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