upstream: Introduce a new API for handling authorized_keys options.

This API parses options to a dedicated structure rather than the old API's
approach of setting global state. It also includes support for merging
options, e.g. from authorized_keys, authorized_principals and/or
certificates.

feedback and ok markus@

OpenBSD-Commit-ID: 98badda102cd575210d7802943e93a34232c80a2

1 files changed, 69 insertions, 1 deletions

diff --git a/auth-options.h b/auth-options.h
index 547f01635..0dbfc325e 100644
--- a/auth-options.h
+++ b/auth-options.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth-options.h,v 1.23 2017/05/31 10:54:00 markus Exp $ */
+/* $OpenBSD: auth-options.h,v 1.24 2018/03/03 03:06:02 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -15,6 +15,9 @@
 #ifndef AUTH_OPTIONS_H
 #define AUTH_OPTIONS_H
 
+struct passwd;
+struct sshkey;
+
 /* Linked list of custom environment strings */
 struct envstring {
         struct envstring *next;
@@ -37,4 +40,69 @@ int	auth_parse_options(struct passwd *, char *, const char *, u_long);
 void    auth_clear_options(void);
 int     auth_cert_options(struct sshkey *, struct passwd *, const char **);
 
+/* authorized_keys options handling */
+
+/*
+ * sshauthopt represents key options parsed from authorized_keys or
+ * from certificate extensions/options.
+ */
+struct sshauthopt {
+        /* Feature flags */
+        int permit_port_forwarding_flag;
+        int permit_agent_forwarding_flag;
+        int permit_x11_forwarding_flag;
+        int permit_pty_flag;
+        int permit_user_rc;
+
+        /* "restrict" keyword was invoked */
+        int restricted;
+
+        /* Certificate-related options */
+        int cert_authority;
+        char *cert_principals;
+
+        int force_tun_device;
+        char *force_command;
+
+        /* Custom environment */
+        size_t nenv;
+        char **env;
+
+        /* Permitted port forwardings */
+        size_t npermitopen;
+        char **permitopen;
+
+        /*
+         * Permitted host/addresses (comma-separated)
+         * Caller must check source address matches both lists (if present).
+         */
+        char *required_from_host_cert;
+        char *required_from_host_keys;
+};
+
+struct sshauthopt *sshauthopt_new(void);
+struct sshauthopt *sshauthopt_new_with_keys_defaults(void);
+void sshauthopt_free(struct sshauthopt *opts);
+struct sshauthopt *sshauthopt_copy(const struct sshauthopt *orig);
+int sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m, int);
+int sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **opts);
+
+/*
+ * Parse authorized_keys options. Returns an options structure on success
+ * or NULL on failure. Will set errstr on failure.
+ */
+struct sshauthopt *sshauthopt_parse(const char *s, const char **errstr);
+
+/*
+ * Parse certification options to a struct sshauthopt.
+ * Returns options on success or NULL on failure.
+ */
+struct sshauthopt *sshauthopt_from_cert(struct sshkey *k);
+
+/*
+ * Merge key options.
+ */
+struct sshauthopt *sshauthopt_merge(const struct sshauthopt *primary,
+    const struct sshauthopt *additional, const char **errstrp);
+
 #endif