r4sas/ts3init_linux_netfilter_module
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This commit is contained in:
Maximilian Münchow 2016-10-13 12:46:50 +02:00
parent 5a002888d0
commit 9e1f4cb760
6 changed files with 99 additions and 0 deletions
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12
src/ts3init_cache.h
View File

@ -1,10 +1,22 @@
#ifndef _TS3INIT_CACHE_H
#define _TS3INIT_CACHE_H
/*
* Returns the current unix_time from cache, updated once every second.
*/
time_t ts3init_get_cached_unix_time(void);
/*
* Returns the cookie for a packet_index.
* If the cookie is not in the cache, it will be generated using the seed.
*/
bool ts3init_get_cookie_for_packet_index(u8 packet_index, const u8* seed, u64 (*cookie)[2]);
/*
* Returns the current cookie and packet_index.
* If the cookie is not in the cache, it will be generated using the seed.
*/
bool ts3init_get_current_cookie(const u8* seed, u64 (*cookie)[2], u8 *packet_index);
#endif /* _TS3INIT_CACHE_H */

10
src/ts3init_cookie.h
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@ -16,10 +16,20 @@ struct xt_ts3init_cookie_cache
};
};
/*
* Returns the cookie that fits current_time and packet_index.
* If the cookie is missing in cache it will be generated using
* cookie_seed and current_time
*/
__u64* ts3init_get_cookie_seed(time_t current_time, __u8 packet_index,
struct xt_ts3init_cookie_cache* cache,
const __u8* cookie_seed);
/*
* Returns the hash of cookie and source/destination address/port.
* Ip and udp are the recieved headers from the client, k0 and k1 are the
* cookie, and out is the resulting hash.
*/
int ts3init_calculate_cookie_ipv6(const struct ipv6hdr *ip, const struct udphdr *udp,
__u64 k0, __u64 k1, __u64* out);
int ts3init_calculate_cookie_ipv4(const struct iphdr *ip, const struct udphdr *udp,

7
src/ts3init_cookie_seed.h
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@ -6,6 +6,10 @@ enum {
COOKIE_PATH_MAX = 256,
};
/*
* Parses a hexstring into dest.
* It is assumed that COOKIE_SEED_LEN bytes are to be parsed.
*/
static inline bool hex2int_seed(const char *src, __u8* dst)
{
int i, j;
@ -28,6 +32,9 @@ static inline bool hex2int_seed(const char *src, __u8* dst)
#ifndef __KERNEL__
/*
* Reads a cookie seed from a file.
*/
static inline bool read_cookie_seed_from_file(const char *module_name, const char *path, __u8* dst)
{
int n, fd;

9
src/ts3init_header.h
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@ -1,6 +1,9 @@
#ifndef _TS3INIT_HEADER_H
#define _TS3INIT_HEADER_H
/*
* Magic number of a TS3INIT packet.
*/
struct ts3_init_header_tag
{
union
@ -10,6 +13,9 @@ struct ts3_init_header_tag
};
};
/*
* Header of a TS3INIT client packet.
*/
struct ts3_init_header
{
struct ts3_init_header_tag tag;
@ -21,6 +27,9 @@ struct ts3_init_header
__u8 payload[20];
};
/*
* The available TS3INIT commands, both client and server.
*/
enum
{
COMMAND_GET_COOKIE = 0,

23
src/ts3init_match.c
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@ -26,6 +26,7 @@
#include "ts3init_header.h"
#include "ts3init_cache.h"
/* Magic number of a TS3INIT packet. */
static const struct ts3_init_header_tag ts3init_header_tag_signature =
{ .tag8 = {'T', 'S', '3', 'I', 'N', 'I', 'T', '1'} };
@ -39,6 +40,10 @@ struct ts3_init_checked_header_data
static const int header_size = 18;
static int ts3init_payload_sizes[] = { 16, 20, 20, 244, -1, 1 };
/*
* Check that skb contains a valid TS3INIT client header.
* Also initializes header_data, and checks client version.
*/
static bool check_header(const struct sk_buff *skb, const struct xt_action_param *par,
struct ts3_init_checked_header_data* header_data, __u32 min_client_version)
{
@ -89,6 +94,9 @@ static bool check_header(const struct sk_buff *skb, const struct xt_action_param
return true;
}
/*
* Hashes the cookie with source/destination address/port.
*/
static int calculate_cookie(const struct sk_buff *skb, const struct xt_action_param *par,
struct udphdr *udp, __u64 k0, __u64 k1, __u64* out)
{
@ -127,6 +135,10 @@ static int calculate_cookie(const struct sk_buff *skb, const struct xt_action_pa
}
}
/*
* The 'ts3init_get_cookie' match handler.
* Checks that the packet is a valid COMMAND_GET_COOKIE.
*/
static bool
ts3init_get_cookie_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
@ -156,6 +168,9 @@ ts3init_get_cookie_mt(const struct sk_buff *skb, struct xt_action_param *par)
return true;
}
/*
* Validates matchinfo recieved from userspace.
*/
static int ts3init_get_cookie_mt_check(const struct xt_mtchk_param *par)
{
struct xt_ts3init_get_cookie_mtinfo *info = par->matchinfo;
@ -181,6 +196,11 @@ static int ts3init_get_cookie_mt_check(const struct xt_mtchk_param *par)
return 0;
}
/*
* The 'ts3init_get_cookie' match handler.
* Checks that the packet is a valid COMMAND_GET_PUZZLE, and if the replied
* with the correct cookie.
*/
static bool ts3init_get_puzzle_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_ts3init_get_puzzle_mtinfo *info = par->matchinfo;
@ -218,6 +238,9 @@ static bool ts3init_get_puzzle_mt(const struct sk_buff *skb, struct xt_action_pa
return true;
}
/*
* Validates matchinfo recieved from userspace.
*/
static int ts3init_get_puzzle_mt_check(const struct xt_mtchk_param *par)
{
struct xt_ts3init_get_puzzle_mtinfo *info = par->matchinfo;

38
src/ts3init_target.c
View File

@ -32,6 +32,9 @@
#include "ts3init_cache.h"
/*
* Send a reply back to the client
*/
static bool
ts3init_send_ipv6_reply(struct sk_buff *oldskb, const struct xt_action_param *par,
const struct ipv6hdr *oldip, const struct udphdr *oldudp,
@ -105,6 +108,9 @@ ts3init_send_ipv6_reply(struct sk_buff *oldskb, const struct xt_action_param *pa
return false;
}
/*
* Send a reply back to the client
*/
static bool
ts3init_send_ipv4_reply(struct sk_buff *oldskb, const struct xt_action_param *par,
const struct iphdr *oldip, const struct udphdr *oldudp,
@ -170,8 +176,13 @@ ts3init_send_ipv4_reply(struct sk_buff *oldskb, const struct xt_action_param *pa
return false;
}
/* The payload replied by TS3INIT_RESET. */
static const char ts3init_reset_packet[] = {'T', 'S', '3', 'I', 'N', 'I', 'T', '1', 0x65, 0, 0x88, COMMAND_RESET, 0 };
/*
* The 'TS3INIT_RESET' target handler.
* Always replies with COMMAND_RESET and drops the packet
*/
static unsigned int
ts3init_reset_ipv4_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
@ -186,6 +197,10 @@ ts3init_reset_ipv4_tg(struct sk_buff *skb, const struct xt_action_param *par)
return NF_DROP;
}
/*
* The 'TS3INIT_RESET' target handler.
* Always replies with COMMAND_RESET and drops the packet.
*/
static unsigned int
ts3init_reset_ipv6_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
@ -200,8 +215,13 @@ ts3init_reset_ipv6_tg(struct sk_buff *skb, const struct xt_action_param *par)
return NF_DROP;
}
/* The header replied by TS3INIT_SET_COOKIE. */
static const char ts3init_set_cookie_packet_header[12] = {'T', 'S', '3', 'I', 'N', 'I', 'T', '1', 0x65, 0, 0x88, COMMAND_SET_COOKIE };
/*
* Returns the current cookie hashed with source/destination address/port,
* and the current packet_index.
*/
static bool
ts3init_generate_cookie_ipv4(const struct xt_action_param *par,
const struct iphdr *ip, const struct udphdr *udp,
@ -217,6 +237,10 @@ ts3init_generate_cookie_ipv4(const struct xt_action_param *par,
return true;
}
/*
* Returns the current cookie hashed with source/destination address/port,
* and the current packet_index.
*/
static bool
ts3init_generate_cookie_ipv6(const struct xt_action_param *par,
const struct ipv6hdr *ip, const struct udphdr *udp,
@ -232,6 +256,9 @@ ts3init_generate_cookie_ipv6(const struct xt_action_param *par,
return true;
}
/*
* Fills 'newpayload' with a TS3INIT_SET_COOKIE packet.
*/
static bool
ts3init_fill_set_cookie_payload(const struct sk_buff *skb,
const struct xt_action_param *par,
@ -273,6 +300,10 @@ ts3init_fill_set_cookie_payload(const struct sk_buff *skb,
return true;
}
/*
* The 'TS3INIT_SET_COOKIE' target handler.
* Always replies with TS3INIT_SET_COOKIE and drops the packet.
*/
static unsigned int
ts3init_set_cookie_ipv4_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
@ -295,6 +326,10 @@ ts3init_set_cookie_ipv4_tg(struct sk_buff *skb, const struct xt_action_param *pa
return NF_DROP;
}
/*
* The 'TS3INIT_SET_COOKIE' target handler.
* Always replies with TS3INIT_SET_COOKIE and drops the packet.
*/
static unsigned int
ts3init_set_cookie_ipv6_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
@ -317,6 +352,9 @@ ts3init_set_cookie_ipv6_tg(struct sk_buff *skb, const struct xt_action_param *pa
return NF_DROP;
}
/*
* Validates targinfo recieved from userspace.
*/
static int ts3init_set_cookie_tg_check(const struct xt_tgchk_param *par)
{
struct xt_ts3init_set_cookie_tginfo *info = par->targinfo;