0f0a05d4dcddd40a2994290052fc0e969d3a9682
[exim.git] / src / src / spf.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Experimental SPF support.
6 Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004 - 2014
7 License: GPL
8 Copyright (c) The Exim Maintainers 2015 - 2018
9 */
10
11 /* Code for calling spf checks via libspf-alt. Called from acl.c. */
12
13 #include "exim.h"
14 #ifdef SUPPORT_SPF
15
16 /* must be kept in numeric order */
17 static spf_result_id spf_result_id_list[] = {
18 /* name value */
19 { US"invalid", 0},
20 { US"neutral", 1 },
21 { US"pass", 2 },
22 { US"fail", 3 },
23 { US"softfail", 4 },
24 { US"none", 5 },
25 { US"err_temp", 6 }, /* Deprecated Apr 2014 */
26 { US"err_perm", 7 }, /* Deprecated Apr 2014 */
27 { US"temperror", 6 }, /* RFC 4408 defined */
28 { US"permerror", 7 } /* RFC 4408 defined */
29 };
30
31 SPF_server_t *spf_server = NULL;
32 SPF_request_t *spf_request = NULL;
33 SPF_response_t *spf_response = NULL;
34 SPF_response_t *spf_response_2mx = NULL;
35
36
37 /* spf_init sets up a context that can be re-used for several
38 messages on the same SMTP connection (that come from the
39 same host with the same HELO string)
40
41 Return: Boolean success */
42
43 BOOL
44 spf_init(uschar *spf_helo_domain, uschar *spf_remote_addr)
45 {
46 spf_server = SPF_server_new(SPF_DNS_CACHE, 0);
47
48 if (!spf_server)
49 {
50 DEBUG(D_receive) debug_printf("spf: SPF_server_new() failed.\n");
51 return FALSE;
52 }
53
54 if (SPF_server_set_rec_dom(spf_server, CS primary_hostname))
55 {
56 DEBUG(D_receive) debug_printf("spf: SPF_server_set_rec_dom(\"%s\") failed.\n",
57 primary_hostname);
58 spf_server = NULL;
59 return FALSE;
60 }
61
62 spf_request = SPF_request_new(spf_server);
63
64 if ( SPF_request_set_ipv4_str(spf_request, CS spf_remote_addr)
65 && SPF_request_set_ipv6_str(spf_request, CS spf_remote_addr)
66 )
67 {
68 DEBUG(D_receive)
69 debug_printf("spf: SPF_request_set_ipv4_str() and "
70 "SPF_request_set_ipv6_str() failed [%s]\n", spf_remote_addr);
71 spf_server = NULL;
72 spf_request = NULL;
73 return FALSE;
74 }
75
76 if (SPF_request_set_helo_dom(spf_request, CS spf_helo_domain))
77 {
78 DEBUG(D_receive) debug_printf("spf: SPF_set_helo_dom(\"%s\") failed.\n",
79 spf_helo_domain);
80 spf_server = NULL;
81 spf_request = NULL;
82 return FALSE;
83 }
84
85 return TRUE;
86 }
87
88
89 /* spf_process adds the envelope sender address to the existing
90 context (if any), retrieves the result, sets up expansion
91 strings and evaluates the condition outcome.
92
93 Return: OK/FAIL */
94
95 int
96 spf_process(const uschar **listptr, uschar *spf_envelope_sender, int action)
97 {
98 int sep = 0;
99 const uschar *list = *listptr;
100 uschar *spf_result_id;
101 int rc = SPF_RESULT_PERMERROR;
102
103 if (!(spf_server && spf_request))
104 /* no global context, assume temp error and skip to evaluation */
105 rc = SPF_RESULT_PERMERROR;
106
107 else if (SPF_request_set_env_from(spf_request, CS spf_envelope_sender))
108 /* Invalid sender address. This should be a real rare occurence */
109 rc = SPF_RESULT_PERMERROR;
110
111 else
112 {
113 /* get SPF result */
114 if (action == SPF_PROCESS_FALLBACK)
115 {
116 SPF_request_query_fallback(spf_request, &spf_response, CS spf_guess);
117 spf_result_guessed = TRUE;
118 }
119 else
120 SPF_request_query_mailfrom(spf_request, &spf_response);
121
122 /* set up expansion items */
123 spf_header_comment = US SPF_response_get_header_comment(spf_response);
124 spf_received = US SPF_response_get_received_spf(spf_response);
125 spf_result = US SPF_strresult(SPF_response_result(spf_response));
126 spf_smtp_comment = US SPF_response_get_smtp_comment(spf_response);
127
128 rc = SPF_response_result(spf_response);
129 }
130
131 /* We got a result. Now see if we should return OK or FAIL for it */
132 DEBUG(D_acl) debug_printf("SPF result is %s (%d)\n", SPF_strresult(rc), rc);
133
134 if (action == SPF_PROCESS_GUESS && (!strcmp (SPF_strresult(rc), "none")))
135 return spf_process(listptr, spf_envelope_sender, SPF_PROCESS_FALLBACK);
136
137 while ((spf_result_id = string_nextinlist(&list, &sep, NULL, 0)))
138 {
139 BOOL negate, result;
140
141 if ((negate = spf_result_id[0] == '!'))
142 spf_result_id++;
143
144 result = Ustrcmp(spf_result_id, spf_result_id_list[rc].name) == 0;
145 if (negate != result) return OK;
146 }
147
148 /* no match */
149 return FAIL;
150 }
151
152
153
154 gstring *
155 authres_spf(gstring * g)
156 {
157 uschar * s;
158 if (!spf_result) return g;
159
160 g = string_append(g, 2, US";\n\tspf=", spf_result);
161 if (spf_result_guessed)
162 g = string_cat(g, US" (best guess record for domain)");
163
164 s = expand_string(US"$sender_address_domain");
165 return s && *s
166 ? string_append(g, 2, US" smtp.mailfrom=", s)
167 : string_cat(g, US" smtp.mailfrom=<>");
168 }
169
170
171 #endif