convert: avoid malloc of original file size

diff --git a/convert.c b/convert.c
index e0848226d21bbbeb26d9ac6217fe1e61ccc71fca..bdaec3411dfb93b3da6b78a0fac625d1fd3d4733 100644 (file)
--- a/convert.c
+++ b/convert.c
@@ -732,7 +732,7 @@ static int apply_single_file_filter(const char *path, const char *src, size_t le
        if (start_async(&async))
                return 0;       /* error was already reported */
 
-       if (strbuf_read(&nbuf, async.out, len) < 0) {
+       if (strbuf_read(&nbuf, async.out, 0) < 0) {
                err = error(_("read from external filter '%s' failed"), cmd);
        }
        if (close(async.out)) {