ssh-keygen: implement "verify-required" certificate option

This was already documented when support for user-verified FIDO
keys was added, but the ssh-keygen(1) code was missing.

ok djm@

diff --git a/usr.bin/ssh/ssh-keygen.c b/usr.bin/ssh/ssh-keygen.c
index 30d9560..5faa1ce 100644 (file)
--- a/usr.bin/ssh/ssh-keygen.c
+++ b/usr.bin/ssh/ssh-keygen.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-keygen.c,v 1.452 2022/05/09 03:09:53 djm Exp $ */
+/* $OpenBSD: ssh-keygen.c,v 1.453 2022/05/31 14:05:12 naddy Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -121,6 +121,7 @@ static u_int64_t cert_valid_to = ~0ULL;
 #define CERTOPT_PTY                            (1<<3)
 #define CERTOPT_USER_RC                                (1<<4)
 #define CERTOPT_NO_REQUIRE_USER_PRESENCE       (1<<5)
+#define CERTOPT_REQUIRE_VERIFY                 (1<<6)
 #define CERTOPT_DEFAULT        (CERTOPT_X_FWD|CERTOPT_AGENT_FWD| \
                         CERTOPT_PORT_FWD|CERTOPT_PTY|CERTOPT_USER_RC)
 static u_int32_t certflags_flags = CERTOPT_DEFAULT;
@@ -1649,6 +1650,8 @@ finalise_cert_exts(void)
                cert_ext_add("force-command", certflags_command, 1);
        if (certflags_src_addr != NULL)
                cert_ext_add("source-address", certflags_src_addr, 1);
+       if ((certflags_flags & CERTOPT_REQUIRE_VERIFY) != 0)
+               cert_ext_add("verify-required", NULL, 1);
        /* extensions */
        if ((certflags_flags & CERTOPT_X_FWD) != 0)
                cert_ext_add("permit-X11-forwarding", NULL, 0);
@@ -1970,6 +1973,10 @@ add_cert_option(char *opt)
                certflags_flags &= ~CERTOPT_NO_REQUIRE_USER_PRESENCE;
        else if (strcasecmp(opt, "no-touch-required") == 0)
                certflags_flags |= CERTOPT_NO_REQUIRE_USER_PRESENCE;
+       else if (strcasecmp(opt, "no-verify-required") == 0)
+               certflags_flags &= ~CERTOPT_REQUIRE_VERIFY;
+       else if (strcasecmp(opt, "verify-required") == 0)
+               certflags_flags |= CERTOPT_REQUIRE_VERIFY;
        else if (strncasecmp(opt, "force-command=", 14) == 0) {
                val = opt + 14;
                if (*val == '\0')
@@ -2028,6 +2035,9 @@ show_options(struct sshbuf *optbuf, int in_critical)
                                fatal_fr(r, "parse critical");
                        printf(" %s\n", arg);
                        free(arg);
+               } else if (in_critical &&
+                   strcmp(name, "verify-required") == 0) {
+                       printf("\n");
                } else if (sshbuf_len(option) > 0) {
                        hex = sshbuf_dtob16(option);
                        printf(" UNKNOWN OPTION: %s (len %zu)\n",