openssh/readpass.c
Damien Miller f451e22e21 - djm@cvs.openbsd.org 2001/12/21 08:53:45
[readpass.c]
     Avoid interruptable passphrase read; ok markus@
2002-01-22 23:05:31 +11:00

137 lines
4.1 KiB
C

/*
* Copyright (c) 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "includes.h"
RCSID("$OpenBSD: readpass.c,v 1.24 2001/12/21 08:53:45 djm Exp $");
#include "xmalloc.h"
#include "readpass.h"
#include "pathnames.h"
#include "log.h"
#include "ssh.h"
static char *
ssh_askpass(char *askpass, const char *msg)
{
pid_t pid;
size_t len;
char *pass;
int p[2], status, ret;
char buf[1024];
if (fflush(stdout) != 0)
error("ssh_askpass: fflush: %s", strerror(errno));
if (askpass == NULL)
fatal("internal error: askpass undefined");
if (pipe(p) < 0) {
error("ssh_askpass: pipe: %s", strerror(errno));
return xstrdup("");
}
if ((pid = fork()) < 0) {
error("ssh_askpass: fork: %s", strerror(errno));
return xstrdup("");
}
if (pid == 0) {
seteuid(getuid());
setuid(getuid());
close(p[0]);
if (dup2(p[1], STDOUT_FILENO) < 0)
fatal("ssh_askpass: dup2: %s", strerror(errno));
execlp(askpass, askpass, msg, (char *) 0);
fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
}
close(p[1]);
len = ret = 0;
do {
ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
if (ret == -1 && errno == EINTR)
continue;
if (ret <= 0)
break;
len += ret;
} while (sizeof(buf) - 1 - len > 0);
buf[len] = '\0';
close(p[0]);
while (waitpid(pid, &status, 0) < 0)
if (errno != EINTR)
break;
buf[strcspn(buf, "\r\n")] = '\0';
pass = xstrdup(buf);
memset(buf, 0, sizeof(buf));
return pass;
}
/*
* Reads a passphrase from /dev/tty with echo turned off/on. Returns the
* passphrase (allocated with xmalloc). Exits if EOF is encountered. If
* RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
* tty is available
*/
char *
read_passphrase(const char *prompt, int flags)
{
char *askpass = NULL, *ret, buf[1024];
int rppflags, use_askpass = 0, ttyfd;
rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
if (flags & RP_ALLOW_STDIN) {
if (!isatty(STDIN_FILENO))
use_askpass = 1;
} else {
rppflags |= RPP_REQUIRE_TTY;
ttyfd = open("/dev/tty", O_RDWR);
if (ttyfd >= 0)
close(ttyfd);
else
use_askpass = 1;
}
if (use_askpass && getenv("DISPLAY")) {
if (getenv(SSH_ASKPASS_ENV))
askpass = getenv(SSH_ASKPASS_ENV);
else
askpass = _PATH_SSH_ASKPASS_DEFAULT;
return ssh_askpass(askpass, prompt);
}
if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL)
return xstrdup("");
ret = xstrdup(buf);
memset(buf, 'x', sizeof buf);
return ret;
}