Annotation of src/usr.bin/ssh/readpass.c, Revision 1.32
1.1 deraadt 1: /*
1.26 markus 2: * Copyright (c) 2001 Markus Friedl. All rights reserved.
1.8 deraadt 3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
1.26 markus 13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.6 deraadt 23: */
1.1 deraadt 24:
25: #include "includes.h"
1.32 ! dtucker 26: RCSID("$OpenBSD: readpass.c,v 1.31 2004/10/29 22:53:56 djm Exp $");
1.19 markus 27:
28: #include <readpassphrase.h>
1.1 deraadt 29:
30: #include "xmalloc.h"
1.29 djm 31: #include "misc.h"
1.15 markus 32: #include "pathnames.h"
33: #include "log.h"
34: #include "ssh.h"
35:
1.18 itojun 36: static char *
1.16 mouring 37: ssh_askpass(char *askpass, const char *msg)
1.15 markus 38: {
39: pid_t pid;
40: size_t len;
1.23 markus 41: char *pass;
1.24 djm 42: int p[2], status, ret;
1.15 markus 43: char buf[1024];
44:
45: if (fflush(stdout) != 0)
46: error("ssh_askpass: fflush: %s", strerror(errno));
47: if (askpass == NULL)
48: fatal("internal error: askpass undefined");
1.21 markus 49: if (pipe(p) < 0) {
50: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 51: return NULL;
1.21 markus 52: }
53: if ((pid = fork()) < 0) {
54: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 55: return NULL;
1.21 markus 56: }
1.15 markus 57: if (pid == 0) {
58: seteuid(getuid());
59: setuid(getuid());
60: close(p[0]);
61: if (dup2(p[1], STDOUT_FILENO) < 0)
62: fatal("ssh_askpass: dup2: %s", strerror(errno));
63: execlp(askpass, askpass, msg, (char *) 0);
64: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
65: }
66: close(p[1]);
1.24 djm 67:
68: len = ret = 0;
69: do {
70: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
71: if (ret == -1 && errno == EINTR)
72: continue;
73: if (ret <= 0)
74: break;
75: len += ret;
76: } while (sizeof(buf) - 1 - len > 0);
77: buf[len] = '\0';
78:
1.15 markus 79: close(p[0]);
80: while (waitpid(pid, &status, 0) < 0)
81: if (errno != EINTR)
82: break;
1.24 djm 83:
1.28 markus 84: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
85: memset(buf, 0, sizeof(buf));
86: return NULL;
87: }
88:
1.23 markus 89: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 90: pass = xstrdup(buf);
91: memset(buf, 0, sizeof(buf));
92: return pass;
93: }
94:
1.7 markus 95: /*
1.19 markus 96: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
97: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
98: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
99: * tty is available
1.12 markus 100: */
1.5 markus 101: char *
1.19 markus 102: read_passphrase(const char *prompt, int flags)
1.1 deraadt 103: {
1.19 markus 104: char *askpass = NULL, *ret, buf[1024];
105: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 106:
1.19 markus 107: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 108: if (flags & RP_USE_ASKPASS)
109: use_askpass = 1;
110: else if (flags & RP_ALLOW_STDIN) {
1.15 markus 111: if (!isatty(STDIN_FILENO))
1.32 ! dtucker 112: debug("read_passphrase: stdin is not a tty");
1.15 markus 113: use_askpass = 1;
114: } else {
1.19 markus 115: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 116: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 117: if (ttyfd >= 0)
118: close(ttyfd);
1.32 ! dtucker 119: else {
! 120: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
! 121: strerror(errno));
1.15 markus 122: use_askpass = 1;
1.32 ! dtucker 123: }
1.15 markus 124: }
1.30 djm 125:
126: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
127: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 128:
129: if (use_askpass && getenv("DISPLAY")) {
130: if (getenv(SSH_ASKPASS_ENV))
131: askpass = getenv(SSH_ASKPASS_ENV);
132: else
133: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 134: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
135: if (!(flags & RP_ALLOW_EOF))
136: return xstrdup("");
137: return ret;
1.15 markus 138: }
139:
1.27 markus 140: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
141: if (flags & RP_ALLOW_EOF)
142: return NULL;
1.20 markus 143: return xstrdup("");
1.27 markus 144: }
1.19 markus 145:
146: ret = xstrdup(buf);
147: memset(buf, 'x', sizeof buf);
148: return ret;
1.31 djm 149: }
150:
151: int
152: ask_permission(const char *fmt, ...)
153: {
154: va_list args;
155: char *p, prompt[1024];
156: int allowed = 0;
157:
158: va_start(args, fmt);
159: vsnprintf(prompt, sizeof(prompt), fmt, args);
160: va_end(args);
161:
162: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
163: if (p != NULL) {
164: /*
165: * Accept empty responses and responses consisting
166: * of the word "yes" as affirmative.
167: */
168: if (*p == '\0' || *p == '\n' ||
169: strcasecmp(p, "yes") == 0)
170: allowed = 1;
171: xfree(p);
172: }
173:
174: return (allowed);
1.1 deraadt 175: }