1 /* 2 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 2001 Markus Friedl. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 RCSID("$OpenBSD: readpass.c,v 1.27 2002/03/26 15:58:46 markus Exp $"); 32 33 #include "xmalloc.h" 34 #include "readpass.h" 35 #include "pathnames.h" 36 #include "log.h" 37 #include "ssh.h" 38 #include <langinfo.h> 39 40 static char * 41 ssh_askpass(char *askpass, const char *msg) 42 { 43 pid_t pid; 44 size_t len; 45 char *pass; 46 int p[2], status, ret; 47 char buf[1024]; 48 49 if (fflush(stdout) != 0) 50 error("ssh_askpass: fflush: %s", strerror(errno)); 51 if (askpass == NULL) 52 fatal("internal error: askpass undefined"); 53 if (pipe(p) < 0) { 54 error("ssh_askpass: pipe: %s", strerror(errno)); 55 return xstrdup(""); 56 } 57 if ((pid = fork()) < 0) { 58 error("ssh_askpass: fork: %s", strerror(errno)); 59 return xstrdup(""); 60 } 61 if (pid == 0) { 62 seteuid(getuid()); 63 setuid(getuid()); 64 close(p[0]); 65 if (dup2(p[1], STDOUT_FILENO) < 0) 66 fatal("ssh_askpass: dup2: %s", strerror(errno)); 67 execlp(askpass, askpass, msg, (char *) 0); 68 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); 69 } 70 close(p[1]); 71 72 len = ret = 0; 73 do { 74 ret = read(p[0], buf + len, sizeof(buf) - 1 - len); 75 if (ret == -1 && errno == EINTR) 76 continue; 77 if (ret <= 0) 78 break; 79 len += ret; 80 } while (sizeof(buf) - 1 - len > 0); 81 buf[len] = '\0'; 82 83 close(p[0]); 84 while (waitpid(pid, &status, 0) < 0) 85 if (errno != EINTR) 86 break; 87 88 buf[strcspn(buf, "\r\n")] = '\0'; 89 pass = xstrdup(buf); 90 memset(buf, 0, sizeof(buf)); 91 return pass; 92 } 93 94 /* 95 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the 96 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If 97 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no 98 * tty is available 99 */ 100 char * 101 read_passphrase(const char *prompt, int flags) 102 { 103 char *askpass = NULL, *ret, buf[1024]; 104 int rppflags, use_askpass = 0, ttyfd; 105 106 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; 107 if (flags & RP_ALLOW_STDIN) { 108 if (!isatty(STDIN_FILENO)) 109 use_askpass = 1; 110 } else { 111 rppflags |= RPP_REQUIRE_TTY; 112 ttyfd = open(_PATH_TTY, O_RDWR); 113 if (ttyfd >= 0) 114 close(ttyfd); 115 else 116 use_askpass = 1; 117 } 118 119 if (use_askpass && getenv("DISPLAY")) { 120 if (getenv(SSH_ASKPASS_ENV)) 121 askpass = getenv(SSH_ASKPASS_ENV); 122 else 123 askpass = _PATH_SSH_ASKPASS_DEFAULT; 124 return ssh_askpass(askpass, prompt); 125 } 126 127 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { 128 if (flags & RP_ALLOW_EOF) 129 return NULL; 130 return xstrdup(""); 131 } 132 133 ret = xstrdup(buf); 134 memset(buf, 'x', sizeof buf); 135 return ret; 136 } 137 138 int 139 ask_permission(const char *fmt, ...) 140 { 141 va_list args; 142 char *p, prompt[1024]; 143 int allowed = 0; 144 char *yeschar = nl_langinfo(YESSTR); 145 146 va_start(args, fmt); 147 vsnprintf(prompt, sizeof(prompt), fmt, args); 148 va_end(args); 149 150 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); 151 if (p != NULL) { 152 /* 153 * Accept empty responses and responses consisting 154 * of the word "yes" as affirmative. 155 */ 156 if (*p == '\0' || *p == '\n' || 157 strncasecmp(p, yeschar, 1) == 0) 158 allowed = 1; 159 xfree(p); 160 } 161 162 return (allowed); 163 } 164