1 /* 2 * Copyright (c) 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include "includes.h" 35 RCSID("$OpenBSD: readpass.c,v 1.22 2001/07/14 15:10:16 stevesk Exp $"); 36 37 #include <readpassphrase.h> 38 39 #include "xmalloc.h" 40 #include "readpass.h" 41 #include "pathnames.h" 42 #include "log.h" 43 #include "ssh.h" 44 45 static char * 46 ssh_askpass(char *askpass, const char *msg) 47 { 48 pid_t pid; 49 size_t len; 50 char *nl, *pass; 51 int p[2], status; 52 char buf[1024]; 53 54 if (fflush(stdout) != 0) 55 error("ssh_askpass: fflush: %s", strerror(errno)); 56 if (askpass == NULL) 57 fatal("internal error: askpass undefined"); 58 if (pipe(p) < 0) { 59 error("ssh_askpass: pipe: %s", strerror(errno)); 60 return xstrdup(""); 61 } 62 if ((pid = fork()) < 0) { 63 error("ssh_askpass: fork: %s", strerror(errno)); 64 return xstrdup(""); 65 } 66 if (pid == 0) { 67 seteuid(getuid()); 68 setuid(getuid()); 69 close(p[0]); 70 if (dup2(p[1], STDOUT_FILENO) < 0) 71 fatal("ssh_askpass: dup2: %s", strerror(errno)); 72 execlp(askpass, askpass, msg, (char *) 0); 73 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); 74 } 75 close(p[1]); 76 len = read(p[0], buf, sizeof buf); 77 close(p[0]); 78 while (waitpid(pid, &status, 0) < 0) 79 if (errno != EINTR) 80 break; 81 if (len <= 1) 82 return xstrdup(""); 83 nl = strchr(buf, '\n'); 84 if (nl) 85 *nl = '\0'; 86 pass = xstrdup(buf); 87 memset(buf, 0, sizeof(buf)); 88 return pass; 89 } 90 91 /* 92 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the 93 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If 94 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no 95 * tty is available 96 */ 97 char * 98 read_passphrase(const char *prompt, int flags) 99 { 100 char *askpass = NULL, *ret, buf[1024]; 101 int rppflags, use_askpass = 0, ttyfd; 102 103 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; 104 if (flags & RP_ALLOW_STDIN) { 105 if (!isatty(STDIN_FILENO)) 106 use_askpass = 1; 107 } else { 108 rppflags |= RPP_REQUIRE_TTY; 109 ttyfd = open("/dev/tty", O_RDWR); 110 if (ttyfd >= 0) 111 close(ttyfd); 112 else 113 use_askpass = 1; 114 } 115 116 if (use_askpass && getenv("DISPLAY")) { 117 if (getenv(SSH_ASKPASS_ENV)) 118 askpass = getenv(SSH_ASKPASS_ENV); 119 else 120 askpass = _PATH_SSH_ASKPASS_DEFAULT; 121 return ssh_askpass(askpass, prompt); 122 } 123 124 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) 125 return xstrdup(""); 126 127 ret = xstrdup(buf); 128 memset(buf, 'x', sizeof buf); 129 return ret; 130 } 131