Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 1 | /* $OpenBSD: readpass.c,v 1.44 2006/07/22 20:48:23 stevesk Exp $ */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 2 | /* |
Damien Miller | 3606ee2 | 2002-02-13 14:05:23 +1100 | [diff] [blame] | 3 | * Copyright (c) 2001 Markus Friedl. All rights reserved. |
Damien Miller | 50945fa | 1999-12-09 10:31:37 +1100 | [diff] [blame] | 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. |
Damien Miller | 50945fa | 1999-12-09 10:31:37 +1100 | [diff] [blame] | 13 | * |
Damien Miller | 3606ee2 | 2002-02-13 14:05:23 +1100 | [diff] [blame] | 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 24 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 25 | |
| 26 | #include "includes.h" |
Damien Miller | 9cf6d07 | 2006-03-15 11:29:24 +1100 | [diff] [blame] | 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/wait.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 30 | |
Darren Tucker | 3997249 | 2006-07-12 22:22:46 +1000 | [diff] [blame] | 31 | #include <errno.h> |
Damien Miller | 57cf638 | 2006-07-10 21:13:46 +1000 | [diff] [blame] | 32 | #include <fcntl.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 33 | #ifdef HAVE_PATHS_H |
Damien Miller | a9263d0 | 2006-03-15 11:18:26 +1100 | [diff] [blame] | 34 | # include <paths.h> |
Damien Miller | 03e2003 | 2006-03-15 11:16:59 +1100 | [diff] [blame] | 35 | #endif |
Darren Tucker | 5d19626 | 2006-07-12 22:15:16 +1000 | [diff] [blame] | 36 | #include <stdarg.h> |
Damien Miller | e3476ed | 2006-07-24 14:13:33 +1000 | [diff] [blame] | 37 | #include <string.h> |
Damien Miller | e6b3b61 | 2006-07-24 14:01:23 +1000 | [diff] [blame] | 38 | #include <unistd.h> |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 39 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 40 | #include "xmalloc.h" |
Darren Tucker | e608ca2 | 2004-05-13 16:15:47 +1000 | [diff] [blame] | 41 | #include "misc.h" |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 42 | #include "pathnames.h" |
| 43 | #include "log.h" |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 44 | #include "ssh.h" |
Damien Miller | 6b4069a | 2006-06-13 13:05:15 +1000 | [diff] [blame] | 45 | #include "uidswap.h" |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 46 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 47 | static char * |
Ben Lindstrom | 6d84931 | 2001-05-02 01:30:32 +0000 | [diff] [blame] | 48 | ssh_askpass(char *askpass, const char *msg) |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 49 | { |
| 50 | pid_t pid; |
| 51 | size_t len; |
Damien Miller | 637b8ae | 2001-11-12 11:05:20 +1100 | [diff] [blame] | 52 | char *pass; |
Damien Miller | f451e22 | 2002-01-22 23:05:31 +1100 | [diff] [blame] | 53 | int p[2], status, ret; |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 54 | char buf[1024]; |
| 55 | |
| 56 | if (fflush(stdout) != 0) |
| 57 | error("ssh_askpass: fflush: %s", strerror(errno)); |
| 58 | if (askpass == NULL) |
| 59 | fatal("internal error: askpass undefined"); |
Damien Miller | 07ab49e | 2001-07-14 12:19:56 +1000 | [diff] [blame] | 60 | if (pipe(p) < 0) { |
| 61 | error("ssh_askpass: pipe: %s", strerror(errno)); |
Damien Miller | 6c71179 | 2003-01-24 11:36:23 +1100 | [diff] [blame] | 62 | return NULL; |
Damien Miller | 07ab49e | 2001-07-14 12:19:56 +1000 | [diff] [blame] | 63 | } |
| 64 | if ((pid = fork()) < 0) { |
| 65 | error("ssh_askpass: fork: %s", strerror(errno)); |
Damien Miller | 6c71179 | 2003-01-24 11:36:23 +1100 | [diff] [blame] | 66 | return NULL; |
Damien Miller | 07ab49e | 2001-07-14 12:19:56 +1000 | [diff] [blame] | 67 | } |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 68 | if (pid == 0) { |
Damien Miller | 2e5fe88 | 2006-06-13 13:10:00 +1000 | [diff] [blame] | 69 | permanently_drop_suid(getuid()); |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 70 | close(p[0]); |
| 71 | if (dup2(p[1], STDOUT_FILENO) < 0) |
| 72 | fatal("ssh_askpass: dup2: %s", strerror(errno)); |
| 73 | execlp(askpass, askpass, msg, (char *) 0); |
| 74 | fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); |
| 75 | } |
| 76 | close(p[1]); |
Damien Miller | f451e22 | 2002-01-22 23:05:31 +1100 | [diff] [blame] | 77 | |
| 78 | len = ret = 0; |
| 79 | do { |
| 80 | ret = read(p[0], buf + len, sizeof(buf) - 1 - len); |
| 81 | if (ret == -1 && errno == EINTR) |
| 82 | continue; |
| 83 | if (ret <= 0) |
| 84 | break; |
| 85 | len += ret; |
| 86 | } while (sizeof(buf) - 1 - len > 0); |
| 87 | buf[len] = '\0'; |
| 88 | |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 89 | close(p[0]); |
| 90 | while (waitpid(pid, &status, 0) < 0) |
| 91 | if (errno != EINTR) |
| 92 | break; |
Damien Miller | f451e22 | 2002-01-22 23:05:31 +1100 | [diff] [blame] | 93 | |
Damien Miller | 6c71179 | 2003-01-24 11:36:23 +1100 | [diff] [blame] | 94 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
| 95 | memset(buf, 0, sizeof(buf)); |
| 96 | return NULL; |
| 97 | } |
| 98 | |
Damien Miller | 637b8ae | 2001-11-12 11:05:20 +1100 | [diff] [blame] | 99 | buf[strcspn(buf, "\r\n")] = '\0'; |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 100 | pass = xstrdup(buf); |
| 101 | memset(buf, 0, sizeof(buf)); |
| 102 | return pass; |
| 103 | } |
| 104 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 105 | /* |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 106 | * Reads a passphrase from /dev/tty with echo turned off/on. Returns the |
| 107 | * passphrase (allocated with xmalloc). Exits if EOF is encountered. If |
| 108 | * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no |
| 109 | * tty is available |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 110 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 111 | char * |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 112 | read_passphrase(const char *prompt, int flags) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 113 | { |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 114 | char *askpass = NULL, *ret, buf[1024]; |
| 115 | int rppflags, use_askpass = 0, ttyfd; |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 116 | |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 117 | rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; |
Damien Miller | 23f0770 | 2004-06-18 01:19:03 +1000 | [diff] [blame] | 118 | if (flags & RP_USE_ASKPASS) |
| 119 | use_askpass = 1; |
| 120 | else if (flags & RP_ALLOW_STDIN) { |
Damien Miller | d2ebd45 | 2005-05-26 12:07:47 +1000 | [diff] [blame] | 121 | if (!isatty(STDIN_FILENO)) { |
Damien Miller | ddeb752 | 2005-05-26 12:05:28 +1000 | [diff] [blame] | 122 | debug("read_passphrase: stdin is not a tty"); |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 123 | use_askpass = 1; |
Damien Miller | d2ebd45 | 2005-05-26 12:07:47 +1000 | [diff] [blame] | 124 | } |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 125 | } else { |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 126 | rppflags |= RPP_REQUIRE_TTY; |
Damien Miller | 85830d1 | 2002-01-22 23:24:51 +1100 | [diff] [blame] | 127 | ttyfd = open(_PATH_TTY, O_RDWR); |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 128 | if (ttyfd >= 0) |
| 129 | close(ttyfd); |
Damien Miller | ddeb752 | 2005-05-26 12:05:28 +1000 | [diff] [blame] | 130 | else { |
| 131 | debug("read_passphrase: can't open %s: %s", _PATH_TTY, |
| 132 | strerror(errno)); |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 133 | use_askpass = 1; |
Damien Miller | ddeb752 | 2005-05-26 12:05:28 +1000 | [diff] [blame] | 134 | } |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 135 | } |
| 136 | |
Damien Miller | 23f0770 | 2004-06-18 01:19:03 +1000 | [diff] [blame] | 137 | if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL) |
| 138 | return (flags & RP_ALLOW_EOF) ? NULL : xstrdup(""); |
| 139 | |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 140 | if (use_askpass && getenv("DISPLAY")) { |
| 141 | if (getenv(SSH_ASKPASS_ENV)) |
| 142 | askpass = getenv(SSH_ASKPASS_ENV); |
| 143 | else |
| 144 | askpass = _PATH_SSH_ASKPASS_DEFAULT; |
Damien Miller | 6c71179 | 2003-01-24 11:36:23 +1100 | [diff] [blame] | 145 | if ((ret = ssh_askpass(askpass, prompt)) == NULL) |
| 146 | if (!(flags & RP_ALLOW_EOF)) |
| 147 | return xstrdup(""); |
| 148 | return ret; |
Ben Lindstrom | 5eb97b6 | 2001-04-19 20:33:07 +0000 | [diff] [blame] | 149 | } |
| 150 | |
Ben Lindstrom | 38a69e6 | 2002-03-27 17:28:46 +0000 | [diff] [blame] | 151 | if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { |
| 152 | if (flags & RP_ALLOW_EOF) |
| 153 | return NULL; |
Ben Lindstrom | 4f42d8c | 2001-07-04 05:19:27 +0000 | [diff] [blame] | 154 | return xstrdup(""); |
Ben Lindstrom | 38a69e6 | 2002-03-27 17:28:46 +0000 | [diff] [blame] | 155 | } |
Ben Lindstrom | 949974b | 2001-06-25 05:20:31 +0000 | [diff] [blame] | 156 | |
| 157 | ret = xstrdup(buf); |
| 158 | memset(buf, 'x', sizeof buf); |
| 159 | return ret; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 160 | } |
Darren Tucker | ce327b6 | 2004-11-05 20:38:03 +1100 | [diff] [blame] | 161 | |
| 162 | int |
| 163 | ask_permission(const char *fmt, ...) |
| 164 | { |
| 165 | va_list args; |
| 166 | char *p, prompt[1024]; |
| 167 | int allowed = 0; |
| 168 | |
| 169 | va_start(args, fmt); |
| 170 | vsnprintf(prompt, sizeof(prompt), fmt, args); |
| 171 | va_end(args); |
| 172 | |
| 173 | p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); |
| 174 | if (p != NULL) { |
| 175 | /* |
| 176 | * Accept empty responses and responses consisting |
| 177 | * of the word "yes" as affirmative. |
| 178 | */ |
| 179 | if (*p == '\0' || *p == '\n' || |
| 180 | strcasecmp(p, "yes") == 0) |
| 181 | allowed = 1; |
| 182 | xfree(p); |
| 183 | } |
| 184 | |
| 185 | return (allowed); |
| 186 | } |