/*

* getpass.c - platform independent getpass function.

*

* This file is part of the SSH Library

*

* Copyright (c) 2011-2013 by Andreas Schneider <mail@cryptomilk.org>

*

* The SSH Library is free software; you can redistribute it and/or modify

* it under the terms of the GNU Lesser General Public License as published by

* the Free Software Foundation; either version 2.1 of the License, or (at your

* option) any later version.

*

* The SSH Library is distributed in the hope that it will be useful, but

* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public

* License for more details.

*

* You should have received a copy of the GNU Lesser General Public License

* along with the SSH Library; see the file COPYING. If not, write to

* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

* MA 02111-1307, USA.

*/

#include "config.h"

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <libssh/priv.h>

/**

* @internal

*

* @brief Get the password from the console.

*

* @param[in] prompt The prompt to display.

*

* @param[in] buf The buffer to fill.

*

* @param[in] len The length of the buffer.

*

* @param[in] verify Should the password be verified?

*

* @return 1 on success, 0 on error.

*/

static int ssh_gets(const char *prompt, char *buf, size_t len, int verify) {

char *tmp;

char *ptr = NULL;

int ok = 0;

tmp = calloc(1, len);

if (tmp == NULL) {

return 0;

}

/* read the password */

while (!ok) {

if (buf[0] != '\0') {

fprintf(stdout, "%s[%s] ", prompt, buf);

} else {

fprintf(stdout, "%s", prompt);

}

fflush(stdout);

if (fgets(tmp, len, stdin) == NULL) {

free(tmp);

return 0;

}

if ((ptr = strchr(tmp, '\n'))) {

*ptr = '\0';

}

fprintf(stdout, "\n");

if (*tmp) {

strncpy(buf, tmp, len);

}

if (verify) {

char *key_string;

key_string = calloc(1, len);

if (key_string == NULL) {

break;

}

fprintf(stdout, "\nVerifying, please re-enter. %s", prompt);

fflush(stdout);

if (! fgets(key_string, len, stdin)) {

explicit_bzero(key_string, len);

SAFE_FREE(key_string);

clearerr(stdin);

continue;

}

if ((ptr = strchr(key_string, '\n'))) {

*ptr = '\0';

}

fprintf(stdout, "\n");

if (strcmp(buf, key_string)) {

printf("\n\07\07Mismatch - try again\n");

explicit_bzero(key_string, len);

SAFE_FREE(key_string);

fflush(stdout);

continue;

}

explicit_bzero(key_string, len);

SAFE_FREE(key_string);

}

ok = 1;

}

explicit_bzero(tmp, len);

free(tmp);

return ok;

}

#ifdef _WIN32

#include <windows.h>

int ssh_getpass(const char *prompt,

char *buf,

size_t len,

int echo,

int verify) {

HANDLE h;

DWORD mode = 0;

int ok;

/* fgets needs at least len - 1 */

if (prompt == NULL || buf == NULL || len < 2) {

return -1;

}

/* get stdin and mode */

h = GetStdHandle(STD_INPUT_HANDLE);

if (!GetConsoleMode(h, &mode)) {

return -1;

}

/* disable echo */

if (!echo) {

if (!SetConsoleMode(h, mode & ~ENABLE_ECHO_INPUT)) {

return -1;

}

}

ok = ssh_gets(prompt, buf, len, verify);

/* reset echo */

SetConsoleMode(h, mode);

if (!ok) {

explicit_bzero(buf, len);

return -1;

}

/* force termination */

buf[len - 1] = '\0';

return 0;

}

#else

#include <fcntl.h>

#ifdef HAVE_TERMIOS_H

#include <termios.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

/**

* @ingroup libssh_misc

*

* @brief Get a password from the console.

*

* You should make sure that the buffer is an empty string!

*

* You can also use this function to ask for a username. Then you can fill the

* buffer with the username and it is shows to the users. If the users just

* presses enter the buffer will be untouched.

*

* @code

* char username[128];

*

* snprintf(username, sizeof(username), "john");

*

* ssh_getpass("Username:", username, sizeof(username), 1, 0);

* @endcode

*

* The prompt will look like this:

*

* Username: [john]

*

* If you press enter then john is used as the username, or you can type it in

* to change it.

*

* @param[in] prompt The prompt to show to ask for the password.

*

* @param[out] buf The buffer the password should be stored. It NEEDS to be

* empty or filled out.

*

* @param[in] len The length of the buffer.

*

* @param[in] echo Should we echo what you type.

*

* @param[in] verify Should we ask for the password twice.

*

* @return 0 on success, -1 on error.

*/

int ssh_getpass(const char *prompt,

char *buf,

size_t len,

int echo,

int verify) {

struct termios attr;

struct termios old_attr;

int ok = 0;

int fd = -1;

/* fgets needs at least len - 1 */

if (prompt == NULL || buf == NULL || len < 2) {

return -1;

}

if (isatty(STDIN_FILENO)) {

ZERO_STRUCT(attr);

ZERO_STRUCT(old_attr);

/* get local terminal attributes */

if (tcgetattr(STDIN_FILENO, &attr) < 0) {

perror("tcgetattr");

return -1;

}

/* save terminal attributes */

memcpy(&old_attr, &attr, sizeof(attr));

if((fd = fcntl(0, F_GETFL, 0)) < 0) {

perror("fcntl");

return -1;

}

/* disable echo */

if (!echo) {

attr.c_lflag &= ~(ECHO);

}

/* write attributes to terminal */

if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &attr) < 0) {

perror("tcsetattr");

return -1;

}

}

/* disable nonblocking I/O */

if (fd & O_NDELAY) {

ok = fcntl(0, F_SETFL, fd & ~O_NDELAY);

if (ok < 0) {

perror("fcntl");

return -1;

}

}

ok = ssh_gets(prompt, buf, len, verify);

if (isatty(STDIN_FILENO)) {

/* reset terminal */

tcsetattr(STDIN_FILENO, TCSANOW, &old_attr);

}

/* close fd */

if (fd & O_NDELAY) {

ok = fcntl(0, F_SETFL, fd);

if (ok < 0) {

perror("fcntl");

return -1;

}

}

if (!ok) {

explicit_bzero(buf, len);

return -1;

}

/* force termination */

buf[len - 1] = '\0';

return 0;

}

#endif