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0756eb3c PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
3386088d | 5 | /* Copyright (c) University of Cambridge 1995 - 2015 */ |
0756eb3c PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | #include "../exim.h" | |
9 | #include "plaintext.h" | |
10 | ||
11 | ||
12 | /* Options specific to the plaintext authentication mechanism. */ | |
13 | ||
14 | optionlist auth_plaintext_options[] = { | |
4730f942 PH |
15 | { "client_ignore_invalid_base64", opt_bool, |
16 | (void *)(offsetof(auth_plaintext_options_block, client_ignore_invalid_base64)) }, | |
0756eb3c PH |
17 | { "client_send", opt_stringptr, |
18 | (void *)(offsetof(auth_plaintext_options_block, client_send)) }, | |
0756eb3c PH |
19 | { "server_prompts", opt_stringptr, |
20 | (void *)(offsetof(auth_plaintext_options_block, server_prompts)) } | |
21 | }; | |
22 | ||
23 | /* Size of the options list. An extern variable has to be used so that its | |
24 | address can appear in the tables drtables.c. */ | |
25 | ||
26 | int auth_plaintext_options_count = | |
27 | sizeof(auth_plaintext_options)/sizeof(optionlist); | |
28 | ||
29 | /* Default private options block for the plaintext authentication method. */ | |
30 | ||
31 | auth_plaintext_options_block auth_plaintext_option_defaults = { | |
0756eb3c | 32 | NULL, /* server_prompts */ |
4730f942 PH |
33 | NULL, /* client_send */ |
34 | FALSE /* client_ignore_invalid_base64 */ | |
0756eb3c PH |
35 | }; |
36 | ||
37 | ||
d185889f JH |
38 | #ifdef MACRO_PREDEF |
39 | ||
40 | /* Dummy values */ | |
41 | void auth_plaintext_init(auth_instance *ablock) {} | |
42 | int auth_plaintext_server(auth_instance *ablock, uschar *data) {return 0;} | |
43 | int auth_plaintext_client(auth_instance *ablock, smtp_inblock *inblock, | |
44 | smtp_outblock *outblock, int timeout, uschar *buffer, int buffsize) {return 0;} | |
45 | ||
46 | #else /*!MACRO_PREDEF*/ | |
47 | ||
48 | ||
49 | ||
0756eb3c PH |
50 | /************************************************* |
51 | * Initialization entry point * | |
52 | *************************************************/ | |
53 | ||
54 | /* Called for each instance, after its options have been read, to | |
55 | enable consistency checks to be done, or anything else that needs | |
56 | to be set up. */ | |
57 | ||
58 | void | |
59 | auth_plaintext_init(auth_instance *ablock) | |
60 | { | |
61 | auth_plaintext_options_block *ob = | |
62 | (auth_plaintext_options_block *)(ablock->options_block); | |
63 | if (ablock->public_name == NULL) ablock->public_name = ablock->name; | |
16ff981e | 64 | if (ablock->server_condition != NULL) ablock->server = TRUE; |
0756eb3c PH |
65 | if (ob->client_send != NULL) ablock->client = TRUE; |
66 | } | |
67 | ||
68 | ||
69 | ||
70 | /************************************************* | |
71 | * Server entry point * | |
72 | *************************************************/ | |
73 | ||
74 | /* For interface, see auths/README */ | |
75 | ||
76 | int | |
77 | auth_plaintext_server(auth_instance *ablock, uschar *data) | |
78 | { | |
79 | auth_plaintext_options_block *ob = | |
80 | (auth_plaintext_options_block *)(ablock->options_block); | |
55414b25 | 81 | const uschar *prompts = ob->server_prompts; |
16ff981e | 82 | uschar *clear, *end, *s; |
0756eb3c PH |
83 | int number = 1; |
84 | int len, rc; | |
85 | int sep = 0; | |
86 | ||
87 | /* Expand a non-empty list of prompt strings */ | |
88 | ||
89 | if (prompts != NULL) | |
90 | { | |
55414b25 | 91 | prompts = expand_cstring(prompts); |
0756eb3c PH |
92 | if (prompts == NULL) |
93 | { | |
94 | auth_defer_msg = expand_string_message; | |
95 | return DEFER; | |
96 | } | |
97 | } | |
98 | ||
99 | /* If data was supplied on the AUTH command, decode it, and split it up into | |
f78eb7c6 PH |
100 | multiple items at binary zeros. The strings are put into $auth1, $auth2, etc, |
101 | up to a maximum. To retain backwards compatibility, they are also put int $1, | |
102 | $2, etc. If the data consists of the string "=" it indicates a single, empty | |
103 | string. */ | |
0756eb3c PH |
104 | |
105 | if (*data != 0) | |
106 | { | |
107 | if (Ustrcmp(data, "=") == 0) | |
108 | { | |
f78eb7c6 | 109 | auth_vars[0] = expand_nstring[++expand_nmax] = US""; |
0756eb3c PH |
110 | expand_nlength[expand_nmax] = 0; |
111 | } | |
112 | else | |
113 | { | |
f4d091fb | 114 | if ((len = b64decode(data, &clear)) < 0) return BAD64; |
0756eb3c PH |
115 | end = clear + len; |
116 | while (clear < end && expand_nmax < EXPAND_MAXN) | |
117 | { | |
f78eb7c6 | 118 | if (expand_nmax < AUTH_VARS) auth_vars[expand_nmax] = clear; |
0756eb3c PH |
119 | expand_nstring[++expand_nmax] = clear; |
120 | while (*clear != 0) clear++; | |
121 | expand_nlength[expand_nmax] = clear++ - expand_nstring[expand_nmax]; | |
122 | } | |
123 | } | |
124 | } | |
125 | ||
126 | /* Now go through the list of prompt strings. Skip over any whose data has | |
127 | already been provided as part of the AUTH command. For the rest, send them | |
128 | out as prompts, and get a data item back. If the data item is "*", abandon the | |
129 | authentication attempt. Otherwise, split it into items as above. */ | |
130 | ||
131 | while ((s = string_nextinlist(&prompts, &sep, big_buffer, big_buffer_size)) | |
132 | != NULL && expand_nmax < EXPAND_MAXN) | |
133 | { | |
134 | if (number++ <= expand_nmax) continue; | |
135 | if ((rc = auth_get_data(&data, s, Ustrlen(s))) != OK) return rc; | |
f4d091fb | 136 | if ((len = b64decode(data, &clear)) < 0) return BAD64; |
0756eb3c PH |
137 | end = clear + len; |
138 | ||
139 | /* This loop must run at least once, in case the length is zero */ | |
140 | do | |
141 | { | |
f78eb7c6 | 142 | if (expand_nmax < AUTH_VARS) auth_vars[expand_nmax] = clear; |
0756eb3c PH |
143 | expand_nstring[++expand_nmax] = clear; |
144 | while (*clear != 0) clear++; | |
145 | expand_nlength[expand_nmax] = clear++ - expand_nstring[expand_nmax]; | |
146 | } | |
147 | while (clear < end && expand_nmax < EXPAND_MAXN); | |
148 | } | |
149 | ||
f78eb7c6 | 150 | /* We now have a number of items of data in $auth1, $auth2, etc (and also, for |
16ff981e PH |
151 | compatibility, in $1, $2, etc). Authentication and authorization are handled |
152 | together for this authenticator by expanding the server_condition option. Note | |
153 | that ablock->server_condition is always non-NULL because that's what configures | |
154 | this authenticator as a server. */ | |
0756eb3c | 155 | |
16ff981e | 156 | return auth_check_serv_cond(ablock); |
0756eb3c PH |
157 | } |
158 | ||
159 | ||
160 | ||
161 | /************************************************* | |
162 | * Client entry point * | |
163 | *************************************************/ | |
164 | ||
165 | /* For interface, see auths/README */ | |
166 | ||
167 | int | |
168 | auth_plaintext_client( | |
169 | auth_instance *ablock, /* authenticator block */ | |
170 | smtp_inblock *inblock, /* connection inblock */ | |
171 | smtp_outblock *outblock, /* connection outblock */ | |
172 | int timeout, /* command timeout */ | |
173 | uschar *buffer, /* buffer for reading response */ | |
174 | int buffsize) /* size of buffer */ | |
175 | { | |
176 | auth_plaintext_options_block *ob = | |
177 | (auth_plaintext_options_block *)(ablock->options_block); | |
55414b25 | 178 | const uschar *text = ob->client_send; |
0756eb3c PH |
179 | uschar *s; |
180 | BOOL first = TRUE; | |
181 | int sep = 0; | |
4730f942 | 182 | int auth_var_idx = 0; |
0756eb3c PH |
183 | |
184 | /* The text is broken up into a number of different data items, which are | |
185 | sent one by one. The first one is sent with the AUTH command; the remainder are | |
186 | sent in response to subsequent prompts. Each is expanded before being sent. */ | |
187 | ||
4e910c01 | 188 | while ((s = string_nextinlist(&text, &sep, big_buffer, big_buffer_size))) |
0756eb3c | 189 | { |
4730f942 | 190 | int i, len, clear_len; |
0756eb3c | 191 | uschar *ss = expand_string(s); |
4730f942 | 192 | uschar *clear; |
0756eb3c PH |
193 | |
194 | /* Forced expansion failure is not an error; authentication is abandoned. On | |
195 | all but the first string, we have to abandon the authentication attempt by | |
196 | sending a line containing "*". Save the failed expansion string, because it | |
197 | is in big_buffer, and that gets used by the sending function. */ | |
198 | ||
4e910c01 | 199 | if (!ss) |
0756eb3c PH |
200 | { |
201 | uschar *ssave = string_copy(s); | |
202 | if (!first) | |
203 | { | |
4e910c01 | 204 | if (smtp_write_command(outblock, SCMD_FLUSH, "*\r\n") >= 0) |
0756eb3c PH |
205 | (void) smtp_read_response(inblock, US buffer, buffsize, '2', timeout); |
206 | } | |
4730f942 PH |
207 | if (expand_string_forcedfail) |
208 | { | |
209 | *buffer = 0; /* No message */ | |
210 | return CANCELLED; | |
211 | } | |
0756eb3c PH |
212 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
213 | "authenticator: %s", ssave, ablock->name, expand_string_message); | |
214 | return ERROR; | |
215 | } | |
216 | ||
217 | len = Ustrlen(ss); | |
218 | ||
219 | /* The character ^ is used as an escape for a binary zero character, which is | |
220 | needed for the PLAIN mechanism. It must be doubled if really needed. */ | |
221 | ||
222 | for (i = 0; i < len; i++) | |
0756eb3c | 223 | if (ss[i] == '^') |
4e910c01 JH |
224 | if (ss[i+1] != '^') |
225 | ss[i] = 0; | |
226 | else | |
0756eb3c PH |
227 | { |
228 | i++; | |
229 | len--; | |
230 | memmove(ss + i, ss + i + 1, len - i); | |
231 | } | |
0756eb3c PH |
232 | |
233 | /* The first string is attached to the AUTH command; others are sent | |
4c04137d | 234 | unembellished. */ |
0756eb3c PH |
235 | |
236 | if (first) | |
237 | { | |
238 | first = FALSE; | |
4e910c01 | 239 | if (smtp_write_command(outblock, SCMD_FLUSH, "AUTH %s%s%s\r\n", |
0756eb3c | 240 | ablock->public_name, (len == 0)? "" : " ", |
f4d091fb | 241 | b64encode(ss, len)) < 0) |
0756eb3c PH |
242 | return FAIL_SEND; |
243 | } | |
244 | else | |
245 | { | |
4e910c01 | 246 | if (smtp_write_command(outblock, SCMD_FLUSH, "%s\r\n", |
f4d091fb | 247 | b64encode(ss, len)) < 0) |
0756eb3c PH |
248 | return FAIL_SEND; |
249 | } | |
250 | ||
251 | /* If we receive a success response from the server, authentication | |
252 | has succeeded. There may be more data to send, but is there any point | |
253 | in provoking an error here? */ | |
254 | ||
255 | if (smtp_read_response(inblock, US buffer, buffsize, '2', timeout)) return OK; | |
256 | ||
257 | /* Not a success response. If errno != 0 there is some kind of transmission | |
258 | error. Otherwise, check the response code in the buffer. If it starts with | |
259 | '3', more data is expected. */ | |
260 | ||
261 | if (errno != 0 || buffer[0] != '3') return FAIL; | |
262 | ||
263 | /* If there is no more data to send, we have to cancel the authentication | |
264 | exchange and return ERROR. */ | |
265 | ||
266 | if (text == NULL) | |
267 | { | |
4e910c01 | 268 | if (smtp_write_command(outblock, SCMD_FLUSH, "*\r\n") >= 0) |
0756eb3c PH |
269 | (void)smtp_read_response(inblock, US buffer, buffsize, '2', timeout); |
270 | string_format(buffer, buffsize, "Too few items in client_send in %s " | |
271 | "authenticator", ablock->name); | |
272 | return ERROR; | |
273 | } | |
4730f942 PH |
274 | |
275 | /* Now that we know we'll continue, we put the received data into $auth<n>, | |
276 | if possible. First, decode it: buffer+4 skips over the SMTP status code. */ | |
277 | ||
f4d091fb | 278 | clear_len = b64decode(buffer+4, &clear); |
4730f942 PH |
279 | |
280 | /* If decoding failed, the default is to terminate the authentication, and | |
281 | return FAIL, with the SMTP response still in the buffer. However, if client_ | |
282 | ignore_invalid_base64 is set, we ignore the error, and put an empty string | |
283 | into $auth<n>. */ | |
284 | ||
285 | if (clear_len < 0) | |
286 | { | |
287 | uschar *save_bad = string_copy(buffer); | |
288 | if (!ob->client_ignore_invalid_base64) | |
289 | { | |
4e910c01 | 290 | if (smtp_write_command(outblock, SCMD_FLUSH, "*\r\n") >= 0) |
4730f942 PH |
291 | (void)smtp_read_response(inblock, US buffer, buffsize, '2', timeout); |
292 | string_format(buffer, buffsize, "Invalid base64 string in server " | |
293 | "response \"%s\"", save_bad); | |
294 | return CANCELLED; | |
295 | } | |
296 | clear = US""; | |
297 | clear_len = 0; | |
298 | } | |
299 | ||
300 | if (auth_var_idx < AUTH_VARS) | |
301 | auth_vars[auth_var_idx++] = string_copy(clear); | |
0756eb3c PH |
302 | } |
303 | ||
304 | /* Control should never actually get here. */ | |
305 | ||
306 | return FAIL; | |
307 | } | |
308 | ||
d185889f | 309 | #endif /*!MACRO_PREDEF*/ |
0756eb3c | 310 | /* End of plaintext.c */ |