Annotation of src/usr.bin/ssh/readpass.c, Revision 1.46
1.46 ! stevesk 1: /* $OpenBSD: readpass.c,v 1.45 2006/07/26 13:57:17 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>
1.46 ! stevesk 36: #include <stdio.h>
1.45 stevesk 37: #include <stdlib.h>
1.44 stevesk 38: #include <string.h>
1.43 stevesk 39: #include <unistd.h>
1.1 deraadt 40:
41: #include "xmalloc.h"
1.29 djm 42: #include "misc.h"
1.15 markus 43: #include "pathnames.h"
44: #include "log.h"
45: #include "ssh.h"
1.38 markus 46: #include "uidswap.h"
1.15 markus 47:
1.18 itojun 48: static char *
1.16 mouring 49: ssh_askpass(char *askpass, const char *msg)
1.15 markus 50: {
51: pid_t pid;
52: size_t len;
1.23 markus 53: char *pass;
1.24 djm 54: int p[2], status, ret;
1.15 markus 55: char buf[1024];
56:
57: if (fflush(stdout) != 0)
58: error("ssh_askpass: fflush: %s", strerror(errno));
59: if (askpass == NULL)
60: fatal("internal error: askpass undefined");
1.21 markus 61: if (pipe(p) < 0) {
62: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 63: return NULL;
1.21 markus 64: }
65: if ((pid = fork()) < 0) {
66: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 67: return NULL;
1.21 markus 68: }
1.15 markus 69: if (pid == 0) {
1.39 markus 70: permanently_drop_suid(getuid());
1.15 markus 71: close(p[0]);
72: if (dup2(p[1], STDOUT_FILENO) < 0)
73: fatal("ssh_askpass: dup2: %s", strerror(errno));
74: execlp(askpass, askpass, msg, (char *) 0);
75: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
76: }
77: close(p[1]);
1.24 djm 78:
79: len = ret = 0;
80: do {
81: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
82: if (ret == -1 && errno == EINTR)
83: continue;
84: if (ret <= 0)
85: break;
86: len += ret;
87: } while (sizeof(buf) - 1 - len > 0);
88: buf[len] = '\0';
89:
1.15 markus 90: close(p[0]);
91: while (waitpid(pid, &status, 0) < 0)
92: if (errno != EINTR)
93: break;
1.24 djm 94:
1.28 markus 95: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
96: memset(buf, 0, sizeof(buf));
97: return NULL;
98: }
99:
1.23 markus 100: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 101: pass = xstrdup(buf);
102: memset(buf, 0, sizeof(buf));
103: return pass;
104: }
105:
1.7 markus 106: /*
1.19 markus 107: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
108: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
109: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
110: * tty is available
1.12 markus 111: */
1.5 markus 112: char *
1.19 markus 113: read_passphrase(const char *prompt, int flags)
1.1 deraadt 114: {
1.19 markus 115: char *askpass = NULL, *ret, buf[1024];
116: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 117:
1.19 markus 118: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 119: if (flags & RP_USE_ASKPASS)
120: use_askpass = 1;
121: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 122: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 123: debug("read_passphrase: stdin is not a tty");
1.15 markus 124: use_askpass = 1;
1.33 markus 125: }
1.15 markus 126: } else {
1.19 markus 127: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 128: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 129: if (ttyfd >= 0)
130: close(ttyfd);
1.32 dtucker 131: else {
132: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
133: strerror(errno));
1.15 markus 134: use_askpass = 1;
1.32 dtucker 135: }
1.15 markus 136: }
1.30 djm 137:
138: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
139: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 140:
141: if (use_askpass && getenv("DISPLAY")) {
142: if (getenv(SSH_ASKPASS_ENV))
143: askpass = getenv(SSH_ASKPASS_ENV);
144: else
145: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 146: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
147: if (!(flags & RP_ALLOW_EOF))
148: return xstrdup("");
149: return ret;
1.15 markus 150: }
151:
1.27 markus 152: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
153: if (flags & RP_ALLOW_EOF)
154: return NULL;
1.20 markus 155: return xstrdup("");
1.27 markus 156: }
1.19 markus 157:
158: ret = xstrdup(buf);
159: memset(buf, 'x', sizeof buf);
160: return ret;
1.31 djm 161: }
162:
163: int
164: ask_permission(const char *fmt, ...)
165: {
166: va_list args;
167: char *p, prompt[1024];
168: int allowed = 0;
169:
170: va_start(args, fmt);
171: vsnprintf(prompt, sizeof(prompt), fmt, args);
172: va_end(args);
173:
174: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
175: if (p != NULL) {
176: /*
177: * Accept empty responses and responses consisting
178: * of the word "yes" as affirmative.
179: */
180: if (*p == '\0' || *p == '\n' ||
181: strcasecmp(p, "yes") == 0)
182: allowed = 1;
183: xfree(p);
184: }
185:
186: return (allowed);
1.1 deraadt 187: }
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