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wget: add EPSV support

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function                                             old     new   delta
parse_pasv_epsv                                        -     151    +151
wget_main                                           2440    2382     -58
xconnect_ftpdata                                     223      94    -129
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 0/2 up/down: 151/-187)          Total: -36 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-02-06 15:48:12 +01:00
parent 403f2999f9
commit 1783ffa990
4 changed files with 82 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/libbb.h
View File

@ -787,6 +787,7 @@ ssize_t recv_from_to(int fd, void *buf, size_t len, int flags,
socklen_t sa_size) FAST_FUNC;
uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC;
int parse_pasv_epsv(char *buf) FAST_FUNC;
/* 0 if argv[0] is NULL: */
unsigned string_array_len(char **argv) FAST_FUNC;

57
networking/ftpgetput.c
View File

@ -152,57 +152,16 @@ static void ftp_login(void)
static int xconnect_ftpdata(void)
{
char *buf_ptr;
unsigned port_num;
int port_num;
/*
PASV command will not work for IPv6. RFC2428 describes
IPv6-capable "extended PASV" - EPSV.
"EPSV [protocol]" asks server to bind to and listen on a data port
in specified protocol. Protocol is 1 for IPv4, 2 for IPv6.
If not specified, defaults to "same as used for control connection".
If server understood you, it should answer "229 <some text>(|||port|)"
where "|" are literal pipe chars and "port" is ASCII decimal port#.
There is also an IPv6-capable replacement for PORT (EPRT),
but we don't need that.
NB: PASV may still work for some servers even over IPv6.
For example, vsftp happily answers
"227 Entering Passive Mode (0,0,0,0,n,n)" and proceeds as usual.
*/
if (!ENABLE_FEATURE_IPV6
|| ftpcmd("EPSV", NULL) != 229
) {
/* maybe also go straight to PAST if lsa->u.sa.sa_family == AF_INET? */
if (ftpcmd("PASV", NULL) != 227) {
ftp_die("PASV");
}
/* Response is "NNN garbageN1,N2,N3,N4,P1,P2[)garbage]"
* Server's IP is N1.N2.N3.N4 (we ignore it)
* Server's port for data connection is P1*256+P2 */
buf_ptr = strrchr(buf, ')');
if (buf_ptr) *buf_ptr = '\0';
buf_ptr = strrchr(buf, ',');
*buf_ptr = '\0';
port_num = xatoul_range(buf_ptr + 1, 0, 255);
buf_ptr = strrchr(buf, ',');
*buf_ptr = '\0';
port_num += xatoul_range(buf_ptr + 1, 0, 255) * 256;
} else {
/* Response is "NNN garbage(|||P1|)"
* Server's port for data connection is P1 */
buf_ptr = strrchr(buf, '|');
if (buf_ptr) *buf_ptr = '\0';
buf_ptr = strrchr(buf, '|');
*buf_ptr = '\0';
port_num = xatoul_range(buf_ptr + 1, 0, 65535);
if (ENABLE_FEATURE_IPV6 && ftpcmd("EPSV", NULL) == 229) {
/* good */
} else if (ftpcmd("PASV", NULL) != 227) {
ftp_die("PASV");
}
port_num = parse_pasv_epsv(buf);
if (port_num < 0)
ftp_die("PASV");
set_nport(&lsa->u.sa, htons(port_num));
return xconnect_stream(lsa);

66
networking/parse_pasv_epsv.c Normal file
View File

@ -0,0 +1,66 @@
/*
* Utility routines.
*
* Copyright (C) 2018 Denys Vlasenko
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//kbuild:lib-$(CONFIG_FTPGET) += ftpgetput.o
//kbuild:lib-$(CONFIG_FTPPUT) += ftpgetput.o
//kbuild:lib-$(CONFIG_WGET) += parse_pasv_epsv.o
#include "libbb.h"
int FAST_FUNC parse_pasv_epsv(char *buf)
{
/*
* PASV command will not work for IPv6. RFC2428 describes
* IPv6-capable "extended PASV" - EPSV.
*
* "EPSV [protocol]" asks server to bind to and listen on a data port
* in specified protocol. Protocol is 1 for IPv4, 2 for IPv6.
* If not specified, defaults to "same as used for control connection".
* If server understood you, it should answer "229 <some text>(|||port|)"
* where "|" are literal pipe chars and "port" is ASCII decimal port#.
*
* There is also an IPv6-capable replacement for PORT (EPRT),
* but we don't need that.
*
* NB: PASV may still work for some servers even over IPv6.
* For example, vsftp happily answers
* "227 Entering Passive Mode (0,0,0,0,n,n)" and proceeds as usual.
*/
char *ptr;
int port;
if (!ENABLE_FEATURE_IPV6 || buf[2] == '7' /* "227" */) {
/* Response is "227 garbageN1,N2,N3,N4,P1,P2[)garbage]"
* Server's IP is N1.N2.N3.N4 (we ignore it)
* Server's port for data connection is P1*256+P2 */
ptr = strrchr(buf, ')');
if (ptr) *ptr = '\0';
ptr = strrchr(buf, ',');
if (!ptr) return -1;
*ptr = '\0';
port = xatou_range(ptr + 1, 0, 255);
ptr = strrchr(buf, ',');
if (!ptr) return -1;
*ptr = '\0';
port += xatou_range(ptr + 1, 0, 255) * 256;
} else {
/* Response is "229 garbage(|||P1|)"
* Server's port for data connection is P1 */
ptr = strrchr(buf, '|');
if (!ptr) return -1;
*ptr = '\0';
ptr = strrchr(buf, '|');
if (!ptr) return -1;
*ptr = '\0';
port = xatou_range(ptr + 1, 0, 65535);
}
return port;
}

19
networking/wget.c
View File

@ -791,22 +791,17 @@ static FILE* prepare_ftp_session(FILE **dfpp, struct host_info *target, len_and_
/*
* Entering passive mode
*/
if (ENABLE_FEATURE_IPV6 && ftpcmd("EPSV", NULL, sfp) == 229) {
/* good */
} else
if (ftpcmd("PASV", NULL, sfp) != 227) {
pasv_error:
bb_error_msg_and_die("bad response to %s: %s", "PASV", sanitize_string(G.wget_buf));
}
// Response is "227 garbageN1,N2,N3,N4,P1,P2[)garbage]
// Server's IP is N1.N2.N3.N4 (we ignore it)
// Server's port for data connection is P1*256+P2
str = strrchr(G.wget_buf, ')');
if (str) str[0] = '\0';
str = strrchr(G.wget_buf, ',');
if (!str) goto pasv_error;
port = xatou_range(str+1, 0, 255);
*str = '\0';
str = strrchr(G.wget_buf, ',');
if (!str) goto pasv_error;
port += xatou_range(str+1, 0, 255) * 256;
port = parse_pasv_epsv(G.wget_buf);
if (port < 0)
goto pasv_error;
set_nport(&lsa->u.sa, htons(port));
*dfpp = open_socket(lsa);