-/* $OpenBSD: readconf.c,v 1.345 2020/12/21 09:19:53 djm Exp $ */
+/* $OpenBSD: readconf.c,v 1.346 2020/12/22 00:15:22 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys,
oFingerprintHash, oUpdateHostkeys, oHostbasedKeyTypes,
oPubkeyAcceptedKeyTypes, oCASignatureAlgorithms, oProxyJump,
- oSecurityKeyProvider,
+ oSecurityKeyProvider, oKnownHostsCommand,
oIgnore, oIgnoredUnknownOption, oDeprecated, oUnsupported
} OpCodes;
{ "ignoreunknown", oIgnoreUnknown },
{ "proxyjump", oProxyJump },
{ "securitykeyprovider", oSecurityKeyProvider },
+ { "knownhostscommand", oKnownHostsCommand },
{ NULL, oBadOption }
};
charptr = &options->sk_provider;
goto parse_string;
+ case oKnownHostsCommand:
+ charptr = &options->known_hosts_command;
+ goto parse_command;
+
case oProxyCommand:
charptr = &options->proxy_command;
/* Ignore ProxyCommand if ProxyJump already specified */
options->update_hostkeys = -1;
options->hostbased_key_types = NULL;
options->pubkey_key_types = NULL;
+ options->known_hosts_command = NULL;
}
/*
CLEAR_ON_NONE(options->revoked_host_keys);
CLEAR_ON_NONE(options->pkcs11_provider);
CLEAR_ON_NONE(options->sk_provider);
+ CLEAR_ON_NONE(options->known_hosts_command);
if (options->jump_host != NULL &&
strcmp(options->jump_host, "none") == 0 &&
options->jump_port == 0 && options->jump_user == NULL) {
dump_cfg_string(oPubkeyAcceptedKeyTypes, o->pubkey_key_types);
dump_cfg_string(oRevokedHostKeys, o->revoked_host_keys);
dump_cfg_string(oXAuthLocation, o->xauth_location);
+ dump_cfg_string(oKnownHostsCommand, o->known_hosts_command);
/* Forwards */
dump_cfg_forwards(oDynamicForward, o->num_local_forwards, o->local_forwards);
-/* $OpenBSD: readconf.h,v 1.136 2020/12/17 23:10:27 djm Exp $ */
+/* $OpenBSD: readconf.h,v 1.137 2020/12/22 00:15:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
int jump_port;
char *jump_extra;
+ char *known_hosts_command;
+
char *ignored_unknown; /* Pattern list of unknown tokens to ignore */
} Options;
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: ssh.1,v 1.414 2020/07/15 05:40:05 jmc Exp $
-.Dd $Mdocdate: July 15 2020 $
+.\" $OpenBSD: ssh.1,v 1.415 2020/12/22 00:15:23 djm Exp $
+.Dd $Mdocdate: December 22 2020 $
.Dt SSH 1
.Os
.Sh NAME
.It KbdInteractiveAuthentication
.It KbdInteractiveDevices
.It KexAlgorithms
+.It KnownHostsCommand
.It LocalCommand
.It LocalForward
.It LogLevel
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: ssh_config.5,v 1.338 2020/10/16 14:34:33 jmc Exp $
-.Dd $Mdocdate: October 16 2020 $
+.\" $OpenBSD: ssh_config.5,v 1.339 2020/12/22 00:15:23 djm Exp $
+.Dd $Mdocdate: December 22 2020 $
.Dt SSH_CONFIG 5
.Os
.Sh NAME
.Pp
The list of available key exchange algorithms may also be obtained using
.Qq ssh -Q kex .
+.It Cm KnownHostsCommand
+Specifies a command to use to obtain a list of host keys, additional to
+those listed in
+.Cm UserKnownHostsFile
+and
+.Cm GlobalKnownHostsFile .
+This command is executed after the files have been read.
+It may write host keys lines to standard output in identical format to the
+usual files (described in the
+.Sx VERIFYING HOST KEYS
+section in
+.Xr ssh 1 ) .
+Arguments to
+.Cm KnownHostsCommand
+accept the tokens described in the
+.Sx TOKENS
+section.
+The command may be invoked multiple times per connection: when preparing
+the preference list of host key algorithms to use, again to obtain the
+host key for the requested host name and, if
+.Cm CheckHostIP
+is enabled, one more time to obtain the host key matching the server's
+address.
+If the command exits abnormally or returns a non-zero exit status then the
+connection is terminated.
.It Cm LocalCommand
Specifies a command to execute on the local machine after successfully
connecting to the server.
Hash of %l%h%p%r.
.It %d
Local user's home directory.
+.It %f
+The fingerprint of the server's host key.
+.It %H
+The
+.Pa known_hosts
+hostname or address that is being searched for.
.It %h
The remote hostname.
+.It %I
+A string describing the reason for a
+.Cm KnownHostsCommand
+execution; either
+.Cm "ADDRESS"
+when looking up a host by address (only when
+.Cm CheckHostIP
+is enabled),
+.Cm "HOSTNAME"
+when searching by hostname or
+.Cm "ORDER"
+when preparing the host key algorithm preference list to use for the
+destination host.
.It %i
The local user ID.
+.It %K
+The base64 encoded host key.
.It %k
The host key alias if specified, otherwise the orignal remote hostname given
on the command line.
tunnel forwarding was requested, or
.Qq NONE
otherwise.
+.It %t
+The type of the server host key, e.g.
+.Cm ssh-ed25519
.It %u
The local username.
.El
.Cm ControlPath ,
.Cm IdentityAgent ,
.Cm IdentityFile ,
+.Cm KnownHostsCommand ,
.Cm LocalForward ,
.Cm Match exec ,
.Cm RemoteCommand ,
.Cm UserKnownHostsFile
accept the tokens %%, %C, %d, %h, %i, %L, %l, %n, %p, %r, and %u.
.Pp
+.Cm KnownHostsCommand
+additionally accepts the tokens %f, %H, %I, %K and %t.
+.Pp
.Cm Hostname
accepts the tokens %% and %h.
.Pp
.Cm ControlPath ,
.Cm IdentityAgent ,
.Cm IdentityFile
+.Cm KnownHostsCommand ,
and
.Cm UserKnownHostsFile
support environment variables.
-/* $OpenBSD: sshconnect.c,v 1.348 2020/12/20 23:40:19 djm Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.349 2020/12/22 00:15:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
return ret;
}
+void
+load_hostkeys_command(struct hostkeys *hostkeys, const char *command_template,
+ const char *invocation, const struct ssh_conn_info *cinfo,
+ const struct sshkey *host_key, const char *hostfile_hostname)
+{
+ int r, i, ac = 0;
+ char *key_fp = NULL, *keytext = NULL, *tmp;
+ char *command = NULL, *tag = NULL, **av = NULL;
+ FILE *f = NULL;
+ pid_t pid;
+ void (*osigchld)(int);
+
+ xasprintf(&tag, "KnownHostsCommand-%s", invocation);
+
+ if (host_key != NULL) {
+ if ((key_fp = sshkey_fingerprint(host_key,
+ options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+ fatal_f("sshkey_fingerprint failed");
+ if ((r = sshkey_to_base64(host_key, &keytext)) != 0)
+ fatal_fr(r, "sshkey_to_base64 failed");
+ }
+ /*
+ * NB. all returns later this function should go via "out" to
+ * ensure the original SIGCHLD handler is restored properly.
+ */
+ osigchld = ssh_signal(SIGCHLD, SIG_DFL);
+
+ /* Turn the command into an argument vector */
+ if (argv_split(command_template, &ac, &av) != 0) {
+ error("%s \"%s\" contains invalid quotes", tag,
+ command_template);
+ goto out;
+ }
+ if (ac == 0) {
+ error("%s \"%s\" yielded no arguments", tag,
+ command_template);
+ goto out;
+ }
+ for (i = 1; i < ac; i++) {
+ tmp = percent_dollar_expand(av[i],
+ DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
+ "H", hostfile_hostname,
+ "I", invocation,
+ "t", host_key == NULL ? "NONE" : sshkey_ssh_name(host_key),
+ "f", key_fp == NULL ? "NONE" : key_fp,
+ "K", keytext == NULL ? "NONE" : keytext,
+ (char *)NULL);
+ if (tmp == NULL)
+ fatal_f("percent_expand failed");
+ free(av[i]);
+ av[i] = tmp;
+ }
+ /* Prepare a printable command for logs, etc. */
+ command = argv_assemble(ac, av);
+
+ if ((pid = subprocess(tag, command, ac, av, &f,
+ SSH_SUBPROCESS_STDOUT_CAPTURE|SSH_SUBPROCESS_UNSAFE_PATH|
+ SSH_SUBPROCESS_PRESERVE_ENV, NULL, NULL, NULL)) == 0)
+ goto out;
+
+ load_hostkeys_file(hostkeys, hostfile_hostname, tag, f, 1);
+
+ if (exited_cleanly(pid, tag, command, 0) != 0)
+ fatal("KnownHostsCommand failed");
+
+ out:
+ if (f != NULL)
+ fclose(f);
+ ssh_signal(SIGCHLD, osigchld);
+ for (i = 0; i < ac; i++)
+ free(av[i]);
+ free(av);
+ free(tag);
+ free(command);
+ free(key_fp);
+ free(keytext);
+}
+
/*
* check whether the supplied host key is valid, return -1 if the key
* is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
struct sockaddr *hostaddr, u_short port,
struct sshkey *host_key, int readonly, int clobber_port,
char **user_hostfiles, u_int num_user_hostfiles,
- char **system_hostfiles, u_int num_system_hostfiles)
+ char **system_hostfiles, u_int num_system_hostfiles,
+ const char *hostfile_command)
{
HostStatus host_status = -1, ip_status = -1;
struct sshkey *raw_key = NULL;
load_hostkeys(host_hostkeys, host, user_hostfiles[i], 0);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(host_hostkeys, host, system_hostfiles[i], 0);
+ if (hostfile_command != NULL && !clobber_port) {
+ load_hostkeys_command(host_hostkeys, hostfile_command,
+ "HOSTNAME", cinfo, host_key, host);
+ }
ip_hostkeys = NULL;
if (!want_cert && options.check_host_ip) {
load_hostkeys(ip_hostkeys, ip, user_hostfiles[i], 0);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(ip_hostkeys, ip, system_hostfiles[i], 0);
+ if (hostfile_command != NULL && !clobber_port) {
+ load_hostkeys_command(ip_hostkeys, hostfile_command,
+ "ADDRESS", cinfo, host_key, ip);
+ }
}
retry:
host_status = check_key_in_hostkeys(host_hostkeys, host_key,
&host_found);
- /* If no host files were specified, then don't try to touch them */
- if (!readonly && num_user_hostfiles == 0)
+ /*
+ * If there are no hostfiles, or if the hostkey was found via
+ * KnownHostsCommand, then don't try to touch the disk.
+ */
+ if (!readonly && (num_user_hostfiles == 0 ||
+ (host_found != NULL && host_found->note != 0)))
readonly = RDONLY;
/*
debug3_f("host key found in GlobalKnownHostsFile; "
"disabling UpdateHostkeys");
}
+ if (options.update_hostkeys != 0 && host_found->note) {
+ options.update_hostkeys = 0;
+ debug3_f("host key found via KnownHostsCommand; "
+ "disabling UpdateHostkeys");
+ }
if (options.check_host_ip && ip_status == HOST_NEW) {
if (readonly || want_cert)
logit("%s host key for IP address "
if (check_host_key(hostname, cinfo, hostaddr, 0,
host_key, ROQUIET, 1,
user_hostfiles, num_user_hostfiles,
- system_hostfiles, num_system_hostfiles) == 0) {
+ system_hostfiles, num_system_hostfiles,
+ hostfile_command) == 0) {
debug("found matching key w/out port");
break;
}
}
r = check_host_key(host, cinfo, hostaddr, options.port, host_key,
RDRW, 0, options.user_hostfiles, options.num_user_hostfiles,
- options.system_hostfiles, options.num_system_hostfiles);
+ options.system_hostfiles, options.num_system_hostfiles,
+ options.known_hosts_command);
out:
sshkey_free(plain);
-/* $OpenBSD: sshconnect.h,v 1.45 2020/12/20 23:40:19 djm Exp $ */
+/* $OpenBSD: sshconnect.h,v 1.46 2020/12/22 00:15:23 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
void maybe_add_key_to_agent(const char *, struct sshkey *,
const char *, const char *);
+
+void load_hostkeys_command(struct hostkeys *, const char *,
+ const char *, const struct ssh_conn_info *,
+ const struct sshkey *, const char *);
-/* $OpenBSD: sshconnect2.c,v 1.338 2020/12/20 23:40:19 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.339 2020/12/22 00:15:23 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Damien Miller. All rights reserved.
load_hostkeys(hostkeys, hostname,
options.system_hostfiles[i], 0);
}
+ if (options.known_hosts_command != NULL) {
+ load_hostkeys_command(hostkeys, options.known_hosts_command,
+ "ORDER", cinfo, NULL, host);
+ }
/*
* If a plain public key exists that matches the type of the best
* preference HostkeyAlgorithms, then use the whole list as is.
(*first == '\0' || *last == '\0') ? "" : ",", last);
if (*first != '\0')
debug3_f("prefer hostkeyalgs: %s", first);
-
+ else
+ debug3_f("no algorithms matched; accept original");
out:
free(best);
free(first);
projects / thirdparty / openssh-portable.git / commitdiff
