src/src/srs.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* SRS - Sender rewriting scheme support
   6   (C)2004 Miles Wilton <miles@mirtol.com>
   7
   8   SRS Support Version: 1.0a
   9
  10   License: GPL */
  11
  12 #include "exim.h"
  13 #ifdef EXPERIMENTAL_SRS
  14
  15 #include <srs_alt.h>
  16 #include "srs.h"
  17
  18 srs_t    *srs                   = NULL;
  19 uschar   *srs_db_forward        = NULL;
  20 uschar   *srs_db_reverse        = NULL;
  21
  22
  23 /* srs_init just initialises libsrs and creates (if necessary)
  24    an srs object to use for all srs calls in this instance */
  25
  26 int eximsrs_init()
  27 {
  28   uschar *list = srs_config;
  29   uschar secret_buf[SRS_MAX_SECRET_LENGTH];
  30   uschar *secret = NULL;
  31   uschar sbuf[4];
  32   uschar *sbufp;
  33
  34   /* Check if this instance of Exim has not initialized SRS */
  35   if(srs == NULL)
  36   {
  37     int co = 0;
  38     int hashlen, maxage;
  39     BOOL usetimestamp, usehash;
  40
  41     /* Copy config vars */
  42     hashlen = srs_hashlength;
  43     maxage = srs_maxage;
  44     usetimestamp = srs_usetimestamp;
  45     usehash = srs_usehash;
  46
  47     /* Pass srs_config var (overrides new config vars) */
  48     co = 0;
  49     if(srs_config != NULL)
  50     {
  51       secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH);
  52
  53       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  54         maxage = atoi(sbuf);
  55
  56       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  57         hashlen = atoi(sbuf);
  58
  59       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  60         usetimestamp = atoi(sbuf);
  61
  62       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  63         usehash = atoi(sbuf);
  64     }
  65
  66     if(srs_hashmin == -1)
  67       srs_hashmin = hashlen;
  68
  69     /* First secret specified in secrets? */
  70     co = 0;
  71     list = srs_secrets;
  72     if(secret == NULL || *secret == '\0')
  73     {
  74       if((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) == NULL)
  75       {
  76         log_write(0, LOG_MAIN | LOG_PANIC,
  77             "SRS Configuration Error: No secret specified");
  78         return DEFER;
  79       }
  80     }
  81
  82     /* Check config */
  83     if(maxage < 0 || maxage > 365)
  84     {
  85       log_write(0, LOG_MAIN | LOG_PANIC,
  86           "SRS Configuration Error: Invalid maximum timestamp age");
  87       return DEFER;
  88     }
  89     if(hashlen < 1 || hashlen > 20 || srs_hashmin < 1 || srs_hashmin > 20)
  90     {
  91       log_write(0, LOG_MAIN | LOG_PANIC,
  92           "SRS Configuration Error: Invalid hash length");
  93       return DEFER;
  94     }
  95
  96     if((srs = srs_open(secret, Ustrlen(secret), maxage, hashlen, srs_hashmin)) == NULL)
  97     {
  98       log_write(0, LOG_MAIN | LOG_PANIC,
  99           "Failed to allocate SRS memory");
 100       return DEFER;
 101     }
 102
 103     srs_set_option(srs, SRS_OPTION_USETIMESTAMP, usetimestamp);
 104     srs_set_option(srs, SRS_OPTION_USEHASH, usehash);
 105
 106     /* Extra secrets? */
 107     while((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) != NULL)
 108         srs_add_secret(srs, secret, (Ustrlen(secret) > SRS_MAX_SECRET_LENGTH) ? SRS_MAX_SECRET_LENGTH :  Ustrlen(secret));
 109
 110     DEBUG(D_any)
 111       debug_printf("SRS initialized\n");
 112   }
 113
 114   return OK;
 115 }
 116
 117
 118 int eximsrs_done()
 119 {
 120   if(srs != NULL)
 121     srs_close(srs);
 122
 123   srs = NULL;
 124
 125   return OK;
 126 }
 127
 128
 129 int eximsrs_forward(uschar **result, uschar *orig_sender, uschar *domain)
 130 {
 131   char res[512];
 132   int n;
 133
 134   if((n = srs_forward(srs, orig_sender, domain, res, sizeof(res))) & SRS_RESULT_FAIL)
 135   {
 136     DEBUG(D_any)
 137       debug_printf("srs_forward failed (%s, %s): %s\n", orig_sender, domain, srs_geterrormsg(n));
 138     return DEFER;
 139   }
 140
 141   *result = string_copy(res);
 142   return OK;
 143 }
 144
 145
 146 int eximsrs_reverse(uschar **result, uschar *address)
 147 {
 148   char res[512];
 149   int n;
 150
 151   if((n = srs_reverse(srs, address, res, sizeof(res))) & SRS_RESULT_FAIL)
 152   {
 153     DEBUG(D_any)
 154       debug_printf("srs_reverse failed (%s): %s\n", address, srs_geterrormsg(n));
 155     if(n == SRS_RESULT_NOTSRS || n == SRS_RESULT_BADSRS)
 156       return DECLINE;
 157     if(n == SRS_RESULT_BADHASH || n == SRS_RESULT_BADTIMESTAMP || n == SRS_RESULT_TIMESTAMPEXPIRED)
 158       return FAIL;
 159     return DEFER;
 160   }
 161
 162   *result = string_copy(res);
 163   return OK;
 164 }
 165
 166
 167 int eximsrs_db_set(BOOL reverse, uschar *srs_db)
 168 {
 169   if(reverse)
 170     srs_db_reverse = (srs_db == NULL ? NULL : string_copy(srs_db));
 171   else
 172     srs_db_forward = (srs_db == NULL ? NULL : string_copy(srs_db));
 173
 174   if(srs_set_db_functions(srs, (srs_db_forward ? eximsrs_db_insert : NULL),
 175                                (srs_db_reverse ? eximsrs_db_lookup : NULL)) & SRS_RESULT_FAIL)
 176     return DEFER;
 177
 178   return OK;
 179 }
 180
 181
 182 srs_result eximsrs_db_insert(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 183 {
 184   uschar *res;
 185   uschar buf[64];
 186
 187   if(srs_db_forward == NULL)
 188     return SRS_RESULT_DBERROR;
 189
 190   srs_db_address = string_copyn(data, data_len);
 191   if(srs_generate_unique_id(srs, srs_db_address, buf, 64) & SRS_RESULT_FAIL)
 192     return SRS_RESULT_DBERROR;
 193
 194   srs_db_key = string_copyn(buf, 16);
 195
 196   if((res = expand_string(srs_db_forward)) == NULL)
 197     return SRS_RESULT_DBERROR;
 198
 199   if(result_len < 17)
 200     return SRS_RESULT_DBERROR;
 201
 202   Ustrncpy(result, srs_db_key, result_len);
 203
 204   return SRS_RESULT_OK;
 205 }
 206
 207
 208 srs_result eximsrs_db_lookup(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 209 {
 210   uschar *res;
 211
 212   if(srs_db_reverse == NULL)
 213     return SRS_RESULT_DBERROR;
 214
 215   srs_db_key = string_copyn(data, data_len);
 216   if((res = expand_string(srs_db_reverse)) == NULL)
 217     return SRS_RESULT_DBERROR;
 218
 219   if(Ustrlen(res) >= result_len)
 220     return SRS_RESULT_ADDRESSTOOLONG;
 221
 222   strncpy(result, res, result_len);
 223
 224   return SRS_RESULT_OK;
 225 }
 226
 227
 228 #endif
 229