X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/8743d3acaaa2262007aa2862ffecd6b19125e38d..2ead369f8435918f3f15408b9394e580bcaf0910:/src/src/spf.c diff --git a/src/src/spf.c b/src/src/spf.c index 8b7bf4bc9..e3df789fb 100644 --- a/src/src/spf.c +++ b/src/src/spf.c @@ -5,7 +5,7 @@ /* SPF support. Copyright (c) Tom Kistner 2004 - 2014 License: GPL - Copyright (c) The Exim Maintainers 2015 - 2019 + Copyright (c) The Exim Maintainers 2015 - 2021 */ /* Code for calling spf checks via libspf-alt. Called from acl.c. */ @@ -34,65 +34,148 @@ SPF_response_t *spf_response_2mx = NULL; SPF_dns_rr_t * spf_nxdomain = NULL; +gstring * +spf_lib_version_report(gstring * g) +{ +int maj, min, patch; + +SPF_get_lib_version(&maj, &min, &patch); +g = string_fmt_append(g, "Library version: spf2: Compile: %d.%d.%d\n", + SPF_LIB_VERSION_MAJOR, SPF_LIB_VERSION_MINOR, SPF_LIB_VERSION_PATCH); +g = string_fmt_append(g, " Runtime: %d.%d.%d\n", + maj, min, patch); +return g; +} + + 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) + 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); + +/* Shortcircuit SPF RR lookups by returning NO_DATA. They were obsoleted by +RFC 6686/7208 years ago. see bug #1294 */ + +if (rr_type == T_SPF) + { + HDEBUG(D_host_lookup) debug_printf("faking NO_DATA for SPF RR(99) lookup\n"); + srr.herrno = NO_DATA; + SPF_dns_rr_dup(&spfrr, &srr); + store_free_dns_answer(dnsa); + return spfrr; + } + +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); + store_free_dns_answer(dnsa); + return spfrr; + } + +srr.rr = store_malloc(sizeof(SPF_dns_rr_data_t) * found); -DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup\n"); +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; -if (dns_lookup(dnsa, US domain, rr_type, NULL) == DNS_SUCCEED) - 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 - && Ustrncmp(rr->data+1, "v=spf1", 6) == 0) + srr.ttl = rr->ttl; + switch(rr_type) { - gstring * g = NULL; - uschar chunk_len; - uschar * s; - SPF_dns_rr_t srr = { - .domain = CS rr->name, /* query information */ - .domain_buf_len = DNS_MAXNAME, - .rr_type = rr->type, - - .num_rr = 1, /* answer information */ - .rr = NULL, - .rr_buf_len = 0, - .rr_buf_num = 0, - .ttl = rr->ttl, - .utc_ttl = 0, - .herrno = NETDB_SUCCESS, - - .hook = NULL, /* misc information */ - .source = spf_dns_server - }; - - for (int off = 0; off < rr->size; off += chunk_len) + 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: { - chunk_len = (rr->data)[off++]; - g = string_catn(g, US ((rr->data)+off), chunk_len); + 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: %.*s\n", + (int) s[0], s+1); + 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)); + DEBUG(D_receive) debug_printf("SPF_dns_exim_lookup '%s'\n", s); + break; } - if (!g) + + case T_A: + case T_AAAA: + default: { - HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an " - "empty name: treated as non-existent host name\n"); - continue; + uschar * buf = store_malloc(dnsa->answerlen + 1); + s = memcpy(buf, s, dnsa->answerlen + 1); + break; } - gstring_release_unused(g); - s = string_copy_malloc(string_from_gstring(g)); - srr.rr = (void *) &s; + } + srr.rr[found++] = (void *) s; + } - /* spfrr->rr must have been malloc()d for this */ - SPF_dns_rr_dup(&spfrr, &srr); +/* Did we filter out all TXT RRs? Return NO_DATA instead of SUCCESS with +empty ANSWER section. */ - return spfrr; - } +if (!(srr.num_rr = found)) + srr.herrno = NO_DATA; -SPF_dns_rr_dup(&spfrr, spf_nxdomain); +/* spfrr->rr must have been malloc()d for this */ +SPF_dns_rr_dup(&spfrr, &srr); +store_free_dns_answer(dnsa); return spfrr; } @@ -101,14 +184,11 @@ return spfrr; SPF_dns_server_t * SPF_dns_exim_new(int debug) { -SPF_dns_server_t *spf_dns_server; +SPF_dns_server_t * spf_dns_server = store_malloc(sizeof(SPF_dns_server_t)); DEBUG(D_receive) debug_printf("SPF_dns_exim_new\n"); -if (!(spf_dns_server = malloc(sizeof(SPF_dns_server_t)))) - return NULL; 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; @@ -133,25 +213,19 @@ return spf_dns_server; -/* spf_init sets 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). -XXX the spf_server layer could usefully be separately init'd -given that it sets up a dns cache. -Return: Boolean success */ +/* Construct the SPF library stack. + Return: Boolean success. +*/ BOOL -spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) +spf_init(void) { -int debug = 0; SPF_dns_server_t * dc; +int debug = 0; +const uschar *s; -DEBUG(D_receive) - { - debug_printf("spf_init: %s %s\n", spf_helo_domain, spf_remote_addr); - debug = 1; - } +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 @@ -172,6 +246,35 @@ if (!(spf_server = SPF_server_new_dns(dc, debug))) DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n"); return FALSE; } + /* Override the outdated explanation URL. + See https://www.mail-archive.com/mailop@mailop.org/msg08019.html + Used to work as "Please%_see%_http://www.open-spf.org/Why?id=%{S}&ip=%{C}&receiver=%{R}", + but is broken now (May 18th, 2020) */ +if (!(s = expand_string(spf_smtp_comment_template))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "expansion of spf_smtp_comment_template failed"); + +SPF_server_set_explanation(spf_server, CCS s, &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)) { @@ -208,6 +311,22 @@ return TRUE; } +void +spf_response_debug(SPF_response_t * spf_response) +{ +if (SPF_response_messages(spf_response) == 0) + debug_printf(" (no errors)\n"); +else for (int i = 0; i < SPF_response_messages(spf_response); i++) + { + SPF_error_t * err = SPF_response_message(spf_response, i); + debug_printf( "%s_msg = (%d) %s\n", + (SPF_error_errorp(err) ? "warn" : "err"), + SPF_error_code(err), + SPF_error_message(err)); + } +} + + /* 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. @@ -250,6 +369,8 @@ else spf_smtp_comment = US SPF_response_get_smtp_comment(spf_response); rc = SPF_response_result(spf_response); + + DEBUG(D_acl) spf_response_debug(spf_response); } /* We got a result. Now see if we should return OK or FAIL for it */ @@ -286,8 +407,12 @@ if (spf_result_guessed) g = string_cat(g, US" (best guess record for domain)"); s = expand_string(US"$sender_address_domain"); +if (s && *s) + return string_append(g, 2, US" smtp.mailfrom=", s); + +s = sender_helo_name; return s && *s - ? string_append(g, 2, US" smtp.mailfrom=", s) + ? string_append(g, 2, US" smtp.helo=", s) : string_cat(g, US" smtp.mailfrom=<>"); }