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/* pinentry-tty.c - A minimalist dumb terminal mechanism for PIN entry
* Copyright (C) 2014 Serge Voilokov
* Copyright (C) 2015 Daniel Kahn Gillmor <dkg@fifthhorseman.net>
* Copyright (C) 2015 g10 Code GmbH
*
* This file is part of PINENTRY.
*
* PINENTRY is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* PINENTRY 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: GPL-2.0+
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <signal.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <termios.h>
#ifdef HAVE_UTIME_H
#include <utime.h>
#endif /*HAVE_UTIME_H*/
#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
#include <gpg-error.h>
#include "pinentry.h"
#include "memory.h"
#ifndef HAVE_DOSISH_SYSTEM
static int timed_out;
#endif
static struct termios n_term;
static struct termios o_term;
static int
terminal_save (int fd)
{
if ((tcgetattr (fd, &o_term)) == -1)
return -1;
return 0;
}
static void
terminal_restore (int fd)
{
tcsetattr (fd, TCSANOW, &o_term);
}
static int
terminal_setup (int fd, int line_edit)
{
n_term = o_term;
if (line_edit)
n_term.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
else
{
n_term.c_lflag &= ~(ECHO|ICANON);
n_term.c_lflag |= ISIG;
n_term.c_cc[VMIN] = 1;
n_term.c_cc[VTIME]= 0;
}
if ((tcsetattr(fd, TCSAFLUSH, &n_term)) == -1)
return -1;
return 1;
}
#define UNDERLINE_START "\033[4m"
/* Bold, red. */
#define ALERT_START "\033[1;31m"
#define NORMAL_RESTORE "\033[0m"
static void
fputs_highlighted (char *text, char *highlight, FILE *ttyfo)
{
for (; *text; text ++)
{
/* Skip accelerator prefix. */
if (*text == '_')
{
text ++;
if (! *text)
break;
}
if (text == highlight)
fputs (UNDERLINE_START, ttyfo);
fputc (*text, ttyfo);
if (text == highlight)
fputs (NORMAL_RESTORE, ttyfo);
}
}
static char
button (char *text, char *default_text, FILE *ttyfo)
{
char *highlight;
int use_default = 0;
if (! text)
return 0;
/* Skip any leading white space. */
while (*text == ' ')
text ++;
highlight = text;
while ((highlight = strchr (highlight, '_')))
{
highlight = highlight + 1;
if (*highlight == '_')
{
/* Escaped underscore. Skip both characters. */
highlight++;
continue;
}
if (!isalnum (*highlight))
/* Unusable accelerator. */
continue;
break;
}
if (! highlight)
/* Not accelerator. Take the first alpha-numeric character. */
{
highlight = text;
while (*highlight && !isalnum (*highlight))
highlight ++;
}
if (! *highlight)
/* Hmm, no alpha-numeric characters. */
{
if (! default_text)
return 0;
highlight = default_text;
use_default = 1;
}
fputs (" ", ttyfo);
fputs_highlighted (text, highlight, ttyfo);
if (use_default)
{
fputs (" (", ttyfo);
fputs_highlighted (default_text, highlight, ttyfo);
fputc (')', ttyfo);
}
fputc ('\n', ttyfo);
return tolower (*highlight);
}
static void
dump_error_text (FILE *ttyfo, const char *text)
{
int lines = 0;
if (! text || ! *text)
return;
for (;;)
{
const char *eol = strchr (text, '\n');
if (! eol)
eol = text + strlen (text);
lines ++;
fwrite ("\n *** ", 6, 1, ttyfo);
fputs (ALERT_START, ttyfo);
fwrite (text, (size_t) (eol - text), 1, ttyfo);
fputs (NORMAL_RESTORE, ttyfo);
if (! *eol)
break;
text = eol + 1;
}
if (lines > 1)
fputc ('\n', ttyfo);
else
fwrite (" ***\n", 5, 1, ttyfo);
fputc ('\n', ttyfo);
}
static int
confirm (pinentry_t pinentry, FILE *ttyfi, FILE *ttyfo)
{
char *msg;
char *msgbuffer = NULL;
char ok = 0;
char notok = 0;
char cancel = 0;
int ret;
dump_error_text (ttyfo, pinentry->error);
msg = pinentry->description;
if (! msg)
{
/* If there is no description, fallback to the title. */
msg = msgbuffer = pinentry_get_title (pinentry);
}
if (! msg)
msg = "Confirm:";
if (msg)
{
fputs (msg, ttyfo);
fputc ('\n', ttyfo);
}
free (msgbuffer);
fflush (ttyfo);
if (pinentry->ok)
ok = button (pinentry->ok, "OK", ttyfo);
else if (pinentry->default_ok)
ok = button (pinentry->default_ok, "OK", ttyfo);
else
ok = button ("OK", NULL, ttyfo);
if (! pinentry->one_button)
{
if (pinentry->cancel)
cancel = button (pinentry->cancel, "Cancel", ttyfo);
else if (pinentry->default_cancel)
cancel = button (pinentry->default_cancel, "Cancel", ttyfo);
if (pinentry->notok)
notok = button (pinentry->notok, "No", ttyfo);
}
while (1)
{
int input;
if (pinentry->one_button)
fprintf (ttyfo, "Press any key to continue.");
else
{
fputc ('[', ttyfo);
if (ok)
fputc (ok, ttyfo);
if (cancel)
fputc (cancel, ttyfo);
if (notok)
fputc (notok, ttyfo);
fputs("]? ", ttyfo);
}
fflush (ttyfo);
input = fgetc (ttyfi);
if (input == EOF)
{
pinentry->close_button = 1;
pinentry->canceled = 1;
#ifndef HAVE_DOSISH_SYSTEM
if (!timed_out && errno == EINTR)
pinentry->specific_err = gpg_error (GPG_ERR_FULLY_CANCELED);
#endif
ret = 0;
break;
}
else
{
fprintf (ttyfo, "%c\n", input);
input = tolower (input);
}
if (pinentry->one_button)
{
ret = 1;
break;
}
if (cancel && input == cancel)
{
pinentry->canceled = 1;
ret = 0;
break;
}
else if (notok && input == notok)
{
ret = 0;
break;
}
else if (ok && input == ok)
{
ret = 1;
break;
}
else
{
fprintf (ttyfo, "Invalid selection.\n");
}
}
#ifndef HAVE_DOSISH_SYSTEM
if (timed_out)
pinentry->specific_err = gpg_error (GPG_ERR_TIMEOUT);
#endif
return ret;
}
static char *
read_password (pinentry_t pinentry, FILE *ttyfi, FILE *ttyfo)
{
int done = 0;
int len = 128;
int count = 0;
char *buffer;
(void) ttyfo;
buffer = secmem_malloc (len);
if (! buffer)
return NULL;
while (!done)
{
int c;
if (count == len - 1)
/* Double the buffer's size. Note: we check if count is len -
1 and not len so that we always have space for the NUL
character. */
{
int new_len = 2 * len;
char *tmp = secmem_realloc (buffer, new_len);
if (! tmp)
{
secmem_free (tmp);
return NULL;
}
buffer = tmp;
len = new_len;
}
c = fgetc (ttyfi);
switch (c)
{
case EOF:
done = -1;
#ifndef HAVE_DOSISH_SYSTEM
if (!timed_out && errno == EINTR)
pinentry->specific_err = gpg_error (GPG_ERR_FULLY_CANCELED);
#endif
break;
case '\n':
done = 1;
break;
default:
buffer[count ++] = c;
break;
}
}
buffer[count] = '\0';
if (done == -1)
{
secmem_free (buffer);
return NULL;
}
return buffer;
}
static int
password (pinentry_t pinentry, FILE *ttyfi, FILE *ttyfo)
{
char *msg;
char *msgbuffer = NULL;
int done = 0;
msg = pinentry->description;
if (! msg)
msg = msgbuffer = pinentry_get_title (pinentry);
if (! msg)
msg = "Enter your passphrase.";
dump_error_text (ttyfo, pinentry->error);
fprintf (ttyfo, "%s\n", msg);
free (msgbuffer);
while (! done)
{
char *passphrase;
char *prompt = pinentry->prompt;
if (! prompt || !*prompt)
prompt = "PIN";
fprintf (ttyfo, "%s%s ",
prompt,
/* Make sure the prompt ends in a : or a question mark. */
(prompt[strlen(prompt) - 1] == ':'
|| prompt[strlen(prompt) - 1] == '?') ? "" : ":");
fflush (ttyfo);
passphrase = read_password (pinentry, ttyfi, ttyfo);
fputc ('\n', ttyfo);
if (! passphrase)
{
done = -1;
break;
}
if (! pinentry->repeat_passphrase)
done = 1;
else
{
char *passphrase2;
prompt = pinentry->repeat_passphrase;
fprintf (ttyfo, "%s%s ",
prompt,
/* Make sure the prompt ends in a : or a question mark. */
(prompt[strlen(prompt) - 1] == ':'
|| prompt[strlen(prompt) - 1] == '?') ? "" : ":");
fflush (ttyfo);
passphrase2 = read_password (pinentry, ttyfi, ttyfo);
fputc ('\n', ttyfo);
if (! passphrase2)
{
done = -1;
break;
}
if (strcmp (passphrase, passphrase2) == 0)
{
pinentry->repeat_okay = 1;
done = 1;
}
else
dump_error_text (ttyfo,
pinentry->repeat_error_string
?: "Passphrases don't match.");
secmem_free (passphrase2);
}
if (done == 1)
pinentry_setbuffer_use (pinentry, passphrase, 0);
else
secmem_free (passphrase);
}
#ifndef HAVE_DOSISH_SYSTEM
if (timed_out)
pinentry->specific_err = gpg_error (GPG_ERR_TIMEOUT);
#endif
return done;
}
/* If a touch has been registered, touch that file. */
static void
do_touch_file(pinentry_t pinentry)
{
#ifdef HAVE_UTIME_H
struct stat st;
time_t tim;
if (!pinentry->touch_file || !*pinentry->touch_file)
return;
if (stat(pinentry->touch_file, &st))
return; /* Oops. */
/* Make sure that we actually update the mtime. */
while ((tim = time(NULL)) == st.st_mtime)
sleep(1);
/* Update but ignore errors as we can't do anything in that case.
Printing error messages may even clubber the display further. */
utime (pinentry->touch_file, NULL);
#endif /*HAVE_UTIME_H*/
}
#ifndef HAVE_DOSISH_SYSTEM
static void
catchsig (int sig)
{
if (sig == SIGALRM)
timed_out = 1;
}
#endif
int
tty_cmd_handler (pinentry_t pinentry)
{
int rc = 0;
FILE *ttyfi = stdin;
FILE *ttyfo = stdout;
int saved_errno = 0;
#ifndef HAVE_DOSISH_SYSTEM
timed_out = 0;
if (pinentry->timeout)
{
struct sigaction sa;
memset (&sa, 0, sizeof(sa));
sa.sa_handler = catchsig;
sigaction (SIGALRM, &sa, NULL);
sigaction (SIGINT, &sa, NULL);
alarm (pinentry->timeout);
}
#endif
if (pinentry->ttyname)
{
ttyfi = fopen (pinentry->ttyname, "r");
if (!ttyfi)
return -1;
ttyfo = fopen (pinentry->ttyname, "w");
if (!ttyfo)
{
saved_errno = errno;
fclose (ttyfi);
errno = saved_errno;
return -1;
}
}
if (terminal_save (fileno (ttyfi)) < 0)
rc = -1;
else
{
if (terminal_setup (fileno (ttyfi), !!pinentry->pin) == -1)
{
saved_errno = errno;
fprintf (stderr, "terminal_setup failure, exiting\n");
rc = -1;
}
else
{
if (pinentry->pin)
rc = password (pinentry, ttyfi, ttyfo);
else
rc = confirm (pinentry, ttyfi, ttyfo);
terminal_restore (fileno (ttyfi));
do_touch_file (pinentry);
}
}
if (pinentry->ttyname)
{
fclose (ttyfi);
fclose (ttyfo);
}
if (saved_errno)
errno = saved_errno;
return rc;
}
pinentry_cmd_handler_t pinentry_cmd_handler = tty_cmd_handler;
int
main (int argc, char *argv[])
{
pinentry_init ("pinentry-tty");
/* Consumes all arguments. */
pinentry_parse_opts(argc, argv);
if (pinentry_loop ())
return 1;
return 0;
}