+/* $OpenBSD: readpass.c,v 1.47 2006/08/03 03:34:42 deraadt Exp $ */
/*
- *
- * readpass.c
- *
- * Author: Tatu Ylonen <ylo@cs.hut.fi>
- *
- * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- * All rights reserved
- *
- * Created: Mon Jul 10 22:08:59 1995 ylo
- *
- * Functions for reading passphrases and passwords.
- *
+ * Copyright (c) 2001 Markus Friedl. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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("$Id$");
+
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#ifdef HAVE_PATHS_H
+# include <paths.h>
+#endif
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
#include "xmalloc.h"
+#include "misc.h"
+#include "pathnames.h"
+#include "log.h"
#include "ssh.h"
+#include "uidswap.h"
-/* Saved old terminal mode for read_passphrase. */
-static struct termios saved_tio;
+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];
-/* Old interrupt signal handler for read_passphrase. */
-static void (*old_handler) (int sig) = NULL;
+ 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 NULL;
+ }
+ if ((pid = fork()) < 0) {
+ error("ssh_askpass: fork: %s", strerror(errno));
+ return NULL;
+ }
+ if (pid == 0) {
+ permanently_drop_suid(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]);
-/* Interrupt signal handler for read_passphrase. */
+ 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';
-void
-intr_handler(int sig)
-{
- /* Restore terminal modes. */
- tcsetattr(fileno(stdin), TCSANOW, &saved_tio);
- /* Restore the old signal handler. */
- signal(sig, old_handler);
- /* Resend the signal, with the old handler. */
- kill(getpid(), sig);
-}
+ close(p[0]);
+ while (waitpid(pid, &status, 0) < 0)
+ if (errno != EINTR)
+ break;
-/* Reads a passphrase from /dev/tty with echo turned off. Returns the
- passphrase (allocated with xmalloc). Exits if EOF is encountered.
- The passphrase if read from stdin if from_stdin is true (as is the
- case with ssh-keygen). */
+ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+ memset(buf, 0, sizeof(buf));
+ return NULL;
+ }
+ 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 from_stdin)
+read_passphrase(const char *prompt, int flags)
{
- char buf[1024], *cp;
- struct termios tio;
- FILE *f;
-
- if (from_stdin)
- f = stdin;
- else {
- /* Read the passphrase from /dev/tty to make it possible
- to ask it even when stdin has been redirected. */
- f = fopen("/dev/tty", "r");
- if (!f) {
- /* No controlling terminal and no DISPLAY. Nowhere to read. */
- fprintf(stderr, "You have no controlling tty and no DISPLAY. Cannot read passphrase.\n");
- exit(1);
+ 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_USE_ASKPASS)
+ use_askpass = 1;
+ else if (flags & RP_ALLOW_STDIN) {
+ if (!isatty(STDIN_FILENO)) {
+ debug("read_passphrase: stdin is not a tty");
+ use_askpass = 1;
+ }
+ } else {
+ rppflags |= RPP_REQUIRE_TTY;
+ ttyfd = open(_PATH_TTY, O_RDWR);
+ if (ttyfd >= 0)
+ close(ttyfd);
+ else {
+ debug("read_passphrase: can't open %s: %s", _PATH_TTY,
+ strerror(errno));
+ use_askpass = 1;
}
}
- /* Display the prompt (on stderr because stdout might be redirected). */
- fflush(stdout);
- fprintf(stderr, "%s", prompt);
- fflush(stderr);
-
- /* Get terminal modes. */
- tcgetattr(fileno(f), &tio);
- saved_tio = tio;
- /* Save signal handler and set the new handler. */
- old_handler = signal(SIGINT, intr_handler);
-
- /* Set new terminal modes disabling all echo. */
- tio.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);
- tcsetattr(fileno(f), TCSANOW, &tio);
-
- /* Read the passphrase from the terminal. */
- if (fgets(buf, sizeof(buf), f) == NULL) {
- /* Got EOF. Just exit. */
- /* Restore terminal modes. */
- tcsetattr(fileno(f), TCSANOW, &saved_tio);
- /* Restore the signal handler. */
- signal(SIGINT, old_handler);
- /* Print a newline (the prompt probably didn\'t have one). */
- fprintf(stderr, "\n");
- /* Close the file. */
- if (f != stdin)
- fclose(f);
- exit(1);
+ if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
+ return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
+
+ if (use_askpass && getenv("DISPLAY")) {
+ if (getenv(SSH_ASKPASS_ENV))
+ askpass = getenv(SSH_ASKPASS_ENV);
+ else
+ askpass = _PATH_SSH_ASKPASS_DEFAULT;
+ if ((ret = ssh_askpass(askpass, prompt)) == NULL)
+ if (!(flags & RP_ALLOW_EOF))
+ return xstrdup("");
+ return ret;
}
- /* Restore terminal modes. */
- tcsetattr(fileno(f), TCSANOW, &saved_tio);
- /* Restore the signal handler. */
- (void) signal(SIGINT, old_handler);
- /* Remove newline from the passphrase. */
- if (strchr(buf, '\n'))
- *strchr(buf, '\n') = 0;
- /* Allocate a copy of the passphrase. */
- cp = xstrdup(buf);
- /* Clear the buffer so we don\'t leave copies of the passphrase
- laying around. */
- memset(buf, 0, sizeof(buf));
- /* Print a newline since the prompt probably didn\'t have one. */
- fprintf(stderr, "\n");
- /* Close the file. */
- if (f != stdin)
- fclose(f);
- return cp;
+
+ if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
+ if (flags & RP_ALLOW_EOF)
+ return NULL;
+ return xstrdup("");
+ }
+
+ ret = xstrdup(buf);
+ memset(buf, 'x', sizeof buf);
+ return ret;
+}
+
+int
+ask_permission(const char *fmt, ...)
+{
+ va_list args;
+ char *p, prompt[1024];
+ int allowed = 0;
+
+ va_start(args, fmt);
+ vsnprintf(prompt, sizeof(prompt), fmt, args);
+ va_end(args);
+
+ p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
+ if (p != NULL) {
+ /*
+ * Accept empty responses and responses consisting
+ * of the word "yes" as affirmative.
+ */
+ if (*p == '\0' || *p == '\n' ||
+ strcasecmp(p, "yes") == 0)
+ allowed = 1;
+ xfree(p);
+ }
+
+ return (allowed);
}
andersk / openssh.git / blobdiff