smtp.c

   1 /*
   2  * a simple smtp mail sender
   3  *
   4  * Copyright (C) 2010 Ali Gholami Rudi
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, as published by the
   8  * Free Software Foundation.
   9  */
  10 #include <arpa/inet.h>
  11 #include <ctype.h>
  12 #include <errno.h>
  13 #include <fcntl.h>
  14 #include <netdb.h>
  15 #include <netinet/in.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <strings.h>
  20 #include <sys/socket.h>
  21 #include <sys/stat.h>
  22 #include <sys/types.h>
  23 #include <time.h>
  24 #include <unistd.h>
  25 #include "config.h"
  26
  27 #define BUFFSIZE                (1 << 12)
  28 #define ARRAY_SIZE(a)           (sizeof(a) / sizeof((a)[0]))
  29 #define MIN(a, b)               ((a) < (b) ? (a) : (b))
  30
  31 static char buf[BUFFSIZE];
  32 static char *buf_cur;
  33 static char *buf_end;
  34 static int fd;
  35 static char mail[MAILLEN];
  36 static int mail_len;
  37
  38 #ifdef SSL
  39 #include <polarssl/ssl.h>
  40 #include <polarssl/havege.h>
  41
  42 static ssl_context ssl;
  43 static ssl_session ssn;
  44 static havege_state hs;
  45
  46 static int ps_send(void *ctx, unsigned char *buf, int len)
  47 {
  48         return write(*(int *) ctx, buf, len);
  49 }
  50
  51 static int ps_recv(void *ctx, unsigned char *buf, int len)
  52 {
  53         return read(*(int *) ctx, buf, len);
  54 }
  55
  56 #endif
  57
  58 static char *b64 =
  59         "ABCDEFGHIJGLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  60
  61 static void b64_num(char *s, unsigned long num)
  62 {
  63         s[3] = b64[num & 0x3f];
  64         num >>= 6;
  65         s[2] = b64[num & 0x3f];
  66         num >>= 6;
  67         s[1] = b64[num & 0x3f];
  68         num >>= 6;
  69         s[0] = b64[num & 0x3f];
  70 }
  71
  72 static char *putb64(char *dst, char *src, int len)
  73 {
  74         int n = len / 3;
  75         int i;
  76         if (n * 3 != len)
  77                 n++;
  78         for (i = 0; i < n; i++) {
  79                 char *s = src + 3 * i;
  80                 unsigned c0 = (unsigned) s[0];
  81                 unsigned c1 = s + 1 < src + len ? (unsigned) s[1] : 0;
  82                 unsigned c2 = s + 2 < src + len ? (unsigned) s[2] : 0;
  83                 unsigned long word = (c0 << 16) | (c1 << 8) | c2;
  84                 b64_num(dst + 4 * i, word);
  85         }
  86         if (len % 3)
  87                 for (i = len % 3; i < 3; i++)
  88                         dst[4 * len - 3 + i] = '=';
  89         dst[n * 4] = '\0';
  90         return dst + n * 4;
  91 }
  92
  93 static char *putstr(char *dst, char *src)
  94 {
  95         int len = strchr(src, '\0') - src;
  96         memcpy(dst, src, len + 1);
  97         return dst + len;
  98 }
  99
 100 static char *cutaddr(char *dst, char *s, int len)
 101 {
 102         static char *addrseps = "<>()%!~* \t\r\n,\"'%";
 103         char *end = s + len;
 104         while (s < end && *s && strchr(addrseps, *s))
 105                 s++;
 106         while (s < end && *s && !strchr(addrseps, *s))
 107                 *dst++ = *s++;
 108         *dst = '\0';
 109         return s;
 110 }
 111
 112 static char *find_hdr(char *hdr)
 113 {
 114         char *s = mail;
 115         int len = strlen(hdr);
 116         char *end = mail + mail_len - len;
 117         while (s < end) {
 118                 char *r;
 119                 if (!strncasecmp(s, hdr, len))
 120                         return s;
 121                 r = memchr(s, '\n', end - s);
 122                 if (!r || r == s)
 123                         return NULL;
 124                 s = r + 1;
 125         }
 126         return s;
 127 }
 128
 129 static int hdr_len(char *hdr)
 130 {
 131         char *s = hdr;
 132         while (*s) {
 133                 char *r = strchr(s, '\n');
 134                 if (!r)
 135                         return strchr(s, '\0') - hdr;
 136                 s = r + 1;
 137                 if (!isspace(*s))
 138                         return s - hdr;
 139         }
 140         return 0;
 141 }
 142
 143 static int xread(int fd, char *buf, int len)
 144 {
 145         int nr = 0;
 146         while (nr < len) {
 147                 int ret = read(fd, buf + nr, len - nr);
 148                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
 149                         continue;
 150                 if (ret <= 0)
 151                         break;
 152                 nr += ret;
 153         }
 154         return nr;
 155 }
 156
 157 static void print(char *buf, int len)
 158 {
 159         write(STDOUT_FILENO, buf, len);
 160 }
 161
 162 static int smtp_connect(char *addr, char *port)
 163 {
 164         struct addrinfo hints, *addrinfo;
 165         int fd;
 166
 167         memset(&hints, 0, sizeof(hints));
 168         hints.ai_family = AF_UNSPEC;
 169         hints.ai_socktype = SOCK_STREAM;
 170         hints.ai_flags = AI_PASSIVE;
 171
 172         getaddrinfo(addr, port, &hints, &addrinfo);
 173         fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
 174                         addrinfo->ai_protocol);
 175
 176         if (connect(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) == -1) {
 177                 close(fd);
 178                 freeaddrinfo(addrinfo);
 179                 return -1;
 180         }
 181         freeaddrinfo(addrinfo);
 182         return fd;
 183 }
 184
 185 static int reply_line(char *dst, int len)
 186 {
 187         int nr = 0;
 188         char *nl;
 189         while (nr < len) {
 190                 int ml;
 191                 if (!buf_cur || buf_cur >= buf_end) {
 192 #ifdef SSL
 193                         int buf_len = ssl_read(&ssl, (unsigned char *) buf,
 194                                                 sizeof(buf));
 195 #else
 196                         int buf_len = read(fd, buf, sizeof(buf));
 197 #endif
 198                         if (buf_len <= 0)
 199                                 return -1;
 200 #ifdef DEBUG
 201                         print(buf, buf_len);
 202 #endif
 203                         buf_cur = buf;
 204                         buf_end = buf + buf_len;
 205                 }
 206                 ml = MIN(buf_end - buf_cur, len - nr);
 207                 if ((nl = memchr(buf_cur, '\n', ml))) {
 208                         nl++;
 209                         memcpy(dst + nr, buf_cur, nl - buf_cur);
 210                         nr += nl - buf_cur;
 211                         buf_cur = nl;
 212                         return nr;
 213                 }
 214                 memcpy(dst + nr, buf_cur, ml);
 215                 nr += ml;
 216                 buf_cur += ml;
 217         }
 218         return nr;
 219 }
 220
 221 static int smtp_write(char *s, int len)
 222 {
 223 #ifdef DEBUG
 224         print(s, len);
 225 #endif
 226 #ifdef SSL
 227         return ssl_write(&ssl, (unsigned char *) s, len);
 228 #else
 229         return write(fd, s, len);
 230 #endif
 231 }
 232
 233 static int smtp_xwrite(char *buf, int len)
 234 {
 235         int nw = 0;
 236         while (nw < len) {
 237                 int ret = smtp_write(buf + nw, len - nw);
 238                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
 239                         continue;
 240                 if (ret < 0)
 241                         break;
 242                 nw += ret;
 243         }
 244         fsync(fd);
 245         return nw;
 246 }
 247
 248 static void send_cmd(char *cmd)
 249 {
 250         smtp_write(cmd, strlen(cmd));
 251 }
 252
 253 static int is_eoc(char *s, int len)
 254 {
 255         return isdigit(s[0]) && isdigit(s[1]) && isdigit(s[2]) && isspace(s[3]);
 256 }
 257
 258 static void ehlo(void)
 259 {
 260         char line[BUFFSIZE];
 261         int len;
 262         len = reply_line(line, sizeof(line));
 263         send_cmd("EHLO " HOSTNAME "\r\n");
 264         do {
 265                 len = reply_line(line, sizeof(line));
 266         } while (!is_eoc(line, len));
 267 }
 268
 269 static void login(char *user, char *pass)
 270 {
 271         char line[BUFFSIZE];
 272         int len;
 273         char *s = line;
 274         send_cmd("AUTH LOGIN\r\n");
 275         len = reply_line(line, sizeof(line));
 276         s = putb64(s, user, strlen(user));
 277         s = putstr(s, "\r\n");
 278         send_cmd(line);
 279         len = reply_line(line, sizeof(line));
 280         s = line;
 281         s = putb64(s, pass, strlen(pass));
 282         s = putstr(s, "\r\n");
 283         send_cmd(line);
 284         len = reply_line(line, sizeof(line));
 285 }
 286
 287 static int write_mail(struct account *account)
 288 {
 289         char line[BUFFSIZE];
 290         int len;
 291         char *s = line;
 292         char *to_hdrs[] = {"to:", "cc:", "bcc:"};
 293         int i;
 294         s = putstr(s, "MAIL FROM:<");
 295         s = putstr(s, account->from);
 296         s = putstr(s, ">\r\n");
 297         send_cmd(line);
 298         len = reply_line(line, sizeof(line));
 299
 300         for (i = 0; i < ARRAY_SIZE(to_hdrs); i++) {
 301                 char *hdr, *end;
 302                 char addr[BUFFSIZE];
 303                 if (!(hdr = find_hdr(to_hdrs[i])))
 304                         continue;
 305                 end = hdr + hdr_len(hdr);
 306                 s = hdr;
 307                 while ((s = cutaddr(addr, s, end - s)) && s < end) {
 308                         char *at = strchr(addr, '@');
 309                         if (at && at > addr && *(at + 1)) {
 310                                 char *r = line;
 311                                 r = putstr(r, "RCPT TO:<");
 312                                 r = putstr(r, addr);
 313                                 r = putstr(r, ">\r\n");
 314                                 send_cmd(line);
 315                                 len = reply_line(line, sizeof(line));
 316                         }
 317                 }
 318         }
 319
 320         send_cmd("DATA\r\n");
 321         len = reply_line(line, sizeof(line));
 322         if (smtp_xwrite(mail, mail_len) != mail_len)
 323                 return -1;
 324         send_cmd("\r\n.\r\n");
 325         len = reply_line(line, sizeof(line));
 326         send_cmd("QUIT\r\n");
 327         len = reply_line(line, sizeof(line));
 328         return 0;
 329 }
 330
 331 static struct account *choose_account(void)
 332 {
 333         char *from = find_hdr("from:");
 334         char *end = from + hdr_len(from);
 335         int i;
 336         if (!from)
 337                 return &accounts[0];
 338         for (i = 0; i < ARRAY_SIZE(accounts); i++) {
 339                 char *pat = accounts[i].from;
 340                 int len = strlen(pat);
 341                 char *s = from;
 342                 while (s + len < end && (s = memchr(s, pat[0], end - s)))
 343                         if (!strncmp(pat, s++, len))
 344                                 return &accounts[i];
 345         }
 346         return &accounts[0];
 347 }
 348
 349 int main(int argc, char *argv[])
 350 {
 351         struct account *account;
 352         if ((mail_len = xread(STDIN_FILENO, mail, sizeof(mail))) == -1)
 353                 return 1;
 354         account = choose_account();
 355         fd = smtp_connect(account->server, account->port);
 356 #ifdef SSL
 357         havege_init(&hs);
 358         memset(&ssn, 0, sizeof(ssn));
 359         if (ssl_init(&ssl))
 360                 return 1;
 361         ssl_set_endpoint(&ssl, SSL_IS_CLIENT);
 362         ssl_set_authmode(&ssl, SSL_VERIFY_NONE);
 363         ssl_set_rng(&ssl, havege_rand, &hs);
 364         ssl_set_bio(&ssl, ps_recv, &fd, ps_send, &fd);
 365         ssl_set_ciphers(&ssl, ssl_default_ciphers);
 366         ssl_set_session(&ssl, 1, 600, &ssn);
 367 #endif
 368         ehlo();
 369         login(account->user, account->pass);
 370         write_mail(account);
 371
 372 #ifdef SSL
 373         ssl_close_notify(&ssl);
 374 #endif
 375         close(fd);
 376 #ifdef SSL
 377         ssl_free(&ssl);
 378 #endif
 379         return 0;
 380 }