1 files changed, 149 insertions, 1 deletions

diff --git a/auth-options.c b/auth-options.c
index ab085c233..396bda62f 100644
--- a/auth-options.c
+++ b/auth-options.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth-options.c,v 1.44 2009/01/22 10:09:16 djm Exp $ */
+/* $OpenBSD: auth-options.c,v 1.45 2010/02/26 20:29:54 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -44,6 +44,7 @@ int no_agent_forwarding_flag = 0;
 int no_x11_forwarding_flag = 0;
 int no_pty_flag = 0;
 int no_user_rc = 0;
+int key_is_cert_authority = 0;
 
 /* "command=" option. */
 char *forced_command = NULL;
@@ -64,6 +65,7 @@ auth_clear_options(void)
         no_pty_flag = 0;
         no_x11_forwarding_flag = 0;
         no_user_rc = 0;
+        key_is_cert_authority = 0;
         while (custom_environment) {
                 struct envstring *ce = custom_environment;
                 custom_environment = ce->next;
@@ -96,6 +98,12 @@ auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
                 return 1;
 
         while (*opts && *opts != ' ' && *opts != '\t') {
+                cp = "cert-authority";
+                if (strncasecmp(opts, cp, strlen(cp)) == 0) {
+                        key_is_cert_authority = 1;
+                        opts += strlen(cp);
+                        goto next_option;
+                }
                 cp = "no-port-forwarding";
                 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
                         auth_debug_add("Port forwarding disabled.");
@@ -374,3 +382,143 @@ bad_option:
         /* deny access */
         return 0;
 }
+
+/*
+ * Set options from certificate constraints. These supersede user key options
+ * so this must be called after auth_parse_options().
+ */
+int
+auth_cert_constraints(Buffer *c_orig, struct passwd *pw)
+{
+        u_char *name = NULL, *data_blob = NULL;
+        u_int len;
+        Buffer c, data;
+        int ret = -1;
+
+        int cert_no_port_forwarding_flag = 1;
+        int cert_no_agent_forwarding_flag = 1;
+        int cert_no_x11_forwarding_flag = 1;
+        int cert_no_pty_flag = 1;
+        int cert_no_user_rc = 1;
+        char *cert_forced_command = NULL;
+        int cert_source_address_done = 0;
+
+        buffer_init(&data);
+
+        /* Make copy to avoid altering original */
+        buffer_init(&c);
+        buffer_append(&c, buffer_ptr(c_orig), buffer_len(c_orig));
+
+        while (buffer_len(&c) > 0) {
+                if ((name = buffer_get_string_ret(&c, NULL)) == NULL ||
+                    (data_blob = buffer_get_string_ret(&c, &len)) == NULL) {
+                        error("Certificate constraints corrupt");
+                        goto out;
+                }
+                buffer_append(&data, data_blob, len);
+                debug3("found certificate constraint \"%.100s\" len %u",
+                    name, len);
+                if (strcmp(name, "permit-X11-forwarding") == 0)
+                        cert_no_x11_forwarding_flag = 0;
+                else if (strcmp(name, "permit-agent-forwarding") == 0)
+                        cert_no_agent_forwarding_flag = 0;
+                else if (strcmp(name, "permit-port-forwarding") == 0)
+                        cert_no_port_forwarding_flag = 0;
+                else if (strcmp(name, "permit-pty") == 0)
+                        cert_no_pty_flag = 0;
+                else if (strcmp(name, "permit-user-rc") == 0)
+                        cert_no_user_rc = 0;
+                else if (strcmp(name, "force-command") == 0) {
+                        char *command = buffer_get_string_ret(&data, NULL);
+
+                        if (command == NULL) {
+                                error("Certificate constraint \"%s\" corrupt",
+                                    name);
+                                goto out;
+                        }
+                        if (cert_forced_command != NULL) {
+                                error("Certificate has multiple "
+                                    "forced-command constraints");
+                                xfree(command);
+                                goto out;
+                        }
+                        cert_forced_command = command;
+                } else if (strcmp(name, "source-address") == 0) {
+                        char *allowed = buffer_get_string_ret(&data, NULL);
+                        const char *remote_ip = get_remote_ipaddr();
+                        
+                        if (allowed == NULL) {
+                                error("Certificate constraint \"%s\" corrupt",
+                                    name);
+                                goto out;
+                        }
+                        if (cert_source_address_done++) {
+                                error("Certificate has multiple "
+                                    "source-address constraints");
+                                xfree(allowed);
+                                goto out;
+                        }
+                        switch (addr_match_cidr_list(remote_ip, allowed)) {
+                        case 1:
+                                /* accepted */
+                                xfree(allowed);
+                                break;
+                        case 0:
+                                /* no match */
+                                logit("Authentication tried for %.100s with "
+                                    "valid certificate but not from a "
+                                    "permitted host (ip=%.200s).",
+                                    pw->pw_name, remote_ip);
+                                auth_debug_add("Your address '%.200s' is not "
+                                    "permitted to use this certificate for "
+                                    "login.", remote_ip);
+                                xfree(allowed);
+                                goto out;
+                        case -1:
+                                error("Certificate source-address contents "
+                                    "invalid");
+                                xfree(allowed);
+                                goto out;
+                        }
+                } else {
+                        error("Certificate constraint \"%s\" is not supported",
+                            name);
+                        goto out;
+                }
+
+                if (buffer_len(&data) != 0) {
+                        error("Certificate constraint \"%s\" corrupt "
+                            "(extra data)", name);
+                        goto out;
+                }
+                buffer_clear(&data);
+                xfree(name);
+                xfree(data_blob);
+                name = data_blob = NULL;
+        }
+
+        /* successfully parsed all constraints */
+        ret = 0;
+
+        no_port_forwarding_flag |= cert_no_port_forwarding_flag;
+        no_agent_forwarding_flag |= cert_no_agent_forwarding_flag;
+        no_x11_forwarding_flag |= cert_no_x11_forwarding_flag;
+        no_pty_flag |= cert_no_pty_flag;
+        no_user_rc |= cert_no_user_rc;
+        /* CA-specified forced command supersedes key option */
+        if (cert_forced_command != NULL) {
+                if (forced_command != NULL)
+                        xfree(forced_command);
+                forced_command = cert_forced_command;
+        }
+        
+ out:
+        if (name != NULL)
+                xfree(name);
+        if (data_blob != NULL)
+                xfree(data_blob);
+        buffer_free(&data);
+        buffer_free(&c);
+        return ret;
+}
+