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