linux: fix copy_from_fd ownership

Closes: #2002

Signed-off-by: Erik Sjölund <erik.sjolund@gmail.com>

Author: eriksjolund

src/libcrun/linux.c

@@ -2124,19 +2124,16 @@ static int
 handle_tmpcopyup (libcrun_container_t *container, const char *rootfs, const char *target,
                   int copy_from_fd, libcrun_error_t *err)
 {
-  int destfd, tmpfd, ret;
-
+  int destfd, ret;
+  cleanup_close int tmpfd = copy_from_fd;
   destfd = safe_openat (get_private_data (container)->rootfsfd, rootfs, target,
                         O_CLOEXEC | O_DIRECTORY, 0, err);
   if (UNLIKELY (destfd < 0))
     return crun_error_wrap (err, "open `%s` to write for tmpcopyup", target);
 
-  /* take ownership for the fd.  */
-  tmpfd = get_and_reset (&copy_from_fd);
-
+  // copy_recursive_fd_to_fd closes tmpfd and destfd
   ret = copy_recursive_fd_to_fd (tmpfd, destfd, target, target, err);
-  close (destfd);
-  close (tmpfd);
+  tmpfd = -1;
 
   return ret;
 }
@@ -2339,7 +2336,9 @@ process_single_mount (libcrun_container_t *container, const char *rootfs,
 
   if (copy_from_fd >= 0)
     {
+      // handle_tmpcopyup closes copy_from_fd
       ret = handle_tmpcopyup (container, rootfs, target, copy_from_fd, err);
+      copy_from_fd = -1;
       if (UNLIKELY (ret < 0))
         return ret;
     }

src/libcrun/utils.c

@@ -2249,7 +2249,7 @@ copy_recursive_fd_to_fd (int srcdirfd, int dfd, const char *srcname, const char
           if (UNLIKELY (ret < 0))
             return ret;
 #endif
-
+          // copy_recursive_fd_to_fd closes srcfd and destfd
           ret = copy_recursive_fd_to_fd (srcfd, destfd, de->d_name, de->d_name, err);
           srcfd = destfd = -1;
           if (UNLIKELY (ret < 0))