#5802: Don't make assumptions of remote path validity in transmission-remote

Defer validity checks until path gets to the remote side, where they
actually make sense. Add simple checks for download directory path to
ensure it's not relative, since one cannot know what current working
directory of the remote process is.

daemon/remote.c

@@ -490,43 +490,6 @@ static char * netrc = NULL;
 static char * sessionId = NULL;
 static bool UseSSL = false;
 
-static char*
-tr_getcwd (void)
-{
-  char * result;
-  tr_error * error = NULL;
-
-  result = tr_sys_dir_get_current (&error);
-
-  if (result == NULL)
-    {
-      fprintf (stderr, "getcwd error: \"%s\"", error->message);
-      tr_error_free (error);
-      result = tr_strdup ("");
-    }
-
-  return result;
-}
-
-static char*
-absolutify (const char * path)
-{
-  char * buf;
-
-  if (*path == '/')
-    {
-      buf = tr_strdup (path);
-    }
-  else
-    {
-      char * cwd = tr_getcwd ();
-      buf = tr_buildPath (cwd, path, NULL);
-      tr_free (cwd);
-    }
-
-  return buf;
-}
-
 static char*
 getEncodedMetainfo (const char * filename)
 {
@@ -2253,14 +2216,8 @@ processArgs (const char * rpcurl, int argc, const char ** argv)
             }
             case 'w':
             {
-                char * path = absolutify (optarg);
-                if (tadd)
-                    tr_variantDictAddStr (tr_variantDictFind (tadd, TR_KEY_arguments), TR_KEY_download_dir, path);
-                else {
-                    tr_variant * args = ensure_sset (&sset);
-                    tr_variantDictAddStr (args, TR_KEY_download_dir, path);
-                }
-                tr_free (path);
+                tr_variant * args = tadd ? tr_variantDictFind (tadd, TR_KEY_arguments) : ensure_sset (&sset);
+                tr_variantDictAddStr (args, TR_KEY_download_dir, optarg);
                 break;
             }
             case 850:

libtransmission/file-posix.c

@@ -258,6 +258,14 @@ tr_sys_path_get_info (const char        * path,
   return ret;
 }
 
+bool
+tr_sys_path_is_relative (const char * path)
+{
+  assert (path != NULL);
+
+  return path[0] != '/';
+}
+
 bool
 tr_sys_path_is_same (const char  * path1,
                      const char  * path2,

libtransmission/file-test.c

@@ -320,6 +320,49 @@ test_path_exists (void)
   return 0;
 }
 
+static int
+test_path_is_relative (void)
+{
+  check (tr_sys_path_is_relative (""));
+  check (tr_sys_path_is_relative ("."));
+  check (tr_sys_path_is_relative (".."));
+  check (tr_sys_path_is_relative ("x"));
+  check (tr_sys_path_is_relative ("\\"));
+  check (tr_sys_path_is_relative (":"));
+
+#ifdef _WIN32
+
+  check (tr_sys_path_is_relative ("/"));
+  check (tr_sys_path_is_relative ("//x"));
+  check (tr_sys_path_is_relative ("\\x"));
+  check (tr_sys_path_is_relative ("\\x\\y"));
+  check (tr_sys_path_is_relative ("C:x"));
+  check (tr_sys_path_is_relative ("C:x\\y"));
+
+  check (!tr_sys_path_is_relative ("\\\\"));
+  check (!tr_sys_path_is_relative ("\\\\x"));
+  check (!tr_sys_path_is_relative ("\\\\x\\y"));
+  check (!tr_sys_path_is_relative ("\\\\.\\x"));
+
+  check (!tr_sys_path_is_relative ("a:"));
+  check (!tr_sys_path_is_relative ("a:\\"));
+  check (!tr_sys_path_is_relative ("a:/"));
+  check (!tr_sys_path_is_relative ("Z:"));
+  check (!tr_sys_path_is_relative ("Z:\\"));
+  check (!tr_sys_path_is_relative ("Z:/"));
+
+#else /* _WIN32 */
+
+  check (!tr_sys_path_is_relative ("/"));
+  check (!tr_sys_path_is_relative ("/x"));
+  check (!tr_sys_path_is_relative ("/x/y"));
+  check (!tr_sys_path_is_relative ("//x"));
+
+#endif /* _WIN32 */
+
+  return 0;
+}
+
 static int
 test_path_is_same (void)
 {
@@ -1401,6 +1444,7 @@ main (void)
     {
       test_get_info,
       test_path_exists,
+      test_path_is_relative,
       test_path_is_same,
       test_path_resolve,
       test_path_basename_dirname,

libtransmission/file-win32.c

@@ -8,6 +8,7 @@
  */
 
 #include <assert.h>
+#include <ctype.h> /* isalpha () */
 #include <stdlib.h> /* _splitpath_s (), _makepath_s () */
 
 #include <shlobj.h> /* SHCreateDirectoryEx () */
@@ -327,6 +328,22 @@ tr_sys_path_get_info (const char        * path,
   return ret;
 }
 
+bool
+tr_sys_path_is_relative (const char * path)
+{
+  assert (path != NULL);
+
+  /* UNC path: `\\...`. */
+  if (path[0] == '\\' && path[1] == '\\')
+    return false;
+
+  /* Local path: `X:` or `X:\...`. */
+  if (isalpha (path[0]) && path[1] == ':' && (path[2] == '\0' || path[2] == '\\' || path[2] == '/'))
+    return false;
+
+  return true;
+}
+
 bool
 tr_sys_path_is_same (const char  * path1,
                      const char  * path2,

libtransmission/file.h

@@ -156,6 +156,17 @@ bool            tr_sys_path_get_info        (const char         * path,
 bool            tr_sys_path_exists          (const char         * path,
                                              struct tr_error   ** error);
 
+/**
+ * @brief Check whether path is relative.
+ *
+ * This function only analyzes the string, so no error reporting is needed.
+ *
+ * @param[in] path Path to file or directory.
+ *
+ * @return `True` if path is relative, `false` otherwise
+ */
+bool            tr_sys_path_is_relative     (const char         * path);
+
 /**
  * @brief Test to see if the two filenames point to the same file.
  *

libtransmission/rpcimpl.c

@@ -1343,6 +1343,9 @@ torrentSetLocation (tr_session               * session,
   if (!tr_variantDictFindStr (args_in, TR_KEY_location, &location, NULL))
     return "no location";
 
+  if (tr_sys_path_is_relative (location))
+    return "new location path is not absolute";
+
   bool move;
   int i, torrentCount;
   tr_torrent ** torrents = getTorrents (session, args_in, &torrentCount);
@@ -1711,10 +1714,17 @@ torrentAdd (tr_session               * session,
   if (!filename && !metainfo_base64)
     return "no filename or metainfo specified";
 
+  const char * download_dir = NULL;
+
+  if (tr_variantDictFindStr (args_in, TR_KEY_download_dir, &download_dir, NULL))
+    {
+      if (tr_sys_path_is_relative (download_dir))
+        return "download directory path is not absolute";
+    }
+
   int64_t i;
   bool boolVal;
   tr_variant * l;
-  const char * str;
   const char * cookies = NULL;
   tr_ctor * ctor = tr_ctorNew (session);
 
@@ -1722,8 +1732,8 @@ torrentAdd (tr_session               * session,
 
   tr_variantDictFindStr (args_in, TR_KEY_cookies, &cookies, NULL);
 
-  if (tr_variantDictFindStr (args_in, TR_KEY_download_dir, &str, NULL))
-    tr_ctorSetDownloadDir (ctor, TR_FORCE, str);
+  if (download_dir != NULL)
+    tr_ctorSetDownloadDir (ctor, TR_FORCE, download_dir);
 
   if (tr_variantDictFindBool (args_in, TR_KEY_paused, &boolVal))
     tr_ctorSetPaused (ctor, TR_FORCE, boolVal);