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Diffstat (limited to 'networking/tftp.c')
-rw-r--r--networking/tftp.c334
1 files changed, 242 insertions, 92 deletions
diff --git a/networking/tftp.c b/networking/tftp.c
index 1872615..23a2413 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -2,7 +2,7 @@
/* -------------------------------------------------------------------------
* tftp.c
*
- * A simple tftp client for busybox.
+ * A simple tftp client/server for busybox.
* Tries to follow RFC1350.
* Only "octet" mode supported.
* Optional blocksize negotiation (RFC2347 + RFC2348)
@@ -16,6 +16,8 @@
*
* utftp: Copyright (C) 1999 Uwe Ohse <uwe@ohse.de>
*
+ * tftpd added by Denys Vlasenko
+ *
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
* ------------------------------------------------------------------------- */
@@ -46,7 +48,7 @@
#define CMD_PUT(cmd) 1
#else
#define USE_GETPUT(...) __VA_ARGS__
-/* masks coming from getpot32 */
+/* masks coming from getopt32 */
#define CMD_GET(cmd) ((cmd) & 1)
#define CMD_PUT(cmd) ((cmd) & 2)
#endif
@@ -64,14 +66,12 @@ static int tftp_blocksize_check(int blocksize, int bufsize)
* but our implementation makes it impossible
* to use blocksizes smaller than 22 octets.
*/
-
if ((bufsize && (blocksize > bufsize))
- || (blocksize < 8) || (blocksize > 65564)
+ || (blocksize < 24) || (blocksize > 65564)
) {
bb_error_msg("bad blocksize");
return 0;
}
-
return blocksize;
}
@@ -81,8 +81,11 @@ static char *tftp_option_get(char *buf, int len, const char *option)
int opt_found = 0;
int k;
+ /* buf points to:
+ * "opt_name<NUL>opt_val<NUL>opt_name2<NUL>opt_val2<NUL>..." */
+
while (len > 0) {
- /* Make sure the options are terminated correctly */
+ /* Make sure options are terminated correctly */
for (k = 0; k < len; k++) {
if (buf[k] == '\0') {
goto nul_found;
@@ -90,7 +93,7 @@ static char *tftp_option_get(char *buf, int len, const char *option)
}
return NULL;
nul_found:
- if (opt_val == 0) {
+ if (opt_val == 0) { /* it's "name" part */
if (strcasecmp(buf, option) == 0) {
opt_found = 1;
}
@@ -109,77 +112,116 @@ static char *tftp_option_get(char *buf, int len, const char *option)
#endif
-static int tftp( USE_GETPUT(const int cmd,)
+static int tftp_protocol(
+ USE_GETPUT(int cmd,)
+ len_and_sockaddr *our_lsa,
len_and_sockaddr *peer_lsa,
- const char *remotefile, const int localfd,
- unsigned port, int tftp_bufsize)
+ USE_TFTP(const char *remote_file,)
+ int local_fd,
+ int blocksize)
{
+#if !ENABLE_TFTP
+#define remote_file NULL
+#endif
struct pollfd pfd[1];
-#define socketfd (pfd[0].fd)
+#define socket_fd (pfd[0].fd)
int len;
int send_len;
USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
smallint finished = 0;
uint16_t opcode;
- uint16_t block_nr = 1;
+ uint16_t block_nr;
uint16_t recv_blk;
int retries, waittime_ms;
+ int tftp_bufsize = blocksize + 4;
char *cp;
-
- unsigned org_port;
- len_and_sockaddr *const from = alloca(LSA_LEN_SIZE + peer_lsa->len);
-
/* Can't use RESERVE_CONFIG_BUFFER here since the allocation
* size varies meaning BUFFERS_GO_ON_STACK would fail */
/* We must keep the transmit and receive buffers seperate */
/* In case we rcv a garbage pkt and we need to rexmit the last pkt */
- char *xbuf = xmalloc(tftp_bufsize += 4);
+ char *xbuf = xmalloc(tftp_bufsize);
char *rbuf = xmalloc(tftp_bufsize);
- port = org_port = htons(port);
+ socket_fd = xsocket(peer_lsa->u.sa.sa_family, SOCK_DGRAM, 0);
+ setsockopt_reuseaddr(socket_fd);
- socketfd = xsocket(peer_lsa->u.sa.sa_family, SOCK_DGRAM, 0);
+ if (!ENABLE_TFTP || our_lsa) {
+ /* tftpd */
+ block_nr = 0;
- /* build opcode */
- opcode = TFTP_WRQ;
- if (CMD_GET(cmd)) {
- opcode = TFTP_RRQ;
- }
- cp = xbuf + 2;
- /* add filename and mode */
- /* fill in packet if the filename fits into xbuf */
- len = strlen(remotefile) + 1;
- if (2 + len + sizeof("octet") >= tftp_bufsize) {
- bb_error_msg("remote filename is too long");
- goto ret;
- }
- strcpy(cp, remotefile);
- cp += len;
- /* add "mode" part of the package */
- strcpy(cp, "octet");
- cp += sizeof("octet");
+ /* Create a socket which is:
+ * 1. bound to IP:port peer sent 1st datagram to,
+ * 2. connected to peer's IP:port
+ * This way we will answer from the IP:port peer
+ * expects, will not get any other packets on
+ * the socket, and also plain read/write will work. */
+ xbind(socket_fd, &our_lsa->u.sa, our_lsa->len);
+ xconnect(socket_fd, &peer_lsa->u.sa, peer_lsa->len);
#if ENABLE_FEATURE_TFTP_BLOCKSIZE
- len = tftp_bufsize - 4; /* data block size */
- if (len != TFTP_BLOCKSIZE_DEFAULT) {
- /* rfc2348 says that 65464 is a max allowed value */
- if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) {
+ if (blocksize != TFTP_BLOCKSIZE_DEFAULT) {
+ /* Create and send OACK packet */
+ opcode = TFTP_OACK;
+ cp = xbuf + 2;
+ goto add_blksize_opt;
+ }
+ /* else: just fall into while (1) loop below */
+#endif
+ } else {
+ /* tftp */
+ block_nr = 1;
+
+ /* We can't (and don't really need to) bind the socket:
+ * we don't know from which local IP datagrams will be sent,
+ * but kernel will pick the same IP every time (unless routing
+ * table is changed), thus peer will see dgrams consistently
+ * coming from the same IP.
+ * We would like to connect the socket, but since peer's
+ * UDP code can be less perfect than ours, _peer's_ IP:port
+ * in replies may differ from IP:port we used to send
+ * our first packet. We can connect() only when we get
+ * first reply. */
+
+ /* build opcode */
+ opcode = TFTP_WRQ;
+ if (CMD_GET(cmd)) {
+ opcode = TFTP_RRQ;
+ }
+ cp = xbuf + 2;
+ /* add filename and mode */
+ /* fill in packet if the filename fits into xbuf */
+ len = strlen(remote_file) + 1;
+ if (2 + len + sizeof("octet") >= tftp_bufsize) {
bb_error_msg("remote filename is too long");
goto ret;
}
- /* add "blksize", <nul>, blocksize */
- strcpy(cp, "blksize");
- cp += sizeof("blksize");
- cp += snprintf(cp, 6, "%d", len) + 1;
- want_option_ack = 1;
- }
+ strcpy(cp, remote_file);
+ cp += len;
+ /* add "mode" part of the package */
+ strcpy(cp, "octet");
+ cp += sizeof("octet");
+
+#if ENABLE_FEATURE_TFTP_BLOCKSIZE
+ if (blocksize != TFTP_BLOCKSIZE_DEFAULT) {
+ /* rfc2348 says that 65464 is a max allowed value */
+ if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) {
+ bb_error_msg("remote filename is too long");
+ goto ret;
+ }
+ want_option_ack = 1;
+ add_blksize_opt:
+ /* add "blksize", <nul>, blocksize, <nul> */
+ strcpy(cp, "blksize");
+ cp += sizeof("blksize");
+ cp += snprintf(cp, 6, "%d", blocksize) + 1;
+ }
#endif
- /* First packet is built, so skip packet generation */
- goto send_pkt;
+ /* First packet is built, so skip packet generation */
+ goto send_pkt;
+ }
/* Using mostly goto's - continue/break will be less clear
* in where we actually jump to */
-
while (1) {
/* Build ACK or DATA */
cp = xbuf + 2;
@@ -189,7 +231,7 @@ static int tftp( USE_GETPUT(const int cmd,)
opcode = TFTP_ACK;
if (CMD_PUT(cmd)) {
opcode = TFTP_DATA;
- len = full_read(localfd, cp, tftp_bufsize - 4);
+ len = full_read(local_fd, cp, tftp_bufsize - 4);
if (len < 0) {
bb_perror_msg(bb_msg_read_error);
goto ret;
@@ -216,36 +258,36 @@ static int tftp( USE_GETPUT(const int cmd,)
fprintf(stderr, "%02x ", (unsigned char) *cp);
fprintf(stderr, "\n");
#endif
- xsendto(socketfd, xbuf, send_len, &peer_lsa->u.sa, peer_lsa->len);
+ xsendto(socket_fd, xbuf, send_len, &peer_lsa->u.sa, peer_lsa->len);
/* Was it final ACK? then exit */
if (finished && (opcode == TFTP_ACK))
goto ret;
recv_again:
/* Receive packet */
- /*pfd[0].fd = socketfd;*/
+ /*pfd[0].fd = socket_fd;*/
pfd[0].events = POLLIN;
switch (safe_poll(pfd, 1, waittime_ms)) {
- unsigned from_port;
case 1:
- from->len = peer_lsa->len;
- memset(&from->u.sa, 0, peer_lsa->len);
- len = recvfrom(socketfd, rbuf, tftp_bufsize, 0,
- &from->u.sa, &from->len);
+ if (!our_lsa) {
+ /* tftp (not tftpd!) receiving 1st packet */
+ our_lsa = ((void*)(ptrdiff_t)-1); /* not NULL */
+ len = recvfrom(socket_fd, rbuf, tftp_bufsize, 0,
+ &peer_lsa->u.sa, &peer_lsa->len);
+ /* Our first dgram went to port 69
+ * but reply may come from different one.
+ * Remember and use this new port (and IP) */
+ if (len >= 0)
+ xconnect(socket_fd, &peer_lsa->u.sa, peer_lsa->len);
+ } else {
+ /* tftpd, or not the very first packet:
+ * socket is connect()ed, can just read from it. */
+ len = safe_read(socket_fd, rbuf, tftp_bufsize);
+ }
if (len < 0) {
- bb_perror_msg("recvfrom");
+ bb_perror_msg("read");
goto ret;
}
- from_port = get_nport(&from->u.sa);
- if (port == org_port) {
- /* Our first query went to port 69
- * but reply will come from different one.
- * Remember and use this new port */
- port = from_port;
- set_nport(peer_lsa, from_port);
- }
- if (port != from_port)
- goto recv_again;
goto process_pkt;
case 0:
retries--;
@@ -316,7 +358,7 @@ static int tftp( USE_GETPUT(const int cmd,)
/*static const uint16_t error_8[2] = { htons(TFTP_ERROR), htons(8) };*/
/* thus we open-code big-endian layout */
static const uint8_t error_8[4] = { 0,TFTP_ERROR, 0,8 };
- xsendto(socketfd, error_8, 4, &peer_lsa->u.sa, peer_lsa->len);
+ xsendto(socket_fd, error_8, 4, &peer_lsa->u.sa, peer_lsa->len);
bb_error_msg("server proposes bad blksize %d, exiting", blksize);
goto ret;
}
@@ -345,7 +387,7 @@ static int tftp( USE_GETPUT(const int cmd,)
if (CMD_GET(cmd) && (opcode == TFTP_DATA)) {
if (recv_blk == block_nr) {
- len = full_write(localfd, &rbuf[4], len - 4);
+ len = full_write(local_fd, &rbuf[4], len - 4);
if (len < 0) {
bb_perror_msg(bb_msg_write_error);
goto ret;
@@ -363,7 +405,7 @@ static int tftp( USE_GETPUT(const int cmd,)
}
if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) {
- /* did server ACK our last DATA pkt? */
+ /* did peer ACK our last DATA pkt? */
if (recv_blk == (uint16_t) (block_nr - 1)) {
if (finished)
goto ret;
@@ -381,25 +423,27 @@ static int tftp( USE_GETPUT(const int cmd,)
* See:
* http://en.wikipedia.org/wiki/Sorcerer's_Apprentice_Syndrome
*/
- }
+ } /* end of "while (1)" */
ret:
if (ENABLE_FEATURE_CLEAN_UP) {
- close(socketfd);
+ close(socket_fd);
free(xbuf);
free(rbuf);
}
return finished == 0; /* returns 1 on failure */
}
+#if ENABLE_TFTP
+
int tftp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tftp_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
len_and_sockaddr *peer_lsa;
- const char *localfile = NULL;
- const char *remotefile = NULL;
+ const char *local_file = NULL;
+ const char *remote_file = NULL;
int port;
USE_GETPUT(int cmd;)
- int fd = -1;
+ int local_fd;
int flags = 0;
int result;
int blocksize = TFTP_BLOCKSIZE_DEFAULT;
@@ -412,7 +456,7 @@ int tftp_main(int argc ATTRIBUTE_UNUSED, char **argv)
USE_GETPUT(cmd =) getopt32(argv,
USE_FEATURE_TFTP_GET("g") USE_FEATURE_TFTP_PUT("p")
"l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"),
- &localfile, &remotefile
+ &local_file, &remote_file
USE_FEATURE_TFTP_BLOCKSIZE(, &blocksize));
argv += optind;
@@ -425,36 +469,142 @@ int tftp_main(int argc ATTRIBUTE_UNUSED, char **argv)
return EXIT_FAILURE;
#endif
- if (!localfile)
- localfile = remotefile;
- if (!remotefile)
- remotefile = localfile;
+ if (!local_file)
+ local_file = remote_file;
+ if (!remote_file)
+ remote_file = local_file;
/* Error if filename or host is not known */
- if (!remotefile || !argv[0])
+ if (!remote_file || !argv[0])
bb_show_usage();
- fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
- if (!LONE_DASH(localfile)) {
- fd = xopen(localfile, flags);
+ local_fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
+ if (!LONE_DASH(local_file)) {
+ local_fd = xopen(local_file, flags);
}
port = bb_lookup_port(argv[1], "udp", 69);
peer_lsa = xhost2sockaddr(argv[0], port);
#if ENABLE_DEBUG_TFTP
- fprintf(stderr, "using server '%s', remotefile '%s', localfile '%s'\n",
+ fprintf(stderr, "using server '%s', remote_file '%s', local_file '%s'\n",
xmalloc_sockaddr2dotted(&peer_lsa->u.sa),
- remotefile, localfile);
+ remote_file, local_file);
#endif
- result = tftp( USE_GETPUT(cmd,) peer_lsa, remotefile, fd, port, blocksize);
+ result = tftp_protocol(
+ USE_GETPUT(cmd,)
+ NULL /* our_lsa*/,
+ peer_lsa,
+ remote_file, local_fd, blocksize);
if (ENABLE_FEATURE_CLEAN_UP)
- close(fd);
- if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) {
- unlink(localfile);
+ close(local_fd);
+ if (result != EXIT_SUCCESS && !LONE_DASH(local_file) && CMD_GET(cmd)) {
+ unlink(local_file);
}
return result;
}
+#endif /* ENABLE_TFTP */
+
+#if ENABLE_TFTPD
+
+/* TODO: libbb candidate? */
+static len_and_sockaddr *get_sock_lsa(int s)
+{
+ len_and_sockaddr *lsa;
+ socklen_t len = 0;
+
+ if (getsockname(s, NULL, &len) != 0)
+ return NULL;
+ lsa = xzalloc(LSA_LEN_SIZE + len);
+ lsa->len = len;
+ getsockname(s, &lsa->u.sa, &lsa->len);
+ return lsa;
+}
+
+int tftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int tftpd_main(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
+{
+ struct stat statbuf;
+ char block_buf[TFTP_BLOCKSIZE_DEFAULT];
+ len_and_sockaddr *our_lsa;
+ len_and_sockaddr *peer_lsa;
+ char *filename, *mode, *opt_str;
+ int result, opcode, cmd, req_modebits, open_mode, local_fd, blksize;
+
+ our_lsa = get_sock_lsa(STDIN_FILENO);
+ if (!our_lsa)
+ bb_perror_msg_and_die("stdin is not a socket");
+ peer_lsa = xzalloc(LSA_LEN_SIZE + our_lsa->len);
+ peer_lsa->len = our_lsa->len;
+
+ if (argv[1])
+ xchdir(argv[1]);
+
+ result = recv_from_to(STDIN_FILENO, block_buf, sizeof(block_buf),
+ 0 /* flags */,
+ &peer_lsa->u.sa, &our_lsa->u.sa, our_lsa->len);
+
+ opcode = ntohs(*(uint16_t*)block_buf);
+ if (result < 4 || result >= sizeof(block_buf)
+ || block_buf[result-1] != '\0'
+ || (opcode != TFTP_RRQ && opcode != TFTP_WRQ)
+ ) {
+ bb_error_msg_and_die("malformed packet");
+ }
+ filename = block_buf + 2;
+ if (filename[0] == '.' || strstr(filename, "/.")) {
+ bb_error_msg_and_die("dot in filename");
+ }
+ mode = filename + strlen(filename) + 1;
+ if (mode >= block_buf + sizeof(block_buf)
+ || strcmp(mode, "octet") != 0
+ ) {
+ bb_error_msg_and_die("malformed packet");
+ }
+ blksize = TFTP_BLOCKSIZE_DEFAULT;
+#if ENABLE_FEATURE_TFTP_BLOCKSIZE
+ opt_str = mode + 6;
+ if (opt_str < block_buf + sizeof(block_buf)) {
+ char *res = tftp_option_get(opt_str, block_buf + sizeof(block_buf) - opt_str, "blksize");
+ if (res) {
+ int sz = xatoi_u(res);
+ if (tftp_blocksize_check(sz, 0))
+ blksize = sz;
+ }
+ }
+#endif
+ xstat(filename, &statbuf);
+ /* if opcode == TFTP_WRQ: */
+ cmd = 1; /* CMD_GET: we will receive file's data */
+ req_modebits = 0222; /* writable by anyone */
+ open_mode = O_WRONLY | O_TRUNC;
+ if (opcode == TFTP_RRQ) {
+ cmd = 2; /* CMD_PUT */
+ req_modebits = 0444; /* readable by anyone */
+ open_mode = O_RDONLY;
+ }
+ if (!S_ISREG(statbuf.st_mode)
+ || (statbuf.st_mode & req_modebits) != req_modebits
+ ) {
+ bb_error_msg_and_die("access to '%s' is denied", filename);
+ }
+ local_fd = xopen(filename, open_mode);
+
+ close(STDIN_FILENO); /* close old, possibly wildcard socket */
+ /* tftp_protocol() will create new one, bound to particular local IP */
+ result = tftp_protocol(
+ USE_GETPUT(cmd,)
+ our_lsa, peer_lsa,
+ USE_TFTP(NULL /*remote_file*/,)
+ local_fd,
+ blksize
+ );
+
+ return result;
+}
+
+#endif /* ENABLE_TFTPD */
+
#endif /* ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT */
generated by cgit v1.1 at 2024-12-29 09:28:59 +0000