upstream: Add a sshd_config "Include" directive to allow inclusion

of files. This has sensible semantics wrt Match blocks and accepts glob(3)
patterns to specify the included files. Based on patch by Jakub Jelen in
bz2468; feedback and ok markus@

OpenBSD-Commit-ID: 36ed0e845b872e33f03355b936a4fff02d5794ff

1 files changed, 49 insertions, 16 deletions

diff --git a/sshd.c b/sshd.c
index 46fdf7ee3..57fab0425 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.545 2020/01/24 23:56:01 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.546 2020/01/31 22:42:45 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -251,6 +251,9 @@ struct sshauthopt *auth_opts = NULL;
 /* sshd_config buffer */
 struct sshbuf *cfg;
 
+/* Included files from the configuration file */
+struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
+
 /* message to be displayed after login */
 struct sshbuf *loginmsg;
 
@@ -870,30 +873,45 @@ usage(void)
 static void
 send_rexec_state(int fd, struct sshbuf *conf)
 {
-        struct sshbuf *m;
+        struct sshbuf *m = NULL, *inc = NULL;
+        struct include_item *item = NULL;
         int r;
 
         debug3("%s: entering fd = %d config len %zu", __func__, fd,
             sshbuf_len(conf));
 
+        if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
+                fatal("%s: sshbuf_new failed", __func__);
+
+        /* pack includes into a string */
+        TAILQ_FOREACH(item, &includes, entry) {
+                if ((r = sshbuf_put_cstring(inc, item->selector)) != 0 ||
+                    (r = sshbuf_put_cstring(inc, item->filename)) != 0 ||
+                    (r = sshbuf_put_stringb(inc, item->contents)) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
+        }
+
         /*
          * Protocol from reexec master to child:
          *      string  configuration
-         *      string rngseed          (only if OpenSSL is not self-seeded)
+         *      string  included_files[] {
+         *              string  selector
+         *              string  filename
+         *              string  contents
+         *      }
+         *      string  rng_seed (if required)
          */
-        if ((m = sshbuf_new()) == NULL)
-                fatal("%s: sshbuf_new failed", __func__);
-        if ((r = sshbuf_put_stringb(m, conf)) != 0)
+        if ((r = sshbuf_put_stringb(m, conf)) != 0 ||
+            (r = sshbuf_put_stringb(m, inc)) != 0)
                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
-
 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
         rexec_send_rng_seed(m);
 #endif
-
         if (ssh_msg_send(fd, 0, m) == -1)
                 fatal("%s: ssh_msg_send failed", __func__);
 
         sshbuf_free(m);
+        sshbuf_free(inc);
 
         debug3("%s: done", __func__);
 }
@@ -901,14 +919,15 @@ send_rexec_state(int fd, struct sshbuf *conf)
 static void
 recv_rexec_state(int fd, struct sshbuf *conf)
 {
-        struct sshbuf *m;
+        struct sshbuf *m, *inc;
         u_char *cp, ver;
         size_t len;
         int r;
+        struct include_item *item;
 
         debug3("%s: entering fd = %d", __func__, fd);
 
-        if ((m = sshbuf_new()) == NULL)
+        if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
                 fatal("%s: sshbuf_new failed", __func__);
         if (ssh_msg_recv(fd, m) == -1)
                 fatal("%s: ssh_msg_recv failed", __func__);
@@ -916,14 +935,28 @@ recv_rexec_state(int fd, struct sshbuf *conf)
                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
         if (ver != 0)
                 fatal("%s: rexec version mismatch", __func__);
-        if ((r = sshbuf_get_string(m, &cp, &len)) != 0)
-                fatal("%s: buffer error: %s", __func__, ssh_err(r));
-        if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
+        if ((r = sshbuf_get_string(m, &cp, &len)) != 0 ||
+            (r = sshbuf_get_stringb(m, inc)) != 0)
                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
         rexec_recv_rng_seed(m);
 #endif
 
+        if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
+                fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+        while (sshbuf_len(inc) != 0) {
+                item = xcalloc(1, sizeof(*item));
+                if ((item->contents = sshbuf_new()) == NULL)
+                        fatal("%s: sshbuf_new failed", __func__);
+                if ((r = sshbuf_get_cstring(inc, &item->selector, NULL)) != 0 ||
+                    (r = sshbuf_get_cstring(inc, &item->filename, NULL)) != 0 ||
+                    (r = sshbuf_get_stringb(inc, item->contents)) != 0)
+                        fatal("%s: buffer error: %s", __func__, ssh_err(r));
+                TAILQ_INSERT_TAIL(&includes, item, entry);
+        }
+
         free(cp);
         sshbuf_free(m);
 
@@ -1600,7 +1633,7 @@ main(int ac, char **av)
                 case 'o':
                         line = xstrdup(optarg);
                         if (process_server_config_line(&options, line,
-                            "command-line", 0, NULL, NULL) != 0)
+                            "command-line", 0, NULL, NULL, &includes) != 0)
                                 exit(1);
                         free(line);
                         break;
@@ -1669,7 +1702,7 @@ main(int ac, char **av)
                 load_server_config(config_file_name, cfg);
 
         parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
-            cfg, NULL);
+            cfg, &includes, NULL);
 
         /* Fill in default values for those options not explicitly set. */
         fill_default_server_options(&options);
@@ -1895,7 +1928,7 @@ main(int ac, char **av)
                 if (connection_info == NULL)
                         connection_info = get_connection_info(ssh, 0, 0);
                 connection_info->test = 1;
-                parse_server_match_config(&options, connection_info);
+                parse_server_match_config(&options, &includes, connection_info);
                 dump_config(&options);
         }