115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
/*
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readpass.c
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Author: Tatu Ylonen <ylo@cs.hut.fi>
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Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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All rights reserved
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Created: Mon Jul 10 22:08:59 1995 ylo
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Functions for reading passphrases and passwords.
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*/
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#include "includes.h"
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RCSID("$Id: readpass.c,v 1.1 1999/10/27 03:42:44 damien Exp $");
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#include "xmalloc.h"
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#include "ssh.h"
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/* Saved old terminal mode for read_passphrase. */
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static struct termios saved_tio;
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/* Old interrupt signal handler for read_passphrase. */
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static void (*old_handler)(int sig) = NULL;
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/* Interrupt signal handler for read_passphrase. */
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void intr_handler(int sig)
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{
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/* Restore terminal modes. */
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tcsetattr(fileno(stdin), TCSANOW, &saved_tio);
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/* Restore the old signal handler. */
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signal(sig, old_handler);
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/* Resend the signal, with the old handler. */
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kill(getpid(), sig);
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}
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/* Reads a passphrase from /dev/tty with echo turned off. Returns the
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passphrase (allocated with xmalloc). Exits if EOF is encountered.
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The passphrase if read from stdin if from_stdin is true (as is the
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case with ssh-keygen). */
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char *read_passphrase(const char *prompt, int from_stdin)
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{
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char buf[1024], *cp;
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struct termios tio;
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FILE *f;
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if (from_stdin)
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f = stdin;
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else
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{
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/* Read the passphrase from /dev/tty to make it possible to ask it even
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when stdin has been redirected. */
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f = fopen("/dev/tty", "r");
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if (!f)
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{
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/* No controlling terminal and no DISPLAY. Nowhere to read. */
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fprintf(stderr, "You have no controlling tty and no DISPLAY. Cannot read passphrase.\n");
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exit(1);
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}
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}
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/* Display the prompt (on stderr because stdout might be redirected). */
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fflush(stdout);
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fprintf(stderr, "%s", prompt);
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fflush(stderr);
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/* Get terminal modes. */
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tcgetattr(fileno(f), &tio);
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saved_tio = tio;
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/* Save signal handler and set the new handler. */
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old_handler = signal(SIGINT, intr_handler);
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/* Set new terminal modes disabling all echo. */
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tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
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tcsetattr(fileno(f), TCSANOW, &tio);
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/* Read the passphrase from the terminal. */
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if (fgets(buf, sizeof(buf), f) == NULL)
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{
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/* Got EOF. Just exit. */
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/* Restore terminal modes. */
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tcsetattr(fileno(f), TCSANOW, &saved_tio);
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/* Restore the signal handler. */
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signal(SIGINT, old_handler);
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/* Print a newline (the prompt probably didn\'t have one). */
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fprintf(stderr, "\n");
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/* Close the file. */
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if (f != stdin)
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fclose(f);
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exit(1);
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}
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/* Restore terminal modes. */
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tcsetattr(fileno(f), TCSANOW, &saved_tio);
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/* Restore the signal handler. */
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(void)signal(SIGINT, old_handler);
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/* Remove newline from the passphrase. */
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if (strchr(buf, '\n'))
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*strchr(buf, '\n') = 0;
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/* Allocate a copy of the passphrase. */
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cp = xstrdup(buf);
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/* Clear the buffer so we don\'t leave copies of the passphrase laying
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around. */
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memset(buf, 0, sizeof(buf));
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/* Print a newline since the prompt probably didn\'t have one. */
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fprintf(stderr, "\n");
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/* Close the file. */
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if (f != stdin)
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fclose(f);
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return cp;
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}
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