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1.1 root 1: /*
2: * tftp.c - a simple, read-only tftp server for qemu
1.1.1.2 root 3: *
1.1 root 4: * Copyright (c) 2004 Magnus Damm <[email protected]>
1.1.1.2 root 5: *
1.1 root 6: * Permission is hereby granted, free of charge, to any person obtaining a copy
7: * of this software and associated documentation files (the "Software"), to deal
8: * in the Software without restriction, including without limitation the rights
9: * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10: * copies of the Software, and to permit persons to whom the Software is
11: * furnished to do so, subject to the following conditions:
12: *
13: * The above copyright notice and this permission notice shall be included in
14: * all copies or substantial portions of the Software.
15: *
16: * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17: * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19: * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20: * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21: * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22: * THE SOFTWARE.
23: */
24:
25: #include <slirp.h>
1.1.1.4 root 26: #include "qemu-common.h"
1.1 root 27:
1.1.1.4 root 28: static inline int tftp_session_in_use(struct tftp_session *spt)
29: {
30: return (spt->slirp != NULL);
31: }
1.1 root 32:
1.1.1.4 root 33: static inline void tftp_session_update(struct tftp_session *spt)
1.1 root 34: {
35: spt->timestamp = curtime;
36: }
37:
38: static void tftp_session_terminate(struct tftp_session *spt)
39: {
1.1.1.4 root 40: qemu_free(spt->filename);
41: spt->slirp = NULL;
1.1 root 42: }
43:
1.1.1.4 root 44: static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
1.1 root 45: {
46: struct tftp_session *spt;
47: int k;
48:
49: for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
1.1.1.4 root 50: spt = &slirp->tftp_sessions[k];
1.1 root 51:
1.1.1.4 root 52: if (!tftp_session_in_use(spt))
1.1 root 53: goto found;
54:
55: /* sessions time out after 5 inactive seconds */
1.1.1.4 root 56: if ((int)(curtime - spt->timestamp) > 5000) {
57: qemu_free(spt->filename);
1.1 root 58: goto found;
1.1.1.4 root 59: }
1.1 root 60: }
61:
62: return -1;
63:
64: found:
65: memset(spt, 0, sizeof(*spt));
66: memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
67: spt->client_port = tp->udp.uh_sport;
1.1.1.4 root 68: spt->slirp = slirp;
1.1 root 69:
70: tftp_session_update(spt);
71:
72: return k;
73: }
74:
1.1.1.4 root 75: static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
1.1 root 76: {
77: struct tftp_session *spt;
78: int k;
79:
80: for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
1.1.1.4 root 81: spt = &slirp->tftp_sessions[k];
1.1 root 82:
1.1.1.4 root 83: if (tftp_session_in_use(spt)) {
1.1 root 84: if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
85: if (spt->client_port == tp->udp.uh_sport) {
86: return k;
87: }
88: }
89: }
90: }
91:
92: return -1;
93: }
94:
1.1.1.6 ! root 95: static int tftp_read_data(struct tftp_session *spt, uint16_t block_nr,
! 96: uint8_t *buf, int len)
1.1 root 97: {
98: int fd;
99: int bytes_read = 0;
100:
1.1.1.4 root 101: fd = open(spt->filename, O_RDONLY | O_BINARY);
1.1 root 102:
103: if (fd < 0) {
104: return -1;
105: }
106:
107: if (len) {
108: lseek(fd, block_nr * 512, SEEK_SET);
109:
110: bytes_read = read(fd, buf, len);
111: }
112:
113: close(fd);
114:
115: return bytes_read;
116: }
117:
1.1.1.2 root 118: static int tftp_send_oack(struct tftp_session *spt,
119: const char *key, uint32_t value,
120: struct tftp_t *recv_tp)
121: {
122: struct sockaddr_in saddr, daddr;
123: struct mbuf *m;
124: struct tftp_t *tp;
125: int n = 0;
126:
1.1.1.4 root 127: m = m_get(spt->slirp);
1.1.1.2 root 128:
129: if (!m)
130: return -1;
131:
132: memset(m->m_data, 0, m->m_size);
133:
134: m->m_data += IF_MAXLINKHDR;
135: tp = (void *)m->m_data;
136: m->m_data += sizeof(struct udpiphdr);
137:
138: tp->tp_op = htons(TFTP_OACK);
1.1.1.3 root 139: n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
140: key) + 1;
141: n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
142: value) + 1;
1.1.1.2 root 143:
144: saddr.sin_addr = recv_tp->ip.ip_dst;
145: saddr.sin_port = recv_tp->udp.uh_dport;
146:
147: daddr.sin_addr = spt->client_ip;
148: daddr.sin_port = spt->client_port;
149:
150: m->m_len = sizeof(struct tftp_t) - 514 + n -
151: sizeof(struct ip) - sizeof(struct udphdr);
152: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
153:
154: return 0;
155: }
156:
1.1.1.4 root 157: static void tftp_send_error(struct tftp_session *spt,
1.1.1.6 ! root 158: uint16_t errorcode, const char *msg,
1.1.1.4 root 159: struct tftp_t *recv_tp)
1.1 root 160: {
161: struct sockaddr_in saddr, daddr;
162: struct mbuf *m;
163: struct tftp_t *tp;
164:
1.1.1.4 root 165: m = m_get(spt->slirp);
1.1 root 166:
167: if (!m) {
1.1.1.4 root 168: goto out;
1.1 root 169: }
170:
171: memset(m->m_data, 0, m->m_size);
172:
1.1.1.2 root 173: m->m_data += IF_MAXLINKHDR;
1.1 root 174: tp = (void *)m->m_data;
175: m->m_data += sizeof(struct udpiphdr);
1.1.1.2 root 176:
1.1 root 177: tp->tp_op = htons(TFTP_ERROR);
178: tp->x.tp_error.tp_error_code = htons(errorcode);
1.1.1.3 root 179: pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
1.1 root 180:
181: saddr.sin_addr = recv_tp->ip.ip_dst;
182: saddr.sin_port = recv_tp->udp.uh_dport;
183:
184: daddr.sin_addr = spt->client_ip;
185: daddr.sin_port = spt->client_port;
186:
1.1.1.2 root 187: m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
1.1 root 188: sizeof(struct ip) - sizeof(struct udphdr);
189:
190: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
191:
1.1.1.4 root 192: out:
1.1 root 193: tftp_session_terminate(spt);
194: }
195:
1.1.1.2 root 196: static int tftp_send_data(struct tftp_session *spt,
1.1.1.6 ! root 197: uint16_t block_nr,
1.1 root 198: struct tftp_t *recv_tp)
199: {
200: struct sockaddr_in saddr, daddr;
201: struct mbuf *m;
202: struct tftp_t *tp;
203: int nobytes;
204:
205: if (block_nr < 1) {
206: return -1;
207: }
208:
1.1.1.4 root 209: m = m_get(spt->slirp);
1.1 root 210:
211: if (!m) {
212: return -1;
213: }
214:
215: memset(m->m_data, 0, m->m_size);
216:
1.1.1.2 root 217: m->m_data += IF_MAXLINKHDR;
1.1 root 218: tp = (void *)m->m_data;
219: m->m_data += sizeof(struct udpiphdr);
1.1.1.2 root 220:
1.1 root 221: tp->tp_op = htons(TFTP_DATA);
222: tp->x.tp_data.tp_block_nr = htons(block_nr);
223:
224: saddr.sin_addr = recv_tp->ip.ip_dst;
225: saddr.sin_port = recv_tp->udp.uh_dport;
226:
227: daddr.sin_addr = spt->client_ip;
228: daddr.sin_port = spt->client_port;
229:
230: nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
231:
232: if (nobytes < 0) {
233: m_free(m);
234:
235: /* send "file not found" error back */
236:
237: tftp_send_error(spt, 1, "File not found", tp);
238:
239: return -1;
240: }
241:
1.1.1.2 root 242: m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
1.1 root 243: sizeof(struct ip) - sizeof(struct udphdr);
244:
245: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
246:
247: if (nobytes == 512) {
248: tftp_session_update(spt);
249: }
250: else {
251: tftp_session_terminate(spt);
252: }
253:
254: return 0;
255: }
256:
1.1.1.4 root 257: static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
1.1 root 258: {
259: struct tftp_session *spt;
1.1.1.4 root 260: int s, k;
261: size_t prefix_len;
262: char *req_fname;
1.1 root 263:
1.1.1.5 root 264: /* check if a session already exists and if so terminate it */
265: s = tftp_session_find(slirp, tp);
266: if (s >= 0) {
267: tftp_session_terminate(&slirp->tftp_sessions[s]);
268: }
269:
1.1.1.4 root 270: s = tftp_session_allocate(slirp, tp);
1.1 root 271:
272: if (s < 0) {
273: return;
274: }
275:
1.1.1.4 root 276: spt = &slirp->tftp_sessions[s];
277:
278: /* unspecifed prefix means service disabled */
279: if (!slirp->tftp_prefix) {
280: tftp_send_error(spt, 2, "Access violation", tp);
281: return;
282: }
1.1 root 283:
1.1.1.4 root 284: /* skip header fields */
285: k = 0;
286: pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
287:
288: /* prepend tftp_prefix */
289: prefix_len = strlen(slirp->tftp_prefix);
290: spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
291: memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
292: spt->filename[prefix_len] = '/';
1.1 root 293:
294: /* get name */
1.1.1.4 root 295: req_fname = spt->filename + prefix_len + 1;
1.1 root 296:
1.1.1.4 root 297: while (1) {
298: if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
299: tftp_send_error(spt, 2, "Access violation", tp);
1.1 root 300: return;
301: }
1.1.1.4 root 302: req_fname[k] = (char)tp->x.tp_buf[k];
303: if (req_fname[k++] == '\0') {
1.1 root 304: break;
305: }
306: }
1.1.1.2 root 307:
1.1 root 308: /* check mode */
1.1.1.4 root 309: if ((pktlen - k) < 6) {
310: tftp_send_error(spt, 2, "Access violation", tp);
1.1 root 311: return;
312: }
1.1.1.2 root 313:
1.1.1.4 root 314: if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
1.1 root 315: tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
316: return;
317: }
318:
1.1.1.2 root 319: k += 6; /* skipping octet */
320:
1.1 root 321: /* do sanity checks on the filename */
1.1.1.4 root 322: if (!strncmp(req_fname, "../", 3) ||
323: req_fname[strlen(req_fname) - 1] == '/' ||
324: strstr(req_fname, "/../")) {
1.1 root 325: tftp_send_error(spt, 2, "Access violation", tp);
326: return;
327: }
328:
329: /* check if the file exists */
1.1.1.4 root 330: if (tftp_read_data(spt, 0, NULL, 0) < 0) {
1.1 root 331: tftp_send_error(spt, 1, "File not found", tp);
332: return;
333: }
334:
1.1.1.4 root 335: if (tp->x.tp_buf[pktlen - 1] != 0) {
1.1.1.2 root 336: tftp_send_error(spt, 2, "Access violation", tp);
337: return;
338: }
339:
1.1.1.4 root 340: while (k < pktlen) {
1.1.1.2 root 341: const char *key, *value;
342:
1.1.1.4 root 343: key = (const char *)&tp->x.tp_buf[k];
1.1.1.2 root 344: k += strlen(key) + 1;
345:
1.1.1.4 root 346: if (k >= pktlen) {
1.1.1.2 root 347: tftp_send_error(spt, 2, "Access violation", tp);
348: return;
349: }
350:
1.1.1.4 root 351: value = (const char *)&tp->x.tp_buf[k];
1.1.1.2 root 352: k += strlen(value) + 1;
353:
354: if (strcmp(key, "tsize") == 0) {
355: int tsize = atoi(value);
356: struct stat stat_p;
357:
1.1.1.4 root 358: if (tsize == 0) {
359: if (stat(spt->filename, &stat_p) == 0)
1.1.1.2 root 360: tsize = stat_p.st_size;
361: else {
362: tftp_send_error(spt, 1, "File not found", tp);
363: return;
364: }
365: }
366:
367: tftp_send_oack(spt, "tsize", tsize, tp);
1.1.1.5 root 368: return;
1.1.1.2 root 369: }
370: }
371:
1.1 root 372: tftp_send_data(spt, 1, tp);
373: }
374:
1.1.1.4 root 375: static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
1.1 root 376: {
377: int s;
378:
1.1.1.4 root 379: s = tftp_session_find(slirp, tp);
1.1 root 380:
381: if (s < 0) {
382: return;
383: }
384:
1.1.1.4 root 385: if (tftp_send_data(&slirp->tftp_sessions[s],
1.1.1.2 root 386: ntohs(tp->x.tp_data.tp_block_nr) + 1,
1.1 root 387: tp) < 0) {
388: return;
389: }
390: }
391:
1.1.1.5 root 392: static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
393: {
394: int s;
395:
396: s = tftp_session_find(slirp, tp);
397:
398: if (s < 0) {
399: return;
400: }
401:
402: tftp_session_terminate(&slirp->tftp_sessions[s]);
403: }
404:
1.1 root 405: void tftp_input(struct mbuf *m)
406: {
407: struct tftp_t *tp = (struct tftp_t *)m->m_data;
408:
409: switch(ntohs(tp->tp_op)) {
410: case TFTP_RRQ:
1.1.1.4 root 411: tftp_handle_rrq(m->slirp, tp, m->m_len);
1.1 root 412: break;
413:
414: case TFTP_ACK:
1.1.1.4 root 415: tftp_handle_ack(m->slirp, tp, m->m_len);
1.1 root 416: break;
1.1.1.5 root 417:
418: case TFTP_ERROR:
419: tftp_handle_error(m->slirp, tp, m->m_len);
420: break;
1.1 root 421: }
422: }
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