/*      $OpenBSD: readpassphrase.c,v 1.29 2026/03/10 16:27:33 deraadt Exp $     */

/*
 * Copyright (c) 2000-2002, 2007, 2010
 *      Todd C. Miller <millert@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <readpassphrase.h>

static volatile sig_atomic_t signo[_NSIG];

static void handler(int);

char *
readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
{
        ssize_t nr;
        int input, output, save_errno, i, need_restart;
        char ch, *p, *end;
        struct termios term, oterm;
        struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
        struct sigaction savetstp, savettin, savettou, savepipe;

        /* I suppose we could alloc on demand in this case (XXX). */
        if (bufsiz == 0) {
                errno = EINVAL;
                return(NULL);
        }

restart:
        for (i = 0; i < _NSIG; i++)
                signo[i] = 0;
        nr = -1;
        save_errno = 0;
        need_restart = 0;
        /*
         * Read and write to /dev/tty if available.  If not, read from
         * stdin and write to stderr unless a tty is required.
         */
        if ((flags & RPP_STDIN) ||
            (input = output = __pledge_open(_PATH_TTY, O_RDWR | O_CLOEXEC)) == -1) {
                if (flags & RPP_REQUIRE_TTY) {
                        errno = ENOTTY;
                        return(NULL);
                }
                input = STDIN_FILENO;
                output = STDERR_FILENO;
        }

        /*
         * Turn off echo if possible.
         * If we are using a tty but are not the foreground pgrp this will
         * generate SIGTTOU, so do it *before* installing the signal handlers.
         */
        if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
                memcpy(&term, &oterm, sizeof(term));
                if (!(flags & RPP_ECHO_ON))
                        term.c_lflag &= ~(ECHO | ECHONL);
                if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
                        term.c_cc[VSTATUS] = _POSIX_VDISABLE;
                (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
        } else {
                memset(&term, 0, sizeof(term));
                term.c_lflag |= ECHO;
                memset(&oterm, 0, sizeof(oterm));
                oterm.c_lflag |= ECHO;
        }

        /*
         * Catch signals that would otherwise cause the user to end
         * up with echo turned off in the shell.  Don't worry about
         * things like SIGXCPU and SIGVTALRM for now.
         */
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;                /* don't restart system calls */
        sa.sa_handler = handler;
        (void)sigaction(SIGALRM, &sa, &savealrm);
        (void)sigaction(SIGHUP, &sa, &savehup);
        (void)sigaction(SIGINT, &sa, &saveint);
        (void)sigaction(SIGPIPE, &sa, &savepipe);
        (void)sigaction(SIGQUIT, &sa, &savequit);
        (void)sigaction(SIGTERM, &sa, &saveterm);
        (void)sigaction(SIGTSTP, &sa, &savetstp);
        (void)sigaction(SIGTTIN, &sa, &savettin);
        (void)sigaction(SIGTTOU, &sa, &savettou);

        if (!(flags & RPP_STDIN))
                (void)write(output, prompt, strlen(prompt));
        end = buf + bufsiz - 1;
        p = buf;
        while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
                if (p < end) {
                        if ((flags & RPP_SEVENBIT))
                                ch &= 0x7f;
                        if (isalpha((unsigned char)ch)) {
                                if ((flags & RPP_FORCELOWER))
                                        ch = (char)tolower((unsigned char)ch);
                                if ((flags & RPP_FORCEUPPER))
                                        ch = (char)toupper((unsigned char)ch);
                        }
                        *p++ = ch;
                }
        }
        *p = '\0';
        save_errno = errno;
        if (!(term.c_lflag & ECHO))
                (void)write(output, "\n", 1);

        /* Restore old terminal settings and signals. */
        if (memcmp(&term, &oterm, sizeof(term)) != 0) {
                const int sigttou = signo[SIGTTOU];

                /* Ignore SIGTTOU generated when we are not the fg pgrp. */
                while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
                    errno == EINTR && !signo[SIGTTOU])
                        continue;
                signo[SIGTTOU] = sigttou;
        }
        (void)sigaction(SIGALRM, &savealrm, NULL);
        (void)sigaction(SIGHUP, &savehup, NULL);
        (void)sigaction(SIGINT, &saveint, NULL);
        (void)sigaction(SIGQUIT, &savequit, NULL);
        (void)sigaction(SIGPIPE, &savepipe, NULL);
        (void)sigaction(SIGTERM, &saveterm, NULL);
        (void)sigaction(SIGTSTP, &savetstp, NULL);
        (void)sigaction(SIGTTIN, &savettin, NULL);
        (void)sigaction(SIGTTOU, &savettou, NULL);
        if (input != STDIN_FILENO)
                (void)close(input);

        /*
         * If we were interrupted by a signal, resend it to ourselves
         * now that we have restored the signal handlers.
         */
        for (i = 0; i < _NSIG; i++) {
                if (signo[i]) {
                        kill(getpid(), i);
                        switch (i) {
                        case SIGTSTP:
                        case SIGTTIN:
                        case SIGTTOU:
                                need_restart = 1;
                        }
                }
        }
        if (need_restart)
                goto restart;

        if (save_errno)
                errno = save_errno;
        return(nr == -1 ? NULL : buf);
}
DEF_WEAK(readpassphrase);

char *
getpass(const char *prompt)
{
        static char buf[_PASSWORD_LEN + 1];

        return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
}

static void handler(int s)
{

        signo[s] = 1;
}