1 /* $OpenBSD: auth2-none.c,v 1.14 2007/08/23 03:22:16 djm 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 <sys/types.h> 27 #include <sys/stat.h> 28 #include <sys/uio.h> 29 30 #include <fcntl.h> 31 #include <unistd.h> 32 #include <string.h> 33 34 #include "xmalloc.h" 35 #include "key.h" 36 #include "hostfile.h" 37 #include "auth.h" 38 #include "packet.h" 39 #include "log.h" 40 #include "buffer.h" 41 #include "servconf.h" 42 #include "atomicio.h" 43 #include "compat.h" 44 #include "ssh2.h" 45 #ifdef GSSAPI 46 #include "ssh-gss.h" 47 #endif 48 #include "monitor_wrap.h" 49 50 /* import */ 51 extern ServerOptions options; 52 53 /* "none" is allowed only one time */ 54 static int none_enabled = 1; 55 56 char * 57 auth2_read_banner(void) 58 { 59 struct stat st; 60 char *banner = NULL; 61 size_t len, n; 62 int fd; 63 64 if ((fd = open(options.banner, O_RDONLY)) == -1) 65 return (NULL); 66 if (fstat(fd, &st) == -1) { 67 close(fd); 68 return (NULL); 69 } 70 if (st.st_size > 1*1024*1024) { 71 close(fd); 72 return (NULL); 73 } 74 75 len = (size_t)st.st_size; /* truncate */ 76 banner = xmalloc(len + 1); 77 n = atomicio(read, fd, banner, len); 78 close(fd); 79 80 if (n != len) { 81 xfree(banner); 82 return (NULL); 83 } 84 banner[n] = '\0'; 85 86 return (banner); 87 } 88 89 static void 90 userauth_banner(void) 91 { 92 char *banner = NULL; 93 94 if (options.banner == NULL || 95 strcasecmp(options.banner, "none") == 0 || 96 (datafellows & SSH_BUG_BANNER) != 0) 97 return; 98 99 if ((banner = PRIVSEP(auth2_read_banner())) == NULL) 100 goto done; 101 102 packet_start(SSH2_MSG_USERAUTH_BANNER); 103 packet_put_cstring(banner); 104 packet_put_cstring(""); /* language, unused */ 105 packet_send(); 106 debug("userauth_banner: sent"); 107 done: 108 if (banner) 109 xfree(banner); 110 } 111 112 static int 113 userauth_none(Authctxt *authctxt) 114 { 115 none_enabled = 0; 116 packet_check_eom(); 117 userauth_banner(); 118 if (options.password_authentication) 119 return (PRIVSEP(auth_password(authctxt, ""))); 120 return (0); 121 } 122 123 Authmethod method_none = { 124 "none", 125 userauth_none, 126 &none_enabled 127 }; 128