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Diffstat (limited to 'networking')
-rw-r--r--networking/ftpd.c400
1 files changed, 154 insertions, 246 deletions
diff --git a/networking/ftpd.c b/networking/ftpd.c
index e83066032..2a7d8006b 100644
--- a/networking/ftpd.c
+++ b/networking/ftpd.c
@@ -63,9 +63,24 @@
#define STR1(s) #s
#define STR(s) STR1(s)
+/* Convert a constant to 3-digit string, packed into uint32_t */
enum {
- OPT_v = (1 << 0),
- OPT_w = (1 << 1),
+ /* Shift for Nth decimal digit */
+ SHIFT0 = 16 * BB_LITTLE_ENDIAN + 8 * BB_BIG_ENDIAN,
+ SHIFT1 = 8 * BB_LITTLE_ENDIAN + 16 * BB_BIG_ENDIAN,
+ SHIFT2 = 0 * BB_LITTLE_ENDIAN + 24 * BB_BIG_ENDIAN,
+};
+#define STRNUM32(s) (uint32_t)(0 \
+ | (('0' + ((s) / 1 % 10)) << SHIFT0) \
+ | (('0' + ((s) / 10 % 10)) << SHIFT1) \
+ | (('0' + ((s) / 100 % 10)) << SHIFT2) \
+)
+
+enum {
+ OPT_l = (1 << 0),
+ OPT_1 = (1 << 1),
+ OPT_v = (1 << 2),
+ OPT_w = (1 << 3),
#define mk_const4(a,b,c,d) (((a * 0x100 + b) * 0x100 + c) * 0x100 + d)
#define mk_const3(a,b,c) ((a * 0x100 + b) * 0x100 + c)
@@ -106,78 +121,84 @@ struct globals {
len_and_sockaddr *local_addr;
len_and_sockaddr *port_addr;
int pasv_listen_fd;
- int data_fd;
+ int proc_self_fd;
off_t restart_pos;
char *ftp_cmd;
char *ftp_arg;
#if ENABLE_FEATURE_FTP_WRITE
char *rnfr_filename;
#endif
- smallint opts;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)
static char *
-escape_text(const char *prepend, const char *str, char from, const char *to, char append)
+escape_text(const char *prepend, const char *str, unsigned escapee)
{
- size_t retlen, remainlen, chunklen, tolen;
- const char *remain;
+ unsigned retlen, remainlen, chunklen;
char *ret, *found;
+ char append;
- remain = str;
- remainlen = strlen(str);
- tolen = strlen(to);
+ append = (char)escapee;
+ escapee >>= 8;
- /* Simply alloc strlen(str)*strlen(to). "to" is max 2 so it's ok */
+ remainlen = strlen(str);
retlen = strlen(prepend);
- ret = xmalloc(retlen + remainlen * tolen + 1 + 1);
+ ret = xmalloc(retlen + remainlen * 2 + 1 + 1);
strcpy(ret, prepend);
for (;;) {
- found = strchrnul(remain, from);
- chunklen = found - remain;
+ found = strchrnul(str, escapee);
+ chunklen = found - str + 1;
- /* Copy chunk which doesn't contain 'from' to ret */
- memcpy(&ret[retlen], remain, chunklen);
+ /* Copy chunk up to and including escapee (or NUL) to ret */
+ memcpy(ret + retlen, str, chunklen);
retlen += chunklen;
- if (*found != '\0') {
- /* Now copy 'to' instead of 'from' */
- memcpy(&ret[retlen], to, tolen);
- retlen += tolen;
-
- remain = found + 1;
- } else {
- ret[retlen] = append;
- ret[retlen+1] = '\0';
+ if (*found == '\0') {
+ /* It wasn't escapee, it was NUL! */
+ ret[retlen - 1] = append; /* replace NUL */
+ ret[retlen] = '\0'; /* add NUL */
break;
}
+ ret[retlen++] = escapee; /* duplicate escapee */
+ str = found + 1;
}
return ret;
}
-static void
+/* Returns strlen as a bonus */
+static unsigned
replace_char(char *str, char from, char to)
{
- while ((str = strchr(str, from)) != NULL)
- *str++ = to;
+ char *p = str;
+ while (*p) {
+ if (*p == from)
+ *p = to;
+ p++;
+ }
+ return p - str;
}
static void
-cmdio_write(unsigned status, const char *str)
+cmdio_write(uint32_t status_str, const char *str)
{
+ union {
+ char buf[4];
+ uint32_t v32;
+ } u;
char *response;
int len;
+ u.v32 = status_str;
+
/* FTP allegedly uses telnet protocol for command link.
* In telnet, 0xff is an escape char, and needs to be escaped: */
- response = escape_text(utoa(status), str, '\xff', "\xff\xff", '\r');
+ response = escape_text(u.buf, str, (0xff << 8) + '\r');
/* ?! does FTP send embedded LFs as NULs? wow */
- len = strlen(response);
- replace_char(response, '\n', '\0');
+ len = replace_char(response, '\n', '\0');
response[len++] = '\n'; /* tack on trailing '\n' */
xwrite(STDOUT_FILENO, response, len);
@@ -215,9 +236,9 @@ handle_pwd(void)
cwd = xstrdup("");
/* We have to promote each " to "" */
- response = escape_text(" \"", cwd, '\"', "\"\"", '\"');
+ response = escape_text(" \"", cwd, ('"' << 8) + '"');
free(cwd);
- cmdio_write(FTP_PWDOK, response);
+ cmdio_write(STRNUM32(FTP_PWDOK), response);
free(response);
}
@@ -261,21 +282,6 @@ handle_help(void)
/* Download commands */
-static void
-init_data_sock_params(int sock_fd)
-{
- struct linger linger;
-
- G.data_fd = sock_fd;
-
- memset(&linger, 0, sizeof(linger));
- linger.l_onoff = 1;
- linger.l_linger = 32767;
-
- setsockopt(sock_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
- setsockopt(sock_fd, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
-}
-
static int
ftpdataio_get_pasv_fd(void)
{
@@ -288,39 +294,10 @@ ftpdataio_get_pasv_fd(void)
return remote_fd;
}
- init_data_sock_params(remote_fd);
- return remote_fd;
-}
-
-static int
-ftpdataio_get_port_fd(void)
-{
- int remote_fd;
-
- /* Do we want to die or print error to client? */
- remote_fd = xconnect_stream(G.port_addr);
-
- init_data_sock_params(remote_fd);
+ setsockopt(remote_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
return remote_fd;
}
-static void
-ftpdataio_dispose_transfer_fd(void)
-{
- /* This close() blocks because we set SO_LINGER */
- if (G.data_fd > STDOUT_FILENO) {
- if (close(G.data_fd) < 0) {
- /* Do it again without blocking. */
- struct linger linger;
-
- memset(&linger, 0, sizeof(linger));
- setsockopt(G.data_fd, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
- close(G.data_fd);
- }
- }
- G.data_fd = -1;
-}
-
static inline int
port_active(void)
{
@@ -341,12 +318,12 @@ get_remote_transfer_fd(const char *p_status_msg)
if (pasv_active())
remote_fd = ftpdataio_get_pasv_fd();
else
- remote_fd = ftpdataio_get_port_fd();
+ remote_fd = xconnect_stream(G.port_addr);
if (remote_fd < 0)
return remote_fd;
- cmdio_write(FTP_DATACONN, p_status_msg);
+ cmdio_write(STRNUM32(FTP_DATACONN), p_status_msg);
return remote_fd;
}
@@ -374,21 +351,21 @@ port_pasv_cleanup(void)
static unsigned
bind_for_passive_mode(void)
{
+ int fd;
unsigned port;
port_pasv_cleanup();
- G.pasv_listen_fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
- setsockopt_reuseaddr(G.pasv_listen_fd);
+ G.pasv_listen_fd = fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
+ setsockopt_reuseaddr(fd);
set_nport(G.local_addr, 0);
- xbind(G.pasv_listen_fd, &G.local_addr->u.sa, G.local_addr->len);
- xlisten(G.pasv_listen_fd, 1);
- getsockname(G.pasv_listen_fd, &G.local_addr->u.sa, &G.local_addr->len);
+ xbind(fd, &G.local_addr->u.sa, G.local_addr->len);
+ xlisten(fd, 1);
+ getsockname(fd, &G.local_addr->u.sa, &G.local_addr->len);
port = get_nport(&G.local_addr->u.sa);
port = ntohs(port);
-
return port;
}
@@ -487,7 +464,7 @@ handle_retr(void)
G.restart_pos = 0;
if (!data_transfer_checks_ok())
- return;
+ return; /* data_transfer_checks_ok emitted error response */
/* O_NONBLOCK is useful if file happens to be a device node */
opened_file = G.ftp_arg ? open(G.ftp_arg, O_RDONLY | O_NONBLOCK) : -1;
@@ -520,7 +497,7 @@ handle_retr(void)
goto port_pasv_cleanup_out;
trans_ret = bb_copyfd_eof(opened_file, remote_fd);
- ftpdataio_dispose_transfer_fd();
+ close(remote_fd);
if (trans_ret < 0)
cmdio_write_error(FTP_BADSENDFILE);
else
@@ -535,185 +512,105 @@ handle_retr(void)
/* List commands */
-static char *
-statbuf_getperms(const struct stat *statbuf)
-{
- char *perms;
- enum { r = 'r', w = 'w', x = 'x', s = 's', S = 'S' };
-
- perms = xmalloc(11);
- memset(perms, '-', 10);
-
- perms[0] = '?';
- switch (statbuf->st_mode & S_IFMT) {
- case S_IFREG: perms[0] = '-'; break;
- case S_IFDIR: perms[0] = 'd'; break;
- case S_IFLNK: perms[0] = 'l'; break;
- case S_IFIFO: perms[0] = 'p'; break;
- case S_IFSOCK: perms[0] = s; break;
- case S_IFCHR: perms[0] = 'c'; break;
- case S_IFBLK: perms[0] = 'b'; break;
- }
-
- if (statbuf->st_mode & S_IRUSR) perms[1] = r;
- if (statbuf->st_mode & S_IWUSR) perms[2] = w;
- if (statbuf->st_mode & S_IXUSR) perms[3] = x;
- if (statbuf->st_mode & S_IRGRP) perms[4] = r;
- if (statbuf->st_mode & S_IWGRP) perms[5] = w;
- if (statbuf->st_mode & S_IXGRP) perms[6] = x;
- if (statbuf->st_mode & S_IROTH) perms[7] = r;
- if (statbuf->st_mode & S_IWOTH) perms[8] = w;
- if (statbuf->st_mode & S_IXOTH) perms[9] = x;
- if (statbuf->st_mode & S_ISUID) perms[3] = (perms[3] == x) ? s : S;
- if (statbuf->st_mode & S_ISGID) perms[6] = (perms[6] == x) ? s : S;
- if (statbuf->st_mode & S_ISVTX) perms[9] = (perms[9] == x) ? 't' : 'T';
-
- perms[10] = '\0';
-
- return perms;
-}
-
-static void
-write_filestats(int fd, const char *filename,
- const struct stat *statbuf)
-{
- off_t size;
- char *stats, *lnkname = NULL, *perms;
- const char *name;
- char timestr[32];
- struct tm *tm;
-
- name = bb_get_last_path_component_nostrip(filename);
-
- if (statbuf != NULL) {
- size = statbuf->st_size;
-
- if (S_ISLNK(statbuf->st_mode))
- /* Damn symlink... */
- lnkname = xmalloc_readlink(filename);
-
- tm = gmtime(&statbuf->st_mtime);
- if (strftime(timestr, sizeof(timestr), "%b %d %H:%M", tm) == 0)
- bb_error_msg_and_die("strftime");
-
- timestr[sizeof(timestr) - 1] = '\0';
-
- perms = statbuf_getperms(statbuf);
-
- stats = xasprintf("%s %u\tftp ftp %"OFF_FMT"u\t%s %s",
- perms, (int) statbuf->st_nlink,
- size, timestr, name);
-
- free(perms);
- } else
- stats = xstrdup(name);
-
- xwrite_str(fd, stats);
- free(stats);
- if (lnkname != NULL) {
- xwrite_str(fd, " -> ");
- xwrite_str(fd, lnkname);
- free(lnkname);
- }
- xwrite_str(fd, "\r\n");
-}
-
-static void
-write_dirstats(int fd, const char *dname, int details)
+static int
+popen_ls(const char *opt)
{
- DIR *dir;
- struct dirent *dirent;
- struct stat statbuf;
- char *filename;
-
- dir = xopendir(dname);
+ char *cwd;
+ const char *argv[5] = { "ftpd", opt, NULL, G.ftp_arg, NULL };
+ struct fd_pair outfd;
+ pid_t pid;
- for (;;) {
- dirent = readdir(dir);
- if (dirent == NULL)
- break;
+ cwd = xrealloc_getcwd_or_warn(NULL);
- /* Ignore . and .. */
- if (dirent->d_name[0] == '.') {
- if (dirent->d_name[1] == '\0'
- || (dirent->d_name[1] == '.' && dirent->d_name[2] == '\0')
- ) {
- continue;
- }
+ xpiped_pair(outfd);
+
+ fflush(NULL);
+ pid = vfork();
+
+ switch (pid) {
+ case -1: /* failure */
+ bb_perror_msg_and_die("vfork");
+ case 0: /* child */
+ /* NB: close _first_, then move fds! */
+ close(outfd.rd);
+ xmove_fd(outfd.wr, STDOUT_FILENO);
+ close(STDIN_FILENO);
+ /* xopen("/dev/null", O_RDONLY); - chroot may lack it! */
+ if (fchdir(G.proc_self_fd) == 0) {
+ close(G.proc_self_fd);
+ argv[2] = cwd;
+ /* ftpd ls helper chdirs to argv[2],
+ * preventing peer from seeing /proc/self
+ */
+ execv("exe", (char**) argv);
}
-
- if (details) {
- filename = xasprintf("%s/%s", dname, dirent->d_name);
- if (lstat(filename, &statbuf) != 0) {
- free(filename);
- break;
- }
- } else
- filename = xstrdup(dirent->d_name);
-
- write_filestats(fd, filename, details ? &statbuf : NULL);
- free(filename);
+ _exit(127);
}
-
- closedir(dir);
+ /* parent */
+ close(outfd.wr);
+ free(cwd);
+ return outfd.rd;
}
static void
-handle_dir_common(int full_details, int stat_cmd)
+handle_dir_common(int opts)
{
- int fd;
- struct stat statbuf;
+ FILE *ls_fp;
+ char *line;
+ int ls_fd;
- if (!stat_cmd && !data_transfer_checks_ok())
- return;
+ if (!(opts & 1) && !data_transfer_checks_ok())
+ return; /* data_transfer_checks_ok emitted error response */
+
+ ls_fd = popen_ls((opts & 2) ? "-l" : "-1");
+ ls_fp = fdopen(ls_fd, "r");
+ if (!ls_fp) /* never happens. paranoia */
+ bb_perror_msg_and_die("fdopen");
- if (stat_cmd) {
- fd = STDIN_FILENO;
+ if (opts & 1) {
+ /* STAT <filename> */
cmdio_write_raw(STR(FTP_STATFILE_OK)"-Status follows:\r\n");
+ while (1) {
+ line = xmalloc_fgetline(ls_fp);
+ if (!line)
+ break;
+ cmdio_write(0, line); /* hack: 0 results in no status at all */
+ free(line);
+ }
+ cmdio_write_ok(FTP_STATFILE_OK);
} else {
- fd = get_remote_transfer_fd(" Here comes the directory listing");
- if (fd < 0)
- goto bail;
- }
-
- if (G.ftp_arg) {
- if (lstat(G.ftp_arg, &statbuf) != 0) {
- /* Dir doesn't exist => return ok to client */
- goto bail;
+ /* LIST/NLST [<filename>] */
+ int remote_fd = get_remote_transfer_fd(" Here comes the directory listing");
+ if (remote_fd >= 0) {
+ while (1) {
+ line = xmalloc_fgetline(ls_fp);
+ if (!line)
+ break;
+ xwrite_str(remote_fd, line);
+ xwrite(remote_fd, "\r\n", 2);
+ free(line);
+ }
}
- if (S_ISREG(statbuf.st_mode) || S_ISLNK(statbuf.st_mode))
- write_filestats(fd, G.ftp_arg, &statbuf);
- else if (S_ISDIR(statbuf.st_mode))
- write_dirstats(fd, G.ftp_arg, full_details);
- } else
- write_dirstats(fd, ".", full_details);
-
- bail:
- /* Well, if we can't open directory/file it doesn't matter */
- if (!stat_cmd) {
- ftpdataio_dispose_transfer_fd();
+ close(remote_fd);
port_pasv_cleanup();
cmdio_write_ok(FTP_TRANSFEROK);
- } else
- cmdio_write_ok(FTP_STATFILE_OK);
+ }
+ fclose(ls_fp); /* closes ls_fd too */
}
-
static void
handle_list(void)
{
- handle_dir_common(1, 0);
+ handle_dir_common(2);
}
-
static void
handle_nlst(void)
{
- handle_dir_common(0, 0);
+ handle_dir_common(0);
}
-
static void
handle_stat_file(void)
{
- handle_dir_common(1, 1);
+ handle_dir_common(3);
}
static void
@@ -840,7 +737,7 @@ handle_upload_common(int is_append, int is_unique)
goto bail;
trans_ret = bb_copyfd_eof(remote_fd, local_file_fd);
- ftpdataio_dispose_transfer_fd();
+ close(remote_fd);
if (trans_ret < 0)
cmdio_write_error(FTP_BADSENDFILE);
@@ -905,8 +802,19 @@ cmdio_get_cmd_and_arg(void)
}
int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int ftpd_main(int argc UNUSED_PARAM, char **argv)
+int ftpd_main(int argc, char **argv)
{
+ smallint opts;
+
+ opts = getopt32(argv, "l1v" USE_FEATURE_FTP_WRITE("w"));
+
+ if (opts & (OPT_l|OPT_1)) {
+ /* Our secret backdoor to ls */
+ xchdir(argv[2]);
+ argv[2] = (char*)"--";
+ return ls_main(argc, argv);
+ }
+
INIT_G();
G.local_addr = get_sock_lsa(STDIN_FILENO);
@@ -920,13 +828,13 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
* failure */
}
- G.opts = getopt32(argv, "v" USE_FEATURE_FTP_WRITE("w"));
-
openlog(applet_name, LOG_PID, LOG_DAEMON);
logmode |= LOGMODE_SYSLOG;
- if (!(G.opts & OPT_v))
+ if (!(opts & OPT_v))
logmode = LOGMODE_SYSLOG;
+ G.proc_self_fd = xopen("/proc/self", O_RDONLY | O_DIRECTORY);
+
if (argv[optind]) {
xchdir(argv[optind]);
chroot(".");
@@ -1064,7 +972,7 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
else if (cmdval == const_REST)
handle_rest();
#if ENABLE_FEATURE_FTP_WRITE
- else if (G.opts & OPT_w) {
+ else if (opts & OPT_w) {
if (cmdval == const_STOR)
handle_stor();
else if (cmdval == const_MKD)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 08:41:29 +0000