usr/src/cmd/ssh/libopenbsd-compat/common/readpassphrase.c

   1 /*      $OpenBSD: readpassphrase.c,v 1.14 2002/06/28 01:43:58 millert Exp $     */
   2
   3 /*
   4  * Copyright (c) 2000-2002 Todd C. Miller <Todd.Miller@courtesan.com>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
  21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static const char rcsid[] = "$OpenBSD: readpassphrase.c,v 1.14 2002/06/28 01:43:58 millert Exp $";
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include "includes.h"
  35
  36 #ifndef HAVE_READPASSPHRASE
  37
  38 #include <termios.h>
  39 #include <readpassphrase.h>
  40
  41 #ifdef TCSASOFT
  42 # define _T_FLUSH       (TCSAFLUSH|TCSASOFT)
  43 #else
  44 # define _T_FLUSH       (TCSAFLUSH)
  45 #endif
  46
  47 /* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
  48 #if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
  49 #  define _POSIX_VDISABLE       VDISABLE
  50 #endif
  51
  52 static volatile sig_atomic_t signo;
  53
  54 static void handler(int);
  55
  56 char *
  57 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
  58 {
  59         ssize_t nr;
  60         int input, output, save_errno;
  61         char ch, *p, *end;
  62         struct termios term, oterm;
  63         struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
  64         struct sigaction savetstp, savettin, savettou, savepipe;
  65
  66         /* I suppose we could alloc on demand in this case (XXX). */
  67         if (bufsiz == 0) {
  68                 errno = EINVAL;
  69                 return(NULL);
  70         }
  71
  72 restart:
  73         signo = 0;
  74         /*
  75          * Read and write to /dev/tty if available.  If not, read from
  76          * stdin and write to stderr unless a tty is required.
  77          */
  78         if ((flags & RPP_STDIN) ||
  79             (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
  80                 if (flags & RPP_REQUIRE_TTY) {
  81                         errno = ENOTTY;
  82                         return(NULL);
  83                 }
  84                 input = STDIN_FILENO;
  85                 output = STDERR_FILENO;
  86         }
  87
  88         /*
  89          * Catch signals that would otherwise cause the user to end
  90          * up with echo turned off in the shell.  Don't worry about
  91          * things like SIGXCPU and SIGVTALRM for now.
  92          */
  93         sigemptyset(&sa.sa_mask);
  94         sa.sa_flags = 0;                /* don't restart system calls */
  95         sa.sa_handler = handler;
  96         (void)sigaction(SIGALRM, &sa, &savealrm);
  97         (void)sigaction(SIGHUP, &sa, &savehup);
  98         (void)sigaction(SIGINT, &sa, &saveint);
  99         (void)sigaction(SIGPIPE, &sa, &savepipe);
 100         (void)sigaction(SIGQUIT, &sa, &savequit);
 101         (void)sigaction(SIGTERM, &sa, &saveterm);
 102         (void)sigaction(SIGTSTP, &sa, &savetstp);
 103         (void)sigaction(SIGTTIN, &sa, &savettin);
 104         (void)sigaction(SIGTTOU, &sa, &savettou);
 105
 106         /* Turn off echo if possible. */
 107         if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
 108                 memcpy(&term, &oterm, sizeof(term));
 109                 if (!(flags & RPP_ECHO_ON))
 110                         term.c_lflag &= ~(ECHO | ECHONL);
 111 #ifdef VSTATUS
 112                 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
 113                         term.c_cc[VSTATUS] = _POSIX_VDISABLE;
 114 #endif
 115                 (void)tcsetattr(input, _T_FLUSH, &term);
 116         } else {
 117                 memset(&term, 0, sizeof(term));
 118                 term.c_lflag |= ECHO;
 119                 memset(&oterm, 0, sizeof(oterm));
 120                 oterm.c_lflag |= ECHO;
 121         }
 122
 123         if (!(flags & RPP_STDIN))
 124                 (void)write(output, prompt, strlen(prompt));
 125         end = buf + bufsiz - 1;
 126         for (p = buf; (nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r';) {
 127                 if (p < end) {
 128                         if ((flags & RPP_SEVENBIT))
 129                                 ch &= 0x7f;
 130                         if (isalpha(ch)) {
 131                                 if ((flags & RPP_FORCELOWER))
 132                                         ch = tolower(ch);
 133                                 if ((flags & RPP_FORCEUPPER))
 134                                         ch = toupper(ch);
 135                         }
 136                         *p++ = ch;
 137                 }
 138         }
 139         *p = '\0';
 140         save_errno = errno;
 141         if (!(term.c_lflag & ECHO))
 142                 (void)write(output, "\n", 1);
 143
 144         /* Restore old terminal settings and signals. */
 145         if (memcmp(&term, &oterm, sizeof(term)) != 0)
 146                 (void)tcsetattr(input, _T_FLUSH, &oterm);
 147         (void)sigaction(SIGALRM, &savealrm, NULL);
 148         (void)sigaction(SIGHUP, &savehup, NULL);
 149         (void)sigaction(SIGINT, &saveint, NULL);
 150         (void)sigaction(SIGQUIT, &savequit, NULL);
 151         (void)sigaction(SIGPIPE, &savepipe, NULL);
 152         (void)sigaction(SIGTERM, &saveterm, NULL);
 153         (void)sigaction(SIGTSTP, &savetstp, NULL);
 154         (void)sigaction(SIGTTIN, &savettin, NULL);
 155         if (input != STDIN_FILENO)
 156                 (void)close(input);
 157
 158         /*
 159          * If we were interrupted by a signal, resend it to ourselves
 160          * now that we have restored the signal handlers.
 161          */
 162         if (signo) {
 163                 kill(getpid(), signo);
 164                 switch (signo) {
 165                 case SIGTSTP:
 166                 case SIGTTIN:
 167                 case SIGTTOU:
 168                         goto restart;
 169                 }
 170         }
 171
 172         errno = save_errno;
 173         return(nr == -1 ? NULL : buf);
 174 }
 175
 176 #if 0
 177 char *
 178 getpass(const char *prompt)
 179 {
 180         static char buf[_PASSWORD_LEN + 1];
 181
 182         return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
 183 }
 184 #endif
 185
 186 static void handler(int s)
 187 {
 188         signo = s;
 189 }
 190 #endif /* HAVE_READPASSPHRASE */
 191
 192 #pragma ident   "%Z%%M% %I%     %E% SMI"