Dropping evil TCP offset=1 frag.\n");
par->hotdrop = true;
}
/* Must not be a fragment. */
return false;
}
th = skb_header_pointer(skb, par->thoff, sizeof(_tcph), &_tcph);
if (th == NULL) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
pr_debug("Dropping evil TCP offset=0 tinygram.\n");
par->hotdrop = true;
return false;
}
if (!port_match(tcpinfo->spts[0], tcpinfo->spts[1],
ntohs(th->source),
!!(tcpinfo->invflags & XT_TCP_INV_SRCPT)))
return false;
if (!port_match(tcpinfo->dpts[0], tcpinfo->dpts[1],
ntohs(th->dest),
!!(tcpinfo->invflags & XT_TCP_INV_DSTPT)))
return false;
if (!NF_INVF(tcpinfo, XT_TCP_INV_FLAGS,
(((unsigned char *)th)[13] & tcpinfo->flg_mask) == tcpinfo->flg_cmp))
return false;
if (tcpinfo->option) {
if (th->doff * 4 < sizeof(_tcph)) {
par->hotdrop = true;
return false;
}
if (!tcp_find_option(tcpinfo->option, skb, par->thoff,
th->doff*4 - sizeof(_tcph),
tcpinfo->invflags & XT_TCP_INV_OPTION,
&par->hotdrop))
return false;
}
return true;
}
static int tcp_mt_check(const struct xt_mtchk_param *par)
{
const struct xt_tcp *tcpinfo = par->matchinfo;
/* Must specify no unknown invflags */
return (tcpinfo->invflags & ~XT_TCP_INV_MASK) ? -EINVAL : 0;
}
static bool udp_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct udphdr *uh;
struct udphdr _udph;
const struct xt_udp *udpinfo = par->matchinfo;
/* Must not be a fragment. */
if (par->fragoff != 0)
return false;
uh = skb_header_pointer(skb, par->thoff, sizeof(_udph), &_udph);
if (uh == NULL) {
/* We've been asked to examine this packet, and we
can't. Hence, no choice but to drop. */
pr_debug("Dropping evil UDP tinygram.\n");
par->hotdrop = true;
return false;
}
return port_match(udpinfo->spts[0], udpinfo->spts[1],
ntohs(uh->source),
!!(udpinfo->invflags & XT_UDP_INV_SRCPT))
&& port_match(udpinfo->dpts[0], udpinfo->dpts[1],
ntohs(uh->dest),
!!(udpinfo->invflags & XT_UDP_INV_DSTPT));
}
static int udp_mt_check(const struct xt_mtchk_param *par)
{
const struct xt_udp *udpinfo = par->matchinfo;
/* Must specify no unknown invflags */
return (udpinfo->invflags & ~XT_UDP_INV_MASK) ? -EINVAL : 0;
}
/* Returns 1 if the type and code is matched by the range, 0 otherwise */
static bool type_code_in_range(u8 test_type, u8 min_code, u8 max_code,
u8 type, u8 code)
{
return type == test_type && code >= min_code && code <= max_code;
}
static bool icmp_type_code_match(u8 test_type, u8 min_code, u8 max_code,
u8 type, u8 code, bool invert)
{
return (test_type == 0xFF ||
type_code_in_range(test_type, min_code, max_code, type, code))
^ invert;
}
static bool icmp6_type_code_match(u8 test_type, u8 min_code, u8 max_code,
u8 type, u8 code, bool invert)
{
return type_code_in_range(test_type, min_code, max_code, type, code) ^ invert;
}
static bool
icmp_match(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct icmphdr *ic;
struct icmphdr _icmph;
const struct ipt_icmp *icmpinfo = par->matchinfo;
/* Must not be a fragment. */
if (par->fragoff != 0)
return false;
ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
if (!ic) {
/* We've been asked to examine this packet, and we
* can't. Hence, no choice but to drop.
*/
par->hotdrop = true;
return false;
}
return icmp_type_code_match(icmpinfo->type,
icmpinfo->code[0],
icmpinfo->code[1],
ic->type, ic->code,
!!(icmpinfo->invflags & IPT_ICMP_INV));
}
static bool
icmp6_match(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct icmp6hdr *ic;
struct icmp6hdr _icmph;
const struct ip6t_icmp *icmpinfo = par->matchinfo;
/* Must not be a fragment. */
if (par->fragoff != 0)
return false;
ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
if (!ic) {
/* We've been asked to examine this packet, and we
* can't. Hence, no choice but to drop.
*/
par->hotdrop = true;
return false;
}
return icmp6_type_code_match(icmpinfo->type,
icmpinfo->code[0],
icmpinfo->code[1],
ic->icmp6_type, ic->icmp6_code,
!!(icmpinfo->invflags & IP6T_ICMP_INV));
}
static int icmp_checkentry(const struct xt_mtchk_param *par)
{
const struct ipt_icmp *icmpinfo = par->matchinfo;
return (icmpinfo->invflags & ~IPT_ICMP_INV) ? -EINVAL : 0;
}
static int icmp6_checkentry(const struct xt_mtchk_param *par)
{
const struct ip6t_icmp *icmpinfo = par->matchinfo;
return (icmpinfo->invflags & ~IP6T_ICMP_INV) ? -EINVAL : 0;
}
static struct xt_match tcpudp_mt_reg[] __read_mostly = {
{
.name = "tcp",
.family = NFPROTO_IPV4,
.checkentry = tcp_mt_check,
.match = tcp_mt,
.matchsize = sizeof(struct xt_tcp),
.proto = IPPROTO_TCP,
.me = THIS_MODULE,
},
{
.name = "tcp",
.family = NFPROTO_IPV6,
.checkentry = tcp_mt_check,
.match = tcp_mt,
.matchsize = sizeof(struct xt_tcp),
.proto = IPPROTO_TCP,
.me = THIS_MODULE,
},
{
.name = "udp",
.family = NFPROTO_IPV4,
.checkentry = udp_mt_check,
.match = udp_mt,
.matchsize = sizeof(struct xt_udp),
.proto = IPPROTO_UDP,
.me = THIS_MODULE,
},
{
.name = "udp",
.family = NFPROTO_IPV6,
.checkentry = udp_mt_check,
.match = udp_mt,
.matchsize = sizeof(struct xt_udp),
.proto = IPPROTO_UDP,
.me = THIS_MODULE,
},
{
.name = "udplite",
.family = NFPROTO_IPV4,
.checkentry = udp_mt_check,
.match = udp_mt,
.matchsize = sizeof(struct xt_udp),
.proto = IPPROTO_UDPLITE,
.me = THIS_MODULE,
},
{
.name = "udplite",
.family = NFPROTO_IPV6,
.checkentry = udp_mt_check,
.match = udp_mt,
.matchsize = sizeof(struct xt_udp),
.proto = IPPROTO_UDPLITE,
.me = THIS_MODULE,
},
{
.name = "icmp",
.match = icmp_match,
.matchsize = sizeof(struct ipt_icmp),
.checkentry = icmp_checkentry,
.proto = IPPROTO_ICMP,
.family = NFPROTO_IPV4,
.me = THIS_MODULE,
},
{
.name = "icmp6",
.match = icmp6_match,
.matchsize = sizeof(struct ip6t_icmp),
.checkentry = icmp6_checkentry,
.proto = IPPROTO_ICMPV6,
.family = NFPROTO_IPV6,
.me = THIS_MODULE,
},
};
static int __init tcpudp_mt_init(void)
{
return xt_register_matches(tcpudp_mt_reg, ARRAY_SIZE(tcpudp_mt_reg));
}
static void __exit tcpudp_mt_exit(void)
{
xt_unregister_matches(tcpudp_mt_reg, ARRAY_SIZE(tcpudp_mt_reg));
}
module_init(tcpudp_mt_init);
module_exit(tcpudp_mt_exit);