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-rw-r--r--src/srs.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/src/srs.c b/src/srs.c
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+++ b/src/srs.c
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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))))
+ maxage = atoi(sbuf);
+
+ if ((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))))
+ hashlen = atoi(sbuf);
+
+ if ((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))))
+ usetimestamp = atoi(sbuf);
+
+ if ((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))))
+ 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)))
+ {
+ 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)))
+ {
+ 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)))
+ 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) 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
+