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Annotation of /trunk/ttssh2/ttxssh/pkt.c

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Revision 10962 - (hide annotations) (download) (as text)
Sun Oct 8 06:17:15 2023 UTC (5 months ago) by zmatsuo
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File size: 11696 byte(s) 
不要な受信処理停止を削除、削除関数のプロトタイプ削除、コメント修正

- r10960の修正
1 maya 3227 /*
2 doda 6841 * Copyright (c) 1998-2001, Robert O'Callahan
3 nmaya 9048 * (C) 2004- TeraTerm Project
4 doda 6841 * All rights reserved.
5     *
6     * Redistribution and use in source and binary forms, with or without
7     * modification, are permitted provided that the following conditions
8     * are met:
9     *
10     * 1. Redistributions of source code must retain the above copyright
11     * notice, this list of conditions and the following disclaimer.
12     * 2. Redistributions in binary form must reproduce the above copyright
13     * notice, this list of conditions and the following disclaimer in the
14     * documentation and/or other materials provided with the distribution.
15     * 3. The name of the author may not be used to endorse or promote products
16     * derived from this software without specific prior written permission.
17     *
18     * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
19     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21     * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28     */
29 maya 3227
30     /*
31     This code is copyright (C) 1998-1999 Robert O'Callahan.
32     See LICENSE.TXT for the license.
33     */
34    
35     #include "ttxssh.h"
36     #include "util.h"
37     #include "pkt.h"
38    
39     #define READAMOUNT CHAN_SES_WINDOW_DEFAULT
40    
41     void PKT_init(PTInstVar pvar)
42     {
43     buf_create(&pvar->pkt_state.buf, &pvar->pkt_state.buflen);
44     pvar->pkt_state.datastart = 0;
45     pvar->pkt_state.datalen = 0;
46     pvar->pkt_state.seen_server_ID = FALSE;
47     pvar->pkt_state.seen_newline = FALSE;
48     pvar->pkt_state.predecrypted_packet = FALSE;
49     }
50    
51     /* Read some data, leave no more than up_to_amount bytes in the buffer,
52     return the number of bytes read or -1 on error or blocking. */
53     static int recv_data(PTInstVar pvar, unsigned long up_to_amount)
54     {
55     int amount_read;
56    
57     /* Shuffle data to the start of the buffer */
58     if (pvar->pkt_state.datastart != 0) {
59     memmove(pvar->pkt_state.buf,
60     pvar->pkt_state.buf + pvar->pkt_state.datastart,
61     pvar->pkt_state.datalen);
62     pvar->pkt_state.datastart = 0;
63     }
64    
65 doda 6966 buf_ensure_size(&pvar->pkt_state.buf, &pvar->pkt_state.buflen, up_to_amount);
66 maya 3227
67     _ASSERT(pvar->pkt_state.buf != NULL);
68    
69     amount_read = (pvar->Precv) (pvar->socket,
70 doda 6966 pvar->pkt_state.buf + pvar->pkt_state.datalen,
71 maya 3227 up_to_amount - pvar->pkt_state.datalen,
72     0);
73    
74     if (amount_read > 0) {
75     /* Update seen_newline if necessary */
76 doda 6966 if (!pvar->pkt_state.seen_server_ID && !pvar->pkt_state.seen_newline) {
77 maya 3227 int i;
78    
79     for (i = 0; i < amount_read; i++) {
80 doda 6966 if (pvar->pkt_state.buf[pvar->pkt_state.datalen + i] == '\n') {
81 maya 3227 pvar->pkt_state.seen_newline = 1;
82     }
83     }
84     }
85     pvar->pkt_state.datalen += amount_read;
86     }
87    
88     return amount_read;
89     }
90    
91     // ���s�R�[�h���o��������������
92     static int recv_line_data(PTInstVar pvar)
93     {
94     int amount_read;
95     char buf[256];
96     size_t up_to_amount = sizeof(buf);
97     int i;
98    
99     /* Shuffle data to the start of the buffer */
100     if (pvar->pkt_state.datastart != 0) {
101     memmove(pvar->pkt_state.buf,
102     pvar->pkt_state.buf + pvar->pkt_state.datastart,
103     pvar->pkt_state.datalen);
104     pvar->pkt_state.datastart = 0;
105     }
106    
107 doda 6966 buf_ensure_size(&pvar->pkt_state.buf, &pvar->pkt_state.buflen, up_to_amount);
108 maya 3227
109     for (i = 0 ; i < (int)up_to_amount ; i++) {
110 doda 6966 amount_read = (pvar->Precv) (pvar->socket, &buf[i], 1, 0);
111 maya 3227 if (amount_read != 1) {
112     return 0; // error
113 zmatsuo 10618 }
114 maya 3227
115     pvar->pkt_state.datalen += amount_read;
116    
117     if (buf[i] == '\n') { // 0x0a
118     buf[i+1] = 0;
119     break;
120     }
121     }
122     amount_read = i + 1; // ���������T�C�Y�iLF�������j
123     memcpy(pvar->pkt_state.buf, buf, amount_read);
124    
125     pvar->pkt_state.seen_newline = 1;
126    
127     return amount_read;
128     }
129    
130     /* This function does two things:
131     -- reads data from the sshd and feeds the SSH protocol packets to ssh.c
132     -- copies any available decrypted session data into the application buffer
133     */
134 doda 6801 int PKT_recv(PTInstVar pvar, char *buf, int buflen)
135 maya 3227 {
136     int amount_in_buf = 0;
137     BOOL connection_closed = FALSE;
138    
139     while (SSH_is_any_payload(pvar) ? buflen > 0 : !connection_closed) {
140     if (SSH_is_any_payload(pvar)) {
141     /* ssh.c has some session data for us to give to Tera Term. */
142     int grabbed = SSH_extract_payload(pvar, buf, buflen);
143    
144     amount_in_buf += grabbed;
145     buf += grabbed;
146     buflen -= grabbed;
147 doda 6968 }
148     else if (!pvar->pkt_state.seen_server_ID && (pvar->pkt_state.seen_newline || pvar->pkt_state.datalen >= 255)) {
149     /*
150     * We're looking for the initial ID string and either we've seen the
151     * terminating newline, or we've exceeded the limit at which we should see a newline.
152     */
153 maya 3227 unsigned int i;
154    
155 doda 6966 for (i = 0; pvar->pkt_state.buf[i] != '\n' && i < pvar->pkt_state.datalen; i++) {
156 maya 3227 }
157     if (pvar->pkt_state.buf[i] == '\n') {
158     i++;
159     }
160    
161     // SSH�T�[�o���o�[�W�����`�F�b�N���s��
162     if (SSH_handle_server_ID(pvar, pvar->pkt_state.buf, i)) {
163     pvar->pkt_state.seen_server_ID = 1;
164    
165 doda 6966 if (SSHv2(pvar)) {
166 maya 3227 // send Key Exchange Init
167     SSH2_send_kexinit(pvar);
168     }
169 maya 4549 } else {
170     // reset flag to re-read server ID (2008.1.24 yutaka)
171     pvar->pkt_state.seen_newline = 0;
172 maya 3227 }
173    
174     pvar->pkt_state.datastart += i;
175     pvar->pkt_state.datalen -= i;
176 doda 6968 }
177 doda 6982 else if (pvar->pkt_state.seen_server_ID && pvar->pkt_state.datalen >= SSH_get_min_packet_size(pvar)) {
178 doda 6966 char *data = pvar->pkt_state.buf + pvar->pkt_state.datastart;
179 nmaya 9255 uint32 padding_size = 0;
180     uint32 pktsize = 0;
181 maya 3227 uint32 total_packet_size;
182 doda 6969 struct Mac *mac = &pvar->ssh2_keys[MODE_IN].mac;
183 doda 6985 struct Enc *enc = &pvar->ssh2_keys[MODE_IN].enc;
184 nmaya 9255 int authlen = 0, aadlen = 0;
185 maya 3227
186 nmaya 9255 if (SSHv2(pvar)) {
187     /*
188     * pktsize
189     * uint32 packet_length
190     * ��
191     * byte padding_length
192     * byte[n1] payload; n1 = packet_length - padding_length - 1
193     * byte[n2] random padding; n2 = padding_length
194     * �����������v��
195     * byte[m] mac (Message Authentication Code - MAC); m = mac_length
196     * �����������������B
197     * cf. RFC 4253 6. Binary Packet Protocol
198     */
199    
200     if (enc && enc->auth_len > 0) {
201     authlen = enc->auth_len;
202     }
203    
204     /*
205     * | | lead 4 bytes are encrypted | aadlen |
206     * Encryption type
207     * enc->auth_len > 0 | AEAD | AES-GCM ... no | 4 | (2)
208     * | | chacha20-poly1305 ... yes | 4 | (1) (2)
209     * enc->auth_len == 0 | not AEAD | depends on MAC type | <- |
210     * MAC type
211     * mac->etm == true | EtM | no | 4 |
212     * mac->etm == false | E&M | yes | 0 |
213     * (1) lead 4 bytes are encrypted separately from main part.
214     * (2) implicit MAC type of AEAD is EtM
215     */
216     /*
217     * aadlen: Additional Authenticated Data Length
218     * MAC �������������f�[�^�����������������������A"MAC �������������f�[�^������"���T�C�Y
219     * ���������� packet_length ���Auint32 (4�o�C�g)
220 zmatsuo 10618 *
221 nmaya 9255 * - ������ MAC ���� (E&M) �����p�P�b�g������������������������������ aadlen �� 0 �������B
222     * - EtM ������ MAC �� AEAD �� AES-GCM �����A�p�P�b�g��������������������������
223     * aadlen �� 4 �������B
224     * - AEAD �� chacha20-poly1305 �����p�P�b�g�����������������������AMAC �������������f�[�^
225     * ������������������������ aadlen �� 4 �������B
226 zmatsuo 10618 *
227 nmaya 9255 */
228     if ((mac && mac->etm) || authlen > 0) {
229     aadlen = 4;
230     }
231    
232     if (authlen > 0 &&
233     pvar->cc[MODE_IN]->cipher->id == SSH2_CIPHER_CHACHAPOLY) {
234     /*
235     * AEAD �� chacha20-poly1305 �����p�P�b�g�����������������������������B
236     * ���������������������������Adata �������������������������B
237     */
238     chachapoly_get_length(pvar->cc[MODE_IN]->cp_ctx, &pktsize,
239     pvar->ssh_state.receiver_sequence_number,
240     data, pvar->pkt_state.datalen);
241     }
242     else if (authlen == 0 &&
243     aadlen == 0 &&
244     !pvar->pkt_state.predecrypted_packet && aadlen == 0) {
245     /*
246     * AEAD ������ E&M (aadlen �� 0) �������A�����������������p�P�b�g����
247     * �m���K�v���L�������A������ 1 �u���b�N�������O�����������B
248     */
249     SSH_predecrypt_packet(pvar, data);
250     pvar->pkt_state.predecrypted_packet = TRUE;
251    
252     pktsize = get_uint32_MSBfirst(data);
253     }
254     else {
255     /*
256     * EtM ������ MAC ���AAEAD �� AES-GCM ���������������������������B
257     */
258     pktsize = get_uint32_MSBfirst(data);
259     }
260 doda 6985 }
261     else {
262 nmaya 9255 pktsize = get_uint32_MSBfirst(data);
263 doda 6985 }
264 doda 6969
265 maya 3227 if (SSHv1(pvar)) {
266 doda 6983 // SSH1 �����p�P�b�g�����l���� padding �����������������������B
267     // ���� padding ���������������p�P�b�g���������������A�p�P�b�g�����l�����v�Z�����B
268 nmaya 9255 padding_size = 8 - (pktsize % 8);
269 maya 3227
270 nmaya 9255 // ���~�������� pktsize �� padding_size ���l�������������������O���������������B
271     pktsize += padding_size;
272 maya 3227 }
273    
274 nmaya 9255 // �p�P�b�g(TCP�y�C���[�h)���S�����T�C�Y���A
275     // 4�i�p�P�b�g�����T�C�Y�j+�p�P�b�g���i+MAC���T�C�Y�j�������B
276     total_packet_size = 4 + pktsize + SSH_get_authdata_size(pvar, MODE_IN);
277 maya 3227
278     if (total_packet_size <= pvar->pkt_state.datalen) {
279 doda 6972 // ���M�����f�[�^���\���L���������p�P�b�g�����������s��
280 doda 6968 if (SSHv1(pvar)) {
281 doda 6983 // SSH1 �� EtM ������ (�������� MAC �������� CRC ���g��)
282 nmaya 9255 SSH1_handle_packet(pvar, data, pktsize, padding_size);
283 doda 6968 }
284     else {
285 doda 6983 // SSH2 �����������_���� padding ���������������������������������������A
286     // padding �����n�������A�K�v���������������������������B
287 nmaya 9255 SSH2_handle_packet(pvar, data, pktsize, aadlen, authlen);
288 doda 6968 }
289 doda 6972
290 maya 3227 pvar->pkt_state.predecrypted_packet = FALSE;
291     pvar->pkt_state.datastart += total_packet_size;
292     pvar->pkt_state.datalen -= total_packet_size;
293    
294 doda 6983 }
295     else if (total_packet_size > PACKET_MAX_SIZE) {
296 doda 6972 // �p�P�b�g�������������������������I�������B
297     // �����������������v�����������s���p�P�b�g���������������������������B
298 maya 3227 UTIL_get_lang_msg("MSG_PKT_OVERSIZED_ERROR", pvar,
299 maya 4549 "Oversized packet received from server; connection will close.");
300 zmatsuo 10618 notify_fatal_error(pvar, pvar->UIMsg, TRUE);
301 doda 6983 }
302     else {
303 doda 6966 int amount_read = recv_data(pvar, max(total_packet_size, READAMOUNT));
304 maya 3227
305     if (amount_read == SOCKET_ERROR) {
306     if (amount_in_buf == 0) {
307     return SOCKET_ERROR;
308     } else {
309     return amount_in_buf;
310     }
311     } else {
312     if (amount_read == 0) {
313     connection_closed = TRUE;
314     }
315     }
316     }
317     } else {
318 doda 6966 // �p�P�b�g�����M
319 maya 3227 int amount_read;
320    
321 doda 6966 amount_read = recv_data(pvar, READAMOUNT);
322 maya 3227
323     if (amount_read == SOCKET_ERROR) {
324     if (amount_in_buf == 0) {
325     return SOCKET_ERROR;
326     } else {
327     return amount_in_buf;
328     }
329     } else if (amount_read == 0) {
330     connection_closed = TRUE;
331     }
332     }
333    
334     if (pvar->fatal_error) {
335     return amount_in_buf;
336     }
337     }
338    
339     if (SSH_is_any_payload(pvar)) {
340 doda 6966 PostMessage(pvar->NotificationWindow, WM_USER_COMMNOTIFY, pvar->socket, MAKELPARAM(FD_READ, 0));
341 maya 3227 }
342    
343     return amount_in_buf;
344     }
345    
346     void PKT_end(PTInstVar pvar)
347     {
348     buf_destroy(&pvar->pkt_state.buf, &pvar->pkt_state.buflen);
349     }
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