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Diffstat (limited to 'src/spf.c')
| -rw-r--r-- | src/spf.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/src/spf.c b/src/spf.c new file mode 100644 index 0000000..0b00a5c --- /dev/null +++ b/src/spf.c @@ -0,0 +1,169 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Experimental SPF support. + Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014 + License: GPL + Copyright (c) The Exim Maintainers 2015 - 2018 +*/ + +/* 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_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) + +Return: Boolean success */ + +BOOL +spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) +{ +spf_server = SPF_server_new(SPF_DNS_CACHE, 0); + +if (!spf_server) + { + DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n"); + 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; + +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 |