tar: fix race condition

Problem reported in:
https://lists.gnu.org/r/bug-tar/2022-03/msg00000.html
* src/extract.c (make_directories): Retry the file creation as
long as the directory exists, regardless of whether tar itself
created the directory.
Copyright-paperwork-exempt: Yes

diff --git a/src/extract.c b/src/extract.c
index 0753decfb203b99d627fa9f661b02b595280e579..fda4617d3fa906546cc0cd47f2058e9af4c44c5a 100644 (file)
--- a/src/extract.c
+++ b/src/extract.c
@@ -638,10 +638,9 @@ fixup_delayed_set_stat (char const *src, char const *dst)
 
 /* After a file/link/directory creation has failed due to ENOENT,
    create all required directories.  Return zero if all the required
-   directories were created, nonzero (issuing a diagnostic) otherwise.
-   Set *INTERDIR_MADE if at least one directory was created.  */
+   directories were created, nonzero (issuing a diagnostic) otherwise.  */
 static int
-make_directories (char *file_name, bool *interdir_made)
+make_directories (char *file_name)
 {
   char *cursor0 = file_name + FILE_SYSTEM_PREFIX_LEN (file_name);
   char *cursor;                        /* points into the file name */
@@ -685,7 +684,6 @@ make_directories (char *file_name, bool *interdir_made)
                          desired_mode, AT_SYMLINK_NOFOLLOW);
 
          print_for_mkdir (file_name, cursor - file_name, desired_mode);
-         *interdir_made = true;
          parent_end = NULL;
        }
       else
@@ -841,8 +839,11 @@ maybe_recoverable (char *file_name, bool regular, bool *interdir_made)
 
     case ENOENT:
       /* Attempt creating missing intermediate directories.  */
-      if (make_directories (file_name, interdir_made) == 0)
-       return RECOVER_OK;
+      if (make_directories (file_name) == 0)
+       {
+         *interdir_made = true;
+         return RECOVER_OK;
+       }
       break;
 
     default:
@@ -1944,12 +1945,11 @@ rename_directory (char *src, char *dst)
   else
     {
       int e = errno;
-      bool interdir_made;
 
       switch (e)
        {
        case ENOENT:
-         if (make_directories (dst, &interdir_made) == 0)
+         if (make_directories (dst) == 0)
            {
              if (renameat (chdir_fd, src, chdir_fd, dst) == 0)
                return true;