crypto/openssh-4/auth2-none.c

   1 /* $OpenBSD: auth2-none.c,v 1.13 2006/08/05 07:52:52 dtucker Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   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  *
  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.
  24  */
  25
  26 #include "includes.h"
  27
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <sys/uio.h>
  31
  32 #include <fcntl.h>
  33 #include <stdarg.h>
  34 #include <unistd.h>
  35
  36 #include "xmalloc.h"
  37 #include "key.h"
  38 #include "hostfile.h"
  39 #include "auth.h"
  40 #include "packet.h"
  41 #include "log.h"
  42 #include "buffer.h"
  43 #include "servconf.h"
  44 #include "atomicio.h"
  45 #include "compat.h"
  46 #include "ssh2.h"
  47 #ifdef GSSAPI
  48 #include "ssh-gss.h"
  49 #endif
  50 #include "monitor_wrap.h"
  51
  52 /* import */
  53 extern ServerOptions options;
  54
  55 /* "none" is allowed only one time */
  56 static int none_enabled = 1;
  57
  58 char *
  59 auth2_read_banner(void)
  60 {
  61         struct stat st;
  62         char *banner = NULL;
  63         size_t len, n;
  64         int fd;
  65
  66         if ((fd = open(options.banner, O_RDONLY)) == -1)
  67                 return (NULL);
  68         if (fstat(fd, &st) == -1) {
  69                 close(fd);
  70                 return (NULL);
  71         }
  72         if (st.st_size > 1*1024*1024) {
  73                 close(fd);
  74                 return (NULL);
  75         }
  76
  77         len = (size_t)st.st_size;               /* truncate */
  78         banner = xmalloc(len + 1);
  79         n = atomicio(read, fd, banner, len);
  80         close(fd);
  81
  82         if (n != len) {
  83                 xfree(banner);
  84                 return (NULL);
  85         }
  86         banner[n] = '\0';
  87
  88         return (banner);
  89 }
  90
  91 void
  92 userauth_send_banner(const char *msg)
  93 {
  94         if (datafellows & SSH_BUG_BANNER)
  95                 return;
  96
  97         packet_start(SSH2_MSG_USERAUTH_BANNER);
  98         packet_put_cstring(msg);
  99         packet_put_cstring("");         /* language, unused */
 100         packet_send();
 101         debug("%s: sent", __func__);
 102 }
 103
 104 static void
 105 userauth_banner(void)
 106 {
 107         char *banner = NULL;
 108
 109         if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
 110                 return;
 111
 112         if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
 113                 goto done;
 114         userauth_send_banner(banner);
 115
 116 done:
 117         if (banner)
 118                 xfree(banner);
 119 }
 120
 121 static int
 122 userauth_none(Authctxt *authctxt)
 123 {
 124         none_enabled = 0;
 125         packet_check_eom();
 126         userauth_banner();
 127 #ifdef HAVE_CYGWIN
 128         if (check_nt_auth(1, authctxt->pw) == 0)
 129                 return (0);
 130 #endif
 131         if (options.password_authentication)
 132                 return (PRIVSEP(auth_password(authctxt, "")));
 133         return (0);
 134 }
 135
 136 Authmethod method_none = {
 137         "none",
 138         userauth_none,
 139         &none_enabled
 140 };