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feac9b607

Morten Kvistgaard
Morten Kvistgaard
2014-08-05
SUCCESS Duration: 152s

Subject

ftpd: add optional support for authentication

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

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Commit Diff GitHub →

include/libbb.h +1 -0libbb/Kbuild.src +1 -0libbb/correct_password.c +67 -29networking/Config.src +7 -0networking/ftpd.c +24 -23
include/libbb.h+1 -0
@@ -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 */
libbb/Kbuild.src+1 -0
@@ -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
libbb/correct_password.c+67 -29
@@ -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;
}
networking/Config.src+7 -0
@@ -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
networking/ftpd.c+24 -23
@@ -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