xref: /openbsd/usr.bin/ssh/auth-bsdauth.c (revision 09467b48)
1 /* $OpenBSD: auth-bsdauth.c,v 1.15 2018/07/09 21:35:50 markus Exp $ */
2 /*
3  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/types.h>
27 #include <stdarg.h>
28 #include <stdio.h>
29 
30 #include "xmalloc.h"
31 #include "sshkey.h"
32 #include "sshbuf.h"
33 #include "hostfile.h"
34 #include "auth.h"
35 #include "log.h"
36 #ifdef GSSAPI
37 #include "ssh-gss.h"
38 #endif
39 #include "monitor_wrap.h"
40 
41 static void *
42 bsdauth_init_ctx(Authctxt *authctxt)
43 {
44 	return authctxt;
45 }
46 
47 int
48 bsdauth_query(void *ctx, char **name, char **infotxt,
49    u_int *numprompts, char ***prompts, u_int **echo_on)
50 {
51 	Authctxt *authctxt = ctx;
52 	char *challenge = NULL;
53 
54 	*infotxt = NULL;
55 	*numprompts = 0;
56 	*prompts = NULL;
57 	*echo_on = NULL;
58 
59 	if (authctxt->as != NULL) {
60 		debug2("bsdauth_query: try reuse session");
61 		challenge = auth_getitem(authctxt->as, AUTHV_CHALLENGE);
62 		if (challenge == NULL) {
63 			auth_close(authctxt->as);
64 			authctxt->as = NULL;
65 		}
66 	}
67 
68 	if (challenge == NULL) {
69 		debug2("bsdauth_query: new bsd auth session");
70 		debug3("bsdauth_query: style %s",
71 		    authctxt->style ? authctxt->style : "<default>");
72 		authctxt->as = auth_userchallenge(authctxt->user,
73 		    authctxt->style, "auth-ssh", &challenge);
74 		if (authctxt->as == NULL)
75 			challenge = NULL;
76 		debug2("bsdauth_query: <%s>", challenge ? challenge : "empty");
77 	}
78 
79 	if (challenge == NULL)
80 		return -1;
81 
82 	*name = xstrdup("");
83 	*infotxt = xstrdup("");
84 	*numprompts = 1;
85 	*prompts = xcalloc(*numprompts, sizeof(char *));
86 	*echo_on = xcalloc(*numprompts, sizeof(u_int));
87 	(*prompts)[0] = xstrdup(challenge);
88 
89 	return 0;
90 }
91 
92 int
93 bsdauth_respond(void *ctx, u_int numresponses, char **responses)
94 {
95 	Authctxt *authctxt = ctx;
96 	int authok;
97 
98 	if (!authctxt->valid)
99 		return -1;
100 
101 	if (authctxt->as == NULL)
102 		error("bsdauth_respond: no bsd auth session");
103 
104 	if (numresponses != 1)
105 		return -1;
106 
107 	authok = auth_userresponse(authctxt->as, responses[0], 0);
108 	authctxt->as = NULL;
109 	debug3("bsdauth_respond: <%s> = <%d>", responses[0], authok);
110 
111 	return (authok == 0) ? -1 : 0;
112 }
113 
114 static void
115 bsdauth_free_ctx(void *ctx)
116 {
117 	Authctxt *authctxt = ctx;
118 
119 	if (authctxt && authctxt->as) {
120 		auth_close(authctxt->as);
121 		authctxt->as = NULL;
122 	}
123 }
124 
125 KbdintDevice bsdauth_device = {
126 	"bsdauth",
127 	bsdauth_init_ctx,
128 	bsdauth_query,
129 	bsdauth_respond,
130 	bsdauth_free_ctx
131 };
132 
133 KbdintDevice mm_bsdauth_device = {
134 	"bsdauth",
135 	bsdauth_init_ctx,
136 	mm_bsdauth_query,
137 	mm_bsdauth_respond,
138 	bsdauth_free_ctx
139 };
140