summaryrefslogtreecommitdiffstats
path: root/libvncserver/rfbssl_gnutls.c
blob: e58cdad78d0c685805031e1d4ac85ad5f2185ddf (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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
/*
 * rfbssl_gnutls.c - Secure socket funtions (gnutls version)
 */

/*
 *  Copyright (C) 2011 Gernot Tenchio
 *
 *  This is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This software is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this software; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 *  USA.
 */

#include "rfbssl.h"
#include <gnutls/gnutls.h>
#include <errno.h>

struct rfbssl_ctx {
    char peekbuf[2048];
    int peeklen;
    int peekstart;
    gnutls_session_t session;
    gnutls_certificate_credentials_t x509_cred;
    gnutls_dh_params_t dh_params;
#ifdef I_LIKE_RSA_PARAMS_THAT_MUCH
    gnutls_rsa_params_t rsa_params;
#endif
};

void rfbssl_log_func(int level, const char *msg)
{
    rfbErr("SSL: %s", msg);
}

static void rfbssl_error(const char *msg, int e)
{
    rfbErr("%s: %s (%ld)\n", msg, gnutls_strerror(e), e);
}

static int rfbssl_init_session(struct rfbssl_ctx *ctx, int fd)
{
    gnutls_session_t session;
    int ret;

    if (!GNUTLS_E_SUCCESS == (ret = gnutls_init(&session, GNUTLS_SERVER))) {
      /* */
    } else if (!GNUTLS_E_SUCCESS == (ret = gnutls_priority_set_direct(session, "EXPORT", NULL))) {
      /* */
    } else if (!GNUTLS_E_SUCCESS == (ret = gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, ctx->x509_cred))) {
      /* */
    } else {
      gnutls_session_enable_compatibility_mode(session);
      gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t)(uintptr_t)fd);
      ctx->session = session;
    }
    return ret;
}

static int generate_dh_params(struct rfbssl_ctx *ctx)
{
    int ret;
    if (GNUTLS_E_SUCCESS == (ret = gnutls_dh_params_init(&ctx->dh_params)))
	ret = gnutls_dh_params_generate2(ctx->dh_params, 1024);
    return ret;
}

#ifdef I_LIKE_RSA_PARAMS_THAT_MUCH
static int generate_rsa_params(struct rfbssl_ctx *ctx)
{
    int ret;
    if (GNUTLS_E_SUCCESS == (ret = gnutls_rsa_params_init(&ctx->rsa_params)))
	ret = gnutls_rsa_params_generate2(ctx->rsa_params, 512);
    return ret;
}
#endif

struct rfbssl_ctx *rfbssl_init_global(char *key, char *cert)
{
    int ret = GNUTLS_E_SUCCESS;
    struct rfbssl_ctx *ctx = NULL;

    if (NULL == (ctx = malloc(sizeof(struct rfbssl_ctx)))) {
	ret = GNUTLS_E_MEMORY_ERROR;
    } else if (!GNUTLS_E_SUCCESS == (ret = gnutls_global_init())) {
	/* */
    } else if (!GNUTLS_E_SUCCESS == (ret = gnutls_certificate_allocate_credentials(&ctx->x509_cred))) {
	/* */
    } else if ((ret = gnutls_certificate_set_x509_trust_file(ctx->x509_cred, cert, GNUTLS_X509_FMT_PEM)) < 0) {
	/* */
    } else if (!GNUTLS_E_SUCCESS == (ret = gnutls_certificate_set_x509_key_file(ctx->x509_cred, cert, key, GNUTLS_X509_FMT_PEM))) {
	/* */
    } else if (!GNUTLS_E_SUCCESS == (ret = generate_dh_params(ctx))) {
	/* */
#ifdef I_LIKE_RSA_PARAMS_THAT_MUCH
    } else if (!GNUTLS_E_SUCCESS == (ret = generate_rsa_params(ctx))) {
	/* */
#endif
    } else {
	gnutls_global_set_log_function(rfbssl_log_func);
	gnutls_global_set_log_level(1);
	gnutls_certificate_set_dh_params(ctx->x509_cred, ctx->dh_params);
	/* newly allocated memory should be initialized, at least where it is important */
	ctx->peekstart = ctx->peeklen = 0;
	return ctx;
    }

    free(ctx);
    return NULL;
}

int rfbssl_init(rfbClientPtr cl)
{
    int ret = -1;
    struct rfbssl_ctx *ctx;
    char *keyfile;
    if (!(keyfile = cl->screen->sslkeyfile))
	keyfile = cl->screen->sslcertfile;

    if (NULL == (ctx = rfbssl_init_global(keyfile,  cl->screen->sslcertfile))) {
	/* */
    } else if (GNUTLS_E_SUCCESS != (ret = rfbssl_init_session(ctx, cl->sock))) {
	/* */
    } else {
	while (GNUTLS_E_SUCCESS != (ret = gnutls_handshake(ctx->session))) {
	    if (ret == GNUTLS_E_AGAIN)
		continue;
	    break;
	}
    }

    if (ret != GNUTLS_E_SUCCESS) {
	rfbssl_error(__func__, ret);
    } else {
	cl->sslctx = (rfbSslCtx *)ctx;
	rfbLog("%s protocol initialized\n", gnutls_protocol_get_name(gnutls_protocol_get_version(ctx->session)));
    }
    return ret;
}

static int rfbssl_do_read(rfbClientPtr cl, char *buf, int bufsize)
{
    struct rfbssl_ctx *ctx = (struct rfbssl_ctx *)cl->sslctx;
    int ret;

    while ((ret = gnutls_record_recv(ctx->session, buf, bufsize)) < 0) {
	if (ret == GNUTLS_E_AGAIN) {
	    /* continue */
	} else if (ret == GNUTLS_E_INTERRUPTED) {
	    /* continue */
	} else {
	    break;
	}
    }

    if (ret < 0) {
	rfbssl_error(__func__, ret);
	errno = EIO;
	ret = -1;
    }

    return ret < 0 ? -1 : ret;
}

int rfbssl_write(rfbClientPtr cl, const char *buf, int bufsize)
{
    struct rfbssl_ctx *ctx = (struct rfbssl_ctx *)cl->sslctx;
    int ret;

    while ((ret = gnutls_record_send(ctx->session, buf, bufsize)) < 0) {
	if (ret == GNUTLS_E_AGAIN) {
	    /* continue */
	} else if (ret == GNUTLS_E_INTERRUPTED) {
	    /* continue */
	} else {
	    break;
	}
    }

    if (ret < 0)
	rfbssl_error(__func__, ret);

    return ret;
}

static void rfbssl_gc_peekbuf(struct rfbssl_ctx *ctx, int bufsize)
{
    if (ctx->peekstart) {
	int spaceleft = sizeof(ctx->peekbuf) - ctx->peeklen - ctx->peekstart;
	if (spaceleft < bufsize) {
	    memmove(ctx->peekbuf, ctx->peekbuf + ctx->peekstart, ctx->peeklen);
	    ctx->peekstart = 0;
	}
    }
}

static int __rfbssl_read(rfbClientPtr cl, char *buf, int bufsize, int peek)
{
    int ret = 0;
    struct rfbssl_ctx *ctx = (struct rfbssl_ctx *)cl->sslctx;

    rfbssl_gc_peekbuf(ctx, bufsize);

    if (ctx->peeklen) {
	/* If we have any peek data, simply return that. */
	ret = bufsize < ctx->peeklen ? bufsize : ctx->peeklen;
	memcpy (buf, ctx->peekbuf + ctx->peekstart, ret);
	if (!peek) {
	    ctx->peeklen -= ret;
	    if (ctx->peeklen != 0)
		ctx->peekstart += ret;
	    else
		ctx->peekstart = 0;
	}
    }

    if (ret < bufsize) {
	int n;
	/* read the remaining data */
	if ((n = rfbssl_do_read(cl, buf + ret, bufsize - ret)) <= 0) {
	    rfbErr("rfbssl_%s: %s error\n", __func__, peek ? "peek" : "read");
	    return n;
	}
	if (peek) {
	    memcpy(ctx->peekbuf + ctx->peekstart + ctx->peeklen, buf + ret, n);
	    ctx->peeklen += n;
	}
	ret += n;
    }

    return ret;
}

int rfbssl_read(rfbClientPtr cl, char *buf, int bufsize)
{
    return __rfbssl_read(cl, buf, bufsize, 0);
}

int rfbssl_peek(rfbClientPtr cl, char *buf, int bufsize)
{
    return __rfbssl_read(cl, buf, bufsize, 1);
}

int rfbssl_pending(rfbClientPtr cl)
{
    struct rfbssl_ctx *ctx = (struct rfbssl_ctx *)cl->sslctx;
    int ret = ctx->peeklen;

    if (ret <= 0)
	ret = gnutls_record_check_pending(ctx->session);

    return ret;
}

void rfbssl_destroy(rfbClientPtr cl)
{
    struct rfbssl_ctx *ctx = (struct rfbssl_ctx *)cl->sslctx;
    gnutls_bye(ctx->session, GNUTLS_SHUT_WR);
    gnutls_deinit(ctx->session);
    gnutls_certificate_free_credentials(ctx->x509_cred);
}