| 1 | /* $Cambridge: exim/src/src/spf.c,v 1.3 2005/02/17 11:58:26 ph10 Exp $ */ |
| 2 | |
| 3 | /************************************************* |
| 4 | * Exim - an Internet mail transport agent * |
| 5 | *************************************************/ |
| 6 | |
| 7 | /* Experimental SPF support. |
| 8 | Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 |
| 9 | License: GPL */ |
| 10 | |
| 11 | /* Code for calling spf checks via libspf-alt. Called from acl.c. */ |
| 12 | |
| 13 | #include "exim.h" |
| 14 | #ifdef EXPERIMENTAL_SPF |
| 15 | |
| 16 | /* #include "spf.h" */ |
| 17 | |
| 18 | SPF_config_t spfcid = NULL; |
| 19 | SPF_dns_config_t spfdcid_resolv = NULL; |
| 20 | SPF_dns_config_t spfdcid = NULL; |
| 21 | |
| 22 | |
| 23 | /* spf_init sets up a context that can be re-used for several |
| 24 | messages on the same SMTP connection (that come from the |
| 25 | same host with the same HELO string) */ |
| 26 | |
| 27 | int spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr) { |
| 28 | uschar *p; |
| 29 | |
| 30 | /* paranoia */ |
| 31 | spfcid = NULL; |
| 32 | spfdcid_resolv = NULL; |
| 33 | spfdcid = NULL; |
| 34 | |
| 35 | spfcid = SPF_create_config(); |
| 36 | if ( spfcid == NULL ) { |
| 37 | debug_printf("spf: SPF_create_config() failed.\n"); |
| 38 | return 0; |
| 39 | } |
| 40 | |
| 41 | /* set up resolver */ |
| 42 | spfdcid_resolv = SPF_dns_create_config_resolv(NULL, 0); |
| 43 | spfdcid = SPF_dns_create_config_cache(spfdcid_resolv, 8, 0); |
| 44 | |
| 45 | if (spfdcid == NULL) { |
| 46 | debug_printf("spf: SPF_dns_create_config_cache() failed.\n"); |
| 47 | spfcid = NULL; |
| 48 | spfdcid_resolv = NULL; |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | if (SPF_set_ip_str(spfcid, spf_remote_addr)) { |
| 53 | debug_printf("spf: SPF_set_ip_str() failed.\n"); |
| 54 | spfcid = NULL; |
| 55 | spfdcid_resolv = NULL; |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | if (SPF_set_helo_dom(spfcid, spf_helo_domain)) { |
| 60 | debug_printf("spf: SPF_set_helo_dom() failed.\n"); |
| 61 | spfcid = NULL; |
| 62 | spfdcid_resolv = NULL; |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | return 1; |
| 67 | } |
| 68 | |
| 69 | |
| 70 | /* spf_process adds the envelope sender address to the existing |
| 71 | context (if any), retrieves the result, sets up expansion |
| 72 | strings and evaluates the condition outcome. */ |
| 73 | |
| 74 | int spf_process(uschar **listptr, uschar *spf_envelope_sender) { |
| 75 | int sep = 0; |
| 76 | uschar *list = *listptr; |
| 77 | uschar *spf_result_id; |
| 78 | uschar spf_result_id_buffer[128]; |
| 79 | SPF_output_t spf_output; |
| 80 | int rc = SPF_RESULT_ERROR; |
| 81 | |
| 82 | if (!(spfcid && spfdcid)) { |
| 83 | /* no global context, assume temp error and skip to evaluation */ |
| 84 | rc = SPF_RESULT_ERROR; |
| 85 | goto SPF_EVALUATE; |
| 86 | }; |
| 87 | |
| 88 | if (SPF_set_env_from(spfcid, spf_envelope_sender)) { |
| 89 | /* Invalid sender address. This should be a real rare occurence */ |
| 90 | rc = SPF_RESULT_ERROR; |
| 91 | goto SPF_EVALUATE; |
| 92 | } |
| 93 | |
| 94 | /* get SPF result */ |
| 95 | spf_output = SPF_result(spfcid, spfdcid); |
| 96 | |
| 97 | /* set up expansion items */ |
| 98 | spf_header_comment = spf_output.header_comment ? (uschar *)spf_output.header_comment : NULL; |
| 99 | spf_received = spf_output.received_spf ? (uschar *)spf_output.received_spf : NULL; |
| 100 | spf_result = (uschar *)SPF_strresult(spf_output.result); |
| 101 | spf_smtp_comment = spf_output.smtp_comment ? (uschar *)spf_output.smtp_comment : NULL; |
| 102 | |
| 103 | rc = spf_output.result; |
| 104 | |
| 105 | /* We got a result. Now see if we should return OK or FAIL for it */ |
| 106 | SPF_EVALUATE: |
| 107 | debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc); |
| 108 | while ((spf_result_id = string_nextinlist(&list, &sep, |
| 109 | spf_result_id_buffer, |
| 110 | sizeof(spf_result_id_buffer))) != NULL) { |
| 111 | int negate = 0; |
| 112 | int result = 0; |
| 113 | |
| 114 | /* Check for negation */ |
| 115 | if (spf_result_id[0] == '!') { |
| 116 | negate = 1; |
| 117 | spf_result_id++; |
| 118 | }; |
| 119 | |
| 120 | /* Check the result identifier */ |
| 121 | result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name); |
| 122 | if (!negate && result==0) return OK; |
| 123 | if (negate && result!=0) return OK; |
| 124 | }; |
| 125 | |
| 126 | /* no match */ |
| 127 | return FAIL; |
| 128 | } |
| 129 | |
| 130 | #endif |
| 131 | |