Annotation of src/usr.bin/ssh/readpass.c, Revision 1.43
1.43 ! stevesk 1: /* $OpenBSD: readpass.c,v 1.42 2006/07/11 20:07:25 stevesk 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:
1.42 stevesk 31: #include <errno.h>
1.40 stevesk 32: #include <fcntl.h>
1.34 stevesk 33: #include <paths.h>
1.19 markus 34: #include <readpassphrase.h>
1.41 stevesk 35: #include <stdarg.h>
1.43 ! stevesk 36: #include <unistd.h>
1.1 deraadt 37:
38: #include "xmalloc.h"
1.29 djm 39: #include "misc.h"
1.15 markus 40: #include "pathnames.h"
41: #include "log.h"
42: #include "ssh.h"
1.38 markus 43: #include "uidswap.h"
1.15 markus 44:
1.18 itojun 45: static char *
1.16 mouring 46: ssh_askpass(char *askpass, const char *msg)
1.15 markus 47: {
48: pid_t pid;
49: size_t len;
1.23 markus 50: char *pass;
1.24 djm 51: int p[2], status, ret;
1.15 markus 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");
1.21 markus 58: if (pipe(p) < 0) {
59: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 60: return NULL;
1.21 markus 61: }
62: if ((pid = fork()) < 0) {
63: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 64: return NULL;
1.21 markus 65: }
1.15 markus 66: if (pid == 0) {
1.39 markus 67: permanently_drop_suid(getuid());
1.15 markus 68: close(p[0]);
69: if (dup2(p[1], STDOUT_FILENO) < 0)
70: fatal("ssh_askpass: dup2: %s", strerror(errno));
71: execlp(askpass, askpass, msg, (char *) 0);
72: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
73: }
74: close(p[1]);
1.24 djm 75:
76: len = ret = 0;
77: do {
78: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
79: if (ret == -1 && errno == EINTR)
80: continue;
81: if (ret <= 0)
82: break;
83: len += ret;
84: } while (sizeof(buf) - 1 - len > 0);
85: buf[len] = '\0';
86:
1.15 markus 87: close(p[0]);
88: while (waitpid(pid, &status, 0) < 0)
89: if (errno != EINTR)
90: break;
1.24 djm 91:
1.28 markus 92: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
93: memset(buf, 0, sizeof(buf));
94: return NULL;
95: }
96:
1.23 markus 97: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 98: pass = xstrdup(buf);
99: memset(buf, 0, sizeof(buf));
100: return pass;
101: }
102:
1.7 markus 103: /*
1.19 markus 104: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
105: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
106: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
107: * tty is available
1.12 markus 108: */
1.5 markus 109: char *
1.19 markus 110: read_passphrase(const char *prompt, int flags)
1.1 deraadt 111: {
1.19 markus 112: char *askpass = NULL, *ret, buf[1024];
113: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 114:
1.19 markus 115: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 116: if (flags & RP_USE_ASKPASS)
117: use_askpass = 1;
118: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 119: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 120: debug("read_passphrase: stdin is not a tty");
1.15 markus 121: use_askpass = 1;
1.33 markus 122: }
1.15 markus 123: } else {
1.19 markus 124: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 125: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 126: if (ttyfd >= 0)
127: close(ttyfd);
1.32 dtucker 128: else {
129: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
130: strerror(errno));
1.15 markus 131: use_askpass = 1;
1.32 dtucker 132: }
1.15 markus 133: }
1.30 djm 134:
135: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
136: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 137:
138: if (use_askpass && getenv("DISPLAY")) {
139: if (getenv(SSH_ASKPASS_ENV))
140: askpass = getenv(SSH_ASKPASS_ENV);
141: else
142: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 143: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
144: if (!(flags & RP_ALLOW_EOF))
145: return xstrdup("");
146: return ret;
1.15 markus 147: }
148:
1.27 markus 149: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
150: if (flags & RP_ALLOW_EOF)
151: return NULL;
1.20 markus 152: return xstrdup("");
1.27 markus 153: }
1.19 markus 154:
155: ret = xstrdup(buf);
156: memset(buf, 'x', sizeof buf);
157: return ret;
1.31 djm 158: }
159:
160: int
161: ask_permission(const char *fmt, ...)
162: {
163: va_list args;
164: char *p, prompt[1024];
165: int allowed = 0;
166:
167: va_start(args, fmt);
168: vsnprintf(prompt, sizeof(prompt), fmt, args);
169: va_end(args);
170:
171: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
172: if (p != NULL) {
173: /*
174: * Accept empty responses and responses consisting
175: * of the word "yes" as affirmative.
176: */
177: if (*p == '\0' || *p == '\n' ||
178: strcasecmp(p, "yes") == 0)
179: allowed = 1;
180: xfree(p);
181: }
182:
183: return (allowed);
1.1 deraadt 184: }
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