1 /* dnsmasq is Copyright (c) 2000-2013 Simon Kelley
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; version 2 dated June, 1991, or
6 (at your option) version 3 dated 29 June, 2007.
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
13 You should have received a copy of the GNU General Public License
14 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 static struct tftp_file
*check_tftp_fileperm(ssize_t
*len
, char *prefix
);
22 static void free_transfer(struct tftp_transfer
*transfer
);
23 static ssize_t
tftp_err(int err
, char *packet
, char *mess
, char *file
);
24 static ssize_t
tftp_err_oops(char *packet
, char *file
);
25 static ssize_t
get_block(char *packet
, struct tftp_transfer
*transfer
);
26 static char *next(char **p
, char *end
);
27 static void sanitise(char *buf
);
42 void tftp_request(struct listener
*listen
, time_t now
)
45 char *packet
= daemon
->packet
;
46 char *filename
, *mode
, *p
, *end
, *opt
;
47 union mysockaddr addr
, peer
;
51 int is_err
= 1, if_index
= 0, mtu
= 0;
53 struct tftp_transfer
*transfer
;
54 int port
= daemon
->start_tftp_port
; /* may be zero to use ephemeral port */
55 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
56 int mtuflag
= IP_PMTUDISC_DONT
;
58 char namebuff
[IF_NAMESIZE
];
60 char *prefix
= daemon
->tftp_prefix
;
61 struct tftp_prefix
*pref
;
62 struct all_addr addra
;
65 struct cmsghdr align
; /* this ensures alignment */
67 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
69 #if defined(HAVE_LINUX_NETWORK)
70 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
71 #elif defined(HAVE_SOLARIS_NETWORK)
72 char control
[CMSG_SPACE(sizeof(unsigned int))];
73 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
74 char control
[CMSG_SPACE(sizeof(struct sockaddr_dl
))];
78 msg
.msg_controllen
= sizeof(control_u
);
79 msg
.msg_control
= control_u
.control
;
82 msg
.msg_namelen
= sizeof(peer
);
86 iov
.iov_base
= packet
;
87 iov
.iov_len
= daemon
->packet_buff_sz
;
89 /* we overwrote the buffer... */
90 daemon
->srv_save
= NULL
;
92 if ((len
= recvmsg(listen
->tftpfd
, &msg
, 0)) < 2)
95 if (option_bool(OPT_NOWILD
))
99 addr
= listen
->iface
->addr
;
100 mtu
= listen
->iface
->mtu
;
101 name
= listen
->iface
->name
;
105 /* we're listening on an address that doesn't appear on an interface,
106 ask the kernel what the socket is bound to */
107 socklen_t tcp_len
= sizeof(union mysockaddr
);
108 if (getsockname(listen
->tftpfd
, (struct sockaddr
*)&addr
, &tcp_len
) == -1)
114 struct cmsghdr
*cmptr
;
116 if (msg
.msg_controllen
< sizeof(struct cmsghdr
))
119 addr
.sa
.sa_family
= listen
->family
;
121 #if defined(HAVE_LINUX_NETWORK)
122 if (listen
->family
== AF_INET
)
123 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
124 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_PKTINFO
)
128 struct in_pktinfo
*p
;
130 p
.c
= CMSG_DATA(cmptr
);
131 addr
.in
.sin_addr
= p
.p
->ipi_spec_dst
;
132 if_index
= p
.p
->ipi_ifindex
;
135 #elif defined(HAVE_SOLARIS_NETWORK)
136 if (listen
->family
== AF_INET
)
137 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
144 p
.c
= CMSG_DATA(cmptr
);
145 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
146 addr
.in
.sin_addr
= *(p
.a
);
147 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
151 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
152 if (listen
->family
== AF_INET
)
153 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
158 struct sockaddr_dl
*s
;
160 p
.c
= CMSG_DATA(cmptr
);
161 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
162 addr
.in
.sin_addr
= *(p
.a
);
163 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
164 if_index
= p
.s
->sdl_index
;
170 if (listen
->family
== AF_INET6
)
172 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
173 if (cmptr
->cmsg_level
== IPPROTO_IPV6
&& cmptr
->cmsg_type
== daemon
->v6pktinfo
)
177 struct in6_pktinfo
*p
;
179 p
.c
= CMSG_DATA(cmptr
);
181 addr
.in6
.sin6_addr
= p
.p
->ipi6_addr
;
182 if_index
= p
.p
->ipi6_ifindex
;
187 if (!indextoname(listen
->tftpfd
, if_index
, namebuff
))
192 addra
.addr
.addr4
= addr
.in
.sin_addr
;
195 if (listen
->family
== AF_INET6
)
196 addra
.addr
.addr6
= addr
.in6
.sin6_addr
;
199 if (daemon
->tftp_interfaces
)
201 /* dedicated tftp interface list */
202 for (tmp
= daemon
->tftp_interfaces
; tmp
; tmp
= tmp
->next
)
203 if (tmp
->name
&& wildcard_match(tmp
->name
, name
))
211 /* Do the same as DHCP */
212 if (!iface_check(listen
->family
, &addra
, name
, NULL
))
214 if (!option_bool(OPT_CLEVERBIND
))
215 enumerate_interfaces(0);
216 if (!loopback_exception(listen
->tftpfd
, listen
->family
, &addra
, name
) &&
217 !label_exception(if_index
, listen
->family
, &addra
) )
222 /* allowed interfaces are the same as for DHCP */
223 for (tmp
= daemon
->dhcp_except
; tmp
; tmp
= tmp
->next
)
224 if (tmp
->name
&& wildcard_match(tmp
->name
, name
))
229 strncpy(ifr
.ifr_name
, name
, IF_NAMESIZE
);
230 if (ioctl(listen
->tftpfd
, SIOCGIFMTU
, &ifr
) != -1)
236 /* check for per-interface prefix */
237 for (pref
= daemon
->if_prefix
; pref
; pref
= pref
->next
)
238 if (strcmp(pref
->interface
, name
) == 0)
239 prefix
= pref
->prefix
;
242 if (listen
->family
== AF_INET
)
244 addr
.in
.sin_port
= htons(port
);
245 #ifdef HAVE_SOCKADDR_SA_LEN
246 addr
.in
.sin_len
= sizeof(addr
.in
);
252 addr
.in6
.sin6_port
= htons(port
);
253 addr
.in6
.sin6_flowinfo
= 0;
254 addr
.in6
.sin6_scope_id
= 0;
255 #ifdef HAVE_SOCKADDR_SA_LEN
256 addr
.in6
.sin6_len
= sizeof(addr
.in6
);
261 if (!(transfer
= whine_malloc(sizeof(struct tftp_transfer
))))
264 if ((transfer
->sockfd
= socket(listen
->family
, SOCK_DGRAM
, 0)) == -1)
270 transfer
->peer
= peer
;
271 transfer
->timeout
= now
+ 2;
272 transfer
->backoff
= 1;
274 transfer
->blocksize
= 512;
275 transfer
->offset
= 0;
276 transfer
->file
= NULL
;
277 transfer
->opt_blocksize
= transfer
->opt_transize
= 0;
278 transfer
->netascii
= transfer
->carrylf
= 0;
280 prettyprint_addr(&peer
, daemon
->addrbuff
);
282 /* if we have a nailed-down range, iterate until we find a free one. */
285 if (bind(transfer
->sockfd
, &addr
.sa
, sa_len(&addr
)) == -1 ||
286 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
287 setsockopt(transfer
->sockfd
, IPPROTO_IP
, IP_MTU_DISCOVER
, &mtuflag
, sizeof(mtuflag
)) == -1 ||
289 !fix_fd(transfer
->sockfd
))
291 if (errno
== EADDRINUSE
&& daemon
->start_tftp_port
!= 0)
293 if (++port
<= daemon
->end_tftp_port
)
295 if (listen
->family
== AF_INET
)
296 addr
.in
.sin_port
= htons(port
);
299 addr
.in6
.sin6_port
= htons(port
);
303 my_syslog(MS_TFTP
| LOG_ERR
, _("unable to get free port for TFTP"));
305 free_transfer(transfer
);
314 if (ntohs(*((unsigned short *)packet
)) != OP_RRQ
||
315 !(filename
= next(&p
, end
)) ||
316 !(mode
= next(&p
, end
)) ||
317 (strcasecmp(mode
, "octet") != 0 && strcasecmp(mode
, "netascii") != 0))
319 len
= tftp_err(ERR_ILL
, packet
, _("unsupported request from %s"), daemon
->addrbuff
);
324 if (strcasecmp(mode
, "netascii") == 0)
325 transfer
->netascii
= 1;
327 while ((opt
= next(&p
, end
)))
329 if (strcasecmp(opt
, "blksize") == 0)
331 if ((opt
= next(&p
, end
)) && !option_bool(OPT_TFTP_NOBLOCK
))
333 transfer
->blocksize
= atoi(opt
);
334 if (transfer
->blocksize
< 1)
335 transfer
->blocksize
= 1;
336 if (transfer
->blocksize
> (unsigned)daemon
->packet_buff_sz
- 4)
337 transfer
->blocksize
= (unsigned)daemon
->packet_buff_sz
- 4;
338 /* 32 bytes for IP, UDP and TFTP headers */
339 if (mtu
!= 0 && transfer
->blocksize
> (unsigned)mtu
- 32)
340 transfer
->blocksize
= (unsigned)mtu
- 32;
341 transfer
->opt_blocksize
= 1;
345 else if (strcasecmp(opt
, "tsize") == 0 && next(&p
, end
) && !transfer
->netascii
)
347 transfer
->opt_transize
= 1;
352 /* cope with backslashes from windows boxen. */
353 for (p
= filename
; *p
; p
++)
356 else if (option_bool(OPT_TFTP_LC
))
359 strcpy(daemon
->namebuff
, "/");
362 if (prefix
[0] == '/')
363 daemon
->namebuff
[0] = 0;
364 strncat(daemon
->namebuff
, prefix
, (MAXDNAME
-1) - strlen(daemon
->namebuff
));
365 if (prefix
[strlen(prefix
)-1] != '/')
366 strncat(daemon
->namebuff
, "/", (MAXDNAME
-1) - strlen(daemon
->namebuff
));
368 if (option_bool(OPT_TFTP_APREF
))
370 size_t oldlen
= strlen(daemon
->namebuff
);
373 strncat(daemon
->namebuff
, daemon
->addrbuff
, (MAXDNAME
-1) - strlen(daemon
->namebuff
));
374 strncat(daemon
->namebuff
, "/", (MAXDNAME
-1) - strlen(daemon
->namebuff
));
376 /* remove unique-directory if it doesn't exist */
377 if (stat(daemon
->namebuff
, &statbuf
) == -1 || !S_ISDIR(statbuf
.st_mode
))
378 daemon
->namebuff
[oldlen
] = 0;
381 /* Absolute pathnames OK if they match prefix */
382 if (filename
[0] == '/')
384 if (strstr(filename
, daemon
->namebuff
) == filename
)
385 daemon
->namebuff
[0] = 0;
390 else if (filename
[0] == '/')
391 daemon
->namebuff
[0] = 0;
392 strncat(daemon
->namebuff
, filename
, (MAXDNAME
-1) - strlen(daemon
->namebuff
));
394 /* check permissions and open file */
395 if ((transfer
->file
= check_tftp_fileperm(&len
, prefix
)))
397 if ((len
= get_block(packet
, transfer
)) == -1)
398 len
= tftp_err_oops(packet
, daemon
->namebuff
);
404 while (sendto(transfer
->sockfd
, packet
, len
, 0,
405 (struct sockaddr
*)&peer
, sa_len(&peer
)) == -1 && errno
== EINTR
);
408 free_transfer(transfer
);
411 transfer
->next
= daemon
->tftp_trans
;
412 daemon
->tftp_trans
= transfer
;
416 static struct tftp_file
*check_tftp_fileperm(ssize_t
*len
, char *prefix
)
418 char *packet
= daemon
->packet
, *namebuff
= daemon
->namebuff
;
419 struct tftp_file
*file
;
420 struct tftp_transfer
*t
;
421 uid_t uid
= geteuid();
425 /* trick to ban moving out of the subtree */
426 if (prefix
&& strstr(namebuff
, "/../"))
429 if ((fd
= open(namebuff
, O_RDONLY
)) == -1)
433 *len
= tftp_err(ERR_FNF
, packet
, _("file %s not found"), namebuff
);
436 else if (errno
== EACCES
)
442 /* stat the file descriptor to avoid stat->open races */
443 if (fstat(fd
, &statbuf
) == -1)
446 /* running as root, must be world-readable */
449 if (!(statbuf
.st_mode
& S_IROTH
))
452 /* in secure mode, must be owned by user running dnsmasq */
453 else if (option_bool(OPT_TFTP_SECURE
) && uid
!= statbuf
.st_uid
)
456 /* If we're doing many tranfers from the same file, only
457 open it once this saves lots of file descriptors
458 when mass-booting a big cluster, for instance.
459 Be conservative and only share when inode and name match
460 this keeps error messages sane. */
461 for (t
= daemon
->tftp_trans
; t
; t
= t
->next
)
462 if (t
->file
->dev
== statbuf
.st_dev
&&
463 t
->file
->inode
== statbuf
.st_ino
&&
464 strcmp(t
->file
->filename
, namebuff
) == 0)
471 if (!(file
= whine_malloc(sizeof(struct tftp_file
) + strlen(namebuff
) + 1)))
478 file
->size
= statbuf
.st_size
;
479 file
->dev
= statbuf
.st_dev
;
480 file
->inode
= statbuf
.st_ino
;
482 strcpy(file
->filename
, namebuff
);
487 *len
= tftp_err(ERR_PERM
, packet
, _("cannot access %s: %s"), namebuff
);
493 *len
= tftp_err_oops(packet
, namebuff
);
499 void check_tftp_listeners(fd_set
*rset
, time_t now
)
501 struct tftp_transfer
*transfer
, *tmp
, **up
;
505 unsigned short op
, block
;
506 } *mess
= (struct ack
*)daemon
->packet
;
508 /* Check for activity on any existing transfers */
509 for (transfer
= daemon
->tftp_trans
, up
= &daemon
->tftp_trans
; transfer
; transfer
= tmp
)
511 tmp
= transfer
->next
;
513 prettyprint_addr(&transfer
->peer
, daemon
->addrbuff
);
515 if (FD_ISSET(transfer
->sockfd
, rset
))
517 /* we overwrote the buffer... */
518 daemon
->srv_save
= NULL
;
520 if ((len
= recv(transfer
->sockfd
, daemon
->packet
, daemon
->packet_buff_sz
, 0)) >= (ssize_t
)sizeof(struct ack
))
522 if (ntohs(mess
->op
) == OP_ACK
&& ntohs(mess
->block
) == (unsigned short)transfer
->block
)
524 /* Got ack, ensure we take the (re)transmit path */
525 transfer
->timeout
= now
;
526 transfer
->backoff
= 0;
527 if (transfer
->block
++ != 0)
528 transfer
->offset
+= transfer
->blocksize
- transfer
->expansion
;
530 else if (ntohs(mess
->op
) == OP_ERR
)
532 char *p
= daemon
->packet
+ sizeof(struct ack
);
533 char *end
= daemon
->packet
+ len
;
534 char *err
= next(&p
, end
);
536 /* Sanitise error message */
542 my_syslog(MS_TFTP
| LOG_ERR
, _("error %d %s received from %s"),
543 (int)ntohs(mess
->block
), err
,
546 /* Got err, ensure we take abort */
547 transfer
->timeout
= now
;
548 transfer
->backoff
= 100;
553 if (difftime(now
, transfer
->timeout
) >= 0.0)
557 /* timeout, retransmit */
558 transfer
->timeout
+= 1 + (1<<transfer
->backoff
);
560 /* we overwrote the buffer... */
561 daemon
->srv_save
= NULL
;
563 if ((len
= get_block(daemon
->packet
, transfer
)) == -1)
565 len
= tftp_err_oops(daemon
->packet
, transfer
->file
->filename
);
568 /* don't complain about timeout when we're awaiting the last
569 ACK, some clients never send it */
570 else if (++transfer
->backoff
> 7 && len
!= 0)
577 while(sendto(transfer
->sockfd
, daemon
->packet
, len
, 0,
578 (struct sockaddr
*)&transfer
->peer
, sa_len(&transfer
->peer
)) == -1 && errno
== EINTR
);
580 if (endcon
|| len
== 0)
582 strcpy(daemon
->namebuff
, transfer
->file
->filename
);
583 sanitise(daemon
->namebuff
);
584 my_syslog(MS_TFTP
| LOG_INFO
, endcon
? _("failed sending %s to %s") : _("sent %s to %s"), daemon
->namebuff
, daemon
->addrbuff
);
588 free_transfer(transfer
);
591 /* put on queue to be sent to script and deleted */
592 transfer
->next
= daemon
->tftp_done_trans
;
593 daemon
->tftp_done_trans
= transfer
;
599 up
= &transfer
->next
;
603 static void free_transfer(struct tftp_transfer
*transfer
)
605 close(transfer
->sockfd
);
606 if (transfer
->file
&& (--transfer
->file
->refcount
) == 0)
608 close(transfer
->file
->fd
);
609 free(transfer
->file
);
614 static char *next(char **p
, char *end
)
621 (len
= strlen(ret
)) == 0)
628 static void sanitise(char *buf
)
630 unsigned char *q
, *r
;
631 for (q
= r
= (unsigned char *)buf
; *r
; r
++)
632 if (isprint((int)*r
))
638 static ssize_t
tftp_err(int err
, char *packet
, char *message
, char *file
)
641 unsigned short op
, err
;
643 } *mess
= (struct errmess
*)packet
;
645 char *errstr
= strerror(errno
);
649 mess
->op
= htons(OP_ERR
);
650 mess
->err
= htons(err
);
651 ret
+= (snprintf(mess
->message
, 500, message
, file
, errstr
) + 1);
652 my_syslog(MS_TFTP
| LOG_ERR
, "%s", mess
->message
);
657 static ssize_t
tftp_err_oops(char *packet
, char *file
)
659 /* May have >1 refs to file, so potentially mangle a copy of the name */
660 strcpy(daemon
->namebuff
, file
);
661 return tftp_err(ERR_NOTDEF
, packet
, _("cannot read %s: %s"), daemon
->namebuff
);
664 /* return -1 for error, zero for done. */
665 static ssize_t
get_block(char *packet
, struct tftp_transfer
*transfer
)
667 if (transfer
->block
== 0)
674 } *mess
= (struct oackmess
*)packet
;
677 mess
->op
= htons(OP_OACK
);
678 if (transfer
->opt_blocksize
)
680 p
+= (sprintf(p
, "blksize") + 1);
681 p
+= (sprintf(p
, "%d", transfer
->blocksize
) + 1);
683 if (transfer
->opt_transize
)
685 p
+= (sprintf(p
,"tsize") + 1);
686 p
+= (sprintf(p
, "%u", (unsigned int)transfer
->file
->size
) + 1);
693 /* send data packet */
695 unsigned short op
, block
;
696 unsigned char data
[];
697 } *mess
= (struct datamess
*)packet
;
699 size_t size
= transfer
->file
->size
- transfer
->offset
;
701 if (transfer
->offset
> transfer
->file
->size
)
702 return 0; /* finished */
704 if (size
> transfer
->blocksize
)
705 size
= transfer
->blocksize
;
707 mess
->op
= htons(OP_DATA
);
708 mess
->block
= htons((unsigned short)(transfer
->block
));
710 if (lseek(transfer
->file
->fd
, transfer
->offset
, SEEK_SET
) == (off_t
)-1 ||
711 !read_write(transfer
->file
->fd
, mess
->data
, size
, 1))
714 transfer
->expansion
= 0;
716 /* Map '\n' to CR-LF in netascii mode */
717 if (transfer
->netascii
)
722 for (i
= 0, newcarrylf
= 0; i
< size
; i
++)
723 if (mess
->data
[i
] == '\n' && ( i
!= 0 || !transfer
->carrylf
))
725 transfer
->expansion
++;
727 if (size
!= transfer
->blocksize
)
728 size
++; /* room in this block */
729 else if (i
== size
- 1)
730 newcarrylf
= 1; /* don't expand LF again if it moves to the next block */
732 /* make space and insert CR */
733 memmove(&mess
->data
[i
+1], &mess
->data
[i
], size
- (i
+ 1));
734 mess
->data
[i
] = '\r';
738 transfer
->carrylf
= newcarrylf
;
747 int do_tftp_script_run(void)
749 struct tftp_transfer
*transfer
;
751 if ((transfer
= daemon
->tftp_done_trans
))
753 daemon
->tftp_done_trans
= transfer
->next
;
755 queue_tftp(transfer
->file
->size
, transfer
->file
->filename
, &transfer
->peer
);
757 free_transfer(transfer
);