-/*************************************************
-* Exim - an Internet mail transport agent *
-*************************************************/
-
-/* SPF support.
- Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014
- License: GPL
- Copyright (c) The Exim Maintainers 2015 - 2019
-*/
-
-/* Code for calling spf checks via libspf-alt. Called from acl.c. */
-
-#include "exim.h"
-#ifdef SUPPORT_SPF
-
-/* must be kept in numeric order */
-static spf_result_id spf_result_id_list[] = {
- /* name value */
- { US"invalid", 0},
- { US"neutral", 1 },
- { US"pass", 2 },
- { US"fail", 3 },
- { US"softfail", 4 },
- { US"none", 5 },
- { US"temperror", 6 }, /* RFC 4408 defined */
- { US"permerror", 7 } /* RFC 4408 defined */
-};
-
-SPF_server_t *spf_server = NULL;
-SPF_request_t *spf_request = NULL;
-SPF_response_t *spf_response = NULL;
-SPF_response_t *spf_response_2mx = NULL;
-
-SPF_dns_rr_t * spf_nxdomain = NULL;
-
-
-void
-spf_lib_version_report(FILE * fp)
-{
-int maj, min, patch;
-SPF_get_lib_version(&maj, &min, &patch);
-fprintf(fp, "Library version: spf2: Compile: %d.%d.%d\n",
- SPF_LIB_VERSION_MAJOR, SPF_LIB_VERSION_MINOR, SPF_LIB_VERSION_PATCH);
-fprintf(fp, " Runtime: %d.%d.%d\n",
- maj, min, patch);
-}
-
-
-
-static SPF_dns_rr_t *
-SPF_dns_exim_lookup(SPF_dns_server_t *spf_dns_server,
- const char *domain, ns_type rr_type, int should_cache)
-{
-dns_answer * dnsa = store_get_dns_answer();
-dns_scan dnss;
-SPF_dns_rr_t * spfrr;
-unsigned found = 0;
-
-SPF_dns_rr_t srr = {
- .domain = CS domain, /* query information */
- .domain_buf_len = 0,
- .rr_type = rr_type,
-
- .rr_buf_len = 0, /* answer information */
- .rr_buf_num = 0, /* no free of s */
- .utc_ttl = 0,
-
- .hook = NULL, /* misc information */
- .source = spf_dns_server
-};
-int dns_rc;
-
-DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", domain);
-
-switch (dns_rc = dns_lookup(dnsa, US domain, rr_type, NULL))
- {
- case DNS_SUCCEED: srr.herrno = NETDB_SUCCESS; break;
- case DNS_AGAIN: srr.herrno = TRY_AGAIN; break;
- case DNS_NOMATCH: srr.herrno = HOST_NOT_FOUND; break;
- case DNS_NODATA: srr.herrno = NO_DATA; break;
- case DNS_FAIL:
- default: srr.herrno = NO_RECOVERY; break;
- }
-
-for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
- rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
- if (rr->type == rr_type) found++;
-
-if (found == 0)
- {
- SPF_dns_rr_dup(&spfrr, &srr);
- return spfrr;
- }
-
-srr.rr = store_malloc(sizeof(SPF_dns_rr_data_t) * found);
-
-found = 0;
-for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
- rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
- if (rr->type == rr_type)
- {
- const uschar * s = rr->data;
-
- srr.ttl = rr->ttl;
- switch(rr_type)
- {
- case T_MX:
- s += 2; /* skip the MX precedence field */
- case T_PTR:
- {
- uschar * buf = store_malloc(256);
- (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, s,
- (DN_EXPAND_ARG4_TYPE)buf, 256);
- s = buf;
- break;
- }
-
- case T_TXT:
- {
- gstring * g = NULL;
- uschar chunk_len;
-
- if (strncmpic(rr->data+1, US SPF_VER_STR, 6) != 0)
- {
- HDEBUG(D_host_lookup) debug_printf("not an spf record\n");
- continue;
- }
-
- for (int off = 0; off < rr->size; off += chunk_len)
- {
- if (!(chunk_len = s[off++])) break;
- g = string_catn(g, s+off, chunk_len);
- }
- if (!g)
- continue;
- gstring_release_unused(g);
- s = string_copy_malloc(string_from_gstring(g));
- break;
- }
-
- case T_A:
- case T_AAAA:
- default:
- {
- uschar * buf = store_malloc(dnsa->answerlen + 1);
- s = memcpy(buf, s, dnsa->answerlen + 1);
- break;
- }
- }
- DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", s);
- srr.rr[found++] = (void *) s;
- }
-
-srr.num_rr = found;
-/* spfrr->rr must have been malloc()d for this */
-SPF_dns_rr_dup(&spfrr, &srr);
-return spfrr;
-}
-
-
-
-SPF_dns_server_t *
-SPF_dns_exim_new(int debug)
-{
-SPF_dns_server_t * spf_dns_server = store_malloc(sizeof(SPF_dns_server_t));
-
-DEBUG(D_receive) debug_printf("SPF_dns_exim_new\n");
-
-memset(spf_dns_server, 0, sizeof(SPF_dns_server_t));
-spf_dns_server->destroy = NULL;
-spf_dns_server->lookup = SPF_dns_exim_lookup;
-spf_dns_server->get_spf = NULL;
-spf_dns_server->get_exp = NULL;
-spf_dns_server->add_cache = NULL;
-spf_dns_server->layer_below = NULL;
-spf_dns_server->name = "exim";
-spf_dns_server->debug = debug;
-
-/* XXX This might have to return NO_DATA sometimes. */
-
-spf_nxdomain = SPF_dns_rr_new_init(spf_dns_server,
- "", ns_t_any, 24 * 60 * 60, HOST_NOT_FOUND);
-if (!spf_nxdomain)
- {
- free(spf_dns_server);
- return NULL;
- }
-
-return spf_dns_server;
-}
-
-
-
-
-/* Construct the SPF library stack.
- Return: Boolean success.
-*/
-
-BOOL
-spf_init(void)
-{
-SPF_dns_server_t * dc;
-int debug = 0;
-
-DEBUG(D_receive) debug = 1;
-
-/* We insert our own DNS access layer rather than letting the spf library
-do it, so that our dns access path is used for debug tracing and for the
-testsuite. */
-
-if (!(dc = SPF_dns_exim_new(debug)))
- {
- DEBUG(D_receive) debug_printf("spf: SPF_dns_exim_new() failed\n");
- return FALSE;
- }
-if (!(dc = SPF_dns_cache_new(dc, NULL, debug, 8)))
- {
- DEBUG(D_receive) debug_printf("spf: SPF_dns_cache_new() failed\n");
- return FALSE;
- }
-if (!(spf_server = SPF_server_new_dns(dc, debug)))
- {
- DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n");
- return FALSE;
- }
- /* Quick hack to override the outdated explanation URL.
- See https://www.mail-archive.com/mailop@mailop.org/msg08019.html */
- SPF_server_set_explanation(spf_server, "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}", &spf_response);
- if (SPF_response_errcode(spf_response) != SPF_E_SUCCESS)
- log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", SPF_strerror(SPF_response_errcode(spf_response)));
-
-return TRUE;
-}
-
-
-/* Set up a context that can be re-used for several
- messages on the same SMTP connection (that come from the
- same host with the same HELO string).
-
-Return: Boolean success
-*/
-
-BOOL
-spf_conn_init(uschar * spf_helo_domain, uschar * spf_remote_addr)
-{
-DEBUG(D_receive)
- debug_printf("spf_conn_init: %s %s\n", spf_helo_domain, spf_remote_addr);
-
-if (!spf_server && !spf_init()) return FALSE;
-
-if (SPF_server_set_rec_dom(spf_server, CS primary_hostname))
- {
- DEBUG(D_receive) debug_printf("spf: SPF_server_set_rec_dom(\"%s\") failed.\n",
- primary_hostname);
- spf_server = NULL;
- return FALSE;
- }
-
-spf_request = SPF_request_new(spf_server);
-
-if ( SPF_request_set_ipv4_str(spf_request, CS spf_remote_addr)
- && SPF_request_set_ipv6_str(spf_request, CS spf_remote_addr)
- )
- {
- DEBUG(D_receive)
- debug_printf("spf: SPF_request_set_ipv4_str() and "
- "SPF_request_set_ipv6_str() failed [%s]\n", spf_remote_addr);
- spf_server = NULL;
- spf_request = NULL;
- return FALSE;
- }
-
-if (SPF_request_set_helo_dom(spf_request, CS spf_helo_domain))
- {
- DEBUG(D_receive) debug_printf("spf: SPF_set_helo_dom(\"%s\") failed.\n",
- spf_helo_domain);
- spf_server = NULL;
- spf_request = NULL;
- return FALSE;
- }
-
-return TRUE;
-}
-
-
-/* spf_process adds the envelope sender address to the existing
- context (if any), retrieves the result, sets up expansion
- strings and evaluates the condition outcome.
-
-Return: OK/FAIL */
-
-int
-spf_process(const uschar **listptr, uschar *spf_envelope_sender, int action)
-{
-int sep = 0;
-const uschar *list = *listptr;
-uschar *spf_result_id;
-int rc = SPF_RESULT_PERMERROR;
-
-DEBUG(D_receive) debug_printf("spf_process\n");
-
-if (!(spf_server && spf_request))
- /* no global context, assume temp error and skip to evaluation */
- rc = SPF_RESULT_PERMERROR;
-
-else if (SPF_request_set_env_from(spf_request, CS spf_envelope_sender))
- /* Invalid sender address. This should be a real rare occurrence */
- rc = SPF_RESULT_PERMERROR;
-
-else
- {
- /* get SPF result */
- if (action == SPF_PROCESS_FALLBACK)
- {
- SPF_request_query_fallback(spf_request, &spf_response, CS spf_guess);
- spf_result_guessed = TRUE;
- }
- else
- SPF_request_query_mailfrom(spf_request, &spf_response);
-
- /* set up expansion items */
- spf_header_comment = US SPF_response_get_header_comment(spf_response);
- spf_received = US SPF_response_get_received_spf(spf_response);
- spf_result = US SPF_strresult(SPF_response_result(spf_response));
- spf_smtp_comment = US SPF_response_get_smtp_comment(spf_response);
-
- rc = SPF_response_result(spf_response);
- }
-
-/* We got a result. Now see if we should return OK or FAIL for it */
-DEBUG(D_acl) debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc);
-
-if (action == SPF_PROCESS_GUESS && (!strcmp (SPF_strresult(rc), "none")))
- return spf_process(listptr, spf_envelope_sender, SPF_PROCESS_FALLBACK);
-
-while ((spf_result_id = string_nextinlist(&list, &sep, NULL, 0)))
- {
- BOOL negate, result;
-
- if ((negate = spf_result_id[0] == '!'))
- spf_result_id++;
-
- result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name) == 0;
- if (negate != result) return OK;
- }
-
-/* no match */
-return FAIL;
-}
-
-
-
-gstring *
-authres_spf(gstring * g)
-{
-uschar * s;
-if (!spf_result) return g;
-
-g = string_append(g, 2, US";\n\tspf=", spf_result);
-if (spf_result_guessed)
- g = string_cat(g, US" (best guess record for domain)");
-
-s = expand_string(US"$sender_address_domain");
-return s && *s
- ? string_append(g, 2, US" smtp.mailfrom=", s)
- : string_cat(g, US" smtp.mailfrom=<>");
-}
-
-
-#endif
git://git.exim.org / exim.git / blobdiff