diff options
Diffstat (limited to 'crypto/openssh/hostfile.c')
| -rw-r--r-- | crypto/openssh/hostfile.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/crypto/openssh/hostfile.c b/crypto/openssh/hostfile.c new file mode 100644 index 0000000..ef97825 --- /dev/null +++ b/crypto/openssh/hostfile.c @@ -0,0 +1,217 @@ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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("$OpenBSD: hostfile.c,v 1.20 2000/09/07 20:27:51 deraadt Exp $"); +RCSID("$FreeBSD$"); + +#include "packet.h" +#include "match.h" +#include "ssh.h" +#include <openssl/rsa.h> +#include <openssl/dsa.h> +#include "key.h" +#include "hostfile.h" + +/* + * 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 +hostfile_read_key(char **cpp, unsigned int *bitsp, Key *ret) +{ + unsigned int bits; + char *cp; + + /* Skip leading whitespace. */ + for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) + ; + + bits = key_read(ret, &cp); + if (bits == 0) + return 0; + + /* Skip trailing whitespace. */ + for (; *cp == ' ' || *cp == '\t'; cp++) + ; + + /* Return results. */ + *cpp = cp; + *bitsp = bits; + return 1; +} + +int +auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n) +{ + Key *k = key_new(KEY_RSA); + 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; +} + +int +hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum) +{ + if (key == NULL || key->type != KEY_RSA || 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 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. + */ + +HostStatus +check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found) +{ + FILE *f; + char line[8192]; + int linenum = 0; + unsigned 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, (unsigned 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; + + /* 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; + } + /* 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. + */ + +int +add_host_to_hostfile(const char *filename, const char *host, Key *key) +{ + 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; +} |
