summaryrefslogtreecommitdiff
path: root/auth2-pam.c
blob: 99aedeaebbebe61bd017ba3f591ce165b29e0752 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
#include "includes.h"
RCSID("$Id: auth2-pam.c,v 1.13 2002/06/26 13:58:00 djm Exp $");

#ifdef USE_PAM
#include <security/pam_appl.h>

#include "ssh.h"
#include "ssh2.h"
#include "auth.h"
#include "auth-pam.h"
#include "packet.h"
#include "xmalloc.h"
#include "dispatch.h"
#include "log.h"

static int do_pam_conversation_kbd_int(int num_msg, 
    const struct pam_message **msg, struct pam_response **resp, 
    void *appdata_ptr);
void input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt);

struct {
	int finished, num_received, num_expected;
	int *prompts;
	struct pam_response *responses;
} context_pam2 = {0, 0, 0, NULL};

static struct pam_conv conv2 = {
	do_pam_conversation_kbd_int,
	NULL,
};

int
auth2_pam(Authctxt *authctxt)
{
	int retval = -1;

	if (authctxt->user == NULL)
		fatal("auth2_pam: internal error: no user");

	conv2.appdata_ptr = authctxt;
	do_pam_set_conv(&conv2);

	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
	    &input_userauth_info_response_pam);
	retval = (do_pam_authenticate(0) == PAM_SUCCESS);
	dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);

	return retval;
}

static int
do_pam_conversation_kbd_int(int num_msg, const struct pam_message **msg,
    struct pam_response **resp, void *appdata_ptr)
{
	int i, j, done;
	char *text;

	context_pam2.finished = 0;
	context_pam2.num_received = 0;
	context_pam2.num_expected = 0;
	context_pam2.prompts = xmalloc(sizeof(int) * num_msg);
	context_pam2.responses = xmalloc(sizeof(struct pam_response) * num_msg);
	memset(context_pam2.responses, 0, sizeof(struct pam_response) * num_msg);

	text = NULL;
	for (i = 0, context_pam2.num_expected = 0; i < num_msg; i++) {
		int style = PAM_MSG_MEMBER(msg, i, msg_style);
		switch (style) {
		case PAM_PROMPT_ECHO_ON:
		case PAM_PROMPT_ECHO_OFF:
			context_pam2.num_expected++;
			break;
		case PAM_TEXT_INFO:
		case PAM_ERROR_MSG:
		default:
			/* Capture all these messages to be sent at once */
			message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
			break;
		}
	}

	if (context_pam2.num_expected == 0)
		return PAM_SUCCESS;

	packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
	packet_put_cstring("");	/* Name */
	packet_put_cstring("");	/* Instructions */
	packet_put_cstring("");	/* Language */
	packet_put_int(context_pam2.num_expected);
	
	for (i = 0, j = 0; i < num_msg; i++) {
		int style = PAM_MSG_MEMBER(msg, i, msg_style);
		
		/* Skip messages which don't need a reply */
		if (style != PAM_PROMPT_ECHO_ON && style != PAM_PROMPT_ECHO_OFF)
			continue;
		
		context_pam2.prompts[j++] = i;
		if (text) {
			message_cat(&text, PAM_MSG_MEMBER(msg, i, msg));
			packet_put_cstring(text);
			text = NULL;
		} else
			packet_put_cstring(PAM_MSG_MEMBER(msg, i, msg));
		packet_put_char(style == PAM_PROMPT_ECHO_ON);
	}
	packet_send();
	packet_write_wait();

	/*
	 * Grabbing control of execution and spinning until we get what
	 * we want is probably rude, but it seems to work properly, and
	 * the client *should* be in lock-step with us, so the loop should
	 * only be traversed once.
	 */
	while(context_pam2.finished == 0) {
		done = 1;
		dispatch_run(DISPATCH_BLOCK, &done, appdata_ptr);
		if(context_pam2.finished == 0)
			debug("extra packet during conversation");
	}

	if(context_pam2.num_received == context_pam2.num_expected) {
		*resp = context_pam2.responses;
		return PAM_SUCCESS;
	} else
		return PAM_CONV_ERR;
}

void
input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	unsigned int nresp = 0, rlen = 0, i = 0;
	char *resp;

	if (authctxt == NULL)
		fatal("input_userauth_info_response_pam: no authentication context");

	nresp = packet_get_int();	/* Number of responses. */
	debug("got %d responses", nresp);


	if (nresp != context_pam2.num_expected)
		fatal("%s: Received incorrect number of responses "
		    "(expected %u, received %u)", __func__, nresp,
		    context_pam2.num_expected);

	if (nresp > 100)
		fatal("%s: too many replies", __func__);

	for (i = 0; i < nresp; i++) {
		int j = context_pam2.prompts[i];

		resp = packet_get_string(&rlen);
		context_pam2.responses[j].resp_retcode = PAM_SUCCESS;
		context_pam2.responses[j].resp = xstrdup(resp);
		xfree(resp);
		context_pam2.num_received++;
	}

	context_pam2.finished = 1;

	packet_check_eom();
}

#endif