1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * Author: Tatu Ylonen <ylo@cs.hut.fi> 3*0Sstevel@tonic-gate * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4*0Sstevel@tonic-gate * All rights reserved 5*0Sstevel@tonic-gate * Functions for manipulating the known hosts files. 6*0Sstevel@tonic-gate * 7*0Sstevel@tonic-gate * As far as I am concerned, the code I have written for this software 8*0Sstevel@tonic-gate * can be used freely for any purpose. Any derived versions of this 9*0Sstevel@tonic-gate * software must be clearly marked as such, and if the derived work is 10*0Sstevel@tonic-gate * incompatible with the protocol description in the RFC file, it must be 11*0Sstevel@tonic-gate * called by a name other than "ssh" or "Secure Shell". 12*0Sstevel@tonic-gate * 13*0Sstevel@tonic-gate * 14*0Sstevel@tonic-gate * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 15*0Sstevel@tonic-gate * Copyright (c) 1999 Niels Provos. All rights reserved. 16*0Sstevel@tonic-gate * 17*0Sstevel@tonic-gate * Redistribution and use in source and binary forms, with or without 18*0Sstevel@tonic-gate * modification, are permitted provided that the following conditions 19*0Sstevel@tonic-gate * are met: 20*0Sstevel@tonic-gate * 1. Redistributions of source code must retain the above copyright 21*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer. 22*0Sstevel@tonic-gate * 2. Redistributions in binary form must reproduce the above copyright 23*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer in the 24*0Sstevel@tonic-gate * documentation and/or other materials provided with the distribution. 25*0Sstevel@tonic-gate * 26*0Sstevel@tonic-gate * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27*0Sstevel@tonic-gate * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28*0Sstevel@tonic-gate * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29*0Sstevel@tonic-gate * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30*0Sstevel@tonic-gate * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31*0Sstevel@tonic-gate * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32*0Sstevel@tonic-gate * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33*0Sstevel@tonic-gate * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34*0Sstevel@tonic-gate * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35*0Sstevel@tonic-gate * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36*0Sstevel@tonic-gate */ 37*0Sstevel@tonic-gate 38*0Sstevel@tonic-gate #include "includes.h" 39*0Sstevel@tonic-gate RCSID("$OpenBSD: hostfile.c,v 1.30 2002/07/24 16:11:18 markus Exp $"); 40*0Sstevel@tonic-gate 41*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 42*0Sstevel@tonic-gate 43*0Sstevel@tonic-gate #include "packet.h" 44*0Sstevel@tonic-gate #include "match.h" 45*0Sstevel@tonic-gate #include "key.h" 46*0Sstevel@tonic-gate #include "hostfile.h" 47*0Sstevel@tonic-gate #include "log.h" 48*0Sstevel@tonic-gate 49*0Sstevel@tonic-gate /* 50*0Sstevel@tonic-gate * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 51*0Sstevel@tonic-gate * pointer over the key. Skips any whitespace at the beginning and at end. 52*0Sstevel@tonic-gate */ 53*0Sstevel@tonic-gate 54*0Sstevel@tonic-gate int 55*0Sstevel@tonic-gate hostfile_read_key(char **cpp, u_int *bitsp, Key *ret) 56*0Sstevel@tonic-gate { 57*0Sstevel@tonic-gate char *cp; 58*0Sstevel@tonic-gate 59*0Sstevel@tonic-gate /* Skip leading whitespace. */ 60*0Sstevel@tonic-gate for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 61*0Sstevel@tonic-gate ; 62*0Sstevel@tonic-gate 63*0Sstevel@tonic-gate if (key_read(ret, &cp) != 1) 64*0Sstevel@tonic-gate return 0; 65*0Sstevel@tonic-gate 66*0Sstevel@tonic-gate /* Skip trailing whitespace. */ 67*0Sstevel@tonic-gate for (; *cp == ' ' || *cp == '\t'; cp++) 68*0Sstevel@tonic-gate ; 69*0Sstevel@tonic-gate 70*0Sstevel@tonic-gate /* Return results. */ 71*0Sstevel@tonic-gate *cpp = cp; 72*0Sstevel@tonic-gate *bitsp = key_size(ret); 73*0Sstevel@tonic-gate return 1; 74*0Sstevel@tonic-gate } 75*0Sstevel@tonic-gate 76*0Sstevel@tonic-gate static int 77*0Sstevel@tonic-gate hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) 78*0Sstevel@tonic-gate { 79*0Sstevel@tonic-gate if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL) 80*0Sstevel@tonic-gate return 1; 81*0Sstevel@tonic-gate if (bits != BN_num_bits(key->rsa->n)) { 82*0Sstevel@tonic-gate log("Warning: %s, line %d: keysize mismatch for host %s: " 83*0Sstevel@tonic-gate "actual %d vs. announced %d.", 84*0Sstevel@tonic-gate filename, linenum, host, BN_num_bits(key->rsa->n), bits); 85*0Sstevel@tonic-gate log("Warning: replace %d with %d in %s, line %d.", 86*0Sstevel@tonic-gate bits, BN_num_bits(key->rsa->n), filename, linenum); 87*0Sstevel@tonic-gate } 88*0Sstevel@tonic-gate return 1; 89*0Sstevel@tonic-gate } 90*0Sstevel@tonic-gate 91*0Sstevel@tonic-gate /* 92*0Sstevel@tonic-gate * Checks whether the given host (which must be in all lowercase) is already 93*0Sstevel@tonic-gate * in the list of our known hosts. Returns HOST_OK if the host is known and 94*0Sstevel@tonic-gate * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED 95*0Sstevel@tonic-gate * if the host is known but used to have a different host key. 96*0Sstevel@tonic-gate * 97*0Sstevel@tonic-gate * If no 'key' has been specified and a key of type 'keytype' is known 98*0Sstevel@tonic-gate * for the specified host, then HOST_FOUND is returned. 99*0Sstevel@tonic-gate */ 100*0Sstevel@tonic-gate 101*0Sstevel@tonic-gate static HostStatus 102*0Sstevel@tonic-gate check_host_in_hostfile_by_key_or_type(const char *filename, 103*0Sstevel@tonic-gate const char *host, Key *key, int keytype, Key *found, int *numret) 104*0Sstevel@tonic-gate { 105*0Sstevel@tonic-gate FILE *f; 106*0Sstevel@tonic-gate char line[8192]; 107*0Sstevel@tonic-gate int linenum = 0; 108*0Sstevel@tonic-gate u_int kbits; 109*0Sstevel@tonic-gate char *cp, *cp2; 110*0Sstevel@tonic-gate HostStatus end_return; 111*0Sstevel@tonic-gate 112*0Sstevel@tonic-gate debug3("check_host_in_hostfile: filename %s", filename); 113*0Sstevel@tonic-gate 114*0Sstevel@tonic-gate /* Open the file containing the list of known hosts. */ 115*0Sstevel@tonic-gate f = fopen(filename, "r"); 116*0Sstevel@tonic-gate if (!f) 117*0Sstevel@tonic-gate return HOST_NEW; 118*0Sstevel@tonic-gate 119*0Sstevel@tonic-gate /* 120*0Sstevel@tonic-gate * Return value when the loop terminates. This is set to 121*0Sstevel@tonic-gate * HOST_CHANGED if we have seen a different key for the host and have 122*0Sstevel@tonic-gate * not found the proper one. 123*0Sstevel@tonic-gate */ 124*0Sstevel@tonic-gate end_return = HOST_NEW; 125*0Sstevel@tonic-gate 126*0Sstevel@tonic-gate /* Go through the file. */ 127*0Sstevel@tonic-gate while (fgets(line, sizeof(line), f)) { 128*0Sstevel@tonic-gate cp = line; 129*0Sstevel@tonic-gate linenum++; 130*0Sstevel@tonic-gate 131*0Sstevel@tonic-gate /* Skip any leading whitespace, comments and empty lines. */ 132*0Sstevel@tonic-gate for (; *cp == ' ' || *cp == '\t'; cp++) 133*0Sstevel@tonic-gate ; 134*0Sstevel@tonic-gate if (!*cp || *cp == '#' || *cp == '\n') 135*0Sstevel@tonic-gate continue; 136*0Sstevel@tonic-gate 137*0Sstevel@tonic-gate /* Find the end of the host name portion. */ 138*0Sstevel@tonic-gate for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 139*0Sstevel@tonic-gate ; 140*0Sstevel@tonic-gate 141*0Sstevel@tonic-gate /* Check if the host name matches. */ 142*0Sstevel@tonic-gate if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) 143*0Sstevel@tonic-gate continue; 144*0Sstevel@tonic-gate 145*0Sstevel@tonic-gate /* Got a match. Skip host name. */ 146*0Sstevel@tonic-gate cp = cp2; 147*0Sstevel@tonic-gate 148*0Sstevel@tonic-gate /* 149*0Sstevel@tonic-gate * Extract the key from the line. This will skip any leading 150*0Sstevel@tonic-gate * whitespace. Ignore badly formatted lines. 151*0Sstevel@tonic-gate */ 152*0Sstevel@tonic-gate if (!hostfile_read_key(&cp, &kbits, found)) 153*0Sstevel@tonic-gate continue; 154*0Sstevel@tonic-gate 155*0Sstevel@tonic-gate if (numret != NULL) 156*0Sstevel@tonic-gate *numret = linenum; 157*0Sstevel@tonic-gate 158*0Sstevel@tonic-gate if (key == NULL) { 159*0Sstevel@tonic-gate /* we found a key of the requested type */ 160*0Sstevel@tonic-gate if (found->type == keytype) 161*0Sstevel@tonic-gate return HOST_FOUND; 162*0Sstevel@tonic-gate continue; 163*0Sstevel@tonic-gate } 164*0Sstevel@tonic-gate 165*0Sstevel@tonic-gate if (!hostfile_check_key(kbits, found, host, filename, linenum)) 166*0Sstevel@tonic-gate continue; 167*0Sstevel@tonic-gate 168*0Sstevel@tonic-gate /* Check if the current key is the same as the given key. */ 169*0Sstevel@tonic-gate if (key_equal(key, found)) { 170*0Sstevel@tonic-gate /* Ok, they match. */ 171*0Sstevel@tonic-gate debug3("check_host_in_hostfile: match line %d", linenum); 172*0Sstevel@tonic-gate fclose(f); 173*0Sstevel@tonic-gate return HOST_OK; 174*0Sstevel@tonic-gate } 175*0Sstevel@tonic-gate /* 176*0Sstevel@tonic-gate * They do not match. We will continue to go through the 177*0Sstevel@tonic-gate * file; however, we note that we will not return that it is 178*0Sstevel@tonic-gate * new. 179*0Sstevel@tonic-gate */ 180*0Sstevel@tonic-gate end_return = HOST_CHANGED; 181*0Sstevel@tonic-gate } 182*0Sstevel@tonic-gate /* Clear variables and close the file. */ 183*0Sstevel@tonic-gate fclose(f); 184*0Sstevel@tonic-gate 185*0Sstevel@tonic-gate /* 186*0Sstevel@tonic-gate * Return either HOST_NEW or HOST_CHANGED, depending on whether we 187*0Sstevel@tonic-gate * saw a different key for the host. 188*0Sstevel@tonic-gate */ 189*0Sstevel@tonic-gate return end_return; 190*0Sstevel@tonic-gate } 191*0Sstevel@tonic-gate 192*0Sstevel@tonic-gate HostStatus 193*0Sstevel@tonic-gate check_host_in_hostfile(const char *filename, const char *host, Key *key, 194*0Sstevel@tonic-gate Key *found, int *numret) 195*0Sstevel@tonic-gate { 196*0Sstevel@tonic-gate if (key == NULL) 197*0Sstevel@tonic-gate fatal("no key to look up"); 198*0Sstevel@tonic-gate return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0, 199*0Sstevel@tonic-gate found, numret)); 200*0Sstevel@tonic-gate } 201*0Sstevel@tonic-gate 202*0Sstevel@tonic-gate int 203*0Sstevel@tonic-gate lookup_key_in_hostfile_by_type(const char *filename, const char *host, 204*0Sstevel@tonic-gate int keytype, Key *found, int *numret) 205*0Sstevel@tonic-gate { 206*0Sstevel@tonic-gate return (check_host_in_hostfile_by_key_or_type(filename, host, NULL, 207*0Sstevel@tonic-gate keytype, found, numret) == HOST_FOUND); 208*0Sstevel@tonic-gate } 209*0Sstevel@tonic-gate 210*0Sstevel@tonic-gate /* 211*0Sstevel@tonic-gate * Appends an entry to the host file. Returns false if the entry could not 212*0Sstevel@tonic-gate * be appended. 213*0Sstevel@tonic-gate */ 214*0Sstevel@tonic-gate 215*0Sstevel@tonic-gate int 216*0Sstevel@tonic-gate add_host_to_hostfile(const char *filename, const char *host, Key *key) 217*0Sstevel@tonic-gate { 218*0Sstevel@tonic-gate FILE *f; 219*0Sstevel@tonic-gate int success = 0; 220*0Sstevel@tonic-gate if (key == NULL) 221*0Sstevel@tonic-gate return 1; /* XXX ? */ 222*0Sstevel@tonic-gate f = fopen(filename, "a"); 223*0Sstevel@tonic-gate if (!f) 224*0Sstevel@tonic-gate return 0; 225*0Sstevel@tonic-gate fprintf(f, "%s ", host); 226*0Sstevel@tonic-gate if (key_write(key, f)) { 227*0Sstevel@tonic-gate success = 1; 228*0Sstevel@tonic-gate } else { 229*0Sstevel@tonic-gate error("add_host_to_hostfile: saving key in %s failed", filename); 230*0Sstevel@tonic-gate } 231*0Sstevel@tonic-gate fprintf(f, "\n"); 232*0Sstevel@tonic-gate fclose(f); 233*0Sstevel@tonic-gate return success; 234*0Sstevel@tonic-gate } 235