d66407a9aef7b39b5e5180aebbd3ef692acf12c3
[exim.git] / src / src / auths / external.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) Jeremy Harris 2019 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* This file provides an Exim authenticator driver for
9 a server to verify a client SSL certificate, using the EXTERNAL
10 method defined in RFC 4422 Appendix A.
11 */
12
13
14 #include "../exim.h"
15 #include "external.h"
16
17 /* Options specific to the external authentication mechanism. */
18
19 optionlist auth_external_options[] = {
20 { "client_send", opt_stringptr, OPT_OFF(auth_external_options_block, client_send) },
21 { "server_param2", opt_stringptr, OPT_OFF(auth_external_options_block, server_param2) },
22 { "server_param3", opt_stringptr, OPT_OFF(auth_external_options_block, server_param3) },
23 };
24
25 /* Size of the options list. An extern variable has to be used so that its
26 address can appear in the tables drtables.c. */
27
28 int auth_external_options_count = nelem(auth_external_options);
29
30 /* Default private options block for the authentication method. */
31
32 auth_external_options_block auth_external_option_defaults = {
33 .server_param2 = NULL,
34 .server_param3 = NULL,
35
36 .client_send = NULL,
37 };
38
39
40 #ifdef MACRO_PREDEF
41
42 /* Dummy values */
43 void auth_external_init(auth_instance *ablock) {}
44 int auth_external_server(auth_instance *ablock, uschar *data) {return 0;}
45 int auth_external_client(auth_instance *ablock, void * sx,
46 int timeout, uschar *buffer, int buffsize) {return 0;}
47
48 #else /*!MACRO_PREDEF*/
49
50
51
52
53 /*************************************************
54 * Initialization entry point *
55 *************************************************/
56
57 /* Called for each instance, after its options have been read, to
58 enable consistency checks to be done, or anything else that needs
59 to be set up. */
60
61 void
62 auth_external_init(auth_instance *ablock)
63 {
64 auth_external_options_block * ob = (auth_external_options_block *)ablock->options_block;
65 if (!ablock->public_name) ablock->public_name = ablock->name;
66 if (ablock->server_condition) ablock->server = TRUE;
67 if (ob->client_send) ablock->client = TRUE;
68 }
69
70
71
72 /*************************************************
73 * Server entry point *
74 *************************************************/
75
76 /* For interface, see auths/README */
77
78 int
79 auth_external_server(auth_instance * ablock, uschar * data)
80 {
81 auth_external_options_block * ob = (auth_external_options_block *)ablock->options_block;
82 int rc;
83
84 /* If data was supplied on the AUTH command, decode it, and split it up into
85 multiple items at binary zeros. The strings are put into $auth1, $auth2, etc,
86 up to a maximum. To retain backwards compatibility, they are also put int $1,
87 $2, etc. If the data consists of the string "=" it indicates a single, empty
88 string. */
89
90 if (*data)
91 if ((rc = auth_read_input(data)) != OK)
92 return rc;
93
94 /* Now go through the list of prompt strings. Skip over any whose data has
95 already been provided as part of the AUTH command. For the rest, send them
96 out as prompts, and get a data item back. If the data item is "*", abandon the
97 authentication attempt. Otherwise, split it into items as above. */
98
99 if (expand_nmax == 0) /* skip if rxd data */
100 if ((rc = auth_prompt(CUS"")) != OK)
101 return rc;
102
103 if (ob->server_param2)
104 {
105 uschar * s = expand_string(ob->server_param2);
106 auth_vars[expand_nmax] = s;
107 expand_nstring[++expand_nmax] = s;
108 expand_nlength[expand_nmax] = Ustrlen(s);
109 if (ob->server_param3)
110 {
111 s = expand_string(ob->server_param3);
112 auth_vars[expand_nmax] = s;
113 expand_nstring[++expand_nmax] = s;
114 expand_nlength[expand_nmax] = Ustrlen(s);
115 }
116 }
117
118 return auth_check_serv_cond(ablock);
119 }
120
121
122
123 /*************************************************
124 * Client entry point *
125 *************************************************/
126
127 /* For interface, see auths/README */
128
129 int
130 auth_external_client(
131 auth_instance *ablock, /* authenticator block */
132 void * sx, /* smtp connextion */
133 int timeout, /* command timeout */
134 uschar *buffer, /* buffer for reading response */
135 int buffsize) /* size of buffer */
136 {
137 auth_external_options_block *ob =
138 (auth_external_options_block *)(ablock->options_block);
139 const uschar * text = ob->client_send;
140 int rc;
141
142 /* We output an AUTH command with one expanded argument, the client_send option */
143
144 if ((rc = auth_client_item(sx, ablock, &text, AUTH_ITEM_FIRST | AUTH_ITEM_LAST,
145 timeout, buffer, buffsize)) != OK)
146 return rc == DEFER ? FAIL : rc;
147
148 if (text) auth_vars[0] = string_copy(text);
149 return OK;
150 }
151
152
153
154 #endif /*!MACRO_PREDEF*/
155 /* End of external.c */