Annotation of /trunk/mkinitrd-magellan/busybox/mailutils/sendmail.c
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Revision 984 -
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Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
File MIME type: text/plain
File size: 9100 byte(s)
Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
File MIME type: text/plain
File size: 9100 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | niro | 816 | /* vi: set sw=4 ts=4: */ |
2 | /* | ||
3 | * bare bones sendmail | ||
4 | * | ||
5 | * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com> | ||
6 | * | ||
7 | * Licensed under GPLv2, see file LICENSE in this tarball for details. | ||
8 | */ | ||
9 | #include "libbb.h" | ||
10 | #include "mail.h" | ||
11 | |||
12 | niro | 984 | // limit maximum allowed number of headers to prevent overflows. |
13 | // set to 0 to not limit | ||
14 | #define MAX_HEADERS 256 | ||
15 | |||
16 | niro | 816 | static int smtp_checkp(const char *fmt, const char *param, int code) |
17 | { | ||
18 | char *answer; | ||
19 | const char *msg = command(fmt, param); | ||
20 | // read stdin | ||
21 | // if the string has a form \d\d\d- -- read next string. E.g. EHLO response | ||
22 | // parse first bytes to a number | ||
23 | // if code = -1 then just return this number | ||
24 | // if code != -1 then checks whether the number equals the code | ||
25 | // if not equal -> die saying msg | ||
26 | while ((answer = xmalloc_fgetline(stdin)) != NULL) | ||
27 | if (strlen(answer) <= 3 || '-' != answer[3]) | ||
28 | break; | ||
29 | if (answer) { | ||
30 | int n = atoi(answer); | ||
31 | if (timeout) | ||
32 | alarm(0); | ||
33 | free(answer); | ||
34 | if (-1 == code || n == code) | ||
35 | return n; | ||
36 | } | ||
37 | bb_error_msg_and_die("%s failed", msg); | ||
38 | } | ||
39 | |||
40 | static int smtp_check(const char *fmt, int code) | ||
41 | { | ||
42 | return smtp_checkp(fmt, NULL, code); | ||
43 | } | ||
44 | |||
45 | // strip argument of bad chars | ||
46 | static char *sane_address(char *str) | ||
47 | { | ||
48 | char *s = str; | ||
49 | char *p = s; | ||
50 | while (*s) { | ||
51 | if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) { | ||
52 | *p++ = *s; | ||
53 | } | ||
54 | s++; | ||
55 | } | ||
56 | *p = '\0'; | ||
57 | return str; | ||
58 | } | ||
59 | |||
60 | static void rcptto(const char *s) | ||
61 | { | ||
62 | niro | 984 | // N.B. we don't die if recipient is rejected, for the other recipients may be accepted |
63 | if (250 != smtp_checkp("RCPT TO:<%s>", s, -1)) | ||
64 | bb_error_msg("Bad recipient: <%s>", s); | ||
65 | niro | 816 | } |
66 | |||
67 | int sendmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; | ||
68 | int sendmail_main(int argc UNUSED_PARAM, char **argv) | ||
69 | { | ||
70 | char *opt_connect = opt_connect; | ||
71 | niro | 984 | char *opt_from; |
72 | char *s; | ||
73 | llist_t *list = NULL; | ||
74 | niro | 816 | char *domain = sane_address(safe_getdomainname()); |
75 | niro | 984 | unsigned nheaders = 0; |
76 | niro | 816 | int code; |
77 | |||
78 | enum { | ||
79 | niro | 984 | //--- standard options |
80 | OPT_t = 1 << 0, // read message for recipients, append them to those on cmdline | ||
81 | OPT_f = 1 << 1, // sender address | ||
82 | OPT_o = 1 << 2, // various options. -oi IMPLIED! others are IGNORED! | ||
83 | OPT_i = 1 << 3, // IMPLIED! | ||
84 | //--- BB specific options | ||
85 | OPT_w = 1 << 4, // network timeout | ||
86 | OPT_H = 1 << 5, // use external connection helper | ||
87 | OPT_S = 1 << 6, // specify connection string | ||
88 | OPT_a = 1 << 7, // authentication tokens | ||
89 | niro | 816 | }; |
90 | |||
91 | // init global variables | ||
92 | INIT_G(); | ||
93 | |||
94 | // save initial stdin since body is piped! | ||
95 | xdup2(STDIN_FILENO, 3); | ||
96 | niro | 984 | G.fp0 = xfdopen_for_read(3); |
97 | niro | 816 | |
98 | // parse options | ||
99 | niro | 984 | // -f is required. -H and -S are mutually exclusive |
100 | opt_complementary = "f:w+:H--S:S--H:a::"; | ||
101 | // N.B. since -H and -S are mutually exclusive they do not interfere in opt_connect | ||
102 | // -a is for ssmtp (http://downloads.openwrt.org/people/nico/man/man8/ssmtp.8.html) compatibility, | ||
103 | // it is still under development. | ||
104 | opts = getopt32(argv, "tf:o:iw:H:S:a::", &opt_from, NULL, &timeout, &opt_connect, &opt_connect, &list); | ||
105 | niro | 816 | //argc -= optind; |
106 | argv += optind; | ||
107 | |||
108 | niro | 984 | // process -a[upm]<token> options |
109 | if ((opts & OPT_a) && !list) | ||
110 | bb_show_usage(); | ||
111 | while (list) { | ||
112 | char *a = (char *) llist_pop(&list); | ||
113 | if ('u' == a[0]) | ||
114 | G.user = xstrdup(a+1); | ||
115 | if ('p' == a[0]) | ||
116 | G.pass = xstrdup(a+1); | ||
117 | // N.B. we support only AUTH LOGIN so far | ||
118 | //if ('m' == a[0]) | ||
119 | // G.method = xstrdup(a+1); | ||
120 | } | ||
121 | // N.B. list == NULL here | ||
122 | //bb_info_msg("OPT[%x] AU[%s], AP[%s], AM[%s], ARGV[%s]", opts, au, ap, am, *argv); | ||
123 | |||
124 | niro | 816 | // connect to server |
125 | |||
126 | // connection helper ordered? -> | ||
127 | if (opts & OPT_H) { | ||
128 | const char *args[] = { "sh", "-c", opt_connect, NULL }; | ||
129 | // plug it in | ||
130 | launch_helper(args); | ||
131 | // vanilla connection | ||
132 | niro | 984 | } else { |
133 | niro | 816 | int fd; |
134 | niro | 984 | // host[:port] not explicitly specified? -> use $SMTPHOST |
135 | niro | 816 | // no $SMTPHOST ? -> use localhost |
136 | if (!(opts & OPT_S)) { | ||
137 | opt_connect = getenv("SMTPHOST"); | ||
138 | if (!opt_connect) | ||
139 | opt_connect = (char *)"127.0.0.1"; | ||
140 | } | ||
141 | // do connect | ||
142 | fd = create_and_connect_stream_or_die(opt_connect, 25); | ||
143 | // and make ourselves a simple IO filter | ||
144 | xmove_fd(fd, STDIN_FILENO); | ||
145 | xdup2(STDIN_FILENO, STDOUT_FILENO); | ||
146 | } | ||
147 | // N.B. from now we know nothing about network :) | ||
148 | |||
149 | // wait for initial server OK | ||
150 | // N.B. if we used openssl the initial 220 answer is already swallowed during openssl TLS init procedure | ||
151 | niro | 984 | // so we need to kick the server to see whether we are ok |
152 | niro | 816 | code = smtp_check("NOOP", -1); |
153 | // 220 on plain connection, 250 on openssl-helped TLS session | ||
154 | if (220 == code) | ||
155 | smtp_check(NULL, 250); // reread the code to stay in sync | ||
156 | else if (250 != code) | ||
157 | bb_error_msg_and_die("INIT failed"); | ||
158 | |||
159 | // we should start with modern EHLO | ||
160 | if (250 != smtp_checkp("EHLO %s", domain, -1)) { | ||
161 | smtp_checkp("HELO %s", domain, 250); | ||
162 | } | ||
163 | niro | 984 | if (ENABLE_FEATURE_CLEAN_UP) |
164 | free(domain); | ||
165 | niro | 816 | |
166 | niro | 984 | // perform authentication |
167 | if (opts & OPT_a) { | ||
168 | smtp_check("AUTH LOGIN", 334); | ||
169 | // we must read credentials unless they are given via -a[up] options | ||
170 | if (!G.user || !G.pass) | ||
171 | get_cred_or_die(4); | ||
172 | encode_base64(NULL, G.user, NULL); | ||
173 | smtp_check("", 334); | ||
174 | encode_base64(NULL, G.pass, NULL); | ||
175 | smtp_check("", 235); | ||
176 | } | ||
177 | |||
178 | niro | 816 | // set sender |
179 | // N.B. we have here a very loosely defined algotythm | ||
180 | // since sendmail historically offers no means to specify secrets on cmdline. | ||
181 | // 1) server can require no authentication -> | ||
182 | // we must just provide a (possibly fake) reply address. | ||
183 | // 2) server can require AUTH -> | ||
184 | // we must provide valid username and password along with a (possibly fake) reply address. | ||
185 | // For the sake of security username and password are to be read either from console or from a secured file. | ||
186 | // Since reading from console may defeat usability, the solution is either to read from a predefined | ||
187 | // file descriptor (e.g. 4), or again from a secured file. | ||
188 | |||
189 | // got no sender address? -> use system username as a resort | ||
190 | niro | 984 | // N.B. we marked -f as required option! |
191 | //if (!G.user) { | ||
192 | // // N.B. IMHO getenv("USER") can be way easily spoofed! | ||
193 | // G.user = xuid2uname(getuid()); | ||
194 | // opt_from = xasprintf("%s@%s", G.user, domain); | ||
195 | //} | ||
196 | //if (ENABLE_FEATURE_CLEAN_UP) | ||
197 | // free(domain); | ||
198 | smtp_checkp("MAIL FROM:<%s>", opt_from, 250); | ||
199 | niro | 816 | |
200 | niro | 984 | // process message |
201 | niro | 816 | |
202 | niro | 984 | // read recipients from message and add them to those given on cmdline. |
203 | // this means we scan stdin for To:, Cc:, Bcc: lines until an empty line | ||
204 | // and then use the rest of stdin as message body | ||
205 | code = 0; // set "analyze headers" mode | ||
206 | while ((s = xmalloc_fgetline(G.fp0)) != NULL) { | ||
207 | dump: | ||
208 | // put message lines doubling leading dots | ||
209 | if (code) { | ||
210 | niro | 816 | // escape leading dots |
211 | // N.B. this feature is implied even if no -i (-oi) switch given | ||
212 | // N.B. we need to escape the leading dot regardless of | ||
213 | // whether it is single or not character on the line | ||
214 | if ('.' == s[0] /*&& '\0' == s[1] */) | ||
215 | printf("."); | ||
216 | // dump read line | ||
217 | printf("%s\r\n", s); | ||
218 | niro | 984 | free(s); |
219 | continue; | ||
220 | niro | 816 | } |
221 | niro | 984 | |
222 | // analyze headers | ||
223 | // To: or Cc: headers add recipients | ||
224 | if (0 == strncasecmp("To: ", s, 4) || 0 == strncasecmp("Bcc: " + 1, s, 4)) { | ||
225 | rcptto(sane_address(s+4)); | ||
226 | goto addheader; | ||
227 | // Bcc: header adds blind copy (hidden) recipient | ||
228 | } else if (0 == strncasecmp("Bcc: ", s, 5)) { | ||
229 | rcptto(sane_address(s+5)); | ||
230 | free(s); | ||
231 | // N.B. Bcc: vanishes from headers! | ||
232 | |||
233 | // other headers go verbatim | ||
234 | |||
235 | // N.B. RFC2822 2.2.3 "Long Header Fields" allows for headers to occupy several lines. | ||
236 | // Continuation is denoted by prefixing additional lines with whitespace(s). | ||
237 | // Thanks (stefan.seyfried at googlemail.com) for pointing this out. | ||
238 | } else if (strchr(s, ':') || (list && skip_whitespace(s) != s)) { | ||
239 | addheader: | ||
240 | // N.B. we allow MAX_HEADERS generic headers at most to prevent attacks | ||
241 | if (MAX_HEADERS && ++nheaders >= MAX_HEADERS) | ||
242 | goto bail; | ||
243 | llist_add_to_end(&list, s); | ||
244 | // a line without ":" (an empty line too, by definition) doesn't look like a valid header | ||
245 | // so stop "analyze headers" mode | ||
246 | } else { | ||
247 | reenter: | ||
248 | // put recipients specified on cmdline | ||
249 | while (*argv) { | ||
250 | char *t = sane_address(*argv); | ||
251 | rcptto(t); | ||
252 | //if (MAX_HEADERS && ++nheaders >= MAX_HEADERS) | ||
253 | // goto bail; | ||
254 | llist_add_to_end(&list, xasprintf("To: %s", t)); | ||
255 | argv++; | ||
256 | } | ||
257 | // enter "put message" mode | ||
258 | // N.B. DATA fails iff no recipients were accepted (or even provided) | ||
259 | // in this case just bail out gracefully | ||
260 | if (354 != smtp_check("DATA", -1)) | ||
261 | goto bail; | ||
262 | // dump the headers | ||
263 | while (list) { | ||
264 | printf("%s\r\n", (char *) llist_pop(&list)); | ||
265 | } | ||
266 | // stop analyzing headers | ||
267 | code++; | ||
268 | // N.B. !s means: we read nothing, and nothing to be read in the future. | ||
269 | // just dump empty line and break the loop | ||
270 | if (!s) { | ||
271 | puts("\r"); | ||
272 | break; | ||
273 | } | ||
274 | // go dump message body | ||
275 | // N.B. "s" already contains the first non-header line, so pretend we read it from input | ||
276 | goto dump; | ||
277 | } | ||
278 | niro | 816 | } |
279 | niro | 984 | // odd case: we didn't stop "analyze headers" mode -> message body is empty. Reenter the loop |
280 | // N.B. after reenter code will be > 0 | ||
281 | if (!code) | ||
282 | goto reenter; | ||
283 | niro | 816 | |
284 | niro | 984 | // finalize the message |
285 | niro | 816 | smtp_check(".", 250); |
286 | niro | 984 | bail: |
287 | niro | 816 | // ... and say goodbye |
288 | smtp_check("QUIT", 221); | ||
289 | // cleanup | ||
290 | if (ENABLE_FEATURE_CLEAN_UP) | ||
291 | fclose(G.fp0); | ||
292 | |||
293 | return EXIT_SUCCESS; | ||
294 | } |