readpass.c revision 137015
1203287Srnoland/* 2203287Srnoland * Copyright (c) 2001 Markus Friedl. All rights reserved. 3203287Srnoland * 4203287Srnoland * Redistribution and use in source and binary forms, with or without 5203287Srnoland * modification, are permitted provided that the following conditions 6203287Srnoland * are met: 7203287Srnoland * 1. Redistributions of source code must retain the above copyright 8203287Srnoland * notice, this list of conditions and the following disclaimer. 9203287Srnoland * 2. Redistributions in binary form must reproduce the above copyright 10203287Srnoland * notice, this list of conditions and the following disclaimer in the 11203287Srnoland * documentation and/or other materials provided with the distribution. 12203287Srnoland * 13203287Srnoland * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14203287Srnoland * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 15203287Srnoland * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16203287Srnoland * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 17203287Srnoland * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18203287Srnoland * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 19203287Srnoland * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 20203287Srnoland * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21203287Srnoland * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 22203287Srnoland * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23203287Srnoland */ 24203287Srnoland 25203287Srnoland#include "includes.h" 26203287SrnolandRCSID("$OpenBSD: readpass.c,v 1.30 2004/06/17 15:10:14 djm Exp $"); 27203287Srnoland 28203287Srnoland#include "xmalloc.h" 29203287Srnoland#include "misc.h" 30203287Srnoland#include "pathnames.h" 31203287Srnoland#include "log.h" 32203287Srnoland#include "ssh.h" 33203287Srnoland 34203287Srnolandstatic char * 35203287Srnolandssh_askpass(char *askpass, const char *msg) 36203287Srnoland{ 37203287Srnoland pid_t pid; 38203287Srnoland size_t len; 39203287Srnoland char *pass; 40203287Srnoland int p[2], status, ret; 41203287Srnoland char buf[1024]; 42203287Srnoland 43203287Srnoland if (fflush(stdout) != 0) 44203287Srnoland error("ssh_askpass: fflush: %s", strerror(errno)); 45203287Srnoland if (askpass == NULL) 46203287Srnoland fatal("internal error: askpass undefined"); 47203287Srnoland if (pipe(p) < 0) { 48203287Srnoland error("ssh_askpass: pipe: %s", strerror(errno)); 49203287Srnoland return NULL; 50203287Srnoland } 51203287Srnoland if ((pid = fork()) < 0) { 52203287Srnoland error("ssh_askpass: fork: %s", strerror(errno)); 53203287Srnoland return NULL; 54203287Srnoland } 55203287Srnoland if (pid == 0) { 56203287Srnoland seteuid(getuid()); 57203287Srnoland setuid(getuid()); 58203287Srnoland close(p[0]); 59203287Srnoland if (dup2(p[1], STDOUT_FILENO) < 0) 60203287Srnoland fatal("ssh_askpass: dup2: %s", strerror(errno)); 61203287Srnoland execlp(askpass, askpass, msg, (char *) 0); 62203287Srnoland fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); 63203287Srnoland } 64203287Srnoland close(p[1]); 65203287Srnoland 66203287Srnoland len = ret = 0; 67203287Srnoland do { 68203287Srnoland ret = read(p[0], buf + len, sizeof(buf) - 1 - len); 69 if (ret == -1 && errno == EINTR) 70 continue; 71 if (ret <= 0) 72 break; 73 len += ret; 74 } while (sizeof(buf) - 1 - len > 0); 75 buf[len] = '\0'; 76 77 close(p[0]); 78 while (waitpid(pid, &status, 0) < 0) 79 if (errno != EINTR) 80 break; 81 82 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { 83 memset(buf, 0, sizeof(buf)); 84 return NULL; 85 } 86 87 buf[strcspn(buf, "\r\n")] = '\0'; 88 pass = xstrdup(buf); 89 memset(buf, 0, sizeof(buf)); 90 return pass; 91} 92 93/* 94 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the 95 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If 96 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no 97 * tty is available 98 */ 99char * 100read_passphrase(const char *prompt, int flags) 101{ 102 char *askpass = NULL, *ret, buf[1024]; 103 int rppflags, use_askpass = 0, ttyfd; 104 105 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; 106 if (flags & RP_USE_ASKPASS) 107 use_askpass = 1; 108 else if (flags & RP_ALLOW_STDIN) { 109 if (!isatty(STDIN_FILENO)) 110 use_askpass = 1; 111 } else { 112 rppflags |= RPP_REQUIRE_TTY; 113 ttyfd = open(_PATH_TTY, O_RDWR); 114 if (ttyfd >= 0) 115 close(ttyfd); 116 else 117 use_askpass = 1; 118 } 119 120 if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL) 121 return (flags & RP_ALLOW_EOF) ? NULL : xstrdup(""); 122 123 if (use_askpass && getenv("DISPLAY")) { 124 if (getenv(SSH_ASKPASS_ENV)) 125 askpass = getenv(SSH_ASKPASS_ENV); 126 else 127 askpass = _PATH_SSH_ASKPASS_DEFAULT; 128 if ((ret = ssh_askpass(askpass, prompt)) == NULL) 129 if (!(flags & RP_ALLOW_EOF)) 130 return xstrdup(""); 131 return ret; 132 } 133 134 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { 135 if (flags & RP_ALLOW_EOF) 136 return NULL; 137 return xstrdup(""); 138 } 139 140 ret = xstrdup(buf); 141 memset(buf, 'x', sizeof buf); 142 return ret; 143} 144