X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5260325f3150ad441f310d31239beeb765f716ed..f564d016e40aed0eaa2b63c4292211d2ca01fe70:/hostfile.c diff --git a/hostfile.c b/hostfile.c index 6f2cc9d4..eeed920f 100644 --- a/hostfile.c +++ b/hostfile.c @@ -1,285 +1,215 @@ /* - * - * 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. - * + * + * 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 1.28 2001/06/25 08:25:37 markus Exp $"); #include "packet.h" -#include "ssh.h" +#include "match.h" +#include "key.h" +#include "hostfile.h" +#include "log.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. */ - -int -auth_rsa_read_bignum(char **cpp, BIGNUM * value) -{ - 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; - - /* Move forward until all hex digits skipped. */ - for (; *cp >= '0' && *cp <= '9'; cp++); - - /* Compute the length of the hex number. */ - len = cp - *cpp; - - /* Save the old terminating character, and replace it by \0. */ - old = *cp; - *cp = 0; - - - /* 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; -} - -/* 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. */ +/* + * 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_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n) +static int +hostfile_read_key(char **cpp, u_int *bitsp, Key *ret) { - 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'; + for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) + ; - /* Get public exponent. */ - if (!auth_rsa_read_bignum(&cp, e)) - return 0; - - /* Get public modulus. */ - if (!auth_rsa_read_bignum(&cp, n)) + if (key_read(ret, &cp) != 1) return 0; /* Skip trailing whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++); + for (; *cp == ' ' || *cp == '\t'; cp++) + ; /* Return results. */ *cpp = cp; - *bitsp = bits; + *bitsp = key_size(ret); return 1; } -/* 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) +auth_rsa_read_key(char **cpp, u_int *bitsp, BIGNUM * e, BIGNUM * n) { - 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++; - } 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'; + 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; +} - /* 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; - } +static int +hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) +{ + 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); } - - /* 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, - 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]; int linenum = 0; - unsigned int bits, kbits, hostlen; + u_int kbits; char *cp, *cp2; HostStatus end_return; + debug3("check_host_in_hostfile: filename %s", filename); + 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. */ + /* + * 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; - /* size of modulus 'n' */ - bits = BN_num_bits(n); - - /* Go trough the file. */ + /* Go through the file. */ while (fgets(line, sizeof(line), f)) { cp = line; linenum++; - /* Skip any leading whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++); - - /* Ignore comment lines and empty lines. */ + /* 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++); + for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) + ; /* Check if the host name matches. */ - if (!match_hostname(host, cp, (unsigned int) (cp2 - cp))) + 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 (!auth_rsa_read_key(&cp, &kbits, ke, kn)) + /* + * 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 (kbits != BN_num_bits(kn)) { - error("Warning: error in %s, line %d: keysize mismatch for host %s: " - "actual size %d vs. announced %d.", - filename, linenum, host, BN_num_bits(kn), kbits); - error("Warning: replace %d with %d in %s, line %d.", - kbits, BN_num_bits(kn), filename, linenum); - } + if (numret != NULL) + *numret = linenum; + /* Check if the current key is the same as the given key. */ - if (BN_cmp(ke, e) == 0 && BN_cmp(kn, n) == 0) { + if (key_equal(key, found)) { /* Ok, they match. */ + debug3("check_host_in_hostfile: match line %d", linenum); 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. */ + /* + * 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 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, - BIGNUM * e, BIGNUM * n) +add_host_to_hostfile(const char *filename, const char *host, Key *key) { FILE *f; - char *buf; - unsigned int bits; - - /* Open the file for appending. */ + int success = 0; + if (key == NULL) + return 1; /* XXX ? */ f = fopen(filename, "a"); if (!f) return 0; - - /* size of modulus 'n' */ - bits = BN_num_bits(n); - - /* 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(e) 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(n) failed"); - fclose(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, "%s\n", buf); - free(buf); - - /* Close the file. */ + fprintf(f, "\n"); fclose(f); - return 1; + return success; }