http://blog.chinaunix.net/uid-25082381-id-3242162.html
2013-01-06 13:54
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http://blog.chinaunix.net/uid-25082381-id-3242162.html
因为项目用到了ftp传输文件的功能，设备要做ftp服务器，正好busybox有ftpd这个功能，所以就直接使用啦，但是测试发现，自带的这个ftpd登陆根本就不需要用户名和密码，所以这就有安全隐患了，这是不允许滴，搜索资料表明，搜不到关于ftpd用户名和密码登陆的问题，都是使用另外一个工具，lftp，于是我就编译了一个lftp，测试可以使用，但是因为编译的时候总是不过，需要屏蔽掉一些功能才可以编译通过，所以总觉得有隐患，于是决定再次研究一下ftpd为什么不能用户名和密码登陆，网上既然查不到，那只好自己去研究源代码啦，看到了ftpd的源代码文件ftpd.c里面有一个IF_WE_WANT_TO_REQUIRE_LOGIN，就是用来配置是否需要用户名和密码登陆的，可是这个宏却不能在busybox的make
xconfig中配置，所以我猜想肯定是因为这个功能还不完善，所以才不能配置的，于是自己在代码中打开试一下，编译通过，测试显示失败，于是查找代码发现，if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)，该if判断只要是匿名用户就可以登陆，而且后续没有对密码的验证，既然这样，那就只好自己实现啦，我的busybox的版本是1.17.2，一下是我的代码，里面所有在//wsm add和//end wsm之间的代码都是我添加的，你们可以和官方的未修改版进行对比就知道区别啦，代码如下，主要函数和代码我已经做了注释。
/* vi: set sw=4 ts=4: */
/*
* Simple FTP daemon, based on vsftpd 2.0.7 (written by Chris Evans)
*
* Author: Adam Tkac <vonsch@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*
* Only subset of FTP protocol is implemented but vast majority of clients
* should not have any problem.
*
* You have to run this daemon via inetd.
*/
#include "libbb.h"
#include <syslog.h>
#include <netinet/tcp.h>
//wsm add
#include <unistd.h>
#include <stdio.h>
#include <netinet/in.h>
#include <pwd.h>
#include <stdlib.h>
#include <crypt.h>
#include <string.h>
#include <shadow.h>
#define IF_WE_WANT_TO_REQUIRE_LOGIN
//end wsm
#define FTP_DATACONN 150
#define FTP_NOOPOK 200
#define FTP_TYPEOK 200
#define FTP_PORTOK 200
#define FTP_STRUOK 200
#define FTP_MODEOK 200
#define FTP_ALLOOK 202
#define FTP_STATOK 211
#define FTP_STATFILE_OK 213
#define FTP_HELP 214
#define FTP_SYSTOK 215
#define FTP_GREET 220
#define FTP_GOODBYE 221
#define FTP_TRANSFEROK 226
#define FTP_PASVOK 227
/*#define FTP_EPRTOK 228*/
#define FTP_EPSVOK 229
#define FTP_LOGINOK 230
#define FTP_CWDOK 250
#define FTP_RMDIROK 250
#define FTP_DELEOK 250
#define FTP_RENAMEOK 250
#define FTP_PWDOK 257
#define FTP_MKDIROK 257
#define FTP_GIVEPWORD 331
#define FTP_RESTOK 350
#define FTP_RNFROK 350
#define FTP_TIMEOUT 421
#define FTP_BADSENDCONN 425
#define FTP_BADSENDNET 426
#define FTP_BADSENDFILE 451
#define FTP_BADCMD 500
#define FTP_COMMANDNOTIMPL 502
#define FTP_NEEDUSER 503
#define FTP_NEEDRNFR 503
#define FTP_BADSTRU 504
#define FTP_BADMODE 504
#define FTP_LOGINERR 530
#define FTP_FILEFAIL 550
#define FTP_NOPERM 550
#define FTP_UPLOADFAIL 553
#define STR1(s) #s
#define STR(s) STR1(s)
/* Convert a constant to 3-digit string, packed into uint32_t */
enum {
/* Shift for Nth decimal digit */
SHIFT2 = 0 * BB_LITTLE_ENDIAN 24 * BB_BIG_ENDIAN,
SHIFT1 = 8 * BB_LITTLE_ENDIAN 16 * BB_BIG_ENDIAN,
SHIFT0 = 16 * BB_LITTLE_ENDIAN 8 * BB_BIG_ENDIAN,
/* And for 4th position (space) */
SHIFTsp = 24 * BB_LITTLE_ENDIAN 0 * BB_BIG_ENDIAN,
};
#define STRNUM32(s) (uint32_t)(0 \
| (('0' ((s) / 1 % 10)) << SHIFT0) \
| (('0' ((s) / 10 % 10)) << SHIFT1) \
| (('0' ((s) / 100 % 10)) << SHIFT2) \
)
#define STRNUM32sp(s) (uint32_t)(0 \
| (' ' << SHIFTsp) \
| (('0' ((s) / 1 % 10)) << SHIFT0) \
| (('0' ((s) / 10 % 10)) << SHIFT1) \
| (('0' ((s) / 100 % 10)) << SHIFT2) \
)
#define MSG_OK "Operation successful\r\n"
#define MSG_ERR "Error\r\n"
struct globals {
int pasv_listen_fd;
#if !BB_MMU
int root_fd;
#endif
int local_file_fd;
unsigned end_time;
unsigned timeout;
unsigned verbose;
off_t local_file_pos;
off_t restart_pos;
len_and_sockaddr *local_addr;
len_and_sockaddr *port_addr;
char *ftp_cmd;
char *ftp_arg;
#if ENABLE_FEATURE_FTP_WRITE
char *rnfr_filename;
#endif
/* We need these aligned to uint32_t */
char msg_ok [(sizeof("NNN " MSG_OK ) 3) & 0xfffc];
char msg_err[(sizeof("NNN " MSG_ERR) 3) & 0xfffc];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
/* Moved to main */ \
/*strcpy(G.msg_ok 4, MSG_OK );*/ \
/*strcpy(G.msg_err 4, MSG_ERR);*/ \
} while (0)
static char *
escape_text(const char *prepend, const char *str, unsigned escapee)
{
unsigned retlen, remainlen, chunklen;
char *ret, *found;
char append;
append = (char)escapee;
escapee >>= 8;
remainlen = strlen(str);
retlen = strlen(prepend);
ret = xmalloc(retlen remainlen * 2 1 1);
strcpy(ret, prepend);
for (;;) {
found = strchrnul(str, escapee);
chunklen = found - str 1;
/* Copy chunk up to and including escapee (or NUL) to ret */
memcpy(ret retlen, str, chunklen);
retlen = chunklen;
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;
}
/* Returns strlen as a bonus */
static unsigned
replace_char(char *str, char from, char to)
{
char *p = str;
while (*p) {
if (*p == from)
*p = to;
p ;
}
return p - str;
}
static void
verbose_log(const char *str)
{
bb_error_msg("%.*s", (int)strcspn(str, "\r\n"), str);
}
/* NB: status_str is char[4] packed into uint32_t */
static void
cmdio_write(uint32_t status_str, const char *str)
{
char *response;
int len;
/* FTP uses telnet protocol for command link.
* In telnet, 0xff is an escape char, and needs to be escaped: */
response = escape_text((char *) &status_str, str, (0xff << 8) '\r');
/* FTP sends embedded LFs as NULs */
len = replace_char(response, '\n', '\0');
response[len ] = '\n'; /* tack on trailing '\n' */
xwrite(STDOUT_FILENO, response, len);
if (G.verbose > 1)
verbose_log(response);
free(response);
}
static void
cmdio_write_ok(unsigned status)
{
*(uint32_t *) G.msg_ok = status;
xwrite(STDOUT_FILENO, G.msg_ok, sizeof("NNN " MSG_OK) - 1);
if (G.verbose > 1)
verbose_log(G.msg_ok);
}
#define WRITE_OK(a) cmdio_write_ok(STRNUM32sp(a))
/* TODO: output strerr(errno) if errno != 0? */
static void
cmdio_write_error(unsigned status)
{
*(uint32_t *) G.msg_err = status;
xwrite(STDOUT_FILENO, G.msg_err, sizeof("NNN " MSG_ERR) - 1);
if (G.verbose > 1)
verbose_log(G.msg_err);
}
#define WRITE_ERR(a) cmdio_write_error(STRNUM32sp(a))
static void
cmdio_write_raw(const char *p_text)
{
xwrite_str(STDOUT_FILENO, p_text);
if (G.verbose > 1)
verbose_log(p_text);
}
static void
timeout_handler(int sig UNUSED_PARAM)
{
off_t pos;
int sv_errno = errno;
if ((int)(monotonic_sec() - G.end_time) >= 0)
goto timed_out;
if (!G.local_file_fd)
goto timed_out;
pos = xlseek(G.local_file_fd, 0, SEEK_CUR);
if (pos == G.local_file_pos)
goto timed_out;
G.local_file_pos = pos;
alarm(G.timeout);
errno = sv_errno;
return;
timed_out:
cmdio_write_raw(STR(FTP_TIMEOUT)" Timeout\r\n");
/* TODO: do we need to abort (as opposed to usual shutdown) data transfer? */
exit(1);
}
/* Simple commands */
static void
handle_pwd(void)
{
char *cwd, *response;
cwd = xrealloc_getcwd_or_warn(NULL);
if (cwd == NULL)
cwd = xstrdup("");
/* We have to promote each " to "" */
response = escape_text(" \"", cwd, ('"' << 8) '"');
free(cwd);
cmdio_write(STRNUM32(FTP_PWDOK), response);
free(response);
}
static void
handle_cwd(void)
{
if (!G.ftp_arg || chdir(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_CWDOK);
}
static void
handle_cdup(void)
{
G.ftp_arg = (char*)"..";
handle_cwd();
}
static void
handle_stat(void)
{
cmdio_write_raw(STR(FTP_STATOK)"-Server status:\r\n"
" TYPE: BINARY\r\n"
STR(FTP_STATOK)" Ok\r\n");
}
/* Examples of HELP and FEAT:
# nc -vvv ftp.kernel.org 21
ftp.kernel.org (130.239.17.4:21) open
220 Welcome to ftp.kernel.org.
FEAT
211-Features:
EPRT
EPSV
MDTM
PASV
REST STREAM
SIZE
TVFS
UTF8
211 End
HELP
214-The following commands are recognized.
ABOR ACCT ALLO APPE CDUP CWD DELE EPRT EPSV FEAT HELP LIST MDTM MKD
MODE NLST NOOP OPTS PASS PASV PORT PWD QUIT REIN REST RETR RMD RNFR
RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
XPWD XRMD
214 Help OK.
*/
static void
handle_feat(unsigned status)
{
cmdio_write(status, "-Features:");
cmdio_write_raw(" EPSV\r\n"
" PASV\r\n"
" REST STREAM\r\n"
" MDTM\r\n"
" SIZE\r\n");
cmdio_write(status, " Ok");
}
/* Download commands */
static inline int
port_active(void)
{
return (G.port_addr != NULL);
}
static inline int
pasv_active(void)
{
return (G.pasv_listen_fd > STDOUT_FILENO);
}
static void
port_pasv_cleanup(void)
{
free(G.port_addr);
G.port_addr = NULL;
if (G.pasv_listen_fd > STDOUT_FILENO)
close(G.pasv_listen_fd);
G.pasv_listen_fd = -1;
}
/* On error, emits error code to the peer */
static int
ftpdataio_get_pasv_fd(void)
{
int remote_fd;
remote_fd = accept(G.pasv_listen_fd, NULL, 0);
if (remote_fd < 0) {
WRITE_ERR(FTP_BADSENDCONN);
return remote_fd;
}
setsockopt(remote_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
return remote_fd;
}
/* Clears port/pasv data.
* This means we dont waste resources, for example, keeping
* PASV listening socket open when it is no longer needed.
* On error, emits error code to the peer (or exits).
* On success, emits p_status_msg to the peer.
*/
static int
get_remote_transfer_fd(const char *p_status_msg)
{
int remote_fd;
if (pasv_active())
/* On error, emits error code to the peer */
remote_fd = ftpdataio_get_pasv_fd();
else
/* Exits on error */
remote_fd = xconnect_stream(G.port_addr);
port_pasv_cleanup();
if (remote_fd < 0)
return remote_fd;
cmdio_write(STRNUM32(FTP_DATACONN), p_status_msg);
return remote_fd;
}
/* If there were neither PASV nor PORT, emits error code to the peer */
static int
port_or_pasv_was_seen(void)
{
if (!pasv_active() && !port_active()) {
cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT/PASV first\r\n");
return 0;
}
return 1;
}
/* Exits on error */
static unsigned
bind_for_passive_mode(void)
{
int fd;
unsigned port;
port_pasv_cleanup();
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(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;
}
/* Exits on error */
static void
handle_pasv(void)
{
unsigned port;
char *addr, *response;
port = bind_for_passive_mode();
if (G.local_addr->u.sa.sa_family == AF_INET)
addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
else /* seen this in the wild done by other ftp servers: */
addr = xstrdup("0.0.0.0");
replace_char(addr, '.', ',');
response = xasprintf(STR(FTP_PASVOK)" PASV ok (%s,%u,%u)\r\n",
addr, (int)(port >> 8), (int)(port & 255));
free(addr);
cmdio_write_raw(response);
free(response);
}
/* Exits on error */
static void
handle_epsv(void)
{
unsigned port;
char *response;
port = bind_for_passive_mode();
response = xasprintf(STR(FTP_EPSVOK)" EPSV ok (|||%u|)\r\n", port);
cmdio_write_raw(response);
free(response);
}
static void
handle_port(void)
{
unsigned port, port_hi;
char *raw, *comma;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
socklen_t peer_ipv4_len;
struct sockaddr_in peer_ipv4;
struct in_addr port_ipv4_sin_addr;
#endif
port_pasv_cleanup();
raw = G.ftp_arg;
/* PORT command format makes sense only over IPv4 */
if (!raw
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
|| G.local_addr->u.sa.sa_family != AF_INET
#endif
) {
bail:
WRITE_ERR(FTP_BADCMD);
return;
}
comma = strrchr(raw, ',');
if (comma == NULL)
goto bail;
*comma = '\0';
port = bb_strtou(&comma[1], NULL, 10);
if (errno || port > 0xff)
goto bail;
comma = strrchr(raw, ',');
if (comma == NULL)
goto bail;
*comma = '\0';
port_hi = bb_strtou(&comma[1], NULL, 10);
if (errno || port_hi > 0xff)
goto bail;
port |= port_hi << 8;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
replace_char(raw, ',', '.');
/* We are verifying that PORT's IP matches getpeername().
* Otherwise peer can make us open data connections
* to other hosts (security problem!)
* This code would be too simplistic:
* lsa = xdotted2sockaddr(raw, port);
* if (lsa == NULL) goto bail;
*/
if (!inet_aton(raw, &port_ipv4_sin_addr))
goto bail;
peer_ipv4_len = sizeof(peer_ipv4);
if (getpeername(STDIN_FILENO, &peer_ipv4, &peer_ipv4_len) != 0)
goto bail;
if (memcmp(&port_ipv4_sin_addr, &peer_ipv4.sin_addr, sizeof(struct in_addr)) != 0)
goto bail;
G.port_addr = xdotted2sockaddr(raw, port);
#else
G.port_addr = get_peer_lsa(STDIN_FILENO);
set_nport(G.port_addr, htons(port));
#endif
WRITE_OK(FTP_PORTOK);
}
static void
handle_rest(void)
{
/* When ftp_arg == NULL simply restart from beginning */
G.restart_pos = G.ftp_arg ? xatoi_u(G.ftp_arg) : 0;
WRITE_OK(FTP_RESTOK);
}
static void
handle_retr(void)
{
struct stat statbuf;
off_t bytes_transferred;
int remote_fd;
int local_file_fd;
off_t offset = G.restart_pos;
char *response;
G.restart_pos = 0;
if (!port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
/* O_NONBLOCK is useful if file happens to be a device node */
local_file_fd = G.ftp_arg ? open(G.ftp_arg, O_RDONLY | O_NONBLOCK) : -1;
if (local_file_fd < 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
if (fstat(local_file_fd, &statbuf) != 0 || !S_ISREG(statbuf.st_mode)) {
/* Note - pretend open failed */
WRITE_ERR(FTP_FILEFAIL);
goto file_close_out;
}
G.local_file_fd = local_file_fd;
/* Now deactive O_NONBLOCK, otherwise we have a problem
* on DMAPI filesystems such as XFS DMAPI.
*/
ndelay_off(local_file_fd);
/* Set the download offset (from REST) if any */
if (offset != 0)
xlseek(local_file_fd, offset, SEEK_SET);
response = xasprintf(
" Opening BINARY connection for %s (%"OFF_FMT"u bytes)",
G.ftp_arg, statbuf.st_size);
remote_fd = get_remote_transfer_fd(response);
free(response);
if (remote_fd < 0)
goto file_close_out;
bytes_transferred = bb_copyfd_eof(local_file_fd, remote_fd);
close(remote_fd);
if (bytes_transferred < 0)
WRITE_ERR(FTP_BADSENDFILE);
else
WRITE_OK(FTP_TRANSFEROK);
file_close_out:
close(local_file_fd);
G.local_file_fd = 0;
}
/* List commands */
static int
popen_ls(const char *opt)
{
const char *argv[5];
struct fd_pair outfd;
pid_t pid;
argv[0] = "ftpd";
argv[1] = opt; /* "-l" or "-1" */
#if BB_MMU
argv[2] = "--";
#else
/* NOMMU ftpd ls helper chdirs to argv[2],
* preventing peer from seeing real root. */
argv[2] = xrealloc_getcwd_or_warn(NULL);
#endif
argv[3] = G.ftp_arg;
argv[4] = NULL;
/* Improve compatibility with non-RFC conforming FTP clients
* which send e.g. "LIST -l", "LIST -la", "LIST -aL".
* See https://bugs.kde.org/show_bug.cgi?id=195578 */
if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST
&& G.ftp_arg && G.ftp_arg[0] == '-'
) {
const char *tmp = strchr(G.ftp_arg, ' ');
if (tmp) /* skip the space */
tmp ;
argv[3] = tmp;
}
xpiped_pair(outfd);
/*fflush_all(); - so far we dont use stdio on output */
pid = BB_MMU ? xfork() : xvfork();
if (pid == 0) {
/* child */
#if !BB_MMU
/* On NOMMU, we want to execute a child - copy of ourself.
* In chroot we usually can't do it. Thus we chdir
* out of the chroot back to original root,
* and (see later below) execute bb_busybox_exec_path
* relative to current directory */
if (fchdir(G.root_fd) != 0)
_exit(127);
/*close(G.root_fd); - close_on_exec_on() took care of this */
#endif
/* NB: close _first_, then move fd! */
close(outfd.rd);
xmove_fd(outfd.wr, STDOUT_FILENO);
/* Opening /dev/null in chroot is hard.
* Just making sure STDIN_FILENO is opened
* to something harmless. Paranoia,
* ls won't read it anyway */
close(STDIN_FILENO);
dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
#if BB_MMU
/* memset(&G, 0, sizeof(G)); - ls_main does it */
exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
#else
/* 1: we must use relative path here if in chroot.
* For example, execv("/proc/self/exe") will fail, since
* it looks for "/proc/self/exe" _relative to chroot!_ */
execv(bb_busybox_exec_path 1, (char**) argv);
_exit(127);
#endif
}
/* parent */
close(outfd.wr);
#if !BB_MMU
free((char*)argv[2]);
#endif
return outfd.rd;
}
enum {
USE_CTRL_CONN = 1,
LONG_LISTING = 2,
};
static void
handle_dir_common(int opts)
{
FILE *ls_fp;
char *line;
int ls_fd;
if (!(opts & USE_CTRL_CONN) && !port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
/* -n prevents user/groupname display,
* which can be problematic in chroot */
ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1");
ls_fp = xfdopen_for_read(ls_fd);
if (opts & USE_CTRL_CONN) {
/* STAT <filename> */
cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n");
while (1) {
line = xmalloc_fgetline(ls_fp);
if (!line)
break;
/* Hack: 0 results in no status at all */
/* Note: it's ok that we don't prepend space,
* ftp.kernel.org doesn't do that too */
cmdio_write(0, line);
free(line);
}
WRITE_OK(FTP_STATFILE_OK);
} else {
/* LIST/NLST [<filename>] */
int remote_fd = get_remote_transfer_fd(" Directory listing");
if (remote_fd >= 0) {
while (1) {
line = xmalloc_fgetline(ls_fp);
if (!line)
break;
/* I've seen clients complaining when they
* are fed with ls output with bare '\n'.
* Pity... that would be much simpler.
*/
/* TODO: need to s/LF/NUL/g here */
xwrite_str(remote_fd, line);
xwrite(remote_fd, "\r\n", 2);
free(line);
}
}
close(remote_fd);
WRITE_OK(FTP_TRANSFEROK);
}
fclose(ls_fp); /* closes ls_fd too */
}
static void
handle_list(void)
{
handle_dir_common(LONG_LISTING);
}
static void
handle_nlst(void)
{
/* NLST returns list of names, "\r\n" terminated without regard
* to the current binary flag. Names may start with "/",
* then they represent full names (we don't produce such names),
* otherwise names are relative to current directory.
* Embedded "\n" are replaced by NULs. This is safe since names
* can never contain NUL.
*/
handle_dir_common(0);
}
static void
handle_stat_file(void)
{
handle_dir_common(LONG_LISTING USE_CTRL_CONN);
}
/* This can be extended to handle MLST, as all info is available
* in struct stat for that:
* MLST file_name
* 250-Listing file_name
* type=file;size=4161;modify=19970214165800; /dir/dir/file_name
* 250 End
* Nano-doc:
* MLST [<file or dir name, "." assumed if not given>]
* Returned name should be either the same as requested, or fully qualified.
* If there was no parameter, return "" or (preferred) fully-qualified name.
* Returned "facts" (case is not important):
* size - size in octets
* modify - last modification time
* type - entry type (file,dir,OS.unix=block)
* ( cdir and pdir types for MLSD)
* unique - unique id of file/directory (inode#)
* perm -
* a: can be appended to (APPE)
* d: can be deleted (RMD/DELE)
* f: can be renamed (RNFR)
* r: can be read (RETR)
* w: can be written (STOR)
* e: can CWD into this dir
* l: this dir can be listed (dir only!)
* c: can create files in this dir
* m: can create dirs in this dir (MKD)
* p: can delete files in this dir
* UNIX.mode - unix file mode
*/
static void
handle_size_or_mdtm(int need_size)
{
struct stat statbuf;
struct tm broken_out;
char buf[(sizeof("NNN %"OFF_FMT"u\r\n") sizeof(off_t) * 3)
| sizeof("NNN YYYYMMDDhhmmss\r\n")
];
if (!G.ftp_arg
|| stat(G.ftp_arg, &statbuf) != 0
|| !S_ISREG(statbuf.st_mode)
) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
if (need_size) {
sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
} else {
gmtime_r(&statbuf.st_mtime, &broken_out);
sprintf(buf, STR(FTP_STATFILE_OK)" uuuuuu\r\n",
broken_out.tm_year 1900,
broken_out.tm_mon,
broken_out.tm_mday,
broken_out.tm_hour,
broken_out.tm_min,
broken_out.tm_sec);
}
cmdio_write_raw(buf);
}
/* Upload commands */
#if ENABLE_FEATURE_FTP_WRITE
static void
handle_mkd(void)
{
if (!G.ftp_arg || mkdir(G.ftp_arg, 0777) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_MKDIROK);
}
static void
handle_rmd(void)
{
if (!G.ftp_arg || rmdir(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_RMDIROK);
}
static void
handle_dele(void)
{
if (!G.ftp_arg || unlink(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_DELEOK);
}
static void
handle_rnfr(void)
{
free(G.rnfr_filename);
G.rnfr_filename = xstrdup(G.ftp_arg);
WRITE_OK(FTP_RNFROK);
}
static void
handle_rnto(void)
{
int retval;
/* If we didn't get a RNFR, throw a wobbly */
if (G.rnfr_filename == NULL || G.ftp_arg == NULL) {
cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n");
return;
}
retval = rename(G.rnfr_filename, G.ftp_arg);
free(G.rnfr_filename);
G.rnfr_filename = NULL;
if (retval) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_RENAMEOK);
}
static void
handle_upload_common(int is_append, int is_unique)
{
struct stat statbuf;
char *tempname;
off_t bytes_transferred;
off_t offset;
int local_file_fd;
int remote_fd;
offset = G.restart_pos;
G.restart_pos = 0;
if (!port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
tempname = NULL;
local_file_fd = -1;
if (is_unique) {
tempname = xstrdup(" FILE: uniq.XXXXXX");
local_file_fd = mkstemp(tempname 7);
} else if (G.ftp_arg) {
int flags = O_WRONLY | O_CREAT | O_TRUNC;
if (is_append)
flags = O_WRONLY | O_CREAT | O_APPEND;
if (offset)
flags = O_WRONLY | O_CREAT;
local_file_fd = open(G.ftp_arg, flags, 0666);
}
if (local_file_fd < 0
|| fstat(local_file_fd, &statbuf) != 0
|| !S_ISREG(statbuf.st_mode)
) {
WRITE_ERR(FTP_UPLOADFAIL);
if (local_file_fd >= 0)
goto close_local_and_bail;
return;
}
G.local_file_fd = local_file_fd;
if (offset)
xlseek(local_file_fd, offset, SEEK_SET);
remote_fd = get_remote_transfer_fd(tempname ? tempname : " Ok to send data");
free(tempname);
if (remote_fd < 0)
goto close_local_and_bail;
bytes_transferred = bb_copyfd_eof(remote_fd, local_file_fd);
close(remote_fd);
if (bytes_transferred < 0)
WRITE_ERR(FTP_BADSENDFILE);
else
WRITE_OK(FTP_TRANSFEROK);
close_local_and_bail:
close(local_file_fd);
G.local_file_fd = 0;
}
static void
handle_stor(void)
{
handle_upload_common(0, 0);
}
static void
handle_appe(void)
{
G.restart_pos = 0;
handle_upload_common(1, 0);
}
static void
handle_stou(void)
{
G.restart_pos = 0;
handle_upload_common(0, 1);
}
#endif /* ENABLE_FEATURE_FTP_WRITE */
static uint32_t
cmdio_get_cmd_and_arg(void)
{
int len;
uint32_t cmdval;
char *cmd;
alarm(G.timeout);
free(G.ftp_cmd);
{
/* Paranoia. Peer may send 1 gigabyte long cmd... */
/* Using separate len_on_stk instead of len optimizes
* code size (allows len to be in CPU register) */
size_t len_on_stk = 8 * 1024;
G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len_on_stk);
if (!cmd)
exit(0);
len = len_on_stk;
}
/* De-escape telnet: 0xff,0xff => 0xff */
/* RFC959 says that ABOR, STAT, QUIT may be sent even during
* data transfer, and may be preceded by telnet's "Interrupt Process"
* code (two-byte sequence 255,244) and then by telnet "Synch" code
* 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
* and may generate SIGURG on our side. See RFC854).
* So far we don't support that (may install SIGURG handler if we'd want to),
* but we need to at least remove 255,xxx pairs. lftp sends those. */
/* Then de-escape FTP: NUL => '\n' */
/* Testing for \xff:
* Create file named '\xff': echo Hello >`echo -ne "\xff"`
* Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
* (need "\xff\xff" until ftpget applet is fixed to do escaping :)
* Testing for embedded LF:
* LF_HERE=`echo -ne "LF\nHERE"`
* echo Hello >"$LF_HERE"
* ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
*/
{
int dst, src;
/* Strip "\r\n" if it is there */
if (len != 0 && cmd[len - 1] == '\n') {
len--;
if (len != 0 && cmd[len - 1] == '\r')
len--;
cmd[len] = '\0';
}
src = strchrnul(cmd, 0xff) - cmd;
/* 99,99% there are neither NULs nor 255s and src == len */
if (src < len) {
dst = src;
do {
if ((unsigned char)(cmd[src]) == 255) {
src ;
/* 255,xxx - skip 255 */
if ((unsigned char)(cmd[src]) != 255) {
/* 255,!255 - skip both */
src ;
continue;
}
/* 255,255 - retain one 255 */
}
/* NUL => '\n' */
cmd[dst ] = cmd[src] ? cmd[src] : '\n';
src ;
} while (src < len);
cmd[dst] = '\0';
}
}
if (G.verbose > 1)
verbose_log(cmd);
G.ftp_arg = strchr(cmd, ' ');
if (G.ftp_arg != NULL)
*G.ftp_arg = '\0';
/* Uppercase and pack into uint32_t first word of the command */
cmdval = 0;
while (*cmd)
cmdval = (cmdval << 8) ((unsigned char)*cmd & (unsigned char)~0x20);
return cmdval;
}
#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)
enum {
const_ALLO = mk_const4('A', 'L', 'L', 'O'),
const_APPE = mk_const4('A', 'P', 'P', 'E'),
const_CDUP = mk_const4('C', 'D', 'U', 'P'),
const_CWD = mk_const3('C', 'W', 'D'),
const_DELE = mk_const4('D', 'E', 'L', 'E'),
const_EPSV = mk_const4('E', 'P', 'S', 'V'),
const_FEAT = mk_const4('F', 'E', 'A', 'T'),
const_HELP = mk_const4('H', 'E', 'L', 'P'),
const_LIST = mk_const4('L', 'I', 'S', 'T'),
const_MDTM = mk_const4('M', 'D', 'T', 'M'),
const_MKD = mk_const3('M', 'K', 'D'),
const_MODE = mk_const4('M', 'O', 'D', 'E'),
const_NLST = mk_const4('N', 'L', 'S', 'T'),
const_NOOP = mk_const4('N', 'O', 'O', 'P'),
const_PASS = mk_const4('P', 'A', 'S', 'S'),
const_PASV = mk_const4('P', 'A', 'S', 'V'),
const_PORT = mk_const4('P', 'O', 'R', 'T'),
const_PWD = mk_const3('P', 'W', 'D'),
const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
const_REST = mk_const4('R', 'E', 'S', 'T'),
const_RETR = mk_const4('R', 'E', 'T', 'R'),
const_RMD = mk_const3('R', 'M', 'D'),
const_RNFR = mk_const4('R', 'N', 'F', 'R'),
const_RNTO = mk_const4('R', 'N', 'T', 'O'),
const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
const_STAT = mk_const4('S', 'T', 'A', 'T'),
const_STOR = mk_const4('S', 'T', 'O', 'R'),
const_STOU = mk_const4('S', 'T', 'O', 'U'),
const_STRU = mk_const4('S', 'T', 'R', 'U'),
const_SYST = mk_const4('S', 'Y', 'S', 'T'),
const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
const_USER = mk_const4('U', 'S', 'E', 'R'),
#if !BB_MMU
OPT_l = (1 << 0),
OPT_1 = (1 << 1),
#endif
OPT_v = (1 << ((!BB_MMU) * 2 0)),
OPT_S = (1 << ((!BB_MMU) * 2 1)),
OPT_w = (1 << ((!BB_MMU) * 2 2)) * ENABLE_FEATURE_FTP_WRITE,
};
//wsm add
#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
static int parse_username(char *user_list,char *user)//该函数是用来验证用户名的
{
FILE *stream;
char buf[100];
bzero(buf,sizeof(buf));
if((stream = fopen(user_list,"r"))==NULL)
{
//puts("file /etc/ftpusers open fail! \n");
return 0;
}
while ((fgets (buf, 100, stream)) != NULL)
{
buf[strlen(buf)-1]='\0';
if((buf[0]!='#')&&(strcmp(buf,user)==0))
{
//puts("user is accept !\n");
fclose(stream);
return 1;
}
}
fclose(stream);
//puts("user is refuse !\n");
return 0;
}
static int parse_username_password(char *user,char *password)//该函数是用来验证用户名对应的密码的
{
const char *cpwd = NULL;
struct passwd *pw;
struct spwd *spw;
char *crypt_pw;
pw=getpwnam(user);
if(pw)
{
if ((((pw->pw_passwd)[0] == 'x' && (pw->pw_passwd)[1] == 0) || \
((pw->pw_passwd)[0] == '#' && (pw->pw_passwd)[1] == '#' && \
strcmp(pw->pw_passwd 2, user) == 0)) && \
(spw = getspnam(user)) != NULL && spw->sp_pwdp != NULL)
{
cpwd = spw->sp_pwdp[0] == '@' ? NULL : spw->sp_pwdp;
}
else
{
cpwd= pw->pw_passwd;
}
crypt_pw = crypt(password,cpwd);
if (strcmp(cpwd,crypt_pw)==0)
{
//printf("Success!\n");
return 1;
}
else
{
//printf("Password is not correct!\n");
return 0;
}
}
else
{
//printf("Unknown User!\n");
return 0;
}
}
#endif
//end wsm
int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
#if !BB_MMU
int ftpd_main(int argc, char **argv)
#else
int ftpd_main(int argc UNUSED_PARAM, char **argv)
#endif
{
unsigned abs_timeout;
unsigned verbose_S;
smallint opts;
char user[50];//wsm add
char user_list[50]="/etc/ftpusers";//wsm add
INIT_G();
abs_timeout = 1 * 60 * 60;
verbose_S = 0;
G.timeout = 2 * 60;
opt_complementary = "t :T :vv:SS";
#if BB_MMU
opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
#else
opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
if (opts & (OPT_l|OPT_1)) {
/* Our secret backdoor to ls */
/* TODO: pass -n? It prevents user/group resolution, which may not work in chroot anyway */
/* TODO: pass -A? It shows dot files */
/* TODO: pass --group-directories-first? would be nice, but ls doesn't do that yet */
xchdir(argv[2]);
argv[2] = (char*)"--";
/* memset(&G, 0, sizeof(G)); - ls_main does it */
return ls_main(argc, argv);
}
#endif
if (G.verbose < verbose_S)
G.verbose = verbose_S;
if (abs_timeout | G.timeout) {
if (abs_timeout == 0)
abs_timeout = INT_MAX;
G.end_time = monotonic_sec() abs_timeout;
if (G.timeout > abs_timeout)
G.timeout = abs_timeout;
}
strcpy(G.msg_ok 4, MSG_OK );
strcpy(G.msg_err 4, MSG_ERR);
G.local_addr = get_sock_lsa(STDIN_FILENO);
if (!G.local_addr) {
/* This is confusing:
* bb_error_msg_and_die("stdin is not a socket");
* Better: */
bb_show_usage();
/* Help text says that ftpd must be used as inetd service,
* which is by far the most usual cause of get_sock_lsa
* failure */
}
if (!(opts & OPT_v))
logmode = LOGMODE_NONE;
if (opts & OPT_S) {
/* LOG_NDELAY is needed since we may chroot later */
openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
logmode |= LOGMODE_SYSLOG;
}
if (logmode)
applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
#if !BB_MMU
G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
close_on_exec_on(G.root_fd);
#endif
if (argv[optind]) {
xchdir(argv[optind]);
chroot(".");
}
//wsm add 该段代码是用来读取出被允许的用户列表文件的路径，只有在该列表中的用户才被允许登陆
if(argv[optind 1])
{
strcpy(user_list,argv[optind 1]);
}
//end wsm
//umask(077); - admin can set umask before starting us
/* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
signal(SIGPIPE, SIG_IGN);
/* Set up options on the command socket (do we need these all? why?) */
setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
/* Telnet protocol over command link may send "urgent" data,
* we prefer it to be received in the "normal" data stream: */
setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
WRITE_OK(FTP_GREET);
signal(SIGALRM, timeout_handler);
#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
{
smallint user_was_specified = 0;
while (1) {
uint32_t cmdval = cmdio_get_cmd_and_arg();
if (cmdval == const_USER) {
//if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)//wsm dec
if (G.ftp_arg == NULL || parse_username(user_list,G.ftp_arg) == 0)//wsm
cmdio_write_raw(STR(FTP_LOGINERR)" user is refuse\r\n");//wsm ch
else {
user_was_specified = 1;
strcpy(user,G.ftp_arg);
cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
}
} else if (cmdval == const_PASS) {
if (user_was_specified)
{
if(parse_username_password(user,G.ftp_arg))
{
break;
}
cmdio_write_raw(STR(FTP_LOGINERR)" password error\r\n");
}
else
{
cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
}
} else if (cmdval == const_QUIT) {
WRITE_OK(FTP_GOODBYE);
return 0;
} else {
cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
}
}
}
WRITE_OK(FTP_LOGINOK);
#endif
/* RFC-959 Section 5.1
* The following commands and options MUST be supported by every
* server-FTP and user-FTP, except in cases where the underlying
* file system or operating system does not allow or support
* a particular command.
* Type: ASCII Non-print, IMAGE, LOCAL 8
* Mode: Stream
* Structure: File, Record*
* (Record structure is REQUIRED only for hosts whose file
* systems support record structure).
* Commands:
* USER, PASS, ACCT, [bbox: ACCT not supported]
* PORT, PASV,
* TYPE, MODE, STRU,
* RETR, STOR, APPE,
* RNFR, RNTO, DELE,
* CWD, CDUP, RMD, MKD, PWD,
* LIST, NLST,
* SYST, STAT,
* HELP, NOOP, QUIT.
*/
/* ACCOUNT (ACCT)
* "The argument field is a Telnet string identifying the user's account.
* The command is not necessarily related to the USER command, as some
* sites may require an account for login and others only for specific
* access, such as storing files. In the latter case the command may
* arrive at any time.
* There are reply codes to differentiate these cases for the automation:
* when account information is required for login, the response to
* a successful PASSword command is reply code 332. On the other hand,
* if account information is NOT required for login, the reply to
* a successful PASSword command is 230; and if the account information
* is needed for a command issued later in the dialogue, the server
* should return a 332 or 532 reply depending on whether it stores
* (pending receipt of the ACCounT command) or discards the command,
* respectively."
*/
while (1) {
uint32_t cmdval = cmdio_get_cmd_and_arg();
if (cmdval == const_QUIT) {
WRITE_OK(FTP_GOODBYE);
return 0;
}
else if (cmdval == const_USER)
/* This would mean "ok, now give me PASS". */
/*WRITE_OK(FTP_GIVEPWORD);*/
/* vsftpd can be configured to not require that,
* and this also saves one roundtrip:
*/
WRITE_OK(FTP_LOGINOK);
else if (cmdval == const_PASS)
WRITE_OK(FTP_LOGINOK);
else if (cmdval == const_NOOP)
WRITE_OK(FTP_NOOPOK);
else if (cmdval == const_TYPE)
WRITE_OK(FTP_TYPEOK);
else if (cmdval == const_STRU)
WRITE_OK(FTP_STRUOK);
else if (cmdval == const_MODE)
WRITE_OK(FTP_MODEOK);
else if (cmdval == const_ALLO)
WRITE_OK(FTP_ALLOOK);
else if (cmdval == const_SYST)
cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
else if (cmdval == const_PWD)
handle_pwd();
else if (cmdval == const_CWD)
handle_cwd();
else if (cmdval == const_CDUP) /* cd .. */
handle_cdup();
/* HELP is nearly useless, but we can reuse FEAT for it */
/* lftp uses FEAT */
else if (cmdval == const_HELP || cmdval == const_FEAT)
handle_feat(cmdval == const_HELP
? STRNUM32(FTP_HELP)
: STRNUM32(FTP_STATOK)
);
else if (cmdval == const_LIST) /* ls -l */
handle_list();
else if (cmdval == const_NLST) /* "name list", bare ls */
handle_nlst();
/* SIZE is crucial for wget's download indicator etc */
/* Mozilla, lftp use MDTM (presumably for caching) */
else if (cmdval == const_SIZE || cmdval == const_MDTM)
handle_size_or_mdtm(cmdval == const_SIZE);
else if (cmdval == const_STAT) {
if (G.ftp_arg == NULL)
handle_stat();
else
handle_stat_file();
}
else if (cmdval == const_PASV)
handle_pasv();
else if (cmdval == const_EPSV)
handle_epsv();
else if (cmdval == const_RETR)
handle_retr();
else if (cmdval == const_PORT)
handle_port();
else if (cmdval == const_REST)
handle_rest();
#if ENABLE_FEATURE_FTP_WRITE
else if (opts & OPT_w) {
if (cmdval == const_STOR)
handle_stor();
else if (cmdval == const_MKD)
handle_mkd();
else if (cmdval == const_RMD)
handle_rmd();
else if (cmdval == const_DELE)
handle_dele();
else if (cmdval == const_RNFR) /* "rename from" */
handle_rnfr();
else if (cmdval == const_RNTO) /* "rename to" */
handle_rnto();
else if (cmdval == const_APPE)
handle_appe();
else if (cmdval == const_STOU) /* "store unique" */
handle_stou();
else
goto bad_cmd;
}
#endif
#if 0
else if (cmdval == const_STOR
|| cmdval == const_MKD
|| cmdval == const_RMD
|| cmdval == const_DELE
|| cmdval == const_RNFR
|| cmdval == const_RNTO
|| cmdval == const_APPE
|| cmdval == const_STOU
) {
cmdio_write_raw(STR(FTP_NOPERM)" Permission denied\r\n");
}
#endif
else {
/* Which unsupported commands were seen in the wild?
* (doesn't necessarily mean "we must support them")
* foo 1.2.3: XXXX - comment
*/
#if ENABLE_FEATURE_FTP_WRITE
bad_cmd:
#endif
cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");
}
}
}
tcpsvd 0 21 ftpd -w / -t 5 /etc/ftpusers
上面是我的启动ftpd服务器的命令
第一个‘/’是ftpd服务器的共享目录，“/etc/ftpusers”是被允许的用户列表文件，用户可以根据实际路径改变，用户列表文件的格式为每一行一个用户名，不允许的用户删除该行或者用#注释掉即可，另外要求用户列表文件路径必须在共享目录路径的后面。
因为项目用到了ftp传输文件的功能，设备要做ftp服务器，正好busybox有ftpd这个功能，所以就直接使用啦，但是测试发现，自带的这个ftpd登陆根本就不需要用户名和密码，所以这就有安全隐患了，这是不允许滴，搜索资料表明，搜不到关于ftpd用户名和密码登陆的问题，都是使用另外一个工具，lftp，于是我就编译了一个lftp，测试可以使用，但是因为编译的时候总是不过，需要屏蔽掉一些功能才可以编译通过，所以总觉得有隐患，于是决定再次研究一下ftpd为什么不能用户名和密码登陆，网上既然查不到，那只好自己去研究源代码啦，看到了ftpd的源代码文件ftpd.c里面有一个IF_WE_WANT_TO_REQUIRE_LOGIN，就是用来配置是否需要用户名和密码登陆的，可是这个宏却不能在busybox的make
xconfig中配置，所以我猜想肯定是因为这个功能还不完善，所以才不能配置的，于是自己在代码中打开试一下，编译通过，测试显示失败，于是查找代码发现，if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)，该if判断只要是匿名用户就可以登陆，而且后续没有对密码的验证，既然这样，那就只好自己实现啦，我的busybox的版本是1.17.2，一下是我的代码，里面所有在//wsm add和//end wsm之间的代码都是我添加的，你们可以和官方的未修改版进行对比就知道区别啦，代码如下，主要函数和代码我已经做了注释。
/* vi: set sw=4 ts=4: */
/*
* Simple FTP daemon, based on vsftpd 2.0.7 (written by Chris Evans)
*
* Author: Adam Tkac <vonsch@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*
* Only subset of FTP protocol is implemented but vast majority of clients
* should not have any problem.
*
* You have to run this daemon via inetd.
*/
#include "libbb.h"
#include <syslog.h>
#include <netinet/tcp.h>
//wsm add
#include <unistd.h>
#include <stdio.h>
#include <netinet/in.h>
#include <pwd.h>
#include <stdlib.h>
#include <crypt.h>
#include <string.h>
#include <shadow.h>
#define IF_WE_WANT_TO_REQUIRE_LOGIN
//end wsm
#define FTP_DATACONN 150
#define FTP_NOOPOK 200
#define FTP_TYPEOK 200
#define FTP_PORTOK 200
#define FTP_STRUOK 200
#define FTP_MODEOK 200
#define FTP_ALLOOK 202
#define FTP_STATOK 211
#define FTP_STATFILE_OK 213
#define FTP_HELP 214
#define FTP_SYSTOK 215
#define FTP_GREET 220
#define FTP_GOODBYE 221
#define FTP_TRANSFEROK 226
#define FTP_PASVOK 227
/*#define FTP_EPRTOK 228*/
#define FTP_EPSVOK 229
#define FTP_LOGINOK 230
#define FTP_CWDOK 250
#define FTP_RMDIROK 250
#define FTP_DELEOK 250
#define FTP_RENAMEOK 250
#define FTP_PWDOK 257
#define FTP_MKDIROK 257
#define FTP_GIVEPWORD 331
#define FTP_RESTOK 350
#define FTP_RNFROK 350
#define FTP_TIMEOUT 421
#define FTP_BADSENDCONN 425
#define FTP_BADSENDNET 426
#define FTP_BADSENDFILE 451
#define FTP_BADCMD 500
#define FTP_COMMANDNOTIMPL 502
#define FTP_NEEDUSER 503
#define FTP_NEEDRNFR 503
#define FTP_BADSTRU 504
#define FTP_BADMODE 504
#define FTP_LOGINERR 530
#define FTP_FILEFAIL 550
#define FTP_NOPERM 550
#define FTP_UPLOADFAIL 553
#define STR1(s) #s
#define STR(s) STR1(s)
/* Convert a constant to 3-digit string, packed into uint32_t */
enum {
/* Shift for Nth decimal digit */
SHIFT2 = 0 * BB_LITTLE_ENDIAN 24 * BB_BIG_ENDIAN,
SHIFT1 = 8 * BB_LITTLE_ENDIAN 16 * BB_BIG_ENDIAN,
SHIFT0 = 16 * BB_LITTLE_ENDIAN 8 * BB_BIG_ENDIAN,
/* And for 4th position (space) */
SHIFTsp = 24 * BB_LITTLE_ENDIAN 0 * BB_BIG_ENDIAN,
};
#define STRNUM32(s) (uint32_t)(0 \
| (('0' ((s) / 1 % 10)) << SHIFT0) \
| (('0' ((s) / 10 % 10)) << SHIFT1) \
| (('0' ((s) / 100 % 10)) << SHIFT2) \
)
#define STRNUM32sp(s) (uint32_t)(0 \
| (' ' << SHIFTsp) \
| (('0' ((s) / 1 % 10)) << SHIFT0) \
| (('0' ((s) / 10 % 10)) << SHIFT1) \
| (('0' ((s) / 100 % 10)) << SHIFT2) \
)
#define MSG_OK "Operation successful\r\n"
#define MSG_ERR "Error\r\n"
struct globals {
int pasv_listen_fd;
#if !BB_MMU
int root_fd;
#endif
int local_file_fd;
unsigned end_time;
unsigned timeout;
unsigned verbose;
off_t local_file_pos;
off_t restart_pos;
len_and_sockaddr *local_addr;
len_and_sockaddr *port_addr;
char *ftp_cmd;
char *ftp_arg;
#if ENABLE_FEATURE_FTP_WRITE
char *rnfr_filename;
#endif
/* We need these aligned to uint32_t */
char msg_ok [(sizeof("NNN " MSG_OK ) 3) & 0xfffc];
char msg_err[(sizeof("NNN " MSG_ERR) 3) & 0xfffc];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
/* Moved to main */ \
/*strcpy(G.msg_ok 4, MSG_OK );*/ \
/*strcpy(G.msg_err 4, MSG_ERR);*/ \
} while (0)
static char *
escape_text(const char *prepend, const char *str, unsigned escapee)
{
unsigned retlen, remainlen, chunklen;
char *ret, *found;
char append;
append = (char)escapee;
escapee >>= 8;
remainlen = strlen(str);
retlen = strlen(prepend);
ret = xmalloc(retlen remainlen * 2 1 1);
strcpy(ret, prepend);
for (;;) {
found = strchrnul(str, escapee);
chunklen = found - str 1;
/* Copy chunk up to and including escapee (or NUL) to ret */
memcpy(ret retlen, str, chunklen);
retlen = chunklen;
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;
}
/* Returns strlen as a bonus */
static unsigned
replace_char(char *str, char from, char to)
{
char *p = str;
while (*p) {
if (*p == from)
*p = to;
p ;
}
return p - str;
}
static void
verbose_log(const char *str)
{
bb_error_msg("%.*s", (int)strcspn(str, "\r\n"), str);
}
/* NB: status_str is char[4] packed into uint32_t */
static void
cmdio_write(uint32_t status_str, const char *str)
{
char *response;
int len;
/* FTP uses telnet protocol for command link.
* In telnet, 0xff is an escape char, and needs to be escaped: */
response = escape_text((char *) &status_str, str, (0xff << 8) '\r');
/* FTP sends embedded LFs as NULs */
len = replace_char(response, '\n', '\0');
response[len ] = '\n'; /* tack on trailing '\n' */
xwrite(STDOUT_FILENO, response, len);
if (G.verbose > 1)
verbose_log(response);
free(response);
}
static void
cmdio_write_ok(unsigned status)
{
*(uint32_t *) G.msg_ok = status;
xwrite(STDOUT_FILENO, G.msg_ok, sizeof("NNN " MSG_OK) - 1);
if (G.verbose > 1)
verbose_log(G.msg_ok);
}
#define WRITE_OK(a) cmdio_write_ok(STRNUM32sp(a))
/* TODO: output strerr(errno) if errno != 0? */
static void
cmdio_write_error(unsigned status)
{
*(uint32_t *) G.msg_err = status;
xwrite(STDOUT_FILENO, G.msg_err, sizeof("NNN " MSG_ERR) - 1);
if (G.verbose > 1)
verbose_log(G.msg_err);
}
#define WRITE_ERR(a) cmdio_write_error(STRNUM32sp(a))
static void
cmdio_write_raw(const char *p_text)
{
xwrite_str(STDOUT_FILENO, p_text);
if (G.verbose > 1)
verbose_log(p_text);
}
static void
timeout_handler(int sig UNUSED_PARAM)
{
off_t pos;
int sv_errno = errno;
if ((int)(monotonic_sec() - G.end_time) >= 0)
goto timed_out;
if (!G.local_file_fd)
goto timed_out;
pos = xlseek(G.local_file_fd, 0, SEEK_CUR);
if (pos == G.local_file_pos)
goto timed_out;
G.local_file_pos = pos;
alarm(G.timeout);
errno = sv_errno;
return;
timed_out:
cmdio_write_raw(STR(FTP_TIMEOUT)" Timeout\r\n");
/* TODO: do we need to abort (as opposed to usual shutdown) data transfer? */
exit(1);
}
/* Simple commands */
static void
handle_pwd(void)
{
char *cwd, *response;
cwd = xrealloc_getcwd_or_warn(NULL);
if (cwd == NULL)
cwd = xstrdup("");
/* We have to promote each " to "" */
response = escape_text(" \"", cwd, ('"' << 8) '"');
free(cwd);
cmdio_write(STRNUM32(FTP_PWDOK), response);
free(response);
}
static void
handle_cwd(void)
{
if (!G.ftp_arg || chdir(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_CWDOK);
}
static void
handle_cdup(void)
{
G.ftp_arg = (char*)"..";
handle_cwd();
}
static void
handle_stat(void)
{
cmdio_write_raw(STR(FTP_STATOK)"-Server status:\r\n"
" TYPE: BINARY\r\n"
STR(FTP_STATOK)" Ok\r\n");
}
/* Examples of HELP and FEAT:
# nc -vvv ftp.kernel.org 21
ftp.kernel.org (130.239.17.4:21) open
220 Welcome to ftp.kernel.org.
FEAT
211-Features:
EPRT
EPSV
MDTM
PASV
REST STREAM
SIZE
TVFS
UTF8
211 End
HELP
214-The following commands are recognized.
ABOR ACCT ALLO APPE CDUP CWD DELE EPRT EPSV FEAT HELP LIST MDTM MKD
MODE NLST NOOP OPTS PASS PASV PORT PWD QUIT REIN REST RETR RMD RNFR
RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
XPWD XRMD
214 Help OK.
*/
static void
handle_feat(unsigned status)
{
cmdio_write(status, "-Features:");
cmdio_write_raw(" EPSV\r\n"
" PASV\r\n"
" REST STREAM\r\n"
" MDTM\r\n"
" SIZE\r\n");
cmdio_write(status, " Ok");
}
/* Download commands */
static inline int
port_active(void)
{
return (G.port_addr != NULL);
}
static inline int
pasv_active(void)
{
return (G.pasv_listen_fd > STDOUT_FILENO);
}
static void
port_pasv_cleanup(void)
{
free(G.port_addr);
G.port_addr = NULL;
if (G.pasv_listen_fd > STDOUT_FILENO)
close(G.pasv_listen_fd);
G.pasv_listen_fd = -1;
}
/* On error, emits error code to the peer */
static int
ftpdataio_get_pasv_fd(void)
{
int remote_fd;
remote_fd = accept(G.pasv_listen_fd, NULL, 0);
if (remote_fd < 0) {
WRITE_ERR(FTP_BADSENDCONN);
return remote_fd;
}
setsockopt(remote_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
return remote_fd;
}
/* Clears port/pasv data.
* This means we dont waste resources, for example, keeping
* PASV listening socket open when it is no longer needed.
* On error, emits error code to the peer (or exits).
* On success, emits p_status_msg to the peer.
*/
static int
get_remote_transfer_fd(const char *p_status_msg)
{
int remote_fd;
if (pasv_active())
/* On error, emits error code to the peer */
remote_fd = ftpdataio_get_pasv_fd();
else
/* Exits on error */
remote_fd = xconnect_stream(G.port_addr);
port_pasv_cleanup();
if (remote_fd < 0)
return remote_fd;
cmdio_write(STRNUM32(FTP_DATACONN), p_status_msg);
return remote_fd;
}
/* If there were neither PASV nor PORT, emits error code to the peer */
static int
port_or_pasv_was_seen(void)
{
if (!pasv_active() && !port_active()) {
cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT/PASV first\r\n");
return 0;
}
return 1;
}
/* Exits on error */
static unsigned
bind_for_passive_mode(void)
{
int fd;
unsigned port;
port_pasv_cleanup();
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(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;
}
/* Exits on error */
static void
handle_pasv(void)
{
unsigned port;
char *addr, *response;
port = bind_for_passive_mode();
if (G.local_addr->u.sa.sa_family == AF_INET)
addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
else /* seen this in the wild done by other ftp servers: */
addr = xstrdup("0.0.0.0");
replace_char(addr, '.', ',');
response = xasprintf(STR(FTP_PASVOK)" PASV ok (%s,%u,%u)\r\n",
addr, (int)(port >> 8), (int)(port & 255));
free(addr);
cmdio_write_raw(response);
free(response);
}
/* Exits on error */
static void
handle_epsv(void)
{
unsigned port;
char *response;
port = bind_for_passive_mode();
response = xasprintf(STR(FTP_EPSVOK)" EPSV ok (|||%u|)\r\n", port);
cmdio_write_raw(response);
free(response);
}
static void
handle_port(void)
{
unsigned port, port_hi;
char *raw, *comma;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
socklen_t peer_ipv4_len;
struct sockaddr_in peer_ipv4;
struct in_addr port_ipv4_sin_addr;
#endif
port_pasv_cleanup();
raw = G.ftp_arg;
/* PORT command format makes sense only over IPv4 */
if (!raw
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
|| G.local_addr->u.sa.sa_family != AF_INET
#endif
) {
bail:
WRITE_ERR(FTP_BADCMD);
return;
}
comma = strrchr(raw, ',');
if (comma == NULL)
goto bail;
*comma = '\0';
port = bb_strtou(&comma[1], NULL, 10);
if (errno || port > 0xff)
goto bail;
comma = strrchr(raw, ',');
if (comma == NULL)
goto bail;
*comma = '\0';
port_hi = bb_strtou(&comma[1], NULL, 10);
if (errno || port_hi > 0xff)
goto bail;
port |= port_hi << 8;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
replace_char(raw, ',', '.');
/* We are verifying that PORT's IP matches getpeername().
* Otherwise peer can make us open data connections
* to other hosts (security problem!)
* This code would be too simplistic:
* lsa = xdotted2sockaddr(raw, port);
* if (lsa == NULL) goto bail;
*/
if (!inet_aton(raw, &port_ipv4_sin_addr))
goto bail;
peer_ipv4_len = sizeof(peer_ipv4);
if (getpeername(STDIN_FILENO, &peer_ipv4, &peer_ipv4_len) != 0)
goto bail;
if (memcmp(&port_ipv4_sin_addr, &peer_ipv4.sin_addr, sizeof(struct in_addr)) != 0)
goto bail;
G.port_addr = xdotted2sockaddr(raw, port);
#else
G.port_addr = get_peer_lsa(STDIN_FILENO);
set_nport(G.port_addr, htons(port));
#endif
WRITE_OK(FTP_PORTOK);
}
static void
handle_rest(void)
{
/* When ftp_arg == NULL simply restart from beginning */
G.restart_pos = G.ftp_arg ? xatoi_u(G.ftp_arg) : 0;
WRITE_OK(FTP_RESTOK);
}
static void
handle_retr(void)
{
struct stat statbuf;
off_t bytes_transferred;
int remote_fd;
int local_file_fd;
off_t offset = G.restart_pos;
char *response;
G.restart_pos = 0;
if (!port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
/* O_NONBLOCK is useful if file happens to be a device node */
local_file_fd = G.ftp_arg ? open(G.ftp_arg, O_RDONLY | O_NONBLOCK) : -1;
if (local_file_fd < 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
if (fstat(local_file_fd, &statbuf) != 0 || !S_ISREG(statbuf.st_mode)) {
/* Note - pretend open failed */
WRITE_ERR(FTP_FILEFAIL);
goto file_close_out;
}
G.local_file_fd = local_file_fd;
/* Now deactive O_NONBLOCK, otherwise we have a problem
* on DMAPI filesystems such as XFS DMAPI.
*/
ndelay_off(local_file_fd);
/* Set the download offset (from REST) if any */
if (offset != 0)
xlseek(local_file_fd, offset, SEEK_SET);
response = xasprintf(
" Opening BINARY connection for %s (%"OFF_FMT"u bytes)",
G.ftp_arg, statbuf.st_size);
remote_fd = get_remote_transfer_fd(response);
free(response);
if (remote_fd < 0)
goto file_close_out;
bytes_transferred = bb_copyfd_eof(local_file_fd, remote_fd);
close(remote_fd);
if (bytes_transferred < 0)
WRITE_ERR(FTP_BADSENDFILE);
else
WRITE_OK(FTP_TRANSFEROK);
file_close_out:
close(local_file_fd);
G.local_file_fd = 0;
}
/* List commands */
static int
popen_ls(const char *opt)
{
const char *argv[5];
struct fd_pair outfd;
pid_t pid;
argv[0] = "ftpd";
argv[1] = opt; /* "-l" or "-1" */
#if BB_MMU
argv[2] = "--";
#else
/* NOMMU ftpd ls helper chdirs to argv[2],
* preventing peer from seeing real root. */
argv[2] = xrealloc_getcwd_or_warn(NULL);
#endif
argv[3] = G.ftp_arg;
argv[4] = NULL;
/* Improve compatibility with non-RFC conforming FTP clients
* which send e.g. "LIST -l", "LIST -la", "LIST -aL".
* See https://bugs.kde.org/show_bug.cgi?id=195578 */
if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST
&& G.ftp_arg && G.ftp_arg[0] == '-'
) {
const char *tmp = strchr(G.ftp_arg, ' ');
if (tmp) /* skip the space */
tmp ;
argv[3] = tmp;
}
xpiped_pair(outfd);
/*fflush_all(); - so far we dont use stdio on output */
pid = BB_MMU ? xfork() : xvfork();
if (pid == 0) {
/* child */
#if !BB_MMU
/* On NOMMU, we want to execute a child - copy of ourself.
* In chroot we usually can't do it. Thus we chdir
* out of the chroot back to original root,
* and (see later below) execute bb_busybox_exec_path
* relative to current directory */
if (fchdir(G.root_fd) != 0)
_exit(127);
/*close(G.root_fd); - close_on_exec_on() took care of this */
#endif
/* NB: close _first_, then move fd! */
close(outfd.rd);
xmove_fd(outfd.wr, STDOUT_FILENO);
/* Opening /dev/null in chroot is hard.
* Just making sure STDIN_FILENO is opened
* to something harmless. Paranoia,
* ls won't read it anyway */
close(STDIN_FILENO);
dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
#if BB_MMU
/* memset(&G, 0, sizeof(G)); - ls_main does it */
exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
#else
/* 1: we must use relative path here if in chroot.
* For example, execv("/proc/self/exe") will fail, since
* it looks for "/proc/self/exe" _relative to chroot!_ */
execv(bb_busybox_exec_path 1, (char**) argv);
_exit(127);
#endif
}
/* parent */
close(outfd.wr);
#if !BB_MMU
free((char*)argv[2]);
#endif
return outfd.rd;
}
enum {
USE_CTRL_CONN = 1,
LONG_LISTING = 2,
};
static void
handle_dir_common(int opts)
{
FILE *ls_fp;
char *line;
int ls_fd;
if (!(opts & USE_CTRL_CONN) && !port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
/* -n prevents user/groupname display,
* which can be problematic in chroot */
ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1");
ls_fp = xfdopen_for_read(ls_fd);
if (opts & USE_CTRL_CONN) {
/* STAT <filename> */
cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n");
while (1) {
line = xmalloc_fgetline(ls_fp);
if (!line)
break;
/* Hack: 0 results in no status at all */
/* Note: it's ok that we don't prepend space,
* ftp.kernel.org doesn't do that too */
cmdio_write(0, line);
free(line);
}
WRITE_OK(FTP_STATFILE_OK);
} else {
/* LIST/NLST [<filename>] */
int remote_fd = get_remote_transfer_fd(" Directory listing");
if (remote_fd >= 0) {
while (1) {
line = xmalloc_fgetline(ls_fp);
if (!line)
break;
/* I've seen clients complaining when they
* are fed with ls output with bare '\n'.
* Pity... that would be much simpler.
*/
/* TODO: need to s/LF/NUL/g here */
xwrite_str(remote_fd, line);
xwrite(remote_fd, "\r\n", 2);
free(line);
}
}
close(remote_fd);
WRITE_OK(FTP_TRANSFEROK);
}
fclose(ls_fp); /* closes ls_fd too */
}
static void
handle_list(void)
{
handle_dir_common(LONG_LISTING);
}
static void
handle_nlst(void)
{
/* NLST returns list of names, "\r\n" terminated without regard
* to the current binary flag. Names may start with "/",
* then they represent full names (we don't produce such names),
* otherwise names are relative to current directory.
* Embedded "\n" are replaced by NULs. This is safe since names
* can never contain NUL.
*/
handle_dir_common(0);
}
static void
handle_stat_file(void)
{
handle_dir_common(LONG_LISTING USE_CTRL_CONN);
}
/* This can be extended to handle MLST, as all info is available
* in struct stat for that:
* MLST file_name
* 250-Listing file_name
* type=file;size=4161;modify=19970214165800; /dir/dir/file_name
* 250 End
* Nano-doc:
* MLST [<file or dir name, "." assumed if not given>]
* Returned name should be either the same as requested, or fully qualified.
* If there was no parameter, return "" or (preferred) fully-qualified name.
* Returned "facts" (case is not important):
* size - size in octets
* modify - last modification time
* type - entry type (file,dir,OS.unix=block)
* ( cdir and pdir types for MLSD)
* unique - unique id of file/directory (inode#)
* perm -
* a: can be appended to (APPE)
* d: can be deleted (RMD/DELE)
* f: can be renamed (RNFR)
* r: can be read (RETR)
* w: can be written (STOR)
* e: can CWD into this dir
* l: this dir can be listed (dir only!)
* c: can create files in this dir
* m: can create dirs in this dir (MKD)
* p: can delete files in this dir
* UNIX.mode - unix file mode
*/
static void
handle_size_or_mdtm(int need_size)
{
struct stat statbuf;
struct tm broken_out;
char buf[(sizeof("NNN %"OFF_FMT"u\r\n") sizeof(off_t) * 3)
| sizeof("NNN YYYYMMDDhhmmss\r\n")
];
if (!G.ftp_arg
|| stat(G.ftp_arg, &statbuf) != 0
|| !S_ISREG(statbuf.st_mode)
) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
if (need_size) {
sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
} else {
gmtime_r(&statbuf.st_mtime, &broken_out);
sprintf(buf, STR(FTP_STATFILE_OK)" uuuuuu\r\n",
broken_out.tm_year 1900,
broken_out.tm_mon,
broken_out.tm_mday,
broken_out.tm_hour,
broken_out.tm_min,
broken_out.tm_sec);
}
cmdio_write_raw(buf);
}
/* Upload commands */
#if ENABLE_FEATURE_FTP_WRITE
static void
handle_mkd(void)
{
if (!G.ftp_arg || mkdir(G.ftp_arg, 0777) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_MKDIROK);
}
static void
handle_rmd(void)
{
if (!G.ftp_arg || rmdir(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_RMDIROK);
}
static void
handle_dele(void)
{
if (!G.ftp_arg || unlink(G.ftp_arg) != 0) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_DELEOK);
}
static void
handle_rnfr(void)
{
free(G.rnfr_filename);
G.rnfr_filename = xstrdup(G.ftp_arg);
WRITE_OK(FTP_RNFROK);
}
static void
handle_rnto(void)
{
int retval;
/* If we didn't get a RNFR, throw a wobbly */
if (G.rnfr_filename == NULL || G.ftp_arg == NULL) {
cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n");
return;
}
retval = rename(G.rnfr_filename, G.ftp_arg);
free(G.rnfr_filename);
G.rnfr_filename = NULL;
if (retval) {
WRITE_ERR(FTP_FILEFAIL);
return;
}
WRITE_OK(FTP_RENAMEOK);
}
static void
handle_upload_common(int is_append, int is_unique)
{
struct stat statbuf;
char *tempname;
off_t bytes_transferred;
off_t offset;
int local_file_fd;
int remote_fd;
offset = G.restart_pos;
G.restart_pos = 0;
if (!port_or_pasv_was_seen())
return; /* port_or_pasv_was_seen emitted error response */
tempname = NULL;
local_file_fd = -1;
if (is_unique) {
tempname = xstrdup(" FILE: uniq.XXXXXX");
local_file_fd = mkstemp(tempname 7);
} else if (G.ftp_arg) {
int flags = O_WRONLY | O_CREAT | O_TRUNC;
if (is_append)
flags = O_WRONLY | O_CREAT | O_APPEND;
if (offset)
flags = O_WRONLY | O_CREAT;
local_file_fd = open(G.ftp_arg, flags, 0666);
}
if (local_file_fd < 0
|| fstat(local_file_fd, &statbuf) != 0
|| !S_ISREG(statbuf.st_mode)
) {
WRITE_ERR(FTP_UPLOADFAIL);
if (local_file_fd >= 0)
goto close_local_and_bail;
return;
}
G.local_file_fd = local_file_fd;
if (offset)
xlseek(local_file_fd, offset, SEEK_SET);
remote_fd = get_remote_transfer_fd(tempname ? tempname : " Ok to send data");
free(tempname);
if (remote_fd < 0)
goto close_local_and_bail;
bytes_transferred = bb_copyfd_eof(remote_fd, local_file_fd);
close(remote_fd);
if (bytes_transferred < 0)
WRITE_ERR(FTP_BADSENDFILE);
else
WRITE_OK(FTP_TRANSFEROK);
close_local_and_bail:
close(local_file_fd);
G.local_file_fd = 0;
}
static void
handle_stor(void)
{
handle_upload_common(0, 0);
}
static void
handle_appe(void)
{
G.restart_pos = 0;
handle_upload_common(1, 0);
}
static void
handle_stou(void)
{
G.restart_pos = 0;
handle_upload_common(0, 1);
}
#endif /* ENABLE_FEATURE_FTP_WRITE */
static uint32_t
cmdio_get_cmd_and_arg(void)
{
int len;
uint32_t cmdval;
char *cmd;
alarm(G.timeout);
free(G.ftp_cmd);
{
/* Paranoia. Peer may send 1 gigabyte long cmd... */
/* Using separate len_on_stk instead of len optimizes
* code size (allows len to be in CPU register) */
size_t len_on_stk = 8 * 1024;
G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len_on_stk);
if (!cmd)
exit(0);
len = len_on_stk;
}
/* De-escape telnet: 0xff,0xff => 0xff */
/* RFC959 says that ABOR, STAT, QUIT may be sent even during
* data transfer, and may be preceded by telnet's "Interrupt Process"
* code (two-byte sequence 255,244) and then by telnet "Synch" code
* 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
* and may generate SIGURG on our side. See RFC854).
* So far we don't support that (may install SIGURG handler if we'd want to),
* but we need to at least remove 255,xxx pairs. lftp sends those. */
/* Then de-escape FTP: NUL => '\n' */
/* Testing for \xff:
* Create file named '\xff': echo Hello >`echo -ne "\xff"`
* Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
* (need "\xff\xff" until ftpget applet is fixed to do escaping :)
* Testing for embedded LF:
* LF_HERE=`echo -ne "LF\nHERE"`
* echo Hello >"$LF_HERE"
* ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
*/
{
int dst, src;
/* Strip "\r\n" if it is there */
if (len != 0 && cmd[len - 1] == '\n') {
len--;
if (len != 0 && cmd[len - 1] == '\r')
len--;
cmd[len] = '\0';
}
src = strchrnul(cmd, 0xff) - cmd;
/* 99,99% there are neither NULs nor 255s and src == len */
if (src < len) {
dst = src;
do {
if ((unsigned char)(cmd[src]) == 255) {
src ;
/* 255,xxx - skip 255 */
if ((unsigned char)(cmd[src]) != 255) {
/* 255,!255 - skip both */
src ;
continue;
}
/* 255,255 - retain one 255 */
}
/* NUL => '\n' */
cmd[dst ] = cmd[src] ? cmd[src] : '\n';
src ;
} while (src < len);
cmd[dst] = '\0';
}
}
if (G.verbose > 1)
verbose_log(cmd);
G.ftp_arg = strchr(cmd, ' ');
if (G.ftp_arg != NULL)
*G.ftp_arg = '\0';
/* Uppercase and pack into uint32_t first word of the command */
cmdval = 0;
while (*cmd)
cmdval = (cmdval << 8) ((unsigned char)*cmd & (unsigned char)~0x20);
return cmdval;
}
#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)
enum {
const_ALLO = mk_const4('A', 'L', 'L', 'O'),
const_APPE = mk_const4('A', 'P', 'P', 'E'),
const_CDUP = mk_const4('C', 'D', 'U', 'P'),
const_CWD = mk_const3('C', 'W', 'D'),
const_DELE = mk_const4('D', 'E', 'L', 'E'),
const_EPSV = mk_const4('E', 'P', 'S', 'V'),
const_FEAT = mk_const4('F', 'E', 'A', 'T'),
const_HELP = mk_const4('H', 'E', 'L', 'P'),
const_LIST = mk_const4('L', 'I', 'S', 'T'),
const_MDTM = mk_const4('M', 'D', 'T', 'M'),
const_MKD = mk_const3('M', 'K', 'D'),
const_MODE = mk_const4('M', 'O', 'D', 'E'),
const_NLST = mk_const4('N', 'L', 'S', 'T'),
const_NOOP = mk_const4('N', 'O', 'O', 'P'),
const_PASS = mk_const4('P', 'A', 'S', 'S'),
const_PASV = mk_const4('P', 'A', 'S', 'V'),
const_PORT = mk_const4('P', 'O', 'R', 'T'),
const_PWD = mk_const3('P', 'W', 'D'),
const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
const_REST = mk_const4('R', 'E', 'S', 'T'),
const_RETR = mk_const4('R', 'E', 'T', 'R'),
const_RMD = mk_const3('R', 'M', 'D'),
const_RNFR = mk_const4('R', 'N', 'F', 'R'),
const_RNTO = mk_const4('R', 'N', 'T', 'O'),
const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
const_STAT = mk_const4('S', 'T', 'A', 'T'),
const_STOR = mk_const4('S', 'T', 'O', 'R'),
const_STOU = mk_const4('S', 'T', 'O', 'U'),
const_STRU = mk_const4('S', 'T', 'R', 'U'),
const_SYST = mk_const4('S', 'Y', 'S', 'T'),
const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
const_USER = mk_const4('U', 'S', 'E', 'R'),
#if !BB_MMU
OPT_l = (1 << 0),
OPT_1 = (1 << 1),
#endif
OPT_v = (1 << ((!BB_MMU) * 2 0)),
OPT_S = (1 << ((!BB_MMU) * 2 1)),
OPT_w = (1 << ((!BB_MMU) * 2 2)) * ENABLE_FEATURE_FTP_WRITE,
};
//wsm add
#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
static int parse_username(char *user_list,char *user)//该函数是用来验证用户名的
{
FILE *stream;
char buf[100];
bzero(buf,sizeof(buf));
if((stream = fopen(user_list,"r"))==NULL)
{
//puts("file /etc/ftpusers open fail! \n");
return 0;
}
while ((fgets (buf, 100, stream)) != NULL)
{
buf[strlen(buf)-1]='\0';
if((buf[0]!='#')&&(strcmp(buf,user)==0))
{
//puts("user is accept !\n");
fclose(stream);
return 1;
}
}
fclose(stream);
//puts("user is refuse !\n");
return 0;
}
static int parse_username_password(char *user,char *password)//该函数是用来验证用户名对应的密码的
{
const char *cpwd = NULL;
struct passwd *pw;
struct spwd *spw;
char *crypt_pw;
pw=getpwnam(user);
if(pw)
{
if ((((pw->pw_passwd)[0] == 'x' && (pw->pw_passwd)[1] == 0) || \
((pw->pw_passwd)[0] == '#' && (pw->pw_passwd)[1] == '#' && \
strcmp(pw->pw_passwd 2, user) == 0)) && \
(spw = getspnam(user)) != NULL && spw->sp_pwdp != NULL)
{
cpwd = spw->sp_pwdp[0] == '@' ? NULL : spw->sp_pwdp;
}
else
{
cpwd= pw->pw_passwd;
}
crypt_pw = crypt(password,cpwd);
if (strcmp(cpwd,crypt_pw)==0)
{
//printf("Success!\n");
return 1;
}
else
{
//printf("Password is not correct!\n");
return 0;
}
}
else
{
//printf("Unknown User!\n");
return 0;
}
}
#endif
//end wsm
int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
#if !BB_MMU
int ftpd_main(int argc, char **argv)
#else
int ftpd_main(int argc UNUSED_PARAM, char **argv)
#endif
{
unsigned abs_timeout;
unsigned verbose_S;
smallint opts;
char user[50];//wsm add
char user_list[50]="/etc/ftpusers";//wsm add
INIT_G();
abs_timeout = 1 * 60 * 60;
verbose_S = 0;
G.timeout = 2 * 60;
opt_complementary = "t :T :vv:SS";
#if BB_MMU
opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
#else
opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
if (opts & (OPT_l|OPT_1)) {
/* Our secret backdoor to ls */
/* TODO: pass -n? It prevents user/group resolution, which may not work in chroot anyway */
/* TODO: pass -A? It shows dot files */
/* TODO: pass --group-directories-first? would be nice, but ls doesn't do that yet */
xchdir(argv[2]);
argv[2] = (char*)"--";
/* memset(&G, 0, sizeof(G)); - ls_main does it */
return ls_main(argc, argv);
}
#endif
if (G.verbose < verbose_S)
G.verbose = verbose_S;
if (abs_timeout | G.timeout) {
if (abs_timeout == 0)
abs_timeout = INT_MAX;
G.end_time = monotonic_sec() abs_timeout;
if (G.timeout > abs_timeout)
G.timeout = abs_timeout;
}
strcpy(G.msg_ok 4, MSG_OK );
strcpy(G.msg_err 4, MSG_ERR);
G.local_addr = get_sock_lsa(STDIN_FILENO);
if (!G.local_addr) {
/* This is confusing:
* bb_error_msg_and_die("stdin is not a socket");
* Better: */
bb_show_usage();
/* Help text says that ftpd must be used as inetd service,
* which is by far the most usual cause of get_sock_lsa
* failure */
}
if (!(opts & OPT_v))
logmode = LOGMODE_NONE;
if (opts & OPT_S) {
/* LOG_NDELAY is needed since we may chroot later */
openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
logmode |= LOGMODE_SYSLOG;
}
if (logmode)
applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
#if !BB_MMU
G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
close_on_exec_on(G.root_fd);
#endif
if (argv[optind]) {
xchdir(argv[optind]);
chroot(".");
}
//wsm add 该段代码是用来读取出被允许的用户列表文件的路径，只有在该列表中的用户才被允许登陆
if(argv[optind 1])
{
strcpy(user_list,argv[optind 1]);
}
//end wsm
//umask(077); - admin can set umask before starting us
/* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
signal(SIGPIPE, SIG_IGN);
/* Set up options on the command socket (do we need these all? why?) */
setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
/* Telnet protocol over command link may send "urgent" data,
* we prefer it to be received in the "normal" data stream: */
setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
WRITE_OK(FTP_GREET);
signal(SIGALRM, timeout_handler);
#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
{
smallint user_was_specified = 0;
while (1) {
uint32_t cmdval = cmdio_get_cmd_and_arg();
if (cmdval == const_USER) {
//if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)//wsm dec
if (G.ftp_arg == NULL || parse_username(user_list,G.ftp_arg) == 0)//wsm
cmdio_write_raw(STR(FTP_LOGINERR)" user is refuse\r\n");//wsm ch
else {
user_was_specified = 1;
strcpy(user,G.ftp_arg);
cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
}
} else if (cmdval == const_PASS) {
if (user_was_specified)
{
if(parse_username_password(user,G.ftp_arg))
{
break;
}
cmdio_write_raw(STR(FTP_LOGINERR)" password error\r\n");
}
else
{
cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
}
} else if (cmdval == const_QUIT) {
WRITE_OK(FTP_GOODBYE);
return 0;
} else {
cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
}
}
}
WRITE_OK(FTP_LOGINOK);
#endif
/* RFC-959 Section 5.1
* The following commands and options MUST be supported by every
* server-FTP and user-FTP, except in cases where the underlying
* file system or operating system does not allow or support
* a particular command.
* Type: ASCII Non-print, IMAGE, LOCAL 8
* Mode: Stream
* Structure: File, Record*
* (Record structure is REQUIRED only for hosts whose file
* systems support record structure).
* Commands:
* USER, PASS, ACCT, [bbox: ACCT not supported]
* PORT, PASV,
* TYPE, MODE, STRU,
* RETR, STOR, APPE,
* RNFR, RNTO, DELE,
* CWD, CDUP, RMD, MKD, PWD,
* LIST, NLST,
* SYST, STAT,
* HELP, NOOP, QUIT.
*/
/* ACCOUNT (ACCT)
* "The argument field is a Telnet string identifying the user's account.
* The command is not necessarily related to the USER command, as some
* sites may require an account for login and others only for specific
* access, such as storing files. In the latter case the command may
* arrive at any time.
* There are reply codes to differentiate these cases for the automation:
* when account information is required for login, the response to
* a successful PASSword command is reply code 332. On the other hand,
* if account information is NOT required for login, the reply to
* a successful PASSword command is 230; and if the account information
* is needed for a command issued later in the dialogue, the server
* should return a 332 or 532 reply depending on whether it stores
* (pending receipt of the ACCounT command) or discards the command,
* respectively."
*/
while (1) {
uint32_t cmdval = cmdio_get_cmd_and_arg();
if (cmdval == const_QUIT) {
WRITE_OK(FTP_GOODBYE);
return 0;
}
else if (cmdval == const_USER)
/* This would mean "ok, now give me PASS". */
/*WRITE_OK(FTP_GIVEPWORD);*/
/* vsftpd can be configured to not require that,
* and this also saves one roundtrip:
*/
WRITE_OK(FTP_LOGINOK);
else if (cmdval == const_PASS)
WRITE_OK(FTP_LOGINOK);
else if (cmdval == const_NOOP)
WRITE_OK(FTP_NOOPOK);
else if (cmdval == const_TYPE)
WRITE_OK(FTP_TYPEOK);
else if (cmdval == const_STRU)
WRITE_OK(FTP_STRUOK);
else if (cmdval == const_MODE)
WRITE_OK(FTP_MODEOK);
else if (cmdval == const_ALLO)
WRITE_OK(FTP_ALLOOK);
else if (cmdval == const_SYST)
cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
else if (cmdval == const_PWD)
handle_pwd();
else if (cmdval == const_CWD)
handle_cwd();
else if (cmdval == const_CDUP) /* cd .. */
handle_cdup();
/* HELP is nearly useless, but we can reuse FEAT for it */
/* lftp uses FEAT */
else if (cmdval == const_HELP || cmdval == const_FEAT)
handle_feat(cmdval == const_HELP
? STRNUM32(FTP_HELP)
: STRNUM32(FTP_STATOK)
);
else if (cmdval == const_LIST) /* ls -l */
handle_list();
else if (cmdval == const_NLST) /* "name list", bare ls */
handle_nlst();
/* SIZE is crucial for wget's download indicator etc */
/* Mozilla, lftp use MDTM (presumably for caching) */
else if (cmdval == const_SIZE || cmdval == const_MDTM)
handle_size_or_mdtm(cmdval == const_SIZE);
else if (cmdval == const_STAT) {
if (G.ftp_arg == NULL)
handle_stat();
else
handle_stat_file();
}
else if (cmdval == const_PASV)
handle_pasv();
else if (cmdval == const_EPSV)
handle_epsv();
else if (cmdval == const_RETR)
handle_retr();
else if (cmdval == const_PORT)
handle_port();
else if (cmdval == const_REST)
handle_rest();
#if ENABLE_FEATURE_FTP_WRITE
else if (opts & OPT_w) {
if (cmdval == const_STOR)
handle_stor();
else if (cmdval == const_MKD)
handle_mkd();
else if (cmdval == const_RMD)
handle_rmd();
else if (cmdval == const_DELE)
handle_dele();
else if (cmdval == const_RNFR) /* "rename from" */
handle_rnfr();
else if (cmdval == const_RNTO) /* "rename to" */
handle_rnto();
else if (cmdval == const_APPE)
handle_appe();
else if (cmdval == const_STOU) /* "store unique" */
handle_stou();
else
goto bad_cmd;
}
#endif
#if 0
else if (cmdval == const_STOR
|| cmdval == const_MKD
|| cmdval == const_RMD
|| cmdval == const_DELE
|| cmdval == const_RNFR
|| cmdval == const_RNTO
|| cmdval == const_APPE
|| cmdval == const_STOU
) {
cmdio_write_raw(STR(FTP_NOPERM)" Permission denied\r\n");
}
#endif
else {
/* Which unsupported commands were seen in the wild?
* (doesn't necessarily mean "we must support them")
* foo 1.2.3: XXXX - comment
*/
#if ENABLE_FEATURE_FTP_WRITE
bad_cmd:
#endif
cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");
}
}
}
tcpsvd 0 21 ftpd -w / -t 5 /etc/ftpusers
上面是我的启动ftpd服务器的命令
第一个‘/’是ftpd服务器的共享目录，“/etc/ftpusers”是被允许的用户列表文件，用户可以根据实际路径改变，用户列表文件的格式为每一行一个用户名，不允许的用户删除该行或者用#注释掉即可，另外要求用户列表文件路径必须在共享目录路径的后面。
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
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- http://blog.chinaunix.net/uid-26335251-id-3508651.html
- fork()与vfork()的区别 http://blog.chinaunix.net/uid-18921523-id-265538.html
- 高性能网络I/O框架-netmap源码分析(5) http://blog.chinaunix.net/uid-23629988-id-3693204.html
- http://blog.chinaunix.net/uid-25547034-id-3155778.html
- http://blog.chinaunix.net/uid-25835268-id-3055356.html--makefile
- 教你透彻了解红黑树 http://blog.chinaunix.net/uid-26575352-id-3061918.html
- fcntl与文件锁 2013-11-25 15:45:55 http://blog.chinaunix.net/uid-20775448-id-4009263.html
- Linux内核中流量控制 http://blog.chinaunix.net/uid-127037-id-2919583.html
- curl 转自 http://blog.chinaunix.net/uid-22655387-id-3283161.html
- zookeeper基本原理及适用场景 转：http://blog.chinaunix.net/uid-26748613-id-4536290.html
- 移植自己的printf，scanf函数（引用：http://blog.chinaunix.net/uid-18921523-id-187419.html）
- http://blog.chinaunix.net/uid-21222282-id-3244532.html
- 虚函数及继承 http://blog.chinaunix.net/uid-25132162-id-1564955.html
- 内核线程 http://blog.chinaunix.net/uid-24467128-id-3246495.html
- TCP/IP源码学习(47)——socket与VFS的关联(1) 2 http://blog.chinaunix.net/uid-23629988-id-3080166.html
- 结构体赋值及free()的问题 2010-10-27 12:42:15 http://blog.chinaunix.net/uid-21702630-id-205956.html