/*
* Match keys against a specified key, or look one up by key type.
*
* If looking for a keytype (key == NULL) and one is found then return
* HOST_FOUND, otherwise HOST_NEW.
*
* If looking for a key (key != NULL):
* 1. If the key is a cert and a matching CA is found, return HOST_OK
* 2. If the key is not a cert and a matching key is found, return HOST_OK
* 3. If no key matches but a key with a different type is found, then
* return HOST_CHANGED
* 4. If no matching keys are found, then return HOST_NEW.
*
* Finally, check any found key is not revoked.
*/
static HostStatus
check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
Key *k, int keytype, const struct hostkey_entry **found)
{
u_int i;
HostStatus end_return = HOST_NEW;
int want_cert = key_is_cert(k);
HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2;
if (found != NULL)
*found = NULL;
for (i = 0; i < hostkeys->num_entries; i++) {
if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1)
continue;
if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1)
continue;
if (hostkeys->entries[i].marker != want_marker)
continue;
if (k == NULL) {
if (hostkeys->entries[i].key->type != keytype)
continue;
end_return = HOST_FOUND;
if (found != NULL)
*found = hostkeys->entries + i;
k = hostkeys->entries[i].key;
break;
}
if (want_cert) {
if (key_equal_public(k->cert->signature_key,
hostkeys->entries[i].key)) {
/* A matching CA exists */
end_return = HOST_OK;
if (found != NULL)
*found = hostkeys->entries + i;
break;
}
} else {
if (key_equal(k, hostkeys->entries[i].key)) {
end_return = HOST_OK;
if (found != NULL)
*found = hostkeys->entries + i;
break;
}
/* A non-maching key exists */
end_return = HOST_CHANGED;
if (found != NULL)
*found = hostkeys->entries + i;
}
}
if (check_key_not_revoked(hostkeys, k) != 0) {
end_return = HOST_REVOKED;
if (found != NULL)
*found = NULL;
}
return end_return;
}
static int
check_key_not_revoked(struct hostkeys *hostkeys, Key *k)
{
int is_cert = key_is_cert(k);
u_int i;
for (i = 0; i < hostkeys->num_entries; i++) {
if (hostkeys->entries[i].marker != MRK_REVOKE)
continue;
if (key_equal_public(k, hostkeys->entries[i].key))
return -1;
if (is_cert &&
key_equal_public(k->cert->signature_key,
hostkeys->entries[i].key))
return -1;
}
return 0;
}
int
main(int argc, char **argv)
{
Buffer b;
Options options;
#define NUM_KEYTYPES 3
Key *keys[NUM_KEYTYPES], *key = NULL;
struct passwd *pw;
int key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
u_char *signature, *data;
char *host;
u_int slen, dlen;
u_int32_t rnd[256];
/* Ensure that stdin and stdout are connected */
if ((fd = open(_PATH_DEVNULL, O_RDWR)) < 2)
exit(1);
/* Leave /dev/null fd iff it is attached to stderr */
if (fd > 2)
close(fd);
i = 0;
key_fd[i++] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_ECDSA_KEY_FILE, O_RDONLY);
key_fd[i++] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
original_real_uid = getuid(); /* XXX readconf.c needs this */
if ((pw = getpwuid(original_real_uid)) == NULL)
fatal("getpwuid failed");
pw = pwcopy(pw);
permanently_set_uid(pw);
#ifdef DEBUG_SSH_KEYSIGN
log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif
/* verify that ssh-keysign is enabled by the admin */
initialize_options(&options);
(void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options, 0);
fill_default_options(&options);
if (options.enable_ssh_keysign != 1)
fatal("ssh-keysign not enabled in %s",
_PATH_HOST_CONFIG_FILE);
for (i = found = 0; i < NUM_KEYTYPES; i++) {
if (key_fd[i] != -1)
found = 1;
}
if (found == 0)
fatal("could not open any host key");
OpenSSL_add_all_algorithms();
for (i = 0; i < 256; i++)
rnd[i] = arc4random();
RAND_seed(rnd, sizeof(rnd));
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
keys[i] = NULL;
if (key_fd[i] == -1)
continue;
keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
NULL, NULL);
close(key_fd[i]);
if (keys[i] != NULL)
found = 1;
}
if (!found)
fatal("no hostkey found");
buffer_init(&b);
if (ssh_msg_recv(STDIN_FILENO, &b) < 0)
fatal("ssh_msg_recv failed");
if (buffer_get_char(&b) != version)
fatal("bad version");
fd = buffer_get_int(&b);
if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
fatal("bad fd");
if ((host = get_local_name(fd)) == NULL)
fatal("cannot get local name for fd");
data = buffer_get_string(&b, &dlen);
if (valid_request(pw, host, &key, data, dlen) < 0)
fatal("not a valid request");
xfree(host);
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
if (keys[i] != NULL &&
key_equal_public(key, keys[i])) {
found = 1;
break;
}
}
if (!found)
fatal("no matching hostkey found");
if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
fatal("key_sign failed");
xfree(data);
/* send reply */
buffer_clear(&b);
buffer_put_string(&b, signature, slen);
if (ssh_msg_send(STDOUT_FILENO, version, &b) == -1)
fatal("ssh_msg_send failed");
return (0);
}
