X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5bae4ab8a3d797f4056d957da982ae91e77cfbec..1e3b8b0749ec6793df5d8a9aca41ad4cae79bd4a:/hostfile.c diff --git a/hostfile.c b/hostfile.c index 2bf077e9..1c3fb22a 100644 --- a/hostfile.c +++ b/hostfile.c @@ -1,287 +1,218 @@ /* - -hostfile.c - -Author: Tatu Ylonen - -Copyright (c) 1995 Tatu Ylonen , Espoo, Finland - All rights reserved - -Created: Thu Jun 29 07:10:56 1995 ylo - -Functions for manipulating the known hosts files. - -*/ + * Author: Tatu Ylonen + * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland + * All rights reserved + * Functions for manipulating the known hosts files. + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * + * Copyright (c) 1999,2000 Markus Friedl. All rights reserved. + * Copyright (c) 1999 Niels Provos. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ #include "includes.h" -RCSID("$Id$"); +RCSID("$OpenBSD: hostfile.c,v 1.23 2000/12/21 15:10:16 markus Exp $"); #include "packet.h" +#include "match.h" #include "ssh.h" +#include +#include +#include "key.h" +#include "hostfile.h" -/* Reads a multiple-precision integer in hex from the buffer, and advances the - pointer. The integer must already be initialized. This function is - permitted to modify the buffer. This leaves *cpp to point just beyond - the last processed (and maybe modified) character. Note that this may - modify the buffer containing the number. */ +/* + * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the + * pointer over the key. Skips any whitespace at the beginning and at end. + */ int -auth_rsa_read_bignum(char **cpp, BIGNUM *value) +hostfile_read_key(char **cpp, u_int *bitsp, Key *ret) { - char *cp = *cpp; - int len, old; - - /* Skip any leading whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++) - ; - - /* Check that it begins with a hex digit. */ - if (*cp < '0' || *cp > '9') - return 0; - - /* Save starting position. */ - *cpp = cp; + char *cp; - /* Move forward until all hex digits skipped. */ - for (; *cp >= '0' && *cp <= '9'; cp++) - ; + /* Skip leading whitespace. */ + for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) + ; - /* Compute the length of the hex number. */ - len = cp - *cpp; + if (key_read(ret, &cp) != 1) + return 0; - /* Save the old terminating character, and replace it by \0. */ - old = *cp; - *cp = 0; + /* Skip trailing whitespace. */ + for (; *cp == ' ' || *cp == '\t'; cp++) + ; - - /* Parse the number. */ - if (BN_dec2bn(&value, *cpp) == 0) - return 0; - - /* Restore old terminating character. */ - *cp = old; - - /* Move beyond the number and return success. */ - *cpp = cp; - return 1; + /* Return results. */ + *cpp = cp; + *bitsp = key_size(ret); + return 1; } -/* Parses an RSA key (number of bits, e, n) from a string. Moves the pointer - over the key. Skips any whitespace at the beginning and at end. */ - int -auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM *e, BIGNUM *n) +auth_rsa_read_key(char **cpp, u_int *bitsp, BIGNUM * e, BIGNUM * n) { - unsigned int bits; - char *cp; - - /* Skip leading whitespace. */ - for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) - ; - - /* Get number of bits. */ - if (*cp < '0' || *cp > '9') - return 0; /* Bad bit count... */ - for (bits = 0; *cp >= '0' && *cp <= '9'; cp++) - bits = 10 * bits + *cp - '0'; - - /* Get public exponent. */ - if (!auth_rsa_read_bignum(&cp, e)) - return 0; - - /* Get public modulus. */ - if (!auth_rsa_read_bignum(&cp, n)) - return 0; - - /* Skip trailing whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++) - ; - - /* Return results. */ - *cpp = cp; - *bitsp = bits; - return 1; + Key *k = key_new(KEY_RSA1); + int ret = hostfile_read_key(cpp, bitsp, k); + BN_copy(e, k->rsa->e); + BN_copy(n, k->rsa->n); + key_free(k); + return ret; } -/* Tries to match the host name (which must be in all lowercase) against the - comma-separated sequence of subpatterns (each possibly preceded by ! to - indicate negation). Returns true if there is a positive match; zero - otherwise. */ - int -match_hostname(const char *host, const char *pattern, unsigned int len) +hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) { - char sub[1024]; - int negated; - int got_positive; - unsigned int i, subi; - - got_positive = 0; - for (i = 0; i < len;) - { - /* Check if the subpattern is negated. */ - if (pattern[i] == '!') - { - negated = 1; - i++; + if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL) + return 1; + if (bits != BN_num_bits(key->rsa->n)) { + log("Warning: %s, line %d: keysize mismatch for host %s: " + "actual %d vs. announced %d.", + filename, linenum, host, BN_num_bits(key->rsa->n), bits); + log("Warning: replace %d with %d in %s, line %d.", + bits, BN_num_bits(key->rsa->n), filename, linenum); } - else - negated = 0; - - /* Extract the subpattern up to a comma or end. Convert the subpattern - to lowercase. */ - for (subi = 0; - i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; - subi++, i++) - sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i]; - /* If subpattern too long, return failure (no match). */ - if (subi >= sizeof(sub) - 1) - return 0; - - /* If the subpattern was terminated by a comma, skip the comma. */ - if (i < len && pattern[i] == ',') - i++; - - /* Null-terminate the subpattern. */ - sub[subi] = '\0'; - - /* Try to match the subpattern against the host name. */ - if (match_pattern(host, sub)) { - if (negated) - return 0; /* Fail if host matches any negated subpattern. */ - else - got_positive = 1; - } - } - - /* Return success if got a positive match. If there was a negative match, - we have already returned zero and never get here. */ - return got_positive; + return 1; } -/* Checks whether the given host (which must be in all lowercase) is - already in the list of our known hosts. - Returns HOST_OK if the host is known and has the specified key, - HOST_NEW if the host is not known, and HOST_CHANGED if the host is known - but used to have a different host key. */ +/* + * Checks whether the given host (which must be in all lowercase) is already + * in the list of our known hosts. Returns HOST_OK if the host is known and + * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED + * if the host is known but used to have a different host key. + */ HostStatus -check_host_in_hostfile(const char *filename, - const char *host, unsigned int bits, - BIGNUM *e, BIGNUM *n, - BIGNUM *ke, BIGNUM *kn) +check_host_in_hostfile(const char *filename, const char *host, Key *key, + Key *found, int *numret) { - FILE *f; - char line[8192]; - unsigned int kbits, hostlen; - char *cp, *cp2; - HostStatus end_return; - struct stat st; - - /* Open the file containing the list of known hosts. */ - f = fopen(filename, "r"); - if (!f) - { - if (stat(filename, &st) >= 0) - { - packet_send_debug("Could not open %.900s for reading.", filename); - packet_send_debug("If your home directory is on an NFS volume, it may need to be world-readable."); - } - return HOST_NEW; - } - - /* Cache the length of the host name. */ - hostlen = strlen(host); - - /* Return value when the loop terminates. This is set to HOST_CHANGED if - we have seen a different key for the host and have not found the proper - one. */ - end_return = HOST_NEW; - - /* Go trough the file. */ - while (fgets(line, sizeof(line), f)) - { - cp = line; - - /* Skip any leading whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++) - ; - - /* Ignore comment lines and empty lines. */ - if (!*cp || *cp == '#' || *cp == '\n') - continue; - - /* Find the end of the host name portion. */ - for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) - ; - - /* Check if the host name matches. */ - if (!match_hostname(host, cp, (unsigned int)(cp2 - cp))) - continue; - - /* Got a match. Skip host name. */ - cp = cp2; - - /* Extract the key from the line. This will skip any leading - whitespace. Ignore badly formatted lines. */ - if (!auth_rsa_read_key(&cp, &kbits, ke, kn)) - continue; - - /* Check if the current key is the same as the previous one. */ - if (kbits == bits && BN_cmp(ke, e) == 0 && BN_cmp(kn, n) == 0) - { - /* Ok, they match. */ - fclose(f); - return HOST_OK; + FILE *f; + char line[8192]; + int linenum = 0; + u_int kbits, hostlen; + char *cp, *cp2; + HostStatus end_return; + + if (key == NULL) + fatal("no key to look up"); + /* Open the file containing the list of known hosts. */ + f = fopen(filename, "r"); + if (!f) + return HOST_NEW; + + /* Cache the length of the host name. */ + hostlen = strlen(host); + + /* + * Return value when the loop terminates. This is set to + * HOST_CHANGED if we have seen a different key for the host and have + * not found the proper one. + */ + end_return = HOST_NEW; + + /* Go trough the file. */ + while (fgets(line, sizeof(line), f)) { + cp = line; + linenum++; + + /* Skip any leading whitespace, comments and empty lines. */ + for (; *cp == ' ' || *cp == '\t'; cp++) + ; + if (!*cp || *cp == '#' || *cp == '\n') + continue; + + /* Find the end of the host name portion. */ + for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) + ; + + /* Check if the host name matches. */ + if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) + continue; + + /* Got a match. Skip host name. */ + cp = cp2; + + /* + * Extract the key from the line. This will skip any leading + * whitespace. Ignore badly formatted lines. + */ + if (!hostfile_read_key(&cp, &kbits, found)) + continue; + if (!hostfile_check_key(kbits, found, host, filename, linenum)) + continue; + + if (numret != NULL) + *numret = linenum; + + /* Check if the current key is the same as the given key. */ + if (key_equal(key, found)) { + /* Ok, they match. */ + fclose(f); + return HOST_OK; + } + /* + * They do not match. We will continue to go through the + * file; however, we note that we will not return that it is + * new. + */ + end_return = HOST_CHANGED; } - - /* They do not match. We will continue to go through the file; however, - we note that we will not return that it is new. */ - end_return = HOST_CHANGED; - } - /* Clear variables and close the file. */ - fclose(f); - - /* Return either HOST_NEW or HOST_CHANGED, depending on whether we saw a - different key for the host. */ - return end_return; + /* Clear variables and close the file. */ + fclose(f); + + /* + * Return either HOST_NEW or HOST_CHANGED, depending on whether we + * saw a different key for the host. + */ + return end_return; } -/* Appends an entry to the host file. Returns false if the entry - could not be appended. */ +/* + * Appends an entry to the host file. Returns false if the entry could not + * be appended. + */ int -add_host_to_hostfile(const char *filename, const char *host, - unsigned int bits, BIGNUM *e, BIGNUM *n) +add_host_to_hostfile(const char *filename, const char *host, Key *key) { - FILE *f; - char *buf; - - /* Open the file for appending. */ - f = fopen(filename, "a"); - if (!f) - return 0; - - /* Print the host name and key to the file. */ - fprintf(f, "%s %u ", host, bits); - buf = BN_bn2dec(e); - if (buf == NULL) { - error("add_host_to_hostfile: BN_bn2dec #1 failed"); - fclose(f); - return 0; - } - fprintf(f, "%s ", buf); - free (buf); - buf = BN_bn2dec(n); - if (buf == NULL) { - error("add_host_to_hostfile: BN_bn2dec #2 failed"); - fclose(f); - return 0; - } - fprintf(f, "%s\n", buf); - free (buf); - - /* Close the file. */ - fclose(f); - return 1; + FILE *f; + int success = 0; + if (key == NULL) + return 1; /* XXX ? */ + f = fopen(filename, "a"); + if (!f) + return 0; + fprintf(f, "%s ", host); + if (key_write(key, f)) { + success = 1; + } else { + error("add_host_to_hostfile: saving key in %s failed", filename); + } + fprintf(f, "\n"); + fclose(f); + return success; }