Annotation of src/usr.bin/ssh/readpass.c, Revision 1.36
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"
1.35 stevesk 26:
27: #include <sys/types.h>
28: #include <sys/wait.h>
1.19 markus 29:
1.34 stevesk 30: #include <paths.h>
1.19 markus 31: #include <readpassphrase.h>
1.1 deraadt 32:
33: #include "xmalloc.h"
1.29 djm 34: #include "misc.h"
1.15 markus 35: #include "pathnames.h"
36: #include "log.h"
37: #include "ssh.h"
38:
1.18 itojun 39: static char *
1.16 mouring 40: ssh_askpass(char *askpass, const char *msg)
1.15 markus 41: {
42: pid_t pid;
43: size_t len;
1.23 markus 44: char *pass;
1.24 djm 45: int p[2], status, ret;
1.15 markus 46: char buf[1024];
47:
48: if (fflush(stdout) != 0)
49: error("ssh_askpass: fflush: %s", strerror(errno));
50: if (askpass == NULL)
51: fatal("internal error: askpass undefined");
1.21 markus 52: if (pipe(p) < 0) {
53: error("ssh_askpass: pipe: %s", strerror(errno));
1.28 markus 54: return NULL;
1.21 markus 55: }
56: if ((pid = fork()) < 0) {
57: error("ssh_askpass: fork: %s", strerror(errno));
1.28 markus 58: return NULL;
1.21 markus 59: }
1.15 markus 60: if (pid == 0) {
61: seteuid(getuid());
62: setuid(getuid());
63: close(p[0]);
64: if (dup2(p[1], STDOUT_FILENO) < 0)
65: fatal("ssh_askpass: dup2: %s", strerror(errno));
66: execlp(askpass, askpass, msg, (char *) 0);
67: fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
68: }
69: close(p[1]);
1.24 djm 70:
71: len = ret = 0;
72: do {
73: ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
74: if (ret == -1 && errno == EINTR)
75: continue;
76: if (ret <= 0)
77: break;
78: len += ret;
79: } while (sizeof(buf) - 1 - len > 0);
80: buf[len] = '\0';
81:
1.15 markus 82: close(p[0]);
83: while (waitpid(pid, &status, 0) < 0)
84: if (errno != EINTR)
85: break;
1.24 djm 86:
1.28 markus 87: if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
88: memset(buf, 0, sizeof(buf));
89: return NULL;
90: }
91:
1.23 markus 92: buf[strcspn(buf, "\r\n")] = '\0';
1.15 markus 93: pass = xstrdup(buf);
94: memset(buf, 0, sizeof(buf));
95: return pass;
96: }
97:
1.7 markus 98: /*
1.19 markus 99: * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
100: * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
101: * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
102: * tty is available
1.12 markus 103: */
1.5 markus 104: char *
1.19 markus 105: read_passphrase(const char *prompt, int flags)
1.1 deraadt 106: {
1.19 markus 107: char *askpass = NULL, *ret, buf[1024];
108: int rppflags, use_askpass = 0, ttyfd;
1.15 markus 109:
1.19 markus 110: rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1.30 djm 111: if (flags & RP_USE_ASKPASS)
112: use_askpass = 1;
113: else if (flags & RP_ALLOW_STDIN) {
1.33 markus 114: if (!isatty(STDIN_FILENO)) {
1.32 dtucker 115: debug("read_passphrase: stdin is not a tty");
1.15 markus 116: use_askpass = 1;
1.33 markus 117: }
1.15 markus 118: } else {
1.19 markus 119: rppflags |= RPP_REQUIRE_TTY;
1.25 markus 120: ttyfd = open(_PATH_TTY, O_RDWR);
1.15 markus 121: if (ttyfd >= 0)
122: close(ttyfd);
1.32 dtucker 123: else {
124: debug("read_passphrase: can't open %s: %s", _PATH_TTY,
125: strerror(errno));
1.15 markus 126: use_askpass = 1;
1.32 dtucker 127: }
1.15 markus 128: }
1.30 djm 129:
130: if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
131: return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
1.15 markus 132:
133: if (use_askpass && getenv("DISPLAY")) {
134: if (getenv(SSH_ASKPASS_ENV))
135: askpass = getenv(SSH_ASKPASS_ENV);
136: else
137: askpass = _PATH_SSH_ASKPASS_DEFAULT;
1.28 markus 138: if ((ret = ssh_askpass(askpass, prompt)) == NULL)
139: if (!(flags & RP_ALLOW_EOF))
140: return xstrdup("");
141: return ret;
1.15 markus 142: }
143:
1.27 markus 144: if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
145: if (flags & RP_ALLOW_EOF)
146: return NULL;
1.20 markus 147: return xstrdup("");
1.27 markus 148: }
1.19 markus 149:
150: ret = xstrdup(buf);
151: memset(buf, 'x', sizeof buf);
152: return ret;
1.31 djm 153: }
154:
155: int
156: ask_permission(const char *fmt, ...)
157: {
158: va_list args;
159: char *p, prompt[1024];
160: int allowed = 0;
161:
162: va_start(args, fmt);
163: vsnprintf(prompt, sizeof(prompt), fmt, args);
164: va_end(args);
165:
166: p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
167: if (p != NULL) {
168: /*
169: * Accept empty responses and responses consisting
170: * of the word "yes" as affirmative.
171: */
172: if (*p == '\0' || *p == '\n' ||
173: strcasecmp(p, "yes") == 0)
174: allowed = 1;
175: xfree(p);
176: }
177:
178: return (allowed);
1.1 deraadt 179: }
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