Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 2 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 3 | * hostfile.c |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 4 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 6 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 8 | * All rights reserved |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 9 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 10 | * Created: Thu Jun 29 07:10:56 1995 ylo |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 11 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 12 | * Functions for manipulating the known hosts files. |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 13 | * |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 14 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 15 | |
| 16 | #include "includes.h" |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 17 | RCSID("$OpenBSD: hostfile.c,v 1.16 2000/04/14 10:30:31 markus Exp $"); |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 18 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 19 | #include "packet.h" |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 20 | #include "match.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 21 | #include "ssh.h" |
Damien Miller | 5f05637 | 2000-04-16 12:31:48 +1000 | [diff] [blame] | 22 | #include <openssl/rsa.h> |
| 23 | #include <openssl/dsa.h> |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 24 | #include "key.h" |
| 25 | #include "hostfile.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 26 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 27 | /* |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 28 | * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the |
| 29 | * pointer over the key. Skips any whitespace at the beginning and at end. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 30 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 31 | |
| 32 | int |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 33 | hostfile_read_key(char **cpp, unsigned int *bitsp, Key *ret) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 34 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 35 | unsigned int bits; |
| 36 | char *cp; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 37 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 38 | /* Skip leading whitespace. */ |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 39 | for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) |
| 40 | ; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 41 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 42 | /* Get number of bits. */ |
| 43 | if (*cp < '0' || *cp > '9') |
| 44 | return 0; /* Bad bit count... */ |
| 45 | for (bits = 0; *cp >= '0' && *cp <= '9'; cp++) |
| 46 | bits = 10 * bits + *cp - '0'; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 47 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 48 | if (!key_read(ret, bits, &cp)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 49 | return 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 50 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 51 | /* Skip trailing whitespace. */ |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 52 | for (; *cp == ' ' || *cp == '\t'; cp++) |
| 53 | ; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 54 | |
| 55 | /* Return results. */ |
| 56 | *cpp = cp; |
| 57 | *bitsp = bits; |
| 58 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 59 | } |
| 60 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 61 | int |
| 62 | auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n) |
| 63 | { |
| 64 | Key *k = key_new(KEY_RSA); |
| 65 | int ret = hostfile_read_key(cpp, bitsp, k); |
| 66 | BN_copy(e, k->rsa->e); |
| 67 | BN_copy(n, k->rsa->n); |
| 68 | key_free(k); |
| 69 | return ret; |
| 70 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 71 | |
| 72 | int |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 73 | hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 74 | { |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 75 | if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) |
| 76 | return 1; |
| 77 | if (bits != BN_num_bits(key->rsa->n)) { |
| 78 | error("Warning: %s, line %d: keysize mismatch for host %s: " |
| 79 | "actual %d vs. announced %d.", |
| 80 | filename, linenum, host, BN_num_bits(key->rsa->n), bits); |
| 81 | error("Warning: replace %d with %d in %s, line %d.", |
| 82 | bits, BN_num_bits(key->rsa->n), filename, linenum); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 83 | } |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 84 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 85 | } |
| 86 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 87 | /* |
| 88 | * Checks whether the given host (which must be in all lowercase) is already |
| 89 | * in the list of our known hosts. Returns HOST_OK if the host is known and |
| 90 | * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED |
| 91 | * if the host is known but used to have a different host key. |
| 92 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 93 | |
| 94 | HostStatus |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 95 | check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 96 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 97 | FILE *f; |
| 98 | char line[8192]; |
| 99 | int linenum = 0; |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 100 | unsigned int kbits, hostlen; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 101 | char *cp, *cp2; |
| 102 | HostStatus end_return; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 103 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 104 | if (key == NULL) |
| 105 | fatal("no key to look up"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 106 | /* Open the file containing the list of known hosts. */ |
| 107 | f = fopen(filename, "r"); |
| 108 | if (!f) |
| 109 | return HOST_NEW; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 110 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 111 | /* Cache the length of the host name. */ |
| 112 | hostlen = strlen(host); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 113 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 114 | /* |
| 115 | * Return value when the loop terminates. This is set to |
| 116 | * HOST_CHANGED if we have seen a different key for the host and have |
| 117 | * not found the proper one. |
| 118 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 119 | end_return = HOST_NEW; |
Damien Miller | 7e8e820 | 1999-11-16 13:37:16 +1100 | [diff] [blame] | 120 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 121 | /* Go trough the file. */ |
| 122 | while (fgets(line, sizeof(line), f)) { |
| 123 | cp = line; |
| 124 | linenum++; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 125 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 126 | /* Skip any leading whitespace, comments and empty lines. */ |
| 127 | for (; *cp == ' ' || *cp == '\t'; cp++) |
| 128 | ; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 129 | if (!*cp || *cp == '#' || *cp == '\n') |
| 130 | continue; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 131 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 132 | /* Find the end of the host name portion. */ |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 133 | for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) |
| 134 | ; |
Damien Miller | 7e8e820 | 1999-11-16 13:37:16 +1100 | [diff] [blame] | 135 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 136 | /* Check if the host name matches. */ |
| 137 | if (!match_hostname(host, cp, (unsigned int) (cp2 - cp))) |
| 138 | continue; |
| 139 | |
| 140 | /* Got a match. Skip host name. */ |
| 141 | cp = cp2; |
| 142 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 143 | /* |
| 144 | * Extract the key from the line. This will skip any leading |
| 145 | * whitespace. Ignore badly formatted lines. |
| 146 | */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 147 | if (!hostfile_read_key(&cp, &kbits, found)) |
| 148 | continue; |
| 149 | if (!hostfile_check_key(kbits, found, host, filename, linenum)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 150 | continue; |
| 151 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 152 | /* Check if the current key is the same as the given key. */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 153 | if (key_equal(key, found)) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 154 | /* Ok, they match. */ |
| 155 | fclose(f); |
| 156 | return HOST_OK; |
| 157 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 158 | /* |
| 159 | * They do not match. We will continue to go through the |
| 160 | * file; however, we note that we will not return that it is |
| 161 | * new. |
| 162 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 163 | end_return = HOST_CHANGED; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 164 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 165 | /* Clear variables and close the file. */ |
| 166 | fclose(f); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 167 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 168 | /* |
| 169 | * Return either HOST_NEW or HOST_CHANGED, depending on whether we |
| 170 | * saw a different key for the host. |
| 171 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 172 | return end_return; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 173 | } |
| 174 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 175 | /* |
| 176 | * Appends an entry to the host file. Returns false if the entry could not |
| 177 | * be appended. |
| 178 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 179 | |
| 180 | int |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 181 | add_host_to_hostfile(const char *filename, const char *host, Key *key) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 182 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 183 | FILE *f; |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 184 | int success = 0; |
| 185 | |
| 186 | if (key == NULL) |
| 187 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 188 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 189 | /* Open the file for appending. */ |
| 190 | f = fopen(filename, "a"); |
| 191 | if (!f) |
| 192 | return 0; |
Damien Miller | 7e8e820 | 1999-11-16 13:37:16 +1100 | [diff] [blame] | 193 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 194 | fprintf(f, "%s ", host); |
| 195 | if (key_write(key, f)) { |
| 196 | fprintf(f, "\n"); |
| 197 | success = 1; |
| 198 | } else { |
| 199 | error("add_host_to_hostfile: saving key failed"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 200 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 201 | |
| 202 | /* Close the file. */ |
| 203 | fclose(f); |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 204 | return success; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 205 | } |