tools/bootconfig: fix fd leak in load_xbc_file() on fstat failure

If fstat() fails after open() succeeds, the function returns without
closing the file descriptor. Also preserve errno across close(), since
close() may overwrite it before the error is returned.

Link: https://lore.kernel.org/all/[email protected]/

Fixes: 950313ebf7 ("tools: bootconfig: Add bootconfig command")
Signed-off-by: Josh Law <[email protected]>
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>

tools/bootconfig/main.c

@@ -162,8 +162,11 @@ static int load_xbc_file(const char *path, char **buf)
 	if (fd < 0)
 		return -errno;
 	ret = fstat(fd, &stat);
-	if (ret < 0)
-		return -errno;
+	if (ret < 0) {
+		ret = -errno;
+		close(fd);
+		return ret;
+	}
 
 	ret = load_xbc_fd(fd, buf, stat.st_size);