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/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
/* SRS - Sender rewriting scheme support
(C)2004 Miles Wilton <miles@mirtol.com>
Copyright (c) The Exim Maintainers 2016
SRS Support Version: 1.0a
License: GPL */
#include "exim.h"
#ifdef EXPERIMENTAL_SRS
#include <srs_alt.h>
#include "srs.h"
srs_t *srs = NULL;
uschar *srs_db_forward = NULL;
uschar *srs_db_reverse = NULL;
/* srs_init just initialises libsrs and creates (if necessary)
an srs object to use for all srs calls in this instance */
int eximsrs_init()
{
const uschar *list = srs_config;
uschar secret_buf[SRS_MAX_SECRET_LENGTH];
uschar *secret = NULL;
uschar sbuf[4];
uschar *sbufp;
/* Check if this instance of Exim has not initialized SRS */
if(srs == NULL)
{
int co = 0;
int hashlen, maxage;
BOOL usetimestamp, usehash;
/* Copy config vars */
hashlen = srs_hashlength;
maxage = srs_maxage;
usetimestamp = srs_usetimestamp;
usehash = srs_usehash;
/* Pass srs_config var (overrides new config vars) */
co = 0;
if(srs_config != NULL)
{
secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH);
if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
maxage = atoi(sbuf);
if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
hashlen = atoi(sbuf);
if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
usetimestamp = atoi(sbuf);
if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
usehash = atoi(sbuf);
}
if(srs_hashmin == -1)
srs_hashmin = hashlen;
/* First secret specified in secrets? */
co = 0;
list = srs_secrets;
if(secret == NULL || *secret == '\0')
{
if((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) == NULL)
{
log_write(0, LOG_MAIN | LOG_PANIC,
"SRS Configuration Error: No secret specified");
return DEFER;
}
}
/* Check config */
if(maxage < 0 || maxage > 365)
{
log_write(0, LOG_MAIN | LOG_PANIC,
"SRS Configuration Error: Invalid maximum timestamp age");
return DEFER;
}
if(hashlen < 1 || hashlen > 20 || srs_hashmin < 1 || srs_hashmin > 20)
{
log_write(0, LOG_MAIN | LOG_PANIC,
"SRS Configuration Error: Invalid hash length");
return DEFER;
}
if((srs = srs_open(secret, Ustrlen(secret), maxage, hashlen, srs_hashmin)) == NULL)
{
log_write(0, LOG_MAIN | LOG_PANIC,
"Failed to allocate SRS memory");
return DEFER;
}
srs_set_option(srs, SRS_OPTION_USETIMESTAMP, usetimestamp);
srs_set_option(srs, SRS_OPTION_USEHASH, usehash);
/* Extra secrets? */
while((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) != NULL)
srs_add_secret(srs, secret, (Ustrlen(secret) > SRS_MAX_SECRET_LENGTH) ? SRS_MAX_SECRET_LENGTH : Ustrlen(secret));
DEBUG(D_any)
debug_printf("SRS initialized\n");
}
return OK;
}
int eximsrs_done()
{
if(srs != NULL)
srs_close(srs);
srs = NULL;
return OK;
}
int eximsrs_forward(uschar **result, uschar *orig_sender, uschar *domain)
{
char res[512];
int n;
if((n = srs_forward(srs, orig_sender, domain, res, sizeof(res))) & SRS_RESULT_FAIL)
{
DEBUG(D_any)
debug_printf("srs_forward failed (%s, %s): %s\n", orig_sender, domain, srs_geterrormsg(n));
return DEFER;
}
*result = string_copy(res);
return OK;
}
int eximsrs_reverse(uschar **result, uschar *address)
{
char res[512];
int n;
if((n = srs_reverse(srs, address, res, sizeof(res))) & SRS_RESULT_FAIL)
{
DEBUG(D_any)
debug_printf("srs_reverse failed (%s): %s\n", address, srs_geterrormsg(n));
if(n == SRS_RESULT_NOTSRS || n == SRS_RESULT_BADSRS)
return DECLINE;
if(n == SRS_RESULT_BADHASH || n == SRS_RESULT_BADTIMESTAMP || n == SRS_RESULT_TIMESTAMPEXPIRED)
return FAIL;
return DEFER;
}
*result = string_copy(res);
return OK;
}
int eximsrs_db_set(BOOL reverse, uschar *srs_db)
{
if(reverse)
srs_db_reverse = (srs_db == NULL ? NULL : string_copy(srs_db));
else
srs_db_forward = (srs_db == NULL ? NULL : string_copy(srs_db));
if(srs_set_db_functions(srs, (srs_db_forward ? eximsrs_db_insert : NULL),
(srs_db_reverse ? eximsrs_db_lookup : NULL)) & SRS_RESULT_FAIL)
return DEFER;
return OK;
}
srs_result eximsrs_db_insert(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
{
uschar *res;
uschar buf[64];
if(srs_db_forward == NULL)
return SRS_RESULT_DBERROR;
srs_db_address = string_copyn(data, data_len);
if(srs_generate_unique_id(srs, srs_db_address, buf, 64) & SRS_RESULT_FAIL)
return SRS_RESULT_DBERROR;
srs_db_key = string_copyn(buf, 16);
if((res = expand_string(srs_db_forward)) == NULL)
return SRS_RESULT_DBERROR;
if(result_len < 17)
return SRS_RESULT_DBERROR;
Ustrncpy(result, srs_db_key, result_len);
return SRS_RESULT_OK;
}
srs_result eximsrs_db_lookup(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
{
uschar *res;
if(srs_db_reverse == NULL)
return SRS_RESULT_DBERROR;
srs_db_key = string_copyn(data, data_len);
if((res = expand_string(srs_db_reverse)) == NULL)
return SRS_RESULT_DBERROR;
if(Ustrlen(res) >= result_len)
return SRS_RESULT_ADDRESSTOOLONG;
strncpy(result, res, result_len);
return SRS_RESULT_OK;
}
#endif
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