Annotation of src/usr.bin/ssh/readpass.c, Revision 1.40
1.40 ! stevesk 1: /* $OpenBSD: readpass.c,v 1.39 2006/06/08 14:45:49 markus Exp $ */
1.1 deraadt 2: /*
1.26 markus 3: * Copyright (c) 2001 Markus Friedl. All rights reserved.
1.8 deraadt 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: *
1.26 markus 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.
1.6 deraadt 24: */
1.1 deraadt 25:
26: #include "includes.h"
1.35 stevesk 27:
28: #include <sys/types.h>
29: #include <sys/wait.h>
1.19 markus 30:
1.40 ! stevesk 31: #include <fcntl.h>
1.34 stevesk 32: #include <paths.h>
1.19 markus 33: #include <readpassphrase.h>
1.1 deraadt 34:
35: #include "xmalloc.h"
1.29 djm 36: #include "misc.h"
1.15 markus 37: #include "pathnames.h"
38: #include "log.h"
39: #include "ssh.h"
1.38 markus 40: #include "uidswap.h"
1.15 markus 41:
1.18 itojun 42: static char *
1.16 mouring 43: ssh_askpass(char *askpass, const char *msg)
1.15 markus 44: {
45: pid_t pid;
46: size_t len;
1.23 markus 47: char *pass;
1.24 djm 48: int p[2], status, ret;
1.15 markus 49: char buf[1024];
50:
51: if (fflush(stdout) != 0)
52: error("ssh_askpass: fflush: %s", strerror(errno));
53: if (askpass == NULL)
54: fatal("internal error: askpass undefined");
1.21 markus 55: if (pipe(p) < 0) {
56: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 57: return NULL;
1.21 markus 58: }
59: if ((pid = fork()) < 0) {
60: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 61: return NULL;
1.21 markus 62: }
1.15 markus 63: if (pid == 0) {
1.39 markus 64: permanently_drop_suid(getuid());
1.15 markus 65: close(p[0]);
66: if (dup2(p[1], STDOUT_FILENO) < 0)
67: fatal("ssh_askpass: dup2: %s", strerror(errno));
68: execlp(askpass, askpass, msg, (char *) 0);
69: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
70: }
71: close(p[1]);
1.24 djm 72:
73: len = ret = 0;
74: do {
75: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
76: if (ret == -1 && errno == EINTR)
77: continue;
78: if (ret <= 0)
79: break;
80: len += ret;
81: } while (sizeof(buf) - 1 - len > 0);
82: buf[len] = '\0';
83:
1.15 markus 84: close(p[0]);
85: while (waitpid(pid, &status, 0) < 0)
86: if (errno != EINTR)
87: break;
1.24 djm 88:
1.28 markus 89: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
90: memset(buf, 0, sizeof(buf));
91: return NULL;
92: }
93:
1.23 markus 94: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 95: pass = xstrdup(buf);
96: memset(buf, 0, sizeof(buf));
97: return pass;
98: }
99:
1.7 markus 100: /*
1.19 markus 101: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
102: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
103: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
104: * tty is available
1.12 markus 105: */
1.5 markus 106: char *
1.19 markus 107: read_passphrase(const char *prompt, int flags)
1.1 deraadt 108: {
1.19 markus 109: char *askpass = NULL, *ret, buf[1024];
110: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 111:
1.19 markus 112: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 113: if (flags & RP_USE_ASKPASS)
114: use_askpass = 1;
115: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 116: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 117: debug("read_passphrase: stdin is not a tty");
1.15 markus 118: use_askpass = 1;
1.33 markus 119: }
1.15 markus 120: } else {
1.19 markus 121: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 122: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 123: if (ttyfd >= 0)
124: close(ttyfd);
1.32 dtucker 125: else {
126: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
127: strerror(errno));
1.15 markus 128: use_askpass = 1;
1.32 dtucker 129: }
1.15 markus 130: }
1.30 djm 131:
132: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
133: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 134:
135: if (use_askpass && getenv("DISPLAY")) {
136: if (getenv(SSH_ASKPASS_ENV))
137: askpass = getenv(SSH_ASKPASS_ENV);
138: else
139: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 140: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
141: if (!(flags & RP_ALLOW_EOF))
142: return xstrdup("");
143: return ret;
1.15 markus 144: }
145:
1.27 markus 146: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
147: if (flags & RP_ALLOW_EOF)
148: return NULL;
1.20 markus 149: return xstrdup("");
1.27 markus 150: }
1.19 markus 151:
152: ret = xstrdup(buf);
153: memset(buf, 'x', sizeof buf);
154: return ret;
1.31 djm 155: }
156:
157: int
158: ask_permission(const char *fmt, ...)
159: {
160: va_list args;
161: char *p, prompt[1024];
162: int allowed = 0;
163:
164: va_start(args, fmt);
165: vsnprintf(prompt, sizeof(prompt), fmt, args);
166: va_end(args);
167:
168: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
169: if (p != NULL) {
170: /*
171: * Accept empty responses and responses consisting
172: * of the word "yes" as affirmative.
173: */
174: if (*p == '\0' || *p == '\n' ||
175: strcasecmp(p, "yes") == 0)
176: allowed = 1;
177: xfree(p);
178: }
179:
180: return (allowed);
1.1 deraadt 181: }
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