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Diffstat (limited to '')
| -rw-r--r-- | src/srs.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/srs.c b/src/srs.c new file mode 100644 index 0000000..1ff391f --- /dev/null +++ b/src/srs.c @@ -0,0 +1,230 @@ +/************************************************* +* 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 + |