httpd: fix handling of range requests
[oweals/busybox.git] / networking / tftp.c
index 9a9bd2c34d8ec291135a9221aeebad2da20d768e..ed86720257aab7b62ba39ed9f218aa6724040741 100644 (file)
  *
  * tftpd added by Denys Vlasenko & Vladimir Dronnikov
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+//config:config TFTP
+//config:      bool "tftp"
+//config:      default y
+//config:      help
+//config:        This enables the Trivial File Transfer Protocol client program. TFTP
+//config:        is usually used for simple, small transfers such as a root image
+//config:        for a network-enabled bootloader.
+//config:
+//config:config TFTPD
+//config:      bool "tftpd"
+//config:      default y
+//config:      help
+//config:        This enables the Trivial File Transfer Protocol server program.
+//config:        It expects that stdin is a datagram socket and a packet
+//config:        is already pending on it. It will exit after one transfer.
+//config:        In other words: it should be run from inetd in nowait mode,
+//config:        or from udpsvd. Example: "udpsvd -E 0 69 tftpd DIR"
+//config:
+//config:comment "Common options for tftp/tftpd"
+//config:      depends on TFTP || TFTPD
+//config:
+//config:config FEATURE_TFTP_GET
+//config:      bool "Enable 'tftp get' and/or tftpd upload code"
+//config:      default y
+//config:      depends on TFTP || TFTPD
+//config:      help
+//config:        Add support for the GET command within the TFTP client. This allows
+//config:        a client to retrieve a file from a TFTP server.
+//config:        Also enable upload support in tftpd, if tftpd is selected.
+//config:
+//config:        Note: this option does _not_ make tftpd capable of download
+//config:        (the usual operation people need from it)!
+//config:
+//config:config FEATURE_TFTP_PUT
+//config:      bool "Enable 'tftp put' and/or tftpd download code"
+//config:      default y
+//config:      depends on TFTP || TFTPD
+//config:      help
+//config:        Add support for the PUT command within the TFTP client. This allows
+//config:        a client to transfer a file to a TFTP server.
+//config:        Also enable download support in tftpd, if tftpd is selected.
+//config:
+//config:config FEATURE_TFTP_BLOCKSIZE
+//config:      bool "Enable 'blksize' and 'tsize' protocol options"
+//config:      default y
+//config:      depends on TFTP || TFTPD
+//config:      help
+//config:        Allow tftp to specify block size, and tftpd to understand
+//config:        "blksize" and "tsize" options.
+//config:
+//config:config FEATURE_TFTP_PROGRESS_BAR
+//config:      bool "Enable tftp progress meter"
+//config:      default y
+//config:      depends on TFTP && FEATURE_TFTP_BLOCKSIZE
+//config:      help
+//config:        Show progress bar.
+//config:
+//config:config TFTP_DEBUG
+//config:      bool "Enable debug"
+//config:      default n
+//config:      depends on TFTP || TFTPD
+//config:      help
+//config:        Make tftp[d] print debugging messages on stderr.
+//config:        This is useful if you are diagnosing a bug in tftp[d].
+
+//applet:#if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT
+//applet:IF_TFTP(APPLET(tftp, BB_DIR_USR_BIN, BB_SUID_DROP))
+//applet:IF_TFTPD(APPLET(tftpd, BB_DIR_USR_SBIN, BB_SUID_DROP))
+//applet:#endif
+
+//kbuild:lib-$(CONFIG_TFTP) += tftp.o
+//kbuild:lib-$(CONFIG_TFTPD) += tftp.o
+
+//usage:#define tftp_trivial_usage
+//usage:       "[OPTIONS] HOST [PORT]"
+//usage:#define tftp_full_usage "\n\n"
+//usage:       "Transfer a file from/to tftp server\n"
+//usage:     "\n       -l FILE Local FILE"
+//usage:     "\n       -r FILE Remote FILE"
+//usage:       IF_FEATURE_TFTP_GET(
+//usage:     "\n       -g      Get file"
+//usage:       )
+//usage:       IF_FEATURE_TFTP_PUT(
+//usage:     "\n       -p      Put file"
+//usage:       )
+//usage:       IF_FEATURE_TFTP_BLOCKSIZE(
+//usage:     "\n       -b SIZE Transfer blocks of SIZE octets"
+//usage:       )
+//usage:
+//usage:#define tftpd_trivial_usage
+//usage:       "[-cr] [-u USER] [DIR]"
+//usage:#define tftpd_full_usage "\n\n"
+//usage:       "Transfer a file on tftp client's request\n"
+//usage:       "\n"
+//usage:       "tftpd should be used as an inetd service.\n"
+//usage:       "tftpd's line for inetd.conf:\n"
+//usage:       "       69 dgram udp nowait root tftpd tftpd -l /files/to/serve\n"
+//usage:       "It also can be ran from udpsvd:\n"
+//usage:       "       udpsvd -vE 0.0.0.0 69 tftpd /files/to/serve\n"
+//usage:     "\n       -r      Prohibit upload"
+//usage:     "\n       -c      Allow file creation via upload"
+//usage:     "\n       -u      Access files as USER"
+//usage:     "\n       -l      Log to syslog (inetd mode requires this)"
+
 #include "libbb.h"
+#include "common_bufsiz.h"
+#include <syslog.h>
 
 #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT
 
 #define TFTP_BLKSIZE_DEFAULT       512  /* according to RFC 1350, don't change */
 #define TFTP_BLKSIZE_DEFAULT_STR "512"
-#define TFTP_TIMEOUT_MS             50
+/* Was 50 ms but users asked to bump it up a bit */
+#define TFTP_TIMEOUT_MS            100
 #define TFTP_MAXTIMEOUT_MS        2000
 #define TFTP_NUM_RETRIES            12  /* number of backed-off retries */
 
@@ -58,6 +165,7 @@ enum {
        TFTPD_OPT_r = (1 << 8) * ENABLE_TFTPD,
        TFTPD_OPT_c = (1 << 9) * ENABLE_TFTPD,
        TFTPD_OPT_u = (1 << 10) * ENABLE_TFTPD,
+       TFTPD_OPT_l = (1 << 11) * ENABLE_TFTPD,
 };
 
 #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT
@@ -81,66 +189,48 @@ enum {
 struct globals {
        /* u16 TFTP_ERROR; u16 reason; both network-endian, then error text: */
        uint8_t error_pkt[4 + 32];
-       char *user_opt;
-       /* used in tftpd_main(), a bit big for stack: */
-       char block_buf[TFTP_BLKSIZE_DEFAULT];
+       struct passwd *pw;
+       /* Used in tftpd_main() for initial packet */
+       /* Some HP PA-RISC firmware always sends fixed 516-byte requests */
+       char block_buf[516];
+       char block_buf_tail[1];
 #if ENABLE_FEATURE_TFTP_PROGRESS_BAR
        off_t pos;
        off_t size;
        const char *file;
        bb_progress_t pmt;
 #endif
-};
-#define G (*(struct globals*)&bb_common_bufsiz1)
-struct BUG_G_too_big {
-       char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
-};
-#define block_buf        (G.block_buf   )
-#define user_opt         (G.user_opt    )
-#define error_pkt        (G.error_pkt   )
-#define INIT_G() do { } while (0)
+} FIX_ALIASING;
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() do { \
+       setup_common_bufsiz(); \
+       BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
+} while (0)
 
-#define error_pkt_reason (error_pkt[3])
-#define error_pkt_str    (error_pkt + 4)
+#define G_error_pkt_reason (G.error_pkt[3])
+#define G_error_pkt_str    ((char*)(G.error_pkt + 4))
 
 #if ENABLE_FEATURE_TFTP_PROGRESS_BAR
-/* SIGALRM logic nicked from the wget applet */
-static void progress_meter(int flag)
+static void tftp_progress_update(void)
 {
-       /* We can be called from signal handler */
-       int save_errno = errno;
-
-       if (flag == -1) { /* first call to progress_meter */
-               bb_progress_init(&G.pmt);
-       }
-
-       bb_progress_update(&G.pmt, G.file, 0, G.pos, G.size);
-
-       if (flag == 0) {
-               /* last call to progress_meter */
-               alarm(0);
-               fputc('\n', stderr);
-       } else {
-               if (flag == -1) { /* first call to progress_meter */
-                       signal_SA_RESTART_empty_mask(SIGALRM, progress_meter);
-               }
-               alarm(1);
-       }
-
-       errno = save_errno;
+       bb_progress_update(&G.pmt, 0, G.pos, G.size);
 }
-static void tftp_progress_init(const char *file)
+static void tftp_progress_init(void)
 {
-       G.file = file;
-       progress_meter(-1);
+       bb_progress_init(&G.pmt, G.file);
+       tftp_progress_update();
 }
 static void tftp_progress_done(void)
 {
-       progress_meter(0);
+       if (is_bb_progress_inited(&G.pmt)) {
+               tftp_progress_update();
+               bb_putchar_stderr('\n');
+               bb_progress_free(&G.pmt);
+       }
 }
 #else
-# define tftp_progress_init(file) ((void)0)
-# define tftp_progress_done()     ((void)0)
+# define tftp_progress_init() ((void)0)
+# define tftp_progress_done() ((void)0)
 #endif
 
 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
@@ -254,12 +344,11 @@ static int tftp_protocol(
                xconnect(socket_fd, &peer_lsa->u.sa, peer_lsa->len);
 
                /* Is there an error already? Send pkt and bail out */
-               if (error_pkt_reason || error_pkt_str[0])
+               if (G_error_pkt_reason || G_error_pkt_str[0])
                        goto send_err_pkt;
 
-               if (user_opt) {
-                       struct passwd *pw = xgetpwnam(user_opt);
-                       change_identity(pw); /* initgroups, setgid, setuid */
+               if (G.pw) {
+                       change_identity(G.pw); /* initgroups, setgid, setuid */
                }
        }
 
@@ -309,10 +398,10 @@ static int tftp_protocol(
 
        if (!ENABLE_TFTP || our_lsa) { /* tftpd */
                /* Open file (must be after changing user) */
-               local_fd = open(local_file, open_mode);
+               local_fd = open(local_file, open_mode, 0666);
                if (local_fd < 0) {
-                       error_pkt_reason = ERR_NOFILE;
-                       strcpy((char*)error_pkt_str, "can't open file");
+                       G_error_pkt_reason = ERR_NOFILE;
+                       strcpy(G_error_pkt_str, "can't open file");
                        goto send_err_pkt;
                }
 /* gcc 4.3.1 would NOT optimize it out as it should! */
@@ -332,7 +421,6 @@ static int tftp_protocol(
                         * as if it is "block 0" */
                        block_nr = 0;
                }
-
        } else { /* tftp */
                /* Open file (must be after changing user) */
                local_fd = CMD_GET(option_mask32) ? STDOUT_FILENO : STDIN_FILENO;
@@ -411,7 +499,7 @@ static int tftp_protocol(
                         * we look at server's reply later */
                        G.size = st.st_size;
                        if (remote_file && st.st_size)
-                               tftp_progress_init(remote_file);
+                               tftp_progress_init();
 # endif
                }
 #endif
@@ -438,6 +526,7 @@ static int tftp_protocol(
                                finished = 1;
                        }
                        cp += len;
+                       IF_FEATURE_TFTP_PROGRESS_BAR(G.pos += len;)
                }
  send_pkt:
                /* Send packet */
@@ -446,7 +535,7 @@ static int tftp_protocol(
                /* NB: send_len value is preserved in code below
                 * for potential resend */
 
-               retries = TFTP_NUM_RETRIES;     /* re-initialize */
+               retries = TFTP_NUM_RETRIES;  /* re-initialize */
                waittime_ms = TFTP_TIMEOUT_MS;
 
  send_again:
@@ -459,9 +548,8 @@ static int tftp_protocol(
                xsendto(socket_fd, xbuf, send_len, &peer_lsa->u.sa, peer_lsa->len);
 
 #if ENABLE_FEATURE_TFTP_PROGRESS_BAR
-               if (ENABLE_TFTP && remote_file) { /* tftp */
-                       G.pos = (block_nr - 1) * (uoff_t)blksize;
-               }
+               if (is_bb_progress_inited(&G.pmt))
+                       tftp_progress_update();
 #endif
                /* Was it final ACK? then exit */
                if (finished && (opcode == TFTP_ACK))
@@ -478,6 +566,7 @@ static int tftp_protocol(
                case 0:
                        retries--;
                        if (retries == 0) {
+                               tftp_progress_done();
                                bb_error_msg("timeout");
                                goto ret; /* no err packet sent */
                        }
@@ -556,18 +645,18 @@ static int tftp_protocol(
                                if (res) {
                                        blksize = tftp_blksize_check(res, blksize);
                                        if (blksize < 0) {
-                                               error_pkt_reason = ERR_BAD_OPT;
+                                               G_error_pkt_reason = ERR_BAD_OPT;
                                                goto send_err_pkt;
                                        }
                                        io_bufsize = blksize + 4;
                                }
 # if ENABLE_FEATURE_TFTP_PROGRESS_BAR
-                               if (G.size == 0) { /* if we don't know it yet */
+                               if (remote_file && G.size == 0) { /* if we don't know it yet */
                                        res = tftp_get_option("tsize", &rbuf[2], len - 2);
                                        if (res) {
                                                G.size = bb_strtoull(res, NULL, 10);
-                                               if (remote_file && G.size)
-                                                       tftp_progress_init(remote_file);
+                                               if (G.size)
+                                                       tftp_progress_init();
                                        }
                                }
 # endif
@@ -580,9 +669,10 @@ static int tftp_protocol(
                        }
                        /* rfc2347:
                         * "An option not acknowledged by the server
-                        *  must be ignored by the client and server
-                        *  as if it were never requested." */
-                       bb_error_msg("server only supports blocksize of 512");
+                        * must be ignored by the client and server
+                        * as if it were never requested." */
+                       if (blksize != TFTP_BLKSIZE_DEFAULT)
+                               bb_error_msg("falling back to blocksize "TFTP_BLKSIZE_DEFAULT_STR);
                        blksize = TFTP_BLKSIZE_DEFAULT;
                        io_bufsize = TFTP_BLKSIZE_DEFAULT + 4;
                }
@@ -594,13 +684,14 @@ static int tftp_protocol(
                        if (recv_blk == block_nr) {
                                int sz = full_write(local_fd, &rbuf[4], len - 4);
                                if (sz != len - 4) {
-                                       strcpy((char*)error_pkt_str, bb_msg_write_error);
-                                       error_pkt_reason = ERR_WRITE;
+                                       strcpy(G_error_pkt_str, bb_msg_write_error);
+                                       G_error_pkt_reason = ERR_WRITE;
                                        goto send_err_pkt;
                                }
                                if (sz != blksize) {
                                        finished = 1;
                                }
+                               IF_FEATURE_TFTP_PROGRESS_BAR(G.pos += sz;)
                                continue; /* send ACK */
                        }
 /* Disabled to cope with servers with Sorcerer's Apprentice Syndrome */
@@ -643,12 +734,12 @@ static int tftp_protocol(
        return finished == 0; /* returns 1 on failure */
 
  send_read_err_pkt:
-       strcpy((char*)error_pkt_str, bb_msg_read_error);
+       strcpy(G_error_pkt_str, bb_msg_read_error);
  send_err_pkt:
-       if (error_pkt_str[0])
-               bb_error_msg("%s", (char*)error_pkt_str);
-       error_pkt[1] = TFTP_ERROR;
-       xsendto(socket_fd, error_pkt, 4 + 1 + strlen((char*)error_pkt_str),
+       if (G_error_pkt_str[0])
+               bb_error_msg("%s", G_error_pkt_str);
+       G.error_pkt[1] = TFTP_ERROR;
+       xsendto(socket_fd, G.error_pkt, 4 + 1 + strlen(G_error_pkt_str),
                        &peer_lsa->u.sa, peer_lsa->len);
        return EXIT_FAILURE;
 #undef remote_file
@@ -715,6 +806,9 @@ int tftp_main(int argc UNUSED_PARAM, char **argv)
                        remote_file, local_file);
 # endif
 
+# if ENABLE_FEATURE_TFTP_PROGRESS_BAR
+       G.file = remote_file;
+# endif
        result = tftp_protocol(
                NULL /*our_lsa*/, peer_lsa,
                local_file, remote_file
@@ -737,7 +831,8 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
 {
        len_and_sockaddr *our_lsa;
        len_and_sockaddr *peer_lsa;
-       char *local_file, *mode;
+       char *mode, *user_opt;
+       char *local_file = local_file;
        const char *error_msg;
        int opt, result, opcode;
        IF_FEATURE_TFTP_BLOCKSIZE(int blksize = TFTP_BLKSIZE_DEFAULT;)
@@ -759,19 +854,30 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
        peer_lsa->len = our_lsa->len;
 
        /* Shifting to not collide with TFTP_OPTs */
-       opt = option_mask32 = TFTPD_OPT | (getopt32(argv, "rcu:", &user_opt) << 8);
+       opt = option_mask32 = TFTPD_OPT | (getopt32(argv, "rcu:l", &user_opt) << 8);
        argv += optind;
-       if (argv[0])
-               xchdir(argv[0]);
+       if (opt & TFTPD_OPT_l) {
+               openlog(applet_name, LOG_PID, LOG_DAEMON);
+               logmode = LOGMODE_SYSLOG;
+       }
+       if (opt & TFTPD_OPT_u) {
+               /* Must be before xchroot */
+               G.pw = xgetpwnam(user_opt);
+       }
+       if (argv[0]) {
+               xchroot(argv[0]);
+       }
 
-       result = recv_from_to(STDIN_FILENO, block_buf, sizeof(block_buf),
+       result = recv_from_to(STDIN_FILENO,
+                       G.block_buf, sizeof(G.block_buf) + 1,
+                       /* ^^^ sizeof+1 to reliably detect oversized input */
                        0 /* flags */,
                        &peer_lsa->u.sa, &our_lsa->u.sa, our_lsa->len);
 
        error_msg = "malformed packet";
-       opcode = ntohs(*(uint16_t*)block_buf);
-       if (result < 4 || result >= sizeof(block_buf)
-        || block_buf[result-1] != '\0'
+       opcode = ntohs(*(uint16_t*)G.block_buf);
+       if (result < 4 || result > sizeof(G.block_buf)
+       /*|| G.block_buf[result-1] != '\0' - bug compatibility, see below */
         || (IF_FEATURE_TFTP_PUT(opcode != TFTP_RRQ) /* not download */
             IF_GETPUT(&&)
             IF_FEATURE_TFTP_GET(opcode != TFTP_WRQ) /* not upload */
@@ -779,32 +885,42 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
        ) {
                goto err;
        }
-       local_file = block_buf + 2;
+       /* Some HP PA-RISC firmware always sends fixed 516-byte requests,
+        * with trailing garbage.
+        * Support that by not requiring NUL to be the last byte (see above).
+        * To make strXYZ() ops safe, force NUL termination:
+        */
+       G.block_buf_tail[0] = '\0';
+
+       local_file = G.block_buf + 2;
        if (local_file[0] == '.' || strstr(local_file, "/.")) {
                error_msg = "dot in file name";
                goto err;
        }
        mode = local_file + strlen(local_file) + 1;
-       if (mode >= block_buf + result || strcmp(mode, "octet") != 0) {
+       /* RFC 1350 says mode string is case independent */
+       if (mode >= G.block_buf + result || strcasecmp(mode, "octet") != 0) {
                goto err;
        }
 # if ENABLE_FEATURE_TFTP_BLOCKSIZE
        {
                char *res;
                char *opt_str = mode + sizeof("octet");
-               int opt_len = block_buf + result - opt_str;
+               int opt_len = G.block_buf + result - opt_str;
                if (opt_len > 0) {
                        res = tftp_get_option("blksize", opt_str, opt_len);
                        if (res) {
                                blksize = tftp_blksize_check(res, 65564);
                                if (blksize < 0) {
-                                       error_pkt_reason = ERR_BAD_OPT;
+                                       G_error_pkt_reason = ERR_BAD_OPT;
                                        /* will just send error pkt */
                                        goto do_proto;
                                }
                        }
+                       if (opcode != TFTP_WRQ /* download? */
                        /* did client ask us about file size? */
-                       if (tftp_get_option("tsize", opt_str, opt_len)) {
+                        && tftp_get_option("tsize", opt_str, opt_len)
+                       ) {
                                want_transfer_size = 1;
                        }
                }
@@ -814,17 +930,16 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
        if (!ENABLE_FEATURE_TFTP_PUT || opcode == TFTP_WRQ) {
                if (opt & TFTPD_OPT_r) {
                        /* This would mean "disk full" - not true */
-                       /*error_pkt_reason = ERR_WRITE;*/
+                       /*G_error_pkt_reason = ERR_WRITE;*/
                        error_msg = bb_msg_write_error;
                        goto err;
                }
                IF_GETPUT(option_mask32 |= TFTP_OPT_GET;) /* will receive file's data */
-               want_transfer_size = 0; /* do not send file size, it's meaningless */
        } else {
                IF_GETPUT(option_mask32 |= TFTP_OPT_PUT;) /* will send file's data */
        }
 
-       /* NB: if error_pkt_str or error_pkt_reason is set up,
+       /* NB: if G_error_pkt_str or G_error_pkt_reason is set up,
         * tftp_protocol() just sends one error pkt and returns */
 
  do_proto:
@@ -839,7 +954,7 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
 
        return result;
  err:
-       strcpy((char*)error_pkt_str, error_msg);
+       strcpy(G_error_pkt_str, error_msg);
        goto do_proto;
 }