Annotation of src/usr.bin/ssh/readpass.c, Revision 1.38
1.38 ! markus 1: /* $OpenBSD: readpass.c,v 1.37 2006/03/25 13:17:02 djm 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:
1.34 stevesk 31: #include <paths.h>
1.19 markus 32: #include <readpassphrase.h>
1.1 deraadt 33:
34: #include "xmalloc.h"
1.29 djm 35: #include "misc.h"
1.15 markus 36: #include "pathnames.h"
37: #include "log.h"
38: #include "ssh.h"
1.38 ! markus 39: #include "uidswap.h"
1.15 markus 40:
1.18 itojun 41: static char *
1.16 mouring 42: ssh_askpass(char *askpass, const char *msg)
1.15 markus 43: {
44: pid_t pid;
45: size_t len;
1.23 markus 46: char *pass;
1.24 djm 47: int p[2], status, ret;
1.15 markus 48: char buf[1024];
49:
50: if (fflush(stdout) != 0)
51: error("ssh_askpass: fflush: %s", strerror(errno));
52: if (askpass == NULL)
53: fatal("internal error: askpass undefined");
1.21 markus 54: if (pipe(p) < 0) {
55: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 56: return NULL;
1.21 markus 57: }
58: if ((pid = fork()) < 0) {
59: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 60: return NULL;
1.21 markus 61: }
1.15 markus 62: if (pid == 0) {
1.38 ! markus 63: permanently_set_uid(getpwuid(getuid()));
1.15 markus 64: close(p[0]);
65: if (dup2(p[1], STDOUT_FILENO) < 0)
66: fatal("ssh_askpass: dup2: %s", strerror(errno));
67: execlp(askpass, askpass, msg, (char *) 0);
68: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
69: }
70: close(p[1]);
1.24 djm 71:
72: len = ret = 0;
73: do {
74: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
75: if (ret == -1 && errno == EINTR)
76: continue;
77: if (ret <= 0)
78: break;
79: len += ret;
80: } while (sizeof(buf) - 1 - len > 0);
81: buf[len] = '\0';
82:
1.15 markus 83: close(p[0]);
84: while (waitpid(pid, &status, 0) < 0)
85: if (errno != EINTR)
86: break;
1.24 djm 87:
1.28 markus 88: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
89: memset(buf, 0, sizeof(buf));
90: return NULL;
91: }
92:
1.23 markus 93: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 94: pass = xstrdup(buf);
95: memset(buf, 0, sizeof(buf));
96: return pass;
97: }
98:
1.7 markus 99: /*
1.19 markus 100: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
101: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
102: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
103: * tty is available
1.12 markus 104: */
1.5 markus 105: char *
1.19 markus 106: read_passphrase(const char *prompt, int flags)
1.1 deraadt 107: {
1.19 markus 108: char *askpass = NULL, *ret, buf[1024];
109: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 110:
1.19 markus 111: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 112: if (flags & RP_USE_ASKPASS)
113: use_askpass = 1;
114: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 115: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 116: debug("read_passphrase: stdin is not a tty");
1.15 markus 117: use_askpass = 1;
1.33 markus 118: }
1.15 markus 119: } else {
1.19 markus 120: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 121: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 122: if (ttyfd >= 0)
123: close(ttyfd);
1.32 dtucker 124: else {
125: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
126: strerror(errno));
1.15 markus 127: use_askpass = 1;
1.32 dtucker 128: }
1.15 markus 129: }
1.30 djm 130:
131: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
132: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 133:
134: if (use_askpass && getenv("DISPLAY")) {
135: if (getenv(SSH_ASKPASS_ENV))
136: askpass = getenv(SSH_ASKPASS_ENV);
137: else
138: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 139: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
140: if (!(flags & RP_ALLOW_EOF))
141: return xstrdup("");
142: return ret;
1.15 markus 143: }
144:
1.27 markus 145: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
146: if (flags & RP_ALLOW_EOF)
147: return NULL;
1.20 markus 148: return xstrdup("");
1.27 markus 149: }
1.19 markus 150:
151: ret = xstrdup(buf);
152: memset(buf, 'x', sizeof buf);
153: return ret;
1.31 djm 154: }
155:
156: int
157: ask_permission(const char *fmt, ...)
158: {
159: va_list args;
160: char *p, prompt[1024];
161: int allowed = 0;
162:
163: va_start(args, fmt);
164: vsnprintf(prompt, sizeof(prompt), fmt, args);
165: va_end(args);
166:
167: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
168: if (p != NULL) {
169: /*
170: * Accept empty responses and responses consisting
171: * of the word "yes" as affirmative.
172: */
173: if (*p == '\0' || *p == '\n' ||
174: strcasecmp(p, "yes") == 0)
175: allowed = 1;
176: xfree(p);
177: }
178:
179: return (allowed);
1.1 deraadt 180: }
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