/* print all known host keys for a given host, but skip keys of given type */
static int
show_other_keys(struct hostkeys *hostkeys, struct sshkey *key)
{
int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
int i, ret = 0;
char *fp, *ra;
const struct hostkey_entry *found;
for (i = 0; type[i] != -1; i++) {
if (type[i] == key->type)
continue;
if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
continue;
fp = sshkey_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
ra = sshkey_fingerprint(found->key, SSH_FP_MD5,
SSH_FP_RANDOMART);
logit("WARNING: %s key found for host %s\n"
"in %s:%lu\n"
"%s key fingerprint %s.",
sshkey_type(found->key),
found->host, found->file, found->line,
sshkey_type(found->key), fp);
if (options.visual_host_key)
logit("%s", ra);
xfree(ra);
xfree(fp);
ret = 1;
}
return ret;
}
/*
* Formats any key left in authctxt->auth_method_key for inclusion in
* auth_log()'s message. Also includes authxtct->auth_method_info if present.
*/
static char *
format_method_key(Authctxt *authctxt)
{
const struct sshkey *key = authctxt->auth_method_key;
const char *methinfo = authctxt->auth_method_info;
char *fp, *ret = NULL;
if (key == NULL)
return NULL;
if (sshkey_is_cert(key)) {
fp = sshkey_fingerprint(key->cert->signature_key,
options.fingerprint_hash, SSH_FP_DEFAULT);
xasprintf(&ret, "%s ID %s (serial %llu) CA %s %s%s%s",
sshkey_type(key), key->cert->key_id,
(unsigned long long)key->cert->serial,
sshkey_type(key->cert->signature_key),
fp == NULL ? "(null)" : fp,
methinfo == NULL ? "" : ", ",
methinfo == NULL ? "" : methinfo);
free(fp);
} else {
fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT);
xasprintf(&ret, "%s %s%s%s", sshkey_type(key),
fp == NULL ? "(null)" : fp,
methinfo == NULL ? "" : ", ",
methinfo == NULL ? "" : methinfo);
free(fp);
}
return ret;
}
static int
host_delete(struct hostkey_foreach_line *l, void *_ctx)
{
struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
size_t i;
if (l->status == HKF_STATUS_MATCHED) {
if (l->marker != MRK_NONE) {
/* Don't remove CA and revocation lines */
fprintf(ctx->out, "%s\n", l->line);
return 0;
}
/* XXX might need a knob for this later */
/* Don't remove RSA1 keys */
if (l->key->type == KEY_RSA1) {
fprintf(ctx->out, "%s\n", l->line);
return 0;
}
/*
* If this line contains one of the keys that we will be
* adding later, then don't change it and mark the key for
* skipping.
*/
for (i = 0; i < ctx->nkeys; i++) {
if (sshkey_equal(ctx->keys[i], l->key)) {
ctx->skip_keys[i] = 1;
fprintf(ctx->out, "%s\n", l->line);
debug3("%s: %s key already at %s:%ld", __func__,
sshkey_type(l->key), l->path, l->linenum);
return 0;
}
}
/*
* Hostname matches and has no CA/revoke marker, delete it
* by *not* writing the line to ctx->out.
*/
do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
l->path, l->linenum, sshkey_type(l->key), ctx->host);
ctx->modified = 1;
return 0;
}
/* Retain non-matching hosts and invalid lines when deleting */
if (l->status == HKF_STATUS_INVALID) {
do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
l->path, l->linenum);
}
fprintf(ctx->out, "%s\n", l->line);
return 0;
}
/* returns 0 if key verifies or -1 if key does NOT verify */
int
verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key)
{
int flags = 0;
char *fp;
fp = sshkey_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
debug("Server host key: %s %s", sshkey_type(host_key), fp);
xfree(fp);
/* XXX certs are not yet supported for DNS */
if (!sshkey_is_cert(host_key) && options.verify_host_key_dns &&
verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
if (flags & DNS_VERIFY_FOUND) {
if (options.verify_host_key_dns == 1 &&
flags & DNS_VERIFY_MATCH &&
flags & DNS_VERIFY_SECURE)
return 0;
if (flags & DNS_VERIFY_MATCH) {
matching_host_key_dns = 1;
} else {
warn_changed_key(host_key);
error("Update the SSHFP RR in DNS with the new "
"host key to get rid of this message.");
}
}
}
return check_host_key(host, hostaddr, options.port, host_key, RDRW,
options.user_hostfiles, options.num_user_hostfiles,
options.system_hostfiles, options.num_system_hostfiles);
}
static int
record_hostkey(struct hostkey_foreach_line *l, void *_ctx)
{
struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx;
struct hostkeys *hostkeys = ctx->hostkeys;
struct hostkey_entry *tmp;
if (l->status == HKF_STATUS_INVALID) {
/* XXX make this verbose() in the future */
debug("%s:%ld: parse error in hostkeys file",
l->path, l->linenum);
return 0;
}
debug3("%s: found %skey type %s in file %s:%lu", __func__,
l->marker == MRK_NONE ? "" :
(l->marker == MRK_CA ? "ca " : "revoked "),
sshkey_type(l->key), l->path, l->linenum);
if ((tmp = reallocarray(hostkeys->entries,
hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
return SSH_ERR_ALLOC_FAIL;
hostkeys->entries = tmp;
hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
hostkeys->entries[hostkeys->num_entries].line = l->linenum;
hostkeys->entries[hostkeys->num_entries].key = l->key;
l->key = NULL; /* steal it */
hostkeys->entries[hostkeys->num_entries].marker = l->marker;
hostkeys->num_entries++;
ctx->num_loaded++;
return 0;
}
/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
int
auth_key_is_revoked(struct sshkey *key)
{
char *fp = NULL;
int r;
if (options.revoked_keys_file == NULL)
return 0;
if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
error("%s: fingerprint key: %s", __func__, ssh_err(r));
goto out;
}
r = sshkey_check_revoked(key, options.revoked_keys_file);
switch (r) {
case 0:
break; /* not revoked */
case SSH_ERR_KEY_REVOKED:
error("Authentication key %s %s revoked by file %s",
sshkey_type(key), fp, options.revoked_keys_file);
goto out;
default:
error("Error checking authentication key %s %s in "
"revoked keys file %s: %s", sshkey_type(key), fp,
options.revoked_keys_file, ssh_err(r));
goto out;
}
/* Success */
r = 0;
out:
free(fp);
return r == 0 ? 0 : 1;
}
static void
signature_tests(struct sshkey *k, struct sshkey *bad)
{
u_char i, buf[2049];
size_t lens[] = {
1, 2, 7, 8, 9, 15, 16, 17, 31, 32, 33, 127, 128, 129,
255, 256, 257, 1023, 1024, 1025, 2047, 2048, 2049
};
for (i = 0; i < (sizeof(lens)/sizeof(lens[0])); i++) {
test_subtest_info("%s key, banana length %zu",
sshkey_type(k), lens[i]);
banana(buf, lens[i]);
signature_test(k, bad, buf, lens[i]);
}
}
/*
* Performs the RSA authentication dialog with the client. This returns
* 0 if the client could not be authenticated, and 1 if authentication was
* successful. This may exit if there is a serious protocol violation.
*/
int
auth_rsa(Authctxt *authctxt, BIGNUM *client_n)
{
struct ssh *ssh = active_state;
struct sshkey *key;
char *fp;
struct passwd *pw = authctxt->pw;
/* no user given */
if (!authctxt->valid)
return 0;
if (!PRIVSEP(auth_rsa_key_allowed(pw, client_n, &key))) {
auth_clear_options();
return (0);
}
/* Perform the challenge-response dialog for this key. */
if (!auth_rsa_challenge_dialog(key)) {
/* Wrong response. */
verbose("Wrong response to RSA authentication challenge.");
ssh_packet_send_debug(ssh,
"Wrong response to RSA authentication challenge.");
/*
* Break out of the loop. Otherwise we might send
* another challenge and break the protocol.
*/
sshkey_free(key);
return (0);
}
/*
* Correct response. The client has been successfully
* authenticated. Note that we have not yet processed the
* options; this will be reset if the options cause the
* authentication to be rejected.
*/
fp = sshkey_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
verbose("Found matching %s key: %s",
sshkey_type(key), fp);
xfree(fp);
sshkey_free(key);
ssh_packet_send_debug(ssh, "RSA authentication accepted.");
return (1);
}
/* Checks whether a key has already been previously used for authentication */
int
auth2_key_already_used(Authctxt *authctxt, const struct sshkey *key)
{
u_int i;
char *fp;
for (i = 0; i < authctxt->nprev_keys; i++) {
if (sshkey_equal_public(key, authctxt->prev_keys[i])) {
fp = sshkey_fingerprint(authctxt->prev_keys[i],
options.fingerprint_hash, SSH_FP_DEFAULT);
debug3("%s: key already used: %s %s", __func__,
sshkey_type(authctxt->prev_keys[i]),
fp == NULL ? "UNKNOWN" : fp);
free(fp);
return 1;
}
}
return 0;
}
static void
warn_changed_key(struct sshkey *host_key)
{
char *fp;
fp = sshkey_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
error("It is also possible that a host key has just been changed.");
error("The fingerprint for the %s key sent by the remote host is\n%s.",
sshkey_type(host_key), fp);
error("Please contact your system administrator.");
xfree(fp);
}
/* returns 0 if key verifies or -1 if key does NOT verify */
int
verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
{
int r = -1, flags = 0;
char *fp = NULL;
struct sshkey *plain = NULL;
if ((fp = sshkey_fingerprint(host_key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
error("%s: fingerprint host key: %s", __func__, ssh_err(r));
r = -1;
goto out;
}
debug("Server host key: %s %s",
compat20 ? sshkey_ssh_name(host_key) : sshkey_type(host_key), fp);
if (sshkey_equal(previous_host_key, host_key)) {
debug2("%s: server host key %s %s matches cached key",
__func__, sshkey_type(host_key), fp);
r = 0;
goto out;
}
/* Check in RevokedHostKeys file if specified */
if (options.revoked_host_keys != NULL) {
r = sshkey_check_revoked(host_key, options.revoked_host_keys);
switch (r) {
case 0:
break; /* not revoked */
case SSH_ERR_KEY_REVOKED:
error("Host key %s %s revoked by file %s",
sshkey_type(host_key), fp,
options.revoked_host_keys);
r = -1;
goto out;
default:
error("Error checking host key %s %s in "
"revoked keys file %s: %s", sshkey_type(host_key),
fp, options.revoked_host_keys, ssh_err(r));
r = -1;
goto out;
}
}
if (options.verify_host_key_dns) {
/*
* XXX certs are not yet supported for DNS, so downgrade
* them and try the plain key.
*/
if ((r = sshkey_from_private(host_key, &plain)) != 0)
goto out;
if (sshkey_is_cert(plain))
sshkey_drop_cert(plain);
if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
if (flags & DNS_VERIFY_FOUND) {
if (options.verify_host_key_dns == 1 &&
flags & DNS_VERIFY_MATCH &&
flags & DNS_VERIFY_SECURE) {
r = 0;
goto out;
}
if (flags & DNS_VERIFY_MATCH) {
matching_host_key_dns = 1;
} else {
warn_changed_key(plain);
error("Update the SSHFP RR in DNS "
"with the new host key to get rid "
"of this message.");
}
}
}
}
r = check_host_key(host, hostaddr, options.port, host_key, RDRW,
options.user_hostfiles, options.num_user_hostfiles,
options.system_hostfiles, options.num_system_hostfiles);
out:
sshkey_free(plain);
free(fp);
if (r == 0 && host_key != NULL) {
key_free(previous_host_key);
previous_host_key = key_from_private(host_key);
}
return r;
}
void
load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
{
FILE *f;
char line[8192];
u_long linenum = 0, num_loaded = 0;
char *cp, *cp2, *hashed_host;
HostkeyMarker marker;
struct sshkey *key;
u_int kbits;
if ((f = fopen(path, "r")) == NULL)
return;
debug3("%s: loading entries for host \"%.100s\" from file \"%s\"",
__func__, host, path);
while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) {
cp = line;
/* Skip any leading whitespace, comments and empty lines. */
for (; *cp == ' ' || *cp == '\t'; cp++)
;
if (!*cp || *cp == '#' || *cp == '\n')
continue;
if ((marker = check_markers(&cp)) == MRK_ERROR) {
verbose("%s: invalid marker at %s:%lu",
__func__, path, linenum);
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 %lu of %s",
linenum, path);
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 ((key = sshkey_new(KEY_UNSPEC)) == NULL) {
error("%s: sshkey_new failed", __func__);
break;
}
if (!hostfile_read_key(&cp, &kbits, key)) {
sshkey_free(key);
if ((key = sshkey_new(KEY_RSA1)) == NULL) {
error("%s: sshkey_new failed", __func__);
break;
}
if (!hostfile_read_key(&cp, &kbits, key)) {
sshkey_free(key);
continue;
}
}
if (!hostfile_check_key(kbits, key, host, path, linenum))
continue;
debug3("%s: found %skey type %s in file %s:%lu", __func__,
marker == MRK_NONE ? "" :
(marker == MRK_CA ? "ca " : "revoked "),
sshkey_type(key), path, linenum);
hostkeys->entries = xrealloc(hostkeys->entries,
hostkeys->num_entries + 1, sizeof(*hostkeys->entries));
hostkeys->entries[hostkeys->num_entries].host = xstrdup(host);
hostkeys->entries[hostkeys->num_entries].file = xstrdup(path);
hostkeys->entries[hostkeys->num_entries].line = linenum;
hostkeys->entries[hostkeys->num_entries].key = key;
hostkeys->entries[hostkeys->num_entries].marker = marker;
hostkeys->num_entries++;
num_loaded++;
}
debug3("%s: loaded %lu keys", __func__, num_loaded);
fclose(f);
return;
}
/* return 1 if given hostkey is allowed */
int
hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
struct sshkey *key)
{
struct ssh *ssh = active_state; /* XXX */
const char *resolvedname, *ipaddr, *lookup, *reason;
HostStatus host_status;
int len;
char *fp;
if (auth_key_is_revoked(key))
return 0;
resolvedname = auth_get_canonical_hostname(ssh, options.use_dns);
ipaddr = ssh_remote_ipaddr(ssh);
debug2("%s: chost %s resolvedname %s ipaddr %s", __func__,
chost, resolvedname, ipaddr);
if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
debug2("stripping trailing dot from chost %s", chost);
chost[len - 1] = '\0';
}
if (options.hostbased_uses_name_from_packet_only) {
if (auth_rhosts2(pw, cuser, chost, chost) == 0) {
debug2("%s: auth_rhosts2 refused "
"user \"%.100s\" host \"%.100s\" (from packet)",
__func__, cuser, chost);
return 0;
}
lookup = chost;
} else {
if (strcasecmp(resolvedname, chost) != 0)
logit("userauth_hostbased mismatch: "
"client sends %s, but we resolve %s to %s",
chost, ipaddr, resolvedname);
if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0) {
debug2("%s: auth_rhosts2 refused "
"user \"%.100s\" host \"%.100s\" addr \"%.100s\"",
__func__, cuser, resolvedname, ipaddr);
return 0;
}
lookup = resolvedname;
}
debug2("%s: access allowed by auth_rhosts2", __func__);
if (sshkey_is_cert(key) &&
sshkey_cert_check_authority(key, 1, 0, lookup, &reason)) {
error("%s", reason);
auth_debug_add("%s", reason);
return 0;
}
host_status = check_key_in_hostfiles(pw, key, lookup,
_PATH_SSH_SYSTEM_HOSTFILE,
options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
/* backward compat if no key has been found. */
if (host_status == HOST_NEW) {
host_status = check_key_in_hostfiles(pw, key, lookup,
_PATH_SSH_SYSTEM_HOSTFILE2,
options.ignore_user_known_hosts ? NULL :
_PATH_SSH_USER_HOSTFILE2);
}
if (host_status == HOST_OK) {
if (sshkey_is_cert(key)) {
if ((fp = sshkey_fingerprint(key->cert->signature_key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
fatal("%s: sshkey_fingerprint fail", __func__);
verbose("Accepted certificate ID \"%s\" signed by "
"%s CA %s from %s@%s", key->cert->key_id,
sshkey_type(key->cert->signature_key), fp,
cuser, lookup);
} else {
if ((fp = sshkey_fingerprint(key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
fatal("%s: sshkey_fingerprint fail", __func__);
verbose("Accepted %s public key %s from %s@%s",
sshkey_type(key), fp, cuser, lookup);
}
free(fp);
}
return (host_status == HOST_OK);
}
static int
check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
struct sshkey *host_key, int readonly,
char **user_hostfiles, u_int num_user_hostfiles,
char **system_hostfiles, u_int num_system_hostfiles)
{
HostStatus host_status;
HostStatus ip_status;
struct sshkey *raw_key = NULL;
char *ip = NULL, *host = NULL;
char hostline[1000], *hostp, *fp, *ra;
char msg[1024];
const char *type;
const struct hostkey_entry *host_found, *ip_found;
int len, cancelled_forwarding = 0;
int local = sockaddr_is_local(hostaddr);
int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0;
struct hostkeys *host_hostkeys, *ip_hostkeys;
u_int i;
/*
* Force accepting of the host key for loopback/localhost. The
* problem is that if the home directory is NFS-mounted to multiple
* machines, localhost will refer to a different machine in each of
* them, and the user will get bogus HOST_CHANGED warnings. This
* essentially disables host authentication for localhost; however,
* this is probably not a real problem.
*/
if (options.no_host_authentication_for_localhost == 1 && local &&
options.host_key_alias == NULL) {
debug("Forcing accepting of host key for "
"loopback/localhost.");
return 0;
}
/*
* Prepare the hostname and address strings used for hostkey lookup.
* In some cases, these will have a port number appended.
*/
get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
/*
* Turn off check_host_ip if the connection is to localhost, via proxy
* command or if we don't have a hostname to compare with
*/
if (options.check_host_ip && (local ||
strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
options.check_host_ip = 0;
host_hostkeys = init_hostkeys();
for (i = 0; i < num_user_hostfiles; i++)
load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
ip_hostkeys = NULL;
if (!want_cert && options.check_host_ip) {
ip_hostkeys = init_hostkeys();
for (i = 0; i < num_user_hostfiles; i++)
load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
}
retry:
/* Reload these as they may have changed on cert->key downgrade */
want_cert = sshkey_is_cert(host_key);
type = sshkey_type(host_key);
/*
* Check if the host key is present in the user's list of known
* hosts or in the systemwide list.
*/
host_status = check_key_in_hostkeys(host_hostkeys, host_key,
&host_found);
/*
* Also perform check for the ip address, skip the check if we are
* localhost, looking for a certificate, or the hostname was an ip
* address to begin with.
*/
if (!want_cert && ip_hostkeys != NULL) {
ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
&ip_found);
if (host_status == HOST_CHANGED &&
(ip_status != HOST_CHANGED ||
(ip_found != NULL &&
!sshkey_equal(ip_found->key, host_found->key))))
host_ip_differ = 1;
} else
ip_status = host_status;
switch (host_status) {
case HOST_OK:
/* The host is known and the key matches. */
debug("Host '%.200s' is known and matches the %s host %s.",
host, type, want_cert ? "certificate" : "key");
debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
host_found->file, host_found->line);
if (want_cert && !check_host_cert(hostname, host_key))
goto fail;
if (options.check_host_ip && ip_status == HOST_NEW) {
if (readonly || want_cert)
logit("%s host key for IP address "
"'%.128s' not in list of known hosts.",
type, ip);
else if (!add_host_to_hostfile(user_hostfiles[0], ip,
host_key, options.hash_known_hosts))
logit("Failed to add the %s host key for IP "
"address '%.128s' to the list of known "
"hosts (%.30s).", type, ip,
user_hostfiles[0]);
else
logit("Warning: Permanently added the %s host "
"key for IP address '%.128s' to the list "
"of known hosts.", type, ip);
} else if (options.visual_host_key) {
fp = sshkey_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_HEX);
ra = sshkey_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_RANDOMART);
logit("Host key fingerprint is %s\n%s\n", fp, ra);
xfree(ra);
xfree(fp);
}
break;
case HOST_NEW:
if (options.host_key_alias == NULL && port != 0 &&
port != SSH_DEFAULT_PORT) {
debug("checking without port identifier");
if (check_host_key(hostname, hostaddr, 0, host_key,
ROQUIET, user_hostfiles, num_user_hostfiles,
system_hostfiles, num_system_hostfiles) == 0) {
debug("found matching key w/out port");
break;
}
}
if (readonly || want_cert)
goto fail;
/* The host is new. */
if (options.strict_host_key_checking == 1) {
/*
* User has requested strict host key checking. We
* will not add the host key automatically. The only
* alternative left is to abort.
*/
error("No %s host key is known for %.200s and you "
"have requested strict checking.", type, host);
goto fail;
} else if (options.strict_host_key_checking == 2) {
char msg1[1024], msg2[1024];
if (show_other_keys(host_hostkeys, host_key))
snprintf(msg1, sizeof(msg1),
"\nbut keys of different type are already"
" known for this host.");
else
snprintf(msg1, sizeof(msg1), ".");
/* The default */
fp = sshkey_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_HEX);
ra = sshkey_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_RANDOMART);
msg2[0] = '\0';
if (options.verify_host_key_dns) {
if (matching_host_key_dns)
snprintf(msg2, sizeof(msg2),
"Matching host key fingerprint"
" found in DNS.\n");
else
snprintf(msg2, sizeof(msg2),
"No matching host key fingerprint"
" found in DNS.\n");
}
snprintf(msg, sizeof(msg),
"The authenticity of host '%.200s (%s)' can't be "
"established%s\n"
"%s key fingerprint is %s.%s%s\n%s"
"Are you sure you want to continue connecting "
"(yes/no)? ",
host, ip, msg1, type, fp,
options.visual_host_key ? "\n" : "",
options.visual_host_key ? ra : "",
msg2);
xfree(ra);
xfree(fp);
if (!confirm(msg))
goto fail;
}
/*
* If not in strict mode, add the key automatically to the
* local known_hosts file.
*/
if (options.check_host_ip && ip_status == HOST_NEW) {
snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
hostp = hostline;
if (options.hash_known_hosts) {
/* Add hash of host and IP separately */
r = add_host_to_hostfile(user_hostfiles[0],
host, host_key, options.hash_known_hosts) &&
add_host_to_hostfile(user_hostfiles[0], ip,
host_key, options.hash_known_hosts);
} else {
/* Add unhashed "host,ip" */
r = add_host_to_hostfile(user_hostfiles[0],
hostline, host_key,
options.hash_known_hosts);
}
} else {
r = add_host_to_hostfile(user_hostfiles[0], host,
host_key, options.hash_known_hosts);
hostp = host;
}
if (!r)
logit("Failed to add the host to the list of known "
"hosts (%.500s).", user_hostfiles[0]);
else
logit("Warning: Permanently added '%.200s' (%s) to the "
"list of known hosts.", hostp, type);
break;
case HOST_REVOKED:
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: REVOKED HOST KEY DETECTED! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("The %s host key for %s is marked as revoked.", type, host);
error("This could mean that a stolen key is being used to");
error("impersonate this host.");
/*
* If strict host key checking is in use, the user will have
* to edit the key manually and we can only abort.
*/
if (options.strict_host_key_checking) {
error("%s host key for %.200s was revoked and you have "
"requested strict checking.", type, host);
goto fail;
}
goto continue_unsafe;
case HOST_CHANGED:
if (want_cert) {
/*
* This is only a debug() since it is valid to have
* CAs with wildcard DNS matches that don't match
* all hosts that one might visit.
*/
debug("Host certificate authority does not "
"match %s in %s:%lu", CA_MARKER,
host_found->file, host_found->line);
goto fail;
}
if (readonly == ROQUIET)
goto fail;
if (options.check_host_ip && host_ip_differ) {
char *key_msg;
if (ip_status == HOST_NEW)
key_msg = "is unknown";
else if (ip_status == HOST_OK)
key_msg = "is unchanged";
else
key_msg = "has a different value";
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("The %s host key for %s has changed,", type, host);
error("and the key for the corresponding IP address %s", ip);
error("%s. This could either mean that", key_msg);
error("DNS SPOOFING is happening or the IP address for the host");
error("and its host key have changed at the same time.");
if (ip_status != HOST_NEW)
error("Offending key for IP in %s:%lu",
ip_found->file, ip_found->line);
}
/* The host key has changed. */
warn_changed_key(host_key);
error("Add correct host key in %.100s to get rid of this message.",
user_hostfiles[0]);
error("Offending %s key in %s:%lu",
sshkey_type(host_found->key),
host_found->file, host_found->line);
/*
* If strict host key checking is in use, the user will have
* to edit the key manually and we can only abort.
*/
if (options.strict_host_key_checking) {
error("%s host key for %.200s has changed and you have "
"requested strict checking.", type, host);
goto fail;
}
continue_unsafe:
/*
* If strict host key checking has not been requested, allow
* the connection but without MITM-able authentication or
* forwarding.
*/
if (options.password_authentication) {
error("Password authentication is disabled to avoid "
"man-in-the-middle attacks.");
options.password_authentication = 0;
cancelled_forwarding = 1;
}
if (options.kbd_interactive_authentication) {
error("Keyboard-interactive authentication is disabled"
" to avoid man-in-the-middle attacks.");
options.kbd_interactive_authentication = 0;
options.challenge_response_authentication = 0;
cancelled_forwarding = 1;
}
if (options.challenge_response_authentication) {
error("Challenge/response authentication is disabled"
" to avoid man-in-the-middle attacks.");
options.challenge_response_authentication = 0;
cancelled_forwarding = 1;
}
if (options.forward_agent) {
error("Agent forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.forward_agent = 0;
cancelled_forwarding = 1;
}
if (options.forward_x11) {
error("X11 forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.forward_x11 = 0;
cancelled_forwarding = 1;
}
if (options.num_local_forwards > 0 ||
options.num_remote_forwards > 0) {
error("Port forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.num_local_forwards =
options.num_remote_forwards = 0;
cancelled_forwarding = 1;
}
if (options.tun_open != SSH_TUNMODE_NO) {
error("Tunnel forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.tun_open = SSH_TUNMODE_NO;
cancelled_forwarding = 1;
}
if (options.exit_on_forward_failure && cancelled_forwarding)
fatal("Error: forwarding disabled due to host key "
"check failure");
/*
* XXX Should permit the user to change to use the new id.
* This could be done by converting the host key to an
* identifying sentence, tell that the host identifies itself
* by that sentence, and ask the user if he/she wishes to
* accept the authentication.
*/
break;
case HOST_FOUND:
fatal("internal error");
break;
}
if (options.check_host_ip && host_status != HOST_CHANGED &&
ip_status == HOST_CHANGED) {
snprintf(msg, sizeof(msg),
"Warning: the %s host key for '%.200s' "
"differs from the key for the IP address '%.128s'"
"\nOffending key for IP in %s:%lu",
type, host, ip, ip_found->file, ip_found->line);
if (host_status == HOST_OK) {
len = strlen(msg);
snprintf(msg + len, sizeof(msg) - len,
"\nMatching host key in %s:%lu",
host_found->file, host_found->line);
}
if (options.strict_host_key_checking == 1) {
logit("%s", msg);
error("Exiting, you have requested strict checking.");
goto fail;
} else if (options.strict_host_key_checking == 2) {
strlcat(msg, "\nAre you sure you want "
"to continue connecting (yes/no)? ", sizeof(msg));
if (!confirm(msg))
goto fail;
} else {
logit("%s", msg);
}
}
xfree(ip);
xfree(host);
if (host_hostkeys != NULL)
free_hostkeys(host_hostkeys);
if (ip_hostkeys != NULL)
free_hostkeys(ip_hostkeys);
return 0;
fail:
if (want_cert && host_status != HOST_REVOKED) {
/*
* No matching certificate. Downgrade cert to raw key and
* search normally.
*/
debug("No matching CA found. Retry with plain key");
if ((r = sshkey_from_private(host_key, &raw_key)) != 0)
fatal("%s: sshkey_from_private: %s",
__func__, ssh_err(r));
if ((r = sshkey_drop_cert(raw_key)) != 0)
fatal("Couldn't drop certificate: %s", ssh_err(r));
host_key = raw_key;
goto retry;
}
if (raw_key != NULL)
sshkey_free(raw_key);
xfree(ip);
xfree(host);
if (host_hostkeys != NULL)
free_hostkeys(host_hostkeys);
if (ip_hostkeys != NULL)
free_hostkeys(ip_hostkeys);
return -1;
}
static int
userauth_hostbased(struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
struct sshbuf *b;
struct sshkey *key = NULL;
char *pkalg, *cuser, *chost;
u_char *pkblob, *sig;
size_t alen, blen, slen;
int r, pktype, authenticated = 0;
if (!authctxt->valid) {
debug2("%s: disabled because of invalid user", __func__);
return 0;
}
/* XXX use sshkey_froms() */
if ((r = sshpkt_get_cstring(ssh, &pkalg, &alen)) != 0 ||
(r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 ||
(r = sshpkt_get_cstring(ssh, &chost, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &cuser, NULL)) != 0 ||
(r = sshpkt_get_string(ssh, &sig, &slen)) != 0)
fatal("%s: packet parsing: %s", __func__, ssh_err(r));
debug("%s: cuser %s chost %s pkalg %s slen %zu", __func__,
cuser, chost, pkalg, slen);
#ifdef DEBUG_PK
debug("signature:");
sshbuf_dump_data(sig, siglen, stderr);
#endif
pktype = sshkey_type_from_name(pkalg);
if (pktype == KEY_UNSPEC) {
/* this is perfectly legal */
logit("%s: unsupported public key algorithm: %s",
__func__, pkalg);
goto done;
}
if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) {
error("%s: key_from_blob: %s", __func__, ssh_err(r));
goto done;
}
if (key == NULL) {
error("%s: cannot decode key: %s", __func__, pkalg);
goto done;
}
if (key->type != pktype) {
error("%s: type mismatch for decoded key "
"(received %d, expected %d)", __func__, key->type, pktype);
goto done;
}
if (sshkey_type_plain(key->type) == KEY_RSA &&
(ssh->compat & SSH_BUG_RSASIGMD5) != 0) {
error("Refusing RSA key because peer uses unsafe "
"signature format");
goto done;
}
if (match_pattern_list(sshkey_ssh_name(key),
options.hostbased_key_types, 0) != 1) {
logit("%s: key type %s not in HostbasedAcceptedKeyTypes",
__func__, sshkey_type(key));
goto done;
}
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
/* reconstruct packet */
if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 ||
(r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
(r = sshbuf_put_cstring(b, authctxt->user)) != 0 ||
(r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
(r = sshbuf_put_cstring(b, "hostbased")) != 0 ||
(r = sshbuf_put_string(b, pkalg, alen)) != 0 ||
(r = sshbuf_put_string(b, pkblob, blen)) != 0 ||
(r = sshbuf_put_cstring(b, chost)) != 0 ||
(r = sshbuf_put_cstring(b, cuser)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
#ifdef DEBUG_PK
sshbuf_dump(b, stderr);
#endif
auth2_record_info(authctxt,
"client user \"%.100s\", client host \"%.100s\"", cuser, chost);
/* test for allowed key and correct signature */
authenticated = 0;
if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
PRIVSEP(sshkey_verify(key, sig, slen,
sshbuf_ptr(b), sshbuf_len(b), pkalg, ssh->compat)) == 0)
authenticated = 1;
auth2_record_key(authctxt, authenticated, key);
sshbuf_free(b);
done:
debug2("%s: authenticated %d", __func__, authenticated);
sshkey_free(key);
free(pkalg);
free(pkblob);
free(cuser);
free(chost);
free(sig);
return authenticated;
}
/* returns 0 if key verifies or -1 if key does NOT verify */
int
verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key)
{
u_int i;
int r = -1, flags = 0;
char valid[64], *fp = NULL, *cafp = NULL;
struct sshkey *plain = NULL;
if ((fp = sshkey_fingerprint(host_key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
error("%s: fingerprint host key: %s", __func__, ssh_err(r));
r = -1;
goto out;
}
if (sshkey_is_cert(host_key)) {
if ((cafp = sshkey_fingerprint(host_key->cert->signature_key,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
error("%s: fingerprint CA key: %s",
__func__, ssh_err(r));
r = -1;
goto out;
}
sshkey_format_cert_validity(host_key->cert,
valid, sizeof(valid));
debug("Server host certificate: %s %s, serial %llu "
"ID \"%s\" CA %s %s valid %s",
sshkey_ssh_name(host_key), fp,
(unsigned long long)host_key->cert->serial,
host_key->cert->key_id,
sshkey_ssh_name(host_key->cert->signature_key), cafp,
valid);
for (i = 0; i < host_key->cert->nprincipals; i++) {
debug2("Server host certificate hostname: %s",
host_key->cert->principals[i]);
}
} else {
debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp);
}
if (sshkey_equal(previous_host_key, host_key)) {
debug2("%s: server host key %s %s matches cached key",
__func__, sshkey_type(host_key), fp);
r = 0;
goto out;
}
/* Check in RevokedHostKeys file if specified */
if (options.revoked_host_keys != NULL) {
r = sshkey_check_revoked(host_key, options.revoked_host_keys);
switch (r) {
case 0:
break; /* not revoked */
case SSH_ERR_KEY_REVOKED:
error("Host key %s %s revoked by file %s",
sshkey_type(host_key), fp,
options.revoked_host_keys);
r = -1;
goto out;
default:
error("Error checking host key %s %s in "
"revoked keys file %s: %s", sshkey_type(host_key),
fp, options.revoked_host_keys, ssh_err(r));
r = -1;
goto out;
}
}
if (options.verify_host_key_dns) {
/*
* XXX certs are not yet supported for DNS, so downgrade
* them and try the plain key.
*/
if ((r = sshkey_from_private(host_key, &plain)) != 0)
goto out;
if (sshkey_is_cert(plain))
sshkey_drop_cert(plain);
if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
if (flags & DNS_VERIFY_FOUND) {
if (options.verify_host_key_dns == 1 &&
flags & DNS_VERIFY_MATCH &&
flags & DNS_VERIFY_SECURE) {
r = 0;
goto out;
}
if (flags & DNS_VERIFY_MATCH) {
matching_host_key_dns = 1;
} else {
warn_changed_key(plain);
error("Update the SSHFP RR in DNS "
"with the new host key to get rid "
"of this message.");
}
}
}
}
r = check_host_key(host, hostaddr, options.port, host_key, RDRW,
options.user_hostfiles, options.num_user_hostfiles,
options.system_hostfiles, options.num_system_hostfiles);
out:
sshkey_free(plain);
free(fp);
free(cafp);
if (r == 0 && host_key != NULL) {
sshkey_free(previous_host_key);
r = sshkey_from_private(host_key, &previous_host_key);
}
return r;
}
static int
userauth_pubkey(Authctxt *authctxt)
{
Buffer b;
Key *key = NULL;
char *pkalg, *userstyle, *fp = NULL;
u_char *pkblob, *sig;
u_int alen, blen, slen;
int have_sig, pktype;
int authenticated = 0;
if (!authctxt->valid) {
debug2("%s: disabled because of invalid user", __func__);
return 0;
}
have_sig = packet_get_char();
if (datafellows & SSH_BUG_PKAUTH) {
debug2("%s: SSH_BUG_PKAUTH", __func__);
/* no explicit pkalg given */
pkblob = packet_get_string(&blen);
buffer_init(&b);
buffer_append(&b, pkblob, blen);
/* so we have to extract the pkalg from the pkblob */
pkalg = buffer_get_string(&b, &alen);
buffer_free(&b);
} else {
pkalg = packet_get_string(&alen);
pkblob = packet_get_string(&blen);
}
pktype = key_type_from_name(pkalg);
if (pktype == KEY_UNSPEC) {
/* this is perfectly legal */
logit("%s: unsupported public key algorithm: %s",
__func__, pkalg);
goto done;
}
key = key_from_blob(pkblob, blen);
if (key == NULL) {
error("%s: cannot decode key: %s", __func__, pkalg);
goto done;
}
if (key->type != pktype) {
error("%s: type mismatch for decoded key "
"(received %d, expected %d)", __func__, key->type, pktype);
goto done;
}
if (key_type_plain(key->type) == KEY_RSA &&
(datafellows & SSH_BUG_RSASIGMD5) != 0) {
logit("Refusing RSA key because client uses unsafe "
"signature scheme");
goto done;
}
fp = sshkey_fingerprint(key, options.fingerprint_hash, SSH_FP_DEFAULT);
if (auth2_userkey_already_used(authctxt, key)) {
logit("refusing previously-used %s key", key_type(key));
goto done;
}
if (match_pattern_list(sshkey_ssh_name(key),
options.pubkey_key_types, 0) != 1) {
logit("%s: key type %s not in PubkeyAcceptedKeyTypes",
__func__, sshkey_ssh_name(key));
goto done;
}
if (have_sig) {
debug3("%s: have signature for %s %s",
__func__, sshkey_type(key), fp);
sig = packet_get_string(&slen);
packet_check_eom();
buffer_init(&b);
if (datafellows & SSH_OLD_SESSIONID) {
buffer_append(&b, session_id2, session_id2_len);
} else {
buffer_put_string(&b, session_id2, session_id2_len);
}
/* reconstruct packet */
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
xasprintf(&userstyle, "%s%s%s", authctxt->user,
authctxt->style ? ":" : "",
authctxt->style ? authctxt->style : "");
buffer_put_cstring(&b, userstyle);
free(userstyle);
buffer_put_cstring(&b,
datafellows & SSH_BUG_PKSERVICE ?
"ssh-userauth" :
authctxt->service);
if (datafellows & SSH_BUG_PKAUTH) {
buffer_put_char(&b, have_sig);
} else {
buffer_put_cstring(&b, "publickey");
buffer_put_char(&b, have_sig);
buffer_put_cstring(&b, pkalg);
}
buffer_put_string(&b, pkblob, blen);
#ifdef DEBUG_PK
buffer_dump(&b);
#endif
pubkey_auth_info(authctxt, key, NULL);
/* test for correct signature */
authenticated = 0;
if (PRIVSEP(user_key_allowed(authctxt->pw, key, 1)) &&
PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
buffer_len(&b))) == 1) {
authenticated = 1;
/* Record the successful key to prevent reuse */
auth2_record_userkey(authctxt, key);
key = NULL; /* Don't free below */
}
buffer_free(&b);
free(sig);
} else {
debug("%s: test whether pkalg/pkblob are acceptable for %s %s",
__func__, sshkey_type(key), fp);
packet_check_eom();
/* XXX fake reply and always send PK_OK ? */
/*
* XXX this allows testing whether a user is allowed
* to login: if you happen to have a valid pubkey this
* message is sent. the message is NEVER sent at all
* if a user is not allowed to login. is this an
* issue? -markus
*/
if (PRIVSEP(user_key_allowed(authctxt->pw, key, 0))) {
packet_start(SSH2_MSG_USERAUTH_PK_OK);
packet_put_string(pkalg, alen);
packet_put_string(pkblob, blen);
packet_send();
packet_write_wait();
authctxt->postponed = 1;
}
}
if (authenticated != 1)
auth_clear_options();
done:
debug2("%s: authenticated %d pkalg %s", __func__, authenticated, pkalg);
if (key != NULL)
key_free(key);
free(pkalg);
free(pkblob);
free(fp);
return authenticated;
}
int
main(int argc, char **argv)
{
struct sshbuf *b;
Options options;
#define NUM_KEYTYPES 4
struct sshkey *keys[NUM_KEYTYPES], *key = NULL;
struct passwd *pw;
int r, key_fd[NUM_KEYTYPES], i, found, version = 2, fd;
u_char *signature, *data, rver;
char *host, *fp;
size_t slen, dlen;
#ifdef WITH_OPENSSL
u_int32_t rnd[256];
#endif
if (pledge("stdio rpath getpw dns id", NULL) != 0)
fatal("%s: pledge: %s", __progname, strerror(errno));
/* 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;
/* XXX This really needs to read sshd_config for the paths */
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_ED25519_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);
seed_rng();
#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, pw, "", "", &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");
#ifdef WITH_OPENSSL
OpenSSL_add_all_algorithms();
arc4random_buf(rnd, sizeof(rnd));
RAND_seed(rnd, sizeof(rnd));
#endif
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
keys[i] = NULL;
if (key_fd[i] == -1)
continue;
r = sshkey_load_private_type_fd(key_fd[i], KEY_UNSPEC,
NULL, &key, NULL);
close(key_fd[i]);
if (r != 0)
debug("parse key %d: %s", i, ssh_err(r));
else if (key != NULL) {
keys[i] = key;
found = 1;
}
}
if (!found)
fatal("no hostkey found");
if (pledge("stdio dns", NULL) != 0)
fatal("%s: pledge: %s", __progname, strerror(errno));
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __progname);
if (ssh_msg_recv(STDIN_FILENO, b) < 0)
fatal("ssh_msg_recv failed");
if ((r = sshbuf_get_u8(b, &rver)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (rver != version)
fatal("bad version: received %d, expected %d", rver, version);
if ((r = sshbuf_get_u32(b, (u_int *)&fd)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (fd < 0 || fd == STDIN_FILENO || fd == STDOUT_FILENO)
fatal("bad fd");
if ((host = get_local_name(fd)) == NULL)
fatal("cannot get local name for fd");
if ((r = sshbuf_get_string(b, &data, &dlen)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (valid_request(pw, host, &key, data, dlen) < 0)
fatal("not a valid request");
free(host);
found = 0;
for (i = 0; i < NUM_KEYTYPES; i++) {
if (keys[i] != NULL &&
sshkey_equal_public(key, keys[i])) {
found = 1;
break;
}
}
if (!found) {
if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL)
fatal("%s: sshkey_fingerprint failed", __progname);
fatal("no matching hostkey found for key %s %s",
sshkey_type(key), fp ? fp : "");
}
if ((r = sshkey_sign(keys[i], &signature, &slen, data, dlen, NULL, 0))
!= 0)
fatal("sshkey_sign failed: %s", ssh_err(r));
free(data);
/* send reply */
sshbuf_reset(b);
if ((r = sshbuf_put_string(b, signature, slen)) != 0)
fatal("%s: buffer error: %s", __progname, ssh_err(r));
if (ssh_msg_send(STDOUT_FILENO, version, b) == -1)
fatal("ssh_msg_send failed");
return (0);
}
static int
server_input_hostkeys_prove(struct sshbuf **respp)
{
struct ssh *ssh = active_state; /* XXX */
struct sshbuf *resp = NULL;
struct sshbuf *sigbuf = NULL;
struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
int r, ndx, success = 0;
const u_char *blob;
u_char *sig = 0;
size_t blen, slen;
if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new", __func__);
while (ssh_packet_remaining(ssh) > 0) {
sshkey_free(key);
key = NULL;
if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
(r = sshkey_from_blob(blob, blen, &key)) != 0) {
error("%s: couldn't parse key: %s",
__func__, ssh_err(r));
goto out;
}
/*
* Better check that this is actually one of our hostkeys
* before attempting to sign anything with it.
*/
if ((ndx = ssh->kex->host_key_index(key, 1, ssh)) == -1) {
error("%s: unknown host %s key",
__func__, sshkey_type(key));
goto out;
}
/*
* XXX refactor: make kex->sign just use an index rather
* than passing in public and private keys
*/
if ((key_prv = get_hostkey_by_index(ndx)) == NULL &&
(key_pub = get_hostkey_public_by_index(ndx, ssh)) == NULL) {
error("%s: can't retrieve hostkey %d", __func__, ndx);
goto out;
}
sshbuf_reset(sigbuf);
free(sig);
sig = NULL;
if ((r = sshbuf_put_cstring(sigbuf,
"*****@*****.**")) != 0 ||
(r = sshbuf_put_string(sigbuf,
ssh->kex->session_id, ssh->kex->session_id_len)) != 0 ||
(r = sshkey_puts(key, sigbuf)) != 0 ||
(r = ssh->kex->sign(key_prv, key_pub, &sig, &slen,
sshbuf_ptr(sigbuf), sshbuf_len(sigbuf), 0)) != 0 ||
(r = sshbuf_put_string(resp, sig, slen)) != 0) {
error("%s: couldn't prepare signature: %s",
__func__, ssh_err(r));
goto out;
}
}
/* Success */
*respp = resp;
resp = NULL; /* don't free it */
success = 1;
out:
free(sig);
sshbuf_free(resp);
sshbuf_free(sigbuf);
sshkey_free(key);
return success;
}
