143 lines
4.5 KiB
C
143 lines
4.5 KiB
C
/*-
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* Copyright 2009 Colin Percival
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "scrypt_platform.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <termios.h>
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#include <unistd.h>
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#include "warn.h"
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#include "readpass.h"
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#define MAXPASSLEN 2048
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/**
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* tarsnap_getpass(passwd, prompt, confirmprompt, devtty)
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* If ${devtty} is non-zero, read a password from /dev/tty if possible; if
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* not, read from stdin. If reading from a tty (either /dev/tty or stdin),
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* disable echo and prompt the user by printing ${prompt} to stderr. If
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* ${confirmprompt} is non-NULL, read a second password (prompting if a
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* terminal is being used) and repeat until the user enters the same password
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* twice. Return the password as a malloced NUL-terminated string via
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* ${passwd}. The obscure name is to avoid namespace collisions due to the
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* getpass / readpass / readpassphrase / etc. functions in various libraries.
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*/
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int
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tarsnap_readpass(char ** passwd, const char * prompt,
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const char * confirmprompt, int devtty)
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{
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FILE * readfrom;
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char passbuf[MAXPASSLEN];
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char confpassbuf[MAXPASSLEN];
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struct termios term, term_old;
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int usingtty;
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/*
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* If devtty != 0, try to open /dev/tty; if that fails, or if devtty
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* is zero, we'll read the password from stdin instead.
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*/
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if ((devtty == 0) || ((readfrom = fopen("/dev/tty", "r")) == NULL))
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readfrom = stdin;
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/* If we're reading from a terminal, try to disable echo. */
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if ((usingtty = isatty(fileno(readfrom))) != 0) {
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if (tcgetattr(fileno(readfrom), &term_old)) {
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warn("Cannot read terminal settings");
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goto err1;
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}
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memcpy(&term, &term_old, sizeof(struct termios));
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term.c_lflag = (term.c_lflag & ~ECHO) | ECHONL;
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if (tcsetattr(fileno(readfrom), TCSANOW, &term)) {
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warn("Cannot set terminal settings");
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goto err1;
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}
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}
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retry:
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/* If we have a terminal, prompt the user to enter the password. */
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if (usingtty)
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fprintf(stderr, "%s: ", prompt);
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/* Read the password. */
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if (fgets(passbuf, MAXPASSLEN, readfrom) == NULL) {
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warn("Cannot read password");
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goto err2;
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}
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/* Confirm the password if necessary. */
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if (confirmprompt != NULL) {
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if (usingtty)
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fprintf(stderr, "%s: ", confirmprompt);
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if (fgets(confpassbuf, MAXPASSLEN, readfrom) == NULL) {
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warn("Cannot read password");
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goto err2;
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}
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if (strcmp(passbuf, confpassbuf)) {
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fprintf(stderr,
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"Passwords mismatch, please try again\n");
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goto retry;
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}
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}
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/* Terminate the string at the first "\r" or "\n" (if any). */
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passbuf[strcspn(passbuf, "\r\n")] = '\0';
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/* If we changed terminal settings, reset them. */
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if (usingtty)
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tcsetattr(fileno(readfrom), TCSANOW, &term_old);
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/* Close /dev/tty if we opened it. */
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if (readfrom != stdin)
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fclose(readfrom);
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/* Copy the password out. */
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if ((*passwd = strdup(passbuf)) == NULL) {
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warn("Cannot allocate memory");
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goto err1;
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}
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/* Zero any stored passwords. */
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memset(passbuf, 0, MAXPASSLEN);
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memset(confpassbuf, 0, MAXPASSLEN);
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/* Success! */
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return (0);
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err2:
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/* Reset terminal settings if necessary. */
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if (usingtty)
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tcsetattr(fileno(readfrom), TCSAFLUSH, &term_old);
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err1:
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/* Close /dev/tty if we opened it. */
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if (readfrom != stdin)
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fclose(readfrom);
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/* Failure! */
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return (-1);
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}
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