+/* $OpenBSD: hostfile.c,v 1.46 2009/10/11 23:03:15 djm Exp $ */
/*
+ * 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.
+ */
-hostfile.c
+#include "includes.h"
-Author: Tatu Ylonen <ylo@cs.hut.fi>
+#include <sys/types.h>
-Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- All rights reserved
+#include <netinet/in.h>
-Created: Thu Jun 29 07:10:56 1995 ylo
+#include <openssl/hmac.h>
+#include <openssl/sha.h>
-Functions for manipulating the known hosts files.
+#include <resolv.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
-*/
+#include "xmalloc.h"
+#include "match.h"
+#include "key.h"
+#include "hostfile.h"
+#include "log.h"
-#include "includes.h"
-RCSID("$Id$");
+static int
+extract_salt(const char *s, u_int l, char *salt, size_t salt_len)
+{
+ char *p, *b64salt;
+ u_int b64len;
+ int ret;
-#include "packet.h"
-#include "ssh.h"
+ if (l < sizeof(HASH_MAGIC) - 1) {
+ debug2("extract_salt: string too short");
+ return (-1);
+ }
+ if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
+ debug2("extract_salt: invalid magic identifier");
+ return (-1);
+ }
+ s += sizeof(HASH_MAGIC) - 1;
+ l -= sizeof(HASH_MAGIC) - 1;
+ if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
+ debug2("extract_salt: missing salt termination character");
+ return (-1);
+ }
-/* 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. */
+ b64len = p - s;
+ /* Sanity check */
+ if (b64len == 0 || b64len > 1024) {
+ debug2("extract_salt: bad encoded salt length %u", b64len);
+ return (-1);
+ }
+ b64salt = xmalloc(1 + b64len);
+ memcpy(b64salt, s, b64len);
+ b64salt[b64len] = '\0';
+
+ ret = __b64_pton(b64salt, salt, salt_len);
+ xfree(b64salt);
+ if (ret == -1) {
+ debug2("extract_salt: salt decode error");
+ return (-1);
+ }
+ if (ret != SHA_DIGEST_LENGTH) {
+ debug2("extract_salt: expected salt len %d, got %d",
+ SHA_DIGEST_LENGTH, ret);
+ return (-1);
+ }
-int
-auth_rsa_read_bignum(char **cpp, BIGNUM *value)
+ return (0);
+}
+
+char *
+host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
{
- char *cp = *cpp;
- int len, old;
+ const EVP_MD *md = EVP_sha1();
+ HMAC_CTX mac_ctx;
+ char salt[256], result[256], uu_salt[512], uu_result[512];
+ static char encoded[1024];
+ u_int i, len;
+
+ len = EVP_MD_size(md);
+
+ if (name_from_hostfile == NULL) {
+ /* Create new salt */
+ for (i = 0; i < len; i++)
+ salt[i] = arc4random();
+ } else {
+ /* Extract salt from known host entry */
+ if (extract_salt(name_from_hostfile, src_len, salt,
+ sizeof(salt)) == -1)
+ return (NULL);
+ }
- /* Skip any leading whitespace. */
- for (; *cp == ' ' || *cp == '\t'; cp++)
- ;
+ HMAC_Init(&mac_ctx, salt, len, md);
+ HMAC_Update(&mac_ctx, host, strlen(host));
+ HMAC_Final(&mac_ctx, result, NULL);
+ HMAC_cleanup(&mac_ctx);
- /* Check that it begins with a hex digit. */
- if (*cp < '0' || *cp > '9')
- return 0;
+ if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
+ __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
+ fatal("host_hash: __b64_ntop failed");
- /* Save starting position. */
- *cpp = cp;
+ snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
+ HASH_DELIM, uu_result);
- /* Move forward until all hex digits skipped. */
- for (; *cp >= '0' && *cp <= '9'; cp++)
- ;
+ return (encoded);
+}
+
+/*
+ * 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.
+ */
- /* Compute the length of the hex number. */
- len = cp - *cpp;
+int
+hostfile_read_key(char **cpp, u_int *bitsp, Key *ret)
+{
+ char *cp;
- /* Save the old terminating character, and replace it by \0. */
- old = *cp;
- *cp = 0;
+ /* Skip leading whitespace. */
+ for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
+ ;
-
- /* Parse the number. */
- if (BN_dec2bn(&value, *cpp) == 0)
- return 0;
+ if (key_read(ret, &cp) != 1)
+ return 0;
- /* Restore old terminating character. */
- *cp = old;
+ /* Skip trailing whitespace. */
+ for (; *cp == ' ' || *cp == '\t'; cp++)
+ ;
- /* 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)
+static int
+hostfile_check_key(int bits, const Key *key, const char *host, const char *filename, int linenum)
{
- 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;
+ if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL)
+ return 1;
+ if (bits != BN_num_bits(key->rsa->n)) {
+ logit("Warning: %s, line %d: keysize mismatch for host %s: "
+ "actual %d vs. announced %d.",
+ filename, linenum, host, BN_num_bits(key->rsa->n), bits);
+ logit("Warning: replace %d with %d in %s, line %d.",
+ bits, BN_num_bits(key->rsa->n), filename, linenum);
+ }
+ 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)
+/*
+ * 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.
+ *
+ * If no 'key' has been specified and a key of type 'keytype' is known
+ * for the specified host, then HOST_FOUND is returned.
+ */
+
+static HostStatus
+check_host_in_hostfile_by_key_or_type(const char *filename,
+ const char *host, const Key *key, int keytype, Key *found, int *numret)
{
- 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++;
+ FILE *f;
+ char line[8192];
+ int linenum = 0;
+ u_int kbits;
+ char *cp, *cp2, *hashed_host;
+ HostStatus end_return;
+
+ debug3("check_host_in_hostfile: host %s filename %s", host, filename);
+
+ /* Open the file containing the list of known hosts. */
+ f = fopen(filename, "r");
+ if (!f)
+ return HOST_NEW;
+
+ /*
+ * 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 through 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) {
+ if (*cp != HASH_DELIM)
+ continue;
+ hashed_host = host_hash(host, cp, (u_int) (cp2 - cp));
+ if (hashed_host == NULL) {
+ debug("Invalid hashed host line %d of %s",
+ linenum, filename);
+ continue;
+ }
+ if (strncmp(hashed_host, cp, (u_int) (cp2 - cp)) != 0)
+ 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 (numret != NULL)
+ *numret = linenum;
+
+ if (key == NULL) {
+ /* we found a key of the requested type */
+ if (found->type == keytype) {
+ fclose(f);
+ return HOST_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. */
+ 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.
+ */
+ end_return = HOST_CHANGED;
}
- 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;
+ /* 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;
}
-/* 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, const Key *key,
+ Key *found, int *numret)
{
- FILE *f;
- char line[8192];
- int linenum = 0;
- unsigned int bits, kbits, hostlen;
- char *cp, *cp2;
- HostStatus end_return;
-
- /* 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;
-
- /* size of modulus 'n' */
- bits = BN_num_bits(n);
-
- /* Go trough 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. */
- 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;
-
- 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);
- }
-
- /* Check if the current key is the same as the given key. */
- if (kbits == bits && BN_cmp(ke, e) == 0 && BN_cmp(kn, n) == 0)
- {
- /* 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;
+ if (key == NULL)
+ fatal("no key to look up");
+ return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0,
+ found, numret));
}
-/* Appends an entry to the host file. Returns false if the entry
- could not be appended. */
+int
+lookup_key_in_hostfile_by_type(const char *filename, const char *host,
+ int keytype, Key *found, int *numret)
+{
+ return (check_host_in_hostfile_by_key_or_type(filename, host, NULL,
+ keytype, found, numret) == HOST_FOUND);
+}
+
+/*
+ * 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, const Key *key,
+ int store_hash)
{
- FILE *f;
- char *buf;
- unsigned int bits;
-
- /* Open the file for appending. */
- 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\n", buf);
- free (buf);
-
- /* Close the file. */
- fclose(f);
- return 1;
+ FILE *f;
+ int success = 0;
+ char *hashed_host = NULL;
+
+ if (key == NULL)
+ return 1; /* XXX ? */
+ f = fopen(filename, "a");
+ if (!f)
+ return 0;
+
+ if (store_hash) {
+ if ((hashed_host = host_hash(host, NULL, 0)) == NULL) {
+ error("add_host_to_hostfile: host_hash failed");
+ fclose(f);
+ return 0;
+ }
+ }
+ fprintf(f, "%s ", store_hash ? hashed_host : 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;
}
andersk / openssh.git / blobdiff