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1 | /* | |
2 | * Charybdis: an advanced ircd | |
3 | * ip_cloaking.c: provide user hostname cloaking | |
4 | * | |
5 | * Written originally by nenolod, altered to use FNV by Elizabeth in 2008 | |
6 | */ | |
7 | ||
8 | #include "stdinc.h" | |
9 | #include "modules.h" | |
10 | #include "hook.h" | |
11 | #include "client.h" | |
12 | #include "ircd.h" | |
13 | #include "send.h" | |
14 | #include "hash.h" | |
15 | #include "s_conf.h" | |
16 | #include "s_user.h" | |
17 | #include "s_serv.h" | |
18 | #include "numeric.h" | |
19 | ||
20 | static int | |
21 | _modinit(void) | |
22 | { | |
23 | /* add the usermode to the available slot */ | |
24 | user_modes['x'] = find_umode_slot(); | |
25 | construct_umodebuf(); | |
26 | ||
27 | return 0; | |
28 | } | |
29 | ||
30 | static void | |
31 | _moddeinit(void) | |
32 | { | |
33 | /* disable the umode and remove it from the available list */ | |
34 | user_modes['x'] = 0; | |
35 | construct_umodebuf(); | |
36 | } | |
37 | ||
38 | static void check_umode_change(void *data); | |
39 | static void check_new_user(void *data); | |
40 | mapi_hfn_list_av1 ip_cloaking_hfnlist[] = { | |
41 | { "umode_changed", (hookfn) check_umode_change }, | |
42 | { "new_local_user", (hookfn) check_new_user }, | |
43 | { NULL, NULL } | |
44 | }; | |
45 | ||
46 | DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL, | |
47 | ip_cloaking_hfnlist, "$Revision: 3526 $"); | |
48 | ||
49 | static void | |
50 | distribute_hostchange(struct Client *client_p, char *newhost) | |
51 | { | |
52 | if (newhost != client_p->orighost) | |
53 | sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host", | |
54 | newhost); | |
55 | else | |
56 | sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset", | |
57 | newhost); | |
58 | ||
59 | sendto_server(NULL, NULL, | |
60 | CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s", | |
61 | use_id(&me), use_id(client_p), newhost); | |
62 | sendto_server(NULL, NULL, | |
63 | CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s", | |
64 | use_id(&me), use_id(client_p), newhost); | |
65 | ||
66 | change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host"); | |
67 | ||
68 | if (newhost != client_p->orighost) | |
69 | SetDynSpoof(client_p); | |
70 | else | |
71 | ClearDynSpoof(client_p); | |
72 | } | |
73 | ||
74 | static void | |
75 | do_host_cloak_ip(const char *inbuf, char *outbuf) | |
76 | { | |
77 | /* None of the characters in this table can be valid in an IP */ | |
78 | char chartable[] = "ghijklmnopqrstuvwxyz"; | |
79 | char *tptr; | |
80 | uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32); | |
81 | int sepcount = 0; | |
82 | int totalcount = 0; | |
83 | int ipv6 = 0; | |
84 | ||
85 | rb_strlcpy(outbuf, inbuf, HOSTLEN + 1); | |
86 | ||
87 | if (strchr(outbuf, ':')) | |
88 | { | |
89 | ipv6 = 1; | |
90 | ||
91 | /* Damn you IPv6... | |
92 | * We count the number of colons so we can calculate how much | |
93 | * of the host to cloak. This is because some hostmasks may not | |
94 | * have as many octets as we'd like. | |
95 | * | |
96 | * We have to do this ahead of time because doing this during | |
97 | * the actual cloaking would get ugly | |
98 | */ | |
99 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
100 | if (*tptr == ':') | |
101 | totalcount++; | |
102 | } | |
103 | else if (!strchr(outbuf, '.')) | |
104 | return; | |
105 | ||
106 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
107 | { | |
108 | if (*tptr == ':' || *tptr == '.') | |
109 | { | |
110 | sepcount++; | |
111 | continue; | |
112 | } | |
113 | ||
114 | if (ipv6 && sepcount < totalcount / 2) | |
115 | continue; | |
116 | ||
117 | if (!ipv6 && sepcount < 2) | |
118 | continue; | |
119 | ||
120 | *tptr = chartable[(*tptr + accum) % 20]; | |
121 | accum = (accum << 1) | (accum >> 31); | |
122 | } | |
123 | } | |
124 | ||
125 | static void | |
126 | do_host_cloak_host(const char *inbuf, char *outbuf) | |
127 | { | |
128 | char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz"; | |
129 | char *tptr; | |
130 | uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32); | |
131 | ||
132 | rb_strlcpy(outbuf, inbuf, HOSTLEN + 1); | |
133 | ||
134 | /* pass 1: scramble first section of hostname using base26 | |
135 | * alphabet toasted against the FNV hash of the string. | |
136 | * | |
137 | * numbers are not changed at this time, only letters. | |
138 | */ | |
139 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
140 | { | |
141 | if (*tptr == '.') | |
142 | break; | |
143 | ||
144 | if (isdigit(*tptr) || *tptr == '-') | |
145 | continue; | |
146 | ||
147 | *tptr = b26_alphabet[(*tptr + accum) % 26]; | |
148 | ||
149 | /* Rotate one bit to avoid all digits being turned odd or even */ | |
150 | accum = (accum << 1) | (accum >> 31); | |
151 | } | |
152 | ||
153 | /* pass 2: scramble each number in the address */ | |
154 | for (tptr = outbuf; *tptr != '\0'; tptr++) | |
155 | { | |
156 | if (isdigit(*tptr)) | |
157 | *tptr = '0' + (*tptr + accum) % 10; | |
158 | ||
159 | accum = (accum << 1) | (accum >> 31); | |
160 | } | |
161 | } | |
162 | ||
163 | static void | |
164 | check_umode_change(void *vdata) | |
165 | { | |
166 | hook_data_umode_changed *data = (hook_data_umode_changed *)vdata; | |
167 | struct Client *source_p = data->client; | |
168 | ||
169 | if (!MyClient(source_p)) | |
170 | return; | |
171 | ||
172 | /* didn't change +h umode, we don't need to do anything */ | |
173 | if (!((data->oldumodes ^ source_p->umodes) & user_modes['x'])) | |
174 | return; | |
175 | ||
176 | if (source_p->umodes & user_modes['x']) | |
177 | { | |
178 | if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost))) | |
179 | { | |
180 | source_p->umodes &= ~user_modes['x']; | |
181 | return; | |
182 | } | |
183 | if (strcmp(source_p->host, source_p->localClient->mangledhost)) | |
184 | { | |
185 | distribute_hostchange(source_p, source_p->localClient->mangledhost); | |
186 | } | |
187 | else /* not really nice, but we need to send this numeric here */ | |
188 | sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host", | |
189 | source_p->host); | |
190 | } | |
191 | else if (!(source_p->umodes & user_modes['x'])) | |
192 | { | |
193 | if (source_p->localClient->mangledhost != NULL && | |
194 | !strcmp(source_p->host, source_p->localClient->mangledhost)) | |
195 | { | |
196 | distribute_hostchange(source_p, source_p->orighost); | |
197 | } | |
198 | } | |
199 | } | |
200 | ||
201 | static void | |
202 | check_new_user(void *vdata) | |
203 | { | |
204 | struct Client *source_p = (void *)vdata; | |
205 | ||
206 | if (IsIPSpoof(source_p)) | |
207 | { | |
208 | source_p->umodes &= ~user_modes['x']; | |
209 | return; | |
210 | } | |
211 | source_p->localClient->mangledhost = rb_malloc(HOSTLEN + 1); | |
212 | if (!irccmp(source_p->orighost, source_p->sockhost)) | |
213 | do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost); | |
214 | else | |
215 | do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost); | |
216 | if (IsDynSpoof(source_p)) | |
217 | source_p->umodes &= ~user_modes['x']; | |
218 | if (source_p->umodes & user_modes['x']) | |
219 | { | |
220 | rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host)); | |
221 | if (irccmp(source_p->host, source_p->orighost)) | |
222 | SetDynSpoof(source_p); | |
223 | } | |
224 | } | |
225 |