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ftpd: add optional support for authentication

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function                                             old     new   delta
cmdio_get_cmd_and_arg                                  -     237    +237
get_passwd                                             -      97     +97
check_password                                         -      82     +82
ftpd_main                                           2297    2178    -119
ask_and_check_password_extended                      206      84    -122
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 0/2 up/down: 416/-241)          Total: 175 bytes

Signed-off-by: Morten Kvistgaard <MK@pch-engineering.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Morten Kvistgaard 2014-08-05 21:57:18 +02:00 committed by Denys Vlasenko
parent 09a0e2223f
commit feac9b607d
5 changed files with 100 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/libbb.h
View File

@ -1316,6 +1316,7 @@ int sd_listen_fds(void);
#define SETUP_ENV_NO_CHDIR (1 << 4)
void setup_environment(const char *shell, int flags, const struct passwd *pw) FAST_FUNC;
void nuke_str(char *str) FAST_FUNC;
int check_password(const struct passwd *pw, const char *plaintext) FAST_FUNC;
int ask_and_check_password_extended(const struct passwd *pw, int timeout, const char *prompt) FAST_FUNC;
int ask_and_check_password(const struct passwd *pw) FAST_FUNC;
/* Returns a malloced string */

1
libbb/Kbuild.src
View File

@ -150,6 +150,7 @@ lib-$(CONFIG_VLOCK) += pw_encrypt.o correct_password.o
lib-$(CONFIG_SU) += pw_encrypt.o correct_password.o
lib-$(CONFIG_LOGIN) += pw_encrypt.o correct_password.o
lib-$(CONFIG_FEATURE_HTTPD_AUTH_MD5) += pw_encrypt.o
lib-$(CONFIG_FEATURE_FTP_AUTHENTICATION) += pw_encrypt.o
lib-$(CONFIG_DF) += find_mount_point.o
lib-$(CONFIG_MKFS_MINIX) += find_mount_point.o

96
libbb/correct_password.c
View File

@ -30,6 +30,63 @@
#include "libbb.h"
#define SHADOW_BUFSIZE 256
/* Retrieve encrypted password string for pw.
* If pw == NULL, return a string which fails password check against any
* password.
*/
#if !ENABLE_FEATURE_SHADOWPASSWDS
#define get_passwd(pw, buffer) get_passwd(pw)
#endif
static const char *get_passwd(const struct passwd *pw, char buffer[SHADOW_BUFSIZE])
{
const char *pass;
if (!pw)
return "aa"; /* "aa" will never match */
pass = pw->pw_passwd;
#if ENABLE_FEATURE_SHADOWPASSWDS
/* Using _r function to avoid pulling in static buffers */
if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
struct spwd spw;
int r;
/* getspnam_r may return 0 yet set result to NULL.
* At least glibc 2.4 does this. Be extra paranoid here. */
struct spwd *result = NULL;
r = getspnam_r(pw->pw_name, &spw, buffer, SHADOW_BUFSIZE, &result);
pass = (r || !result) ? "aa" : result->sp_pwdp;
}
#endif
return pass;
}
/*
* Return 1 if PW has an empty password.
* Return 1 if the user gives the correct password for entry PW,
* 0 if not.
* NULL pw means "just fake it for login with bad username"
*/
int FAST_FUNC check_password(const struct passwd *pw, const char *plaintext)
{
IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
char *encrypted;
const char *pw_pass;
int r;
pw_pass = get_passwd(pw, buffer);
if (!pw_pass[0]) { /* empty password field? */
return 1;
}
encrypted = pw_encrypt(plaintext, /*salt:*/ pw_pass, 1);
r = (strcmp(encrypted, pw_pass) == 0);
free(encrypted);
return r;
}
/* Ask the user for a password.
* Return 1 without asking if PW has an empty password.
* Return -1 on EOF, error while reading input, or timeout.
@ -41,42 +98,23 @@
int FAST_FUNC ask_and_check_password_extended(const struct passwd *pw,
int timeout, const char *prompt)
{
char *unencrypted, *encrypted;
const char *correct;
IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
char *plaintext;
const char *pw_pass;
int r;
/* fake salt. crypt() can choke otherwise. */
correct = "aa";
if (!pw) {
/* "aa" will never match */
goto fake_it;
}
correct = pw->pw_passwd;
#if ENABLE_FEATURE_SHADOWPASSWDS
/* Using _r function to avoid pulling in static buffers */
if ((correct[0] == 'x' || correct[0] == '*') && !correct[1]) {
struct spwd spw;
char buffer[256];
/* getspnam_r may return 0 yet set result to NULL.
* At least glibc 2.4 does this. Be extra paranoid here. */
struct spwd *result = NULL;
r = getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result);
correct = (r || !result) ? "aa" : result->sp_pwdp;
}
#endif
if (!correct[0]) /* empty password field? */
pw_pass = get_passwd(pw, buffer);
if (!pw_pass[0]) /* empty password field? */
return 1;
fake_it:
unencrypted = bb_ask(STDIN_FILENO, timeout, prompt);
if (!unencrypted) {
plaintext = bb_ask(STDIN_FILENO, timeout, prompt);
if (!plaintext) {
/* EOF (such as ^D) or error (such as ^C) or timeout */
return -1;
}
encrypted = pw_encrypt(unencrypted, correct, 1);
r = (strcmp(encrypted, correct) == 0);
free(encrypted);
nuke_str(unencrypted);
r = check_password(pw, plaintext);
nuke_str(plaintext);
return r;
}

7
networking/Config.src
View File

@ -134,6 +134,13 @@ config FEATURE_FTPD_ACCEPT_BROKEN_LIST
it increases the code size by ~40 bytes.
Most other ftp servers seem to behave similar to this.
config FEATURE_FTP_AUTHENTICATION
bool "Enable authentication"
default y
depends on FTPD
help
Enable basic system login as seen in telnet etc.
config FTPGET
bool "ftpget"
default y

47
networking/ftpd.c
View File

@ -1172,18 +1172,6 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
if (logmode)
applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
#if !BB_MMU
G.root_fd = -1;
#endif
argv += optind;
if (argv[0]) {
#if !BB_MMU
G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
close_on_exec_on(G.root_fd);
#endif
xchroot(argv[0]);
}
//umask(077); - admin can set umask before starting us
/* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
@ -1199,23 +1187,22 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
WRITE_OK(FTP_GREET);
signal(SIGALRM, timeout_handler);
#ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
#if ENABLE_FEATURE_FTP_AUTHENTICATION
{
smallint user_was_specified = 0;
struct passwd *pw = NULL;
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)
cmdio_write_raw(STR(FTP_LOGINERR)" Server is anonymous only\r\n");
else {
user_was_specified = 1;
cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
}
pw = getpwnam(G.ftp_arg);
cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify password\r\n");
} else if (cmdval == const_PASS) {
if (user_was_specified)
break;
cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
if (check_password(pw, G.ftp_arg) > 0) {
break; /* login success */
}
cmdio_write_raw(STR(FTP_LOGINERR)" Login failed\r\n");
pw = NULL;
} else if (cmdval == const_QUIT) {
WRITE_OK(FTP_GOODBYE);
return 0;
@ -1223,10 +1210,24 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
}
}
change_identity(pw);
}
WRITE_OK(FTP_LOGINOK);
#endif
/* Do this after auth, else /etc/passwd is not accessible */
#if !BB_MMU
G.root_fd = -1;
#endif
argv += optind;
if (argv[0]) {
#if !BB_MMU
G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
close_on_exec_on(G.root_fd);
#endif
xchroot(argv[0]);
}
/* 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