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1 | /* $Id: ip_cloaking.c 3526 2007-07-06 07:56:14Z nenolod $ */ | |
2 | ||
3 | #include "stdinc.h" | |
4 | #include "modules.h" | |
5 | #include "hook.h" | |
6 | #include "client.h" | |
7 | #include "ircd.h" | |
8 | #include "send.h" | |
9 | #include "s_conf.h" | |
10 | #include "s_user.h" | |
11 | #include "s_serv.h" | |
12 | #include "tools.h" | |
13 | #include "numeric.h" | |
14 | ||
15 | /* if you're modifying this module, you'll probably to change this */ | |
16 | #define KEY 0x13748cfa | |
17 | ||
18 | static int | |
19 | _modinit(void) | |
20 | { | |
21 | /* add the usermode to the available slot */ | |
22 | user_modes['h'] = find_umode_slot(); | |
23 | construct_umodebuf(); | |
24 | ||
25 | return 0; | |
26 | } | |
27 | ||
28 | static void | |
29 | _moddeinit(void) | |
30 | { | |
31 | /* disable the umode and remove it from the available list */ | |
32 | user_modes['h'] = 0; | |
33 | construct_umodebuf(); | |
34 | } | |
35 | ||
36 | static void check_umode_change(void *data); | |
37 | static void check_new_user(void *data); | |
38 | mapi_hfn_list_av1 ip_cloaking_hfnlist[] = { | |
39 | { "umode_changed", (hookfn) check_umode_change }, | |
40 | { "new_local_user", (hookfn) check_new_user }, | |
41 | { NULL, NULL } | |
42 | }; | |
43 | ||
44 | DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL, | |
45 | ip_cloaking_hfnlist, "$Revision: 3526 $"); | |
46 | ||
47 | static void | |
48 | distribute_hostchange(struct Client *client) | |
49 | { | |
50 | if (irccmp(client->host, client->orighost)) | |
51 | sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host", | |
52 | client->host); | |
53 | else | |
54 | sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset", | |
55 | client->host); | |
56 | ||
57 | sendto_server(NULL, NULL, | |
58 | CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s", | |
59 | use_id(&me), use_id(client), client->host); | |
60 | sendto_server(NULL, NULL, | |
61 | CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s", | |
62 | use_id(&me), use_id(client), client->host); | |
63 | sendto_server(NULL, NULL, | |
64 | NOCAPS, CAP_TS6, ":%s ENCAP * CHGHOST %s :%s", | |
65 | me.name, client->name, client->host); | |
66 | if (irccmp(client->host, client->orighost)) | |
67 | SetDynSpoof(client); | |
68 | else | |
69 | ClearDynSpoof(client); | |
70 | } | |
71 | ||
72 | #define Nval 0x8c3a48ac | |
73 | #define HOSTLEN 63 | |
74 | #define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */ | |
75 | ||
76 | static inline unsigned int | |
77 | get_string_entropy(const char *inbuf) | |
78 | { | |
79 | unsigned int accum = 1; | |
80 | ||
81 | while(*inbuf != '\0') | |
82 | accum += *inbuf++; | |
83 | ||
84 | return accum; | |
85 | } | |
86 | ||
87 | /* calls get_string_entropy() and toasts it against INITDATA */ | |
88 | static inline unsigned int | |
89 | get_string_weighted_entropy(const char *inbuf) | |
90 | { | |
91 | static int base_entropy = 0; | |
92 | unsigned int accum = get_string_entropy(inbuf); | |
93 | ||
94 | /* initialize the algorithm if it is not yet ready */ | |
95 | if (base_entropy == 0) | |
96 | base_entropy = get_string_entropy(INITDATA); | |
97 | ||
98 | return (Nval * accum) ^ base_entropy; | |
99 | } | |
100 | ||
101 | static void | |
102 | do_host_cloak_ip(const char *inbuf, char *outbuf) | |
103 | { | |
104 | char *tptr; | |
105 | unsigned int accum = get_string_weighted_entropy(inbuf); | |
106 | char buf[HOSTLEN]; | |
107 | ||
108 | strncpy(buf, inbuf, HOSTLEN); | |
109 | tptr = strrchr(buf, '.'); | |
110 | ||
111 | if (tptr == NULL) | |
112 | { | |
113 | strncpy(outbuf, inbuf, HOSTLEN); | |
114 | return; | |
115 | } | |
116 | ||
117 | *tptr++ = '\0'; | |
118 | ||
119 | snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum); | |
120 | } | |
121 | ||
122 | static void | |
123 | do_host_cloak_host(const char *inbuf, char *outbuf) | |
124 | { | |
125 | char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz"; | |
126 | char *tptr; | |
127 | unsigned int accum = get_string_weighted_entropy(inbuf); | |
128 | ||
129 | strncpy(outbuf, inbuf, HOSTLEN); | |
130 | ||
131 | /* pass 1: scramble first section of hostname using base26 | |
132 | * alphabet toasted against the weighted entropy of the string. | |
133 | * | |
134 | * numbers are not changed at this time, only letters. | |
135 | */ | |
136 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
137 | { | |
138 | if (*tptr == '.') | |
139 | break; | |
140 | ||
141 | if (isdigit(*tptr) || *tptr == '-') | |
142 | continue; | |
143 | ||
144 | *tptr = b26_alphabet[(*tptr * accum) % 26]; | |
145 | } | |
146 | ||
147 | /* pass 2: scramble each number in the address */ | |
148 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
149 | { | |
150 | if (isdigit(*tptr)) | |
151 | { | |
152 | *tptr = 48 + ((*tptr * accum) % 10); | |
153 | } | |
154 | } | |
155 | } | |
156 | ||
157 | static void | |
158 | check_umode_change(void *vdata) | |
159 | { | |
160 | hook_data_umode_changed *data = (hook_data_umode_changed *)vdata; | |
161 | struct Client *source_p = data->client; | |
162 | ||
163 | if (!MyClient(source_p)) | |
164 | return; | |
165 | ||
166 | /* didn't change +h umode, we don't need to do anything */ | |
167 | if (!((data->oldumodes ^ source_p->umodes) & user_modes['h'])) | |
168 | return; | |
169 | ||
170 | if (source_p->umodes & user_modes['h']) | |
171 | { | |
172 | if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost))) | |
173 | { | |
174 | source_p->umodes &= ~user_modes['h']; | |
175 | return; | |
176 | } | |
177 | if (strcmp(source_p->host, source_p->localClient->mangledhost)) | |
178 | { | |
179 | strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN); | |
180 | distribute_hostchange(source_p); | |
181 | } | |
182 | else /* not really nice, but we need to send this numeric here */ | |
183 | sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host", | |
184 | source_p->host); | |
185 | } | |
186 | else if (!(source_p->umodes & user_modes['h'])) | |
187 | { | |
188 | if (source_p->localClient->mangledhost != NULL && | |
189 | !strcmp(source_p->host, source_p->localClient->mangledhost)) | |
190 | { | |
191 | strlcpy(source_p->host, source_p->orighost, HOSTLEN); | |
192 | distribute_hostchange(source_p); | |
193 | } | |
194 | } | |
195 | } | |
196 | ||
197 | static void | |
198 | check_new_user(void *vdata) | |
199 | { | |
200 | struct Client *source_p = (void *)vdata; | |
201 | ||
202 | if (IsIPSpoof(source_p)) | |
203 | { | |
204 | source_p->umodes &= ~user_modes['h']; | |
205 | return; | |
206 | } | |
207 | source_p->localClient->mangledhost = MyMalloc(HOSTLEN); | |
208 | if (!irccmp(source_p->orighost, source_p->sockhost)) | |
209 | do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost); | |
210 | else | |
211 | do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost); | |
212 | if (IsDynSpoof(source_p)) | |
213 | source_p->umodes &= ~user_modes['h']; | |
214 | if (source_p->umodes & user_modes['h']) | |
215 | { | |
216 | strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host)); | |
217 | if (irccmp(source_p->host, source_p->orighost)) | |
218 | SetDynSpoof(source_p); | |
219 | } | |
220 | } |