GUACAMOLE-2319: Fix SFTP symlink dirs shown as files when root is not system root.

src/common-ssh/common-ssh/sftp.h

@@ -99,10 +99,18 @@ typedef struct guac_common_ssh_sftp_ls_state {
     LIBSSH2_SFTP_HANDLE* directory;
 
     /**
-     * The absolute path of the directory being listed.
+     * The absolute path of the directory being listed, as exposed to the
+     * client via the Guacamole protocol stream name.
      */
     char directory_name[GUAC_COMMON_SSH_SFTP_MAX_PATH];
 
+    /**
+     * The real, server-side filesystem path of the directory being listed,
+     * including any configured SFTP root prefix. Used to resolve symlinks
+     * during listing when the SFTP root is not "/".
+     */
+    char directory_real_path[GUAC_COMMON_SSH_SFTP_MAX_PATH];
+
     /**
      * The current state of the JSON directory object being written.
      */

src/common-ssh/sftp.c

@@ -649,8 +649,12 @@ static int guac_common_ssh_sftp_ls_ack_handler(guac_user* user,
         }
 
         /* Stat explicitly if symbolic link (might point to directory) */
-        if (LIBSSH2_SFTP_S_ISLNK(attributes.permissions))
-            libssh2_sftp_stat(sftp, absolute_path, &attributes);
+        if (LIBSSH2_SFTP_S_ISLNK(attributes.permissions)) {
+            char real_path[GUAC_COMMON_SSH_SFTP_MAX_PATH];
+            if (guac_ssh_append_filename(real_path,
+                        list_state->directory_real_path, filename))
+                libssh2_sftp_stat(sftp, real_path, &attributes);
+        }
 
         /* Determine mimetype */
         const char* mimetype;
@@ -791,6 +795,9 @@ static int guac_common_ssh_sftp_get_handler(guac_user* user,
             return 0;
         }
 
+        guac_strlcpy(list_state->directory_real_path, fullpath,
+                sizeof(list_state->directory_real_path));
+
         /* Allocate stream for body */
         guac_stream* stream = guac_user_alloc_stream(user);
         stream->ack_handler = guac_common_ssh_sftp_ls_ack_handler;