- djm@cvs.openbsd.org 2010/01/30 02:54:53

[openssh.git] / readpass.c

diff --git a/readpass.c b/readpass.c
index b4421ade04dccb4b9eba43b06d54b823c3ed44cd..bd144c2e39177a15f8fd21535782b9e141de6d8e 100644 (file)
--- a/readpass.c
+++ b/readpass.c
@@ -1,3 +1,4 @@
+/* $OpenBSD: readpass.c,v 1.47 2006/08/03 03:34:42 deraadt Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -23,13 +24,27 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: readpass.c,v 1.26 2002/02/13 00:39:15 markus Exp $");
+
+#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 "readpass.h"
+#include "misc.h"
 #include "pathnames.h"
 #include "log.h"
 #include "ssh.h"
+#include "uidswap.h"
 
 static char *
 ssh_askpass(char *askpass, const char *msg)
@@ -46,15 +61,14 @@ ssh_askpass(char *askpass, const char *msg)
                fatal("internal error: askpass undefined");
        if (pipe(p) < 0) {
                error("ssh_askpass: pipe: %s", strerror(errno));
-               return xstrdup("");
+               return NULL;
        }
        if ((pid = fork()) < 0) {
                error("ssh_askpass: fork: %s", strerror(errno));
-               return xstrdup("");
+               return NULL;
        }
        if (pid == 0) {
-               seteuid(getuid());
-               setuid(getuid());
+               permanently_drop_suid(getuid());
                close(p[0]);
                if (dup2(p[1], STDOUT_FILENO) < 0)
                        fatal("ssh_askpass: dup2: %s", strerror(errno));
@@ -79,6 +93,11 @@ ssh_askpass(char *askpass, const char *msg)
                if (errno != EINTR)
                        break;
 
+       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));
@@ -98,30 +117,72 @@ read_passphrase(const char *prompt, int flags)
        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))
+       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
+               else {
+                       debug("read_passphrase: can't open %s: %s", _PATH_TTY,
+                           strerror(errno));
                        use_askpass = 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;
-               return ssh_askpass(askpass, prompt);
+               if ((ret = ssh_askpass(askpass, prompt)) == NULL)
+                       if (!(flags & RP_ALLOW_EOF))
+                               return xstrdup("");
+               return ret;
        }
 
-       if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL)
+       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);
+}